杠柳杀虫活性成分的分离

采用柱层析分离、高效液相色谱切分和生物活性追踪法,从杠柳 Periploca sepium 根皮甲醇提取物中分离出2个具有杀虫活性的化合物(G1和G2),经鉴定其分别为已知物杠柳新苷D和F。生物活性测定结果表明,化合物G1和G2 对3龄粘虫 Mythimna separata 48 h的胃毒致死中浓度(LC50)分别为0.39和0.34 mg/mL, 对小菜蛾 Plutella xyllostella 48 h的胃毒LC50值分别为1.21和1.39 mg/mL。     

灰葡萄孢菌激活蛋白PEBC2的生物功能

通过沸水浴、离心、阴离子交换层析等方法,从灰葡萄孢菌Botrytis cinerea BC-4-2-2-1菌丝体中分离纯化出一种激活蛋白,命名为PEBC2,经SDS-PAGE银染显示呈单一条带,相对分子量约为14kD。该激活蛋白能显著提高小麦种子的发芽率,促进小麦幼苗生长,增强小麦的抗旱性和番茄对灰霉病的抗性。经激活蛋白处理后小麦发芽率从75.00%提高到98.33%,处理7、9、11天时株高分别比对照增加了17.07%、23.05% 和17.19%,幼苗抗旱综合系数从36.53提高到57.45;该激活蛋白对番茄灰霉病的诱抗效果达60.09%。     

Toxicity and sublethal effects of an insecticidal soap on Aphidius colemani (Hymenoptera: Braconidae)

BACKGROUND: The effects of an insecticidal soap on the survival, fitness and behaviour of an aphid parasitoid wasp, Aphidius colemani (Viereck), were studied in the laboratory. The LC(50) (soap concentration causing 50% mortality 24 h after treatment) was determined. The survival of parasitoid larvae (% adult emergence), fitness (tibia length of adults) and number of eggs produced per female parasitoid that survived in third- and fourth-instar aphids treated with insecticidal soap LC(50) were also assessed. The LC(50) for third- and fourth-instar aphids was determined to be 3.25 g L(-1). Acceptance by female parasitoids of aphids that survived their LC(50) was also tested. RESULTS: The soap concentration causing 100% mortality in adult wasps 24 h after treatment was 17.5 g L(-1). The LC(50) was 2.75 g L(-1). Soap did not have any effect on the survival of parasitoid immatures or on the fitness or number of eggs produced per female parasitoid. Wasps that were in contact with treated aphids did not oviposit as much in them as in untreated aphids, indicating that female parasitoids detected aphids treated with insecticidal soap. CONCLUSION: These data suggest that aphid parasitoids released following treatment with insecticidal soap are likely to accept a lower proportion of the surviving aphids. Biological control programmes could be ameliorated by soap applications if the latter were made 1 day before the release of wasps in the greenhouse.     

蔬菜中灭蝇胺残留的强阳离子交换固相萃取柱净化-液相色谱分析

建立了简单、快速测定蔬菜中灭蝇胺残留量的方法。蔬菜样品经乙酸胺-乙腈(1∶ 4,体积比)混合溶液提取,强阳离子交换固相萃取(SCX-SPE)柱净化后,采用高效液相色谱仪在波长215 nm处测定,所用色谱柱为Agilent NH2,流动相为乙腈-水溶液(97∶ 3,体积比),以1.0 mL/min的流速等梯度洗脱。结果表明,在浓度为0.02~2 mg/L范围内,线性相关系数为0.999 9。灭蝇 胺的添加浓度在0.05~0.4 mg/kg范围内,平均回收率为83.4%~104%,相对标准偏差为1.7%~8. 4%,均在农药残留测定所允许的范围内。该方法的最低检出限(LOD)为0.02 mg/kg,最低检测浓度(LOQ)为0.05 mg/kg。     

苏云金芽孢杆菌cry9Aa基因的克隆、表达及活性分析

为了解决目前广泛使用的cry1A类基因的抗性问题,获得对鳞翅目害虫高效杀虫基因,从菌株SC5D2和T03C001中鉴定并克隆到了2个新型cry9Aa基因,被Bt国际命名委员会分别正式命名为cry9Aa3和cry9Aa4,并进一步对其编码的蛋白进行活性测定。结果显示,2个基因对小菜蛾、玉米螟均具有较高的杀虫活性,其中对小菜蛾的LC50分别为1.83μg/mL和1.90μg/mL,对玉米螟的LC50分别为6.93μg/mL和1.06μg/mL。同时,两种Cry9Aa蛋白对Cry1Ac抗性小菜蛾都具有较高的杀虫活性,LC50分别为1.74μg/mL和1.39μg/mL,与敏感小菜蛾杀虫活性测定数据相当,表明Cry9Aa与Cry1Ac没有交互抗性。     

孔石莼(Ulva pertusa)中一种抗TMV活性蛋白的纯化及其特性

 采用硫酸铵盐析和阳离子交换柱层析(CM-Sepharose Fast Flow),从孔石莼(Ulva pertusa Kjellm)藻体中分离纯化得到1个蛋白,命名为UPCM40。经SDS-PAGE确定其分子量约为36kD,Native-PAGE可知其为单一组分;该蛋白不含糖;其全波长扫描结果显示,该蛋白在190~220nm和250~300nm处有特征吸收峰,在250~300nm范围中的最大吸收峰在270~275nm处。经测定发现该蛋白具较好的抗烟草花叶病毒(Tobacco mosaic virus,TMV)的活性,当蛋白质浓度为50μg/mL时,对TMV的抑制效果为:在枯斑寄主心叶烟上的侵染抑制率达85.6%,在苋色藜上为90.2%。测定该蛋白对6种供试真菌的抑制效果发现,对镰刀菌(Fusarium oxysporum f.sp.cucumerinum)、立枯丝核菌(Rhizoctonia solani)和香蕉炭疽菌(Gloeosporium musarum)均有一定程度的抑菌作用,但抑制活性很低。     

Isolation and identification of the major insecticidal compound of poleo (Lippia stoechadifolia)

The major insecticidal fraction of poleo (Lippia stoechadifolia) was purified by thin-layer chromatography and repeated crystallizations. Analyses of ultraviolet, infrared, mass, and ¹³C and ¹H nuclear magnetic resonance spectra indicate that the active compound is a monoterpenoid, pulegone-1,2-epoxide.     

建兰胶孢炭疽菌ITS序列分析及其PCR快速检测

由胶孢炭疽菌Colletotrichum gloeosporioides引起的炭疽病是建兰的重要病害.为建立快速检测该病原菌的方法,以ITSl/ITS4为引物,对15个建兰胶孢炭疽菌的ITS进行PCR扩增及测序,将测定的序列与炭疽菌属其它种的ITS序列进行比对分析,设计特异性引物CFl/CR1,并通过常规和巢式PCR对建兰胶孢炭疽菌进行检测.结果显示,15个菌株中有13个菌株ITS序列与该菌的模式种序列相似性高达99％以上,而另外2个菌株相似性则为86％;供试菌株在系统发育树上聚为2个不同的分支;引物CFl/CR1通过常规PCR可从1 ng的建兰胶孢炭疽菌基因组DNA中扩增到目的条带,而利用引物ITSl/ITS4和CF1/CR1通过巢式PCR可从1 pg的基因组DNA中扩增到目的条带,即巢式PCR反应检测灵敏度较常规PCR至少高1 000倍.表明建立的巢式PCR法可从自然感病的建兰叶片组织中检测到胶孢炭疽菌.