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 Rainbow colors reveal cell history: Uncovering β-cell heterogeneity
22.09.2017 | DFG-Forschungszentrum für Regenerative Therapien TU Dresden

nachricht The pyrenoid is a carbon-fixing liquid droplet
22.09.2017 | Max-Planck-Institut für Biochemie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Rainbow colors reveal cell history: Uncovering β-cell heterogeneity

22.09.2017 | Life Sciences

Penn first in world to treat patient with new radiation technology

22.09.2017 | Medical Engineering

Calculating quietness

22.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>