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Curt R. Fischer Paul Wilmes Benjamin P. Bowen Trent R. Northen Jillian F. Banfield 《Metabolomics : Official journal of the Metabolomic Society》2012,8(4):566-578
Natural microbial communities are extremely diverse and contain uncharacterized but functionally important small molecules. By coupling a deuterium (D) labeling technique to high mass accuracy untargeted liquid chromatography-electrospray ionization-mass spectrometry (LC?CESI?CMS) metabolomic analysis, we found that natural acidophilic microbial biofilms dominated by bacteria of the genus Leptospirillum contained unusual lyso phosphatidylethanolamine (PE) lipids in high abundance (more than 10?nmol/mg of dry biomass). The unusual polar head group structure of these lipids is similar to lipids found in phylogenetically unrelated acidophilic chemoautolithotrophs and may be related to the affinity of these lipids for iron and calcium ions. Correlations of lyso phospholipid and proteome abundance patterns suggest a link between the lyso phospholipids and the UBA-type substrain of Leptospirillum group II. By combining untargeted metabolomics with D exchange we demonstrate the ability to identify cryptic but biologically functional small molecules in mixed microbial communities. 相似文献
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Meredith Whitehead Syabira Yusoff Sadia Ahmad Lukas Schmidt Manuel Mayr Jillian Madine David Middleton Catherine M. Shanahan 《Aging cell》2023,22(2):e13746
Vascular amyloidosis, caused when peptide monomers aggregate into insoluble amyloid, is a prevalent age-associated pathology. Aortic medial amyloid (AMA) is the most common human amyloid and is composed of medin, a 50-amino acid peptide. Emerging evidence has implicated extracellular vesicles (EVs) as mediators of pathological amyloid accumulation in the extracellular matrix (ECM). To determine the mechanisms of AMA formation with age, we explored the impact of vascular smooth muscle cell (VSMC) senescence, EV secretion, and ECM remodeling on medin accumulation. Medin was detected in EVs secreted from primary VSMCs. Small, round medin aggregates colocalized with EV markers in decellularized ECM in vitro and medin was shown on the surface of EVs deposited in the ECM. Decreasing EV secretion with an inhibitor attenuated aggregation and deposition of medin in the ECM. Medin accumulation in the aortic wall of human subjects was strongly correlated with age and VSMC senescence increased EV secretion, increased EV medin loading and triggered deposition of fibril-like medin. Proteomic analysis showed VSMC senescence induced changes in EV cargo and ECM composition, which led to enhanced EV-ECM binding and accelerated medin aggregation. Abundance of the proteoglycan, HSPG2, was increased in the senescent ECM and colocalized with EVs and medin. Isolated EVs selectively bound to HSPG2 in the ECM and its knock-down decreased formation of fibril-like medin structures. These data identify VSMC-derived EVs and HSPG2 in the ECM as key mediators of medin accumulation, contributing to age-associated AMA development. 相似文献
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Stella Charleson Jillian F. Evans Robert J. Zamboni Yves Leblanc Brian J. Fitzsimmons Claire Leveill Philippe Dupuis Anthony W. Ford-Hutchinson 《Prostaglandins & other lipid mediators》1986,32(4)
Specific high-affinity binding sites for [3H]-leukotriene B4 have been identified on membrane preparations from rat and human leukocytes. The rat and human leukocyte membrane preparations show linearity of binding with increasing protein concentration, saturable binding and rapid dissociation of binding by excess unlabelled leukotriene B4. Dissociation constants of 0.5 to 2.5 nM and maximum binding of 5000 fmoles/mg protein were obtained for [3H] leukotriene B4 binding to these preparations. Displacement of [3H]-leukotriene B4 by leukotriene B4 was compared with displacement by leukotriene B3 and leukotriene B5 which differ from leukotriene B4 only by the absence of a double bond at carbon 14 or the presence of an additional double bond at carbon 17, respectively. Leukotriene B3 was shown to be equipotent to leukotriene B4 in ability to displace [3H]-leukotriene B4 from both rat and human leukocyte membranes while leukotriene B5 was 20–50 fold less potent. The relative potencies for the displacement of [3]-leukotriene B4 by leukotrienes B3, B4 and B5 on rat and human leukocyte membranes were shown to correlate well with their potencies for the induction of the aggregation of rat leukocytes and the chemokinesis of human leukocytes. 相似文献
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Karen Andrade J?rn Logemann Karla B Heidelberg Joanne B Emerson Luis R Comolli Laura A Hug Alexander J Probst Angus Keillar Brian C Thomas Christopher S Miller Eric E Allen John W Moreau Jochen J Brocks Jillian F Banfield 《The ISME journal》2015,9(12):2697-2711
Marine microbial communities experience daily fluctuations in light and temperature that can have important ramifications for carbon and nutrient cycling. Elucidation of such short time scale community-wide dynamics is hindered by system complexity. Hypersaline aquatic environments have lower species richness than marine environments and can be well-defined spatially, hence they provide a model system for diel cycle analysis. We conducted a 3-day time series experiment in a well-defined pool in hypersaline Lake Tyrrell, Australia. Microbial communities were tracked by combining cultivation-independent lipidomic, metagenomic and microscopy methods. The ratio of total bacterial to archaeal core lipids in the planktonic community increased by up to 58% during daylight hours and decreased by up to 32% overnight. However, total organism abundances remained relatively consistent over 3 days. Metagenomic analysis of the planktonic community composition, resolved at the genome level, showed dominance by Haloquadratum species and six uncultured members of the Halobacteriaceae. The post 0.8 μm filtrate contained six different nanohaloarchaeal types, three of which have not been identified previously, and cryo-transmission electron microscopy imaging confirmed the presence of small cells. Notably, these nano-sized archaea showed a strong diel cycle, with a pronounced increase in relative abundance over the night periods. We detected no eukaryotic algae or other photosynthetic primary producers, suggesting that carbon resources may derive from patchily distributed microbial mats at the sediment-water interface or from surrounding land. Results show the operation of a strong community-level diel cycle, probably driven by interconnected temperature, light abundance, dissolved oxygen concentration and nutrient flux effects. 相似文献