Deadly and damaging toxins that allow anthrax to cause disease and death in mammals have similar toxic effects in fruit flies, as per a research studyconducted by biologists at the University of California, San Diego.

Their findings, which appear this week in an early online edition of the journal Proceedings of the National Academy of Sciences, show that fruit flies can be used to study the link between the biochemical activities and physiological effects of anthrax toxins.

Learning how these toxins attack developing and adult tissues is important because it can help researchers understand how they function at the molecular level and may lead to new therapeutic strategies for neutralizing their effects in humans.

Annabel Guichard, a biologist at UCSD and lead author of the study, tracked the ways that two active anthrax toxins, known as lethal factor, or LF, and edema factor, EF, cause cellular damage and death in the fruit fly Drosophila melanogaster. These toxins are mandatory for the anthrax bacterium Bacillus anthracis to evade the host immune system and cause disease.

Using a combination of biochemical, genetic and cell biological approaches, the biologists tested whether or not the anthrax toxins were active in living Drosophila and, if so, whether they acted in the same way as they do in humans. The biologists found that anthrax toxins do alter the same signaling pathways used for cell communication in fruit flies and humans.

"Drosophila is an excellent tool to understand the effect of a toxin on its host and to determine the molecular mechanism underlying its toxicity, because the fly system is already so well characterized," Guichard said. "We knew how anthrax toxins acted on human cells, but this study is the first to show that these toxins are active in fruit flies, suggesting that this fast breeding laboratory animal could also be used to determine the function of a variety of bacterial and viral pathogenic factors."

Anthrax bacterium secretes three toxins, including LF and EF, and is only known to infect mammals. Because fruit flies lack components mandatory for toxin entry into cells, they cannot actually contract the anthrax disease. However, the study finds that fruit flies can be used to test the effects of a single virulence factor, such as the LF or EF toxins, on signaling pathways shared by flies and humans.

By Carina Stanton.