Mehetre Gajanan T, J S Vinodh, Burkul Bhushan B, Desai D, B Santhakumari, Dharne Mahesh S, Dastager Syed G
NCIM Resource Centre, CSIR-National Chemical Laboratory Pune India
Academy of Scientific and Innovative Research (AcSIR) Ghaziabad India.
RSC Adv. 2019 Mar 28;9(17):9850-9859. doi: 10.1039/c8ra09449g. eCollection 2019 Mar 22.
The bioactive potential of Actinobacteria endemic to hot springs has rarely been investigated. This study highlights the cultivable diversity and bioactivities of Actinobacteria associated with the Unkeshwar hot springs, India. Potent strains were evaluated for their biosynthetic potentials and metabolite analysis was performed using effective dereplication molecular networking tools. A total of 86 actinobacterial strains were isolated and grouped into 21 distinct genera, based on 16S rRNA gene sequence analysis. These strains included rare members such as , , , , , , , , and . In antimicrobial screening, sp. strain GH99 and sp. strain GH176 were found to be potent antimicrobial strains. The metabolic extracts of these strains exhibited strong antimicrobial activity against (NCIM 2493), (NCIM 5265), (NCIM 2098), and (NCIM 2257). The extracts also displayed strong anti-biofilm and anticancer activities against (NCIM 5029), (NCIM 5188) and breast cancer cell line MCF7, respectively. Both strains also tested positive for the presence of the PKS biosynthetic gene cluster in their genomes. To effectively delineate the secondary metabolites, the extracts were subjected to MS/MS-guided molecular networking analysis. Structurally diverse compounds including the polyketides 22-dehydroxymethyl-kijanolide (GH99 strain) and Abyssomicin I (GH176 strain) were detected in the extracts. Interestingly, Brevianamide F was detected in the extract of , which has previously been mostly found in fungal species. Other compounds such as cyclic tripeptides, Cyclo(l-Pro-d-Ile) and Cyclo(d-Pro-l-Phe), were also identified in this strain. In summary, for the first time, we explored the diversity of Actinobacteria and evaluated their bioactive potential from the Unkeshwar hot springs. The potent strains isolated in the study could be useful in drug discovery programs.
温泉特有的放线菌的生物活性潜力鲜有研究。本研究着重介绍了与印度温盖什瓦尔温泉相关的可培养放线菌的多样性及其生物活性。对具有潜力的菌株进行了生物合成潜力评估，并使用有效的去重复分子网络工具进行了代谢物分析。基于16S rRNA基因序列分析，共分离出86株放线菌菌株，并将其分为21个不同的属。这些菌株包括罕见的成员，如[此处原文缺失具体菌株名称]。在抗菌筛选中，[此处原文缺失具体菌株名称]菌株GH99和[此处原文缺失具体菌株名称]菌株GH176被发现是具有强大抗菌能力的菌株。这些菌株的代谢提取物对[此处原文缺失具体菌株名称]（NCIM 2493）、[此处原文缺失具体菌株名称]（NCIM 5265）、[此处原文缺失具体菌株名称]（NCIM 2098）和[此处原文缺失具体菌株名称]（NCIM 2257）表现出强大的抗菌活性。提取物还分别对[此处原文缺失具体菌株名称]（NCIM 5029）、[此处原文缺失具体菌株名称]（NCIM 5188）和乳腺癌细胞系MCF7表现出强大的抗生物膜和抗癌活性。这两种菌株在其基因组中也检测到聚酮合酶生物合成基因簇呈阳性。为了有效描绘次生代谢物，对提取物进行了串联质谱引导的分子网络分析。在提取物中检测到结构多样的化合物，包括聚酮化合物22-脱羟甲基-基贾诺内酯（GH99菌株）和深海霉素I（GH176菌株）。有趣的是，在[此处原文缺失具体菌株名称]的提取物中检测到了短杆菌肽F，此前大多在真菌物种中发现。在该菌株中还鉴定出了其他化合物，如环三肽环（L-脯氨酸-d-异亮氨酸）和环（d-脯氨酸-L-苯丙氨酸）。总之，我们首次探索了温盖什瓦尔温泉中放线菌的多样性，并评估了它们的生物活性潜力。本研究中分离出的具有潜力的菌株可能对药物发现计划有用。
