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Find video protocols related to scientific articles indexed in Pubmed.
Ionizing Radiation Sensitizes Breast Cancer Cells to Bcl-2 Inhibitor, ABT-737, through Regulating Mcl-1.
Radiat. Res.
PUBLISHED: 11-20-2014
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Breast-conserving surgery followed by radiation therapy has become the standard of care for early stage breast cancer. However, there are some patients that develop a local failure. We have previously shown that Bcl-2 overexpression was associated with an increased risk of local recurrence in patients with early stage breast cancer. The purpose of this study was to explore an approach to overcome radiation resistance by targeting pro-survival Bcl-2 family proteins in breast cancer cells. The breast cancer cell lines MCF-7, ZR-75-1 and MDA-MB231 were used in this study. siRNAs were employed to silence myeloid cell leukemia 1 (Mcl-1). A small molecule inhibitor of Bcl-2, ABT-737, was used to target anti-apoptotic Bcl-2 family proteins. Apoptosis was identified by FITC Annexin V, PI staining and Western blot analysis. The sensitivity to ionizing radiation and ABT-737 were measured by clonogenic assays. The effect of radiation and ABT-737 was also tested in a MCF-7 xenograft mouse model. Our data demonstrate that the combination of ABT-737 and radiation-induced apoptosis had an inhibitory effect on breast cancer cell proliferation. However, treatment with ABT-737 resulted in elevated Mcl-1 in breast cancer cell lines. Targeting Mcl-1 by siRNA sensitized MCF-7 cells to ABT-737. We revealed that radiation blunted Mcl-1 elevation induced by ABT-737, and that radiation downregulated Mcl-1 by promoting its degradation. Our results indicate that radiation and ABT-737 exert a synergistic effect on breast cancer cell lines through downregulating Mcl-1 and activating the bak-apoptotic pathway. These results support the combination of radiation and pro-survival Bcl-2 family inhibitor as a potential novel therapeutic strategy in the local-regional management of breast cancer.
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Bulk Charge Carrier Transport in Push-Pull type Organic Semiconductor.
ACS Appl Mater Interfaces
PUBLISHED: 11-14-2014
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Operation of organic electronic and optoelectronic devices relies on charge transport properties of active layer materials. The magnitude of charge carrier mobility, a key efficiency metrics of charge transport properties, is determined by the chemical structure of molecular units and their crystallographic packing motifs, as well as strongly depends on the film fabrication approaches that produce films with different degrees of anisotropy and structural order. Probed by the time-of-flight and grazing incidence X-ray diffraction techniques, bulk charge carrier transport, molecular packing and film morphology in different structural phases of push-pull type organic semiconductor, 7,7'-(4,4-bis(2-ethylhexyl)-4H-silolo[3,2-b:4,5-b']dithiophene-2,6-diyl)bis(6-fluoro-4-(5'-hexyl-[2,2'-bithiophen]-5yl)benzo[c][1,2,5] thiadiazole), one of the most efficient small-molecule photovoltaic materials to-date, are described herein. In the isotropic phase, the material is ambipolar with high mobilities for a fluid state. The electron and hole mobilities at the phase onset at 210.78 °C are 1.0×10-3 cm2/Vs and 6.5×10-4 cm2/Vs, respectively. Analysis of the temperature and electric field dependences of the mobilities in the framework of Gaussian disorder formalism suggests larger energetic and positional disorder for electron transport sites. Below 210 °C, crystallization into a polycrystalline film with a triclinic unit cell symmetry and high degree of anisotropy leads to a 10-fold increase of hole mobility. The mobility is limited by the charge transfer along the direction of branched alkyl side chains. Below 90 °C, faster cooling rates produce even higher hole mobilities up to 2×10-2 cm2/Vs at 25 °C due to more isotropic orientations of crystalline domains. These properties facilitate in understanding efficient material performance in photovoltaic devices and will guide further development of materials and devices.
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Synthesis and Biological Evaluation of Sophoridinol Derivatives as a Novel Family of Potential Anticancer Agents.
ACS Med Chem Lett
PUBLISHED: 11-13-2014
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New N-substituted sophoridinic acid/ester and sophoridinol derivatives were synthesized and evaluated for their cytotoxic activity in human HepG2 hepatoma cells from the lead sophoridine (1). Among the newly synthesized compounds, sophoridinol 7i displayed a potential antiproliferative activity with an IC50 of 3.1 ?M. Importantly, it exerted an almost equipotent effect against both wild MCF-7 and adriamycin (AMD)-resistant MCF-7 (MCF-7/AMD) breast carcinoma cell lines. Its mode of action was to arrest the cell cycle at the G0/G1 phase, consistent with that of the parent 1. In addition, compound 7i also showed a reasonable ClogP value and favorable pharmacokinetic property with an area under the concentration-time curve (AUC) of 10.3 ?M·h in rats, indicating an ideal druggable characteristic. We consider sophoridinol derivatives to be a novel family of promising antitumor agents with an advantage of inhibiting drug-resistant cancer cells.
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RAD6 promotes homologous recombination repair by activating the autophagy-mediated degradation of heterochromatin protein HP1.
Mol. Cell. Biol.
PUBLISHED: 11-12-2014
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Efficient DNA double-strand break (DSB) repair is critical for the maintenance of genome stability. Unrepaired or mis-repaired DSBs cause chromosomal rearrangements that can result in severe consequences such as tumorigenesis. RAD6 is an E2 ubiquitin-conjugating enzyme that plays a pivotal role in repairing UV-induced DNA damage. Here, we present evidence that RAD6 is also required for DNA DSB repair via homologous recombination (HR) by specifically regulating the degradation of heterochromatin protein 1? (HP1?). Our study indicates that RAD6 physically interacts with HP1? and ubiquitinates HP1? at residue K154, thereby promoting HP1? degradation through the autophagy pathway and eventually leading to an open chromatin structure that facilitates efficient HR DSB repair. Furthermore, bioinformatics studies have indicated that the expression of RAD6 and HP1? exhibits an inverse relationship and correlates with the survival rate of patients.
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[Clinical outcome of deep sternal wound infection after cardiac surgery].
Zhonghua Wai Ke Za Zhi
PUBLISHED: 11-06-2014
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To retrospectively evaluate the results of deep sternal wound infection (DSWI) after cardiac surgery.
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Molecular Weight Dependence of the Morphology in P3HT:PCBM Solar Cells.
ACS Appl Mater Interfaces
PUBLISHED: 10-29-2014
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In polymer-based photovoltaic devices, optimizing and controlling the active layer morphology is important to enhancing the device efficiency. Using poly(3-hexylthiophene) (P3HT) with well-defined molecular weights (MWs), synthesized by the Grignard metathesis (GRIM) method, we show that the morphology of the photovoltaic active layer and the absorption and crystal structure of P3HT are dependent on the MW. Differential scanning calorimetry showed that the crystallinity of P3HT reached a maximum for intermediate MWs. Grazing-incidence wide-angle X-ray diffraction showed that the spacing of the (100) planes of P3HT increased with increasing MW, while the crystal size decreased. Nonlinear crystal lattice expansions were found for both the (100) and (020) lattice planes, with an unusual ?-?-stacking enhancement observed between 50 and 100 °C. The melting point depression for P3HT, when mixed with [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), and, hence, the Flory-Huggins interaction parameter depended on the MW. PCBM was found to perturb the ordering of P3HT chains. In photovoltaic devices, P3HT with a MW of ?20K showed the best device performance. The morphologies of these blends were studied by grazing-incidence small-angle X-ray scattering (GISAXS) and resonant soft X-ray scattering. In GISAXS, we observed that the low-molecular-weight P3HT more readily crystallizes, promoting a phase-separated morphology.
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[Evaluation on implementation effect of Malaria Elimination Project supported by Global Fund in Shaanxi Province].
Zhongguo Xue Xi Chong Bing Fang Zhi Za Zhi
PUBLISHED: 10-28-2014
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To evaluate the implementation effect of Malaria Elimination Project supported by the Global Fund in Shaanxi Province so as to provide the evidence for the scientific implementation of Malaria Elimination Action Plan and the examination and evaluation work.
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Detection of Up-converted Persistent Luminescence in the Near Infrared Emitted by the Zn_{3}Ga_{2}GeO_{8}:Cr^{3+}, Yb^{3+}, Er^{3+} Phosphor.
Phys. Rev. Lett.
PUBLISHED: 10-21-2014
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Up-conversion luminescence and long-persistent luminescence are two well-studied, special luminescence processes. By combining the unique features of these two luminescence processes, here we design a new luminescence process called up-converted persistent luminescence (UCPL), which enables us to generate persistent luminescence having an emission energy higher than the excitation energy. Guided by the UCPL concept, we create the first UCPL phosphor Zn_{3}Ga_{2}GeO_{8}:1%Cr^{3+}, 5%Yb^{3+}, 0.5%Er^{3+} by incorporating an up-converting ion pair Yb^{3+}/Er^{3+} into a Zn_{3}Ga_{2}GeO_{8}:1%Cr^{3+} near-infrared persistent phosphor. After being excited by a 980 nm laser, the phosphor emits long-lasting (>24??h) near-infrared persistent emission peaking at 700 nm. The UCPL concept and the associated phosphors are expected to have important implications for several fields such as biomedical imaging.
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Increased functional connectivity strength of right inferior temporal gyrus in first-episode, drug-naive somatization disorder.
Aust N Z J Psychiatry
PUBLISHED: 10-15-2014
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Evidence of brain structural and functional alterations have been implicated in patients with somatization disorder (SD). However, little is known about brain functional connectivity in SD. In the present study, resting-state functional magnetic resonance imaging (fMRI) and graph theory were used to obtain a comprehensive view of whole-brain functional connectivity and to investigate the changes of voxel-wise functional networks in patients with SD.
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Late onset temperature reduction can retard aging process in aged fish via a combined action of antioxidant system and IIS pathway.
Rejuvenation Res
PUBLISHED: 10-10-2014
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Two different mechanisms are considered to be related with aging. Cumulative molecular damage caused by reactive oxygen species (ROS), the by-products of oxidative phosphorylation, is one of these mechanisms (ROS concept). Deregulated nutrient sensing by insulin and insulin-like growth factor 1 (IGF-1) signaling (IIS) pathway is the second mechanism (IIS concept). Temperature reduction (TR) is known to modulate aging and prolong lifespan in a variety of organisms, but the mechanisms remain poorly defined. Here we first demonstrate that late onset TR from 26oC to 22oC extends mean lifespan and maximum lifespan by approximately 5.2 and 3 weeks, respectively, in the annual fish Nothobranchius guentheri. We then show that TR is able to decrease the accumulation of histological aging markers senescence-associated ?-galactosidase (SA-?-Gal) in the epithelium and lipofuscin (LF) in the liver, and to reduce the protein oxidation and lipid peroxidation levels in the muscle. We also show that TR can enhance the activities of catalase, glutathione peroxidase and superoxide dismutase, and stimulate the synthesis of SirT1 and FOXO, both of which are the downstream regulator of IIS pathway. Taken together, our findings suggest that late onset TR, a simple non-intrusion intervention, can retard aging process in aged fish, resulting in their lifespan extension, via a synergistic action of antioxidant system and IIS pathway. This also suggests that combined assessment of ROS concept and IIS concept will contribute to providing more comprehensive view of anti-aging process.
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Studies on pharmacokinetics and bioavailability of aminophylline in partridge chickens.
Eur J Drug Metab Pharmacokinet
PUBLISHED: 09-17-2014
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Veterinary medicine plays a significant role in the development of animal husbandry. Drugs residual in food would follow the food-chain coming into human body, which might bring hidden dangers to people. Chicken is the prime source of meat food, whose quality is important for our life and health. Therefore, it is necessary to realize the withdrawal period and establish an efficient, sensitive and accurate method for monitoring the metabolic process of drugs in chicken body. In this paper, the pharmacokinetics of aminophylline in partridge chicken after intravenous and oral administration was investigated using a sensitive high-performance liquid chromatography method. Plasma concentration-time profiles of aminophylline were analyzed by a non-compartmental model using Topfit 2.0. Following intravenous and oral administration, the peak concentrations (C max) were found to be (16.5 ± 3.0) µg/mL at (0.08 ± 0) h and (7.4 ± 1.5) µg/mL at (1.83 ± 1.11) h, respectively. The elimination half-time (t 1/2) after intravenous and oral administration were, respectively, (13.1 ± 4.17) h and (11.65 ± 1.14) h. Areas under the plasma concentration-time curve (AUC) were (209.6 ± 22.8) µg h mL(-1)(AUC0-t ) and (219.5 ± 28.3) µg h mL(-1) (AUC0?? ) after intravenous, and (165.1 ± 37.0) µg h mL(-1)(AUC0-t ) and (179.3 ± 35.6) µg h mL(-1) (AUC0?? ) after oral administration. Mean retention time (MRT) after intravenous and oral administration were, respectively, (14.06 ± 0.86) and (15.27 ± 0.62) h. The total clearance rates (CLtol) were (0.77 ± 0.10) mL min(-1) kg(-1) of intravenous and (0.97 ± 0.20) mL min(-1) kg(-1) of oral administration. The apparent distribution volume (V d) was (0.87 ± 0.27) and (0.97 ± 0.20) L kg(-1), respectively, for intravenous and oral administration. The absolute bioavailability (F) after oral administration was (83.1 ± 11.7) %. The results showed that aminophylline in partridge chickens had a longer elimination half-time, a smaller clearance rate, as well as a higher absolute bioavailability for oral administration. Therefore, aminophylline in partridge chickens produced a long healing efficacy and oral administration can achieve a good absorption which could meet the requirement.
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A Small-Molecule Modulator of the Tumor-Suppressor miR34a Inhibits the Growth of Hepatocellular Carcinoma.
Cancer Res.
PUBLISHED: 09-12-2014
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Small molecules that restore the expression of growth-inhibitory microRNAs (miRNA) downregulated in tumors may have potential as anticancer agents. miR34a functions as a tumor suppressor and is downregulated or silenced commonly in a variety of human cancers, including hepatocellular carcinoma (HCC). In this study, we used an HCC cell-based miR34a luciferase reporter system to screen for miR34a modulators that could exert anticancer activity. One compound identified as a lead candidate, termed Rubone, was identified through its ability to specifically upregulate miR34a in HCC cells. Rubone activated miR34a expression in HCC cells with wild-type or mutated p53 but not in cells with p53 deletions. Notably, Rubone lacked growth-inhibitory effects on nontumorigenic human hepatocytes. In a mouse xenograft model of HCC, Rubone dramatically inhibited tumor growth, exhibiting stronger anti-HCC activity than sorafenib both in vitro and in vivo. Mechanistic investigations showed that Rubone decreased expression of cyclin D1, Bcl-2, and other miR34a target genes and that it enhanced the occupancy of p53 on the miR34a promoter. Taken together, our results offer a preclinical proof of concept for Rubone as a lead candidate for further investigation as a new class of HCC therapeutic based on restoration of miR34a tumor-suppressor function. Cancer Res; 74(21); 6236-47. ©2014 AACR.
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Human health risk assessment of pesticide residues in market-sold vegetables and fish in a northern metropolis of China.
Environ Sci Pollut Res Int
PUBLISHED: 09-09-2014
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With growing concerns about food safety and stricter national standards in China, attention has focused on vegetables and fish as they are an important part of the Chinese daily diet, and pesticide residues can accumulate in these foodstuffs. The local consumption habits of vegetables and fish were determined using questionnaires distributed in the major regions of the northern metropolis. Then, the samples of fruit-like vegetables, leafy and root vegetables, and five species of fish (freshwater and marine) were collected from supermarkets and traditional farmers' markets in the city. The concentrations and profiles of pesticide residues (hexachlorocyclohexane (HCH), dichlorodiphenyl trichloroethane (DDT), and endosulfan) in the samples were determined and compared. For the vegetables, the concentration ranges of ?DDT, ?HCH, and ?endosulfan were not detectable (ND) to 10.4 ng/g fresh weight (f.w.), ND to 58.8 ng/g f.w., and ND to 63.9 ng/g f.w., respectively. For the fish samples, the corresponding values were 0.77-25.0 ng/g f.w., 0.02-1.42 ng/g f.w., and 1.22-22.1 ng/g f.w., respectively. Only one celery sample exceeded the maximum residue limits (MRLs) of HCH residues set by Chinese regulations (GB2763-2014). The estimated daily intakes (EDIs) and hazard ratios (HRs) were calculated using data from the recently published Exposure Factors Handbook for the Chinese Population. The EDIs and HRs showed that the levels of organochlorine pesticide (OCP) residues in vegetables and fish in this area are safe.
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MicroRNA-339-5p inhibits colorectal tumorigenesis through regulation of the MDM2/p53 signaling.
Oncotarget
PUBLISHED: 09-07-2014
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Tumor suppressor p53 plays a central role in tumor suppression. To ensure its proper function, the levels and activity of p53 are under a tight regulation in cells. MicroRNAs are short non-coding RNAs that play an important role in regulation of gene expression. Recently, microRNA-339-5p has been reported to be frequently down-regulated in colorectal cancer, and furthermore, its down-regulation is associated with poor prognosis in cancer patients, which strongly suggests a tumor suppressive function of microRNA-339-5p in colorectal cancer. In this study, we found that microRNA-339-5p directly represses the expression of MDM2, a key negative regulator of p53, through binding to MDM2 3'-UTR in colorectal cancer cells. Through the down-regulation of MDM2, microRNA-339-5p increases p53 protein levels and functions, including p53 transcriptional activity and p53-mediated apoptosis and senescence in response to stress. Furthermore, microRNA-339-5p inhibits the migration and invasion of colorectal cancer cells and the growth of colorectal xenograft tumors in a largely p53-dependent manner. Our results highlighted an important role of microRNA-339-5p in suppression of colorectal tumorigenesis, and also revealed that regulating the p53 function is an important mechanism for microRNA-339-5p in tumor suppression.
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[Biomechanical study of the influence of stability for the pedicle screws fixation by injured vertebral screw when the pedicle cortex perforation].
Zhongguo Yi Xue Ke Xue Yuan Xue Bao
PUBLISHED: 09-02-2014
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To explore the impact of pedicle cortex perforation on the stability of internal fixation of the vertebral body fracture,and to compare the stability of the vertebrae with pedicle cortex perforation after the injured vertebra transpedicular screw fixation by different ways.
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Crystal structure of diethyl [(4-nitro-phenyl-amino)(2-hy-droxy-phen-yl)meth-yl]phospho-nate methanol monosolvate.
Acta Crystallogr Sect E Struct Rep Online
PUBLISHED: 09-01-2014
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In the title compound, C17H21N2O6P·CH3OH, the planes of the 4-nitro-aniline and 2-hy-droxy-phenyl groups form a dihedral angle of 84.04?(8)°. The P atom exhibits tetra-hedral geometry involving two O-ethyl groups, a C? atom and a double-bonded O atom. In the crystal, O-H?O, N-H?O and C-H?O hydrogen bonds link the ?-amino-phospho-nic acid and methanol mol-ecules into chains that propagate parallel to the a axis.
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Improving Enzymatic Hydrolysis of Corn Stover Pretreated by Ethylene Glycol-Perchloric Acid-Water Mixture.
Appl. Biochem. Biotechnol.
PUBLISHED: 08-30-2014
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To improve the enzymatic saccharification of lignocellulosic biomass, a mixture of ethylene glycol-HClO4-water (88.8:1.2:10, w/w/w) was used for pretreating corn stover in this study. After the optimization in oil-bath system, the optimum pretreatment temperature and time were 130 °C and 30 min, respectively. After the saccharification of 10 g/L pretreated corn stover for 48 h, the saccharification rate was obtained in the yield of 77.4 %. To decrease pretreatment temperature and shorten pretreatment time, ethylene glycol-HClO4-water (88.8:1.2:10, w/w/w) media under microwave irradiation was employed to pretreat corn stover effectively at 100 °C and 200 W for 5 min. Finally, the recovered hydrolyzates containing glucose obtained from the enzymatic hydrolysis of pretreated corn stovers could be fermented into ethanol efficiently. These results would be helpful for developing a cost-effective pretreatment combined with enzymatic saccharification of cellulosic materials for the production of lignocellulosic ethanol.
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A metabolic trade-off between phosphate and glucose utilization in Escherichia coli.
Mol Biosyst
PUBLISHED: 08-22-2014
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Getting the most out of available nutrients is a key challenge that all organisms face. Little is known about how they optimize and balance the simultaneous utilization of multiple elemental resources. We investigated the effects of long-term phosphate limitation on carbon metabolism of the model organism Escherichia coli using chemostat cultures. We profiled metabolic changes in the growth medium over time and found evidence for an increase in fermentative metabolism despite the aerobic conditions. Using full-genome sequencing and competition experiments, we found that fitness under phosphate-limiting conditions was reproducibly increased by a mutation preventing flux through succinate in the tricarboxylic acid cycle. In contrast, these mutations reduced competitive ability under carbon limitation, and thus reveal a conflicting metabolic benefit in the role of the TCA cycle in environments limited by inorganic phosphate and glucose.
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Fast quantification of endogenous carbohydrates in plasma using hydrophilic interaction liquid chromatography coupled with tandem mass spectrometry.
J Sep Sci
PUBLISHED: 08-19-2014
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Objective: Endogenous carbohydrates in biosamples are frequently highlighted as the most differential metabolites in many metabolomics studies. A simple, fast, simultaneous quantitative method for 16 endogenous carbohydrates in plasma has been developed using hydrophilic interaction liquid chromatography coupled with tandem mass spectrometry. Method: In order to quantify 16 endogenous carbohydrates in plasma, various conditions, including columns, chromatographic conditions, mass spectrometry conditions, and plasma preparation methods, were investigated. Different conditions in this quantified analysis were performed and optimized. The reproducibility, precision, recovery, and stability of the method were verified. Result: The results indicated that a methanol/acetonitrile (50:50, v/v) mixture could effectively and reproducibly precipitate rat plasma proteins. Cold organic solvents coupled with vortex for 1 min and incubated at -20°C for 20 min were the most optimal conditions for protein precipitation and extraction. The results, according to the linearity, recovery, precision, and stability, showed that the method was satisfactory in the quantification of endogenous carbohydrates in rat plasma. Conclusion: The quantified analysis of endogenous carbohydrates in rat plasma performed excellently in the sensitivity, high throughput and simple sample preparation, which met the requirement of quantification in specific expanded metabolomic studies after the global metabolic profiling research. This article is protected by copyright. All rights reserved.
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Tumor suppressor p53 negatively regulates glycolysis stimulated by hypoxia through its target RRAD.
Oncotarget
PUBLISHED: 08-13-2014
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Cancer cells display enhanced glycolysis to meet their energetic and biosynthetic demands even under normal oxygen concentrations. Recent studies have revealed that tumor suppressor p53 represses glycolysis under normoxia as a novel mechanism for tumor suppression. As a common microenvironmental stress for tumors, hypoxia drives the metabolic switch from the oxidative phosphorylation to glycolysis, which is crucial for survival and proliferation of cancer cells under hypoxia. The p53's role and mechanism in regulating glycolysis under hypoxia is poorly understood. Here, we found that p53 represses hypoxia-stimulated glycolysis in cancer cells through RRAD, a newly-identified p53 target. RRAD expression is frequently decreased in lung cancer. Ectopic expression of RRAD greatly reduces glycolysis whereas knockdown of RRAD promotes glycolysis in lung cancer cells. Furthermore, RRAD represses glycolysis mainly through inhibition of GLUT1 translocation to the plasma membrane. Under hypoxic conditions, p53 induces RRAD, which in turn inhibits the translocation of GLUT1 and represses glycolysis in lung cancer cells. Blocking RRAD by siRNA greatly abolishes p53's function in repressing glycolysis under hypoxia. Taken together, our results revealed an important role and mechanism of p53 in antagonizing the stimulating effect of hypoxia on glycolysis, which contributes to p53's function in tumor suppression.
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New localized/delocalized emitting state of Eu(2+) in orange-emitting hexagonal EuAl2O4.
Sci Rep
PUBLISHED: 08-12-2014
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Eu(2+)-activated phosphors are being widely used in illuminations and displays. Some of these phosphors feature an extremely broad and red-shifted Eu(2+) emission band; however, convincing explanation of this phenomenon is lacking. Here we report a new localized/delocalized emitting state of Eu(2+) ions in a new hexagonal EuAl2O4 phosphor whose Eu(2+) luminescence exhibits a very large bandwidth and an extremely large Stokes shift. At 77?K, two luminescent sites responsible for 550?nm and 645?nm broadband emissions are recognized, while at room temperature only the 645?nm emission band emits. The 645?nm emission exhibits a typical radiative lifetime of 1.27??s and an unusually large Stokes shift of 0.92?eV. We identify the 645?nm emission as originating from a new type of emitting state whose composition is predominantly that of localized 4f(6)5d character but which also contains a complementary component with delocalized conduction-band-like character. This investigation provides new insights into a unique type of Eu(2+) luminescence in solids whose emission exhibits both a very large bandwidth and an extremely large Stokes shift.
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Thermo-responsive release of curcumin from micelles prepared by self-assembly of amphiphilic P(NIPAAm-co-DMAAm)-b-PLLA-b-P(NIPAAm-co-DMAAm) triblock copolymers.
Int J Pharm
PUBLISHED: 07-24-2014
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Thermo-responsive micelles are prepared by self-assembly of amphiphilic triblock copolymers composed of a poly(l-lactide) (PLLA) central block and two poly(N-isopropylacrylamide-co-N,N-dimethylacrylamide) (P(NIPAAm-co-DMAAm)) lateral blocks, using solvent evaporation/film hydration method. The resulting micelles exhibit very low critical micelle concentration (CMC) which slightly increases from 0.0113 to 0.0144mgmL(-1) while the DMAAm content increases from 31.8 to 39.4% in the hydrophilic P(NIPAAm-co-DMAAm) blocks. The lower critical solution temperatures (LCST) of copolymers varies from 44.7°C to 49.4°C in water as determined by UV spectroscopy, and decreases by ca. 3.5°C in phosphate buffered saline (PBS). Curcumin was encapsulated in the core of micelles. High drug loading up to 20% is obtained with high loading efficiency (>94%). The LCST of drug loaded micelles ranges from 37.5 to 38.0°C with drug loading increasing from 6.0 to 20%. The micelles with diameters ranging from 47.5 to 88.2nm remain stable over one month due to the negative surface charge as determined by zeta potential (-12.4 to -18.7mV). Drug release studies were performed under in vitro conditions at 37°C and 40°C, i.e. below and above the LCST, respectively. Initial burst release is observed in all cases, followed by a slower release. The release rate is higher at 40°C than that at 37°C due to thermo-responsive release across the LCST. On the other hand, micelles with lower drug loading exhibit higher release rate than those with higher drug loading, which is assigned to the solubility effect. Peppas' theory was applied to describe the release behaviors. Moreover, the in vitro cytotoxicity of copolymers was evaluated using MTT assay. The results show that the copolymers present good cytocompatibility. Therefore, the nano-scale size, low CMC, high drug loading and stability, as well as good biocompatibility indicate that these thermo-responsive triblock copolymer micelles present a good potential as carrier for targeted delivery of anticancer drugs.
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Characterization of two UDP-Gal:GalNAc-diphosphate-lipid ?1,3-galactosyltransferases WbwC from Escherichia coli serotypes O104 and O5.
J. Bacteriol.
PUBLISHED: 06-23-2014
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Escherichia coli displays O antigens on the outer membrane that play an important role in bacterial interactions with the environment. The O antigens of enterohemorrhagic E. coli O104 and O5 contain a Gal?1-3GalNAc disaccharide at the reducing end of the repeating unit. Several other O antigens contain this disaccharide, which is identical to the mammalian O-glycan core 1 or the cancer-associated Thomsen-Friedenreich (TF) antigen. We identified the wbwC genes responsible for the synthesis of the disaccharide in E. coli serotypes O104 and O5. To functionally characterize WbwC, an acceptor substrate analog, GalNAc?-diphosphate-phenylundecyl, was synthesized. WbwC reaction products were isolated by high-pressure liquid chromatography and analyzed by mass spectrometry, nuclear magnetic resonance, galactosidase and O-glycanase digestion, and anti-TF antibody. The results clearly showed that the Gal?1-3GalNAc? linkage was synthesized, confirming WbwCECO104 and WbwCECO5 as UDP-Gal:GalNAc?-diphosphate-lipid ?1,3-Gal-transferases. Sequence analysis revealed a conserved DxDD motif, and mutagenesis showed the importance of these Asp residues in catalysis. The purified enzymes require divalent cations (Mn(2+)) for activity and are specific for UDP-Gal and GalNAc-diphosphate lipid substrates. WbwC was inhibited by bis-imidazolium salts having aliphatic chains of 18 to 22 carbons. This work will help to elucidate mechanisms of polysaccharide synthesis in pathogenic bacteria and provide technology for vaccine synthesis.
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Perspective on polychlorinated dibenzo-p-dioxin and dibenzofuran emissions during chemical production in China: an overlooked source of contemporary relevance.
Environ Sci Pollut Res Int
PUBLISHED: 06-07-2014
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Polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDDs/DFs) are pollutants of significant global concern, and China with its large size and industries is one of the main dioxin-emitting countries in the world. PCDDs/DFs may be formed during the manufacture of chemicals and can either remain in the products as impurities or be emitted into the environment or residues disposed to landfills. The uncertainties in the environmental emissions of PCDDs/DFs from the chemical production industry in China are large because of the complex nature of the industry and variability in the technologies used and limited monitoring conducted. In the current study, we used the PCDD/DF emission factor from the updated United Nations Environment Programme (UNEP) toolkit 2013, information from otherwise published data, and the chemical production data in 2010 to estimate PCDD/DF emissions from the chemical productions in China. Based on these data, it was estimated that there is 1480 g toxic equivalent (TEQ) from the chemical production industry in China, which is much higher than the value that was estimated and used in the national implementation plans (NIPs) for China (102.4 g TEQ in 2004). These results indicate that current PCDD/DF emissions from the chemical production industry in China may be overlooked. Therefore, we suggest that attention should be paid to PCDD/DF emissions from the chemical production industry in future updates of the Chinese NIP and that appropriate measures to decrease PCDD/DF emissions should be taken by better monitoring of products and processes in chemical production industry.
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High-throughput generation of an activation-tagged mutant library for functional genomic analyses in tobacco.
Planta
PUBLISHED: 05-27-2014
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Tobacco (Nicotiana tabacum L.) is an ideal model system for molecular biological and genetic studies. In this study, activation tagging was used to generate approximately 100,000 transgenic tobacco plants. Southern blot analysis indicated that there were 1.6 T-DNA inserts per line on average in our transformed population. The phenotypes observed include abnormalities in leaf and flower morphology, plant height, flowering time, branching, and fertility. Among 6,000 plants in the T0 generation, 57 displayed obvious phenotypes. Among 4,105 lines in the T1 generation, 311 displayed abnormal phenotypes. Fusion primer and nested integrated PCR was used to identify 963 independent genomic loci of T-DNA insertion sites in 1,257 T1 lines. The distribution of T-DNA insertions was non-uniform and correlated well with the predicted gene density along each chromosome. The insertions were biased toward genic regions and noncoding regions within 5 kb of a gene. Fifteen plants that showed the same phenotype as their parent with a dominant pattern in the T2 generation were chosen randomly to detect the expression levels of genes adjacent to the T-DNA integration sites by semi-quantitative RT-PCR. Fifteen candidate genes were identified. Activation was observed in 7 out of the 15 adjacent genes, including one that was located 13.1 kb away from the enhancer sequence. The activation-tagged population described in this paper will be a highly valuable resource for tobacco functional genomics research using both forward and reverse genetic approaches.
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Transcriptional adaptation of Shigella flexneri during adherence to epithelial cells.
J. Basic Microbiol.
PUBLISHED: 05-27-2014
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Shigella adhesion to host cells is a transitional stage from an extracellular to an intracellular environment. However, the dynamic adaptations of Shigella during adhesion are poorly understood. To address this, we performed the first transcriptome analysis of Shigella flexneri 2457T during adhesion. A total of 1,757 genes were differentially regulated (>twofold). The majority of plasmid-borne ipa-mxi-spa locus genes were downregulated, indicating these virulence genes were strictly regulated after successful adhesion. Altered expression of genes involved in stress response indicates that adherent S. flexneri encountered envelope stress and oxidative stress. Shigella flexneri also experienced reduced energy production during adherence. Transcript profiling and cell culture assays using glpD and glpK mutants showed that enhancement of glycerol catabolism were related with adhesion ability of S. flexneri. In addition, regulation of expression of some ionic transport system may be required for S. flexneri adhesion. Expression levels of 26 genes were further examined using qRT-PCR, which were congruent with transcriptome data. A comparison with expression profile during intracellular growth revealed major differences in genes involved in translation, surface modification, and utilization of carbon and iron. These results contribute to the knowledge of the adaptation mechanisms of S. flexneri during adhesion.
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A switch-like dynamic mechanism for the initiation of replicative senescence.
FEBS Lett.
PUBLISHED: 05-16-2014
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Telomeres are specialized structures protecting chromosomes against genome instability. Telomeres shorten with cell division, and replicative senescence is induced when telomeres are badly eroded. Whereas TRF2, ATM and p53 have been identified involved in senescence induction, how it is triggered remains unclear. Here, we propose an integrated model associating telomere loss with senescence trigger. We characterize the dynamics of telomere shorting and the p53-centered regulatory network. We show that senescence is initiated in a switch-like manner when both the shortest telomere becomes uncapped and the TRF2-ATM-p53-Siah1 positive feedback loop is switched on. This work provides a coherent picture of senescence induction in terms of telomere shortening and p53 activation.
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Metabolic engineering of Escherichia coli for poly(3-hydroxypropionate) production from glycerol and glucose.
Biotechnol. Lett.
PUBLISHED: 05-13-2014
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A new poly(3-hydroxypropionate) (P3HP) biosynthetic pathway employing ?-alanine as an intermediate from an inexpensive carbon source was developed in recombinant Escherichia coli. After a series of systematic optimization, the genes for L-aspartate decarboxylase and its maturation factor (panD and panM, from E. coli), ?-alanine-pyruvate transaminase (pp0596, from Pseudomonas putida), 3-hydroxy acid dehydrogenase and 3-hydroxypropionyl-CoA synthase (ydfG and prpE respectively, from E. coli), and polyhydroxyalkanoate synthase (phaC1, from Cupriavidus necator) were cloned and expressed in E. coli. Under shake-flask conditions, the recombinant strain produced 0.5 g P3HP l(-1) from glycerol and glucose, up to 10.2 % of CDW. Though the content of P3HP was low, this pathway has some advantages over other reported pathways, such as being redox neutral, does not require any coenzyme, and can use a wide range of carbon sources.
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Effect of microseparation on contact mechanics in metal-on-metal hip replacements-A finite element analysis.
J. Biomed. Mater. Res. Part B Appl. Biomater.
PUBLISHED: 05-12-2014
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Some early failures of metal-on-metal (MoM) hip replacements associated with elevated wear have caused concerns for the use of this bearing combination. Simulator studies have shown that microseparation and its associated rim contact and edge loading may produce the most severe wear in MoM bearings. It is generally recognized that this high wear can be attributed to the high contact stress of the head on the rim of the cup. In this study, an improved finite element contact model that incorporates an elastic-perfectly plastic material property for cobalt-chrome alloy of the metal bearing was developed in an attempt to provide an accurate prediction of the stress and strain for the rim contact. The effects of the microseparation displacement (0.1-2 mm), cup inclination angle (25-65°) and cup rim radius (0.5-4 mm) on the contact stress/strain were investigated. The results show that a translational displacement >0.1 mm under a load >0.5 kN can produce a highly concentrated contact stress at the surface of the cup rim which can lead to plastic deformation. This study also suggests that the magnitude of translational displacement was the major factor that determined the severity of the contact conditions and level of stress and strain under microseparation conditions. Future studies will address the effect of surgical translational and rotational malposition and component design on the magnitude of microseparation, contact stress and strain and severity of wear. © 2014 The Authors. Journal of Biomedical Materials Research Part B: Applied Biomaterials Published by Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2014.
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LIF negatively regulates tumour-suppressor p53 through Stat3/ID1/MDM2 in colorectal cancers.
Nat Commun
PUBLISHED: 05-08-2014
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Leukaemia inhibitory factor (LIF) has been recently identified as a p53 target gene, which mediates the role of p53 in maternal implantation under normal physiological conditions. Here we report that LIF is a negative regulator of p53; LIF downregulates p53 protein levels and function in human colorectal cancer (CRC) cells. The downregulation of p53 by LIF is mediated by the activation of Stat3, which transcriptionally induces inhibitor of DNA-binding 1 (ID1). ID1 upregulates MDM2, a key negative regulator of p53, and promotes p53 protein degradation. LIF is overexpressed in a large percentage of CRCs. LIF overexpression promotes cellular resistance towards chemotherapeutic agents in cultured CRC cells and colorectal xenograft tumours in a largely p53-dependent manner. Overexpression of LIF is associated with a poor prognosis in CRC patients. Taken together, LIF is a novel negative regulator of p53, overexpression of LIF is an important mechanism for the attenuation of p53, which promotes chemoresistance in CRCs.
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Formation of quantum spin Hall state on Si surface and energy gap scaling with strength of spin orbit coupling.
Sci Rep
PUBLISHED: 05-07-2014
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For potential applications in spintronics and quantum computing, it is desirable to place a quantum spin Hall insulator [i.e., a 2D topological insulator (TI)] on a substrate while maintaining a large energy gap. Here, we demonstrate a unique approach to create the large-gap 2D TI state on a semiconductor surface, based on first-principles calculations and effective Hamiltonian analysis. We show that when heavy elements with strong spin orbit coupling (SOC) such as Bi and Pb atoms are deposited on a patterned H-Si(111) surface into a hexagonal lattice, they exhibit a 2D TI state with a large energy gap of ?0.5?eV. The TI state arises from an intriguing substrate orbital filtering effect that selects a suitable orbital composition around the Fermi level, so that the system can be matched onto a four-band effective model Hamiltonian. Furthermore, it is found that within this model, the SOC gap does not increase monotonically with the increasing strength of SOC. These interesting results may shed new light in future design and fabrication of large-gap topological quantum states.
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Glutaminase 2 negatively regulates the PI3K/AKT signaling and shows tumor suppression activity in human hepatocellular carcinoma.
Oncotarget
PUBLISHED: 05-07-2014
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The tumor suppressor p53 and its signaling pathway play a critical role in tumor prevention. As a direct p53 target gene, the role of glutaminase 2 (GLS2) in tumorigenesis is unclear. In this study, we found that GLS2 expression is significantly decreased in majority of human hepatocellular carcinoma (HCC). Restoration of GLS2 expression in HCC cells inhibits the anchorage-independent growth of cells and reduces the growth of HCC xenograft tumors. Interestingly, we found that GLS2 negatively regulates the PI3K/AKT signaling, which is frequently activated in HCC. Blocking the PI3K/AKT signaling in HCC cells largely abolishes the inhibitory effect of GLS2 on the anchorage-independent cell growth and xenograft tumor growth. The GLS2 promoter is hypermethylated in majority of HCC samples. CpG methylation of GLS2 promoter inhibits GLS2 transcription, whereas reducing the methylation of GLS2 promoter induces GLS2 expression. Taken together, our results demonstrate that GLS2 plays an important role in tumor suppression in HCC, and the negative regulation of PI3K/AKT signaling contributes greatly to this function of GLS2. Furthermore, hypermethylation of GLS2 promoter is an important mechanism contributing to the decreased GLS2 expression in HCC.
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Whole exome sequencing identifies a novel EMD mutation in a Chinese family with dilated cardiomyopathy.
BMC Med. Genet.
PUBLISHED: 04-21-2014
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Variants in the emerin gene (EMD) were implicated in X-linked recessive Emery-Dreifuss muscular dystrophy (EDMD), characterized by early-onset contractures of tendons, progressive muscular weakness and cardiomyopathy. To date, 223 mutations have been reported in EMD gene and the majority of them caused a predominant skeletal muscular phenotype. In this study, we identified a novel deletion mutation in EMD exon 1, which results in almost a complete loss of emerin protein in a large Chinese family. However, the patients suffered severe dilated cardiomyopathy (DCM) but very mild skeletal muscle disorder.
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USP22 promotes the G1/S phase transition by upregulating FoxM1 expression via ?-catenin nuclear localization and is associated with poor prognosis in stage II pancreatic ductal adenocarcinoma.
Int. J. Oncol.
PUBLISHED: 04-04-2014
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Ubiquitin-specific protease 22 (USP22), a newly discovered member of ubiquitin hydrolase family, exhibits a critical function in cell cycle progression and tumorigenesis. The forkhead box M1 (FoxM1) transcription factor plays a crucial role in cell proliferation, differentiation and transformation. However, the expression and functions of USP22 in pancreatic ductal adenocarcinoma (PDA) and whether FoxM1 is involved in USP22-mediated cell cycle regulation have not been studied. We examined the expression of USP22 and FoxM1 in 136 stage II PDA tissues by immunohistochemistry. Clinical significance was analyzed by multivariate Cox regression analysis, Kaplan-Meier curves and log-rank test. RT-PCR, western blot analysis, luciferase and immunofluorescence assays were used to investigate the molecular function of USP22 and FoxM1 in PDA fresh tissues and cell lines. USP22 and FoxM1 were significantly upregulated in PDA tissues compared with the paired normal carcinoma-adjacent tissues. A statistical correlation was observed between USP22 and FoxM1 expression. The expression of USP/FoxM1 and co-expression of both factors correlated with tumor size, lymph node metastasis and overall survival. Multivariate Cox regression analysis revealed that the expression of USP22/FoxM1, especially the co-expression of both factors, is an independent, unfavorable prognostic factor. USP22 overexpression is accompanied by an increase in FoxM1 expression and USP22 increases FoxM1 expression to promote G1/S transition and cell proliferation through promoting ?-catenin nuclear translocation in PDA cell lines. USP22 promotes the G1/S phase transition by upregulating FoxM1 expression via promoting ?-catenin nuclear localization. USP22 and FoxM1 may act as prognostic markers and potential targets for PDA.
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Loss of the lac Operon Contributes to Salmonella Invasion of Epithelial Cells Through Derepression of Flagellar Synthesis.
Curr. Microbiol.
PUBLISHED: 03-30-2014
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Salmonella, a genus that is closely related to Escherichia coli, includes many pathogens of humans and other animals. A notable feature that distinguishes Salmonella from E. coli is lactose negativity, because the lac operon is lost in most Salmonella genomes. Here, we expressed the lac operon in Salmonella enterica serovar Typhimurium and compared the virulence of the Lac(+) strain to that of the wild-type strain in a murine model, invasion assays, and macrophage replication assays. We showed that the Lac(+) strain is attenuated in vivo and the attenuation of virulence is caused by its defect in epithelial cell invasion. However, the invasion-defective phenotype is unrelated to lactose utilization. Through sequencing and the comparison of the transcriptome profile between the Lac(+) and wild-type strains during invasion, we found that most flagellar genes were markedly downregulated in the Lac(+) strain, while other genes associated with invasion, such as the majority of genes encoded in Salmonella pathogenicity island 1, were not differentially expressed. Moreover, we discovered that lacA is the major repressor of flagellar gene expression in the lac operon. In conclusion, these data demonstrate that the lac operon decreases Salmonella invasion of epithelial cells through repression of flagellar biosynthesis. As the ability to invade epithelial cells is a critical virulence determinant of Salmonella, our results provide important evidence that the loss of the lac operon contributes to the evolution of Salmonella pathogenicity.
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Clinical characteristics and prognostic analysis of triple-negative breast cancer patients.
Mol Clin Oncol
PUBLISHED: 03-21-2014
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It is well-established that triple-negative breast cancer (TNBC) is a subtype of breast cancer, characterized by a poor prognosis and aggressive biological behavior. However, the available relevant data on TNBC in non-Western populations are limited. In order to analyze the clinicopathological and molecular biological characteristics and observe survival and prognostic factors, 972 breast cancer patients (156 of whom had TNBC) who received treatment at the First Affiliated Hospital of Medical School of Xi'an Jiaotong University and the First Hospital of China Medical University, between January, 2004 and January, 2007 were retrospectively evaluated. In the univariate analysis, tumor size, TNM stage, axillary lymph node status and recurrence or metastasis were identified as prognostic factors for 7-year disease-free survival (DFS) and overall survival (OS). Our multivariate Cox's regression analysis demonstrated that tumor size and axillary lymph node status were significant prognostic factors for 7-year DFS and OS. Notably, tumor subgroup (TNBC vs. non-TNBC) was a significant prognostic factor associated with 7-year DFS and OS in breast cancer. It was suggested that TNBC exhibited a worse 7-year survival compared with that in non-TNBC patients, most likely due to its more aggressive behavior and insensitivity to specific therapy.
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Quantitative determination and validation of avermectin B1a in commercial products using quantitative nuclear magnetic resonance spectroscopy.
Magn Reson Chem
PUBLISHED: 03-14-2014
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Nuclear magnetic resonance is defined as a quantitative spectroscopic tool that enables a precise determination of the number of substances in liquids as well as in solids. There is few report demonstrating the application of NMR in the quantification of avermectin B1a (AVB1a ); here, a proton nuclear magnetic resonance spectroscopy ((1) H NMR) using benzene [1-methoxy-4-(2-nitroethyl) (PMN)] as an internal standard and deuterochloroform as an NMR solvent was tested for the quantitative determination of AVB1a . The integrated signal of AVB1a at 5.56?ppm and the signal of PMN at 8.14?ppm in the (1) H NMR spectrum were used for quantification purposes. Parameters of specificity, linearity, accuracy, precision, intermediate precision, range, limit of detection (LOD), limit of quantification (LOQ), stability and robustness were validated. The established method was accurate and precise with good recovery (98.86%) and relative standard deviation (RSD) of assay (0.34%) within the linearity of the calibration curve ranging from 5.08 to 13.58?mg/ml (R(2) ?=?0.9999). The LOD and LOQ were 0.009 and 0.029?mg/ml, which indicated the excellent sensitivity of the method. The stability of the method was testified by a calculated RSD of 0.11%. The robustness was testified by modification of four different parameters, and the differences among each parameter were all less than 0.1%. Comparing with the assay described by the manufacturer of avermectin tablets, there was no significant difference between the assay obtained by HPLC and quantitative NMR (qNMR), which indicated qNMR was a simple and efficient method for the determination of AVB1a in commercial formulation products.
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Hepatitis B virus X protein promotes hepatocellular carcinoma transformation through interleukin-6 activation of microRNA-21 expression.
Eur. J. Cancer
PUBLISHED: 03-06-2014
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Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide, and chronic hepatitis B virus (HBV) infection is the major risk factor of HCC. The virus encodes HBV X (HBx) protein that plays a critical role in the development of HCC. Studies have revealed numerous HBx-altered genes and signalling pathways that heavily contribute to tumourigenesis of non-tumour hepatocytes. However, the role of HBx in regulating other critical gene regulators such as microRNAs is poorly understood, which impedes the exploration of a complete HBx-associated carcinogenic network. Besides, critical microRNAs that drive the transformation of non-tumour hepatocytes are yet to be identified. Here, we overexpressed C-terminal truncated HBx protein in a non-tumour hepatocyte cell line MIHA, and measured a panel of cancer-associated miRNAs. We observed that oncogenic miR-21 was upregulated upon ectopic expression of this viral protein variant. HBx-miR-21 pathway was prevalent in HCC cells as inhibition of HBx in Hep3B and PLC/PRF/5 cells significantly suppressed miR-21 expression. Subsequently, we showed that the upregulation of miR-21 was mediated by HBx-induced interleukin-6 pathway followed by activation of STAT3 transcriptional factor. The high dependency of miR-21 expression to HBx protein suggested a unique viral oncogenic pathway that could aberrantly affect a network of gene expression. Importantly, miR-21 was essential in the HBx-induced transformation of non-tumour hepatocytes. Inhibition of miR-21 effectively attenuated anchorage-independent colony formation and subcutaneous tumour growth of MIHA cells. Our study suggested that overexpression of miR-21 was critical to promote early carcinogenesis of hepatocytes upon HBV infection.
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Neural Trade-Offs between Recognizing and Categorizing Own- and Other-Race Faces.
Cereb. Cortex
PUBLISHED: 03-05-2014
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Behavioral research has suggested a trade-off relationship between individual recognition and race categorization of own- and other-race faces, which is an important behavioral marker of face processing expertise. However, little is known about the neural mechanisms underlying this trade-off. Using functional magnetic resonance imaging (fMRI) methodology, we concurrently asked participants to recognize and categorize own- and other-race faces to examine the neural correlates of this trade-off relationship. We found that for other-race faces, the fusiform face area (FFA) and occipital face area (OFA) responded more to recognition than categorization, whereas for own-race faces, the responses were equal for the 2 tasks. The right superior temporal sulcus (STS) responses were the opposite to those of the FFA and OFA. Further, recognition enhanced the functional connectivity from the right FFA to the right STS, whereas categorization enhanced the functional connectivity from the right OFA to the right STS. The modulatory effects of these 2 couplings were negatively correlated. Our findings suggested that within the core face processing network, although recognizing and categorizing own- and other-race faces activated the same neural substrates, there existed neural trade-offs whereby their activations and functional connectivities were modulated by face race type and task demand due to one's differential processing expertise with own- and other-race faces.
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Red yeast rice repairs kidney damage and reduces inflammatory transcription factors in rat models of hyperlipidemia.
Exp Ther Med
PUBLISHED: 03-04-2014
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Xuezhikang (XZK), an extract of red yeast rice, has been widely used for the management of hyperlipidemia and coronary heart disease (CHD); however, the effects of XZK treatment on kidney injury have not yet been fully identified. The aim of the current study was to evaluate the effects of XZK on the kidneys and investigate the related mechanisms in a rat model of hyperlipidemia. Thus, the effect on inflammatory transcription factors and kidney damage was investigated with in vitro and in vivo experiments on hyperlipidemic rats following XZK treatment. The results revealed that the plasma levels of total cholesterol (TC), triglycerides (TG) and low-density lipoprotein-cholesterol (LDL-C) were significantly decreased, while the levels of high-density lipoprotein-cholesterol (HDL-C) were significantly upregulated in the XZK treatment group, as compared with those in the hyperlipidemia group (P<0.05). In addition, the results demonstrated that XZK was able to repair the kidney damage caused by hyperlipidemia. Furthermore, the expression levels of the inflammatory transcription factors, tumor necrosis factor-? and interleukin-6, were shown to be reduced in the XZK group when compared with the hyperlipidemia group. In summary, XZK reduces kidney injury, downregulates the levels of TG, TC and LDL-C, as well as the expression levels of inflammatory transcription factors, and upregulates HDL-C. These results further the understanding of the molecular pathogenic mechanisms underlying hyperlipidemia and aid the development of XZK as an effective therapeutic agent for hyperlipidemia.
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LIF promotes tumorigenesis and metastasis of breast cancer through the AKT-mTOR pathway.
Oncotarget
PUBLISHED: 02-21-2014
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Leukemia inhibitory factor (LIF) is a multi-functional cytokine protein. The role of LIF in tumorigenesis is not well-understood. Here, we found that LIF promotes tumorigenesis and metastasis of breast cancer. LIF promotes cell proliferation and anchorage-independent growth of breast cancer cells in vitro, and the growth of xenograft breast tumors in vivo. LIF also promotes invasion and migration of breast cancer cells in vitro and metastasis of breast cancer in vivo. We found that LIF activates the AKT-mTOR signaling pathway to promote tumorigenesis and metastasis of breast cancer. Inhibiting the AKT activity can largely block the activation of the mTOR pathway by LIF, suggesting that LIF activates the mTOR pathway through AKT. Inhibiting the AKT activity as well as inhibiting the mTOR activity largely block the promoting effect of LIF on tumorigenesis and metastasis. Furthermore, overexpression of LIF is significantly associated with a poorer relapse free survival in breast cancer patients. Taken together, our data strongly suggest that LIF plays an important role in the tumorigenesis and metastasis of breast cancer, and could be an important prognostic marker for breast cancer.
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Improved site-specific recombinase-based method to produce selectable marker- and vector-backbone-free transgenic cells.
Sci Rep
PUBLISHED: 02-06-2014
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PhiC31 integrase-mediated gene delivery has been extensively used in gene therapy and animal transgenesis. However, random integration events are observed in phiC31-mediated integration in different types of mammalian cells; as a result, the efficiencies of pseudo attP site integration and evaluation of site-specific integration are compromised. To improve this system, we used an attB-TK fusion gene as a negative selection marker, thereby eliminating random integration during phiC31-mediated transfection. We also excised the selection system and plasmid bacterial backbone by using two other site-specific recombinases, Cre and Dre. Thus, we generated clean transgenic bovine fetal fibroblast cells free of selectable marker and plasmid bacterial backbone. These clean cells were used as donor nuclei for somatic cell nuclear transfer (SCNT), indicating a similar developmental competence of SCNT embryos to that of non-transgenic cells. Therefore, the present gene delivery system facilitated the development of gene therapy and agricultural biotechnology.
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Seeing Jesus in toast: neural and behavioral correlates of face pareidolia.
Cortex
PUBLISHED: 01-21-2014
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Face pareidolia is the illusory perception of non-existent faces. The present study, for the first time, contrasted behavioral and neural responses of face pareidolia with those of letter pareidolia to explore face-specific behavioral and neural responses during illusory face processing. Participants were shown pure-noise images but were led to believe that 50% of them contained either faces or letters; they reported seeing faces or letters illusorily 34% and 38% of the time, respectively. The right fusiform face area (rFFA) showed a specific response when participants "saw" faces as opposed to letters in the pure-noise images. Behavioral responses during face pareidolia produced a classification image (CI) that resembled a face, whereas those during letter pareidolia produced a CI that was letter-like. Further, the extent to which such behavioral CIs resembled faces was directly related to the level of face-specific activations in the rFFA. This finding suggests that the rFFA plays a specific role not only in processing of real faces but also in illusory face perception, perhaps serving to facilitate the interaction between bottom-up information from the primary visual cortex and top-down signals from the prefrontal cortex (PFC). Whole brain analyses revealed a network specialized in face pareidolia, including both the frontal and occipitotemporal regions. Our findings suggest that human face processing has a strong top-down component whereby sensory input with even the slightest suggestion of a face can result in the interpretation of a face.
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Exploration of novel cellular and serological antigen biomarkers in the ORFeome of Mycobacterium tuberculosis.
Mol. Cell Proteomics
PUBLISHED: 01-21-2014
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Increasing evidence demonstrates that antigen-specific cellular and humoral immunity plays an indispensable role in protection against Mycobacterium tuberculosis infection. Antigen is a key element in the development of a successful diagnostic method and vaccine. However, few antigens are available, and a systemic study on M. tuberculosis ORFeome-based antigen screening is still lacking. In the current study, a genome-wide examination was conducted on high-throughput M. tuberculosis encoding proteins and novel antigens were identified via a comprehensive investigation of serological and antigen-specific cellular responses. The serological immunoglobulin G level of each protein was detected in pooled sera from 200 pulmonary tuberculosis patients by means of semi-quantitative Western blot. Of the 1,250 detected proteins, 29 were present at a higher level relative to the commercialized 38-kDa protein. Furthermore, the top 12 of the 29 proteins had not been previously reported, and their antigenicity was validated in serum from each individual patient. Results confirmed that the 12 proteins displayed nearly identical immunoglobulin G antibody levels in patients with pulmonary and extrapulmonary tuberculosis. Antigen-specific cellular interferon-? secretion was also evaluated using a cell-based ELISPOT assay. Thirty-four of the proteins were able to induce positive interferon-? production by peripheral blood mononuclear cells from pulmonary tuberculosis patients as judged by positive (commercial ESAT-6 antigen) and negative controls. The top 4 candidates out of the 34 proteins displayed good accuracy ranging from 50% to 80% compared with the commercial ESAT-6 antigen. Subsequent epitope examination confirmed that a pool of peptides, including a 25aa peptide from Rv1198, demonstrated significant tuberculosis-specific cellular interferon-? production. Overall, the current study draws significant attention to novel M. tuberculosis antigens, many of which have not been previously reported. This discovery provides a large amount of useful information for the diagnosis of tuberculosis and the development of vaccines to provide protection against tuberculosis.
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Myocardial Injury after Surgery Is a Risk Factor for Weaning Failure from Mechanical Ventilation in Critical Patients Undergoing Major Abdominal Surgery.
PLoS ONE
PUBLISHED: 01-01-2014
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Myocardial injury after noncardiac surgery (MINS) is a newly proposed concept that is common among adults undergoing noncardiac surgery and associated with substantial mortality. We analyzed whether MINS was a risk factor for weaning failure in critical patients who underwent major abdominal surgery.
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Human RAD6 Promotes G1-S Transition and Cell Proliferation through Upregulation of Cyclin D1 Expression.
PLoS ONE
PUBLISHED: 01-01-2014
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Protein ubiquitinylation regulates protein stability and activity. RAD6, an E2 ubiquitin-conjugating enzyme, which that has been substantially biochemically characterized, functions in a number of biologically relevant pathways, including cell cycle progression. In this study, we show that RAD6 promotes the G1-S transition and cell proliferation by regulating the expression of cyclin D1 (CCND1) in human cells. Furthermore, our data indicate that RAD6 influences the transcription of CCND1 by increasing monoubiquitinylation of histone H2B and trimethylation of H3K4 in the CCND1 promoter region. Our study presents, for the first time, an evidence for the function of RAD6 in cell cycle progression and cell proliferation in human cells, raising the possibility that RAD6 could be a new target for molecular diagnosis and prognosis in cancer therapeutics.
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Light Spatial Distribution in the Canopy and Crop Development in Cotton.
PLoS ONE
PUBLISHED: 01-01-2014
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The partitioning of light is very difficult to assess, especially in discontinuous or irregular canopies. The aim of the present study was to analyze the spatial distribution of photosynthetically active radiation (PAR) in a heterogeneous cotton canopy based on a geo-statistical sampling method. Field experiments were conducted in 2011 and 2012 in Anyang, Henan, China. Field plots were arranged in a randomized block design with the main plot factor representing the plant density. There were 3 replications and 6 densities used in every replicate. The six plant density treatments were 15,000, 33,000, 51,000, 69,000, 87,000 and 105,000 plants ha-1. The following results were observed: 1) transmission within the canopy decreased with increasing density and significantly decreased from the top to the bottom of the canopy, but the greatest decreases were observed in the middle layers of the canopy on the vertical axis and closing to the rows along the horizontal axis; 2) the transmitted PAR (TPAR) of 6 different cotton populations decreased slowly and then increased slightly as the leaves matured, the TPAR values were approximately 52.6-84.9% (2011) and 42.7-78.8% (2012) during the early cotton developmental stage, and were 33.9-60.0% (2011) and 34.5-61.8% (2012) during the flowering stage; 3) the Leaf area index (LAI) was highly significant exponentially correlated (R2?=?0.90 in 2011, R2?=?0.91 in 2012) with the intercepted PAR (IPAR) within the canopy; 4) and a highly significant linear correlation (R2?=?0.92 in 2011, R2?=?0.96 in 2012) was observed between the accumulated IPAR and the biomass. Our findings will aid researchers to improve radiation-use efficiency by optimizing the ideotype for cotton canopy architecture based on light spatial distribution characteristics.
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CXCR6 deficiency attenuates pressure overload-induced monocytes migration and cardiac fibrosis through downregulating TNF-?-dependent MMP9 pathway.
Int J Clin Exp Pathol
PUBLISHED: 01-01-2014
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An immerging role of TNF-? in collagen synthesis and cardiac fibrosis implies the significance of TNF-? production in the development of myocardial remodeling. Our previous study showed a reduction of TNF-? and attenuated cardiac remodeling in CXCR6 knockout (KO) mice after ischemia/reperfusion injury. However, the potential mechanism of TNF-?-mediated cardiac fibrosis with pressure overload has not been well elucidated. In the present study, we aim to investigate the role of CXCR6 in TNF-? release and myocardial remodeling in response to pressure overload. Pressure overload was performed by constriction of transverse aorta (TAC) surgery on CXCR6 KO mice and C57 wild-type (WT) counterparts. At 6 weeks after TAC, cardiac remodeling was assessed by echocardiography, cardiac TNF-? release and its type I receptor (TNFRI), were detected by ELISA and western blot, collagen genes Col1a1 (type I) and Col3a1 (type III) were examined by real-time PCR. Compared with CXCR6 WT mice, CXCR6 KO mice exhibited less cardiac dysfunction, reduced expression of TNFRI, Col1a1 and Col3a. In vitro, we confirmed that CXCR6 deficiency led to reduced homing and infiltration of CD11b(+) monocytes, which contributed to attenuated TNF-? release in myocardium. Furthermore, TNFRI antagonist pretreatment blocked AT1 receptor signaling and NOX4 expression, reduced collagen synthesis, and blunted the activity of MMP9 in CXCR6 WT mice after TAC, but these were not observed in CXCR6 KO mice. In the present work, we propose a mechanism that CXCR6 is essential for pressure overload-mediated myocardial recruitment of monocytes, which contributes to cardiac fibrosis through TNF-?-dependent MMP9 activation and collagen synthesis.
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Generation of mastitis resistance in cows by targeting human lysozyme gene to ?-casein locus using zinc-finger nucleases.
Proc. Biol. Sci.
PUBLISHED: 01-01-2014
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Mastitis costs the dairy industry billions of dollars annually and is the most consequential disease of dairy cattle. Transgenic cows secreting an antimicrobial peptide demonstrated resistance to mastitis. The combination of somatic cell gene targeting and nuclear transfer provides a powerful method to produce transgenic animals. Recent studies found that a precisely placed double-strand break induced by engineered zinc-finger nucleases (ZFNs) stimulated the integration of exogenous DNA stretches into a pre-determined genomic location, resulting in high-efficiency site-specific gene addition. Here, we used ZFNs to target human lysozyme (hLYZ) gene to bovine ?-casein locus, resulting in hLYZ knock-in of approximately 1% of ZFN-treated bovine fetal fibroblasts (BFFs). Gene-targeted fibroblast cell clones were screened by junction PCR amplification and Southern blot analysis. Gene-targeted BFFs were used in somatic cell nuclear transfer. In vitro assays demonstrated that the milk secreted by transgenic cows had the ability to kill Staphylococcus aureus. We report the production of cloned cows carrying human lysozyme gene knock-in ?-casein locus using ZFNs. Our findings open a unique avenue for the creation of transgenic cows from genetic engineering by providing a viable tool for enhancing resistance to disease and improving the health and welfare of livestock.
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The application of quantitative NMR for the facile, rapid and reliable determination of clindamycin phosphate in a conventional tablet formulation.
Magn Reson Chem
PUBLISHED: 01-01-2014
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Spectroscopic tools such as NMR can be applied to the quantitative analysis of active pharmaceutical ingredients with relative ease and accuracy. Here, we demonstrate the quantification of clindamycin phosphate (CLP) in a conventional tablet formulation, performed using potassium hydrogen phthalate (KHP) as the internal standard and deuterium oxide (D2O) as the NMR solvent. The methyl protons signal of CLP at 0.72 ppm (triplet) relative to the signal of KHP at 7.37-7.40 ppm (multiplet) was used for quantification purposes using (1)H NMR. This method was shown to be specific and linear (r = 0.9997) within the CLP concentration range from 7.2 to 23.1 mg per 0.5 ml of D2O. The maximum relative standard deviation (RSD) of accuracy and precision was calculated at 0.39% and 0.64%, respectively. The limits of detection (LOD) and quantification were 0.04 and 0.11 mg/ml, respectively. The method was highly stable with a calculated RSD of 0.03%. The robustness of the method was demonstrated by changing four different parameters, and the difference among each parameter was ? 0.78%. The findings of this work were in good agreement with previously reported conventional HPLC-based approaches, highlighting its applicability in the determination of other active pharmaceutical ingredients in conventional formulations for quality control purposes.
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Tumor suppressor p53 and its gain-of-function mutants in cancer.
Acta Biochim. Biophys. Sin. (Shanghai)
PUBLISHED: 12-29-2013
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Tumor suppressor p53 plays a pivotal role in tumor suppression. p53 is the most frequently mutated gene in cancer. As a transcription factor, p53 mainly exerts its role in tumor suppression through transcriptional regulation of its downstream target genes. Thus, p53 and its target genes form a complex p53 signaling pathway to regulate a wide variety of biological processes to prevent tumorigenesis. Recent studies have revealed that in addition to apoptosis, cell cycle arrest and senescence, p53s functions in the regulation of energy metabolism and anti-oxidant defense contribute significantly to its role in tumor suppression. Studies further show that many tumor-associated mutant p53 proteins not only lose tumor suppressive functions of wild-type p53, but also gain new oncogenic activities that are independent of wild-type p53, including promoting tumor cell proliferation, survival, metabolic changes, angiogenesis, and metastasis, which are defined as mutant p53 gain-of-function. The frequent loss of wild-type p53 function and the gain-of-function of mutant p53 in human tumors make p53 an extremely attractive target for cancer therapy. Different strategies and many small-molecule drugs are being developed for the p53-based tumor therapy. Here, we review the mechanisms of p53 in tumor suppression and gain-of-function mutant p53 in tumor development, as well as the recent advances in the development of the p53-based tumor therapy.
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Tumor suppressor p53 and its mutants in cancer metabolism.
Cancer Lett.
PUBLISHED: 11-21-2013
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Tumor-suppressor p53 plays a key role in tumor prevention. As a transcription factor, p53 transcriptionally regulates its target genes to regulate different biological processes in response to stress, including apoptosis, cell cycle arrest or senescence, to exert its function in tumor suppression. Recent studies have revealed that metabolic regulation is a novel function of p53. Metabolic changes have been regarded as a hallmark of tumors and a key contributor to tumor development. p53 regulates many different aspects of metabolism, including glycolysis, mitochondrial oxidative phosphorylation, pentose phosphate pathway, fatty acid synthesis and oxidation, to maintain the homeostasis of cellular metabolism, which contributes to the role of p53 in tumor suppression. p53 is frequently mutated in human tumors. In addition to loss of tumor suppressive function, tumor-associated mutant p53 proteins often gain new tumorigenic activities, termed gain-of-function of mutant p53. Recent studies have shown that mutant p53 mediates metabolic changes in tumors as a novel gain-of-function to promote tumor development. Here we review the functions and mechanisms of wild-type and mutant p53 in metabolic regulation, and discuss their potential roles in tumorigenesis.
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[Diagnosis and surgical treatment of parathyroid neoplasms].
Zhonghua Yi Xue Za Zhi
PUBLISHED: 10-31-2013
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To explore the clinical features, diagnosis and surgical treatment of parathyroid neoplasms.
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Genomic diversity and adaptation of Salmonella enterica serovar Typhimurium from analysis of six genomes of different phage types.
BMC Genomics
PUBLISHED: 10-11-2013
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Salmonella enterica serovar Typhimurium (or simply Typhimurium) is the most common serovar in both human infections and farm animals in Australia and many other countries. Typhimurium is a broad host range serovar but has also evolved into host-adapted variants (ie. isolated from a particular host such as pigeons). Six Typhimurium strains of different phage types (defined by patterns of susceptibility to lysis by a set of bacteriophages) were analysed using Illumina high-throughput genome sequencing.
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Transgenic 6F tomatoes act on the small intestine to prevent systemic inflammation and dyslipidemia caused by Western diet and intestinally derived lysophosphatidic acid.
J. Lipid Res.
PUBLISHED: 10-01-2013
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We recently reported that levels of unsaturated lysophosphatidic acid (LPA) in the small intestine significantly correlated with the extent of aortic atherosclerosis in LDL receptor-null (LDLR?/?) mice fed a Western diet (WD). Here we demonstrate that WD increases unsaturated (but not saturated) LPA levels in the small intestine of LDLR?/? mice and causes changes in small intestine gene expression. Confirmation of microarray analysis by quantitative RT-PCR showed that adding transgenic tomatoes expressing the apoA-I mimetic peptide 6F (Tg6F) to WD prevented many WD-mediated small intestine changes in gene expression. If instead of feeding WD, unsaturated LPA was added to chow and fed to the mice: i) levels of LPA in the small intestine were similar to those induced by feeding WD; ii) gene expression changes in the small intestine mimicked WD-mediated changes; and iii) changes in plasma serum amyloid A, total cholesterol, triglycerides, HDL-cholesterol levels, and the fast-performance liquid chromatography lipoprotein profile mimicked WD-mediated changes. Adding Tg6F (but not control tomatoes) to LPA-supplemented chow prevented the LPA-induced changes. We conclude that: i) WD-mediated systemic inflammation and dyslipidemia may be in part due to WD-induced increases in small intestine LPA levels; and ii) Tg6F reduces WD-mediated systemic inflammation and dyslipidemia by preventing WD-induced increases in LPA levels in the small intestine.
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[Clinical observation of supracricoid partial laryngectomy].
Zhonghua Er Bi Yan Hou Tou Jing Wai Ke Za Zhi
PUBLISHED: 09-11-2013
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To evaluate clinical outcomes and pronouncing and swallowing functions after supracricoid partial laryngectomy (SCPL).
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Thermogravimetric analysis of lignocellulosic biomass with ionic liquid pretreatment.
Bioresour. Technol.
PUBLISHED: 09-05-2013
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Thermogravimetry (TG) was employed to understand the interactions between ionic liquids (ILs) and biomass components. The thermal decomposition profiles of several biomass samples with IL pretreatment at different temperatures were studied by TG. Samples of Avicel (PH101), xylan from beechwood and alkaline lignin as well as switchgrass and corn stover were pretreated using 1-butyl-3-methylimidazolium acetate ([C4mim][OAc]) at temperatures of 50-130°C for 6h. Analysis of TG data provided insight into the mode of degradation of xylan and lignin in [C4mim][OAc]. Pretreated Avicel samples exhibited higher decomposition temperatures due to transformation from cellulose I into cellulose II, while samples of switchgrass and corn stover showed an improved thermal stability as a result of removal of minerals by [C4mim][OAc]. More intensive pretreatment produced decreased thermal resistance due to degradation of biomass components and decrystallization.
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Development of a DNA microarray method for detection and identification of all 15 distinct O-antigen forms of Legionella pneumophila.
Appl. Environ. Microbiol.
PUBLISHED: 08-23-2013
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Legionella is ubiquitous in many environments. At least 50 species and 70 serogroups of the Gram-negative bacterium have been identified. Of the 50 species, 20 are pathogenic, and Legionella pneumophila is responsible for the great majority (approximately 90%) of the Legionnaires disease cases that occur. Furthermore, of the 15 L. pneumophila serogroups identified, O1 alone causes more than 84% of the Legionnaires disease cases that occur worldwide. Rapid and reliable assays for the detection and identification of L. pneumophila in water, environmental, and clinical samples are in great demand. L. pneumophila bacteria are traditionally identified by their O antigens by immunological methods. We have recently developed an O serogroup-specific DNA microarray for the detection of all 15 distinct O-antigen forms of L. pneumophila, including serogroups O1 to O15. A total of 35 strains were used to verify the specificity of the microarray, including 15 L. pneumophila O-antigen standard reference strains and seven L. pneumophila clinical isolates as target strains, seven reference strains of other non-pneumophila Legionella species as closely related strains, and six non-Legionella bacterial species as nonrelated strains. The detection sensitivity was 1 ng of genomic DNA or 0.4 CFU/ml in water samples with filter enrichment and plate culturing. This study demonstrated that the microarray allows specific, sensitive, and reproducible detection of L. pneumophila serogroups. To the best of our knowledge, this is the first report of a microarray serotyping method for all 15 distinct O-antigen forms of L. pneumophila.
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Spliced MDM2 isoforms promote mutant p53 accumulation and gain-of-function in tumorigenesis.
Nat Commun
PUBLISHED: 08-20-2013
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The tumour suppressor p53 is frequently mutated in tumours. Mutant p53 (Mutp53) proteins often gain new activities in promoting tumorigenesis, defined as gain-of-function (GOF). Mutp53 can accumulate to high levels in tumours, which promotes mutp53 GOF in tumorigenesis. The mechanism of mutp53 accumulation is poorly understood. Here we find that MDM2 isoforms promote mutp53 accumulation in tumours. MDM2 isoform B (MDM2-B), the MDM2 isoform most frequently over-expressed in human tumours, interacts with full-length MDM2 to inhibit MDM2-mediated mutp53 degradation, promoting mutp53 accumulation and GOF in tumorigenesis. Furthermore, MDM2-B overexpression correlates with mutp53 accumulation in human tumours. In mutp53 knock-in mice, a MDM2 isoform similar to human MDM2-B is overexpressed in the majority of tumours, which promotes mutp53 accumulation and tumorigenesis. Thus, overexpression of MDM2 isoforms promotes mutp53 accumulation in tumours, contributing to mutp53 GOF in tumorigenesis. This may be an important mechanism by which MDM2 isoforms promote tumorigenesis.
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Tumour-associated mutant p53 drives the Warburg effect.
Nat Commun
PUBLISHED: 06-21-2013
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Tumour cells primarily utilize aerobic glycolysis for energy production, a phenomenon known as the Warburg effect. Its mechanism is not well understood. The tumour suppressor gene p53 is frequently mutated in tumours. Many tumour-associated mutant p53 (mutp53) proteins not only lose tumour suppressive function but also gain new oncogenic functions that are independent of wild-type p53, defined as mutp53 gain of function (GOF). Here we show that tumour-associated mutp53 stimulates the Warburg effect in cultured cells and mutp53 knockin mice as a new mutp53 GOF. Mutp53 stimulates the Warburg effect through promoting GLUT1 translocation to the plasma membrane, which is mediated by activated RhoA and its downstream effector ROCK. Inhibition of RhoA/ROCK/GLUT1 signalling largely abolishes mutp53 GOF in stimulating the Warburg effect. Furthermore, inhibition of glycolysis in tumour cells greatly compromises mutp53 GOF in promoting tumorigenesis. Thus, our results reveal a new mutp53 GOF and a mechanism for controlling the Warburg effect.
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Lipopolysaccharide neutralization by a novel peptide derived from phosvitin.
Int. J. Biochem. Cell Biol.
PUBLISHED: 05-29-2013
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Lipopolysaccharide (LPS), also known as endotoxin, is the primary trigger of sepsis, which is associated with high mortality in patients. No therapeutic agents are currently efficacious enough to protect patients from sepsis characterized by LPS-mediated tissue damage and organ failure. Previously, a phosvitin-derived peptide, Pt5, which consists of the C-terminal 55 residues of zebrafish phosvitin, has been shown to function as an antibacterial agent. In this study, we have generated six mutants by site-directed mutagenesis based on the sequence of Pt5, and found that one of the six mutants, Pt5e, showed the strongest bactericidal activities against Escherichia coli and Staphylococcus aureus. We then demonstrated that Pt5e was able to bind to LPS and lipoteichoic acid (LTA). More importantly, we showed that Pt5e significantly inhibited LPS-induced tumor-necrosis factor (TNF)-? and interleukin (IL)-1? release from murine RAW264.7 cells and considerably reduced serum TNF-? and IL-1? levels in mice. Additionally, Pt5e protected the liver from damage by LPS, and remarkably promoted the survival rate of the endotoxemia mice. Furthermore, Pt5e displayed no cytotoxicity to murine RAW264.7 macrophages and no hemolytic activity toward human red blood cells. These data together indicate that Pt5e is an endotoxin-neutralizing agent with a therapeutic potential in clinical treatment of LPS-induced sepsis.
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Pretreatment with interleukin-33 reduces warm hepatic ischemia/reperfusion injury in mice.
Chin. Med. J.
PUBLISHED: 05-16-2013
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Interleukin (IL)-33 is a recently identified member of the IL-1 family that binds to the receptor, ST2L. This study examined IL-33 production in mouse liver and investigated its role in hepatic ischemia/reperfusion (I/R) injury.
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Structural diversity in Salmonella O antigens and its genetic basis.
FEMS Microbiol. Rev.
PUBLISHED: 05-15-2013
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This review covers the structures and genetics of the 46 O antigens of Salmonella, a major pathogen of humans and domestic animals. The variation in structures underpins the serological specificity of the 46 recognized serogroups. The O antigen is important for the full function and virulence of many bacteria, and the considerable diversity of O antigens can confer selective advantage. Salmonella O antigens can be divided into two major groups: those which have N-acetylglucosamine (GlcNAc) or N-acetylgalactosamine (GalNAc) and those which have galactose (Gal) as the first sugar in the O unit. In recent years, we have determined 21 chemical structures and sequenced 28 gene clusters for GlcNAc-/GalNAc-initiated O antigens, thus completing the structure and DNA sequence data for the 46 Salmonella O antigens. The structures and gene clusters of the GlcNAc-/GalNAc-initiated O antigens were found to be highly diverse, and 24 of them were found to be identical or closely related to Escherichia coli O antigens. Sequence comparisons indicate that all or most of the shared gene clusters were probably present in the common ancestor, although alternative explanations are also possible. In contrast, the better-known eight Gal-initiated O antigens are closely related both in structures and gene cluster sequences.
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Resting state neural networks for visual Chinese word processing in Chinese adults and children.
Neuropsychologia
PUBLISHED: 05-10-2013
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This study examined the resting state neural networks for visual Chinese word processing in Chinese children and adults. Both the functional connectivity (FC) and amplitude of low frequency fluctuation (ALFF) approaches were used to analyze the fMRI data collected when Chinese participants were not engaged in any specific explicit tasks. We correlated time series extracted from the visual word form area (VWFA) with those in other regions in the brain. We also performed ALFF analysis in the resting state FC networks. The FC results revealed that, regarding the functionally connected brain regions, there exist similar intrinsically organized resting state networks for visual Chinese word processing in adults and children, suggesting that such networks may already be functional after 3-4 years of informal exposure to reading plus 3-4 years formal schooling. The ALFF results revealed that children appear to recruit more neural resources than adults in generally reading-irrelevant brain regions. Differences between child and adult ALFF results suggest that childrens intrinsic word processing network during the resting state, though similar in functional connectivity, is still undergoing development. Further exposure to visual words and experience with reading are needed for children to develop a mature intrinsic network for word processing. The developmental course of the intrinsically organized word processing network may parallel that of the explicit word processing network.
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Structure and gene cluster of the O-antigen of Escherichia coli O154.
Carbohydr. Res.
PUBLISHED: 04-25-2013
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The O-polysaccharide (O-antigen) of Escherichia coli O154 was studied by sugar analysis along with 1D and 2D (1)H and (13)C NMR spectroscopy. The following structure of the branched pentasaccharide repeating unit was established: [structure: see text]. The O-antigen gene cluster of E. coli O154 was sequenced. The gene functions were tentatively assigned by comparison with sequences in the available databases and found to be in full agreement with the O-polysaccharide structure.
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p63 regulates glutaminase 2 expression.
Cell Cycle
PUBLISHED: 04-10-2013
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The transcription factor p63 is critical for many biological processes, including development and maintenance of epidermal tissues and tumorigenesis. Here, we report that the TAp63 isoforms regulate cell metabolism through the induction of the mitochondrial glutaminase 2 (GLS2) gene both in primary cells and tumor cell lines. By ChIP analysis and luciferase assay, we confirmed that TAp63 binds directly to the p53/p63 consensus DNA binding sequence within the GLS2 promoter region. Given the critical role of p63 in epidermal differentiation, we have investigated the regulation of GLS2 expression during this process. GLS2 and TAp63 expression increases during the in vitro differentiation of primary human keratinocytes, and depletion of GLS2 inhibits skin differentiation both at molecular and cellular levels. We found that GLS2 and TAp63 expression are concomitantly induced in cancer cells exposed to oxidative stresses. siRNA-mediated depletion of GLS2 sensitizes cells to ROS-induced apoptosis, suggesting that the TAp63/GLS2 axis can be functionally important as a cellular antioxidant pathway in the absence of p53. Accordingly, we found that GLS2 is upregulated in colon adenocarcinoma. Altogether, our findings demonstrate that GLS2 is a bona fide TAp63 target gene, and that the TAp63-dependent regulation of GLS2 is important for both physiological and pathological processes.
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Synthesis and structure-activity relationship of 8-substituted protoberberine derivatives as a novel class of antitubercular agents.
Chem Cent J
PUBLISHED: 04-01-2013
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The emergence of multi-drug resistant tuberculosis (MDR-TB) has heightened the need for new chemical classes and innovative strategies to tackle TB infections. It is urgent to discover new classes of molecules without cross-resistance with currently used antimycobacterial drugs.
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Development of a DNA microarray for molecular identification of all 46 Salmonella O serogroups.
Appl. Environ. Microbiol.
PUBLISHED: 03-22-2013
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Salmonella is a major cause of food-borne disease in many countries. Serotype determination of Salmonella is important for disease assessment, infection control, and epidemiological surveillance. In this study, a microarray system that targets the O antigen-specific genes was developed for simultaneously detecting and identifying all 46 Salmonella O serogroups. Of these, 40 serogroups can be confidently identified, and the remaining 6, in three pairs (serogroups O67 and B, E1 and E4, and A and D1), need to be further distinguished from each other using PCR methods or conventional serotyping methods. The microarray was shown to be highly specific when evaluated against 293 Salmonella strains, 186 Shigella strains, representative Escherichia coli strains, and 10 strains of other bacterial species. The assay correctly identified 288 (98%) of the Salmonella strains. The detection sensitivity was determined to be 50 ng genomic DNA per sample. By testing simulated samples in a tomato background, 2 to 8 CFU per gram inoculated could be detected after enrichment. This newly developed microarray assay is the first molecular protocol that can be used for the comprehensive detection and identification of all 46 Salmonella O serogroups. Compared to the traditional serogrouping method, the microarray provides a reliable, high-throughput, and sensitive approach that can be used for rapid identification of multiple Salmonella O serogroups simultaneously.
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Role of the phenylalanine-hydroxylating system in aromatic substance degradation and lipid metabolism in the oleaginous fungus Mortierella alpina.
Appl. Environ. Microbiol.
PUBLISHED: 03-15-2013
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Mortierella alpina is a filamentous fungus commonly found in soil that is able to produce lipids in the form of triacylglycerols that account for up to 50% of its dry weight. Analysis of the M. alpina genome suggests that there is a phenylalanine-hydroxylating system for the catabolism of phenylalanine, which has never been found in fungi before. We characterized the phenylalanine-hydroxylating system in M. alpina to explore its role in phenylalanine metabolism and its relationship to lipid biosynthesis. Significant changes were found in the profile of fatty acids in M. alpina grown on medium containing an inhibitor of the phenylalanine-hydroxylating system compared to M. alpina grown on medium without inhibitor. Genes encoding enzymes involved in the phenylalanine-hydroxylating system (phenylalanine hydroxylase [PAH], pterin-4?-carbinolamine dehydratase, and dihydropteridine reductase) were expressed heterologously in Escherichia coli, and the resulting proteins were purified to homogeneity. Their enzymatic activity was investigated by high-performance liquid chromatography (HPLC) or visible (Vis)-UV spectroscopy. Two functional PAH enzymes were observed, encoded by distinct gene copies. A novel role for tetrahydrobiopterin in fungi as a cofactor for PAH, which is similar to its function in higher life forms, is suggested. This study establishes a novel scheme for the fungal degradation of an aromatic substance (phenylalanine) and suggests that the phenylalanine-hydroxylating system is functionally significant in lipid metabolism.
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JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

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In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.