Just an innocuous pond dweller ?
Ever wondered why bother doing research on an innocuous pond dweller like Tetrahymena?
Consider the following story about Shiga based food poisoning, a serious disease that affects many people each year. This fascinating work on Tetrahymena may shed some light on possible more effective treatments for Shiga toxin poisoning. That’s the same toxin found in bagged spinach last year that was implicated in the deaths of 5 people and made hundreds more sick.
Dr. Todd Hennessey (some of you met him last summer – he was our guest lecturer at the first Tetrahymena teacher workshop) and his collaborators used Tetrahymena to study Shiga toxin toxicity by examining resistance to the toxin in Tetrahymena. Their work has provided “the most complete picture to date of the complex biological mechanisms of bacterial viruses infected with this toxin”.
It turns out that Tetrahymena normally munch quite happily on E. coli that do not carry the Shiga toxin virus, but bacteria carrying the virus with the gene for making the toxin did not make quite such a happy meal. The presence of the Tetrahymena triggered an SOS response in the bacteria and induced Shiga toxin release. This “danger response” may have big implications for treating human patients. It turns out that giving antibiotics to humans infected with bacteria that make Shiga toxin may make them even sicker. That’s because an SOS response similar to that induced by Tetrahymena causes the bacteria to release even more toxin, and that makes the infected person even worse!
One fascinating discovery is that some Tetrahymena exposed to Shiga producing bacteria actually developed a resistance to the toxin. If researchers can figure out how that resistance develops, a treatment that would make human cells capable of becoming resistant might be possible.
Humans may just be caught in the natural crossfire of an ancient microbial war.