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
- Resource Relation:
- Other Information: Pub. in Comments on Molecular and Cellular Biophysics, Vol. 5, No. 5, 253-264(1988)
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
BACTERIAL SPORES
BIOLOGICAL RADIATION EFFECTS
ULTRAVIOLET RADIATION
BACILLUS
BACTERIA
DNA
EFFICIENCY
GERMINATION
IN VIVO
PHOTOCHEMICAL REACTIONS
QUANTUM EFFICIENCY
REPAIR
BIOLOGICAL EFFECTS
CHEMICAL REACTIONS
ELECTROMAGNETIC RADIATION
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NUCLEIC ACIDS
ORGANIC COMPOUNDS
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