Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Flesh-eaters make skin creep

06.12.2001


Bacteria (red) persuade skin cells (green)to let them in.
© Nature


Bacteria give skin cells their marching orders.

Bacteria that cause potentially lethal ’flesh-eating’ infections make their entrance by telling skin cells to step aside. The bugs hijack the body’s signal for skin cells to become mobile.

Group A streptococci (GAS) normally infect the surface lining of the throat. But occasionally they penetrate skin or the tissues lining the airways, invading deep into the body and causing life-threatening disease.



Finding out how streptococci enter tissues doesn’t reveal why merely troublesome bacteria sometimes turn lethal. But it may lead to treatments for severe infections, called necrotizing fasciitis, and sore throats.

Michael Wessels and Colette Cywes at Harvard Medical School in Boston find that GAS are covered with a cloak of molecules that mimic a signal that is normally sent to mobilize cells1. "Cells don’t know any better - they think this is a signal to get up and move," says Wessels.

Like mortar being removed from a brick wall, the impenetrable layer of skin cells dissolves, allowing the bacteria in.

"This generates a new dogma," says Lukas Huber, a cell biologist at the Molecular Pathology Research Institute in Vienna, Austria. Invading bacteria normally infect and destroy individual cells. "Clearly [GAS] are much smarter than that," he says.

GAS’ deceitful cloak resembles a signalling chemical called hyaluronic acid. This is released when cells must be rearranged - to heal wounded skin, for example. "The bacteria subvert this normal function," says Wessels.

Hyaluronic acid - or its bacterial doppelganger - binds to a receptor on the cell surface called CD44. When this happens " the junctions [between the cells] just open," says Huber.

Wolf in sheep’s clothing

Wessels and Cywes infected laboratory cultures of human skin with GAS. They saw the skin-cell membranes ’ruffling’, a sign that they had let go of their neighbours. A mutant form of GAS unable to produce the deceptive molecular coat was unable to penetrate skin.

Wessels and Cywes are now working to prevent GAS infection by blocking the CD44 receptors on cells, or interfering with GAS binding. They hope to gain an understanding of why GAS turn nasty, although that may have more to do with the infected individual than the bacteria, Wessels suspects.

"There are host issues that play a big role in who’s going to get the disease," says Elaine Tuomanen, an infectious disease expert at St Jude’s Children’s Research Hospital in Memphis, Tennessee.

In the meantime, Wessel’s team hopes to develop a treatment to prevent throat infections with GAS.

"That’s certainly where the money is," comments Tuomanen.

References

  1. Cywes, C. & Wessels, M. R. Group A Streptococcus tissue invasion by CD44-mediated cell signalling. Nature, 414, 648 - 652, (2001).


TOM CLARKE | © Nature News Service
Further information:
http://www.nature.com/nsu/011206/011206-12.html

More articles from Life Sciences:

nachricht Nanoparticle Exposure Can Awaken Dormant Viruses in the Lungs
16.01.2017 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt

nachricht Cholera bacteria infect more effectively with a simple twist of shape
13.01.2017 | Princeton University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

Im Focus: Newly proposed reference datasets improve weather satellite data quality

UMD, NOAA collaboration demonstrates suitability of in-orbit datasets for weather satellite calibration

"Traffic and weather, together on the hour!" blasts your local radio station, while your smartphone knows the weather halfway across the world. A network of...

Im Focus: Repairing defects in fiber-reinforced plastics more efficiently

Fiber-reinforced plastics (FRP) are frequently used in the aeronautic and automobile industry. However, the repair of workpieces made of these composite materials is often less profitable than exchanging the part. In order to increase the lifetime of FRP parts and to make them more eco-efficient, the Laser Zentrum Hannover e.V. (LZH) and the Apodius GmbH want to combine a new measuring device for fiber layer orientation with an innovative laser-based repair process.

Defects in FRP pieces may be production or operation-related. Whether or not repair is cost-effective depends on the geometry of the defective area, the tools...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Multiregional brain on a chip

16.01.2017 | Power and Electrical Engineering

New technology enables 5-D imaging in live animals, humans

16.01.2017 | Information Technology

Researchers develop environmentally friendly soy air filter

16.01.2017 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>