2023 signals the 101st year of microbiology at UC Davis. From the discipline’s humble beginnings as a one-person research and teaching unit in the College of Agricultural and Environmental Sciences, microbiology at Davis has grown and diversified.

“We're beginning the second century of microbiology at UC Davis, and it has taken quite a turn from its beginnings in dairy microbiology,” said Wolf-Dietrich Heyer, a Distinguished Professor and chair in the Department of Microbiology and Molecular Genetics, who has been with the department since 1998 and chair since 2012. “The innovation driven by microbial research has shaped the life sciences and our society; from the molecular biology revolution to mRNA-based vaccines in the COVID-19 pandemic,” said Heyer.

Today, microbiology has a significant presence across the Schools of Medicine and Veterinary Medicine, and the Colleges of Biological Sciences, Agricultural and Environmental Sciences, Engineering, and Letters and Science.

To celebrate its 101st year at UC Davis, we’re taking a decade-by-decade look at how microbiology has evolved during its first century on campus.

1920s: Origins in Dairy Science

Courtland Mudge became the first bacteriologist at UC Davis in 1922, working in the Department of Dairy Industry, which was located at Roadhouse Hall near the present-day site of the School of Education. Mudge’s research focused on bacterial contamination of cow’s milk.

Mudge published several articles during this decade that described the characteristics of Streptococcal bacteria in cow’s milk and udders, and explored methods to identify bacterial contamination in fresh and stored milk.

1930s: The First Course

In the 1930’s, Mudge began offering a general course in bacteriology to Davis undergraduates.

Mudge also published several articles during this decade on various aspects of dairy bacteriology, including the bovine immune response to mastitis, the impacts of agitation, chlorine, and staining on milk bacteria, and studies of the nutritional needs and physiological characteristics of Streptococci in milk.

1940s: Expanding the Faculty

The 1940’s saw the number of bacteriology faculty triple. Mudge was joined by Mortimer Starr in 1947 and Donald Reynolds in 1948. Starr was an expert in the bacterial diseases of plants, while Reynolds specialized in the bacterial degradation of chitin, the polysaccharide that makes up insect and crustacean shells.

Graduate instruction in microbiology began at Davis in 1949. Master’s and doctoral students were jointly advised by faculty who used microorganisms as experimental systems in various units, including Dairy Science, Plant Pathology, Food Science and Veterinary Medicine.

1950s: A New Department is Formed

In 1951, bacteriology was recognized with its own department within the newly established College of Letters and Science. Mudge served as the Department of Bacteriology’s first chair. At this time, the department’s main strengths were bacterial physiology and metabolic diversity.

Undergraduate teaching continued, and bacterial physiologist Allen Marr joined the department in 1952 as an instructor. Together with Mudge, Starr, and Reynolds, Marr worked to develop a multi-course curriculum for the new B.A. in bacteriology undergraduate major, which enrolled five students in 1952, the first year it was offered. The curriculum was geared towards teaching the intrinsic features of microbes rather than medical applications.

In 1956, Robert Hungate, who is known for his pioneering methods of culturing anerobic bacteria from inside termite gastrointestinal tracts and cow rumens, was hired as chair to replace the retiring Mudge.

In 1959, as part of the California Master Plan for Higher Education, the UC Berkeley “University Farm at Davis” became a general campus of the University of California and began a major reorganization and expansion of all research and teaching as UC Davis.

1960s: A Diversifying Curriculum

In 1960, the first female faculty and genetics researcher, Monica Riley, joined the department. Riley’s research focused on the physiology and genetics of E. coli bacteria, and, prior to joining Davis, she contributed significantly to the discovery of messenger RNA.

The department was also joined by three more faculty: microbial physiologist John L. Ingraham, who transferred from the Department of Viticulture and Enology and became department chair in 1962, microbial geneticist Donald Kessler, and the department’s second female faculty member, bacterial physiologist Wiltraud Pfeiffer, who studied the physiology of Mycobacterium tuberculosis.

In 1964, the department offered a B.S. in bacteriology for the first time, which involved more coursework in mathematics and physical sciences than the previously offered B.A. In the 1964-1965 academic year, eight students graduated with a B.S. in bacteriology and 120 undergraduates were enrolled across the program.

1970s: Expanding Beyond Bacteria

The Department of Bacteriology grew substantially during the 1970’s with the appointments of bacterial researchers Mark Wheelis, Sydney Kustu, Paul Baumann, Stanley W. Artz, and John Meeks. Two virologists, David Pratt and JaRue S. Manning, also joined the faculty, continuing the expansion of the department’s research beyond the study of bacteria.

Wheelis studied the physiology of antibiotic-producing Streptomyces spp. bacteria. Pratt, who received his doctoral degree at UC Davis in tomato genetics, taught virology and later served as department chair.

Baumann, Kustu and Manning arrived in 1973. Baumann studied the diverse metabolism and taxonomy of Pseudomonas species and was later honored as the species name of the bacterial pathogen Acinetobacter baumannii.

Kustu was the third female faculty member in the department. She received her Ph.D. in Biochemistry at UC Davis and studied transcriptional control of nitrogen metabolism in bacteria. Artz, who taught at both undergraduate and graduate levels, studied the control of gene expression in bacteria.

1980s: The Field Continues to Grow

The early 1980’s saw an explosion in the field of molecular biology, leading to gene cloning, generation of transgenic organisms, and the formation of biotechnology startup companies.

More faculty were added to the department, too. Plant pathologist William Timberlake, who studied the fungus Aspergillus, virologist Martin Privalsky, who studied nuclear hormone receptors in normal and cancerous cells, and microbial ecologist Douglas Nelson, who studied the physiology of autotrophic sulfur oxidizing bacteria, all joined the department.

 “A change came when we hired William Timberlake,” said Professor Emeritus John Meeks. “That move really took the department out of bacteriology and got us into eukaryotes.”

In 1988 the department was renamed the Department of Microbiology to reflect the diversification of its research to include other, non-bacterial microorganisms, such as viruses, fungi, and protozoa. 

1990s: A Focus on Genetics and Biochemistry

Departmental research became increasingly focused on genetics and biochemistry during the 90’s. Eight faculty joined in this decade: microbial geneticists and biochemists Michele Igo, Stephen Kowalczykowski, Mitchell Singer, and Valley Stewart; microbial physiologist Merna Villarejo; yeast cell biologist Daniel Klionsky, yeast geneticists Kazuhiro Shiozaki and Wolf-Dietrich Heyer.

“There was another transition when we hired Steve Kowalczykowski, who works on DNA recombination,” said Meeks. “At one point he had one of the most viewed science videos in the world: beautiful single molecule experiments that visualized a protein binding to and unwinding double stranded DNA.”

2000s: A New Millennium of Study

The Department of Microbiology continued to welcome faculty during the new millennium, many of whom brought with them new research methods and fields of study.

New faculty included Rebecca Parales, who studies microbial degradation of environmental pollutants, Lorena Navarro, who studied bacterial virulence factors and host defense, microbial geneticist John Roth, Giardia biologist Scott Dawson, geneticist Neil Hunter, and Su-Ju Lin and Lifeng Xu, who explore different molecular aspects of aging.

Food Science professor emeritus Chester Price transferred to the department along with his longstanding research on the stress response in Bacillus.

2010s: Renaming and Redefining

In 2013, the Department of Microbiology was renamed the Department of Microbiology and Molecular Genetics to recognize the scope of its research and instruction, and in particular the increasing focus on genetics—sometimes in the absence of microbes.

“The name also acknowledges that the origin of molecular genetics was with microbes,” said Heyer. “It's not an artificial joining of two names, it's really a historically and logically linked combination of two fields.”

This decade also saw a notable increase in interdisciplinary work within the department. Microbiologist and systems biologist Michael Savageau transferred part of his appointment from the College of Engineering to the department, bringing new expertise in quantitative modeling. Mathematician Mariel Vazquez, the first jointly appointed faculty between the College of Letters and Science and the College of Biological Sciences, joined in 2014. Priya Shah, the first joint hire between the College of Engineering and the College of Biological Sciences, joined in 2016.

“Each of these people are the incarnation of interdisciplinary research,” said Heyer.

Additional new faculty included Katherine Ralston, who studies host-pathogen interactions in parasitic Amoeba; immunologists Sean Collins and Jacqueline Barlow; virologist Samuel Diàz Muñoz; and cancer epigeneticist Chang-il Hwang, who was jointly hired with the UC Davis Comprehensive Cancer Center.

In 2014 the department launched a scientific literacy course for non-majors as a “way for students to understand more about the biology they encounter in their everyday lives,” said Scott Dawson, who helped create the course together with Jodi Nunnari from the department of Molecular and Cellular Biology, which also covers important topics in microbiology, like the human microbiome, viruses, and antibiotic resistance. “I think this is the microbiology the average citizen should understand, and of course in 2020 the importance of scientific literacy became strikingly obvious.”

With a growing student population, the department brought Miriam Markum on board as its first Professor of Teaching to implement learner-centered teaching practices and provide engaging learning experiences for students.

2020s: New Concepts, New Advances

The 2020’s have only just begun, but the department has been working hard to modernize its curriculum, starting by renaming the major in 2021—from “Microbiology” to “Molecular and Medical Microbiology”—to better reflect the major’s broad focus.

“I think it's important to acknowledge change by changing names, because we cannot deliver new concepts in old clothes,” said Heyer.

The department has also taken great pains to introduce new content, make laboratory courses available at more times throughout the year, and modernize teaching methods with the help of two newly hired teaching faculty, Kenjiro Quides and Jonathan Bragg. These changes have already been fruitful, as more and more UC Davis students choose to major in Molecular and Medical Microbiology.

“It's really voting by your feet when the overall student numbers remain consistent and our major is going up exponentially,” said Heyer.

The faculty were also recently joined by reproductive and stem cell biologist Satoshi Namekawa, who has bolstered the department’s already strong chromosome biology research program.

Looking to the Future

The Department of Microbiology and Molecular Genetics is looking forward to—and ready for—the second century of microbiology at UC Davis.

“In terms of academic research, we have defined areas of excellence that we want to maintain and grow, such as genome stability, microbial physiology, host-pathogen interactions, and basic immunology,” said Heyer. “We have no shortage of ideas about how to modernize our major and our teaching so that they reflect the research of our faculty. That's always the hope at a university like UC Davis: that you can translate cutting-edge research into cutting-edge teaching.”