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排序方式: 共有991条查询结果,搜索用时 15 毫秒
111.
Schumacher MA Ye Q Barge MT Zampini M Barillà D Hayes F 《The Journal of biological chemistry》2012,287(31):26146-26154
Segregation of the bacterial multidrug resistance plasmid TP228 requires the centromere-binding protein ParG, the parH centromere, and the Walker box ATPase ParF. The cycling of ParF between ADP- and ATP-bound states drives TP228 partition; ATP binding stimulates ParF polymerization, which is essential for segregation, whereas ADP binding antagonizes polymerization and inhibits DNA partition. The molecular mechanism involved in this adenine nucleotide switch is unclear. Moreover, it is unknown how any Walker box protein polymerizes in an ATP-dependent manner. Here, we describe multiple ParF structures in ADP- and phosphomethylphosphonic acid adenylate ester (AMPPCP)-bound states. ParF-ADP is monomeric but dimerizes when complexed with AMPPCP. Strikingly, in ParF-AMPPCP structures, the dimers interact to create dimer-of-dimer "units" that generate a specific linear filament. Mutation of interface residues prevents both polymerization and DNA segregation in vivo. Thus, these data provide insight into a unique mechanism by which a Walker box protein forms polymers that involves the generation of ATP-induced dimer-of-dimer building blocks. 相似文献
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Piepoli A Tavano F Copetti M Mazza T Palumbo O Panza A di Mola FF Pazienza V Mazzoccoli G Biscaglia G Gentile A Mastrodonato N Carella M Pellegrini F di Sebastiano P Andriulli A 《PloS one》2012,7(3):e33663
Background and Aim
Altered expression of microRNAs (miRNAs) hallmarks many cancer types. The study of the associations of miRNA expression profile and cancer phenotype could help identify the links between deregulation of miRNA expression and oncogenic pathways.Methods
Expression profiling of 866 human miRNAs in 19 colorectal and 17 pancreatic cancers and in matched adjacent normal tissues was investigated. Classical paired t-test and random forest analyses were applied to identify miRNAs associated with tissue-specific tumors. Network analysis based on a computational approach to mine associations between cancer types and miRNAs was performed.Results
The merge between the two statistical methods used to intersect the miRNAs differentially expressed in colon and pancreatic cancers allowed the identification of cancer-specific miRNA alterations. By miRNA-network analysis, tissue-specific patterns of miRNA deregulation were traced: the driving miRNAs were miR-195, miR-1280, miR-140-3p and miR-1246 in colorectal tumors, and miR-103, miR-23a and miR-15b in pancreatic cancers.Conclusion
MiRNA expression profiles may identify cancer-specific signatures and potentially useful biomarkers for the diagnosis of tissue specific cancers. miRNA-network analysis help identify altered miRNA regulatory networks that could play a role in tumor pathogenesis. 相似文献114.
Giovanni Minardi Giordano Zampi Amedeo Pergolini Giovanni Pulignano Massimiliano Scappaticci Francesca Moschella Orsini Gaetano Pero Paola Lilla Della Monica Giovanni Cioffi Francesco Musumeci 《Cardiovascular ultrasound》2012,10(1):1-7
Background
Cardiac allograft vasculopathy (CAV) is a major late complication in cardiac transplant recipients and has a relevant impact on outcome of these patients. Aims of this study: to compare, in cardiac transplant recipients patients, the diagnostic value of pressure/volume relationship (ESPVR) during dobutamine stress echocardiography (DSE) for coronary artery disease, assessed by Multislice Computed Tomography (MSCT), and by coronary angiography (CA). We also analyzed any possible relationship between ESPVR and the Health Related Quality of Life of the patients (HRQoL), evaluated by SF–36 questionnaire.Methods
25 consecutive patients underwent DSE within 24 hours after MSCT coronary angiogram and then they underwent CA. The HRQoL questionnaire was administered to the patients in the settings of DSE. They were followed-up for 6 months.Results
DSE has a sensitivity in detecting CAV of 67%, specificity of 95%, positive predictive value of 67% and negative predictive value of 95%; DSE with ESPVR has a sensitivity of 100%, specificity of 95%, positive predictive value of 75%, negative predictive value of 100%; MSCT has a sensitivity of 100%; specificity of 82%; positive predictive value of 43%; negative predictive value of 100%. Htx recipients with a flat-biphasic ESPVR, although asymptomatic, perceived a worst HRQoL compared with the up-sloping ESPVR population, and this is statistically significant for the general health (p 0.0004), the vitality (p 0.0013) and the mental health (p 0.021) SF-36 subscale.Conclusions
Evaluation with DSE and ESPVR is accurate in the clinical control of heart transplant recipients reserving invasive evaluation only for patients with abnormal contractility indexes. 相似文献115.
Bensi G Mora M Tuscano G Biagini M Chiarot E Bombaci M Capo S Falugi F Manetti AG Donato P Swennen E Gallotta M Garibaldi M Pinto V Chiappini N Musser JM Janulczyk R Mariani M Scarselli M Telford JL Grifantini R Norais N Margarit I Grandi G 《Molecular & cellular proteomics : MCP》2012,11(6):M111.015693
We propose an experimental strategy for highly accurate selection of candidates for bacterial vaccines without using in vitro and/or in vivo protection assays. Starting from the observation that efficacious vaccines are constituted by conserved, surface-associated and/or secreted components, the strategy contemplates the parallel application of three high throughput technologies, i.e. mass spectrometry-based proteomics, protein array, and flow-cytometry analysis, to identify this category of proteins, and is based on the assumption that the antigens identified by all three technologies are the protective ones. When we tested this strategy for Group A Streptococcus, we selected a total of 40 proteins, of which only six identified by all three approaches. When the 40 proteins were tested in a mouse model, only six were found to be protective and five of these belonged to the group of antigens in common to the three technologies. Finally, a combination of three protective antigens conferred broad protection against a panel of four different Group A Streptococcus strains. This approach may find general application as an accelerated and highly accurate path to bacterial vaccine discovery. 相似文献
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Soto G Setten L Lisi C Maurelis C Mozzicafreddo M Cuccioloni M Angeletti M Ayub ND 《Extremophiles : life under extreme conditions》2012,16(3):455-462
Polyhydroxybutyrate (PHB), a typical carbon and energy storage compound, is widely found in Bacteria and Archae domains. This
polymer is produced in response to conditions of physiological stress. PHB is composed of repeating units of β-hydroxybutyrate
(R-3HB). It has been previously shown that R-3HB functions as an osmolyte in extremophile strains. In this study, Pseudomonas sp. CT13, a halotolerant bacterium, and its PHB synthase-minus mutant (phaC) were used to analyze the chaperone role of R-3HB. The production of this compound was found to be essential to salt stress
resistance and positively correlated with salt concentration, suggesting that PHB monomer acts as a compatible solute in Pseudomonas sp. CT13. R-3HB accumulation was also associated with the prevention of protein aggregation under combined salt and thermal
stresses in Pseudomonas sp. CT13. Physiological concentrations of R-3HB efficiently reduced citrate synthase (CS) aggregation and stabilized the
enzymatic activities of CS during thermal stress. Docking analysis of the CS/R-3HB interaction predicted the stability of
this complex under physiological concentrations of R-3HB. Thus, in vivo, in vitro and in silico analyses suggest that R-3HB
can act as a chemical chaperone. 相似文献