Ultradian oscillation ofSaccharomyces cerevisiae during aerobic continuous culture: hydrogen sulphide mediates population synchrony

Saccharomyces cerevisiae showed an ultradian respiratory oscillation during aerobic continuous culture. Analysis of the off-gas revealed that hydrogen sulphide production also oscillated. Production was first detected at the onset of low respiration and reached a maximum (1.5 microM) prior to minimum respiratory activity. Then H(2)S concentration fell rapidly to below 0.2 microM before the onset of high respiration. Injection of respiratory oscillation perturbation agents, such as glutathione (50 microM), NaNO(2) (50 microM) or acetaldehyde (4.5 mM),() transiently increased H(2)S production above 6 microM. The synchronization properties of H(2)S were analysed to reveal that changes of oscillation period and amplitude were dependent on H(2)S concentration in culture. It is concluded that H(2)S produced during oscillation produces population synchrony by respiratory chain inhibition.