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Find video protocols related to scientific articles indexed in Pubmed.
Human Phosphoglycerate Dehydrogenase Produces the Oncometabolite d-2-Hydroxyglutarate.
ACS Chem. Biol.
PUBLISHED: 11-19-2014
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Human d-3-phosphoglycerate dehydrogenase (PHGDH), the first enzyme in the serine biosynthetic pathway, is genomically amplified in tumors including breast cancer and melanoma. In PHGDH-amplified cancer cells, knockdown of PHGDH is not fully rescued by exogenous serine, suggesting possible additional growth-promoting roles for the enzyme. Here we show that, in addition to catalyzing oxidation of 3-phosphoglycerate, PHGDH catalyzes NADH-dependent reduction of ?-ketoglutarate (AKG) to the oncometabolite d-2-hydroxyglutarate (d-2HG). Knockdown of PHGDH decreased cellular 2HG by approximately 50% in the PHGDH-amplified breast cancer cell lines MDA-MB-468 (normal concentration 93 ?M) and BT-20 (normal concentration 35 ?M) and overexpression of PHGDH increased cellular 2HG by over 2-fold in non-PHGDH-amplified MDA-MB-231 breast cancer cells, which normally display very low PHGDH expression. The reduced 2HG level in PHGDH knockdown cell lines can be rescued by PHGDH re-expression, but not by a catalytically inactive PHGDH mutant. The initial connection between cancer and d-2HG involved production of high levels of d-2HG by mutant isocitrate dehydrogenase. More recently, however, elevated d-2HG has been observed in breast cancer tumors without isocitrate dehydrogenase mutation. Our results suggest that PHGDH is one source of this d-2HG.
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Platinum nanoparticles on porphyrin functionalized graphene nanosheets as a superior catalyst for methanol electrooxidation.
Nanoscale
PUBLISHED: 11-03-2014
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A novel nanostructured catalyst of platinum nanoparticles supported on 5,10,15,20-tetrakis(1-methyl-4-pyridinio)porphyrin tetra(p-toluenesulfonate) (TMPyP) functionalized graphene (TMPyP-graphene) is synthesized by the hydrothermal polyol process. The as-synthesized nanocomposites are characterized by Fourier transform infrared (FTIR) spectroscopy, UV-vis absorption spectroscopy, Raman spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and electrochemical tests. It has been found that Pt nanoparticles of ca. 3.4 nm are uniformly dispersed on the surface of TMPyP-graphene, and hold a high electrochemical active surface area (ECSA) of 126.2 m(2) g(-1). The results demonstrate that the Pt/TMPyP-graphene catalyst exhibits a much higher electrocatalytic activity and stability than the Pt/graphene and commercial Pt/C catalysts for methanol oxidation, which is of significant importance in improving the efficiency of Pt-based electrocatalysts for DMFCs applications.
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ROCK-dependent ATP5D modulation contributes to the protection of notoginsenoside NR1 against ischemia/reperfusion-induced myocardial injury.
Am. J. Physiol. Heart Circ. Physiol.
PUBLISHED: 10-12-2014
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Cardiac ischemia-reperfusion (I/R) injury remains a challenge for clinicians, which initiates with energy metabolism disorder. The present study was designed to investigate the protective effect of Notoginsenoside R1 (NR1) on I/R-induced cardiac injury and underlying mechanism. Male Sprague-Dawley rats were subjected to 30 min occlusion of left coronary anterior descending artery followed by reperfusion with or without NR1 pretreatment (5 mg/kg/hour). In vitro, H9c2 cells were cultured in oxygen and glucose deprivation/reoxygenation (OGD/R) condition after NR1 (0.1 mM), Rho kinase (ROCK) inhibitor Y-27632 (10 ?M) or RhoA/ROCK activator U-46619 (10 nM) administration. Myocardial infarct size, myocardial histology and cardiac function were evaluated. Myo?bril and mitochondria morphology were observed by transmission electron microscopy. F-actin and apoptosis were determined by immuno?uorescence and TUNEL staining. ATP and AMP content were assessed by ELISA. P-AMPK, ATP synthase subunits, apoptosis-related molecules and the level and activity of ROCK were determined by Western blotting. We found NR1 pretreatment ameliorated myocardial infarction, histological injury and cardiac function induced by I/R. Furthermore, similar to the effect of Y-27632, NR1 improved H9c2 cell viability, maintained actin skeleton and mitochondria morphology, and apoptosis induced by OGD/R. Importantly, NR1 prevented energy abnormity, inhibited the expression and activation of ROCK, restored the expression of ATP5D both in vivo and in vitro. Whereas, U-46619 suppressed the effect of NR1. These results prove NR1 as an agent able to prevent I/R-induced energy metabolism disorder via inhibiting ROCK and enhancing ATP5D, which at least partially contributes to its protection against cardiac I/R injury.
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Structural evolvement and thermoelectric properties of Cu3-xSnxSe3 compounds with diamond-like crystal structures.
Dalton Trans
PUBLISHED: 10-07-2014
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Polycrystalline samples of Cu3-xSnxSe3 were synthesized in the composition range x = 0.87-1.05. A compositionally induced evolvement from tetragonal via cubic to monoclinic crystal structures is observed, when the composition changes from a Cu-rich to a Sn-rich one. The Cu3-xSnxSe3 materials show a metal-to-semiconductor transition with increasing x. Electronic transport properties are governed by the charge-carrier concentration which is well described by a linear dispersion-band model. The lattice component of the thermal conductivity is practically independent of x which is attributed to the opposite influence of the atomic ordering and the inhomogeneous distribution of the Cu-Se or Sn-Se bonds with different polarities in the crystal structure. The highest thermoelectric figure of merit ZT of 0.34 is achieved for x = 1.025 at 700 K.
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Patterns of food consumption among vegetarians and non-vegetarians.
Br. J. Nutr.
PUBLISHED: 09-23-2014
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Vegetarian dietary patterns have been reported to be associated with a number of favourable health outcomes in epidemiological studies, including the Adventist Health Study 2 (AHS-2). Such dietary patterns may vary and need further characterisation regarding foods consumed. The aims of the present study were to characterise and compare the food consumption patterns of several vegetarian and non-vegetarian diets. Dietary intake was measured using an FFQ among more than 89 000 members of the AHS-2 cohort. Vegetarian dietary patterns were defined a priori, based on the absence of certain animal foods in the diet. Foods were categorised into fifty-eight minor food groups comprising seventeen major food groups. The adjusted mean consumption of each food group for the vegetarian dietary patterns was compared with that for the non-vegetarian dietary pattern. Mean consumption was found to differ significantly across the dietary patterns for all food groups. Increased consumption of many plant foods including fruits, vegetables, avocados, non-fried potatoes, whole grains, legumes, soya foods, nuts and seeds was observed among vegetarians. Conversely, reduced consumption of meats, dairy products, eggs, refined grains, added fats, sweets, snack foods and non-water beverages was observed among vegetarians. Thus, although vegetarian dietary patterns in the AHS-2 have been defined based on the absence of animal foods in the diet, they differ greatly with respect to the consumption of many other food groups. These differences in food consumption patterns may be important in helping to explain the association of vegetarian diets with several important health outcomes.
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Serine Catabolism Regulates Mitochondrial Redox Control during Hypoxia.
Cancer Discov
PUBLISHED: 09-03-2014
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The de novo synthesis of the nonessential amino acid serine is often upregulated in cancer. In this study, we demonstrate that the serine catabolic enzyme, mitochondrial serine hydroxymethyltransferase (SHMT2), is induced when MYC-transformed cells are subjected to hypoxia. In mitochondria, SHMT2 can initiate the degradation of serine to CO2 and NH4 (+), resulting in net production of NADPH from NADP(+). Knockdown of SHMT2 in MYC-dependent cells reduced cellular NADPH:NADP(+) ratio, increased cellular reactive oxygen species, and triggered hypoxia-induced cell death. In vivo, SHMT2 suppression led to impaired tumor growth. In MYC-amplified neuroblastoma patient samples, there was a significant correlation between SHMT2 and hypoxia-inducible factor-1 ? (HIF1?), and SHMT2 expression correlated with unfavorable patient prognosis. Together, these data demonstrate that mitochondrial serine catabolism supports tumor growth by maintaining mitochondrial redox balance and cell survival.
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Stability of bonds made to superficial vs. deep dentin, before and after thermocycling.
Dent Mater
PUBLISHED: 08-31-2014
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Bonding stability of resinous adhesives to dentin is still problematic and may involve regional variations in dentin composition. This study is to evaluate the effect of dentin depth on the stability of resin-dentin bonds under thermocycling challenge.
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Tibial lengthening for unilateral Crowe type-IV developmental dysplasia of the hip.
Indian J Orthop
PUBLISHED: 08-22-2014
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Developmental dysplasia of the hip (DDH) is associated with chronic pain and limping which especially has a negative impact on the patients' daily activities, body image, and self-esteem. Although total hip arthroplasty remains the first choice for treatment of DDH in adults, minimally invasive alternative approaches are being increasingly favored both by the surgeon and the patients with severe DDH. This study aimed to evaluate the outcome of these patients treated with a mono-lateral external fixator-based tibial lengthening procedure.
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Calix[4]pyrroles: highly selective stationary phases for gas chromatographic separations.
J Chromatogr A
PUBLISHED: 08-20-2014
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Calix[4]pyrroles offer a great potential as stationary phases for gas chromatography (GC) due to their unique structures and physicochemical properties. Herein we present the first report of using two calix[4]pyrroles, namely meso-tetra-cyclohexylcalix[4]pyrrole (THCP) and meso-octamethylcalix[4]pyrrole (OMCP). These stationary phases were statically coated onto capillary columns and investigated in terms of column efficiency, polarity, separation performance, thermal stability and repeatability. The columns achieved column efficiencies of 2200-3000plates/m and exhibited nonpolar nature with an average polarity of 67 for THCP and 64 for OMCP, respectively. THCP stationary phase shows high selectivity for analytes of different polarity and exhibits nice peak shapes, especially for aldehydes, alcohols and anilines that are prone to severe peak tailing in GC analysis. Interestingly, THCP stationary phase possesses superior resolving ability for aniline and benzenediol positional isomers while OMCP shows preferential selectivity for nonpolar analytes such as hexane isomers. Moreover, calix[4]pyrrole columns also have good thermal stability up to 260°C and repeatability with a relative standard deviation (RSD%) of less than 0.10% for run-to-run and less than 5.2% for column-to-column. This work demonstrates the unique separation performance of calix[4]pyrroles and their promising future as a new class of GC stationary phases.
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Polycyclic aromatic hydrocarbons in deposited bedroom dust collected from Xinxiang, a fast developing city in North China.
Environ Monit Assess
PUBLISHED: 07-24-2014
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To investigate the contamination levels of polycyclic aromatic hydrocarbons (PAHs) in the indoor environment, 16 PAHs were measured in 20 deposited bedroom dust (DBD) samples collected from four residential areas in Xinxiang City. The total PAH concentrations (?PAHs, defined as the sum of 16 PAHs) in 20 DBD samples ranged from 1.47 to 21.8 ?g/g dry weight. PAH ratios indicated that main sources of PAHs in most DBD samples were coal, grasses, and wood combustion. Correlation analysis showed that there were no significant positive correlations between ?PAH concentrations in DBD and the number of family members or duration of residence. Analysis using the t test revealed that tobacco smoke was a source of PAHs in DBD and that an unattached kitchen may be a significant influencing factor related to PAHs in DBD collected from residential areas in Xinxiang City. Our results showed that the kitchen exhaust fan or hood had no significant influence on total PAHs in DBD, and there was no significant difference in ?PAH concentrations in DBD in homes which used liquefied petroleum gas and those which used natural gas.
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[Application of three-probe fluorescence in situ hybridization panel in the diagnosis of pediatric B cell acute lymphoblastic leukemia].
Zhonghua Xue Ye Xue Za Zhi
PUBLISHED: 07-03-2014
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To evaluate the three-probe fluorescence in situ hybridization (FISH) panel in the diagnosis of pediatric B cell acute lymphoblastic leukemia (B-ALL).
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Infection of Ustilaginoidea virens intercepts rice seed formation but activates grain-filling-related genes.
J Integr Plant Biol
PUBLISHED: 06-27-2014
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Rice false smut has become an increasingly serious disease in rice production worldwide. The typical feature of this disease is that the fungal pathogen Ustilaginoidea virens (Uv) specifically infects rice flower and forms false smut balls, the ustiloxins-containing ball-like fungal colony, of which the size is usually several times larger than that of a mature rice seed. However, the underlying mechanisms of Uv-rice interaction are poorly understood. Here, we applied time-course microscopic and transcriptional approaches to investigate rice responses to Uv infection. The results demonstrated that flower-opening process and expression of associated transcription factors, including ARF6 and ARF8, were inhibited in Uv-infected spikelets. The ovaries in infected spikelets were interrupted in fertilization and thus were unable to set seeds. However, a number of grain-filling-related genes, including seed storage protein genes, starch anabolism genes and endosperm-specific transcription factors (RISBZ1 and RPBF), were highly transcribed as if the ovaries were fertilized. In addition, critical defense-related genes like NPR1 and PR1 were down-regulated by Uv infection. Our data imply that Uv might hijack host nutrient reservoir by activation of grain-filling network for the need of growth and formation of false smut balls.
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Stoichiometry of site-specific lysine acetylation in an entire proteome.
J. Biol. Chem.
PUBLISHED: 06-10-2014
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Acetylation of lysine ?-amino groups influences many cellular processes and has been mapped to thousands of sites across many organisms. Stoichiometric information of acetylation is essential to accurately interpret biological significance. Here, we developed and employed a novel method for directly quantifying stoichiometry of site-specific acetylation in the entire proteome of Escherichia coli. By coupling isotopic labeling and a novel pairing algorithm, our approach performs an in silico enrichment of acetyl peptides, circumventing the need for immunoenrichment. We investigated the function of the sole NAD(+)-dependent protein deacetylase, CobB, on both site-specific and global acetylation. We quantified 2206 peptides from 899 proteins and observed a wide distribution of acetyl stoichiometry, ranging from less than 1% up to 98%. Bioinformatic analysis revealed that metabolic enzymes, which either utilize or generate acetyl-CoA, and proteins involved in transcriptional and translational processes displayed the highest degree of acetylation. Loss of CobB led to increased global acetylation at low stoichiometry sites and induced site-specific changes at high stoichiometry sites, and biochemical analysis revealed altered acetyl-CoA metabolism. Thus, this study demonstrates that sirtuin deacetylase deficiency leads to both site-specific and global changes in protein acetylation stoichiometry, affecting central metabolism.
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Ectopic expression of RESISTANCE TO POWDERY MILDEW8.1 confers resistance to fungal and oomycete pathogens in Arabidopsis.
Plant Cell Physiol.
PUBLISHED: 06-04-2014
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Broad-spectrum disease resistance is a highly valuable trait in plant breeding and attracts special attention in research. The Arabidopsis gene locus RESISTANCE TO POWDERY MILDEW 8 (RPW8) contains two adjacent homologous genes, RPW8.1 and RPW8.2, and confers broad-spectrum resistance to powdery mildew. Remarkably, the RPW8.2 protein is specifically localized to the extrahaustorial membrane (EHM) encasing the feeding structure of powdery mildew whereby RPW8.2 activates haustorium-targeted defenses. Here, we show that ectopic expression of the yellow fluorescent protein (YFP)-tagged RPW8.1 from the native promoter leads to unique cell death lesions and enhances resistance to virulent fungal and oomycete pathogens that cause powdery mildew and downy mildew diseases, respectively. In powdery mildew-infected plants, RPW8.1-YFP accumulates at higher levels in the mesophyll cells underneath the infected epidermal cells where RPW8.2-YFP is mainly expressed. This cell type-preferential protein accumulation pattern largely correlates with that of H(2)O(2) accumulation, suggesting that RPW8.1 may spatially collaborate with RPW8.2 in activation of resistance to powdery mildew. Interestingly, when ectopically expressed from the RPW8.2 promoter, RPW8.1-YFP is also targeted to the EHM of powdery mildew and the transgenic plants display resistance to both powdery mildew and downy mildew. Using YFP as a reporter, we further reveal that the RPW8.1 promoter is constitutively active but induced to higher levels in cells at the infection site, whereas the RPW8.2 promoter is activated specifically in cells at the infection site. Taken together, our results suggest that RPW8.1 (and its promoter) is functionally distinct from RPW8.2 and may have a higher potential in engineering broad-spectrum resistance in plants.
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Endostar, a novel human recombinant endostatin, attenuates liver fibrosis in CCl4-induced mice.
Exp. Biol. Med. (Maywood)
PUBLISHED: 05-28-2014
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Decreasing hepatic fibrosis remains one of the major therapeutic challenges in hepatology. The present study aims to evaluate the effect of Endostar on both CCl4-induced liver fibrosis in mice and a hepatic stellate cell (HSC) line. Two main models were studied: (i) a liver fibrosis model was induced in BALB/c mice using CCl4 by intraperitoneal injection for six weeks. Six animal groups were studied: group 1: normal animals; group 2: CCl4-induced liver fibrosis; group 3: CCl4?+?Endostar 20?mg/kg/d, six weeks; group 4: CCl4?+?Endostar 10?mg/kg/d, six weeks; group 5: CCl4?+?Endostar 20?mg/kg/d, four weeks; group 6: CCl4?+?Endostar 10?mg/kg/d, four weeks corresponded to different Endostar doses and duration of administration. Liver fibrosis was evaluated by histopathological staining and liver hydroxyproline content. Expressions of collagen type I, ?-smooth muscle actin (?-SMA), TGF-?1 and VEGFR were measured by real-time polymerase chain reaction (PCR). (ii) A liver cell model. HSC-T6 cells were cultured with or without Endostar for 12?h or 24?h. Expressions of collagen type I, ?-SMA, and TGF-?1 were measured by real-time PCR. Collagen I and transforming growth factor ?1 (TGF-?1) contents in cell supernatant were measured by enzyme-linked immunosorbent assay. As compared to the group without Endostar, liver fibrosis scores and hydroxyproline content were decreased in both Endostar groups (P?
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The binding affinity of phthalate plasticizers-protein revealed by spectroscopic techniques and molecular modeling.
Food Chem. Toxicol.
PUBLISHED: 05-26-2014
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Phthalate plasticizers have been subjected to close scrutiny and evidences of their toxicity and other negative environmental impacts have arisen as a result of their use in food in some countries. Once entering human body, plasticizers could affect the conformation of human serum albumin and protein function. The interaction between two phthalate plasticizers and human serum albumin was investigated by multispectroscopic techniques and molecular modeling. The alteration in protein conformational stability was determined by fluorescence quenching data. The thermodynamic parameters indicated that the hydrophobic interactions played a major role in the process. In addition, the alterations of HSA secondary structure in the presence of phthalate plasticizers were investigated. Molecular modeling and displacement experiments showed that phthalate plasticizers situated within subdomain IIA (site I) of HSA. Furthermore, the binding distances for the plasticizers-HSA system were provided by the efficiency of fluorescence resonance energy transfer.
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[Analysis of retinopathy of prematurity with birth weight higher than 2 kg in Xi'an area].
Zhonghua Yan Ke Za Zhi
PUBLISHED: 05-21-2014
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To survey popularity and clinical characteristics of retinopathy of prematurity (ROP) in Xi'an area in infants with birth weight over 2 000 g.
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Oregonin from the Bark of Alnus japonica Restrained Ischemia-Reperfusion-Induced Mesentery Oxidative Stress by Inhibiting NADPH Oxidase Activation.
Microcirculation
PUBLISHED: 05-09-2014
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NADPH oxidase activation results in ROS overproduction that is the pathological basis of I/R injury. This study aimed to investigate potential effects of ORG on I/R-induced ROS production in rat mesenteric microvasculature and underlying mechanisms.
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Associations of Rhesus and non-Rhesus maternal red blood cell alloimmunization with stillbirth and preterm birth.
Int J Epidemiol
PUBLISHED: 05-05-2014
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Although the risks of adverse pregnancy outcomes associated with anti-D antibodies are well-recognized, much less is known concerning alloimmunization with other red blood cell antibodies detected during routine maternal screening. To date, most reports of adverse pregnancy outcomes associated with non-anti-D antibodies have been from small case studies. The aim of this study was to examine the associations of maternal alloimmunization with specific red blood cell antibodies and the risks of preterm birth and stillbirth in the Swedish population.
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A Sub-Element in PRE enhances nuclear export of intronless mRNAs by recruiting the TREX complex via ZC3H18.
Nucleic Acids Res.
PUBLISHED: 04-29-2014
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Viral RNA elements that facilitate mRNA export are useful tools for identifying cellular RNA export factors. Here we show that hepatitis B virus post-transcriptional element (PRE) is one such element, and using PRE several new cellular mRNA export factors were identified. We found that PRE drastically enhances the cytoplasmic accumulation of cDNA transcripts independent of any viral protein. Systematic deletion analysis revealed the existence of a 116 nt functional Sub-Element of PRE (SEP1). The RNP that forms on the SEP1 RNA was affinity purified, in which TREX components as well as several other proteins were identified. TREX components and the SEP1-associating protein ZC3H18 are required for SEP1-mediated mRNA export. Significantly, ZC3H18 directly binds to the SEP1 RNA, interacts with TREX and is required for stable association of TREX with the SEP1-containing mRNA. Requirements for SEP1-mediated mRNA export are similar to those for splicing-dependent mRNA export. Consistent with these similarities, several SEP1-interacting proteins, including ZC3H18, ARS2, Acinus and Brr2, are required for efficient nuclear export of polyA RNAs. Together, our data indicate that SEP1 enhances mRNA export by recruiting TREX via ZC3H18. The new mRNA export factors that we identified might be involved in cap- and splicing-dependent TREX recruitment to cellular mRNAs.
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Magnetic beads-based chemiluminescent assay for ultrasensitive detection of pseudorabies virus.
J Nanosci Nanotechnol
PUBLISHED: 04-17-2014
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A rapid, ultrasensitive and economical Pseudorabies virus (PRV) detection system based on magnetic beads (MBs) and chemiluminescence was developed in this paper. The carboxyl functionalized MBs (MBs-COOH) were covalently coupled with aminated DNA probes for capturing PRV biotinylated amplicon, the product of polymerase chain reaction (PCR). Agarose gel electrophoresis analysis approved the reliability of biotinylated amplicon. The MBs composites were incubated with alkaline phosphatase labeled streptavidin (ALP-SA) and chemiluminescene was determined by subsequently adding 3-(2'-spiroadamantane)-4-methoxy-4-(3"-phosphoryloxy)phenyl-1,2-dioxetane (AMPPD). The optimal conditions of the PRV detection method were 10 microM for probe concentration, 50 degrees C for hybridization temperature and 30 min for hybridization time. The limit of detection (LOD) was as low as 100 amol/5 pM of amplicon which proved that this approach for PRV detection was ultrasensitive.
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Applications of nanotechnology in gastric cancer: detection and prevention by nutrition.
J Nanosci Nanotechnol
PUBLISHED: 04-16-2014
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New and emerging technologies, such as nanotechnology, have the potential to advance nutrition science by assisting in the discovery, development, and delivery of several intervention strategies to improve health and reduce the risk and complications of several diseases, including gastric cancer. This article reviews gastric cancer in relation to nutrition, discussing gastric carcinogenesis in-depth in relation to prevention of the disease by nutrition, as well as current detection approaches using nanotechnology. The current status of molecular nutritional biomarkers for gastric cancer is also discussed, as well as future strategies for the tailored management of gastric cancer.
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Inhibitory effect of rhynchophylline on contraction of cerebral arterioles to endothelin 1: role of rho kinase.
J Ethnopharmacol
PUBLISHED: 04-13-2014
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Rhynchophylline (Rhy) is a major ingredient of Uncaria rhynchophylla (UR) used to reduce blood pressure and ameliorate brain ailments. This study was to examine the role of Rho kinase (ROCK) in the inhibition of Rhy on contraction of cerebral arterioles caused by endothelin 1 (ET-1).
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17?-Estradiol inhibits ER stress-induced apoptosis through promotion of TFII-I-dependent Grp78 induction in osteoblasts.
Lab. Invest.
PUBLISHED: 03-20-2014
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Although many studies have suggested that estrogen prevents postmenopausal bone loss partially due to its anti-apoptosis effects in osteoblasts, the underlying mechanism has not been fully elucidated. In the present study, we found that 17?-estradiol (17?-E?), one of the primary estrogens, inhibited endoplasmic reticulum (ER) stress-induced apoptosis in MC3T3-E1 cells and primary osteoblasts. Interestingly, 17?-E?-promoted Grp78 induction, but not CHOP induction in response to ER stress. We further confirmed that Grp78-specific siRNA reversed the inhibition of 17?-E? on ER stress-induced apoptosis by activating caspase-12 and caspase-3. Moreover, we found that 17?-E? markedly increased the phosphorylated TFII-I levels and nuclear localization of TFII-I in ER stress conditions. 17?-E? stimulated Grp78 promoter activity in a dose-dependent manner in the presence of TFII-I and enhanced the binding of TFII-I to the Grp78 promoter. In addition, 17?-E? notably increased phosphorylated ERK1/2 levels and Ras kinase activity in MC3T3-E1 cells. The ERK1/2 activity-specific inhibitor U0126 remarkably blocked 17?-E?-induced TFII-I phosphorylation and Grp78 expression in response to ER stress. Together, 17?-E? protected MC3T3-E1 cells against ER stress-induced apoptosis by promoting Ras-ERK1/2-TFII-I signaling pathway-dependent Grp78 induction.
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Vegetarian diets and cardiovascular risk factors in black members of the Adventist Health Study-2.
Public Health Nutr
PUBLISHED: 03-19-2014
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To compare cardiovascular risk factors between vegetarians and non-vegetarians in black individuals living in the USA.
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Icariside II improves cerebral microcirculatory disturbance and alleviates hippocampal injury in gerbils after ischemia-reperfusion.
Brain Res.
PUBLISHED: 03-18-2014
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the purpose of the present study was to examine the protective effect of Icariside II (IS) on cerebral microcirculatory disturbance and neuronal injury in hippocampal CA1 region induced by global cerebral I/R and the underlying mechanism.
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Posttreatment with ma-xing-shi-gan-tang, a chinese medicine formula, ameliorates lipopolysaccharide-induced lung microvessel hyperpermeability and inflammatory reaction in rat.
Microcirculation
PUBLISHED: 03-11-2014
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The aim of present study was to investigate the efficacy of MXSGT, a traditional Chinese medicine formula used for treatment of respiratory system diseases, in the LPS-induced rat ALI particularly with a focus on its effect on lung microvascular hyperpermeability and inflammatory reaction.
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Quantitative flux analysis reveals folate-dependent NADPH production.
Nature
PUBLISHED: 03-06-2014
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ATP is the dominant energy source in animals for mechanical and electrical work (for example, muscle contraction or neuronal firing). For chemical work, there is an equally important role for NADPH, which powers redox defence and reductive biosynthesis. The most direct route to produce NADPH from glucose is the oxidative pentose phosphate pathway, with malic enzyme sometimes also important. Although the relative contribution of glycolysis and oxidative phosphorylation to ATP production has been extensively analysed, similar analysis of NADPH metabolism has been lacking. Here we demonstrate the ability to directly track, by liquid chromatography-mass spectrometry, the passage of deuterium from labelled substrates into NADPH, and combine this approach with carbon labelling and mathematical modelling to measure NADPH fluxes. In proliferating cells, the largest contributor to cytosolic NADPH is the oxidative pentose phosphate pathway. Surprisingly, a nearly comparable contribution comes from serine-driven one-carbon metabolism, in which oxidation of methylene tetrahydrofolate to 10-formyl-tetrahydrofolate is coupled to reduction of NADP(+) to NADPH. Moreover, tracing of mitochondrial one-carbon metabolism revealed complete oxidation of 10-formyl-tetrahydrofolate to make NADPH. As folate metabolism has not previously been considered an NADPH producer, confirmation of its functional significance was undertaken through knockdown of methylenetetrahydrofolate dehydrogenase (MTHFD) genes. Depletion of either the cytosolic or mitochondrial MTHFD isozyme resulted in decreased cellular NADPH/NADP(+) and reduced/oxidized glutathione ratios (GSH/GSSG) and increased cell sensitivity to oxidative stress. Thus, although the importance of folate metabolism for proliferating cells has been long recognized and attributed to its function of producing one-carbon units for nucleic acid synthesis, another crucial function of this pathway is generating reducing power.
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Estrogen improves the proliferation and differentiation of hBMSCs derived from postmenopausal osteoporosis through notch signaling pathway.
Mol. Cell. Biochem.
PUBLISHED: 03-05-2014
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Estrogen deficiency is the main reason of bone loss, leading to postmenopausal osteoporosis, and estrogen replacement therapy (ERT) has been demonstrated to protect bone loss efficiently. Notch signaling controls proliferation and differentiation of bone marrow-derived mesenchymal stem cells (BMSCs). Moreover, imperfect estrogen-responsive elements (EREs) were found in the 5'-untranslated region of Notch1 and Jagged1. Thus, we examined the molecular and biological links between estrogen and the Notch signaling in postmenopausal osteoporosis in vitro. hBMSCs were obtained from healthy women and patients with postmenopausal osteoporosis. Notch signaling molecules were quantified using real-time polymerase chain reaction (real-time PCR) and Western Blot. Luciferase reporter constructs with putative EREs were transfected into hBMSCs and analyzed. hBMSCs were transduced with lentiviral vectors containing human Notch1 intracellular domain (NICD1). We also used N-[N-(3, 5-diflurophenylacetate)-l-alanyl]-(S)-phenylglycine t-butyl ester, a ?-secretase inhibitor, to suppress the Notch signaling. We found that estrogen enhanced the Notch signaling in hBMSCs by promoting the expression of Jagged1. hBMSCs cultured with estrogen resulted in the up-regulation of Notch signaling and increased proliferation and differentiation. Enhanced Notch signaling could enhance the proliferation and differentiation of hBMSCs from patients with postmenopausal osteoporosis (OP-hBMSCs). Our results demonstrated that estrogen preserved bone mass partly by activating the Notch signaling. Because long-term ERT has been associated with several side effects, the Notch signaling could be a potential target for treating postmenopausal osteoporosis.
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Role of NADPH Oxidase in Total Salvianolic Acid Injection Attenuating Ischemia-Reperfusion Impaired Cerebral Microcirculation and Neurons: Implication of AMPK/Akt/PKC.
Microcirculation
PUBLISHED: 03-03-2014
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TSI is a new drug derived from Chinese medicine for treatment of ischemic stroke in China. The aim of this study was to verify the therapeutic effect of TSI in a rat model of MCAO, and further explore the mechanism for its effect.
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Ginsenoside-Rb2 displays anti-osteoporosis effects through reducing oxidative damage and bone-resorbing cytokines during osteogenesis.
Bone
PUBLISHED: 02-27-2014
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Reactive oxygen species (ROS) are a significant pathogenic factor of osteoporosis. Ginsenoside-Rb2 (Rb2), a 20(S)-protopanaxadiol glycoside extracted from ginseng, is a potent antioxidant that generates interest regarding the bone metabolism area. We tested the potential anti-osteoporosis effects of Rb2 and its underlying mechanism in this study. We produced an oxidative damage model induced by hydrogen peroxide (H2O2) in osteoblastic MC3T3-E1 cells to test the essential anti-osteoporosis effects of Rb2in vitro. The results indicated that treatment of 0.1 to 10?M Rb2 promoted the proliferation of MC3T3-E1 cells, improved alkaline phosphatase (ALP) expression, elevated calcium mineralization and mRNA expressions of Alp, Col1a1, osteocalcin (Ocn) and osteopontin (Opn) against oxidative damage induced by H2O2. Importantly, Rb2 reduced the expression levels of receptor activator of nuclear factor kappa-B ligand (RANKL) and IL-6 and inhibited the H2O2-induced production of ROS. The in vivo study indicated that the Rb2 administered for 12weeks partially decreased blood malondialdehyde (MDA) activity and elevated the activity of reduced glutathione (GSH) in ovariectomized (OVX) mice. Moreover, Rb2 improved the micro-architecture of trabecular bones and increased bone mineral density (BMD) of the 4th lumbar vertebrae (L4) and the distal femur. Altogether, these results demonstrated that the potential anti-osteoporosis effects of Rb2 were linked to a reduction of oxidative damage and bone-resorbing cytokines, which suggests that Rb2 might be effective in preventing and alleviating osteoporosis.
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Identification of genomic alterations in oesophageal squamous cell cancer.
Nature
PUBLISHED: 02-25-2014
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Oesophageal cancer is one of the most aggressive cancers and is the sixth leading cause of cancer death worldwide. Approximately 70% of global oesophageal cancer cases occur in China, with oesophageal squamous cell carcinoma (ESCC) being the histopathological form in the vast majority of cases (>90%). Currently, there are limited clinical approaches for the early diagnosis and treatment of ESCC, resulting in a 10% five-year survival rate for patients. However, the full repertoire of genomic events leading to the pathogenesis of ESCC remains unclear. Here we describe a comprehensive genomic analysis of 158 ESCC cases, as part of the International Cancer Genome Consortium research project. We conducted whole-genome sequencing in 17 ESCC cases and whole-exome sequencing in 71 cases, of which 53 cases, plus an additional 70 ESCC cases not used in the whole-genome and whole-exome sequencing, were subjected to array comparative genomic hybridization analysis. We identified eight significantly mutated genes, of which six are well known tumour-associated genes (TP53, RB1, CDKN2A, PIK3CA, NOTCH1, NFE2L2), and two have not previously been described in ESCC (ADAM29 and FAM135B). Notably, FAM135B is identified as a novel cancer-implicated gene as assayed for its ability to promote malignancy of ESCC cells. Additionally, MIR548K, a microRNA encoded in the amplified 11q13.3-13.4 region, is characterized as a novel oncogene, and functional assays demonstrate that MIR548K enhances malignant phenotypes of ESCC cells. Moreover, we have found that several important histone regulator genes (MLL2 (also called KMT2D), ASH1L, MLL3 (KMT2C), SETD1B, CREBBP and EP300) are frequently altered in ESCC. Pathway assessment reveals that somatic aberrations are mainly involved in the Wnt, cell cycle and Notch pathways. Genomic analyses suggest that ESCC and head and neck squamous cell carcinoma share some common pathogenic mechanisms, and ESCC development is associated with alcohol drinking. This study has explored novel biological markers and tumorigenic pathways that would greatly improve therapeutic strategies for ESCC.
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Tropomyosin-related kinase B promotes distant metastasis of colorectal cancer through protein kinase B-mediated anoikis suppression and correlates with poor prognosis.
Apoptosis
PUBLISHED: 02-20-2014
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An increasing amount of evidence demonstrated that the neurotrophic receptor tropomyosin-related kinase B (TrkB) plays a critical role in the development and progression of multiple types of cancer. However, its underlying mechanism in distant metastasis through the circulatory and lymphatic systems in colorectal cancer (CRC) is still unclear. Here we showed that downregulation of TrkB using short hairpin RNA obviously increased anoikis (detachment-induced apoptosis resulting from loss of cell-matrix interactions) sensitivity of CRC cells in vitro. Furthermore, using tail vein injection model, we confirmed that silencing TrkB significantly inhibited metastasis of CRC cells in vivo. Conversely, overexpression of TrkB obviously protected CRC cells from anoikis in vitro. Both loss- and gain-of-functional experiments indicated that TrkB could be a functional molecule in anti-anoikis of CRC cells. Mechanistically, we found that protein kinase B (PKB, also known as Akt) signaling pathway was a functional link in TrkB-induced anoikis suppression in CRC cells. Phosphorylation levels of Akt are closely related with the expression pattern of TrkB in CRC cells and inhibition of Akt activation robustly induces anoikis of CRC cells in vitro. In addition, our clinical investigation showed that high TrkB expression levels in CRC patients were associated with lymph node metastasis, distant metastasis and unfavourable prognosis. Thus, based on our results, this study suggests that an important function of TrkB is to protect CRC cells from anoikis in the circulatory and lymphatic systems, and that TrkB could be a promising candidate in CRC therapy, especially in the inhibition of cancer metastasis.
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MicroRNA?125b suppresses the proliferation and osteogenic differentiation of human bone marrow?derived mesenchymal stem cells.
Mol Med Rep
PUBLISHED: 02-19-2014
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The regressive biological function of human bone marrow?derived mesenchymal stem cells (hBMSCs) is one of the key factors resulting in the decrease of bone mass in senile osteoporosis. MicroRNAs (miRs) are non?coding small RNAs involved in various gene regulation processes. Whether any miR(s) are involved in the progression of osteoporosis by regulating the biological function of hBMSCs remains to be elucidated. The present study aimed to compare the expression levels of miR?125b in hBMSCs derived from senile osteoporotic patients with that of control (normal) subjects. A significantly upregulated expression of miR?125b in osteoporotic hBMSCs was detected. To elucidate the biological function of miR?125b in senile osteoporosis, the effects of miR?125b expression on proliferation and osteogenic differentiation of hBMSCs were assessed using gain? and loss?of?function studies. It was evident that the overexpression of a miR?125b mimic was able to suppress the proliferative and osteogenic differentiation of senile hBMSCs. In contrast, repression of the function of miR?125b by transfection of an miR?125b inhibitor promoted the proliferation and osteogenic differentiation of hBMSCs. Furthermore, the potential target gene of miR?125b, osterix (Osx), was examined. The results of the present study strongly suggested that miR?125b may regulate osteogenic differentiation of hBMSCs through the modulation of Osx expression.
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Asparagine plays a critical role in regulating cellular adaptation to glutamine depletion.
Mol. Cell
PUBLISHED: 02-14-2014
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Many cancer cells consume large quantities of glutamine to maintain TCA cycle anaplerosis and support cell survival. It was therefore surprising when RNAi screening revealed that suppression of citrate synthase (CS), the first TCA cycle enzyme, prevented glutamine-withdrawal-induced apoptosis. CS suppression reduced TCA cycle activity and diverted oxaloacetate, the substrate of CS, into production of the nonessential amino acids aspartate and asparagine. We found that asparagine was necessary and sufficient to suppress glutamine-withdrawal-induced apoptosis without restoring the levels of other nonessential amino acids or TCA cycle intermediates. In complete medium, tumor cells exhibiting high rates of glutamine consumption underwent rapid apoptosis when glutamine-dependent asparagine synthesis was suppressed, and expression of asparagine synthetase was statistically correlated with poor prognosis in human tumors. Coupled with the success of L-asparaginase as a therapy for childhood leukemia, the data suggest that intracellular asparagine is a critical suppressor of apoptosis in many human tumors.
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Alterations in STriatal-Enriched protein tyrosine Phosphatase expression, activation, and downstream signaling in early and late stages of the YAC128 Huntington's disease mouse model.
J. Neurochem.
PUBLISHED: 02-14-2014
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Striatal neurodegeneration and synaptic dysfunction in Huntington's disease are mediated by the mutant huntingtin (mHtt) protein. MHtt disrupts calcium homeostasis and facilitates excitotoxicity, in part by altering NMDA receptor (NMDAR) trafficking and function. Pre-symptomatic (excitotoxin-sensitive) transgenic mice expressing full-length human mHtt with 128 polyglutamine repeats (YAC128 Huntington's disease mice) show increased calpain activity and extrasynaptic NMDAR (Ex-NMDAR) localization and signaling. Furthermore, Ex-NMDAR stimulation facilitates excitotoxicity in wild-type cortical neurons via calpain-mediated cleavage of STriatal-Enriched protein tyrosine Phosphatase 61 (STEP61). The cleavage product, STEP33, cannot dephosphorylate p38 mitogen-activated protein kinase (MAPK), thereby augmenting apoptotic signaling. Here, we show elevated extrasynaptic calpain-mediated cleavage of STEP61 and p38 phosphorylation, as well as STEP61 inactivation and reduced extracellular signal-regulated protein kinase 1/2 phosphorylation (ERK1/2) in the striatum of 6-week-old, excitotoxin-sensitive YAC128 mice. Calpain inhibition reduced basal and NMDA-induced STEP61 cleavage. However, basal p38 phosphorylation was normalized by a peptide disrupting NMDAR-post-synaptic density protein-95 (PSD-95) binding but not by calpain inhibition. In 1-year-old excitotoxin-resistant YAC128 mice, STEP33 levels were not elevated, but STEP61 inactivation and p38 and ERK 1/2 phosphorylation levels were increased. These results show that in YAC128 striatal tissue, enhanced NMDAR-PSD-95 interactions contributes to elevated p38 signaling in early, excitotoxin-sensitive stages, and suggest that STEP61 inactivation enhances MAPK signaling at late, excitotoxin-resistant stages. The YAC128 Huntington's disease mouse model shows early, enhanced susceptibility to NMDA receptor-mediated striatal apoptosis, progressing to late-stage excitotoxicity resistance. This study shows that elevated NMDA receptor-PSD-95 interactions as well as decreased extrasynaptic STriatal-Enriched protein tyrosine Phosphatase 61 (STEP61) activation may contribute to early enhanced apoptotic signaling. In late-stage YAC128 mice, reduced STEP61 levels and activity correlate with elevated MAPK signaling, consistent with excitotoxicity resistance. Solid and dotted arrows indicate conclusions drawn from the current study and other literature, respectively.
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Relationship between tumor and peripheral blood NPRL2 mRNA levels in patients with colorectal adenoma and colorectal cancer.
Cancer Biol. Ther.
PUBLISHED: 02-12-2014
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NPRL2 is a tumor suppressor gene involved in the progression of human cancer. The present study investigated whether NPRL2 expression correlates with colorectal cancer (CRC) progression. Colorectal tissue and peripheral blood samples were obtained from 62 patients with CRC, 38 patients with colorectal adenomas and 51 normal controls. NPRL2 mRNA levels in tissue samples and blood were measured using quantitative real-time PCR. NPRL2 protein expression was determined by immunohistochemistry. NPRL2 protein expression in CRCs was significantly lower than in the adenomas or normal colorectal tissue. NPRL2 mRNA expression was significantly decreased in adenomas compared with normal controls (P<0.0001) and it was further decreased in colorectal tumors compared with adenomas (P<0.0001). NPRL2 mRNA levels expression correlated with tumor stage. In addition, NPRL2 mRNA levels in the blood correlated with the levels detected in tumors. Furthermore, receiver operating characteristic (ROC) analysis showed that NPRL2 expression in blood could distinguish colorectal adenomas and CRCs from normal controls. NPRL2 mRNA expression in CRC tumor tissues and peripheral blood correlated with colorectal tumor progression. Based on our findings, we can conclude that NPRL2 mRNA blood levels could be a potentially useful marker for the detection of early stage adenomas and CRCs.
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Origin, timing, and gene expression profile of adventitious rooting in Arabidopsis hypocotyls and stems.
Am. J. Bot.
PUBLISHED: 02-05-2014
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Adventitious root (AR) formation is indispensable for vegetative propagation, but difficult to achieve in many crops. Understanding its molecular mechanisms is thus important for such species. Here we aimed at developing a rooting protocol for direct AR formation in stems, locating cellular AR origins in stems and exploring molecular differences underlying adventitious rooting in hypocotyls and stems.
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Protection of cultured human hepatocytes from hydrogen peroxide?induced apoptosis by relaxin?3.
Mol Med Rep
PUBLISHED: 01-28-2014
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Previous studies have suggested that hepatocyte apoptosis may be a fundamental underlying mechanism of liver injury and diseases, such as liver fibrosis. Relaxin?3 has been reported to have anti?fibrotic actions in the heart and to attenuate isoproterenol?induced myocardial injury; however, the beneficial role of relaxin?3 on hepatocyte apoptosis remains to be elucidated. The aim of the present study was to explore the role and possible mechanisms of relaxin?3 through hydrogen peroxide (H2O2)?induced apoptosis in primary human hepatocytes. Cells were treated with relaxin?3 and then cell viability, morphological features, the presence of cleaved caspases as well as the levels of endoplasmic reticulum stress (ERS) protein markers and autophagy markers were evaluated. The H2O2 group showed significantly decreased cell viability, increased apoptosis as well as upregulation of caspases (cleaved caspase?3, ?8 and ?9) and ERS protein markers compared with those of the control group. However, cells treated with relaxin?3 (10 ng/ml) demonstrated improved cell viability, reduced apoptosis and decreased expression of cleaved caspases and ERS markers. However, the expression of autophagy markers remained unchanged following H2O2?induced apoptosis and relaxin?3 treatment. In conclusion, relaxin?3 was shown to protect hepatocytes from H2O2?induced apoptosis via downregulation of cleaved caspase?8 and ?9, as well as inhibition of the ERS pathway.
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Quantitation of cellular metabolic fluxes of methionine.
Anal. Chem.
PUBLISHED: 01-16-2014
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Methionine is an essential proteogenic amino acid. In addition, it is a methyl donor for DNA and protein methylation and a propylamine donor for polyamine biosynthesis. Both the methyl and propylamine donation pathways involve metabolic cycles, and methods are needed to quantitate these cycles. Here, we describe an analytical approach for quantifying methionine metabolic fluxes that accounts for the mixing of intracellular and extracellular methionine pools. We observe that such mixing prevents isotope tracing experiments from reaching the steady state due to the large size of the media pools and hence precludes the use of standard stationary metabolic flux analysis. Our approach is based on feeding cells with (13)C methionine and measuring the isotope-labeling kinetics of both intracellular and extracellular methionine by liquid chromatography-mass spectrometry (LC-MS). We apply this method to quantify methionine metabolism in a human fibrosarcoma cell line and study how methionine salvage pathway enzyme methylthioadenosine phosphorylase (MTAP), frequently deleted in cancer, affects methionine metabolism. We find that both transmethylation and propylamine transfer fluxes amount to roughly 15% of the net methionine uptake, with no major changes due to MTAP deletion. Our method further enables the quantification of flux through the pro-tumorigenic enzyme ornithine decarboxylase, and this flux increases 2-fold following MTAP deletion. The analytical approach used to quantify methionine metabolic fluxes is applicable for other metabolic systems affected by mixing of intracellular and extracellular metabolite pools.
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Experimental and theoretical investigation on the interaction between cyclovirobuxine D and human serum albumin.
Spectrochim Acta A Mol Biomol Spectrosc
PUBLISHED: 01-13-2014
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Cyclovirobuxine D is an active compound extracted from the plant Buxux microphylla, and widely available as medications; however, its abuse may casts potential detrimental effects on human health. By using multispectroscopic techniques and molecular modeling, the interaction of cyclovirobuxine D with human serum albumin was investigated. The fluorescence results manifested that static type was the operative mechanism for the interaction with human serum albumin. The structural investigation of the complexed HSA through CD, three-dimensional, FT-IR and synchronous fluorescence shown the polypeptide chain of HSA partially destabilizing. Docking studies revealed the molecule to be bound in the subdomain IIA. Finally, we investigated the distance between the bound ligand and Trp-214 of human serum albumin.
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Binding of helicid to human serum albumin: a hybrid spectroscopic approach and conformational study.
Spectrochim Acta A Mol Biomol Spectrosc
PUBLISHED: 01-08-2014
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The interaction between human serum albumin and helicid was studied by steady-state fluorescence, ultraviolet-visible, circular dichroism, Fourier transform infrared techniques and molecular modeling. The binding site numbers, association constants, and corresponding thermodynamic parameters were used to investigate the quenching mechanism. The alternations of protein secondary structure in the presence of helicid were demonstrated using synchronous fluorescence, Fourier transform infrared, circular dichroism and three-dimensional fluorescence spectra. The molecular modeling results revealed that helicid could bind to hydrophobic pocket of HSA with hydrophobic and hydrogen bond force. The binding site of helicid in HSA was ascertained. Moreover, an apparent distance of 3.33 nm between the Trp214 and helicid was obtained via fluorescence resonance energy transfer method.
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25th anniversary article: double emulsion templated solid microcapsules: mechanics and controlled release.
Adv. Mater. Weinheim
PUBLISHED: 01-02-2014
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How droplet microfluidics can be used to fabricate solid-shelled microcapsules having precisely controlled release behavior is described. Glass capillary devices enable the production of monodisperse double emulsion drops, which can then be used as templates for microcapsule formation. The exquisite control afforded by microfluidics can be used to tune the compositions and geometrical characteristics of the microcapsules with exceptional precision. The use of this approach to fabricate microcapsules that only release their contents when exposed to a specific stimulus--such as a change in temperature, exposure to light, a change in the chemical environment, or an external stress--only after a prescribed time delay, and at a prescribed rate is reviewed.
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Dose-dependent effect of estrogen suppresses the osteo-adipogenic transdifferentiation of osteoblasts via canonical Wnt signaling pathway.
PLoS ONE
PUBLISHED: 01-01-2014
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Fat infiltration within marrow cavity is one of multitudinous features of estrogen deficiency, which leads to a decline in bone formation functionality. The origin of this fat is unclear, but one possibility is that it is derived from osteoblasts, which transdifferentiate into adipocytes that produce bone marrow fat. We examined the dose-dependent effect of 17?-estradiol on the ability of MC3T3-E1 cells and murine bone marrow-derived mesenchymal stem cell (BMMSC)-derived osteoblasts to undergo osteo-adipogenic transdifferentiation. We found that 17?-estradiol significantly increased alkaline phosphatase activity (P<0.05); calcium deposition; and Alp, Col1a1, Runx2, and Ocn expression levels dose-dependently. By contrast, 17?-estradiol significantly decreased the number and size of lipid droplets, and Fabp4 and PPAR? expression levels during osteo-adipogenic transdifferentiation (P<0.05). Moreover, the expression levels of brown adipocyte markers (Myf5, Elovl3, and Cidea) and undifferentiated adipocyte markers (Dlk1, Gata2, and Wnt10b) were also affected by 17?-estradiol during osteo-adipogenic transdifferentiation. Western blotting and immunostaining further showed that canonical Wnt signaling can be activated by estrogen to exert its inhibitory effect of osteo-adipogenesis. This is the first study to demonstrate the dose-dependent effect of 17?-estradiol on the osteo-adipogenic transdifferentiation of MC3T3-E1 cells and BMMSCs likely via canonical Wnt signaling. In summary, our results indicate that osteo-adipogenic transdifferentiation modulated by canonical Wnt signaling pathway in bone metabolism may be a new explanation for the gradually increased bone marrow fat in estrogen-inefficient condition.
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Soy isoflavone intake and the likelihood of ever becoming a mother: the Adventist Health Study-2.
Int J Womens Health
PUBLISHED: 01-01-2014
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As little is known about the possible relationship between the intake of phytoestrogens and female fertility, we investigated the relationship between soy isoflavone intake and the risk of nulliparity and nulligravidity.
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A microRNA signature predicts survival in early stage small-cell lung cancer treated with surgery and adjuvant chemotherapy.
PLoS ONE
PUBLISHED: 01-01-2014
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Small-cell lung cancer (SCLC) is one of the most aggressive cancers, yet the molecular mechanisms underlying its devastating clinical outcome remain elusive. In this study, we investigated whether microRNA (miRNA) expression profiles can predict the clinical outcomes of SCLC patients. A total of 82 patients with limited SCLC, who were treated with surgical resection and adjuvant chemotherapy, were enrolled in this study. First, we surveyed the expression of 924 miRNAs from 42 SCLC patients to discover survival-relevant miRNAs and develop prognostic models, which were then validated in an independent cohort of 40 cases using quantitative real-time PCR. We found that the miR-150/miR-886-3p signature was significantly correlated with the overall survival (OS) of SCLC patients (p?=?0.02) in the training set, and both miRNA expression levels were much lower in the SCLC samples than normal lung samples. The miRNA signature also proved to be a significant predictor of survival in the validation set. Patients with high-risk miRNA signatures had poor overall survival (p?=?0.005) and progression-free survival (p?=?0.017) compared with those with low-risk scores. These findings retained statistical significance after adjusting for age, gender and smoking status (HR: 0.26, 95%: CI 0.10-0.69, p?=?0.007), which suggested it may be an independent predictor of survival. In summary, we developed a prognostic miR-150/miR-886-3p signature and validated expression in an independent dataset of resectable SCLC. These preliminary results indicated that miRNAs may serve as promising molecular prognostic markers and new therapeutic targets for SCLC.
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Detection and analysis of human papillomavirus (HPV) DNA in breast cancer patients by an effective method of HPV capture.
PLoS ONE
PUBLISHED: 01-01-2014
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Despite an increase in the number of molecular epidemiological studies conducted in recent years to evaluate the association between human papillomavirus (HPV) and the risk of breast carcinoma, these studies remain inconclusive. Here we aim to detect HPV DNA in various tissues from patients with breast carcinoma using the method of HPV capture combined with massive paralleled sequencing (MPS). To validate the confidence of our methods, 15 cervical cancer samples were tested by PCR and the new method. Results showed that there was 100% consistence between the two methods.DNA from peripheral blood, tumor tissue, adjacent lymph nodes and adjacent normal tissue were collected from seven malignant breast cancer patients, and HPV type 16 (HPV16) was detected in 1/7, 1/7, 1/7 and 1/7 of patients respectively. Peripheral blood, tumor tissue and adjacent normal tissue were also collected from two patients with benign breast tumor, and 1/2, 2/2 and 2/2 was detected to have HPV16 DNA respectively. MPS metrics including mapping ratio, coverage, depth and SNVs were provided to characterize HPV in samples. The average coverage was 69% and 61.2% for malignant and benign samples respectively. 126 SNVs were identified in all 9 samples. The maximum number of SNVs was located in the gene of E2 and E4 among all samples. Our study not only provided an efficient method to capture HPV DNA, but detected the SNVS, coverage, SNV type and depth. The finding has provided further clue of association between HPV16 and breast cancer.
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?ig-h3 promotes human osteosarcoma cells metastasis by interacting with integrin ?2?1 and activating PI3K signaling pathway.
PLoS ONE
PUBLISHED: 01-01-2014
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Osteosarcoma, the most common primary bone tumor in children and young adolescents, is characterized by local invasion and distant metastasis. But the detailed mechanisms of osteosarcoma metastasis are not well known. In the present study, we found that ?ig-h3 promotes metastatic potential of human osteosarcoma cells in vitro and in vivo. Furthermore, ?ig-h3 co-localized with integrin ?2?1 in osteosarcoma cells. But ?ig-h3 did not change integrin ?2?1 expression in Saos-2 cells. Interaction of ?ig-h3 with integrin ?2?1 mediates metastasis of human osteosarcoma cells. The second FAS1 domain of ?ig-h3 but not the first FAS1 domain, the third FAS1 domain or the fourth FAS1 domain mediates human osteosarcoma cells metastasis, which is the ?2?1 integrin-interacting domain. We further demonstrated that PI3K/AKT signaling pathway is involved in ?ig-h3-induced human osteosarcoma cells metastasis process. Together, these results reveal ?ig-h3 enhances the metastasis potentials of human osteosarcoma cells via integrin ?2?1-mediated PI3K/AKT signal pathways. The discovery of ?ig-h3-mediated pathway helps us to understand the mechanism of human osteosarcoma metastasis and provides evidence for the possibility that ?ig-h3 can be a potential therapeutic target for osteosarcoma treatment.
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Ginsenoside Rb1 ameliorates lipopolysaccharide-induced albumin leakage from rat mesenteric venules by intervening in both trans- and paracellular pathway.
Am. J. Physiol. Gastrointest. Liver Physiol.
PUBLISHED: 12-19-2013
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Lipopolysaccharide (LPS) is one of the common pathogens which causes mesentery hyperpermeability and intestinal edema related diseases. This study evaluated whether ginsenoside Rb1 (Rb1), an ingredient of a Chinese medicine Panax ginseng, has beneficial effects on mesentery microvascular hyperpermeability induced by LPS and the underlying mechanisms. Male Wistar rats were continuously infused with LPS (5 mg/kg/hr) via the left jugular vein for 90 min. In some rats, Rb1 (5 mg/kg/hr) was administrated through the left jugular vein 30 min after LPS infusion. The dynamics of fluorescein isothiocynate-labeled albumin leakage from mesentery venules was assessed by intravital microscopy. Intestinal tissue edema was evaluated by hematoxylin and eosin staining. The number of caveolae in endothelial cells of microvessels was examined by electron microscopy. Confocal microscopy and Western blotting were applied to detect caveolin-1 (Cav-1) expression and phosphorylation, junction-related proteins, and concerning signaling proteins in intestinal tissues and human umbilical vein endothelial cells. LPS infusion evoked an increased albumin leakage from mesentery venules, which was significantly ameliorated by Rb1 post-treatment. Mortality and intestinal edema around microvessels were also reduced by Rb1. Rb1 decreased caveolae number in endothelial cells of microvessels. Cav-1 expression and phosphorylation, VE-Cadherin phosphorylation, ZO-1 degradation, nuclear factor-kappa B (NF-?B) activation and Src kinase phosphorylation were inhibited by Rb1. Rb1 ameliorated microvascular hyperpermeability after the onset of endotoxemia and improved intestinal edema through inhibiting caveolae formation and junction disruption, which was correlated to suppression of NF-?B and Src activation.
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Multiple Rice miRNAs Are Involved in Immunity against the Blast Fungus Magnaporthe oryzae.
Plant Physiol.
PUBLISHED: 12-13-2013
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MicroRNAs (miRNAs) are indispensable regulators for development and defense in eukaryotes. However, the miRNA species have not been explored for rice immunity against the blast fungus Magnaporthe oryzae, the most devastating fungal pathogen in rice production worldwide. Here, by deep sequencing small RNA (sRNA) libraries from susceptible and resistant lines at normal conditions and upon M. orzyzae infection, we identified a group of known rice miRNAs that were differentially expressed upon M. oryzae infection. They were further classified into three classes based on their expression patterns in the susceptible line LTH (Lijiangxin Tuan Hegu, Oryza sativa L. japonica) and in the resistant line IRBLkm-Ts that contains a single resistance gene locus Pikm within LTH background. RNA-blotting assay on nine of them confirmed sequencing results. Real-time reverse transcription (RT) PCR assay showed the expressions of a part of target genes were negatively correlated with the expressions of miRNAs. Moreover, transgenic rice plants over-expressing miR160a and miR398b displayed enhanced resistance to M. oryzae as demonstrated by decreased fungal growth, increased H2O2 accumulation at the infection site and up-regulated expression of defense-related genes. Taken together, our data indicate that miRNAs are involved in rice immunity against M. oryzae and over-expression of miR160a or miR398b can enhance rice resistance to the disease.
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Protective effects of Notoginsenoside R1 on intestinal ischemia/reperfusion injury in rats.
Am. J. Physiol. Gastrointest. Liver Physiol.
PUBLISHED: 11-14-2013
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Intestinal ischemia and reperfusion (I/R) is a clinical problem occurred for diverse causes with high mortality. Prophylaxis and treatment of intestinal I/R remains a challenge for clinician. The present study was to explore the role of Notoginsenoside R1 (R1), a major component form Panax. Notoginseng, in management of intestinal I/R injury. Intestinal I/R was induced in male Sprague-Dawley rats by clamping the superior mesenteric artery for 90 min followed by reperfusion for 60 min or 3 days. R1 (10 mg/kg/h) was administered either 20 min before ischemia or 20 min after reperfusion. Intestinal microcirculation was evaluated by intravital microscopy over 60 min reperfusion. Sixty min or 3 days after reperfusion, rats were killed for histological examination of the jejunum tissue and immunohistochemical localization of myeloperoxidase and CD68. ATP, ADP and AMP content in jejunum tissue was assessed by ELISA. Activation of NF-?B, expression of ATP5D and tight junction proteins were determined by Western blotting. The results demonstrated that R1 is capable of attenuating intestinal I/R-induced microvascular hyperpermeability, inflammatory cytokine production, NF-?B activation and loss of tight junction proteins, as well as improving energy metabolism during I/R. The results of the present study suggest R1 as an option in protecting against intestinal I/R injury.
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Regulation of photosynthetic performance and antioxidant capacity by (60)Co ?-irradiation in Zizania latifolia plants.
J Environ Radioact
PUBLISHED: 11-10-2013
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The aim of the present work was to investigate the photosynthetic performance and antioxidant enzyme activities in response to ?-irradiation of an aquatic plant Zizania latifolia. The Z. latifolia seedlings at 6-leaf stage were exposed to 25, 50 and 100 Gy of ? rays from a (60)Co source. The growth parameters, chlorophyll contents, photosynthetic gas exchange, chlorophyll fluorescence, malondialdehyde (MDA) content, antioxidant enzyme activities and antioxidant contents were examined at 1-5 weeks post-irradiation (WPI). The results showed that plant height, leaf number and tiller (branch close to ground) number were significantly suppressed by 50 and 100 Gy irradiation at 5, 3-5 and 4-5 WPI, respectively, but they were not significantly different from control by 25 Gy irradiation. Chlorophyll a, chlorophyll b, and total chlorophyll contents were also found to be significantly decreased by irradiation. The net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO2 concentration (Ci) and transpiration rate (Tr) generally declined in a dose-dependent manner. As for the chlorophyll fluorescence parameters, maximum quantum efficiency of PSII photochemistry (Fv/Fm), actual photochemical efficiency of PSII (?PSII) and photochemical quenching (qP) were observed to be significantly decreased compared to the control at 3 WPI, while non-photochemical quenching (NPQ) significantly increased by 100 Gy. ?-irradiation induced substantial increase in MDA content, ascorbate peroxidase (APX) activity, reduced ascorbate (AsA) content and reduced glutathione (GSH) content, suggesting a protective mechanism of Z. latifolia plant against oxidative stress when exposed to ?-irradiation.
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[Study on preparation process and stability of beta-cyclodextrin inclusion compound in volatile oil of Cinnamomum longepaniculatum leaves].
Zhongguo Zhong Yao Za Zhi
PUBLISHED: 10-02-2013
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To study the optimum preparation process and stability of beta-cyclodextrin inclusion compound in volatile oil of Cinnamomum longepaniculatum leaves. The saturated aqueous solution method was adopted to prepare inclusion compounds for an orthogonal test. The inclusion compound productivity and the inclusion rate were taken as indexes for screening the inclusion processes. The inclusion effect was evaluated with the infrared spectrophotometry and TLC, and the stability under conditions of high temperature, high humidity and strong light was detected. Under optimum preparation conditions for inclusion, the ratio between volatile oil and beta-cyclodextrin was 1: 8 (mL: g), that between beta-cyclodextrin and water was 1: 15, the inclusion temperature was 40 degrees C, and the inclusion time was 3 h. The results of spectrophotometry and TLC showed that the optimum conditions can generate beta-cyclodextrin inclusion compound in volatile oil of C. longepaniculatum leaves with certain light resistance, thermo-stability and hygro-stability. Therefore the optimum inclusion process features simple operation and stable inclusion compounds.
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New monoclinic phase at the composition Cu2SnSe3 and its thermoelectric properties.
Inorg Chem
PUBLISHED: 09-18-2013
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A new monoclinic phase (m2) of ternary diamond-like compound Cu2SnSe3 was synthesized by reaction of the elements at 850 K. The crystal structure of m2-Cu2SnSe3 was determined through electron diffraction tomography and refined by full-profile techniques using synchrotron X-ray powder diffraction data (space group Cc, a = 6.9714(2) Å, b = 12.0787(5) Å, c = 13.3935(5) Å, ? = 99.865(5)°, Z = 8). Thermal analysis and annealing experiments suggest that m2-Cu2SnSe3 is a low-temperature phase, while the high-temperature phase has a cubic crystal structure. According to quantum chemical calculations, m2-Cu2SnSe3 is a narrow-gap semiconductor. A study of the chemical bonding, applying the electron localizability approach, reveals covalent polar Cu-Se and Sn-Se interactions in the crystal structure. Thermoelectric properties were measured on a specimen consolidated using spark plasma sintering (SPS), confirming the semiconducting character. The thermoelectric figure of merit ZT reaches a maximum value of 0.33 at 650 K.
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Fatty acid labeling from glutamine in hypoxia can be explained by isotope exchange without net reductive isocitrate dehydrogenase (IDH) flux.
J. Biol. Chem.
PUBLISHED: 09-12-2013
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Acetyl-CoA is an important anabolic precursor for lipid biosynthesis. In the conventional view of mammalian metabolism, acetyl-CoA is primarily derived by the oxidation of glucose-derived pyruvate in mitochondria. Recent studies have employed isotope tracers to show that in cancer cells grown in hypoxia or with defective mitochondria, a major fraction of acetyl-CoA is produced via another route, reductive carboxylation of glutamine-derived ?-ketoglutarate (catalyzed by reverse flux through isocitrate dehydrogenase, IDH). Here, we employ a quantitative flux model to show that in hypoxia and in cells with defective mitochondria, oxidative IDH flux persists and may exceed the reductive flux. Therefore, IDH flux may not be a net contributor to acetyl-CoA production, although we cannot rule out net reductive IDH flux in some compartments. Instead of producing large amounts of net acetyl-CoA reductively, the cells adapt by reducing their demand for acetyl-CoA by importing rather than synthesizing fatty acids. Thus, fatty acid labeling from glutamine in hypoxia can be explained by spreading of label without net reductive IDH flux.
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Monolithic graphene fibers for solid-phase microextraction.
J Chromatogr A
PUBLISHED: 08-29-2013
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Monolithic graphene fibers for solid-phase microextraction (SPME) were fabricated through a dimensionally confined hydrothermal strategy and their extraction performance was evaluated. For the fiber fabrication, a glass pipeline was innovatively used as a hydrothermal reactor instead of a Teflon-lined autoclave. Compared with conventional methods for SPME fibers, the proposed strategy can fabricate a uniform graphene fiber as long as several meters or more at a time. Coupled to capillary gas chromatography (GC), the monolithic graphene fibers in a direct-immersion (DI) mode achieved higher extraction efficiencies for aromatics than those for n-alkanes, especially for polycyclic aromatic hydrocarbons (PAHs), thanks to ?-? stacking interaction and hydrophobic effect. Additionally, the fibers exhibited excellent durability and can be repetitively used more than 160 times without significant loss of extraction performance. As a result, an optimum extraction condition of 40°C for 50min with 20% NaCl (w/w) was finally used for SPME of PAHs in aqueous samples. For the determination of PAHs in water samples, the proposed DI-SPME-GC method exhibited linear range of 0.05-200?g/L, limits of detection (LOD) of 4.0-50ng/L, relative standard deviation (RSD) less than 9.4% and 12.1% for one fiber and different fibers, respectively, and recoveries of 78.9-115.9%. The proposed method can be used for analysis of PAHs in environmental water samples.
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A Subanesthetic Dose of Isoflurane during Postconditioning Ameliorates Zymosan-Induced Neutrophil Inflammation Lung Injury and Mortality in Mice.
Mediators Inflamm.
PUBLISHED: 08-16-2013
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Anesthetic isoflurane (ISO) has immunomodulatory effects. In the present study, we investigated whether a subanesthetic dose of ISO (0.7%) protected against zymosan (ZY) induced inflammatory responses in the murine lung and isolated neutrophils. At 1 and 6?hrs after ZY administration intraperitoneally, ISO was inhaled for 1?hr, and 24?hrs later, lung inflammation and injury were assessed. We found that ISO improved the survival rate of mice and mitigated lung injury as characterized by the histopathology, wet-to-dry weight ratio, protein leakage, and lung function index. ISO significantly attenuated ZY-induced lung neutrophil recruitment and inflammation. This was suggested by the downregulation of (a) endothelial adhesion molecule expression and myeloperoxidase (MPO) activity in lung tissue and polymorphonuclear neutrophils (b) chemokines, and (c) proinflammatory cytokines in BALF. Furthermore, ZY-induced nuclear translocation and DNA-binding activity of NF- ? B p65 were also reduced by ISO. ISO treatment inhibited iNOS expression and activity, as well as subsequent nitric oxide generation. Consistent with these in vivo observations, in vitro studies confirmed that ISO blocked NF- ? B and iNOS activation in primary mouse neutrophils challenged by ZY. These results provide evidence that 0.7% ISO ameliorates inflammatory responses in ZY-treated mouse lung and primary neutrophils.
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Functional identification of multiple nucleocytoplasmic trafficking signals in the broad-spectrum resistance protein RPW8.2.
Planta
PUBLISHED: 08-14-2013
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Nuclear localization signals (NLSs) and nuclear export signals (NESs) are important intramolecular regulatory elements for protein nucleocytoplasmic trafficking. This regulation confers spatial specificity to signal initiation and transduction in eukaryotic cells and thus is fundamental to the viability of all eukaryotic organisms. Here, we developed a simple and rapid method in which activity of putative NLSs or NESs was reported by subcellular localization of two tandem fluorescent proteins in fusion with the respective NLSs or NESs after agroinfiltration-mediated transient expression in leaves of Nicotiana benthamiana (Nb). We further demonstrated that the predicted NES from amino acid residue (aa) 9 to 22 and the NLS from aa91 to 101 in the broad-spectrum disease resistance protein RPW8.2 possess nuclear export and import activity, respectively. Additionally, by testing overlapping fragments covering the full length of RPW8.2, we identified another NLS from aa65 to 74 with strong nuclear import activity and two tandem non-canonical NESs in the C-terminus with strong nuclear export activity. Taken together, our results demonstrated the utility of a simple method to evaluate potential NLSs and NESs in plant cells and suggested that RPW8.2 may be subject to opposing nucleocytoplasmic trafficking forces for its subcellular localization and functional execution.
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[Quality of life of inpatients with coal workers pneumoconiosis and its influential factors].
Zhonghua Lao Dong Wei Sheng Zhi Ye Bing Za Zhi
PUBLISHED: 08-03-2013
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To investigate the quality of life ( QOL) of inpatients with coal workers pneumoconiosis( CWP) and analyse its influential factors, and to provide a theoretical basis for effective control measures.
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Vegetarian dietary patterns and mortality in Adventist Health Study 2.
JAMA Intern Med
PUBLISHED: 07-10-2013
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Some evidence suggests vegetarian dietary patterns may be associated with reduced mortality, but the relationship is not well established.
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Characterization of three cryptic plasmids from Lactobacillus plantarum G63 that was isolated from Chinese pickle.
Plasmid
PUBLISHED: 06-30-2013
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Three plasmids from Lactobacillus plantarum G63, pG6301, pG6302 and pG6303, were sequenced and have molecular sizes of 3516-bp, 9112-bp and 10047-bp, respectively. We determined the replicons of these plasmids. The pG6301 plasmid carried a replication gene that functioned by the rolling-circle replication mechanism. The Rep protein of pG6302 shared extremely low similarity with a reported plasmid, pLME300, which replicated by a bi-directional mechanism. Both the Rep protein and OriV analyses indicated a similar replication mechanism in pG6302. Conversely, we found neither the Rep protein nor OriV when we analyzed the whole sequence of pG6303. This finding may illustrate a novel replication mechanism. Additionally, the transposon, a mobilization element, was analyzed and compared to a similar insertion sequence (IS) element. A predicted lysozyme gene, pG6303 guhA, was heterologously expressed, but no activity was detected. The pG6302 and pG6303 plasmids contain new replicons and may be useful vector candidates for future molecular manipulation of L. plantarum.
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Structure determination of ultra dense magnesium borohydride: a first-principles study.
J Chem Phys
PUBLISHED: 06-14-2013
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Magnesium borohydride (Mg(BH4)2) is one of the potential hydrogen storage materials. Recently, two experiments [Y. Filinchuk, B. Richter, T. R. Jensen, V. Dmitriev, D. Chernyshov, and H. Hagemann, Angew. Chem., Int. Ed. 50, 11162 (2011); L. George, V. Drozd, and S. K. Saxena, J. Phys. Chem. C 113, 486 (2009)] found that ?-Mg(BH4)2 can irreversibly be transformed to an ultra dense ?-Mg(BH4)2 under high pressure. Its volumetric hydrogen content at ambient pressure (147 g/cm(3)) exceeds twice of DOEs (U.S. Department of Energy) target (70 g/cm(3)) and that of ?-Mg(BH4)2 (117 g/cm(3)) by 20%. In this study, the experimentally proposed P4(2)nm structure of ?-phase has been found to be dynamically unstable. A new Fddd structure has been reported as a good candidate of ?-phase instead. Its enthalpy from 0 to 12 GPa is much lower than P4(2)nm structure and the simulated X-ray diffraction spectrum is in satisfied agreement with previous experiments. In addition, the previously proposed P-3m1 structure, which is denser than Fddd, is found to be a candidate of ?-phase due to the agreement of Raman shifts.
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Astragaloside IV protects heart from ischemia and reperfusion injury via energy regulation mechanism.
Microcirculation
PUBLISHED: 06-08-2013
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This study was designed to investigate the protective potential of AS-IV against ischemia and I/R induced myocardial damage, with focusing on possible involvement of energy metabolism modulation in its action and the time phase in which it takes effect.
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CE-MS based on moving reaction boundary method for urinary metabolomic analysis of gastric cancer patients.
Electrophoresis
PUBLISHED: 05-25-2013
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There is still a lack of satisfactory tumor markers for gastric cancer (GasC). This study is aimed at optimizing parameters in CE-MS based on moving reaction boundary (MRB) so as to improve its sensitivity and stability, and at searching for potential tumor markers of GasC in patients urine samples via MRB-CE-MS. In this study, several parameters of MRB-CE-MS were investigated and optimized in order to gain optimal stability, sensitivity, and specificity, and was afterwards evaluated as valid. Subsequently, urine samples from GasC patients and control subjects were subjected to MRB-CE-MS analysis under optimized conditions, which successfully distinguished GasC patients from controls, as well as early-stage patients from advanced stage patients. Differentiation performance was evaluated by area under the curve, which showed fine differential value between GasC patients and controls, as well as between early and advanced stage patients (area under the curve value 1.0 and 0.847, respectively). In conclusion, this study established a set of feasible and useful methodology in searching potential tumor markers in urine samples from GasC patients. Moreover, several amino acids have been recognized as potential tumor markers that deserve further investigation.
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Identification of two novel waxy alleles and development of their molecular markers in sorghum.
Genome
PUBLISHED: 05-23-2013
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High amylopectin grains of waxy sorghum have a high economic value in the food and bioenergy industries because of their increased starch digestibility and higher ethanol conversion rate compared with wild-type sorghum grains. Mutation in the granule-bound starch synthase (GBSS) gene contributes to the waxy phenotype. Two classes of waxy alleles, wx(a) and wx(b), have been characterized previously. In the present work, we identified two novel types of waxy mutations in the sorghum GBSS gene, designated as wx(c) and wx(d). The wx(c) allele has a G deletion at the 5 splicing site of the ninth intron, causing a shift of the 5 cleavage site; in turn, a reading frame shift occurred and resulted in an early translation termination. The wx(d) allele contained a mutation at the 3 splicing site of the 10th intron, which led to a splicing site shift and resulted in the deletion of five amino acids (GTGKK) in the predicted translation product. Furthermore, cleaved amplified polymorphic sequence (CAPS) markers were developed to detect the wx(c) and wx(d) alleles. With these markers, classification of waxy alleles was performed in nearly 100 sorghum accessions from our breeding program. Most waxy sorghum cultivars in China were either wx(a) or wx(c), implying that these two mutations are preferentially maintained during domestic selection in glutinous sorghum production.
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Glutamine-driven oxidative phosphorylation is a major ATP source in transformed mammalian cells in both normoxia and hypoxia.
Mol. Syst. Biol.
PUBLISHED: 05-17-2013
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Mammalian cells can generate ATP via glycolysis or mitochondrial respiration. Oncogene activation and hypoxia promote glycolysis and lactate secretion. The significance of these metabolic changes to ATP production remains however ill defined. Here, we integrate LC-MS-based isotope tracer studies with oxygen uptake measurements in a quantitative redox-balanced metabolic flux model of mammalian cellular metabolism. We then apply this approach to assess the impact of Ras and Akt activation and hypoxia on energy metabolism. Both oncogene activation and hypoxia induce roughly a twofold increase in glycolytic flux. Ras activation and hypoxia also strongly decrease glucose oxidation. Oxidative phosphorylation, powered substantially by glutamine-driven TCA turning, however, persists and accounts for the majority of ATP production. Consistent with this, in all cases, pharmacological inhibition of oxidative phosphorylation markedly reduces energy charge, and glutamine but not glucose removal markedly lowers oxygen uptake. Thus, glutamine-driven oxidative phosphorylation is a major means of ATP production even in hypoxic cancer cells.
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Hypoxic and Ras-transformed cells support growth by scavenging unsaturated fatty acids from lysophospholipids.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 05-13-2013
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Cancer cell growth requires fatty acids to replicate cellular membranes. The kinase Akt is known to up-regulate fatty acid synthesis and desaturation, which is carried out by the oxygen-consuming enzyme stearoyl-CoA desaturase (SCD)1. We used (13)C tracers and lipidomics to probe fatty acid metabolism, including desaturation, as a function of oncogene expression and oxygen availability. During hypoxia, flux from glucose to acetyl-CoA decreases, and the fractional contribution of glutamine to fatty acid synthesis increases. In addition, we find that hypoxic cells bypass de novo lipogenesis, and thus, both the need for acetyl-CoA and the oxygen-dependent SCD1-reaction, by scavenging serum fatty acids. The preferred substrates for scavenging are phospholipids with one fatty acid tail (lysophospholipids). Hypoxic reprogramming of de novo lipogenesis can be reproduced in normoxic cells by Ras activation. This renders Ras-driven cells, both in culture and in allografts, resistant to SCD1 inhibition. Thus, a mechanism by which oncogenic Ras confers metabolic robustness is through lipid scavenging.
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Bone marrow-derived mesenchymal stem cells promote hepatic regeneration after partial hepatectomy in rats.
Pathobiology
PUBLISHED: 04-22-2013
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Our goal was to study the ability of mesenchymal stem cells (MSCs) to stimulate liver regeneration after partial hepatectomy in rats.
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