Many bacteria are exposed to a variety of environments during their lifecycles. Signals in these environments may activate expression of genes that result in changes that allow the bacterium to cope more effectively with the specific environment. One of the current aims of research in the R-J lab is to understand how bacteria survive in many distinct environments, including identifying and characterizing genes that are expressed in each environment.
From 2002-2013, the model system that the R-J lab initially used use to address these problems was the facultative intracellular bacterium Shigella flexneri, which encounters many different environments during its journey through the external environment and human host. More information can be found here about this work.
Beginning in 2006, The R-J lab began working with a second intracellular bacterium that lives inside eukaryotic cells. This bacterium, Sodalis glossinidius, is a facultative intracellular bacterium that is a secondary symbiont of the tsetse fly. The Sodalis genome has recently been sequenced, and the bacterium is phylogenetically related to E. coli. We have used this bacterium as a model organism to address the question “What are the physiological requirement for intracellular life, regardless of type of endosymbiosis?”. Recent work has focused on the role and regulation of heme, iron, and blood tolerance mechanisms of Sodalis. Additionally, we also aim to understand how Sodalis utilizes sugars, including the chitin-derived N-acetylglucosamine.
Beginning in 2023: The R-J lab is diving head first into microbes that are important in food microbiology, particularly fermentation and cheese production. Dr. R-J spent part of her sabbatical in the Fall of 2023 learning about cheese production and chesse microbiology at Jasper Hill Farms and Cellars and the R-J lab is now characterizing some of the microbes from there. Stay tuned for more information on this new area.
Work in the R-J lab has been supported by the National Institutes of Health, the Thomas F. Jeffress and Kate Miller Jeffress Memorial Trust, and the University of Richmond School of Arts and Science.