OXPHOS capacity is diminished and the phosphorylation system inhibited during diapause in an extremophile, embryos of Artemia franciscana

Diapause exhibited by embryos of Artemia franciscana is accompanied by severe arrest of respiration. A large fraction of this depression is attributable to downregulation of trehalose catabolism that ultimately restricts fuel to mitochondria. This article now extends the mechanism by revealing metabolic depression is heightened by inhibitions within mitochondria. Compared to embryo lysates during post-diapause, OXPHOS capacity P is depressed during diapause when either NADH-linked substrates (pyruvate and malate) for electron transfer (ET capacity, E) through respiratory Complex I or the Complex II substrate succinate are used. When pyruvate, malate and succinate are combined, respiratory inhibition by the phosphorylation system in diapause lysates was discovered as judged by P/E flux control ratios (two-way ANOVA; F1,24=38.78; p