Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Small talk – The gabfest of microbial communication

30.04.2003


ONR-sponsored Bonnie Bassler looks at bacterial communication

She thinks they’re everywhere. What’s more, she thinks they talk to each other.
But don’t snicker…ONR-sponsored Bonnie Bassler won a MacArthur Foundation ’genius award’ last year for her research on how some of the most deadly microbes we know – cholera, plague, TB, just to mention a few – communicate surprisingly well.


In her Princeton Lab, Bassler (and the rest of the microbiology community) calls it ’quorum sensing.’ When microbes sense that there’s more than just a few of them around (i.e., increases in cell population density), a sort of gabfest starts, and this can lead to the production of toxins that make us very, very sick.

Microscopic organisms must rely on simple, yet complex (depending on how you look at it) means of communication. "Quorum sensing" was first discovered in two bacteria in the belly of the cuttlefish: Vibrio harveyi and Vibrio fischeri. These fellows emit light in response to increases in cell population density – they release and detect hormone-like molecules called autoinducers that accumulate in the surrounding aquatic environment as the bacterial cell density increases.

Working with Vibrio harveyi and Vibrio fischeri Bassler and her colleagues discovered that bacteria express a gene called LuxI, which results in the release of special chemicals she calls autoinducers (AI-1) which, in turn, bind to proteins called LuxR on other bacteria nearby. Once the LuxR is activated, a multitude of cellular effects, varying by species, is performed. This is especially useful to bacteria in sensing the size of their colony. Each bacterium constantly emits AI-1, as the number of individuals in a colony grows, so does the amount of AI-1 surrounding them. Once the colony reaches a certain size, a quorum, the amount of LuxI is sufficient to trigger cellular effects. Scores of bacteria species use this quorum sensing every day.

But why would bacteria care how many others are around them? Bacteria are the biggest biomass on the planet, and in order for them to be as successful as they are, they must work together for the good of the colony. Each bacterium is not a ’lone soldier’ so to speak, rather it waits until a sufficient number of others are around to begin producing toxins, or emitting light, etc. "Bacteria can talk to each other," Bassler says. "They take a roll call and the language is LuxI/LuxR."

Bassler’s research is important in the fight against virulent strains of bacteria. Her team’s current work is to find a way to disrupt this LuxI/LuxR language so the bacteria are deafened to the calls of their compatriots. Bassler and colleagues recently showed that cholera bacteria use quorum sensing to regulate their virulence.

"If a bacterium thinks it is alone in the world, it won’t produce the toxins which make us sick, or, for that matter, make biofilms which lead to ship hull fouling" says ONR sponsor Dr. Linda Chrisey. It’s only when many of them get together, and decide to "turn on", that the bacteria become a problem. "Since a disruption-type of therapy wouldn’t kill the bacteria, resistance to these new drugs would be slow to develop. This research has enormous potential for rapid, accurate pathogen sensing and novel antibiotic strategies."

Harmless bacteria can also be used to sense lethal strains. V. harveyi, which uses the LuxI/LuxR language to decide when to glow, can sense LuxI from other harmful species. "These guys can sense the ’who’s who’ of pathogenic bacteria, like anthrax, staph, strep, E. coli, and salmonella," Bassler says. "When V. harveyi senses the AI from other species, it glows brilliantly. In fact, many diverse bacterial functions such as virulence factor production, conjugative DNA transfer, symbiosis, and antibiotic production are now known to be controlled by quorum sensing."

Ah… spoken like a true genius.

Ed Walsh | EurekAlert!
Further information:
http://www.onr.navy.mil/

More articles from Life Sciences:

nachricht High-Speed Locomotion Neurons Found in the Brainstem
24.10.2017 | Universität Basel

nachricht Antibiotic resistance: a strain of multidrug-resistant Escherichia coli is on the rise
24.10.2017 | Deutsches Zentrum für Infektionsforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Salmonella as a tumour medication

HZI researchers developed a bacterial strain that can be used in cancer therapy

Salmonellae are dangerous pathogens that enter the body via contaminated food and can cause severe infections. But these bacteria are also known to target...

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

3rd Symposium on Driving Simulation

23.10.2017 | Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

 
Latest News

Single nanoparticle mapping paves the way for better nanotechnology

24.10.2017 | Physics and Astronomy

A quantum spin liquid

24.10.2017 | Physics and Astronomy

Antibiotic resistance: a strain of multidrug-resistant Escherichia coli is on the rise

24.10.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>