RT Journal Article SR Electronic(1) A1 PREW, J. W. A1 GRESHAM, P. A. A1 HODKINSON, M.YR 1969 T1 Split-dose Irradiation of Escherichia coli in the Absence and Presence of Mercaptoethylamine JF Microbiology, VO 57 IS 1 SP 97 OP 104 DO https://doi.org/10.1099/00221287-57-1-97 PB Microbiology Society, SN 1465-2080, AB SUMMARY A single dose of γ-radiation to Escherichia coli b gave a semi-logarithmic dose-response curve. A second irradiation 3, 6, or 18 hr after a priming dose of 8 krad showed that the cells had become more radio-sensitive during the incubation between irradiations. When mercaptoethylamine was present during irradiation, protection against the lethal effects of the γ-radiation occurred. After a priming dose to the bacteria in the presence of the radio-protective chemical, and incubations for 3,6, or 18 hr in its absence, a second irradiation in the absence of the chemical showed them to be much more radio-resistant than the normal unprotected Escherichia coli b. This indicates that the presence of the protector during irradiation alters the type of damage induced or the development and repair of that damage., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-57-1-97