Mechanism of anti-Vibrio activity of marine probiotic strain Bacillus pumilus H2, and characterization of the active substance

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• 作者：Xi-Yan Gao ; Ying Liu ; Li-Li Miao ; Er-Wei Li ; Ting-Ting Hou ; Zhi-Pei Liu
• 关键词：Anti ; Vibrio ; Bacillus pumilus H2 ; Mechanism ; Amicoumacin A ; Vibriosis control
• 刊名：AMB Express
• 出版年：2017
• 出版时间：December 2017
• 年：2017
• 卷：7
• 期：1
• 全文大小：2695KB
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Microbiology; Microbial Genetics and Genomics; Biotechnology;
• 出版者：Springer Berlin Heidelberg
• ISSN：2191-0855
• 卷排序：7

文摘

Vibriosis is a major epizootic disease that impacts free-living and farmed fish species worldwide. Use of probiotics is a promising approach for prevention of Vibrio infections in aquaculture. A probiotic anti-Vibrio strain, Bacillus pumilus H2, was characterized, and the mechanism of its effect was investigated. All 29 Vibrio strains tested were growth-inhibited by H2. The anti-Vibrio substance present in cell-free supernatant of H2 was purified and characterized by reversed-phase HPLC. Minimum inhibitory concentrations of the purified substance, determined in liquid media for various Vibrio strains, ranged from 0.5 to 64 µg/ml. Addition of the purified substance to Vibrio vulnificus culture inhibited cell growth (estimated by OD₆₀₀). Confocal microscopy and scanning electron microscopy analyses showed that surface structure of V. vulnificus cells was damaged by the purified substance, as reflected by presence of membrane holes, disappearance of cellular contents, and formation of cell cavities. The major mechanism of this anti-Vibrio activity appeared to involve disruption of cell membranes, and consequent cell lysis. The purified anti-Vibrio substance was shown to be structurally identical to amicoumacin A by MS and NMR analysis. Our findings indicate that B. pumilus H2 has strong potential for prevention or treatment of fish vibriosis in the aquaculture industry.