APR 08, 2015 8:48 AM PDT

You Think Bacteria are "Loners"? Think Again.

WRITTEN BY: Robert Woodard
The Bacterium Bacillus subtilis taken with a Tecnai T-12 TEM.If you thought bacteria were "loners," molecular biologist Kevin Griffith of the University of Massachusetts Amherst has news for you: scientists now realize that bacteria exhibit social behavior within groups.

As Griffith explains: "Individual bacteria within a population communicate with members of the group through a process called quorum sensing, where chemical signals and extracellular peptides serve as the language for bacterial communication." It is not just "social" networking, he adds. Bacterial communities use quorum sensing to control a variety of biomedically relevant biological processes.

In a new paper in a recent early online edition of Molecular Microbiology, he and co-authors Kristina Boguslawski and Patrick Hill describe how they deciphered this bacterial communication to reveal new mechanisms of regulating gene expression in the model bacterium Bacillus subtilis.

"Research in my lab is devoted to deciphering these different bacterial languages, understanding how bacteria perceive these signals, and determining how bacteria use this information to regulate biological processes at the molecular level," says Griffith. "In this paper, we have expanded the range of biological processes known to be controlled by a plasmid-encoded quorum response pair known as Rap60-Phr60.

Using biochemical approaches, the authors found that Rap60 regulates the activity of two important transcription factors by "mechanisms never before observed for Rap proteins," says Griffith. "This work changes the way we think about these important regulatory proteins. The implications likely extend beyond Bacillus biology as they represent potential novel targets for the development of antibiotic and therapeutics in pathogenic bacteria."

In addition to providing fundamental knowledge about how this regulation occurs in a non-pathogenic bacterium like B. subtilis, understanding these pathways has the potential to provide new insight into how pathogenic bacteria regulate virulence factors and colonize hosts, which can have a profound impact on human health, he adds.

He explains, "Bacteria within a population secrete extracellular signals that provide the cue to coordinate biological processes as a group. Many pathogenic bacteria use these extracellular signals to regulate the production of antibiotics and virulence factors, the timing of which is important in disease."

Each species of bacteria has its own unique language, the authors say. In addition, there are "universal signals, analogous to Morse code, used for communication between different species of bacteria," says Griffith. "In microbial communities, bacteria within a similar group communicate with one another, while other groups are eavesdropping or even disrupting the others' communication. It is biological espionage. Bacteria that can communicate with one another and work together as a group will be more successful in competing for resources than individuals."

The researchers found, in addition to controlling the production of degradative enzymes, which was already known, that the Rap60 protein inhibits sporulation, genetic competence (the uptake of foreign DNA), and biofilm formation. Phr60 acts as an extracellular cell-cell signaling peptide that coordinates the activity of Rap60 with population density, says Griffith.

In the future, he adds, "We are currently looking at the role Rap60 and other Rap proteins play in regulating gene expression under a variety of different growth conditions. It is becoming increasingly clear that Rap proteins are more versatile than we originally believed in terms of the number of pathways they control and the range of different mechanisms used to regulate gene expression. In addition, we are expanding our investigations to better understand inter-species signaling between B. subtilis and other bacterial and eukaryotic microbes that have biomedical importance."

(Source: "New mechanisms of 'social networking' in bacteria," by Janet Lathrop, www.phys.org)
About the Author
You May Also Like
MAR 17, 2020
Genetics & Genomics
MAR 17, 2020
Targeting RNA With CRISPR
Researchers screened thousands of target molecules to find the most effective targets, and have made their data openly a ...
APR 01, 2020
Microbiology
APR 01, 2020
How Two Types of Tests for COVID-19 Work
There are a couple of different kinds of tests that researchers will be developing and clinicians will be using to disru ...
APR 02, 2020
Chemistry & Physics
APR 02, 2020
Improved management of nitrate pollution
Researchers have finally succeeded in improving the mechanisms available for the degradation of nitrate pollution. Scien ...
APR 22, 2020
Microbiology
APR 22, 2020
First COVID-19 Death Happened in the US Far Earlier Than We Thought
It was thought that the first death in the US from SARS-CoV-2 happened in Washington State in late February, but autopsi ...
MAY 11, 2020
Microbiology
MAY 11, 2020
Bacteria Can Tumble Their Way Out of Traps
We share the world with vast numbers of microbes, many of which are able to move around freely in the environment. Most, ...
JUN 01, 2020
Genetics & Genomics
JUN 01, 2020
Vaping Increases Oral Disease Risk After Only a Few Months
E-cigarettes have emerged as a healthier alternative to smoking, but many studies have suggested that vaping still poses ...
Loading Comments...