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See detailUPLC®-MS/MS, an analytical tool for the accurate and rapid quantification of phytoestrogen metabolites in milk
Daems, Frédéric ULg; Jasselette, Christophe; Romnee, Jean-Michel et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (in press)

The term ‘phytoestrogen’ is used to define a wide variety of nonsteroidal compounds that occur naturally in many plants. When they are absorbed by cows, these polyphenolic compounds undergo ... [more ▼]

The term ‘phytoestrogen’ is used to define a wide variety of nonsteroidal compounds that occur naturally in many plants. When they are absorbed by cows, these polyphenolic compounds undergo biotransformation by specific bacteria present in the gastrointestinal tract. The resulting metabolites are absorbed in the organism and some are excreted in milk. The impact of these compounds on human health divides opinion. Some scientists believe that they might have adverse health effects. Others believe the opposite, especially with regard to their microbial metabolites, such as equol. Whatever one's view on the subject, scientists need accurate, sensitive and rapid analytical methods in order to continue the research on clarifying the phytoestrogen issue. Cow's milk is an animal product that is common in the human diet, and it is therefore important to evaluate its content of phytoestrogen metabolites. In order to study the human intake of equol via commercial milk, an analytical method was developed and validated following EMA/CVMP/VICH/463202/2009 guidelines. Enzymatic hydrolysis was used to release the equol. It was then extracted using double liquid/liquid extraction and analyzed using UPLC®-MS/MS, with an analysis runtime of only 5 min. This analytical method produced a linear calibration curve with a high correlation coefficient (R2≥0.996) between 5 and 1,000 ng mL−1. Good intra- and inter-day precision (RSDs≤5.3% and ≤5.2%, respectively) and accuracy (bias≤8.6%) were achieved. The recovery rate differed slightly among the different types of milk, ranging between 60.6±1.09% and 82.3±5.21%. Good method repeatability was observed (RSDs<15%). There was neither a matrix effect nor a carry-over effect, and the sample extracts were stable during storage for at least 7 days at −21°C and 5°C. In order to apply the proposed method and obtain an initial estimate of equol concentration in cow’s milk in Belgium, 44 samples of various brands found in several supermarkets and 5 raw milk samples from Walloon farms were analyzed. Equol was found in all the samples analyzed, with a concentration ranging from 10 to 50 ng mL−1 for conventional milk and from 70 to 130 ng mL−1 for organic milk. These results were compared with other European studies and the same trend was observed. The results obtained show the specificity, sensitivity and precision of this method for analyzing oestrogenic metabolite-equol in cow’s milk. This study should be extended to include a greater number of samples and be implemented over a longer period to see if there is a correlation between livestock practice and/or sample origins with the equol content in milk. The addition of other phytoestrogen compounds with this method, using UPLC®-MS/MS technology, could also lead to more reliable monitoring of these compounds in dairy production. [less ▲]

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See detailDo aphids actively search for ant partners?
Fischer, Christophe ULg; Vanderplanck, Maryse; Lognay, Georges ULg et al

in Insect Science (in press)

The aphid–ant mutualistic relationships are not necessarily obligate for neither partners but evidence is that such interactions provide them strong advantages in terms of global fitness. While it is ... [more ▼]

The aphid–ant mutualistic relationships are not necessarily obligate for neither partners but evidence is that such interactions provide them strong advantages in terms of global fitness. While it is largely assumed that ants actively search for their mutualistic partners namely using volatile cues; whether winged aphids (i.e. aphids’ most mobile form) are able to select ant-frequented areas had not been investigated so far. Ant-frequented sites would indeed offer several advantages for these aphids including a lower predation pressure through ant presence and enhanced chances of establishing mutuaslistic interactions with neighbour ant colonies. In the field, aphid colonies are often observed in higher densities around ant nests, which is probably linked to a better survival ensured by ants’ services. Nevertheless, this could also result from a preferential establishment of winged aphids in ant-frequented areas. We tested this last hypothesis through different ethological assays and show that the facultative myrmecophilous black bean aphid, Aphis fabae L., does not orientate its search for a host plant preferentially towards ant-frequented plants. However our results suggest that ants reduce the number of winged aphids leaving the newly colonized plant. Thus, ants involved in facultative myrmecophilous interactions with aphids appear to contribute to structure aphid populations in the field by ensuring a better establishment and survival of newly established colonies rather than by inducing a deliberate plant selection by aphid partners based on the proximity of ant colonies. [less ▲]

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See detailEfficiency of pheromone-based formulations against phytophagous pests
Fassotte, Bérénice ULg; Vandereycken, Axel ULg; Chevalier Mendes Lopes, Thomas ULg et al

Conference (2015, May 19)

Innovative integrated pest management methods are needed to overcome market withdrawal of synthetic pesticides. Therefore, the identification of environment-friendly bio-products carrying direct or ... [more ▼]

Innovative integrated pest management methods are needed to overcome market withdrawal of synthetic pesticides. Therefore, the identification of environment-friendly bio-products carrying direct or indirect biocide activity is one promising alternative option. Our researches focus on the identification of appropriate formulations releasing volatile organic compounds that are attractant for natural enemies of insect pests. However, the elaboration of slow-release devices that ensure stable and controlled release of active volatile compounds is quite challenging. Here, we developed a formulation based on E-β-farnesene and (-)-β-caryophyllene, these two semiochemicals having strong attractive potential on aphid natural enemies including lady beetles and hoverflies. Both compounds were encapsulated together in alginate gel beads. The blend efficiency was first evaluated through laboratory assays, and then in wheat and broad bean fields, by considering the abundance and diversity of aphids and their natural enemies. [less ▲]

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See detailWhat makes the invasive Harmonia axyridis so successful? Six years of research in Gembloux provide additional answers
Fassotte, Bérénice ULg; Durieux, Delphine ULg; Vandereycken, Axel ULg et al

Conference (2015, May 14)

Following the introduction of the invasive species Harmonia axyridis (Pallas) in Europe, many research works were conducted on its ecological, economic and social impacts. Recently, our team has been ... [more ▼]

Following the introduction of the invasive species Harmonia axyridis (Pallas) in Europe, many research works were conducted on its ecological, economic and social impacts. Recently, our team has been involved in the characterization of the behavioral traits making this lady beetle species so successful. The main conclusions of two PhD works will be shortly presented: (1) Through a six-year inventory performed in Belgian agroecosystems, we have demonstrated that H. axyridis has become well established and was among the most abundant aphidophagous predatory species, causing a severe depression of biodiversity, even if communities of aphid predators are still quite diversified. (2) The social issues associated with the establishment of overwintering aggregations in human constructions were also carefully investigated. We have demonstrated the importance of social interactions on the establishment and cohesion of the aggregates. Finally, we have demonstrated that the deposition of a set of saturated and non-saturated hydrocarbons on the surfaces where the lady beetles were settling on, allowed their conspecifics to follow their markings and join the group. [less ▲]

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See detailFirst evidence of a volatile sex pheromone in Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae)
Fassotte, Bérénice ULg; Fischer, Christophe ULg; Durieux, Delphine ULg et al

Conference (2015, May 13)

To date, volatile sex pheromones have not been identified in the Coccinellidae family; yet, various studies have suggested that such semiochemicals exist. Here, we collected volatile chemicals released by ... [more ▼]

To date, volatile sex pheromones have not been identified in the Coccinellidae family; yet, various studies have suggested that such semiochemicals exist. Here, we collected volatile chemicals released by virgin females of the multicolored Asian lady beetle, Harmonia axyridis (Pallas), which were either allowed or not allowed to feed on aphids. Virgin females in the presence of aphids, exhibited “calling behavior”, which is commonly associated with the emission of a sex pheromone in several Coleoptera species. These calling females were found to release a blend of volatile compounds that is involved in the remote attraction (i.e., from a distance) of males. Gas Chromatography Mass Spectrometry (GC-MS) analyses revealed that (–)-β-caryophyllene was the major constituent of the volatile blend (ranging from 80 to 86%), with four other chemical components also being present; β-elemene, methyl-eugenol, α-humulene, and α-bulnesene. In a second set of experiments, the emission of the five constituents identified from the blend was quantified daily over a 9-day period after exposure to aphids. We found that the quantity of all five chemicals significantly increased across the experimental period. Finally, we evaluated the activity of a synthetic blend of these chemicals by performing bioassays which demonstrated the same attractive effect in males only. The results confirm that female H. axyridis produce a volatile sex pheromone. These findings have potential in the development of more specific and efficient biological pest-control management methods aimed at manipulating the behavior of this invasive lady beetle. [less ▲]

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See detailPhysicochemical properties and thermal behaviour of African wild mango (Irvingia gabonensis) seed oil.
Yamoneka, Juste; Malumba Kamba, Paul ULg; Blecker, Christophe ULg et al

Poster (2015, March 15)

African wild mango (lrvingia gabonensis) is now recognized for its numerous food and medicinal uses. This plant produces seeds rich in fat, which is traditionally used as a soup thickener. in the present ... [more ▼]

African wild mango (lrvingia gabonensis) is now recognized for its numerous food and medicinal uses. This plant produces seeds rich in fat, which is traditionally used as a soup thickener. in the present study, the proximate composition of seeds from lrvingia gabonensis is reported. The oil from the seeds was then solvent extracted; its fatty acid (FA) and triacylglycerol (TG) profiles were determined. Besides this chemical characterization, the melting and crystallization behaviour of the extracted fat was studied by pNMR, DSC and X-ray diffraction. The result of this investigation showed that the seeds from lrvingia gabonensis (IG) represent an important source of lipids (69-75%), rich in myristic (49.8%) and lauric acid (37%). This fat can be classified among "lauric fats". IG oil presents a good oxidative stability due to its low content in unsaturated fatty acid. The melting profiles of IG oil indicates that a high amount of fat remains solid at temperatures up to 30°C; the complete melting was detected at around 40C. The most stable polymorph of this fat is the β'1 -form. [less ▲]

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See detailFood Compounds from Meadow Grasshoppers
Paul, Aman ULg; Frederich, Michel ULg; Uyttenbroeck, Roel ULg et al

Poster (2015, March 15)

Eating insects as food, particularly grasshopper is practiced in many cultures throughout the world. Meadow grasshopper (Chorthippus parallelus) is commonly found in Europe and some part of Asia. It is ... [more ▼]

Eating insects as food, particularly grasshopper is practiced in many cultures throughout the world. Meadow grasshopper (Chorthippus parallelus) is commonly found in Europe and some part of Asia. It is already known that grasshoppers of Chorthippus species are consumed as food in countries such as Thailand. With the aim of evaluating the nutritional potential of this insect species the proximate nutritional composition of grasshoppers caught from the local fields was realized. Besides this, the fatty acid profile of extracted lipids, amino acid profile and mineral composition of the insect was also revealed. Results suggest that meadow grasshopper is an excellent source of protein and essential amino acids. Lipids extracted from the grasshopper have an interesting fatty acid composition. Also the grasshopper contains some minerals that are important for body. With such protein content, amino acid profile, fatty acid profile of the lipids and mineral content this grasshopper species could present an interesting alternate to conventional protein sources. [less ▲]

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See detailPhysicochemical properties and thermal behaviour of African wild mango (Irvingia gabonensis) seed oil.
Yamoneka, Juste; Malumba Kamba, Paul ULg; Blecker, Christophe ULg et al

Poster (2015, March 15)

Plants belonging Dacryodes and lrvingia genus have great economic importance in Central and West Africa. lrvingia gabonensis (IG) produces a seed rich in fats, traditionally used as a soup thickener ... [more ▼]

Plants belonging Dacryodes and lrvingia genus have great economic importance in Central and West Africa. lrvingia gabonensis (IG) produces a seed rich in fats, traditionally used as a soup thickener. Fruit of Dacryodes edulis (DS) contains a pulp how are also rich in fat. Its seed constitute a big waste problem in towns and village remains not exploitable by local people however that may be valued as a resource for various components. Some study shows that this seed contented a proportion of oils that would be an alternative in the substitution of diesel relevant to their physicochemical properties. Despite the potential of two different oils, theirs scientific data still lack. In this work, thermo-physical behaviour of those two oils is compared in the aim to improving knowledge about properties of those oils that will promote their valorisation in industry scale. The result of this investigation showed that IGO have a highest proportion of oil content with 72.38% compared to DSO (14.64%). IGO is rich in myristic (49.8%) and lauric fatty acid (37%) but DSO sample was found to possess a higher proportion of linoleic acid (35.13%), palmitic (32.67%), oleic (17.70%) but lower proportion of stearic (9.97%). SFC of IGO was the highest at all temperatures. IGO is solid at room temperature with a complete melting at 40°C but DSO is liquid at room temperature. The polymorphism profile of IGO and DSO shows the 13' form stable during heating and a transition to liquid state without passage at β form. [less ▲]

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See detail10. Perspectives - 1. La Lutte contre les pucerons grâce aux odeurs: développement d'une formulation phéromonale
Fassotte, Bérénice ULg; Vandereycken, Axel ULg; Chevalier Mendes Lopes, Thomas ULg et al

in Watillon, Bernard; Bodson, Bernard (Eds.) Livre Blanc Céréales (2015, February 25)

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See detail7. Lutte intégrée contre les ravageurs - 2.1 Suivi des populations de cécidomyie équestre, Haplodiplosis marginata, grâce au développement d'un piège à phéromone
Censier, Florence ULg; Fischer, Christophe ULg; Chavalle, Sandrine et al

in Watillon, Bernard; Bodson, Bernard (Eds.) Livre Blanc Céréales (2015, February 25)

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See detailInvestigating the Effects of Plant Root Exudates on PAHs Bioavailability to Soil Microorganisms in Contaminated Brownfields : Research Methodology.
Davin, Marie ULg; Lognay, Georges ULg; Fauconnier, Marie-Laure ULg et al

Poster (2015, January 30)

As a result of heavy industrial past activities, an estimated 6,000 brownfields require remediation in Wallonia. This number rises to over 3.5 million in Europe. Polycyclic Aromatic Hydrocarbons (PAHs ... [more ▼]

As a result of heavy industrial past activities, an estimated 6,000 brownfields require remediation in Wallonia. This number rises to over 3.5 million in Europe. Polycyclic Aromatic Hydrocarbons (PAHs) represent 17% of treated pollutants in Wallonia (Aldric et al., 2011). Current remediation techniques are rather expensive and technically demanding (Megharaj et al., 2011). Based on the observation that PAHs soil content decreases in the presence of plants (Cheema et al., 2010), the PhD aims at developing alternative PAHs remediation techniques in brownfields. It is articulated around three research axes. The first axis focusses on plant exudates and how they may improve PAHs bioavailability to soil microorganisms and enhance their degradation. This will be investigated by (i) characterizing several contaminated soils (physico-chemical parameters) and PAH content and factors of bioavailability, (ii) selecting a plant model and collecting root exudates, and (iii) evaluating the effects of exudates on PAHs bioavailability. The objective of the second axis is to evaluate the effects of plant exudates on PAHs degrading microorganisms by (i) comparing PAHs biodegradation in the presence/absence of exudates and (ii) assessing the potential toxic effects of exudate compounds on the microbial communities. The aim of the third axis is to study plant-pollutants interactions by (i) establishing the plant tolerance to several contamination levels and (ii) following PAHs bioavailability when facing real exudation rates, on the field. [less ▲]

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See detailValidating the use of an ultra-performance liquid chromatography with tandem mass spectrometry method to quantify equol in cow's milk
Daems, Frédéric ULg; Jasselette, Christophe; Romnee, Jean-Michel et al

in Dairy Science & Technology (2015)

Cow’s milk can be used as a potential source of equol in the human diet. In order to study human intake, however, it is necessary to develop a reliable and sensitive analytical method. This paper reports ... [more ▼]

Cow’s milk can be used as a potential source of equol in the human diet. In order to study human intake, however, it is necessary to develop a reliable and sensitive analytical method. This paper reports on the validation of an analytical method using ultra-performance liquid chromatography coupled with a tandem mass spectrometry detector to quantify the equol in commercial milks (raw, whole, semi-skimmed, and skimmed milk). The equol was initially released using enzymatic hydrolysis, and it was then extracted using a double liquid/liquid extraction. The analytical method produced a linear calibration curve with a high correlation coefficient (R 2 ≥ 0.996) between 5 and 1,000 ng.mL−1. Good intra- and inter-day precision (≤5.3% and ≤ 5.2%, respectively) and accuracy (≤8.6%) were achieved. The recovery rate differed slightly among the different types of milk, ranging between 60.6 ± 1.09% and 82.3 ± 5.21%. Good method repeatability was observed (<15%). There was neither matrix effect nor carry-over effect, and the sample extracts were stable for at least 7 days of storage at −21 °C and 5 °C. The method proved to be specific, sensitive, precise, and accurate and was used for the first time to quantify the equol content in Belgian commercial cow’s milk. In all the samples analyzed, equol was present at a concentration ≥10 ng.mL−1 and had a significantly higher content in organic than in conventional milk. The study also found that the mean concentrations of equol were similar for each type of commercial conventional cow’s milk. [less ▲]

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See detailChemical composition and antibacterial activitiy of the essential oils of Algerian Myrtus communis L.
Hennia, Aïcha; Brada, Moussa; Nemmiche, Saïd et al

in Journal of Essential Oil Research (2015)

Myrtus communis L. leaf essential oils from Algeria were analyzed by gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS). A total of thirty-four components were identified accounting ... [more ▼]

Myrtus communis L. leaf essential oils from Algeria were analyzed by gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS). A total of thirty-four components were identified accounting for 95% of the oil. The main compounds were limonene (23.4%), linalool (15.4%), geranyl acetate (10.9%), α-pinene (10.7%), linalyl acetate (8.2%) and 1,8-cineole (6.6%).The antimicrobial evaluation showed that myrtle oil exhibited good antibacterial activity against Staphylococcus aureus, Proteus mirabilis and Kleibsiella pneumonia, but differed according to the strains. Conversely, it was not active against Pseudomonas aeruginosa. [less ▲]

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See detailMyzus persicae feeding on water stressed Arabidopsis affects the emission profile of plant volatile organic compounds
Truong, Dieu-Hien; Delaplace, Pierre ULg; Brostaux, Yves ULg et al

in Journal of Environment and Ecology (2014), 5(2),

Emissions of volatile organic compounds (VOCs) by water-controlled or water-stressed Arabidopsis thaliana infested or not infested with Myzus persicae were evaluated by headspace solid phase ... [more ▼]

Emissions of volatile organic compounds (VOCs) by water-controlled or water-stressed Arabidopsis thaliana infested or not infested with Myzus persicae were evaluated by headspace solid phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS). The infestations were maintained for 0–24 h, 24–48 h, and 48–72 h, and the emission profile for each time period was determined. Under these controlled conditions, the proportion of 4-methylpentyl isothiocyanate and dimethyl disulfide emitted by aphid-infested, water-stressed Arabidopsis was greater than that for aphid-infested water-controlled Arabidopsis over the 48–72 h sampling period. The proportion of terpene emitted by aphid-infested water-stressed plants also significantly increased compared with the other treatments over the three assayed sampling periods. In contrast, the proportion of 2-ethylhexanal (the only detected aldehyde) and ketones for the water-controlled plants generally remained high following aphid infestation. Taken together, these original data ascertain that abiotic factors can greatly interact to biotic stresses to alter the VOC emission profiles of plants. [less ▲]

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See detailFirst Evidence of a Volatile Sex Pheromone in Lady Beetles
Fassotte, Bérénice ULg; Fischer, Christophe ULg; Durieux, Delphine ULg et al

in PLoS ONE (2014)

To date, volatile sex pheromones have not been identified in the Coccinellidae family; yet, various studies have suggested that such semiochemicals exist. Here, we collected volatile chemicals released by ... [more ▼]

To date, volatile sex pheromones have not been identified in the Coccinellidae family; yet, various studies have suggested that such semiochemicals exist. Here, we collected volatile chemicals released by virgin females of the multicolored Asian lady beetle, Harmonia axyridis (Pallas), which were either allowed or not allowed to feed on aphids. Virgin females in the presence of aphids, exhibited “calling behavior”, which is commonly associated with the emission of a sex pheromone in several Coleoptera species. These calling females were found to release a blend of volatile compounds that is involved in the remote attraction (i.e., from a distance) of males. Gas Chromatography-Mass Spectrometry (GC-MS) analyses revealed that (–)-β-caryophyllene was the major constituent of the volatile blend (ranging from 80 to 86%), with four other chemical components also being present; β-elemene, methyl-eugenol, α-humulene, and α-bulnesene. In a second set of experiments, the emission of the five constituents identified from the blend was quantified daily over a 9-day period after exposure to aphids. We found that the quantity of all five chemicals significantly increased across the experimental period. Finally, we evaluated the activity of a synthetic blend of these chemicals by performing bioassays which demonstrated the same attractive effect in males only. The results confirm that female H. axyridis produce a volatile sex pheromone. These findings have potential in the development of more specific and efficient biological pest-control management methods aimed at manipulating the behavior of this invasive lady beetle. [less ▲]

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See detailPlutella xylostella (L.) infestations at varying temperatures induce the emission of specific volatile blends by Arabidopsis thaliana (L.) Heynh
Hien, Truong Thi Dieu ULg; Delory, Benjamin ULg; Brostaux, Yves ULg et al

in Plant Signaling & Behavior (2014)

The effect of combined abiotic and biotic factors on plant volatile organic compound (VOC) emissions is poorly understood. This study evaluated the VOC emissions produced by Arabidopsis thaliana (L.) Col ... [more ▼]

The effect of combined abiotic and biotic factors on plant volatile organic compound (VOC) emissions is poorly understood. This study evaluated the VOC emissions produced by Arabidopsis thaliana (L.) Col-0 subjected to three temperature regimes (17, 22, and 27 °C) in the presence and absence of Plutella xylostella larvae over two time intervals (0–4 and 4–8 h), in comparison to control plants. The analyses of VOCs emitted by Arabidopsis plants were made by headspace solid phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS). It was found that certain volatile groups (e.g., alcohols, ketones, aldehydes, and terpenes) are induced by both single factors (temperature or larval infestation) and combined factors (temperature and larvae interactions), whereas other volatile groups (e.g., isothiocyanates [ITCs] and nitrile) were specific to the experimental conditions. ITCs (mainly 4-methylpentyl isothiocyanate) were emitted from plants subjected to larval infestation at 17 and 27 °C after the two time intervals. The proportions of sulfides (mainly dimethyl disulfide) and 4-(methylthio) butanenitrile were significantly higher on herbivore-infested plants at 22 °C compared to the other treatments. Overall, our findings indicate that changes in all experimental conditions caused significant changes to the VOC emissions of Arabidopsis plants. Therefore, the interaction between temperature and larval feeding may represent an important factor determining the variability of volatile emissions by plants subjected to multiple simultaneous factors. [less ▲]

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See detailUne phéromone sexuelle chez la coccinelle asiatique, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae)
Fassotte, Bérénice ULg; Fischer, Christophe ULg; Durieux, Delphine ULg et al

Conference (2014, October)

A ce jour, aucune phéromone sexuelle n’a pu être mise en évidence chez les Coccinellidae. Cependant, diverses études suggèrent que de telles molécules sont impliquées dans la communication sexuelle chez ... [more ▼]

A ce jour, aucune phéromone sexuelle n’a pu être mise en évidence chez les Coccinellidae. Cependant, diverses études suggèrent que de telles molécules sont impliquées dans la communication sexuelle chez les coccinelles. Afin de vérifier cette hypothèse, nous avons collecté les composés organiques volatils émis par la coccinelle asiatique, Harmonia axyridis (Pallas), en présence ou en absence de pucerons. En présence de pucerons, les femelles vierges présentent un « comportement d’appel » qui est notamment associé à l’émission d’une phéromone sexuelle volatile chez plusieurs espèces de Coléoptères. D’autre part, des tests éthologiques ont démontré que les femelles émettent des composés volatils qui attirent les mâles à distance. Enfin, les prélèvements ont été analysés par chromatographie en phase gazeuse couplée à la spectrométrie de masse. Les analyses ont mis en évidence cinq composés volatils spécifiques provenant des femelles, aucun d’entre eux n’étant émis pas les mâles. L’identification a révélé la présence de (–)-β-caryophyllène, de β-élémène, de méthyl-eugénol, d’α-humulène et d’α-bulnésène, exclusivement produits par les femelles nourries de pucerons et dont les quantités respectives augmentent progressivement au cours de la période de prélèvement. Les résultats confirment donc que les femelles H. axyridis produisent une phéromone sexuelle volatile. Ceux-ci devraient permettre de promouvoir le développement de méthodes de gestion plus efficaces afin de manipuler les mouvements de cette coccinelle invasive et de réduire les impacts négatifs qu’elle occasionne sur la biodiversité. [less ▲]

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See detailMinerals and trace elements in traditional foods of rural areas of Lhasa Prefecture, Tibet Autonomous Region (P.R. China)
DERMIENCE, Michael ULg; Li, Xiao Wei; Mathieu, Françoise et al

in Journal of Food Composition and Analysis (2014), 35(2),

Traditional foods play a major role in the diet of rural people living in the Tibet Autonomous Region of the People's Republic of China. Because these foods are mainly derived from local agriculture as ... [more ▼]

Traditional foods play a major role in the diet of rural people living in the Tibet Autonomous Region of the People's Republic of China. Because these foods are mainly derived from local agriculture as well as artisanal production, their mineral composition may show significant discrepancies when compared with food composition data. This study aims at providing relevant data on the mineral composition of the main Tibetan foods. Sixteen different foodstuffs were sampled, including water, concentrated brewed black tea, chang, tsampa, wheat flour, dried cheese, dried yak meat, dried mutton, blood sausage, dried wild peaches, dried Chinese radish, and dried nettles. They were analyzed by inductively coupled plasma mass spectrometry (ICP-MS) for 19 minerals: Na, K, P, Ca, Mg, Fe, Zn, Mn, Cu, Ni, Se, Mo, Al, As, Cr, Co, Cd, Pb, and V. The validity of the results was ensured by the use of standard reference materials. A statistical comparison of the mean mineral contents of the analyzed foods against food composition data from the China Food Composition (CFC) table was carried out. It revealed significant discrepancies, emphasizing the importance of food analysis for nutritional assessment in Tibet autonomous region. To the best of our knowledge, the mineral compositions of some traditional Tibetan foods are here reported for the first time. [less ▲]

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See detailDétermination de la teneur en équol dans les laits commercialisés en Wallonie (Belgique)
Daems, Frédéric ULg; Jasselette, Christophe; Franckson, Delphine et al

Poster (2014, June 13)

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See detailIs Contact Between Conspecifics Involved in the Cohesion of Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) Aggregations?
Durieux, Delphine ULg; Fassotte, Bérénice ULg; Fischer, Christophe ULg et al

in Journal of Insect Behavior (2014), 27(1), 1-13

The multicolored Asian ladybeetle, Harmonia axyridis (Pallas), exhibits a gregarious behavior during unfavorable winter conditions. Although this behavior is currently described as a phenomenon occurring ... [more ▼]

The multicolored Asian ladybeetle, Harmonia axyridis (Pallas), exhibits a gregarious behavior during unfavorable winter conditions. Although this behavior is currently described as a phenomenon occurring only during winter, aggregations can also be observed outside overwintering conditions. However, the substrate markings previously highlighted as being involved in the wintry aggregation of this exotic species do not seem to be used by non-overwintering individuals to aggregate. This fact suggests then that other cues are responsible for the induction of this behavior. In this work, we have tested the hypothesis that direct contact between non-overwintering individuals stimulates the establishment of clusters. Binary choice experiments highlighted the involvement of elytral cuticular compounds in this phenomenon. Chromatographic analyses showed that the active extracts contained mainly hydrocarbons, including saturated, mono-unsaturated, and di-unsaturated homologues. Physical contact also seems to be involved in the non-overwintering aggregative behavior of H. axyridis, but to a lesser extent than these natural compounds. These findings could eventually be used to develop new control methods of these pest populations and so, reduce the adverse impacts it causes on biodiversity. [less ▲]

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