Bt毒素对棉铃虫雄蛾感受雌蛾性信息素EAG反应的影响

用含Bt毒素的人工饲料饲养棉铃虫Helicoverpa armigera 3龄幼虫至成虫(死亡率为40%～50%),采用触角电位 (electroantennogram, EAG) 技术,测定了雄蛾对雌蛾性信息素2种组分顺9-十六碳烯醛(Z9-16:Ald)、顺11-十六碳烯醛(Z11-16:Ald)及其混合物(Z11-16:Ald∶Z9-16:Ald=97∶3)的EAG反应。结果表明,Bt毒素对雄蛾感受性信息素单一组分和混合物的EAG反应均具促进作用;且随信息素剂量的增加,这种促进作用也随之增强。这一结果对于评价和实施延缓棉铃虫对Bt棉抗性的“庇护所"策略,具有一定的参考意义。     

粘虫雄蛾触角对其性信息素的电生理反应

用自行组装的触角电位仪,测定了粘虫Mythimna separata雄蛾蛾龄对标准化合物顺-11-十六碳烯醛(Z11-16：A1d)、顺-9-十六碳烯醛(Z9-16:Ald)和十六碳醛(16：A1d)的EAG反应的影响,分析了雄蛾触角对3种标准化合物的剂量-反应关系,发现粘虫雄蛾对Zll-16,Ald和Z9-16：Ald的剂量-反应曲线呈现出典型的“S”型,并且反应阐值较低。而对16：A1d几乎没有反应。最为重要的是检测了粘虫雄蛾对雌蛾腺体提取物的EAG反应,反应值的大小与样品中所提取的雌蛾腺体数目成正比。通过检测粘虫雄蛾对羽化不同天数,以及同一天羽化、在暗期不同时辰提取的雌蛾腺体提取物的EAG反应,证实了粘虫雄蛾的反应曲线与雌蛾释放性信息素的时辰节律呈正相关。还比较了烟青虫和粘虫雄蛾对粘虫雌蛾腺体提取物的EAG反应,间接证实了粘虫雌蛾腺体提取物中可能含有次要组分Z9-16;A1d。     

棉铃虫成虫对性信息素的电生理和行为反应研究

通过EAG和风洞实验,研究了棉铃虫雌雄成虫对性信息素组分和诱芯(Z-11-16Ald∶Z-9-16Ald=97∶3)的电生理反应。其中棉铃虫雌、雄蛾对诱芯的平均EAG反应测定值分别为1.06mV和4.32mV,分别高出对照(无性信息素空白诱芯)0.67mV和0.366mV,差异均达到极显著水平(雌蛾：t＝25.020, P≤0.01;雄蛾：t＝44.269,P≤0.01);棉铃虫雌蛾对性信息素组分(Z-11-16-Ald和Z-9.16Ald)的EAG反应值随浓度增加而增加;雄蛾在被剪除触角后与雌蛾不能正常交配,而雌蛾在被剪除触角后仍有40%的交配率,比正常雌雄蛾的交配率(70%)有所下降;在风洞实验中,雄蛾没有顺风远离诱源的飞行行为,趋向诱源的比率为81.8%,与对照有显著差异。研究表明性信息素组分对棉铃虫的交配活动有明显的影响。     

雄性棉铃虫感受性信息素的分子和神经机制研究进展

棉铃虫Helicoverpa armigera主要借助于性信息素通讯完成雌雄识别,实现交配和种群繁衍。关于棉铃虫感受性信息素机制的研究一直是我国化学生态学领域的热点和重心,研究结果有助于开发和改进棉铃虫防治的性引诱剂。本文将对棉铃虫雄虫感受雌虫释放的性信息素的机制进行综述,以期为深入研究棉铃虫及其他相关昆虫的性信息素感受的分子和神经机理提供参考。棉铃虫雌虫性信息素腺体合成和释放多种长链、饱和或非饱和的脂肪醛和醇等化合物,其中Z11-16:Ald为主要性信息素成分,Z9-16∶Ald和Z9-14∶Ald为次要性信息素成分,不同组分按一定比例混合可明显增强对雄性棉铃虫的引诱效果,而化合物Z11-16∶OH和高剂量的Z9-14∶Ald对性信息素引诱活性具有明显的抑制效果。相应地,雄性棉铃虫触角上A, B和C 3种类型的毛形感器能够感受这些信息化合物。A类型毛形感器内表达受体OR13感受Z11-16∶Ald,B类型毛形感器内表达OR14b感受Z9-14∶Ald,C类型毛形感器内表达OR6和OR16感受Z9-16∶Ald, Z9-14∶Ald, Z11-16:Ac和Z11-16∶OH。受体的表达位置和功能与不同类型毛形感器的电生理反应特性相一致。钙离子成像证明在棉铃虫触角叶内的3个扩大型神经纤维球接受这些气味信息,其中神经纤维球云状体接受Z11-16∶Ald,背中间后侧纤维球接受Z9-16∶Ald,背中间前侧纤维球接受Z9-14∶Ald, Z11-16∶Ac和Z11-16∶OH。这些研究成果在感器、受体和脑中枢水平上揭示了棉铃虫感受性信息素的机制,在这些研究基础上,我们认为需要深入开展以下方面的研究：(1)进一步鉴定相关性信息素受体的功能和定位;(2)深入研究脑内嗅觉高级中枢对性信息素信息的处理和整合神经机制;(3)明确棉铃虫性信息素感受受到寄主植物、光周期、温度、湿度等环境因素的影响及机制。     

烟青虫(Helicoverpa assulta Guenée)信息素的结构鉴定及田间试验(英语)

北京地区的烟青虫(Helicover Pa asslta Cucn(?)e)的性信息素腺体提取物经毛细管柱气相色谱分析及GC MS分析,鉴定了6种组分.这6种组分为:十六醛(16:Ald)、顺 9—十六烯醛(Z9—16:Ald)、顺11—十六烯醛(Zll 16:Ald)、顺9—十六烯醇(Z9-16:OH)、顺11—十六烯醇(Zll-16:OH)、顺9—十六烯基乙酸酯(Z9 16:OAc),比例为10.9:58.7:3.9:14.7:1.1:10.7.田间试验表明,只有16:Ald、Z9 16:Ald和Zll 16:Ald(比例为15.3:79.2:5.5)组成的三组分诱芯和Z9—16:Ald和Zll—16:Ald(比例为93.4:6.6)组成的两组分诱芯对于雄蛾有强烈的引诱活性.在3种醛为组分的诱芯中加入Z9 16:OH明显地降低引诱活性.     

小地老虎雄蛾对雌蛾性信息的EAG反应

利用触角电位记录（EAG）技术,测定了小地老虎Agrotis ypsilon (Rottemberg) 雄蛾对性信息素标准化合物Z7-12：Ac（A）、Z9-14：Ac（B）、Z11-16：Ac（C）、Z5-10：Ac（D）和Z8-12：Ac（E）的EAG反应。结果表明：这些标准化合物均能引起EAG反应,其中组分A（Z7-12：Ac）引起的反应最强,为5.65 mV,组分B（Z9-14：Ac）和C（Z11-16：Ac）居中; 组分D（Z5-10：Ac）的EAG反应值最小,为2.50 mV。二元混合物、三元混合物、四元混合物和全组分的EAG反应较高,其EAG反应值均显著高于单组分的反应值。三元混合物ABC的反应值最高,与5头雌蛾腺体的正己烷浸提液的EAG值相当。在使用剂量为0.01 ng～100 μg反应内,小地老虎雄蛾触角对性信息素各组分及其混合物的剂量反应曲线大致呈“S”形。从不同日龄雄蛾对标准化合物的反应中,发现在羽化后第3天达到最高值,之后则随日龄增加EAG反应降低。     

棉铃虫Helicverpa armigera对性外激素和植物气味物质的嗅觉反应(英文)

本文用EAG技术研究棉铃虫对性外激素和植物气味物质的嗅觉反应。供试的气味物质有棉铃虫性外激素的二种主要组分和36种与棉铃虫寄主植物有关的植物气味物质。试验结果表明：1）只有棉铃虫雄蛾对性外激素组分产生反应,二种性外激素的组分中,Z-11-16：AL能引起较强的EAG反应。2）对植物气味物质,雌雄棉铃虫之间的嗅觉反应没有明显的差异。棉铃虫对性外激素和植物气味组分的嗅觉感受过程是一个有选择性的感受过程：不同种类的气味物质能引起不同的EAG反应。只有棉铃虫雄蛾才对性外激素组分起反应,在二种性外激素组分中：主要组分：Z-11-16：AL引起的EAG反应最高,高于大多数植物气味物质。次要组分Z-9-16：AL引起的EAG反应很弱。雌、雄棉铃虫对植物气味组分的嗅觉反应的选择性表现出一致的规律：对苯甲醛和绿叶气味物质的反应最高。单萜类中的萜烯衍生物（萜类醇、醛、酯等）的触角电位反应次之。棉铃虫对大多数的供试化合物的EAG反应都很小。最后,作者讨论了性外激素和植物气味物质对棉铃虫行为的作用。     

大螟雄蛾触角对性外激素及其类似物的电生理反应

电生理试验显示出:大螟Sesamia inferens(Walker)雄蛾触角对Z11-16:Ac(A)oZ11-16:OH(B)激起强烈的触角电位(EAG)反应,Z11-16:ALD?,E11-16:Ac(D),Z9-14:Ac(E)和Z7-12:Ac(F)四种化合物也能激起较强的EAG反应;A化合物的刺激阈比B高,此两种化合物5:5比例时,激起的反应最强烈。电生理的试验推测,雄蛾触角对A和B两种化合物的感受,是通过触角内两种不同类型的嗅觉感受器。A和B不同比例混合后,田间诱蛾试验证明:在9:1,8:2,5:5的比例时,其诱蛾量远远超过单独的A化合物;E加入A与B的混合物中,起抑制诱蛾的效果,上述试验表明,Z11-16:OH是大螟的性诱剂。     

笋秀夜蛾雄蛾对性信息素化合物的电生理和行为反应

利用气质联用仪对笋秀夜蛾雌蛾性腺体粗提物成分进行了分析比对,通过触角电位(EAG)试验研究了笋秀夜蛾雄成虫对性信息素组分的电生理反应,以Y形嗅觉仪进行了室内和林间的行为生测.结果表明： 雌蛾性腺体粗提物中顺11-十六碳乙酸酯(Z11-16:Ac)和顺11-十六碳烯醇(Z11-16:OH)为笋秀夜蛾性信息素活性组分,性腺粗提物、两种化合物及其混合物均能激发雄蛾明显的EAG反应,且EAG反应值随性信息素组分浓度增加而增加.Z11-16:Ac和Z11-16:OH按57∶43配置成的二元混合物所激发的EAG反应强于同等剂量下的单一组分.室内的行为生测和林间诱捕试验结果与EAG反应基本一致,Z11-16:Ac+Z11-16:OH(57∶43)混合物对雄蛾引诱力最强,在林间单诱捕器(诱芯浓度为10⁴ng·μL^-1)的平均诱捕量达到(48.5±6.7)头.     

温度对二化螟性信息素通讯的影响

环境因素影响昆虫两性间的化学通讯,也影响性信息素技术的田间防治效果.本文探讨了温度对二化螟雌蛾性信息素产生以及雄蛾对性信息素触角电位反应的影响,以期为田间二化螟的性信息素防治提供指导.在二化螟蛹期和成虫期进行不同温度处理(15、20、25、30和35 ℃),然后利用气相色谱仪(GC)分析雌蛾性腺内各性信息素组分的含量及比例,同时利用触角电位仪(EAG)测定雄蛾对性信息素组分的电生理反应.结果表明: 25 ℃处理中雌蛾性腺内3个性信息素组分(Z9-16:Ald、Z11-16:Ald和Z13-18:Ald)的含量均显著高于其他温度处理(15、20和30 ℃),且25 ℃处理中Z13-18:Ald的相对比例也显著低于其他温度处理.就雄蛾对性信息素的敏感性而言,对3种性信息素单一组分及特定比例混合物的EAG反应在15～25 ℃间没有显著差异,但在25～35 ℃间(Z13-18:Ald在30～35 ℃间)随温度升高呈下降趋势,且30 ℃较25 ℃显著降低,35 ℃较30 ℃又显著降低.综合分析认为,二化螟性信息素通讯的适宜温度为20～25 ℃,温度过高或过低均不利于二化螟两性间的正常化学通讯.研究结果为二化螟性信息素防治技术的合理应用及极端温度条件下害虫种群发生的预测预报,提供了重要参考.     

Crystal structure of the vertebrate NADP(H)-dependent alcohol dehydrogenase (ADH8)

The amphibian enzyme ADH8, previously named class IV-like, is the only known vertebrate alcohol dehydrogenase (ADH) with specificity towards NADP(H). The three-dimensional structures of ADH8 and of the binary complex ADH8-NADP(+) have been now determined and refined to resolutions of 2.2A and 1.8A, respectively. The coenzyme and substrate specificity of ADH8, that has 50-65% sequence identity with vertebrate NAD(H)-dependent ADHs, suggest a role in aldehyde reduction probably as a retinal reductase. The large volume of the substrate-binding pocket can explain both the high catalytic efficiency of ADH8 with retinoids and the high K(m) value for ethanol. Preference of NADP(H) appears to be achieved by the presence in ADH8 of the triad Gly223-Thr224-His225 and the recruitment of conserved Lys228, which define a binding pocket for the terminal phosphate group of the cofactor. NADP(H) binds to ADH8 in an extended conformation that superimposes well with the NAD(H) molecules found in NAD(H)-dependent ADH complexes. No additional reshaping of the dinucleotide-binding site is observed which explains why NAD(H) can also be used as a cofactor by ADH8. The structural features support the classification of ADH8 as an independent ADH class.     

A cotton mitogen-activated protein kinase （GhMPK6） is involved in ABA-induced CAT1 expression and H2O2 production

The mitogen-activated protein kinase (MAPK) cascade is one of the major and evolutionally conserved signaling pathways and plays a pivotal role in the regulation of stress and developmental signals in plants.Here,we identified one gene,GhMPK6,encoding an MAPK protein in cotton.GFP fluorescence assay demonstrated that GhMAPK6 is a cytoplasm localized protein.Quantitative RT-PCR analysis revealed that mRNA accumulation of GhMPK6 was significantly promoted by abscisic acid (ABA).Overexpression of GhMPK6 gene in the T-DNA insertion mutant atmkkl (SALK_015914) conferred a wild-type phenotype to the transgenic plants in response to ABA.Under ABA treatment,cotyledon greening/expansion in GhMPK6 transgenic lines and wild type was significantly inhibited,whereas the atmkkl mutant showed a relatively high cotyledon greening/expansion ratio.Furthermore,CAT1 expression and H2O2 levels in leaves of GhMPK6 transgenic lines and wild type were remarkably higher than those of atmkkl mutant with ABA treatment.Collectively,our results suggested that GhMPK6 may play an important role in ABA-induced CAT1 expression and H2O2 production.     

Enhancement of the NAD(P)(H) Pool in Saccharomyces cerevisiae

Asymmetric biosyntheses allow for an efficient production of chiral building blocks. The application of whole cells as biocatalysts for asymmetric syntheses is advantageous because they already contain the essential coenzymes NAD(H) or NADP(H), which additionally can be regenerated in the cells. Unfortunately, reduced catalytic activity compared to the oxidoreductase activity is observed in many cases during whole‐cell biotransformation. This may be caused by low intracellular coenzyme pool sizes and/or a decline in intracellular coenzyme concentrations. To enhance the intracellular coenzyme pool sizes, the effects of the precursor metabolites adenine and nicotinic acid on the intracellular accumulation of NAD(H) and NADP(H) were studied in Saccharomyces cerevisiae. Based on the results of simple batch experiments with different precursor additions, fed‐batch processes for the production of yeast cells with enhanced NAD(H) or enhanced NADP(H) pool sizes were developed. Supplementation of the feed medium with 95 mM adenine and 9.5 mM nicotinic acid resulted in an increase of the intracellular NAD(H) concentration by a factor of 10 at the end of the fed‐batch process compared to the reference process. The final NAD(H) concentration remains unchanged if the feed medium was solely supplemented with 95 mM adenine, but intracellular NADP(H) was increased by a factor of 4. The effects of NADP(H) pool sizes on the asymmetric reduction of ethyl‐4‐chloro acetoacetate (CAAE) to the corresponding (S)‐4‐chloro‐3‐hydroxybutanoate (S‐CHBE) was evaluated with S. cerevisiae FasB His6 as an example. An intracellular threshold concentration above 0.07 mM NADP(H) was sufficient to increase the biocatalytic S‐CHBE productivity by 25 % compared to lower intracellular NADP(H) concentrations.     

NAD(H) enhances the Cu(II)-mediated inactivation of lactate dehydrogenase by increasing the accessibility of sulfhydryl groups

Copper ions are known to inactivate a variety of enzymes, and lactate dehydrogenase (LDH) is exceptionally sensitive to the presence of this metal. We now found that NADH strongly enhances the Cu(II)-mediated loss of LDH activity. Surprisingly, NADH was not oxidized in this process and also NAD⁺ promoted the Cu(II)-dependent inactivation of LDH. Catalase only partly protected the enzyme, whereas hypoxia even enhanced LDH inactivation. NAD(H) accelerated sulfhydryl (SH) group oxidation of LDH by 5,5-dithio-bis(2-nitrobenzoic acid) (DTNB), and, vice versa, LDH-mediated Cu(II) reduction. LDH activity was preserved by thiol donators and pyruvate and partially preserved by lactate and oxamate. Our results suggest that reactive oxygen species (ROS) are of minor importance for the inactivation of LDH induced by Cu(II)/NADH. We propose that conformational changes of the enzymes' active sites induced by NAD(H)-binding increase the accessibility of active sites' cysteine residues to Cu(II) thereby accelerating their oxidation and, consequently, loss of catalytic activity.     

New Discoveries of the Genus Hippophae L. (Elaeagnaceae)

This paper represents new discoveries of the genus Hippophae L, including two new sections: i. e. Sect. I. Hippophae and Sect. II. Gyantsenses Lian, a new rank species H. gyantsensis (Rousi) Lian, as well as a new record of H. rhamnoides L. subsp. turkestanica Rousi in Gansu. Besides, a key to the sections and species is provided and an account of the new classification scheme on the genus is given.     

椭圆萝卜螺Radix swinhoei (H. Adams)对三种沉水植物的牧食选择

报道了2005年7～9月在太湖试验基地进行的椭圆萝卜螺对沉水植物牧食的实验结果。结果表明,椭圆萝卜螺对3种沉水植物的平均牧食率为7.87mg•g^－１•d^－１,其中对苦草的牧食率最高（13.63 mg•g^－１•d^－１）,马来眼子菜次之（9.66mg•g^－１•d^－１）,轮叶黑藻最低（0.31mg•g^－１•d^－１）,且牧食率与螺规格呈显著负相关。椭圆萝卜螺对沉水植物的牧食具有选择性,喜食苦草而较少选食其他两种沉水植物。椭圆萝卜螺的食物选择性能力与其规格有关,随着生长对沉水植物的选择性加强。探讨了椭圆萝卜螺对沉水植物的选食机理。      

即时浸酸显著提高滞育性家蚕卵辅酶Ⅰ和Ⅱ含量

即时浸酸在阻止家蚕Bombyx mori卵滞育发动的同时, 提高了其呼吸耗氧量, 抑制了山梨醇积累。本研究利用HPLC法测定了家蚕滞育卵和5 min即时浸酸滞育性卵中辅酶Ⅰ和Ⅱ含量。结果表明： 产下后24-72 h, 家蚕滞育卵中NAD, NADH, NADP和NADPH含量分别下降了30%, 37%, 50%和4%; 而即时浸酸滞育性卵中分别增加了77%, 46%, 142%和241%。不过, 即时浸酸并未显著改变滞育性家蚕卵中NADH/NAD和NADPH/NADP比值。据此推测, 即时浸酸提高滞育性家蚕卵辅酶Ⅰ含量与其呼吸耗氧量增加有关; 即时浸酸显著提高辅酶Ⅱ含量与山梨醇积累抑制无关, 而主要与生物合成加强有关。     

椭圆萝卜螺Radix swinhoei (H. Adams) 对三种沉水植物的牧食选择

报道了2005年7～9月在太湖试验基地进行的椭圆萝卜螺对沉水植物牧食的实验结果.结果表明,椭圆萝卜螺对3种沉水植物的平均牧食率为7.87mg·g-1·d-1,其中对苦草的牧食率最高(13.63 mg·g-1·d-1),马来眼子菜次之(9.66mg·g-1·d-1),轮叶黑藻最低(0.31mg·g-1·d-1),且牧食率与螺规格呈显著负相关.椭圆萝卜螺对沉水植物的牧食具有选择性,喜食苦草而较少选食其他两种沉水植物.椭圆萝卜螺的食物选择性能力与其规格有关,随着生长对沉水植物的选择性加强.探讨了椭圆萝卜螺对沉水植物的选食机理.