Submitted to: Aquaculture America Conference
Publication Type: Abstract Only
Publication Acceptance Date: 9/30/2002
Publication Date: 2/18/2003
Citation: HUELS, K.L., DELANEY, M.A., BRADY, Y.J., AN, H. PROTEIN PROFILE CHANGES IN VIBRIO VULNIFICUS ISOLATED FROM THE EASTERN OYSTER CRASSOSTREA VIRGINICA (GMELIN)FOLLOWING A TEMPERATURE DOWNSHIFT. AQUACULTURE AMERICA CONFERENCE. 2003. Interpretive Summary:
Technical Abstract: Vibrio vulnificus is primarily transmitted by raw or improperly prepared molluscan shellfish and can cause gastroenteritis, primary septicemia and in severe cases result in death. The persistence of V. vulnificus in the Gulf of Mexico during the summer months restricts the harvesting of the Eastern oysters, Crassostrea virginica (Gmelin), from these areas due to the human health hazard posed by V. vulnificus. Despite the elevated V. vulnificus bacterial counts in the oyster and water, during periods of elevated water temperatures, V. vulnificus is nearly undetectable using conventional plate count methods as water temperatures decrease. Numerous studies indicate a link between temperature and viability of V. vulnificus. Since temperature manipulation is a major form of food preservation, immediate chilling has been suggested to prevent the outgrowth of potential human pathogens such as V. vulnificus. However, if a cold shock response that increases cell viability and reproduction at sub-optimal temperatures is implicated by V. vulnificus immediate chilling of C. virginica would negate the initial intent of reducing total V. vulnificus colony forming units (CFUs) when the product reached the consumer. The intent of this project focused on protein changes of V. vulnificus in response to a downshift from ambient internal oyster temperature to 13oC and 4oC. Vibrio vulnificus was isolated from C. virginica using a DNA probe. The V. vulnificus cultures were grown out, then cold shocked. Protein profiles were observed using one and two dimensional gel electrophoresis. Despite the absence of an observable classical cold shock protein, variability was observed between ambient temperature, 13o C and 4o C. In addition to changing profiles, as hypothesized, there was increased variability in cells incubated at 13 o C. Also, expression of varying proteins in both cold shocked samples was transient, typical of stress responses. This preliminary work needs to be followed up on, and expanded to further understand how V. vulnificus responds to cold temperatures. By increasing understanding of this, the general management practices of C. virginica collection and post harvest handling need to be altered accordingly to maintain a relative level of food safety.