Featured Research

from universities, journals, and other organizations

Evolution Of Virulence Regulation In Staphylococcus Aureus

Date:
October 18, 2008
Source:
Cell Press
Summary:
Scientists have gained insight into the complex mechanisms that control bacterial pathogenesis and, as a result, have developed new theories about how independent mechanisms may have become intertwined during evolution. The research may lead to strategies for developing more effective therapeutics against the human pathogen responsible for most of the antibiotic-resistant infections contracted in the community.

Scientists have gained insight into the complex mechanisms that control bacterial pathogenesis and, as a result, have developed new theories about how independent mechanisms may have become intertwined during evolution. The research, published by Cell Press in the October 10th issue of the journal Molecular Cell, may lead to strategies for developing more effective therapeutics against the human pathogen responsible for most of the antibiotic-resistant infections contracted in the community.

Bacteria have evolved mechanisms called quorum-sensing systems that allow for rapid communication between cells. "In pathogenic bacteria, these systems were first described as virulence regulators, whereas it has been shown more recently that quorum-sensing control is also aimed to respond to changing environmental conditions via metabolic adaptations," explains lead study author Dr. Michael Otto from the Laboratory of Human Bacterial Pathogenesis at Rock Mountain Laboratories.

Dr. Otto and colleagues studied S. aureus, a major human pathogen that is the most common cause of bacterial infections in the community and the hospital. Many strains are resistant to a wide spectrum of antibiotics, including methicillin (methicillin-resistant S. aureus, MRSA). "Recent outbreaks of MRSA in the community form a novel major challenge for the public health system," says Dr. Otto. "It is thought that drugs which interfere with quorum-sensing regulators may prevent production of several virulence factors and be less likely to lead to resistance that drugs which directly kill bacteria."

The accessory gene regulator (agr) system is a pivotal regulator of virulence factor expression and a potential therapeutic target. The agr system initiates rapid target gene expression when bacterial cell density reaches a threshold level, exerting its effect through RNAIII. Phenol-soluble modulins (PSMs), which play an important role in the ability of S. aureus to evade the host immune system, are also controlled by agr but the molecular mechanisms of PSM regulation are not well understood.

The researchers examined the role of RNAIII within the agr regulatory system, with an emphasis on PSM regulation. They found that there are two distinct subsets of agr target gene regulation, an RNAIII-independent circuit that regulates metabolic genes and an RNAIII-dependent circuit controlling virulence. They went on to demonstrate that agr-dependent regulation of the PSM gene family is achieved by direct binding of a key agr response regulator protein.

The researchers concluded that control of virulence factors by RNAIII and quorum-sensing control of metabolism may have once been separate regulatory circuits. The circuits may have evolved a connection in order to allow for quick cell density-dependent change of virulence factor expression during infection as regulation by an RNA is thought to have a shorter response time than regulation by a protein.

"By discovering RNAIII-independent regulation of agr target genes, our findings establish a novel mechanism of target gene control by quorum-sensing in S. aureus and give insight into the evolution of quorum-sensing systems with regard to the connection of metabolism and virulence gene regulation," offers Dr. Otto.


Story Source:

The above story is based on materials provided by Cell Press. Note: Materials may be edited for content and length.


Cite This Page:

Cell Press. "Evolution Of Virulence Regulation In Staphylococcus Aureus." ScienceDaily. ScienceDaily, 18 October 2008. <www.sciencedaily.com/releases/2008/10/081009143657.htm>.
Cell Press. (2008, October 18). Evolution Of Virulence Regulation In Staphylococcus Aureus. ScienceDaily. Retrieved October 21, 2014 from www.sciencedaily.com/releases/2008/10/081009143657.htm
Cell Press. "Evolution Of Virulence Regulation In Staphylococcus Aureus." ScienceDaily. www.sciencedaily.com/releases/2008/10/081009143657.htm (accessed October 21, 2014).

Share This



More Health & Medicine News

Tuesday, October 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

How Nigeria Beat Its Ebola Outbreak

How Nigeria Beat Its Ebola Outbreak

Newsy (Oct. 20, 2014) The World Health Organization has declared Nigeria free of Ebola. Health experts credit a bit of luck and the government's initial response. Video provided by Newsy
Powered by NewsLook.com
Another Study Suggests Viagra Is Good For The Heart

Another Study Suggests Viagra Is Good For The Heart

Newsy (Oct. 20, 2014) An ingredient in erectile-dysfunction medications such as Viagra could improve heart function. Perhaps not surprising, given Viagra's history. Video provided by Newsy
Powered by NewsLook.com
Ebola Worries End for Dozens on U.S. Watch Lists

Ebola Worries End for Dozens on U.S. Watch Lists

Reuters - US Online Video (Oct. 20, 2014) Forty-three people who had contact with Thomas Eric Duncan, the first person diagnosed with Ebola in the U.S., were cleared overnight of twice-daily monitoring after 21 days of showing no symptoms. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
CDC Calls for New Ebola Safety Guidelines

CDC Calls for New Ebola Safety Guidelines

AP (Oct. 20, 2014) Centers for Disease Control and Prevention Director Dr. Tom Frieden laid out new guidelines for health care workers when dealing with the deadly Ebola virus including new precautions when taking off personal protective equipment. (Oct. 20) 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:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

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