References of "Wathelet, Bernard"
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See detailGrowth rate of bumblebee larvae is related to pollen amino acids
Moerman, R.; Vanderplanck, Maryse ULiege; Roger, N. et al

in Journal of Economic Entomology (2016), 109(1), 25-30

The use of Bombus terrestris L. commercial colonies for outdoor and greenhouse crop pollination is currently widespread. Colony breeding includes bumblebee feeding, mostly by using the honeybee pollen ... [more ▼]

The use of Bombus terrestris L. commercial colonies for outdoor and greenhouse crop pollination is currently widespread. Colony breeding includes bumblebee feeding, mostly by using the honeybee pollen loads of diverse palynological composition. Because the chemical content of pollen is highly variable, the choice of commercial blend should not be random but has to be carefully selected to ensure the optimal development of workers and then pollination efficacy. In this work, we compared the impact of three common commercial blends on the development of bumblebee microcolonies, namely, Actinidia deliciosa L., Cistus sp., and Salix sp. We focus on amino acids (i.e., composition and amount), as they are currently used as an indicator of diet performance. Five parameters were used to determine microcolonies growth rate: 1) number of eggs, 2) number of alive larvae, 3) number of ejected larvae, 4) number of pupae, and 5) total number of offspring. Syrup collection was also monitored to estimate energetic requirement for colony growth. Results revealed that the three commercial blends chemically differed in their amino acid contents, with those displaying higher concentrations (i.e., Salix sp. and A. deliciosa) accelerating microcolony development along with an increase of syrup collection. The advantages of rearing bumblebee commercial colonies using a pollen diet with an optimal amino acid content are discussed. © The Authors 2015. [less ▲]

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See detailSPECIFICITY OF CLASS I TAGATOSE 1,6-BISPHOSPHATE ALDOLASE ENHANCED TOWARD TAGATOSE 1,6-BISPHOPHATE
Freichels, Régine ULiege; Delmarcelle, Michaël ULiege; Colarusso, Andrea et al

Poster (2015, July)

Class I tagatose 1,6-bisphosphate aldolase catalyzes the reversible condensation of dihydroxyacetone phosphate and glyceraldehyde 3-phosphate to produce four D-ketohexoses 1,6-bisphosphate: D-tagatose 1,6 ... [more ▼]

Class I tagatose 1,6-bisphosphate aldolase catalyzes the reversible condensation of dihydroxyacetone phosphate and glyceraldehyde 3-phosphate to produce four D-ketohexoses 1,6-bisphosphate: D-tagatose 1,6-bisphosphate, D-fructose 1,6-bisphosphate, D-psicose 1,6-bisphosphate and D-sorbose 1,6-bisphosphate. These four sugars are diastereoisomers and differs from each other in their stereochemistry at carbons 3 and 4. The structure determination of three class I tagatose 1,6-bisphosphate aldolases has afforded new insight into their catalytic mechanism as well as their evolution. However, the determinant(s) that allow(s) the enzyme to be so unspecific at carbon 4 have remains unknown. The aim of this project is focused on the characterization of the structural features of tagatose 1,6-bisphosphate aldolases that determine the specificity of the enzyme towards tagatose versus fructose 1,6-bisphosphate (carbon C4). [less ▲]

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See detailPollen and nectar quality drive the major and minor floral choices of bumble bees
Somme, L.; Vanderplanck, Maryse ULiege; Michez, D. et al

in Apidologie (2015), 46(1), 92-106

To investigate whether floral resource quality impacts on bumble bee floral choices, we determined the pollen foraging constancy and floral choices of four bumble bee species commonly occurring in peaty ... [more ▼]

To investigate whether floral resource quality impacts on bumble bee floral choices, we determined the pollen foraging constancy and floral choices of four bumble bee species commonly occurring in peaty, wet meadows in South Belgium. We subsequently analyzed the chemical contents of pollen and nectar, as well as the nectar production of the major host plant species. Individuals of B. lapidarius and B. pascuorum collected high-quality pollen (i.e., having high essential amino acid and phytosterol content) on Comarum palustre and Trifolium pratense, whereas individuals of B. terrestris s.l. and B. hypnorum enlarged their diet breadth to less valuable pollen resources (Cirsium palustre and Valeriana repens). Since Persicaria bistorta and Comarum palustre offer abundant and concentrated nectar, these plant species might represent major nectar sources for bumble bee species in peaty, wet meadows. The present study demonstrated the role of pollen composition on differences in foraging strategies among bumble bee species. © 2014, INRA, DIB and Springer-Verlag France. [less ▲]

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See detailHow Does Pollen Chemistry Impact Development and Feeding Behaviour of Polylectic Bees?
Vanderplanck, Maryse ULiege; Moerman, Romain; Rasmont, Pierre et al

in PLoS ONE (2014), 9(1), 9

Larvae and imagos of bees rely exclusively on floral rewards as a food source but host-plant range can vary greatly among bee species. While oligolectic species forage on pollen from a single family of ... [more ▼]

Larvae and imagos of bees rely exclusively on floral rewards as a food source but host-plant range can vary greatly among bee species. While oligolectic species forage on pollen from a single family of host plants, polylectic bees, such as bumblebees, collect pollen from many families of plants. These polylectic species contend with interspecific variability in essential nutrients of their host-plants but we have only a limited understanding of the way in which chemicals and chemical combinations influence bee development and feeding behaviour. In this paper, we investigated five different pollen diets (Calluna vulgaris, Cistus sp., Cytisus scoparius, Salix caprea and Sorbus aucuparia) to determine how their chemical content affected bumblebee colony development and pollen/syrup collection. Three compounds were used to characterise pollen content: polypeptides, amino acids and sterols. Several parameters were used to determine the impact of diet on micro-colonies: (i) Number and weight of larvae (total and mean weight of larvae), (ii) weight of pollen collected, (iii) pollen efficacy (total weight of larvae divided by weight of the pollen collected) and (iv) syrup collection. Our results show that pollen collection is similar regardless of chemical variation in pollen diet while syrup collection is variable. Micro-colonies fed on S. aucuparia and C. scoparius pollen produced larger larvae (i.e. better mates and winter survivors) and fed less on nectar compared to the other diets. Pollen from both of these species contains 24-methylenecholesterol and high concentrations of polypeptides/total amino acids. This pollen nutritional “theme” seems therefore to promote worker reproduction in B. terrestris micro-colonies and could be linked to high fitness for queenright colonies. As workers are able to selectively forage on pollen of high chemical quality, plants may be evolutionarily selected for their pollen content, which might attract and increase the degree of fidelity of generalist pollinators, such as bumblebees. [less ▲]

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See detailStandardized protocol to evaluate pollen polypeptides as bee food source
Vanderplanck, Maryse ULiege; Leroy, B.; Wathelet, Bernard ULiege et al

in Apidologie (2014), 45(2), 192-204

Bees mainly rely on pollen for their protein resources. As these molecules are essential for numerous aspects of bee physiology like ovary development and larval growth, their quantification and ... [more ▼]

Bees mainly rely on pollen for their protein resources. As these molecules are essential for numerous aspects of bee physiology like ovary development and larval growth, their quantification and determination are crucial to evaluate diet quality. However, the term "protein" has been used to mention crude protein, total amino acids, or protein sensu stricto (i.e.; polypeptides of molecular weight >10,000 Da). In addition to this ambiguity, current methods for protein quantification suffer from bias due to nonprotein nitrogen and protein-to-protein variations. A reliable and nondestructive method to quantify the pollen polypeptides is then essential to estimate bee food source. The present paper aims (a) to detail such a protocol, (b) to evaluate its efficiency, and (c) to confront its results to those returned by traditional methods of protein estimation. Our protocol clearly overrides some bias of previous methods and is highly reliable. Results show the high variability in content of pollen polypeptides and suggest that the main part of the proteinaceous nitrogen is from oligopeptides. They also highlight that hand-collected pollen is a better matrice than pollen loads to estimate the polypeptides of pollen as bee food source. © 2013 INRA, DIB and Springer-Verlag France. [less ▲]

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See detailComparative study of alkaline extraction process of hemicelluloses from pear pomace
Rabetafika, Holy-Nadia ULiege; Bchir, Brahim ULiege; Blecker, Christophe ULiege et al

in Biomass & Bioenergy (2014), 61

Hemicelluloses were produced from pear pomace using direct alkaline extraction (sodium hydroxide and hydrogen peroxide) and two-step extraction with delignification pre-treatment (acidified sodium ... [more ▼]

Hemicelluloses were produced from pear pomace using direct alkaline extraction (sodium hydroxide and hydrogen peroxide) and two-step extraction with delignification pre-treatment (acidified sodium chlorite/sodium hydroxide). The aim of the study was to compare the extraction yield, composition and physicochemical characteristics of isolated hemicelluloses by size exclusion chromatography, FTIR and thermogravimetric analyses. Solid residues were analysed in order to evaluate the effect of processes on co-products (lignins and cellulose). Delignification of material (up to 995.4 g kg−1 of original lignins) during the direct alkaline hydrogen peroxide and two-step acidified sodium chlorite/sodium hydroxide processes improved the hemicellulose extraction yield attaining up to 945.3 g kg−1. Hemicelluloses were mainly composed of xylans (xylose/glucose ratio of 4.6–16.2) and had low lignin content (53.5–61.0 g kg−1 dry matter). Those from direct sodium hydroxide extraction were composed of xylans and glucans (xylose/glucose ratio of 1.5) with high content of lignins (149.3 g kg−1 dry matter). All isolated fractions were a mixture of polymers and oligomers with a molecular mass ranging from 1710 g mol−1 to 8 870 000 g mol−1. The two-step process gave the most pure cellulose residue (799.2 g kg−1 dry matter). According to results, the direct alkaline extraction with hydrogen peroxide was a promising process for the production of pure xylose-rich hemicelluloses from pear pomace solubilizing 802.2 g kg−1 of the original hemicelluloses but induced fragmentation of hemicelluloses. [less ▲]

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See detailLes Ressources Sauvages des Bois de Tapia (Uapaca bojeri) à Madagascar
Barsics, Fanny ULiege; Malaisse, François ULiege; Razafimanantsoa, Tsiresy et al

Poster (2013, October 19)

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See detailBiochemical and Structural studies of the type I tagatose bisphosphate aldolases
Freichels, Régine ULiege; Guarino, Carla; Delmarcelle, Michaël ULiege et al

Poster (2013, February 26)

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See detailNovel biosurfactants with biocontrol activity and low ecotoxicity
Jacques, Philippe ULiege; Bechet, M.; Castera-Guy, J. et al

Conference (2013)

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See detailProduction of a novel mixture of mycosubtilins by mutants of Bacillus subtilis.
Bechet, Max; Castera-Guy, Joany; Guez, Jean-Sebastien et al

in Bioresource technology (2013), 145

Using promoter exchange and gene knock-out strategies, two mutant strains, the so-called BBG116 and BBG125, were constructed from Bacillus subtilis wild-type strain ATCC 6633, a surfactin and mycosubtilin ... [more ▼]

Using promoter exchange and gene knock-out strategies, two mutant strains, the so-called BBG116 and BBG125, were constructed from Bacillus subtilis wild-type strain ATCC 6633, a surfactin and mycosubtilin producer. Compared to the parental strain, both mutants overproduced constitutively mycosubtilin, while BBG125 had lost the ability to synthesize surfactin. Surprisingly, BBG125 was found to produce about 2-fold less mycosubtilin than BBG116 despite an expected higher availability of the cytoplasmic precursors and cofactors pool for biosynthesis. Further physiological characterization of BBG125 also highlighted: (i) a strong influence of temperature on mycosubtilin biosynthesis in BBG125 with a maximal productivity observed at 22 degrees C, compared to 15 and 30 degrees C; (ii) substantial changes in fatty acid profiles and thereby in mycosubtilin isoforms, compared to the wild-type strain; and (iii) the presence of five novel mycosubtilin isoforms. The antifungal activities of the new mix were higher than or equal to those of purified isoforms. [less ▲]

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See detailCola pierlotii R.Germ. : étude de la composition chimique de la graine
Lognay, Georges ULiege; Wathelet, Bernard ULiege; Maesen, Philippe ULiege

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2013), 17(2), 309-311

This note reports the first analysis of the chemical composition of Cola pierlotii seed. It compares the recorded values with various literature data on Cola nitida and Cola acuminata that are the two ... [more ▼]

This note reports the first analysis of the chemical composition of Cola pierlotii seed. It compares the recorded values with various literature data on Cola nitida and Cola acuminata that are the two most used species or as agent flavor or as a precursor drugs. Cola pierlotii is characterized in particular by a high caffeine content up to 1.27%. [less ▲]

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See detailLes ressources sauvages comestibles des bois de tapias : caractérisation alimentaire des produits consommés
Barsics, Fanny ULiege; Malaisse, François ULiege; Lognay, Georges ULiege et al

in Verheggen, François; Bogaert, Jan; Haubruge, Eric (Eds.) Les vers à soie malgaches. Enjeux écologiques et socio-économiques. (2013)

Les bois de tapia (Uapaca bojeri) des Hautes Terres centrales de Madagascar regorgent de ressources sauvages comestibles utilisées par les populations locales dans leur alimentation régulière. Afin de ... [more ▼]

Les bois de tapia (Uapaca bojeri) des Hautes Terres centrales de Madagascar regorgent de ressources sauvages comestibles utilisées par les populations locales dans leur alimentation régulière. Afin de décrire ces apports en termes biochimiques, nous avons réalisé des analyses de contenu sur 7 ressources, soit 2 chenilles, 1 araignée et 4 champignons comestibles. Leurs taux de protéines, de lipides, ainsi que leur composition en acides aminés et acides gras ont été obtenus. Les résultats ont été exprimés dans l’absolu mais aussi en relation avec les indices alimentaires couramment utilisés pour définir les qualités protéiques et lipidiques des denrées. Ces analyses nous permettent de constater l’excellent apport protéique que représentent les Arthropodes, et mettent également en évidence leur qualité lipidique. Les résultats de ces analyses sont discutés en faisant le lien avec les recommandations de la FAO/OMS. [less ▲]

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See detailEffect of New Synthetic PEGylated Ferulic Acids in Comparison to Ferulic Acid and Commercial Surfactants on the Properties of Wheat Flour Dough and Bread
Nicks, Francois ULiege; Richel, Aurore ULiege; Dubrowski, Thomas ULiege et al

in Journal of the Science of Food and Agriculture (2013), 93(10), 2415-2420

BACKGROUND: Ferulic acid esterified with poly(ethylene glycol) with three different average molecular weights (200, 400 and 1000 g/mol) was studied in breadmaking. The effects of these antioxidants on the ... [more ▼]

BACKGROUND: Ferulic acid esterified with poly(ethylene glycol) with three different average molecular weights (200, 400 and 1000 g/mol) was studied in breadmaking. The effects of these antioxidants on the properties of wheat flour dough and bread were analyzed and compared with those obtained with ferulic acid and two commercial surfactants, diacetyl tartaric acid ester of mono- and diglycerides and sodium stearoyl lactylate. Farinographic and alveographic methods as well as weight, volume and bread firmness measurements were used for this purpose. <br /> <br />RESULTS: Such as ferulic acid, when the PEGylated derivatives were implemented in the dough (5000 ppm), it accelerated its breakdown and decreased its rheological properties. However, it allowed to avoid the important diminution of loaf volume observed when dough supplemented with ferulic acid was baked. That decrease in volume was related to the inhibition of the yeast (Saccharomyces cerevisae) by the unesterified ferulic acid. Moreover, two of the PEGylated ferulic acids even contributed to an increase of loaf volumes (5-6%) and demonstrated crumb softener properties. <br /> <br />CONCLUSION: The addition of ferulic acid in wheat flour dough caused the inhibition of the yeast, which resulted in decreased bread volume. That effect could be avoid by the esterification of ferulic acid with poly(ethylene glycol). [less ▲]

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See detailGreen synthesis and antioxidant activity of new PEGylated ferulic acids
Nicks, Francois ULiege; Richel, Aurore ULiege; Richard, Gaetan ULiege et al

in Tetrahedron Letters (2012), 53(19), 2402-2405

PEGylation of ferulic acid is described through a green esterification process involving poly(ethylene glycol) (PEG) with three different average molecular weights (200, 400 and 1000 g/mol) as both ... [more ▼]

PEGylation of ferulic acid is described through a green esterification process involving poly(ethylene glycol) (PEG) with three different average molecular weights (200, 400 and 1000 g/mol) as both reactive and solvent. Esterification with PEG400 and PEG1000 leads to original compounds soluble in all proportions in water. These new compounds display an antioxidant activity similar to that of ferulic acid. [less ▲]

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See detailChemical constraint of solitary bees in host-plant specialization
Vanderplanck, Maryse ULiege; Pinczewski, Azzédine; Wathelet, Bernard ULiege et al

Poster (2012)

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See detailEvolution of host-plant interactions in specialist bees
Vanderplanck, Maryse ULiege; Wathelet, Bernard ULiege; Wattiez, Ruddy et al

Conference (2012)

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See detailPollen content: what does it matter for polylectic bees?
Moerman, Romain; Vanderplanck, Maryse ULiege; Rasmont, Pierre et al

Conference (2012)

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See detailEvaluation of Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry for second-generation lignin analysis
Richel, Aurore ULiege; Vanderghem, Caroline ULiege; Simon, Mathilde ULiege et al

in Analytical Chemistry Insights (2012), 7

Matrix-Assisted Laser Desorption/Ionization time-of-flight (MALDI-TOF) mass spectrometry is evaluated as an elucidation tool for structural features and molecular weights estimation of some extracted ... [more ▼]

Matrix-Assisted Laser Desorption/Ionization time-of-flight (MALDI-TOF) mass spectrometry is evaluated as an elucidation tool for structural features and molecular weights estimation of some extracted herbaceous lignins. Optimization of analysis conditions, using a typical organic matrix, namely CHCA (alpha-cyano-4-hydroxycinnamic acid), in combination with alpha-cyclodextrine, allows efficient ionization of poorly soluble lignin materials and suppression of matrix-related ions background. Analysis of low-mass fragments ions (m/z 100-600) in the positive ion mode offers a “fingerprint” of starting lignins that could be a fine strategy to qualitatively identify principal interunit linkages between phenylpropanoid units. The molecular weights of lignins are estimated using size exclusion chromatography and compared to MALDI-TOF-MS profiles. Miscanthus (Miscanthus x giganteus) and Switchgrass (Panicum Virgatum L.) lignins, recovered after a formic acid/acetic acid/water process or aqueous ammonia soaking, are selected as benchmarks for this study. [less ▲]

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See detailEfficient microwave-promoted synthesis of glucuronic and galacturonic acid derivatives using sulfuric acid impregnated on silica
Richel, Aurore ULiege; Nicks, Francois ULiege; Laurent, Pascal ULiege et al

in Green Chemistry Letters & Reviews (2012), 5(2), 179-186

Monomode microwave-assisted syntheses of D-glucuronic and D-galacturonic acid derivatives are reported in the presence of a solid acid catalyst, consisting of sulfuric acid loaded onto silica. This ... [more ▼]

Monomode microwave-assisted syntheses of D-glucuronic and D-galacturonic acid derivatives are reported in the presence of a solid acid catalyst, consisting of sulfuric acid loaded onto silica. This approach affords a variety of surface-active monoglycosylated glucofuranosidurono-6,3-lactones and disubstituted galacturonic adducts in excellent yields in less than 10 min at 85 °C. This study illustrates the application of microwave heating mode, in combination with a cost-effective solid catalyst, as an efficient, selective and eco-friendly methodology in carbohydrate chemistry. [less ▲]

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