Alexej Nikiforov

A butterfly’s chemical key to various ant forts: intersection-odour or aggregate-odour multi-host mimicry?

Deception is a crucial yet incompletely understood strategy of social parasites. In central Europe, the Mountain Alcon Blue, Maculinea rebeli, a highly endangered butterfly, parasitises several Myrmica ant species. Caterpillars gain access to host nests probably by faking the ants’ odour. We analysed gas chromatography–mass spectrometry data of body surface hydrocarbons of pre-adoption and hibernated larvae of Maculinea rebeli and of their host species Myrmica sabuleti and M. schencki. Data were ordinated by different methods, based on similarities in the relative quantities of compounds between chromatograms. The two Myrmica species exhibit species-specific profiles. The Maculinea rebeli pre-adoption larva has a complex profile that simultaneously contains species-specific substances of the two investigated host species. This evidence leads to the interpretation that, in central Europe, Maculinea rebeli is predisposed for multi-host use by the chemical signature of its pre-adoption larva. The Maculinea rebeli larva clearly does not rely on an “intersection-odour” of compounds common to all host ant species, but synthesises an “aggregate-odour” containing specific compounds of each of the investigated hosts. We term this previously unknown chemical strategy “aggregate-odour multi-host mimicry”.

Cuticular hydrocarbons of Tetramorium ants from central Europe: analysis of GC-MS data with self-organizing maps (SOM) and implications for systematics.

Cuticular hydrocarbons were extracted from workers of 63 different nests of five species of Tetramorium ants (Hymenoptera: Formicidae) from Austria, Hungary, and Spain. The GC-MS data were classified (data mining) by self-organizing maps (SOM). SOM neurons derived from primary neuron separation were subjected to hierarchical SOM (HSOM) and were grouped to neuron areas on the basis of vicinity in the hexagonal output grid. While primary neuron separation and HSOM resulted in classifications on a level more sensitive than species differences, neuron areas resulted in chemical phenotypes apparently of the order of species. These chemical phenotypes have implications for systematics: while the chemical phenotypes for T. ferox and T. moravicum correspond to morphological determination, in T. caespitum and T. impurum a total of six chemical phenotypes is found. Three hypotheses are discussed to explain this disparity between morphological and chemical classifications, including in particular the possibility of hybridization and the existence of cryptic species. Overall, the GC-MS profiles classified by SOM prove to be a practical alternative to morphological determination (T. ferox, T. moravicum) and indicate the need to revisit systematics (T. caespitum, T. impurum).

GC-FTIR and GC-MS in odour analysis of essential oils

The analysis of odour components in East Indian Sandalwood Oil (Santalum album L.) and in Patchouli Oil (Pogostemon cablin Benth.) based on GC-, GC-FTIR- and GC-MS-data resulted in the identification ofα-santalene,α-santalal,β-santalal, epi-β-santalal,α-santalol,β-santalol, (E)-β-santalol,α-bergamotol and spirosantalol in Sandalwood Oil and of (−)-patchoulol,α-guaiene,α-patchoulene, seychellene,α-bulnesene, norpatchoulenol and pogostol in Patchouli Oil as the most intense aroma compounds of these oils.

Zum Aroma von Speisepilzen

Headspace samples, steam distillates and dichloromethane extracts of the most well liked edible mushrooms (Agaricus campestris, Agaricus bisporus, Lepiota procera, Armillaria mellea, Boletus edulis and Cantharellus cibarius) were investigated by means of GC/FID, GC/FTIR/MS and a GC-sniffing technique. The aim of these analyses was the identification of constituents responsible for the typical mushroom odour of each species. To relate GC/Fouriertransform Infrarot-Detektor/MS (GC/FTIR/MS) data with olfactoric ones, the GC-sniffing technique was used. The results, especially of the headspace samples, showed that 1-octen-3-ol, a well-known mushroom aroma compound, is of basic importance for the top note of the investigated mushrooms. More than seventy constituents that additionally have an effect (qualitatively and quantitatively) on the odour impression of these species were identified. Among them especially C8-derivatives contribute in a significant way to the headspace odour of most of the samples. Carbonyls and esters (C4-C14) on the other hand play an important role (e.g. anisaldehyde inAgaricus samples) more in the steam distillate and extract samples.ZusammenfassungKopfraum-Proben, Wasserdampfdestillate und Dichlormethanextrakte der beliebtesten Speisepilze Champignon (Agaricus campestris undAgaricus bisporus), Parasol (Riesenschirmpilz,Lepiota procera), Hallimasch (Armillaria mellea), Steinpilz (Herrenpilz,Boletus edulis) und Pfifferling (Eierschwamm,Cantharellus cibarius) wurden mittels GC/FID, GC/FTIR/MS und GC-Sniffing-Technik untersucht. Ziel dieser Untersuchungen war es, die für den typischen Duft der einzelnen Pilzarten verantwortlichen Inhaltsstoffe zu identifizieren. Um Daten aus GC/FTIR/MS-Messungen mit olfactorischen Daten direkt vergleichen zu können, wurde die GC-Sniffing-Technik verwendet. Die Ergebnisse, besonders solche von Kopfraumproben, zeigten, daß 1-Octen-3-o1, ein bekannter Pilzduftstoff, von grundlegender Bedeutung für die Kopfnote der untersuchten Pilze ist. Mehr als 70 Einzelkomponenten tragen qualitativ und quantitativ zum Gesamtgeruchseindruck der einzelnen Arten bei, wobei besonders C8-Derivate in signifikanter Weise den Duft der meisten Kopfraumproben beeinflussen. Carbonylverbindungen und Ester (C4-C14) dagegen spielen eine wesentliche Rolle (z. B. Anisaldehyd in Champignonproben) vor allem in den Wasserdampfdestillations- und Extraktproben.

Headspace Analysis of Vitis vinifera (Vitaceae) Flowers

ABSTRACT Three samples (headspace, essential oil and a dichloromethane extract) of Vitis vinifera (Vitaceae) flowers (species “Gruner Veltliner”) were analyzed by GC, GC/FTIR and GC/MS to determine the volatile constituents of this odorous flower from Austrian vineyards. Although more than 30 compounds were identified by these procedures, only the sesquiterpenes valencene, α- and β-farnesene, β-bisabolene, α-humulene, β- and δ-selinene, γ-cadinene and nerolidol as well as 2-tridecanone and benzyl benzoate were considered to be important components of the aroma of the flowers of V. vinifera as determined by a GC-sniffing technique.

Die geruchsintensivsten Inhaltsstoffe des ostindischen Sandelholzöles

The most odour intensive constituents of east indian sandal wood oil are β-santalol, β-santalal and α-santalene. This has been proved by a thorough GLC-investigation in combination with the sniffing technique of seven fractions of this highly priced essential oil, which have been obtained by TLC on silica-cellulose plates with simultaneous organoleptic evaluation. Using the headspace analysis these results could be confirmed and further the distribution of the main odour components was obtained in headspace at 37° and 80°.

Quantitative determination of natural dipalmitoyl lecithin with dimyristoyl lecithin as internal standard by capillary gas-liquid chromatography

Abstract A quantitative determination of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine from dog lungs by means of the corresponding diacyl glycerol trimethylsilyl ether derivative with 1,2-dimyristoyl-sn-glycero-3-phosphocholine as internal standard was carried out by gas-liquid chromatography with glass capillary columns. The individual diacyl glycerol species were identified by using a combination of gas-liquid chromatography and mass spectrometry. In a total of 32 determinations percent deviations from the mean value between ± 2.0 and ± 4.4% were achieved. By using glass capillary columns instead of conventional columns the time required for an analysis was reduced to ca. 30% and separation was considerably improved. Thus the diacyl glycerol species from PC-32 were separated according to both the 1,2 and 1,3 positional isomerism and the degree of saturation of the acyl radicals.

Aroma von Weißweinblüten: Korrelation sensorischer Daten mit Headspace-Inhaltsstoffen

Using headspace-analysis in combination with gaschromatographic-spectroscopic methods (GC-FID and GC-FTIR-MS) as well as with the GC-sniffing-technique it was possible to correlate blossoms of 7 different vine-varieties by means of the composition of odor compounds in their headspace considering only odor-dominant sesquiterpenes and odor-assistant monoterpenes. -All investigated vineblossoms possess a mignonette-like, pleasant, floral, dusty, dry, interesting, green, fresh, intense and sweet odour and with regard to the vine-species they only differ in the intensity of single odournotes, but not in the direction of the total odour. The odour-profiles and the corresponding multivariate data analysis of these profiles showed a significant agreement with those results, which were obtained by correlations of headspace constituents. -The possibility of further connectivities with the corresponding ampelographic aspects of the investigated vine-species is also discussed.ZusammenfassungMittels Headspace-Analyse in Kombination mit gaschromatographisch-spektroskopischen Methoden (GC-FID und GC-FTIR-MS), sowie der GC-Schnüffel-Technik gelang es, Blüten verschiedener Weinsorten (sieben verschiedene Weißweinspecies) anhand der Duftstoff-Zusammensetzung bezüglich duftbestimmender Sesquiterpene und duftabrundender Monoterpene im Headspace zu korrelieren.-Alle untersuchten Weinblüten besitzen einen reseda-artigen, schönen, blumigen, staubigen, trockenen, angenehmen, interessanten, grünen, frischen, intensiven und süßen Duft wobei sich die einzelnen Blüten, je nach Weinsorte, lediglich in der Intensität der Einzeldüfte, nicht aber in der Gesamtduftrichtung unterscheiden. Die erstellten Geruchsprofile und die entsprechenden multivariaten Korrelationen dieser Profile zeigten eine weitgehende Übereinstimmung mit jenen Ergebnissen, die aus den Headspace-Inhaltsstoffkorrelationen der einzelnen Blütensorten erhalten werden konnten. -Die Möglichkeiten weiterer Zusammenhänge mit entsprechenden ampelographischen Aspekten der untersuchten Weinsorten werden diskutiert.

Volatile Constituents of the Headspace and Essential Oil of Plectranthus coleoides Marginatus (Labiatae)

ABSTRACT The headspace and essential oil of the whole plant of Plectranthus coleoides Marginatus were analyzed by GC/FID, GC/FTIR/MS and GC-sniffing techniques. The headspace was found to be rich in monoterpenes, fenchone (14.2%), bornyl acetate (9.3%), isobornyl acetate (8.2%) and β-caryophyllene (11.3%), while the essential oil comprises of additional odorous N-compounds (especially amines) as well as minor aromatic (methyl benzene derivatives) components. Totally 41 constituents were identified. Also an odor characterization of the headspace sample and the essential oil is given.

Comparison of the Effects of Betamethasone and L-Carnitine on Dipalmitoylphosphatidylcholine Content and Phosphatidylcholine Species Composition in Fetal Rat Lungs

ABSTRACT: Antepartum administration of L-carnitine to pregnant rats results in an increase of both total phospholipid (80 ± 11 mg/g dry weight (dw); mean ± SD) and dipalmitoylphosphatidylcholine (DPPC) content (7.7 ± 2.1 mg/g dw) in fetal lungs as compared to controls (72 ± 10 and 7.0 ± 2.5 mg/g dw, respectively). On the other hand, no effect of L-carnitine could be demonstrated on the DPPC portion in the total phosphatidylcholine (PC) or on the portion of palmitic acid in the PC fatty acids.Betamethasone elevated the DPPC content in fetal lungs (8.1 ± 2.0 versus 7.0 ± 2.5 mg/g dw in the controls), while total phospholipid content remained unaffected (71 ± 19 versus 72 ± 10 mg/g dw). The portion of DPPC in the PC species increased significantly (p < 0.01) from 27.6 ± 4.5 in the fetal lungs of the control group to 34.2 ± 3.3 in the lungs of the betamethasone-treated group, while the palmitic acid portion in the PC fatty acids was nearly unchanged (45.9 ± 3.2 versus 43.9 ± 2.6 in the controls). Further, after betamethasone treatment, a significant diminution (p < 0.01) of the monoenic PC 32 species (palmitoyl- palmitoleyl PC and palmitoleyl-palmitoyl-PC) and the PC 34 species (consisting primarily of palmitoyl-oleoyl- PC) could be demonstrated both in absolute and relative terms. This is in agreement with a significant reduction of the portions of palmitoleic (p < 0.01) and oleic (p < 0.05) acids in the total PC fatty acids. The findings suggest two different mechanisms of DPPC elevation in fetal rat lungs for L-carnitine and betamethasone.