Fedorenko V A, Golets L M, Demidchuk Iu A, Kriugel' G
I. Franko Lvov University, Ukraine.
Antibiot Khimioter. 1998;43(4):14-9.
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.
使用脉冲电泳进行的研究表明，Asel和Dral限制性内切酶分别将初始菌株卡那霉素链霉菌1的染色体DNA分离成16个和12个片段。该菌株染色体DNA的总大小为7715kb（Dral片段大小总和）至7788kb（Asel片段大小总和）。在不稳定的卡那霉素抗性突变体kan12以及对卡那霉素和庆大霉素具有更高抗性的突变体genR10中检测到了染色体DNA重排。与初始菌株卡那霉素链霉菌1和稳定突变体kanC782的DNA相比，突变体kan12缺少98kb和220kb的Asel片段，并含有额外的297kb和450kb片段。genR10的DNA缺少420kb的Asel片段，但含有额外的450kb片段。Kan12和genR10以及另外两个对上述抗生素具有抗性的突变体（genR8和genR8.1）含有决定卡那霉素链霉菌1对卡那霉素抗性的基因kmr的扩增。在抗性最强的突变体genR8.1中检测到了最强烈的扩增。
