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Rhodosporidium BANNO : Dosiseffektbeziehungen, Mutageneffektivität und Mutantenspektrum bei der Induktion Auxotrophie verursachender Mutationen durch ultraviolettes Licht und N‐Methyl‐N′‐nitro‐N‐nitrosoguanidin
Author(s) -
Böttcher F.,
Samsonova I. A.
Publication year - 1978
Publication title -
zeitschrift für allgemeine mikrobiologie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.58
H-Index - 54
eISSN - 1521-4028
pISSN - 0044-2208
DOI - 10.1002/jobm.19780180903
Subject(s) - auxotrophy , mutant , microbiology and biotechnology , enzyme , biochemistry , chemistry , purine metabolism , biology , tryptophan , mutation frequency , gene , amino acid
The kinetics, efficiency, and specificity of induction of forward mutations to auxotrophy by ultraviolet light (UV) and N‐methyl‐N′‐nitro‐N‐nitrosoguanidine (MNNG) was examined in stationary phase cells of Rhodosporidium ( Rhodotorula ) wild strain Rgl. In comparison to the spontaneous level the frequency of auxotrophic mutants was increased more than 1000 times by both mutagens, however, the mutagenic efficiency of MNNG was higher than that of UV. We found that the forward mutation rate is a linear function of the applicated UV and MNNG doses in the range to 600 J m −2 or 25 mm x min, respectively. The 35 studied biosynthetic pathways to amino acids, purines, pyrimidines, and vitamins are genetically blocked at different frequencies, but there is not any significant difference between UV and MNNG induced frequencies of mutants with a specific requirement. However, in difference to the approximately equal distribution of the MNNG‐induced nic mutants among the genetic blocks of the tryptophan‐nicotinamide pathway, UV‐induced nic mutants occurred with a higher frequency in the genes of the tryptophan pyrrolase and the 3‐hydroxykynureninase than in the genes of the other enzymes of the pathway.