The role of DNA polymerase I and the rec system in survival of bacteria and bacteriophages damaged by the photodynamic action of acridine orange

Autor: F. Paula Imray, Donald G. MacPhee
Rok vydání: 1973
Předmět:
Zdroj: Molecular and General Genetics MGG. 123:289-298
ISSN: 1432-1874
0026-8925
DOI: 10.1007/bf00433647
Popis: The effect of acridine orange (AO)-sensitized photodynamic treatment (PD) was studied in various repair-deficient mutants of Salmonella typhimurium and Escherichia coli. Bacteria of either species carrying mutations in the polA gene and hence deficient in the enzyme DNA polymerase I were significantly more sensitive to PD-killing than polA + parent bacteria or phenotypically POL+ revertants of the polA strains (selected on the basis of resistance to methyl methanesulphonate). It therefore appears that DNA polymerase I plays an important role in cellular recovery from PD treatment. E. coli carrying a mutation in the recA gene was also more sensitive to PD-treatment than its parent strain, as was S. typhimurium carrying a mutation of the recA type. In S. typhimurium the rec mutant was somewhat less sensitive to PD-killing than the pol mutant even although it is much more sensitive to ultraviolet killing. E. coli strains with mutations in the recB and recC genes were intermediate in PD sensitivity between the recA and the parent strain. S. typhimurium and E. coli bacteria with mutations in the polA and recA genes showed reduced ability to host-cell reactivate PD-damaged bacteriophages ES 18 and λc1, indicating that the polA + and recA + gene products also contribute to repair of bacteriophages damaged by PD treatment. It is suggested that the recombinational repair process is less important for recovery from PD than for recovery from UV, and that the primary contribution of the rec genes to recovery from PD may be in repair of single-strand gaps by repair resynthesis.
Databáze: OpenAIRE
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