BIOMOLECULAR ASPECTS OF SPERMATOZOAN MOTILITY 



209 



is particularly true of flagellar gels, where the most commonly ob- 

 served feature after addition of ATP, etc., in the presence of 0.1- 

 0.2M KC1 is a change of shape. This change in shape is shown in Fig. 

 9b in a flagellar gel prepared and activated in the same way as the 

 actomyosin gel illustrated in Fig. 8. Here again some parts of the 

 specimen have contracted markedly while others have remained un- 

 changed. 



Fig. 9. Contraction of flagellar protein with ATP. (a) Gel specimen 

 from perch sperm flagella, prepared by acidification of alkaline-salt ex- 

 tract in the same way as the perch actomyosin shown in Fig. 8. In buffered 

 O.lAf KC1 solution (xlOO). (b) Gel specimen shown at (a) 10 min after 

 addition of ATP (0.003M approximately) and MgCL (0.002M) in 0.1M 

 KC1 solution, pH7.0 (xlOO). 



