UV mutagenesis in inhibitor depleted conidia of Aspergillus nidulans.
UV treated conidia of a strain of Aspergillus nidulans (meth Gl. biAl) depleted of germination inhibitory substances have been examined for inactivation and mutation induction at groups of suppressor gene loci defining three classes of methionine revertants. An exponential decline in the colony forming ability and quadratic increase in mutation frequency (for each class of revertant) as the incident dose increased were observed. The induced mutation frequency for each class and the loss of colony forming ability of the conidia are greater in the absence than in the presence of these self-inhibitors of germination. However, the relative frequencies of the individual classes of revertants did not differ whether the inhibitory substances were present or not. Liquid holding effects leading to increases in survival and mutation have been observed, but the relative frequencies of the individual revertant classes remain unchanged.
MRC Radiobiology Unit, Harwell, Didcot, Oxon OX11 ORD, England.
B R
BR
Scott
T
T
Alderson
D G
DG
Papworth
D001233:Aspergillus nidulans / Q000235:genetics* / Q000528:radiation effects*; D015169:Colony Count, Microbial; D016296:Mutagenesis / Q000235:genetics*; D014466:Ultraviolet Rays