Phylogenetic analysis indicates that microbial arsenic metabolism is ancient and probably extends back to the primordial Earth. In microbial biofilms growing on the rock surfaces of anoxic brine pools fed by hot springs containing arsenite and sulfide at high concentrations, we discovered light-dependent oxidation of arsenite [As(III)] to arsenate [As(V)] occurring under anoxic conditions. The ...

Rice (Oryza sativa L.) is the most important crop all over the world. It is considered the main 19 food of 50% of the world population especially in Egypt. However, rice not only accumulates some of 20 heavy metals such as cadmium but also accumulate arsenate (As). Arsenic contamination in water and 21 food resulted in many implications for millions of people leading cancer. For that reason, th...

These three component inorganic ion-exchanger was synthesized under different condition. The most thermal and chemical properties of this material is prepared by intermixing solutions of sodium molybdate (0.1 M), sodium arsenate (0.1 M) and antimony(III) chloride (0.1 M) solution in different volume ratios at pH-1. The Ion-exchange capacity of all the samples was determined by column process. T...

The authors presented their data from atomic absorption tests, stating that the cements released less than 0.0007 ppm of arsenic after a week of soaking in weakly acidic solution. That is, the cements released 0.7 ppb from their worst sample. My first comment is on the atomic absorption technique for arsenic. According to the EPA method 7062 for detection of arsenic by atomic absorption using s...

Escherichia coli cells treated with arsenate cannot tumble. The relationship between cellular adenosine 5'-triphosphate (ATP) level and the ability to tumble has been studied. (i) Cells incubated with arsenate completely lost their tumbling ability, and the cellular ATP level was decreased to less than 0.3 nmol/mg of protein. (ii) Incubation with 10 mM arsenate-1 mM phosphate reduced the cellul...

An arsenite-oxidizing Hydrogenobaculum strain was isolated from a geothermal spring in Yellowstone National Park, Wyo., that was previously shown to contain microbial populations engaged in arsenite oxidation. The isolate was sensitive to both arsenite and arsenate and behaved as an obligate chemolithoautotroph that used H(2) as its sole energy source and had an optimum temperature of 55 to 60 ...

The present study aimed to investigate the effects of root surface iron plaque on the uptake kinetics of arsenite and arsenate by excised roots of rice (Oryza sativa) seedlings. The results demonstrated that the presence of iron plaque enhanced arsenite and decreased arsenate uptake. Arsenite and arsenate uptake kinetics were adequately fitted by the Michaelis-Menten function in the absence of ...

We use spatially resolved high-resolution spectra of the 5890 and 5896 A sodium D lines in the nuclear regions of comet Hale-Bopp to determine the sources of cometary sodium. Comparison of the data to a Monte Carlo model of sodium dynamics suggests that the intensities and velocities of sodium in Hale-Bopp can be explained if 55% of the observed sodium is produced at the nucleus, the remaining ...

Arsenate is a major toxic constituent in arsenic-contaminated water supplies. Saccharomyces cerevisiae was engineered as a potential biosorbent for enhanced arsenate accumulation. The phosphate transporter, Pho84p, known to import arsenate, was overexpressed using a 2μ-based vector carrying PHO84 under the control of the late-phase ADH2 promoter. Arsenate uptake was then evaluated using a resti...