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:11/29/2016)... VILNIUS, Lithuania , Nov. 29, 2016 ... high-precision biometric identification and object recognition technologies, ... kit (SDK) for fingerprint recognition solutions that ... extract a fingerprint template using less than ... used in compact devices that have limited ...
(Date:11/22/2016)... According to the new market research report "Biometric System Market by ... Component (Hardware and Software), Function (Contact and Non-contact), Application, and Region - ... grow from USD 10.74 Billion in 2015 to reach USD 32.73 Billion ... Continue Reading ... ...
(Date:11/17/2016)... LONDON , Nov. 17, 2016 Global Market ... and Public Biobanks (Disease-Based Banks, Population-Based Banks and Academics) market ... Geographical analysis for Private Biobanks shows the highest Compounded Annual ... Asia-Pacific region during the analysis period 2014-2020. ... a CAGR of 9.95% followed by Europe ...
Breaking Biology News(10 mins):
(Date:12/7/2016)... 7, 2016  Muse bio, a privately-held company leading ... that Dr. Kevin Ness has been appointed ... Directors. Kevin succeeds Muse bio,s founding ... Chief Science Officer as well as remains Slade Professor, ... BioDesign Center at the RAS Energy Institute at the ...
(Date:12/7/2016)... ... December 07, 2016 , ... ... and online shopping cart. The new website has been designed to provide the ... components allow customers to access detailed product information, read educational industry content as ...
(Date:12/6/2016)... (PRWEB) , ... December 06, ... ... of the Almac Group, the world’s largest privately-held contract pharmaceutical development and ... inVentiv Health, a leading biopharma outsourcing company combining a leading CRO and ...
(Date:12/6/2016)... ... December 06, 2016 , ... ... ("GPP") portfolio company, today announced it has acquired the assets of Theorem ... Chiltern International and focuses on clinical trial drug packaging, labeling, storage, reconciliation, ...
Breaking Biology Technology: