Your gateway to the world of medicine
Cancer News
About Us
Health Professionals
Patients and public
Contact Us

From How Chlamydia Escapes Defenses

SARS main Acute bacterial meningitis SARS news updates  

Do You Read All Of Our Cancer Blogs?

Do You Read All Of Blogs?
Do you read all of the blogs published by Many of our bloggers are busy keeping you updated on the various health related topics. We publish the following blogs at this time.

Cancer blog: I manage the cancer blog with lots of help and support form other bloggers. Through this cancer blog my friends and I try to bring stories of hope for patients with cancer. The cancer blog often republishes important blog posts from other cancer related blogs at If you are searching for a blog that covers wide variety of cancer topics, this may be the one for you.

Breast cancer blog: Breast cancer blog is run by Emily and other bloggers and they bring you the latest stories, news and events that are related to breast cancer. Increasing awareness about breast cancer among women and in the general population is the main goal of this breast cancer blog.

Lung cancer blog: Lung cancer blog is managed by Scott with the help of other bloggers. Through this blog Scott and his friends constantly remind the readers about the dangers of smoking. It's a never-ending struggle against this miserable disease with which a social stigma of smoking is associated.

Colon cancer blog: Colon cancer blog is run by Sue and other bloggers. Sue brings a personal touch to the colon cancer blog since her mother died of colon cancer few years ago. She writes about stories, research news and advances in treatment related to colon cancer.

Prostate cancer blog: Prostate cancer is the most common cancer among American men. American Cancer Society estimates that over 230,000 new cases of prostate cancer occur in the United state every year. This important blog about prostate cancer is run by Mark and other bloggers. This blog brings news, stories, and other personal observations related to prostate cancer. publishes a diabetes watch blog and this blog is run by JoAnn other bloggers. This diabetes watch blog brings you the latest in the field of diabetes. This includes personal stories, advances in diagnosis and treatment, and other observations about diabetes. Improving awareness about diabetes is an important mission of this group.


How Chlamydia Escapes Defenses

How Chlamydia Escapes Defenses
Duke University Medical Center microbiologists have discovered that the parasitic bacteria Chlamydia escapes cellular detection and destruction by cloaking itself in droplets of fat within the cell. The scientists said that their findings represent the first example of a bacterial pathogen "mimicking" such a structure, or organelle, within a cell.

Not only do the findings suggest a novel mechanism of bacterial infection, but the new insights into Chlamydia's actions within infected cells provide rational targets for potential drugs to halt the spread of the bacteria, said the researchers. Chlamydia has been implicated in sexually transmitted infections, atherosclerosis and some forms of pneumonia.

Chlamydia is an obligate intracellular parasite that prospers within a host cell by hijacking the cell's internal machinery to survive and replicate. The bacterium lives within the cell in a protective capsule known as an inclusion. To date, it has not been clearly understood how Chlamydia has evolved to evade the cell's internal intruder alert system.

"In our experiments, we found that Chlamydia recruits lipid droplets from within the cell and stimulates the production of new droplets, which cover the surface of the inclusion," explained Yadunanda Kumar, Ph.D., a post-doctoral fellow in Duke's Department of Molecular Genetics and Microbiology. "This action of surrounding itself with lipid droplets may represent an example of organelle mimicry, where the chlamydial inclusion is protected from the cell's defenses by being perceived by the cell as just another lipid droplet."

Kumar presented the results of the Duke research Dec. 11, 2005, at the 45th annual meeting of the American Society for Cell Biology in San Francisco. The research was supported by National Institutes of Health, the Pew Foundation and the Whitehead Foundation.

When these cloaked inclusions were treated with agents known to inhibit the production of lipid droplets, the scientists were able to significantly reduce the ability of the bacterium to replicate.

"It has long been thought that lipid droplets within cells were just passive repositories of energy for the cells," said Duke microbiologist Raphael Valdivia, Ph.D., senior member of the research team. "But now we are learning that these structures appear to play important roles in lipid synthesis and transport of cholesterol throughout the cell, and cell signaling."

For their experiments, the scientists studied Chlamydia trachomatis, which is spread in humans by sexual contact and can lead to such disorders urinary tract infections, eye infections and arthritis.

Because the bacterium is an obligate parasite, scientists cannot directly manipulate its genes. So the Duke team removed genetic material from the bacterium and inserted them into yeast cells, which share a number of common structures and features with human cells.

When the scientists screened the chlamydial proteins in yeast cells, they found four specific proteins that appeared to recruit and spur the production of lipid droplets.

"Our findings provide evidence for a novel mechanism of organelle subversion where Chlamydia recruits lipid bodies and co-opts their function for survival," Valdivia said. "Chlamydia may exploit lipid droplets to acquire lipids, modulate inflammation or just for protection."

If unchecked, the inclusion will continue to grow until it fills the entire cell, causing it to explode, releasing thousands of bacteria ready to infect adjacent cells.

The findings also open the possibility of interfering with Chlamydia's ability to infect cells by disrupting the biosynthesis neutral lipids and lipid droplets. Further research will be needed to develop such therapys, since the agent the scientists used to inhibit lipid synthesis in the laboratory is not a drug that is used clinically in humans.

The scientists think that the same process may be involved in other species of Chlamydia since the genetic make-up of these bacteria has changed little over the hundreds of millions of years of its successful ability to infect eukaryotic cells.

Source: Duke Universtiy School of Medicine

Did you know?
Duke University Medical Center microbiologists have discovered that the parasitic bacteria Chlamydia escapes cellular detection and destruction by cloaking itself in droplets of fat within the cell. The scientists said that their findings represent the first example of a bacterial pathogen "mimicking" such a structure, or organelle, within a cell. How Chlamydia Escapes Defenses

SARS Main| SARS Abroad| SARS and Goverment| SARS Information in different languages| Media about SARS| Physicians resources for SARS| Reference information for SARS| Updates on SARS|

Copyright statement
The contents of this web page are protected. Legal action may follow for reproduction of materials without permission.