INFLUENCE OF SALINITY OF THE MEDIUM ON THE CYTOCHROME COMPOSITION, ACTIVITY, AND CYANIDE RESISTANCE OF THE RESPIRATORY-CHAIN OF THE HALOTOLERANT BACTERIUM MICROCOCCUS-VARIANS

Culture of the halotolerant bacterium Micrococcus varians with or with out an addition of NaCl leads to an appreciable change in the quantita tive content of the cytochrome components of the respiratory chain. In the presence of 1 M NaCl the total content of cytochromes is decrease d, especially in the stationary phase of growth, by a factor of 1.6. T he cytochrome a content is most substantially reduced in the exponenti al phase of growth - by a factor of two. The pattern is the reverse fo r cytochromes b and c: in the exponential phase their content is virtu ally unchanged, whereas in the stationary phase it is reduced by a fac tor of 1.4. Correspondingly, the total rate of respiration stimulated by the addition of amino acids in the presence of 1 M NaCl is decrease d by a factor of 1.7 in the exponential phase and by a factor of 1.4 i n the stationary phase. The cyanide-resistant respiration increases in the stationary phase in the absence of 1 M NaCl; this may be evidence of the functioning of alternative oxidases (of the cytochrome d type) under these conditions.