豆野螟在人工饲料上的发育和繁殖情况

以天然寄主豇豆的花和荚作为对照,考查一种改进后的人工饲料对豆野螟Maruca testulalis Geyer生长发育的影响。结果表明:人工饲料饲养的豆野螟幼虫总历期与对照组之间不存在显著差异,说明人工饲料可以满足豆野螟幼虫正常生长发育的需要。取食工人饲料的豆野螟1龄和2龄幼虫存活率低于对照组,3龄后的存活率则高于对照组。人工饲料饲养豆野螟1代和3代羽化率分别为96.72%和96.47%,对照组的羽化率为94.41%,二者之间存在显著差异。不同产卵条件对产卵量没有显著影响,但豇豆叶上卵的历期比滤纸和绒布短,且孵化率也较后两者高。     

高原蔗区甘蔗螟虫种群结构及螟害枯心苗发生规律

【目的】明确不同种植制度下甘蔗螟虫种群结构及螟害枯心苗发生规律特征,以期为指导预警监测和制定防控措施奠定基础。【方法】应用自然种群接虫方法,定期调查不同植期、不同品种螟害枯心苗,对螟虫种群结构、枯心苗苗龄及螟虫幼虫龄期特征、枯心苗动态等指标进行分析。【结果】水田蔗区以大螟Sesamia inferens Walker为主,伴有少量黄螟Argyroploce schistaceana Snellen,旱地蔗区以大螟为主,伴有二点螟Chilo infuscatellus Snellen和极少量黄螟。甘蔗低苗龄时,枯心苗中2龄幼虫数量最多,随着苗龄的增加,枯心苗中3龄、4龄等幼虫逐渐增多。其中,大螟为害枯心苗集中在6~8叶,枯心苗中幼虫以3龄和4龄为多;黄螟为害枯心苗集中在4~8叶,枯心苗中幼虫以3龄和5龄为多;二点螟为害枯心苗集中在5~8叶,枯心苗中幼虫以3龄和4龄为多。不论水田旱地,甘蔗苗期螟害枯心苗均会出现波动,但水田蔗区较旱地蔗区波动小。【结论】不同种植制度螟虫种群结构不同,不同螟虫和甘蔗品种影响枯心苗特征及其发生动态。     

豇豆荚螟人工饲料的初步研究

本文以绿豆粉、长豇豆粉、酵母粉、多维葡萄糖、琼脂、山梨酸和甲醛为原料配制了6种人工饲料饲养豇豆荚螟Maruca testulalis Geyer,以改进其人工饲料的饲养效果。结果表明：以绿豆粉和长豇豆粉为主要原料配制的配方5和配方6饲养效果较好。尤其是配方6,豇豆荚螟的幼虫存活率和历期、蛹重和化蛹率、成虫羽化率与天然饲料饲养的豇豆荚螟相比没有差异,表明该人工饲料可用于室内人工饲养豇豆荚螟。     

中红侧沟茧蜂对不同龄期棉铃虫幼虫及其为害棉株的趋性反应

研究中红侧沟茧蜂Microplitis mediator Haliday对棉铃虫Helicoverpa armigera Hübner幼虫及其为害棉株的趋性行为, 可为高效应用中红侧沟茧蜂控制棉铃虫提供理论依据。本研究在实验室内以中红侧沟茧蜂雌蜂、1~5龄棉铃虫幼虫及其为害棉花植株（去虫或未去虫）为试验材料, 采用“Y”型昆虫嗅觉仪测定了中红侧沟茧蜂雌蜂对1~5龄棉铃虫幼虫及其为害棉株的趋性行为反应。结果表明: 中红侧沟茧蜂对3龄、4龄和5龄棉铃虫幼虫均没有明显的趋向行为反应, 1龄和2龄棉铃虫幼虫对中红侧沟茧蜂有显著的引诱作用。此外, 1~5龄棉铃虫幼虫为害后去虫棉株与健康棉株均对中红侧沟茧蜂有吸引作用。在未去虫的处理中, 虫害诱导棉株比健康植株更能吸引中红侧沟茧蜂, 与健康植株差异显著, 而且不同龄期棉铃虫幼虫为害处理间差异较大, 对中红侧沟茧蜂引诱作用的相对顺序为: 5龄为害植株>2龄和4龄为害植株>1龄和3龄为害植株 (2龄和4龄为害处理间差异不显著; 1龄和3龄为害处理间差异不显著)。本研究结果可为中红侧沟茧蜂在生物防治上的应用提供一定的理论指导和实践依据。     

基于外部形态特征量化分析判别菱角水螟幼虫龄期

【目的】本实验拟为田间准确快速判别菱角水螟Parapoynx crisonalis(Walker)幼虫龄期提供一种新方法,以便监测其发生规律、预测其发生时间。【方法】本研究通过对幼虫头壳宽、复眼距、体宽和体长4项外部形态指标的测量,运用Crosby生长法则和线性回归分析方法,结合各项指标的频次分布进行分析。【结果】各龄幼虫头壳宽平均值的变异系数和Crosby指数最小,为判别幼虫龄期的最佳分龄指标,幼虫期共分为5龄,1~5龄的头壳宽分别为(0.2493±0.0053)、(0.3454±0.0018)、(0.5079±0.0031)、(0.7419±0.0190)和(1.1287±0.0369)mm,其与龄期数呈线性关系。通过实验室饲养观察菱角水螟幼虫蜕皮次数验证该虫幼虫期分为5个龄期。【结论】头壳宽为判定菱角水螟幼虫龄期的最佳指标,复眼距次之。     

豇豆荚螟的生物学特性与防治技术研究

本文较全面地报道了豇豆荚螟在湖南长沙、湘潭地区的生物学特征、发生动态与环境因子的关系 ,提出了以化学防治为主的豇豆荚螟综合防治技术。豇豆荚螟在上述两地区 1年能发生 6～ 7代 ;1～ 6代各代历期依次为 33.5,2 3,2 1,2 8,34.5和 4 4天。寄主生育期可影响该虫的发生量 ,采用“治花不治角 ,打顶不打底”的施药方法 ,能提高药剂防治效果 ,降低农药残留量。在防治试验用的 12种药剂中 ,2 5%乙酰甲胺磷乳油、2 .5%敌杀死乳油、生长调节剂 5%定虫隆 (抑太保 )、细菌性杀虫剂 Bt乳剂和 HD- 1的防治效果在 80 %以上 ;灭幼脲 2号、甲氰菊酯、氯氰菊酯和辛硫磷 ,防治效果在 70 %～ 80 %之间 ;而敌百虫、乐果、敌敌畏的防治效果不达 70 %     

黄野螟群体大小对幼虫个体生存和发育的影响

幼虫聚集取食是一些鳞翅目昆虫提高幼虫生长和存活的手段。通过对聚集取食的黄野螟Heortia vitessoides Moore幼虫在室内条件下进行饲养,探究黄野螟幼虫的群体数量大小（分别为30、60、90头幼虫）对幼虫体长、发育速度、达末龄（5龄）时的存活率的影响。分析发现在排除天敌捕食和食物缺乏的前提下,从3龄开始,大群体（90头）的体长显著大于小群体（30头）,大群体的幼虫发育速度显著快于小群体,大群体对幼虫前4个龄期时的成活率没有显著提高,尽管大群体的存活率在均值上高于小群体,但是幼虫总体存活率在不同群体中差异不显著。黄野螟幼虫的聚集取食对幼虫的生长的促进作用明显,显著促进了幼虫的生长,加快了幼虫的发育。     

褐边绿刺蛾的取食行为和取食量

观察褐边绿刺蛾Parasa consocia Walker2个世代幼虫取食杨树叶片的习性。结果表明,第1代幼虫7龄,幼虫期平均取食量167.7cm2/头,取食持续时间26d;第2代幼虫8龄,幼虫期平均取食量170.5cm2/头,取食持续时间27d。2个世代末龄幼虫取食量最大,占整个取食量的80%左右,4~5龄幼虫是防治的关键龄期。     

溴氰菊酯亚致死浓度对烟草粉螟生物学特性的影响

为探讨溴氰菊酯对烟草粉螟的亚致死效应,本文采用烟叶浸渍法以溴氰菊酯亚致死浓度(LC 10和LC 25)胁迫烟草粉螟3龄幼虫,并通过年龄-龄期两性生命表的方法探究溴氰菊酯胁迫对烟草粉螟发育和繁殖的影响。结果显示:与对照相比,溴氰菊酯LC 10、LC 25处理F 0代的平均单雌产卵量显著下降;LC 25处理F 0代的产卵前期及总产卵前期明显长于对照;LC 25处理与LC 10处理和对照间,F 0代雌、雄虫寿命均差异显著;LC 10处理和LC 25处理F 1代与对照存活率明显下降,F 1代各处理间的卵、1龄幼虫、3龄幼虫、5龄幼虫、7龄幼虫和蛹的发育历期无显著差异;但LC 25处理组2龄、4龄、6龄幼虫历期比对照延长了且差异显著;LC 25处理组的成虫前期比对照组延长了且差异显著。同时LC 25处理的雌、雄虫寿命最短,但3个处理间差异不显著。研究表明,亚致死浓度的溴氰菊酯能够抑制烟草粉螟的生长发育和繁殖,以上研究结果可为田间用药控制烟草粉螟提供理论参考。     

豆野螟的生物学特性及其防治

豆野螟Maruea testulalisGeyer(1832)是我国豆类蔬菜,特别是长豇豆Vigna sesguipedalis的主要害虫。在杭州,一年发生七代,以预蛹越冬。以1—3代为害为主。一龄幼虫头宽0.197毫米,Dyar常数为1.653。随虫龄增加,取食场所从花器转向豆荚。产卵前期为3—4天,羽化后6—8天卵量最集中。幼虫、蛹发育历期与日平均温度间的对数回归方程为Y₁=3.5825—1.7766x,Y_p=3.8118-2.0800x。卵期2—4天。田间为害以6—8月为主;灯下威虫有7月和9—10月两个高峰。有分距姬蜂Cremastus sp.和稻苞虫寄蝇Pseudoperiehaeta insidiosa二种天敌。应用80%敌敌畏800倍等农药,在百花虫数达40头上下、二龄幼虫约占50%时,兼喷植株、落地花,能达到降低花、荚被害率,提高鲜荚产量、品质和降低成本的效果。     

壳聚糖酶的克隆表达与壳寡糖的制备分析

目的:克隆壳聚糖酶基因于大肠杆菌中实现高表达,制备壳寡糖。方法:以枯草芽孢杆菌总DNA为模板扩增壳聚糖酶基因(CSN),克隆至载体pET23a(+)上,转化菌株BL21(DE3)。重组子经0.5 mmol/L IPTG诱导后,SDS-PAGE和质谱检测与鉴定重组酶。酶纯化后水解壳聚糖,薄层色谱分析其水解产物。结果:质谱证明壳聚糖酶(31.5kDa)成功表达,表达量占菌体总蛋白的45%左右。纯化后重组酶浓度为900 mg/L,纯度95%、回收率85%,酶活力为10 000 U/mg。壳聚糖降解产物为壳二糖至壳四糖。结论:原核表达载体pET23a(+)-CSN构建正确,壳聚糖酶表达量与活性高,适用于水解壳聚糖制备壳寡糖。     

国内外蝗害治理技术现状与展望

本文首先概述了国内外蝗虫发生与为害的态势,总结了现阶段我国蝗虫发生与为害的主要特点:即农田飞蝗暴发频繁而且严重,草原土蝗的发生时常造成严重的经济损失,而且侵入城市干扰市民生活,我国与周边国家之间蝗虫过境迁移频繁,使用化学农药污染环境和农产品;分析了国内外蝗虫防治对策与技术的发展现状,重点介绍了应急防治和可持续治理对策、...     

Kinetics and thermodynamics of peroxidase- and laccase-catalyzed oxidation of N-substituted phenothiazines and phenoxazines

N -substituted phenothiazines (PTs) and phenoxazines (POs) catalyzed by fungal Coprinus cinereus peroxidase and Polyporus pinsitus laccase were investigated at pH 4–10. In the case of peroxidase, an apparent bimolecular rate constant (expressed as k _cat/K _m) varied from 1 ×10⁷M⁻¹s⁻¹to 2.6×10⁸M⁻¹s⁻¹ at pH 7.0. The constants for PO oxidation were higher in comparison to PT. pH dependence revealed two or three ionizable groups with pK _a values of 4.9–5.7 and 7.7–9.7 that significantly affected the activity of peroxidase. Single-turnover experiments showed that the limiting step of PT oxidation was reduction of compound II and second-order rate constants were obtained which were consistent with the constants at steady-state conditions. Laccase-catalyzed PT and PO oxidation rates were lower; apparent bimolecular rate constants varied from 1.8×10⁵M⁻¹s⁻¹ to 2.0×10⁷M⁻¹s⁻¹ at pH 5.3. PO constants were higher in comparison to PT, as was the case with peroxidase. The dependence of the apparent bimolecular constants of compound II or copper type 1 reduction, in the case of peroxidase or laccase, respectively, was analyzed in the framework of the Marcus outer-sphere electron-transfer theory. Peroxidase-catalyzed reactions with PT, as well as PO, fitted the same hyperbolic dependence with a maximal oxidation rate of 1.6×10⁸M⁻¹s⁻¹ and a reorganization energy of 0.30 eV. The respective parameters for laccase were 5.0×10⁷M⁻¹s⁻¹ and 0.29 eV. Received: 20 September 1999 / Accepted: 24 February 2000     

Coiled-coil nanomechanics and uncoiling and unfolding of the superhelix and alpha-helices of myosin

The nanomechanical properties of the coiled-coils of myosin are fundamentally important in understanding muscle assembly and contraction. Force spectra of single molecules of double-headed myosin, single-headed myosin, and coiled-coil tail fragments were acquired with an atomic force microscope and displayed characteristic triphasic force-distance responses to stretch: a rise phase (R) and a plateau phase (P) and an exponential phase (E). The R and P phases arise mainly from the stretching of the coiled-coils, with the hinge region being the main contributor to the rise phase at low force. Only the E phase was analyzable by the worm-like chain model of polymer elasticity. Restrained molecular mechanics simulations on an existing x-ray structure of scallop S2 yielded force spectra with either two or three phases, depending on the mode of stretch. It revealed that coiled-coil chains separate completely near the end of the P phase and the stretching of the unfolded chains gives rise to the E phase. Extensive conformational searching yielded a P phase force near 40 pN that agreed well with the experimental value. We suggest that the flexible and elastic S2 region, particularly the hinge region, may undergo force-induced unfolding and extend reversibly during actomyosin powerstroke.     

白术同源四倍体的诱导和鉴定及其与二倍体过氧化物酶的比较

以白术（Atractylodes macrooephala Koidz.）二倍体组培苗为材料,对其四倍体诱导方法进行研究,共获得45个白术同源四倍体株系,为优良株系的选育提供了材料。此外,还分析比较了其中8个白术四倍体株系与二倍体的过氧化物酶同工酶（POD）的酶谱差异,发现四倍体各株系过氧化物酶同工酶谱比二倍体的均多了Rf0.310的谱带,且总过氧化物酶比活力也发生了很大改变,对探讨白术四倍体优良株系的生理生化机理具有一定的参考价值。     

放牧对牧草光合作用、呼吸作用和氮、碳吸收与转运的影响

研究放牧对草地植物生理活动的影响,对于揭示草地放牧演替的生理机制有重要意义.大量研究表明,家畜放牧对牧草光合作用、呼吸作用以及C和N吸收与转运的影响,可以分为生理伤害和生理恢复2个阶段.放牧通过改变草地冠层结构影响牧草光合作用,净光合作用速率短期内迅速下降,随着叶面积指数增加又逐渐上升,呼吸作用有相似的变化趋势.牧草放牧后再生长所需的C和N最初主要来自根系和留茬中的贮藏物质,此后随着牧草生长恢复逐渐由同化作用供给,C代谢与土壤N水平负相关.放牧后牧草生理活动变化与牧草遗传特性、种间竞争、家畜放牧特征、非生物环境等因素密切相关.     

Synthesis of hapten and conjugates of coumestrol and development of immunoassay

3-O-Carboxymethylcoumestrol was prepared as the hapten for immunoassay by a partial alkylation of coumestrol with ethyl chloroacetate in acetone alkalized with potassium carbonate. 3-O-Ethoxycarbonylmethylcoumestrol was separated by column chromatography and finally was hydrolyzed with formic acid. 1H and 13C NMR data (APT, COSY, HMQC, and HMBC) revealed that the reaction was regioselective, as 3-O-ethoxycarboxymethylcoumestrol was the only monosubstituted derivative. The hapten was then conjugated to bovine serum albumin and used for immunization of rabbits. A radioimmunoassay (RIA) system was established based on the polyclonal antiserum and a 125I-labeled hapten-tyrosine methyl ester conjugate as the radioligand. Parameters of the RIA: sensitivity: 12 pg per tube, 50% intercept: 140 pg per tube, working range: 20-4000 pg per tube. The cross-reactivity of a panel isoflavonoid and lignan phytoestrogens was either negligible (e.g. formononetin 0.07%; biochanin A 0.06%) or not detectable at all. The major immunoreactive peak in HPLC fractions from an alfalfa extract had the same retention time as coumestrol standard and represented 94.8% of the signal. The remaining 5.2% of immunoreactivity was distributed between five minor peaks. We conclude that after the validation for particular matrices, the method will be a useful tool for analysis of coumestrol, especially in low volume and low concentration samples.