Aerobic adaptation in yeast. I. Changes in metabolic intermediates during a step-down anaerobic-aerobic transfer

Early investigation into the mechanism of mitochondriogenesis in the facultative anaerobe Saccharomyces cerevisiae used anaerobic-aerobic transitions as model systems to study the in vivo assembly of these oxidative organelles. This methodology has become entrenched in the early literature and as a result a definitive study has been undertaken utilizing this protocol (high hexose, complete medium under anaerobic growth transferred to low hexose, minimal medium with aerobic environment) to study the altered distribution of various metabolites during these transitions. Measurement of all the glycolytic, and some tricarboxylic acid intermediates during such a transition has elucidated the following points. On a qualitative basis, the metabolic controls prevalent in these growing cultures are similar to those identified in yeast under less physiological conditions. Also, the effect of anaerobic catabolism, which preconditions enzyme and pool levels in the yeast, is of paramount importance in determining the events subsequent to oxygen challenge. However, this experimental approach has severe limitations and does not lend itself to a clear-cut delineation of the events that occur during the process of mitochondriogenesis.