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Senior Biology major Holly Nichols has been busy at Tech – she’s earned a 4.0 GPA, ventured across the equator for GT’s Pacific Study Abroad Program, spent free time caving, and worked for 3 years as an undergraduate researcher. As a sophomore Holly took Microbiology and then as junior Molecular Microbiology, where she was immersed in experimental design and bacterial genetics, and learned that serendipitous discoveries often occur because “chance favors the prepared mind”, a quotation from pioneering microbiologist Louis Pasteur. In 2016, Holly joined the lab of Dr. Brian Hammer, a Biological Sciences faculty member in the CMDI. Over the next several years Holly launched several projects studying the waterborne pathogen Vibrio cholerae. Like others in the lab Holly studies a toxic harpoon called a Type 6 Secretion System (T6SS), which V. cholerae and many other microbes wield to kill competitors.
Standard protocols with nutrient-rich medium have reproducibly documented ignominious defeat of timid E. coli in lab death matches against T6 V. cholerae killers. But in January 2018 Holly initiated a slightly modified experiment using minimal medium that required the selection of certain ingredients. To her surprise, Holly observed that the mighty V. cholerae appeared unable to kill the E. coli underdog when a particular component was added to the minimal medium. Holly recounts “I assumed I had made a mistake”. But that same ingredient also had the same effect when added to rich medium. After countless replicates and protocol modifications, Holly discovered that indeed addition of one particular ingredient endows E. coli with the ability to withstand attacks by V. cholerae killers. Holly’s collaborator, Gabi Steinbach, in Dr. Peter Yunker’s physics lab, agrees. Using fluorescence microscopy, Gabi sees that E. coli grown with this additive are largely immune to the wrath of cholera and happy replicate along with their competitor, taking up space and resources. The question remaining is – How is E. coli doing this? Days before commencement, Holly and her graduate mentor Cristian Crisan were busily testing a hypothesis that in response to this additive E. coli can alter its outer surface coat to defend itself, like other microbes that beef up their armor to protect against viral infection or the host immune system. Right now at the early stages of this project, Holly and Dr. Hammer are not revealing the nature of that additive. Perhaps Holly’s surprising result has uncovered that for unassuming E. coli and maybe other bacteria, the best offense is a good defense.
Where is this intelligent and adventurous Jacket off to next? Holly will be exploring lava tubes in Hawaii this summer before beginning a lab technician position at the University of Tennessee. In fall 2020, Holly will embark on a PhD program in microbiology at the University of Wisconsin-Madison. As CMDI co-director Frank Stewart noted after seeing Holly’s thesis presentation “Her work is everything we should be striving for in our students. Logical/thorough experimental design, exciting results, and clear next-step questions.” Knoxville and Madison are in for a treat.