by Madelyn Ostendorf
Lucille Jonas did not set out to become a microbiologist. In fact, she arrived at Iowa State University with a very different goal in mind: to become a veterinarian. A general microbiology course in her first year shifted that trajectory and set her on a path toward graduate research examining a little-understood aspect of animal biology.
“I found that I really enjoyed doing microbiology wet lab work, and the research process in general was really interesting and fun to me,” Jonas said. “I decided to stay for grad school and keep learning and discovering.”
Now a fourth-year doctoral candidate under the mentorship of Dawn Koltes and Stephan Schmitz-Esser, Jonas is working on research centered on an understudied frontier: the reproductive tract microbiota of livestock animal species, including cattle, pigs and sheep.
Jonas took ANS 3310: Domestic Animal Reproduction in her junior year and was fascinated by the complexity of the animal reproductive system.
“It's a wonder that any of us are here, because so many things can go wrong during the reproductive process,” Jonas said. “It's a wonder that we even have more cattle and more sheep, because when you look at it, the rate of conception can be as low as 50% depending on the farm. I think the challenge of the reproductive process is what made it really interesting.”
The project grew from a comparison to the human reproductive tract, where lactic acid bacteria dominate and help maintain a stable environment. In livestock, the picture is far more complex.
“In livestock, instead of having one group of bacteria dominating the environment, we are seeing a lot of richness and evenness in the microbes that are there. The challenge is a lot of them are historically considered pathogenic, or harmful, in literature,” Jonas said.
With that in mind, she set out to explore the role these “harmful” bacteria play in a reproductive tract that has been evaluated as healthy.
Using existing data, she and her team worked to identify core bacterial populations that consistently appear in healthy animals. That effort helped narrow the focus of her subsequent projects to specific bacterial groups of interest.
Among those groups is the Pasteurellaceae family, which includes several respiratory pathogens. Jonas found members of this family frequently present in the healthy vaginal microbiota of cattle, pigs and sheep. Until recently, most records of their presence came from culture-independent techniques that identify microbes through their DNA rather than by growing them in the lab.
To better understand their function, Jonas worked to isolate these bacteria and move them into a controlled lab setting.
Jonas then conducted a whole-genome sequencing project involving 27 isolates. The goal was to move beyond identifying which bacteria are present and begin uncovering what traits they carry.
“From there we were basically hunting in their genomes to find traits that might be interesting to study further,” she said.
The genomic work set up her next phase of research, which uses cell culture to examine how specific bacteria interact with mammalian cells.
One species of interest is Histophilus somni. Known as a major contributor to bovine respiratory disease, it is also highly prevalent in the vaginal microbiota of dairy cattle and sheep. Jonas is studying how it interacts with mammalian cells to determine whether it harms or coexists with host tissue.
The findings could help clarify a larger question that runs through her work: whether bacteria traditionally considered pathogenic might play a beneficial role in a healthy reproductive environment.
Jonas' work is anchored in Iowa State’s livestock facilities, which provide the samples she studies. Using those resources, she has been able to examine microbes from cattle, pigs and sheep raised on campus, connecting her lab work to real-world systems.
Jonas hopes her research can help farmers better understand whether the reproductive tract microbiota can be manipulated to improve livestock fertility. For now, she continues to examine bacterial genomes and their interactions with host cells in vitro, building a clearer picture of a system that remains largely unexplored.