Identification and quantification of VOCs emitted by the roots of barley (Hordeum vulgare cv. Quench) aged from 21 days by headspace solid-phase microextraction coupled to gas chromatography (HS-SPME GC-MS)

Poster (2012, February 10)

Growth modelling and profiling of volatile organic compounds in Barley (Hordeum distichon L.) roots

Poster (2012, February 10)

The roles played by root volatile organic compounds (VOC) remain essentially unknown. This study aims at identifying VOC contained by H. distichon roots at selected growth developmental stages. As an ... [more ▼]

The roles played by root volatile organic compounds (VOC) remain essentially unknown. This study aims at identifying VOC contained by H. distichon roots at selected growth developmental stages. As an original contribution, these were positioned on growth models calibrated for barley plants cultivated in our growth conditions. By SPME-GC/MS, a total of 110 compounds were detected and 70% of them were tentatively identified based on their mass spectra and retention time. Alcohols, aldehydes, ketones and organic acid esters accounted for 55,5% of the total number of detected VOC. Multivariate analysis revealed qualitative and quantitative changes in such profiles according to the developmental stage. In general, the VOC content was the highest when young roots just emerged from the coleorhiza. [less ▲]

Recherches de lignées aromatiques d'Abies par hybridation somatique

Report (2012)

Variations in the essential oils from ylang-ylang (Cananga odorata [Lam.] Hook f. & Thomson forma genuina) in the Western Indian Ocean islands

in Flavour and Fragrance Journal (2012), 27(5), 356-366

Ylang-ylang essential oil is an important rawmaterial for the fragrance industry. Despite its economic importance, to the best of our knowledge, no study has yet been undertaken to assess the chemical ... [more ▼]

Ylang-ylang essential oil is an important rawmaterial for the fragrance industry. Despite its economic importance, to the best of our knowledge, no study has yet been undertaken to assess the chemical polymorphism of the different production areas. This underestimated variability is an interesting source of raw material for perfumers. That is why the variation in the chemical composition of four fractions of the essential oils extracted from Cananga odorata, grown in four locations Grande Comore, Mayotte, Nossi Bé and Ambanja, was studied. A total of 119 compounds, representing 85.7–96.4%of the total essential oil composition, were identified using gas chromatography–mass spectrometry and quantified by gas chromatography with a flame ionization detector. Thirty-two compounds previously unreported in ylang-ylang essential oil were identified. The distinction between the Comoros and Madagascar groups wasmade on the basis of the chemical classes. It was possible to significantly distinguish the Grande Comore and Mayotte essential oil samples, as well as the Ambanja and Nossi Bé essential oil samples, on the basis of their main compounds. The aromatic compounds profile for the origin of each essential oil fraction was established. Regression trees were built, allowing the provenance of the essential oils prepared at the laboratory level to be easily differentiated on the basis of a limited number of major compounds. [less ▲]

Optimization and scaling up of a biotechnological synthesis of natural green leaf volatiles using Beta vulgaris hydroperoxide lyase

in Process Biochemistry (2012), 47

(Trans)esterification of mannose catalyzed by lipase B from Candida antarctica in an improved reaction medium using co-solvents and molecular sieve

in Preparative Biochemistry & Biotechnology (2012), 42(4), 348-363

Efficacy of powdered maize cobs against the maize weevil Sitophilus zeamais (Coleoptera: Curculionidae) in stored maize in Senegal

in International Journal of Tropical Insect Science (2012)

Powdered maize cobs were tested as an alternative for pesticide use in stored maize. Five doses (2, 4, 6, 8 and 10 g/250 g seed) of powdered maize cobs applied at particle sizes of 1.4 and 0.4mm diameter ... [more ▼]

Powdered maize cobs were tested as an alternative for pesticide use in stored maize. Five doses (2, 4, 6, 8 and 10 g/250 g seed) of powdered maize cobs applied at particle sizes of 1.4 and 0.4mm diameter were compared with actellic powder against Sitophilus zeamais Motschulsky for 120 days. Mortality and survival data showed that cob powders did not act as fumigant but exerted a potent inhibition of progeny on direct contact with S. zeamais adults. The particle size of powdered cobs had no effect on maize damage and losses. At doses equal to or higher than 6 g powdered maize cobs/250 g grain maize, i.e. 2.4% (w/w), damage to grain was ,5% and weight losses ,1%. The protection offered at the highest dose was comparable to the pesticide control. The use of powdered maize cobs is discussed as a natural alternative to synthetic pesticides for protection of maize against S. zeamais. [less ▲]

Role of long-chain hydrocarbons in the aggregation behaviour of Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae)

in Journal of Insect Physiology (2012)

The multicoloured Asian ladybeetles, Harmonia axyridis (Pallas), form large aggregations inside dwellings to survive cold winters, causing annoyances to householders from their number and sometimes the ... [more ▼]

The multicoloured Asian ladybeetles, Harmonia axyridis (Pallas), form large aggregations inside dwellings to survive cold winters, causing annoyances to householders from their number and sometimes the induction of allergic reactions. Migratory flight and macrosite choice of this species is well documented. H. axyridis shows a hypsotactic behaviour and a clear preference for contrasting visual elements. However, how the microsite is selected remains undocumented, although a better understanding of the implicated factors could lead to the development of new control methods for this pest. In this work, we have hypothesized that non-volatile compounds are involved in the microsite choice and the aggregation process of this beetle. Long chain hydrocarbons were identified inside aggregation sites, comprising saturated and unsaturated homologues. An aggregation bioassay was then conducted on overwintering individuals, highlighting the retention capacity of the previously cited compounds on the tested ladybeetles. Additional investigations have shown that H. axyridis males and females, originating from overwintering sites, deposit a similar blend of molecules while walking. A Y-shaped tube assay revealed that this blend is used by male and female congeners as cue, allowing individuals to orientate towards the treated side of the olfactometer. These results suggest the use of two different blends of long chain hydrocarbons by H. axyridis during its aggregative period, the first one to lead conspecifics towards aggregation sites (microsites) and the second to ensure the cohesion of the aggregation. These findings support the potential use of these blends, in association with volatiles, in the design of traps in order to control infestations of this species in dwellings. [less ▲]

Chemical composition and physicochemical characteristics of fixed oils from Algerian Nigella sativa seeds

in Chemistry of Natural Compounds (2012), 47(6), 925-931

The fatty acids, sterols, and polyphenols from the fixed oils of Nigella sativa seeds originating from four locations were determined. The seeds contained respectively 30.63–34.27% and 25.66–32.77% of ... [more ▼]

The fatty acids, sterols, and polyphenols from the fixed oils of Nigella sativa seeds originating from four locations were determined. The seeds contained respectively 30.63–34.27% and 25.66–32.77% of fixed oils using hexane and isopropyl alcohol in solvent extraction. Linoleic, oleic, and palmitic acids formed the main proportion using the two solvents, respectively: hexane 54.47–61.28%, isopropanol 56.98–67.30%; hexane 19.62–22.94%, isopropanol 18.85–21.96%, and hexane 11.17–13.60%, isopropanol 9.20–14.18%. Other minor unsaturated fatty acids were identified. Eight phytosterols were isolated and identified in the fixed oils by GC and GC/MS analysis, wherein -sitosterol was the dominating compound that inhibits the absorption of dietary cholesterol, followed by stigmasterol, campesterol, and 5-avenasterol. [less ▲]

Caractérisation des coposés volatils des huiles d'olive produites dans des coopératives de la région orientale du Maroc

in 5èmes Journées Internationales d'Etude sur les Lipides - JIEL 2011 : Graisses alimentaires, Lipides marins, Nutrition et Santé (2011, December 08)