【作者】 陈杰；

【导师】 张雪洪；

【作者基本信息】 上海交通大学 ， 生物化工， 2010， 硕士

【摘要】 生物农药藤黄绿菌素(Pyoluteorin,Plt)具有抑制细菌、真菌以及除草的功能,特别是抑制卵菌属真菌具有很强的活性,具有广阔的应用前景。但在生物防治过程中发现,Plt自身化学结构并不稳定,在贮存和大田使用过程中易被降解,影响其防治效果和推广使用。因此研究Plt的降解机理,并寻求延长防治效果的有效方式,是十分必要的。本论文从降解原理和应用方法两个方面着手,对Plt的降解机理和缓释制剂进行了研究,最终目的是寻找延长Plt有效防治时间的方式。在降解原理的研究方面,从本实验室所保藏的M18(rsmA-)菌株出发,发酵制备Plt样品。并对Plt降解溶液进行分析,基于HPLC、LC/MS以及核磁共振分析,对Plt降解产物进行了分析及判定,并推测出Plt的降解机理及降解途径:Plt首先失去吡咯环4号位上的Cl,然后在该C位上甲基化,并进一步分解成农药中间体2,6-二羟基苯甲酸和脯氨酸衍生物,最终环状结构分裂生成无紫外吸收的未知物。在应用方法的研究方面,借鉴了应用于医药的纳米材料,以改良农药剂型本身为切入点,从农药缓释剂型角度出发,运用HOM(直接模板)法及EISA(挥发性诱导自组装)法一步合成载有Plt的纳米介孔二氧化硅。通过改变载药量、表面活性剂的类型及浓度、反应溶剂系统等手段对Plt-SiO2的释药影响进行了研究。最后摸索出一个缓释效果较好的合成配方:使用HOM法,质量比为m(Plt:Brij56:TMOS:HCl(aq))=0.04:1.4 : 2:1,能够达到持续缓释的效果,28天释放率达到85.13(±2.03)%,通过生化稳定性实验证实,该制剂有效延长了Plt的抑菌效果。基于小角衍射、电子透镜图像及氮吸附解析实验对其进行结构表征,测定为内部具有高度有序的三维六面体立方相结构介孔材料,排布均匀的纳米级管道是载药的通道。本论文首次对新型农药Plt的降解产物进行分析,推测出Plt在紫外光下的降解途径,为提高Plt的生物防治效果打下了理论基础。并首次通过对纳米介孔二氧化硅这种农药新剂型的探索,研究提高生物农药在田间应用效力的方式,为新型农药Plt的应用奠定良好基础。更多还原

【Abstract】 Pyoluteorin (Plt) is a biological pesticide in weeding and inhibiting the growth of bacteria and fungi, especially Oomycetes. However, the instability of its chemical structure easily leads to degradation of Plt during storage and field application, which greatly limits its utilities. So it’s essential to study the mechanism of Plt degradation, or find an effective way to prolonging its biological effects. To address this purpose, the following research was designed in two parts.First, study the degradation mechanism. Plt samples with high purity (99.3%) were purified from M18 (rsmA-) bacterial strain. And then, degradated the Plt sample in pure water under ultraviolet light. Analyze the degraded products by HPLC, LC/MS, and NMR, we hypothesize possible degradation products, and base on these products we hypothesize a possible mechanisms and pathways of Plt degradation.Sencond, look for new applications. According to researches in clinical drug discovery and pesticide improvement, the“slow-release formulation of Plt-SiO2”(nanophase material of silicon dioxide loading Plt drugs) was synthesized by HOM and EISA methods. Several conditions (including drug loading, surfactant, solvent, etc) were optimized, and the final experimental formula was m(Plt:Brij56:TMOS:HC(laq))=0.04:1.4 : 2:1, synthesizing by HOM method. This formula can continuously release 85.13(±2.03)%of Plt in 28 days. The structure of the formula was further characterized using small-angle diffraction (XRD), TEM imaging, and N2 adsorption-desorption isotherms.This is the first report to study the Plt degradation pathways by analyzing the degraded products from purified Plt in several precise methods. And also this is the first report to study the synthesis of slow-release Plt formulations using nanophase materials. It is important to the further study on storage and field application of Plt.更多还原