Navigation Links
Neisseria meningitidis disseminates itself by sending out 'scouts'

Although, in the majority of cases, the localized presence of Neisseria meningitidis in the throat has no consequence, it can sometimes lead to meningitis or septicaemia. The seriousness of these two infections is driving researchers from around the world to improve their understanding of the mode of operation of this bacterium, which, once it leaves its favourite location (the throat) becomes extremely dangerous. The Avenir team directed by Guillaume Dumnil within Inserm Mixed Research Unit 970, "Paris centre de recherche cardiovasculaire" at the Universit Paris Descartes, has recently discovered how this bacterium disseminates, leaving the throat to pass into the bloodstream. The results of this research have been published in the 11 February 2011 issue of the journal, Science. Neisseria meningitidis is a bacterium specific to man. It is frequently present in the non-pathogenic state in the throat of healthy carriers (5% to 30% of the population).

Its persistence in the organism can however prove dangerous in some cases. The location where the bacteria multiply, the throat, represents a port of entry, from where it disseminates into the bloodstream and may penetrate into the brain. In both these cases, the infection becomes very serious since it results in septicaemia or meningitis. Unless dealt with quickly, the mortality rate linked to these two infections is very high.

Guillaume Dumnil and his Inserm research team were, therefore, interested to understand more about this bacterium which, when it passes into the bloodstream, becomes very dangerous. "Certain advances made in the past few years provided the starting point for this work, which is published in Science", he explained. We know, for example, that Neisseria meningitidis are equipped with special structures known as pili. These allow the bacteria to adhere to the cells of the throat and to multiply and form aggregates there. We are closely studying the main protein which makes up the pili; namely, pilin", adds Guillaume Dumnil.

The researchers then discovered that the protein underwent various modifications over time. One of these, in particular, has proved more interesting than the others: The addition of a phosphoglycerol. This chemical group once grafted onto the pilin, gives the signal for dissemination.

Bacteria isolated from the colony depart as "scouts"

Following these initial results, the researchers discovered the presence of a gene which enabled the transfer of phosphoglycerol onto the pilin: the gene, pptB. This gene only becomes fully functional when the bacteria is in contact with the cells lining the wall of the throat. The frantic activity of the pptB gene causes the addition of phosphoglycerol to the pilin. This then loses one of its essential properties: its capacity to form aggregates. As a consequence, some of the bacteria detach themselves from the colony and, little by little, are disseminated. This strategy is used by the bacteria in order to colonize other areas of the throat and to cross the cells lining it. "This phenomena could almost be compared with the formation of metastases in cancer", says Guillaume Dumnil.

This is the first time that scientists have been able to accurately identify the chain of events which controls the bacteria in the bloodstream. It is a first step. "We now know how the Neisseria meningitidis passes from the throat into the blood. We hope to be able to demonstrate that an identical process is involved when the bacteria passes from the blood into the brain, instigating meningitis", concludes Guillaume Dumnil.

Furthermore, if the researchers were able to find molecules which can block this dissemination, they would have both a preventative tool (blocking colonization from the throat and passage into the bloodstream) and a therapeutic tool (limiting colonization from the blood vessels and transmission into the brain).

Although the strategy developed by Neisseria meningitidis ensures its multiplication in the throat, and therefore its survival over the course of evolution, it is also responsible for the death of the host organism and hence its own death. Further proof that living in harmony with a host is not easy.


Contact: Sverine Ciancia
INSERM (Institut national de la sant et de la recherche mdicale)

Related biology news :

1. Scripps scientists develop first examples of RNA that replicates itself indefinitely
2. Scientists discover how deadly fungus protects itself
3. Biodiversity itself begets a species cascade, researchers say
4. No longer a gray area: Our hair bleaches itself as we grow older
5. A window that washes itself?
6. Your body recycling itself -- captured on film
7. Wildflower armors itself against disease
8. Africa can feed itself in a generation: Study
Post Your Comments:
(Date:3/29/2016)... 2016 LegacyXChange, Inc. (OTC: ... SelectaDNA/CSI Protect are pleased to announce our successful effort ... variety of writing instruments, ensuring athletes signatures against counterfeiting ... from athletes on LegacyXChange will be assured of ongoing ... Bill Bollander , CEO states, "By ...
(Date:3/22/2016)... India , March 22, 2016 /PRNewswire/ ... market research report "Electronic Sensors Market for Consumer ... Proximity, & Others), Application (Communication & IT, ... Geography - Global Forecast to 2022", published ... industry is expected to reach USD 26.76 ...
(Date:3/21/2016)... WAKEFIELD, Massachusetts , March 22, 2016 ... and facial recognition with passcodes for superior security ... MESG ), a leading provider of secure digital communications ... pilot their biometric technology and offer enterprise customers, particularly ... provide secure facial recognition and voice authentication within a ...
Breaking Biology News(10 mins):
(Date:6/23/2016)... , June 23, 2016  Blueprint Bio, a ... discoveries to the medical community, has closed its Series ... Matthew Nunez . "We have received a ... the capital we need to meet our current goals," ... provide us the runway to complete validation on the ...
(Date:6/23/2016)... ... June 23, 2016 , ... ClinCapture, the ... Convention Center and will showcase its product’s latest features from June 26 to ... a scientific poster on Disrupting Clinical Trials in The Cloud during the conference. ...
(Date:6/23/2016)... -- Amgen (NASDAQ: AMGN ) today announced a ... sciences incubator to accelerate the development of new therapies ... QB3@953 was created to help high-potential life science and ... stage organizations - access to laboratory infrastructure. ... "Amgen Golden Ticket" awards, providing each winner with one ...
(Date:6/22/2016)... June 22, 2016 Research and Markets has ... report to their offering. ... 2014 from $29.3 billion in 2013. The market is expected to ... from 2015 to 2020, increasing from $50.6 billion in 2015 to ... forecasts during the forecast period (2015 to 2020) are discussed. As ...
Breaking Biology Technology: