【作者】 周少波；

【导师】 叶小利；

【作者基本信息】 西南大学 ， 生物化学与分子生物学， 2008， 硕士

【摘要】 本文以合成鱼腥草素同系物(HOU-Cn,n=8,10,12)为模型化合物,以金黄色葡萄球菌和枯草杆菌为微生物模型,系统的研究了HOU-Cn对G~+的抗菌活性及其变化规律;同时以枯草杆菌为微生物模型初步研究了HOU-Cn对G~+的抗菌机理。用纸片法进行体外抑菌试验发现,HOU-Cn对金黄色葡萄球菌和枯草杆菌的抑菌活性都较强,但对枯草杆菌的抑菌活性最大。通过试管稀释法可以分别求得HOU-Cn对金黄色葡萄球菌和枯草杆菌的最小抑菌浓度(MIC)和最小杀菌浓度(MBC)。实验结果表明,HOU-C8,HOU-C10,HOU-C12对金黄色葡萄球菌的MIC分别为50mg/l,50mg/l,25mg/l;对枯草杆菌的MIC分别是35mg/l,20mg/l,20mg/l;对金黄色葡萄球菌的MBC分别为160mg/l,80mg/l,55mg/1,对枯草杆菌的MBC分别为150mg/l,70mg/l,50mg/l。与表面活性的研究结果比较发现,HOU-Cn的抑菌能力与其疏水能力呈正相关,即随着烷酰基碳原子数的增加抗菌能力增强。荧光偏振法检测HOU-Cn对枯草杆菌细胞膜流动性的影响,结果显示荧光偏振值P几乎没有变化,表明HOU-Cn在实验浓度下对细胞膜流动性没有影响;荧光分析法研究表明HOU-Cn通过疏水作用与膜蛋白结合,并使膜蛋白构象发生变化;通过SDS-PAGE电泳和气相色谱法发现,HOU-Cn能影响蛋白质和脂肪酸的合成。并且,HOU-Cn对细胞膜构象、蛋白质和脂肪酸合成的影响都随碳原子数的增加而增强。因此,推断出HOU-Cn通过使膜蛋白构象发生变化能使生物合成的关键酶失活,影响蛋白质和脂肪酸的合成。随着HOU-Cn浓度的增加,能引起细菌破裂死亡,进而发挥抑菌作用。更多还原

【Abstract】 To evaluation antibacterial activity of houttuyfonate homologues(HOU-Cn,n=8,10,12),bacteria such as Staphylococcus aureus and Bacillus subtilis were used as target microbes.The Bacillus subtilis was used as microbes model to research antibacterial mechanism for G~+ bacteria.The experiment of paper disc method showed that Staphylococcus aureus and Bacillus subtilis were sensitive to HOU-Cn,but Bacillus subtilis was more sensitive.Further test with Staphylococcus aureus and Bacillus subtilis by tuber dilution method indicated that the minimum antibacterial concentration(MIC)of HOU-C8,HOU-C10 and HOU-C12 for Staphylococcus aureus were:50mg/l,50mg/l and 25 mg/l;and for Bacillus subtilis were 35mg/l,20mg/l and 20mg/l.MBC for Staphylococcus aureus were:160mg/l,80mg/l and 55mg/l;and for Bacillus subtilis were 150mg/l,70mg/l and 50mg/l,respectively.Compared with the result of surface activity study,it included that the antibacterial activity of HOU-Cn was proportional to their hydrophobic activity.The results of HOU-Cn on the membrane lipid fluidity experiment showed that no significant change in membrane lipid fluidity of Bacillus subtilis;the fluorescence experiments indicated that HOU-Cn directly bound to membrane proteins of G~+ bacteria by hydrophobic interaction,and made the conformation of membrane protein change;SDS-PAGE electrophoresis and GC found that there was significant.change in protein and fat acid synthesis.At the same time,the effects of HOU-Cn on cell membrane protein conformation,protein and fatty acid synthesis increased with the length of carbon chain increasing.It speculated that the antibacterial activity of HOU-Cn was mainly related to the changes in the conformation of those proteins caused by HOU-Cn,leading key enzyme to lose its function and effect protein and fat acid synthesis.With HOU-Cn concentration increased,the bacteria would die.更多还原