title: DNA repair and longevity assurance in Paramecium tetraurelia.
abstract: At given doses and clonal ages, ultraviolet irradiation-induced DNA damage reduced clonal life-span, but when followed by photoreactivation, extension of clonal life-span was observed. If photoreactivation preceded the ultraviolet treatment, no significant beneficial effect was detected. Because studies of others have shown that photoreactivation repair monomerizes the ultraviolet-induced cyclobutane dimers in DNA, but does not affect the other photoproducts, these results indicate that DNA damage can influence the duration of clonal life-span unless that damage is repaired. Repeated treatment with ultraviolet and photoreactivation resulted in significant mean and maximal clonal life-span extension when compared with untreated controls, and it is assumed that the rejuvenation effect was due to the correction or prevention of some age damage.
mesh_terms: D000375:Aging; D000818:Animals; D002455:Cell Division / Q000528:radiation effects; D002999:Clone Cells / Q000528:radiation effects; D004260:DNA Repair / Q000528:radiation effects; D004307:Dose-Response Relationship, Radiation; D010247:Paramecium / Q000235:genetics / Q000254:growth & development / Q000528:radiation effects*; D014466:Ultraviolet Rays