Navigation Links
Neisseria meningitidis disseminates itself by sending out 'scouts'
Date:2/17/2011

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
severine.ciancia@inserm.fr
33-144-236-086
INSERM (Institut national de la sant et de la recherche mdicale)
Source:Eurekalert

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:
*Name:
*Comment:
*Email:
(Date:3/24/2017)... Research and Markets has announced the addition of the ... Forecast to 2025" report to their offering. ... The Global Biometric Vehicle Access System ... over the next decade to reach approximately $1,580 million by 2025. ... forecasts for all the given segments on global as well as ...
(Date:3/23/2017)... 2017 Research and Markets has announced the ... Trends - Industry Forecast to 2025" report to their offering. ... The Global ... of around 8.8% over the next decade to reach approximately $14.21 ... market estimates and forecasts for all the given segments on global ...
(Date:3/22/2017)... Optimove , provider of the ... as 1-800-Flowers and AdoreMe, today announced two new ... Using Optimove,s machine learning algorithms, these features allow ... recommendations to their customers based not just on ... intent drawn from a complex web of data ...
Breaking Biology News(10 mins):
(Date:7/25/2017)... ... July 25, 2017 , ... ... microbiome and improve efficiency of livestock farming while reducing the use of antibiotics ... additional intellectual property from Cornell University. , These new proprietary technologies expand ...
(Date:7/24/2017)... Intralytix, Inc. announced that it received $17.5 million in ... This investment marks the beginning of a close collaboration ... for various benefits in human health and in other ... As a global key player in yeasts ... for baking, food taste & pleasure, health care, and ...
(Date:7/24/2017)... ... July 24, 2017 , ... ... today announced that the stock market news outlet had initiated coverage on ... testing that screens and identifies exposure, progression and risk analysis from specific ...
(Date:7/20/2017)... ... 20, 2017 , ... Resoundant, Inc. is pleased to introduce ... the U.S. that offer MR Elastography for liver fibrosis staging. MR Elastography ... staging liver fibrosis assessment. , “MRE:connect was created in response to an increasing ...
Breaking Biology Technology: