Transport of a hydrophobic biosynthetic precursor by lipophorin in the hemolymph of a geometrid female moth which secretes an epoxyalkenyl sex pheromone

Previous experiments with a geometrid species, Ascotis selenaria cretacea, have suggested that a pheromonal C19 3,4-epoxy-6,9-diene is biosynthesized from the corresponding 3,6,9-triene produced outside a pheromone gland and transported to it via hemolymph after association with lipophorin. In order to clarify this transport, high-density lipophorin (HDLp) in the female moths showing two bands (apoLp I with ca. 250 kDa and apoLp II with ca. 80 kDa) on an SDS-PAGE was purified by KBr equilibrium density-gradient ultracentrifugation, and the association of the triene was confirmed by GC-MS analysis of a solvent extract from the isolated protein. Next, the role of HDLp was revealed by a topical application of the deuterated trienyl precursor to the abdomens of the females. The trienyl precursor was associated with HDLp. In their pheromone glands, the triene and the deuterated epoxy pheromone were detected, indicating movement of the triene via the hemolymph. Experiments with male moths of A. s. cretacea and female moths of Bombyx mori showed the same association of HDLp with the triene topically applied. This result suggested that the adult females of A. s. cretacea did not develop HDLp specialized in the triene transport. Furthermore, the topical application of a mixture including the trienyl precursor and two other related hydrocarbons showed equal amounts of association by HDLp but selective delivery of the precursor to pheromone glands in the A. s. cretacea females.     

Selectivity and neuroendocrine regulation of the precursor uptake by pheromone glands from hemolymph in geometrid female moths, which secrete epoxyalkenyl sex pheromones

Macrolepidopteran female moths in families such as Geometridae produce epoxyalkenyl sex pheromones, which are biosynthesized via epoxidation of polyunsaturated hydrocarbons in their pheromone glands. The precursors, however, are expected to be produced outside of the pheromone glands, probably in oenocytes or in the fat body, and transported to the glands via hemolymph. Based on these facts, the selectivity of the epoxidation substrates and of the precursor uptake by pheromone glands was examined with two geometrid species, Hemerophila artilineata and Ascotis selenaria cretacea, using binary mixtures of deuterated precursors and their analogs, which were topically applied to the pheromone glands or injected into the abdomen. GC-MS measurements of pheromone extracts showed equal epoxidation of two polyenes, indicating a low selectivity for both processes, while the epoxidation proceeded at only one double bond specific to each species. This result makes it possible to conclude that the formation of species-specific epoxyalkenyl pheromones results from the rigid formation of polyunsaturated precursors and their epoxidation at a fixed position. Next, the neuroendocrine regulation of these processes was studied with in vivo and in vitro experiments using decapitated females. The epoxy pheromones disappeared completely within 36 h of decapitation, and epoxidation of the injected precursors was not detected in the decapitated females, which restarted the reaction by treatment with a pheromone biosynthesis-activating neuropeptide (PBAN). The precursors topically applied to glands of the decapitated females, however, were converted into epoxy pheromones without PBAN, indicating that this neuropeptide hormone accelerated the precursor uptake by pheromone glands but not the epoxidation already underway in the glands.     

Identification of cuticular hydrocarbons and the alkene precursor to the pheromone in hemolymph of the female gypsy moth, Lymantria dispar

Hydrocarbons were extracted from the surface of the cuticle and from the hemolymph of adult female gypsy moths. GC and GC/MS analysis indicated that the cuticular hydrocarbons with chain lengths >21 carbons were the same as those found in the hemolymph. These consisted of mostly saturated straight chain hydrocarbons with heptacosane the major component. Methyl branched hydrocarbons were also identified including a series of tetramethylalkanes with chain lengths of 30, 32, and 34 carbons. In addition to those found on the cuticle surface, the hemolymph contained the alkene pheromone precursor, 2-methyl-Z7-octadecene and two saturated analogues, 2-methyl-octadecane and 2-methyl-hexadecane. No evidence was obtained for the presence of the pheromone 2-methyl-7, 8-epoxy-octadecane in the hemolymph. Pheromone gland extracts indicated that small amounts (<1 ng) of the alkene precursor were also present in the gland. Relatively larger amounts of the alkene precursor were found in the hemolymph at the time when pheromone titers were higher on the gland. The presence of the hydrocarbon pheromone precursor in the hemolymph is discussed in relation to possible biosynthetic pathways for producing the gypsy moth pheromone.     

Regulation of pheromone inhibition in mated females of Choristoneura fumiferana and C. rosaceana

In the spruce budworm, Choristoneura fumiferana, and the obliquebanded leafroller, C. rosaceana, mating significantly depressed pheromone production after 24 h. On subsequent days, the pheromone titre increased slightly in C. fumiferana, but not in C. rosaceana. No pheromonostatic activity was associated with male accessory sex gland (ASG) extracts, 20-hydroxy-ecdysone or hemolymph taken from mated females. However, pheromone production in mated females was not suppressed when the ventral nerve cord (VNC) was transected prior to mating, indicating that an intact VNC is required to permanently switch off pheromone production after mating. As suggested for other moth species, the presence of sperm in the spermatheca probably triggers the release of a signal, via the VNC, to inhibit pheromone production. The fact that in both species the brain-suboesophageal ganglion (Br-SEG) of mated females contains pheromonotropic activity and that their pheromone glands may be stimulated by the synthetic pheromone-biosynthesis-activating-neuropeptide (PBAN) or a brain extract supports the hypothesis that the neural signal prevents the release of PBAN into the hemolymph rather than inhibiting its biosynthesis. Therefore, we speculate that following the depletion of sperm in the spermatheca, the neural signal declines and is less effective in preventing the release of PBAN, thereby stimulating the resumption of pheromone production, as seen in mated C. fumiferana females. In a previous study, mating was shown to induce a significant rise in the juvenile hormone (JH) titre of both Choristoneura female moths, suggesting that post-mating pheromone inhibition may be under hormonal regulation. However, following topical applications or injections of the juvenile hormone analogue (JHA) and JH II into virgins, the pheromone only declined significantly 48 h after treatment in C. rosaceana. This suggests that the significant rise in the hemolymph JH titre after mating in C. rosaceana females plays a role in keeping the pheromone titre consistently low throughout their reproductive life. These findings will be discussed in relation to the different life histories of the two Choristoneura species.     

Sex pheromone levels in pheromone glands and identification of the pheromone and hydrocarbons in the hemolymph of the moth Scoliopteryx libatrix L. (Lepidoptera: Noctuidae)

The hydrocarbon sex pheromone (13-methyl-Z6-heneicosene) of Scoliopteryx libatrix L. (Lepidoptera: Noctuidae) was found to reach its highest levels on pheromone glands of 3-day-old females. Pheromone levels were not different between the time of maximum calling (end of scotophase) and at the middle of photophase. Overwintering females collected in October had sex pheromone present. Decapitation did not lower the amount of pheromone present, indicating that a head factor is not involved in maintaining pheromone titers. Hemolymph also contained the pheromone, indicating that it is made by oenocytes and transported to the sex pheromone gland. Longer chain length hydrocarbons were also identified from the hemolymph and on the cuticular surface. Quantitative differences in hydrocarbon profiles were found with more methyl-branched hydrocarbons found in the hemolymph than on the cuticular surface. Arch.     

Monoenyl hydrocarbons in female body wax of the yellow peach moth as synergists of aldehyde pheromone components

The non-polar components of female body wax and pheromone gland extracts of the yellow peach moth synergistically enhanced male behavioral responses from close to pheromone sources in wind tunnel tests when mixed with an aldehyde pheromone blend. When the non-polar fractions (NPFs) of female body wax were further separated by column chromatography, synergistic activities were found in the 3 and 50% ether in hexane fractions, and they additively increased male responses. The main components of the first fraction were (Z)-9-tricosene, (Z)-9-pentacosene, (Z)-9-heptacosene, (Z)-9-nonacosene and (Z)-9-hentriacontene. Only (Z)-9-heptacosene showed a significant synergistic effect in enhancing male responses, but the other components had no effect. A mixture of the five monoenyl hydrocarbons lost activity at lower doses than 5 ng. Natural ratios of these hydrocarbons in the female body wax and pheromone gland extracts were similar, but the amount of (Z)-9-heptacosene in the female body wax was significantly higher than in the pheromone gland extracts. We conclude that (Z)-9-heptacosene increases male responses to aldehyde pheromones, and unknown component(s) in the 50% ether in the hexane fraction are required for full synergistic enhancement by the NPFs of the female body wax and the pheromone gland extracts.     

Molecular mechanisms underlying sex pheromone production in the silkmoth, Bombyx mori: characterization of the molecular components involved in bombykol biosynthesis

Many species of female moths produce sex pheromones to attract conspecific males. To date, sex pheromones from more than 570 moth species have been chemically identified. Most moth species utilize Type I pheromones that consist of straight-chain compounds 10-18 carbons in length with a functional group of a primary alcohol, aldehyde, or acetate ester and usually with several double bonds. In contrast, some moth species use unsaturated hydrocarbons or hydrocarbon epoxides, classified as Type II lepidopteran pheromones, as sex pheromones. Studies over the past three decades have demonstrated that female moths usually produce sex pheromones as multi-component blends where the ratio of the individual components is precisely controlled, thus making it possible to generate species-specific pheromone blends. As for the biosynthesis of Type I pheromones, it is well established that they are de novo synthesized in the pheromone gland (PG) through modifications of fatty acid biosynthetic pathways. However, as many of the molecular components within the PG cells (i.e., enzymes, proteins, and small regulatory molecules) have not been functionally characterized, the molecular mechanisms underlying sex pheromone production in PG cells remain poorly understood. To address this, we have recently characterized some of the molecules involved in the biosynthesis of the sex pheromone bombykol in the silkmoth, Bombyx mori. Characterization of these, and other, key molecules will facilitate our understanding of the precise mechanisms underlying lepidopteran sex pheromone production.     

Novel diterpenoids and hydrocarbons in the Dufour gland of the ectoparasitoid Habrobracon hebetor (Say) (Hymenoptera: Braconidae)

Chemical constituents contained in the Dufour gland of the ectoparasitoid Habrobracon hebetor (Say) (Hymenoptera: Braconidae) were characterized. Three terpenes, beta-springene, a homo-beta-springene, and a homo-geranyllinalool constitute approximately 37% of the gland components, with the remaining 63% all being hydrocarbons. The hydrocarbons consist of a homologous series of n-alkanes (n-C21 to n-C31), a trace amount of 3-methyl C23, a homologous series of internally methyl-branched alkanes (11-methyl C23 to 13-methyl C35), one dimethylalkane (13,17-dimethyl C33), a homologous series of monoenes (C(25:1) to C(37:1)) with the double bonds located at Delta9, Delta13 and Delta15 for alkenes of carbon number 25 to 31 and at Delta13 and Delta15 for carbon numbers 33 to 37 and three homologous dienes in very low amounts with carbon numbers of 31, 32, and 33. The terpenoid and hydrocarbon composition of the Dufour gland was similar in virgin and mated females. However, in contrast to the hydrocarbons, the amount of beta-springene and homo-geranyllinalool increased significantly with time after adult emergence from the cocoon. Although many hydrocarbons in the Dufour gland are the same as those on the cuticle of this species [Howard and Baker, Arch. Insect Biochem. Physiol. 53:1-18 (2003)], substantial differences also occur. Of particular note is the chain length of alkenes and location of the double bonds: cuticular alkenes have a chain length of C23 to C29 and double bond locations at Delta5, Delta7, and Delta9, whereas the Dufour gland alkenes contains a greater range of carbon numbers and have no Delta5 or Delta7 alkenes. The Dufour gland contains only one of the long-chain dimethylalkanes found on the cuticle. Also, no terpenoids are found on the cuticle, and the Dufour gland contains none of the secondary wax esters that are major components on the cuticle. GC-MS analysis of lipids carried in the hemolymph of H. hebetor indicated that all hydrocarbons found on both the cuticle and in the Dufour gland are present, as are some of the wax esters. However, none of the terpenoids were detected in the hemolymph. This suggests that the hydrocarbons are synthesized in other tissues or cells, probably by oenocytes, and differentially partitioned between the cuticle and the Dufour gland. The terpenoids are most likely synthesized within the Dufour gland. Analysis of surface lipids from eggs laid within 18 h indicated that no diterpenoids were present. Rather, the lipids present on the eggs were n-alkanes, monomethylalkanes, alkenes, and secondary alcohol wax esters. This composition did not reflect that of the Dufour gland, hence eggs are not being coated with Dufour gland components during oviposition.     

Regulation of sex pheromone biosynthesis in two noctuid species,S. littoralis and M. brassicae,may involve both PBAN and the ventral nerve cord

In order to understand better the mechanism of regulation of pheromone production in moth species, we performed ELISA analyses to detect and follow pheromone biosynthesis activating neuropeptide-like immunoreactivity (PBAN-IR) in different tissues of the two noctuidae species, Spodoptera littoralis and Mamestra brassicae. Male S. littoralis and both male and female M. brassicae brain-subesophageal ganglion (Br-SEG), corpora cardiaca-corpora allata complex, and terminal abdominal ganglion extracts showed the presence of PBAN-IR during both the photophase and the scotophase. However, PBAN-IR was found only in scotophase in female hemolymph. Analysis of extracts of Br-SEG, terminal abdominal ganglion, and hemolymph after HPLC fractionation showed that the most immunoreactive fraction in all the extracts exhibited the same retention time as Hez-PBAN, suggesting that similar PBAN-like material is present in all these tissues. In vivo studies demonstrated that severing the ventral nerve cord in M. brassicae anterior to the terminal abdominal ganglion impaired normal sex pheromone production by third-scotophase females, as was previously shown in S. littoralis. Additionally, PBAN-IR levels were lower in hemolymph samples obtained at the peak of pheromone production in both S. littoralis and M. brassicae females that had the ventral nerve cord severed compared with sham operated animals. These results, along with earlier reported data, indicate that control of pheromone production in both species may involve both PBAN (or PBAN-like peptides) and the ventral nerve cord and support the hypothesis that a neural input from the ventral nerve cord triggers the release of the pheromonotropic peptide(s) into the hemolymph, which then acts directly on the pheromone gland to stimulate pheromone biosynthesis. Arch. Insect Biochem. Physiol. 37:295–304, 1998. © 1998 Wiley-Liss, Inc.

1 We thank Germán Lázaro for insect rearing.

     

Alkenyl sex pheromone analogs in the hemolymph of an arctiid Eilema japonica and several non-arctiid moths

The majority of moth species utilize compounds derived from de novo synthesized fatty acids as their sex pheromones (type I). In contrast, species belonging to two recently diverged moth families, Arctiidae and Geometridae, utilize alkenes and their epoxides, which are derived from dietary essential fatty acids (EFAs), as their sex pheromones (type II). In the latter species, EFAs are considered to be converted into alkenes, often after chain elongation, in specialized cells called oenocytes. These alkenes are transported through the hemolymph to the pheromone gland, from which they are secreted with or without further modifications. We confirmed that the appearance of EFA-derived alkenes in the hemolymph was closely associated with the completion of pheromone gland formation in an arctiid moth Eilema japonica. Analyses of the hemolymph of several moth species utilizing type-I sex pheromones demonstrated the occurrence of (Z,Z,Z)-3,6,9-tricosatriene (T23), a typical type-II component, in the hemolymph of a noctuid Mamestra brassicae and two crambids Ostrinia furnacalis and Ostrinia scapulalis. Our results demonstrated that moths utilizing type-I pheromones have the ability to synthesize type-II sex pheromones, and suggested that recently diverged groups of moths may have secondarily exploited EFA-derived alkenes as sex pheromones.     

Behavioral responses to the alarm pheromone of the ant Camponotus obscuripes (Hymenoptera: Formicidae)

The alarm pheromone of the ant Camponotus obscuripes (Formicinae) was identified and quantified by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). Comparisons between alarm pheromone components and extracts from the major exocrine gland of this ant species revealed that the sources of its alarm pheromone are Dufour's gland and the poison gland. Most components of Dufour's gland were saturated hydrocarbons. n-Undecane comprised more than 90% of all components and in a single Dufour's gland amounted to 19 microg. n-Decane and n-pentadecane were also included in the Dufour's gland secretion. Only formic acid was detected in the poison gland, in amounts ranging from 0.049 to 0.91 microl. This ant species releases a mixture of these substances, each of which has a different volatility and function. When the ants sensed formic acid, they eluded the source of the odor; however, they aggressively approached odors of n-undecane and n-decane, which are highly volatile. In contrast, n-pentadecane, which has the lowest volatility among the identified compounds, was shown to calm the ants. The volatilities of the alarm pheromone components were closely related to their roles in alarm communication. Highly volatile components vaporized rapidly and spread widely, and induced drastic reactions among the ants. As these components became diluted, the less volatile components calmed the excited ants. How the worker ants utilize this alarm communication system for efficient deployment of their nestmates in colony defense is also discussed herein.     

Stimulation of sex pheromone production by PBAN-like substance in the pine caterpillar moth, Dendrolimus punctatus (Lepidoptera: Lasiocampidae)

Sex pheromone production in the female pine caterpillar moth, Dendrolimus punctatus is controlled by a PBAN-like substance located in the head of female moth. Pheromone titer was significantly decreased by decapitation of female moth, and restored by injection of either Hez-PBAN or head extract prepared from male or female moth. Stimulation of pheromone production by head extract followed a dose-dependent pattern from 0.5 to at least 4 head equivalent. A gland in vitro assay was used to study the relationship between gland incubation time and pheromone production as well as calcium involvement in the stimulation of pheromone production by head extract. Maximum pheromone production was occurred at 60 min after pheromone gland was incubated with two equivalents of head extracts. In vitro experiments showed that the presence of calcium in the incubation medium was necessary for stimulation of pheromone production. The calcium ionophore, A 23187, alone stimulated pheromone production. The pheromone components (Z,E)-5,7-dodecadienol and its acetate and propionate were produced in these experiments but in addition to the aldehyde, (Z,E)-5,7-dodecadienal was also found. This indicates that females are capable of producing four oxygenated functional groups. The PBAN-like substance control of the pheromone biosynthetic pathway was investigated by monitoring the incorporation of the labeled precursor into both pheromone and pheromone intermediates.     

Continuous single sensillum recording as a detection method for moth pheromone components in the effluent of a gas chromatograph

ABSTRACT. Single sensillum recordings were made from male antennal pheromone receptors of Agrotis segetum (Schiff.) (Noctuidae) and Adoxophyes orana (F.v.R.) (Tortricidae). A gas chromatograph (GC) was used to prepare and to deliver the odour stimuli. Samples of female abdominal gland extracts were injected into the column of the GC and the responses of the receptor cells to the effluent were recorded continuously. The receptor cells responded with an increase of their action potential frequency during elution of the major pheromone components. The pheromone receptors of Agrotis showed a much higher sensitivity than those of Adoxophyes. In the extract of female glands from Agrotis , compounds were detected which have not been identified in previous studies of the sex pheromone of this species. It is suggested that the combination of GC techniques with direct single sensillum recording may serve as a valuable supplement to electro-antennographic techniques.     

Purification and characterization of biliverdin-binding vitellogenin from the hemolymph of the common cutworm,Spodoptera litura

Biliverdin-binding vitellogenin (Vg) was purified from adult female hemolymph of the common cutworm, Spodoptera litura, by using gel filtration and ion exchange chromatographies. The molecular mass of the protein was 490 kDa and it was composed of two 188-kDa subunits. Three internal amino acid sequences obtained by digestion of the protein with lysylendopeptidase showed high similarity to those of Bombyx mori Vg, supporting the purified blue protein to be vitellogenin. latroscan analyses demonstrated the presence of biliverdin in Vg that occupied 2.4% of total lipid components. Among the lipids of Vg (9.5 micrograms total lipids per 100 micrograms protein), diacylglycerol was the most predominant, followed by phospholipid, hydrocarbons, and then triacylglycerol, while in biliverdin-binding proteins (BPs) purified from larval hemolymph (3.1 micrograms total lipids per 100 micrograms protein), phospholipid was the most abundant lipid followed by diacylglycerol; hydrocarbons and triacylglycerol were minor components. Vg was first detected in the hemolymph of female pupae one day before eclosion, but injection of 5 micrograms of methoprene into a 3-day-old pupa induced Vg in the hemolymph 4 days earlier than in the control. Methoprene also induced a faster decline in BP-A and BP-B titers in the hemolymph with a corresponding increase of the Vg titer. These results suggest that juvenile hormone (JH) induces not only vitellogenesis but also the uptake of these proteins by stimulating the metamorphosis of fat body during the pupal stage.     

Isolation and identification of terpenoid sex pheromone components from extracts of hemolymph of males of the Caribbean fruit fly

Extracts obtained from hemolymph of sexually mature males of the Caribbean fruit fly Anastrepha suspensa contained four biologically important terpenoid components of the sex pheromone. The four components were identified as farnesene, bisabolene, anastrephin, and epianastrepin based on their relative retention indexes from capillary gas chromatography analysis, using both apolar and polar phase columns and their chemical ionization (isobutane) mass spectra. The ratio of the components in extracts of hemolymph was the same as the ratio present in the volatile blend of pheromone released by sexually mature males during the reproductive period. Studies conducted to determine the effect of age on amounts of these components in hemolymph indicated that they increased from undetectable levels on the day of adult emergence to maximum levels on day eight. The increases in amounts of the components present in hemolymph with increasing age were correlated with increases in amounts of volatile pheromone released by males. Time of day studies showed that the amounts of these components in hemolymph followed the daily pattern of release of volatile pheromone components. Other components of the sex pheromone including ocimene, (Z)-3-nonen-1-ol, (Z,Z)-3,6-nonadien-1-ol and suspensolide were not found in extracts of hemolymph. The data suggest that the hemolymph plays a role in the transport of these pheromone components during sexual signalling. Arch. Insect Biochem. Physiol. 42:225-232, 1999. Published 1999 Wiley-Liss, Inc.     

Hormonal regulation of sex pheromone biosynthesis in the turnip moth,Agrotis segetum

Pheromone production in the female turnip moth, Agrotis segetum, is under the control of a brain factor. This factor was demonstrated to be a proteinaceous substance termed pheromone biosynthesis activating neuropeptide-like substance (PBAN-like substance). The sex pheromone of Swedish A. segetum includes (Z)-5-decenyl acetate, (Z)-7-dodecenyl acetate, and (Z)-9-tetradecenyl acetate as major components. Decapitation of a female decreased pheromone production significantly. Pheromone production was restored by injection of homogenates of either male or female brain-suboesophageal ganglion or the corpora cardiaca alone. Pheromonotropic activity was also found in homogenates of the female thoracic ganglion and abdominal ganglion that were obtained during scotophase. Injection of female brain and thoracic ganglion homogenates made from insects during the scotophase induced two and four times as much Z7-12:OAc, respectively, as injection with similar homogenates from photophase. As little as one-eighth female equivalent (FE) brain homogenate was sufficient to increase the amount of Z7-12:OAc. The effect of brain homogenate on pheromone titer reached its maximum after 30 min. The activity of the PBAN-like substance present in female brain extracts was not correlated to the age of the donor. Injection of hemolymph collected during either photophase or scotophase into decapitated females did not increase the pheromone titer. The target site of the PBAN-like substance was not the pheromone gland, and the ventral nerve cord was not involved in the transportation of the PBAN-like substance, which implies a mode of action different from what has been reported in other moths. Brain homogenates obtained during photophase from females of African A. segetum, Spodoptera littoralis, or Ostrinia nubilalis as well as synthetic Bombyx-PBAN also induced pheromone production in decapitated Swedish female A. segetum. © 1995 Wiley-Liss, Inc.     

金龟甲性信息素的化学成分及其应用

金龟甲Scarabaeoidae性信息素研究主要集中在丽金龟亚科Rutelinae和鳃金龟亚科Melolonthinae。丽金龟亚科金龟甲的性腺由臀板和腹片顶端的上皮细胞组成,其性信息素成分主要是脂肪酸衍生物;而鳃金龟亚科金龟甲的性腺可以从腹部外翻,性信息素成分主要是氨基酸衍生物和萜烯类化合物。一些存在地理或季节隔离的物种具有结构相同的性信息素成分,但手性不同。在某些种类中,性信息素成分的手性对映体可能具有行为拮抗作用。本文综述了金龟甲性信息素的化学结构与应用的新进展。     

棉铃虫和烟青虫性信息素腺体脂肪醇和乙酸酯转化的比较研究

棉铃虫Helicoverpa armigera和烟青虫H. assulta属于可同域发生的近缘种昆虫,通过产生比例相反的两种性信息素化合物——顺9-十六碳烯醛和顺11-十六碳烯醛维持种间生殖隔离。本研究应用外源不饱和脂肪醇及乙酸酯在棉铃虫和烟青虫性信息素腺体进行在体转化,利用气相色谱法分析转化产物,从酶学角度探讨了上述两近缘种昆虫性信息素腺体组分差异的形成原因。实验结果表明,两种昆虫信息素腺体表皮伯醇氧化酶对外源顺9-十六碳烯醇、顺11-十六碳烯醇和反10-十六碳烯醇无催化专一性,说明末端氧化过程对于醛类性信息素组分特定比例的形成不起作用。棉铃虫性信息素腺体组织具有较高的乙酸酯酶活性,可水解外源乙酸酯,但烟青虫性信息素腺体乙酸酯酶活性很低。这些发现对于进一步了解两种昆虫的生殖隔离机制有重要参考价值。     

Biosynthesis of the hydrocarbon components of the sex pheromone of the housefly,Musca domestica L.

Biosynthesis of hydrocarbons, including components of the sex pheromone of the housefly Musca domestica L., was investigated. In vitro studies with isolated tissues from adult flies showed that the hydrocarbon components of the pheromone were synthesized primarily by the epidermal cells in abdominal segments two to seven. The incorporation of [³H or ¹⁴C]-labelled acetate, palmitate, stearate and oleate into the saturated and unsaturated hydrocarbon components showed that (Z)-9-tricosene (muscalure) was synthesized de novo by female insects and the distribution of label was consistent with a pathway in which oleic acid was elongated and then decarboxylated. A comparison of the incorporation and distribution of labelled acetate, propionate and succinate into hydrocarbons indicated that the mono- and dimethylalkanes were formed by the substitution of a methylmalonyl-CoA for malonyl-CoA during chain elongation. The incorporation of radioactivity from [1-¹⁴C]-propionate increased dramatically in female insects two days after adult emergence, which corresponds in time to the production of methyl branched alkanes. In contrast, this substrate was not efficiently incorporated at any time into male insects.     

草地贪夜蛾三个SfruPBPs对本种及同域种劳氏粘虫性信息素及腺体组分的亲和力

[目的]测定草地贪夜蛾Spodoptera frugiperda 3个信息素结合蛋白(pheromone binding protein,PBP)(SfruPBP)对草地贪夜蛾及同域近缘种劳氏粘虫Leucania loreyi性信息素及腺体组分的结合特性,探究草地贪夜蛾这3个SfruPBPs在两种昆虫不同性信息素组分识...