Dataset Information

The development of the respiratory chain of Saccharomyces carlsbergensis during respiratory adaptation.

ABSTRACT: 1. Subcellular fractionation of sphaeroplasts produced at different stages during the first 4h of respiratory adaptation of anaerobically grown glucose-de-repressed Saccharomyces carlsbergensis gave mitochondrial fractions that contained all the detectable c- and a-type cytochromes. 2. The rates of cytochrome formation were studied; individual cytochromes were produced at different rates so as to give respiratory chains having widely differing cytochrome ratios. A CO-reacting haemoprotein other than cytochrome a(3) also increased throughout 8h of respiratory adaptation. 3. Even after short periods of aeration, organisms contained mitochondria in which cytochrome-cytochrome interactions and the reaction of cytochrome a(3) with O(2) proceeded at rates almost as fast as in organelles from aerobically grown cells. 4. The technique of flow-flash photolysis enabled kinetic resolution of the reoxidation of cytochromes a(3) and a to be achieved and their individual contributions to extinction changes in the Soret region were assessed. The ratio cytochrome a(3)/cytochrome a increased over the early stages of adaptation.

SUBMITTER: Cartledge TG

PROVIDER: S-EPMC1174512 | biostudies-other | 1972 Dec

REPOSITORIES: biostudies-other

ACCESS DATA

Similar Datasets

Project description:1. During anaerobic glucose de-repression the respiration rate of whole cells of Saccharomyces carlsbergensis remained constant and was insensitive to antimycin A but was inhibited by 30% by KCN. Aeration of cells for 1 h led to increased respiration rate which was inhibited by 80% by antimycin A or KCN. 2. Homogenates were prepared from sphaeroplasts of anaerobically grown, glucose de-repressed cells and the distribution of marker enzymes was investigated after zonal centrifugation on sucrose gradients containing MgCl(2). These homogenates contained no detectable cytochrome c oxidase or catalase activity. The complex density distributions of NADH- and NADPH-cytochrome c oxidoreductases and adenosine triphosphatase(s) [ATPase(s)] were very different from those of anaerobically grown, glucose-repressed cells. 3. The specific activity of total ATPase was lowered and sensitivity to oligomycin decreased from 58 to 7% during de-repression. 4. Cytochrome c oxidase and catalase activities were detectable in homogenates of cells after 10min aeration. Zonal centrifugation indicated complex, broad sedimentable distributions of all enzyme activities assayed; the peaks of activity were at 1.27g/ml. 5. Centrifugation of homogenates of cells adapted for 30min and 3 h indicated a shift of density of the major sedimentable peak from 1.25g/ml (30min) to 1.235g/ml (3 h). After 30min adaptation a minor zone of oligomycin-sensitive ATPase and 15% of the total cytochrome c oxidase activities were detected at rho=1.12g/l; these particles together with those of higher density containing cytochrome c oxidase, ATPase and NADH-cytochrome c oxidoreductase activities were all sedimented at 10(5)g-min. 6. Electron microscopy indicated that the mitochondria-like structures of anaerobically grown, glucose-de-repressed cells were similar to those of repressed cells. After 10min of respiratory adaptation highly organized mitochondria were evident which resembled the condensed forms of mitochondria of aerobically grown, glucose-de-repressed cells. High-density zonal fractions of homogenates of cells after adaptation also contained numerous electron-dense vesicles 0.05-0.2mum in diameter. 7. The possibility that the ;promitochondria' of anaerobically grown cells may not be the direct structural precursors of fully functional mitochondria is discussed.

Dataset Information

The development of the respiratory chain of Saccharomyces carlsbergensis during respiratory adaptation.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets