Cytochrome Oxidase Activity in Blastocladiella emersoniil

Studies of cytochrome oxidase in isolated mitochondris of Blastocladiella emersonii Cant. and Hyatt show that the enzyme was present in zoospores and throughout the development of ordinary colorless sporangia and of resistant sporangia. The enzyme activity was present in KCl, NaCl, NH4Cl, and KHCO3 induced resistant sporangia, and was shown to be as active or more active than the enzyme found in ordinary colorless sporangia and zoospores. Interfering substances causing difficulties in the measurement of cytochrome oxidase activity were found in whole cell homogenates of KHCO3 grown resistant sporangia, but not in KCl, NaCl, or NH4Cl grown ithalli. These substances could be removed by dialysis or by sedimentation of the mitochondria. Blastocladiella emerson ii, a non-filamentous water mold, forms 2 morphologically distinct types of thalli. The resistant sporangiate thalli (RS) have thick, pitted, chitinous walls and are orange-brown in, color. The ordinary colorless sporangiate thalli (OC) have thin, non-pitted walls and no pigmentation. Under suitable conditions both sporangial types cleave their protoplasts into uniflagellate zoopores. The RS thalli are metabolically different from the OC thalli. Cantino (3) found that in RS thalli induced with bicarbonate,. there was a decrease in oxygen uptake and a loss of certain enzymes including cytochrome oxidase. He concluded that these differences in enzymatic activity were due to the lack of formation of the enzymes rather than to an inhibition of the