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 For a chimpanzee, one good turn deserves another
27.06.2017 | Max-Planck-Institut für Mathematik in den Naturwissenschaften (MPIMIS)

nachricht New method to rapidly map the 'social networks' of proteins
27.06.2017 | Salk Institute

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Touch Displays WAY-AX and WAY-DX by WayCon

27.06.2017 | Power and Electrical Engineering

Drones that drive

27.06.2017 | Information Technology

Ultra-compact phase modulators based on graphene plasmons

27.06.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>