Mechanisms of Escherichia coli and Vibrio cholerae fitness when grown in co-culture




Longoria, Candace

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Vibrio cholerae is a gram negative bacillus that possesses a single flagellum and is commonly known to have two toxigenic strains: serogroups O1 and O139; both are causes of epidemics. V. cholerae normally lives in brackish aquatic environments that have varying conditions that include temperature, salinity, and pH. Escherichia coli is normally found in the intestinal tract and E. coli K-12 is a commensal non-virulent strain used in many laboratory settings. E. coli and V. cholerae were observed in planktonic and biofilm mixed cultures and V. cholerae was seen to have a reduced fitness in the biofilm environment. To test which E. coli genes are essential for growth with V. cholerae, we used the E. coli KEIO knockout collection of specific K-12 genes and tested the ability of various knockouts to grow with V. cholerae. Once the initial screening was complete we saw the deletion of peptidase activity, most so with pepA-, had visible changes in fitness and growth in both planktonic and biofilm mixed culture. We also used various pepA strains and plasmids with altered DNA-binding and peptidase activity and observed the growth in mixed culture over a forty-right hour period. Based on our data, biofilm mixed culture and the lack of peptidase activity may affect the growth and fitness of both E. coli and V. cholerae.



Escherichia coli, Vibrio cholerae, Mixed culture, Co-culture, Biofilm, Competition, Fitness


Longoria, C. (2016). <i>Mechanisms of Escherichia coli and Vibrio cholerae fitness when grown in co-culture</i> (Unpublished thesis). Texas State University, San Marcos, Texas.


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