Navigation Links
When intestinal bacteria go surfing
Date:3/19/2009

The bacterium Escherichia coli is part of the healthy human intestinal flora. However, E. coli also has pathogenic relatives that trigger diarrhea illnesses: enterohemorrhagic E.coli bacteria. During the course of an infection they infest the intestinal mucosa, causing injury in the process, in contrast to benign bacteria.

The EHECs adhere to the surface of the mucosal cells and alter them internally: a part of the cellular supportive skeleton - the actin skeleton - is rearranged in such a manner that the cell surface beneath the bacteria forms plinth-like growths, so-called pedestals. The bacteria are securely anchored to this pedestal; the pedestals, in contrast, are mobile. This enables the bacteria, seated upon them, to surf over the cell surface and reproduce upon it, without being flushed from the intestine. But how do the bacteria bring the host cells to convert the actin skeleton? Researchers at the Helmholtz Centre for Infection Research (HZI) have now identified the signal pathway that leads to the formation of this pedestal.

"Prerequisite for this signal pathway is a special secretion system - a sort of molecular syringe, through which the bacteria insert entire proteins in the host cell," explains Theresia Stradal, head of the Signal Transduction and Motility research group at HZI. Two factors, Tir and EspFU, are brought into the host cell from the bacterium for pedestal formation. Following this, the host cell presents Tir on its surface; the bacterium recognises "its" molecule Tir and adheres to the host cell. EspFU then triggers the signal for local actin conversion.

"It has been unclear thus far how the two bacterial effectors Tir and EspFU enter into contact with one another in the host cell," says Theresia Stradal. Her research group has now found the missing link: "The molecule comes from the host cell, is called IRSp53 and gathers on the cell surface, directly beneath the bacteria sitting on it," explains cell biologist Markus Ladwein, who is also involved in the project. IRSp53, then, establishes the connection between Tir and EspFU. It ensures that actin conversion is concentrated locally. Together with the biochemist Dr. Stefanie Wei, a former post-graduate student with the research group, Markus Ladwein also provided the counter evidence: "Cells in which IRSp53 is lacking are no longer able to form pedestals for the bacteria."

The signal pathway clarified by the Braunschweig researchers published today in the journal Cell Host & Microbe is a good example of how pathogenic bacteria develop progressively with their host. With the aid of bacterial factors, they therefore manage to simulate signals and set in motion complex processes in the host, which they then abuse for their own purposes.


'/>"/>

Contact: Dr. Bastian Dornbach
bad@helmholtz-hzi.de
49-053-161-811-407
Helmholtz Association of German Research Centres
Source:Eurekalert

Related biology news :

1. Soy isoflavone may inhibit common gastrointestinal illness in infants
2. Study uncovers clues to cystic fibrosis gene dysfunction and gastrointestinal disease
3. Study finds healthy intestinal bacteria within chicken eggs
4. USC researchers identify gene variant associated with both autism and gastrointestinal dysfunction
5. Shuttle brings space-grown strep bacteria back for study
6. The worlds oldest bacteria
7. Bacteria from sponges make new pharmaceuticals
8. Boston University biomedical engineers find chink in bacterias armor
9. University of Leicester scientists discover technique to help friendly bacteria
10. Spaceflight shown to alter ability of bacteria to cause disease
11. A tiny pinch from a z-ring helps bacteria cells divide
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/20/2016)... DALLAS , June 20, 2016 ... criminal justice technology solutions for public safety, investigation, ... by the prisons involved, it has secured the ... Corrections (DOC) facilities for Managed Access Systems (MAS) ... (4) additional facilities to be installed by October, ...
(Date:6/15/2016)... New York , June 15, 2016 /PRNewswire/ ... a new market report titled "Gesture Recognition Market by ... and Forecast, 2016 - 2024". According to the report, ... USD 11.60 billion in 2015 and is estimated ... reach USD 48.56 billion by 2024.  ...
(Date:6/9/2016)... TURKU, Finland , June 9, 2016 ... French National Police deploy Teleste,s video security solution to ensure ... France during the major tournament ... and data communications systems and services, announced today that its ... Police Prefecture to back up public safety across ...
Breaking Biology News(10 mins):
(Date:6/24/2016)... , June 24, 2016 Epic ... sensitively detects cancers susceptible to PARP inhibitors by ... tumor cells (CTCs). The new test has already ... therapeutics in multiple cancer types. Over ... DNA damage response pathways, including PARP, ATM, ATR, ...
(Date:6/23/2016)... ... June 23, 2016 , ... UAS LifeSciences, one of ... their brand, UP4™ Probiotics, into Target stores nationwide. The company, which has been ... Target to its list of well-respected retailers. This list includes such fine stores ...
(Date:6/23/2016)... -- Houston Methodist Willowbrook Hospital has signed a ... serve as their official health care provider. As ... provide sponsorship support, athletic training services, and most ... athletes and families. "We are excited ... to bring Houston Methodist quality services and programs ...
(Date:6/23/2016)... SAN FRANCISCO , June 23, 2016   ... it has secured $1 million in debt financing from ... to ramp up automation and to advance its drug ... for its new facility. "SVB has been ... goes beyond the services a traditional bank would provide," ...
Breaking Biology Technology: