Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Wisconsin scientists discover a master key to microbes’ pathogenic lifestyles

28.04.2006
For some microbes, the transformation from a benign lifestyle in the soil to that of a potentially deadly human pathogen is just a breath away.

Inhaled into the lungs of a mammal, spores from a class of six related soil molds found around the world encounter a new, warmer environment. And as soon as they do, they rapidly shift gears and assume the guise of pathogenic yeast, causing such serious and sometimes deadly afflictions as blastomycosis and histoplasmosis.

But how these usually bucolic fungi undergo such a transformation to become serious pathogens has always been a puzzle. Now, however, a team of scientists from the University of Wisconsin School of Medicine and Public Health reports the discovery of a master molecular sensor embedded in the spores of the fungi that triggers the transformation. The finding is reported in the April 28 edition of the journal Science.

The discovery could lead to new treatments, and possibly vaccines for the diseases caused by these Jekyll and Hyde microbes, says Bruce Klein, a UW-Madison professor of pediatrics, internal medicine and medical microbiology and immunology, and the senior author of the new study.

"These microbes have to undergo an extreme makeover to survive in a host," says Klein, an authority on fungal diseases. "The million dollar question is was what controls this change? "

Klein and colleagues Julie C. Nemecek and Marcel Wuthrich identified a molecular sensor that is conserved in these six related dimorphic fungi found worldwide. The sensor, says Klein, is like an antenna situated in the membrane of the fungi’s spores. It senses temperature, and when a spore finds itself at a comfortable 37 degrees Celsius, the body temperature of a human or other animal, it kick starts a genetic program that transforms the fungi into pathogenic yeasts.

"This is a global regulator that sends signals down a molecular chain of command and governs a series of vital genetic programs," Klein explains. "It leads to changes in the organism’s metabolism, cell shape, cell wall composition, and changes in virulence gene expressions."

These changes, according to Klein, are really a survival program for the microbe, conferring resistance to the host’s immune responses.

The diseases caused by the fungi can be especially serious for immune compromised individuals, and some human populations seem to be more at risk for acquiring the infections. For example, U.S. soldiers who train in the American Southwest tend to be susceptible to coccidiomycosis because the organism that causes it is endemic to the region. One in three of those who train there acquire the disease, considered to be the second most common fungal infection in the United States. Of those infected, 25 percent contract pneumonia.

Histoplasmosis, a disease caused by the fungus Histoplasma capsulatum, infects as much as 80 percent of the population where the organism is endemic, including much of the eastern and central United States. It is also widespread in South America and Africa. In most instances, the infection prompts only mild symptoms. Untreated, however, it can be fatal. What’s more, the microbe can lay dormant in an infected host for years.

"All of these organisms exhibit this property of latency," says Klein. "They can remain dormant until immune defenses are lowered. It’s a significant medical problem in endemic regions."

The discovery of the switch that governs dimorphism and virulence in this prevalent class of fungi provides a target for new therapeutic agents and might even help underpin a vaccine able to thwart infection entirely, according to Klein.

"This could lead to therapeutics, better treatment for this class of diseases," Klein explains. "And with this finding, vaccines might now be possible. That’s a strategy with promise."

The discovery of a master switch in related but diverse and geographically widespread class of fungi is an indication that it was acquired from a common ancestor deep in evolutionary history. The feature is a common mechanism used by the different organisms to adapt to a new environment: the lungs of animals.

"It is a story of how organisms are challenged in a new environment," says Klein. "They have to make themselves over so they can survive."

Bruce Klein | EurekAlert!
Further information:
http://www.wisc.edu

More articles from Life Sciences:

nachricht Multi-institutional collaboration uncovers how molecular machines assemble
02.12.2016 | Salk Institute

nachricht Fertilized egg cells trigger and monitor loss of sperm’s epigenetic memory
02.12.2016 | IMBA - Institut für Molekulare Biotechnologie der Österreichischen Akademie der Wissenschaften GmbH

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>