Borisoglebskaia A N, Perebitiuk A N, Boronin A M
Antibiotiki. 1979 Dec;24(12):883-8.
High frequency of spontaneous and UV-and acridine dye-induced variants susceptible to oxytetracycline (OTC) and deprived of the capacity for synthesizing this antibiotic was observed in strain LST-118 of Actinomyces rimosus. The cells of strain LST-118 of Act. rimosus contained extrachromosomal DNA not found in its OTC susceptible variant BS87, which provides evidence in favour of participation of the extrachromosomal genetic elements in control of OTC resistance of the cells of Act. rimosus, LST-118. The OTC resistance in strain LST-118 is of inducable character. The resistance level is increasing from the beginning of the antibiotic synthesis and initially the subinhibitory concentrations of OTC in the medium were the inductors triggering cellular mechanisms ensuring resistance of the cell to the increasing concentrations of OTC in the medium. The capacity for absorption of OTC in Act rimosus is 2--3 times lower than that in E. coli. The experiments with labeled tetracycline showed that the cells of the actinomycete absorbed OTC when it was present in the medium. The absorption of the main amount of the antibiotic was registered during the first 5 minutes. The difference in absorption of OTC by the cells of the antibiotic resistant and sensitive strains was insignificant.
在龟裂链霉菌LST - 118菌株中，观察到自发产生以及紫外线和吖啶染料诱导产生的对土霉素（OTC）敏感且丧失合成这种抗生素能力的变体的高频率。龟裂链霉菌LST - 118菌株的细胞含有在其对OTC敏感的变体BS87中未发现的染色体外DNA，这为染色体外遗传元件参与控制龟裂链霉菌LST - 118菌株细胞对OTC的抗性提供了证据。LST - 118菌株中的OTC抗性具有可诱导性。抗性水平从抗生素合成开始时就不断增加，最初培养基中土霉素的亚抑制浓度是触发细胞机制的诱导剂，这些机制确保细胞对培养基中不断增加的土霉素浓度产生抗性。龟裂链霉菌吸收土霉素的能力比大肠杆菌低2 - 3倍。用标记四环素进行的实验表明，当培养基中存在土霉素时，放线菌细胞会吸收它。在最初的5分钟内记录到了抗生素主要量的吸收。抗生素抗性和敏感菌株细胞对土霉素吸收的差异不显著。
