Featured Research

from universities, journals, and other organizations

Researchers Uncover E. Coli's Defense Mechanism

October 5, 2005
Georgia Institute of Technology
Researchers have uncovered a mechanism with which disease-causing bacteria may thwart the body's natural defense responses. The discovery of how iron is key to nitric oxide reduction could ultimately lead to the development of more effective antibiotics.

Researchers have discovered that iron is key to the defense mechanism of E. coli (shown here as a pathogenic Escherichia coli O157:H7 strain). Image courtesy of CDC/Elizabeth H. White, M.S.

“Nitricoxide is produced by the body to fight infections. We discovered amechanism that allows bacterial cells to detect nitric oxide and turnit into something that’s harmless to the cell,” said Stephen Spiro,associate professor in the School of Biology at Georgia Tech.

Spiro,along with colleagues Benoξt D'Autrιauz, Nicholas Tucker and Ray Dixonfrom the John Innes Centre, studied a non-pathogenic strain ofEscherichia coli, which is very closely related to salmonella bacteria.

Thepathogenic forms of E. coli and salmonella are usually transmitted tohumans through undercooked meat, unwashed vegetables and crosscontamination from surfaces on which these foods were prepared.Infections from either of these organisms can cause diarrhea, abdominalcramps and sometimes more serious illnesses that requirehospitalization. E.coli doesn’t respond well to antibiotics, whilesalmonella has developed several drug-resistant strains. Learning howthe bacteria handle the body’s immune response is the first step indeveloping more effective medicines.

Spiro and colleagues focusedtheir study on the NorR protein and the role it plays in reducing thelevels of nitric oxide. In response to nitric oxide, NorR binds to DNAin order to regulate expression of an enzyme that reduces the amount ofnitric oxide in the bacteria. Since nitric oxide binds to metals, theresearchers suspected that there might be a metal in the protein.

“Itturns out that the protein NorR contains a single molecule of iron,”said Spiro. “Our study found that the nitric oxide binds to the iron,which in turn activates the protein.”

Once activated, the proteincontrols expression of the norVW genes. These genes encode an enzymethat removes the nitric oxide, allowing the bacteria to fend off thebody’s defenses.

The discovery of this mechanism is just thefirst step in what Spiro hopes will be a line of research aimed atdisrupting the mechanism by which the bacteria rids itself of thepoisonous nitric oxide.

“If we can interfere with the mechanism, it could lead to better antibiotics and better treatments,” said Spiro.

The research was funded by a grant from the Biotechnology and Biological Sciences Research Council.

Story Source:

The above story is based on materials provided by Georgia Institute of Technology. Note: Materials may be edited for content and length.

Cite This Page:

Georgia Institute of Technology. "Researchers Uncover E. Coli's Defense Mechanism." ScienceDaily. ScienceDaily, 5 October 2005. <www.sciencedaily.com/releases/2005/10/051005075423.htm>.
Georgia Institute of Technology. (2005, October 5). Researchers Uncover E. Coli's Defense Mechanism. ScienceDaily. Retrieved July 22, 2014 from www.sciencedaily.com/releases/2005/10/051005075423.htm
Georgia Institute of Technology. "Researchers Uncover E. Coli's Defense Mechanism." ScienceDaily. www.sciencedaily.com/releases/2005/10/051005075423.htm (accessed July 22, 2014).

Share This

More Plants & Animals News

Tuesday, July 22, 2014

Featured Research

from universities, journals, and other organizations

Featured Videos

from AP, Reuters, AFP, and other news services

Michigan Plant's Goal: Flower and Die

Michigan Plant's Goal: Flower and Die

AP (July 22, 2014) — An 80-year-old agave plant, which is blooming for the first and only time at a University of Michigan conservatory, will die when it's done (July 22) Video provided by AP
Powered by NewsLook.com
San Diego Zoo Welcomes New, Rare Rhino Calf

San Diego Zoo Welcomes New, Rare Rhino Calf

Reuters - US Online Video (July 21, 2014) — An endangered black rhino baby is the newest resident at the San Diego Zoo. Sasha Salama reports. Video provided by Reuters
Powered by NewsLook.com
Shark Sightings a Big Catch for Cape Tourism

Shark Sightings a Big Catch for Cape Tourism

AP (July 21, 2014) — A rise in shark sightings along the shores of Chatham, Massachusetts is driving a surge of eager vacationers to the beach town looking to catch a glimpse of a great white. (July 21) Video provided by AP
Powered by NewsLook.com
$23.6 Billion Awarded To Widow In Smoking Lawsuit

$23.6 Billion Awarded To Widow In Smoking Lawsuit

Newsy (July 20, 2014) — Cynthia Robinson claims R.J. Reynolds Tobacco Company hid the health and addiction risks of its products, leading to the death of her husband in 1996. Video provided by Newsy
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.


Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News


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