[Analysis of genome rearrangements in Streptomyces kanamyceticus mutants].

Studies with the use of pulsed electrophoresis showed that Asel and Dral restriction endonucleases segregated chromosomal DNA of the initial strain Streptomyces kanamyceticus 1 into 16 and 12 fragments, respectively. The total size of the strain chromosomal DNA was from 7715 (the total of the Dral fragment sizes) to 7788 kb (the total of the Asel fragment sizes). Chromosomal DNA rearrangements were detected in the unstable Kan- mutant kan12 as well as in mutant genR10 which was characterized by higher resistance to kanamycin and gentamicin. As compared to DNA of the initial strain S.kanamyceticus 1 and the stable mutant kanC782, mutant kan12 lacked 98-kb and 220-kb Asel fragments and contained additional 297-kb and 450-kb fragments. DNA of genR10 lacked 420-kb Asel fragment but contained an additional 450-kb fragment. Kan12 and genR10 as well as two more mutants (genR8 and genR8.1) resistant to the above antibiotics contained amplifications of gene kmr determining resistance of S.kanamyceticus 1 to kanamycin. The most intensive amplification was detected in the most resistant mutant genR8.1.