Synergism of insecticides provides evidence of metabolic mechanisms of resistance in the obliquebanded leafroller Choristoneura rosaceana (Lepidoptera: Tortricidae)

The interactions between six insecticides (indoxacarb, cypermethrin, chlorpyrifos, azinphosmethyl, tebufenozide and chlorfenapyr) and three potential synergists, (piperonyl butoxide (PBO), S,S,S-tributyl phosphorotrithioate (DEF) and diethyl maleate (DEM)) were studied by dietary exposure in a multi-resistant and a susceptible strain of the obliquebanded leafroller, Choristoneura rosaceana (Harris). The synergists did not produce appreciable synergism with most of the insecticides in the susceptible strain. Except for tebufenozide, PBO synergized all the insecticides to varying degrees in the resistant strain. A very high level of synergism by PBO was found with indoxacarb, which reduced the resistance level from 705- to 20-fold when PBO was administered alone and to around 10-fold when used in combination with DEF. DEF also synergized indoxacarb, cypermethrin, chlorpyrifos, azinphosmethyl and tebufenozide in the resistant strain. DEM produced synergism of indoxacarb, chlorpyrifos, azinphos-methyl and chlorfenapyr in the resistant strain. DEM was highly synergistic to cypermethrin, and to some extent to tebufenozide in both the susceptible and resistant strains equally, implying that detoxification by glutathione S-transferases was not a mechanism of resistance for these insecticides. The high level of synergism seen with DEM in the case of cypermethrin may be due to an increase in oxidative stress resulting from the removal of the antioxidant, glutathione. These studies indicate that enhanced detoxification, often mediated by cytochrome P-450 monooxygenases, but with probable esterase and glutathione S-transferase contributions in some cases, is the major mechanism imparting resistance to different insecticides in C. rosaceana.     

不同生育期和不同品种苜蓿的果胶含量及与其他营养素的相互关系

采用4×5两因子设计,研究了不同生育期(营养期、孕蕾期、开花初期和开花盛期)和不同品种(陇东、新疆大叶、L 173、Derby和Super 7)苜蓿中的果胶含量及与干物质、有机物质、粗蛋白、粗纤维、中性洗涤纤维、酸性洗涤纤维、酸性洗涤木质素、钙和磷等的相互关系。结果表明,1)随着生育期的推移,苜蓿中果胶的含量逐渐降低,营养期、孕蕾期、开花初期和开花盛期5个品种的平均(干物质基础)果胶含量分别为11.2%,9.23%,9.07%和8.28%;2)苜蓿中果胶含量与其他各养分含量间存在显著相关关系,其中与粗蛋白质(r=0.952,P=0.048)呈显著正相关关系;与有机物质(r=-0.961,P=0.039)呈显著负相关关系;3)不同品种苜蓿间果胶及其他各养分含量(4个生育期平均,干物质基础,下同)存在显著差异,Super 7的果胶含量显著高于L 173(P<0.05);陇东苜蓿的粗蛋白含量显著高于新疆大叶、Super 7和L 173(P<0.05);Derby的粗纤维含量显著高于Super 7(P<0.01)、L 173(P<0.05)和新疆大叶(P<0.05),中性洗涤纤维含量显著高于Super 7(P<0.05);而Super 7的酸性洗涤纤维含量显著低于其他4个品种(P<0.05);Super 7的钙含量高于其他4个品种(P<0.05);品种间磷含量无显著差异(P>0.05)。     

不同浓度吡虫啉对禾谷缢管蚜酯酶的影响

采用生物化学方法研究不同剂量吡虫啉对禾谷缢管蚜酯酶活性和酶动力学参数的影响.结果表明,不同浓度吡虫啉处理禾谷缢管蚜后,可极显著诱导禾谷缢管蚜蛋白含量增加和酯酶活力增强,且不同处理组间蛋白含量差异显著,但不同剂量吡虫啉处理并未对禾谷缢管蚜酯酶动力学参数产生明显影响.不同浓度吡虫啉处理禾谷缢管蚜后,并未改变其酯酶的性质,但酯酶的表达量显著增加.     

诱导剂对番木瓜环斑病毒病的防治效果

为了探讨水杨酸、茉莉酸甲酯和壳聚糖对番木瓜环斑病毒病的病情指数和防治效果的影响,在番木瓜上喷施不同浓度的诱导剂,然后在叶腋处接种番木瓜环斑病毒,观察和记录番木瓜的病情指数,计算其防治效果.结果表明,诱导剂提高了番木瓜对环斑病毒病的抗性,其中水杨酸的效果优于茉莉酸甲酯和壳聚糖.水杨酸、茉莉酸甲酯和壳聚糖的最佳施用浓度分别为50 mg/L、0.05 mmol/L和1％,最佳防治效果则分别为77.19％、53.11％和22.95％.水杨酸、茉莉酸甲酯、壳聚糖与对照之间的防治效果差异极显著,3种诱导剂在最佳浓度下防治效果差异极显著.50 mg/L水杨酸对番木瓜环斑病毒病防治效果最佳,在生产上施用具有一定的经济效益.     

茉莉酸甲酯诱导柿树挥发物对红点唇瓢虫吸引力的持续效应

为明确茉莉酸甲酯(MeJA)诱导柿树(Diospyros kaki Linn.f.)挥发物成分的变化对蚧虫的天敌昆虫红点唇瓢虫(Chilocorus kuwanae Silvestri)吸引力的持续效应,应用3种剂量(20、100μL和200μL)的MeJA处理柿树,通过"Y"型嗅觉仪测试瓢虫的行为反应,并采用顶空收集和气质联用(GC/MS)分析挥发物的组成和相对含量。结果表明,MeJA可以诱导树体挥发物成分发生改变,对瓢虫产生吸引力,其持续效应可达1d以上。而不同剂量的处理组之间存在差异,高剂量组中萜烯类物质含量最多,在处理后3h瓢虫的趋性最强,相应的α-蒎烯含量高达34.05%。处理3～5d后吸引力显著下降,α-蒎烯等化合物的含量也逐渐减少。因此,茉莉酸甲酯的连续应用可以招引更多的瓢虫来控制蚧虫。     

白蚁肠道可培养菌群及其功能初探

白蚁是一种危害严重的昆虫,其以破坏木质而家喻户晓.文献表明,白蚁对木质强大的消化能力很大程度上取决于其肠道微生物的影响.为了探究白蚁肠道微生物的类群,本试验以黑翅土白蚁为材料,分离纯化获得其肠道主要可培养微生物的纯培养112种,其中喜氧菌35种,厌氧菌77种;在分离出的微生物类群中,通过刚果红法初步筛选出12种喜氧菌菌株可能具有纤维素酶活性,其最大透明圈达到4.0㎝×4.0㎝;进一步检测这些菌株的纤维素酶活性发现,12株菌均具有羧甲基纤维素钠盐(CMC-NA)酶活性和滤纸酶活性,但是大部分菌株羧甲基纤维素酶活性较弱,而一些菌株如 NBY14滤纸酶活较高,可达到16.188u/mL.试验结果可为黑翅土白蚁防治提供依据,亦可为纤维素酶的开发利用奠定基础.     

脂肪酶和酯酶指纹分析在嗜酸耐热菌快速鉴定中的应用

【目的】采用反相高效液相色谱建立嗜酸耐热菌的脂肪酶和酯酶指纹图谱,为建立基于脂肪酶和酯酶指纹分析的嗜酸耐热菌快速鉴定方法提供参考。【方法】将5个脂肪酶和酯酶底物直接与嗜酸耐热菌反应,通过反相高效液相色谱检测得到了9株嗜酸耐热菌的脂肪酶和酯酶指纹色谱图,并对色谱数据进行系统聚类分析。【结果】所得脂肪酶和酯酶指纹图谱能将脂环酸芽孢杆菌和芽孢杆菌明显分为2个类群,且同一属的2个不同种的细菌也能得到正确归类。【结论】脂肪酶和酯酶指纹分析能够用于嗜酸耐热菌的快速鉴别,且简便快速、重现性好、经济成本低,具有广阔的应用前景。     

六甲基六元瓜环与紫精衍生物作用体系及其除草活性研究

以紫精衍生物为研究对象,利用核磁共振技术、紫外吸收光谱和循环伏安法等方法,发现六甲基六元瓜环包结了紫精衍生物的烷基部分,形成2∶1比例的哑铃型包结配合物.结果表明,随着紫精衍生物烷基链的增长,紫精衍生物对杂草的除草活性依次减弱,且六甲基六元瓜环可增强紫精衍生物的除草活性.     

柿果成熟过程中可溶性果胶和单宁含量的变化

为了解从柿中提取果胶和单宁的最适宜时期,本试验以磨盘柿和平核无为材料,采用咔唑比色法和folin-ciocaileu法,分析了不同取样时期2个柿品种果皮和果肉可溶性果胶和单宁含量变化。随着果实的成熟,柿果中可溶性果胶的含量呈现相似的变化规律:都是逐渐升高,且果肉高于果皮,平核无高于磨盘柿。各个取样时期,2个品种的柿中可溶性单宁也呈现相似的变化规律:逐渐下降,且果肉高于果皮,平核无高于磨盘柿。同时分析了不同时期榨汁的果汁随存放时间的延长,可溶性果胶和单宁变化。随着榨汁时间的不同,可溶性果胶的含量分别在果汁存放0、10和30d达到最大值,可溶性单宁的含量在果汁存放的20到30d含量最大;且平核无果汁可溶性单宁和果胶的含量高于磨盘柿。平核无比磨盘柿,果肉比果皮是更适宜作为提取可溶性果胶和单宁的材料。     

Bacteria inhabiting artificially inoculated xylem of Picea abies

Bacteria inhabiting the xylem of Norway spruce (Picea abies (L.) H. Karsten) were investigated. The trees had been wounded and artificially inoculated with fungi and bacteria obtained from wounds of naturally infected spruce. One and five growing seasons after inoculation the Gram‐negative bacterial population present in the stem of inoculated trees were analysed.

The Gram‐negative bacteria isolated from the trees were identified on the basis of morphological, biochemical and physiological tests and whole‐cell fatty acid composition. The predominant strains were Enterobacteriaceae fermenter strains (E. agglomerans or E. sakazakii), fluorescent and yellow pigmented Pseudomonas, Acinetobacter and Moraxella spp. All Gram‐positive bacteria were Bacillus species.

The Gram‐negative bacteria of Norway spruce differed from the Gram‐positive species in possessing stronger lipolytic activity and in their ability to utilize pine resins for growth. Gram‐positive bacteria were generally able to utilise cellulose and hemicellulose, whereas among the Gram‐negative bacteria only one xylanolytic (yellow Pseudomonas) strain was found.