Vanitha P R, Somashekaraiah Rakesh, Divyashree S, Pan Indranil, Sreenivasa M Y
Department of Studies in Microbiology, University of Mysore, Mysuru, India.
Maharani's Science College for Women, Mysuru, India.
Front Microbiol. 2023 Jun 14;14:1192449. doi: 10.3389/fmicb.2023.1192449. eCollection 2023.
The primary objective of this study was to assess the probiotic attributes and antifungal activity of lactic acid bacteria (LAB) against the fungus, . Among the 20 isolates screened for their antifungal attributes, isolate MYSN7 showed strong antifungal activity and was selected for further analysis. The isolate MYSN7 exhibited potential probiotic characteristics, having 75 and 70% survival percentages in pH3 and pH2, respectively, 68.73% tolerance to bile, a moderate cell surface hydrophobicity of 48.87%, and an auto-aggregation percentage of 80.62%. The cell-free supernatant (CFS) of MYSN7 also showed effective antibacterial activity against common pathogens. Furthermore, the isolate MYSN7 was identified as by 16S rRNA sequencing. Both MYSN7 and its CFS exhibited significant anti- activity in which the biomass of the fungal pathogen was negligible after 14 days of incubation with the active cells of probiotic culture (10 CFU/ml) and at 6% concentration of the CFS. In addition, the CFS inhibited the germination of conidia even after 72 h of incubation. The minimum inhibitory concentration of the lyophilized crude extract of the CFS was observed to be 8 mg/ml. Preliminary characterization of the CFS showed that the active component would be organic acids in nature responsible for antifungal activity. Organic acid profiling of the CFS using LC-MS revealed that it was a mixture of 11 different acids, and among these, succinic acid (9,793.60 μg/ml) and lactic acid (2,077.86 μg/ml) were predominant. Additionally, a scanning electron microscopic study revealed that CFS disrupted fungal hyphal structure significantly, which showed scanty branching and bulged terminus. The study indicates the potential of MYSN7 and its CFS to control the growth of . Furthermore, studies need to be conducted to explore its possible applications on skin infections.
本研究的主要目的是评估乳酸菌（LAB）对真菌的益生菌特性和抗真菌活性。在筛选出具有抗真菌特性的20株分离株中，分离株MYSN7表现出较强的抗真菌活性，并被选作进一步分析。分离株MYSN7展现出潜在的益生菌特性，在pH3和pH2环境中的存活率分别为75%和70%，对胆汁的耐受性为68.73%，细胞表面疏水性适中，为48.87%，自聚集率为80.62%。MYSN7的无细胞上清液（CFS）对常见病原体也显示出有效的抗菌活性。此外，通过16S rRNA测序将分离株MYSN7鉴定为 。MYSN7及其CFS均表现出显著的抗 活性，在与益生菌培养物的活性细胞（10 CFU/ml）孵育14天以及在CFS浓度为6%的情况下，真菌病原体的生物量可忽略不计。此外，即使在孵育72小时后，CFS仍能抑制分生孢子的萌发。观察到CFS冻干粗提物的最低抑菌浓度为8 mg/ml。CFS的初步表征表明，活性成分本质上是负责抗真菌活性的有机酸。使用LC-MS对CFS进行有机酸分析表明，它是11种不同酸的混合物，其中琥珀酸（9,793.60 μg/ml）和乳酸（2,077.86 μg/ml）占主导地位。此外，扫描电子显微镜研究表明，CFS显著破坏了真菌菌丝结构，表现为分支稀少和末端膨大。该研究表明MYSN7及其CFS在控制 生长方面具有潜力。此外，需要进行进一步研究以探索其在皮肤感染方面的可能应用。
