[Conditions for the manifestation of cyanide-resistant respiration in Pseudomonas aeruginosa].

Conditions for manifestation of cyanide-resistant respiration were studied in Pseudomonas aeruginosa. Transition of the culture from the logarithmic to the stationary phase of growth, once the source of carbon (hexadecane, glucose, citrate, succinate) or nitrogen was exhausted, was accompanied with a decrease in the sensitivity of bacterial respiration to cyanide. As soon as the limiting factor was added, the culture started to grow again and its respiration became more sensitive to the inhibitor. Changes in the sensitivity of respiration to cyanide were observed when the bacterial growth was not limited with oxygen, and cyanide was not accumulated in the cultural broth. The manifestation of cyanide-resistant respiration was caused by changes in the physiological state of the bacterium induced by the cessation of growth. The culture formed phenazine pigments while growing on all of the studied substrates. However, no correlation was established between the resistance of respiration to cyanide and the concentration of the pigments in the medium. Therefore, the resistance of respiration of Ps. aeruginosa to cyanide should be attributed to changes in the electron transport chain.