COMPARISON OF ENERGY METABOLISM IN SEA URCHIN SPERMATOZOA BASED ON ECHINOID PHYLOGENY

摘要

In sea urchins, matured spermatozoa stored in the testis are immotile and the respiration is quite low. After being spawned in seawater, spermatozoa begin movement, and respiration is activated. Energy for swimming is made available by mitochondrialirespiration, and ATP is utilized almost exclusively by dynein ATPase by the flagellar axoneme (Gibbons & Gibbons, 1972; Christen et al., 1982, 1983). It is unlikely that sea urchin spermatozoa are capable of using an exogenous substrates for energy metabolism, since they swim in seawater in which nutrients are virtually absence. Previous studies have shown that the endogenous phospholipid content of spermatozoa decreases following the initiation of flagellar movement (Rothschild & Cleland, 1952; Mohri, 1957, 1964; Mita & Yasumasu, 1983). This suggests that sea urchin spermatozoa derive energy for movement from the oxidation of endogenous phospholipids. It has also been shown that biochemical studies are compared with the echinoid phylogenetic relationship (Suzuki et al., 1982; Mita et al, 1994a) based on morphological criteria (Shigei, 1974). It is likely that the energy production system in sea urchin spermatozoa is related to the phylogeny in the class Echinoidea.