Navigation Links
Infection biology: How Legionella subverts to survive
Date:7/18/2013

Bacteria of the genus Legionella have evolved a sophisticated system to replicate in the phagocytic cells of their hosts. Researchers at Ludwig-Maximilians-Universitaet (LMU) in Munich have now identified a novel component of this system.

In humans, Legionella is responsible for the so-called Legionnaires' disease, a form of bacterial pneumonia that is often lethal. The bacteria can also cause Pontiac fever, a flu-like condition characterized by coughing and vomiting. Most Legionella-associated illnesses in humans are caused by Legionella pneumophila.

These microorganisms are found in soil, lakes and rivers, and can enter our water supply via the groundwater. The greatest risk of human infection arises when the bacteria colonize air-conditioning ducts or piping used to transport warm water. Persons can be infected when they inhale contaminated aerosols in the shower, for instance.

The research group led by Hubert Hilbi, Professor of Medical Microbiology at LMU, studies how these intracellular parasites survive and replicate in phagocytic cells of their eukaryotic hosts or in the environment. For instance, the pathogen can grow and proliferate in the amoeba Dictyostelium, which normally preys on soil bacteria, engulfing and digesting them. But Legionella turns the tables, resists degradation and continues to grow in the amoeba until it is so full of bacteria that it bursts.

Legionella sabotages the immune system

When L. pneumophila cells infect the human lung, essentially the same thing happens. The bacteria are taken up by white blood cells called macrophages, which normally clear bacterial pathogens from the circulation. But instead of being consumed, the bacteria replicate in the macrophages and ultimately destroy them. Robbed of its first line of defense, the immune system has difficulty coping with the infection, and a life-threatening pneumonia may develop.

The biochemical processes that enable the parasites to outwit their temporary hosts are highly complex. Thus, L. pneumophila secretes around 300 proteins into the infected cell, which is forced to redirect its resources for the bacterium's benefit.

Hilbi and his colleagues have now characterized one of these proteins and describe its mode of action for the first time. This factor, called RidL, disrupts an intracellular transport system that is necessary for the elimination of ingested bacteria. RidL binds to the so-called retromer complex, which is needed for the continued recycling of receptors, which deliver degradative enzymes to phagosomes containing bacteria destined for digestion. "We demonstrate that Legionella blocks the retromer-dependent transport route, thus promoting its own survival in the cell," Hilbi explains. This function is unique. "Proteins that act in this way are otherwise unknown in the bacterial world, and are not found in higher organisms either," he adds.


'/>"/>

Contact: Luise Dirscherl
dirscherl@lmu.de
49-892-180-2706
Ludwig-Maximilians-Universitt Mnchen
Source:Eurekalert

Related biology news :

1. Queens scientists seek vaccine for Pseudomonas infection
2. BPA could affect reproductive capabilities, cause infection of the uterus
3. To drive infections, a hijacking virus mimics a cells signaling system
4. Women & Infants participating in study of treatment of common viral infection in pregnancy
5. Bartonella infection associated with rheumatoid illnesses in humans
6. Salmonella infection, but not as we know it
7. Vitamin D supplements may protect against viral infections during the winter
8. New data suggests HIV superinfection rate comparable to initial HIV infection
9. How alert hospital employees improved hospitals MSRA infection rate
10. Childhood virus infection linked to prolonged seizures with fever
11. Infection biology: The elusive third factor
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/27/2016)... -- Research and Markets has announced the addition of ... their offering. The report forecasts ... grow at a CAGR of 12.28% during the period 2016-2020. ... market analysis with inputs from industry experts. The report covers the ... report also includes a discussion of the key vendors operating in ...
(Date:6/22/2016)... June 22, 2016   Acuant , ... verification solutions, has partnered with RightCrowd ® ... for Visitor Management, Self-Service Kiosks and Continuous ... that add functional enhancements to existing physical ... and venues with an automated ID verification ...
(Date:6/21/2016)... 2016 NuData Security announced today that Randy ... principal product architect and that Jon Cunningham ... development. Both will report directly to Christopher ... reflect NuData,s strategic growth in its product and ... demand and customer focus values. ...
Breaking Biology News(10 mins):
(Date:12/7/2016)... ... 07, 2016 , ... A new study published in the ... treated, advanced pancreatic cancer, liquid biopsies are not yet an adequate substitute for ... blood sampling may improve the value of a blood-based test.” The study was ...
(Date:12/7/2016)... Corp. ("Zenith" or the "Company") announces webcast details for a ... and Special Meeting. The Zenith Annual and ... 15, 2016 at Mount Royal University, ... Gate SW, Calgary, Alberta , commencing at ... circular, containing the matters to be considered at the meeting, ...
(Date:12/7/2016)... , Dec. 7, 2016  Vyriad Inc. announced ... to the company,s Board of Directors. "We ... we build our business and develop our oncolytic viruses ... therapy," said Stephen Russell , MD, PhD, CEO ... , share our vision and passion for making a ...
(Date:12/7/2016)... 7, 2016 Regen BioPharma Inc. (OTCQB: ... of Molecular Sciences a team of scientists in ... have demonstrated that expression of NR2F6 in patients with early ... NR2F6 in patient,s cervical cancer tissue as well as in ... "This is an interesting study and the first that I ...
Breaking Biology Technology: