Microbial communities in cores obtained from methane hydrate-bearing deep marine sediments (down to more than 300 m below the seafloor) in the forearc basin of the Nankai Trough near Japan were characterized with cultivation-dependent and -independent techniques. Acridine orange direct count data indicated that cell numbers generally decreased with sediment depth. Lipid biomarker analyses indicated the presence of viable biomass at concentrations greater than previously reported for terrestrial subsurface environments at similar depths. Archaeal lipids were more abundant than bacterial lipids. Methane was produced from both acetate and hydrogen in enrichments inoculated with sediment from all depths evaluated, at both 10 and 35°C. Characterization of 16S rRNA genes amplified from the sediments indicated that archaeal clones could be discretely grouped within the Euryarchaeota and Crenarchaeota domains. The bacterial clones exhibited greater overall diversity than the archaeal clones, with sequences related to the Bacteroidetes, Planctomycetes, Actinobacteria, Proteobacteria, and green nonsulfur groups. The majority of the bacterial clones were either members of a novel lineage or most closely related to uncultured clones. The results of these analyses suggest that the microbial community in this environment is distinct from those in previously characterized methane hydrate-bearing sediments.

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Addition of molasses and urea was tested as a means of stimulating microbial urea hydrolysis in the Eastern Snake River Plain Aquifer in Idaho. Ureolysis is an integral component of a novel remediation approach for divalent trace metal and radionuclide contaminants in groundwater and associated geomedia, where the contaminants are immobilized by coprecipitation in calcite. Generation of carbonate alkalinity from ureolysis promotes calcite precipitation. In calcite-saturated aquifers, this represents a potential long-term contaminant sequestration mechanism. In a single-well experiment, dilute molasses was injected three times over two weeks to promote overall microbial growth, followed by one urea injection. With molasses addition, total cell numbers in the groundwater increased 1-2 orders of magnitude. Estimated ureolysis rates in recovered groundwater samples increased from < 0.1 to > 25 nmol L(-1) hr(-1). A quantitative PCR assay for the bacterial ureC gene indicated that urease gene numbers increased up to 170 times above pre-injection levels. Following urea injection, calcite precipitates were recovered. Estimated values for an in situ first order ureolysis rate constant ranged from 0.016 to 0.057 d(-1). Although collateral impacts such as reduced permeability were observed, overall results indicated the viability of manipulating biogeochemical processes to promote contaminant sequestration.

Abstract-Strontium incorporation into calcite generated by bacterial ureolysis was investigated as part of an assessment of a proposed remediation approach for 90 Sr contamination in groundwater. Urea hydrolysis produces ammonium and carbonate and elevates pH, resulting in the promotion of calcium carbonate precipitation. Urea hydrolysis by the bacterium Bacillus pasteurii in a medium designed to mimic the chemistry of the Snake River Plain Aquifer in Idaho resulted in a pH rise from 7.5 to 9.1. Measured average distribution coefficients (D EX ) for Sr in the calcite produced by ureolysis (0.5) were up to an order of magnitude higher than values reported in the literature for natural and synthetic calcites (0.02-0.4). They were also higher than values for calcite produced abiotically by ammonium carbonate addition (0.3). The precipitation of calcite in these experiments was verified by X-ray diffraction. Time-of-flight secondary ion mass spectrometry (ToF SIMS) depth profiling (up to 350 nm) suggested that the Sr was not merely sorbed on the surface, but was present at depth within the particles. X-ray absorption near edge spectra showed that Sr was present in the calcite samples as a solid solution. The extent of Sr incorporation appeared to be driven primarily by the overall rate of calcite precipitation, where faster precipitation was associated with greater Sr uptake into the solid. The presence of bacterial surfaces as potential nucleation sites in the ammonium carbonate precipitation treatment did not enhance overall precipitation or the Sr distribution coefficient. Because bacterial ureolysis can generate high rates of calcite precipitation, the application of this approach is promising for remediation of 90 Sr contamination in environments where calcite is stable over the long term.

Abstract-Clinical reports indicate that patients with primary aldosteronism commonly have impaired glucose tolerance; however, the relationship between aldosterone and insulin signaling pathway has not been clarified. In this study, we examined the effects of aldosterone treatment on insulin receptor substrate-1 expression and insulin signaling pathway including Akt phosphorylation and glucose uptake in rat vascular smooth muscle cells. Insulin receptor substrate-1 protein expression and Akt phosphorylation were determined by Western blot analysis with anti-insulin receptor substrate-1 and phosphorylated-Akt antibodies, respectively. Glucose metabolism was evaluated using 3 H-labeled 2-deoxy-D-glucose uptake. Aldosterone (1-100 nmol/L) dose-dependently decreased insulin receptor substrate-1 protein expression with a peak at 18 hours (nϭ4). Aldosterone-induced degradation of insulin receptor substrate-1 was markedly attenuated by treatment with the selective mineralocorticoid receptor antagonist eplerenone (10 mol/L; nϭ4). Furthermore, degradation was blocked by the Src inhibitor PP1 (20 mol/L; nϭ4). Treatment with antioxidants, N-acetylcysteine (10 mmol/L), or ebselen (40 mol/L) also attenuated aldosterone-induced insulin receptor substrate-1 degradation (nϭ4). In addition, proteasome inhibitor MG132 (1 mol/L) prevented insulin receptor substrate-1 degradation (nϭ4). Aldosterone treatment abolished insulin-induced Akt phosphorylation (100 nmol/L; 5 minutes; nϭ4). Furthermore, aldosterone pretreatment decreased insulin-stimulated (100 nmol/L; 60 minutes; nϭ4) glucose uptake by 50%, which was reversed by eplerenone (10 mol/L; nϭ4). These data indicate that aldosterone decreases insulin receptor substrate-1 expression via Src and reactive oxygen species stimulation by proteasome-dependent degradation in vascular smooth muscle cells; thus, aldosterone may be involved in the pathogenesis of vascular insulin resistance via oxidative stress. Key Words: aldosterone Ⅲ oxidative stress Ⅲ insulin receptor substrate-1 Ⅲ insulin resistance Ⅲ type 2 diabetes mellitus Ⅲ metabolic syndrome Ⅲ eplerenone I nsulin resistance is a key attribute of type 2 diabetes and the metabolic syndrome. 1,2 Systemic glucose metabolism is maintained in the liver and skeletal muscle, and in the insulin resistant state, insulin-stimulated glucose uptake is attenuated and accompanied with subsequent increases in blood glucose concentration. High blood glucose concentration induces secretion of insulin from the pancreas and results in hyperinsulinemia. Both hyperglycemia and hyperinsulinemia affect the vasculature and are associated with microangiopathy, including retinopathy and nephropathy, and macroangiopathy, including cardiovascular disease and atherosclerosis. 3 Insulin resistance in the vasculature might also affect systemic glucose metabolism. However, the involvement of normal insulin signaling contributes to arteriosclerosis. 4,5 On the other hand, serine phosphorylation and degradation of insulin receptor substrate-1 (IRS-1) is a possible...

The present study provides evidence that the LOX-1-MT1-MMP axis plays a crucial role in RhoA and Rac1 activation signalling pathways in ox-LDL stimulation, suggesting that this axis may be a promising target for treating endothelial dysfunction.

With the increasing demand for rare earth elements (REEs) in many emerging clean energy technologies, there is an urgent need for the development of new approaches for efficient REE extraction and recovery. As a step towards this goal, we genetically engineered the aerobic bacterium Caulobacter crescentus for REE adsorption through high-density cell surface display of lanthanide binding tags (LBTs) on its S-layer. The LBT-displayed strains exhibited enhanced adsorption of REEs compared to cells lacking LBT, high specificity for REEs, and an adsorption preference for REEs with small atomic radii. Adsorbed Tb3+ could be effectively recovered using citrate, consistent with thermodynamic speciation calculations that predicted strong complexation of Tb3+ by citrate. No reduction in Tb3+ adsorption capacity was observed following citrate elution, enabling consecutive adsorption/desorption cycles. The LBT-displayed strain was effective for extracting REEs from the acid leachate of core samples collected at a prospective rare earth mine. Our collective results demonstrate a rapid, efficient and reversible process for REE adsorption with potential industrial application for REE enrichment and separation.