Cytochrome c oxidase as the receptor molecule for chemoaccumulation (chemotaxis) of Euglena toward oxygen

Abstract

Chemoaccumulation of Euglena gracilis toward oxygen was selectively inhibited, without concomitant effects on cell motility, by cyanide (10(-6) to 10(-4) molar) and carbon monoxide (5 x 10(-5) to 5 x 10(-4) molar). Above these concentrations, motility of the cell was imparied and the chemosensory response was inhibited. Azide did not affect chemoaccumulation even at 5 x 10(-3) molar. It is concluded that cytochrome a3 serves as the chemoreceptor molecule for oxygen-mediated behavioral responses in Euglena.