The steady state extent of H+ uptake in illuminated chloroplasts can be observed routinely to be decreased by ADP in the presence of arsenate when these reagents are present at saturating concentrations. The failure of previous investigators to observe this phenomenon may be explained by the fact that suboptimal concentrations of ADP and especially arsenate were used. AT9 (or ADP) in the absenc...

Arsenic is a common contaminant in soils and water. It is well established that the fern Pteris vittata L. is an As hyperaccumulator and therefore has potential to phyroremediate As-polluted soils. Also, it is accepted that rhizosphere microflora play an enhancing role in plant uptake of metallic elements from soils. Studies showed that hydroponiclly grown P. Vittata accumulated arsenite more t...

Arsenic resistance is commonly clustered in ars operons in bacteria; main ars operon components encode an arsenate reductase, a membrane extrusion protein, and an As-sensitive transcription factor. In the As-resistant thermophile Thermus thermophilus HB27, genes encoding homologues of these proteins are interspersed in the chromosome. In this article, we show that two adjacent genes, TtsmtB, en...

Microbial metabolism contributes to degradation of organoarsenicals, where arsenic reductases (glutaredoxins) play pivotal role in bacterial resistance to arsenic. Ars operon studies have revealed reduction of arsenate As(V) to arsenite As(III) by respiratory-chainlinked reductase enzyme complexes. Although structure of some bacterial arsenate reductases has been solved but not attempted for Bi...

A pseudomonad (CRB5) isolated from a decommissioned wood preservation site reduced toxic chromate [Cr(VI)] to an insoluble Cr(III) precipitate under aerobic and anaerobic conditions. CRB5 tolerated up to 520 mg of Cr(VI) liter(-1) and reduced chromate in the presence of copper and arsenate. Under anaerobic conditions it also reduced Co(III) and U(VI), partially internalizing each metal. Metal p...

Desulfuribacillus alkaliarsenatis AHT28T is an obligately anaerobic, sulfur- and arsenate-reducing haloalkaliphile that was isolated from Russian soda lake sediments. Here, we present the 3.1-Mb draft genome sequence for this strain, consisting of 36 contigs with a G+C content of 37.5% and 2,978 protein-coding sequences.

The fate of the oxoanion arsenate in diverse systems is strongly affected by its adsorption on the surfaces of iron (oxyhydr)oxide minerals. Predicting this behavior in the environment requires an understanding of the mechanisms of arsenate adsorption. In this study, the binding site and adsorption geometry of arsenate on the hematite (012) surface is investigated. The structure and termination...

An anion-translocating ATPase has been identified as the product of the arsenical resistance operon of resistance plasmid R773. When expressed in Escherichia coli this ATP-driven oxyanion pump catalyzes extrusion of the oxyanions arsenite, antimonite and arsenate. Maintenance of a low intracellular concentration of oxyanion produces resistance to the toxic agents. The pump is composed of two po...

nanoparticles of manganese-dioxide synthesized by mechano-chemical reaction were used foras(iii) and as(v) sorption from water environment. the influence of a milling time of manganese-dioxide on sorption was examined with batch procedure. sorption as a function of contact time was investigated. kinetic of sorption, for both as(iii) and as(v), was fast. the equilibrium condition for milled sorb...