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 A Map of the Cell’s Power Station
18.08.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

nachricht On the way to developing a new active ingredient against chronic infections
18.08.2017 | Deutsches Zentrum für Infektionsforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

A Map of the Cell’s Power Station

18.08.2017 | Life Sciences

Engineering team images tiny quasicrystals as they form

18.08.2017 | Physics and Astronomy

Researchers printed graphene-like materials with inkjet

18.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>