The Yellow River delta formed from the convergence of the Yellow River mouth and the Bohai Sea possesses a unique wetland environment different from both the sea and the land. This special ecosystem is rich in salt-and alkali-tolerant microorganisms. By means of an integrated chemical and antibacterial screening method, a salt-tolerant fungal strain,rnAspergillus terreus OUCMDZ-1925 was isolated and identified from the internal organs of Chelon haematocheilus from the Yellow River estuary, Dongying, Shandong, China. The metabolites of A. terreus OUCMDZ-1925 in solid state fermentation (rice medium) showed antibacterial effects on Bacillus subtilis. Chemical investigation resulted in the isolation and identification of (+)-butyrolactone I (1) with high yield (2.5g/kg), along with the other four minor polyketides, butyrolactone IV (2), butyrolactone II (3), butyrolactone III (4) and methyl 2,4-dihydroxy-3,5,6-trimethylbenzoate (5). Compounds 1-3 and 5 showed strong antibacterial effects on Staphylococcus aureus (ATCC 51650) with MIC values of 0.31μg/mL (positive control, ciprofloxacin, MIC 0.16μg/mL). The moderate antibacterial activities were first observed for compounds 1 and 2 against Enterobacter aerogenes (ATCC 13408), and for compounds 1 and 3 against Bacillus subtilis (ATCC 93151) with MIC values of 6.25μg/mL and 12.50μg/mL, respectively (positive control, ciprofloxacin, MIC 1.25μg/mL and 5.0μg/mL, respectively). In addition, compounds 1-5 and 4 displayed weak antibacterial effects on Escherichia coli (ATCC 25922) and S. aureus (ATCC 51650), respectively.%作者利用化学与生物活性相集成的筛选方法,从采自黄河三角洲地区——东营黄河口的梭鱼Chelon haematocheilus的内脏中分离鉴定了1株耐盐真菌土曲霉Aspergillus terreus OUCMDZ-1925,其发酵产物具有抗枯草芽孢杆菌活性.进一步采用色谱分离、波谱鉴定,从其固体发酵(大米培养基)中分离鉴定了5个化合物,即右旋丁内酯Ⅰ(1)、丁内酯Ⅳ (2)、丁内酯Ⅱ (3)、丁内酯Ⅲ (4)和3,5,6-三甲基-2,4-二羟基苯甲酸甲酯(5).并发现化合物1-3和5对金黄色葡萄球菌(ATCC 51650)有强的抑菌活性(最小抑菌浓度均为0.31μg/mL,阳性对照环丙沙星的最小抑菌浓度为0.16μg/mL),化合物1和2对产气杆菌(ATCC 13408)以及化合物1和3对枯草芽孢杆菌(ATCC 93151)有中等的抑菌活性(最小抑菌浓度分别为6.25μg/mL和12.50μg/mL,阳性对照环丙沙星的最小抑菌浓度分别为1.25μg/mL和5.0μg/mL),化合物1-5对大肠杆菌(ATCC 25922)以及化合物4对金黄色葡萄球菌(ATCC 51650)有弱的抑制活性,且化合物1的产量高,达2.5g/kg,为其后续研究提供了新的药源.
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