桔小实蝇成虫对不同颜色和气味物质的趋性反应

研究了不同颜色和气味物质对桔小实蝇(Bactrocera dorsalis Hendel)取食和产卵选择以及趋向行为的影响。结果表明:桔小实蝇成虫对绿色食物具有较强的取食趋性,橙色次之,对黄色和红色的食物趋性弱,同时,雌、雄虫之间对食物颜色的选择无明显差异;在黄、绿、白3种颜色中,桔小实蝇对黄色基质的产卵趋性最强,绿色次之,对白色基质的产卵趋性最弱;嗅觉实验结果中,桔小实蝇成虫对乙酸乙酯、蔗糖、蜂蜜和酵母的气味表现明显趋性,但对红糖气味无趋性反应;而乙酸对桔小实蝇成虫有明显驱避活性;而雌虫对这些物质的嗅觉反应敏感于雄虫。     

12种杀虫剂对柑橘大实蝇选择行为的影响及击倒作用

柑橘大实蝇是柑橘上的重要害虫。本文分别利用Y型嗅觉仪和饲喂法测定了柑橘大实蝇成虫对12种杀虫剂的选择行为和击倒作用,以期筛选出田间防治柑橘大实蝇的高效农药,并为研发其诱杀剂提供理论依据。结果表明:12种杀虫剂中,吡虫啉、阿维菌素对雌成虫具有极显著的驱避作用;多杀霉素、丁硫克百威、阿维菌素、氟铃脲对雄成虫具有极显著的驱避作用;多杀霉素、毒死蜱、噻嗪酮对雌成虫具有显著的驱避作用;啶虫脒、噻虫嗪、乙酰甲胺磷、高效氯氟氰菊酯和高效氯氰菊酯对柑橘大实蝇雌雄成虫既无驱避作用也无引诱作用。同种药剂对柑橘大实蝇雌雄成虫的击倒时间无显著差异,不同药剂间对柑橘大实蝇成虫的击倒时间有显著差异,其中啶虫脒的击倒时间(KD₅₀<1 min)最短。综合考虑杀虫剂对柑橘大实蝇选择行为的影响及击倒作用,认为啶虫脒更适宜作为柑橘大实蝇诱杀剂中的杀虫剂。     

柑橘大实蝇初羽化成虫的取食选择性

【目的】探究柑橘大实蝇Bactrocera minax初羽化成虫的取食选择性。【方法】室内观察柑橘大实蝇初羽化成虫(1-7日龄)在水和蜂蜜之间、蜂蜜中添加蛋白前后、蜂蜜中添加防腐剂前后和成虫在不同生境中的蜂蜜之间以及保鲜剂在蜂蜜中添加前后的取食选择性差异。【结果】初羽化的柑橘大实蝇雌虫在2-3日龄、雄虫在3-4日龄,表现出对水的较高选择性。蛋白添加后比添加前的选择性显著降低。在不同生境的营养之间,雄虫对五倍子蜂蜜表现出显著高的选择性。另外,添加保鲜剂(山梨酸和尼泊金)后的选择性也显著降低。【结论】柑橘大实蝇羽化后1-7日日龄成虫对蜂蜜和水取食选择基本相同,蜂蜜中添加蛋白、防腐剂影响取食选择性,雄虫对不同生境中的蜂蜜更敏感。     

柑橘大实蝇成虫对板栗挥发物的行为反应

柑橘大实蝇Bactrocera minax(Enderlein)是为害柑橘类果实的毁灭性害虫。本研究采用顶空捕集法和气相色谱-质谱联用技术,对中国板栗挥发物进行了初步鉴定,并利用Y型嗅觉仪测定了1日龄和3日龄柑橘大实蝇雌、雄成虫对3种不同处理中国板栗和7种挥发性化合物的选择行为反应。结果表明中国板栗对柑橘大实蝇成虫具有极显著的诱引作用。中国板栗挥发物中含有26种化学成分,主要为一些芳香烃类、酸类、醛类、酮类、醇类、萜烯类、酯类和胺类化合物。柠檬烯、异丁醛、α-蒎烯、苯乙酸甲酯对柑橘大实蝇成虫表现出显著的诱引作用,乙偶姻和戊醛对柑橘大实蝇成虫表现出显著的驱避作用。结果进一步表明柑橘大实蝇成虫的嗅觉行为反应与化合物的浓度和成虫的日龄及性别有关,这为柑橘大实蝇成虫植物源引诱剂的开发和应用提供了一定的理论依据。     

不同生理状态的番石榴实蝇对寄主气味的行为反应

【目的】探究番石榴果实气味对番石榴实蝇Bactroceracorrecta行为的影响,为番石榴实蝇的化学生态防治提供理论依据。【方法】利用风洞观察箱观察性未成熟、性成熟未交配和交配3种不同生理状态的番石榴实蝇雌、雄成虫对单个番石榴果实气味的定向反应,对不同生理状态的雌、雄虫的飞行速度进行了分析。【结果】番石榴果实气味对不同生理状态的番石榴实蝇雌雄成虫均能产生显著的引诱效果,交配雌虫降落到气味源的数量最多,其次是性成熟未交配的雄虫,性未成熟的雄虫降落数最少。不同生理状态下的番石榴实蝇雌雄成虫逆风飞行的速度均显著高于空白对照,性成熟的番石榴实蝇雌成虫的逆风飞行速度均高于雄成虫。【结论】不同生理状态的番石榴实蝇雌雄虫对寄主番石榴气味具有不同的敏感性和选择性,已交配雌虫反应最强,其次是性成熟未交配的雄虫,性未成熟的雄虫的反应最弱。     

石斛篓象成虫对不同来源气味的行为反应

【目的】研究不同来源气味对石斛篓象Nassophasis sp.成虫嗅觉选择行为的影响,对于发展新型石斛篓象成虫防治技术具有重要意义。【方法】应用陷阱式嗅觉测定仪测试了石斛篓象成虫对同种个体气味、蛹壳气味、成虫粪便、球花石斛Dendrobium thyrsiflorum受害植株气味的嗅觉反应。【结果】雌成虫气味对雄成虫有引诱作用,对雌成虫没有引诱作用;雄虫气味对雌、雄成虫均无引诱效果。雌、雄蛹壳气味对雌、雄成虫均有显著引诱效果。两性成虫聚集时产生的粪便对雌、雄成虫均有显著引诱作用,雌虫或者雄虫单独放置时产生的粪便对雌、雄成虫均无引诱效果。被雌虫为害的球花石斛植株茎干释放的气味仅对雌虫有引诱作用, 而受雄虫为害后的茎干产生的气味仅对雄成虫有引诱作用。【结论】本研究为进一步分离、 鉴定对该虫有引诱作用的活性物质奠定了基础。     

植物果实、颜色和形状对橘小实蝇产卵选择的影响

橘小实蝇Bactrocera dorsalis(Hendel)是近几年入侵江苏南部地区,严重危害当地水果、蔬菜的重要害虫。为深入了解其在该地区果树、蔬菜上的产卵特性,进行植物果实、颜色和形状对其产卵选择影响的研究。实验室中"纸杯法"的产卵选择试验结果表明,橘小实蝇对不同水果的产卵偏好性由高到低依次为:柑橘、香蕉、芒果、枣、石榴、苹果、桃子、梨、李、葡萄、柿;对不同蔬菜的产卵偏好性由高到低依次为:丝瓜、豇豆、苦瓜、黄瓜、茄子、南瓜、青椒、番茄。对不同寄主颜色和形状的产卵选择特点为,雌虫常选择桔黄色、绿色,以及圆球形的寄主产卵,而较少选择黑色、方形的寄主产卵。从试验结果可以看出,寄主果实散发出的气味,及其颜色和形状对橘小实蝇的产卵选择有影响。     

棉铃虫成虫对两种关键花香气味的联系性学习

为了明确棉铃虫对苯乙醛和乙酸苯甲酯两种关键花香气味的联系性学习行为,在室内分别测定了不同学习训练的棉铃虫雌雄成虫对两种关键花香气味的选择偏好性反应和雄成虫的触角电位反应。偏好性测定结果表明,无花香气味接触经历的棉铃虫对苯乙醛和乙酸苯甲酯的选择频次均无显著差异,且单纯的花香气味接触经历也不能诱导棉铃虫气味偏好性的显著改变,唯有花香气味接触经历伴随蔗糖溶液进行强化训练时,才能诱导气味偏好性的显著性改变。从对两种花香气味的联系性学习看,棉铃虫更容易将苯乙醛与蔗糖溶液进行联系性学习,而不容易将乙酸苯甲酯与蔗糖溶液进行联系性学习。从性别差异看,雌虫比雄虫具有更强的将花香气味与蔗糖溶液进行联系性学习的能力。触角电位测定结果表明,不同学习训练的棉铃虫雄成虫对两种花香气味和绿叶气味顺-3-己烯-1-醇的EAG反应值之间不存在显著性差异。总之,花香气味伴随食物资源的联系性学习经历,能够明显提高棉铃虫成虫对花香气味的选择偏好,可以此为基础进一步优化花香引诱剂的配方设计和应用技术。     

柑橘大实蝇气味结合蛋白基因BminOBP25的克隆、原核表达及组织表达分析

【目的】昆虫的气味结合蛋白(odorant binding proteins,OBPs)与嗅觉识别密切相关,在触角感受器淋巴液内运输外界的脂溶性气味分子顺利到达嗅觉受体过程中起着关键的作用。本研究对柑橘大实蝇Bactrocera minax的气味结合蛋白基因进行了克隆和表达分析,旨在更好地了解气味结合蛋白在柑橘大实蝇嗅觉识别中的作用及为进一步研究柑橘大实蝇嗅觉传递的分子机制奠定基础。【方法】利用RT-PCR和RACE技术克隆柑橘大实蝇的气味结合蛋白基因,并进行生物信息学分析;构建重组表达载体p ET28a(+)-Bmin OBP25,转化到大肠杆菌Escherichia coli BL21(DE3)中,SDS-PAGE及Western blotting鉴定重组表达蛋白;采用荧光定量PCR检测该基因在柑橘大实蝇成虫不同组织中的表达。【结果】克隆获得柑橘大实蝇气味结合蛋白基因的c DNA全长序列,命名为Bmin OBP25(Gen Bank登录号:MH181875)。测序结果表明,Bmin OBP25开放阅读框全长447 bp,编码148个氨基酸,预测分子量为17.5 k D,编码序列具有OBPs典型的6个保守半胱氨酸和6个α螺旋区域特征。在IPTG诱导下目标蛋白以6×His标签融合蛋白的形式在宿主菌中得到稳定表达。荧光定量PCR分析表明,Bmin OBP25 mRNA在成虫触角、头(去除触角)、胸、腹、足、翅和产卵器中均有表达,其中在触角、头(去除触角)、足和产卵器中表达量较高。【结论】Bmin OBP25在柑橘大实蝇成虫触角、头、足和产卵器中具有高转录活性,提示该基因在非嗅觉组织中可能也具有生理功能,特别是可能在昆虫的取食与产卵地选择过程中起重要作用,其功能还需深入研究。本研究实现了Bmin OBP25基因的原核表达,为深入研究Bmin OBP25基因的功能奠定基础。     

橘小实蝇化学通讯机制与引诱剂开发策略

实蝇是全球重大的果蔬虫害,对世界年均造成的经济损失高达20亿美元。橘小实蝇Bactrocera dorsalis是该类害虫的代表之一,每年对我国柑橘产业造成严重损失。以雄性引诱剂和蛋白饵剂为核心的诱杀技术已用于害虫监测和绿色防控,但是田间防控效果有待进一步提高。随着高通量测序技术成本的降低以及现代分子生物学技术的发展,科学家们提出先解析害虫化学感受的分子机制,鉴定关键的化学感受分子靶标,并以鉴定的新靶标设计和筛选更为稳定和高效引诱剂和食诱剂。为促进以关键化学感受分子为靶标的橘小实蝇行为调控技术的发展,本文综述了调控橘小实蝇行为的重要化学物质及其化学感受识别机制的研究现状。调控橘小实蝇行为的重要挥发物主要包括性信息素、植物挥发物和食物源蛋白气味。前两者中鉴定获得的特异性化合物质与橘小实蝇成虫的行为关系较为明确,例如性信息素中得到吡嗪类物质能够引诱雌虫,植物挥发物中的甲基丁香酚引诱雄虫,γ-辛内酯能够诱发雌虫产卵等;而后者食物源蛋白气味则由于成分复杂,在田间虽有一定效果,但缺乏特定化合物在雌雄虫具体行为中的功能验证。嗅觉感受机制中,外周神经感器与中枢触角叶仅有形态描述,不同类型嗅觉神经元的...     

Biomass deconstruction to sugars

The production of biofuels from lignocellulosic biomass relies on the depolymerization of its polysaccharide content into fermentable sugars. Accomplishing this requires pretreatment of the biomass to reduce its size, and chemical or physical alteration of the biomass polymers to enhance the susceptibility of their glycosidic linkages to enzymatic or acid catalyzed cleavage. Well-studied approaches include dilute and concentrated acid pretreatment and catalysis, and the dissolution of biomass in organic solvents. These and recently developed approaches, such as solubilization in ionic liquids, are reviewed in terms of the chemical and physical changes occurring in biomass pretreatment. As pretreatment represents one of the major costs in converting biomass to fuels, the factors that contribute to pretreatments costs, and their impact on overall process economics, are described.     

An approach to the synthesis of branched-chain amino sugars from c-methylene sugars

The reaction of 1,2:5,6-di-O-isopropylidene-3-C-methylene-α-D-ribo-hexofuranose (4) with mercuric azide in hot 50% aqueous tetrahydrofuran yielded, after reductive demercuration, 3-azido-3-deoxy-1,2:5,6-di-O-isopropylidene-3-C-methyl-α-D-glucofuranose (5). Partial, acid hydrolysis of5 afforded the diol7, which gave 3-azido-3-deoxy-1,2-O-isopropylidene-5,6-di-O-methanesulphonyl-3-C-methyl-α-D-glucofuranose (8) on sulphonylation. On hydrogenation over a platinum catalyst and N-acetylation, the dimethanesulphonate 8 furnished 3,6-acetylepimino-3,6-dideoxy-1,2-O-isopropylidene-5-O-methanesulphonyl-3-C-methyl-α-D-glucofuranose (9), which was also prepared by an analogous sequence of reactions on 3-azido-3-deoxy-1,2-O-isopropylidene-5-O-methanesulphonyl-3-C-methyl-6-O-toluene-p-sulphonyl-α-D-glucofuranose (13). The formation of the N-acetylepimine 9 establishes the D-gluco configuration for 5.1,2-O-Isopropylidene-3-C-methylene-α-D-ribo-hexofuranose (20) reacted with mercuric azide in aqueous tetrahydrofuran at ≈85° to give 3,6-anhydro-1,2-O-isopropylidene-3-C-methyl-α-D-glucofuranose (22) as a result of intramolecular participation by the C-6 hydroxyl group in the initial intermediate.     

Covalent coupling of sugars to liposomes

A procedure is described for the covalent coupling of p-aminophenyl-alpha-D-mannopyranoside, in the presence of carbodiimide, to a derivative of phosphatidylethanolamine (N-glutarylphosphatidylethanolamine) incorporated into the bilayers of multilamellar liposomes prepared by the dehydration-rehydration method. It appears that much of the phospholipid derivative exposed on the surface of the outer liposomal bilayer interacts with the aminosugar. The procedure is simple, does not destabilize liposomes and could be applied to other receptor-specific aminosugars.     

Fluorometric analysis of amino sugars and derivatized neutral sugars

A rapid and sensitive procedure for the analysis of neutral and amino sugars is presented. Neutral sugars are separated after conversion to the corresponding glycamines, while the amino sugars are analyzed without modification, using an automatic amino acid analyzer and fluorometric detection. The method has been applied for the analysis of glycoproteins and oligosaccharides of the complex and high-mannose types.     

Inositol and sugars in adaptation of tomato to salt

Tomato (Lycopersicon esculentum Mill. cv New Yorker) plants subjected to 100 millimolar NaCl plus Hoagland nutrients exhibited a pattern of wilting, recovery of turgor, and finally recovery of growth at a reduced level, which required 3 days. During the nongrowing, adaptation phase there were immediate increases in free hexoses and sucrose which declined to near control levels as growth resumed. There was a steady increase in myo-inositol content which reached its maximal level at the time of growth resumption. The myo-inositol level then remained elevated for the remainder of the experiment. Myo-inositol constituted two-thirds of the soluble carbohydrate in leaves and three-fourths of the soluble carbohydrate in roots of salt-adapted plants. Plants which were alternated daily between salt and control solutions accumulated less myo-inositol and exhibited less growth than the continuously salt-treated plants. In L. pennellii and in salt-tolerant and salt-sensitive breeding lines selected from L. esculentum × L. pennellii BC(1) and F(8), myo-inositol content was highest in the most tolerant genotypes, intermediate in the normal cultivar, and lowest in the sensitive genotype after treatment with salt.     

From imino sugars to cancer glycoproteins

This review summarizes fifty years of carbohydrate chemistry, from studies of reaction mechanisms and development of synthetic methods to the design of specific compounds for investigations of cancer glycoproteins. Through these years of intensive research, many carbohydrate derivatives were shown to be biologically relevant, for example the fragments of bacterial polysaccharides and imino sugars that were potent inhibitors of glycosidases. Oligosaccharides and O- glycopeptides with GalNAc-Ser/Thr linkages were essential for studies of cancer immunology and the specificities and inhibition of cancer glycosyltransferases. Thus carbohydrate chemistry has provided the basis for our knowledge of the biochemistry and immunology of cancer cell glycoproteins.