Oscillations in oxygen uptake in cultures of Neurospora crassa lys 3 treated with 2′-deoxyadenosine

Abstract

The rate of oxygen uptake by exponential phase cultures of Neurospora crassa lys 3 was measured in the presence and absence of the respiratory uncoupler, carbonyl-cyanide-mchlorophenylhydrozone (CCCP). Addition of CCCP (2.45 μm) approximately doubled the organism's rate of oxygen uptake but the stimulatory effect of the uncoupler declined as the culture increased in biomass. DNA synthesis in exponential phase cultures was synchronized by 2′-deoxyadenosine (2 m M ). The rate of oxygen uptake by these ‘synchronized’ cultures exhibited damped oscillations with two respiratory peaks per ‘DNA cycle’; CCCP had maximum stimulatory effect on oxygen uptake at times of minimum rates of respiration, i.e. during ‘troughs’ in the oscillations.