Internal cellular sensors make Salmonella dangerous: study

June 15, 2012 By Bill Hathaway, Yale University
Salmonella bacteria (in green) are engulfed by immune system cell called a macrophage. The direct threat from the immune cell activates genes that trigger the organism to become virulent and dangerous to the host.

(Phys.org) -- Salmonella becomes dangerously virulent only when molecular sensors within the organism sense changes in the environment, a team of researchers from the Yale School of Medicine and the Yale Microbial Diversity Institute report in the June 14 issue of the journal Nature.

Other probably possess analogous sensors to activate and cause maladies such as and tuberculosis, the authors suggest. This mechanism may present a novel target for drugs that can disarm bacteria’s ability to cause disease, said Eduardo A. Groisman, professor of microbial pathogenesis at the Yale School of Medicine and an investigator with the Howard Hughes Medical Institute.

“There will never be a world without because it exists in many, many animal reservoirs,” Groisman said. “So you can try to avoid getting Salmonella or learn how to fight it.  Hundreds of thousands of people die from Salmonella poisoning each year, and tens of millions of people are infected. It is a major public health issue.”

Groisman and Eun-Jin Lee of Yale investigated whether signals from outside the bacteria triggered one of its virulence genes. The researchers meticulously tracked the molecular chain reaction that occurs after Salmonella becomes engulfed by macrophages, immune system cells that respond to bacterial invaders. Salmonella then can reproduce rapidly, often overwhelming defenses of the host.

The Nature paper discovers that it is not the direct threat from the environment itself that triggers the virulence gene within the bacterium. Instead, changes in the level of acidity in Salmonella’s surroundings trigger an increase in levels of ATP, the energy currency of all cells. It is the change in ATP levels within the organism that activates virulence factors and enables Salmonella to survive within its host.

This internal sensor acts in concert with several other factors necessary before these bacteria can become virulent, Groisman said. Understanding all these processes should help scientists develop defenses against infectious diseases, he adds.

Explore further: Salmonella uses similar mechanism to infect plants and humans

Related Stories

Salmonella uses similar mechanism to infect plants and humans

September 13, 2011

In recent years, it has become clear that food poisoning due to Salmonella typhimurium can be contracted not only by uncooked eggs and meat but also through eating contaminated raw vegetables and fruit. So far, it was unclear ...

Salmonella: Trickier than we imagined

June 13, 2008

Salmonella is serving up a surprise not only for tomato lovers around the country but also for scientists who study the rod-shaped bacterium that causes misery for millions of people.

Recommended for you

Cells lacking nuclei struggle to move in 3-D environments

January 20, 2018

University of North Carolina Lineberger Comprehensive Cancer Center researchers have revealed new details of how the physical properties of the nucleus influence how cells can move around different environments - such as ...

Microbial communities demonstrate high turnover

January 19, 2018

When Mark Twain famously said "If you don't like the weather in New England, just wait a few minutes," he probably didn't anticipate MIT researchers would apply his remark to their microbial research. But a new study does ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.