Bulgakova V G, Kostrova O M, Sazykina S Iu, Korolev P N, Polin A N
Antibiot Khimioter. 1989 Jun;34(6):425-9.
Variants of Micrococcus lysodeikticus resistant to 100 micrograms/ml of gramicidin S with preserved resistance in subcultures on media without the antibiotic were isolated as a result of prolonged adaptation on a solid medium with increasing concentrations of gramicidin. The sensitive and resistant cells did not differ by their ability to bind gramicidin. Under the antibiotic effect permeability of the cytoplasmic membranes of the intact cells in the sensitive bacteria appeared to be impaired to a greater extent than that of the membranes of the cells in the resistant variant. Comparison of the lytic activity of gramicidin and its derivatives with respect to the protoplasts prepared with the cells of the initial and resistant variants of M. lysodeikticus revealed much higher resistance of the resistant variant protoplasts to the membrane-disorganizing effect of the preparations. Malate dehydrogenase and NADH-oxidase in the membrane preparations of the resistant variant cells differed from analogous enzymes from the membranes of the initial strain by the levels of their activity and sensitivity to gramicidin. It is likely that during adaptation of M. lysodeikticus to gramicidin significant changes in the cell cytoplasmic membranes occurred.
通过在含有浓度不断增加的短杆菌肽的固体培养基上长期适应，分离出了对100微克/毫升短杆菌肽S具有抗性且在不含该抗生素的培养基中继代培养时仍保持抗性的溶壁微球菌变体。敏感细胞和抗性细胞在结合短杆菌肽的能力上并无差异。在抗生素作用下，敏感细菌中完整细胞的细胞质膜通透性似乎比抗性变体细胞的膜通透性受到的损害更大。比较短杆菌肽及其衍生物对用溶壁微球菌初始变体和抗性变体细胞制备的原生质体的裂解活性，发现抗性变体原生质体对制剂的膜破坏作用具有更高的抗性。抗性变体细胞膜制剂中的苹果酸脱氢酶和NADH氧化酶与初始菌株细胞膜中的类似酶在活性水平和对短杆菌肽的敏感性方面存在差异。溶壁微球菌在适应短杆菌肽的过程中，细胞质膜可能发生了显著变化。
