Featured Research

from universities, journals, and other organizations

Gene That Governs Toxin Production In Deadly Mold Found

Date:
April 13, 2007
Source:
University of Wisconsin-Madison
Summary:
For the growing number of people with diminished immune systems -- cancer patients, transplant recipients, those with HIV/AIDS -- infection by a ubiquitous mold known as Aspergillus fumigatus can be a death sentence.

For the growing number of people with diminished immune systems - cancer patients, transplant recipients, those with HIV/AIDS - infection by a ubiquitous mold known as Aspergillus fumigatus can be a death sentence.

The fungus, which is found in the soil, on plant debris and indoor air, is easily managed by the healthy immune system. But as medical advances contribute to a growing population of people whose immune systems are weakened by disease or treatment, the opportunistic fungus poses a serious risk.

Now, however, scientists may have found a master switch, an όber gene, that seems to control the mold's ability to make poison. The new finding was reported April 12 in the journal Public Library of Science Pathogens by a team led by Nancy P. Keller, a biologist from the University of Wisconsin-Madison.

"There is a growing problem with medical fungi in the United States," says Keller, a UW-Madison professor of plant pathology and medical microbiology. "Aspergillus fumigatus is among the most important."

Like many fungi, Aspergillus fumigatus makes a variety of poisons, presumably to give the microbe a competitive advantage in the environments it inhabits. In humans with suppressed immune systems, the mold can cause a number of diseases with mortality rates of 60 percent or more.

"The infection can be treated, but not easily," Keller explains. "Once an immunocompromised individual gets any fungal disease, it's pretty hard to treat, and the treatments themselves are often toxic. There is a 60-90 percent mortality rate with invasive aspergillosis."

Thus, knowing how the fungus makes its chemical arsenal is important and opens an avenue to devising novel treatments that can disarm the pathogen before it does its dirty work.

In fungi, there are typically many genes at work making toxins and other chemical metabolites. The genes tend to be clustered in groups on the organism's genome. In Aspergillus fumigatus, there are as many as 22 such gene groupings.

How those posses of genes are triggered and governed, however, has been a mystery. But now Keller's group has found that a key gene known as LaeA controls at least half of those toxin-producing gene clusters, suggesting there may be a way to modulate the virulence of the deadly microbe.

"We now have a very good idea that (the gene) is central to the toxic nature of the fungus," Keller says.

The LaeA gene, she believes, is like a maestro, directing the mold's toxin-producing genes in an orchestrated chorus that, in the right host, can be fatal.

Knowing this, Keller explains, "suggests that if you can find a way to regulate the activity of LeaA you might have a novel target" for new therapies to treat Aspergillus fumigatus infection.

"The gene is not expressed all the time, which means there must be a signal that says 'turn me on.'"

Removing the gene from the equation, she says, may cripple the microbe's ability to infect and sicken people.

"The loss of LaeA results in a great decrease in the repertoire of secondary metabolites, which appears to impact the infection process," making the gene an ideal prospect for new ways to fight infection.

The new work was supported by grants from the National Institutes of Health. In addition to Keller, authors of the new PloS Pathogens manuscript include Robyn M. Perrin and Jin Woo Bok of UW-Madison; Natalie D. Fedorova and William C. Nierman of the Institute for Genomic Research in Rockville, Md.; Robert A. Cramer of Duke University Medical Center; and H. Stanley Kim of Korea University Medical College, Seoul, Korea.


Story Source:

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


Cite This Page:

University of Wisconsin-Madison. "Gene That Governs Toxin Production In Deadly Mold Found." ScienceDaily. ScienceDaily, 13 April 2007. <www.sciencedaily.com/releases/2007/04/070412211403.htm>.
University of Wisconsin-Madison. (2007, April 13). Gene That Governs Toxin Production In Deadly Mold Found. ScienceDaily. Retrieved April 21, 2014 from www.sciencedaily.com/releases/2007/04/070412211403.htm
University of Wisconsin-Madison. "Gene That Governs Toxin Production In Deadly Mold Found." ScienceDaily. www.sciencedaily.com/releases/2007/04/070412211403.htm (accessed April 21, 2014).

Share This



More Plants & Animals News

Monday, April 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Breakfast Foods Are Getting Pricier

Breakfast Foods Are Getting Pricier

AP (Apr. 21, 2014) — Breakfast is now being served with a side of sticker shock. The cost of morning staples like bacon, coffee and orange juice is on the rise because of global supply problems. (April 21) Video provided by AP
Powered by NewsLook.com
Mich. Boy Unearths 10,000-Year-Old Mastodon Tooth

Mich. Boy Unearths 10,000-Year-Old Mastodon Tooth

Newsy (Apr. 20, 2014) — A 9-year-old Michigan boy was exploring a creek when he came across a 10,000-year-old tooth from a prehistoric mastodon. Video provided by Newsy
Powered by NewsLook.com
Vermont Goat Meat Gives Refugees Taste of Home

Vermont Goat Meat Gives Refugees Taste of Home

AP (Apr. 18, 2014) — Dairy farmers and ethnic groups in Vermont are both benefiting from a unique collaborative effort that's feeding a growing need for fresh and affordable goat meat. (April 18) Video provided by AP
Powered by NewsLook.com
Man Claims He Found Loch Ness Monster With... Apple Maps?

Man Claims He Found Loch Ness Monster With... Apple Maps?

Newsy (Apr. 18, 2014) — Andy Dixon showed the Daily Mail a screenshot of what he believes to be the mythical beast swimming just below the lake's surface. 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:
from the past week

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