抄録
Photoreactivation of Escherichia coli after a low-pressure ultraviolet (UV) lamp inactivation was investigated in the presence or absence of yeast extract (YE). The YE solution was dialyzed to specify the fraction vaffecting photoreactivation. A conventional colony forming test was used to examine the survival of E. coli, while an endonuclease sensitive site (ESS) assay was also performed to determine the number of UV-induced pyrimidine dimers in the genome DNA of E. coli. In photoreactivation of E. coli, survival recovery was significantly reduced in the presence of YE. Further investigations with YE dialysates indicated that the YE components with nominal molecular weights between 1000 and 3500 were mostly responsible for repressing the survival recovery. Interestingly, ESS repair was observed even with the YE dialysate, suggesting that E. coli could not recover the survival even after the repair of ESS in the presence of YE. The results of this study indicated that the YE components were effective to repress the survival recovery of E. coli without directly affecting ESS repair during photoreactivation.
