82 FERTILIZATION 



which ^-P had been added), after f., until after second cleavage, 

 and then slowly. U. caupo (Brooks & Chambers, 1954). 



These eggs are very variable in their respiratory response to 

 fertilization (Tyler & Humason, 1937). 



(2.3) Rate of P entry from external medium (to which ^^p had 

 been added) and incorporation in acid labile fraction much faster 

 after f. (accumulation, not exchange). P. miliaris (Lindberg, 

 1948). 



(2.4) f. eggs accumulate P fast, o-oo3-o-oo4 mg P/ml. f. eggs/ 

 min., from external medium (to which ^-P had been added), u. 

 eggs do not, though P exchange occurs. Increase in ATP content 

 70-90 min. after f. at expense of inorganic P. S. purpuratus, 

 S. franciscanus, L. pictiis (Chambers & White, 1949*, 1954)- 



(2.5) No change in ATP content after f. (1-20-1 -45 mg/ml. in 

 A. forbesi). S. droebachiensis, A. forbesi (Chambers & Mende, 



i953«)- 



Increased synthesis after fertilization might be balanced by 

 increased utilization. 



(2.6) ATPase activity in f. egg homogenates twice that in u. 

 egg homogenates. S. purpuratus (Connors & Scheer, 1947). 



This may be due to Ca release at fertilization (see 4). 



(2.7) Increase in arginine phosphate and decrease, 32%, in 

 inorganic phosphate, app. 5 min. after f., the latter being mainly 

 accounted for by the former. No change in ATP. S. droebachiensis 

 (Chambers & Mende, 19536). 



This paper contains a discussion of the contrary results obtained by 

 Runnstrom (1933), Zielinski (1939), and Orstrom & Lindberg (1940), 

 using the eggs of Faracentrotus lividiis. The authors conclude that the 

 change in inorganic P might have taken place when these eggs were 

 fertilized, but that, because of their higher inorganic P content 

 (x 15-30), it might have been missed. The synthesis of arginine 

 phosphate occurs precisely at the time of the transient increase in Go 

 uptake and acid production, see Fig. 13. Although the authors suggest 

 that the energy for the synthesis is derived from carbohydrates, the 

 low R.Q. at this time is difficult to reconcile with this view. The 

 authors also made one interesting observation on an abnormally con- 

 centrated egg suspension, in which the eggs developed pathologically. 

 In this case, there was no decrease in inorganic P and no synthesis of 

 arginine phosphate after fertilization. 



"Ps 



