Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Waiting for the right moment

26.08.2010
Bacterial pathogens delay their entry into cells

Pathogens make themselves feel at home in the human body, invading cells and living off the plentiful amenities on offer. However, researchers at the Max Planck Institute for Infection Biology, Berlin, together with colleagues at Harvard University, reveal an opposite strategy used to ensure infection success. Pathogens can actually delay their entry into cells to ensure their survival. Upon cell contact, bacteria trigger a local strengthening of the cellular skeleton with the aid of signalling molecules, allowing them to remain outside the cell. The researchers also show that this strategy, unknown until now, is used by certain intestinal pathogens as well. (PLoS Biology, 24th of August 2010)


Neisseria gonorrhoeae bacteria, forming micro-colonies on the surface of a human cell, stimulate signals to stabilize their extracellular life style. Image: Max Planck Institute for Infection Biology

Infection with the sexually transmitted bacterium Neisseria gonorrhoeae can lead to an inflammation of the urogenital tract, the uterus and ovaries. By means of thread-shaped proteins on its surface called pili, the bacterium attaches itself to the cell membrane. Once attached, the bacteria undergo rapid changes of their surface structure to avoid recognition by the host’s immune system. Only during the later stages of infection will the pathogens penetrate cells and occasionally advance into deeper tissues to find further breeding ground.

Until now scientists were firmly focused on understanding the tricks used by these pathogens to enter cells. The results of the Berlin-based researchers suggest, however, that bacteria may spend as much effort in resisting cell entry. Host cells tend to generate tiny vesicles by which they transport bacteria inadvertently into the interior. The researchers have now shed some light on the signals which prevent the bacteria from being ‘swallowed’. Upon fastening themselves to the cell surface, the bacteria induce a sequence of events that results in the strengthening of the cell skeleton directly beneath the point of attachment. The structural protein Actin is transported to attachment sites, where it forms a strong, supportive chain. In tandem, another structural protein Caveolin-1 and the signalling proteins VAV2 and RhoA are recruited to the cell membrane where they play a central role in effectively maintaining N. gonorrhoeae in the extracellular milieu.

Better outside than inside

These results have opened up new perspectives in understanding the course of infections: "For a long time it was thought that most pathogens strive to enter cells quickly. However, the opposite may be the case. It seems the bacteria prolong their extracellular existence in order to survive", declares Thomas F. Meyer of the Max Planck Institute of Infection Biology. By anchoring to the cell via pili proteins and assembling an underlying support skeleton, the pathogen is buffered against the often inhospitable conditions of the extracellular environment.

By extrapolating their findings to the intestinal bacteria Escherichia coli, the scientists have indicated that the strategy of delaying entry into cells to ensure survival may be widespread among pathogens, possibly even the bacterial agents of meningitis and pneumonia. These newly discovered signalling pathways may therefore have exciting implications for the prevention of infection.

Original work:

Jan Peter Boettcher, Marieluise Kirchner, Yuri Churin, Alexis Kaushansky, Malvika Pompaiah, Hans Thorn, Volker Brinkmann, Gavin MacBeath, Thomas F. Meyer
Tyrosine-phosphorylated caveolin-1 blocks bacterial uptake by inducing Vav2-RhoA-mediated cytoskeletal rearrangements

PLoS Biology, August 24, 2010

Contact:

Prof. Dr. Thomas F. Meyer
Max Planck Institute for Infection Biology, Berlin
Tel.: +49 30 28 460-400
E-mail: meyer@mpiib-berlin.mpg.de

Barbara Abrell | EurekAlert!
Further information:
http://www.mpg.de/english/

More articles from Life Sciences:

nachricht Multi-institutional collaboration uncovers how molecular machines assemble
02.12.2016 | Salk Institute

nachricht Fertilized egg cells trigger and monitor loss of sperm’s epigenetic memory
02.12.2016 | IMBA - Institut für Molekulare Biotechnologie der Österreichischen Akademie der Wissenschaften GmbH

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>