PITTSBURGHCarnegie Mellon University researchers have discovered that an element commonly found in nature might provide a way to neutralize the potentially lethal effects of a compound known as Shiga toxin. New results published in the Jan. 20 issue of Science by Carnegie Mellon biologists Adam Linstedt and Somshuvra Mukhopadhyay show that manganese completely protects against Shiga toxicosis in animal models.
Produced by certain bacteria, including Shigella and some strains of E. coli, Shiga toxin can cause symptoms ranging from mild intestinal disease to kidney failure. The findings could pave the way for future research aimed at creating an inexpensive treatment for infections caused by bacteria that produce the lethal Shiga toxin. Currently there is no treatment for such infections that afflict more than 150 million people each year, resulting in more than one million deaths worldwide.
Such infections are common in developing countries where it causes waterborne epidemics. It can be particularly deadly, especially in children, as it causes dysentery and severe hemorrhagic diarrhea, which cannot be adequately treated in areas without access to clean water. In developed countries, Shiga toxicosis is most common during foodborne outbreaks like the widespread E. coli outbreak this past summer in Germany and Western Europe, where more than 3,700 people were infected and 45 died.
After entering the body, Shiga toxin is secreted by the infecting bacteria. It then attaches itself to a surface receptor on a cell's plasma membrane and enters the cell through a process called endocytosis. Normally, when a harmful substance enters a cell in this way, it's wrapped in a package called an endosome and sent directly to the cell's lysosome where it is degraded and discarded.
"That's exactly the process that Shiga toxin avoids. It would be neutralized if it were to get degraded, so it had to find some way t
|Contact: Jocelyn Duffy|
Carnegie Mellon University