Michelson A M, Vining L C
Can J Microbiol. 1978 Jun;24(6):662-9. doi: 10.1139/m78-111.
An assay procedure was developed to detect chloramphenicol production in large numbers of Streptomyces species 3022alpha isolates, and was used to screen colonies from cultures exposed to acriflavine and ethidium bromide. There was a significant rise in the proportion of low- and non-producing strains in the treated cultures. Since the organism developed resistance to acriflavine but not ethidium bromide, the effects of the latter agent were examined in more detail. Loss of chloramphenicol production was not due to mutation, nor to differential sensitivity to the drug among producing and non-producing natural variants. The response of cultures varied with age, and at least three strain types--high-, low-, and non-producers could be distinguished. A study in shaken cultures of selected isolates from the screening process established the general reliability of the screening method and showed that the assay probably sometimes failed to distinguish between low- (15-20 mg/iota) and non-producers. It indicated that the non-producer class consisted of some very low (up to 4 mg/iota) producers as well as fully negative strains, and it confirmed indications from the screening results that a non-producing isolate obtained by acriflavine treatment accumulated aromatic amines and was probably blocked in the pathway for chloramphenicol biosynthesis.
开发了一种检测方法来检测大量链霉菌3022α分离株中氯霉素的产生，并用于筛选暴露于吖啶黄和溴化乙锭的培养物中的菌落。处理后的培养物中低产和不产菌株的比例显著上升。由于该生物体对吖啶黄产生了抗性，但对溴化乙锭没有抗性，因此对后一种试剂的作用进行了更详细的研究。氯霉素产量的丧失不是由于突变，也不是由于产生产物和不产生产物的自然变体对药物的敏感性差异。培养物的反应随年龄而异，并且至少可以区分三种菌株类型——高产、低产和不产菌株。对筛选过程中选定分离株的摇瓶培养研究确定了筛选方法的总体可靠性，并表明该检测方法有时可能无法区分低产（15 - 20毫克/升）和不产菌株。结果表明，不产菌株类别包括一些产量极低（高达4毫克/升）的生产者以及完全阴性的菌株，并且证实了筛选结果中的迹象，即通过吖啶黄处理获得的不产分离株积累了芳香胺，并且可能在氯霉素生物合成途径中受阻。
