Microbiota-dependent in vivo biotransformation, accumulation, and excretion of arsenic from arsenobetaine-rich diet.

Arsenobetaine (AB), a major organic arsenic (As) species in seafood, is regarded as safe by current regulatory assessments due to low toxicity and rapid unmodified urinary excretion. This notion has been challenged by reports of AB metabolism by intestinal bacteria in vitro and more recent evidence of in vivo AB metabolism in mice. However, these studies did not establish the causal role of intestinal bacteria in AB transformation in vivo.

Increasing temperature and flooding enhance arsenic release and biotransformations in Swiss soils.

Reductive dissolution is one of the main causes for arsenic (As) mobilisation in flooded soils while biomethylation and biovolatilisation are two microbial mechanisms that greatly influence the mobility and toxicity of As. Climate change results in more extreme weather events such as flooding and higher temperatures, potentially leading to an increase in As release and biotransformations. Here, we investigated the effects of flooding and temperature on As release, biomethylation and biovolatilisation from As-rich soils with different pH and source of As (one acidic and anthropogenic (Salanfe) and one neutral and geogenic (Liesberg)).

The Need to Unravel Arsenolipid Transformations in Humans.

The main source of arsenic exposure to humans worldwide is the diet, in particular, drinking water, rice, and seafood. Although arsenic is often considered toxic, it can exist in food as more than 300 chemical species with different toxicities. This diversity makes it difficult for food safety and health authorities to regulate arsenic levels in food, which are currently based on a few arsenic species.

Evaluation of the ability of arsenic species to traverse cell membranes by simple diffusion using octanol-water and liposome-water partition coefficients.

Arsenic metabolism in living organisms is dependent on the ability of different arsenic species to traverse biological membranes. Simple diffusion provides an alternative influx and efflux route to mediated transport mechanisms that can increase the amount of arsenic available for metabolism in cells. Using octanol-water and liposome-water partition coefficients, the ability of arsenous acid, arsenate, methylarsonate, dimethylarsinate, thio-methylarsonate, thio-dimethylarsinic acid, arsenotriglutathione and monomethylarsonic diglutathione to diffuse through the lipid bilayer of cell membranes was investigated.

Bioaccessibility and degradation of naturally occurring arsenic species from food in the human gastrointestinal tract.

Humans are exposed to organic arsenic species through their diet and therefore, are susceptible to arsenic toxicity. Investigating the transformations occurring in the gastrointestinal tract will influence which arsenic species to focus on when studying metabolism in cells. Using a physiologically based extraction test, the bioaccessibility of arsenic species was determined after the simulated gastrointestinal digestion of rice, seaweed and fish.