枯草芽孢杆菌SC-2产直链肽类代谢产物的分离纯化

Separation and Purification of Straight-chain Peptide Metabolites Produced by Bacillus subtilis SC-2

摘要:

为了研究枯草芽孢杆菌SC-2发酵液主要抗菌活性物质，以临床致病菌株耐甲氧西林金黄色葡萄球菌、痤疮丙酸杆菌、白色念珠菌等为指示菌，采用打孔法检测抑菌活性，对SC-2发酵液抑菌粗提物进行分离纯化。抑菌粗提物经硅胶柱层析、LH-20凝胶柱层析和高效液相色谱法分离制备得到抑菌单体化合物GNH-2。该物质表现出广谱的抗菌活性，在质量浓度为1 mg/mL时对白色念珠菌、大肠杆菌和大肠埃希氏菌抑菌圈直径分别为34±0.30 mm、18±0.15 mm、19±0.10 mm，对金黄色葡萄球菌、耐甲氧西林金黄色葡萄球菌和痤疮丙酸杆菌的抑菌活性分别为28±0.10 mm、30±0.10 mm、56±0.35 mm，优于同等浓度的万古霉素。通过能与茚三酮直接显色等实验结果，初步推断GNH-2属于直链的肽类化合物，为后续结构确证和新药开发提供依据。

Abstract:

In order to study the main antimicrobial substances in the fermentation liquid of Bacillus subtilis SC-2, clinical strains of pathogenic methicillin-resistant Staphylococcus aureus (MRSA), Propionibacterium acnes, and Candida albicans were used as indicator strains, antimicrobial activity was measured using the agar diffusion method, and the crude extracts of SC-2 fermentation liquid were separated and purified. The crude extract containing antimicrobial substances was separated by silica gel column chromatography, Sephadex LH-20 gel column chromatography, and high performance liquid chromatography (HPLC) to yield a monomeric compound, GNH-2, with antibacterial activity. This substance showed broad-spectrum antimicrobial activity. At a concentration of 1.0 mg/mL, the GNH-2 inhibition zone diameters against Candida albicans, Escherichia coli, and E. coli 251 were 34±0.30 mm, 18±0.15 mm, and 19±0.10 mm, respectively. The GNH-2 inhibition zone diameters against S. aureus, MRSA, and Propionibacterium acnes were 28±0.10 mm, 30±0.10 mm, and 56±0.35 mm, respectively, which were better than those of vancomycin at the same concentration. The results of ninhydrin coloration preliminarily suggested that GNH-2 was a straight-chain peptide. This work provides the basis for subsequent structure confirmation and new drug development.