When Aaron Mitchell took an undergraduate genetics course at Carnegie Mellon University in 1975, he was hooked. “I thought the subject was the best thing I had ever heard in my life,” says Mitchell, now a professor at the University of Georgia and recipient of this year’s George W. Biddle Award. This course led to a career-long fascination with yeast genetics where he developed many of the important tools that entomologists used to study yeast. Candida albicanswhich forms biofilms on human surfaces or medical devices and causes opportunistic infections, while at Columbia University, Carnegie Mellon, and the University of Georgia.
Inspired by a genetics course, Mitchell began her research career in 2017. Saccharomyces cerevisiae As an undergraduate and worked on biology for nearly 20 years, studying the regulation of meiosis and pH sensing. When Mitchell first started reading. S. cerevisiaethere were not many genetic tools available and scientists were just beginning to understand how to modify yeast with DNA.
Developing genetic tools for C. albicans
Mitchell was interested C. albicans When he was director of the Cold Spring Harbor course on yeast genetics in 1992 and was studying how C. albicans Since then biofilms. Because he saw how S. cerevisiae As a model organism grew over the years, he wanted to do the same for it. C. albicans: Develop tools to study it, share reagents, and strengthen the use of genetics in the mycology community.
As one of the makers C. albicans Genetically viable, Mitchell developed a gene disruption method based on short regions of homology. URA3 Gene cassettes to generate unmarked homozygous mutants that have both been widely used. He produced one. C. albicans transcription factor mutant library and shared it with the mycology community through the Fungal Genetics Stock Center. “I don’t want to be the gatekeeper to what people do with these mutants,” he says. In his own lab, he has used them for studies. C. albicans Host interactions such as adhesion and biofilm formation.
In 2018, Mitchell’s lab identified the effects of stress variation on biofilms. In this study, the team mutated four biofilm transcription factor genes in five clinical isolates. They found that the mutations had different effects in different strains. “We are among the first groups to try to exploit strain variations. [for] Genotype-phenotype studies are used to learn something that you couldn’t learn from just the reference strain,” he says.
Strengthening the application of genetics in mycology
In addition to gaining interest in C. albicans While directing Cold Spring Harbor’s yeast genetics course, Mitchell gained experience and made connections that were critical to co-founding the molecular mycology course at the Marine Biological Laboratory in 1997. This course was designed to explore advanced experimental techniques in pathogenic fungi, to collaborate among my next generation of entomologists.
It was here that Mitchell met longtime colleague David Andes, a physician scientist at the University of Wisconsin. Andes was a student in the course in 2002, and the labs began collaborating on research soon after. Over the past 20 years, the pair has published a combined 21 papers on the regulation of biofilm-related genes, the formation of the extracellular matrix that holds biofilm cells together, and the differences between regulatory networks. C. albicans Stress Andes noted the lasting impact the course had on him and the field in general: “Aaron continued to foster people’s careers, focus his research, and mentor people to help develop the field.”
Mitchell directed the course until 2010 and has seen its tremendous impact on the mycology community over the years. “If you look at the first class, many of these graduates are now leaders in the field of medical mycology,” says Mitchell.
Commitment to mentoring
This same commitment to developing people and promoting ideas has also defined his leadership style. One of his trainees was Sarana Fanning, now an assistant professor of neurology at Harvard Medical School and Brigham and Women’s Hospital. Fanning became part of Mitchell’s lab as a research technician and continued to work with Mitchell as a graduate student and postdoc. “Aaron’s way of teaching genetics was just so inspiring that I really wanted it to be part of my training,” she says. “He’s very invested as a teacher, whether it’s in the classroom or in the lab. He’s an extraordinarily invested mentor.” She recalls how he would always go to the lab bench and help solve the experiments. “It seems like he’s worked out how to give you that perfect balance of freedom and encouragement with room to grow, but also feeling very supported,” she says.
From trainees to longtime colleagues, Mitchell’s influence runs deep. “He’s certainly a brilliant scientist and his contributions have advanced the field, but I think [he’s] An equally important leader, not just for individuals, but for the field as well,” says Andes.
Join us in congratulating Aaron Mitchell on receiving the George W. Biddle Award for his service to the field of molecular mycology, including the creation and dissemination of new genetic tools in the community and shaping the next generation of mycologists.
