Electrophysiological identification of 4 macrocyclic lactones as female-specific volatiles of the agarwood tree defoliator Heortia vitessoides (Lepidoptera: Crambidae).

We report the first identification of a sex pheromone in a heliozelid moth, Holocacista capensis van Nieukerken & Geertsema. This leafminer recently infested grapevine in South Africa. Compared to solvent extraction of pheromone glands, solid phase microextraction (SPME) proved to be highly effective for collection of the pheromone from calling females. The volatiles collected by SPME were analyzed by gas chromatography with electroantennographic detection (GC/EAD). Three compounds eliciting electrophysiological activity from the male antenna were identified as (Z)-5-tetradecenal, (Z)-7-tetradecenal, and (Z)-9-hexadecenal by coupled gas chromatography–mass spectrometry (GC/MS). GC/MS analysis of dimethyldisulphide (DMDS) derivatives of fatty acyl moieties in pheromone gland extracts confirmed the presence of the corresponding putative pheromone precursors with double bonds in the same position and with Z geometry. Field trapping experiments in a South African vineyard confirmed that both (Z)-5-tetradecenal and (Z)-7-tetradecenal are essential for the attraction of male H. capensis, whereas addition of (Z)-9-hexadecenal to the blend did not affect the attractiveness. The composition of the pheromone is discussed in relation to the phylogeny of this family of moths.

The fall armyworm Spodoptera frugiperda is a worldwide serious agricultural pest, and recently invaded South China. Sex pheromone can be employed to monitor its population dynamics accurately in the field. However, the pheromone components previously reported by testing different geographic populations and strains are not consistent. On the basis of confirming that the S. frugiperda population from Yunnan Province belonged to the corn strain, we analyzed the potential sex pheromone components in the pheromone gland extracts of females using gas chromatography coupled with electroantennographic detection (GC-EAD), gas chromatography coupled with mass spectrometry (GC-MS) and electroantennography (EAG). The results show that (Z)-9-tetradecenal acetate (Z9-14:Ac), (Z)-11-hexadecenyl acetate (Z11-16:Ac), (Z)-7-dodecenyl acetate (Z7-12:Ac) or (E)-7-dodecenyl acetate (E7-12:Ac) with a ratio of 100 : 15.8 : 3.9 induced EAD responses to varying degrees: Z9-14:Ac elicited a strong EAD response, Z7-12:Ac or E7-12:Ac elicited a small but clear EAD response, while Z11-16:Ac elicited a weak EAD response. Further single sensillum recording (SSR) showed that Z9-14:Ac and Z7-12:Ac induced dose-dependent activities in two types (A and B) of sensilla in male antennae, respectively, while the sensilla in response to E7-12:Ac and Z11-16:Ac was not recorded. Finally, wind tunnel tests reveal that Z9-14:Ac and Z7-12:Ac are two principal sex pheromone components of the tested population.

Ophrys flowers mimic sex pheromones of attractive females of their pollinators and attract males, which attempt to copulate with the flower and thereby pollinate it. Virgin females and orchid flowers are known to use the same chemical compounds in order to attract males. The composition of the sex pheromone and its floral analogue, however, vary between pollinator genera. Wasp-pollinated Ophrys species attract their pollinators by using polar hydroxy acids, whereas Andrena-pollinated species use a mixture of non-polar hydrocarbons. The phylogeny of Ophrys shows that its evolution was marked by episodes of rapid diversification coinciding with shifts to different pollinator groups: from wasps to Eucera and consequently to Andrena and other bees. To gain further insights, we studied pollinator attraction in O. leochroma in the context of intra- and inter-generic pollinator shifts, radiation, and diversification in the genus Ophrys. Our model species, O. leochroma, is pollinated by Eucera kullenbergi males and lies in the phylogeny between the wasp and Andrena-pollinated species; therefore, it is a remarkable point to understand pollinator shifts. We collected surface extracts of attractive E. kullenbergi females and labellum extracts of O. leochroma and analyzed them by using gas chromatography with electroantennographic detection (GC-EAD) and gas chromatography coupled with mass spectrometry (GC-MS). We also performed field bioassays. Our results show that O. leochroma mimics the sex pheromone of its pollinator's female by using aldehydes, alcohols, fatty acids, and non-polar compounds (hydrocarbons). Therefore, in terms of the chemistry of pollinator attraction, Eucera-pollinated Ophrys species might represent an intermediate stage between wasp- and Andrena-pollinated orchid species.

Agroecus griseus is a serious corn pest in Brazil. Contents of the dorsal abdominal glands (DAGs) in nymphs, and the metathoracic gland (MTG) in adults of this species were characterized and quantified. Compounds found were similar to those of other Pentatomidae species and included aliphatic hydrocarbons, aldehydes, oxo-alkenals, and esters. However, two compounds were found in the MTG that have not been described previously for this family. Mass spectrometry, infrared spectroscopy, and gas chromatographic analysis using coinjection with authentic standards confirmed the identities of the compounds as enantiopure (S)-2-methylbutyl acetate and 3-methyl-2-butenyl acetate. The five nymphal instars showed significantly different ratios of components, mainly between those of the first and later instars. No significant differences were detected in MTG contents between sexes. Gas chromatography (GC) analysis of aeration extracts of males and females showed the presence of a compound released exclusively by males. Gas chromatography - electroantennographic detection (GC-EAD) assays indicated that the male-specific compound is bioactive in females, suggesting the presence of an attractant pheromone. The mass spectrum and infrared data for this compound matched with methyl 2,6,10-trimethyltridecanoate, a sex pheromone component previously detected in the stink bugs, Euschistus heros and E. obscurus. The synthetic standard coeluted with the natural pheromone on two different GC stationary phases, confirming the proposed structure. Y-tube olfactometer assays showed that the synthetic standard was strongly attractive to females, and GC-EAD tests produced responses with antennae from females similar to those of the natural pheromone.

Male Colletes cunicularius bees pollinate the orchid, Ophrys exaltata, after being sexually deceived by the orchid's odor-mimicry of the female bee's sex pheromone. We detected biologically active volatiles of C. cunicularius by using gas chromatographic-electroantennographic detection (GC-EAD) with simultaneous flame ionization detection. After identification of the target compounds by coupled gas chromatography mass spectrometry (GC-MS), we performed behavioral tests using synthetic blends of the active components. We detected 22 EAD active compounds in cuticular extracts of C. cunicularius females. Blends of straight chain, odd-numbered alkanes and (Z)-7-alkenes with 21-29 carbon atoms constituted the major biologically active compounds. Alkenes were the key compounds releasing mating behavior, especially those with (Z)-7 unsaturation. Comparison of patterns of bee volatiles with those of O. exaltata subsp. archipelagi revealed that all EAD-active compounds were also found in extracts of orchid labella. Previous studies of the mating behavior in C. cunicularius showed linalool to be an important attractant for patrolling males. We confirmed this with synthetic linalool but found that it rarely elicited copulatory behavior, in accordance with previous studies. A blend of active cuticular compounds with linalool elicited both attraction and copulation behavior in patrolling males. Thus, linalool appears to function as a long-range attractant, whereas cuticular hydrocarbons are necessary for inducing short-range mating behavior.

The spruce seed moth, Cydia strobilella L., is a serious pest on cones of spruce (Picea spp.) in the Holarctic region. Previous studies from different parts of its area of distribution have reported conflicting results on the composition of its sex pheromone. By gas chromatography with electroantennographic detection, coupled gas chromatography-mass spectrometry, a Y-tube olfactometer bioassay, and field trials, the sex pheromone of Swedish populations of the species was identified as (8E,10E)-dodecadienyl acetate and (8E,10Z)-dodecadienyl acetate. About 0.5 pg of each pheromone component was extracted per female. The most attractive blend of EE- and EZ-isomers was about 6:4, respectively, and 0.3 microg of the blend per rubber septum was the most attractive dosage for field trapping. Monounsaturated components previously reported as sex pheromone components/attractants for C. strobilella, (E)-8-dodecenyl acetate in Canadian populations and (Z)-8-dodecenol in Polish and Dutch populations, did not attract any C. strobilella in this study. Large numbers of C. jungiella Clerck were trapped by using (8E,10Z)-dodecadienyl acetate alone, whereas (Z)-8-dodecenol attracted Pammene splendidulana Guenée and P. rhediella Clerck.

Identification of perfumery residues contained in glass objects from Parthian to early Islamic period with gas-chromatography coupled with mass spectroscopy

Chemical, electrophysiological, and field trapping experiments were carried out to identify the female-produced sex pheromone of the asparagus moth, Parahypopta caestrum, a very serious pests of asparagus cultivations in southern Europe. Gas chromatography coupled with mass spectrometry and electroantennogram detection (GC-MS-EAD) analysis of hexane and solid-phase microextraction (SPME) extracts of sex pheromone glands of calling females consistently detected four compounds eliciting EAG responses in male moth antennae. According to their GC retention times, mass spectra, and comparative EAG analyses with reference standards, these EAD-active compounds were identified as (Z)-9-tetradecenol (Z9-14:OH), (Z)-5-tetradecenyl acetate (Z5-14:Ac), (Z)-7-tetradecenyl acetate (Z7-14:Ac), and (Z)-9-tetradecenyl acetate (Z9-14:Ac), respectively. In the SPME extracts from the head-space of individual abdominal tips, Z9-14:Ac, Z5-14:Ac, Z7-14:Ac, and Z9:14 OH were detected in the ratio of 82:9:5:4. In EAG dose-response experiments, Z9-14:Ac was the strongest antennal stimulant at different doses tested. In field trapping experiments, Z9-14:Ac, Z7-14:Ac, and Z5-14:Ac proven to be essential for male attraction and a their 85:5:10 blend loaded onto green rubber septum dispensers was significantly more effective than single-, two-, and any other three-component blend of these compounds. The addition of Z9-14:OH to the optimal blend resulted in a significant reduction of male catches. The attractive blend here identified allowed for an effective and accurate monitoring of P. caestrum flight activity in southern Italy.

The importance of carcass volatiles as attractants for the hide beetle Dermestes maculatus (De Geer)

The ability to determine combustion and thermal decomposition (pyrolysis) products at trace concentrations can lead to important information on catalytic pathways, the degradation process itself, and structural (fingerprint) information on the parent molecule(s), among others. Gas chromatography coupled with mass spectrometry (GC/MS) is well suited to separate and identify the volatile molecules and molecular fragments generated by combustion and pyrolysis processes. Whereas, pyrolysis (conducted in an inert atmosphere) is often used as a sample introduction device directly coupled to GC/MS, combustion is generally carried out offline and its products are collected and analyzed with GC/MS, or even pyrolysis‐GC/MS. In the past few years, this powerful technique has been used to examine a variety of sample types for quite diverse applications. This chapter describes the state of the art and the progress of GC/MS for the measurement of combustion and pyrolysis products. An introduction to the technique, including the principles of GC/MS, is first provided, followed by a demonstration of the instrument's capabilities for combustion and pyrolysis research. All reports discussed herein were selected in part to demonstrate the diversity of current combustion and pyrolysis research using GC/MS. The present authors' studies with temperature‐programmed desorption in conjunction with GC/MS to characterize oxygen shuttling on the chars derived from different gaseous environment, are highlighted. Finally, the use of GC/MS in combination with isotope‐labeling techniques to reveal complex reaction pathways and mechanisms is discussed.

BackgroundIbalia leucospoides (Hymenoptera: Ibaliidae) is a larval parasitoid that has been widely introduced as a biological control agent for the invasive woodwasp,Sirex noctilio (Hymenoptera: Siricidae) in the Southern Hemisphere. In this study, the courtship behavior and identificaion of sex pheromones are described for I. leucospoides under laboratory conditions.MethodsFor courtship behavior, both sexes were observed in a wire mesh observation cylinder (75 cm length ×10 cm diameter) for 15 minutes. The female body washes were analyzed using Gas Chromatography- Electroantennographic Detection (GC-EAD). Then the EAD-active compounds were tentatively identified using GC-Mass Spectrometry (GC-MS) and examined in olfactometer assays.ResultsThe courtship behavior included rhythmic lateral movements, mounting, head-nodding cycles in males, and wing-fanning in females. GC-EAD analysis of female body washes with male antennae revealed seven compounds which elicited antennal responses, four of which are straight-chain alkanes (C23, C25, C26, and C27). The identities of these alkanes were confirmed by matching the retention times, mass spectra, and male antennal activity to those of commercially obtained chemicals. In olfactometer assays, a blend of the four straight-chain alkanes was attractive to I. leucospoides males, and there was no response to blends that lacked any of these four compounds. Female body wash was no more attractive than the four-component blend. The ratios of EAD-active components differ between hydrocarbon profiles from males and females.ConclusionThis study is the first investigation of cuticular hydrocarbons in the family Ibaliidae. It provides evidence that the ubiquitous alkanes (C23, C25, C26, and C27) in sex-specific ratios attract I. leucospoides males.

Female moths release sex pheromone to attract mates. In most species, sex pheromone is produced in, and released from, a specific gland. In a previous study, we used empirical data and compartmental modeling to account for the major pheromone gland processes of female Chloridea virescens: synthesis, storage, catabolism and release; we found that females released little (20-30%) of their pheromone, with most catabolized. The recent publication of a new pheromone collection method led us to reinvestigate pheromone release and catabolism in C. virescens on the basis that our original study might have underestimated release rate (thereby overestimating catabolism) due to methodology and females not calling (releasing) continuously. Further we wished to compare pheromone storage/catabolism between calling and non-calling females. First, we observed calling intermittency of females. Then, using decapitated females, we used the new collection method, along with compartmental modeling, gland sampling and stable isotope labeling, to determine differences in pheromone release, catabolism and storage between (forced) simulated calling and non-calling females. We found, (i) intact 1 d females call intermittently; (ii) pheromone is released at a higher rate than previously determined, with simulations estimating that continuously calling females release ca. 70% of their pheromone (only 30% catabolized); (iii) extension (calling)/retraction of the ovipositor is a highly effective "on/off' mechanism for release; (iv) both calling and non-calling females store most pheromone on or near the gland surface, but calling females catabolize less pheromone; (v) females are capable of producing and releasing pheromone very rapidly. Thus, not only is the moth pheromone gland efficient, in terms of the proportion of pheromone released Vs. catabolized, but it is highly effective at shutting on/off a high flux of pheromone for release.

To obtain a detailed picture of sulfur deprivation-induced H(2) production in microalgae, metabolome analyses were performed during key time points of the anaerobic H(2) production process of Chlamydomonas reinhardtii. Analyses were performed using gas chromatography coupled to mass spectrometry (GC/MS), two-dimensional gas chromatography combined with time-of-flight mass spectrometry (GCxGC-TOFMS), lipid and starch analysis, and enzymatic determination of fermentative products. The studies were designed to provide a detailed metabolite profile of the solar Bio-H(2) production process. This work reports on the differential analysis of metabolic profiles of the high H(2)-producing strain Stm6Glc4 and the wild-type cc406 (WT) before and during the H(2) production phase. Using GCxGC-TOFMS analysis the number of detected peaks increased from 128 peaks, previously detected by GC/MS techniques, to ∼1168. More detailed analysis of the anaerobic H(2) production phase revealed remarkable differences between wild-type and mutant cells in a number of metabolic pathways. Under these physiological conditions the WT produced up to 2.6 times more fatty acids, 2.2 times more neutral lipids, and up to 4 times more fermentation products compared with Stm6Glc4. Based on these results, specific metabolic pathways involving the synthesis of fatty acids, neutral lipids, and fermentation products during anaerobiosis in C. reinhardtii have been identified as potential targets for metabolic engineering to further enhance substrate supply for the hydrogenase(s) in the chloroplast.

This chapter deals with the application of gas chromatography coupled to mass spectrometry (GC-MS) in the identification of designer drugs and problems that may arise when using it. Gas chromatography is a perfect separating technique but provides no molecular identification information about the chromatographed compound. GC-MS has become a well-established analytical technique in a large variety of forensic applications and is now a method of choice used in many working analytical procedures in forensic laboratories. Derivatization serves several important functions in the GC-MS analysis. Derivatization may also prevent the phenomenon of transesterification, which has been observed when injections of the underivatized drugs have been made with methanol used as a solvent or even spontaneously when stocked in a methanolic solution. Identification of designer drugs using GC-MS is based on mass spectra and retention times of the analyzed compounds. In order to compare the retention times between the analyses or among the instruments, retention time locking is introduced.

HPLC and GC/MS determination of 4-aminobiphenyl haemoglobin adducts in fetuses exposed to the tobacco smoke carcinogen in utero