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Melanie Hurst

Department: Microbe-Host Interaction

Faculty Mentor: Maria Hadjifrangiskou, Ph.D.

Dissertation DescriptionCross-interaction Between Signal Transduction Systems that Mediate Virulence in Uropathogenic Bacteria

In the Hadjifrangiskou lab, we study regulatory systems that mediate behavior, metabolism and virulence within uropathogenic Escherichia coli (UPEC), the leading cause of urinary tract infections. I am particularly interested in signal transduction pathways that mediate virulence. Bacteria exist in diverse environmental niches. To do this, they must be able to rapidly respond and adapt to their surroundings. Two-component signal transduction systems (TCSs) allow for signal detection and appropriate bacterial response. TCSs typically contain a sensor histidine kinase and a response regulator that typically act as a receptor and transcription factor respectively.

Previous work in the Hadjifrangiskou lab has demonstrated cross-interaction between the QseBC and PmrAB TCSs. In the presence of ferric iron, this relationship confers polymyxin B resistance. The ultimate goal of my project is to characterize the interface of cross-interaction between these two TCS that mediate virulence in UPEC and determine the molecular mechanisms which drive PmrAB and QseBC. Through these studies we aim to identify methods  to break the connection.