Microbiology and Microbial Biotechnology Laboratory, Department of Botany and Forestry, Vidyasagar University, Midnapore, West Bengal, India.
PLoS One. 2022 Apr 28;17(4):e0267302. doi: 10.1371/journal.pone.0267302. eCollection 2022.
Endophytes are silent microbial partners of green plants that ensure hosts' survival in odd conditions. They are known as the factories of multipotent metabolites with diverse bioactivities beneficial to modern pharmaceuticals industry. Endophytic fungi have been screened from a variety of plants and it is the first-time endophytes of club moss is being studied for production of antibacterial and antioxidative compounds. The present study reveals that Lycopodium clavatum L. harbors a potent niche of bioactive endophytic fungi and Colletotrichum alatae LCS1 was the prime producer of antibacterial and antioxidative compounds among them. The minimum inhibitory and bactericidal concentrations of ethyl- acetate culture extract ranged from 15.62 to 250 μg/mL against four Gram negative and three Gram positive microorganisms including methicillin resistant Staphylococcus aureus (ATCC-33591). Bio-autogram based screening followed by Gas chromatographic analysis confirmed the occurrence of 17 bioactive compounds and α-bisabolol is known to be the prime one. Alfa bisabolol is a unique and versatile bioactive essential oil and facilitates variety of functions. Killing kinetics data along with leakage of macromolecules into extracellular environment supports the cidal activity of the antibacterial principles at MBC values. Isolate C. alatae LCS1 was optimized by one variable at a time system coupled with response surface methodology for broad spectrum antibacterial production. The organism yielded maximum response (22.66±0.894 mm of zone of inhibition against MRSA) in 250 mL Erlenmeyer flask containing 50 mL potato dextrose broth supplemented with (g/L) glucose, 7.53; yeast extract concentration, 0.47; NaCl, 0.10 with medium pH 6.46; after 134 hours of incubation at 26°C. Optimized fermentation parameters enhanced antibacterial activity up-to more than 50% than the pre-optimized one (10.33±0.57 mm). Endophytic LCS1 was also efficient in free radical scavenging tested by DPPH, ABTS, H2O2 and FRAP assay with an IC50 values of 23.38±5.32 to 82.873±6.479 μg/mL.
内生菌是绿色植物的沉默微生物伙伴，它们确保宿主在恶劣条件下的生存。它们被称为具有多种生物活性的多功能代谢产物的工厂，这些产物有益于现代制药工业。已经从各种植物中筛选出内生真菌，这是第一次研究石松内生菌生产抗菌和抗氧化化合物。本研究表明，石松属植物蕴藏着丰富的具有生物活性的内生真菌，其中炭疽菌 LCS1 是抗菌和抗氧化化合物的主要产生菌。乙酸乙酯培养提取物的最低抑菌和杀菌浓度范围为 15.62 至 250μg/mL，对包括耐甲氧西林金黄色葡萄球菌（ATCC-33591）在内的四种革兰氏阴性菌和三种革兰氏阳性菌均有抑制作用。基于生物自显影的筛选，再结合气相色谱分析，证实了 17 种生物活性化合物的存在，其中α- 倍半水醇是主要的一种。α- 倍半水醇是一种独特而多功能的生物活性精油，具有多种功能。杀菌动力学数据以及大分子向细胞外环境泄漏支持了在 MBC 值下抗菌原理的杀菌活性。炭疽菌 LCS1 分离株通过单变量系统优化与响应面法相结合，用于广谱抗菌生产。该生物在含有 50ml 马铃薯葡萄糖肉汤的 250ml 锥形瓶中，在 26°C 下培养 134 小时后，葡萄糖（g/L）为 7.53，酵母提取物浓度为 0.47，NaCl 为 0.10，培养基 pH 值为 6.46，可获得最大响应（对耐甲氧西林金黄色葡萄球菌的抑菌圈直径为 22.66±0.894mm）。优化发酵参数使抗菌活性提高了 50%以上，比预优化的参数（10.33±0.57mm）还要高。内生菌 LCS1 在 DPPH、ABTS、H2O2 和 FRAP 测定中也具有高效的自由基清除能力，IC50 值为 23.38±5.32 至 82.873±6.479μg/ml。
