The objective of my laboratory is to characterize how molecular communication between bacteria and their animal hosts leads to specific and reproducible colonization. To accomplish this goal, the laboratory studies the V. fischeri-squid system. This system is advantageous because bacteria colonize through the natural route of infection, all animals are colonized within three hours of inoculation into the seawater, the bacteria can be subject to detailed genetic manipulation, and the precise site of infection can be imaged directly in the live animal host, allowing for cutting edge genetic and genomic approaches. Focusing on how squid are reproducibly colonized by the specific symbiont, to the exclusion of the millions of competing bacteria in seawater, has revealed key roles for bacterial aggregation and biofilm formation in promoting specific host- microbe interactions. Recently our global genetic screen to identify colonization factors revealed multiple novel biofilm activators and identified an orphan histidine kinase, which acts as a negative regulator of Syp biofilm development in vivo. To elucidate the pathways governing colonization and biofilm development in the animal host we will (1) dissect the molecular details of the novel histidine kinase pathway, (2) define at high temporal and spatial resolution the steps necessary for the establishment of this mutualistic relationship, and (3) characterize the role of new colonization factors using genetic and metabolomic approaches. Since the strategies used by V. fischeri to interact with its host are conserved in other host

Public Health Relevance

PARENT AWARD R35GM119627 NARRATIVE Bacteria that colonize animals transition from an environmental lifestyle to the host-associated state, in which individual bacterial cells coordinate functions to act as a group. Using a model system that allows for interrogation of bacteria directly within the animal host, this project addresses how molecular signaling from the host directs the bacteria to form biofilms, matrix-encoded groups of cells that are widespread and often underlie antimicrobial resistance. Information in the model will then be used to improve beneficial bacterial colonization (e.g. probiotics) and interfere with colonization by pathogens.

National Institute of Health (NIH)
National Institute of General Medical Sciences (NIGMS)
Unknown (R35)
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Study Section
Special Emphasis Panel (ZRG1)
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Sledjeski, Darren D
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University of Wisconsin Madison
Schools of Medicine
United States
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Mandel, Mark J (2018) D-fining DarR: a LysR-type transcriptional regulator that responds to D-aspartate. J Bacteriol :
Thompson, Cecilia M; Tischler, Alice H; Tarnowski, Denise A et al. (2018) Nitric oxide inhibits biofilm formation by Vibrio fischeri via the nitric oxide sensor HnoX. Mol Microbiol :
Speare, Lauren; Cecere, Andrew G; Guckes, Kirsten R et al. (2018) Bacterial symbionts use a type VI secretion system to eliminate competitors in their natural host. Proc Natl Acad Sci U S A 115:E8528-E8537
Henry, Christopher S; Rotman, Ella; Lathem, Wyndham W et al. (2017) Generation and Validation of the iKp1289 Metabolic Model for Klebsiella pneumoniae KPPR1. J Infect Dis 215:S37-S43
Mandel, Mark J; Dunn, Anne K (2016) Impact and Influence of the Natural Vibrio-Squid Symbiosis in Understanding Bacterial-Animal Interactions. Front Microbiol 7:1982