Meeting Abstract

P2.159  Sunday, Jan. 5 15:30  Developing Proxies for Evaluating Cross-Protection in Channel Catfish Ictalurus punctatus TAYLOR, G.R.; GREEN, C.C; KUHL, A; HAUKENES, A.H.*; University of Arkansas at Pine Bluff; Louisiana State University; Louisiana State University; University of Arkansas at Pine Bluff ahaukenes@uaex.edu

Molecular chaperones and their involvement with induced cross-protection (CP) are important components of an organismal response to environmental stress. Increasingly, molecular chaperones, such as HSP70, and CP are being examined in a therapeutic context in both human and veterinary medicine. For example, we have previously observed that brief bouts of heat treatment of channel catfish lead to both an enhanced resistance to subsequent heat extremes and an increased tolerance to noxious changes to water chemistry. We are currently evaluating cellular markers for this organismal response in order to more efficiently evaluate protocols designed to induce CP in finfish. In recent experiments we measured HSP70 mRNA expression in gills of channel catfish following treatments previously observed to induce CP. A time-series experiment comparing non-treated channel catfish to fish that were briefly exposed to 36°C was performed. Both these groups were then compared to channel catfish that were exposed to 36°C for one hour. Relative rates of expression of HSP70 mRNA in gills from channel catfish briefly exposed to 36°C was significantly higher than control animals immediately after treatment. However, no differences between these two groups were observed at 30 and 60 minutes after treatment. Gills from both of these groups had significantly lower HSP70 mRNA expression than catfish held at 36°C for one hour. While it is not surprising that the increased duration of heat treatment led to a more robust signal of HSP70 activation, the marginal increase (relative to non-treated control animals) in the expression of HSP70 mRNA in fish that were administered a heat treatment that was known to induce CP warrants further examination.