Antimicrobial Gageomacrolactins Characterized from the Fermentation of the Marine-Derived Bacterium Bacillus subtilis under Optimum Growth Conditions
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- 作者：Fakir Shahidullah Tareq ; Ji Hye Kim ; Min Ah Lee ; Hyi-Seung Lee ; Jong-Seok Lee ; Yeon-Ju Lee ; Hee Jae Shin
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2013
- 出版时间：April 10, 2013
- 年：2013
- 卷：61
- 期：14
- 页码：3428-3434
- 全文大小：309K
- 年卷期：v.61,no.14(April 10, 2013)
- ISSN：1520-5118
文摘
Marine bacteria are a potential source of structurally diversified bioactive secondary metabolites that are not found in terrestrial sources. In our continuous effort to search for new antimicrobial agents from marine-derived bacteria, we isolated bacterial strain 109GGC020 from a marine sediment sample collected from Gageocho, Republic of Korea. The strain was identified as Bacillus subtilis based on a 16s rRNA sequence analysis. After a 7-day fermentation of the B. subtilis strain under optimum growth conditions three new and four known secondary metabolites were discovered using chromatographic procedures, and their biological activities were evaluated against both bacteria and crop-devastating fungi. The discovered metabolites were confirmed by extensive 2D NMR and high-resolution ESI-MS data analyses to have the structures of new macrolactin derivatives gageomacrolactins 1鈥?b>3 and known macrolactins A (4), B (5), F (6), and W (7). The stereoconfigurations of 1鈥?b>3 were assigned based on coupling constant values, chemical derivatization studies, and a literature review. The coupling constants were very crucial to determine the relative geometries of olefins in 1鈥?b>3 because of overlap of the 1H NMR signals. The NMR data of these compounds were recorded in different solvents to overcome this problem and obtain accurate coupling constant values. The new macrolactin derivatives 1鈥?b>3 displayed good antibiotic properties against both Gram-positive (S. aureus, B. subtilis, and B. cereus) and Gram-negative (E. coli, S. typhi, and P. aeruginosa) bacteria with minimum inhibitory concentration (MIC) values of 0.02鈥?.05 渭M. Additionally, the antifungal activities of 1鈥?b>7 were evaluated against pathogenic fungi and found to inhibit mycelial growth of A. niger, B. cinerea, C. acutatum, C. albicans, and R. solani with MIC values of 0.04鈥?.3 渭M, demonstrating that these compounds were good fungicides.