Abstract:Turmeric is a member of the ginger family (Zingiberaceae), which is extensively used as a spice, food preservative and colouring material. Curcumin is a main bioactive natural compound derived from the rhizome of this plant. Curcumin can exist in several tautomeric forms, keto and enol. The keto form is more stable than enol form. Silyl ethers have proven to be versatile substrates for...

Washed cells of Enterobacter cloacae HO1 reduced hexavalent chromium (chromate: CrO4(2-) anaerobically. Chromate reductase activity was preferentially associated with the membrane fraction of the cells. Right-side-out membrane vesicles prepared from E. cloacae cells showed high chromate reductase activities when ascorbate-reduced phenazine methosulfate was added as an electron donor.

Chromate resistance of Pseudomonas fluorescens LB300, isolated from chromium-contaminated sediment in the upper Hudson River, was found to be plasmid specified. Loss of the plasmid (pLHB1) by spontaneous segregation or mitomycin C curing resulted in a simultaneous loss of chromate resistance. Subsequent transformation of such strains with purified pLHB1 plasmid DNA resulted in a simultaneous re...

The chromate efflux pump encoding gene chrASO was identified on the chromosome of Shewanella oneidensis MR1. Although chrASO is expressed without chromate, its expression level increases when Cr(VI) is added. When deleted, the resulting mutant ΔchrASO exhibits a chromate sensitive phenotype compared to that of the wild-type strain. Interestingly, heterologous expression of chrASO in E. coli con...

DISCLAIMER This report, prepared in cooperation with the University of Rhode Island Transportation Center, does not constitute a standard, specification, or regulation. The contents of this report reflect the views of the author(s) who is (are) responsible for the facts and the accuracy of the data presented herein. This document is disseminated under the sponsorship of the Department of Transp...

In Alcaligenes eutrophus CH34, determinants encoding inducible resistance to chromate (chr) and to cobalt and nickel (cnr) are located adjacent to each other on plasmid pMOL28. To develop metal-sensing bacterial strains, a cloned part of plasmid pMOL28, which contains both determinants, was mutated with Tn5-lacZ. The chr::lacZ fusions were specifically induced by chromium; cnr was induced best ...

The effects of thiol compounds (L-cysteine ethyl ester, 2,3-dimercaptosuccinic acid, or 2,3-dimercapto-1-propanesulfonic acid) on the toxicity induced by chromate (potassium dichromate) were investigated in HeLa cells and mice. Chromate-induced cytotoxicity evaluated by inhibition of cell growth and chromium content of the cells was diminished by all of the thiol compounds tested when the cells...

In this work, the WGS performance of a conventional Ni/CeO2 bulk catalyst is compared to that of a carbon-supported Ni-CeO2 catalyst. The carbon-supported sample resulted to be much more active than the bulk one. The higher activity of the Ni-CeO2/C catalyst is associated to its oxygen storage capacity, a parameter that strongly influences the WGS behavior. The stability of the carbon-supported...

Chromate is an established human carcinogen. There have been many studies of the reactivity of chromate aimed at improving understanding of chromate toxicity. In the present paper a number of conclusions of these studies are reviewed and considered in the light of new results obtained in our laboratories. A number of hypotheses are considered; it is concluded, however, that it is impossible to ...

An efficient and chemoselective cleavage of silyl ethers (primary, secondary and aromatic) by using catalytic quantities of trimethylsilyl bromide (TMSBr) in methanol is reported. A wide range of alkyl silyl ethers such as TBS, TIPS, and TBDPS can be chemoselectively cleaved in high yield in the presence of aryl silyl ethers. The deprotection of silyl esters was also achieved employing catalyti...