ABSTRACT

The co-culture of microbial strains is able to activate silent biosynthetic gene clusters, leading to the production or improved production of natural compounds that do not occur under laboratory conditions. In this study, a new facultatively halophilic/psychrophilic Streptomyces sp. AC117 was initially isolated from the Sea of Oman. Then, three types of consortia were designed, using Streptomyces sp. AC117 with heat-killed bacterial pathogens, living bacterial pathogens, and environmental strains (Streptomyces and Arthrobacter). The effect of the bacterial consortia on antibacterial activity was studied through the agar well diffusion method. The addition of heat-killed bacterial pathogens to the fermentation medium increased antibacterial activity, particularly when Staphylococcus aureus was supplemented. The compound obtained from the AC117+heat-killed S. aureus was analysed by TLC and the HPLC. Elicitation through the heat-killed S. aureus led to a five-fold growth in antibacterial production. As well, the results of ¹H-NMR showed that the resulting compounds were anthraquinone derivatives. This product had a MICs of 4.1 and 6.25 μg/mL against Bacillus subtilis and S. aureus, respectively. These findings demonstrated the effectiveness of co-cultivation as a strategy to obtain secondary bioactive metabolites, hidden in the genome of Streptomyces sp. Marine ecosystems also contain a vast library of unique and novel bioproducts. The investigation of three models of bacterial co-cultures, especially heat-killed S. aureus, could thus bring about remarkable improvements in antibacterial activity. These findings indicate the potential drug use of marine microbes and the importance of culture in the activation of silent genes.

摘要

微生物菌株的共培养能够激活沉默的生物合成基因簇，从而产生或改善在实验室条件下不会发生的天然化合物的产生。在这项研究中，一种新的兼性嗜盐/嗜冷链霉菌属。AC117 最初是从阿曼海中分离出来的。然后，使用Streptomyces sp.设计了三种类型的联盟。AC117 具有热灭活细菌病原体、活细菌病原体和环境菌株（链霉菌属和节杆菌属））。通过琼脂孔扩散法研究菌群对抗菌活性的影响。向发酵培养基中添加热灭活的细菌病原体会增加抗菌活性，尤其是在添加金黄色葡萄球菌时。通过TLC和HPLC分析从AC117+热灭活的金黄色葡萄球菌获得的化合物。通过热灭活的金黄色葡萄球菌引起的抗菌产生增加了五倍。同样，¹ H-NMR的结果表明所得化合物为蒽醌衍生物。该产品对枯草芽孢杆菌和金黄色葡萄球菌的 MIC 分别为 4.1 和 6.25 μg/mL， 分别。这些发现证明了共同培养作为获得隐藏在Streptomyces sp.基因组中的次级生物活性代谢物的策略的有效性。海洋生态系统还包含一个庞大的独特而新颖的生物产品库。因此，对三种细菌共培养模型的研究，尤其是热灭活的金黄色葡萄球菌，可以显着提高抗菌活性。这些发现表明海洋微生物的潜在药物用途以及培养在激活沉默基因中的重要性。