Fig. 8. Effect of enzymatic treatment with tryptophanase on bioactivity of egg-conditioned sea water (ESW). Active ESW solutions were incubated with the enzyme tryptophanase, which cleaves the indole ring from L-tryptophan; solutions were boiled to quench the reaction after 10 min. In one positive control (boiled ESW), ESW solutions were boiled without enzyme, to determine effects of the deactivating step in enzyme treatments. In a second positive control (ESW+denatured enzyme), enzyme was added to ESW and immediately boiled, to ensure that the presence of denatured enzyme did not affect sperm behavior. Negative controls were run in filtered sea water (FSW). Values are means ± S.E.M.; means linked by a horizontal bar did not differ significantly (Scheffé test, P<0.05). (A) Change in sperm swim speed in response to tested solutions. (B) Change in cell density due to sperm chemotaxis.