Featured Research

from universities, journals, and other organizations

Tiny Fungi May Have Sex While Infecting Humans

Date:
November 3, 2008
Source:
Duke University Medical Center
Summary:
A fungus called microsporidia that causes chronic diarrhea in AIDS patients, organ transplant recipients and travelers has been identified as a member of the family of fungi that have been discovered to reproduce sexually. Scientists have proven that microsporidia are true fungi and that this species most likely undergoes a form of sexual reproduction during infection of humans and other host animals.

Scanning electron micrograph of a microsporidian spore with an extruded polar tubule inserted into a eukaryotic cell. The spore injects the infective sporoplasms through its polar tubule.
Credit: CDC/NCID/DPD Parasite Image Library

A fungus called microsporidia that causes chronic diarrhea in AIDS patients, organ transplant recipients and travelers has been identified as a member of the family of fungi that have been discovered to reproduce sexually. A team at Duke University Medical Center has proven that microsporidia are true fungi and that this species most likely undergoes a form of sexual reproduction during infection of humans and other host animals.

Related Articles


The findings could help develop effective treatments against these common global pathogens and may help explain their most virulent attacks.

"Microsporidian infections are hard to treat because until now we haven't known a lot about this common pathogen," says Soo Chan Lee, Ph.D., lead author and a postdoctoral researcher in the Duke Department of Molecular Genetics and Microbiology. "Up to 50 percent of AIDS patients have microsporidial infections and develop chronic diarrhea. These infections are also detected in patients with traveler's diarrhea, and also in children, organ transplant recipients and the elderly."

Of the 1200 species of microsporidia, more than a dozen infect humans. Their identity had been obscured because these tiny fungi cannot live outside of an infected host cell and they have a small number of genes which are rapidly evolving.

The Duke scientists used two genetic studies to show that microsporidia apparently evolved from sexual fungi and are closely related to the zygomycete fungus in particular.

They found that microsporidia share 33 genes out of 2,000 with zygomycetes which the microsporidia did not share with other fungi. This genomic signature also shows that microsporidia and zygomycetes likely shared a common ancestor and are more distantly related to other known fungal lineages.

In addition, these two types of fungi have the same sex-locus genes – and in the same order – in their DNA. Other genes involved in sexual reproduction are also present. The findings suggest that microsporidia may have a genetically controlled sexual cycle, and may be undergoing sexual reproduction while they infect the host, Lee said.

Lee said the next step is to explore the sexual reproduction of these species, which may cause more severe (more virulent) infections because they use the host's cellular environment and machinery as a safe haven in which to reproduce.

"These studies resolve the enigma of the evolutionary origins and proper placement of this highly successful group of pathogens, and provide better approaches to their experimental study," said senior author Joseph Heitman, M.D., Ph.D., director of the Center for Microbial Pathogenesis and director of the Duke University Program in Genetics and Genomics.

The team will pursue further studies with Duke genetic researchers Raphael Valdivia, Ph.D., and Alejandro Aballay, Ph.D., using cultured cells and C. elegans, a worm that researchers recently found is a natural host for microsporidia. "Using this roundworm may prove to be a useful way to study microsporidia genetics in a living creature," Heitman said.

This work was published online in the Oct. 30 edition of Current Biology, and was supported by grants from the National Institute of Allergy and Infectious Diseases of the National Institutes of Health, and by the Canadian Institutes for Health Research.

Other authors on this study include Nicolas Corradi and Patrick J. Keeling of the Canadian Institute for Advanced Research, Department of Botany, University of British Columbia – Vancouver; Edmond J. Byrnes III of the Duke Department of Molecular Genetics and Microbiology; Santiago Torres-Martinez of the Departamento de Genetica y Microbiologia, Facultad de Biologia, Universidad de Murcia, Spain; and Fred S. Dietrich of Duke Molecular Genetics and Microbiology and the Duke Institute for Genome Sciences and Policy.


Story Source:

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


Journal Reference:

  1. Lee et al. Microsporidia Evolved from Ancestral Sexual Fungi. Current Biology, 2008; DOI: 10.1016/j.cub.2008.09.030

Cite This Page:

Duke University Medical Center. "Tiny Fungi May Have Sex While Infecting Humans." ScienceDaily. ScienceDaily, 3 November 2008. <www.sciencedaily.com/releases/2008/10/081030123831.htm>.
Duke University Medical Center. (2008, November 3). Tiny Fungi May Have Sex While Infecting Humans. ScienceDaily. Retrieved October 24, 2014 from www.sciencedaily.com/releases/2008/10/081030123831.htm
Duke University Medical Center. "Tiny Fungi May Have Sex While Infecting Humans." ScienceDaily. www.sciencedaily.com/releases/2008/10/081030123831.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