Amid recent reports of dangerous levels of arsenic being found in some baby rice products, scientists have found a protein in plants that could help to reduce the toxic content of crops grown in environments with high levels of this poisonous metal. Publishing in the open access journal BMC Biology, a team of Scandinavian researchers has revealed a set of plant proteins that channel arsenic in and out of cells.
Arsenic is acutely toxic and a highly potent carcinogen, but is widespread in the earth's crust and easily taken up and accumulated in crops. Contaminated water is the main source of arsenic poisoning, followed by ingestion of arsenic-rich food, especially rice that has been irrigated with arsenic-contaminated water. According to the WHO, arsenic has been found approaching or above guideline limits in drinking water in Argentina, Australia, Bangladesh, Chile, China, Hungary, India, Mexico, Peru, Thailand, and the US.
Until now, scientists have been unable to identify which proteins are responsible for letting arsenite, the form of arsenic that damages cellular proteins, into plant cells. Now Gerd Bienert and his colleagues from the University of Copehangen, Denmark and the University of Gothenburg, Sweden, are the first to show that a family of transporters, called nodulin26-like intrinsic protein (NIPs), can move arsenite across a plant cell membrane. NIPs are related to aquaglyceroporins found in microbes and mammalian cells and which have already been shown to function as arsenite channels in these other organisms.
Bienert's team put the plant genes coding for different NIP transporters into yeast cells in order to test the cells for arsenic sensitivity. The researchers found that the growth of yeast containing certain plant NIPs was suppressed when arsenite, one of the predominant forms of arsenic found in soil, was added to the mix. They showed that the arsenite was channelled by NIPs and accumulated inside the yeast cells. Furt
|Contact: Charlotte Webber|