Resistance of bacterial spores to ultraviolet light
Dormant spores of gram-positive bacteria, such as the various Bacillus species, usually are more resistant to killing by ultraviolet light than are growing cells. During the first minutes of spore germination, the spore's UV resistance rises significantly before dropping to the decreased value of the vegetative cell. For all strains of all species that have been tested, the spores are considerably more UV-resistant than their corresponding growing cells. Since the killing of cells or spores by UV-radiation is due to the presence of UV-induced photoproducts in DNA, there are two major factors that might be expected to influence UV resistance. (1) the UV photochemistry of the DNA in vivo, i.e., the type of photoproducts formed in DNA by UV radiation, the quantum efficiency of their formation, and their lethality; and (2) the efficiency of the repair or removal of these photoproducts. The DNA in the dormant spores has a different UV photochemistry than does the DNA in the growing cell, while the young germinated spore's DNA may exhibit a third type of UV photochemistry. There is at least one repair system which is specific for UV photoproducts produced in the dormant spore, as well as repair systems that act on UV photoproducts formed in other stages of growth.
- Research Organization:
- Connecticut Univ. Health Center, Farmington (USA). Dept. of Biochemistry
- OSTI ID:
- 6067286
- Report Number(s):
- AD-A-204823/9/XAB
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
BACILLUS
BACTERIA
BACTERIAL SPORES
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
CHEMICAL REACTIONS
DNA
EFFICIENCY
ELECTROMAGNETIC RADIATION
GERMINATION
IN VIVO
MICROORGANISMS
NUCLEIC ACIDS
ORGANIC COMPOUNDS
PHOTOCHEMICAL REACTIONS
QUANTUM EFFICIENCY
RADIATION EFFECTS
RADIATIONS
REPAIR
SPORES
ULTRAVIOLET RADIATION