How bacteria's in-built thermometer helps spread infection

Washington, May 21 (ANI): Scientists at the Helmholtz Centre for Infection Research (HZI) have for the first time shown how bacteria measure temperature, and thereby cause intestinal infection.

The HZI researchers at Braunschweig and the Braunschweig Technical University have found that bacteria of the Yersinia genus have a unique protein thermometer - the protein RovA - that helps them in the infection process. ovA is a multi-functional sensor that measures both the temperature of its host and the host's metabolic activity and nutrients.

If these are suitable for the survival of the bacteria, the RovA protein activates genes for the infection process to begin.

Yersinia is known for triggering various different diseases, one of the well-known diseases is the Yersinia pestis type which caused the Plague in medieval times, leading to the death of around a third of Europe's population.

The Yersinia enterocolitica and Yersinia pseudotuberculosis species cause an inflammation of the intestines following food poisoning.

The Yersinia bacteria contain invasin as a surface protein to help them penetrate the intestinal cells, leading to heavy bouts of diarrhoea.

Led by Petra Dersch, the researchers have now identified how the RovA protein plays a key role in the various stages of Yersinia infection.

The protein reads the temperature for the bacteria, on the basis of which it either contains the factors required for the infection to begin or else adapts to life within the host.

"The functioning of RovA in this way is unique among bacteria," said Dersch.

If inhabiting an environment of around 25 degree Celsius, the protein RovA ensures that the Yersinia bacteria form invasin as a surface protein, which ensures that the bacteria can penetrate the intestinal cells immediately upon reaching the 37 degree Celsius intestine via food.

The warm environment enables RovA to alter its form and de-activates the gene for invasin production.

Without invasin on their surface, the Yersinia bacteria are invisible to the body's immune system, thus making it possible for RovA to now activate other genes in the bacteria to adapt the Yersinia metabolism with that of the host.

"We have long been searching for the mechanisms which regulate RovA activity. It was therefore all the more surprising to discover that RovA controls various processes by acting as a thermometer and as such is self-regulating," said Dersch.

The results have been published in the current online edition of the PLoS Pathogens science magazine. (ANI)