Accession Number : AD0721393

Title :   Effects of Hyperoxia on Oxidized and Reduced NAD and NADP Concentrations in Escherichia coli.

Descriptive Note : Technical rept. no. 2, Jan 70-31 Mar 71,

Corporate Author : MISSOURI UNIV COLUMBIA

Personal Author(s) : Brunker,Robert L. ; Brown,Olen R.

Report Date : APR 1971

Pagination or Media Count : 31

Abstract : The concentrations of the pyridine nucleotide coenzymes were measured after exposure of Escherichia coli to various partial pressures of oxygen to determine if changes in the intracellular pool were associated with the toxic effects of hyperoxia. In minimal medium with acetate as the sole carbon source at 37 deg. in air, the concentrations of the coenzymes in thousands of molecules/bacterium were: NAD, 469 plus or minus 17; NADH, 158 plus or minus 11; NADP, 55 plus or minus 5; and NADPH, 50 plus or minus 8. Oxygen at 1 atmosphere increased the generation time by 33% compared to air and NAD was decreased by 30%; the other coenzymes were unchanged. Oxygen at 6 atmospheres was immediately bacteristatic and 2 hours of exposure produced a 62% decrease in NAD; again the other coenzymes were unchanged. The reduction in NAD concentration could be rate-limiting for growth and respiration; however, NADPH was present in normal concentration in oxygen-inhibited bacteria and should not be limiting for reductive steps in synthesis. (Author)

Descriptors :   (*COENZYMES, *HIGH PRESSURE), (*ESCHERICHIA COLI, COENZYMES), (*OXYGEN, TOXICITY), BACTERIA, STRESS(PHYSIOLOGY), ENZYMES, OXIDOREDUCTASES, PYRIDINES, NUCLEOTIDES, GROWTH(PHYSIOLOGY), INHIBITION, RESPIRATION

Subject Categories : Biochemistry
      Stress Physiology

Distribution Statement : APPROVED FOR PUBLIC RELEASE