Comparative studies on the energy metabolism in spermatozoa of four closely related species of sea urchins (genus Echinometra) in Okinawa.

Publisher: Zoological Society of Japan Country of Publication: Japan NLM ID: 8702287 Publication Model: Print Cited Medium: Print ISSN: 0289-0003 (Print) Linking ISSN: 02890003 NLM ISO Abbreviation: Zoolog Sci Subsets: MEDLINE

Original Publication: Tokyo, Japan : Zoological Society of Japan, c1984-

Sea Urchins/*classification ; Sea Urchins/*metabolism ; Spermatozoa/*metabolism; Animals ; Energy Metabolism ; Fatty Acids/analysis ; Fatty Acids/chemistry ; Japan ; Male ; Oxygen Consumption ; Phosphatidylcholines/chemistry ; Phospholipases A/metabolism ; Phospholipases A2 ; Sea Urchins/cytology ; Seawater ; Species Specificity ; Spermatozoa/chemistry ; Spermatozoa/ultrastructure

Sea urchins of the genus Echinometra are abundant on Okinawa reef flats in southern Japan. The Okinawan Echinometra is designated into four sympatric and closely related species: A, B, C, and D (Ea, Eb, Ec, and Ed). The sperm head size and shape gradually changes to become longer and more slender according to the following order: Ea, Eb, Ec, and Ed. To obtain information regarding speciation in Okinawan Echinometra, this study examined comparatively the energy production system of spermatozoa of Ea, Eb, Ec, and Ed. All spermatozoa contained cholesterol and several kinds of phospholipids. Glycogen, glucose, and triglyceride were present at extremely low levels. After incubation in sea-water, a decrease in the level of phosphatidylcholine (PC) was observed in all spermatozoa concomitantly with activation of motility and respiration. The hydrolysis of PC correlated with the activity of phospholipase A2. Interestingly, the amount of PC consumed, the respiratory rate, and the phospholipase A2 activity in spermatozoa of Ea and Eb were approximately two-fold higher than those of Ec and Ed. Ultrastructural studies showed that lipid bodies within mitochondria were present in the midpieces of all species of spermatozoa. They became small or disappeared after incubation in seawater. Thus, the results obtained strongly suggest that spermatozoa of Ea, Eb, Ec, and Ed all use PC located in the lipid bodies as a substrate for energy metabolism. Also, it seems likely that energy production activities in Ea and Eb spermatozoa are stronger than those in Ec and Ed. The properties of energy metabolism in different species of sea urchin may be related to their habitat.

0 (Fatty Acids)
0 (Phosphatidylcholines)
EC 3.1.1.32 (Phospholipases A)
EC 3.1.1.4 (Phospholipases A2)

Date Created: 20020720 Date Completed: 20020923 Latest Revision: 20161124

20231215

10.2108/zsj.19.419

12130819