排序方式: 共有36条查询结果,搜索用时 31 毫秒
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Patrick M. Bales Emilija Miljkovic Renke Sarah L. May Yang Shen Daniel C. Nelson 《PloS one》2013,8(6)
In bacterial biofilms, high molecular weight, secreted exopolysaccharides can serve as a scaffold to which additional carbohydrates, proteins, lipids, and nucleic acids adhere, forming the matrix of the developing biofilm. Here we report methods to extract and purify high molecular weight (>15 kDa) exopolysaccharides from biofilms of eight human pathogens, including species of Staphylcococcus, Klebsiella, Acinetobacter, Pseudomonas, and a toxigenic strain of Escherichia coli O157:H7. Glycosyl composition analysis indicated a high total mannose content across all strains with P. aeruginosa and A. baumannii exopolysaccharides comprised of 80–90% mannose, K. pneumoniae and S. epidermidis strains containing 40–50% mannose, and E. coli with ∼10% mannose. Galactose and glucose were also present in all eight strains, usually as the second and third most abundant carbohydrates. N-acetyl-glucosamine and galacturonic acid were found in 6 of 8 strains, while arabinose, fucose, rhamnose, and xylose were found in 5 of 8 strains. For linkage analysis, 33 distinct residue-linkage combinations were detected with the most abundant being mannose-linked moieties, in line with the composition analysis. The exopolysaccharides of two P. aeruginosa strains analyzed were consistent with the Psl carbohydrate, but not Pel or alginate. The S. epidermidis strain had a composition rich in mannose and glucose, which is consistent with the previously described slime associated antigen (SAA) and the extracellular slime substance (ESS), respectively, but no polysaccharide intracellular adhesion (PIA) was detected. The high molecular weight exopolysaccharides from E. coli, K. pneumoniae, and A. baumannii appear to be novel, based on composition and/or ratio analysis of carbohydrates. 相似文献
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Renke Dai Suoping Zhai Xiaoxiong Wei Matthew R. Pincus Robert E. Vestal Fred K. Friedman 《Journal of Protein Chemistry》1998,17(7):643-650
Cytochrome P450 1A2 metabolizes a number of important drugs, procarcinogens, and endogenous compounds. Several flavones, a
class of phytochemicals consumed in the human diet, have been shown to differentially inhibit human P450 1A2-mediated methoxyresorufin
demethylase. A molecular model of this P450 was constructed in order to elucidate the molecular basis of the P450-flavone
interaction. Flavone and its 3,5,7-trihydroxy and 3,5,7-trimethoxy derivatives were docked into the active site to assess
their mode of binding. The site is hydrophobic and includes several residues that hydrogen bond with substituents on the flavone
nucleus. The binding interactions of these flavones in the modeled active side are consistent with their relative inhibitory
potentials, namely 3,5,7-trihydroxylflavone > flavone >3,5,7-trimethoxylflavone, toward P450 1A2-mediated methoxyresorufin
demethylation. 相似文献
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Xuetao Sun Abdul Momen Jun Wu Hossein Noyan Renke Li Rüdiger von Harsdorf Mansoor Husain 《The Journal of biological chemistry》2014,289(24):16924-16935
p27Kip1 (p27), a key regulator of cell division, has been implicated in autophagy of cancer cells. However, its role in autophagy, the evolutionarily conserved catabolic process that enables cells to remove unwanted proteins and damaged organelles, had not been examined in the heart. Here we report that ectopic delivery of a p27 fusion protein (TAT-p27) was sufficient to induce autophagy in neonatal rat ventricular cardiomyocytes in vitro, under basal conditions and after glucose deprivation. Conversely, lentivirus-delivered shRNA against p27 successfully reduced p27 levels and suppressed basal and glucose-deprived levels of autophagy in cardiomyocytes in vitro. Glucose deprivation mimics myocardial ischemia and induces apoptosis in cardiomyocytes. During glucose deprivation, TAT-p27 inhibited apoptosis, whereas down-regulation of p27 decreased survival of cardiomyocytes. However, inhibition of autophagy by pharmacological (3-methyladenine, chloroquine, or bafilomycin A1) or genetic approaches (siRNA-mediated knockdown of Atg5) sensitized cardiomyocytes to glucose deprivation-induced apoptosis, even in the presence of TAT-p27. TAT-p27 was also able to provoke greater levels of autophagy in resting and fasting cardiomyocytes in vivo. Further, TAT-p27 enhanced autophagy and repressed cardiomyocytes apoptosis, improved cardiac function, and reduced infarct size following myocardial infarction. Again, these effects were lost when cardiac autophagy in vivo was blocked by chloroquine. Taken together, these data show that p27 positively regulates cardiac autophagy in vitro and in vivo, at rest and after metabolic stress, and that TAT-p27 inhibits apoptosis by promoting autophagy in glucose-deprived cardiomyocytes in vitro and in post-myocardial infarction hearts in vivo. 相似文献
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Gessner Arne Mieth Maren Auge Daniel Chafai Anja Müller Fabian Fromm Martin F. Maas Renke 《Amino acids》2019,51(9):1259-1271
Amino Acids - Cardiovascular disease (CVD) and chronic kidney disease (CKD) constitute substantial burdens for public health. The identification and validation of risk markers for CVD and CKD in... 相似文献
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