However, when the bacteria contained the toxin-encoding virus, some were induced to produce the toxin and kill the Tetrahymena. This allowed the remaining bacteria to proliferate because there were fewer Tetrahymena eating them.
It appears that the presence of the Tetrahymena induces toxin release by activating what is called an SOS response in the bacteria, said Todd M. Hennessey, Ph.D., UB professor of biological sciences and Koudelkas co-author on the research.
There are many danger signals that can trigger this response and we are working on identifying the ones involved in this case.
And it has major implications for treating patients, Koudelka added.
When you give antibiotics to patients infected with the Shiga-toxin-producing bacteria, it may make them even sicker, he said. Thats because in the process of killing off the bacteria, the SOS response causes even more toxin to be released to do even more damage.
But interestingly, in the UB studies, some of the Tetrahymena exhibited resistance to the Shiga toxin.
If we can find out how that resistance develops, then we might be able to find a treatment method that would give human cells the ability to become resistant to the toxin, too, said Hennessey.
The fact that humans appear to be innocent bystanders in a microbial war between virus-containing bacteria and their predators plays a major role in developing ways to treat patients stricken with the toxin, the researchers said.
We have a very mammalian way of thinking about this and its wrong, said Koudelka. We are a very small part of the entire ecology of the planet and just because something can hurt us doesnt mean thats why its there.
|Contact: Ellen Goldbaum|
University at Buffalo