Extraribosomal cyclic tetradepsipeptides beauverolides: profiling and modeling the fragmentation pathways

Profiling of cyclic tetradepsipeptides beauverolides was tested as a chemotaxonomic tool for fungal strain identification/discrimination. Two new tetradepsipeptides, beauverolides Q and R, were characterized by tandem mass spectrometry. Specific elimination of 113 atomic mass units from both protonated and sodiated molecules of beauverolides is ubiquitous for all 12 most dominant congeners evaluated in this profiling study. Reconstruction of the total ion chromatogram, according to this neutral fragment release, was used for data filtering and selectivity enhancement. Selective ring opening and fragment ion formation of beauverolide I are discussed in detail utilizing high-level theoretical modeling of the fragmentation pathways.     

球孢白僵菌毒素对昆虫体外培养细胞胞内同功酶和代谢水平的影响

用吸附法从球孢白僵菌（Beauveriabassiana）的代谢产物中提取毒素，并将毒素作用于草地夜蛾（Spodopterafrugiperda）体外培养细胞，以研究球孢白僵菌的昆虫致病机理．同功酶特异性染色结果表明，细胞中毒后，细胞内的乳酸脱氢酶、苹果酸脱氢酶、酯酶等同功酶在种类和含量上都有所减少．并发现其细胞代谢紊乱，当毒素质量浓度在0～500mg·L(－1)时，培养液中的葡萄糖和蛋白的质量浓度均随细胞中毒加深而升高．     

紫外诱变球孢白僵菌选育几丁质酶高产菌株方法的研究

本实验利用紫外线对白僵菌进行诱变，比较了不同诱变剂量对白僵菌产几丁质酶的影响，从而筛选出几丁质酶高产菌株．     

白僵菌混合剂的自动喷撒装置

针对白僵菌生物粉剂农药的特点及使用现状，开发了一种白僵菌生物混合粉剂自动喷撒装置，提出该装置的原理、性能及关键参数的确定方法。在林区进行的小范围试验表明效果很好。该装置已获得了国家专利。     

绿僵菌和白僵菌对台湾乳白蚁致病力的研究

实验通过配制不同浓度的绿僵菌和白僵菌菌液,采用喂食和涂抹两种不同的感染方式,分别感染台湾乳白蚁群体,研究绿僵菌和白僵菌对台湾乳白蚁的致病力.初步结果表明:绿僵菌和白僵菌对台湾乳白蚁具有一定的致病力,但短时间内的致病力较低,可能是台湾乳白蚁群体内存在着控制真菌生长和扩散的社会行为,所以这两种病原性真菌作为潜在的白蚁生物防治剂值得商榷.     

白僵菌871菌株毒理及其防治茶丽纹象甲

研究白僵菌 871菌株对茶丽纹象甲的致病机理 ,幼虫是孢子萌发后直接侵染体壁、气门、节间膜等 ;成虫则是大量孢子通过吞食进入体内萌发侵染虫体 ,少量萌发孢子通过体壁、气门等侵染虫体 ,侵染发病后形成白色僵尸。它对茶丽纹象甲幼虫、成虫均有极强的致病力 ,室内试验处理罹病率达 90 %以上 ,其侵染速率与温度呈正相关 ,即温度高 ,侵染速率快。用该菌防治茶丽纹象甲幼虫、蛹、成虫 ,面积 2 0 0 0 ha,防效达 6 8.2 % -96 .3% ,平均防效 81.8%。     

球孢白僵菌工程菌株构建及其环境安全性分析

以球孢白僵菌（Beauveriabassiana）Bb202作为出发菌株,同时引入外源毒力基因,即北非蝎（Androctonusaustralis）昆虫特异性神经毒素多肽基因AalT（GI：69545）,构建高毒力的工程菌株Bb202T-7,并用SPSS软件统计分析,结果显示,Bb202T-7对松墨天牛（Monochamusalternatus）的杀虫效率提高了11．11％。研究目的是为生物防治提供性能良好的出发茵株,为高效杀虫剂的研制提供基础资源,克服真菌杀虫剂击倒昆虫所需时间长,对环境条件要求高等缺点,加速真菌杀虫剂的产业化步伐。同时对基因工程重组菌株的安全性问题进行分析,并提出解决方案。     

球孢白僵菌对烟蚜致病力研究

通过球孢白僵菌兑成孢子悬浊液感染烟蚜的方法检测球孢白僵菌对烟蚜的致病力和防治效果.室内试验时所供测试的七个菌株均对烟蚜具有毒性,其中菌株C j4、Ly4、Sc145的感染致死力均达到100%,菌株Sc145在第6 d感染率就达到100%,表现最为突出;室外试验在第6 d时所有菌株对烟蚜的防治效果都大于85%,最高为菌株Sc145、C j4,达到93.4%和93.3%.从中有球孢白僵菌对烟蚜有较强的感染致死力,其中测试菌株Sc145、C j4室内感染致死力和室外防治烟蚜效果最好.     

外界条件对球孢白僵菌几丁质酶的影响

本文研究了球孢白僵菌(Beauveria bassiana)的培养条件——温度、初始pH值、接种量、培养时间等对产几丁质酶的影响;探讨了几丁质酶活性与几丁质浓度、粒子大小、酶解温度、pH值的关系;从而获得了高活性几丁质酶的培养条件及生物转化几丁质废物的适宜环境.     

Mechanism of Action of Endophytic Fungi Hypocrea lixii and Beauveria bassiana in Phaseolus vulgaris as Biopesticides against Pea Leafminer and Fall Armyworm

Endophytic fungal isolates Hypocrea lixii F3ST1 and Beauveria bassiana G1LU3 were evaluated for their potential to endophytically colonize and induce active compounds in Phaseolus vulgaris, as a defense mechanism against pea leafminer (Liriomyza huidobrensis) and fall armyworm (Spodoptera frugiperda). Endophytic colonization was achieved through seed inoculation with the volatile emissions from P. vulgaris plants being analyzed using GC-MS. The crude extracts of P. vulgaris obtained using methanol and dichloromethane were assayed against leafminer and fall armyworm larvae using leaf dipping and topical application, respectively. The two isolates successfully colonized the entire host plant (roots, stems, and leaves) with significant variation (p < 0.001) between fungal isolates and the controls. The results showed qualitative differences in the volatile profiles between the control plants, endophytically colonized and insect-damaged plants attributed to fungal inoculation and leafminer damage. The crude methanol extracts significantly reduced the percentage pupation of 2nd instar leafminer larvae (p < 0.001) and adult-flies emergence (p < 0.05). The survival of the 1st instar fall armyworm larvae was also significantly reduced (p < 0.001) compared to the controls. This study demonstrated the high potential of endophytic fungi H. lixii and B. bassiana in inducing mainly specific defense compounds in the common bean P. vulgaris that can be used against pea leafminer and fall armyworm.