Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Social mobility: Study shows bacteria seek each other out

30.07.2003


A study by Princeton University scientists has shown that bacteria actively move around their environments to form social organizations. The researchers placed bacteria in minute mazes and found that they sought each other out using chemical signals.



Biologists have become increasingly aware of social interactions among bacteria, but previously believed that clusters formed only when bacteria randomly landed somewhere, then multiplied into dense populations. The discovery that they actively move into gatherings underscores the importance of bacterial interactions and could eventually lead to new drugs that disrupt the congregating behavior of harmful germs, said Jeffry Stock, a professor of molecular biology and co-author of the paper.

"It makes sense, but it’s surprising that it’s as pervasive as it now seems to be," said Stock.


The researchers observed the gathering behavior in E. coli as well as in V. harveyi, a marine bacteria that glows when it achieves a high-density population. They found that when placed in mazes the bacteria congregated in small rooms and dead-end pathways. Once clustered, the V. harveyi turned on the genes that make them glow.

Biologists had previously believed that bacteria’s ability to move and follow chemical signals - a process called chemotaxis - was primarily a means of dispersing and seeking food. The new study shows that chemotaxis may also be important for facilitating cooperative behavior.

The work was a collaboration between Stock’s lab in biology and that of Robert Austin, a professor of physics. Emil Yuzbashyan, a graduate student in Austin’s noticed unusual clumping when he put E. coli into microscopically small mazes made of silicone. Biologists in Stock’s lab supplied mutant strains of bacteria that lacked genes necessary for sensing chemical signals and chemotaxis. They found that bacteria themselves emit a key chemical attractant and that those lacking the gene for the receptor that senses that attractant did not cluster as normal bacteria did.

Disrupting chemotaxis could be a route to attacking biofilms, a common type of bacterial interaction in which they form a colony that is resistant to antibiotic drugs and chemicals, the researchers said. Biofilms pose a common danger to patients receiving medical implants and cause trouble for ships that develop biofilms on their hulls.

Clustering also allows bacteria to perform a coordinated activity called quorum sensing in which they turn on certain genes only when they sense that they are part of a dense population. Some disease-causing bacteria are believed to rely on quorum sensing in mounting a successful infection. The V. harveyi in the experiment glowed as a result of quorum sensing after they gathered into a dense population.

"Our paper points out that you don’t necessarily need growth to achieve quorum sensing," said Peter Wolanin, a postdoctoral researcher in Stock’s lab. "The bacteria can actively seek each other out to engage in collective social behavior."

The behavior observed in the experiment also may have been a survival mechanism, said Sungsu Park, a postdoctoral researcher in Austin’s lab and first author of the paper. The research was conducted with the bacteria in a nutrient-depleted environment that resembles the natural conditions for bacteria much of the time. "The bacteria are chasing amino acids released from their own cell bodies during starvation conditions," said Park. "So by getting close to each other they have a better chance of getting nutrients."

The researchers also have developed a mathematical model that simulates the bacterial congregation, said Park. They plan further research to investigate the relation between bacterial behavior and the size and geometry of their physical environment.

| Princeton University
Further information:
http://www.princeton.edu

More articles from Life Sciences:

nachricht Nerves control the body’s bacterial community
26.09.2017 | Christian-Albrechts-Universität zu Kiel

nachricht Ageless ears? Elderly barn owls do not become hard of hearing
26.09.2017 | Carl von Ossietzky-Universität Oldenburg

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 fastest light-driven current source

Controlling electronic current is essential to modern electronics, as data and signals are transferred by streams of electrons which are controlled at high speed. Demands on transmission speeds are also increasing as technology develops. Scientists from the Chair of Laser Physics and the Chair of Applied Physics at Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) have succeeded in switching on a current with a desired direction in graphene using a single laser pulse within a femtosecond ¬¬ – a femtosecond corresponds to the millionth part of a billionth of a second. This is more than a thousand times faster compared to the most efficient transistors today.

Graphene is up to the job

Im Focus: LaserTAB: More efficient and precise contacts thanks to human-robot collaboration

At the productronica trade fair in Munich this November, the Fraunhofer Institute for Laser Technology ILT will be presenting Laser-Based Tape-Automated Bonding, LaserTAB for short. The experts from Aachen will be demonstrating how new battery cells and power electronics can be micro-welded more efficiently and precisely than ever before thanks to new optics and robot support.

Fraunhofer ILT from Aachen relies on a clever combination of robotics and a laser scanner with new optics as well as process monitoring, which it has developed...

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...

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

Nerves control the body’s bacterial community

26.09.2017 | Life Sciences

Four elements make 2-D optical platform

26.09.2017 | Physics and Astronomy

Goodbye, login. Hello, heart scan

26.09.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>