El Samak Manar, Solyman Samar M, Hanora Amro
Department of Microbiology & Immunology, College of Pharmacy, Suez Canal University, Ismailia, Egypt.
Biotechnol Rep (Amst). 2018 Jul 20;19:e00275. doi: 10.1016/j.btre.2018.e00275. eCollection 2018 Sep.
Marine invertebrates-associated microorganisms were considered to be important sources of marine bioactive products. This study aims to isolate marine invertebrates associated bacteria with antimicrobial activity from the Red Sea and test their biosynthetic potential through the detection of PKS and NRPS gene clusters involved with the production of bioactive secondary metabolites. In this respect, fifty bacterial strains were isolated from eight different Red Sea marine invertebrates and screened for their antimicrobial activity against standard pathogenic bacteria ( ATCC 25923, ATCC 25922, ATCC 6633) and yeast ( ATCC 10231) using the standard well diffusion assay. Five isolates showed antifungal activity against with no activity recorded against other pathogenic bacterial strains. On the other hand when these isolates were screened for the presence of biosynthetic gene clusters (PKS and NRPS) by PCR using five sets of degenerative primers, 60% of the isolates were shown to contain at least one type of PKS and NRPS gene clusters, which indicates the biosynthetic potential of these isolates even if the isolates didn't express any biological activity in vitro. Moreover the 16S rRNA molecular identification of the isolates reveal the biodiversity of the red sea marine invertebrates associated bacteria as they were found to belong to several bacterial groups present in Alphaproteobacteria, Gammaproteobacteria, Actinobacteria and Firmicutes.
海洋无脊椎动物相关微生物被认为是海洋生物活性产物的重要来源。本研究旨在从红海分离具有抗菌活性的海洋无脊椎动物相关细菌，并通过检测参与生物活性次级代谢产物生产的聚酮合酶（PKS）和非核糖体肽合成酶（NRPS）基因簇来测试它们的生物合成潜力。在这方面，从八种不同的红海海洋无脊椎动物中分离出五十株细菌菌株，并使用标准的孔扩散法筛选它们对标准病原菌（ATCC 25923、ATCC 25922、ATCC 6633）和酵母（ATCC 10231）的抗菌活性。五株分离株显示出抗真菌活性，对其他病原菌菌株未记录到活性。另一方面，当使用五组简并引物通过聚合酶链反应（PCR）筛选这些分离株中生物合成基因簇（PKS和NRPS）的存在时，60%的分离株显示至少含有一种类型的PKS和NRPS基因簇，这表明即使这些分离株在体外未表现出任何生物活性，它们也具有生物合成潜力。此外，对分离株的16S rRNA分子鉴定揭示了红海海洋无脊椎动物相关细菌的生物多样性，因为它们被发现属于存在于α-变形菌纲、γ-变形菌纲、放线菌纲和厚壁菌门中的几个细菌类群。
