Killing of Mycolic Acid-Containing Bacteria Aborted Induction of Antibiotic Production by Streptomyces in Combined-Culture.
Killing of Mycolic Acid-Containing Bacteria Aborted Induction of Antibiotic Production by Streptomyces in Combined-Culture.
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联合培养中，杀灭含分枝菌酸的细菌可阻止链霉菌产生抗生素的诱导。
DOI：
10.1371/journal.pone.0142372
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发表时间：
2015
期刊：
影响因子：
3.7
通讯作者：
Onaka H
中科院分区：
文献类型：
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作者：
Asamizu S;Ozaki T;Teramoto K;Satoh K;Onaka H
链霉菌与含分枝菌酸细菌（MACB）的共培养，我们称之为“联合培养”，改变了链霉菌的次生代谢模式，是发现生物活性天然产物的有用方法。在我们研究确定 MACB 诱导因素的过程中，我们之前观察到浅青紫链霉菌中色素的产生不是由培养物提取物或分枝菌酸等因素诱导的。尽管由于 MACB，培养条件发生了动态变化，但在两个菌落直接接触的有限区域中观察到变青链球菌色素产生的激活。这表明细胞的直接附着是必要条件，并且 MACB 细胞膜上的成分可能在变铅青链球菌的反应中发挥重要作用。在这里，我们检查了这种反应是否受到死 MACB 的影响，死 MACB 具有组装在外细胞膜上的完整霉菌酸。使用甲醛固定和 γ 辐射来制备保留其形状的死细胞和三种 MACB 物种的分枝酸：肺冢菌、红平红球菌和混色红球菌。培养测试证实变青链球菌对三种 MACB 的完整死细胞没有反应。通过扫描电子显微镜 (SEM) 对组合培养物的观察表明，活 MACB 与变青链球菌菌丝体的粘附是一种显着的相互作用，导致共聚集的形成。相反，在SEM分析中，没有观察到死细胞粘附。因此，活 MACB 细胞的直接附着被认为是导致链霉菌在联合培养中改变其专门代谢的可能因素之一。
Co-culture of Streptomyces with mycolic acid-containing bacteria (MACB), which we termed “combined-culture,” alters the secondary metabolism pattern in Streptomyces and has been a useful method for the discovery of bioactive natural products. In the course of our investigation to identify the inducing factor(s) of MACB, we previously observed that production of pigments in Streptomyces lividans was not induced by factors such as culture extracts or mycolic acids. Although dynamic changes occurred in culture conditions because of MACB, the activation of pigment production by S. lividans was observed in a limited area where both colonies were in direct contact. This suggested that direct attachment of cells is a requirement and that components on the MACB cell membrane may play an important role in the response by S. lividans. Here we examined whether this response was influenced by dead MACB that possess intact mycolic acids assembled on the outer cell membrane. Formaldehyde fixation and γ-irradiation were used to prepare dead cells that retain their shape and mycolic acids of three MACB species: Tsukamurella pulmonis, Rhodococcus erythropolis, and Rhodococcus opacus. Culturing tests verified that S. lividans does not respond to the intact dead cells of three MACB. Observation of combined-culture by scanning electron microscopy (SEM) indicated that adhesion of live MACB to S. lividans mycelia were a significant interaction that resulted in formation of co-aggregation. In contrast, in the SEM analysis, dead cells were not observed to adhere. Therefore, direct attachment by live MACB cells is proposed as one of the possible factors that causes Streptomyces to alter its specialized metabolism in combined-culture.