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991.
Vera Muders Silke Kerruth Víctor A. Lórenz-Fonfría Christian Bamann Joachim Heberle Ramona Schlesinger 《FEBS letters》2014
Channelrhodopsin-1 from Chlamydomonas augustae (CaChR1) is a light-activated cation channel, which is a promising optogenetic tool. We show by resonance Raman spectroscopy and retinal extraction followed by high pressure liquid chromatography (HPLC) that the isomeric ratio of all-trans to 13-cis of solubilized channelrhodopsin-1 is with 70:30 identical to channelrhodopsin-2 from Chlamydomonas reinhardtii (CrChR2). Critical frequency shifts in the retinal vibrations are identified in the Raman spectrum upon transition to the open (conductive P2380) state. Fourier transform infrared spectroscopy (FTIR) spectra indicate different structures of the open states in the two channelrhodopsins as reflected by the amide I bands and the protonation pattern of acidic amino acids. 相似文献
992.
Christian G. Ramos André M. Grilo Sílvia A. Sousa Joana R. Feliciano Paulo J. P. da Costa Jorge H. Leit?o 《PloS one》2014,9(6)
Small non-coding RNAs (sRNAs) are important players of gene expression regulation in bacterial pathogens. MtvR is a 136-nucleotide long sRNA previously identified in the human pathogen Burkholderia cenocepacia J2315 and with homologues restricted to bacteria of the Burkholderia cepacia complex. In this work we have investigated the effects of expressing MtvR in Escherichia coli and Pseudomonas aeruginosa. Results are presented showing that MtvR negatively regulates the hfq mRNA levels in both bacterial species. In the case of E. coli, this negative regulation is shown to involve binding of MtvR to the 5′-UTR region of the hfqEc mRNA. Results presented also show that expression of MtvR in E. coli and P. aeruginosa originates multiple phenotypes, including reduced resistance to selected stresses, biofilm formation ability, and increased susceptibility to various antibiotics. 相似文献
993.
Ferruh Artunc Christian Mueller Tobias Breidthardt Raphael Twerenbold Andreas Peter Claus Thamer Peter Weyrich Hans-Ulrich Haering Bjoern Friedrich 《PloS one》2012,7(10)
Background
In hemodialysis patients, elevated plasma troponin concentrations are a common finding that has even increased with the advent of newly developed sensitive assays. However, the interpretation and relevance of this is still under debate.Methods
In this cross-sectional study, we analyzed plasma concentrations of sensitive troponin I (TnI) and troponin T (TnT) in stable ambulatory hemodialysis patients (n = 239) and investigated their associations with clinical factors and mortality.Results
In all of the enrolled patients, plasma TnI or TnT was detectable at a median concentration of 14 pg/ml (interquartile range: 7–29) using the Siemens TnI ultra assay and 49 pg/ml (31–74) using the Roche Elecsys high sensitive TnT assay. Markedly more patients exceeded the 99th percentile for TnT than for TnI (95% vs. 14%, p<0.0001). In a multivariate linear regression model, TnT was independently associated with age, gender, systolic dysfunction, time on dialysis, residual diuresis and systolic blood pressure, whereas TnI was independently associated with age, systolic dysfunction, pulse pressure, time on dialysis and duration of a HD session. During a follow-up period of nearly two years, TnT concentration above 38 pg/mL was associated with a 5-fold risk of death, whereas elevation of TnI had a gradual association to mortality.Conclusion
In hemodialysis patients, elevations of plasma troponin concentrations are explained by cardiac function and dialysis-related parameters, which contribute to cardiac strain. Both are highly predictive of increased risk of death. 相似文献994.
995.
The relative contribution of compositional and structural heterogeneity on biodiversity is currently ambiguous because field studies generally integrate these two sources of habitat heterogeneity into a single index. We established the relationship between species richness of ground-dwelling and flying beetles and compositional and structural attributes of forest heterogeneity. The relationship was evaluated at two spatial scales: the scale of forest stand, corresponding to an 11.3 m radius, and the scale of landscape, corresponding to either a 400 or 800 m radius. Seventy stands were sampled in the matrix of old-growth boreal forest of the North Shore region of Québec, Canada, during the summers of 2004 and 2005. A total of 133 ground-dwelling beetle species (range: 4–42 species per site) were captured in the pitfall traps and 251 flying species (range 16–58 species per site) in flight-interception traps. We found that the most relevant type of heterogeneity to explain variations in species richness and the significance of landscape scale information varied between groups of beetles. Compositional heterogeneity (i.e. the number of species of forest trees and shrubs) at the stand scale best predicted species richness in ground-dwelling beetles. On the other hand, it was the combined influence of structural and compositional habitat heterogeneity at stand and landscape scales that best explained richness patterns in flying beetles. Our study outlines the significance of considering multiple types and spatial scales of habitat heterogeneity when describing patterns of species richness. 相似文献
996.
Chen Liu Nadeem Wajih Xiaohua Liu Swati Basu John Janes Madison Marvel Christian Keggi Christine C. Helms Amber N. Lee Andrea M. Belanger Debra I. Diz Paul J. Laurienti David L. Caudell Jun Wang Mark T. Gladwin Daniel B. Kim-Shapiro 《The Journal of biological chemistry》2015,290(2):1281-1294
Nitrite signaling likely occurs through its reduction to nitric oxide (NO). Several reports support a role of erythrocytes and hemoglobin in nitrite reduction, but this remains controversial, and alternative reductive pathways have been proposed. In this work we determined whether the primary human erythrocytic nitrite reductase is hemoglobin as opposed to other erythrocytic proteins that have been suggested to be the major source of nitrite reduction. We employed several different assays to determine NO production from nitrite in erythrocytes including electron paramagnetic resonance detection of nitrosyl hemoglobin, chemiluminescent detection of NO, and inhibition of platelet activation and aggregation. Our studies show that NO is formed by red blood cells and inhibits platelet activation. Nitric oxide formation and signaling can be recapitulated with isolated deoxyhemoglobin. Importantly, there is limited NO production from erythrocytic xanthine oxidoreductase and nitric-oxide synthase. Under certain conditions we find dorzolamide (an inhibitor of carbonic anhydrase) results in diminished nitrite bioactivation, but the role of carbonic anhydrase is abrogated when physiological concentrations of CO2 are present. Importantly, carbon monoxide, which inhibits hemoglobin function as a nitrite reductase, abolishes nitrite bioactivation. Overall our data suggest that deoxyhemoglobin is the primary erythrocytic nitrite reductase operating under physiological conditions and accounts for nitrite-mediated NO signaling in blood. 相似文献
997.
The presence of serotonin 5-HT1A receptors and their physiological role were further characterized in the goldfish retina. The effects of the 5-HT6/7 receptor antagonists pimozide, fluphenazine and amoxapine, the 5-HT1A receptor antagonist WAY-100,135, and the alkylating agent N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline, on the 5-HT1A receptor agonist [3H]8-hydroxy-2-(di-n-propylamino)tetralin binding to retinal membranes, were evaluated. In addition, the effects of serotonin, 8-hydroxy-2-(di-n-propylamino)tetralin, WAY-100,135, the adenylate cyclase inhibitors SQ22536 and MDL12330A, and the cyclic AMP analog 8-bromoadenosine-3:5 cyclic monophosphate were also studied on neuritic outgrowth from retinal explants. WAY-100,135 but not 5-HT6/7receptor antagonists inhibited [3H]8-hydroxy-2-(di-n-propylamino)tetralin binding to retinal membranes N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline decreased [3H]8-hydroxy-2-(di-n-propylamino)tetralin binding sites up to 70%, while receptor turnover was similar to that reported in other tissues. Serotonin and 8-hydroxy-2-(di-n-propylamino)tetralin stimulated cyclic AMP production, both ex vivo and in vitro, and these increases were related to inhibition of neuritic outgrowth. The inhibitory effect was reduced by SQ22536 and by WAY-100,135, and was mimicked by 8-bromoadenosine-3:5cyclic monophosphate. This study supports previous findings about the role of serotonin as a regulator of axonal outgrowth during in vitro regeneration of the goldfish retina and demonstrates that this effect is mediated, at least in part, by 5-HT1A receptors through a mechanism which involves an increase of cyclic AMP levels. 相似文献
998.
999.
Christian O. Obuekwe Zamya K. Al-Jadi Esmaeil S. Al-Saleh 《International biodeterioration & biodegradation》2009,63(3):273-279
Forty six bacterial isolates able to grow on crude oil were isolated from various hydrocarbon-contaminated sites in Kuwait. The extent of crude oil degradation varied over a wide range (1–87%) among the isolates. Isolates were predominantly Gram-positive bacteria (79% of total isolates) belonging to the genera Bacillus (93%) and Paenibacillus (7%). Among the few Gram-negative isolates were from the genera Acinetobacter, Alcaligenes, Klebsiella, Burkholderia, Pseudomonas, and Williamsia. Analyses of their cell-surface hydrophobicity (CSH) by various methods equally showed a wide variation among the isolates. About 74% of isolates that degraded significant amounts of crude oil (>40% degradation) possessed high level of CSH, while 58% of all the isolates exhibited high levels of CSH. Statistical analyses showed significantly high correlation between the ability to degrade crude oil and CSH. The ability of the isolates to bind to polystyrene and salt-aggregation test as measures of CSH were more strongly correlated with hydrocarbon-degrading ability than adherence to hydrocarbons. 相似文献
1000.
Gutsch R Kandemir JD Pietsch D Cappello C Meyer J Simanowski K Huber R Brand K 《The Journal of biological chemistry》2011,286(26):22716-22729