[A Study on the Relationship Between Insulin-like Growth Factor, Insulin-like Growth Factor-binding Protein-3 and Fetal Growth Retardation]

Zhonghua Fu Chan Ke Za Zhi. Feb, 2002  |  Pubmed ID: 11953064

To explore the effect of insulin-like growth factor-I (IGF-I), insulin-like growth factor-II (IGF-II) and insulin-like growth factor-binding protein-3 (IGFBP-3) on the fetal growth.

An Expanded View of Bacterial DNA Replication

Proceedings of the National Academy of Sciences of the United States of America. Jun, 2002  |  Pubmed ID: 12060778

A protein-interaction network centered on the replication machinery of Bacillus subtilis was generated by genome-wide two-hybrid screens and systematic specificity assays. The network consists of 91 specific interactions linking 69 proteins. Over one fourth of the interactions take place between homologues of proteins known to interact in other organisms, indicating the high biological significance of the other interactions we report. These interactions provide insights on the relations of DNA replication with recombination and repair, membrane-bound protein complexes, and signaling pathways. They also lead to the biological role of unknown proteins, as illustrated for the highly conserved YabA, which is shown here to act in initiation control. Thus, our interaction map provides a valuable tool for the discovery of aspects of bacterial DNA replication.

A Large Dispersed Chromosomal Region Required for Chromosome Segregation in Sporulating Cells of Bacillus Subtilis

The EMBO Journal. Aug, 2002  |  Pubmed ID: 12145201

The cis-acting sequences required for chromosome segregation are poorly understood in most organisms, including bacteria. Sporulating cells of Bacillus subtilis undergo an unusual asymmetric cell division during which the origin of DNA replication (oriC) region of the chromosome migrates to an extreme polar position. We have now characterized the sequences required for this migration. We show that the previously characterized soj-spo0J chromosome segregation system is not essential for chromosome movement to the cell pole, so this must be driven by an additional segregation mechanism. Observations on a large set of precisely engineered chromosomal inversions and translocations have identified a polar localization region (PLR), which lies approximately 150-300 kbp to the left of oriC. Surprisingly, oriC itself has no involvement in this chromosome segregation system. Dissection of the PLR showed that it has internal functional redundancy, reminiscent of the large diffuse centromeres of most eukaryotic cells.

Amino Acid Substitution of Arginine 80 in 17beta-hydroxysteroid Dehydrogenase Type 3 and Its Effect on NADPH Cofactor Binding and Oxidation/reduction Kinetics

Biochimica Et Biophysica Acta. Nov, 2002  |  Pubmed ID: 12429500

17beta-Hydroxysteroid dehydrogenase type 3 (17beta-HSD-3) is a member of the short-chain dehydrogenase/reductase (SDR) family and is essential for the reductive conversion of inactive C(19)-steroid, androstenedione, to the biologically active androgen, testosterone, which plays a central role in the development of the male phenotype. Mutations that inactivate this enzyme give rise to a rare form of male pseudohermaphroditism, referred to as 17beta-HSD-3 deficiency. One such mutation is the replacement of arginine at position 80 with glutamine, compromising enzyme activity by increasing the cofactor binding constant 60-fold. In the absence of a 17beta-HSD-3 crystal structure, we have grafted its amino acid sequence for the NADPH binding site on the X-ray crystal structures of glutathione reductase (Protein Data Bank code 1gra) and 17beta-HSD type 1 (Protein Data Bank codes 1fdv and 1fdu) where we find the trunk of the arginine 80 side chain forms part of the hydrophobic pocket for the purine ring of adenosine while its guanidinium moiety interacts with the 2'-phosphate to both stabilize cofactor binding and neutralize its intrinsic negative charge through two hydrogen bonds. To qualitatively assess the role arginine 80 plays in both selecting and stabilizing NADPH binding, it was replaced with each amino acid and the mutant enzymes subjected to enzymatic analysis. There are only seven enzymes exhibiting any measurable enzymatic activity with arginine approximately lysine>leucine>glutamine>methionine>tyrosine>isoleucine. With an aspartic acid at position 58 in 17beta-HSD-3 occupying the equivalent space in the cofactor binding pocket as arginine 224 in glutathione reductase or serine 12 in 17beta-HSD-1, there was an expectation that some of the mutants might use NADH as a cofactor. In no case was NADH found to substitute for NADPH.

Localization of Nav1.5 Sodium Channel Protein in the Mouse Brain

Neuroreport. Dec, 2002  |  Pubmed ID: 12499865

Na(v)1.5 or SCN5A is a member of the voltage-dependent family of sodium channels. The distribution of Na(v)1.5 protein was investigated in the mouse brain using immunohistochemistry. Immunostaining with a Na(v)1.5-specific antibody revealed that Na(v)1.5 protein was localized in certain distinct regions of brain including the cerebral cortex, thalamus, hypothalamus, basal ganglia, cerebellum and brain stem. Notably, we found that Na(v)1.5 protein co-localized with neurofilaments and clustered at a high density in the neuronal processes, mainly axons. These results suggest that Na(v)1.5 protein may play a role in the physiology of the central nervous system (generation and propagation of electrical signals by axons).

A Thin-layer, Liquid-based Pap Test for Mass Screening in an Area of China with a High Incidence of Cervical Carcinoma. A Cross-sectional, Comparative Study

Acta Cytologica. Jan-Feb, 2003  |  Pubmed ID: 12585030

To confirm the accuracy of the ThinPrep Pap Test (Cytyc Corp., Boxborough, Massachusetts, U.S.A.) on the basis of histologic diagnosis by biopsy and the detection of human papillomavirus (HPV) DNA in mass screening.

Identification of Minimal Peptide Sequences in the (8-20) Domain of Human Islet Amyloid Polypeptide Involved in Fibrillogenesis

Journal of Structural Biology. Mar, 2003  |  Pubmed ID: 12648568

We have examined a series of overlapping peptide fragments from the 8-20 region of human islet amyloid polypeptide (IAPP) with the objective of defining the smallest fibril-forming domain. Peptide fragments corresponding to LANFLV (residues 12-17) and FLVHSS (residues 15-20) were strong enhancers of beta-sheet transition and fibril formation. Negative stain electron microscopy illustrated the ability of these peptide fragments to form fibrils independently when incubated alone in solution. Circular dichroism analysis revealed that when full-length human IAPP was incubated in the presence of these two fragments, fibrillogenesis was accelerated. While the two fragments, LANFLV and FLVHSS, were able to enhance the recruitment of additional IAPP molecules during fibril formation, the "seeding" activity of these peptides had no effect on altering IAPP-induced cytotoxcity as determined by cell culture studies. Therefore, this study has identified two internal IAPP peptide fragments within the 8-20 domain that may have a role in enhancing the folding and aggregation of human IAPP. These fragments are the smallest sequences identified, within the 8-20 region of hIAPP, that can independently form fibrils, and that can interact with IAPP to assemble into fibrils with characteristics similar as those formed by human IAPP alone.

Temperature-modulated Diversity of TRPV4 Channel Gating: Activation by Physical Stresses and Phorbol Ester Derivatives Through Protein Kinase C-dependent and -independent Pathways

The Journal of Biological Chemistry. Jul, 2003  |  Pubmed ID: 12738791

The TRPV4 calcium-permeable channel was cloned from mouse kidney M-1 cells, and the effect of temperature modulation on channel gating/activation by physical and chemical signals was evaluated. A TRPV4 cDNA construct with a C-terminal V5 epitope was stably transfected into human embryonic kidney (HEK) 293 and Chinese hamster ovary cells resulting in high levels of expression at the plasma membrane. Channel activation was assessed from changes in calcium influx (fura-2 fluorescence measurements) or whole cell currents (patch clamp analysis). At room temperature (22-24 degrees C), exposure of TRPV4-transfected cells to hypotonic medium (225 mOsm/liter) or a non-protein kinase C (PKC)-activating phorbol ester derivative, 4alpha-phorbol 12,13-decanoate (100 nm), induces modest channel activation, whereas phorbol 12-myristate 13-acetate (100 nm), a PKC-activating phorbol ester, and shear stress (3-20 dyne/cm2) had minimal or no effect on channel activation. In contrast, at elevated temperatures (37 degrees C) the channel was rapidly activated by all stimuli. Inhibition of PKC by calphostin C (50 nm) or staurosporine (500 nm) abolished phorbol 12-myristate 13-acetate-induced activation of the channel without affecting the response to other stimuli. Ruthenium red (1 microm) effectively blocked the channel activity by all stimuli. It is concluded that temperature is a critical modulator of TRPV4 channel gating, leading to activation of the channel by a diverse range of microenvironmental chemical and physical signals utilizing a least two transduction pathways, one PKC-dependent and one PKC-independent. The convergence of multiple signals and transduction pathways on the same channel indicate that the channel functions as a molecular integrator of microenvironmental chemical and physical signals.

HER2/PI-3K/Akt Activation Leads to a Multidrug Resistance in Human Breast Adenocarcinoma Cells

Oncogene. May, 2003  |  Pubmed ID: 12761490

Growth factor receptor-mediated signal transduction has been implicated in conferring resistance to conventional chemotherapy on cancer cells. In this study, we delineated a pathway that involves HER2/PI-3K/Akt in mediating multidrug resistance in human breast cancer cells. We found that the cell lines that express both HER2 and HER3 appear to have a higher phosphorylation level of Akt (activated Akt). Transfection of HER2 in MCF7 breast cancer cells that express HER3 caused a phosphoinoside-3 kinase (PI-3K)-dependent activation of Akt, and was associated with an increased resistance of the cells to multiple chemotherapeutic agents (paclitaxel, doxorubicin, 5-fluorouracil, etoposide, and camptothecin). Selective inhibition of PI-3K or Akt activity with their respective dominant-negative expression vectors sensitized the cells to the induction of apoptosis by the chemotherapeutic agents. We further demonstrated that MCF7 cells expressing a constitutively active Akt, in which the phospholipid-interactive PH domain of Akt was replaced by a farnesylation sequence for constitutive membrane anchorage (DeltaPH-Akt1-farn), showed a similar increased resistance to the chemotherapeutic agents. Our results suggest that activation of Akt1 by HER2/PI-3K plays an important role in conferring a broad-spectrum chemoresistance on breast cancer cells and that Akt may therefore be a novel molecular target for therapies that would improve the outcome of patients with breast cancer.

RacA and the Soj-Spo0J System Combine to Effect Polar Chromosome Segregation in Sporulating Bacillus Subtilis

Molecular Microbiology. Sep, 2003  |  Pubmed ID: 12950914

Sporulating cells of Bacillus subtilis undergo a highly polarized cell division and possess a specialized mechanism to move the oriC region of the chromosome close to the cell pole before septation. DivIVA protein, which localizes to the cell pole, and the Soj and Spo0J proteins, which associate with the chromosome, are part of the mechanism that delivers the chromosome to the cell pole. A sporulation-specific protein, RacA, encodes a third DNA-binding protein, which acts in conjunction with Soj and Spo0J to effect efficient polar chromosome segregation. divIVA mutants and soj racA double mutants have an unexpected phenotype in which specific markers to the left and right of oriC can be captured in the prespore compartment but the central oriC region is efficiently excluded. This 'residual' trapping requires Spo0J protein. We suggest that the Soj RacA DivIVA system is required to extract the oriC region from its position determined by the vegetative chromosome segregation machinery and anchor it to the cell pole.

A Self-seeded, Surfactant-directed Hydrothermal Growth of Single Crystalline Lithium Manganese Oxide Nanobelts from the Commercial Bulky Particles

Chemical Communications (Cambridge, England). Dec, 2003  |  Pubmed ID: 14680236

Single crystalline lithium manganese oxide nanobelts were obtained through a self-seeded, surfactant-directed growth process from the commercial bulky particles under hydrothermal treatment. A possible mechanism was proposed to explain the growth of the nanobelts. This new process could be extended to prepare other one-dimensional nanomaterials such as Se nanorods, Te nanotubes, and MnO2 nanowires.

Mechanisms by Which SCN5A Mutation N1325S Causes Cardiac Arrhythmias and Sudden Death in Vivo

Cardiovascular Research. Feb, 2004  |  Pubmed ID: 14736542

Mutations in the cardiac sodium channel gene SCN5A are responsible for type-3 long QT disease (LQT3). The genesis of cardiac arrhythmias in LQT3 is multifaceted, and the aim of this study was to further explore mechanisms by which SCN5A mutations lead to arrhythmogenesis in vivo.

Identification of an Angiogenic Factor That when Mutated Causes Susceptibility to Klippel-Trenaunay Syndrome

Nature. Feb, 2004  |  Pubmed ID: 14961121

Angiogenic factors are critical to the initiation of angiogenesis and maintenance of the vascular network. Here we use human genetics as an approach to identify an angiogenic factor, VG5Q, and further define two genetic defects of VG5Q in patients with the vascular disease Klippel-Trenaunay syndrome (KTS). One mutation is chromosomal translocation t(5;11), which increases VG5Q transcription. The second is mutation E133K identified in five KTS patients, but not in 200 matched controls. VG5Q protein acts as a potent angiogenic factor in promoting angiogenesis, and suppression of VG5Q expression inhibits vessel formation. E133K is a functional mutation that substantially enhances the angiogenic effect of VG5Q. VG5Q shows strong expression in blood vessels and is secreted as vessel formation is initiated. VG5Q can bind to endothelial cells and promote cell proliferation, suggesting that it may act in an autocrine fashion. We also demonstrate a direct interaction of VG5Q with another secreted angiogenic factor, TWEAK (also known as TNFSF12). These results define VG5Q as an angiogenic factor, establish VG5Q as a susceptibility gene for KTS, and show that increased angiogenesis is a molecular pathogenic mechanism of KTS.

A Simple and General Method for the Synthesis of Multicomponent Na2V6O16.3H2O Single-crystal Nanobelts

Journal of the American Chemical Society. Mar, 2004  |  Pubmed ID: 15025459

Multicomponent Na2V6O16.3H2O (barnesite) single-crystalline nanobelts were synthesized by a direct reaction-crystallization growth of bulk V2O5 and NaF powders under hydrothermal treatment without using any templates or catalysts. This new strategy could be extended to prepare other one-dimensional multicomponent nanomaterials including ammonium, alkali-metal or alkali-earth metal vanadium oxide bronzes and other transition metal oxyfluorides. This is an efficient and mild solution method with clear advantages over the traditional high-temperature approach for the large-scale production of 1D multicomponent nanomaterials. The applicability of this approach toward the preparation of other inorganic systems, such as tungstates and molybdates, will be explored.

A Susceptibility Locus at Chromosome 3p21 Linked to Familial Nasopharyngeal Carcinoma

Cancer Research. Mar, 2004  |  Pubmed ID: 15026332

Nasopharyngeal carcinoma (NPC) poses one of the serious health problems in southern Chinese, with an incidence rate ranging from 15 to 50/100,000. Chromosome translocation t(1;3) and frequent loss of heterogeneity on short arms of chromosome 3 and 9 have been reported to be associated with NPC, and a genome-wide scan identified an NPC susceptibility locus on chromosome 4p15.1-q12 recently. In our study, we collected samples from 18 families at high risk of NPC from the Hunan province in southern China, genotyped with a panel of polymorphic markers on short arms of chromosomes 3, 9, and 4p15.1-q12. A locus on 3p21 was identified to link to NPC with a maximum logarithm of odds for linkage score of 4.18. Fine mapping located the locus to a 13.6-cM region on 3p21.31-21.2, where a tumor suppressor gene cluster resided. Our findings identified a novel locus for NPC and provided a map location for susceptibility genes candidates. In contrast to a recent study, no significant evidence for NPC linkage to chromosomes 4 and 9 was observed.

Structure and Segregation of the Bacterial Nucleoid

Current Opinion in Genetics & Development. Apr, 2004  |  Pubmed ID: 15196458

In bacteria, chromosome segregation and DNA replication occur concurrently and there is no clear equivalent of a eukaryote mitotic spindle. Chromosome segregation can be viewed as a two-step process. As the first step, the origin of replication regions are segregated actively, probably by a mechanism involving an as yet unidentified motor protein or proteins, and held in position. The second step is the separation and migration of the rest of the chromosome probably driven by forces generated from various cellular processes such as DNA replication, transcription and transertion.

Coordination of Cell Division and Chromosome Segregation by a Nucleoid Occlusion Protein in Bacillus Subtilis

Cell. Jun, 2004  |  Pubmed ID: 15210112

A range of genetical and physiological experiments have established that diverse bacterial cells possess a function called nucleoid occlusion, which acts to prevent cell division in the vicinity of the nucleoid. We have identified a specific effector of nucleoid occlusion in Bacillus subtilis, Noc (YyaA), as an inhibitor of division that is also a nonspecific DNA binding protein. Under various conditions in which the cell cycle is perturbed, Noc prevents the division machinery from assembling in the vicinity of the nucleoid. Unexpectedly, cells lacking both Noc and the Min system (which prevents division close to the cell poles) are blocked for division, apparently because they establish multiple nonproductive accumulations of division proteins. The results help to explain how B. subtilis specifies the division site under a range of conditions and how it avoids catastrophic breakage of the chromosome by division through the nucleoid.

A General Solution-phase Approach to Oriented Nanostructured Films of Metal Chalcogenides on Metal Foils: the Case of Nickel Sulfide

Journal of the American Chemical Society. Jul, 2004  |  Pubmed ID: 15225043

Oriented films of nickel sulfide nanostructures, ranging from hierarchical dendrites to nanobelts and nanorods, were hydrothermally grown on Ni foils. This approach has proven to be a general method for preparing nanostructured metal chalcogenides films on corresponding metal foils.

A Novel Voltammetric Method for the Direct Determination of Copper in Complex Environmental Samples

Analytical Sciences : the International Journal of the Japan Society for Analytical Chemistry. Jul, 2004  |  Pubmed ID: 15293398

A novel voltammetry with a modified gold electrode for the direct determination of copper in environmental samples, without any pretreatment, is proposed in this paper. A porous disorganized monolayer was formed on the surface of the gold electrode by the self-assembly of mercaptoacetic acid (MAA), which could selectively permeate small molecules. Subtractive square wave anodic stripping voltammetry (SASV) was applied to determine copper, in which the underpotential deposition (UPD) of copper was used as the deposition step. The linear range was from 8 x 10(-7) to 1 x l0(-5) mol l(-1) by the modified electrode in the presence of human serum albumin, and the determination was not interfered with common metal ions. Copper in a real environmental sample was successfully detected.

[Effect of Grazing on Grassland Under Protective Plantation in the Ecotone Between Agriculture and Animal Husbandry or Songnen Plain]

Ying Yong Sheng Tai Xue Bao = The Journal of Applied Ecology / Zhongguo Sheng Tai Xue Xue Hui, Zhongguo Ke Xue Yuan Shenyang Ying Yong Sheng Tai Yan Jiu Suo Zhu Ban. May, 2004  |  Pubmed ID: 15320396

Based on the current special position that grassland under protective plantation is one of the most important grazing spaces of the ecotone between agriculture and animal husbandry in Songnen plain, an experiment was conducted to investigate the effect of grazing on grassland under protective plantation. The results showed that no-grazing grassland in the grassland under protective plantation was seriously degenerated, but light and moderate grazing could stimulate the growth of grass and the product and quality of grassland. The index of grassland quality (IGQ) of no-grazing grassland was the lowest (15.51), attributing to serious degradation, while that of light grazing grassland was the highest (86.41), and the IGQ was decreased with increasing grazing intensity. Therefore, in order to stimulate the grass growth of the grassland, fully utilize the leaves of poplar, and increase the available forage resources, light and moderate grazing intensity should be advocated, but no-grazing and extreme grazing should be avoided.

[Amelioration of Secondary Bare Alkali-saline Patches in Songnen Plain Through Inserting Cornstalk]

Ying Yong Sheng Tai Xue Bao = The Journal of Applied Ecology / Zhongguo Sheng Tai Xue Xue Hui, Zhongguo Ke Xue Yuan Shenyang Ying Yong Sheng Tai Yan Jiu Suo Zhu Ban. Jun, 2004  |  Pubmed ID: 15362617

Based on the field experiment on Songnen grassland, a new method was established to ameliorate the secondary bare alkali-saline patches (SAP) through inserting cornstalk. The experiment was rested on the assumption that through inserting cornstalk in the secondary bare alkali-saline patches (SAP) to retain seeds moving over its surface, the necessary seed source could be gained; and these seeds should be able to germinate and survive successfully on the cornstalk itself or in its neighborhood, where should be more fit to grow than other sites in SAP, due to the decomposition of cornstalk and its special role, so that, the aim to restore vegetation of SAP could be achieved at a pretty low cost and rapid speed. The results showed that the seed bank in soil was increased significantly, owing to the inserted cornstalk and its operating processes. The seed number in ameliorated soil was 4020.0 +/- 1773.6 seeds x m(-2), while that in the secondary bare alkali-saline patches (SAP) was only 10.0 +/- 31.6 seeds x m(-2). Although the soil chemical and physical characters in ameliorated zone were improved to some extent, the overall situation of soil was still bad for plant growth, as the pH, soluble saline ion and organic matter were concerned. Most of Chloris virgata grew around or on the cornstalk, the plants around each cornstalk being 3.9 +/- 2.2, and the total being 48.64 +/- 38.72 g x m(-2). Therefore, this method demanded a few resources, and needed simple technology and low cost, which is potentially deserved to popularize.

Facile Fabrication and Characterization of Hierarchically Porous Calcium Carbonate Microspheres

Chemical Communications (Cambridge, England). Nov, 2004  |  Pubmed ID: 15514792

Higher-order porous calcite microspheres exhibiting high specific surface areas, unusual morphologies and textures were fabricated by a simple precipitation reaction of CaCO3 in the presence of PSMA as a crystal modifier.

[Comparison of Clonal Architecture Between Two Divergent Leymus Chinensis Types in Songnen Grassland]

Ying Yong Sheng Tai Xue Bao = The Journal of Applied Ecology / Zhongguo Sheng Tai Xue Xue Hui, Zhongguo Ke Xue Yuan Shenyang Ying Yong Sheng Tai Yan Jiu Suo Zhu Ban. Dec, 2004  |  Pubmed ID: 15825463

This paper studied the clonal architecture of two divergent Leymus chinensis types (grey-green type and yellow-green type) in Songnen grassland, and compared their internode length, spacer length, interbranching length, interbranching angle, and ramet population density and height under the same habitat. The results showed that there was no significant difference in these clonal characteristics except spacer length and ramet population density between the two types of L. chinensis, and yellow-green type, with less spacer length and more ramet density than grey-green type, should be more adaptable to the resourceful habitat. Moreover, the V-indices of the clonal architecture of two divergent L. chinensis types were all close to 1, and the difference was not significant. Therefore, both of the two types belonged to typical guerilla clonal plant.

A 3-D Noninterpenetrating Diamondoid Network of a Decanuclear Copper(I) Complex

Inorganic Chemistry. May, 2005  |  Pubmed ID: 15877417

The solvothermal reaction of CuCl(2).2H(2)O with pyridine-4-thiol and ethanol yielded a novel photoluminescent 3-D polymeric complex with an interesting decorated diamondoid network that is constructed of decanuclear copper(I) cluster units and mu(4)-Cl ligands. The in situ generation of CuSO(4).5H(2)O implies the spontaneous occurrence of desulfurization and redox reactions in the present system.

Diversity and Redundancy in Bacterial Chromosome Segregation Mechanisms

Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences. Mar, 2005  |  Pubmed ID: 15897175

Bacterial cells are much smaller and have a much simpler overall structure and organization than eukaryotes. Several prominent differences in cell organization are relevant to the mechanisms of chromosome segregation, particularly the lack of an overt chromosome condensation/decondensation cycle and the lack of a microtubule-based spindle. Although bacterial chromosomes have a rather dispersed appearance, they nevertheless have an underlying high level of spatial organization. During the DNA replication cycle, early replicated (oriC) regions are localized towards the cell poles, whereas the late replicated terminus (terC) region is medially located. This spatial organization is thought to be driven by an active segregation mechanism that separates the sister chromosomes continuously as replication proceeds. Comparisons of various well-characterized bacteria suggest that the mechanisms of chromosome segregation are likely to be diverse, and that in many bacteria, multiple overlapping mechanisms may contribute to efficient segregation. One system in which the molecular mechanisms of chromosome segregation are beginning to be elucidated is that of sporulating cells of Bacillus subtilis. The key components of this system have been identified, and their functions are understood, in outline. Although this system appears to be specialized, most of the functions are conserved widely throughout the bacteria.

Cx31 is Assembled and Trafficked to Cell Surface by ER-Golgi Pathway and Degraded by Proteasomal or Lysosomal Pathways

Cell Research. Jun, 2005  |  Pubmed ID: 15987604

Gap junctions, consisting of connexins, allow the exchange of small molecules (less than 1 KD) between adjacent cells, thus providing a mechanism for synchronizing the responses of groups of cells to environmental stimuli. Connexin 31 is a member of the connexin family. Mutations on connexin 31 are associated with erythrokeratodermia variabilis, hearing impairment and peripheral neuropathy. However, the pathological mechanism for connexin 31 mutants in these diseases are still unknown. In this study, we analyzed the assembly, trafficking and metabolism of connexin 31 in HeLa cells stably expressing connexin 31. Calcein transfer assay showed that calcein transfer was inhibited when cells were treated with Brefeldin A or cytochalasin D, but not when treated with nocodazole or a-glycyrrhetinic acid, suggesting that Golgi apparatus and actin filaments, but not microtubules, are crucial to the trafficking and assembly of connexin 31, as well as the formation of gap junction intercellular communication by connexin 31. Additionally, a-glycyrrhetinic acid did not effectively inhibit gap junctional intercellular communication formed by connexin 31. Pulse-chase assay revealed that connexin 31 had a half-life of about 6 h. Moreover, Western blotting and fluorescent staining demonstrated that in HeLa cells stably expressing connexin 31, the amount of connexin 31 was significantly increased after these cells were treated with proteasomal or lysosomal inhibitors. These findings indicate that connexin 31 was rapidly renewed, and possibly degraded by both proteasomal and lysosomal pathways.

[Study on Prevention of Catheter Associated Urinary Tract Infection by Using JUS Long-acting Antibacterial Material]

Zhonghua Nan Ke Xue = National Journal of Andrology. Aug, 2005  |  Pubmed ID: 16138575

To observe the effect of reducing the incidence of CAUTI by spraying the long-acting antibacterial material JUS on the surface of catheter and urethral orifice.

A General in Situ Hydrothermal Rolling-up Formation of One-dimensional, Single-crystalline Lead Telluride Nanostructures

Small (Weinheim an Der Bergstrasse, Germany). Mar, 2005  |  Pubmed ID: 17193455

In this study we demonstrate that one-dimensional (1D) nanostructured lead telluride (PbTe) can be synthesized in a hydrothermal reaction between lead foil and tellurium powder. The resulting materials were characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The formation of the 1D structure can be explained by an in situ hydrothermal rolling-up mechanism whereby PbTe is formed hydrothermally and deposited on the lead substrate. The lead underneath the PbTe layer is then selectively etched by a cetyltrimethylammonium bromide solution, thus allowing the PbTe to roll up into 1D structures. This method can be extended to prepare other 1D tellurides, including CdTe, Cu(2)Te, and Ag(2)Te.

A Mesoporous Pt/TiO2 Nanoarchitecture with Catalytic and Photocatalytic Functions

Chemistry (Weinheim an Der Bergstrasse, Germany). May, 2005  |  Pubmed ID: 15761909

A novel metal/semiconductor nanocomposite with catalytic and photocatalytic functions has been prepared. The new material consists of highly dispersed platinum (Pt) nanoparticles embedded in a cubic mesoporous nanocrystalline anatase (meso-nc-TiO2) thin film. The porous thin film possesses a narrow pore-size distribution and a large surface area. The diameter of the Pt cluster can be controlled to below 5 nm, and the high dispersion of these clusters gives rise to catalytic activity for the oxidation of carbon monoxide, an important reaction for automobile exhaust treatment. This novel ordered mesoporous Pt/TiO2 nanoarchitecture is also a promising photochemical material, as demonstrated by the photo-driven killing of Micrococcus lylae cells on the film.

Elevated Telomere-telomere Recombination in WRN-deficient, Telomere Dysfunctional Cells Promotes Escape from Senescence and Engagement of the ALT Pathway

Genes & Development. Nov, 2005  |  Pubmed ID: 16264192

Werner Syndrome (WS) is characterized by premature aging, genomic instability, and cancer. The combined impact of WRN helicase deficiency and limiting telomere reserves is central to disease pathogenesis. Here, we report that cells doubly deficient for telomerase and WRN helicase show chromosomal aberrations and elevated recombination rates between telomeres of sister chromatids. Somatic reconstitution of WRN function, but not a WRN helicase-deficient mutant, abolished telomere sister chromatid exchange (T-SCE), indicating that WRN normally represses T-SCEs. Elevated T-SCE was associated with greater immortalization potential and resultant tumors maintained telomeres via the alternative lengthening of telomere (ALT) pathway. We propose that the increased incidence of chromosomal instability and cancer in WS relates in part to aberrant recombinations between sister chromatids at telomeres, which facilitates the activation of ALT and engenders cancer-relevant chromosomal aberrations and tumor formation.

Uptake of a Fluorescent Deoxyglucose Analog (2-NBDG) in Tumor Cells

Molecular Imaging and Biology : MIB : the Official Publication of the Academy of Molecular Imaging. Nov-Dec, 2005  |  Pubmed ID: 16284704

A new fluorescent analog of D -glucose was recently developed by [Yoshioka K, Takahashi H, Homma T, Sato M, Ki Bong O, Nemoto Y, Matsuoka H (1996) A novel fluorescent derivative of glucose applicable to the assessment of glucose uptake activity of Escherichia coli. Biochim Biophys Acta 1289:5-9] and shown to be transported into normal cells. The purpose of this preliminary study was to assess the use of this fluorescent 2-deoxyglucose analog, 2-[N-(7-nitrobenz-2-oxa-1,3-diaxol-4-yl)amino]-2-deoxyglucose (2-NBDG), as a sensitive probe for monitoring glucose uptake into malignant tumor cells.

[Study on the Comet-tail System of 12C16O+ in the Near-infrared Region]

Guang Pu Xue Yu Guang Pu Fen Xi = Guang Pu. Aug, 2005  |  Pubmed ID: 16329493

The molecular cation CO+ is a very important transient molecular radical, and the spectra of the ion has been investigated by numerous researchers. Optical-heterodyne-magnetic-rotation-enhanced velocity modulation spectroscopy(OH-MR-VMS) was employed to measure the comet-tail system (A2 pi(i)-X2 sigma+) of 12C16O+ molecular ion. The vibrational rotation absorption spectra wereobserved in the near-infrared region, including three bands of (0, 3), (1, 4) and (3, 6). A set of precise molecular constants for the A2 pi(i) (v' = 0, 1, 3) were determined using the least-squares fit. This experiment has further proved that OH-MR-VMS is very valuable in measuring absorption spectra of molecular ions.

Systematic Localisation of Proteins Fused to the Green Fluorescent Protein in Bacillus Subtilis: Identification of New Proteins at the DNA Replication Factory

Proteomics. Apr, 2006  |  Pubmed ID: 16479537

Construction and microscopic imaging of protein fusions to green fluorescent protein (GFP) have revolutionised our understanding of bacterial structure and function. We have undertaken a systematic study of the localisation of over 100 Bacillus subtilis proteins, following the development of high-throughput construction and analysis procedures. We focused on proteins linked in various ways to the DNA replication machinery, as well as on proteins exemplifying a range of other cellular functions and structures. The results validate the approach as a way of obtaining systematic protein localisation information. They also provide a range of novel biological insights, particularly through the identification of a number of proteins not previously known to be associated with the DNA replication factory.

Proliferation and Pluripotency Potential of Ectomesenchymal Cells Derived from First Branchial Arch

Cell Proliferation. Apr, 2006  |  Pubmed ID: 16542344

Cranial neural crest-derived ectomesenchymal cells are multipotential progenitors that contribute to various tissue types during embryogenesis. Their potential to be expanded in culture as a monolayer and to be induced into different cell lineages in vitro has not been previously reported in detail. In this study, the ectomesenchymal cells in the first branchial arch were enzymatically isolated from the mandibular processes of BALB/c mice and were maintained in an intact state in a medium containing leukaemia inhibitory factor. Here, we first evaluated the proliferative activity of the cells after the third passage, using bromodeoxyuridine labelling and in situ hybridization of telomerase mRNA. Positive staining for expression of HNK-1, S-100 and vimentin confirmed that the population of stem cells originated from the ectomesenchyme, which did not express cytokeratin. Then we investigated the molecular and cellular characteristics of the ectomesenchymal cells during their differentiation towards neurogenic, endothelial, myogenic and odontogenic lineages. Expression of multiple lineage-specific genes and proteins was detected by utilizing a range of molecular and biochemical approaches when the cells were transferred to inductive medium. Histological and immunohistochemical analysis of the induced cells at various intervals indicated obvious phenotypic alteration and presence of specific proteins for the differentiated lineages, for example nestin, factor VIII, alpha-SMA and dentin sialophosphoprotein (DSPP), respectively. Correlatively, results of reverse transcription-PCR corroborated at mRNA level the expression of the characteristic molecules during differentiation. Therefore, it is suggested that the ectomesenchymal cells derived from the first branchial arch may represent a novel source of multipotential stem cells capable of undergoing expansion and variant differentiation in vitro.

Deletion of Presenilin 1 Hydrophilic Loop Sequence Leads to Impaired Gamma-secretase Activity and Exacerbated Amyloid Pathology

The Journal of Neuroscience : the Official Journal of the Society for Neuroscience. Apr, 2006  |  Pubmed ID: 16597739

gamma-Secretase processing of the amyloid precursor protein (APP) generates Abeta40 and Abeta42, peptides that constitute the principal components of the beta-amyloid plaque pathology of Alzheimer's disease (AD). The gamma-secretase activity is executed by a high-molecular-weight complex of which presenilin 1 (PS1) is an essential component. PS1 is a multi-pass membrane protein, and the large hydrophilic loop domain between transmembrane domains 6 and 7 has been shown to interact with various proteins. To determine the physiological function of the loop domain, we created a strain of PS1 knock-in mice in which the exon 10, which encodes most of the hydrophilic loop sequence, was deleted from the endogenous PS1 gene. We report here that the homozygous exon 10-deleted mice are viable but exhibit drastically reduced gamma-secretase cleavage at the Abeta40, but not the Abeta42, site. Surprisingly, this reduction of Abeta40 is associated with exacerbated plaque pathology when expressed on APP transgenic background. Thus, the PS1 loop plays a regulatory role in gamma-secretase processing, and decreased Abeta40, not increased Abeta42 is likely the cause for the accelerated plaque deposition in these animals. Our finding supports a protective role of Abeta40 against amyloid pathology and raises the possibility that impaired gamma-secretase activity could be the basis for AD pathogenesis in general.

ZrO2-modified Mesoporous Nanocrystalline TiO2-xNx As Efficient Visible Light Photocatalysts

Environmental Science & Technology. Apr, 2006  |  Pubmed ID: 16646476

Mesoporous nanocrystalline TiO2-xNx and TiO2-xNx/ZrO2 visible-light photocatalysts have been prepared by a sol-gel method. The photocatalysts were characterized by XRD, N2 adsorption-desorption, TEM, XPS, UV/Vis, and IR spectroscopy. The photocatalytic activity of the samples was evaluated by the decomposition of ethylene in air under visible light (lambda > 450 nm) illumination. Results revealed that nitrogen was doped into the lattice of TiO2 by the thermal treatment of NH3-adsorbed TiO2 hydrous gels, converting the TiO2 into a visible-light responsive catalyst. The introduction of ZrO2 into TiO2-xNx considerably inhibits the undesirable crystal growth during calcination. Consequently, the ZrO2-modified TiO2-xNx displays higher porosity, higher specific surface area, and an improved thermal stability over the corresponding unmodified TiO2-xNx samples.

Pluripotency Potential of Human Adipose-derived Stem Cells Marked with Exogenous Green Fluorescent Protein

Molecular and Cellular Biochemistry. Oct, 2006  |  Pubmed ID: 16718363

Musculoskeletal tissues regeneration requires rapid expansion of seeding cells both in vitro and in vivo while maintaining their multilineage differentiation ability. Human adipose-derived stem cells (ASCs) are considered to contain multipotent mesenchymal stem cells. Monolayer cultures of human ASCs were isolated from human lipoaspirates and passaged 3 times and then infected with replication-incompetent adenoviral vectors carrying green fluorescent protein (Ad/GFP) genes. Then, Ad/GFP infected human ASCs were transferred to osteogenic, chondrogenic, adipogenic, and myogenic medium. The morphological characterization of induced cells was observed using phase-contrast microscopy and fluorescence microscopy. The expression of marker proteins or genes was measured by immunocytochemical and RT-PCR analysis. Osteopontin (OPN), and osteocalcin (OCN) were positive in osteogenic lineages, aggrecan and SOX9 were positive in chondrogenic ones, peroxisome proliferator-activated receptor (PPAR-gamma2) and lipoprotein lipase (LPL) were positive in adipogenic ones, and myogenin and myod1 was positive in myogenic ones. At the same time, the results of fluorescence microscopic imaging proved that the high level of GFP expression during ASCs differentiation maintained stable nearly 2 months. So the exogenous GFP and multilineage potential of human ASCs had no severe influences on each other. Since the human ASCs can be easily obtained and abundant, it is proposed that they may be promising candidate cells for further studies on tissue engineering. Imaging with expression of GFP facilitates the research on ASCs physiological behavior and application in tissue engineering during differentiation both in vitro and in vivo.

Low-potential Nicotinamide Adenine Dinucleotide Detection at a Glassy Carbon Electrode Modified with Toluidine Blue O Functionalized Multiwall Carbon Nanotubes

Analytical Sciences : the International Journal of the Japan Society for Analytical Chemistry. Mar, 2006  |  Pubmed ID: 16733311

The toluidine blue O (TBO) functionalized multiwall carbon nanotubes (MWNTs) nanomaterials (TBO-MWNTs) were prepared by assembling TBO onto the surface of a MWNTs modified glassy carbon (GC) electrode. Also TBO-MWNTs modified GC electrodes exhibiting a strong and stable electrocatalytic response toward beta-nicotinamide adenine dinucleotide (NADH) were described. Compared with a bare GC electrode, the TBO-MWNTs modified GC electrodes could decrease the oxidization overpotential of NADH by 730 mV, with a peak current at 0.0 V, since there was a positively synergistic electrocatalytic effect between the MWNTs and TBO toward NADH. Furthermore, the TBO-MWNTs modified GC electrodes had perfect performances, such as a low detection limit (down to 0.5 microM), being very stable (the current diminutions is lower than 6% in a period over 35 min), a fast response (within 3 s), and a wide linear range (from 2.0 microM to 3.5 mM). Such an ability of TBO-MWNTs to promote the NADH electron-transfer reaction suggests great promise for dehydrogenase-based amperometric biosensors.

Pot1 Deficiency Initiates DNA Damage Checkpoint Activation and Aberrant Homologous Recombination at Telomeres

Cell. Jul, 2006  |  Pubmed ID: 16839876

The terminal t-loop structure adopted by mammalian telomeres is thought to prevent telomeres from being recognized as double-stranded DNA breaks by sequestering the 3' single-stranded G-rich overhang from exposure to the DNA damage machinery. The POT1 (protection of telomeres) protein binds the single-stranded overhang and is required for both chromosomal end protection and telomere length regulation. The mouse genome contains two POT1 orthologs, Pot1a and Pot1b. Here we show that conditional deletion of Pot1a elicits a DNA damage response at telomeres, resulting in p53-dependent replicative senescence. Pot1a-deficient cells exhibit overall telomere length and 3' overhang elongation as well as aberrant homologous recombination (HR) at telomeres, manifested as increased telomere sister chromatid exchanges and formation of telomere circles. Telomeric HR following Pot1a loss requires NBS1. Pot1a deletion also results in chromosomal instability. Our results suggest that POT1a is crucial for the maintenance of both telomere integrity and overall genomic stability.

Initiation of Antiretroviral Therapy During Chronic SIV Infection Leads to Rapid Reduction in Viral Loads and the Level of T-cell Immune Response

Journal of Medical Primatology. Aug, 2006  |  Pubmed ID: 16872283

In the present era of increasing resistance of human immunodeficiency virus (HIV) to antiviral drugs, exploration of adjunct therapies directed at immune responses in combination with antiretroviral drugs may be of value for the treatment of acquired immunodeficiency syndrome. In this study, we designed a model for immune therapy using SIVmac251 infection in rhesus macaques. We explored the outcomes of primary infection on viral loads and the resulting T-cell immune responses in primates. The SIV-infected rhesus macaque model exhibited features similar to those observed in HIV-1 infection of humans. Major histocompatibility complex (MHC) segregation with viral loads were found to associate with viral containment and hence the duration of the disease-free latency period. Thus a better understanding of the relative roles of MHC class I allele in control of viral replication may provide important information for prophylactic or therapeutic vaccine designs. Mamu-A01 is significantly associated with higher immune response and control of viral replication. This allele is frequent in rhesus macaques of Indian origin (22%). Interestingly, Mamu-B01 (26% animals) was associated with lower immune responses and higher viral loads. Another allele, A08 was also predominantly present in 37% of the animals in this study. We observed higher viral replication in individual SIV-infected rhesus monkeys that did not demonstrate strong cellular immune responses. The results are important for understanding SIV disease progression in different MHC Mamu alleles and also for improving the interpretation and quality of pre-clinical studies in rhesus monkeys.

Study on Chromium (VI) Reduction Kinetics by Pseudomonas Aeruginosa Using a Combined System of Acoustic Wave Impedance Analyzer and UV-vis Spectrophotometer

Current Microbiology. Sep, 2006  |  Pubmed ID: 16874546

A novel system combining acoustic wave impedance (AWI) analyzer with UV-vis spectrophotometer was developed for the study of chromium (VI) reduction kinetics by Pseudomonas aeruginosa. AWI gave information about the growth of Pseudomonas aeruginosa, and UV-vis spectrophotometer gave information about the concentration of chromium (VI) simultaneously. A combined system response model, for chromium (VI) reduction kinetics at lower initial chromium (VI) concentrations, was derived and proved based on the novel system. Taking into account the effect of bacterial growth on chromium (VI) reduction, the new model successfully simulated chromium (VI) bioremediation process. By fitting chromium (VI) reduction data toward the derived model, the kinetic parameters related to the process were obtained. When the concentration of peptone was 10 g L(-1), the half-velocity reduction rate constant K (C) and the maximum specific chromium (VI) reduction rate constant nu(max) were 0.7682 mg chromium (VI) L(-1) and 2.5814 x 10(-12) mg chromium (VI) cells(-1) h(-1), respectively. It was found that the combined system can provide real-time, reliable, and two-dimensional kinetic information, and can be applied to study other biological processes.

Phylogenetic Relationships and Possible Hybrid Origin of Lycoris Species (Amaryllidaceae) Revealed by Its Sequences

Biochemical Genetics. Jun, 2006  |  Pubmed ID: 16933142

To examine interspecific relationships and test the hypothesis of hybrid origin within Lycoris species, this study used data from parsimony analyses with nuclear ITS sequences for 19 taxa representing 14 species of Lycoris and two outgroup taxa. The ITS sequences resolved three infrageneric clades. One clade included L. chinensis, L. longituba, L. longituba var. flava, L. anhuiensis, and L. aurea; the second one consisted of L. sprengeri, L. radiata, L. radiata var. radiata, L. radiata var. pumila, L. haywardii, L. rosea, L. sanguinea var. sanguinea, and L. sanguinea var. koreana; and the third included L. caldwellii, L. straminea, L. albiflora, L. flavescens, and two hybrids. The results strongly support the hypothesis that L. straminea originated from hybridization between L. chinensis and L. radiata var. pumila, and the allotriploid L. caldwellii and L. albiflora derived from hybridization between L. chinensis and L. sprengeri. As nucleotide additivity was observed in the artificial hybrids and several presumed hybrids, the likelihood of hybrid origin of Lycoris species is supported.

Efficient Decomposition of Benzene over a Beta-Ga2O3 Photocatalyst Under Ambient Conditions

Environmental Science & Technology. Sep, 2006  |  Pubmed ID: 17007143

A porous beta-Ga2O3 photocatalyst has been successfully prepared. The photocatalyst was characterized by XRD, N2 adsorption-desorption, TEM, UV/vis, and FTIR techniques. The photocatalytic activity of the sample was evaluated by the decomposition of benzene in air under UV light illumination and was compared with that of the commercial titania (Degussa P25) and Pt/P25. Results revealed that the synthesized Ga2O3 was porous beta-Ga2O3 and was highly photoactive for mineralizing benzene and its derivatives (e.g., toluene and ethylbenzene) to CO2 under ambient conditions. The photocatalytic conversion of benzene over beta-Ga2O3 was about 1 order of magnitude higher than that over P25, and no obvious deactivation of beta-Ga2O3 was observed during the prolonged operation of 80 h. The high activity and long-term stability of the Ga2O3 have been ascribed to its stronger oxidative capability and higher specific surface area in comparison with P25.

[A Study on Transfection of Green Fluorescence Protein Gene into Human Adipose Stromal Cells in Vitro]

Sichuan Da Xue Xue Bao. Yi Xue Ban = Journal of Sichuan University. Medical Science Edition. Sep, 2006  |  Pubmed ID: 17037731

To make a comparison on the efficiency of two methods for transfecting Green Fluorescence Protein gene into human adipose tissue-derived stromal cells, and to study the biological properties and multipotential differentiation of gene-transfected cells.

Rhesus Macaques with High Levels of Vaccine Induced IFN-gamma Producing Cells Better Control Viral Set-point Following Challenge with SIV239

Vaccine. May, 2006  |  Pubmed ID: 16185790

HIV-1 specific cellular immune responses play a significant part in controlling HIV-1 viral replication and are an important component of an HIV-1 vaccine induced immune response. We reported earlier that recombinant DNA vaccine delivered intramuscularly, and recombinant Listeria monocytogenes, delivered orally induced CD8+ and CD4+ T cell immune responses in rhesus macaques and that this vaccine protocol showed partial protection against an SIV239 challenge. In this paper, we have analyzed the SIV antigen-specific immune responses at the time of challenge and during the subsequent infection course. We find that the immune status of the animals, as measured by the frequency of antigen-specific IFN-gamma secreting peripheral blood mononuclear cells, at the time of challenge correlates more strongly with viral loads at set point than peak viral loads. The correlation between the immune response and viral load was strongest early, as viral set-point was just being established and disintegrates overtime. This study demonstrates the cellular immune response to SIV at the time of challenge of a nonhuman primate is able to impact on viral set-point following SIV239 challenge. Further, this study demonstrates that as virus replicates the T cell immune response to SIV antigens induced by the vaccine is modulated by antigen encountered by immune cells during viral replication.

[The Gene Expression Patterns of Bone-marrow Mesenchymal Stem Cells Under Different Osteogenic Induction]

Sichuan Da Xue Xue Bao. Yi Xue Ban = Journal of Sichuan University. Medical Science Edition. Nov, 2006  |  Pubmed ID: 17236579

To investigate the molecular mechanism of osteogenetic differentiation of bone-marrow mesenchymal stem cells (BMSCs) and the probability using the BMSCs to gene therapy for bone fractures.

Characterization of Ectomesenchymal Cells Isolated from the First Branchial Arch During Multilineage Differentiation

Cells, Tissues, Organs. 2006  |  Pubmed ID: 17108683

Ectomesenchymal cells isolated from the first branchial arch have the potential to differentiate into a variety of cell lineages both in vitro and in vivo. This study was aimed to confirm the plasticity of multilineage differentiation with molecular and cellular characterization. Monolayer cultures of ectomesenchymal cells harvested from the first branchial arch primordia in embryonic day 9.5 BALB/c mice were passaged 3 times before analysis. Staining with antibodies against S-100, p75 and vimentin suggested that the population of stem cells originated from ectomesenchyme, with few contaminating cells stained for cytokeratin. Then, cells were transferred to adipogenic, osteogenic, chondrogenic and odontogenic media. The initiation of controlled differentiation was determined with histological assays, and the expression of tissue-specific genes was detected using immunocytochemical staining and reverse transcription polymerase chain reaction. The adipogenic ectomesenchymal cells showed accumulation of lipid vacuoles and expression of lipoprotein lipase and peroxisome proliferator-activated receptor gamma(2). Following osteoinduction, the fibroblast-like cells became cuboidal and formed mineralized nodules. In addition, the expression of mRNA encoding osteocalcin and osteopontin proved osteogenesis at the molecular level. Chondrogenic lineage expressed collagen type II, aggrecan and Sox9 with a low level of collagen type I in monolayer culture. Odontogenesis was determined by dentin sialophosphoprotein, collagen type I and dentin matrix protein 1 expression. Therefore, we have demonstrated that ectomesenchymal cells from the first branchial arch are capable of extensive multilineage differentiation in vitro, controllable by the culture environment. This makes them a relevant and valuable source of stem cells for research of craniofacial development and tissue engineering of restoration.

Direct Electrochemistry and Electrocatalysis of Hemoglobin Entrapped in Semi-interpenetrating Polymer Network Hydrogel Based on Polyacrylamide and Chitosan

Bioelectrochemistry (Amsterdam, Netherlands). Nov, 2007  |  Pubmed ID: 17398166

Semi-interpenetrating polymer network (semi-IPN) hydrogel based on polyacrylamide (PAM) and chitosan was prepared to immobilize redox protein hemoglobin (Hb). The Hb-PAM-chitosan hydrogel film obtained has been investigated by scanning electron microscopy (SEM) and UV-VIS spectroscopy. UV-VIS spectroscopy showed that Hb kept its secondary structure similar to its native state in the Hb-PAM-chitosan hydrogel film. Cyclic voltammogram of Hb-PAM-chitosan film-modified glass carbon (GC) electrode showed a pair of well-defined and quasi-reversible redox peaks for Hb Fe(III)/Fe(II), indicating that direct electron transfer between Hb and GC electrode occurred. The electron-transfer rate constant was about 5.51 s(-1) in pH 7.0 buffers, and the formal potential (E degrees ') was -0.324 V (vs. SCE). The dependence of E degrees ' on solution pH indicated that one-proton transfer was coupled to each electron transfer in the direct electron-transfer reaction. Additionally, Hb in the semi-IPN hydrogel film retained its bioactivity and showed excellent electrocatalytic activity toward H(2)O(2). The electrocatalytic current values were linear with increasing concentration of H(2)O(2) in a wide range of 5-420 microM. The unique semi-IPN hydrogel would have wide potential applications in direct electrochemistry, biosensors and biocatalysis.

Induction of High STAT1 Expression in Transgenic Mice with LQTS and Heart Failure

Biochemical and Biophysical Research Communications. Jun, 2007  |  Pubmed ID: 17490620

Cardiac-specific expression of the N1325S mutation of SCN5A in transgenic mouse hearts (TG-NS) resulted in long QT syndrome (LQTS), ventricular arrhythmias (VT), and heart failure. In this study we carried out oligonucleotide mircoarray analysis to identify genes that are differentially expressed in the TG-NS mouse hearts. We identified 33 genes in five different functional groups that showed differential expression. None of the 33 genes are ion channel genes. STAT1, which encodes a transcription factor involved in apoptosis and interferon response, showed the most significant difference of expression between TG-NS and control mice (a nearly 10-fold increase in expression, P=4x10(-6)). The results were further confirmed by quantitative real-time PCR and Western blot analyses. Accordingly, many interferon response genes also showed differential expression in TG-NS hearts. This study represents the first microarray analysis for LQTS and implicates STAT1 in the pathogenesis and progression of LQTS and heart failure.

Assessment of Hepatic Functional Reserve by Cirrhosis Grading and Liver Volume Measurement Using CT

World Journal of Gastroenterology : WJG. Aug, 2007  |  Pubmed ID: 17663509

To explore a method for quantitative assessment of hepatic functional reserve by combining computed tomography (CT) volumetry with CT grading of liver cirrhosis before liver resection in patients with hepatocellular carcinoma.

Dual Role of the TRPV4 Channel As a Sensor of Flow and Osmolality in Renal Epithelial Cells

American Journal of Physiology. Renal Physiology. Nov, 2007  |  Pubmed ID: 17699550

Gain/loss of function studies were utilized to assess the potential role of the endogenous vanilloid receptor TRPV4 as a sensor of flow and osmolality in M-1 collecting duct cells (CCD). TRPV4 mRNA and protein were detectable in M-1 cells and stably transfected HEK-293 cells, where the protein occurred as a glycosylated doublet on Western blots. Immunofluorescence imaging demonstrated expression of TRPV4 at the cell membranes of TRPV4-transfected HEK and M-1 cells and at the luminal membrane of mouse kidney CCD. By using intracellular calcium imaging techniques, calcium influx was monitored in cells grown on coverslips. Application of known activators of TRPV4, including 4alpha-PDD and hypotonic medium, induced strong calcium influx in M-1 cells and TRPV4-transfected HEK-293 cells but not in nontransfected cells. Applying increased flow/shear stress in a parallel plate chamber induced calcium influx in both M-1 and TRPV4-transfected HEK cells but not in nontransfected HEK cells. Furthermore, in loss-of-function studies employing small interference (si)RNA knockdown techniques, transfection of both M-1 and TRPV4-transfected HEK cells with siRNA specific for TRPV4, but not an inappropriate siRNA, led to a time-dependent decrease in TRPV4 expression that was accompanied by a loss of stimuli-induced calcium influx to flow and hypotonicity. It is concluded that TRPV4 displays a mechanosensitive nature with activation properties consistent with a molecular sensor of both fluid flow (or shear stress) and osmolality, or a component of a sensor complex, in flow-sensitive renal CCD.

Osteogenic Differentiation of Adipose Derived Stem Cells Promoted by Overexpression of Osterix

Molecular and Cellular Biochemistry. Jul, 2007  |  Pubmed ID: 17206379

Adipose-derived stem cells (ASCs) are considered to be multipotent mesenchymal stem cells that are easily induced to differentiate into functional osteoblasts both in vitro and in vivo. Osterix (Osx) is a zinc finger-containing transcription factor of Sp gene family, which plays important roles in bone development and mineralization. In this study, we hypothesized that overexpression of Osx in murine ASCs would promote their osteogenic differentiation in vitro. A plasmid expressing Osx (pcDNA3.1-Osx) was constructed and applied to transfect monolayers of murine ASCs. Then expression of bone-related genes, nodule formation, proliferation rate, and alkaline phosphatase activity were examined to evaluate the osteogenic potential of ASCs with pcDNA3.1-Osx transfection. Results of RT-PCR and immunohistochemistry showed that pcDNA3.1-Osx transfection enhanced the expression of bone matrix proteins, such as bone sialoprotein, osteocalcin, osteopontin, and Collagen type I in ASCs. At the same time, overexpression of Osx in ASCs enhanced alkaline phosphatase activity and capability to form mineralized nodules, while not inhibited their proliferation rate. These results indicated that pcDNA3.1-Osx transfection promoted the osteogenic differentiation of ASCs, while not affecting their proliferative ability. Since they can be easily isolated and genetically modified, ASCs are hopeful cell sources in the further application of hard tissue engineering.

Ectopic and in Situ Bone Formation of Adipose Tissue-derived Stromal Cells in Biphasic Calcium Phosphate Nanocomposite

Journal of Biomedical Materials Research. Part A. Jun, 2007  |  Pubmed ID: 17236222

Adipose-derived stromal cells (ASCs) have the potential to differentiate into a variety of cell lineages both in vitro and in vivo. A novel biodegradable biphasic calcium phosphate nanocomposite (NanoBCP) comprising beta-tricalcium phosphate matrix and hydroxyl apatite nanofibers is favorable for bone tissue engineering. In this study, ASCs were harvested from Sprague-Dawley (SD) rats and induced to osteogenesis before seeded into porous NanoBCP scaffold. To determine ectopic in vivo osteogenic differentiation, these constructs were implanted in nude mice subcutaneously. Meanwhile, the ability of engineered constructs to stimulate in situ bone repair was assessed in rat critical-size cranial defects. The defects were filled with NanoBCP containing osteogenic ASCs in experimental group; with cell-free NanoBCP in negative controls; and with nothing in blank controls. The retrieved specimens were analyzed with morphological, histological, and molecular methods. Histological analysis of the retrieved specimens from nude mice in experimental group showed obvious ectopic bone formation. There were positive expression of osteopontin (OPN) and osteocalcin (OCN) at RNA and protein level. As for the cranial defects, there was complete repair in experimental group, but only partial repair in negative controls. The radiographs, H&E staining, and Masson's trichrome method showed better bone regeneration at experimental sites. Combining osteogenic ASCs with NanoBCP can lead to formation of ectopic new bone. Furthermore, the approach can also stimulate bone regeneration and repair for the large size bone defects.

[The Formation of Aneurysm of Apex After the Occlusion of Ventricular Septal Defect]

Zhonghua Xin Xue Guan Bing Za Zhi. Apr, 2007  |  Pubmed ID: 17711673

Catena-poly[[dinitratocadmium(II)]bis[mu-bis(2-methyl-1H-imidazol-1-yl)methane-kappa(2)N(3):N(3')]]

Acta Crystallographica. Section C, Crystal Structure Communications. Oct, 2007  |  Pubmed ID: 17917216

The title compound, [Cd(NO(3))(2)(C(9)H(12)N(4))(2)](n), has a one-dimensional double-bridged chain polymer structure with a 16-membered macrometallacyclic tetragonal structural motif. The Cd(II) ion occupies a crystallographic inversion centre and is coordinated by four equatorial N atoms from four distinct bis(2-methylimidazol-1-yl)methane ligands and two apical nitrate O atoms to form a slightly distorted octahedral coordination geometry.

Ectopic Adipogenesis of Preconditioned Adipose-derived Stromal Cells in an Alginate System

Cell and Tissue Research. Dec, 2007  |  Pubmed ID: 17922143

Soft tissue substitutes are increasingly needed in reconstructive and plastic surgery, although difficulties arise when autografts or allografts have to provide long-term satisfactory replacement in soft tissue restoration. Adipose tissue engineering has highlighted the possibility of soft tissue restoration by using regeneration strategies. As few reports exist regarding adipose regeneration with alginate systems mixed with adipose-derived stromal cells (ASCs), the present study has attempted to evaluate the adipogenic differentiation of ASCs isolated from BALB/c mice in vitro and to define the potential of ASCs to form ectopic adipose tissue in an alginate system with subcutaneous implantation in nude mice. After 10 days induction in vitro, prediferentiated ASCs were seeded in an alginate gel system and implanted subcutaneously into the dorsum of nude mice. Adipogenesis of the newly formed tissue at 8 weeks post-implantation was confirmed by oil red O staining, reverse transcription/polymerase chain reaction, and Western blot analysis. This study thus provides evidence that the alginate system has the ability to form ectopic adipose tissue when mixed with predifferentiated ASCs. The results also supply clues for improving adipose tissue engineering and soft tissue defects repair in adults.

Protection Against Simian/human Immunodeficiency Virus (SHIV) 89.6P in Macaques After Coimmunization with SHIV Antigen and IL-15 Plasmid

Proceedings of the National Academy of Sciences of the United States of America. Nov, 2007  |  Pubmed ID: 18000037

The cell-mediated immune profile induced by a recombinant DNA vaccine was assessed in the simian/HIV (SHIV) and macaque model. The vaccine strategy included coimmunization of a DNA-based vaccine alone or in combination with an optimized plasmid encoding macaque IL-15 (pmacIL-15). We observed strong induction of vaccine-specific IFN-gamma-producing CD8(+) and CD4(+) effector T cells in the vaccination groups. Animals were subsequently challenged with 89.6p. The vaccine groups were protected from ongoing infection, and the IL-15 covaccinated group showed a more rapidly controlled infection than the group treated with DNA vaccine alone. Lymphocytes isolated from the group covaccinated with pmacIL-15 had higher cellular proliferative responses than lymphocytes isolated from the macaques that received SHIV DNA alone. Vaccine antigen activation of lymphocytes was also studied for a series of immunological molecules. Although mRNA for IFN-gamma was up-regulated after antigen stimulation, the inflammatory molecules IL-8 and MMP-9 were down-regulated. These observed immune profiles are potentially reflective of the ability of the different groups to control SHIV replication. This study demonstrates that an optimized IL-15 immune adjuvant delivered with a DNA vaccine can impact the cellular immune profile in nonhuman primates and lead to enhanced suppression of viral replication.

Immobilization of Bovine Serum Albumin As a Sensitive Biosensor for the Detection of Trace Lead Ion in Solution by Piezoelectric Quartz Crystal Impedance

Analytical Biochemistry. Jan, 2007  |  Pubmed ID: 17097591

A biosensor based on bovine serum albumin (BSA) for the detection of lead (Pb(2+)) ion was developed and characterized. BSA was immobilized onto a colloidal Au-modified piezoelectric quartz crystal (PQC) as a biosensor for the detection of Pb(2+) ion by piezoelectric quartz crystal impedance (PQCI). Calibration curves for the quantification of Pb(2+) ion showed excellent linearity throughout the concentration range from 1.0 x 10(-7) to 3.0 x 10(-9)mol/L. The interaction between the Pb(2+) ions and the sensor chip is influenced significantly by the pH of the reaction buffer, and the optimal pH for the experiment was 5.4. Under the optimal conditions, the detection limit of 1.0 x 10(-9)mol/L for Pb(2+) was obtained. Kinetic parameters of the Pb(2+)-BSA interactions were also determined by using this chip. The sensor chip could be regenerated for use by dipping in the ethylenediaminetetraacetic acid (EDTA) solution for approximately 2h, and the chip was used to detect Pb(2+) ion for eight times without obvious signal attenuation.

Expression of Pcp4 Gene During Osteogenic Differentiation of Bone Marrow Mesenchymal Stem Cells in Vitro

Molecular and Cellular Biochemistry. Feb, 2008  |  Pubmed ID: 18008138

In this study, we established an in vitro model of osteogenic-inductive differentiation of rat bone marrow mesenchymal stem cells (BMSCs) to determine the mechanisms and relative gene function underlying BMSCs osteogenesis. Osteoplastic differentiation of the third generation BMSCs was induced with the alpha-minimal essential medium containing beta-glyceraldehyde-3-phosphate, L: -ascorbic acid, dexamethasone and 1,25-2(OH)2 vitamin D3 prior to applying gene chip technology (also called microarray technology) for global gene expression screening. Real-time quantitative PCR (Real-time PCR) was used to determine the temporal profile of mRNA expression of regulated genes during osteogenic differentiation of BMSCs. A bioinformatic analysis was utilized to determine the functional significance of the identified osteogenic-related genes. Purkinje cell protein 4 (Pcp4) mRNA expression was identified by the gene chip screening as being up-regulated during osteoplastic differentiation of BMSCs. Real-time PCR analysis confirmed the increased expression of Pcp4 mRNA expression during osteoplastic differentiation of BMSCs with an upward trend that peaked at day 14. The bioinformatic analysis identified Pcp4 as a gene involved in the deposition of calcium and the modulation of CaM-dependent protein kinase. Thus, we hypothesize that Pcp4 osteoplastic differentiation of BMSCs is mediated in part via Pcp4-induced calcium deposition to form mineral nodules and modulation of certain signal transduction pathways of BMPs.

Intradermal/subcutaneous Immunization by Electroporation Improves Plasmid Vaccine Delivery and Potency in Pigs and Rhesus Macaques

Vaccine. Jan, 2008  |  Pubmed ID: 18082294

In an effort to improve DNA vaccine immune potency electroporation has emerged as a method of delivery of plasmids to target tissues. However, few studies have examined the use of this technology to deliver plasmid vaccines to the skin. Here we studied the effect of electroporation on DNA vaccine potency and gene delivery using skin as a target tissue in larger animal species. Using a pig model, we determined that high plasmid concentrations resulted in improved gene expression for plasmid GFP delivered by the intradermal/subcutaneous (ID/SQ) route. In a macaque model, we observed higher cellular and humoral responses to an HIV DNA vaccine, which included plasmid-encoded IL-12, with electroporation compared to ID/SQ injection alone. The induced responses were TH1 mediated. These results support that skin electroporation may have importance as an immunization approach in larger animal models.

Identification of a New Co-factor, MOG1, Required for the Full Function of Cardiac Sodium Channel Nav 1.5

The Journal of Biological Chemistry. Mar, 2008  |  Pubmed ID: 18184654

The cardiac sodium channel Nav 1.5 is essential for the physiological function of the heart and contributes to lethal cardiac arrhythmias and sudden death when mutated. Here, we report that MOG1, a small protein that is highly conserved from yeast to humans, is a central component of the channel complex and modulates the physiological function of Nav 1.5. The yeast two-hybrid screen identified MOG1 as a new protein that interacts with the cytoplasmic loop II (between transmembrane domains DII and DIII) of Nav 1.5. The interaction was further demonstrated by both in vitro glutathione S-transferase pull-down and in vivo co-immunoprecipitation assays in both HEK293 cells with co-expression of MOG1 and Nav1.5 and native cardiac cells. Co-expression of MOG1 with Nav1.5 in HEK293 cells increased sodium current densities. In neonatal myocytes, overexpression of MOG1 increased current densities nearly 2-fold. Western blot analysis revealed that MOG1 increased cell surface expression of Nav1.5, which may be the underlying mechanism by which MOG1 increased sodium current densities. Immunostaining revealed that in the heart, MOG1 was expressed in both atrial and ventricular tissues with predominant localization at the intercalated discs. In cardiomyocytes, MOG1 is mostly localized in the cell membrane and co-localized with Nav1.5. These results indicate that MOG1 is a critical regulator of sodium channel function in the heart and reveal a new cellular function for MOG1. This study further demonstrates the functional diversity of Nav1.5-binding proteins, which serve important functions for Nav1.5 under different cellular conditions.

Efficient Protein Expression from the Endogenous RNA Polymerase I Promoter Using a Human Ribosomal DNA Targeting Vector

Biochemical and Biophysical Research Communications. Mar, 2008  |  Pubmed ID: 18194663

Vector systems to deliver, integrate and express therapeutic genes in host cells are essential for gene therapy. In the present study, we investigated a novel vector system for integration and expression of a transgene. In this system, the transgene expression was driven by an endogenous RNA polymerase I (Pol I) promoter after being integrated into the ribosomal DNA (rDNA) locus. Human coagulation factor IX coding sequence (FIX), with an internal ribosome entry sites element at its leader region, was targeted into the 18S rDNA locus via homologous recombination. FIX protein expression, which was under the control of the endogenous Pol I promoter, was found to be similar to that of a moderate Pol II promoter. The average FIX expression level of the rDNA recombinants was additionally enhanced to that from a strong Pol II promoter as a result of elimination of position effects. Our data suggest the possibility of applying this system in gene therapy for hereditary diseases.

Site-specific Relaxation Kinetics of a Tryptophan Zipper Hairpin Peptide Using Temperature-jump IR Spectroscopy and Isotopic Labeling

Journal of the American Chemical Society. Mar, 2008  |  Pubmed ID: 18278908

Two antiparallel beta-strands connected by a turn make beta-hairpins an ideal model system to analyze the interactions and dynamics of beta-sheets. Site-specific conformational dynamics were studied by temperature-jump IR spectroscopy and isotopic labeling in a model based on the tryptophan zipper peptide, Trpzip2, developed by Cochran et al. (Proc. Natl. Acad. Sci. U.S.A. 2001, 98, 5578). The modified Trpzip2C peptides have nearly identical equilibrium spectral behavior as Trpzip2 showing that they also form well-characterized beta-hairpin conformations in aqueous solution. Selective introduction of 13C=O groups on opposite strands lead to distinguishable cross-strand coupling of the labeled residues as monitored in the amide I' band. These frequency patterns reflect theoretical predictions, and the coupled 13C=O band loses intensity with increase in temperature and unfolding of the hairpin. Thermal relaxation kinetics were analyzed for unlabeled and cross-strand isotopically labeled variants. T-jumps of approximately 10 degrees C induce relaxation times of a few microseconds that decrease with increase of the peptide temperature. Differences in kinetic behavior for the loss of beta-strand and gain of disordered structure can be used to distinguish localized structure dynamics by comparison of nonlabeled and labeled amide I' components. Analysis of the data supports multistate dynamic and equilibrium behavior, but because of this process it is not possible to clearly define a folding and unfolding rate. Nonetheless, site-specific relaxation kinetics could be seen to be consistent with a hydrophobic collapse hypothesis for hairpin folding.

Cell Biology: DNA Versus Membrane

Nature. Feb, 2008  |  Pubmed ID: 18288177

Multivalency Iodine Doped TiO2: Preparation, Characterization, Theoretical Studies, and Visible-light Photocatalysis

Langmuir : the ACS Journal of Surfaces and Colloids. Apr, 2008  |  Pubmed ID: 18302421

Multivalency iodine (I(7)+/I(-)) doped TiO(2) were prepared via a combination of deposition-precipitation process and hydrothermal treatment. The as-prepared samples were characterized by X-ray diffraction, transmission electron microscopy, Brunauer-Emmett-Teller surface area, UV-vis diffuse reflectance spectra, X-ray photoelectron spectroscopy, surface photovoltage spectroscopy, and electric-field-induced surface photovoltage spectroscopy. The electronic structure calculations based on the density functional theory revealed that upon doping, new states that originated from the I atom of the IO(4) group are observed near the conduction-band bottom region of TiO(2), and the excitation from the valence band of TiO(2) to the surface IO(4-) is responsible for the visible-light response of the I-doped TiO(2). The as-prepared I-doped TiO(2) showed high efficiency for the photocatalytic decomposition of gaseous acetone under visible light irradiation (lambda > 420 nm). A possible mechanism for the photocatalysis on this multivalency iodine (I(7)+/I(-)) doped TiO(2) under visible light was also proposed.

Modulation of Amyloid-beta Aggregation and Toxicity by Inosose Stereoisomers

The FEBS Journal. Apr, 2008  |  Pubmed ID: 18331344

Amyloid-beta (Abeta) aggregation and amyloid formation are key pathological features of Alzheimer's disease, and are considered to be two of the major contributing factors to neurodegeneration and dementia. Identification of small molecule inhibitors that are orally available, have low toxicity and high central nervous system bioavailability is one approach to the potential development of a disease-modifying treatment for Alzheimer's disease. We have previously identified inositol stereoisomers as exhibiting stereospecific inhibition of Abeta aggregation and toxicity in vitro and in vivo. We report here the effects of inosose versus inositol stereoisomers on Abeta fibrillogenesis as determined using CD and fluorescence spectroscopy and negative-stain electron microscopy. The inososes differ from inositols by the oxidation of one of the hydroxyl groups to a ketone. These molecules help in the further elucidation of the structure-activity relationships of inositol-Abeta interactions and identify both allo-inositol and epi-2-inosose as in vitro inhibitors of Abeta aggregation.

Expression of Glutamyl Aminopeptidase by Osteogenic Induction in Rat Bone Marrow Stromal Cells

Cell Biology International. Jul, 2008  |  Pubmed ID: 18387830

Glutamyl aminopeptidase (GluAP, EC 3.4.11.7, ENPEP) is a 130-kDa homodimeric zinc metallopeptidase which specifically cleaves the N-terminal glutamate or aspartate residue of peptidic substrates such as cholecystokinin-8 or angiotensin (Ang) II, in vitro. We used a DNA microarray hybridization (Genechip Rat Expression Array 230A, Affymetrix Inc., Santa Clara, CA, USA) to demonstrate that GluAP was upregulated in osteogenic induced rat bone marrow stromal cells (BMSCs). To compare the expression of GluAP in the osteogenic differentiation and non-osteogenic differentiation of rat BMSCs in vitro, the cells were osteogenic induced in vitro. We also performed an MTT assay, alkaline phosphatase assay, alizarin red staining, and an immunohistochemical analysis to determine the osteogenic differentiation of BMSCs. The expression of GluAP was examined by real-time polymerase chain reaction (PCR). The real-time PCR results showed that GluAP was upregulated in osteogenic differentiated BMSCs in vitro, suggesting that GluAP may be correlated with the osteogenic differentiation of BMSCs.

Combined Effects of IL-12 and Electroporation Enhances the Potency of DNA Vaccination in Macaques

Vaccine. Jun, 2008  |  Pubmed ID: 18430495

DNA vaccines are a promising technology. Historically, however, the ability of DNA vaccines to induce high response rates and strong immune responses, especially antibody responses, in non-human primates and human clinical trials has proven suboptimal. Here, we performed a pilot study in rhesus macaques to evaluate whether we could improve the immunogenicity of DNA vaccines through the use of adjuvant technology and improved delivery systems. The study consisted of four groups of animals that received: DNA by intramuscular (IM) injection, DNA with plasmid-encoded IL-12 by IM injection, DNA by IM injection with in vivo electroporation (EP), and DNA with IL-12 by IM EP. Each group was immunized three times with optimized HIV gag and env constructs. Vaccine immunogenicity was assessed by IFNgamma ELISpot, CFSE proliferation, polyfunctional flow cytometry, and antibody ELISA. Similar to previous studies, use of IL-12 as an adjuvant increased the gag and env-specific cellular responses. The use of EP to enhance plasmid delivery resulted in dramatically higher cellular as well as humoral responses. Interestingly, the use of EP to administer the DNA and IL-12 adjuvant combination resulted in the induction of higher, more efficient responses such that a 10-fold increase in antigen-specific IFNgamma(+) cells compared to IM DNA immunization was observed after a single immunization. In addition to increases in the magnitude of IFNgamma production in the initial and memory responses, the combined approach resulted in enhancements in the proliferative capacity of antigen-specific CD8(+) T cells and the amount of polyfunctional cells capable of producing IL-2 and TNFalpha in addition to IFNgamma. These data suggest that adjuvant and improved delivery methods may be able to overcome previous immunogenicity limitations in DNA vaccine technology.

Parameters for DNA Vaccination Using Adaptive Constant-current Electroporation in Mouse and Pig Models

Vaccine. Sep, 2008  |  Pubmed ID: 18450333

Enhancing the expression of DNA vaccines requires that specific conditions of delivery are optimized. We describe experiments using adaptive constant-current electroporation (EP) in mice and pigs examining parameters such as target muscle, delay between plasmid delivery and onset of EP pulses and DNA vaccine formulation; our studies show that concentrated formulations result in better expression and immunogenicity. Furthermore, various conditions of EP that limit the amount of muscle damage were measured. The results of these studies will help to advance the success of DNA vaccines in animals into success in human clinical trials.

Regulation of Blood-brain Barrier Permeability by Transient Receptor Potential Type C and Type V Calcium-permeable Channels

Microcirculation (New York, N.Y. : 1994). May, 2008  |  Pubmed ID: 18464164

To identify plasma membrane ion channels mediating calcium influx at the blood-brain barrier in response to disrupting stimuli.

Immunogenicity of Novel Consensus-based DNA Vaccines Against Chikungunya Virus

Vaccine. Sep, 2008  |  Pubmed ID: 18471943

Chikungunya virus (CHIKV) is an emerging arbovirus and is an important human pathogen. Infection of humans by CHIKV can cause a syndrome characterized by fever, headache, rash, nausea, vomiting, myalgia, arthralgia and occasionally neurological manifestations such as acute limb weakness. It is also associated with a fatal haemorrhagic condition. CHIKV is geographically distributed from Africa through Southeast Asia and South America, and its transmission to humans is mainly through the Aedes aegypti species mosquitoes. The frequency of recent epidemics in the Indian Ocean and La Reunion islands suggests that a new vector perhaps is carrying the virus, as A. aegypti are not found there. In fact, a relative the Asian tiger mosquito, Aedes albopictus, may be the culprit which has raised concerns in the world health community regarding the potential for a CHIK virus pandemic. Accordingly steps should be taken to develop methods for the control of CHIKV. Unfortunately, currently there is no specific treatment for Chikungunya virus and there is no vaccine currently available. Here we present data of a novel consensus-based approach to vaccine design for CHIKV, employing a DNA vaccine strategy. The vaccine cassette was designed based on CHIKV capsid- and envelope-specific consensus sequences with several modifications, including codon optimization, RNA optimization, the addition of a Kozak sequence, and a substituted immunoglobulin E leader sequence. The expression of capsid, envelope E1 and E1 was evaluated using T7-coupled transcription/translation and immunoblot analysis. A recently developed, adaptive constant-current electroporation technique was used to immunize C57BL/6 mice with an intramuscular injection of plasmid coding for the CHIK-Capsid, E1 and E2. Analysis of cellular immune responses, including epitope mapping, demonstrates that electroporation of these constructs induces both potent and broad cellular immunity. In addition, antibody ELISAs demonstrate that these synthetic immunogens are capable of inducing high titer antibodies capable of recognizing native antigen. Taken together, these data support further study of the use of consensus CHIK antigens in a potential vaccine cocktail.

First Homo-peptides Undergoing a Reversible 3(10)-helix/alpha-helix Transition: Critical Main-chain Length

Biopolymers. 2008  |  Pubmed ID: 18481806

The difference in length between the more elongated peptide 3(10)-helix and the more compact alpha-helix is about 0.4 A/residue. This property makes the 3(10)-/alpha-helix reversible conversion very promising as a molecular switching tool between the N- and C-terminal functions of a peptide backbone. In this work, using homo-peptides of various main-chain length, all based on the strongly helicogenic, Calpha-tetrasubstituted alpha-amino acid Calpha-methyl-L-valine, we show that a well defined, solvent controlled, reversible 3(10)-/alpha-helix transition takes place even in a homo-oligomer as short as a terminally blocked hexapeptide. Homo-peptide sequences blocked as a urethane or an acetamide at the N-terminus and as a methyl ester or an N-alkyl amide at the C-terminus are all appropriate. The nature of the occurring helical species in the various solvents tested was assessed by electronic or vibrational circular dichroism.

Vibrational Circular Dichroism and IR Spectral Analysis As a Test of Theoretical Conformational Modeling for a Cyclic Hexapeptide

Chirality. Nov, 2008  |  Pubmed ID: 18506832

A model cyclohexapeptide, cyclo-(Phe-(D)Pro-Gly-Arg-Gly-Asp) was synthesized and its IR and VCD spectra were used as a test of density functional theory (DFT) level predictions of spectral intensities for a peptide with a nonrepeating but partially constricted conformation. Peptide structure and flexibility was estimated by molecular dynamics (MD) simulations and the spectra were simulated using full quantum mechanical (QM) approaches for the complete peptide and for simplified models with truncated side chains. After simulated annealing, the backbone conformation of the ring structure is relatively stable, consisting of a normal beta-turn and a tight loop (no H-bond) which does not vary over short trajectories. Only in quite long MD runs at high temperatures do other conformations appear. MD simulations were carried out for the cyclic peptide in water and in TFE, which match experimental solvents, as well as with and without protonation of the Asp carboxyl group. DFT spectral simulations were made using the annealed structure and were extended to include basis set variation, to determine an optimal computational approach, and solvent simulation with a polarized continuum model (PCM). Stepwise full DFT simulation of spectra was done for various sequences with the same backbone geometry but based on (1) solely Gly residues, (2) Ala substitution except Gly and Pro, and (3) complete sequences with side chains. Additionally, a selection of structures was used to compute IR and VCD spectra with the optimal method to determine structural variation effects. The side chains, especially the Asp-COOH and Arg-NH(2) transitions, had an impact on the computed amide frequencies, IR intensities and VCD pattern. Since experimentally these groups would have little chirality, due to conformational variation, they do not impact the observed VCD spectra. Correcting for frequency shifts, the Ala model for the cyclopeptide gives the clearest representation of the amide VCD. The experimental sign pattern for the amide I' band in D(2)O and also the sharper, more intense amide I VCD band in TFE was seen to some degree in one conformer with Type II' turns, but the data favor a mix of structures.

Therapeutic Vaccination with Simian Immunodeficiency Virus (SIV)-DNA + IL-12 or IL-15 Induces Distinct CD8 Memory Subsets in SIV-infected Macaques

Journal of Immunology (Baltimore, Md. : 1950). Jun, 2008  |  Pubmed ID: 18523260

DNA vaccination is an invaluable approach for immune therapy in that it lacks vector interference and thus permits repeated vaccination boosts. However, by themselves, DNA-based vaccines are typically poor inducers of Ag-specific immunity in humans and non-human primates. Cytokines, such as IL-12 and IL-15, have been shown to be potent adjuvants for the induction and maintenance of cellular immune responses, in particular during HIV infection. In this study, we examined the ability of therapeutic vaccination with SIV-DNA+IL-12 or IL-15 as molecular adjuvants to improve DNA vaccine potency and to enhance memory immune responses in SIV-infected macaques. Our results demonstrate that incorporating IL-12 into the vaccine induces SIV-specific CD8 effector memory T cell (T(EM)) functional responses and enhances the capacity of IFN-gamma-producing CD8 T(EM) cells to produce TNF. Lower levels of PD-1 were expressed on T cells acquiring dual function upon vaccination as compared with mono-functional CD8 T(EM) cells. Finally, a boost with SIV-DNA+IL-15 triggered most T cell memory subsets in macaques primed with either DNA-SIV or placebo but only CD8 T(EM) in macaques primed with SIV-DNA+IL-12. These results indicate that plasmid IL-12 and IL-15 cytokines represent a significant addition to enhance the ability of therapeutic DNA vaccines to induce better immunity.

[Experimental Study on the Development of Tissue-engineered Tooth Germ with Heterotopic Allotransplantation]

Sichuan Da Xue Xue Bao. Yi Xue Ban = Journal of Sichuan University. Medical Science Edition. Mar, 2008  |  Pubmed ID: 18630703

To compare the growth and development of tissue engineered tooth germ implanted into different tissues, and explore a suitable growing environment for the tissue engineered teeth in vivo.

[Construction of Tissue Culture Model in Vitro and Investigation of Transforming Growth Factor Promoting Pulp Fibroblast to Differentiate into the Odontoblast]

Sichuan Da Xue Xue Bao. Yi Xue Ban = Journal of Sichuan University. Medical Science Edition. Mar, 2008  |  Pubmed ID: 18630704

To construct the tissue culture model in vitro, and investigate the potential of dental pulp fibroblast differentiating into the odontoblast and the promoting role of transforming growth factor beta1 (TGF-beta1) on it.

[Spontaneous Odontogenic Differentiation and Critical Gene Expression of Mouse Dental Papilla Mesenchymal Cell in Vitro]

Sichuan Da Xue Xue Bao. Yi Xue Ban = Journal of Sichuan University. Medical Science Edition. Mar, 2008  |  Pubmed ID: 18630705

To observe the spontaneous odontogenic differentiation of mouse dental papilla mesenchymal cells in blood serum medium. And to detect the critical gene expression of correlated transcription factors what are specific to odontogenic and osteogenic differentiation.

[Expression of Odontogenic and Osteogenic Genes in Bone Marrow Mesenchymal Stem Cells with Overexpression of Mouse Dentin Sialophosphoprotein]

Sichuan Da Xue Xue Bao. Yi Xue Ban = Journal of Sichuan University. Medical Science Edition. Mar, 2008  |  Pubmed ID: 18630706

To observe the overexpression of dentin sialophosphoprotein (DSPP) in mouse bone marrow mesenchymal stem cells (BM-MSC) and the expression of specific gene involved in odontogenic and osteogenic differentiation in transfected cells.

[Immunolocalization of Receptor Activator of NF-kappaB Ligand and Osteoprotegerin During Mouse Mandibular First Molar Eruption]

Zhonghua Kou Qiang Yi Xue Za Zhi = Zhonghua Kouqiang Yixue Zazhi = Chinese Journal of Stomatology. Mar, 2008  |  Pubmed ID: 18788552

To investigate the immunolocalization of receptor activator of nuclear factor-kappa B ligand (RANKL) and osteoprotegerin (OPG), and to explore the correlation between their expressions and activity of osteoclast during first mandibular molar eruption.

Human Immunodeficiency Virus Type 1 Nef Induces Programmed Death 1 Expression Through a P38 Mitogen-activated Protein Kinase-dependent Mechanism

Journal of Virology. Dec, 2008  |  Pubmed ID: 18799583

Chronic viral infection is characterized by the functional impairment of virus-specific T-cell responses. Recent evidence has suggested that the inhibitory receptor programmed death 1 (PD-1) is specifically upregulated on antigen-specific T cells during various chronic viral infections. Indeed, it has been reported that human immunodeficiency virus (HIV)-specific T cells express elevated levels of PD-1 and that this expression correlates with the viral load and inversely with CD4(+) T-cell counts. More importantly, antibody blockade of the PD-1/PD-L1 pathway was sufficient to both increase and stimulate virus-specific T-cell proliferation and cytokine production. However, the mechanisms that mediate HIV-induced PD-1 upregulation are not known. Here, we provide evidence that the HIV type 1 (HIV-1) accessory protein Nef can transcriptionally induce the expression of PD-1 during infection in vitro. Nef-induced PD-1 upregulation requires its proline-rich motif and the activation of the downstream kinase p38. Further, inhibition of Nef activity by p38 MAPK inhibitor effectively blocked PD-1 upregulation, suggesting that p38 MAPK activation is an important initiating event in Nef-mediated PD-1 expression in HIV-1-infected cells. These data demonstrate an important signaling event of Nef in HIV-1 pathogenesis.

Degradation of Benzene over a Zinc Germanate Photocatalyst Under Ambient Conditions

Environmental Science & Technology. Oct, 2008  |  Pubmed ID: 18939575

A rod-shaped Zn2GeO4 photocatalyst has been successfully prepared by a surfactant-assisted hydrothermal method. The photocatalyst was characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, UV/vis, N2 adsorption-desorption, and FTIR techniques. The photocatalytic activity of the sample was evaluated by the decomposition of benzene in the gas phase under UV light illumination and was compared with that of bulk Zn2GeO4, commercial titania (Degussa P25), and Pt/P25. The results revealed that the Zn2GeO4 nanorods had the best photocatalytic activity for mineralizing benzene to CO2 among the catalysts examined. No obvious deactivation of Zn2GeO4 nanorods was observed during the prolonged operation of 140 h. It was found that the Zn2GeO4 was also more active and stable than TiO2-based catalysts toward photocatalytic decomposition of other volatile aromatic pollutants (e.g., toluene and ethylbenzene).

Dentin Sialophosphoprotein-promoted Mineralization and Expression of Odontogenic Genes in Adipose-derived Stromal Cells

Cells, Tissues, Organs. 2008  |  Pubmed ID: 17957093

Dentin sialophosphoprotein (DSPP) is an extracellular matrix, typically dentin- and bone-specific gene, which plays an important role in dentin mineralization and tooth development. Adipose-derived stromal cells (ADSCs) are considered to contain a group of pluripotent mesenchymal stem cells which are capable of mineralization either in vitro or in vivo. In the present study, we hypothesized that overexpression of DSPP would promote mineralization in ADSCs. Our results showed that infection of DSPP-expressing adenovirus (Ad-DSPP) enhanced expression of genes related to mineralization, such as Cbfa1,Osx,BSP, OCN and DMP1 in ADSCs. Alkaline phosphatase activity was also confirmed in Ad-DSPP-infected ADSCs by cytochemistry and alkaline phosphatase activity assay. Mineralization assay indicated that Ad-DSPP-infected ADSCs were able to form mineralized nodules. Another finding in this study is that early odontogenic marker genes such as Msx1, Msx2, Lhx7 and Pax9 were expressed in DSPP-overexpressed ADSCs. Thus, our results suggested that overexpression of DSPP promoted mineralization of ADSCs, and together with the expression of early odontogenic marker genes, implied that these cells may differentiate into functional odontoblast-like cells.

Bone Regeneration by BMP-2 Enhanced Adipose Stem Cells Loading on Alginate Gel

Histochemistry and Cell Biology. Feb, 2008  |  Pubmed ID: 17978832

Adipose stem cells (ASCs) have the potential to differentiate into a variety of cell lineages both in vitro and in vivo. In this study, ASCs were harvested from normal Sprague-Dawley (SD) rats and transfected by BMP-2 gene before they were loaded on alginate. The ability of bone regeneration was determined in rat critical-size cranial defects. An 8-mm diameter defect was created in the calvarias of 36 rats; these rats were divided into three groups. In experimental group, the defects were filled with alginate gel combined with BMP-2 transfected ASCs; in negative control group, the defects were filled with alginate gel mixed with normal ASCs; in blank controls, the defects were filled with cell-free alginate gel. Four rats of each group were killed and the cranial defect sites were observed at 4, 8 and 16 weeks after surgery. There was complete repair of cranial defects in experimental group using the alginate gel loading BMP-2 transfected ASC, but only partial repair in negative controls and in the blank control. The engineering approach combining BMP-2 enhanced ASCs with alginate gel can therefore stimulate bone regeneration and repair for the large size bone defects.

Flavonoids from Chinese Viscum Coloratum Produce Cytoprotective Effects Against Ischemic Myocardial Injuries: Inhibitory Effect of Flavonoids on PAF-induced Ca2+ Overload

Phytotherapy Research : PTR. Jan, 2008  |  Pubmed ID: 17724771

Viscum coloratum has been used in the indigenous system of medicine for the treatment of various diseases such as myocardial ischemia and arrhythmia. Platelet-activating factor (PAF) is an important player in cardiovascular diseases. The aim of this study was to investigate the protective effects of Viscum coloratum flavonoids (VCF) against ischemic myocardial injuries in vivo and to further investigate its regulatory effect on PAF. Studies were performed in a rat model of myocardial infarction and in isolated myocytes. It was found that VCF relieved myocardial injuries during ischemia. PAF (10(-11) m) significantly increased the intracellular free Ca2+ concentration ([Ca2+]i) and VCF inhibited the changes induced by PAF in single cardiac myocytes. The results suggest that VCF can improve cardiac function and that VCF reduces ischemic myocardial injuries via blocking the signaling pathway of PAF. Therefore, PAF blockers may be candidate drugs for preventing cardiac injuries during ischemia/reperfusion, and subsequently improving cardiac function.

Odontogenic Differentiation of Adipose-derived Stem Cells for Tooth Regeneration: Necessity, Possibility, and Strategy

Medical Hypotheses. 2008  |  Pubmed ID: 17703893

Tooth regeneration using tissue engineering concepts is a promising biological approach to solving problems of tooth loss in elderly patients. The seeding cells, however, for tooth regeneration such as odontoblasts from dental germ, stem cells from dental pulp and deciduous teeth, and ectomesenchymal cells from the first branchial arch are difficult, even impossible to harvest in clinic. Bone marrow mesenchymal stem cells have odontogenic capacity, but their differentiation abilities significantly decrease with the increasing age of the donors. Therefore, the cells mentioned above are not practical in the clinical application of tooth regeneration in the old. Adipose derived stem cells have many clinical advantages over bone marrow mesenchymal stem cells, and their differentiation potential can be maintained with aging. Here we propose the hypothesis that adipose derived stem cells could be induced into odontogenic lineage and might be used as suitable seeding cells for tooth regeneration to replace the lost tooth of elderly patients.

[Fatigue Symptoms of Medical Staff and Influential Factors]

Zhonghua Lao Dong Wei Sheng Zhi Ye Bing Za Zhi = Zhonghua Laodong Weisheng Zhiyebing Zazhi = Chinese Journal of Industrial Hygiene and Occupational Diseases. Sep, 2008  |  Pubmed ID: 19309588

Hydrothermal Synthesis and Performance of a Novel Nanocrystalline Pb(2)Sn(2)O(6) Photocatalyst

Nanotechnology. Dec, 2008  |  Pubmed ID: 19942782

A novel nanocrystalline Pb(2)Sn(2)O(6) photocatalyst was prepared successfully for the first time by a hydrothermal process at 180 degrees C for 12 h. The samples were characterized by an x-ray diffractometer (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), surface area (BET) and ultraviolet-visible (UV-vis) spectroscopes. The results showed that the pH value played an important role in controlling the phase formation and crystallite sizes of the Pb(2)Sn(2)O(6). A single phase could be obtained at a pH>/=9. A possible reaction mechanism in the hydrothermal process was also proposed. The average particle size for the sample prepared at pH = 13 was only about 9 nm, and the BET surface area was as large as 76.7 m(2) g(-1). The N(2) adsorption-desorption isotherms and pore size distribution curve demonstrate a mesoporous structure with a narrow pore size distribution. As a novel photocatalyst, the prepared Pb(2)Sn(2)O(6) samples exhibit powerful photocatalytic activity for the decomposition of methyl orange under 365 nm UV light irradiation. Furthermore, it was found that the degradation process may be initiated directly by photogenerated holes rather than commonly sensed hydroxyl radicals.

Cross-strand Coupling and Site-specific Unfolding Thermodynamics of a Trpzip Beta-hairpin Peptide Using 13C Isotopic Labeling and IR Spectroscopy

The Journal of Physical Chemistry. B. Apr, 2009  |  Pubmed ID: 19326892

Conformational properties of a 12-residue tryptophan zipper (trpzip) beta-hairpin peptide (AWAWENGKWAWK-NH(2), a modification of the original trpzip2 sequence) are analyzed under equilibrium conditions using ECD and IR spectra of a series of variants, singly and doubly C(1)-labeled with (13)C on the amide CO. The characteristic features of the (13)CO component of the amide I' IR band and their sensitivity to the local structure of the peptide are used to differentiate stabilities for parts of the hairpin structure. Doubly labeled peptide spectra indicate that the ends of the beta-strands are frayed and that the center part is more stable as would be expected from formation of a stable hydrophobic core consisting of four tryptophan residues, and supported by MD simulations. NMR analyses were used to determine a best fit solution structure that is in close agreement with that of trpzip2, except for a small variation in the turn geometry. The distinct vibrational coupling patterns of the labeled sites based on this structure are also well matched by ab initio DFT-level calculations of their IR spectral patterns. Thermal unfolding of the peptides as studied with CD spectra could be fit with an apparent two-state transition model. ECD senses only the tryptophan interactions (tertiary-like) and their overall environment, as shown by TD-DFT modeling of the Trp-Trp pi-pi ECD. However, variation of the amide I IR spectra of (13)C-isotopomers showed that the thermal unfolding process is not cooperative in terms of the peptide backbone (secondary structure), since the transition temperatures sensed for labeled modes differ from those for the whole peptide. The thermal data also evidence dependence on concentration and pH but these cause little spectral variation. This study illustrates the consequences of multistate conformational change at the residue- or sequence-specific level in a system whose structure is dominated by hydrophobic collapse.

Effect of Bu-Zhong-Yi-Qi-Tang on Deficiency of N-glycan/nitric Oxide and Islet Damage Induced by Streptozotocin in Diabetic Rats

World Journal of Gastroenterology : WJG. Apr, 2009  |  Pubmed ID: 19360916

To investigate the effect of Bu-Zhong-Yi-Qi-Tang (Decoction for Reinforcing Middle Jiao and Replenishing Qi) on deficiency of N-glycan/nitric oxide (NO) and islet damage induced by injecting two medium doses of streptozotocin (STZ).

First Homo-peptides Undergoing a Reversible 3(10)-helix to Alpha-helix Transition

Advances in Experimental Medicine and Biology. 2009  |  Pubmed ID: 19400089

[Isolation, Identification and Rumen Fermentation Characteristics of Propionibacterium Acnes]

Wei Sheng Wu Xue Bao = Acta Microbiologica Sinica. Feb, 2009  |  Pubmed ID: 19445170

Characteristic of energy metabolism in ruminant is a negative energy balance in perinatal period. Propionic acid from ruminal microbe fermentation is a vital glyconeogenesis substrate for preventing negative energy balance. We isolated and screened a Propionibacterium acnes strain from health cow rumen fluid, and studied its rumen fermentation characteristics.

Localisation of DivIVA by Targeting to Negatively Curved Membranes

The EMBO Journal. Aug, 2009  |  Pubmed ID: 19478798

DivIVA is a conserved protein in Gram-positive bacteria and involved in various processes related to cell growth, cell division and spore formation. DivIVA is specifically targeted to cell division sites and cell poles. In Bacillus subtilis, DivIVA helps to localise other proteins, such as the conserved cell division inhibitor proteins, MinC/MinD, and the chromosome segregation protein, RacA. Little is known about the mechanism that localises DivIVA. Here we show that DivIVA binds to liposomes, and that the N terminus harbours the membrane targeting sequence. The purified protein can stimulate binding of RacA to membranes. In mutants with aberrant cell shapes, DivIVA accumulates where the cell membrane is most strongly curved. On the basis of electron microscopic studies and other data, we propose that this is due to molecular bridging of the curvature by DivIVA multimers. This model may explain why DivIVA localises at cell division sites. A Monte-Carlo simulation study showed that molecular bridging can be a general mechanism for binding of proteins to negatively curved membranes.

A 3(10)-helical Pentapeptide in Water: Interplay of Alpha,alpha-disubstituted Amino Acids and the Central Residue on Structure Formation

Biopolymers. 2009  |  Pubmed ID: 19489061

C(alpha,alpha)-disubstituted amino acids (alphaalphaAAs) are widely used to conformationally constrain peptides. A series of pentapeptides containing dipropylglycine (Dpg) at alternating positions and their alpha-amino acid counterpart L-norvaline (Nva) analogues were synthesized to fully investigate the impact of Dpg on peptide backbone structure in aqueous solution. CD, VCD, and NMR spectral analysis suggest that Dpg containing peptides adopt more ordered structures relative to their Nva containing analogues. The central residues (Ala, Thr, Tyr, Val) and the charged side-chains of Glu and Lys play important roles in the degree of peptide folding. Hydrophobic and branched residues (Val, Tyr) at the central position of the peptide produce greater folding as judged by CD and NMR. Variation of the chemical shift with temperature (Deltadelta/DeltaT NH) of Ac-Glu-Dpg-Tyr-Dpg-Lys-NH(2) suggests a series of i --> i + 3 hydrogen bonds between the N-terminal acetyl carbonyl and the Tyr(3) NH, and the Glu(1) carbonyl and the Dpg(4) NH. The solution conformation of Ac-Glu-Dpg-Tyr-Dpg-Lys-NH(2) calculated from NMR-derived constraints shows a 3(10)-helical structure (two repetitive type-III beta-turns) at residues 1-4, which is supported by 2D NMR, CD, and VCD spectra. Analysis of NMR-derived models of these peptides suggest that there is a strong hydrophobic interaction of the pro-S propyl side chain of Dpg(2) and the Tyr(3) side-chain that may be a strong stabilizing force of the peptide folding in water.

Noc Protein Binds to Specific DNA Sequences to Coordinate Cell Division with Chromosome Segregation

The EMBO Journal. Jul, 2009  |  Pubmed ID: 19494834

Coordination of chromosome segregation and cytokinesis is crucial for efficient cell proliferation. In Bacillus subtilis, the nucleoid occlusion protein Noc protects the chromosomes by associating with the chromosome and preventing cell division in its vicinity. Using protein localization, ChAP-on-Chip and bioinformatics, we have identified a consensus Noc-binding DNA sequence (NBS), and have shown that Noc is targeted to about 70 discrete regions scattered around the chromosome, though absent from a large region around the replication terminus. Purified Noc bound specifically to an NBS in vitro. NBSs inserted near the replication terminus bound Noc-YFP and caused a delay in cell division. An autonomous plasmid carrying an NBS array recruited Noc-YFP and conferred a severe Noc-dependent inhibition of cell division. This shows that Noc is a potent inhibitor of division, but that its activity is strictly localized by the interaction with NBS sites in vivo. We propose that Noc serves not only as a spatial regulator of cell division to protect the nucleoid, but also as a timing device with an important role in the coordination of chromosome segregation and cell division.

Cellular Localization of Choline-utilization Proteins in Streptococcus Pneumoniae Using Novel Fluorescent Reporter Systems

Molecular Microbiology. Oct, 2009  |  Pubmed ID: 19737355

The molecular mechanisms underlying cell growth, cell division and pathogenesis in Streptococcus pneumoniae are still not fully understood. Single-cell methodologies are potentially of great value to investigate S. pneumoniae cell biology. Here, we report the construction of novel plasmids for single and double cross-over integration of functional fusions to the gene encoding a fast folding variant of the green fluorescent protein (GFP) into the S. pneumoniae chromosome. We have also established a zinc-inducible system for the fine control of gfp-fusion gene expression and for protein depletion experiments in S. pneumoniae. Using this novel single cell toolkit, we have examined the cellular localization of the proteins involved in the essential process of choline decoration of S. pneumoniae teichoic acid. GFP fusions to LicA and LicC, enzymes involved in the activation of choline, showed a cytoplasmic distribution, as predicted from their primary sequences. A GFP fusion to the choline importer protein LicB showed clear membrane localization. GFP fusions to LicD1 and LicD2, enzymes responsible for loading of teichoic acid subunits with choline, are also membrane-associated, even though both proteins lack any obvious membrane spanning domain. These results indicate that the decoration of teichoic acid by the LicD enzymes is a membrane-associated process presumably occurring at lipid-linked teichoic acid precursors.

Co-immunization with an Optimized Plasmid-encoded Immune Stimulatory Interleukin, High-mobility Group Box 1 Protein, Results in Enhanced Interferon-gamma Secretion by Antigen-specific CD8 T Cells

Immunology. Sep, 2009  |  Pubmed ID: 19740322

DNA vaccination is a novel immunization strategy that has great potential for the development of vaccines and immune therapeutics. This strategy has been highly effective in mice, but is less immunogenic in non-human primates and in humans. Enhancing DNA vaccine potency remains a challenge. It is likely that antigen-presenting cells (APCs), and especially dendritic cells (DCs), play a significant role in the presentation of the vaccine antigen to the immune system. A new study reports the synergistic recruitment, expansion and activation of DCs in vivo by high-mobility group box 1 (HMGB1) protein. Such combinational strategies for delivering vaccine in a single, simple platform will hypothetically bolster the cellular immunity in vivo. Here, we combined plasmid encoding human immunodeficiency virus-1 (HIV-1) Gag and Env with an HMGB1 plasmid as a DNA adjuvant in BALB/c mice (by intramuscular immunization via electroporation), and humoral and cellular responses were measured. Co-administration of this potent immunostimulatory adjuvant strongly enhanced the cellular interferon-gamma (IFN-gamma) and humoral immune response compared with that obtained in mice immunized with vaccine only. Our results show that co-immunization with HMGB1 can have a strong adjuvant activity, driving strong cellular and humoral immunity that may be an effective immunological adjuvant in DNA vaccination against HIV-1.

Template-free Hydrothermal Synthesis and Photocatalytic Performances of Novel Bi2SiO5 Nanosheets

Inorganic Chemistry. Oct, 2009  |  Pubmed ID: 19780612

Orthorhombic Bi(2)SiO(5) nanosheets with thicknesses of 10-20 nm were first synthesized by a template-free hydrothermal synthesis process using Bi(NO(3))(3) and different Si sources as raw materials. The as-prepared samples were characterized by X-ray diffraction, Brunauer-Emmett-Teller (BET) surface area analysis, UV-vis diffuse reflectance spectroscopy, scanning electron microscopy, high-resolution transmission electron microscopy, and a photoluminescence technique with terephthalic acid. The results showed that different precursors led to samples with different morphologies, particle sizes, and BET surface areas. As a novel photocatalyst, the photocatalytic performances of Bi(2)SiO(5) samples were evaluated by the photocatalytic degradation of salicylic acid and gaseous benzene. The results revealed that the sample obtained from Na(2)SiO(3) as a precursor exhibited higher activity than that from (C(2)H(5)O)(4)Si due to its biscuit-like morphology, a smaller particle size, and a higher BET surface areas.

Role of Tryptophan-tryptophan Interactions in Trpzip Beta-hairpin Formation, Structure, and Stability

Biochemistry. Nov, 2009  |  Pubmed ID: 19788311

A series of beta-hairpin peptides based on variations of the TrpZip2 sequence, SWTWENGKWTWK, of Cochran and co-workers were studied using electronic circular dichroism (CD) and infrared (IR) spectra by varying temperature and pH. Selected tryptophan residues were substituted with Val to test the impact of specific Trp interactions on hairpin stability. Native-state structures of two of the variants were determined using 2-D NMR and shown to have the same cross-strand edge-to-face Trp-Trp interaction as in Trpzip2. Thermally induced conformational changes of the hairpins formed with these various sequences were studied with CD and IR. Thermodynamic analyses of the temperature variation of both IR (as analyzed using the amide I' frequency shift) and CD (intensity) spectra were fit to a two-state model that yielded different T(m) values, consistent with a multistate process of folding/unfolding. At low pH these differences were minimized, suggesting a change in the energetics. Cross-strand interacting Trp residues with an edge-to-face orientation had the strongest impact on hairpin stability, as judged by CD and IR data. The diagonal interaction between Trp2 and Trp9, which have a more parallel orientation in Trpzip2, contribute to the spectral response but do not independently stabilize the structure. Comparative study of these various physical interactions emphasizes the complex folding pathways that are important even for these small peptides.

It Takes Two DNA Translocases to Untangle Chromosomes from the Division Septum

Molecular Microbiology. Nov, 2009  |  Pubmed ID: 19788546

The DNA translocase function of Bacillus subtilis SpoIIIE is essential for spore development and is important during vegetative growth for moving trapped chromosomal DNA away from division septa. Two papers in this issue of Molecular Microbiology, from the teams of Peter Graumann and William Burkholder, have characterized a second SpoIIIE/FtsK-like protein in B. subtilis, SftA. This protein lacks any recognizable transmembrane domain possessed by the other characterized members of the family, yet the protein is shown to be associated with the division septum and, like SpoIIIE, is required for clearing DNA from the septum. However, SftA and SpoIIIE act at different stages of septation and together they ensure maximum fidelity in chromosome segregation.

Photochemical Synthesis of Submicron- and Nano-scale Cu2O Particles

Journal of Colloid and Interface Science. May, 2009  |  Pubmed ID: 19278684

Submicron- and nano-scale cuprous oxide particles derived from copper acetate and copper gluconate complexes were synthesized via a photochemical route in polar media without further reducing agents. The morphology, composition, and phase structure of as-prepared Cu(2)O were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM), and X-ray photoelectron spectroscopy (XPS). Factors affecting the morphology and size of the Cu(2)O products have been examined in detail to determine the optimum parameters to achieve a controllable synthesis. The results show that solvent is the most key factor in size- and shape-control of the Cu(2)O products. Water induces the formation of submicron particles, while alcohol results in nanoscale particles. The photochemical growth of Cu(2)O particles can be fine tuned by varying the parameters of the reaction procedure, e.g. solvent, precursor ligand, and additive. The IR results indicate that these Cu(2)O particles result from the photoinduced intramolecular electron transfer between metal and ligand. The method can be easily controlled and is expected to be applicable for the preparation of cuprous oxide supported catalysts.

Randomized Phase II Trial of Denosumab in Patients with Bone Metastases from Prostate Cancer, Breast Cancer, or Other Neoplasms After Intravenous Bisphosphonates

Journal of Clinical Oncology : Official Journal of the American Society of Clinical Oncology. Apr, 2009  |  Pubmed ID: 19237632

Patients with bone metastases and elevated urinary N-telopeptide (uNTx), representing excessive bone resorption, are at increased risk for skeletal-related events (SREs), cancer progression, and death. Osteoclast-mediated bone resorption is regulated by RANKL. We evaluated the effect of denosumab, a fully human monoclonal antibody against RANKL, in patients with bone metastases and elevated uNTx levels despite ongoing intravenous (IV) bisphosphonate (BP) therapy.

Poly[[triaqua(butane-1,2,3,4-tetra-carboxyl-ato)dimanganese(II)] Mono-hydrate]

Acta Crystallographica. Section E, Structure Reports Online. 2009  |  Pubmed ID: 21578161

The asymmetric unit of the title Mn(II) coordination polymer, {[Mn(2)(C(8)H(6)O(8))(H(2)O)(3)]·H(2)O}(n), contains two crystallographic-ally independent Mn(II) cations, two half butane-1,2,3,4-tetra-carboxyl-ato anions, each lying on a centre of inversion, and four water mol-ecules. The Mn(II) cation has a distorted octa-hedral coordination environment. One Mn centre is coordinated by four carboxyl-ate O atoms from two different anions and two water O atoms. The other Mn centre is coordinated by five carboxyl-ate O atoms from four different anions and one water O atom. One water mol-ecule does not coordinate to a Mn centre. The crystal packing is stabilized by several O-H⋯O hydrogen bonds, forming a three-dimensional framework.

Relationship Between Hydrophobic Interactions and Secondary Structure Stability for Trpzip Beta-hairpin Peptides

Biochemistry. Feb, 2009  |  Pubmed ID: 19173596

The temperature-induced beta-hairpin stabilities of selected mutations of the Trpzip1 peptide, SWTWEGNKWTWK (WWWW), have been investigated by electronic circular dichroism (CD), Raman, and FT-IR spectroscopies. The tryptophan (Trp) residues in the original Trpzip1 sequence were systematically substituted with tyrosine (Tyr) in different positions to test the impact of Trp interactions on the beta-hairpin structure and stability. The CD intensity at approximately 228 nm, which arises from Trp-Trp interactions (tertiary structure), and the amide I' IR absorbance at approximately 1635 cm(-1) (secondary structure) have been measured over a range of temperatures to investigate the impact of Tyr substitution on beta-hairpin thermal stability in Trpzip peptides. Mutation from Trp to Tyr in the Trpzip1 sequence reduces the extent of beta-hairpin structure and monotonically decreases the beta-hairpin stability of Trpzip1 mutant peptides with an increasing number of Tyr substitutions. Substituted Trpzip peptides with just one pair of Trp-Trp interactions close to either the terminal residues (WYYW) or the turn (YWWY) have similar stabilities. Comparison of conformational transitions monitored by CD and IR reveals them to have multistate behavior in which the temperature-induced disruption of the Trp-Trp interaction (tertiary structure) occurs at a lower temperature than the unfolding of the secondary structure.

Effects of Rapid Distraction Rate on New Bone Formation During Mandibular Distraction Osteogenesis in Goats

Injury. Aug, 2009  |  Pubmed ID: 19217101

Distraction osteogenesis typically requires a long treatment period, which can lead to bone and soft-tissue infection and considerable patient discomfort. Use of a rapid distraction rate in craniofacial distraction osteogenesis to shorten the distraction period is possible owing to the unique characteristics of craniofacial bones, including an abundant blood supply and rapid bone healing compared with long bones. The effects of using a rapid distraction rate in the treatment of craniofacial deformities are currently unclear, however. The objective of this study was to investigate the effects of a rapid distraction rate on new bone formation during mandibular distraction osteogenesis in goats.

PAF Exerts a Direct Apoptotic Effect on the Rat H9c2 Cardiomyocytes in Ca2+-dependent Manner

International Journal of Cardiology. Aug, 2010  |  Pubmed ID: 19237210

Previous studies suggested that platelet-activating factor (PAF) plays an important role in ischemic diseases. Apoptosis has been implicated in myocardial infarction-related cell death. The present study was designed to determine whether PAF could induce apoptosis in cardiac myocytes and the underlying mechanisms by which PAF causes apoptosis.

Serum Regulates Adipogenesis of Mesenchymal Stem Cells Via MEK/ERK-dependent PPARgamma Expression and Phosphorylation

Journal of Cellular and Molecular Medicine. Apr, 2010  |  Pubmed ID: 19243475

Mesenchymal stem cells (MSCs) provide us an excellent cellular model to uncover the molecular mechanisms underlying adipogenic differentiation of adult stem cells. PPARgamma had been considered as an important molecular marker of cells undergoing adipogenic differentiation. Here, we demonstrated that expression and phosphorylation of PPARgamma could be found in bone marrow-derived MSCs cultured in expansion medium without any adipogenic additives (dexamethasone, IBMX, insulin or indomethacin). Then, PPARgamma was dephosphorylated in MSCs during the process of adipogenic differentiation. We then found that inhibition of MEK activation by specific inhibitor (PD98059) counteracted the PPARgamma expression and phosphorylation. However, expression and phosphorylation of PPARgamma did not present in MSCs cultured in medium with lower serum concentration. When these MSCs differentiated into adipocytes, no phosphorylation could be detected to accompany the expression of PPARgamma. Moreover, exposure of MSCs to higher concentration of serum induced stronger PPARgamma expression, and subsequently enhanced their adipogenesis. These data suggested that activation of the MEK/ERK signalling pathway by high serum concentration promoted PPARgamma expression and phosphorylation, and subsequently enhanced adipogenic differentiation of MSCs.

Osteogenic Induction of Adipose-derived Stromal Cells: Not a Requirement for Bone Formation in Vivo

Artificial Organs. Jan, 2010  |  Pubmed ID: 19821812

Osteogenic induction was regarded as an indispensable step for adipose-derived stromal cells (ADSCs) to have osteogenic ability. Non-induced ADSCs can also produce bone in vivo and heal skeletal defects. The present study aimed to compare the bone-forming ability of osteogenically induced ADSCs and non-induced ADSCs in vivo. Tissue-engineered constructs were prepared from osteogenically induced or non-induced ADSCs and porous hydroxyapatite/beta-tricalcium phosphate scaffolds. A scaffold without cells and an empty defect group were used as control. All were implanted in rat critical calvarial defects. After implantation for 6 and 12 weeks, bone formation was analyzed using histomorphometry and microcomputed tomography; there were no significant differences in the formation of new bone between osteogenically induced ADSCs and non-induced ADSCs (P > 0.05). In conclusion, osteogenic induction of ADSCs is not an indispensable step for bone formation in vivo. Non-induced ADSCs can also be used as seeding cells to construct bone tissue.

The Quantitative Research of Composite Immune Indicator for Crustacean

Fish & Shellfish Immunology. Jan, 2010  |  Pubmed ID: 19874895

Through analyzing the immunity indicators in recent crustacean research, two defects are pointed in comprehensive immunity evaluation, 1) the integrant indicators cannot comprehensively reflect the change of immunity, and 2) the conclusions that obtained from different indicators of immunity level cannot be compared objectively and scientifically. Basing on that, the paper firstly indicated that the immunity system could be regarded as a composite indicator. Secondly, the paper gave the specific definition of the composite immunity indicator (CII), and discussed the methods of calculation, especially provided two calculation methods of the weights, that is, the Analytic Hierarchy Process (AHP) and the Principal Component Analysis (PCA). Finally, examples were given to clarify the specific steps to compute the composite immunity indicator. The computing results gave the quantitative evaluation, which were in concordance with the existing conclusions.

Catalytic Role of Cu Sites of Cu/MCM-41 in Phenol Hydroxylation

Langmuir : the ACS Journal of Surfaces and Colloids. Jan, 2010  |  Pubmed ID: 19938803

Four types of copper-containing MCM-41 mesoporous silicas were synthesized by the surface organometallic chemistry (SOMC) procedure (Cu/MCM-41-S), mechanical mixing (Cu/MCM-41-M), impregnation (Cu/MCM-41-I), and the hydrothermal technique (Cu/MCM-41-H). The resultant samples were characterized in detail by X-ray diffraction (XRD), N(2) physical adsorption, transmission electron microscopy (TEM), UV-vis diffuse reflectance spectroscopy (UV-vis DRS), temperature-programmed reduction (TPR), and infrared spectroscopy (IR) of NO adsorption. Catalytic behaviors of these samples for hydroxylation of phenol with H(2)O(2) were evaluated. The results revealed that depending on the preparation methods the samples contain different copper-oxo species and thus show different catalytic behaviors. Among these samples, the one prepared by SOMC contains a predominant amount of isolated Cu(2+) and exhibits the most excellent catalytic activity and selectivity. The amount of isolated copper species decreases in the order of Cu/MCM-41-S > Cu/MCM-41-H > Cu/MCM-41-I > Cu/MCM-41-M, while the amount of copper oxide clusters increases in a reversal order. The difference in the catalytic activity and product selectivity of these four samples could be rationally explained by the distinction of chemical states of copper species. The highly dispersed isolated Cu(2+) species are identified as the active sites in the phenol hydroxylation, while the nonisolated Cu(2+) clusters or oxide are responsible for the deep oxidation of primary product HQ and the decrease of product selectivity. The mechanism of the copper-catalyzed phenol hydroxylation was proposed.

Metal Coordination Mediated Reversible Conversion Between Linear and Cross-linked Supramolecular Polymers

Angewandte Chemie (International Ed. in English). Feb, 2010  |  Pubmed ID: 20052699

A Novel Solution-phase Approach to Nanocrystalline Niobates: Selective Syntheses of Sr0.4H1.2Nb2O6.H2O Nanopolyhedrons and SrNb2O6 Nanorods Photocatalysts

Chemical Communications (Cambridge, England). Mar, 2010  |  Pubmed ID: 20162143

A novel solution-phase route using Nb(2)O(5).nH(2)O as precursor was developed to selectively synthesize single-crystalline Sr(0.4)H(1.2)Nb(2)O(6).H(2)O nanopolyhedrons and SrNb(2)O(6) nanorods photocatalysts via simply adjusting pH values of the reactive solutions.

The BHLH Transcription Factor CHF1/Hey2 Regulates Susceptibility to Apoptosis and Heart Failure After Pressure Overload

American Journal of Physiology. Heart and Circulatory Physiology. Jun, 2010  |  Pubmed ID: 20382855

Cardiac hypertrophy is a common response to hemodynamic stress in the heart and can progress to heart failure. To investigate whether the transcription factor cardiovascular basic helix-loop-helix factor 1/hairy/enhancer of split related with YRPW motif 2 (CHF1/Hey2) influences the development of cardiac hypertrophy and progression to heart failure under conditions of pressure overload, we performed aortic constriction on 12-wk-old male wild-type (WT) and heterozygous (HET) mice globally underexpressing CHF1/Hey2. After aortic banding, WT and HET mice showed increased cardiac hypertrophy as measured by gravimetric analysis, as expected. CHF1/Hey2 HET mice, however, demonstrated a greater increase in the ventricular weight-to-body weight ratio compared with WT mice (P < 0.05). Echocardiographic measurements showed a significantly decreased ejection fraction compared with WT mice (P < 0.05). Histological examination of Masson trichrome-stained heart tissue demonstrated extensive fibrosis in HET mice compared with WT mice. TUNEL staining demonstrated increased apoptosis in HET hearts (P < 0.05). Exposure of cultured neonatal myocytes from WT and HET mice to H(2)O(2) and tunicamycin, known inducers of apoptosis that work through different mechanisms, demonstrated significantly increased apoptosis in HET cells compared with WT cells (P < 0.05). Expression of Bid, a downstream activator of the mitochondrial death pathway, was expressed in HET hearts at increased levels after aortic banding. Expression of GATA4, a transcriptional activator of cardiac hypertrophy, was also increased in HET hearts, as was phosphorylation of GATA4 at Ser(105). Our findings demonstrate that CHF1/Hey2 expression levels influence hypertrophy and the progression to heart failure in response to pressure overload through modulation of apoptosis and GATA4 activity.

Anion-assisted Complexation of Paraquat by Cryptands Based on Bis(m-phenylene)-[32]crown-10

Chemistry (Weinheim an Der Bergstrasse, Germany). May, 2010  |  Pubmed ID: 20391577

The complexation of tightly ion-paired divalent salts such as paraquat dichloride by cryptands based on crown ethers can be improved by the introduction of ion-pair recognition as a means of also binding the counteranions. A series of diamide-based cryptands derived from bis(m-phenylene)-[32]crown-10 and designed to complex the bipyridinium dication with anion assistance was synthesized. The ion-pair recognition process was fully characterized by (1)H NMR spectroscopy, UV/Vis spectroscopy, electrospray ionization mass spectrometry and single crystal X-ray analysis. (1)H NMR spectroscopy demonstrated that these new heteroditopic cryptand hosts can complex both the positive and negative components of the paraquat dichloride salt. UV/Vis spectroscopy showed that the addition of chloride anion into equimolar solutions of cryptands 3c or 3g with paraquat bis(hexafluorophosphate) salt (2a) improves the binding of the cryptands to the paraquat guest. Electrospray ionization mass spectrometry and single-crystal X-ray analysis confirmed the 1:1 stoichiometries and ion-pair recognition of these cryptand/paraquat complexes. It was found that the cryptand 3g, with 13 atoms and an isophthalamide moiety in the third chain, exhibited the best binding affinity for tightly ion-paired paraquat dichloride (2b), due to the combination of its spatial compatibility and additional anion-binding site.

Geometry and Efficacy of Cross-strand Trp/Trp, Trp/Tyr, and Tyr/Tyr Aromatic Interaction in a Beta-hairpin Peptide

Biochemistry. Jun, 2010  |  Pubmed ID: 20423111

The Trpzip2 peptide (WTWENGKWTWK-NH(2)), designed by Cochran and co-workers, contains two pairs of Trp's having cross-strand interaction and forms a stable antiparallel beta-hairpin. In order to study the geometries and effects on the structure and stability of different aromatic interactions, selected tryptophan residues were substituted with Tyr to get three Trpzip2 mutants with different Trp/Trp, Trp/Tyr, and Tyr/Tyr interacting pairs. Their native-state structures were determined using two-dimensional (2D) NMR and shown to have the same cross-strand edge-to-face Trp/Trp interaction as that in Trpzip2 for the Trp/Trp pair. The analogous Trp/Tyr and Tyr/Tyr pairs also tended to have an edge-to-face geometry. The effects of specific Trp/Trp, Trp/Tyr, and Tyr/Tyr interactions on hairpin stability were studied by varying temperature and monitoring structure with electronic circular dichroism (CD) and infrared (IR) absorption spectra. IR and CD temperature variations were fit to a two-state model that yielded lower T(m) values for Tyr containing mutants, indicating that Trp/Tyr and Tyr/Tyr interactions have less contribution to hairpin stability than the Trp/Trp interaction. Trp/Tyr interactions can provide significant stabilization, much greater than the Trp/aliphatic interaction, but Tyr/Tyr interactions are not as significant. Cross-strand interacting residues involving Trp with an edge-to-face orientation with Trp or Tyr had the strongest impact on hairpin stability.

Comparative Analysis of Immune Responses Induced by Vaccination with SIV Antigens by Recombinant Ad5 Vector or Plasmid DNA in Rhesus Macaques

Molecular Therapy : the Journal of the American Society of Gene Therapy. Aug, 2010  |  Pubmed ID: 20551910

DNA vaccines have undergone important enhancements in their design, formulation, and delivery process. Past literature supports that DNA vaccines are not as immunogenic in nonhuman primates as live vector systems. The most potent recombinant vector system for induction of cellular immune responses in macaques and humans is adenovirus serotype 5 (Ad5), an important benchmark for new vaccine development. Here, we performed a head-to-head evaluation of the Merck Ad5 SIV vaccine and an optimized electroporation (EP) delivered SIV DNA vaccine in macaques. Animals receiving the Ad5 vaccine were immunized three times, whereas the DNA-vaccinated animals were immunized up to four times based on optimized protocols. We observed significant differences in the quantity of IFNgamma responses by enzyme-linked immunosorbent spot (ELISpot), greater proliferative capacity of CD8(+) T cells, and increased polyfunctionality of both CD4(+) and CD8(+) T cells in the DNA-vaccinated group. Importantly, Ad5 immunizations failed to boost following the first immunization, whereas DNA responses were continually boosted with all four immunizations demonstrating a major advantage of these improved DNA vaccines. These optimized DNA vaccines induce very different immune phenotypes than traditional Ad5 vaccines, suggesting that they could play an important role in vaccine research and development.

Human Pro-islet Amyloid Polypeptide (ProIAPP(1-48)) Forms Amyloid Fibrils and Amyloid Spherulites in Vitro

Journal of Inorganic Biochemistry. Oct, 2010  |  Pubmed ID: 20579740

Deposition of beta sheets of islet amyloid polypeptide (IAPP) in pancreatic tissue is implicated in the aetiology of type 2 diabetes mellitus (T2DM). IAPP is cleaved from its precursor protein, pro-islet amyloid polypeptide (ProIAPP) and incomplete cleavage results in ProIAPP(1-48), which is found co-deposited with IAPP. Cu(II) prevents IAPP from forming amyloid and herein we investigated if it would also prevent ProIAPP(1-48) from forming beta sheets. Excess Cu(II) prevented ProIAPP(1-48) from forming amyloid and additionally reversed the formation of beta sheets in pre-formed fibrils of the peptide. The latter was also true for ProIAPP(1-48) fibrils formed in the presence of Al(III). An unexpected finding was the formation of spherulites of ProIAPP(1-48) which were only observed in preparations which included Al(III). The spherulites were 40-100 microm in diameter and stained positively for Al(III) suggesting a role for this metal in their formation. The abolition by Cu(II) of the propensity of ProIAPP(1-48) to form amyloid may have important implications for the treatment of T2DM. The immediate significance for diabetes of the equally novel observation of spherulites of ProIAPP(1-48) is unknown though, as with spherulites of Abeta(42) in Alzheimer's disease, there may be implications for the aetiology of the disease.

Clinicopathologic Characteristics of 12 Patients with Vulvar Sweat Gland Carcinoma

International Journal of Gynecological Cancer : Official Journal of the International Gynecological Cancer Society. Jul, 2010  |  Pubmed ID: 20606537

The aim of this article was to evaluate the clinical and pathologic characteristics, therapy, and prognostic factors of vulvar sweat gland carcinoma.

Sr(0.4)H(1.2)Nb(2)O(6)·H(2)O Nanopolyhedra: an Efficient Photocatalyst

Nanoscale. Oct, 2010  |  Pubmed ID: 20820646

A photocatalyst Sr(0.4)H(1.2)Nb(2)O(6)·H(2)O (HSN) nanopolyhedra with high surface area has been successfully prepared by a simple hydrothermal method. The as-prepared samples were characterized by XRD, BET, SEM, TEM and XPS. The electronic structure of HSN determined by DFT calculations and electrochemical measurement revealed that HSN is an indirect-bandgap and n-type semiconductor, respectively. HSN samples showed high photocatalytic activities for both pure water splitting and the decomposition of benzene. The rate of H(2) evolution over HSN was 15 times higher than that of P25 and the conversion ratio of benzene exceeded twice that of P25. The photocatalytic activities for water splitting can be greatly improved by loading various co-catalysts on HSN, such as Au, Pt, and Pd. The photocatalytic mechanisms were proposed based on the band structure and characterization results of the photocatalyst.

Berberine Attenuates CAMP-induced Lipolysis Via Reducing the Inhibition of Phosphodiesterase in 3T3-L1 Adipocytes

Biochimica Et Biophysica Acta. Apr, 2011  |  Pubmed ID: 20969954

Berberine, a hypoglycemic agent, has been shown to decrease plasma free fatty acids (FFAs) level in insulin-resistant rats. In the present study, we explored the mechanism responsible for the antilipolytic effect of berberine in 3T3-L1 adipocytes. It was shown that berberine attenuated lipolysis induced by catecholamines, cAMP-raising agents, and a hydrolyzable cAMP analog, but not by tumor necrosis factor α and a nonhydrolyzable cAMP analog. Unlike insulin, the inhibitory effect of berberine on lipolysis in response to isoproterenol was not abrogated by wortmannin, an inhibitor of phosphatidylinositol 3-kinase, but additive to that of PD98059, an extracellular signal-regulated kinase kinase inhibitor. Prior exposure of adipocytes to berberine decreased the intracellular cAMP production induced by isoproterenol, forskolin, and 3-isobutyl-1-methylxanthine (IBMX), along with hormone-sensitive lipase (HSL) Ser-563 and Ser-660 dephosphorylation, but had no effect on perilipin phosphorylation. Berberine stimulated HSL Ser-565 as well as adenosine monophosphate-activated protein kinase (AMPK) phosphorylation. However, compound C, an AMPK inhibitor, did not reverse the regulatory effect of berberine on HSL Ser-563, Ser-660, and Ser-565 phosphorylation, nor the antilipolytic effect of berberine. Knockdown of AMPK using RNA interference also failed to restore berberine-suppressed lipolysis. cAMP-raising agents increased AMPK activity, which was not additive to that of berberine. Stimulation of adipocytes with berberine increased phosphodiesterase (PDE) 3B and PDE4 activity measured by hydrolysis of (3)[H]cAMP. These results suggest that berberine exerts an antilipolytic effect mainly by reducing the inhibition of PDE, leading to a decrease in cAMP and HSL phosphorylation independent of AMPK pathway.

Pou3f4 Deficiency Causes Defects in Otic Fibrocytes and Stria Vascularis by Different Mechanisms

Biochemical and Biophysical Research Communications. Jan, 2011  |  Pubmed ID: 21144821

DFN3, the most prevalent X-linked hearing loss, is caused by mutations in the POU3F4 gene. Previous studies in Pou3f4 knockout mice suggest that defective otic fibrocytes in the spiral ligament of the cochlear lateral wall may underlie the hearing loss in DFN3. To better understand the pathological mechanisms of the DFN3 hearing loss, we analyzed inner ears of Pou3f4-deficient mice during development. Our results indicate that compartmentalization of the spiral ligament mesenchyme setting up boundaries for specific otic fibrocytes occurs normally in Pou3f4-deficient cochlea. However, differentiation of the compartmentalized mesenchyme into specific otic fibrocytes was blocked in the absence of Pou3f4 function. In addition, we found that stria vascularis in the cochlear lateral wall was also affected in Pou3f4-deficient cochlea. Unlike the otic fibrocytes, differentiation of stria vascularis was completed in the absence of Pou3f4 function, yet expression of Kir4.1 channels in the strial intermediate cells, essential for the sound transduction, was lost afterwards. These results suggest that Pou3f4 deficiency causes defects in both otic fibrocytes and stria vascularis at different developmental stages and by different pathological mechanisms, which may account for the progressive nature of DFN3 hearing loss.

Multivalent Smallpox DNA Vaccine Delivered by Intradermal Electroporation Drives Protective Immunity in Nonhuman Primates Against Lethal Monkeypox Challenge

The Journal of Infectious Diseases. Jan, 2011  |  Pubmed ID: 21148501

The threat of a smallpox-based bioterrorist event or a human monkeypox outbreak has heightened the importance of new, safe vaccine approaches for these pathogens to complement older poxviral vaccine platforms. As poxviruses are large, complex viruses, they present technological challenges for simple recombinant vaccine development where a multicomponent mixtures of vaccine antigens are likely important in protection. We report that a synthetic, multivalent, highly concentrated, DNA vaccine delivered by a minimally invasive, novel skin electroporation microarray can drive polyvalent immunity in macaques, and offers protection from a highly pathogenic monkeypox challenge. Such a diverse, high-titer antibody response produced against 8 different DNA-encoded antigens delivered simultaneously in microvolumes has not been previously described. These studies represent a significant improvement in the efficiency of the DNA vaccine platform, resulting in immune responses that mimic live viral infections, and would likely have relevance for vaccine design against complex human and animal pathogens.

A General Templated Method to Homogeneous and Composition-tunable Hybrid TiO2 Nanocomposite Fibers

Chemical Communications (Cambridge, England). Mar, 2011  |  Pubmed ID: 21225065

Sequential impregnations of metal ions and titanium tetraisopropoxide (TTIP) into activated carbon fibers (ACF) followed by a solvothermal treatment has been found to be a general method in the preparations of homogeneous and composition-tunable hybrid TiO(2) hierarchical nanocomposite fibers like WO(3)/TiO(2), Fe(2)O(3)/TiO(2) and SnO(2)/TiO(2).

Synthesis and Antitumor Activity of Novel Ribonucleosides with C-5 OH Replaced by a Diaminopyrimidinyl Group

Bioorganic & Medicinal Chemistry Letters. Feb, 2011  |  Pubmed ID: 21227689

A series of novel ribonucleosides with C-5 OH replaced by a diaminopyrimidinyl group were synthesized by successively nucleophilic substitutions of 5'-deoxy-5'-amino-ribonucleosides with 2,4-dichloropyrimidine and then with various fatty amines under microwave irradiation. Their anticancer activities in vitro were preliminarily evaluated. Compounds 7a and 8a only exhibited anticancer activity against A549 cell line with the IC(50) values of 10.73 and 10.99 μM, respectively. In addition, 7h and 8h showed potent activities against both A549 and Hela cell lines with the IC(50) values of 12.71, 8.55 and 8.44, 5.55 μM, respectively.

Trophic Effects of Mesenchymal Stem Cells Increase Chondrocyte Proliferation and Matrix Formation

Tissue Engineering. Part A. May, 2011  |  Pubmed ID: 21247341

Previous studies showed that coculture of primary chondrocytes (PCs) with various sources of multipotent cells results in a higher relative amount of cartilage matrix formation than cultures containing only chondrocytes. The aim of this study was to investigate the mechanism underlying this observation. We used coculture pellet models of human mesenchymal stem cells (hMSCs) and human PCs or bovine PCs (bPCs) and studied the fate and the contribution to cartilage formation of the individual cell populations during coculture. Enhanced cartilage matrix deposition was confirmed by histology and quantification of total glycosaminoglycan deposition. Species-specific quantitative polymerase chain reaction demonstrated that cartilage matrix gene expression was mainly from bovine origin when bPCs were used. Short tandem repeat analysis and species-specific quantitative polymerase chain reaction analysis of genomic DNA demonstrated the near-complete loss of MSCs in coculture pellets after 4 weeks of culture. In coculture pellets of immortalized MSCs and bPCs, chondrocyte proliferation was increased, which was partly mimicked using conditioned medium, and simultaneously preferential apoptosis of immortalized MSCs was induced. Taken together, our data clearly demonstrate that in pellet cocultures of MSCs and PCs, the former cells disappear over time. Increased cartilage formation in these cocultures is mainly due to a trophic role of the MSCs in stimulating chondrocyte proliferation and matrix deposition by chondrocytes rather than MSCs actively undergoing chondrogenic differentiation.

Multiple Effects of Benzamide Antibiotics on FtsZ Function

Molecular Microbiology. Apr, 2011  |  Pubmed ID: 21276094

Cell division in almost all bacteria is orchestrated by the essential tubulin homologue FtsZ, which assembles into a ring-like structure and acts as a scaffold for the division machinery. Division was recently validated as an important target for antibiotics by the demonstration that low-molecular-weight inhibitors of FtsZ, called benzamides, can cure mice infected with Staphylococcus aureus. In treated cells of Bacillus subtilis we show that FtsZ assembles into foci throughout the cell, including abnormal locations at the cell poles and over the nucleoid. These foci are not inactive aggregates because they remain dynamic, turning over almost as rapidly as untreated polymers. Remarkably, although division is completely blocked, the foci efficiently recruit division proteins that normally co-assemble with FtsZ. However, they show no affinity for components of the Min or Nucleoid occlusion systems. In vitro, the benzamides strongly promote the polymerization of FtsZ, into hyperstable polymers, which are highly curved. Importantly, even at low concentrations, benzamides transform the structure of the Z ring, resulting in abnormal helical cell division events. We propose that benzamides act principally by promoting an FtsZ protomer conformation that is incompatible with a higher-order level of assembly needed to make a division ring.

Controlled Syntheses of Cubic and Hexagonal ZnIn2S4 Nanostructures with Different Visible-light Photocatalytic Performance

Dalton Transactions (Cambridge, England : 2003). Mar, 2011  |  Pubmed ID: 21290033

Cubic ZnIn(2)S(4) nanoparticles and hexagonal ZnIn(2)S(4) flower-like microspheres were controlled synthesized via a facile hydrothermal method by simply changing the metal precursors. The as-prepared samples were characterized by XRD, SEM, TEM and UV-vis DRS. It was found that the metal precursors influenced the final ZnIn(2)S(4) polymorphs, i.e., metal nitrates led to the formation of cubic ZnIn(2)S(4), while metal chlorides resulted in the formation of the hexagonal phase. The formation processes of the cubic ZnIn(2)S(4) nanoparticles and hexagonal ZnIn(2)S(4) flower-like microspheres were investigated and the mechanism of the phase formation was proposed. Although both cubic and hexagonal ZnIn(2)S(4) polymorphs exhibited photocatalytic activity for the degradation of methyl orange (MO) under visible light irradiation, the photocatalytic performances over cubic and hexagonal ZnIn(2)S(4) were different.

A 12-week, Double-masked, Parallel-group Study of the Safety and Efficacy of Travoprost 0.004% Compared with Pilocarpine 1% in Chinese Patients with Primary Angle-closure and Primary Angle-closure Glaucoma

Journal of Glaucoma. Aug, 2011  |  Pubmed ID: 21336155

To examine the intraocular pressure-lowering efficacy and safety of travoprost 0.004% and pilocarpine 1% in Chinese patients with primary angle-closure (PAC) and primary angle-closure glaucoma (PACG) after laser iridotomy in China.

Perturbation Analysis of the υ = 6 Level in the D3Δ State of CS Based on Its Near-infrared Absorption Spectrum

The Journal of Physical Chemistry. A. Apr, 2011  |  Pubmed ID: 21417295

The spectrum of CS was recorded in the region of 12,086-12,630 cm(-1) by employing optical heterodyne concentration modulation laser absorption spectroscopy. Nearly 350 transitions were assigned to the (6, 0) band in the d(3)Δ-a(3)Π system of CS. The overtone transitions of the (12, 0) band in the a(3)Π(2)-a(3)Π(0) transition were first observed due to the perturbation interaction between d(3)Δ(1) and a(3)Π(2). The Λ doubling in the a(3)Π(1) state was also resolved at high rotational levels. The molecular constants of the a(3)Π (υ = 0) and d(3)Δ (υ = 6) levels and the perturbation parameters of the d(3)Δ (υ = 6) level were determined through nonlinear least-squares fitting using effective hamiltonians. The calculations of mixing fractions of the perturbed states were performed in order to obtain precise information on the perturbations of the d(3)Δ (υ = 6) levels. The mechanisms for perturbations of d(3)Δ (υ = 6) with the a(3)Π (υ = 12) and A(1)Π (υ = 1) levels, especially for the second-order perturbation, were discussed and explained according to first-order nondegenerate perturbation theory.

Inter-ethnic Variation of Ocular Traits-design and Methodology of Comparison Study Among American Caucasians, American Chinese and Mainland Chinese

Yan Ke Xue Bao = Eye Science / "Yan Ke Xue Bao" Bian Ji Bu. Mar, 2011  |  Pubmed ID: 21425493

To summarize the design and methodology of a multi-center study. With the existed ethnic differences of glaucoma, this survey will explore the differences with regard to anterior and posterior ocular segment parameters between Caucasians and Chinese.

Differentially Expressed Genes in Men1 Knockout and Wild‑type Embryoid Bodies for Pancreatic Islet Development

Molecular Medicine Reports. Mar-Apr, 2011  |  Pubmed ID: 21468568

The Men1 gene has been identified as the gene responsible for MEN-1, a hereditary syndrome transmitted as an autosomal dominant trait. Disruption of the Men1 gene results in defects in the development of multiple organs, including pancreatic islets. Homozygous disruption of Men1 in mice causes embryonic lethality, making it difficult to determine the genes involved in defects of pancreatic islets during embryonic development. In this study, embryoid bodies formed from null mutant (Men1-/-) and wild-type (Men1+/+) embryonic stem cells were used as a model system to investigate the effects of the Men1 gene on pancreatic islet development. Using RT-PCR, SOX17, FOXA2 and NKX2.2 were found to be differentially expressed between the two embryoid bodies. Additionally, the gene expression profile of these Men1-/- embryoid bodies was characterized in detail by DNA microarray techniques, and a series of putative menin-targeted genes was identified. Our study suggests a critical role for Men1 in pancreatic islet development, and indicates that genes such as SOX17, FOXA2, NKX2.2 and SOX4 are potential targets of Men1.

Immune Response and Protective Efficacy Against Homologous Challenge in BALB/c Mice Vaccinated with DNA Vaccine Encoding Toxoplasma Gondii Actin Depolymerizing Factor Gene

Veterinary Parasitology. Jun, 2011  |  Pubmed ID: 21489695

A DNA vaccine (pVAX1-TgADF) encoding Toxoplasma gondii actin depolymerizing factor (ADF) gene was constructed and the immune response and protective efficacy of this vaccine against homologous challenge in BALB/c mice were evaluated. High titers of specific antibody and increases in the percentage of CD4(+) and CD8(+) T lymphocyte cells were observed from BALB/c mice vaccinated with pVAX1-TgADF (P<0.05), when PBS group was used as control. The survival time of BALB/c mice in pVAX1-TgADF group was longer than those in control groups. The numbers of brain cysts in the experimental BALB/c mice immunized with pVAX1-TgADF reduced significantly compared with those in PBS group (P<0.05), and the rate of reduction could reach to around 42.8%. These results suggested that the DNA vaccine pVAX1-TgADF could generate specific humoral and cellular immune responses, prolong survival times, and reduce brain cysts load against T. gondii infection in BALB/c mice.

IL-17 Receptor Signaling and T Helper 17-mediated Autoimmune Demyelinating Disease

Trends in Immunology. May, 2011  |  Pubmed ID: 21493143

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system (CNS). Experimental autoimmune encephalomyelitis (EAE) is widely used to dissect molecular mechanisms of MS and to develop new therapeutic strategies. The T helper 17 (Th17) subset of CD4 T cells plays a crucial role in the development of EAE. IL-17, a cytokine produced by Th17 cells, participates in EAE pathogenesis through induction of inflammatory gene expression in target cells. Recent work has shown that Act1, a U-box E3 ubiquitin ligase, is recruited to IL-17 receptor (IL-17R) upon IL-17 stimulation and is required for IL-17-mediated signaling. Here, we review the molecular and cellular mechanisms by which IL-17 and Act1-mediated signaling contribute to EAE.

A Facile Hydrothermal Method to BiSbO4 Nanoplates with Superior Photocatalytic Performance for Benzene and 4-chlorophenol Degradations

Dalton Transactions (Cambridge, England : 2003). Jun, 2011  |  Pubmed ID: 21519620

BiSbO(4) nanoplates with a large BET specific area has been prepared successfully via a facile hydrothermal reaction from Sb(2)O(3) and Bi(NO(3))(3). The effects of reaction conditions and the precursors on the final products were investigated. It is proposed that the redox reaction between Sb(2)O(3) and Bi(NO(3))(3) plays a pivotal role in the formation of nanocrystalline BiSbO(4). The hydrothermally prepared nanocrystalline BiSbO(4) was characterized by X-ray diffraction (XRD), N(2)-sorption BET surface area, UV-vis diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). The DRS result clarifies that BiSbO(4), originally believed to be a visible light responsive photocatalyst, is indeed UV light responsive with a band gap of 3.5 eV. The existence of Bi containing an impurity may be responsible for the visible light response of BiSbO(4) prepared via a conventional solid state reaction. BiSbO(4) nanoplates prepared via the hydrothermal method showed superior photocatalytic performance for the degradation of benzene and 4-chlorophenol (4-CP) as compared to BiSbO(4) prepared via a solid state reaction and Degussa P25. BiSbO(4(Hy)) nanoplates can be a promising photocatalyst in the treatment of environmental pollution.

Cartilage Tissue Engineering

Endocrine Development. 2011  |  Pubmed ID: 21865759

Cartilage tissue engineering is the art aimed at repairing defects in the articular cartilage which covers the bony ends in the joints. Since its introduction in the early 1990s of the past century, cartilage tissue engineering using ACI has been used in thousands of patients to repair articular cartilage defects. This review focuses on emerging strategies to improve cartilage repair by incorporating fundamental knowledge of developmental and cell biology in the design of optimized strategies for cell delivery at the defect site and to locally stimulate cartilage repair responses.

[The Clinical Study of High-frequency Ultrasound-guided Vacuum-assisted Biopsy for Breast Microcalcifications]

Zhonghua Wai Ke Za Zhi [Chinese Journal of Surgery]. Oct, 2011  |  Pubmed ID: 22321683

To evaluate the clinical application of high-frequency ultrasound-guided vacuum-assisted biopsy for breast microcalcifications.

Regulation of MMP10 Expression by the Transcription Factor CHF1/Hey2 is Mediated by Multiple E Boxes

Biochemical and Biophysical Research Communications. Dec, 2011  |  Pubmed ID: 22079635

The cardiovascular restricted bHLH transcription factor CHF1/Hey2 has been reported to play an important role in regulation of vascular smooth muscle phenotype and gene expression, but the downstream target genes that mediate these effects have not been completely elucidated. We have previously found that loss of CHF1/Hey2 in vascular smooth muscle cells leads to dysregulated expression of the matrix metalloproteinase gene MMP10 after treatment with PDGF. Here we report that loss or knockdown of CHF1/Hey2 in vascular smooth muscle cells leads to increased expression and activity of MMP10 at baseline, suggesting a direct effect of CHF1/Hey2 on MMP10 promoter regulation. To test this hypothesis, we assessed the effects of CHF1/Hey2 on a 2.5 kb MMP10 promoter region upstream of the transcriptional start site. We found that this region contains multiple elements including 12 E-boxes that mediate constitutive activity and repression by CHF1/Hey2 in 293T cells and A7r5 smooth muscle cells. Surprisingly, mutation of these E-boxes not only abolished CHF1/Hey2 repression, but also diminished constitutive expression. In addition, we observed that some of these mutations unmasked an activator function for CHF1/Hey2, which has not been previously described. These findings support the hypothesis that CHF1/Hey2 is an important regulator of MMP10 expression.

Self-assembled 3D Architectures of Bi2TiO4F2 As a New Durable Visible-light Photocatalyst

Nanoscale. Jan, 2012  |  Pubmed ID: 22095258

A new hierarchical visible-light-driven photocatalyst Bi(2)TiO(4)F(2) was synthesized by a solvothermal method for the first time. The photocatalyst was characterized by X-ray powder diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), N(2) adsorption-desorption (BET), UV-vis diffuse reflectance spectroscopy (DRS). Such hierarchical Bi(2)TiO(4)F(2) microspheres assembled by nanosheets were fabricated via an Ostwald ripening process in the absence of soft templates (surfactants). The as-prepared samples' bimodal pore-size distributions in the mesoporous region consisted of smaller intra-aggregated pores with peak pore diameter of ca. 4.6 nm and larger inter-aggregated pores with peak pore diameter of ca. 17.0 nm. The band gap of the obtained Bi(2)TiO(4)F(2) was estimated to be about 2.71-3.06 eV for various solvothermal treatment time. Owing to the hierarchical structure with bimodal pores, low band gaps and high crystallinity, the Bi(2)TiO(4)F(2) microspheres exhibited high photocatalytic performance and durability for the degradation of rhodamine B (RhB) under visible light (> 420 nm). It was proved that the photo-generated holes and ˙OH radicals played an essential role for the oxidation of RhB.

The Effect of Group IIIA Metal Ion Dopants on the Photocatalytic Activities of Nanocrystalline Sr0.25H1.5Ta2O6·H2O

Physical Chemistry Chemical Physics : PCCP. Jan, 2012  |  Pubmed ID: 22130094

A series of group IIIA metal ion electron acceptors doped into Sr(0.25)H(1.5)Ta(2)O(6)·H(2)O (HST) samples have been prepared by an impregnation and calcination method for the first time. The samples are characterized by XRD, TEM, DRS and XPS. The variations in the electronic structure and photoelectric response after metal ion doping are investigated by theoretical calculations and photocurrent experiments, respectively. Results show that the metal ions can be efficiently incorporated into the HST crystal structure, which is reflected in the lattice contraction. Meanwhile, the photoabsorption edges of the metal-doped HST samples are red shifted to a longer wavelength. Taking into account the ionic radii and electronegativities of the dopants, as well as the XRD and XPS results, it is concluded that Ta(5+) ions may be partially substituted by the Al(3+) and Ga(3+) ions in the framework, while In(3+) ions are the favourable substitutes for Sr(2+) sites in the cavity. The first-principles DFT calculations confirm that the variation of the band structure is sensitive to the type of group IIIA metal ion. Introducing the dopant only at the Ta site induces an obvious variation in the band structure and the band gap becomes narrow. Meanwhile, an ''extra step'' appeared in the band gap, which can trap photogenerated electrons from the valance band (VB) and could enhance the charge mobility and the photocurrent. For the photocatalytic degradation of methyl orange in an aqueous solution and in benzene in the gas phase, the doped samples show superior photocatalytic activities compared with both undoped samples and TiO(2). The enhanced photocatalytic activities can be well explained by their electronic structure, photoabsorption performance, photoelectric response, and the concentration of the active species. Due to the fact that Ga ion doping can create an acceptor impurity level and change the electronic band, efficiently narrowing the band gap, the Ga-doped sample shows the highest photocatalytic activity.

Glucose-mediated Repression of Menin Promotes Pancreatic β-cell Proliferation

Endocrinology. Feb, 2012  |  Pubmed ID: 22166975

Menin, encoded by the Men1 gene, is responsible for β-cell tumor formation in patients with multiple endocrine neoplasia type 1. Recently, menin has been proven to negatively regulate β-cell proliferation during pregnancy. However, it is unclear whether menin is involved in pancreatic β-cell proliferation in response to other physiological replication stimuli, such as glucose. In this study, we found that the menin level was significantly reduced in high glucose-treated INS1 cells and primary rat islets, both with increased proliferation. A similar observation was found in islets isolated from rats subjected to 72-h continuous glucose infusion. The glucose-induced proliferation was inhibited by menin overexpression. Further molecular studies showed that glucose-induced menin suppression was blocked by PI3K/Akt pathway inhibitors. A major PI3K/Akt substrate, Foxo1, was shown to enhance menin transcription levels by binding the promoter region of the Men1 gene. Therefore, we conclude that glucose inhibits menin expression via the PI3K/Akt/Foxo1 pathway and hence promotes pancreatic β-cell proliferation. Our study suggests that menin might serve as an important intracellular target of glucose to mediate the mitogenic effect that glucose exerts in pancreatic β-cells.

Design, Synthesis and Anti-fibrosis Activity Study of N₁-substituted Phenylhydroquinolinone Derivatives

Molecules (Basel, Switzerland). 2012  |  Pubmed ID: 22301723

Pirfenidone (5-methyl-1-phenyl-2(1H)-pyridone, PFD) is a small-molecule compound acting on multiple targets involved in pathological fibrogenesis and is effective to increase the survival of patients with fibrosis, such as idiopathic pulmonary fibrosis. However, PFD is not active enough, requiring a high daily dose. In this study, to keep the multiple target profiles, N₁-substituted phenylhydroquinolinone derivatives, which retain the 1-phenyl-2(1H)-pyridone scaffold were designed and synthesized. The preliminary anti-fibrosis activities for all target compounds were evaluated on a NIH3T3 fibroblast cell line using MTT assay methods. Most compounds showed significant inhibition on NIH3T3 cell proliferation with a IC₅₀ range of 0.09-26 mM, among which 5-hydroxy-1-(4'-bromophenyl)-5,6,7,8-tetrahydroquinolin-2(1H)-one (6j) displayed 13 times higher potency (IC₅₀ = 0.3 mM) than that of AKF-PD (IC₅₀ = 4.2 mM). These results suggest that N₁-substituted phenylhydroquinolinone is a promising scaffold which can be applied for further investigation and for developing novel anti-fibrosis agents.

Effects of Noninvasive Electroacupuncture at Hegu (LI4) and Sanyinjiao (SP6) Acupoints on Dysmenorrhea: a Randomized Controlled Trial

Journal of Alternative and Complementary Medicine (New York, N.Y.). Feb, 2012  |  Pubmed ID: 22339102

This study aimed to evaluate the effects of noninvasive acupoint stimulation therapy with middle-frequency electrical waves on dysmenorrhea in young women.

Trophic Effects of Mesenchymal Stem Cells in Chondrocyte Co-cultures Are Independent of Culture Conditions and Cell Sources

Tissue Engineering. Part A. Mar, 2012  |  Pubmed ID: 22429306

Previously we have shown that the increased cartilage production in pellet co-cultures of chondrocytes and bone marrow derived mesenchymal stem cells (BM-MSCs) is due to a trophic role of the MSC in stimulating chondrocyte proliferation and matrix production rather than MSCs actively undergoing chondrogenic differentiation. These studies were performed in culture medium that was not compatible with chondrogenic differentiation of MSCs. In this study, we tested whether the trophic role of the MSCs is dependent on culturing co-culture pellets in medium compatible with chondrogenic differentiation of MSCs. In addition, we investigated whether the trophic role of the MSCs is dependent on their origins or is a more general characteristic of MSCs. Human BM-MSCs and bovine primary chondrocytes (bPCs) were co-cultured in medium compatible with chondrogenic differentiation of MSCs. Enhanced matrix production was confirmed by glycosaminoglycans (GAG) quantification. Species specific quantitative PCR (qPCR) demonstrated that cartilage matrix was mainly from bovine origin, indicative of a lack of chondrogenic differentiation of MSCs. In addition, pellet co-cultures were overgrown by bovine cells over time. To test the influence of origin on MSCs' trophic effects, MSCs isolated from adipose tissue and synovial membrane were co-cultured with human primary chondrocytes (hPCs) and their activity was compared with BM-MSCs, which served as control. GAG quantification again confirmed increased cartilage matrix production, irrespective of the source of the MSCs. EdU staining combined with cell tracking revealed increased proliferation of chondrocytes under each condition. Irrespective of the MSC source, short tandem repeat (STR) analysis of genomic DNA showed a decrease in MSCs in co-culture over time. Our results clearly demonstrate that in co-culture pellets MSCs stimulate cartilage formation due to a trophic effect on chondrocytes rather than differentiating into chondrocytes, irrespective of culture condition or origin. This implies that the trophic effect of MSCs in co-cultures is a general phenomenon with potential implications for use in cartilage repair strategies.

Vitreous Amyloidosis in Two Large Mainland Chinese Kindreds Resulting from Transthyretin Variant Lys35Thr and Leu55Arg

Ophthalmic Genetics. Mar, 2012  |  Pubmed ID: 21843040

To describe the clinical and pathological findings of two large mainland Chinese kindreds with vitreous amyloidosis and associated transthyretin mutation.

Function of Act1 in IL-17 Family Signaling and Autoimmunity

Advances in Experimental Medicine and Biology. 2012  |  Pubmed ID: 21948371

The maintenance of immune homeostasis requires the delicate balance between response to foreign antigens and tolerance to self. As such, when this balance is disrupted, immunodeficiency or autoimmunity may manifest. The adaptor molecule known as Act1 is a critical mediator of IL-17 receptor receptor family signaling. This chapter will detail the current understanding of Act1 's role in signal transduction as well as address the fundamental role of Act1 in autoimmunity. At the molecular level Act1 interacts with IL-17 R through the conserved SEFIR domain, binds TRAF proteins and exerts E3 ubiquitin ligase activity. In in vivo models, Act1 deficiency provides protection against experimental autoimmune diseases, such as colitis and EAE. Yet mice lacking in Act1 develop spontaneous autoimmune diseases. Indeed, the utility of Act1 seems to rely on the specific cell type expression that may determine the pathway that Act1 mediates.

Role of Different β-turns in β-hairpin Conformation and Stability Studied by Optical Spectroscopy

Proteins. Jan, 2012  |  Pubmed ID: 21989967

Model β-hairpin peptides based on variations in the turn sequence of Cochran's tryptophan zipper peptide, SWTWENGKWTWK, were studied using electronic circular dichroism (ECD), fluorescence, and infrared (IR) spectroscopies. The trpzip2 Asn-Gly turn sequence was substituted with Thr-Gly, Aib-Gly, (D)Pro-Gly, and Gly-Asn (trpzip1) to study the impact of turn stability on β-hairpin formation. Stability and conformational changes of these hairpins were monitored by thermodynamic analyses of the temperature variation of both FTIR (amide I') and ECD spectral intensities. These changes were fit to a two-state model which yielded different T(m) values, representing the folding/unfolding process, for hairpins with different β-turns. Different β-turns show systematic contributions to hairpin structure formation, and their inclusion in hairpin design can modify the folding pathways. Aib-Gly or (D)Pro-Gly sequences stabilize the turn resulting in residual Trp-Trp interaction at high temperatures, but at the same time the β-structure (cross strand H-bonds) can become less stable due to constraints of the turn, as seen for (D)Pro-Gly. The structure of the Aib-Gly turn containing hairpin was determined by NMR and was shown to be like trpzip2 (Asn-Gly turn) as regards turn and strand geometries, but to differ from trpzip1 (Gly-Asn turn). The Munoz and Eaton statistical mechanically derived multistate model, tested as an alternate point of view, represented contributions from H-bonds and hydrophobic interactions as well as conformational change as interdependent. Use of different spectral methods that vary in dependence on these physical interactions along with the structural variations provided insight to the complex folding pathways of these small, well-folded peptides.

Nucleoid Occlusion and Bacterial Cell Division

Nature Reviews. Microbiology. Jan, 2012  |  Pubmed ID: 22020262

The bacterial cell cycle requires the tight regulation and precise coordination of several sophisticated cellular processes. Prominent among them is the formation of the dividing wall or septum, which has to take place at the right time and place to ensure equality of the progeny and integrity of the genome. Nucleoid occlusion is a defence mechanism that prevents the chromosome from being bisected and broken by the division septum. It does so by preventing Z ring formation near the nucleoid, which also helps to determine the location of septation.

Nuclear Estrogen Receptor-mediated Notch Signaling and GPR30-mediated PI3K/AKT Signaling in the Regulation of Endometrial Cancer Cell Proliferation

Oncology Reports. Feb, 2012  |  Pubmed ID: 22075757

To elucidate the mechanisms of nuclear estrogen receptor (ER)-mediated and G protein-coupled receptor 30 (GPR30)-mediated signaling in the regulation of proliferation in ER-positive and ER-negative endometrial cancer cells, two human endometrial carcinoma cell lines, Ishikawa (ER-positive) and KLE (ER-negative), were used. PCR and Western blot analyses were used to determine the effects of estrogen stimulation on the activation of Notch and GPR30-PI3K/AKT signaling. Cell growth was investigated using MTT assays. Overexpression of ER in ER-negative cells was achieved by plasmid transfection and was used to investigate the effects on cellular growth and Notch signaling. GPR30-mediated signaling was evaluated using siRNA interference. Estrogen stimulated cell proliferation in both cell lines, it activated Notch signaling in ER-positive Ishikawa cells, but not in ER-negative KLE cells. Blockade of this signaling by a Notch inhibitor resulted in partial arrest of estrogen-induced cell proliferation in Ishikawa cells. Overexpression of ER in KLE cells restored estrogen-enhanced Notch signaling and further promoted cell growth. GPR30, as a new G-protein-coupled estrogen receptor, was detected in both cell lines, but was stronger in ER-negative KLE cells. Depletion of GPR30 in KLE cells abolished estrogen-induced PI3K/AKT signaling activation and resulted in inhibition of cell proliferation. Conclusively, regulation of proliferation in nuclear ER-positive endometrial cancer cells is mediated by both ER-Notch signaling and GPR30-PI3K/AKT signaling, whereas only the latter pathway is involved in the regulation of growth in nuclear ER-negative endometrial cancer cells.