Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

‘Big Brother’ surveillance stops Salmonella getting stressed out

11.12.2006
Scientists from Germany and the UK have discovered how pathogens such as Salmonella respond quickly to stress in its bacterial membrane or “skin”, giving insight into how the bacterium is able to adapt so rapidly to a multitude of harsh environments.

Salmonella food poisoning costs the UK economy around £1 billion every year and severe cases can become life threatening for the young and the elderly. The researchers from the Max Planck Institute for Infection Biology and the Institute of Food Research hope that a better understanding of how the pathogen copes with stress will help develop new ways of fighting and preventing infections.

When the bacterium infects its host, it must survive a range of harsh conditions from strong acids in the stomach, to anaerobic and salty environments in the intestine. To adapt to these different conditions, Salmonella must continuously remodel its bacterial “skin” by inserting outer membrane proteins (OMPs) into the cell wall which regulate the transport of salts and allow the bacterium to communicate with its environment. This research, published in the journal Molecular Microbiology, reveals that Salmonella uses a surveillance loop to constantly monitor levels of OMPs to respond fast to signs of stress by switching off protein expression using molecules called small RNAs (sRNAs). These bind to the messenger RNA (mRNA) molecules responsible for the production of OMPs.

“The OMP messenger RNA is unusually stable – it has a half-life of around 15 minutes compared with 5 minutes for other Salmonella mRNAs so it was a mystery how the bacterium could switch off OMP production so quickly” explains Professor Jay Hinton of the Institute of Food Research, “We discovered that a different type of RNA called sRNA binds to the OMP mRNA and blocks its action. The cell then degrades the resulting double stranded RNA molecule. Our novel finding is that these sRNAs called RybB and MicA are able to bind to so many different types of OMP mRNA molecule – most sRNAs bind to only one type.”

The research, supported by the Biotechnology and Biological Sciences Research Council (BBSRC), used a revolutionary new approach combining bioinformatics techniques with cutting edge microarray technology to first identify the sRNAs and then search the 5000 genes in the Salmonella genome for the targets to which they bind. The researchers then confirmed these results by studying a mutant strain lacking the sRNA mechanism.

“We call this a surveillance loop because it allows Salmonella to be constantly vigilant, just like George Orwell’s Big Brother” says Dr Joerg Vogel who led the research at the Max Planck Institute for Infection Biology. “As soon as a problem is detected, the bacterium responds in the same way as the police upon witnessing a crime on CCTV; in this case these small RNAs are deployed, rather than policemen. If Salmonella cannot detect and deal with the problem, however, it becomes extremely stressed.”

Researchers are hoping to apply the same technologies to other pathogenic bacteria. This knowledge could be used in the future to exploit the weaknesses of these dangerous bacteria and to help develop new antibacterials to combat infections when current antibiotics stop working. The proportion of Salmonella bacteria that are resistant to current antibiotics is increasing each year.

This research is particularly relevant as Christmas approaches; whilst only 1 in 20 of turkeys sold for meat in the UK are contaminated with Salmonella, two-thirds of these bacteria are resistant to one or more antibiotics, although researchers stress there is no danger to health if the meat is properly cooked. It is likely that the new surveillance loop discovered here is one of the tools that allow Salmonella to be so successful at infecting both animals and humans.

Salmonella Facts:

• Since the beginning of the 1990s, strains of Salmonella enterica sv. Typhimurium resistant to a range of antibiotics have emerged and are threatening to become a serious public health problem, particularly in developing countries.

• Since 1885, a total of 2213 types of salmonella have been identified. They vary in the severity of illness they cause.

• Symptoms of salmonellosis (food poisoning caused by Salmonella) are fever, headache, abdominal pain, diarrhoea, nausea and vomiting, and are usually self-limiting after a week. In some cases, particularly in the young and very elderly, dehydration can become severe and life threatening.

• Salmonella Typhimurium can be found in a broad range of animals, birds and reptiles as well as the environment. It causes food poisoning in humans mainly through the consumption of raw or undercooked contaminated food of animal origin - especially poultry, eggs, meat, salad vegetables and milk.

Zoe Dunford | alfa
Further information:
http://www.bbsrc.ac.uk

Further reports about: Max Planck Institute OMP RNA Salmonelle mRNA sRNA surveillance

More articles from Life Sciences:

nachricht The birth of a new protein
20.10.2017 | University of Arizona

nachricht Building New Moss Factories
20.10.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Terahertz spectroscopy goes nano

20.10.2017 | Information Technology

Strange but true: Turning a material upside down can sometimes make it softer

20.10.2017 | Materials Sciences

NRL clarifies valley polarization for electronic and optoelectronic technologies

20.10.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>