The presence of potentially toxic elements and compounds in foodstuffs is of intense public interest, and so food producers as well as regulators require rapid, reliable screening methods to accurately determine the levels of such contaminants in food and drink. In the case of arsenic (As), concentration levels in foods may be increased through the historical use of As-containing agrochemicals ...

The phosphotransacetylase from Clostridium acidiurici has two properties not observed for this enzyme in other bacteria: (i) it requires a divalent metal for activity, and (ii) it is not subject to uncoupling by arsenate. The enzyme has been obtained in highly purified form, with a specific activity 500-fold higher than crude extracts. Ferrous or manganous ions are required for maximal activity...

Niu-Huang-Jie-Du Pian (NHJD) is a widely used traditional Chinese medicine containing realgar (As4S4). Realgar has been included in many traditional medicines, but is often taken as arsenite for risk assessment. To evaluate true risk of realgar and realgar-containing NHJD, their toxicity was compared with common arsenicals. In cultured cells, the LC50 for NHJD (1200 μM) and realgar (2000 μM) wa...

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...

Arsenic toxicity has been studied for a long time due to its effects in humans. Although epidemiological studies have demonstrated multiple effects in human physiology, there are many open questions about the cellular targets and the mechanisms of response to arsenic. Using the fission yeast Schizosaccharomyces pombe as model system, we have been able to demonstrate a strong activation of the M...

Arsenic is a toxic pollutant present in the environment that causes serious health issues. Phytoremediation is one potential solution to mitigate arsenic contamination in either soil or water. Two main forms of arsenic exist in the environment, arsenite, [As(III)], and arsenate, [As(V)]. In plant mechanisms, arsenate reductase reduces arsenate to arsenite with the help of thioredoxins or glutar...

River Mandovi and Zuari (west coast of India) are flowing through iron and manganese mining areas and are heavily used for iron and manganese ore transport. This region generates 25-30 million tons of mining rejects per year. The iron ore of Mandovi-Zuari catchments area has approximately 50.04 μg/g of arsenic and partial dissolution of the mining rejects could enrich the dissolved arsenic in e...

Transport of 5-methyltetrahydropteroylglutamic acid (5CH,-H,PteGlu) was studied in hepatocytes isolated from rat liver by enzymatic dispersion. The hepatocytes maintained gradients for sodium and potassium ions (I Na+l = 28.1 meql liter and I K+I = 133 meqlliter of cell water) during 90 min of incubation. Uptake of 5-CH,,-H,PteGlu was found to be a complex process. At low concentrations of subs...

A better understanding of the resistance mechanisms used by the cyanobacterium Synechococcus sp. PCC 7942 could guide attempts to develop this organism for use in bioremediation. This bacterium exhibits extraordinary resistance to arsenate. Possible mechanisms include exclusion from the cell, intraand extra-cellular binding, and potential interactions with proteins such as metallothioneins, whi...

The rate constants for in situ arsenic redox transformations in the surface waters of a eutrophic lake were estimated from observed horizontal heterogeneity in the arsenic species concentrations in the epilimnion of the Upper Mystic Lake. The smallest rate constants necessary to explain the observed horizontal heterogeneities were 10 times higher than rate constants estimated from monthly profi...