title: Response of tobacco and Haplopappus cells to ultraviolet irradiation after posttreatment with photoreactivating light.
abstract: Experiments were performed to test whether significant amounts of pyrimidine dimers are produced in cultured cells of tobacco (Nicotiana tabacum L. var. Xanthi) and of Haplopappus gracilis by ultraviolet light in the biological dose range and whether either or both dark and light repair systems exist in these cells. Thymine-containing dimers were found to be formed quite readily in both kinds of cells, but neither kind appeared to possess the excision repair system. Results indicated that UV-induced growth inhibition of tobacco cells could be photoreactivated and that tobacco cells could monomerize UV-induced, thymine-containing dimers in the DNA. On the other hand, neither increase in growth nor monomerization of dimers was observed in the UV-irradiated Haplopappus cell culture after treatment with photoreactivating light.
authors: Natural Science Department, Michigan State University, East Lansing, Michigan, USA.
authors: J E
authors: JE
authors: Trosko
authors: V H
authors: VH
authors: Mansour
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology / Q000528:radiation effects; D002478:Cells, Cultured; D004249:DNA Damage; D018744:DNA, Plant / Q000502:physiology / Q000528:radiation effects; D004307:Dose-Response Relationship, Radiation; D031206:Haplopappus / Q000502:physiology* / Q000528:radiation effects*; D008027:Light; D011725:Pyridines / Q000378:metabolism*; D011829:Radiation Dosage; D011836:Radiation Tolerance / Q000528:radiation effects; D014026:Nicotiana / Q000502:physiology* / Q000528:radiation effects*; D014466:Ultraviolet Rays
chemical_list: D018744:DNA, Plant; D011725:Pyridines