References of "Lognay, Georges"
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See detailInfluence of the secondary endosymbiont Serratia Symbiotica on the resistance to the parasitism in the aphid Acyrthosiphon pisum
Attia, Sabrine; Foray, Vincent; Louâpre, Philippe et al

in Journal of Entomology and Zoology Studies (in press)

Aphids have an obligate association with the primary symbiont Buchnera aphidicola and is known to affect aphid fitness. Aphids commonly harbour other facultative bacterial endosymbionts and may benefit ... [more ▼]

Aphids have an obligate association with the primary symbiont Buchnera aphidicola and is known to affect aphid fitness. Aphids commonly harbour other facultative bacterial endosymbionts and may benefit from their presence through increased resistance to parasitoids [1]. Present results suggest that the ability of hosts to defend against natural enemies depend not only on the presence of symbionts but also on the host genotype. Aphids represent a complex micro-environment for the parasitoid larvae and both the aphid physiology and endosymbiont influence their survival until mummification. [less ▲]

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See detailOviposition deterring effect of Ocimum basilicum L. (Lamiaceae) on Tuta absoluta Meyrick (Lepidoptera: Gelechiidae)
Yarou, Boni Barthélémy ULg; Bawin, Thomas ULg; Boullis, Antoine ULg et al

Poster (2016, December 02)

Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) is one of the most important pests of tomato, reducing crop yield in greenhouses and fields, in several countries around the world. Because synthetic ... [more ▼]

Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) is one of the most important pests of tomato, reducing crop yield in greenhouses and fields, in several countries around the world. Because synthetic insecticides lead to resistance and have adverse effects on natural enemies and producers’ health, there is a need for alternatives. In this study, we assess the oviposition deterring effect of O. basilicum using dual-choice behavioral assays performed in flight tunnels. Two modalities were tested, i.e. (1) a tomato plant associated either with an O. basilicum plant versus a tomato plant associated with a plastic pot only filled with potting soil, and (2) a tomato plant with basil essential oil (EO) formulated in paraffin oil (PO) versus a tomato plant with PO only. A 1 ml cylindrical polyethylene plug loaded with 100 µl of solution (formulated EO or PO) was placed on each plant as a diffuser. Forty-eight hours after the release of unsexed adult individuals randomly sampled from the rearing in the central area of the tunnel, we found that plants and EOs reduced T. absoluta oviposition behavior on a nearby located tomato plant. GC-MS analyses showed that the major constituents include estragol (73.8%), linalool (8.6%), β-elemene (2.9%) in O. basilicum essential oils and E-α-bergamotene (38.9%), methyl eugenol (26.1 %), E-β-ocimene (17.7 % ) in O. basilicum VOCs collected with solid-phase micro-extraction method. These results suggest a valuable potential of O. basilicum and associated essential oils as component of an integrated management strategy against the tomato leafminer. [less ▲]

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See detailNutritional Composition and Rearing Potential of the Meadow Grasshopper (Chorthippus parallelus Zetterstedt)
Paul, Aman ULg; Frederich, Michel ULg; Uyttenbroeck, Roel ULg et al

in Journal of Asia-Pacific Entomology (2016), 19(4), 1111-1116

Insects, particularly those belonging to the family Acrididae (grasshoppers), are commonly consumed as human food in many parts of the world. Grasshoppers of the species Chorthippus parallelus are ... [more ▼]

Insects, particularly those belonging to the family Acrididae (grasshoppers), are commonly consumed as human food in many parts of the world. Grasshoppers of the species Chorthippus parallelus are abundantly found throughout Europe. However, these insects were not consumed by Europeans till now, but could possibly be used as human food, which is why we investigated their chemical composition. We found that they contain high level of proteins (69%), with an excellent amino acid profile and protein digestibility (97%). Furthermore, specimens of C. parallelus have an interesting fatty acids profile and minerals composition. Preliminary toxicity assessment indicates that these insects do not exhibit toxicity towards neutrophil cells (white blood cells). These data suggest that C. parallelus could be considered for human consumption. Rearing trials done during the study show that commercial rearing could be developed to produce sufficient biomass for sustaining human consumption. [less ▲]

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See detailImpact of skimming and microfiltration processes on equol concentration in milk
Daems, Frédéric ULg; Ninane, Véronique; Romnee, Jean-Michel et al

Poster (2016, October 19)

Equol is a microbial metabolite of isoflavones that could be used as therapeutic agent against several diseases and cancers. Cow's milk could be a potential source of equol in the human diet, but more ... [more ▼]

Equol is a microbial metabolite of isoflavones that could be used as therapeutic agent against several diseases and cancers. Cow's milk could be a potential source of equol in the human diet, but more studies are needed on the changes in equol concentration during the technological processing of milk and dairy products. This first exploratory study sought to assess the impact of industrial skimming and microfiltration processes on equol concentration in conventional cow's milk. The milk samples used in this study came from bulk cow’s milk collected in Wallonia (Belgium), by a local dairy and processed in a local cheese factory. Six random sampling were conducted during spring and, for each of them, samples from raw, skimmed and microfiltered milk were analyzed. Equol was present in all samples at a concentration of between 3.2 and 10.3 µg.L-1. A Wilcoxon's signed rank test was then performed on the difference of data, having raw milk as reference, irrespective of the collection date. The results showed that the skimming process slightly increased the equol concentration in milk and therefore that equol had no or little affinity with the lipid milk fraction. The results also showed that, with the microfiltration process, a small proportion of equol was retained. Equol concentration has returned to the same level as that found in raw milk. This might be because of a chemical affinity either with bigger molecules that are physically retained or through direct interaction with the membrane. This scoping study paves the way for more extensive studies on the interaction between equol and other components of the milk. [less ▲]

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See detailValorization of Seeds from Some Field Border Flowering Seeds
Paul, Aman ULg; Danthine, Sabine ULg; Mutwale Kapepula, Paulin ULg et al

Poster (2016, September 20)

Flowering strips are now being increasingly cultivated along the fields to improve biodiversity. However after serving for the desired function, these plants have no utilization besides animal feed. It ... [more ▼]

Flowering strips are now being increasingly cultivated along the fields to improve biodiversity. However after serving for the desired function, these plants have no utilization besides animal feed. It could be really interesting to valorize some commonly grown plant in these strips to render food or health promoting compounds. With this objective in mind the seeds of Achillea millefolium, Anthriscus sylvestris and Prunella vulgaris were investigated for lipids, proteins and phenolic content. Further the lipids were analyzed for fatty acid profile using gas chromatography and the phenolic compounds in the methanolic extract of defatted seeds were identified using HPLC-DAD. The antiradical activity of the methanolic extracts obtained from defatted seeds was investigated using DPPH and ABTS assays. The anti-inflammatory potential of these seed extracts was evaluated on the reactive oxygen species (ROS) production by stimulated neutrophils and on the specific activity of myeloperoxidase (MPO), a pro-oxidant enzyme marker of inflammation. Seeds from all three plants were analyzed with interesting levels of lipids, proteins and phenolic content. Linoleic acid, oleic acid and alpha-linolenic acid were the major fatty acids analyzed in A. millefolium, A. sylvestris and P. vulgaris respectively. On the other hand different phenolic acid formed the major phenolic constituents. Seed extracts displayed high ABTS and DPPH radical-scavenging activities in a dose dependent manner. Also a strong dose dependent anti-inflammatory activity of all three extracts was observed against ROS production by neutrophils and MPO activity. Results indicate that these seed show a great potential to render lipids which could be utilized as human food, further the defatted seeds could be directly included in human diet due to interesting levels of proteins and anti-inflammation ability. [less ▲]

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See detailDevelopment of a semiochemical-based control method against the walnut husk fly, Rhagoletis completa Cresson
Sarles, Landry ULg; Lognay, Georges ULg; Verhaeghe, Agnès et al

Poster (2016, September 15)

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See detailCan tropical basil be integrated in vegetable crop pest management?
Yarou, Boni Barthélémy ULg; Verheggen, François ULg; Heuskin, Stéphanie ULg et al

Poster (2016, May 17)

To address human and environmental health issues related to the use of synthetic pesticides, it is important to explore other ecological pest management approaches. Within this context, a study was ... [more ▼]

To address human and environmental health issues related to the use of synthetic pesticides, it is important to explore other ecological pest management approaches. Within this context, a study was conducted to evaluate the toxic and repellent effect of Ocimum gratissimum L. (Lamiaceae) on Myzus persicae S. (Aphididae). The toxicity of O. gratissimum essential oil (EO) was evaluated on M. persicae comparing 3 concentrations (0.001%; 0.01% and 0.1%) to a control (15% sucrose). Mortality rate and fecundity were assessed for each concentration. The observations were made daily, for 4 days, on 12 replicates per treatment. To test the repellent effect of O. gratissimum plants, 2 treatments were compared: a group of 8 Amaranthus cruentus L. (Amaranthaceae) plants with 1 plant of O. gratissimum in the middle and a group of 9 A. cruentus plants (control). The distribution of aphids was analyzed 12 days after the middle plant infestation (20 aphids per plant) for each treatment (6 replicates per treatment). O. gratissimum EO was found toxic from a concentration of 0.01%, with a mortality rate of 34% versus 12% for the control ; The fecundity felt from 30 larvae after 4 days (control) to 15 larvae for the 3 doses of the EO. The analysis with the generalized linear mixed model with Poisson error distribution followed by Turkey test (5 %) showed that EO is significantly more toxic than the control, both for mortality and fecundity (p <0.001). In association test, the population of M. persicae (15 aphids per plant) was significantly (p<0,001) lower when A. cruentus plants was associated with O. gratissimum plant than with the control (22 aphids per plant). Furthermore, the population increases gradually as one moves away from the infestation point in association test whereas it decreases in the control. With regards to these results, it appears that O. gratissimum has biocide effects on M. persicae. This plant may be used in an integrated pest management strategy in the production of vegetable to reduce the use of synthetic pesticides and avoid chemicals residues. [less ▲]

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See detailMechanisms involved in pearlfish resistance to holothuroid toxins
Brasseur, Lola; Parmentier, Eric ULg; Caulier, Guillaume et al

in Marine Biology (2016), 163(129), 1-14

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See detailQuantification of four Isoflavones in Forages with UPLC®-MS/MS, using the Box-Behnken Experimental Design to Optimize Sample Preparation
Daems, Frédéric ULg; Romnee, Jean-Michel; Rasse, Catherine et al

in Chromatographia (2016), 79(11), 711-725

A performant method for the simultaneous quantification of daidzein, genistein, formononetin and biochanin A in forages using an UPLC®-MS/MS was developed and fully validated. The ultrasound-assisted ... [more ▼]

A performant method for the simultaneous quantification of daidzein, genistein, formononetin and biochanin A in forages using an UPLC®-MS/MS was developed and fully validated. The ultrasound-assisted extraction and enzymatic hydrolysis used in the sample preparation step were optimized using the Box-Behnken experimental design. The optimal extraction conditions used for a representative mix of forage plants were 80°C, 10 min and 55% methanol, and for hydrolysis they were 20°C, 18 h and pH=6. The chromatographic separation was achieved using an Acquity® UPLC® HSS T3 column, with a water/methanol linear gradient containing 0.01% of formic acid at a 0.55 mL min-1 flow rate. The four isoflavones were detected by ESI mass spectrometry in positive ion MRM mode. The method allows high throughput analyses of samples and showed an adequate linear regression model for all isoflavones over a range from 5 to 125 ng mL-1. There was good intra- and inter-day precision (≤ 8.2% and ≤ 7.6%) and accuracy (≤ 11.4% and ≤ 7.1%). The recovery rates were in an acceptable range of 70-120%, except for biochanin A, where the rate was about 50%. Good method repeatability was also observed, and there was no matrix effect or carry-over problem. The sample extracts were stable for at least 6 days of storage at -21°C and 6°C. The method proved to be sensitive, precise and accurate for discriminating a wide variety of forages likely to be grazed by ruminants according to their isoflavone content and to observe the impact storage process on isoflavone content in forages. [less ▲]

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See detailIn vitro evaluation of protein precipitation capacity of temperate browse species
Vandermeulen, Sophie ULg; Leblois, Julie ULg; Ramírez-Restrepo, Carlos Alberto et al

Poster (2016, February 05)

European agri-environmental policies are promoting the establishment of shrubs and trees on grasslands. The use of browse as fodder requires knowledge on their nutritive value since intensive production ... [more ▼]

European agri-environmental policies are promoting the establishment of shrubs and trees on grasslands. The use of browse as fodder requires knowledge on their nutritive value since intensive production systems are still relying on expensive and environment-costing protein sources. However, information on the influence of temperate condensed tannins (CT)-containing browse forage on rumen protein metabolism is elusive. The study aimed to assess the protein precipitation capacity (PPC) of 10 temperate browse species and establish the correlation between PPC values and plants CT content. PPC of foliage of 3 individuals per woody plants was measured using 2 model proteins: bovine serum albumin (BSA) and casein. The N content in protein solutions (4.6g/L; pH=6.8) was determined before and after adding each forage sample. Extractable CT concentration was quantified by spectrophotometry. The PPC varied across plant species (P<0.001). Corylus avellana had the highest ability to precipitate casein (52.4%). In contrast, the BSA precipitation (18.3%) of this plant was similar to Cornus sanguinea (12.7%), Quercus robur (12.1%) and Crataegus monogyna (11.0%). CT content ranged from 1.4 in Fraxinus excelsior to 82.7g/kg of depigmented sample in Corylus avellana (P<0.001) and was correlated to BSA (r=0.70; P<0.001) and casein PC (r=0.51; P<0.01). It was concluded that woody species could play a significant role in modifying protein metabolism, but further in vivo trials are required. [less ▲]

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See detailUse of response surface methodology to optimize samples preparations in laboratory
Daems, Frédéric ULg; Romnee, Jean-Michel; Lognay, Georges ULg

Conference (2016, January 17)

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See detailAnalytical methods used to quantify isoflavones in cow's milk: a review
Daems, Frédéric ULg; Romnee, Jean-Michel; Heuskin, Stéphanie ULg et al

in Dairy Science and Technology (2016)

This paper provides an update and comprehensive review of the analytical methods used for quantifying isoflavones and their metabolites in cow’s milk. Isoflavones are secondary plant metabolites that are ... [more ▼]

This paper provides an update and comprehensive review of the analytical methods used for quantifying isoflavones and their metabolites in cow’s milk. Isoflavones are secondary plant metabolites that are similar to 17 β-estradiol in chemical structure. They form one of the most common categories of phytoestrogens. Numerous health benefits have been attributed to isoflavones, but many of these compounds are also considered to be endocrine disruptors, with adverse effects on health. These contradictory trends offer an attractive prospect for future research, and therefore, sensitive and reliable analytical methods are required to clarify various issues about isoflavones. For this review, a structured methodology was used to select 26 relevant articles published between 2005 and 2015 from the Scopus and CAB Abstract databases. The review discusses individual steps of the analytical procedures described in these articles, including sample preparation, instrumental analysis and validation. The most commonly used analytical procedure is sample preparation involving liquid-liquid extraction and an enzymatic hydrolysis step followed by liquid chromatography with mass spectrometry analysis. Currently, however, there is no standardized procedure for the sample preparation and analysis of isoflavones in milk. [less ▲]

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See detailBacteria may contribute to distant species recognition in ant–aphid mutualistic relationships
Fischer, Christophe ULg; Detrain, Claire; Thonart, Philippe ULg et al

in Insect Science (2016)

Mutualistic interactions between ant and aphid species have been the subject of considerable historical and contemporary investigations, the primary benefits being cleaning and protection for the aphids ... [more ▼]

Mutualistic interactions between ant and aphid species have been the subject of considerable historical and contemporary investigations, the primary benefits being cleaning and protection for the aphids and carbohydrate-rich honeydew for the ants. Questions remained, however, as to the volatile semiochemical factor influencing this relationship. A recent study highlighted the role of bacterial honeydew volatile compounds in ant attraction. Here, ant’s ability to distantly discriminate two aphid species was investigated based on bacterial honeydew semiochemicals emissions using a two-way olfactometer. Both the mutualistic black bean aphid (Aphis fabae L.) and the non-myrmecophilous pea aphid (Acyrthosiphon pisum Harris) were found to be attractive for the black garden ant (Lasius niger L.). The level of attraction was similar in both assays (control versus one of the aphid species). However, when given a choice between these two aphid species, ants showed a significant preference for Aphis fabae. Honeydew volatiles, mostly from bacterial origins, are known to be a key element in ant attraction. Using the same olfactometry protocol, the relative attractiveness of volatiles emitted by honeydews collected from each aphid species and by bacteria isolated from each honeydew was in investigated. Again, ants significantly preferred volatiles released by Aphis fabae honeydew and bacteria. This information suggests that microbial honeydew volatiles enable ants to distantly discriminate aphid species. These results emphasize the importance of investigating the presence and potential effects of microbes in insect symbioses. [less ▲]

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See detailChemical Characterization of Essential Oils of Mints from Senegal
Diop, Serigne Mbacké; Guèye, Momar Talla; Ndiaye, Ibrahima et al

in Natural Product Communications (2016), 11(0), 1-2

Mints from Senegal were extracted separately from fresh (F) and shade-dried (D) plants by steam distillation. Yields were of 0.28 and 0.21% for M. citrata L., 0.21 and 0.18% for M. x piperita L. and 0.10 ... [more ▼]

Mints from Senegal were extracted separately from fresh (F) and shade-dried (D) plants by steam distillation. Yields were of 0.28 and 0.21% for M. citrata L., 0.21 and 0.18% for M. x piperita L. and 0.10 and 0.19% for M. spicata L. in the fresh and dried plants, respectively. GC/FID and GC/MS analysis revealed that many of the major compounds of essential oils decreased with drying. The prominent components of M. citrata oils were linalool that constituted 45.8% (F) and 42.0% (D) and linalyl acetate 42.7 (F) and 38.5% (D). Mentha x piperita was characterized by menthofuran with 30.7% (F) and 28.1% (D), menthol 15.9(F) and 16.4% (D), menthone 13.0 (F) and 14.2% (D), pulegone 17.6%(F) and 13.8%(D) and 1.8-cineole 3.7%(F) and 3.4% (D). Mentha spicata contained mainly carvone 67.8 and 74.7% and limonene 18.1 and 12.5% in the fresh and dried plants respectively. [less ▲]

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See detailChanges in the isoflavone concentration in red clover (Trifolium pratense L.) during ensiling and storage in laboratory-scale silos
Daems, Frédéric ULg; Decruyenaere, Virginie ULg; Agneessens, Richard et al

in Animal Feed Science & Technology (2016)

Isoflavones constitute one of the most common categories of nonsteroidal estrogen-like substances belonging to the broad group of phytoestrogens. The highest concentrations in the plant kingdom are found ... [more ▼]

Isoflavones constitute one of the most common categories of nonsteroidal estrogen-like substances belonging to the broad group of phytoestrogens. The highest concentrations in the plant kingdom are found in the Fabaceae family. They have become a focus of research because of their estrogenic or anti-estrogenic effect and potential impact on human health. In recent years, several studies have focused on the impact of biotic and abiotic factors and farming management on the isoflavone concentration in plants and their impact on the composition of cow’s milk. Nevertheless, knowledge about the effect of the ensiling process on isoflavone concentration remains limited. The objective of this work was to study the evolution of the concentrations of four compounds (daidzein, formononetin, genistein and biochanin A) in red clover (Trifolium pratense L.) ensiled at harvest. The impact of the field-drying process was also assessed. The plant material was ensiled in laboratory scale silos using vacuum-packed plastic bags and stored over a 6-month period. The quality of the silages was checked throughout the experiment by determining the pH, lactic acid concentration, volatile fatty acids, crude proteins, cellulose and other chemical characteristics. The isoflavone concentration in fresh plant material was 2050, 1766, 306 and 127 µg/g DM for formononetin, biochanin A, genistein and daidzein, respectively. After 4 days of drying in the field, no significant change in isoflavone concentration was found, except for daidzein, which increased twofold. The laboratory-scale silos experiment, however, showed a decrease in isoflavone concentration during the first 2 weeks, followed by stabilization over the 5 remaining months. The concentrations fell by 26, 39, 66 and 73% for daidzein, genistein, biochanin A and formononetin, respectively. Animals fed with silage would therefore absorb fewer isoflavones than those fed with fresh plant material or hay. [less ▲]

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