Date of Completion

Spring 5-2-2018

Thesis Advisor(s)

Dr. Xiaohui Zhou

Honors Major



Pathogenic Microbiology


Vibrio parahaemolyticus has the capability to be acid resistant due to known and unknown mechanisms. The goal of this project was to determine possible genes involved in conferring acid resistance of this bacterium. The vp1277 gene (designated as HA) and its downstream gene vp1999 were investigated for their role in acid resistance. Another potential gene that could contribute to acid resistance is vp0820 because of its similarity to the ToxR gene in Vibrio cholera. All three of these knockout strains and the wild type were grown in neutral LB and then tested with acidic LB’s of pH 4.5, 5, and 5.5. Despite its similarities to cholera, the vp0820 knockout did not appear to lead to decreased bacterial growth when treated with acid. The HA and vp1999 knockout strains grew less when treated with acid especially at pH 4.5. Once vp1999 was identified as possibly being involved it was ligated into the pmmB207 plasmid and conjugated into sm10 E. coli to determine if this addition into the genome could be successfully completed. The vp1999 gene was determined to have been conjugated effectively by PCR and gel electrophoresis. Also, prior to this PCR amplification was run to amplify the vp1999 gene in the wild type and vp1999 knockouts. The wild type band appeared at approximately the length of the vp1999 gene and the gene was unable to be amplified in the knockout confirming the knockout and that the primers designed work. Overall, both vp1277 and vp1999 may be involved in acid resistance of V. parahaemolyticus.