Matsubara-Nakano M, Kataoka Y, Ogawara H
Antimicrob Agents Chemother. 1980 Feb;17(2):124-8. doi: 10.1128/AAC.17.2.124.
Streptomyces lavendulae S55-B1 gave two distinct variants at an unusual high frequency: one is a beta-lactamase-nonproducing variant and the other is an Arg- variant. All of the Arg- variants concomitantly had no, or only very low, beta-lactamase activity and were unable to form aerial mycelia or spores. There was no significant linkage between the beta-lactamase activity and the other nutritional requirement which was analyzed. Two of the Arg- variants spontaneously gave Arg+ revertants at a very low frequency. The revertants, however, did not recover the beta-lactamase activity. It is suggested that the beta-lactamase gene may be capable of transposition with inactivation of the arg gene occurring frequently by insertion of the transposed element. Covalently closed circular deoxyribonucleic acid from S55-B1 was not detected by either cesium chloride-ethidium bromide buoyant density centrifugation or agarose gel electrophoresis.
薰衣草链霉菌S55 - B1以异常高的频率产生了两种不同的变体：一种是不产生β - 内酰胺酶的变体，另一种是精氨酸缺陷变体（Arg-变体）。所有的Arg-变体都没有或只有非常低的β - 内酰胺酶活性，并且无法形成气生菌丝或孢子。β - 内酰胺酶活性与所分析的其他营养需求之间没有显著的连锁关系。两个Arg-变体以非常低的频率自发产生了精氨酸恢复变体（Arg+变体）。然而，这些恢复变体并没有恢复β - 内酰胺酶活性。有人提出，β - 内酰胺酶基因可能能够转座，并且由于转座元件的插入，精氨酸基因经常发生失活。通过氯化铯 - 溴化乙锭浮力密度离心或琼脂糖凝胶电泳均未检测到来自S55 - B1的共价闭合环状脱氧核糖核酸。
