References of "Francis, Frédéric"
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See detailLivestock farms in Belgium shelter they the mosquitoes (Diptera, Culicidae) potentially vectors of arboviruses?
Boukraa, Slimane ULg; Zimmer, Jean-Yves ULg; Simonon, Grégory et al

Poster (2012, August 23)

Although no major arbovirus which mosquitoes are responsible for its transmission has been recorded in Belgium in recent decades, environment and climate change, current and future, could favor the ... [more ▼]

Although no major arbovirus which mosquitoes are responsible for its transmission has been recorded in Belgium in recent decades, environment and climate change, current and future, could favor the emergence of vector-borne diseases in the country, by inducing changes on Culicidae populations. This study aims to determine the potential importance of agricultural environments, and especially livestock farms, to welcome and favor the proliferation of certain species of mosquito responsible for transmission of arboviruses. A taxonomic inventory was conducted in 2008 (III, VI and X) and 2009 (V and IX) in ten cattle farms, and in 2010 (X) in ten stables located in Belgium. The harvest of mosquitoes is based on larval sampling at the level of 14 biotopes such as water troughs, used tires, abandoned utensils and temporary puddles or not. The morphotaxonomic study of larvae and genitalia has allowed to identify eight species in 18 study stations. These are Anopheles claviger Meigen, 1804 ; A. maculipennis s.l. Meigen, 1818 ; Culiseta annulata Schrank, 1776 ; Cs. morsitans Theobald, 1901 ; Culex modestus Ficalbi, 1889 ; Cx. torrentium Martini, 1925 ; Cx. territans Walker, 1856 and Cx. pipiens s.l. L., 1758. Of the 1843 individuals examined in 2009, Cx. pipiens s.l. represents 79.98% of the total harvest; however, Cx. modestus represents only 0.92%. Used tires form the most favorable habitat for larval development of Culicidae. Therefore, despite the low diversity of mosquito observed within the livestock environments, they represent a significant risk for the reproduction of some potential vectors of arboviruses. In addition, some larval habitats constitute very favorable sites for proliferation of mosquito, causing a real problem of nuisance for animals of farms. [less ▲]

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See detailPathogenicity test of the fungus Aspergillus clavatus on aphid Acyrthosiphon pisum (Aphididae)
Seye, Fawrou; Bawin, Thomas ULg; Delvigne, Frank ULg et al

Poster (2012, August 19)

Pea aphid is a pest of many cultivated and wild plants, but also a vector of several viral diseases. To control this pest, the most widely used methods are physical, chemical and more recently an ... [more ▼]

Pea aphid is a pest of many cultivated and wild plants, but also a vector of several viral diseases. To control this pest, the most widely used methods are physical, chemical and more recently an integrated approach that includes biological control. With the use of pathogenic agents against insects, the use of entomopathogenic fungi is one of the most promising. The present study demonstrated the possibility of using an entomopathogenic fungus Aspergillus clavatus against aphids. In laboratory conditions (8/16 photoperiod, average temperature 25°C), the insects were in contact with different concentrations ranging from 10^2 to 10^4 spores/cm2 deposited on filter paper in Petri dishes, or applied directly to young plants with doses ranging from 10^4 to 10^6 spores/ml. In 24 hours, mortality was 0 to 31.5% in Petri dishes. For treatment plants, the cumulative mortality in 5 days was 55 to 79%. Microscopic observations showed that the aphids were infected by contact and fungus has a mycosis effect. From these preliminary results, investigations should be made to study the action of the fungus on the reproduction of aphids. Therefore, A. clavatus could be introduced along with other fungi found in the literature as a biological control agent against aphids. [less ▲]

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See detailVolatile organic compounds released by barley roots attract wireworms
Barsics, Fanny ULg; Fiers, Marie ULg; Francis, Frédéric ULg et al

Poster (2012, August)

Wireworms, the soil dwelling larvae of click beetles, are pests of many crops worldwide. Alternatives to insecticide treatments are needed for integrated management strategies. Our work consists in ... [more ▼]

Wireworms, the soil dwelling larvae of click beetles, are pests of many crops worldwide. Alternatives to insecticide treatments are needed for integrated management strategies. Our work consists in elucidating the role of barley (Hordeum vulgare L.) root-emitted volatile organic compounds (VOC) on the orientation behaviour of Agriotes sordidus Illiger wireworms (Fig. 1). Using dual choice olfactometers, we have evaluated the attractiveness of baits ranging from barley roots themselves to one isolated root-emitted volatile organic compound. [less ▲]

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See detailRisk of introduction of alphaviruses responsible for American equine encephalitides in Belgium
De la Grandière de Noronha Cotta, Maria Ana ULg; Dal Pozzo, Fabiana ULg; Francis, Frédéric ULg et al

Poster (2012, August)

Arthropod-borne viruses are a threat for human and animal healths in regards with their dissemination out of their endemic area. The arboviruses reviewed here belong to the family Togaviridae genus ... [more ▼]

Arthropod-borne viruses are a threat for human and animal healths in regards with their dissemination out of their endemic area. The arboviruses reviewed here belong to the family Togaviridae genus Alphavirus and are small enveloped positive sense RNA viruses. They are considered as exotic equid pathogens in Europe and can cause severe diseases in humans in the context of an epidemic. Arboviruses have complex epidemiologic features characterised by interactions between viruses, vectors, reservoir or susceptible host species, and environment. A bibliographic search was performed to identify the mean factors that influenced past outbreaks in America and the presence of potential vectors/vertebrate hosts that could play a role in the transmission cycle in Belgium. Three equine arboviruses, currently considered as the main current threats of emergence/introduction in Western Europe, were chosen as model for this study: Eastern equine encephalitis virus (EEEV), Western equine encephalitis virus (WEEV) and Venezuelan equine encephalitis virus (VEEV). In conclusion, taking into consideration the globalisation (increase of international exchanges) and climate warming, the analysis of the different features of the arbovirus cycles are essential to a balanced risk expertise in the Belgian context. Research supported by the Belgium Federal Public Service, Health, Food Chain Safety and Environment. [less ▲]

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See detailTermites artificially-fed on unusual diet and resulting enzymatic switches
Bauwens, Julien ULg; Tarayre, Cédric ULg; Matteotti, Christel et al

Poster (2012, August)

Wood-feeding termites as Reticulitermes santonensis generally feed on cellulose, hemicelluloses and lignin. However, these opportunistic insects are also able to degrade other carbohydrates, such as ... [more ▼]

Wood-feeding termites as Reticulitermes santonensis generally feed on cellulose, hemicelluloses and lignin. However, these opportunistic insects are also able to degrade other carbohydrates, such as starch. The production of putative endogenous α - amylase has been previously shown in R. flavipes, as the disappearance of the major symbiotic flagellates from the hindgut. Here, we compared enzymatic activities (CMCase, MCCase, xylanase, amylase, α- and β-glucosidase) between different fractions of the digestive tract of starch-, cellulose-, and wood-fed termites. Main compounds of the artificial diets, namely starch or MCC, resulted in differential enzymatic activity. Even the substitution of wood by artificial diets itself seemed to induce changes in enzymatic activities, regardless of the main substrate in the diet, as we observed strong midgut α-glucosidase activity only for artificially-fed termites. Preliminary assays to isolate and characterize enzymes were performed using proteomic methods. [less ▲]

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See detailBreeding sites of main Bluetongue virus vectors in Belgian cowshed
Zimmer, Jean-Yves ULg; Saegerman, Claude ULg; Losson, Bertrand ULg et al

Poster (2012, August)

Bluetongue (BT) is an emerging vectorborne disease of ruminants that was reported in August 2006 in northern Europe. Since 2007, BT virus (BTV) serotype 8 continued its spread across Europe and caused ... [more ▼]

Bluetongue (BT) is an emerging vectorborne disease of ruminants that was reported in August 2006 in northern Europe. Since 2007, BT virus (BTV) serotype 8 continued its spread across Europe and caused considerable economic losses. This observation indicates possible overwintering of the vector from year to year. The biological vectors of BTV are biting midges of the genus Culicoides. Breeding sites of bluetongue vector species have been found near farms (e.g. silage residues) and in neighboring meadows (e.g. cattle dung) but never inside sheds. We conducted a study in five cattle farms in Belgium during February–October 2008. Three samplings were performed and each soil sample collected inside cowsheds was incubated to enable adult midges to emerge. Among 15 soil biotopes sampled, only one showed the emergence of adult Culicoides biting midges: dried dung adhering to walls inside animal enclosures and resulting to the partial removal of used animal litter. It was a breeding site for the C. obsoletus/C. scoticus complex. Physico-chemical characteristics showed that midges of this complex are more prevalent in soil samples with a high carbon:nitrogen (C:N) index. So Culicoides biting midges are able to complete their life cycle in animal enclosures. We identified a breeding site for the primary BTV vector in a cowshed in northern Europe. These observations could explain the persistence of BTV from year to year despite fairly harsh winters. Hygienic measures on farms could reduce biting midges populations and so improve efficacy of vaccination campaigns against BT in Europe. [less ▲]

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See detailProteomics of aphid salivary proteins
Francis, Frédéric ULg; De Pauw, Edwin ULg; Vandermoten, Sophie ULg et al

Conference (2012, August)

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See detailEffect of reduced water supply on aphid physiology : A proteomic approach on peach-aphid interaction
Verdugo, Jaime; Lacroze, Jean-philippe; Sauge, Marie-Hélène et al

Poster (2012, August)

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See detailFeeding humans with edible insects : actual state and perspectives in Belgium and Europe
Sablon, Ludovic ULg; Alabi, Taofic; Drugmand, Didier et al

Poster (2012, August)

In future decades, world population will grow up to 9 billion of people and we will be confronted to a lack of nutritive resources. We will not continue to produce proteins with our conventional livestock ... [more ▼]

In future decades, world population will grow up to 9 billion of people and we will be confronted to a lack of nutritive resources. We will not continue to produce proteins with our conventional livestock as beef, poultry or pig. It will therefore look to other sources and edible insects are one of these solutions. Indeed, more than 2000 species of edible insects were actually consumed by 3000 ethnic groups in the world. In undernourished populations, entomophagy is essential to relieve deficiencies in proteins, fatty acids and some vitamins. In Europe, we have acquired sedentary habits and we have lost our ancestral harvesting and hunting traditions. It is the reason of disinterest for edible insects and entomophagy was considered as a "barbarian" food habit. Facing food challenges of tomorrow, it is important to sensitize industrialized populations and to reintroduce edible insects in our plates and habits. The first step is to overcome neophobia of food products. Our studies focused on different insect preparations and on perception of entomophagy by different age classes. Globally, our first results indicated that entomophagy was accepted by belgian consumers but the more difficult for them is to taste the first time. These results confirmed neophobia for this type of food products and thus the importance of positive informations and education for acceptance of entomophagy. [less ▲]

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See detailCharacterization of Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) overwintering sites
Fassotte, Bérénice ULg; Durieux, Delphine ULg; Francis, Frédéric ULg et al

Poster (2012, August)

Originally introduced as a biological control agent, the multicoloured Asian ladybeetle, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), has become an invasive pest throughout Europe and North ... [more ▼]

Originally introduced as a biological control agent, the multicoloured Asian ladybeetle, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), has become an invasive pest throughout Europe and North America in the last few years. Although its effectiveness to control aphid and coccid populations was impressive, some negative impacts appeared rapidly, notably on human health. Indeed, to protect themselves from cold temperatures, H. axyridis individuals move inside dwellings and buildings and form large aggregations in concealed portions of structures to overwinter. The aggregating beetles are responsible for some annoyances due to, on one hand, the number of individuals inside homes and, on the other hand, the hemolymph secretions they release when they are disturbed, which can cause allergic reactions. In order to highlight the specific features of infested houses, we investigated a large number of overwintering sites in Wallonia between 2007 and 2011. These sites were characterized through a survey sent to homeowners confronted to invasion problems. This survey was mainly focused on a general description of the infested house (type, colour, infested floor(s), building material), the orientation of the colonized rooms and the position of the beetles’ cluster. The collected data indicate that H. axyridis preferentially selects isolated brick houses with red or white fronts to take shelter. Aggregations are mostly located at the first floor, essentially inside south, west or southwest oriented rooms. Furthermore, ladybeetles generally gathered into wooden windows frames facing south, west or southwest and to a lesser extent, in the upper corners of walls presenting the same orientation. All these results contribute to improve the knowledge on the aggregative behaviour of H. axyridis and could promote the development of more specific and efficient management methods to prevent massive infestations into dwellings, such as artificial shelters or trapping systems located at the outside of buildings. [less ▲]

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See detailBehavioral response of Harmonia axyridis towards their footprints according to their physiological state
Durieux, Delphine ULg; Fassotte, Bérénice ULg; Vanderplanck, Maryse et al

Poster (2012, August)

In order to survive cold, the multicolored Asian ladybeetle, Harmonia axyridis (Pallas), aggregates inside dwellings during winter. It has been recently highlighted that overwintering H. axyridis ... [more ▼]

In order to survive cold, the multicolored Asian ladybeetle, Harmonia axyridis (Pallas), aggregates inside dwellings during winter. It has been recently highlighted that overwintering H. axyridis individuals lay an area marking while walking, which is used by conspecifics to locate aggregation sites. These footprints are made-up of hydrocarbons, comprising both saturated and unsaturated homologues. However, it has not been demonstrated whether this “following area marking” behavior is specific to the overwintering individuals. The work presented herein was oriented to the study of the chemical evolution of these footprints according to the physiological state of H. axyridis. Monthly GC-MS analyses revealed that the area marking contained a greater amount of di-unsaturated compounds when laid by overwintering ladybeetles, suggesting the great importance of these chemicals in the ladybeetles aggregation process. In the second instance, behavioral investigations conducted in a Y-shaped glass tube were performed to assess (1) the evolution of H. axyridis behavior towards their footprints and (2) whether this behavioral modification is due to an evolution of the ladybeetles sensitivity or rather to an evolution of the area marking attractiveness. The results revealed that only the overwintering individuals follow their area marking, and that this behavior is linked to the ladybeetle physiological state rather than to the chemical profile of the marking biomolecules. [less ▲]

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See detailIdentification of bacteria community associated with earthworm gut
Lemtiri, Aboulkacem ULg; Alabi, Taofic; Bodson, Bernard ULg et al

Poster (2012, July 26)

The role of earthworms in soil fertility and transformation of organic waste was regulary cited to be of first importance. Associated to these macro-invertebrates, a large diversity of micro-orgnisms are ... [more ▼]

The role of earthworms in soil fertility and transformation of organic waste was regulary cited to be of first importance. Associated to these macro-invertebrates, a large diversity of micro-orgnisms are found indirectly in their closed environment or directly in their gut. Functional aspects of these interactions and symbiosis in relation with soil characteristics and fertility rates are poorly developed. Here, the micro-organisms diversity and potential related functions of earthworm gut were investigated using a proteiomic approach for both protein and micro-organism identifications. Microbial community investigation was detected by proteomic approach based on bidimensional electrophoresis coupled with mass spectrometry using Matrix Assisted Laser Desorption Ionisation – time of flight (Maldi-Tof). Diversity of gut associated bacterial communities was discussed. Indeed, application of particular crop production practices such as crop residue management at the field level could regulate the gut bacterial communities in earthworm but also microbials in soils. Agricultural systems had to consider the microbial and associated organisms in the soil to enhance fertlility and crop production in sustainable ways. [less ▲]

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See detailRole of aphid endosymbionts on virus transmission efficiency
Bosquée, Emilie ULg; Haubruge, Eric ULg; Francis, Frédéric ULg

Poster (2012, July 26)

A large number of phytoviruses are transmitted exclusively by aphids in a circulative manner after transport by the aphid haemolymph to the salivary glands before transmission to new plant short time ... [more ▼]

A large number of phytoviruses are transmitted exclusively by aphids in a circulative manner after transport by the aphid haemolymph to the salivary glands before transmission to new plant short time later. Some proteins, synthesized in aphids by symbiotic bacteria, are hypothesized to bind to virus particles in the haemolymph, to help transfer inside the aphid without any problem and finally promoting viral transmission efficiency. Multiple endosymbionts commonly coexist in the same host insects. The endosymbiotic bacterial partners of aphids fall into two categories: the obligate “primary” symbiont such as Buchnera sp. found in almost all aphids and the facultative “secondary” bacteria that are not always present. Particular associations between aphids and both Buchnera sp. and secondary symbionts well documented according to adaptation to host plant specificity. In contrast, the impact of specific associations between Buchnera and other facultative secondary endosymbionts on the virus transmission is less well understood. In order to understand the role of some ensymbionts associated to the primary one in the PeMV (Pea enation Mosaic Virus) transmission, several Acyrthosiphon pisum clones presenting different patterns of endosymbionts (Buchnera-Serratia, Buchnera-Spiroplasma, Buchnera-Rickettsia), were used in PeMV efficiency transmission assays on broad bean. The PeMV occurrence in plants was tested by enzyme- linked immunosorbent assay technique (ELISA). The higher virus transmission was found when Serratia bacteria was present in the pea aphid. The occurrence of Serratia endosymbiotic bacteria was concluded to be very important in the PeMV transmission. Finally, the aphid symbiont pattern modulation was discussed in multitrophic approach and potential control of aphid and associated dispersion of viral diseases. [less ▲]

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See detailImpact of Myzus persicae infestation on the volatile emission of Arabidopsis thaliana Col-0.
Hien, Truong Thi Dieu ULg; Delaplace, Pierre ULg; Francis, Frédéric ULg et al

Poster (2012, July 22)

Being members of complex communities, plants often emit a wide range of volatile organic compounds to defend themselves against insect invasions. Although many studies exist on insect-induced plant ... [more ▼]

Being members of complex communities, plants often emit a wide range of volatile organic compounds to defend themselves against insect invasions. Although many studies exist on insect-induced plant volatile emission, most of them either compare the influences of various herbivore species on one plant species or the impact of a given herbivore on several host plant species. Moreover, informations related to the influence of insect density as well as the infestation duration are still needed. Here, we showed that a sucking insect – Myzus persicae (green peach aphid) induced the volatile emission from Arabidopsis thaliana Columbia wild-type (A.thaliana Col-0) under laboratory conditions based on results obtained by solid-phase micro-extraction coupled with gas chromatography - mass spectrometry (SPME-GC/MS). The released volatile blend was discussed in relation to related biosynthesis pathways and functions. These included terpenoids, green leaf volatiles, alcohols and isothiocyanate. The qualitative and overall proportion of volatile components differed depended on the number and residence duration of aphids on leaves. By studying the effects of sucking insect stresses to plant, we not only aim to contribute to the fundamental understanding of the emission of volatile components in the interaction between plants and pests, but also to provide standardised and easy to use assays to assess A.thaliana volatile changes according to cross stresses, including both biotic and abiotic ones in ongoing experiments. [less ▲]

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See detailImpact of soil management on earthworm diversity according to differential plowing and plant residue incorporation
Lemtiri, Aboulkacem ULg; Alabi, Taofic; Zirbes, Lara ULg et al

Poster (2012, July 02)

Earthworms are largely distributed in terrestrial ecosystems and their abundance and diversity in soils are significantly affected by biotic (macro- and micro-organisms) and abiotic factors: soil ... [more ▼]

Earthworms are largely distributed in terrestrial ecosystems and their abundance and diversity in soils are significantly affected by biotic (macro- and micro-organisms) and abiotic factors: soil properties (pH, texture, structure…); agricultural management system and climate change. Here, tillage effect of earthworm population combined with crops residual management was investigated and correlated with soils properties. From wheat experimental field plots, the diversity of earthworm according to the field crop management was assessed. Application of particular crop production practices such as the integration of different levels of crop residues, diverse parts of wheat straws, at the field level regulate earthworm diversity and population abundance. Indeed, tillage reduced earthworm population with a 35% rate also corresponding to changes in soil properties. Agricultural practices had to be adapted to include consideration on macro-invertebrate abundance and diversity to maintain efficient soil fertility and allow sustainable crop production [less ▲]

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See detailSelection and cultivation of hydrolytic microorganisms extracted from the digestive tract of the termite Reticulitermes santonensis (3DV.1.55)
Tarayre, Cédric ULg; Bauwens, Julien ULg; Matteotti, Christel ULg et al

Poster (2012, June 21)

Biofuel production can be based on the use of fermentable substrates issued from the hydrolysis of lignocellulosic biomass stemming from agricultural residues and by-products. However, such substrates are ... [more ▼]

Biofuel production can be based on the use of fermentable substrates issued from the hydrolysis of lignocellulosic biomass stemming from agricultural residues and by-products. However, such substrates are not easy to degrade. Enzymes (cellulases, xylanases, etc.) can be used for this purpose and pre-treatments can increase their action by providing more available extremities. The digestive tract of the termite Reticulitermes santonensis contains various microorganisms (bacteria, molds, protists) able to degrade the wood components. These microorganisms act as consortia, leading to a better hydrolysis than in the cow rumen. Our purpose is the isolation of microorganisms from termite guts in order to evaluate their potential for hydrolysis of lignocellulosic materials. This approach led us to isolate and to study a bacteria (Bacillus sp.) displaying a xylanase activity, a mold (Aspergillus sp.) displaying a cellulase activity and a chrysophyte (protist) displaying an amylase activity. [less ▲]

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