PROSSEB 



on muscle where both glucose and succinate were used as sub- 

 strates. Her values for cold- acclimated fish seemed not to change 

 at all. They stayed high, so that after some weeks the value in the 

 cold was higher than the warm, hence the acclimation response 

 was reduced activity in the warm acclimated animals with virtually 

 no change in the cold acclimated animals. All the enzyme data that 

 I gave you were from fish that had been on a 12 hour photoperiod. 



HANNON: A number of things are variables here that we know 

 very little about. And one of them is the variable of intermittent 

 exposure. Other factors are the effects of changes in light as well 

 as changes in the age or changes in the size of the animal. All of 

 these variables, at least potentially, could lead to a big difference 

 in the type of response you get. 



HART: I would like to ask one other thing in connection with 

 the enzyme work; since there appear to be large changes asso- 

 ciated with the overall activity of the animal during acclimation, 

 I wonder if enzymes associated with the maximum metabolism might 

 be worth investigating. 



PROSSER: How are you going to find these? 



HART: I wonder if the cytochrome oxidase activity would have 

 some bearing on this. 



JANSKY: We could expect some differences in the cytochrome- 

 oxidase activity and especially in the shifting of the optimum of 

 this enzyme according to the temperature of acclimation. We have 

 some evidence about it on insects. 



HART: What would be your opinion of this approach, Dr. 

 Jansky? 



JANSKY: I would say we could find some differences in the 

 maximum metabolism, and especially in the shifting of the tem- 

 perature for maximal enzyme activity. 



42 



