Abstract
The distinct three-section UV fluence-mutation frequency response (MFR) curve demonstrated in Escherichia coli strain B/r WP2 thy trp and its uvrA derivative supports the SOS hypothesis and suggests that trp + revertants can arise either from isolated lesions (1DM) plus SOS induction of from two lesions in proximity (2DM). Preirradiation growth on arabinose instead of glucose converted the fluence—survival curve from highly shouldered to exponential but did not affect the three-section MFR curve. Prestarvation of the uvrA + strain for tryptophan, which drastically increases the expanse of the shoulder of the survival curve, greatly decreased both 1DM and 2DM. With the uvrA strain the increase in shoulder expanse after tryptophan prestarvation was accompanied by greatly increased 2DM but no change in 1DM. Preincubation with chloramphenicol induced an even greater increase in 2DM response than amino acid prestarvation. Nalidixic acid, which prevents DNA accumulation, eliminated the response.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
