Nejvíce citovaný článek - PubMed ID 14202271
Morphological mutants of the c type of the bacteriophage G101 (Pseudomonas aeruginosa) were isolated after mutagenesis with hydroxylamine. Complementation analysis of 27 c mutants showed that the c region is formed by at least two genes. Two types of c mutants were obtained. One of them (cI26) behaves analogously to a mutant in the gene controlling the synthesis of the repressor of phage lambda. The second type of the c mutants (cII1, cII18) specifies a gene having probably an auxiliary function in the "c" region. According to the low frequency of recombination between the genes cI26 and c II18 (1.37 recombination units), these genes responsible for lysogenization are localized in a short region of the chromosome.
A simple and speedy procedure is described for the preparation and application of nitrous acid in mutagenic experiments. The conventional incubation mixture of sodium nitrite solution with acetate buffer is replaced by an aqueous solution of nitrous acid prepared by running a solution of sodium nitrite through a column of ion exchange. The procedure eliminates also the interference of other substances. Experimental appraisal of the technique was done during the mutagenic improval of the fungus Claviceps purpurea.
- MeSH
- Claviceps účinky léků MeSH
- dusitany farmakologie MeSH
- kyselina dusitá chemická syntéza farmakologie MeSH
- metody MeSH
- mutageny * MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- dusitany MeSH
- kyselina dusitá MeSH
- mutageny * MeSH
Mutants of Streptomyces atroolivaceus blocked in the biosynthesis of mithramycin were isolated both by natural selection and after treatment with mutagenic factors (UV and gamma rays, nitrous acid). Both physical factors were more effective than nitrous acid. The selection was complicated by a high instability of isolates, out of which 20-80% (depending on their origin) reversed spontaneously to the parent type. The primary screening (selection of morphological variants and determination of their activity using the method of agar blocks) made it possible to detect only potentially non-productive strains; however, the final selection had to be performed always under submerged conditions. Fifty-four stable non-productive mutants were divided, according to results of the chromatographic analysis, in five groups differing in production of six biologically inactive metabolites (compounds A-H). The mutants did not accumulate chromomycinone, chromocyclomycin and chromocyclin. On mixed cultivation none of the pairs of mutants was capable of cosynthesis of mithramycin or new compounds differing from standard metabolites. Possible causes of the above results are discussed.
- MeSH
- Bacillus subtilis MeSH
- biotest MeSH
- dusitany farmakologie MeSH
- genetická variace * MeSH
- kyselina dusitá farmakologie MeSH
- mithramycin analýza biosyntéza MeSH
- mutageny MeSH
- nitrosoguanidiny MeSH
- radiační genetika MeSH
- Streptomyces účinky léků metabolismus účinky záření MeSH
- ultrafialové záření * MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- dusitany MeSH
- kyselina dusitá MeSH
- mithramycin MeSH
- mutageny MeSH
- nitrosoguanidiny MeSH
- MeSH
- antibiotická rezistence MeSH
- dusitany * MeSH
- kultivační média MeSH
- mikrobiální genetika * MeSH
- mutace MeSH
- mutageny MeSH
- Mycobacterium * MeSH
- streptomycin MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- dusitany * MeSH
- kultivační média MeSH
- mutageny MeSH
- streptomycin MeSH
- MeSH
- alkylační látky farmakologie MeSH
- antibiotická rezistence MeSH
- isoniazid farmakologie MeSH
- kyseliny sulfonové farmakologie MeSH
- mikrobiální genetika * MeSH
- mutageny farmakologie MeSH
- Mycobacterium cytologie účinky léků MeSH
- streptomycin farmakologie MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- alkylační látky MeSH
- isoniazid MeSH
- kyseliny sulfonové MeSH
- mutageny MeSH
- streptomycin MeSH
