RESPIRATION OF A COLORLESS FLAGELLATE, ASTASIA KLEBSII

Abstract

Reap, of conc, cell suspensions of A. klebsii, prep. from pure cultures, was detd. by the Warburg direct method at 25.2[degree] C, usually at pH 5.8. Cells in inorganic medium showed an early period of declining resp., followed by an approx. constant period. During the constant period, old (stationary-phase) cells consumed about 1.9 cu. mm. (O2/hour/million cells, and young (logarithmic-phase) cells consumed about 3.8 cu. mm. 02/hour/million cells. Of numerous organic compounds tested, only formate, acetate, propionate, ethyl alcohol, and hexose-diphosphate produced a definite increase in O2 consumption, the greatest increase occurring in acetate. In inorganic medium, resp. was approx. the same between pH 4.5 and pH 7.9; in acetate, resp. was the same at pH 5.8 and pH 7.9, and much lower at pH 4.5. The R. Q. was 1 in acetate, and slightly < 1 in inorganic medium. The presence of cytochrome in the cells was detd. spectroscopically. The highest non-toxic conc. of cyanide ([image]/100) produced about 95% inhibition of resp. in acetate, and a lesser degree of inhibition in inorganic medium. The highest non-toxic conc. of azide ([image]/1000) inhibited nearly 90% of the resp. in acetate, but had no inhibitory effect on resp. in inorganic medium.