References of "Francis, Frédéric"
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See detailLes porcheries : réservoirs des Culicoides (Diptera: Ceratopogonidae), vecteurs des virus de la Maladie de la Langue bleue et de Schmallenberg ?
Zimmer, Jean-Yves ULg; Saegerman, Claude ULg; Martinelle, Ludovic ULg et al

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

La fièvre catarrhale ovine (FCO) est une arbovirose qui affecte les ruminants domestiques et sauvages. Depuis sa récente apparition en Europe du Nord, cette épizootie virale a engendré des pertes ... [more ▼]

La fièvre catarrhale ovine (FCO) est une arbovirose qui affecte les ruminants domestiques et sauvages. Depuis sa récente apparition en Europe du Nord, cette épizootie virale a engendré des pertes économiques considérables. Les vecteurs biologiques du virus de la FCO sont des moucherons piqueurs appartenant au genre Culicoides (Diptera : Ceratopogonidae). Plusieurs campagnes de piégeage lumineux de ces moucherons adultes ont été réalisées précédemment en Belgique au sein d’exploitations bovines et ovines, mais aucune à l’intérieur des exploitations porcines. Cette étude vise donc à évaluer, au moyen de pièges lumineux, les populations de culicoïdes éventuellement présentes à l’intérieur de deux porcheries belges au cours de l’automne et de l’hiver 2008. La présence des espèces (potentiellement) vectrices du genre Culicoides a ainsi été mise en évidence à l’intérieur de ces bâtiments durant l’automne : 8 et 749 spécimens appartenant à 2 et 7 espèces ont ainsi respectivement été piégés au sein des porcheries, avec une majorité de femelles du complexe Obsoletus. L’ouverture des bâtiments semble fortement influencer leur présence. L’observation du statut alimentaire des femelles laisse supposer que ces moucherons sont susceptibles de se nourrir ou de pondre au sein des porcheries, même si le sang de porc n’a pas pu être identifié dans l’abdomen des femelles gorgées et que le lisier n’a pas révélé la présence de larves. Les porcs pourraient ainsi intervenir dans le maintien des populations d’espèces potentiellement vectrices du virus de la FCO, ou du nouveau virus dénommé virus Schmallenberg. [less ▲]

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See detailAssessing the foraging behavior of Agriotes sordidus wireworms in dual-choice olfactometers
Barsics, Fanny ULg; Fiers, Marie; Fauconnier, Marie-Laure ULg et al

in Communications in Agricultural and Applied Biological Sciences (in press)

The different steps of the foraging process of wireworms (Coleoptera: Elateridae) would be better understood if accurate and holistic information regarding the role of plant-produced chemicals ... [more ▼]

The different steps of the foraging process of wireworms (Coleoptera: Elateridae) would be better understood if accurate and holistic information regarding the role of plant-produced chemicals constituting their environment were available. Volatile organic compounds (VOC) play important roles in the interactions between plants and insects in many ecosystems, whether they take place aboveground or belowground. The roles of VOC are still relatively unknown for wireworms, and deserve attention. Here, we performed three experimentations with barley roots as baits. In the two first, we assessed the effect of chopped roots and fungus infected roots on the orientation of wireworms. In the third experiment, the larvae were confronted to both healthy and fungus infected roots. We discuss the results in terms of suitability of the olfactometers we designed for the investigation of olfaction in wireworms, and we provide suggestions to improve their use. [less ▲]

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See detailThe role of olfaction in wireworms: a review on foraging behavior and sensory apparatus
Barsics, Fanny ULg; Haubruge, Eric ULg; Francis, Frédéric ULg et al

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

Introduction Integrated management of wireworms (Coleoptera: Elateridae) depends upon approaches applied both above- and belowground, and over several spatial scales. While foraging, these soil pests use ... [more ▼]

Introduction Integrated management of wireworms (Coleoptera: Elateridae) depends upon approaches applied both above- and belowground, and over several spatial scales. While foraging, these soil pests use biotic and abiotic signals to orientate towards target plant organs. Development of efficient techniques for implementation in integrated strategies relies upon improved knowledge of this process. In particular, an important step consists of elucidating the role of volatile organic compounds (VOC), emitted by belowground plant organs, in wireworm chemical ecology. This would have a positive impact on push-pull strategies and varietal selection developed against these insects. Literature In this work, we summarized the available data regarding wireworm foraging behavior as well as variables that should be considered when studying the potential role of plant-produced volatile semiochemicals. This includes CO2 gradients and other host-related cues, temperature, relative humidity and soil moisture, and wireworm physiological stage. We also review what is known of the sensory apparatus of wireworms, since this is involved in every step of the foraging process. Conclusion Some baseline data for studying VOC related wireworm foraging behavior exists. Using it as a tool in applied entomology should result in discovery of the semiochemicals that underpin trophic interactions involving these pests. However, most of the key pest species are not fully described with regards to the parameters detailed here. Obtaining accurate information to fill the current knowledge gaps will be needed in order to devise new integrated management strategies. [less ▲]

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See detailEffets de deux associations culturales à base de blé sur les populations de pucerons (Homoptera: Aphididae) et d’auxiliaires aphidiphages: étude préliminaire menée en Chine
Chevalier Mendes Lopes, Thomas ULg; Bosquée, Emilie ULg; Honba, David et al

in Entomologie Faunistique = Faunistic Entomology (2014), 67

Crop associations have several advantages when plant species and crop production methods, including harvesting, are well selected. This preliminary study was conducted in the Shandong province (China) to ... [more ▼]

Crop associations have several advantages when plant species and crop production methods, including harvesting, are well selected. This preliminary study was conducted in the Shandong province (China) to better characterize the effect of wheat (Triticum aestivum L.)/oilseed rape (Brassica napus L.) and wheat/pea (Pisum sativum L.) associations on the aphid and aphidophagous beneficial populations. Aphids observed on wheat tillers were significantly more abundant in the pure stand of wheat during the two weeks prior to their population peak, compared with crop associations. Considering the aphidophagous beneficials, significantly more ladybirds were observed in the associations, compared with the pure stand during their abundance peak. Yellow pan traps were also used to assess the diversity and abundance of adult beneficial species. The parasitoid species Aphidius gifuensis (Ashmead) was prevalent. Among predators, Propylea japonica (Thunberg) and Harmonia axyridis (Pallas) were the most abundant species. This study contributes to better understand the potential of crop associations with wheat as a sustainable method to control aphid populations in this region of China. [less ▲]

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See detailBelowground Chemical Ecology: The Case of Wireworms
Barsics, Fanny ULg; Delory, Benjamin ULg; Delaplace, Pierre ULg et al

Conference (2014, December 13)

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See detailTuta absoluta (Lepidoptera: Gelechiidae) ability to localize and develop on wild and cultivated solanaceous plant species
Bawin, Thomas ULg; Dujeu, David; Fagan, Maud ULg et al

Conference (2014, December 13)

The tomato leafminer, Tuta absoluta (Lepidoptera: Gelechiidae), is a widespread invasive species damaging economically important cultivated solanaceous crop plants, including tomatoes and potatoes. Little ... [more ▼]

The tomato leafminer, Tuta absoluta (Lepidoptera: Gelechiidae), is a widespread invasive species damaging economically important cultivated solanaceous crop plants, including tomatoes and potatoes. Little is known about the ability of this microlepidoptera to encounter and develop on alternative wild and agricultural plant species. These plants could provide refuges and have to be identified for more efficient integrated management strategies. In the present study, we assessed the ability of T. absoluta to develop on wild (Solanum nigrum, Atropa belladonna, Datura stramonium) and cultivated (Solanum tuberosum) solanaceous plant species under laboratory conditions. Fitness tests were performed in Petri dishes by isolating single individuals with excised leaf from one of the host plants. We found that Solanum species allowed higher larval survivability and shorter development time (from egg to adult emergency) compared to the other plants. Two choice behavioral assays performed in flying tunnels (S. tuberosum versus another plant) revealed that adult distribution and female oviposition did not differ between Solanum species, which were preferred to the other tested plants. These results appeared to be consistent with survival rates and development times. Because larval survivability depends on the female’s oviposition choice, the hypothesis that host plant choice is influenced by plant volatile organic compounds has to be tested. It can be concluded that Solanum species remain the more suitable hosts for T. absoluta development among the tested plants. Other plant species could be opportunistically colonized with little incidence but care should be taken in these results as genetic variability in insects and plants, as well as plant physiological state, might have an impact on the pest survivabilty. [less ▲]

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See detailWood digestion in lower termites: multidisciplinary approaches based on differential feeding
Bauwens, Julien ULg; Brasseur, Catherine ULg; Tarayre, Cédric ULg et al

Poster (2014, December)

Termites digestive tract and hindgut especially still holds many secrets despites hundreds of years of research. The complexity of the symbiotic microbial community and the contrast of physio-chemical ... [more ▼]

Termites digestive tract and hindgut especially still holds many secrets despites hundreds of years of research. The complexity of the symbiotic microbial community and the contrast of physio-chemical environments found in lower termites paunch are potentially the key point to explain the efficiency of ligno-cellulose digestion. Contribution of advancing technologies accelerates the progress of our knowledge in this field. Here, we present multiple approaches combining old and recent techniques used to highlight the effect of ligno-cellulosic compounds on termite gut and the role of populations from the symbiotic microbial community. Termites Reticulitermes flavipes (Kollar) submitted to various artificial diets showed variations in flagellates populations profile and enzymatic activities. Differential protein expression was investigated using 2D-DIGE MALDI-TOF-TOF and 2D-LC-MS/MS using high resolution orbitrap analyzer. Results from both proteomic experiments tend to support each-other and bring complementary points of view. The gel-free analysis resulted in highly contrasted identification of enzymes involved in ligno-cellulose digestion and metabolism. Finally, differential feeding experiments leaded to in vivo selection of different symbiotic communities. These communities were characterized following some metabolism assays and allowed the cultivation of diverse microbial consortia using media closely related to the respective artificial diets. This work provides relevant data on termite and associated microbial community response to alimentary diets. [less ▲]

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See detailIncorporate agroecology within research : The on-going story of four young researchers
Hatt, Séverin ULg; Artru, Sidonie ULg; Boeraeve, Fanny ULg et al

in Broadening Scopes on Food, Squeezing Urban Hinterlands (2014, November 04)

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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 detailLa lutte contre les moustiques (Diptera: Culicidae): diversité des approches et application du contrôle biologique
Bawin, Thomas ULg; Seye, Fawrou; Boukraa, Slimane ULg et al

in Canadian Entomologist (2014)

Many mosquito (Diptera: Culicidae) species are zoonotic vectors responsible for numerous infectious diseases of medical and veterinary importance. Currently, changes in the vectors’ geographical ... [more ▼]

Many mosquito (Diptera: Culicidae) species are zoonotic vectors responsible for numerous infectious diseases of medical and veterinary importance. Currently, changes in the vectors’ geographical distribution induced chiefly by anthropogenic factors are accompanied by emerging and reemerging infectious diseases in Europe and North America. Since the advent of synthetic insecticides during the Second World War, mosquitoes are the object of considerably expanded and deepened research. In an integrated pest management context, means of control are now mainly classified as: (1) environmental management and physical control, (2) chemical control, (3) genetic control, and (4) biological control by means of entomophagous predators and entomopathogenic microorganisms. In this context, these last have significant potential because of their ability to infect and kill their host with more or less targeted selectivity. This article proposes to emphasize biological control among other techniques in mosquito control, and to assess the potential and the opportunities offered by entomopathogenic bacteria, viruses and fungi. Finally, their use as biopesticides is discussed. [less ▲]

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See detailHarmonia axyridis population study in agroecosystems
Vandereycken, Axel ULg; Fassotte, Bérénice ULg; Durieux, Delphine ULg et al

Poster (2014, October)

The Multicoloured Asian ladybird, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), is one of these species which was intentionally introduced for biological control and has spread from its native ... [more ▼]

The Multicoloured Asian ladybird, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), is one of these species which was intentionally introduced for biological control and has spread from its native range in Central and Eastern Asia to large parts of North and South America, Europe, and Africa. The decline of native species is linked to the spread and the aggressive behaviour of H. axyridis. From 2009, we evaluated the population densities of aphids predator and predator diversities, with a special focus on H. axyridis in agroecosystems of Wallonia (South of Belgium). First, field crops preferences of H. axyridis were determined. Later, changes linked to aphid’s predator populations over time were evaluated. Finally, H. axyridis population changes between two crop farming methods were also evaluated. Samplings performed in agroecosystems highlighted that the community of aphid's predator is composed of few dominant species: three coccinellids (Coccinella septempunctata L., P. quatuordecimpunctata L., and H. axyridis), one syrphid (Episyrphus balteatus De Geer), and one chrysopid (Chrysoperla carnea Stephens). We demonstrated that H. axyridis do not invade all crops at the same rate, maize and broad bean being more infested than wheat and potato at both larval and adult stages. Moreover, H. axyridis populations in maize have strongly increased from 2009 to 2011. Finally, we showed that organic farming do not contribute to increase the abundance of H. axyridis but leads to increase the total abundance of aphid’s natural enemies. [less ▲]

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See detailStudy of sex ratio and morphotypes of the Multicoloured Asian Ladybird, Harmonia axyridis Pallas in Belgian maize
Vandereycken, Axel ULg; Fassotte, Bérénice ULg; Barsics, Fanny ULg et al

Poster (2014, October)

Several insect species are known to have different morphotypes, an adaptation to heterogeneities in changing environments. This phenotypic plasticity could be a factor used by the Multicoloured Asian ... [more ▼]

Several insect species are known to have different morphotypes, an adaptation to heterogeneities in changing environments. This phenotypic plasticity could be a factor used by the Multicoloured Asian Ladybird, which is considered as an invasive species in Europe since its introduction in the 80’s. Harmonia axyridis has four major morphotypes: 2 melanic forms, conspicua and spectabilis; and 2 non-melanic, succinea and axyridis. In Belgium, only the three first are observed. Literature reports variations in morphotype frequencies, across native and introduced strains. These variations seem to be linked to climate (geographical and seasonal variation), with non-melanic forms being the most abundant in hot and arid climate. This study focused on the variation of morphotype abundance in H. axyridis according to season, field and gender. Adult ladybirds were caught from mid-July to mid-October 2012 into 5 maize fields. The proportions of observed morphotypes were compared according to the sampling season. The abundance of morphotypes was not significantly different through the fields; the observed ratios were 81.6%, 15% and 3.4% for succinea, spectabilis and conspicua respectively. Succinea was the most observed morphotype (χ2=755.8; P<0.001). The total number of collected males and females was the same with ratios of 48.2% and 51.8%: (χ2=0.93; P=0.33). The sex ratio was also not significantly different for each morphotype. There was no evolution of melanic and non-melanic form ratio according to the season, with 25.6% of melanic form in summer and 20.6% in autumn (χ2=1.22; P=0.27). Our results seem to show that morphotype adaptation according to the climate is not observed for Belgian ladybirds. [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 detailEvolution des populations de coccinelles indigènes et de l’espèce exotique, Harmonia axyridis Pallas, en Wallonie et en Région de Bruxelles-Capitale
Vandereycken, Axel ULg; Fassotte, Bérénice ULg; Durieux, Delphine ULg et al

Conference (2014, October)

Un inventaire des Coccinellidae provenant de la collection de l’unité d’Entomologie fonctionnelle et évolutive (ULg - Gembloux Agro-Bio Tech) a été réalisé sur une période s’étendant de 2001 à 2009. Cette ... [more ▼]

Un inventaire des Coccinellidae provenant de la collection de l’unité d’Entomologie fonctionnelle et évolutive (ULg - Gembloux Agro-Bio Tech) a été réalisé sur une période s’étendant de 2001 à 2009. Cette collection est essentiellement constituée de récoltes fournies par les étudiants de première Bachelier de Gembloux Agro-Bio Tech. A travers ce recensement, nous avons étudié l’évolution des espèces récoltées au sein de cette famille, en termes d’effectif relatif et de richesse spécifique. Notre étude s’est focalisée sur les données issues de Wallonie et de la Région de Bruxelles-Capitale, car trop peu de collectes ont été réalisées en Flandre. Parmi les individus identifiés, 27 espèces ont été observées, dont 21 appartiennent à la sous-famille des Coccinellinae, 2 à celle des Epilachninae et 4 à celle des Chilocorinae. La plupart des espèces sont communes à la Belgique. Cependant, Harmonia axyridis (Pallas 1773), espèce originaire du sud-est de l’Asie, a été introduite sur le territoire belge en 1997. Cette coccinelle exotique a fait son apparition dans les collectes de 2002 et son effectif ne cesse d’augmenter au fil des années prospectées. En parallèle à cette augmentation, une diminution de la richesse spécifique, ainsi que de l’effectif relatif d’Adalia bipunctata (L. 1758), de Propylea quatuordecimpunctata (L. 1758) et de Psyllobora vigintiduopunctata (L. 1758), est observée. [less ▲]

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See detailLarval development sites of the main Culicoides species (Diptera: Ceratopogonidae) in northern Europe and distribution of coprophilic species larvae in Belgian pastures
Zimmer, Jean-Yves ULg; Brostaux, Yves ULg; Haubruge, Eric ULg et al

in Veterinary Parasitology (2014), 205(3-4), 676-686

Some Culicoides species of biting midges (Diptera: Ceratopogonidae) are biological virus vectors worldwide and have indeed been associated with outbreaks of important epizoonoses in recent years, such as ... [more ▼]

Some Culicoides species of biting midges (Diptera: Ceratopogonidae) are biological virus vectors worldwide and have indeed been associated with outbreaks of important epizoonoses in recent years, such as bluetongue and Schmallenberg disease in northern Europe. These diseases, which affect domestic and wild ruminants, have caused considerable economic losses. Knowledge of substrates suitable for Culicoides larval development is important, particularly for the main vector temperate species. This study, realized during two years, aimed to highlight the larval development sites of these biting midge species in the immediate surroundings of ten Belgian cattle farms. Moreover, spatial distribution of the coprophilic Culicoides larvae (C. chiopterus and C. dewulfi) within pastures was studied with increasing distance from farms along linear transects (farm–pasture–woodland). A total of 4347 adult specimens belonging to 13 Culicoides species were obtained by incubation of 2131 soil samples belonging to 102 different substrates; 18 of these substrates were suitable for larval development. The Obsoletus complex (formed by two species) was observed in a wide range of substrates, including silage residues, components of a chicken coop, dung adhering to walls inside stables, leftover feed along the feed bunk, a compost pile of sugar beet residues, soil of a livestock trampling area, and decaying wood, while the following served as substrates for the other specimens: C. chiopterus, mainly cow dung; C. dewulfi, cow dung and molehill soil; C. circumscriptus, algae; C. festivipennis, algae and soil in stagnant water; C. nubeculosus, algae and silt specifically from the edge of a pond; C. punctatus, mainly wet soil between silage reserves; C. salinarius, algae; and C. stigma, algae and wet soil between silage reserves. We also recorded significantly higher densities of coprophilic larvae within pastures in cow dung located near forests, which is likely due to the localization of potential hosts; the presence of these larvae within cow dung is, however, uninfluenced by relative distance from farms. A better knowledge of the microhabitats of Culicoides biting midges and their spatial distribution may allow the development of targeted species-specific vector control strategies, and may help to prevent the creation of new larval development sites. [less ▲]

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See detailIsolation and cultivation of xylanolytic and cellulolytic Sarocladium kiliense and Trichoderma virens from the gut of the termite Reticulitermes santonensis
Tarayre, Cédric ULg; Bauwens, Julien ULg; Brasseur, Catherine ULg et al

in Environmental Science & Pollution Research (2014)

The purpose of this work was the isolation and cultivation of cellulolytic and xylanolytic microorganisms extracted from the gut of the lower termite Reticulitermes santonensis. Microcrystalline cellulose ... [more ▼]

The purpose of this work was the isolation and cultivation of cellulolytic and xylanolytic microorganisms extracted from the gut of the lower termite Reticulitermes santonensis. Microcrystalline cellulose (with and without lignin) and beech wood xylan were used as diets instead of poplar wood in order to select cellulose and hemicellulose-degrading fungi. The strain Sarocladium kiliense (Acremonium kiliense) CTGxxyl was isolated from the termites fed on xylan, while the strain Trichoderma virens CTGxAviL was isolated from the termites fed on cellulose (with and without lignin). Both molds were cultivated in liquid media containing different substrates: agro-residues or purified polymers. S. kiliense produced maximal β-glucosidase, endo-1,4-β-D-glucanase, exo-1,4-β-D-glucanase and endo-1,4-β-D-xylanase activities of 0.103, 3.99, 0.53, and 40.8 IU/ml, respectively. T. virens produced maximal β-xylosidase, endo-1,4-β-D-glucanase, exo-1,4-β-D-glucanase, and endo-1,4-β-D-xylanase activities of 0.38, 1.48, 0.69, and 426 IU/ml. The cellulase and the xylanase of S. kiliense, less common than T. virens, were further investigated. The optimal activity of the xylanase was observed at pH 9–10 at 60 °C. The cellulase showed its maximal activity at pH 10, 70 °C. Zymography identified different xylanases produced by both molds, and some fragment sizes were highlighted: 35, 100, and 170 kDa for S. kiliense and 20, 40, 80, and 170 kDa for T. virens. In both cases, endo-1,4-β-D-xylanase activitieswere confirmed through mass spectrometry. [less ▲]

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See detailFrom landscape infrastructures to conservation biological control. Why the concept of functional diversity may be useful?
Hatt, Séverin ULg; Francis, Frédéric ULg

Scientific conference (2014, September 19)

Landscape infrastructures are numerous. They can be hedgerows, woodlands or wildflower strips. They are known to provide ecosystem services such as reducing soil erosion and nutrient leaching or support ... [more ▼]

Landscape infrastructures are numerous. They can be hedgerows, woodlands or wildflower strips. They are known to provide ecosystem services such as reducing soil erosion and nutrient leaching or support biodiversity conservation. They may also help to biologically control pests. But conclusions of research papers are not unanimous about the positive effect of wildflower strips to control pests in fields. The cause may be the type of flower mixes sown in fields. In this context, the concept of functional diversity may be useful to constitute flower mixes that better enhance biological control. [less ▲]

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See detailDesign of a fungal biofilm reactor for recombinant protein production from Aspergillus oryzae
Zune, Quentin ULg; Delepierre, Anissa ULg; Bauwens, Julien ULg et al

Poster (2014, September 07)

Fungi are microorganisms exhibiting high secretive power of various metabolites and have the ability to perform post-translational modifications during protein synthesis. In the field of fermentation ... [more ▼]

Fungi are microorganisms exhibiting high secretive power of various metabolites and have the ability to perform post-translational modifications during protein synthesis. In the field of fermentation industry, they are ideal hosts for secondary metabolites and recombinant protein production. At the industrial-scale, equipments usually required for solid-state or submerged fermentation of filamentous fungi have demonstrated their limitations in terms of productivity, mass transfers or products recovery (1, 2). Recently, fungal biofilm reactors were designed to combine advantages from submerged and solid-state culture and reveal their usefulness for greater secondary metabolites production relative to submerged culture conditions (3). In our work, we propose the design of a fungal biofilm reactor for a recombinant protein production from an Aspergillus oryzae strain containing a GFP reporter gene system under the control of a promoter specifically induced in solid-state conditions. The fungal biofilm reactor is composed of a metal structured packing, having the function of inert support for biofilm growth, immerged or aspersed by a liquid medium. Whereas recombinant protein production is not significantly different at the flask-scale between submerged and biofilm conditions, productivity is higher in the submerged conditions at the bioreactor-scale. Presence of recombinant proteins entrapped in the biofilm matrix highlights a diffusion constraint and a lower mass transfer in our fungal biofilm reactor. However, persistence of a free liquid biomass of low viscosity and fungal biomass retention on the support are attractive for the implementation of a continuous process in our fungal biofilm reactor. Further studies will consider a 2-D proteomic comparison of the extracellular medium from fungal biofilm reactor and submerged culture conditions in order to better understand proteins secretion and identify over-expressed proteins in biofilm conditions. [less ▲]

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