"Teaching found me”: Reflecting on over 40 years of teaching, mentorship and research with virologist Martha Brown  

Known best for spearheading multiple upper year undergraduate courses in microbiology, Martha Brown has been a professor of virology at the University of Toronto for over 40 years. As she approaches the end of her tenure, she reflected on her impact as a teacher to budding microbiologists, in the classroom and in the lab, and on the work of her research group to understand how a common group of viruses called adenoviruses infect the human gut.  

In a cozy office surrounded by stacks of microbiology textbooks, folders of annotated research articles and notebooks from previous students, Brown begins to unravel her career as a microbiologist and professor.  

As an associate professor in the department of molecular genetics at the Temerty Faculty of Medicine, Brown has been teaching at U of T since 1982. 

Over the years, she has been a key contributor to the microbiology curriculum by teaching 11 different undergraduate microbiology courses, including three upper-year courses that she helped develop. Brown also taught trainees in her graduate-level virology course, which delves into hot-off-the-press research articles reshaping how we think about viral replication. 

Brown says her teaching philosophy is to lead students on a journey of discovery. On top of her courses, Brown kept busy over the years as the academic lead for the microbiology module of the Medicine Youth Summer Program (MedYSP) where she introduced high school students to the basics of microbiology and how scientists study microbes. She served in this role for 12 years from 2008 to 2019.  

An enriching microbiology program to benefit students 

Brown joined U of T as a full-time faculty member in what was then the department of microbiology and parasitology after being a postdoctoral researcher at The Hospital for Sick Children. She had already been teaching casually at the university for two years, having been asked to teach a few microbiology classes because of her expertise with different viruses and newer techniques to study them. 

As undergraduate coordinator of the microbiology program, Brown revamped the microbiology curriculum. She had a vision of what students needed and made it a reality. 

As the university’s teaching landscape and the microbiology field have changed over the decades, Brown’s courses have evolved and endured.  

She says she gravitated toward teaching because of the instantaneous connection she feels when delivering a lecture or helping a student learn a new experimental technique.   

Even after all these years, when a student in her lab finally completes a challenging experiment and excitedly shares their results, she finds herself grinning alongside them. 

As of today, she estimates a whopping 3000 students have taken her lecture-based virology courses, with 1000 students also taking her lab courses. In 2014, she was awarded the Faculty of Medicine Excellence in Undergraduate Life Sciences Laboratory Teaching Award. It was in recognition of her prolific contribution to hands-on education in virology and her dedication to keeping the curriculum current throughout the years, incorporating experiments that make use of viral vectors, new microscopy and molecular biology techniques. 

“Dr. Brown’s mentorship gave me the confidence to think critically and build a passion for antiviral research,” says Linda Jeong, who was an undergraduate researcher in the Brown lab and is now pursuing her Master of Science degree at U of T. “Through countless one-on-one discussions analyzing data, troubleshooting experiments and planning future experiments, she showed an unwavering commitment to her students’ growth and success.” 

Despite the accolades, Brown, who is also cross appointed to the department of laboratory medicine and pathobiology, is modest and often surprised to hear she has had such an impression on her students.  

“I was not seeking teaching,” says Brown. “It found me.” 

“When you find one answer, you generate ten more questions” 

After reading a book on great medical discoveries and learning about the pivotal work of U of T’s own Frederick Banting in the discovery of insulin, Brown knew, as a 10-year-old, that she would study science. “He was my hero,” she says. 

Despite her early interest, Brown says she never intended to go to graduate school.  

Rather, she planned on being a diagnostic laboratory technician in a hospital after finishing her undergraduate studies. When she told mentors about this plan, she repeatedly met the same sentiment — “You will get bored.” They seemed to know her curious mind could only be satisfied with research, and when she found herself studying mosquitoes the summer between first and second year, she knew she had been bitten by the proverbial bug.  

As a PhD student, she studied a family of viruses that infect insects but for her postdoctoral work, she was eager to move on to viruses that affect humans. That interest led her to SickKids, where Brown’s postdoctoral research focused on a family of human adenoviruses that infect the gut and are a leading cause of diarrhea in young children.  

Brown says the main focus of her research was to understand why other adenoviruses cause diseases in multiple tissues, but these viruses only cause disease in the gut, where they can produce up to one hundred billion viral particles per gram of feces. 

Four decades on, Brown is still fascinated by this question. When she isn’t in the classroom, she and an army of students have been chipping away at this topic in the lab, observing how adenoviruses infect many different cell types and what environmental conditions allow these diarrhea-causing adenoviruses to replicate efficiently.  

Since starting her research group, 98 undergraduate students have gained some of their first research experiences in her lab, and she has supervised 12 students through their graduate studies.

Identifying the conditions and cellular pathways that these adenoviruses use to exploit to gain entry and replicate specifically in cells lining the gut would help researchers understand how these viruses cause disease. There is also a growing interest in using as oral vaccine vectors. Oral vaccines are typically cheaper and more stable than protein subunit and mRNA vaccines, making them ideal for vaccination in lower income countries.  

In one paper studying how enteric adenovirus type 41 (HAdV-41) enter cells, Brown and MSc student Tom Leung showed that up to 80% of virus particles remain on the surface of lab-grown human cells. Where other adenoviruses used proteins at the cell surface to infect, HAdV-41 seemed to hang around pockets at the cell membrane, unable to enter the cells without some other mediator.

In a 2021 paper published in Science Advances, Brown collaborated with Carmen San Martín, an investigator at the National Centre for Biotechnology in Spain. Researchers used cryo-electron microscopy to discover significant structural differences between human adenoviruses that primarily infect the respiratory tract and those that infect the small intestine. They identified several differences that may enhance stability of the gut-infecting viruses and allow them to be activated by the acidic environment as they travel through the stomach to target cells in the intestine.   

With her teaching days behind her, Brown plans to take the next year or two to wrap up the research projects in her lab. She will continue to mentor undergraduate students and further explore how the unique environmental conditions of the gastrointestinal tract — such as low pH or metabolites made by gut bacteria — might open cellular doors for these viruses.  

“I have been blessed to teach what I wanted to teach.” 

For trainees who are considering entering teaching-stream faculty positions, Brown strongly recommends still finding time to do lab work. She says insights from doing research can greatly enhance a person’s ability to critically engage with research-based course material.   

“When an experiment did not go as planned, she calmly helped me retrace my steps, troubleshoot the issue, and view the mistake as a valuable learning opportunity rather than a setback,” says Maryam Ferouz, who completed her fourth-year thesis project with Brown, and is now completing her master’s in biotechnology at York University. “Her encouragement, understanding, and genuine recognition of my growth gave me the confidence to improve and develop as a researcher.” 

While she may not have planned to have such an extensive teaching career, Brown says she has found satisfaction in seeing students benefit from her courses and mentorship. Thanks to Brown’s leadership, countless young scientists have embarked on a journey of discovery — whether that was for a semester or their entire career — and these courses will continue to grow and adapt with new breakthroughs in microbiology. 

Her legacy will be the thousands of students who have come away from her courses feeling more confident in their lab skills and having learned something new about the microscopic life that cohabits our world.  

“Teaching is a commitment,” she says. “I did it for the students.” 

This article was originally published by EPIC and has been adapted for the Department of Molecular Genetics.