References of "Francis, Frédéric"
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See detailChanges in termites feeding diets for gut micro-organisms selection and further cultivation
Bauwens, Julien ULg; Brasseur, Catherine ULg; Matteotti, Christel ULg et al

Poster (2011, October 02)

Termites gut may overcome important dietary perturbations, initial diversity acting as key point buffering effects on host, although termites possess their own enzymatic system. Some artificial diets ... [more ▼]

Termites gut may overcome important dietary perturbations, initial diversity acting as key point buffering effects on host, although termites possess their own enzymatic system. Some artificial diets permitted a simplification of the lower termites gut symbiotic system, which could be used as first step in symbionts isolation and cultivation. Preliminary assay of cultivation actually gave encouraging results. Proteomic proved to be suitable tool to investigate such a complex system. Nevertheless, for some symbionts very few genes are sequenced, which should lead to more targeted proteomic studies. Protein chromatography will allow to split up the proteome and more accurate analysis. [less ▲]

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See detailInvestigation of mevalonate pathway in aphids
Vandermoten, Sophie ULg; Yu, Wenjuan; Chen, Julian et al

Poster (2011, October)

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See detailMicroorganisms from aphid honeydew attract natural enemies and tending ants
Verheggen, François ULg; Leroy, Pascal; Fischer, Christophe ULg et al

Conference (2011, August)

Aphids are some of the most serious pests of cultivated crops worldwide, causing major yield and economic losses. Previous works have demonstrated ants and natural enemies (including ladybeetles and ... [more ▼]

Aphids are some of the most serious pests of cultivated crops worldwide, causing major yield and economic losses. Previous works have demonstrated ants and natural enemies (including ladybeetles and hoverflies) to be able to use aphid volatile chemicals to locate aphid colonies. Here, we report the first isolation of a bacterium from the pea aphid Acyrthosiphon pisum honeydew, Staphylococcus sciuri, which produces kairomones used by the aphidophagous hoverfly Episyrphus balteatus and the Asian Ladybeetle Harmonia axyridis during their search for prey colonies. Some specific semiochemicals produced by S. sciuri were identified as attractants and ovipositional stimulants. Similarly, we have shown scouts of the aphid tending ant species, Lasius niger, to orientate their foraging behaviour toward an Aphis fabae infested plant and we have demonstrated that the odours released by this aphid honeydew were attractive for ant scouts. Again, bacteria were involved in the production of these honeydew semiochemicals. Interestingly, ant scouts were also able to discriminate honeydew odour from A. fabae (usually attended by L. niger) and A. pisum (unattendedby L. niger). Comparison of the volatile and bacteria composition of both aphid species honeydew were attended. [less ▲]

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See detailAphid - phytovirus interactions: investigation of virus binding mechanisms in insect vectors by lectin use and proteomic approach
Yattara, Almouner Ag Alhamis ULg; Véronique Genin, Eric Haubruge; Francis, Frédéric ULg

Poster (2011, July 11)

Aphids are well known for their role in virus transmission to host plant. In some cases, the virus is transmitted from plant to plant simply attached to the cuticule of the mouthparts or the forget. For ... [more ▼]

Aphids are well known for their role in virus transmission to host plant. In some cases, the virus is transmitted from plant to plant simply attached to the cuticule of the mouthparts or the forget. For other, circulative virus transmission based on virion internalization through the aphid gut followed by transfer to salivary glands and finally to next plant during aphid feeding is required. In both situations, presence of receptor components through the digestive tract of the aphids is needed for virus binding and further transmission to next plants even if not localized at the same place. In order to investigate the specific binding of virus on particular aphid receptors, two aphid-virus models were selected to be tested using several lectins showing differential sugar binding specificities. Virus transmission efficacy assays with Myzus persicae and potato virus but also Acyrthosiphon pisum and pea enation mosaic virus were performed using a range of lectins to assess the potential competition of lectins and virus. Some interesting lectins were found to reduce the virus transmission with a 2 fold factor showing potential use of lectin in virus spread control. The aphids were also investigated by a proteomic approach using a two Dimension-Differential in Gel Electrophoresis (2D-Dige) coupled with mass spectrometry to determine the aphid proteins involved in virus transmissions. Head or digestive tubes of aphids were collected and investigated for non persistant or persistant virus models respectively. Differential abilities of aphids to transmit the selected virus models are discussed in relation with lectin affinity specificity and investigated aphid proteins found to be involved in vector-virus interactions. The application of lectin as potential way to reduce virus transmission by aphids will also be developed. [less ▲]

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See detailMicroorganisms from Aphid Honeydew Attract and Enhance the Efficacy of Natural Enemies
Leroy, Pascal ULg; Sabri, Ahmed ULg; Heuskin, Stéphanie ULg et al

in Nature Communications (2011), 2

Aphids are one of the most serious pests of crops worldwide, causing major yield and economic losses. To control aphids, natural enemies could be an option but their efficacy is sometimes limited by their ... [more ▼]

Aphids are one of the most serious pests of crops worldwide, causing major yield and economic losses. To control aphids, natural enemies could be an option but their efficacy is sometimes limited by their dispersal in natural environment. Here we report the first isolation of a bacterium from the pea aphid Acyrthosiphon pisum honeydew, Staphylococcus sciuri, which acts as a kairomone enhancing the efficiency of aphid natural enemies. Our findings represent the first case of a host-associated bacterium driving prey location and ovipositional preference for the natural enemy. We show that this bacterium has a key role in tritrophic interactions because it is the direct source of volatiles used to locate prey. Some specific semiochemicals produced by S. sciuri were also identified as significant attractants and ovipositional stimulants. The use of this host-associated bacterium could certainly provide a novel approach to control aphids in field and greenhouse systems. [less ▲]

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See detailStand structure of mosquitoes (Diptera: Culicidae) in farms and establishment of a new potential vector of West Nile Virus for Belgium
Boukraa, Slimane ULg; Zimmer, Jean-Yves ULg; Simonon, Grégory ULg et al

Poster (2011, May 24)

Many Diptera, spread across the globe are likely to play a role in the transmission of various human and animal diseases. Mosquitoes in particular, give rise to various countries on research increasingly ... [more ▼]

Many Diptera, spread across the globe are likely to play a role in the transmission of various human and animal diseases. Mosquitoes in particular, give rise to various countries on research increasingly expanded and deepened. To better understand the structure of the Culicidae at cattle farms in Belgium and identify habitats favorable to the development of each species, a taxonomic inventory was conducted in 2008 and 2009 in ten different sites. They fall into five natural regions: Condroz, Ardenne, Fagne-Famenne, Lorraine and Compine. The collection of mosquitoes is based on sampling of larvae in 13 biotopes such as water troughs, tires, abandoned utensils and temporary puddles or not. The results of the morphotaxonomic study of the mosquitoes collected in the different study sites show the presence of five species of Culicidae divided into three genera, Anopheles, Culex and Culiseta. Of the 1843 individuals examined in 2009, Culex pipiens represents 79.98% of the total harvest. A new species is reported for Belgium, Culex modestus Ficalbi, 1890. This species is one of the most important from an epidemiological and medical-veterinary entomology, given its role in the transmission of West Nile and myxomatosis viruses. [less ▲]

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See detailPredominant effects of host plant species on Aphis gossypii aphid and Episyrphus balteatus hoverfly in a tritrophic approach
Poligui, René Noël ULg; Francis, Frédéric ULg; Haubruge, Eric ULg

Poster (2011, May 24)

The aphid Aphis gossypii Glover (Homoptera: Aphididae) is known as worldwide important pest. It causes serious injuries to crops, but is also able to feed on various cultivated and wild plants. Some ... [more ▼]

The aphid Aphis gossypii Glover (Homoptera: Aphididae) is known as worldwide important pest. It causes serious injuries to crops, but is also able to feed on various cultivated and wild plants. Some programs are developped to control this aphid. In many studies , hoverfy Episyrphus balteatus De Geer (Diptera : Syrphidae) is used as an efficient and aphid specific predator in biological control systems. In this work, we study cotton aphid choice plant discrimination, the effect of host plants on its developpment(fecondity and mortality), and the E.balteatus foraging and oviposition behavior according aphid host plants. Biologic parameters were observed using various plant combinations. E.balteatus behavioral observations were conducted using the Noldus Observer v.5.0. A.gossypii makes discriminant choice of his hosts, with better preference on Cucurbita pepo L. (Cucurbitaceae) and Capsicum annuum L. (Solanaceae). Dacryodes edulis (G. Don) H.J. Lam. (Burseraceae) and Vicia faba L. (Fabaceae) are the midle choice while Hibiscus sabdariffa L. (Malvaceae) is less chosen. A.gossypii develops easily on C.pepo, and weakly on C.anuum, H.sabdariffa,and V.faba. D. edulis induces very high mortality to A.gossypii. According to E. balteatus behavior, A. gossypii is more attractive when infesting C .pepo and V.faba, less on H. sabdariffa. While non infested , the hoverfly more attractive plant is V.faba. Our results highlited the importance of interactions between aphids and their host plants and the prey-host influence on a specific aphid predatory hoverfy. Suitable ways in correlation with this work are to investigated to complete this study and perform aphids biological control. [less ▲]

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See detailPredominant effect of host plant species on Aphis gossypii aphid and Episyrphus balteatus hoverfly in a tritrophic approach
Poligui, René Noël ULg; Francis, Frédéric ULg; Haubruge, Eric ULg

Conference (2011, May 24)

The aphid Aphis gossypii Glover (Homoptera: Aphididae) is known as worldwide important pest. It causes serious injuries to crops, but is also able to feed on various cultivated and wild plants. Some ... [more ▼]

The aphid Aphis gossypii Glover (Homoptera: Aphididae) is known as worldwide important pest. It causes serious injuries to crops, but is also able to feed on various cultivated and wild plants. Some programs are developped to control this aphid. In many studies , hoverfy Episyrphus balteatus De Geer (Diptera : Syrphidae) is used as an efficient and aphid specific predator in biological control systems. In this work, we study cotton aphid choice plant discrimination, the effect of host plants on its developpment(fecondity and mortality), and the E.balteatus foraging and oviposition behavior according aphid host plants. Biologic parameters were observed using various plant combinations. E.balteatus behavioral observations were conducted using the Noldus Observer v.5.0. A.gossypii makes discriminant choice of his hosts, with better preference on Cucurbita pepo L. (Cucurbitaceae) and Capsicum annuum L. (Solanaceae). Dacryodes edulis (G. Don) H.J. Lam. (Burseraceae) and Vicia faba L. (Fabaceae) are the midle choice while Hibiscus sabdariffa L. (Malvaceae) is less chosen. A.gossypii develops easily on C.pepo, and weakly on C.anuum, H.sabdariffa,and V.faba. D. edulis induces very high mortality to A.gossypii. According to E. balteatus behavior, A. gossypii is more attractive when infesting C .pepo and V.faba, less on H. sabdariffa. While non infested , the hoverfly more attractive plant is V.faba. Our results highlited the importance of interactions between aphids and their host plants and the prey-host influence on a specific aphid predatory hoverfy. Suitable ways in correlation with this work are to investigated to complete this study and perform aphids biological control. [less ▲]

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See detailStudy on the susceptibility of the bovine milk fat globule membrane proteins to enzymatic hydrolysis and organization of some of the proteins
Vanderghem, Caroline ULg; Francis, Frédéric ULg; Danthine, Sabine ULg et al

in International Dairy Journal (2011), 21(5), 312-318

Isolated milk fat globules were subjected to enzyme hydrolysis by a specific protease (trypsin) and a nonspecific protease (pronase E) to study the asymmetric arrangement of milk fat globule membrane ... [more ▼]

Isolated milk fat globules were subjected to enzyme hydrolysis by a specific protease (trypsin) and a nonspecific protease (pronase E) to study the asymmetric arrangement of milk fat globule membrane (MFGM) proteins. The remaining proteins on the globules after proteolysis were resolved by two-dimensional gel electrophoresis and identified by mass spectrometry. By this proteomic approach, the results confirmed different susceptibility of the MFGM proteins to proteolysis by enzymes. Butyrophilin and adipophilin were completely digested by trypsin and by pronase E, whereas lactadherin and xanthine dehydrogenase/oxidase were almost resistant to hydrolysis by trypsin and partially attacked by pronase E. Based on our results and recent bibliographic data, an up-dated model of the organization of some MFGM proteins is proposed and discussed. (c) 2011 Elsevier Ltd. All rights reserved. [less ▲]

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

Conference (2011, April 13)

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See detailThe semiochemically mediated interactions between bacteria and insects
Leroy, Pascal ULg; Sabri, Ahmed ULg; Verheggen, François ULg et al

in Chemoecology (2011), 21

In natural environment, semiochemicals are involved in many interactions between the different trophic levels involving insects, plants and hosts for parasitoids or prey for predators. These volatile ... [more ▼]

In natural environment, semiochemicals are involved in many interactions between the different trophic levels involving insects, plants and hosts for parasitoids or prey for predators. These volatile compounds act as messengers within or between insect species, inducing particular behaviours such as the localisation of a source of food, the orientation to an adequate oviposition site, the selection of a suitable breeding site and the localisation of hosts or prey. In this sense, bacteria have been shown to play an important role in the production of volatile compounds which ones act as semiochemicals. This review, focusing on the semiochemically-mediated interactions between bacteria and insects, highlights that bacterial semiochemicals act as important messengers for insects. Indeed, in most of the studies reported here, insects respond to specific volatiles emitted by specific bacteria hosted by the insect itself (gut, mouthparts, etc.) or present in the natural environment where the insect evolves. Particularly, bacteria from the families Enterobacteriaceae, Pseudomonaceae and Bacillaceae are involved in many interactions with insects. Because semiochemicals naturally produced by bacteria could be a very interesting option for pest management, advances in this field are discussed in the context of biological control against insect pests. [less ▲]

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See detailEtude préliminaire sur la biologie de la mineuse des fruits du safoutier Dacryodes edulis (G. Don.) H.J. Lam. ;Burseraceae) dans le Haut-Ogooué, Gabon.
Poligui, René Noël ULg; Mouaragadja, Isaac; Francis, Frédéric ULg et al

Poster (2011, April)

Le monitoring de l’entomofaune du safoutier (Dacryodes edulis (G. Don.) H.J.Lam. (Burseraceae) a été réalisé dans le Haut-Ogooué (Gabon) sur deux années successives (2009-2010), du mois d’août au mois ... [more ▼]

Le monitoring de l’entomofaune du safoutier (Dacryodes edulis (G. Don.) H.J.Lam. (Burseraceae) a été réalisé dans le Haut-Ogooué (Gabon) sur deux années successives (2009-2010), du mois d’août au mois décembre. Cette période correspond à la phase de production des fruits (safou) de cet arbre. Parmi les insectes nuisibles inventoriés, la mineuse (Lepidoptera ; Tortricidae) des safou constitue le ravageur majeur causant la chute de 25% des fruits sur grappes. La femelle pond sur les fruits dès la première semaine suivant leur nouaison. Les larves roses, à tête brune, creusent une petite galerie à l’intérieur du fruit dont elles dévorent le noyau. Avant la chute du fruit, la larve sort et nymphose au sol dans un cocon en soie, et l’imago, un petit papillon gris, émerge après deux semaines. Un Ichneumonidae a été reconnu comme parasitoïde de ses larves. Pseudopsondias microcarpa(A.Rich) Engl.(Anacardiaceae) a été identifié comme un autre arbre fruitier hôte de cet insecte. Des études ultérieures approfondiront la connaissance de ce ravageur et pourront permettre d’envisager une stratégie de lutte biologique contre cette mineuse. [less ▲]

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