Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Study yields insights into pathogenic fungi—and beer

08.08.2005


Chemotherapy and organ transplantation not only take a huge toll on patients, but they can compromise the immune system and leave patients vulnerable to infections from microbes such as pathogenic fungi--the fastest-growing cause of hospital-acquired infections. Now researchers from Whitehead Institute for Biomedical Research have discovered one possible reason why these fungal microbes are such a scourge.



According to the research appearing in the August 7 online edition of the journal Nature Genetics, fungal microbes can quickly alter the appearance of their cell surfaces, their "skin," disguising themselves in order to slip past the immune system’s vigilant defenses. And, for all the world’s brewers, the study also helps explain why certain beers are cloudy and others are clear.

"It’s all about skin," says Whitehead Member Gerald Fink, who compares the fungal microbe to an M&M--a sugar coating encasing the cell’s DNA. "The skin of fungi microbes is what enables them to stick to your organs, and thus become pathogenic. It also enables the fungi to stick together, which is desirable for fermentation in beer."


The genetic core to this study is a DNA phenomenon known as tandem repeats. Here, small units of between 3 and 200 nucleotides form within a gene and repeat sometimes up to about 35 times. (Nucleotides, the building blocks of our genome, are represented by the letters A, C, T, G.) In humans, these tandem repeats received a lot of attention when the gene responsible for Huntington’s disease was discovered; a repeat of the letters CAG in a gene called IT-15 causes the condition.

These tandem repeats also occur in fungal microbes. Kevin Verstrepen, a post-doctoral researcher in Fink’s lab, decided to find out how often they occur, and what possible functions they might offer, by using baker’s yeast as a model. Verstrepen scanned the entire yeast genome with a custom computer program developed by Whitehead’s bioinformatics group. He discovered that these repeats are common throughout the yeast genome, and that more than 60 percent occur in genes that code for cell-surface, or skin, proteins. In other words, "most of these repeats somehow affect how the yeast cell interacts with the environment surrounding it," says Verstrepen.

In addition, he found that the length of these repeats varied greatly between a mother and a daughter cell. While one yeast cell might have a 20-unit repeat on a particular gene, when it divides, the new cell might have only a five-unit repeat on that same gene. And subsequently, when that cell then divides, its daughter cell might go back to 20 repeats. "It’s like an accordion," says Verstrepen. "Our study really showed how quickly and easily these repeats can recombine, altering the properties of the cell surface almost immediately."

This provides a significant clue into why fungal infections can often be so deadly. The immune system generally recognizes invaders by certain signatures on their outer coatings, such as protein conformations. However, if these fungal microbes can quickly change the shape of these proteins by changing the number of repeats in the corresponding gene, they can then manage to stay one step ahead of our body’s defenses.

"It’s important to remember," says Fink, "that these microbes have been around for billions of years. They haven’t come this far without learning how to fight off predators."

Verstrepen and his colleagues took this research a step further, focusing on a gene called FLO1, a cell-surface gene common to both baker’s yeast and pathogenic fungi. FLO1 creates the conditions that enable yeast cells to adhere to surfaces. It’s also the gene that allows pathogenic fungi to stick to host tissue. The researchers discovered a clear correlation between the number of repeats in FLO1 and the degree to which these cells could adhere to a surface. When FLO1 contained many repeats, it adhered vigorously to a plastic surface. As the number of repeats declined, so did its ability to adhere.

Fink believes that these findings show why traditional approaches to targeting drugs won’t work on fungal microbes. The features that drugs target may be exactly the ones that change so readily. "We need to target other aspects to the cell surface that don’t change," says Fink, suggesting that certain sugar molecules residing on the inside of the cell coating may be valuable targets.

The research also may help to reveal why certain strains of yeast brew better beers.

Both Verstrepen and Fink have consulted for a number of commercial brewers. "Brewers have been cultivating certain strains of yeast for hundreds of years," says Fink. "The secret of a good, fresh, clear beer--the kind that Americans tend to like--is that the yeast cells all stick together." When yeast cells don’t adhere, the beer tends to cloud up. "We now know that these tandem repeats are the molecular mechanism that yields good beer."

David Cameron | EurekAlert!
Further information:
http://www.wi.mit.edu

More articles from Studies and Analyses:

nachricht WAKE-UP provides new treatment option for stroke patients | International study led by UKE
17.05.2018 | Universitätsklinikum Hamburg-Eppendorf

nachricht First form of therapy for childhood dementia CLN2 developed
25.04.2018 | Universitätsklinikum Hamburg-Eppendorf

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

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

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

Im Focus: Entangled atoms shine in unison

A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.

The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

 
Latest News

Designer cells: artificial enzyme can activate a gene switch

22.05.2018 | Life Sciences

PR of MCC: Carbon removal from atmosphere unavoidable for 1.5 degree target

22.05.2018 | Earth Sciences

Achema 2018: New camera system monitors distillation and helps save energy

22.05.2018 | Trade Fair News

VideoLinks
Science & Research
Overview of more VideoLinks >>>