Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Leading cause of US food-borne illness makes its own pathway through cells

15.01.2007
Yale researchers now have some answers about how the bacterium that is the leading cause of food-borne illness in the United States enters cells of the gut and avoids detection and destruction, according to a presentation at the annual meeting of the American Society for Cell Biology in San Diego in December.

While scientists are just beginning to answer basic questions about how Campylobacter jejuni (campylobacter) causes infection, Robert Watson, a graduate student in the Section of Microbial Pathogenesis at Yale University School of Medicine worked out a better way to study the bacteria and reported that it takes an uncommon path as it infects cells.

Since the intestinal lining cells that campylobacter infects do not normally take up bacteria -- or any particles as large as bacteria -- Watson and his advisor, Jorge Galán, the Lucille P Markey Professor of Microbiology and Cell Biology, set out to investigate the path of infection through cells. They found that campylobacter apparently enters into the endocytic pathway that cells use to recycle molecules from their surface. It then quickly diverts its path, creating its own intracellular network of campylobacter-filled vacuoles, or cellular pockets, that make their way toward the nucleus, and finally locate near the cell's transportation hub, the Golgi apparatus.

"It's been known for over two decades that campylobacter can enter intestinal epithelial cells -- but until now no one could show how it was taken up or where it localized. That suggested it had evolved a special mechanism for uptake," said Watson. "Campylobacter seems to have found a special access to these cells and established its own intracellular niche."

... more about:
»Campylobacter »Galán »Watson

The U.S. Centers for Disease Control and Prevention estimates that "campylobacteriosis," one of the most common causes of diarrhea worldwide, strikes 2.4 million Americans a year. Most sufferers recover after a few unpleasant days, but it can be life threatening to those with compromised immune systems including individuals with AIDS. In addition, a rare but serious complication of campylobacter infection is triggering of the autoimmune disorder, Guillain-Barré paralysis.

"Chicken has been a notorious as a source of campylobacter," said Watson. "While the public has been aware of salmonella as a contaminant, the January 2007 issue of Consumer Reports highlights the increase in campylobacter as a problem. Their nationwide analysis of fresh, marketed chicken showed that as much as 80 percent of the meat they tested harbored campylobacter."

Usually, material entering the cell moves to compartments called lysosomes, where an acidic mix of enzymes breaks it down. By monitoring markers for this entry pathway, Watson and Galán could watch as the microbe infected a host cell, briefly associated with the early marker protein EEA-1, and then with the late marker Lamp-1.

"Although the marker proteins indicated that campylobacter trafficked to conventional lysosomes, information from traceable dyes indicated something different," said Watson. While the dyes passed through the endocytic pathway and localized with other material in lysosomes, surprisingly, the dyes did not enter the vacuoles containing campylobacter -- these bacteria had left the conventional pathway.

Watson and Galán also looked at the roles of two Rab GTPases, proteins involved in the maturation of the recycling compartments. These and other experiments gave additional evidence that campylobacter leaves the normal endocytic pathway early and that the separated campylobacter vacuoles move near to the nucleus where they become closely associated with the Golgi apparatus.

"Seeing the path these bacteria follow gives us new perspective for understanding infection and devising ways to combat it," said Galán. As the next step in understanding campylobacter, Watson and Galán are continuing and expanding the work to include studies in special strains of mice that are infected by, and harbor the bacteria but do not show the acute symptoms of infection.

Janet Rettig Emanuel | EurekAlert!
Further information:
http://www.yale.edu

Further reports about: Campylobacter Galán Watson

More articles from Life Sciences:

nachricht For a chimpanzee, one good turn deserves another
27.06.2017 | Max-Planck-Institut für Mathematik in den Naturwissenschaften (MPIMIS)

nachricht New method to rapidly map the 'social networks' of proteins
27.06.2017 | Salk Institute

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Touch Displays WAY-AX and WAY-DX by WayCon

27.06.2017 | Power and Electrical Engineering

Drones that drive

27.06.2017 | Information Technology

Ultra-compact phase modulators based on graphene plasmons

27.06.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>