Cessation of respiration after far-ultraviolet irradiation of Escherichia coli B/r: loss of unaltered pyridine nucleotides to the medium

Journal Article · Sat Sep 01 00:00:00 EDT 1979 · Radiat. Res.; (United States)

DOI:https://doi.org/10.2307/3575185· OSTI ID:5917319

Schenley, R L ^[1]; Swenson, P A; Joshi, J G

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1. Oak Ridge National Lab., TN

Cessation of respiration of Escherichia coli B/r cells is initiated 30 min after irradiation at 254 nm and is linked to cell death. Pyridine nucleotides begin to disappear with the onset of respiratory failure and are almost completely absent from the cells by 90 min after irradiation. We studied the fate of these respiratory cofactors in a niacin-requiring mutant (RSI) grown on minimal medium containing (7-/sup 14/C)nicotinic acid. By 90 min after irradiation (52 J/m/sup 2/) nearly all of the acid-soluble radioactive counts appeared in the medium. Paper chromatographic studies and a spectrophotometric assay indicated that the material was nicotinamide adenine dinucleotide and nicotinamide adenine dinucleotide phosphate. The loss of nicotinamide adenine dinucleotide was not balanced by synthesis, despite the presence of appropriate active biosynthetic enzymes for at least 90 min after uv irradiation. Analysis of the amino acid and nucleotide pool of the cells showed that there was some loss of most of these small molecules; the levels of a few were almost completely depleted. We conclude that the pyridine nucleotides are lost from the cell to the medium and that the loss cannot be attributed to extensive general membrane damage.

• DOE Contract Number: W-7405-ENG-26
• OSTI ID: 5917319
• Journal Information: Radiat. Res.; (United States), Vol. 79:3
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ESCHERICHIA COLI
FAR ULTRAVIOLET RADIATION
BIOLOGICAL EFFECTS
NAD
NADP
BIOLOGICAL PATHWAYS
CARBON 14
CELL KILLING
INHIBITION
NUCLEOTIDES
PYRIDINE
RESPIRATION
AZINES
BACTERIA
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CARBON ISOTOPES
COENZYMES
ELECTROMAGNETIC RADIATION
EVEN-EVEN NUCLEI
HETEROCYCLIC COMPOUNDS
ISOTOPES
LIGHT NUCLEI
MICROORGANISMS
NUCLEI
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PYRIDINES
RADIATIONS
RADIOISOTOPES
ULTRAVIOLET RADIATION
YEARS LIVING RADIOISOTOPES
550201* - Biochemistry- Tracer Techniques
560400 - Other Environmental Pollutant Effects