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321.
Melody Handali Durga P. Neupane Hridindu Roychowdhury Erik T. Yukl 《The Journal of biological chemistry》2015,290(19):11878-11889
ATP-binding cassette (ABC) transporters of the cluster 9 family are ubiquitous among bacteria and essential for acquiring Zn2+ and Mn2+ from the environment or, in the case of pathogens, from the host. These rely on a substrate-binding protein (SBP) to coordinate the relevant metal with high affinity and specificity and subsequently release it to a membrane permease for translocation into the cytoplasm. Although a number of cluster 9 SBP structures have been determined, the structural attributes conferring Zn2+ or Mn2+ specificity remain ambiguous. Here we describe the gene expression profile, in vitro metal binding properties, and crystal structure of a new cluster 9 SBP from Paracoccus denitrificans we have called AztC. Although all of our results strongly indicate Zn2+ over Mn2+ specificity, the Zn2+ ion is coordinated by a conserved Asp residue only observed to date as a metal ligand in Mn2+-specific SBPs. The unusual sequence properties of this protein are shared among close homologues, including members from the human pathogens Klebsiella pneumonia and Enterobacter aerogenes, and would seem to suggest a subclass of Zn2+-specific transporters among the cluster 9 family. In any case, the unusual coordination environment of AztC expands the already considerable range of those available to Zn2+-specific SBPs and highlights the presence of a His-rich loop as the most reliable indicator of Zn2+ specificity. 相似文献
322.
Dr. Ralph O. Brinkhurst Dr. Peter M. Chapman Ms. Melody A. Farrell 《International Review of Hydrobiology》1983,68(5):683-699
Aquatic oligochaete species selected on the basis of pollution tolerance or intolerance as determined from field studies were used to determine respiration rates under standard conditions, after exposure to sublethal levels of environmental variables (pH, salinity, temperature) or toxicants (Cd, Hg, NaPCP) alone or in pairs. Respiration rates, critical oxygen levels and degree of regulation were not correlated with field-determined tolerance to organic pollution. Stress factors caused increased or lowered respiration rate, loss of regulation (partial or total) and sometimes shifts in critical oxygen level. Regulation was improved in the face of some stresses. Combined stresses produced additional changes in respiration rates and regulation. These responses were complex, which makes them useful indicators of specific stress factors but also indicate complex mechanisms behind the observed changes. 相似文献
323.
Comparative analysis of human 19p12-13 region in Fugu and mouse 总被引:2,自引:0,他引:2
324.
The technique of in situ hybridization to both meiotic and mitotic chromosomes of Rumex acetosa is described. Differences in the efficiency of signal detection were observed between the two types of material. The implications of these results for in situ hybridization to other plant species are explored. 相似文献
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Daniel R. Colman Melody R. Lindsay Annette Harnish Evan M. Bilbrey Maximiliano J. Amenabar Matthew J. Selensky Kristopher M. Fecteau Randall V. Debes II Matthew B. Stott Everett L. Shock Eric S. Boyd 《Environmental microbiology》2021,23(7):4034-4053
Hot springs integrate hydrologic and geologic processes that vary over short- and long-term time scales. However, the influence of temporal hydrologic and geologic change on hot spring biodiversity is unknown. Here, we coordinated near-weekly, cross-seasonal (~140 days) geochemical and microbial community analyses of three widely studied hot springs with local precipitation data in Yellowstone National Park. One spring (‘HFS’) exhibited statistically significant, coupled microbial and geochemical variation across seasons that was associated with recent precipitation patterns. Two other spring communities, ‘CP’ and ‘DS’, exhibited minimal to no variation across seasons. Variability in the seasonal response of springs is attributed to differences in the timing and extent of aquifer recharge with oxidized near-surface water from precipitation. This influx of oxidized water is associated with changes in community composition, and in particular, the abundances of aerobic sulfide-/sulfur-oxidizers that can acidify waters. During sampling, a new spring formed after a period of heavy precipitation and its successional dynamics were also influenced by surface water recharge. Collectively, these results indicate that changes in short-term hydrology associated with precipitation can impact hot spring geochemistry and microbial biodiversity. These results point to potential susceptibility of certain hot springs and their biodiversity to sustained, longer-term hydrologic changes. 相似文献
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Dong Melody L. Lan Ingrid S. Yang Weiguang Rabinovitch Marlene Feinstein Jeffrey A. Marsden Alison L. 《Biomechanics and modeling in mechanobiology》2021,20(6):2471-2489
Biomechanics and Modeling in Mechanobiology - Untreated ventricular septal defects (VSDs) can lead to pulmonary arterial hypertension (PAH) characterized by elevated pulmonary artery (PA) pressure... 相似文献