ABSTRACT
At all examined wavelength (between 360 and 620 nm, the respiratory rate in the presence of CO was enhanced by light in relation to the light fluence rate in sperm of the sea urchins, Hemicentrotus puicherrimus and Anthocidaris crassispina.
Action spectra for photo-activation of respiration in sperm of these species exhibited peaks at wavelength of 430, 530 and 570 nm. These action spectra are very similar in their profile to absorption spectrum of reduced cytochrome b. Absorption of photon energy by b-type cytochrome probably activates the redox reaction of this cytochrome to enhance the respiratory rate in these gametes.
The respiration in the presence of CO was blocked by antimycin A (AMA), and CN~ either under light irradiation or in the dark. These suggest that electron equivalent is transported from cytochrome b to cytochrome c and finally to molecular oxygen in the reaction catalyzed by CN--sensitive, CO-insensitive terminal oxidase.
