Date of Award


Degree Name

MS in Biological Sciences


Biological Sciences


Pat Fidopiastis


Vibrio salmonicida causes cold-water vibriosis in salmon populations around the world and causes financial damage to fisheries designed to farm these salmon. Very little is known about the physiology of how V. salmonicida causes disease and measures to contain vibriosis are restricted to either vaccinating individual fish against disease or administering antibiotics when an outbreak is detected. These procedures are costly and increase the risk for selection of antibiotic-resistant V. salmonicida strains. A recent reoccurrence of outbreaks in Norwegian fisheries provided incentive to better understand the virulence mechanisms of V. salmonicida. In this thesis, a proteomic approach was used to identify proteins that were differentially expressed when cells were grown in vitro under simulated virulence conditions (i.e. 5˚C and in the presence of exogenously supplied autoinducer 3-oxo-hexanoyl-homoserine lactone). Some examples of proteins with significantly altered expression that stood out at as homologs of potential virulence factors were: an exported serine protease DegQ, a multi-drug transporter HlyD, and an outer membrane protein OmpU. The proteomic approach allowed us to identify large numbers of proteins that are expressed by V. salmonicida, facilitating hypothesis-driven research in order to support possible roles for some of these proteins in virulence