Lambda-prophage induction in repair-deficient and wild type E. coli strains by gamma-rays and heavy ions.
Lambda-prophage induction in repair-deficient and wild-type E. coli strains by heavy ions and gamma-rays has been investigated. The dose dependence of the fraction of induced cells has been measured and its initial slope (lambda-induction potency) determined. The induction by gamma-rays was found to be more efficient in a polA-repair-deficient strain; the value of lambda-induction potency is zero in lexA- and recA- strains. The lambda-induction potency increased with LET for wild-type cells but remained constant in the case of polA- mutant cells. It is suggested that the DNA damage triggering the lambda-prophage induction in the case of ionizing radiation could be a type of DNA single-strand break with complex structure which cannot be repaired by fast repair processes, and which requires a substantial level of energy deposition for induction in a DNA molecule.
Bonev
M N
MN
Joint Institute for Nuclear Research, Dubna, USSR.
Kozubek
S
S
Krasavin
E A
EA
Amirtajev
K G
KG
D010582:Bacteriophage lambda / Q000528:radiation effects*; D002470:Cell Survival / Q000528:radiation effects; D004260:DNA Repair; D004269:DNA, Bacterial / Q000528:radiation effects*; D003903:Deuterium; D005720:Gamma Rays; D006371:Helium; D007477:Ions; D014775:Virus Activation / Q000528:radiation effects*
D004269:DNA, Bacterial; D007477:Ions; D006371:Helium; D003903:Deuterium