XML Feed for RxPG News   Add RxPG News Headlines to My Yahoo!   Javascript Syndication for RxPG News

Research Health World General
 
  Home
 
 Latest Research
 Cancer
 Psychiatry
 Genetics
 Surgery
 Aging
 Ophthalmology
 Gynaecology
 Neurosciences
 Pharmacology
 Cardiology
 Obstetrics
 Infectious Diseases
 Respiratory Medicine
 Pathology
 Endocrinology
 Immunology
 Nephrology
 Gastroenterology
 Biotechnology
 Radiology
 Dermatology
 Microbiology
  Virology
  Bacteriology
   Salmonella
 Haematology
 Dental
 ENT
 Environment
 Embryology
 Orthopedics
 Metabolism
 Anaethesia
 Paediatrics
 Public Health
 Urology
 Musculoskeletal
 Clinical Trials
 Physiology
 Biochemistry
 Cytology
 Traumatology
 Rheumatology
 
 Medical News
 Health
 Opinion
 Healthcare
 Professionals
 Launch
 Awards & Prizes
 
 Careers
 Medical
 Nursing
 Dental
 
 Special Topics
 Euthanasia
 Ethics
 Evolution
 Odd Medical News
 Feature
 
 World News
 Tsunami
 Epidemics
 Climate
 Business
 
 India
Search

Last Updated: Nov 18, 2006 - 12:32:53 PM

Bacteriology Channel
subscribe to Bacteriology newsletter

Latest Research : Microbiology : Bacteriology

   DISCUSS   |   EMAIL   |   PRINT
Understanding how Rickettsia conorii interacts with host cells
Dec 17, 2005 - 3:41:00 PM, Reviewed by: Dr. Priya Saxena

�We found that Ku70 interacts with a bacterial protein called rOmpB, which is present on the surface of Rickettsia bacteria. The mechanism underlying this interaction remains unclear, so we are now investigating how rOmpB, expressed by R. conorii, interacts with Ku70 and allows bacterial entry.�

 
New research by a team of scientists in France and the United States has identified both the bacterial and host receptor proteins that enable Rickettsia conorii, the Mediterranean spotted fever pathogen to enter cells. Understanding how this bacterium interacts with the cells of its host could lead to new therapeutic strategies for diseases caused by related pathogens, including Rocky Mountain spotted fever and typhus.

Pascale Cossart, an HHMI international research scholar at the Pasteur Institute in Paris, together with her postdoctoral fellow Juan Martinez and collaborators in Paris and at Case Western Reserve University in Cleveland, Ohio, has identified the first receptor for a Rickettsial bacterium. Their findings will be reported in the December 16, 2005, issue of the journal Cell.

Rickettsial bacteria are transmitted by fleas, ticks, and lice to humans and other mammals, where they can cause dangerous and sometimes fatal infections. There are two types of Rickettsial pathogens�the spotted fever group, which includes the Rickettsia conorii bacteria studied by Cossart and her colleagues, and the typhus group. Both must live inside cells to survive. Rickettsia have been classified by the National Institute of Allergy and Infectious Diseases (NIAID) as agents with potential for use as tools for bioterrorism.

Mediterranean spotted fever is transmitted by a dog tick. The symptoms are generally mild and respond to antibiotics that shorten the course of the disease. But serious complications occur as much as 10 percent of the time, usually in patients who are elderly or who have some other underlying disease. Left untreated, Mediterranean spotted fever can be deadly.

Cossart and her team demonstrated that the Ku70 protein on the surface of host cells is critical for R. conorii to enter the cell, making it the first Rickettsial receptor ever identified. �This receptor is a subunit of a protein complex present mainly in the nucleus, but also in the cell cytoplasm and at the cell membrane,� said Cossart. �We have thus used several approaches to establish our findings definitively.� Ku70 is probably not the only receptor involved in bacterial entry, she noted.

The researchers found that R. conorii specifically binds to Ku70, and that binding and recruitment of Ku70 at the surface of the host cell are important events in R. conorii's invasion of mammalian cells. In addition, since Ku70 has previously been shown to control cell death, the new findings suggest that Rickettsia, which�like several other intracellular parasites�prevent cell death in order to multiply inside living cells, may also use this property of their receptor for a succesful infection.

�We found that Ku70 interacts with a bacterial protein called rOmpB, which is present on the surface of Rickettsia bacteria,� Cossart said. �The mechanism underlying this interaction remains unclear, so we are now investigating how rOmpB, expressed by R. conorii, interacts with Ku70 and allows bacterial entry.�

Her team has already shown that Ku70 has to be present in certain well-organized regions of the cell membrane called rafts, and that the protein modifier called ubiquitin modifies Ku70 as soon as the bacteria interact with it. This step is critical for cell entry. �Whether other Rickettsia and other pathogens use Ku70 as a receptor is still unknown,� Cossart said.
 

- Their findings will be reported in the December 16, 2005, issue of the journal Cell.
 

www.hhmi.org

 
Subscribe to Bacteriology Newsletter
E-mail Address:

 

Howard Hughes Medical Institute - A philanthropy serving society through biomedical research and science education.

Related Bacteriology News

Gut Bacteria Cospeciating with Plataspid stinkbug
An infectious agent of deception, exposed through proteomics
Gram positive bacterial membrane mystery solved
Salmonella bacteria use RNA to assess and adjust magnesium levels
How deadly toxin botulinum neurotoxin A hijacks cells
String Test: Effective and Inexpensive Method for Detecting Helicobacter pylori
Scientists develop biosensor to detect E. Coli bacteria
Found - bacteria with strange magnetic personality
Student discovers protein in yoghurt that fights E. coli
Slugs May Spread E. coli to Salad Vegetables


For any corrections of factual information, to contact the editors or to send any medical news or health news press releases, use feedback form

Top of Page

 

© Copyright 2004 onwards by RxPG Medical Solutions Private Limited
Contact Us