瓢虫和草蛉对小麦挥发物组分的行为及电生理反应

利用触角电位（electroantennogram, EAG）和嗅觉测定技术,比较分析了4种捕食性天敌昆虫七星瓢虫Coccinella septempunctata、龟纹瓢虫Propylaea japonica、中华通草蛉Chrysoperla sinica和大草蛉Chrysopa septempunctata对麦蚜取食诱导小麦挥发物的行为和电生理反应,揭示了瓢虫及草蛉类天敌昆虫的嗅觉反应特点。4种捕食性天敌昆虫对麦蚜取食诱导挥发物都有较高的EAG反应值,七星瓢虫和龟纹瓢虫对6-甲基-5_庚烯-2-酮、6-甲基-5-庚烯-2-醇的反应值较大;中华通草蛉和大草蛉对6-甲基-5-庚烯-2-醇和水杨酸甲酯的反应值较大,七星瓢虫对6-甲基-5-庚烯-2-醇的反应值最大,为0.96±0.18 mV;4种天敌昆虫对苯甲醛的EAG反应值较低,对反-2-己烯醛无反应。“Y”型管嗅觉测定结果表明,4种天敌昆虫对2-莰烯、6-甲基-5-庚烯-2-酮、6-甲基-5-庚烯-2-醇和水杨酸甲酯具有正趋性。说明4种多食性的捕食性天敌昆虫对麦蚜取食诱导挥发物各组分的嗅觉与行为反应各具特点;寄主麦蚜生境中的嗅觉线索在这4种捕食性天敌昆虫的寄主定位和生境选择中起重要作用。     

Lycopene accumulation affects the biosynthesis of some carotenoid-related volatiles independent of ethylene in tomato

For elucidating the regulatory mechanism of ethylene on carotenoid-related volatiles (open chain) compounds and the relationship between lycopene and carotenoid-related volatiles,transgenic tomato fruits in which ACC synthase was suppressed were used.The transgenic tomato fruit showed a significant reduction of lycopene and aroma volatiles with low ethylene production.6-methyl-5-hepten-2-one,6-methyl-5-hepten-2-ol and geranylacetone,which were suspected to be lycopene degradation products,were lower than those in wild type tomato fruits.In order to identify whether lycopene accumulation effects the biosynthesis of some carotenoid-related volatiles independent of ethylene in tomato or not,the capability of both wild type and transgenic tomato fruits discs to convert lycopene into carotenoid-related volatiles was evaluated.The data showed that external lycopene could convert into 6-methyl-5-hepten-2-one and 6-methyl-5-hepten-2-ol in vivo,Indicating that the strong inhibition of ethylene production had no effect on enzymes in the biosynthesis pathway of some carotenoid-related volatiles.Therefore,in ACS-suppression transgenic tomato fruits,the low levels of 6-methyl-5-hepten-2-one,6-methyl-5-hepten-2-ol was due to decreased lycopene accumulation,not ethylene production.Ethylene only affected the accumulation of lycopene,and then indirectly influenceed the level of lycopene-related volatiles.     

不同营养层次挥发物对燕麦蚜茧蜂寄主搜寻行为的影响

“Ｙ”型管嗅觉计及风洞测定试验明,小麦植株,麦长管蚜（Sitobion avenae),禾谷缢管蚜（Rhopalosiphum padi)对燕麦蚜蜂（Aphidius avenae)雌蜂的吸引作用较小,而有蚜植株及蚜害植株对其吸引作用较大,并以麦长管蚜有蚜植株的吸引作用最强,尽管该蜂对禾谷缢管蚜的寄生率极你,工作量 由其危害诱导产生的挥发性信息化僵物对该蜂仍具有较强的吸引作用,GC－MS鉴定结果表明,麦蚜取食诱导的挥发性信息化合物主要是2－莰烯,6－甲基－5－已烯－2－酮,顺－3－已酰酸酯有水杨酸甲酯,其中6－甲基－5－已烯－2－酮和6－甲基－5－已烯－2－醇对燕麦蚜划蜂的吸引作用最强,水杨酸酯无明显吸引作用。     

Bioconversion of citronellol by Botrytis cinerea

Summary Bioconversion of citronellol 1 was studied with four strains of Botrytis cinerea. Using grape must predominant transformation of 1 to 2,6-dimethyl-1,8-octandiol 2 and (E)-2,6-dimethyl-2-octen-1,8-diol 3 was observed. In minor amounts 2,6-dimethyl-2,8-octandiol 4, two p-menthan-3,8-diol isomers 5a, 5b, (Z)-2,6-dimethyl-2-octen-1,8-diol 6, isopulegol 7, 2-methyl-2-hepten-6-one-1-ol 8 and 2-methyl--butyrolactone 9 were found. Using a small amount of grape must in a synthetic medium (1:700) the bioconversion products 2, 4, 5a and 5b were absent, but additionally 2-methyl-2-hepten-6-one 10, 2-methyl-2-hepten-6-ol 11 and citronellic acid 12 were detected. The results obtained were strongly dependent on the strains used; one strain did not show any metabolic activity against 1. The bioconversion products were identified by capillary gas chromatography (HRGC) and coupled HRGC techniques, i.e. on-line — mass spectrometry (HRGC-MS) and — Fourier transform infrared spectroscopy (HRGC-FTIR).     

Biotransformation of terpenes by fungi: Study of the pathways involved

The biotransformation of the pure terpene alcohols geraniol and nerol, the mixture of the alcohols, ‘citrol’, and the mixture of the aldehydes, citral, to 6-methyl-5-hepten-2-one by sporulated surface cultures of Penicillium digitatum was compared. It was found that citral was converted faster than the alcohols but gave a lower overall yield of ≈76%, whereas the pure alcohols and their mixture, ‘citrol’, gave a yield of ≈83%. It was also established that the bioconversion over prolonged periods was possible with an overall yield of 80–90% depending on the substrate used. The bioconversion of nerol to 6-methyl-5-hepten-2-one by a spore suspension was also shown. The pathways involved in the biotransformation of geraniol and citral to 6-methyl-5-hepten-2-one are also discussed.     

Microbial transformation of geraniol and nerol by Botrytis cinerea

Summary Biotransformation of geraniol 1A and nerol 1B was studied with four strains of Botrytis cinerea and three growth media. Using grape must predominant conversion of 1A/1B to E-3,7-dimethyl-2-octen-1,8-diol 5 and 2Z,6E-3,7-dimethyl-2,6-octadien-1,8-diol 16B was observed. However, with one strain and 1A, E-2-methyl-2-hepten-6-one-1-ol 2B, 7-hydroxy-6-methyl-2-heptanone 3 and p-menth-1-ene-9-ol 7 were identified as major metabolites. As further fungal bioconversion products of 1A/1B were detected: Z-2-methyl-2-hepten-6-one-1-ol 2A, 2E,6Z-, 2E,6E-and 2Z,6Z-3,7-dimethyl-2,6-octadien-1,8-diol 4A/4B/16A, Z-3,7-dimethyl-2-octen-1,8-diol 17, 3,7-dimethyl-1,8-octandiol 6, 2E,6E-8-hydroxy-2,6-dimethyl-2,6-octadienal 8, geranial and neral 9, 18, citronellol 10, Z- and E-2,6-dimethyl-2,7-octadien-1,6-diol 13A/13B, 6-hydroxy-2,6-dimethyl-2,7-octadienal 14 as well as 2,6-dimethyl-7-octen-1,6-diol 15. Using synthetic growth medium again -hydroxylation reactions were observed, but 2-methyl-2-hepten-6-one 11 and 7 were also identified as major bioconversion products of 1A and 1B, respectively. Additionally, 2-methyl-2-hepten-6-ol 12 was detected and, using 1B, also traces of 2Z,6E-8-hydroxy-2,6-dimethyl-2,6-octadienal 19 and two 3,9-epoxy-p-menth-1-ene isomers 20A/20B were found. Addition of small amounts of grape must to the synthetic medium (1:700 to 5:700) influenced both the yields of metabolites and their qualitative and quantitative distribution. Identifications of biotransformation products of 1A/1B were performed by capillary gas chromatography (HRGC) and coupled HRGC techniques, i.2. on-line-mass spectrometry (HRGC-MS) and-Fourier transform infrared spectroscopy (HRGC-FTIR) after extractive sample preparation.     

红火蚁工蚁对棉蚜诱导的棉花挥发物的嗅觉和行为反应

【目的】红火蚁 Solenopsis invicta 与棉蚜 Aphis gossypii 存在兼性共生关系,红火蚁可能利用棉蚜危害诱导棉花释放的挥发物定位棉蚜。本研究将测试红火蚁工蚁对棉花挥发物的嗅觉和行为反应。【方法】使用Y型管实验测试红火蚁工蚁对棉花气味的行为反应;以红火蚁告警信息素2-乙基-3,5(6)-二甲基吡嗪为阳性对照,测试红火蚁工蚁对不同剂量(100, 10, 1 和0.1 μg)的9种棉花挥发物组分[α-蒎烯、β-蒎烯、β-石竹烯、( E, E )-4,8,12-三甲基-1,3,7,11-十三碳四烯(TMTT)、( E )-4,8-二甲基-1,3,7-壬三烯(DMNT)、辛醛、6-甲基-5-庚烯-2-酮、顺-3-己烯基乙酸酯和水杨酸甲酯]的触角电位反应;再利用Y型嗅觉仪测试这些挥发物对红火蚁工蚁的行为选择影响。【结果】结果表明,受棉蚜为害的棉花较健康棉花对红火蚁工蚁具有极显著的引诱效果。红火蚁对9种挥发物组分的EAG反应随着剂量升高而升高。各化合物在100 μg剂量时EAG反应值最大,其中,工蚁对水杨酸甲酯和6-甲基-5-庚烯-2-酮这两个化合物反应最强。在行为选择实验中,化合物水杨酸甲酯、6-甲基-5-庚烯-2-酮和DMNT对红火蚁工蚁均具有显著的引诱效果。【结论】棉蚜诱导的棉花挥发物中水杨酸甲酯和6-甲基-5-庚烯-2-酮对红火蚁有显著的引诱效果,这2种化合物可能在红火蚁定位棉蚜、建立共生关系中起着关键的作用。     

Photosensitized Oxygenation of Lycopene

Irradiation of lycopene in an atmosphere of oxygen and in the presence of a sensitizer (methylene blue) led to the formation of 2-methyl-2-hepten-6-one and apo-6’-lycopenal. A reaction pathway via a dioxetane intermediate is proposed.     

麦长管蚜和禾谷缢管蚜对小麦植株挥发物及蚜害诱导挥发物的行为反应

用四臂嗅觉计测定了麦长管蚜Macrosiphum avenae和禾谷缢管蚜Rhopalosiphum padi对小麦植株挥发物及麦蚜取食诱导挥发物的行为反应,揭示了2种麦蚜的嗅觉及小麦植株的诱导防御反应特点.在所选的13种小麦植株挥发物及蚜害诱导挥发物组分中,6-甲基-5-庚烯-2-酮、6-甲基-5-庚烯-2-醇和水杨酸甲酯对这2种蚜虫表现出强的驱拒作用;反-2-己烯醛对麦长管蚜的有翅和无翅蚜的吸引作用最强;反-2-己烯醇对禾谷缢管蚜的无翅蚜吸引作用最强,反-3-己酰醋酸酯对禾谷缢管蚜有翅蚜的吸引作用最强.说明麦蚜取食能诱导小麦植株的防御反应,麦长管蚜和禾谷缢管蚜及其不同蚜型间嗅觉反应的特点不同.     

Biotransformations with Rhizopus arrhizus: Preparation of enantiomers of sulcatol

Summary Microbial reduction of 6-methyl-5-hepten-2-one (1) and hydrolysis of (±)-sulcatol acetate (4) yielded (S)-(+)-sulcatol (2) and (R)-(-)-sulcatol (5) respectively using Rhizopus arrhizus.     

Identification of volatile emissions from Platypus mutatus (=sulcatus) (Coleoptera: Platypodidae) and their behavioral activity

We report here the identification and behavioral activity of volatile compounds emitted by male Platypus mutatus (=sulcatus) Chapuis while boring galleries in living poplar, Populus deltoides Marshall, trees. Headspace analysis using solid phase microextraction techniques showed the presence of 6-methyl-5-hepten-2-ol (sulcatol) and 6-methyl-5-hepten-2-one (sulcatone). Only one enantiomer of sulcatol, retusol, was found to be part of the volatile emission. Behavioral assays showed that females are more attracted than males to galleries with boring males inside. Both sulcatol and sulcatone elicited electroantennographic responses by female P. mutatus. Furthermore, behavioral bioassays showed that both sulcatol and sulcatone elicit behaviorally attractive responses by females. These results suggest that male P. mutatus releases a sex pheromone composed mainly of retusol and sulcatone.     

An ambiguous function of an alarm pheromone in the collective displays of the Australian meat ant,Iridomyrmex purpureus

Alarm pheromones, which have been documented in many species of ants, are thought to elicit responses related to aggressive or defensive behaviour. The volatile odour 6-methyl-5-hepten-2-one is described as an alarm pheromone in several species of ants, including the Australian meat ant, Iridomyrmex purpureus. The alarm pheromone is released by displaying workers that aggregate in the characteristic collective display grounds, located mid-way between colonies or near contested food trees. Workers are typically more aggressive at the latter location, and the alarm pheromone may regulate the collective level of aggression. We investigated this possibility by exposing displaying workers to synthesised alarm pheromone 6-methyl-5-hepten-2-one in a field experiment, and measuring their aggressive behaviour. We found no evidence that exposure to synthesised alarm pheromone caused changes in the aggressive level of workers. Subsequent field experiments revealed that the pheromone functions as an attractant, thereby increasing the density of displaying workers. More densely populated workers also display more aggressively, indicating that the interaction rate of displaying workers may determine the level of aggression in collective displays. This underlying mechanism can explain why displaying ants are more aggressive at the more densely populated food-tree locations than those displaying at locations midway between two neighbouring colony nest sites.     

Semiochemicals associated to spacing behaviour of the bird cherry-oat aphid Rhopalosiphum padi L. (Hem., Aphididae) do not affect the olfactometric behaviour of the cereal aphid parasitoid Aphidius rhopalosiphi De Stephani-Pérez (Hym., Braconidae)

Volatiles produced by the interaction of Rhopalosiphum padi and wheat, and semiochemicals which elicit the spacing behaviour of R. padi on wheat and oat, were evaluated in an olfactometer against the cereal aphid parasitoid Aphidius rhopalosiphi . The parasitoid was attracted by volatiles produced by the R. padi -wheat interaction at high density of aphids, but not by the R. padi -wheat interaction at low density. Compounds produced by the interaction of wheat or oat that was infested with a high density of aphids (approximately 9 aphids/cm²), 6-methyl-5-hepten-2-one (MHO), 6-methyl-5-hepten-2-ol (MHOH), 2-tridecanone (2-T), and methyl salicylate (MS), neither attracted nor repelled A. rhopalosiphi as pure compounds or in the naturally occurring mixture. The results are discussed in terms of the use of semiochemicals and parasitoids in the integrated management of aphid pests.     

Electrophysiological and behavioral responses of Asian and European honeybees to pear flower volatiles

Honeybee pollination behavior is influenced by flower volatiles, which honeybees sense via olfactory receptors. Honeybees are only weakly attracted to pear flowers. To investigate the potential reasons, we extracted and determined the floral volatile compounds from three pear cultivars (Su, Ya, and Xuehua) using headspace solid-phase micro-extraction (HS-SPME) and gas chromatography-mass spectrometry (GC–MS). The effects of pear flower volatiles on the Asian honeybee (Apis cerana cerana Fabricius) and the European honeybee (Apis mellifera ligustica Spinola) were determined by electroantennogram (EAG) assays and behavioral tests in a three-arm olfactometer. Among the 76 flower volatiles detected with GC–MS, 21 were found in all three pear cultivars, accounting for approximately 70% of the total volatile content. 3-Methyl-1-butanol and (+)-limonene volatiles had the highest relative content. Five compounds elicited strong EAG responses in both bee species: 2-methylbutyraldehyde, 1-nonanal, 6-methyl-5-hepten-2-one, 3-methyl-1-butanol, and (+)-limonene. Neither bee species showed positive taxis to these volatiles. In behavioral tests, A. mellifera ligustica showed a low preference for 6-methyl-5-hepten-2-one (20%, 400 µg/µL) and 2-phenethyl alcohol (16.7%, 400 µg/µL). Apis cerana cerana showed a low preference for 6-methyl-5-hepten-2-one (6.7%, 400 µg/µL) and 1-nonanal (10%, 400 µg/µL), whereas its preferences for 3-methyl-1-butanol (43.3%, 400 µg/µL) and α-farnesene (40%, 400 µg/µL) were similar to that for the control. Therefore, a lack of attractive volatile compounds could explain why honeybees are only weakly attracted to pear flowers. Therefore, to achieve acceptable pollination in pear orchards, we suggest using flower-scent sugar syrup feeding and a saturation pollination strategy.     

Sulcatol: population aggregation pheromone in the scolytid beetle, Gnathotrichus sulcatus

The population aggregation pheromone produced by males of Gnathotrichus sulcatus, a timber pest, has been identified from boring dust as a $\text{65}\text{35}$ mixture of the (S)-(+) and the (R)-(?) enantiomers of 6-methyl-5-hepten-2-ol. In field studies beetles were attracted in a 2·65 female: 1 male ratio by racemic synthetic pheromone.     

The ability of Bipolaris sorokiniana to modify geraniol and (-)-alpha-bisabolol as exogenous substrates

The biocatalytic potential of Bipolaris sorokiniana was investigated in its ability to modify the monoterpene geraniol and the sesquiterpene alpha-bisabolol as exogenous substrates, using phosphate buffer as reaction medium. The cultures showed a promising oxidative profile, with conversion of geraniol to 6-methyl-5-hepten-2-one (74.9% yield) in a 5-day incubation and alpha-bisabolol to bisabolol oxide B (84.2% yield), in a 7-day incubation.     

传粉榕小蜂与非传粉小蜂间寄主识别行为的趋同进化

在高度专性传粉的榕树-榕小蜂互惠共生系统中普遍存在着一些非传粉小蜂,它们中的一些种类进入果腔后也能为榕树传粉,且在形态和物候上已与传粉榕小蜂发生了趋同进化。但其寄主识别行为是否也与传粉榕小蜂发生了趋同进化还不得而知。我们在西双版纳选择了钝叶榕(Ficuscurtipes)及其3种进果繁殖小蜂开展了相关的行为实验。3种小蜂中,1种是钝叶榕的专性传粉榕小蜂(Eupristina sp.),另外2种是寄居性非传粉小蜂(杨氏金小蜂Diaziellayangi和Lipothymus sp.),这2种非传粉小蜂进入果腔后也像传粉榕小蜂那样为钝叶榕传粉。我们以钝叶榕不同发育时期的榕果及这3种小蜂为材料,采用Y型嗅觉仪观察了这3种小蜂对各发育时期榕果和信息化学物质6-甲基-5-庚烯-2-醇、6-甲基-5-庚烯-2-酮及这2种化合物的混合物的选择行为。结果表明,当提供雌花期榕果与其他发育时期榕果和空气对照供这3种小蜂选择时,它们均显著地偏向于选择雌花期榕果;当提供雄花期榕果与其他发育时期榕果和空气对照供这3种小蜂选择时,它们均显著地偏向于选择其他发育时期榕果和空气对照,即都会避开雄花期榕果;此外,这3种小蜂均对钝叶榕雌花期果释放的一种主要化合物6-甲基-5-庚烯-2-醇的同一剂量(1μL)表现出显著的偏好。这一结果为传粉榕小蜂与非传粉小蜂间的寄主识别行为趋同进化的假说提供了证据。     

Photochemical system for regenerating NADPH from NADP with use of immobilized chloroplasts

Spinach chloroplasts were immobilized in 2% agar gel. Crude ferredoxin and NADP–ferredoxin oxidoreductase isolated from spinach were used as electron carriers. The activity of the NADP reduction by immobilized chloroplasts increased with increasing ferredoxin concentration and the maximum activity was obtained at 8μM ferredoxin. The saturation of NADP reduction was observed at a light intensity of over 1000 lx. The optimum pH and temperature of NADP reduction were 8 and 25°C, respectively. The reduced NADP in a reaction medium increased linearly with increasing reaction time under illumination. NADP was continuously reduced for 2 hr with a hollow-fiber reactor containing immobilized chloroplasts. NADPH and NADP were separated with a hollow-fiber dialyzer from ferredoxin and NADP–ferredoxin oxidoreductase, which were reused. The conversion ratio of NADP to NADPH was from 40 to 80%.     

Preparation of the gemini detergent-lipase complexes and their high enzymatic activities in the transesterifications in homogeneous organic solvents

Lipase and newly synthesized gemini-type detergent were mixed in an aqueous phosphate buffer solution and lyophilized. Due to complex formation between the substances it was possible to dissolve or at least finely disperse these preparations in organic media. The lipase-detergent complexes were used to catalyse the irreversible transesterfication of 6-methyl-5-hepten-2-ol (sulcatol) or 2,2-dimethyl-1,3-dioxolane-4-methanol (solketal) with vinyl or isopropenyl carboxylate in organic solvents. The complexes were considerably more active than enzyme powder or the complexes prepared with conventional synthesized detergents in organic media. © Rapid Science Ltd. 1998     

Immobilized Enzyme Three-Phase Reactors for Oxidation of Cephalosporin C

The enzymatic oxidation of Cephalosporin C (CEPHC) was catalyzed by D-aminoacid oxidase, from the red yeast Trigonopsis variabilis, immobilized on Duolite A365. The study was performed in two different three phase bioreactors, gas-liquid-solid (immobilized enzyme): the fluidized-bed batch reactor, fed continuously with oxygen and discontinuously with CEPHC, and the UF-membrane reactor continuously fed with both substrates. Only the first reactor allowed significant product yield (>70%) while the second was a very useful tool for laboratory investigation of both bioconversion kinetics and enzyme stability.

Optimum reaction temperature was 15d`C for the control of CEPHC spontaneous degradation (roughly 15% in 30 h), and enzyme deactivation (half-life greater than 30 h). Immobilization improved (one order of magnitude longer half-life) enzyme resistance to mechanical stresses induced by liquid stirring and gas bubbling. Roughly 0.04g of CEPHC was adsorbed per gram of enzyme carrier. The limiting step in oxygen transfer was the gas to liquid transport. In order to attain kinetic control of the bioconversion the mildest conditions were atmospheric gas pressure and oxygen flow rate equal to 2 × 10 ²NmL/s per mL of liquid phase.