Cross-tolerance in the tidepool sculpin: the role of heat shock proteins.
Cross-tolerance, or the ability of one stressor to transiently increase tolerance to a second heterologous stressor, is thought to involve the induction of heat shock proteins (Hsp). We thus investigated the boundaries of cross-tolerance in tidepool sculpins (Oligocottus maculosus) and their relationship to Hsp70 levels. Survival of sculpins exposed to severe osmotic (90 ppt, 2 h) and hypoxic (0.33 mg O(2)/L, 2 h) stressors increased from 68% to 96%, and from 47% to 76%, respectively, following a +12 degrees C heat shock. The magnitude of this heat shock was critical for protection. A +10 degrees C heat shock did not confer cross-tolerance, while a +15 degrees C heat shock was deleterious. Sculpins required between 8 and 48 h of recovery following the +12 degrees C heat shock to develop cross-tolerance. There was no association between Hsp70 levels before the onset of the secondary stressor and cross-tolerance. However, branchial Hsp70 levels following osmotic shock were highly correlated with the time frame of cross-tolerance. Thus, Hsp70 induction by the priming stressor may be less important than the ability of the cell to mount an Hsp response to subsequent stressors. The time frame of cross-tolerance is similar to the interval between low tides, suggesting the possible relevance of this response in nature.
Todgham
Anne E
AE
Faculty of Agricultural Sciences, University of British Columbia, Vancouver, Canada. todgham@interchange.ubc.ca
Schulte
Patricia M
PM
Iwama
George K
GK
D000064:Acclimatization / Q000502:physiology*; D000704:Analysis of Variance; D000818:Animals; D015153:Blotting, Western; D001955:British Columbia; D004591:Electrophoresis, Polyacrylamide Gel; D005399:Fishes / Q000235:genetics* / Q000502:physiology*; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism* / Q000502:physiology; D006358:Hot Temperature; D008099:Liver / Q000378:metabolism; D009997:Osmotic Pressure; D013997:Time Factors
D018840:HSP70 Heat-Shock Proteins