ABSTRACT
Humphrey (1950) has established by microspectroscopic examination the existence of cytochrome spectra in oyster spermatozoa, and has further shown that cytochrome inhibitors such as cyanide and azide suppress the oxygen uptake of these spermatozoa. In sea-urchin spermatozoa, however, Barron, Nelson & Ardao (19486) have reported a contradictory result that, though the respiration is markedly depressed by cyanide, it is completely resistant to azide, even at high concentrations. On the other hand, Utida & Nanao (1954) have reported that the normal respiration of sea-urchin sperm is not affected by sodium azide, whereas the augmented respiration caused by 2,4-dinitrophenol (DNP) is completely abolished by this inhibitor. Since the presence of the cytochrome system in sperm cells has repeatedly been confirmed in a number of animals including sea urchins (Ball & Meyerhof, 1940; Zittle & Zitin, 1942; Mann, 1945; Rothschild, 1948), it is curious that azide fails to inhibit the normal respiration of sea-urchin spermatozoa.
