Featured Research

from universities, journals, and other organizations

Colonies of bacteria fight for resources with lethal protein

Date:
March 28, 2010
Source:
University of California - San Diego
Summary:
Rival colonies of bacteria can produce a lethal chemical that keeps competitors at bay, scientists report this week. By halting the growth of nearby colonies and even killing some of the cells, groups of bacteria preserve scarce resources for themselves, even when the encroaching colony is closely related.

Poisons are unleashed when colonies of bacteria get too close create a toxic "no-man's land" in between.
Credit: Eshel Ben-Jacob

Rival colonies of bacteria can produce a lethal chemical that keeps competitors at bay, scientists report. By halting the growth of nearby colonies and even killing some of the cells, groups of bacteria preserve scarce resources for themselves, even when the encroaching colony is closely related.

"It supports the notion that each colony is a superorganism, a multicellular organism with it's own identity," said Eshel Ben-Jacob, an adjunct senior scientist at UC San Diego's Center for Theoretical Biological Physics and professor of physics at Tel Aviv University. Ben-Jacob and lead author Avraham Be'er of the University of Texas, Austin, and other colleagues at these institutions report their discovery in the early online edition of the Proceedings of the National Academy of Sciences.

Alone in a dish, colonies of the bacterium Paenibacillus dendritiformis will send branches of cells in all directions. But when forced to share a plate of limited nutrients with another colony, the branching patterns of both colonies become lopsided, leaving a space between the two.

It's not a lack of food that halts the growth. The researchers found nutrients in the gap, but they also found a protein there that wasn't present elsewhere on the dish. When they dabbed a bit of the purified protein on a fresh dish inoculated with P. dendritiformis, the bacteria formed a lopsided colony that shied away from the spot. And the cells at the edge of the colony closest to the suspect protein were dead.

They named the protein "sibling lethal factor," for its ability to kill even closely related colonies derived from a single original colony, and identified its gene. But the gene made a protein that was too large, heavier that the lethal factor by two-thirds and harmless. They concluded that some other factor must be in play.

Rather than guess, or poke about experimentally to figure out what was going on, Ben-Jacob and his colleagues created a model to guide their thinking.

"In physics, we use models to make predictions," Ben-Jacob said, noting that biological models often present what is already understood. The model told them that they should be looking for something that would prune the full-size factor to its smaller lethal form as the colonies began to compete, a factor that might be harmless or even helpful until it reached a certain threshold.

P. dendritiformis also secretes a protein called subtilisin, which promotes growth, except in high concentrations. Subtilisin, which was already known and is available commercially, clipped the full-sized protein to the size of that found between competing colonies. This smaller piece slices the bacteria cells open and spills their contents into the medium, they found.

"Very often, you discover that in order to explain what's going on, you need to imagine mechanisms that are beyond what the biologists have specifically discovered about the system," said Herbert Levine, a physics professor at UC San Diego who co-directs the Center for Theoretical Biological Physics, but was not involved in this study. "In this work, they've succeeded in taking the next step," he said. "They were able find the chemical messenger that is actually playing the role they hypothesized."


Story Source:

The above story is based on materials provided by University of California - San Diego. The original article was written by Susan Brown. Note: Materials may be edited for content and length.


Journal Reference:

  1. A. Be'er, G. Ariel, O. Kalisman, Y. Helman, A. Sirota-Madi, H.P. Zhang, E.-L. Florin, S. M. Payne, E. Ben-Jacob, H. L. Swinney. Lethal protein produced in response to competition between sibling bacterial colonies. Proceedings of the National Academy of Sciences, 2010; DOI: 10.1073/pnas.1001062107

Cite This Page:

University of California - San Diego. "Colonies of bacteria fight for resources with lethal protein." ScienceDaily. ScienceDaily, 28 March 2010. <www.sciencedaily.com/releases/2010/03/100324094717.htm>.
University of California - San Diego. (2010, March 28). Colonies of bacteria fight for resources with lethal protein. ScienceDaily. Retrieved August 1, 2014 from www.sciencedaily.com/releases/2010/03/100324094717.htm
University of California - San Diego. "Colonies of bacteria fight for resources with lethal protein." ScienceDaily. www.sciencedaily.com/releases/2010/03/100324094717.htm (accessed August 1, 2014).

Share This




More Plants & Animals News

Friday, August 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Visitors Feel Part of the Pack at Wolf Preserve

Visitors Feel Part of the Pack at Wolf Preserve

AP (July 31, 2014) Seacrest Wolf Preserve on the northern Florida panhandle allows more than 10,000 visitors each year to get up close and personal with Arctic and British Columbian Wolves. (July 31) Video provided by AP
Powered by NewsLook.com
Florida Panther Rebound Upsets Ranchers

Florida Panther Rebound Upsets Ranchers

AP (July 31, 2014) With Florida's panther population rebounding, some ranchers complain the protected predators are once again killing their calves. (July 31) Video provided by AP
Powered by NewsLook.com
Dangerous Bacteria Kills One in Florida

Dangerous Bacteria Kills One in Florida

AP (July 31, 2014) Sarasota County, Florida health officials have issued a warning against eating raw oysters and exposing open wounds to coastal and inland waters after a dangerous bacteria killed one person and made another sick. (July 31) Video provided by AP
Powered by NewsLook.com
Raw: Thousands Flocking to German Crop Circle

Raw: Thousands Flocking to German Crop Circle

AP (July 30, 2014) Thousands of people are trekking to a Bavarian farmer's field to check out a mysterious set of crop circles. (July 30) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins