Pour de nombreux endoparasitoïdes ichneumonides, le succès parasitaire dépend de leur association avec un polydnavirus symbiote. Les particules virales, produites exclusivement dans les ovaires, sont injectées dans la chenille du lépidoptère au moment de l’oviposition. L’expression des gènes viraux dans les tissus infectés induit des altérations importantes dans la croissance, le développement et la réponse immunitaire de l’hôte, ce qui permet le développement de la progéniture du parasitoïde. Les gènes vankyrines constituent une famille multigénique que l’on retrouve dans tous les génomes de polydnavirus séquençés jusqu’à présent. Ils codent pour des protéines homologues aux facteurs IkappaBs, inhibiteurs des facteurs de transcription Rel/NF-kB, dont le représentant le plus étudié chez les insectes est la protéine Cactus de Drosophila melanogaster. Les vankyrines possèdent un domaine ARD constitué de quatre répétitions de type ankyrines qui, chez les IkBs sont essentielles pour leur interaction avec les facteurs NF-kB. Mais contrairement aux IkB cellulaires, les vankyrines n'ont pas les domaines de régulation nécessaires à la dissociation du complexe NF-kB/IkB : elles formeraient donc un complexe irréversible avec les NF-kB, ce qui aurait pour conséquence d’empêcher les NF-kB de se fixer sur leurs sites kB et donc empêcherait l’expression de gènes impliqués dans la réponse immunitaire et/ou le développement de l’hôte parasité. Nous avons identifié neuf gènes vankyrines dans le génome du polydnavirus HdIV, présent chez Hyposoter didymator [Hyménoptère : Ichneumonidae], un endoparasitoïde larvaire de certaines noctuelles, appartenant notamment au genre Spodoptera spp. L’analyse spatio-temporelle des vankyrines de HdIV a mis en évidence l’expression largement prédominante de la vankyrine Hd27-vank1 au cours du parasitisme des larves de S. frugiperda par H. didymator. Pour tenter de comprendre le rôle de Hd27-vank1, nous avons produit un baculovirus recombinant exprimant la protéine virale. Nous avons alors mesuré les effets de l’expression de la protéine virale sur la viabilité des larves de S. frugiperda et des cellules Sf9 infectées avec le baculovirus recombinant. Nous présenterons les résultats obtenus au cours de ce congrès.

Stenoma decora Zeller, 1854 (Lepidoptera: Depressariidae), is considered a pest of the cacao tree, Theobroma cacao L. (Malvaceae), causing direct losses by damaging the fruits. In this study, we searched for parasitoids of Stenoma decora. Caterpillars were obtained from fruits and stems in commercial plantations of T. cacao in Mutuípe, Bahia, Brazil, and reared in laboratory. Here we describe the new species Neocardiochiles tropicalis sp. nov. (Hymenoptera: Braconidae) as a parasitoid of S. decora. Parasitised individuals can be readily identified, as the parasitoid kills the prepupa and produces a light-coloured silk cocoon in place of the host’s dark, sclerotised pupal exuviae. This is the first species of the Neocardiochiles recorded in Brazil, and the southernmost record for the genus so far. The presence of this parasitoid in a commercial crop area provides an important context for biological control, representing a new perspective for the management of S. decora.

Eldana saccharina est un lépidoptère foreur de la canne à sucre qui provoque une baisse qualitative et quantitative de la production de sucre et de biomasse dans de nombreux pays africains producteurs. La compagnie sucrière sénégalaise (CSS) travaille depuis plusieurs années sur ce problème et a déployé un système de surveillance des populations de ce ravageur tant dans les champs de canne par des systèmes de comptage des dégâts au niveau des tiges que par un suivi des adultes grâce à la mise en place de pièges lumineux fonctionnant à l'énergie solaire, fruit d'une collaboration étroite avec l'unité de recherches Agroécologie et Intensification Durables des Cultures Annuelles (AIDA) du CIRAD. Cet article fait le point sur ces méthodes de contrôle et propose des stratégies de protection agroécologique pour réduire les dégâts de cet insecte, en collaboration avec le CIRAD : réduction des doses d'azote appliquées dans les parcelles de canne, surveillance des systèmes pratiques et monitoring d'irrigation, évaluation des ennemis naturels du ravageur dans la zone et une meilleure gestion du drainage des zones basses, afin d'éviter les situations de stress hydrique des plants qui engendrent les infestations. En matière de piège lumineux, la CSS est actuellement en train de déployer une centaine de pièges lumineux supplémentaires sur son périmètre sucrier, afin d'augmenter les captures d'adultes d'E.saccharina et ainsi empêcher un accroissement des populations et des dégâts surtout en période de saison des pluies. D'autres solutions à moyen terme sont aussi proposées et discutées dans le contexte climatique sahélien de la CSS.

The genus Sciomesa Tams & Bowden (Lepidoptera: Noctuidae: Noctuinae: Apameini: Sesamiina) is a predominantly Afrotropical group of stemborer moths whose convoluted taxonomic history needs to be clarified. In this study, a comprehensive examination of specimens in collections was carried out in a complementary manner with molecular analyses, resulting in the following changes: (i) 12 new Sciomesa species are described: S. lalokeli n. sp. and S. metiminko n. sp. from Ethiopia; S. elgonensis n. sp., S. nigra n. sp. and S. simillima n. sp. from Kenya; S. umvoti n. sp. from South Africa; S. iboya n. sp., S. lilomwi n. sp., S. makete n. sp., S. njombe n. sp. and S. tanganyika n. sp. from Tanzania; S. kalinzu n. sp. from Uganda; (ii) four species are reinstated as valid species: three of them, S. constantini Laporte stat. rev., S. etchecopari Laporte stat. rev. and S. mirifica Laporte stat. rev., were previously synonymized with S. mesophaea (Hampson) while S. congitae (Laporte) stat. rev. was previously synonymized with S. boulardi (Laporte); (iii) two species are synonymized: S. minuscula (Laporte) n. syn., which was previously synonymized with S. boulardi, is a synonym of S. congitae, and S. franciscae Laporte n. syn. is a synonym of S. mesophaea; (iv) one species, Sesamia punctipennis Krüger stat. rev., which was transferred to the Sciomesa genus, is removed from the genus Sciomesa and temporarily reinstated to the genus Sesamia Guenée pending a new combination. A supplemental description for 12 previously described species is also provided: S. boulardi, S. bua Moyal et al., S. constantini, S. etchecopari, S. excelsa (Laporte), S. gnosia Moyal et al., S. mesophaea, S. congitae, S. mirifica, S. renibifida Berio, S. scotochroa (Hampson) and S. venata Fletcher. Host-plant records are provided for 10 Sciomesa species, confirming a pattern of phylogenetic niche conservatism on Poales plants in the Cyperaceae family. Phylogenetic and molecular species delimitation analyses were carried out on a multimarker (four mitochondrial and two nuclear genes) molecular dataset encompassing 63 Sciomesa specimens, 24 species belonging to other genera of Sesamiina, and one representative of the sister subtribe Apameina. This sampling also includes the three Malagasy species (S. betschi Viette, S. janthina Viette and S. oberthueri Viette) whose status is debated. The resulting phylogenetic framework provides the most complete picture of the evolutionary relationships of the genus Sciomesa, and results of topological tests provide further support for removing S. betschi and S. janthina from the genus Sciomesa pending new combinations. The results of molecular species delimitation analyses also overwhelmingly support the species status of the Sciomesa species sampled, even for S. mesophaea, a species with a very wide range in the Afrotropics. These analyses also reveal the existence of up to three potential new species, whose status cannot be ascertained because the sequenced individuals were either extracted at a larval stage or correspond to specimens whose genitalia were not studied when their legs were collected.

This paper presents a quantization algorithm for complex-valued rank-one matrices that exploits rescaling-invariances of the problem to obtain better results than round-to-nearest strategy. This algorithm is also used as a building block for an heuristic strategy to quantize complex-valued butterfly-structured sparse matrices appearing for example in the fast Fourier transform. Compared to element-wise round-to-nearest quantization, the number of bits is reduced by 30% the number of bits for a given precision on butterfly matrices, while maintaining a polynomial time complexity in the dimension of the matrices.

Cushion plants, which dominate nival ecosystems, are known to host a large diversity of plant, microbe, and animal life. However, a comprehensive assessment of this diversity is still lacking, particularly with regard to invertebrate soil fauna. In this study, we sampled soil beneath cushion plants in various climatic and geological conditions throughout the French Alps. Our results demonstrate that cushion plants host a remarkably high abundance and diversity of invertebrates, with some individual cushions hosting nearly 400 specimens belonging to 15 different families. Across all samples, 8845 specimens were found. The taxonomic diversity is particularly notable, with groups such as Collembola, Acari, and Nematoda, as well as Gastropoda, Diptera, Coleoptera, Hymenoptera, and Hemiptera. In total, 44 different families were identified. In particular, our findings show that cushion plants not only function as habitats for adult invertebrates, but also as site for the egg laying and larval development of several insect groups, including Diptera, Hemiptera, and Lepidoptera. In addition, different species of cushion plant tend to host distinct invertebrate communities, which makes them a key driver spatial variation in invertebrate populations. However, the factors determining the alpha diversity of invertebrates assemblages in nival environments remain unclear. Overall, our results emphasize the key role of cushion plants in maintaining biodiversity in the nival vegetation belt.

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Abstract Cu-Cr based alloys with a high Cr content are widely used as electrical contact materials in vacuum interrupters due to their good combination of electrical, thermal, and mechanical properties. During a current interruption process in a vacuum, the establishment of an electrical arc results in a severe local thermal input onto the contact material surface. Few studies have closely investigated the microstructural evolution during this phenomenon as well as the Cu-Cr alloy properties evolution. This study reports the microstructural, electrical conductivity, and hardness evolution of a Cu-25Cr (25 wt%Cr) solid state sintered alloy as electrical contact before and after successive current interruptions. Electron scanning and optical microscopy show that this microstructural evolution is a result of a complex phenomenon. Local and heterogeneous thermal conditions take place resulting in significant microstructural evolution. The resulting microstructure is related to out-of-equilibrium solidification conditions. Electrical conductivity is decreased by half in the whole thermally affected zone by the electrical arc and hardness is multiplied by three to four times.

Cathepsin C (CatC) is a highly conserved tetrameric lysosomal cysteine dipeptidyl aminopeptidase. The best characterized physiological function of CatC is the activation of pro-inflammatory granule-associated serine proteases. These proteases are synthesized as inactive zymogens containing an N-terminal pro-dipeptide, which maintains the zymogen in its inactive conformation and prevents premature activation, which is potentially toxic to the cell. The activation of serine protease zymogens occurs through cleavage of the N-terminal dipeptide by CatC during cell maturation in the bone marrow. In vivo data suggest that pharmacological inhibition of pro-inflammatory serine proteases would suppress or attenuate deleterious effects mediated by these proteases in inflammatory/auto-immune disorders. The pathological deficiency in CatC is associated with Papillon-Lefèvre syndrome (PLS). The patients however do not present marked immunodeficiency despite the absence of active serine proteases in immune defense cells. Hence, the transitory pharmacological blockade of CatC activity in the precursor cells of the bone marrow may represent an attractive therapeutic strategy to regulate activity of serine proteases in inflammatory and immunologic conditions. A variety of CatC inhibitors have been developed both by pharmaceutical companies and academic investigators, some of which are currently being employed and evaluated in preclinical/clinical trials.