Researchers gain insight into the biology of a deadly fungus

Researchers at the University of Massachusetts Amherst have gained new insight into the biological processes of a chytrid fungus responsible for a deadly skin infection that is destroying the frog populations worldwide.

Led by cell biologist Lillian Fritz-Laylin, the team describes in an article published on February 8 Current biology how the action networks of Batrachochytrium dendrobatidis (Bd) also serve as an “evolutionary Rosetta Stone”, revealing the loss of cytoskeletal complexity in the fungal kingdom.

“Fungi and animals look so different, but they are actually very closely related,” says Fritz-Laylin, whose laboratory studies how cells move, which is an important activity in the progression and prevention of many human diseases. “This project, the work of Sarah Prostak in my lab, shows that fungi probably had early cells that looked like our cells and that could crawl around like our cells.”

Chytrids, including Bd, include more than 1,000 species of fungi deep in the phylogenetic or evolutionary tree. The researchers use chytrids, which are characteristic features of animal cells lost in yeast and other fungi, to investigate the evolution of actin cytoskeleton, which helps the cells maintain their shape and organization and move, distribution and other important functions. to perform.

Prostak, a research fellow in Fritz-Laylin’s laboratory, is the lead author of the paper, which she initially wrote as her undergraduate honors biology thesis. Other authors include Margaret Titus, professor of genetics, cell biology and development at the University of Minnesota, and Kristyn Robinson, a UMass Amherst Ph.D. candidate in Fritz-Laylin’s laboratory.

“Bd is more closely related to animal cells than fungi that are more typically studied, so it can tell us a lot about the animal sex and the fungal lineage and can also give a lot of insight into human action networks,” says Prostak. “We can use it to study animal-like regulation in a similar system rather than to study it in animal cells, which is very complicated because animal cells have so many action regulators.”

The research team used a combination of genomics and fluorescence microscopy to show that the actin cytoskeleton of chytride contains characteristics of both animal cells and yeast. “How these complex actin-regulating networks have been developed and diversified remains the most important questions in evolutionary as well as cell biology,” the article reads.

The biologists examined the two developmental stages in Bd’s life cycle. In the first phase, Bd soups swim with a flagellum and build actin structures similar to those of animal cells, including sham legs that propel the organisms forward. In the reproductive stage, Bd sporangia co-produce stock shells, as well as stock stains, which are similar to those of yeast.

The disease chytridiomycosis, caused by Bd, destroys the skin of frogs, frogs and other amphibians, which eventually leads to heart failure after fluid regulation is discarded. This disease is attributed to large losses of biodiversity, including decades of perceived population declines and extinctions over the past 50 years, although exactly how many species have been affected by this disease.

The UMass Amherst biologists say Bd’s actin structures they observed are likely to play important roles in the cause of the disease. “This model suggests that stock networks underlie the mobility and rapid growth that are key to the pathology and pathogenicity of Bd,” the article concludes.

Prostak, an animal lover attracted by Fritz-Laylin’s laboratory because of its focus on pathogens, hopes that their research that promotes knowledge about Bd will lead to measures that delay the deadly damage of chytridiomycosis.

“The basic biology of Bd selection will hopefully provide insight into disease mitigation in the future,” says Prostak.