Featured Research

from universities, journals, and other organizations

Potential Key To Better Drugs To Fight Toxoplasmosis Parasite Discovered

Date:
June 24, 2008
Source:
Indiana University
Summary:
Researchers can now help explain how the parasite that causes toxoplasmosis transforms into a cyst form that resists drugs and the body's immune system, yet can emerge from its dormant state to strike when a patient's immune system is weakened. The discovery linking this stress-response mechanism to cyst formation and maintenance not only offers a possible target for new drugs, but it could also lead to a preventative vaccine -- for animals.

Discoveries by Indiana University School of Medicine scientists have opened a promising door to new drugs for toxoplasmosis and other parasites that now can evade treatments by turning dormant in the body.

Related Articles


Their findings help explain how the parasite that causes toxoplasmosis transforms into a cyst form that resists drugs and the body's immune system, yet can emerge from its dormant state to strike when a patient's immune system is weakened.

Led by William J. Sullivan Jr., Ph.D., assistant professor of pharmacology and toxicology, and Ronald C. Wek, Ph.D., professor of biochemistry and molecular biology, the research team found a cellular signaling system that takes hold when the parasite is stressed, enabling it to transform into the cyst surrounded by a protective barrier.

The signaling system identified by the IU team could serve as a target to block the transformation into the cyst form or to attack the parasite while in the cyst form. Their report was published in the June 13 issue of the Journal of Biological Chemistry.

The Toxoplasma gondii parasite converts from an active state to the inactive cyst state when it is stressed, for example, by heat from fever. Stress response mechanisms have been well studied in yeast and other organisms, but the pathways used by the toxoplasmosis parasite had not been determined.

"We found a cellular signal that appears to put the parasite to sleep, which in turn tells us something new about how opportunistic pathogens such as Toxoplasma awaken to cause disease during immunosuppression," said Dr. Sullivan.

An estimated 60 million people in the United States are infected with the toxoplasmosis parasite, but for most infection produces flu-like symptoms or no symptoms at all. However, for people with immune system problems -- such as those undergoing chemotherapy or people with AIDS -- the disease can cause serious effects including lung problems, blurred vision and seizures. Also, infants born to mothers who are infected during or shortly before pregnancy are at risk for severe complications, miscarriages or stillbirths.

Medications to treat Toxoplasma gondii are effective but too toxic for extended use, and they don't affect the cyst form, said Dr. Sullivan.

"A healthy immune system can keep this parasite in the cyst state. Without a healthy immune system, this organism can run rampant," said Dr. Sullivan. "This can be a very serious problem for people with AIDS."

The discovery linking this stress-response mechanism to cyst formation and maintenance not only offers a possible target for new drugs, but it could also lead to a preventative vaccine -- for animals.

The Toxoplasma gondii parasite can infect most animals and birds, but it reproduces in cats, which can shed the parasite in their feces. Humans can be infected through contact with the infected feces or litter. People can also become infected by consuming undercooked meat.

A vaccine to prevent infection in cats and livestock could prevent a significant proportion of human infections, Dr. Sullivan said.

The research of Drs. Sullivan and Wek is supported by the National Institutes of Health and the American Heart Association.


Story Source:

The above story is based on materials provided by Indiana University. Note: Materials may be edited for content and length.


Cite This Page:

Indiana University. "Potential Key To Better Drugs To Fight Toxoplasmosis Parasite Discovered." ScienceDaily. ScienceDaily, 24 June 2008. <www.sciencedaily.com/releases/2008/06/080618133713.htm>.
Indiana University. (2008, June 24). Potential Key To Better Drugs To Fight Toxoplasmosis Parasite Discovered. ScienceDaily. Retrieved October 24, 2014 from www.sciencedaily.com/releases/2008/06/080618133713.htm
Indiana University. "Potential Key To Better Drugs To Fight Toxoplasmosis Parasite Discovered." ScienceDaily. www.sciencedaily.com/releases/2008/06/080618133713.htm (accessed October 24, 2014).

Share This



More Plants & Animals News

Friday, October 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Reuters - Innovations Video Online (Oct. 24, 2014) Miniature deep sea animals discovered off the Australian coast almost three decades ago are puzzling scientists, who say the organisms have proved impossible to categorise. Academics at the Natural History of Denmark have appealed to the world scientific community for help, saying that further information on Dendrogramma enigmatica and Dendrogramma discoides could answer key evolutionary questions. Jim Drury has more. Video provided by Reuters
Powered by NewsLook.com
Black Bear Cub Goes Sunday Shopping

Black Bear Cub Goes Sunday Shopping

Reuters - Light News Video Online (Oct. 23, 2014) Price check on honey? Bear cub startles Oregon drugstore shoppers. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Dances With Wolves in China's Wild West

Dances With Wolves in China's Wild West

AFP (Oct. 23, 2014) One man is on a mission to boost the population of wolves in China's violence-wracked far west. The animal - symbol of the Uighur minority there - is under threat with a massive human resettlement program in the region. Duration: 00:41 Video provided by AFP
Powered by NewsLook.com
Breakfast Debate: To Eat Or Not To Eat?

Breakfast Debate: To Eat Or Not To Eat?

Newsy (Oct. 23, 2014) Conflicting studies published in the same week re-ignited the debate over whether we should be eating breakfast. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins