title: Gamma-ray inactivation of conidia from heterokaryons of Neurospora crassa containing UV-sensitive mutations.
abstract: Two-component heterokaryons were formed with the fungus Neurospora crassa. The UV-sensitive mutations upr-I, uvs-4, and uvs-6 were utilized. Conidia produced by these heterokaryons were exposed to gamma-rays and survival curves were established for the three conidial fractions produced by each heterokaryon. Results showed that upr-I, when included in only one nuclear component, did not affect the sensitivity of any conidial fraction; however, when included in both components, all three conidial fractions exhibited two- to four-fold decreases in survival at the 30 krad exposure. The uvs-4 mutation, when included in one or both components, did not increase the sensitivity of any conidial fraction and appeared, in contrast, to impart a small increase in resistance to inactivation by gamma-rays. When included in only one component, uvs-6 increased the sensitivity of homokaryotic uvs-6 conidia but had no affect on the other two conidial fractions. When included in both components, uvs-6 resulted in exponential inactivation curves and at the 30 krad exposure, 100-fold decreases in survival for all three conidial fractions.
mesh_terms: D002467:Cell Nucleus; D003470:Culture Media; D004307:Dose-Response Relationship, Radiation; D005720:Gamma Rays; D006579:Heterozygote; D009154:Mutation; D009491:Neurospora / Q000528:radiation effects*; D009492:Neurospora crassa / Q000166:cytology / Q000254:growth & development / Q000528:radiation effects*; D011831:Radiation Genetics; D013172:Spores, Fungal / Q000254:growth & development / Q000528:radiation effects; D014466:Ultraviolet Rays
chemical_list: D003470:Culture Media