1.Identification of Cattle-Derived Volatiles that Modulate the Behavioral Response of the Biting Midge Culicoides nubeculosus.
Isberg E1, Bray DP1, Birgersson G1, Hillbur Y1,2, Ignell R3. J Chem Ecol. 2016 Jan;42(1):24-32. doi: 10.1007/s10886-015-0663-x. Epub 2015 Dec 21.
Identification of host-derived volatiles is an important step towards the development of novel surveillance and control tools for Culicoides biting midges. In this study, we identified compounds from headspace collections of cattle hair and urine that modulate the behavioral response of Culicoides nubeculosus, a research model species with a similar host-range as the vectors of Bluetongue disease and Schmallenberg disease in Europe. Combined gas chromatography and electroantennographic detection (GC-EAD) analysis revealed 23 bioactive compounds, of which 17, together with octanal, were evaluated in a two-choice behavioral assay in the presence of CO2. Decanal, 2-phenylethanal, 1-octen-3-ol, 2-ethylhexanol, 3-methylindole, phenol, and 3-ethylphenol elicited attraction of host seeking C. nubeculosus, whereas heptanal, octanal, nonanal, 3-propylphenol, and 4-propylphenol inhibited the insects' attraction to CO2, when compared to CO2 alone. 6-Methyl-5-hepten-2-one, 3-methylphenol, 4-methylphenol, and 4-ethylphenol elicited both attraction and inhibition.
2.Acquired Smell? Mature Females of the Common Green Bottle Fly Shift Semiochemical Preferences from Feces Feeding Sites to Carrion Oviposition Sites.
Brodie BS1, Babcock T2, Gries R2, Benn A2, Gries G2. J Chem Ecol. 2016 Jan;42(1):40-50. doi: 10.1007/s10886-015-0658-7. Epub 2015 Dec 4.
We investigated foraging decisions by adult females of the common green bottle fly, Lucilia sericata, in accordance with their physiological state. When we gave female flies a choice between visually occluded, fresh canine feces (feeding site) and a CO2-euthanized rat (carrion oviposition site), 3-d-old "protein-starved" females responded equally well to feces and carrion, whereas protein-fed gravid females with mature oocytes responded only to carrion, indicating resource preferences based on a fly's physiological state. Dimethyl trisulfide (DMTS) is known to attract gravid L. sericata females to carrion. Therefore, we analyzed headspace from canine feces by gas chromatographic-electroantennographic detection (GC-EAD) and GC/mass spectrometry. In bioassays, of the 17 fecal odorants that elicited GC-EAD responses from fly antennae, a blend of indole and one or more of the alcohols phenol, m-/p-cresol and 1-octen-3-ol proved as attractive to flies as canine feces.
3.A powerful approach to explore the potential of medicinal plants as a natural source of odor and antioxidant compounds.
Perestrelo R1, Silva CL1, Rodrigues F1, Caldeira M1, Câmara JS2. J Food Sci Technol. 2016 Jan;53(1):132-44. doi: 10.1007/s13197-015-2022-x. Epub 2015 Sep 11.
In this study an efficient and reliable method based on dynamic headspace solid-phase microextraction (HS-SPME) followed by gas chromatography-mass spectrometry (GC-qMS), was developed to establish the volatile metabolomic pattern of Thymus vulgaris L., Rosmarinus officinalis L. and Ruta chalepensis L. medicinal plants. The HS-SPME influencing parameters were investigated and the results indicated that the best extraction capability, was obtained using DVB/CAR/PDMS coating fiber at 40 °C for 45 min. Under optimal conditions, a total of 99 volatile metabolites were identified, including 53 terpenoids, 19 carbonyl compounds, 7 esters, 6 alcohols, among others. The main volatile metabolites identified in T. vulgaris include thymol (67 %), 3-octanone (9 %) and 1-octen-3-ol (7 %), while in R. officinalis the most dominant volatiles were eucalyptol (40 %), 2-decanone (20 %) and bornyl acetate (10 %). 2-Undecanone (53 %), (E)-2-octenal (28 %) and 2-nonanone (10 %) were the most relevant volatile metabolites identified in R.
4.Leucas aspera (Willd.) Link Essential Oil from India: β-Caryophyllene and 1-Octen-3-ol Chemotypes.
Joshi RK1. J Chromatogr Sci. 2016 Mar;54(3):295-8. doi: 10.1093/chromsci/bmv173. Epub 2015 Nov 29.
Leucas aspera (Willd.) Link (Lamiaceae) is an annual, branched herb used in traditional medicine as an antipyretic and insecticide. The hydro-distilled essential oil was obtained from the aerial parts of L. aspera growing wild in North West Karnataka region of India and analyzed by gas chromatography equipped with flame ionization detector and gas chromatography coupled with mass spectrometry. Forty-three compounds were identified, representing 98.1% of the total oil. The main constituents were identified as β-caryophyllene (34.2%), 1-octen-3-ol (14.8%), α-humulene (6.3%), α-pinene (5.8%), epi-α-bisabolol (4.6%) and limonene (4.5%). The oil was found to be rich in sesquiterpene hydrocarbons (47.7%), followed by others (long chain hydrocarbons (LCH), oxygenated LCH and phenyl derivative constituents) (20.2%), monoterpene hydrocarbons (14.8%), oxygenated sesquiterpenes (14.8%) and oxygenated monoterpenes (0.6%) type compounds.