Mondal Soma, Ravishankar Rai V
Department of Studies in Microbiology, University of Mysore, Manasagangotri, Mysuru, Karnataka, 570006, India.
J Genet Eng Biotechnol. 2021 Feb 24;19(1):36. doi: 10.1186/s43141-021-00135-0.
Endophytic actinomycetes are well known for their diverse bioactive entities and considered as an important source for drug development research.
We isolated and identified four potential endophytic Streptomyces species, i.e., Streptomyces misionensis MI22, Streptomyces roietensis MI24, Streptomyces glaucescens MI29, and Streptomyces sp. MI04 inhabiting Madhuca insignis by its characteristic morphological features and 16S rRNA gene sequence analysis. S. misionensis MI22 exhibits a broad spectrum of anti-microbial activity against methicillin-resistant Staphylococcus aureus (25.00 ± 1.00 mm) followed by Bacillus subtilis (23.66 ± 0.57 mm), Escherichia coli (22.00 ± 0.00 mm), and Candida albicans (18.00 ± 0.00 mm). Minimum inhibitory concentrations of the ethyl acetate fraction of S. misionensis MI22 against test pathogens were ranged from 25 to 100 μg/mL. Indeed, strain MI22 also exhibited significant anti-proliferative activity against HeLa cell line with IC value 98 μg/mL and showed no cytotoxicity effect to the normal human embryonic kidney cell line in the MTT assay. The anti-microbial metabolites from strain MI22 were detected at R 0.55 as depicted by the inhibition zone on the intensive band in TLC-bioautography assay.
The study indicates that, anti-microbial metabolites of these endophytic Streptomyces species, especially S. misionensis MI22 as a prolific source to discover novel bioactive metabolites to combat multidrug-resistant pathogens.
内生放线菌以其多样的生物活性物质而闻名，被认为是药物开发研究的重要来源。
我们通过其特征性形态特征和16S rRNA基因序列分析，从铁力木中分离并鉴定出四种潜在的内生链霉菌，即米申链霉菌MI22、罗耶链霉菌MI24、浅灰链霉菌MI29和链霉菌属MI04。米申链霉菌MI22对耐甲氧西林金黄色葡萄球菌表现出广谱抗菌活性（25.00±1.00毫米），其次是枯草芽孢杆菌（23.66±0.57毫米）、大肠杆菌（22.00±0.00毫米）和白色念珠菌（18.00±0.00毫米）。米申链霉菌MI22乙酸乙酯馏分对测试病原体的最低抑菌浓度范围为25至100μg/mL。事实上，菌株MI22对HeLa细胞系也表现出显著的抗增殖活性，IC值为98μg/mL，并且在MTT试验中对正常人胚肾细胞系没有细胞毒性作用。在TLC-生物自显影试验中，菌株MI22的抗菌代谢产物在R 0.55处被检测到，如密集条带上的抑制区所示。
该研究表明，这些内生链霉菌物种的抗菌代谢产物，尤其是米申链霉菌MI22，是发现对抗多重耐药病原体的新型生物活性代谢产物的丰富来源。
