References of "Lognay, Georges"
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See detailThe taste of origin in a lady beetle: do males discriminate between females based on cuticular hydrocarbons?
Legrand, Pauline; Vanderplanck, Maryse; Marko, Istvan et al

in Physiological Entomology (2019)

The Asian lady beetle Harmonia axyridis originates from Asia and has established invasive populations at a worldwide scale. Recent population genetic studies have traced their invasion routes and ... [more ▼]

The Asian lady beetle Harmonia axyridis originates from Asia and has established invasive populations at a worldwide scale. Recent population genetic studies have traced their invasion routes and demonstrated that bottlenecks in population size have reduced their genetic diversity. As a consequence, phenotypical differences were highlighted between native and invasive populations. Among phenotypical traits, cuticular hydrocarbons (CHCs) might reflect geographical origin of a lady beetle, especially because of their genetic basis. Here, we investigated whether (i) the CHC profiles qualitatively and quantitatively differ between females of H. axyridis from native and invasive populations; and (ii) males discriminate females from native and invasive populations using CHC profiles. CHCs were solvent-extracted before being quantified and identified by gas chromatography and mass spectrometry. We detected a total of 17 CHCs from female elytra including six alkanes, three polyunsaturated and eight monounsaturated alkenes. The total quantity of CHCs differed among the populations with lady beetles from Tai’an (China) displaying a higher CHCs concentration than lady beetles from Gembloux (Belgium) and from Beijing (China) populations. Multivariate analyses detected differences in CHCs qualitative profiles, with females from Tai’an being different from the two other populations. Finally, our behavioural assays showed that females originating from the native Tai’an population were less preferred by males, while females from the invasive population were mounted more often. Our behavioural assays suggest that CHCs are not involved in discrimination of mating partners based on their origin. [less ▲]

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See detailCuticular hydrocarbon composition does not allow Harmonia axyridis males to identify the mating status of sexual partners
Legrand, Pauline; Vanderplanck, Maryse; Lorge, Stéphanie ULiege et al

in Entomologia Generalis (2019), 38(3), 211-224

Males of polyandrous species have to overcome sperm competition. They should select their mate based on the reproductive status of the female to increase their own fitness. Because the sexual behavior of ... [more ▼]

Males of polyandrous species have to overcome sperm competition. They should select their mate based on the reproductive status of the female to increase their own fitness. Because the sexual behavior of lady beetles relies on semiochemicals, with cuticular hydrocarbons (CHCs) being used for mate recognition, we developed and tested two hypotheses. First, we hypothesized that the cuticular hydrocarbon profile qualitatively and quantitatively differs between virgin and mated Harmonia axyridis females, regardless of the color morph. Second, we hypothesized that males discriminate virgin and mated females, preferring copulating with virgin females, rather than previously mated ones, to avoid sperm competition and subsequently increase their fitness. CHCs were solvent-extracted before being quantified and identified by gas chromatography. We found no qualitative differences between mated and unmated females irrespective of the morph; however, quantitative differences were detected. Specifically, the CHC profiles of mated females presented higher concentrations of alkenes, including 9-pentacosene, 9-heptacosene, and 9-hentriacontene. During dual-choice behavioral assays, males equally copulated with virgin and mated females. Our results suggest that there is no CHC-based discrimination strategy in virgin males of H. axyridis between virgin and once-mated females. We discuss alternative strategies that might be used in this lady beetle species. [less ▲]

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See detailToday and tomorrow: impact of climate change on aphid biology and potential consequences on their mutualism with ants
Blanchard, Solène ULiege; Lognay, Georges ULiege; Verheggen, François ULiege et al

in Physiological Entomology (2019)

Recent studies about mutualism are considering the complexity and versatility of the relation as well as highlighting the importance of the cost/benefit balance between the two protagonists. As species ... [more ▼]

Recent studies about mutualism are considering the complexity and versatility of the relation as well as highlighting the importance of the cost/benefit balance between the two protagonists. As species interactions are highly dependent on the environment, the climate changes that are foreseen for the coming years, are expected to have significant impacts on the evolution of mutualistic interactions. Among mutualisms, the aphid-ant interaction is well documented, partly explained by the pest status of aphids. This literature review focuses on the impact of climate change (particularly atmospheric carbon dioxide concentration and temperature) on aphids’ biology and the potential consequences on their mutualistic interactions with ants. We provide an overview of the published reports that deal with the effects of temperature and carbon dioxide on aphids, for which a positive, a negative or a no-effect was highlighted. A discussion is then provided on how climatic changes can alter four major components of aphid biology that are shaping their interaction with ants: (1) aphid population growth, (2) aphid behavior and mobility, (3) honeydew production and composition, and (4) semiochemistry. At the end of the review, we discuss limits to such studies on aphid-ant mutualism as well as the information still needed to predict how climate change might impact this kind of relationship. [less ▲]

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See detailElevated CO2 concentration impact the semiochemistry of aphid honeydew without cascade effect on an aphid predator
Blanchard, Solène ULiege; Boullis, Antoine; Detrain, Claire et al

Conference (2018, July 03)

Honeydew is now considered a cornerstone of the interactions between aphids and their natural enemies. Its composition is impacted by the aphid host plant species and associated phloem sap. Bacteria ... [more ▼]

Honeydew is now considered a cornerstone of the interactions between aphids and their natural enemies. Its composition is impacted by the aphid host plant species and associated phloem sap. Bacteria activity occurring in the aphid honeydew typically results in the release of volatile organic compounds (VOCs) that are used by aphid natural enemies for prey location. Because atmospheric carbon dioxide (CO2) concentration directly impacts plants physiology, we raise the hypothesis that elevated CO2 concentrations impact the quantity of honeydew produced by aphids, as well as the diversity and quantity of honeydew VOCs, with cascade effects on the foraging behavior of aphid natural enemies. Using solid-phase microextraction, we quantified the VOCs emitted by honeydew from pea aphids (Acyrthosiphon pisum Harris) reared either under 450 ± 50 ppm of CO2 (aCO2) or 800 ± 50 ppm of CO2 (eCO2). While the total amount of honeydew (honeydew release by 190 ± 50 individus in both conditions) is not impacted by the CO2 concentration, we found qualitative and quantitative differences in the semiochemistry of aphid honeydew between CO2 conditions. Three VOCs were not found in the honeydew of eCO2 aphids: 3-methyl-2-buten-1-ol, 2-methyl-1-butanol and isobutanol. However, no difference was observed in the searching and oviposition behavior of hoverfly (Episyrphus balteatus De Geer) females exposed to infested plants reared under both CO2 conditions, in a dual choice bioassay. The present work focuses on one particular aspect of atmospheric changes and should be extended to other abiotic parameters, such as temperature. [less ▲]

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See detailImbrasia obscura, an Edible Caterpillar of Tropical Africa: Chemical Composition and Nutritional Value
Mabossy-Mobouna, Germain; Malaisse, François ULiege; Richel, Aurore ULiege et al

in TROPICULTURA (2018), Vol. 36, N° 4

The consumption of Imbrasia obscura (Butler, 1878) has been quoted in a dozen books and papers in five different countries, namely Cameroon, Central African Republic, Congo Republic, Democratic Republic ... [more ▼]

The consumption of Imbrasia obscura (Butler, 1878) has been quoted in a dozen books and papers in five different countries, namely Cameroon, Central African Republic, Congo Republic, Democratic Republic of Congo and Angola. This study presents, for the first time, information concerning two unknown subjects, the chemical composition and the nutritional value of the species. The chemical composition shows that it is a good source of proteins and lipids with the presence of five essential amino-acids (threonine, tyrosine + phenylalanine, histidine and tryptophan) and important amounts of essential fatty acids. The mineral elements such as calcium, phosphorus, magnesium and potassium are also present in good amounts. There is little sodium for which human consumption is frequently excessive. The very high proportion of alpha-linoleic acid contributes very significantly to the low ω-6/ω-3 ratio. Consequently, this caterpillar is a food that may be recommended for human consumption. Farming this species could be encouraged because of its high nutritional value and its good commercial potential especially in areas where malnutrition is common. [less ▲]

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See detailImpact of carbon dioxide concentration on the plant-aphid-natural enemies relationship
Blanchard, Solène ULiege; Detrain, Claire; Lognay, Georges ULiege et al

Conference (2018, May 22)

While the impact of climate change on plant or insect communities has been receiving increasing attention during the last decade, plant-insect interactions under a changing environment remain to be ... [more ▼]

While the impact of climate change on plant or insect communities has been receiving increasing attention during the last decade, plant-insect interactions under a changing environment remain to be studied. These interactions are of importance as regard to the economically dimension of some crop plants and the associated species of insect pests. Insect-plant interactions are mediated by plant secondary metabolites, including volatile organic compounds (VOCs). Modifications in greenhouse gases concentrations, as predicted for 2100, could alter these chemically mediated interactions. Here, we raise the hypothesis that a raise of carbon dioxide concentration (beyond 700 ppm) affects the volatile emission of Broad bean plants, with a cascade impact on insect pests and its natural enemies. For this purpose, an experiment was made to determine the impact of CO2 concentration on aphid choice for their host plant. Choice tests were made on winged aphids between two plants grown under two CO2 concentrations. Differences were found in the choice made by the aphids. We decided then to generate odour samplings on Vicia faba plants reared under the same CO2 concentrations, hypothesizing that differences in plant semiochemicals may induce preferences for aphids. No differences were found when identifying the volatile organic compounds. Because atmospheric carbon dioxide (CO2) concentration directly impacts plants physiology, we raise the hypothesis that elevated CO2 concentrations impact the quantity of honeydew produced by aphids, as well as the diversity and quantity of honeydew VOCs, with cascade effects on the foraging behavior of aphid natural enemies. Using solid-phase microextraction, we quantified the VOCs emitted by honeydew from pea aphids (Acyrthosiphon pisum Harris) reared either under 450 ± 50 ppm of CO2 (aCO2) or 800 ± 50 ppm of CO2 (eCO2). While the total amount of honeydew (honeydew release by 190 ± 50 individus in both conditions) is not impacted by the CO2 concentration, we found qualitative and quantitative differences in the semiochemistry of aphid honeydew between CO2 conditions. Three VOCs were not found in the honeydew of eCO2 aphids: 3-methyl-2-buten-1-ol, 2-methyl-1-butanol and isobutanol. However, no difference was observed in the searching and oviposition behavior of hoverfly (Episyrphus balteatus De Geer) females exposed to infested plants reared under both CO2 conditions, in a dual choice bioassay. [less ▲]

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See detailActivité antimicrobienne de l'huile essentielle de Thymus fontanesii
Sid Ali, Lamia; Brada, Moussa; Harhour, Aicha et al

Poster (2018, May 03)

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See detailActivité antimicrobienne des huiles essentielles du juniperus pheonicea
Harhour, Aicha; Brada, Moussa; Fauconnier, Marie-Laure ULiege et al

Scientific conference (2018, May)

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See detailContribution à l'étude de la composition chimique et de l'activité antimicrobienne des huiles essentielles du juniperus oxycedrus
Harhour, Aicha; Brada, Moussa; Fauconnier, Marie-Laure ULiege et al

Scientific conference (2018, May)

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See detailChemical composition and antioxidant activity of Thymus fontanesii essential oil from Algeria
Sidali, Lamia; Brada, Moussa; Fauconnier, Marie-Laure ULiege et al

in Natural Products Journal (2018)

Background: Thymus fontanesii is one of the importance Algerian plant, used traditionally to treat the cough and cold. In addition, it may help to protect the people against lipid peroxidation and ... [more ▼]

Background: Thymus fontanesii is one of the importance Algerian plant, used traditionally to treat the cough and cold. In addition, it may help to protect the people against lipid peroxidation and oxidative stress and can be used as an antioxidant agent for the preservation of processed food. Objective: The aim of this study was to determine the chemical composition of Algerian Thymus fontanesii essential oil and to test its antioxidant activity. Method: The oil was extracted by electromagnetic induction (EMI) heating assisted extraction and by hydrodistillation, and was analysed by gas chromatography with flame ionization detector (GC/FID) and gas chromatography/mass spectrometry (GC/MS). The antioxidant activity was evaluated by three assays mainly: DPPH assay, reducing power and β-carotene/linoleic acid. Results: The yield of the essential oil was varied from 2.1 ± 0.3 to 3.1 ± 0.1% (w/w), and from 1.8 ± 0.01 to 2.6 ± 0.02% (w/w), for the electromagnetic induction heating assisted extraction and hydrodistillation, respectively. Twenty seven components were identified representing 95.6 - 99.9% of the oil. Carvacrol (54.7 ± 1.2 - 63.9 ± 1.9%) was the major compound followed by p-cymene (9.2 ± 1.2 - 17.5 ± 1.2%) and γ-terpinene (8.8 ± 0.9 - 14.9 ± 0.8%). The Thymus fontanesii essential oil was found as a significant antioxidant with IC50 values were ranging from 57.3 ± 1.4 to 236.7 ± 1.4 µg/mL, which were higher than that of butylated hydroxyl toluene (BHT) choosing as reference (9.1 ± 1.2 to 67.8 ± 0.1 µg/mL). [less ▲]

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See detailImproving the Monitoring of the Walnut Husk Fly (Diptera: Tephritidae) Using Male-Produced Lactones
Sarles, Landry ULiege; Fassotte, Bérénice ULiege; Boullis, Antoine et al

in Journal of Economic Entomology (2018), 111(5), 2032-2037

It is important to monitor fruit flies (Diptera: Tephritidae) efficiently to implement sustainable means of control. Attractants are often used to increase the efficiency of sticky traps deployed in ... [more ▼]

It is important to monitor fruit flies (Diptera: Tephritidae) efficiently to implement sustainable means of control. Attractants are often used to increase the efficiency of sticky traps deployed in orchards to monitor Lepidopterans, but remains to be developed to monitor fruit flies. Rhagoletis completa Cresson (Diptera: Tephritidae) is an invasive species in the walnut orchards of Europe, and is commonly monitored with yellow sticky traps. In this study, we collected the volatile compounds released by male and female R. completa, and identified two lactones released exclusively by males. We then formulated both lactones in long-lasting volatile dispensers, and we quantified their release rate over a 26-d period. Finally, during the entire period when female flies are present in the field, we compared the efficiency of the conventional monitoring method using unbaited yellow sticky traps with yellow sticky traps associated with a dispenser releasing both male-produced lactones. These assays were conducted in 54 walnut orchards in France, in 2017. The number of fruit flies caught with sticky traps associated with lactones dispensers was increased by up to 10 times each week. Lactone-baited traps also allowed earlier detection in the season. These field results are promising for R. completa monitoring. A complete chiral identification of these lactones should be performed along with a clarification of their role in the sexual communication of R. completa. [less ▲]

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See detailProbiotics as a Sources of Aromas in Functionnal Food: Selected Examples and Analytical Methodology (chap.5)
Kenne Kemene, Thierry ULiege; Lognay, Georges ULiege; Fauconnier, Marie-Laure ULiege

in Razafindralambo, Hary (Ed.) Trends in Probiotic Applications (2018)

Probiotics play an important role in functional foods by generating natural aromas that are fundamental for the acceptability of such products by consumers. Selected strains are added to conventional ... [more ▼]

Probiotics play an important role in functional foods by generating natural aromas that are fundamental for the acceptability of such products by consumers. Selected strains are added to conventional functional foods, not just for health properties but also for their capability to improve flavor and overall taste. Beyond their applications to functional dairy products, the use of microorganisms for the aroma in-situ generation is now expanded to meat and plant-based products. However, aromas produced by probiotics are often complex and all odor compounds are not always suitable to all foodstuff types. Therefore, it is also valuable to overview, in the present chapter, the specific analytical methodology currently used for characterizing and selecting interesting aroma compounds. [less ▲]

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See detailChemical Composition and Antioxidant Activity of Algerian Juniperus Phoenicea Essential Oil
Harhour, Aicha ULiege; Brada, Moussa; Fauconnier, Marie-Laure ULiege et al

in Natural Product Sciences (2018), 24(2), 125-131

Berries and branches essential oil of Juniperus phoenicea were obtained by electromagnetic induction heating assisted extraction and by hydrodistillation with a yield varied from (1.2 ± 0.3 to 2.4 ± 0.7 ... [more ▼]

Berries and branches essential oil of Juniperus phoenicea were obtained by electromagnetic induction heating assisted extraction and by hydrodistillation with a yield varied from (1.2 ± 0.3 to 2.4 ± 0.7%) and from (0.6 ± 0.1% to 1.1 ± 0.1%), respectively. forty eight compounds were identified representing (97.2 – 99.7%) of the oil. α-Pinene (40.3 − 67.8%) and δ-3-carene (13.5 – 26.8%) were the main compounds in berries and branches essential oils. Antioxidant activity was evaluated by three means: inhibition of 2, 2-diphenyl-1-picryl hydrazyl (DPPH) free radical, reducing power and β-Carotene/linoleic acid bleaching. The antioxidant activity of essential oils showed IC50 ranging from 67.6 ± 1.02 μg/mL to 131.5 ± 0.8 μg/mL for berries and from 98 ± 1.25 μg/mL to 166.8 ± 0.29 μg/mL for the branches. Berries oil show more potent antioxidant activity compared to branches. This result is supported by the three methods investigated in this work. [less ▲]

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See detailEnzymatic Inter-Esterification of Binary Blends Containing Irvingia gabonensis Seed Fat to Produce Cocoa Butter Substitute
Yamoneka, J.; Malumba, P.; Lognay, Georges ULiege et al

in European Journal of Lipid Science and Technology (2018), (1700423), 1-9

In order to investigate Irvingia gabonensis seed fat (IGF) as a potential cocoa butter alternative (CBA), its melting behavior is first compared to that of cocoa butter (CB). It is then modified by ... [more ▼]

In order to investigate Irvingia gabonensis seed fat (IGF) as a potential cocoa butter alternative (CBA), its melting behavior is first compared to that of cocoa butter (CB). It is then modified by blending 90% of this fat with 10% of a liquid oil either rapeseed oil (RO) or groundnut oil (GO) or palm super olein (PSO) or Dacryodes edulis pulp oil (DPO). Those blends are then enzymatically interesterified in order to improve their melting profiles. The binary blend that shows a similar profile with CB and palm kernel stearin (PKS) is chosen as the best potential new speciality fat. Compatibility between the new speciality fat and CB is evaluated by constructing phase diagrams from NMR and XRD data. The interesterified blends with 90% of IGF and 10% of DPO is chosen as the new speciality fat because its profiles is close to that of CB and shows similar characterics to PKS. The results indicate that the specialty fat produced from IGF and DPO could be used as CBS in confectionery industries (alone or mixed in low proportion with CB). Practical Applications: Fractionnated and/or hydrogenated lauric fats are frequently used by confectionery industries to substitute CB. Results from this study demonstrate that an interesterified blend made of 90% IGF and 10% of DPO can be used also as CBS. The use of these two tropical oils (Irvingia gabonensis seeds fat and Dacryodes edulis pulp oil) as new sources of CBS constitutes a promizing way for their valorization at an industrial scale. Irvingia gabonensis seed fat (IGF) is a naturel lauric fat source with a high quantity of lauric acid (≈37%). Its melting profile, which is similar to cocoa butter (CB), is too high for a direct use in its native state in confectionery application. When IGF is blend to Dacryodes edulis pulp oil and after enzymatically interesterified, its profile is close to that of CB. This result indicated that the interesterified blend can be used as cocoa butter subtitute in confectionery industries (alone or mixed in low proportion with CB). © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. [less ▲]

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See detailChemical composition of essential oils and floral waters of Ocimumbasilicum L. from Dakar and Kaolack regions, Senegal
Diop, Serigne Mbacké; Diop, Michel Bakar; Talla Gueye, Momar et al

in Journal of Essential Oil-Bearing Plants (2018), 21(2), 540-547

The chemical composition of essential oils and floral waters obtained by steam distillation from both fresh and dried plants of Ocimum basilicum L. from Dakar and Kaolack regions, Senegal were studied by ... [more ▼]

The chemical composition of essential oils and floral waters obtained by steam distillation from both fresh and dried plants of Ocimum basilicum L. from Dakar and Kaolack regions, Senegal were studied by GC and GC-MS. The main constituents identified in the oils were estragole and linalool. Estragole represented 73.3 and 70.2% (Dakar); 79.0 and 75.2% (Kaolack) and linalool constituted 12.8 and 11.7% (Dakar); 11.5 and 12.9% (Kaolack) in the oils from fresh and dried plants of O. basilicum, respectively. The most representative compounds identified in the floral waters was linalool. It was 50.5 and 51.3% in Dakar and was followed by camphor (15.4 and 17.0%), estragole (14.9 and 12.1%) and 1,8-cineole (5.9 and 6.4%). In the floral waters from Kaolack, linalool constituted 57.9 and 56.6%. Other representative components were estragole (10.0 and 9.1%), 1,8-cineole (5.9 and 6.4%), geraniol (5.2 and 5.1%) and camphor (4.1 and 4.1%) in the floral waters from fresh and dried plants from Kaolack, respectively. This study showed that both essential oils and floral waters of O. basilicum from Dakar and Kaolack are characterized by the same constituents. However, oils and floral waters differ by their contents in estragole and linalool. [less ▲]

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See detailEffet of drying methods on the chemical composition of essential oils of Xylopia aethiopicafruits (Dunal) A. Richard (Annonaceae) from southern Senegal
Thiam, Abdoulaye ULiege; Guèye, Momar Talla; Ndiyae, Ibrahima et al

in American Journal of Essential Oils and Natural Products (2018), 6(1), 25-30

The objective of this work is to study the variability of the chemical composition of essential oils of fruits of Xylopia aethiopica from southern Senegal. Essential oils were obtained by steam ... [more ▼]

The objective of this work is to study the variability of the chemical composition of essential oils of fruits of Xylopia aethiopica from southern Senegal. Essential oils were obtained by steam distillation on the fresh (F), shade-dried (DSh) and sun-dried (DS) fruits of Xylopia aethiopica. Analyzes of these essential oils carried out by GC/FID and GC/MS revealed three major compounds: β-pinene, 1,8-cineole and α-pinene in variable proportions. β-Pinene was identified for 29.9% (F), 15.1 to 31.2% (DSh) and 27.0 to 30.7% (SS), 1,8-cineole represented 14.7% (F), 14.5 to 15.1% (DSh) and 17.4 to 21.2% (SS) and α-pinene constituted 10.0% (F) 3.7 to 11,0% (DSh) and 6.6 to 10.0% (DS). [less ▲]

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