Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


U of T research sheds new light on mysterious fungus that has major health consequences


Researchers at the University of Toronto examined fungi in the mucus of patients with cystic fibrosis and discovered how one particularly cunning fungal species has evolved to defend itself against neighbouring bacteria.

A regular resident of our microbiome - and especially ubiquitous in the lungs of cystic fibrosis patients -the Candida albicans fungus is an "opportunistic pathogen." This means it usually leaves us alone, but can turn against us if our immune system becomes compromised.

Candida albicans in its round and filamentous (stringy) shapes.

Credit: University of Toronto

In fact, this fungus is among the most common causes of bloodstream infections, such as sepsis. As the population living with weakened immune systems has risen substantially over the past two decades - people living with HIV, having organ transplants or undergoing cancer chemotherapy are some examples - opportunistic fungal pathogens like this one have become an even greater threat. This is especially alarming considering we don't have any surefire anti-fungal drug to stop them.

"Fungi have a staggering impact on human health, infecting billions of people around the world and killing 1.5 million every year - that's in the range of tuberculosis and malaria," says Leah Cowen, lead researcher on the study, University of Toronto Molecular Genetics professor and Canada Research Chair in Microbial Genomics and Infectious Disease. "And yet, they are underappreciated and not well understood."

Candida albicans is a particularly wily fungus. Its signature maneuver is shapeshifting - it can morph from a round, single-celled yeast into a long stringy structure, allowing it to adapt to different environments and making it exceptionally harmful. For this study, researchers analyzed 89 mucus samples from 28 cystic fibrosis patients, using both high-throughput genetic sequencing as well as culture-based analysis. Candida albicans was predictably prevalent.

What surprised the researchers, however, was that some of this fungi began shifting into its stringy shape without any environmental cue - usually this transformation (called filamentation) doesn't happen spontaneously, but is triggered by the presence of certain substances, such as blood.

To see if there could be a genetic explanation, the researchers sequenced the genomes of these samples and found a common denominator. All but one had genetic mutations in a gene known to repress the change shape - called NRG1.

"This was a smoking gun," says Cowen. "This gene makes a protein that stops filamentation - like a brake. Because of these genetic mutations, the fungi lost this brake and were not able to stop these long strings from forming."

To find out why certain strains of this fungus would have developed this genetic variation, researchers looked to neighbouring bacteria. As part of an ongoing battle between microbes, certain bacteria, which are also found in cystic fibrosis patients, secrete molecules preventing the fungus from changing into its stringy shape.

The researchers tried exposing the mutated fungus to these bacterial rivals. Instead of responding to the bacterial signals, the fungus kept to its stringy form. The researchers believe these fungi have evolved to counter the tactics of their bacterial rivals.

"We think the interaction between bacteria and fungus drove this," says Cowen. "Usually losing control isn't a very good thing, but in this case it may be a great defense mechanism for Candida. These fungi have essentially learned to ignore the bacteria."

This study was published today in the journal PLOS Pathogens. It was part of a large interdisciplinary Canadian Institutes of Health Research grant, involving researchers across disciplines - clinicians, molecular biologists, evolutionary biologists and bioinformaticians collaborated on a variety of microbiome-focused studies.

Cowen is continuing research into the impact of fungal pathogens in cystic fibrosis patients, who are unable to clear microbes from their airways and suffer reduced lung function as a result. We still have no cure for this fatal genetic disease. She is also seeking to better understand the role of fungi in variety of other conditions.

Media Contact

Carolyn Morris


Carolyn Morris | EurekAlert!

More articles from Health and Medicine:

nachricht NIH scientists describe potential antibody treatment for multidrug-resistant K. pneumoniae
14.03.2018 | NIH/National Institute of Allergy and Infectious Diseases

nachricht Researchers identify key step in viral replication
13.03.2018 | University of Pittsburgh Schools of the Health Sciences

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

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

Im Focus: Locomotion control with photopigments

Researchers from Göttingen University discover additional function of opsins

Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...

Im Focus: Surveying the Arctic: Tracking down carbon particles

Researchers embark on aerial campaign over Northeast Greenland

On 15 March, the AWI research aeroplane Polar 5 will depart for Greenland. Concentrating on the furthest northeast region of the island, an international team...

Im Focus: Unique Insights into the Antarctic Ice Shelf System

Data collected on ocean-ice interactions in the little-researched regions of the far south

The world’s second-largest ice shelf was the destination for a Polarstern expedition that ended in Punta Arenas, Chile on 14th March 2018. Oceanographers from...

Im Focus: ILA 2018: Laser alternative to hexavalent chromium coating

At the 2018 ILA Berlin Air Show from April 25–29, the Fraunhofer Institute for Laser Technology ILT is showcasing extreme high-speed Laser Material Deposition (EHLA): A video documents how for metal components that are highly loaded, EHLA has already proved itself as an alternative to hard chrome plating, which is now allowed only under special conditions.

When the EU restricted the use of hexavalent chromium compounds to special applications requiring authorization, the move prompted a rethink in the surface...

Im Focus: Radar for navigation support from autonomous flying drones

At the ILA Berlin, hall 4, booth 202, Fraunhofer FHR will present two radar sensors for navigation support of drones. The sensors are valuable components in the implementation of autonomous flying drones: they function as obstacle detectors to prevent collisions. Radar sensors also operate reliably in restricted visibility, e.g. in foggy or dusty conditions. Due to their ability to measure distances with high precision, the radar sensors can also be used as altimeters when other sources of information such as barometers or GPS are not available or cannot operate optimally.

Drones play an increasingly important role in the area of logistics and services. Well-known logistic companies place great hope in these compact, aerial...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

International Tinnitus Conference of the Tinnitus Research Initiative in Regensburg

13.03.2018 | Event News

International Virtual Reality Conference “IEEE VR 2018” comes to Reutlingen, Germany

08.03.2018 | Event News

Latest News

Development and Fast Analysis of 3D Printed HF Components

19.03.2018 | Trade Fair News

In monogamous species, a compatible partner is more important than an ornamented one

19.03.2018 | Life Sciences

Signaling Pathways to the Nucleus

19.03.2018 | Life Sciences

Science & Research
Overview of more VideoLinks >>>