[Decrease of spontaneous mutations in Haemophilus influenzae caused by transformation with its own DNA irradiated with near-ultraviolet light].
Transforming DNA containing the streptomycin resistance marker, was irradiated for 8 h with broad near ultraviolet light (325-400 nm) at pH 4.8, and the inactivation kinetics determined. After selection of streptomycin resistant transformants, they were grown until a turbidity of 150-200 Klett units. In these cultures we looked for new markers coming from the irradiated transforming DNA. We looked and found the novobiocin resistance marker and one that conveys to protoporphyrin IX utilization, measured as an increase in the mutation frequency of these markers in the streptomycin resistant population. In other experiments, we found a decline in spontaneous mutation frequency for the same markers in the cells transformed with irradiated DNA. This last finding rises the possibility of alterations on the mutator genes as a result of near ultraviolet irradiation.
Laboratorio de Genética molecular, Departamento de Bioquímica, Escuela Nacional de Ciencias Biológicas, I.P.N., México, D.F.
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Alarcón-Hernández
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Cabrera-Juárez
D004249:DNA Damage; D004260:DNA Repair; D004269:DNA, Bacterial / Q000235:genetics / Q000528:radiation effects*; D004352:Drug Resistance, Microbial / Q000235:genetics; D006193:Haemophilus influenzae / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D009675:Novobiocin / Q000494:pharmacology; D011524:Protoporphyrins / Q000378:metabolism; D013307:Streptomycin / Q000494:pharmacology; D014169:Transformation, Bacterial; D014466:Ultraviolet Rays
D004269:DNA, Bacterial; D011524:Protoporphyrins; D009675:Novobiocin; C028025:protoporphyrin IX; D013307:Streptomycin
Disminución de la mutación espontánea de Haemophilus influenzae por transformación con su DNA irradiado con luz del ultravioleta cercano.