title: Lethal and mutation frequency responses of Spiroplasma citri cells to UV irradiation.
abstract: The effect of UV irradiation on viability and mutant colony frequency in the Mollicute Spiroplasma citri was investigated at 3 phases of growth. The first UV-induced mutants obtained in Mollicutes were selected: xylitol-resistant (XylR) and arsenic acid-resistant mutants (ArsR). Lethal and mutation frequency responses of S. citri cells increase with the age of the cell cultures. In all UV-irradiated populations, light exposure slightly increases the number of survivors and decreases the induced mutation frequency; liquid holding conditions increase the number of both survivors and mutant colonies. This suggests that, in UV-irradiated S. citri cells maintained under liquid holding conditions, there is no dark reactivation but induction of an error-prone repair system of the SOS type. In S. citri, the error-free light and dark repair systems are inefficient. Results allow the development of a method to select UV-induced mutations usable as markers in genetic studies of Spiroplasma cells.
authors.affiliation: Laboratoire de Génétique Moléculaire, Université de Bordeaux II, Pont-de-la-Maye, France.
authors.forename: J
authors.initials: J
authors.lastname: Labarère
authors.forename: G
authors.initials: G
authors.lastname: Barroso
mesh_terms: D004307:Dose-Response Relationship, Radiation; D009154:Mutation / Q000187:drug effects*; D013149:Spiroplasma / Q000254:growth & development / Q000528:radiation effects*; D014466:Ultraviolet Rays