Gina Lewin - June 2021

Gina Lewin is a postdoctoral fellow in Marvin Whiteley’s lab in the School of Biological Sciences and the Center for Microbial Dynamics and Infection at Georgia Tech. She is passionate about studying how interactions between organisms influence their behavior and their evolution. Since starting her postdoc in 2016, Gina has used her background in microbial ecology and evolution to study microbe-microbe interactions in the oral cavity. In our mouths, microbes live in complex communities on the surface of teeth (plaque). These microbes are important for human health; not only do oral microbes cause two of the most prevalent diseases, cavities and gum disease, but they also have regular access to the bloodstream where they are implicated in diseases such as endocarditis and cancer. Scientists, including researchers in the Whiteley lab, have shown that microbes in the oral cavity form complex interactions, and importantly, these interactions influence disease. Specifically, Gina studies how interspecies interactions influence the behavior and virulence of the periodontal pathogen Aggregatibacter actinomycetemcomitans (Aa). In her research, Gina asked: how similar are interactions among microbes in the oral cavity, and beyond? If a microbe interacts a certain way with species A, will it also interact the same way with species B? Further, this project included both oral and non-oral microbes to ask how interactions differ between microbes that are native to the same environment and those that are not. To answer these questions, Gina performed large-scale transposon sequencing analyses to determine the genes that Aa needs to grow (its essential genome) in the presence of 25 other microbes. This work showed that Aa’s essential genome changes drastically depending on the interacting partner. Notably, Aa survived better with non-oral microbes and, in some cases, non-oral microbes considerably alleviated essential gene requirements. Gina was awarded an F32 postdoctoral fellowship through the National Institutes of Health for this postdoctoral work. Gina grew up in Hopewell, New Jersey. As an undergraduate at Pomona College in California, she discovered her interest in research while studying isopod evolution and the microbial ecology of mud volcanoes. She received a BA in molecular biology from Pomona in 2010 and then joined Cameron Currie’s lab as part of the Microbiology Doctoral Training Program at University of Wisconsin-Madison. Using research approaches ranging from field work to experimental evolution to bioinformatics, Gina contributed to our understanding of how microbes and microbial communities degrade plant biomass in association with insects. Specifically, she showed how insect-associated Streptomyces have evolved to be highly cellulolytic. In addition, she studied cellulose degrading microbes from the refuse dumps of leaf-cutter ants, uncovering dynamics of competition in these communities during experimental enrichment. She also helped adapt this research to teach about symbiosis, carbon cycling, and biofuels in college and high school classes and at science festivals. When she is not doing science, Gina loves being outside, exploring new cities, and spending time with friends. Find her on twitter @Gina_Lewin