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.

Mechanism insight into rapid photocatalytic disinfection of Salmonella based on vanadate QDs-interspersed g-C3N4 heterostructures

Abstract: Photocatalytic disinfection, which is a readily reliable method in most climates, holds great promise to significantly reduce the microbial contamination in modern industry. Here we report that vanadate quantum dots-interspersed graphitic carbon nitride (vanadate QDs/g-C3N4) can achieve efficient inactivation of Salmonella by harvesting a substantial visible light. Detailed characterization through SEM-EDS, TEM, XRD, FT-IR, and XPS confirmed the formation of the composites. Owing to the efficient reactive oxygen species (ROS) production between vanadate QDs and g-C3N4, the bactericidal efficiency of AgVO3 QDs/g-C3N4 could reach 96.4% toward Salmonella in a concentration of 0.75 mg/mL after 10 min visible-light illumination. More importantly, scavenger experiments of different reactive species proved that the photoinduced electron generated at the oxidation site of AgVO3/g-C3N4 play a major role as oxidative species. Fluorescent-based cell live/dead test and membrane potentials were applied to demonstrate the integrity of cell membranes. Furthermore, the SEM technology, PCR and BCA protein assay were employed to verify the bacterial decomposition as well as leakage of bacterial cell contents toward Salmonella. Sterilization experiments of Staphylococcus aureus revealed that our composites have broad spectrum antimicrobial activity for both Gram-negative and Gram-positive bacteria under visible light. The results showed that the generation of high ROS could attack the bacterial cells membrane, and ultimately disrupt the cell metabolism through bacterial contents, which provided a feasible method for eliminating the microbial contaminated water.

Insulin-like effect of vanadyl ion on streptozotocin-induced diabetic rats.

Abstract: Recent studies have indicated that the blood glucose level of rats with streptozotocin (STZ)-induced diabetes (type 1) is normalized without an increase in the plasma insulin level by administration of sodium orthovanadate in the drinking water. The mechanism of this insulin-like effect of vanadate is unknown. In this study, we investigated whether vanadyl ion, which is less toxic than vanadate to rats, also has an insulin-like effect in rats with STZ-induced diabetes. When rats with STZ-induced diabetes were given a daily i.p. injection of vanadyl sulphate (9.3 and 4.6 mg vanadium/kg body weight), their blood glucose level decreased from about 22.2 to about 7.2 mmol glucose/l within 2 days and remained low for at least 12 weeks. This treatment did not affect their low plasma insulin level. Quantitative electron spin resonance (ESR) spectrometry showed that most of the vanadium (about 90%) in their tissues was present as a vanadyl form (VO2+). ESR analysis also showed that the vanadyl ion in tissues was bound endogenously with four oxygen ligands from either water or oxyamino acid residues in proteins. Vanadyl sulphate accelerated glucose incorporation into adipocytes of rats, suggesting that the action of vanadyl ion is peripheral. Interestingly, vanadyl sulphate at a high concentration (about 10 mmol/l) was more effective than insulin in enhancing glucose uptake. This study demonstrated that: (1) vanadyl sulphate (+4 oxidation state), like vanadate ion, normalizes the blood glucose levels of rats with STZ-induced diabetes; (2) the action of vanadyl ion is peripheral; and (3) the active form of vanadium for an insulin-like effect may be a vanadyl form, not vanadate.

H-pumping driven by the vanadate-sensitive ATPase in membrane vesicles from corn roots.

Abstract: The initial rate of quenching of quinacrine fluorescence was used to monitor Mg:ATP-dependent H+-pumping in membrane vesicles from corn (Zea mays L. cv WF9 × MO17) roots and obtain a preparation in which vanadate-sensitive H+-pumping could be observed. Separation of membranes on a linear sucrose density gradient resulted in two distinct peaks of H+-pumping activity: a major one, at density 1.11 grams per cubic centimeter, was sensitive to NO3− and resistant to vanadate, while a minor one, at density 1.17 grams per cubic centimeter, was substantially resistant to NO3− and sensitive to vanadate. A membrane fraction enriched in the vanadate-sensitive H+-pump could be obtained by washing microsomes prepared in the presence of 10% glycerol with 0.25 molar KI. The kinetics of inhibition of H+-pumping by vanadate in this membrane preparation indicated that most of the H+-pumping activity in this fraction is sensitive to inhibition by vanadate, 50% inhibition being reached at about 60 micromolar vanadate. This value is fairly close to that observed for inhibition by vanadate of the ATPase activity in similar experimental conditions (40 micromolar). The inhibitor sensitivity, divalent cation dependence, pH optimum (6.5), and Km for ATP (0.7 millimolar) of the H+-pumping activity match quite closely those reported for the plasma membrane ATPase of corn roots and other plant materials.