Navigation Links
Salmonella utilize multiple modes of infection
Date:4/21/2011

Scientists from the Helmholtz Centre for Infection Research (HZI) in Braunschweig, Germany have discovered a new, hitherto unknown mechanism of Salmonella invasion into gut cells: In this entry mode, the bacteria exploit the muscle power of cells to be pulled into the host cell cytoplasm. Thus, the strategies Salmonella use to infect cells are more complex than previously thought. According to the World Health Organization, the number of Salmonella infections is continuously rising, and the severity of infections is increasing. One of the reasons for this may be the sophisticated infection strategies the bacteria have evolved. The striking diversity of invasion strategies may allow Salmonella to infect multiple cell types and different hosts.

"Salmonella do not infect their hosts according to textbook model," says Theresia Stradal, group leader at the Helmholtz Centre in Braunschweig, who has recently accepted a call to the University of Mnster. "Only a single infection mechanism has seriously been discussed in the field up till now without understanding all the details," adds Klemens Rottner, now Professor at the University of Bonn.

All entry mechanisms employed by Salmonella target the so-called actin cytoskeleton of the host cell. Actin can polymerise into fine and dynamic fibrils, also called filaments, which associate into networks or fibres. These structures stabilise the cell and enable it to move, as they are constantly built up and taken down. One of the most important core elements is the Arp2/3 complex that nucleates the assembly of actin monomers into filaments.

Extensions of the cell membrane are filled with actin filaments. In the commonly accepted infection mechanism, Salmonella abuses the Arp2/3 complex to enter the host cell: the bacteria activate the complex and thus initiate the formation actin filaments and development of prominent membrane extensions, so-called ruffles. These ruffles surround and enclose the bacteria so that they end up in the cell interior. Last year, the research groups headed by Theresia Stradal and Klemens Rottner discovered that Salmonella can also reach the cell interior without initiating membrane ruffles. With this, the researchers disproved a long-standing dogma.

In their recent study, the experts from Braunschweig now describe a completely unknown infection mechanism. The results have just appeared in the latest issue of the leading journal Cell Host & Microbe. In this new infection mechanism, Salmonella also manipulate the actin cytoskeleton of the host cell. This time, however, they do not induce the generation of new filaments, but activate the motor protein myosin II. The interplay of actin and myosin II in muscle cells is well known: in a contracting muscle, myosin and actin filaments slide along each other and this way shorten the muscle; it contracts.

In epithelial cells, the contractile structures are less organised but work similarly. Here, actin and myosin II form so-called stress fibres that tightly connect to the membrane. During an infection, stress fibres at the entry site can contract and pull the bacteria into the cell. "This way of infection operates independently from the Arp2/3 complex, the central component of the 'classic' infection mechanism," says Jan Hnisch, who worked on this project as postdoctoral researcher.


'/>"/>

Contact: Dr. Bastian Dornbach
bastian.dornbach@helmholtz-hzi.de
49-531-618-11407
Helmholtz Association of German Research Centres
Source:Eurekalert

Related biology news :

1. The medium is the message: Manipulating salmonella in spaceflight curtails infectiousness
2. Yale researchers uncover secrets of salmonellas stealth attack
3. Hygienic Lab at U. Iowa first to confirm salmonella in nationwide outbreak
4. Probiotic without effect against Salmonella
5. Faster Salmonella detection now possible with new technique
6. Mechanism uncovered behind Salmonella virulence and drug susceptibility
7. MU scientist develops salmonella test that makes food safer, reduce recalls
8. Zooming in on the weapons of Salmonella
9. Genetic testing for breast or ovarian cancer risk may be greatly underutilized
10. Response to immune protein determines pathology of multiple sclerosis
11. Multiple sclerosis research charges ahead with new mouse model of disease
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:3/22/2017)... 21, 2017   Neurotechnology , a provider ... today announced the release of the SentiVeillance ... improved facial recognition using up to 10 surveillance, ... computer. The new version uses deep neural-network-based facial ... it utilizes a Graphing Processing Unit (GPU) for ...
(Date:3/22/2017)... YORK , March 21, 2017 ... Marketing Cloud used by retailers such as 1-800-Flowers ... its platform — Product Recommendations and Replenishment. Using Optimove,s ... give more personalized product and replenishment recommendations to ... but also on predictions of customer intent drawn ...
(Date:3/22/2017)... , March 21, 2017 Vigilant Solutions ... serving law enforcement agencies, announced today the appointment of ... director of public safety business development. Mr. ... enforcement experience, including a focus on the aviation transportation ... most recent position, Mr. Sheridan served as the Aviation ...
Breaking Biology News(10 mins):
(Date:3/22/2017)... ... 21, 2017 , ... Proper glycosylation is critical for the ... and/or decrease in antibody-dependent cellular cytotoxicity or complement-dependent cytotoxicity, there is a growing ... , To meet this demand, the team at SCIEX has developed a Fast ...
(Date:3/22/2017)... ... March 21, 2017 , ... ... unveiled its innovative Quantum peristaltic pump with patented ReNu single-use (SU) cartridge ... new standard for high-pressure feed pumps in SU tangential flow filtration (TFF), ...
(Date:3/22/2017)... N.J. and PETACH TIKVAH, Israel ... Inc. (NASDAQ: BCLI), a leading developer of adult stem ... Chaim Lebovits , Chief Executive Officer, will provide an ... Sachs Associates 2 nd Annual Neuroscience Biopartnering and ... at the New York Academy of Sciences. ...
(Date:3/20/2017)... ... ... and Whitehouse Laboratories, divisions of Albany Molecular Research, Inc, are looking forward to ... (PDA), the New York Interphex Show will open on March 21 and run through ... the educational and networking opportunities are extremely valuable. INTERPHEX is viewed as the key ...
Breaking Biology Technology: