PATHOGENICITY AND GENETIC DIVERSITY OF ALTERNARIA ALTERNATA STRAINS

对分离自紫茎泽兰的19个链格孢菌菌株的致病性进行了比较研究,并对这19个菌株和其它来源的3个菌株的5.8SrDNA及其两侧的ITS1区和ITS2区进行了序列分析.结果显示,链格孢菌菌株的致病性差异明显;21株链格孢菌菌株在5.8SrDNA及其两侧的转录间区(ITS区)的序列无差异,而与百日草链格孢菌(Alternariazinniae)的序列差异显著,表明21株链格孢菌菌株属种内变异.采用AFLP分子标记技术对21株链格孢菌的DNA扩增片段长度多态性进行了分析,结果表明,链格孢菌自然变异群体内存在很高的遗传多样性.链格孢菌菌株的相似性与菌株的地理来源有一定的相关性,但基于AFLP标记划分的AFLP类群与基于寄主病情指数划分的致病力类群间关系不相一致;起始菌株与变异菌株相似性显著,但二者和致病性的关系不显著.图2表1参18The pathogenicity of 19 strains of Alternaria alternata isolated from Eupatorium adenophorum was studied. 5.8S rDNA, ITS1 and ITS2 sequences of 22 strains from crofton weed and other plants were analyzed. The results showed that there were differences in their pathogenicity to crofton weed. The sequence analysis showed that there was no difference among 21 strains in 5.8S rDNA, ITS1 and ITS2 sequences, respectively, but the significant difference occurred between all the 21 A. alternata strains and A. zinniae. This indicated that the variance of all the 21 different strains of A. alternata was interspecific. Amplified fragment length polymorphisms (AFLP) were first used to analyze the DNA diversity of the 21 A. alternata strains. The result showed that there was a very high genetic diversity among natural and variable populations. There were some correlations between genetic similarity and geographical sources of A. alternata. The groups classified based on AFLP patterns were not associated with pathogenicity. Ancestry strains had high similarity with their original ones on genetics, but not on pathogenicity. Fig 2, Tab 1, Ref 18国家"863"项目(2001AA246012);; 国家自然科学基金(No.30170619);; 国家基础研究专项("973"项目,2002CB111402);; 江苏省自然科学基金(BK2001066);; 江苏省博士后基金8590课题资助~

酶法醇解合成2-花生四烯酸单甘酯Enzymatic synthesis of 2-arachidonoylglycerol by ethanolysis

2-花生四烯酸单甘酯（2-AG）是一种内源性大麻素，在神经、心血管和免疫等系统中具有一系列的生理活性。为实现2-AG的绿色高效制备，探究了脂肪酶催化醇解富含花生四烯酸的微生物油制备2-AG的方法。以2-单甘酯（2-MAG）含量为指标，通过单因素实验对酶法催化醇解反应条件进行了优化，并采用溶剂萃取法对产物进行纯化。结果表明：最佳反应条件为以Lipozyme 435脂肪酶为醇解脂肪酶、酶添加量4%（以油质量计）、油与无水乙醇物质的量比1∶ 40、叔丁醇为溶剂、油溶比2∶ 3、反应温度35 ℃、反应时间8 h，在最佳条件下粗产物中2-MAG含量为3363%；经溶剂萃取纯化后2-MAG的纯度达到了94.79%，其中2-AG含量为40.70%。 综上，酶法醇解富含花生四烯酸的微生物油可以获得高2-AG含量的2-MAG。2-Arachidonoylglycerol (2-AG) is an endogenous cannabinoid and exhibits a variety of biological activities in the central nervous, cardiovascular, and immune systems. To prepare 2-AG in a greener and efficient way, a lipase-catalyzed alcoholysis of microbial oil rich in arachidonic acid was used to synthesize 2-AG. With the 2-monoacylglycerol (2-MAG) content as an index, the reaction conditions of lipase-catalyzed alcoholysis were optimized by single factor experiment, and a solvent extraction method was employed to purify the product. The results showed that the optimal reaction conditions of lipase-catalyzed alcoholysis were as follows: Lipozyme 435 as alcoholysis enzyme, lipase dosage 4% (relative to oil mass), molar ratio of oil to anhydrous ethanol 1∶ 40, tert-butanol as solvent, ratio of oil to solvent 2∶ 3, reaction temperature 35 ℃ and reaction time 8 h. Under the optimal conditions, 2-MAG content in the crude product was up to 33.63%. The purity of 2-MAG after purification was up to 9479%, and the content of 2-AG was 40.70%. In conclusion, enzymatic alcoholysis of microbial oil rich in arachidonic acid can obtain 2-MAG with high 2-AG content