Vanadate

About: Vanadate is a research topic. Over the lifetime, 4497 publications have been published within this topic receiving 120109 citations. The topic is also known as: vanadate.

Multifunctional Rare-Earth Vanadate Nanoparticles: Luminescent Labels, Oxidant Sensors, and MRI Contrast Agents

Abstract: Collecting information on multiple pathophysiological parameters is essential for understanding complex pathologies, especially given the large interindividual variability. We report here multifunctional nanoparticles which are luminescent probes, oxidant sensors, and contrast agents in magnetic resonance imaging (MRI). Eu3+ ions in an yttrium vanadate matrix have been demonstrated to emit strong, nonblinking, and stable luminescence. Time- and space-resolved optical oxidant detection is feasible after reversible photoreduction of Eu3+ to Eu2+ and reoxidation by oxidants, such as H2O2, leading to a modulation of the luminescence emission. The incorporation of paramagnetic Gd3+ confers in addition proton relaxation enhancing properties to the system. We synthesized and characterized nanoparticles of either 5 or 30 nm diameter with compositions of GdVO4 and Gd0.6Eu0.4VO4. These particles retain the luminescence and oxidant detection properties of YVO4:Eu. Moreover, the proton relaxivity of GdVO4 and Gd0.6Eu...

Insulin-Like Effects of Vanadate in Isolated Rat Adipocytes*

Abstract: Vanadate has been shown to have a number of insulin-like effects in various cells, including isolated rat adipocytes. In the present study we compared the activities of vanadate and insulin in isolated fat cells using a number of different assays of insulin-like activity. Both insulin and vanadate stimulated [2-3H]glucose incorporation into fat cell lipid in a dose-dependent manner, but the maximal effect of vanadate was markedly greater than that of insulin. At 10(-2) M vanadate the effect was 3-4 times as great as the maximal effect of insulin. This effect was dependent on specific glucose transport. Combinations of insulin and vanadate were not more effective than vanadate alone. Vanadate also produced antilipolysis with an effect somewhat greater than that of insulin. Using [U-14C]glucose both vanadate and insulin stimulated 14CO2 production and [14C]glucose incorporation into lipid, and again the effect of vanadate was greater than that of insulin. Vanadate had a greater effect on 14CO2 production than on [14C]glucose incorporation into lipid. When [1-14C]glucose was used vanadate again had a significantly greater effect on 14CO2 production than did insulin, but when [6-14C]glucose was used the effects of vanadate and insulin were equal. These results demonstrate that vanadate has insulin-like effects in isolated fat cells, but it selectively stimulates certain pathways to a greater extent than does insulin. The greater effect of vanadate than insulin appears to be primarily on the pentose phosphate shunt, suggesting that this agent may be useful for examination of this intracellular pathway in fat cells.

Hydrogen sulfide is involved in maintaining ion homeostasis via regulating plasma membrane Na+/H+ antiporter system in the hydrogen peroxide-dependent manner in salt-stress Arabidopsis thaliana root.

Abstract: Hydrogen sulfide (H2S) and hydrogen peroxide (H2O2) function as the signaling molecules in plants responding to salt stresses. The present study presents a signaling network involving H2S and H2O2 in salt resistance pathway of the Arabidopsis root. Arabidopsis roots were sensitive to 100 mM NaCl treatment, which displayed a great increase in electrolyte leakage (EL) and Na(+)/K(+) ratio under salt stress. The treatment of H2S donors sodium hydrosulfide (NaHS) enhanced the salt tolerance by maintaining a lower Na(+)/K(+) ratio. In addition, the inhibition of root growth under salt stress was removed by H2S. Further studies indicated that H2O2 was involved in H2S-induced salt tolerance pathway. H2S induced the production of the endogenous H2O2 via regulating the activities of glucose-6-phosphate dehydrogenase (G6PDH) and plasma membrane (PM) NADPH oxidase, with the treatment with dimethylthiourea (DMTU, an ROS scavenger), diphenylene iodonium (DPI, a PM NADPH oxidase inhibitor), or glycerol (G6PDH inhibitor) removing the effect of H2S. Treatment with amiloride (an inhibitor of PM Na(+)/H(+) antiporter) and vanadate (an inhibitor of PM H(+)-ATPase) also inhibited the activity of H2S on Na(+)/K(+) ratio. Through an analysis of quantitative real-time polymerase chain reaction and Western blot, we found that H2S promoted the genes expression and the phosphorylation level of PM H(+)-ATPase and Na(+)/H(+) antiporter protein level. However, when the endogenous H2O2 level was inhibited by DPI or DMTU, the effect of H2S on the PM Na(+)/H(+) antiporter system was removed. Taken together, H2S maintains ion homeostasis in the H2O2-dependent manner in salt-stress Arabidopsis root.