Matthew Waldor studies the evolution, cell biology, and pathogenicity of enteric bacteria that cause human disease.
Cell Biology and Virulence of Enteric Pathogens
We investigate fundamental and translational questions related to human enteric pathogens, including Vibrio cholerae, Vibrio parahaemolyticus, and enterohemorrhagic Escherichia coli (EHEC). Our ongoing projects include the following:
I. Vibrio cholerae chromosome segregation and replication. Using a combination of genetic and biochemical approaches, along with fluorescence microscopy, we are exploring the mechanisms that mediate the segregation and replication of the two chromosomes. Homologs of plasmid partitioning (par) genes found on each chromosome appear to mediate the segregation of the two chromosomes in a specific manner. We are defining how these sets of Par proteins mediate V. cholerae chromosome segregation.
II. sRNA control of virulence. Small untranslated RNAs (sRNAs) regulate many cellular processes in nonpathogenic E. coli. Hfq is an RNA-binding protein that is important for the activity of many sRNAs. We found that V. cholerae and EHEC lacking Hfq are attenuated in virulence, suggesting that sRNAs, in conjunction with Hfq, control processes that are critical for their pathogenicity. We developed a computer program that enables the rapid identification of putative sRNAs in intergenic regions of bacterial genomes. We are using this software to investigate the targets and mechanisms of action of several of the sRNAs that were identified, and we are developing deep sequencing approaches to globally characterize bacterial transcriptomes, including sRNAs.
III. Use of infant rabbit models of diarrheal disease to study host-pathogen interactions. Studies of the biology of enteric pathogens during infection have been hampered by the lack of nonsurgical small animal models of diarrheal disease. We found that infant rabbits orally inoculated with EHEC or V. cholerae develop severe diarrheal diseases that mimic human infections. We are taking advantage of these models to gain insights into bacterial physiology during growth in the host as well as host-pathogen interactions.