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 morpho-logical 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.
Keywords: Fritillaria thunbergii, Endophytic fungus, Penicillium chrysogenum, Diketopiperazines, Quinazolinones
