Featured Research

from universities, journals, and other organizations

The killer within: A novel bacterial suicide mechanism

Date:
March 23, 2011
Source:
Public Library of Science
Summary:
The zeta toxins are a family of proteins that are normally present within various pathogenic bacteria and can mysteriously trigger suicide when the cells undergo stress. Researchers in Germany have now found the mechanism underlying this programmed bacterial cell death.

The zeta toxins are a family of proteins that are normally present within various pathogenic bacteria and can mysteriously trigger suicide when the cells undergo stress. A team led by Anton Meinhart at the Max Planck Institute for Medical Research in Heidelberg has now found the mechanism underlying this programmed bacterial cell death.

Their paper, publishing in the online, open access journal PLoS Biology, reports that zeta toxins convert a compound required for bacterial cell wall synthesis into a poison that kills bacteria from within. In the future it may be possible to hijack this mechanism for bacterial defense and to design drugs that mimic these toxins

Most bacteria harbor toxin-antitoxin (TA) systems, in which a bacterial toxin lies dormant under normal conditions, prevented from being active by its antitoxin counterpart. As long as the antitoxin is present, the bacterium can continue to exist and is not affected by the TA system. Under conditions of stress, however, the antitoxin is degraded, freeing the toxin to attack its host from within. Although the family of zeta toxins was discovered almost 20 years ago, their deadly mechanism has been enigmatic until now.

The first author on the paper, Hannes Mutschler, and his colleagues studied the molecular mechanism of action of the zeta toxin PezT from the PezAT (Pneumococcal epsilon zeta Antitoxin Toxin) system using the model bacterium Escherichia coli. The PezAT system is found in the major human pathogen Streptococcus pneumoniae -- a bacterium that causes serious infections such as pneumonia, septicaemia and meningitis. Bacterial cells in which PezT was activated showed symptoms of poisoning similar to the effects of penicillin. This involved first stalling in the middle of their division stage, and later the intersection zone between the two cell bodies burst and the cells died. The team showed that PezT and other zeta toxins are novel enzymes that transform the essential sugar building block UNAG (UDP-N-acetylglucosamine) into a toxic molecule. This molecule (UNAG-3P) inhibits the growth of the bacterial cell wall, causing the cells to burst and die.

The findings also enabled the scientists to explain a hitherto paradoxical phenomenon; namely, that the supposedly lethal activity of pneumococcal zeta toxin PezT can eventually boost the pneumococcal infection rate of the entire attacking cellular population. The activation of PezT actively causes individual bacteria to burst and release their cell contents. However, other individuals, which are metabolically less active, can survive the toxin's activity to some extent. In this process, the accelerated release of bacterial venoms by a subpopulation supports the surviving cells in their attack on the immune system during infection. It therefore seems that individual pneumococci altruistically sacrifice themselves during infection for the good of the overall population.

"UNAG-3P is a valuable lead-compound for the development of new broad-band antibiotics," says Meinhart, "since it will kill most rapidly growing bacteria." Thus, knowlege of the mechanism of zeta toxins could bring research on antibiotics a major step forward in the battle against bacterial resistance.


Story Source:

The above story is based on materials provided by Public Library of Science. Note: Materials may be edited for content and length.


Journal Reference:

  1. Hannes Mutschler, Maike Gebhardt, Robert L. Shoeman, Anton Meinhart. A Novel Mechanism of Programmed Cell Death in Bacteria by Toxin–Antitoxin Systems Corrupts Peptidoglycan Synthesis. PLoS Biology, 2011; 9 (3): e1001033 DOI: 10.1371/journal.pbio.1001033

Cite This Page:

Public Library of Science. "The killer within: A novel bacterial suicide mechanism." ScienceDaily. ScienceDaily, 23 March 2011. <www.sciencedaily.com/releases/2011/03/110322172215.htm>.
Public Library of Science. (2011, March 23). The killer within: A novel bacterial suicide mechanism. ScienceDaily. Retrieved August 21, 2014 from www.sciencedaily.com/releases/2011/03/110322172215.htm
Public Library of Science. "The killer within: A novel bacterial suicide mechanism." ScienceDaily. www.sciencedaily.com/releases/2011/03/110322172215.htm (accessed August 21, 2014).

Share This




More Plants & Animals News

Thursday, August 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Possible Ebola Patient in Isolation at California Hospital

Possible Ebola Patient in Isolation at California Hospital

Reuters - US Online Video (Aug. 20, 2014) — A patient who may have been exposed to the Ebola virus is in isolation at the Kaiser Permanente South Sacramento Medical Center. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Flower Power! Dandelions Make Car Tires?

Flower Power! Dandelions Make Car Tires?

Reuters - Business Video Online (Aug. 20, 2014) — Forget rolling on rubber, could car drivers soon be traveling on tires made from dandelions? Teams of scientists are racing to breed a type of the yellow flower whose taproot has a milky fluid with tire-grade rubber particles in it. As Joanna Partridge reports, global tire makers are investing millions in research into a new tire source. Video provided by Reuters
Powered by NewsLook.com
Unsustainable Elephant Poaching Killed 100K In 3 Years

Unsustainable Elephant Poaching Killed 100K In 3 Years

Newsy (Aug. 20, 2014) — Poachers have killed 100,000 elephants between 2010 and 2012, as the booming ivory trade takes its toll on the animals in Africa. Video provided by Newsy
Powered by NewsLook.com
Awesome New Camouflage Sheet Was Inspired By Octopus Skin

Awesome New Camouflage Sheet Was Inspired By Octopus Skin

Newsy (Aug. 19, 2014) — Scientists have developed a new device that mimics the way octopuses blend in with their surroundings to hide from dangerous predators. 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.

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