The influence of organic substrates and inhibitors on the induction of a respiratory oscillation in the cyanobacterium Anacystis nidulans

The rate of respiratory oxygen uptake of the cyanobacterium (blue-green alga) Anacystis nidulans oscillated under certain physiological conditions after light pulses or after addition of sodium acetate. The oscillation started either by the photosynthetic inhibition of respiration or by the stimulation of oxygen uptake caused by sodium acetate. The photosynthetic inhibition of respiration decreased the rate of oxygen uptake to about 20% of the rate in the dark.Starved cells (48 h dark) had lost the inducibility of the oscillation. In starved as well as in non-starved cells oscillations were inducible in the presence of fructose or glucose. Well developed oscillations were not promoted further. All other substances tested as substrates did not restore the inducibility of the oscillation in starved cells. The induction of the oscillation was inhibited by iodoacetamide (0.1 mM), p-hydroxymercuribenzoate (0.1 mM) and sodium fluoride (100 mM). It is suggested that a flow from glyceraldehyde-3-phosphate to the incomplete tricarboxylic acid cycle is a prerequisite for the oscillation.