Comparative study of the lethal effects of near-UV light (360 nm) and 8-methoxypsoralen plus near-UV on plasmid DNA

Journal Article · Tue Jan 01 00:00:00 EST 1991 · Cellular and Molecular Biology; (United States)

OSTI ID:5011822

Paramio, J M; Bauluz, C; de Vidania, R ^[1]

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1. Unidad de Biologia Molecular, CIEMAT, Madrid (Spain)

The authors have studied the lethality produced on pBR322 by near-UV radiation and by 8-Methoxypsoralen plus near-UV (PUV treatment). Samples of pBR322 DNA were irradiated with increasing fluences of 360 nm-light either in the absence or presence of 400 molecules of 8-Methoxypsoralen (8-MOP) per plasmid molecule. They have estimated to what extent the global lethality of PUVA treatment is due to the presence of psoralen adducts in DNA or to radiation itself. In order to analyse the involvement of DNA repair mechanisms in the removal of plasmid lesions, several strains of E. coli (differing in their repair capacities) they are used as recipients of the treated plasmids. Results showed that excision and recombination participate in the repair of near-UV-induced plasmid lesions. Repair of PUV-induced lesions showed an even greater requirement of the excision pathway. Besides, a slight increase on plasmid mutation frequencies was observed after near-UV or PUV treatment in wild type and uvrA cells. Estimation of the contribution of 8-MOP to the global lethality of PUV treatment showed that only the excision pathway was involved in removing psoralen adducts from plasmid DNA, suggesting the involvement of the recombinational pathway in the repair of near-UV-derived lesions.

• OSTI ID: 5011822
• Journal Information: Cellular and Molecular Biology; (United States), Vol. 37:2; ISSN 0145-5680
• Country of Publication: United States
• Language: English

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63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
DNA
GENETIC RADIATION EFFECTS
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DNA REPAIR
PSORALEN
RADIOSENSITIVITY EFFECTS
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HETEROCYCLIC COMPOUNDS
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