浙贝母内生真菌菌株FTJZZJ09及其抑菌活性成分

The Endophytic Fungus Strain FTJZZJ09 Isolated from the Bulbs of Fritillaria thunbergii and Its Antibacterial Metabolites

摘要:

根据菌株的形态学特征和ITS序列分析结果, 将一株来源于浙贝母新鲜鳞茎的内生真菌菌株FTJZZJ09鉴定为产黄青霉(Penicillium chrysogenum), 其在优化后的改良查氏培养基(3 g/L麦芽糖, 3 g/L蛋白胨, 0.1 g/L K2HPO4, 0.05 g/L KCl, 0.3 g/L NaNO3, 0.05 g/L MgSO4·7H2O, 0.001 g/L FeSO4·7H2O, pH 6.5)中28°C、160 r/min振摇培养7 d, 获得的发酵液具有抑菌活性。利用正相硅胶、Sephadex LH-20柱层析以及重结晶等方法, 从发酵液乙酸乙酯提取物中分离到3个具有抑菌活性的化合物, 利用质谱和核磁共振等技术将其分别鉴定为环(脯氨酸-甘氨酸)、环(脯氨酸-缬氨酸)和2-乙酰基-4 (3H)喹唑酮, 它们对枯草芽孢杆菌的生长均具有较为明显的抑制作用, MIC分别为0.8、0.8和0.4 g/L, 但对革兰氏阴性菌的生长无明显的影响。

Abstract:

In the present study, an endophytic fungus isolate FTJZZJ09, which isolated from the fresh bulbs of Fritillaria thunbergii Miq., was identified as Penicillium chrysogenum based on its morphological characters and internal transcribed spacer (ITS) sequence. After being cultured in the modified CzapeK-DoX medium (3 g/L maltose, 3 g/L peptone A, 0.1 g/L K2HPO4, 0.05 g/L KCl, 0.3 g/L NaNO3, 0.05 g/L MgSO4·7H2O, 0.001 g/L FeSO4·7H2O, pH 6.5), it can secrete antibacterial metabolites under the condition of 28°C in a rotary shaker at 160 r/min for 7 days. Three antibacterial compounds were isolated from the ethyl acetate extract of the fermentation broth by silica gel, they were elucidated as cyclo (Pro-Gly), cyclo (Pro-Val) and 2-acetyl-4 (3H) quinazolinone. All the three compounds could inhibit the growth of Bacillus subtilis with the minimal inhibitory concentration (MIC) value of 0.8, 0.8, and 0.4 g/L respectively, while they showed no apparent effects against the growth of Gram-negative bacteria.