240 Discussion 



Mollison: Yes, but it does seem to have a sufficiently complex meta- 

 bolism; it may be better to start and understand it and then go on to 

 a more complicated cell. 



Rowlands: I suppose the other possibility would be to use avian blood 

 cells. 



Mollison : Yes. Of course, some work has been done with it. 



Montagna: On the contrary, might not that be considered an advan- 

 tage as far as the red cell is concerned, because it can only go in one 

 direction, that is death. And since you are getting the cell at the very 

 last phase of its life, it might be a very advantageous thing to know 

 what these processes which lead up to death might be. 



Parkes: Would you not say that any cell which changes with time is 

 necessarily getting older? 



Montagna: Perhaps, but suppose one were to take Dr. Krohn's 

 suggestion and use a suspension of epidermal cells, they might do a 

 dozen different things. Among other things they might become kera- 

 tinized, store fat, divide or do many other things. 



Huggett: In actual fact that is just what we have not been clear about 

 on our minds — ageing and senescence. I think the general principles 

 involved are food for the subsequent discussion. 



Parkes: There is one point about the red cell: it appears to be more 

 typical than you might think, because Lovelock's work on the red cell 

 provides a perfectly good explanation of the well-known fact that the use 

 of media containing egg-yolk prevents temperature shock in bull sperm. 



Krohn: You said, I think, that it was difficult to make a red cell 

 demonstrate thermal shock? 



Parkes: Yes, that is true. 



Krohn: Is that again a possibility that thermal shock depends on the 

 presence of the nucleus ? 



Parkes: I do not know about that. It shows thermal shock only in 

 abnormal media — in hypertonic media. 



Huggett: Are there any essential points of fundamental difference 

 between the mammalian non-nucleated red cell and the avian nucleated 

 red cell, Dr. Mollison? 



Mollison: I think one very important point is that the non-nucleated 

 red cell is thought to get its energy from anaerobic glycolysis, whereas 

 in the nucleated cells it depends upon an aerobic process. 



Huggett: What does the red cell do with oxygen then if it gets energy 

 that way? 



Mollison: I do not know. I know only that it has been shown by 

 Maizels that in nucleated red cells cation transport depends upon 

 respiration and can, for example, be inhibited by cyanide. 



Amoroso: Did I understand Dr. Mollison to say that the red cell is 

 at a disadvantage in respect to enzyme synthesis? 



Mollison: I think that may be the whole point if I understand recent 

 work correctly; that is, mature red cells are thought not to be able to 

 synthesize enzymes. 



Amoroso : But then you say that reticulocytes have a greater capacity 

 to do this? 



