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54 results on '"Diversité, Génomes et Interactions Microorganismes-Insectes"'

1. Immune Response of Harmonia axyridis (Coleoptera: Coccinellidae) Supports the Enemy Release Hypothesis in North America

Author

Michel Brehélin, Guy Boivin, Pierre-Alain Girard, Daniel Coderre, Annabelle Firlej, Université de Montréal (UdeM), Diversité, Génomes et Interactions Microorganismes-Insectes, Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2), Québec City, Agriculture and Agri-Food [Ottawa] (AAFC), Natural Sciences and Engineering Research Council of Canada, and Quebec Minister of Education

Subjects
hemocyte, Harmonia axyridis, [SDV]Life Sciences [q-bio], UNITED-STATES, Zoology, Biology, Parasitoid, Immune system, VIRUS-LIKE PARTICLES, PSEUDOPLUSIA-INCLUDENS, Hemolymph, Botany, parasitoid, IN-VIVO, Innate immune system, BEAUVERIA-BASSIANA, fungi, HEMOCYTES, INSECT PARASITOIDS, biology.organism_classification, Dinocampus coccinellae, DROSOPHILA-MELANOGASTER, Insect Science, Ultrastructure, encapsulation, Coccinellidae, LADY BEETLE COLEOPTERA, DINOCAMPUS-COCCINELLAE
Abstract

The multicolored Asian lady beetle, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), is an invasive species in North America that has a low susceptibility to indigenous natural enemies. We investigated the role of the immune system of H. axyridis in its resistance to North American population of the hymenopteran parasitoid Dinocampus coccinellae Schrank. An ultrastructural study of adult H. axyridis hemocytes under electron and light microscopy identified five different cellular types: plasmatocytes, granular hemocytes I, granular hemocytes II, oenocytoids, and spherule cells. Only granular hemocytes II and plasmatocytes are involved in the nodulation of bacteria and encapsulation of parasitoid eggs. Injection of Sephadex beads in H. axyridis adults induces an innate immune response and results in complete encapsulation of ≈28% of the beads after 24 h and 81% after 5 d. When H. axyridis was parasitized by D. coccinellae, we observed a decrease in the encapsulation response, and this pattern was inversely related to the number of parasitoid eggs in the H. axyridis hemolymph. The injection of polydnaviruses by D. coccinellae females and the multiple target hypotheses could both explain the encapsulation rate decreasing with increasing parasitoid egg load. Our results suggest that the immune system of H. axyridis could favor its escape from internal developing natural enemies indigenous to North America.

Published
2012
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2. Genomics of adaptation to host-plants in herbivorous insects

Author

Jean Peccoud, Pierre Nouhaud, Endrick Guy, Réjane Streiff, Jean-Christophe Simon, Emmanuelle d'Alençon, Akiko Sugio, Emmanuelle Jacquin-Joly, Julie Jaquiéry, Institut de Génétique, Environnement et Protection des Plantes (IGEPP), Institut National de la Recherche Agronomique (INRA)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-AGROCAMPUS OUEST, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Diversité, Génomes et Interactions Microorganismes-Insectes, Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2), Institut d'écologie et des sciences de l'environnement de Paris (iEES Paris), Institut National de la Recherche Agronomique (INRA)-Sorbonne Université (SU)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Origine, structure et évolution de la biodiversité (OSEB), Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Traitement et Communication de l'Information (LTCI), Télécom ParisTech-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS), Institut d'écologie et des sciences de l'environnement de Paris (IEES), Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Ecosystèmes, biodiversité, évolution [Rennes] (ECOBIO), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Centre National de la Recherche Scientifique (CNRS), AGROCAMPUS OUEST-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National de la Recherche Agronomique (INRA), Ecologie, Evolution, Symbiose (EES), Ecologie et biologie des interactions (EBI), Université de Poitiers-Centre National de la Recherche Scientifique (CNRS)-Université de Poitiers-Centre National de la Recherche Scientifique (CNRS), Diversité, Génomes & Interactions Microorganismes - Insectes [Montpellier] (DGIMI), Université de Montpellier (UM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de la Recherche Agronomique (INRA), This work received supports from ANR Speciaphid (ANR-11-BSV7-005-01) to JCS, ANR Ada-Spodo (ANR-12-BSV7-0004-01) to EA, ANR Bugspit (ANR-13-JSV7-0012-01) to AS and ANR Adapt-Ome (ANR-13-BSV7-0012-01) to RS., ANR-11-BSV7-0005,SPECIAPHID,Génétique de l'adaptation trophique et mécanismes d'isolement reproducteur chez les pucerons(2011), ANR-12-BSV7-0004,ADA-SPODO,Déterminisme moléculaire de l’adaptation écologique et de la spéciation chez deux variants du lépidoptère Spodoptera frugiperda(2012), ANR-13-JSV7-0012,Bugspit,Mécanismes moléculaires impliqués dans la spécialisation des pucerons à leurs hôtes(2013), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Recherche Agronomique (INRA), Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM), ANR-12-BSV7-0004,ADA-SPODO,Déterminisme moléculaire de l'adaptation écologique et de la spéciation chez deux variants du lépidoptère Spodoptera frugiperda(2012), and Institut National de la Recherche Agronomique (INRA)-Université de Rennes (UR)-AGROCAMPUS OUEST

Subjects
Insecta, media_common.quotation_subject, Population, Genomics, Insect, salivary genes, Biology, Biochemistry, Host-Parasite Interactions, Hemiptera, Genetics, Animals, Herbivory, Mating, detoxification, education, Molecular Biology, chemosensory genes, media_common, education.field_of_study, Herbivore, mechanisms, plant cues, [SDV.GEN]Life Sciences [q-bio]/Genetics, Host (biology), Ecology, fungi, food and beverages, plant–insect interactions, General Medicine, Reproductive isolation, 15. Life on land, Plants, Adaptation, Physiological, Lepidoptera, Adaptation, [SDE.BE]Environmental Sciences/Biodiversity and Ecology
Abstract

International audience; Herbivorous insects represent the most species-rich lineages of metazoans. The high rate of diversification in herbivorous insects is thought to result from their specialization to distinct host-plants, which creates conditions favorable for the build-up of reproductive isolation and speciation. These conditions rely on constraints against the optimal use of a wide range of plant species, as each must constitute a viable food resource, oviposition site and mating site for an insect. Utilization of plants involves many essential traits of herbivorous insects, as they locate and select their hosts, overcome their defenses and acquire nutrients while avoiding intoxication. Although advances in understanding insect-plant molecular interactions have been limited by the complexity of insect traits involved in host use and the lack of genomic resources and functional tools, recent studies at the molecular level, combined with large-scale genomics studies at population and species levels, are revealing the genetic underpinning of plant specialization and adaptive divergence in non-model insect herbivores. Here, we review the recent advances in the genomics of plant adaptation in hemipterans and lepidopterans, two major insect orders, each of which includes a large number of crop pests. We focus on how genomics and post-genomics have improved our understanding of the mechanisms involved in insect-plant interactions by reviewing recent molecular discoveries in sensing, feeding, digesting and detoxifying strategies. We also present the outcomes of large-scale genomics approaches aimed at identifying loci potentially involved in plant adaptation in these insects.

Published
2015
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3. Des mécanismes différents sont employés par deux virus de plante pour organiser la transmission

Author

Drucker, Martin, ProdInra, Migration, Biologie et Génétique des Interactions Plante-Parasite (UMR BGPI), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro), and Institut National de Recherche Agronomique (INRA). UMR Diversité, Génomes et Interactions Microorganismes-Insectes (1333).

Subjects
[SDV] Life Sciences [q-bio], [SDV]Life Sciences [q-bio], ComputingMilieux_MISCELLANEOUS
Abstract

National audience

Published
2015

4. Génomique et plasticité génomique chez les bactéries pathogènes d’insecte, Photorhabdus et Xenorhabdus

Author

Gaudriault, Sophie, Diversité, Génomes et Interactions Microorganismes-Insectes, Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2), Université Montpellier 2 (Sciences et Techniques), and Estelle Jumas-Bilak

Subjects
[SDV.SA]Life Sciences [q-bio]/Agricultural sciences, hdr, [SDE.BE]Environmental Sciences/Biodiversity and Ecology
Published
2013

5. Immunité des insectes vs Complexes bactério-helminthiques entomopathogènes

Author

Duvic, Bernard, Diversité, Génomes et Interactions Microorganismes-Insectes, Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2), Université Montpellier 2 (Sciences et Techniques), and Gérard Lefranc

Subjects
nématode entomopathogène, interaction, insectes, lutte biologique, [SDE.BE]Environmental Sciences/Biodiversity and Ecology
Published
2012

6. Génomique comparative dans le genre Xenorhabdus : l'espèce X. Poinarii caractérisée par un pouvoir pathogène atténué et un génome de petite taille

Author

Ogier, Jean-Claude, Pages, Sylvie, Tailliez, Patrick, Bisch, Gaëlle, Teyssier, Corinne, Carrere, Sebastien, Medigue, Claudine, Rouy, Zoé, Givaudan, Alain, Gaudriault, Sophie, Diversité, Génomes et Interactions Microorganismes-Insectes, Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2), Ecologie des systèmes marins côtiers (Ecosym), Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS), Unité mixte de recherche interactions plantes-microorganismes, Institut National de la Recherche Agronomique (INRA)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDV]Life Sciences [q-bio], [SDV.BV]Life Sciences [q-bio]/Vegetal Biology, ComputingMilieux_MISCELLANEOUS
Abstract

National audience

Published
2012

7. Identification de facteurs de virulence chez la bactérie pathogène d'insecte Xenorhabdus :de la comparaison génomique au phénotype d'un candidat

Author

Bisch, Gaëlle, Ogier, Jean-Claude, Gaudriault, Sophie, Diversité, Génomes et Interactions Microorganismes-Insectes, and Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2)

Subjects
[SDV.SA]Life Sciences [q-bio]/Agricultural sciences, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, ComputingMilieux_MISCELLANEOUS
Abstract

National audience

Published
2012

8. La protéine FliZ de Xenorhabdus nematophila : un régulateur pléiotropique

Author

Lanois, Anne, Gaudriault, Sophie, Jubelin, Grégory, Gouzy, Jerome, Severac, Dany, Rialle, Stéphanie, Longin, Cyrille, Givaudan, Alain, Diversité, Génomes et Interactions Microorganismes-Insectes, Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2), Unité de Microbiologie (MIC), Institut National de la Recherche Agronomique (INRA), Unité mixte de recherche interactions plantes-microorganismes, Institut National de la Recherche Agronomique (INRA)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Institut de Génomique Fonctionnelle - Montpellier GenomiX (IGF MGX), Institut de Génomique Fonctionnelle (IGF), Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées, Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS), and Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDV.SA]Life Sciences [q-bio]/Agricultural sciences, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2012

9. Identification de nouveaux facteurs de virulence chez la bactérie pathogène d’insecte Xenorhabdus par génomique comparative et fonctionnelle

Author

Bisch, Gaëlle, Gaudriault, Sophie, Diversité, Génomes et Interactions Microorganismes-Insectes, and Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2)

Subjects
[SDV.SA]Life Sciences [q-bio]/Agricultural sciences, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, ComputingMilieux_MISCELLANEOUS
Abstract

National audience

Published
2012

10. Four Amino Acids of an Insect Densovirus Capsid Determine Midgut Tropism and Virulence

Author

Morena Casartelli, Cecilia Multeau, Ilaria Castelli, Mylène Ogliastro, Aurélie Perrin, Rémy Froissart, Diversité, Génomes et Interactions Microorganismes-Insectes, Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2), InVivo AgroSolut, Université Montpellier 2 - Sciences et Techniques (UM2), Maladies infectieuses et vecteurs : écologie, génétique, évolution et contrôle (MIVEGEC), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad), Università degli Studi di Milano [Milano] (UNIMI), Diversité, Génomes & Interactions Microorganismes - Insectes [Montpellier] (DGIMI), Université de Montpellier (UM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de la Recherche Agronomique (INRA), French Association Nationale Recherche Technologie, In vivo AgroSolutions from the Union In vivo group, and French Institut National de la Recherche Agronomique

Subjects
Models, Molecular, [SDV]Life Sciences [q-bio], viruses, Immunology, Amino Acid Motifs, Molecular Sequence Data, Virulence, Biology, Spodoptera, Virus Replication, JUNONIA-COENIA DENSOVIRUS, Microbiology, PATHWAY, 03 medical and health sciences, Virology, INFECTION, Animals, Densovirus, Amino Acid Sequence, Tropism, 030304 developmental biology, chemistry.chemical_classification, 0303 health sciences, 030302 biochemistry & molecular biology, fungi, Midgut, 3. Good health, Amino acid, Virus-Cell Interactions, GENOME, Intestines, Viral Tropism, chemistry, Viral replication, Capsid, Insect Science, Tissue tropism, VIRUS, Capsid Proteins, HOST-RANGE
Abstract

Densoviruses are insect parvoviruses that are orally infectious for Lepidoptera . To assess the mechanisms underlying their specificity and their virulence, we investigated the role of eight candidate residues in the densovirus capsid. We showed that the substitutions of four amino acids were associated with decreased virulence due to a decreased ability to cross the host midgut epithelium, without an effect on viral replication in other tissues.

Published
2012
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11. Disentangling dispersal, vicariance and adaptive radiation patterns: a case study using armyworms in the pest genus Spodoptera (Lepidoptera: Noctuidae)

Author

Pascaline Dumas, Anne-Laure Clamens, Andrew Mitchell, Jean-François Silvain, Dorothy Prowell, Bruno Le Ru, Gael J. Kergoat, Fabien L. Condamine, Centre de Biologie pour la Gestion des Populations (UMR CBGP), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Université de Montpellier (UM)-Institut de Recherche pour le Développement (IRD [France-Sud])-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Louisiana State University (LSU), Institut de Recherche pour le Développement, Partenaires INRAE, Australian Museum [Sydney], Diversité, Génomes et Interactions Microorganismes-Insectes, Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2), Centre de Mathématiques Appliquées - Ecole Polytechnique (CMAP), École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), and Institut de Recherche pour le Développement (IRD)

Subjects
0106 biological sciences, Genetic Speciation, [SDV]Life Sciences [q-bio], Biogeography, Biology, Late Miocene, Spodoptera, Poaceae, 010603 evolutionary biology, 01 natural sciences, Lepidoptera genitalia, 03 medical and health sciences, bayesian relaxed clock, Adaptive radiation, Genetics, Vicariance, Animals, long distance dispersal, Clade, Molecular Biology, Ecology, Evolution, Behavior and Systematics, Phylogeny, 030304 developmental biology, grasslands expansion, 0303 health sciences, historical biogeography, Geography, Ecology, Bayes Theorem, Sequence Analysis, DNA, 15. Life on land, Taxon, Biological dispersal, DEC analyses, Animal Distribution
Abstract

International audience; Thanks to the recent development of integrative approaches that combine dated phylogenies with models of biogeographic evolution, it is becoming more feasible to assess the roles of dispersal and vicariance in creating complex patterns of geographical distribution. However, the historical biogeography of taxa with good dispersal abilities, like birds or flying insects, still remains largely unknown because of the lack of complete phylogenies accompanied by robust estimates of divergence times. In this study, we investigate the evolution and historical biogeography of the globally distributed pest genus Spodoptera (Lepidoptera: Noctuidae) using complete taxon sampling and an extensive set of analyses. Through the analysis of a combined morphological and molecular dataset, we provide the first robust phylogenetic framework for this widespread and economically important group of moths. Historical biogeography approaches indicate that dispersal events have been the driving force in the biogeographic history of the group. One of the most interesting findings of this study is the probable occurrence of two symmetric long-distance dispersal events between the Afrotropical and the Neotropical region, which appear to have occurred in the late Miocene. Even more remarkably, our dated phylogenies reveal that the diversification of the clade that includes specialist grass feeders has followed closely the expansion of grasslands in the Miocene, similar to the adaptive radiation of specialist grazing mammals during the same period.

Published
2012
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12. Comparative analysis of P2-type remnant prophage loci in Xenorhabdus bovienii and Xenorhabdus nematophila required for xenorhabdicin production

Author

Nydia Morales-Soto, Jean-Claude Ogier, Sophie Gaudriault, Steven Forst, Kishore Reddy Venkata Thappeta, University of Wisconsin-Madison, University of Notre Dame, Partenaires INRAE, Diversité, Génomes et Interactions Microorganismes-Insectes, and Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2)

Subjects
DNA, Bacterial, Mitomycin, Prophages, Molecular Sequence Data, Lysin, Repressor, Xenorhabdus, Locus (genetics), Microbiology, Genome, Host Specificity, bacteriocins, 03 medical and health sciences, Viral Proteins, Species Specificity, Lysogenic cycle, Endopeptidases, Genetics, Amino Acid Sequence, Bacteriophage P2, Molecular Biology, Gene, [SDV.BDD]Life Sciences [q-bio]/Development Biology, Prophage, Conserved Sequence, 030304 developmental biology, Recombination, Genetic, 0303 health sciences, biology, 030306 microbiology, Computational Biology, Gene Expression Regulation, Bacterial, Viral Tail Proteins, biology.organism_classification, P2 prophage, Anti-Bacterial Agents, Repressor Proteins, Rec A Recombinases, Genetic Loci, xenorhabdicins, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Photorhabdus, Genome, Bacterial
Abstract

International audience; The xnp1 remnant P2-type prophage of Xenorhabdus nematophila produces xenorhabdicin that is active against closely related species. Xenorhabdicin had not been characterized previously in other Xenorhabdus species. Here, we show xenorhabdicin production in six different strains of Xenorhabdus bovienii. The sequenced genome of X. bovienii SS-2004 was found to possess a highly conserved remnant P2-type cluster (xbp1). Inactivation of the xbpS1 sheath gene resulted in loss of bacteriocin activity, indicating that the xbp1 locus was required for xenorhabdicin production. xbp1 and xnp1 contain a CI-type repressor, a dinI gene involved in stabilization of ssDNA-RecA complexes and are inducible with mitomycin C, suggesting that both loci are regulated by cleavage of the CI repressor. Both xnp1 and xbp1 lack typical P2-type lysis genes but contain a predicted endolysin gene (enp) that may be involved in cell lysis. The main tail fibers of xnp1 and xbp1 are mosaic structures with divergent C-terminal regions suggesting they differ in host specificity. Several genes encoding C-terminal tail fiber fragments are present in the same position in xnp1 and xbp1. Recombination between the main fiber genes and the C-terminal fragments could potentially expand the host range specificity of xenorhabdicin in the respective strains.

Published
2012
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13. Yersinia enterocolitica YopT and Clostridium difficile toxin B induce expression of GILZ in epithelial cells

Author

Bernhard Lüscher, Marie Liesse Asselin-Labat, Martin Köberle, Simon Langer, Erwin Bohn, Robert Zumbihl, David Göppel, Ingo B. Autenrieth, Tanja Grandl, Peer Gaentzsch, Steffen Müller, Susanne Berchtold, Birgit Manncke, Holger Barth, Marc Pallardy, Isabel Sorg, Eberhard Karls Universität Tübingen = Eberhard Karls University of Tuebingen, RWTH Aachen University, Université Paris-Sud - Paris 11 (UP11), The Walter and Eliza Hall Institute of Medical Research (WEHI), Biozentrum [Basel, Suisse], University of Basel (Unibas), Universität Ulm - Ulm University [Ulm, Allemagne], Diversité, Génomes et Interactions Microorganismes-Insectes, Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2), Université Montpellier 2 - Sciences et Techniques (UM2), and Deutsche Forschungsgemeinschaft

Subjects
rho GTP-Binding Proteins, Bacterial Diseases, RHOA, Transcription, Genetic, RHOB, [SDV]Life Sciences [q-bio], NF-KAPPA-B, Gene Expression, lcsh:Medicine, Apoptosis, GTPase, Toxicology, E-Box Elements, Molecular cell biology, PROTECTS T-LYMPHOCYTES, Gene expression, Promoter Regions, Genetic, lcsh:Science, 0303 health sciences, GENE-PRODUCT RHOB, Multidisciplinary, Protein translation, biology, Mechanisms of Signal Transduction, BINDING PROTEINS, NF-kappa B, 3. Good health, Cysteine Endopeptidases, Infectious Diseases, VIRULENCE PLASMID, Medicine, INDUCED LEUCINE-ZIPPER, SIGNALING PATHWAY, Inflammation Mediators, Mitogen-Activated Protein Kinases, Signal transduction, Signal Transduction, Research Article, Transcriptional Activation, Clostridium Difficile, Bacterial Toxins, DNA transcription, Toxic Agents, Clostridium difficile toxin B, THYMOCYTE APOPTOSIS, Microbiology, Yersiniosis, DENDRITIC CELLS, 03 medical and health sciences, Bacterial Proteins, Downregulation and upregulation, Virology, Humans, Biology, Transcription factor, 030304 developmental biology, Inflammation, Base Sequence, 030306 microbiology, Gene Expression Profiling, lcsh:R, Epithelial Cells, INVASIN PROTEIN, Molecular biology, Virulence Factors and Mechanisms, biology.protein, Upstream Stimulatory Factors, lcsh:Q, HeLa Cells, Transcription Factors
Abstract

International audience; Glucocorticoid induced-leucine zipper (GILZ) has been shown to be induced in cells by different stimuli such as glucocorticoids, IL-10 or deprivation of IL-2. GILZ has anti-inflammatory properties and may be involved in signalling modulating apoptosis. Herein we demonstrate that wildtype Yersinia enterocolitica which carry the pYV plasmid upregulated GILZ mRNA levels and protein expression in epithelial cells. Infection of HeLa cells with different Yersinia mutant strains revealed that the protease activity of YopT, which cleaves the membrane-bound form of Rho GTPases was sufficient to induce GILZ expression. Similarly, Clostridium difficile toxin B, another bacterial inhibitor of Rho GTPases induced GILZ expression. YopT and toxin B both increased transcriptional activity of the GILZ promoter in HeLa cells. GILZ expression could not be linked to the inactivation of an individual Rho GTPase by these toxins. However, forced expression of RhoA and RhoB decreased basal GILZ promoter activity. Furthermore, MAPK activation proved necessary for profound GILZ induction by toxin B. Promoter studies and gel shift analyses defined binding of upstream stimulatory factor (USF) 1 and 2 to a canonical c-Myc binding site (E-box) in the GILZ promoter as a crucial step of its trans-activation. In addition we could show that USF-1 and USF-2 are essential for basal as well as toxin B induced GILZ expression. These findings define a novel way of GILZ promoter trans-activation mediated by bacterial toxins and differentiate it from those mediated by dexamethasone or deprivation of IL-2.

Published
2012
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14. Nemaucin, a new antifungal compound, produced the entomopathogenic Xenorhabdus cabanillasii

Author

Givaudan, Alain, Gualtieri, Maxime, Villain-Guillot, Philippe, Pages, Sylvie, Diversité, Génomes et Interactions Microorganismes-Insectes, Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2), and Nosopharm

Subjects
Biodiversity and Ecology, [SDV.SA]Life Sciences [q-bio]/Agricultural sciences, Biodiversité et Ecologie, xenorhabdus, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, génomique des populations, symbiose, Sciences agricoles, Agricultural sciences, biodiversité
Published
2012

15. Cecropins as a marker of Spodoptera frugiperda immunosuppression during entomopathogenic bacterial challenge

Author

Jean-Michel Escoubas, Alain Givaudan, Z. Abi Khattar, Sylvie Pages, Bernard Duvic, N.-A. Volkoff, Véronique Jouan, Delphine Destoumieux-Garzón, N. Essa, Pierre-Alain Girard, Diversité, Génomes et Interactions Microorganismes-Insectes, Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2), Diversité, Génomes & Interactions Microorganismes - Insectes [Montpellier] (DGIMI), Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM), Université Montpellier 2 - Sciences et Techniques (UM2), Ecologie des systèmes marins côtiers (Ecosym), Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS), Université Montpellier 1 (UM1), French Institut National de la Recherche Agronomique, and Centre National de la Recherche Scientifique

Subjects
0106 biological sciences, Physiology, [SDV]Life Sciences [q-bio], Xenorhabdus, medicine.disease_cause, 01 natural sciences, Hemolymph, INFECTION, Invertebrate, Phylogeny, Xenorhabdus mauleonii, Innate immunity, 0303 health sciences, biology, Cecropins, MANDUCA-SEXTA, Antimicrobial, FAMILY, DROSOPHILA, SILKWORM BOMBYX-MORI, ANTIBACTERIAL PEPTIDES, Lepidopteran, EXPRESSION, Molecular Sequence Data, Microbial Sensitivity Tests, Spodoptera, Microbiology, 03 medical and health sciences, medicine, Animals, Amino Acid Sequence, 030304 developmental biology, Molecular mass, Base Sequence, XENORHABDUS-NEMATOPHILA, fungi, Sequence Analysis, DNA, biology.organism_classification, ANTIMICROBIAL PEPTIDES, 010602 entomology, Humoral immunity, Cecropin, Insect Science, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization, INSECT IMMUNITY, Sequence Alignment, Bacteria, Immunosuppression
Abstract

International audience; An antimicrobial peptide (AMP) of the cecropin family was isolated by HPLC from plasma of the insect pest, Spodoptera frugiperda. Its molecular mass is 3910.9 Da as determined by mass spectrometry. Thanks to the EST database Spodobase, we were able to describe 13 cDNAs encoding six different cecropins which belong to the sub-families CecA, CecB, CecC and CecD. The purified peptide identified as CecB1 was chemically synthesized (syCecB1). It was shown to be active against Gram-positive and Gram-negative bacteria as well as fungi. Two closely related entomopathogenic bacteria, Xenorhabdus nematophila F1 and Xenorhabdus mauleonii VC01(T) showed different susceptibility to syCecB1. Indeed, X. nematophila was sensitive to syCecB1 whereas X. mauleonii had a minimal inhibitory concentration (MIC) eight times higher. Interestingly, injection of live X. nematophila into insects did not induce the expression of AMPs in hemolymph. This effect was not observed when this bacterium was heat-killed before injection. On the opposite, both live and heat-killed X. mauleonii induced the expression of AMPs in the hemolymph of S. frugiperda. The same phenomenon was observed for another immune-related protein lacking antimicrobial activity. Altogether, our data suggest that Xenorhabdus strains have developed different strategies to supplant the humoral defense mechanisms of S. frugiperda, either by increasing their resistance to AMPs or by preventing their expression during such host-pathogen interaction. (C) 2012 Elsevier Ltd. All rights reserved.

Published
2011
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16. New insights from comparative genomics of two entomopathogenic bacteria, Photorhabdus and Xenorhabdus

Author

Ogier, Jean-Claude, Gaudriault, Sophie, Diversité, Génomes et Interactions Microorganismes-Insectes, and Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2)

Subjects
[SDV.SA]Life Sciences [q-bio]/Agricultural sciences, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, ComputingMilieux_MISCELLANEOUS
Abstract

National audience

Published
2011

17. Study of expression heterogeneity of flagellar genes in an insect pathogenic bacterium Xenorhabdus using single cell technologies

Author

Lanois, Anne, Jubelin, Grégory, Pages, Sylvie, Givaudan, Alain, Diversité, Génomes et Interactions Microorganismes-Insectes, Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2), Unité de Microbiologie (MIC), and Institut National de la Recherche Agronomique (INRA)

Subjects
Biodiversity and Ecology, Biodiversité et Ecologie, xenorhabdus nematophilus, spodoptera, lutte biologique, fluorescence, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, expression du génome, ComputingMilieux_MISCELLANEOUS, biodiversité
Abstract

National audience

Published
2011

18. Virus-like particles in parasitoids' venom: viral or cellular origin?

Author

Goguet-Surmenian, Emilie, Belghazi, Maya, Ravallec, Marc, Rebuf, Christian, Colinet, Dominique, Poirie, Marylene, Gatti, Jean-Luc, Interactions Biotiques et Santé Végétale, Institut National de la Recherche Agronomique (INRA), Université de la Méditerranée - Aix-Marseille 2, Diversité, Génomes et Interactions Microorganismes-Insectes, and Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2)

Subjects
BIOCHIMIE, [SDV]Life Sciences [q-bio], VIRUS PARTICLE LIKE, PARASITOID, IMMUNITY, TOXICITY, DROSOPHILA, VENOSOME, LEPTOPILINA BOULARDI, DIPTERA, BIOCHEMISTRY, PARASITISM, ComputingMilieux_MISCELLANEOUS, RELATION HOTE-PARASITE
Abstract

National audience

Published
2011

19. Units of plasticity in bacterial genomes: new insight from the comparative genomics of two bacteria interacting with invertebrates, Photorhabdus and Xenorhabdus

Author

Patrick Tailliez, Robert Zumbihl, Alain Givaudan, Alexandra Calteau, Sophie Gaudriault, Jean-Claude Ogier, Steve Forst, Heidi Goodrich-Blair, Garret Suen, David Roche, Claudine Médigue, Zoé Rouy, Diversité, Génomes et Interactions Microorganismes-Insectes, Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Department of Biological Sciences, The Open University [Milton Keynes] (OU), Department of Bacteriology, Veterinary Laboratories Agency, University of Wisconsin-Madison, and Ecologie microbienne des insectes et interactions hôte-pathogène (EMIP)

Subjects
[SDV.SA]Life Sciences [q-bio]/Agricultural sciences, Time Factors, Biodiversité et Ecologie, GENOMIQUE, INSECTE, RGPs, RGPFinder, xenorhabdus, Xenorhabdus, Genome, RNA, Ribosomal, 16S, Genomic island, invertébré, Phylogeny, ComputingMilieux_MISCELLANEOUS, Sequence Deletion, nématode, Gene Rearrangement, bactérie, Genetics, 0303 health sciences, biology, Chromosome Mapping, Genomics, Chromosomes, Bacterial, Host-Pathogen Interactions, Female, bactérie pathogène, Photorhabdus, Research Article, Biotechnology, lcsh:QH426-470, lcsh:Biotechnology, Bacterial genome size, Synteny, Bacterial genetics, Evolution, Molecular, Biodiversity and Ecology, photorhabdus, 03 medical and health sciences, Phylogenetics, lcsh:TP248.13-248.65, Animals, Humans, 030304 developmental biology, Comparative genomics, 030306 microbiology, génome, plasticité, Genetic Variation, biology.organism_classification, Invertebrates, lcsh:Genetics, Genes, Bacterial, Genetic Loci, Evolutionary biology, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Genome, Bacterial
Abstract

Background Flexible genomes facilitate bacterial evolution and are classically organized into polymorphic strain-specific segments called regions of genomic plasticity (RGPs). Using a new web tool, RGPFinder, we investigated plasticity units in bacterial genomes, by exhaustive description of the RGPs in two Photorhabdus and two Xenorhabdus strains, belonging to the Enterobacteriaceae and interacting with invertebrates (insects and nematodes). Results RGPs account for about 60% of the genome in each of the four genomes studied. We classified RGPs into genomic islands (GIs), prophages and two new classes of RGP without the features of classical mobile genetic elements (MGEs) but harboring genes encoding enzymes catalyzing DNA recombination (RGPmob), or with no remarkable feature (RGPnone). These new classes accounted for most of the RGPs and are probably hypervariable regions, ancient MGEs with degraded mobilization machinery or non canonical MGEs for which the mobility mechanism has yet to be described. We provide evidence that not only the GIs and the prophages, but also RGPmob and RGPnone, have a mosaic structure consisting of modules. A module is a block of genes, 0.5 to 60 kb in length, displaying a conserved genomic organization among the different Enterobacteriaceae. Modules are functional units involved in host/environment interactions (22-31%), metabolism (22-27%), intracellular or intercellular DNA mobility (13-30%), drug resistance (4-5%) and antibiotic synthesis (3-6%). Finally, in silico comparisons and PCR multiplex analysis indicated that these modules served as plasticity units within the bacterial genome during genome speciation and as deletion units in clonal variants of Photorhabdus. Conclusions This led us to consider the modules, rather than the entire RGP, as the true unit of plasticity in bacterial genomes, during both short-term and long-term genome evolution.

Published
2011
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20. Characterization of a CENP-B homolog in the holocentric Lepidoptera Spodoptera frugiperda

Author

Benjamin Alassoeur, Philippe Fournier, Slavica Stanojcic, Sylvie Juliant, Alexandre Léger, Emmanuelle d'Alençon, Adly M. M. Abd-Alla, Sylvie Gimenez, Nicolas Nègre, Diversité, Génomes et Interactions Microorganismes-Insectes, Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2), Institut de génétique humaine (IGH), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Department of Pests and Plant Protection, National Research Center, Baculovirus et Thérapie, Centre National de la Recherche Scientifique (CNRS), INRA, and Agence Nationale de la Recherche 07-BLAN-0057-01

Subjects
Transposable element, Male, Chromatin Immunoprecipitation, Retroelements, Centromere, Genome, Insect, Molecular Sequence Data, Down-Regulation, Transposases, Retrotransposon, transposon domestication, macromolecular substances, Biology, Spodoptera, 03 medical and health sciences, 0302 clinical medicine, Genetics, Melanogaster, Animals, Amino Acid Sequence, RNA, Messenger, Cloning, Molecular, RNA, Small Interfering, Codon, Gene, Transposase, 030304 developmental biology, 0303 health sciences, [SDV.GEN]Life Sciences [q-bio]/Genetics, Base Sequence, Reverse Transcriptase Polymerase Chain Reaction, fungi, General Medicine, Sequence Analysis, DNA, transposable element, biology.organism_classification, holocentric, DNA-Binding Proteins, INSECTE, Holocentric, Insect Proteins, Female, Centromere Protein B, 030217 neurology & neurosurgery, CENP-B, Plasmids
Abstract

Correspondance auteur: alencon@supagro.inra.fr; International audience; The discovery of an homolog of the human centromeric protein B, CENP-B, in an EST database of the holocentric insect species Spodoptera frugiperda prompted us to further characterize that gene because i) CENP-B has not been described in invertebrates yet ii) it should be a milestone in the molecular characterization of the holocentric centromere of Lepidoptera. Like its human counterpart, the Sj CENP-B protein is related to the transposase of the pogo transposable element (TE) of D. melanogaster. In this paper, we show evidences that the lepidopteran cenpB gene has evolved from domestication of a transposase. Furthermore, the Sj CENP-B nuclear location and its ability to bind to a retrotransposon derived sequence in vivo argue in favor of a functional homology to CENP-B proteins

Published
2011
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21. Nucleic acids and gene silencing for insecticide strategies

Author

D'Alençon, Emmanuelle, Diversité, Génomes et Interactions Microorganismes-Insectes, and Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2)

Subjects
field of the invention, stratégie, [SDV]Life Sciences [q-bio], economic agricultural, agro-ecology, ecosystems, EP11000132, insecte
Abstract

Etendue géographique : Allemagne

Published
2011

22. Lepidopteran transcriptome analysis following infection by phylogenetically unrelated polydnaviruses highlights differential and common responses

Author

Anne-Nathalie Volkoff, François Cousserans, Pierre Delobel, Véronique Jouan, Philippe Fournier, Eric Wajnberg, Bertille Provost, Pauline Bernardo, Isabelle Darboux, Marc Ravallec, Michael R. Strand, Frédérique Hilliou, Diversité, Génomes et Interactions Microorganismes-Insectes, Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2), Interactions Biotiques et Santé Végétale, Institut National de la Recherche Agronomique (INRA), Sciences Pour l'Oenologie (SPO), Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Université Montpellier 1 (UM1)-Université de Montpellier (UM)-Institut National de la Recherche Agronomique (INRA), Biologie et Génétique des interactions Plantes-parasites pour la Protection Intégrée, Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), and University of Georgia [USA]

Subjects
food.ingredient, Hemocytes, [SDV]Life Sciences [q-bio], Fat Body, Wasps, Gene Expression, Genome, Viral, Spodoptera, Biochemistry, Genome, Transcriptome, 03 medical and health sciences, Viral Proteins, 0302 clinical medicine, food, [SDV.IDA]Life Sciences [q-bio]/Food engineering, Animals, [SPI.GPROC]Engineering Sciences [physics]/Chemical and Process Engineering, RNA, Messenger, polydnavirus, transcriptome, microarray, spodoptera frugiperda, host-parasitoid interaction, polydnavirus host targets, Symbiosis, Molecular Biology, Gene, 030304 developmental biology, Oligonucleotide Array Sequence Analysis, Genetics, 0303 health sciences, biology, Reverse Transcriptase Polymerase Chain Reaction, Polydnavirus, Gene Expression Profiling, biology.organism_classification, Virology, 3. Good health, Gene expression profiling, Polydnaviridae, Insect Science, Insect Proteins, Ichnovirus, Collagen, Bracovirus, Braconidae, 030217 neurology & neurosurgery
Abstract

International audience; The Polydnaviridae is a family of double-stranded DNA viruses that are symbionts of parasitoid wasps. The family is currently divided into two genera, the Ichnovirus (IV) and Bracovirus (BV), which are associated with wasps in the families Ichneumonidae and Braconidae, respectively. IVs and BVs have similar immunosuppressive and developmental effects on parasitized hosts but their encapsidated genomes largely encode different genes. To assess whether IV and BV infection has similar or disparate effects on the transcriptome of shared hosts, we characterized the effects of Hyposoter didymator Ichnovirus (HdIV) and Microplitis demolitor Bracovirus (MdBV) on the fat body and hemocyte transcriptome of Spodoptera frugiperda (Lepidoptera: Noctuidae). Our results indicated that HdIV and MdBV infection alters the abundance of a relatively low proportion of S. frugiperda transcripts at 24 h post-infection. A majority of the transcripts affected by infection also differed between MdBV and HdIV. However, we did identify some host transcripts that were similarly affected by both viruses. A majority of these genes were transcribed in the fat body and most belonged to functional classes with roles in immunity, detoxification, or cell structure. Particularly prominent in this suite of transcripts were genes encoding for predicted motor-related and collagen IV-like proteins. Overall, our data suggest that the broadly similar effects that HdIV and MdBV have on host growth and immunity are not due to these viruses inducing profound changes in host gene expression. Given though that IVs and BVs encode few shared genes, the host transcripts that are similarly affected by HdIV and MdBV could indicate convergence by each virus to target a few processes at the level of transcription that are important for successful parasitism of hosts by H. didymator and M. demolitor.

Published
2011
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23. Studies of the dynamic expression of the Xenorhabdus FliAZ regulon reveal atypical iron-dependent regulation of the flagellin and haemolysin genes during insect infection

Author

Jubelin, Grégory, Pages, Sylvie, Lanois, Anne, Boyer, Marie-Hélène, Gaudriault, Sophie, Ferdy, Jean-Baptiste, Givaudan, Alain, Unité de Microbiologie (MIC), Institut National de la Recherche Agronomique (INRA), Diversité, Génomes et Interactions Microorganismes-Insectes, Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, and INRA [2009_1133_01]

Subjects
Insecta, Virulence, Iron, Biodiversité et Ecologie, xenorhabdus, fungi, Biologie du développement, Sigma Factor, Gene Expression Regulation, Bacterial, Regulon, Development Biology, infection, Biodiversity and Ecology, Hemolysin Proteins, Bacterial Proteins, protéine, Larva, Operon, Animals, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Promoter Regions, Genetic, symbiose, [SDV.BDD]Life Sciences [q-bio]/Development Biology, Flagellin, Plasmids
Abstract

International audience; Xenorhabdus nematophila engages in complex interactions with invertebrates, through its symbiosis with soil nematodes and its pathogenicity to a broad range of insect larvae. Among the regulatory proteins of Xenorhabdus involved in host interactions, the sigma factor FliA and the regulator FliZ, expressed from the fliAZ operon, play a key role in mediating the production of exoenzymes, motility and full virulence in insects (Lanois et al., 2008). In this study, we investigated the dynamics of the FliA-dependent flagellin gene fliC and FliZ-dependent haemolysin genes xaxAB during insect infection and nematode association by carrying out real-time expression analysis using an unstable GFP monitoring system. We showed that expression of the FliAZ-dependent genes in infected insects is not restricted to a specific tissue but increases significantly just prior to host death and reaches a maximal level in larvae cadaver. Using an iron availability reporter construct, we also showed that iron starvation conditions inhibit expression of FliAZ-dependent genes in vitro, as well as during the first steps of the infectious process. These findings shed further light on the role of the FliAZ regulon in the Xenorhabdus life cycle and suggest that iron may constitute a signal governing Xenorhabdus adaptation to shifting host environments.

Published
2011
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24. The entomopathogenic bacterial endosymbionts xenorhabdus and photorhabdus: convergent lifestyles from divergent genomes

Author

Barry S. Goldman, Erin E. H. Tran, Darby R. Sugar, Roy D. Welch, Nydia Morales-Soto, Samantha S. Orchard, Brad Barbazuk, Zoé Rouy, Karina Krasomil-Osterfeld, Brad Goodner, Megan Menard, Sarah L. Tucker, Zijin Du, Renyi Liu, Heidi Goodrich-Blair, Nancy K. Leimgruber, Aaron W. Andersen, Sophie Gaudriault, Gregory R. Richards, Claudine Médigue, Holly Snyder, Pradeep Reddy Marri, Helge B. Bode, Stacie Norton, Jennifer J. Knack, Limaris de Léon, Bosong Xiang, Phil Latreille, Cathy Wheeler, Dongjin Park, Garret Suen, Ransome van der Hoeven, Xiaojun Lu, Youngjin Park, Anne Lanois, Ryan Kukor, Jean Claude Ogier, Eric C. Martens, Kevin Drace, Charles E. Cowles, Brian Tjaden, Kathryn Slominski, Alain Givaudan, Steven C. Slater, Alexander O. Brachmann, Brad Slominski, Archna Bhasin, Kelsea A. Jewell, Barbara A. Qurollo, Steven Forst, Kimberly N. Cowles, Nancy M. Miller, Creg Darby, Carolyn M. Lipke, John M. Chaston, Edna Bode, Department of Bacteriology, Veterinary Laboratories Agency, Monsanto Company, Valdosta State University, Goethe-Universität Frankfurt am Main, University of California [San Francisco] (UC San Francisco), University of California (UC), Mercer University, Diversité, Génomes et Interactions Microorganismes-Insectes, Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2), Department of Ecology and Evolutionary Biology [University of Arizona], University of Arizona, Department of Microbiology and Immunology, Rega Institute for Medical Research, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Department of Biological Sciences, The Open University [Milton Keynes] (OU), Wellesley College, University of Wisconsin - Milwaukee, Department of Biology, Syracuse University, Hiram College, Partenaires INRAE, Department of Biology [Gainesville] (UF|Biology), University of Florida [Gainesville] (UF), DOE Office of Science, This work was funded by the United States Department of Agriculture Grant 2004-35600-14181. National Institutes of Health (NIH) National Research Service Award T32 support was provided to JC and CL (AI55397 'Microbes in Health and Disease'), CC and EHT (AI007414 'Cellular and Molecular Parasitology'), and SO, KC and GR (G07215, 'Molecular Biosciences'). JC was also supported by a National Science Foundation (NSF) Graduate Research Fellowship and EM and CC were supported by the University of Wisconsin-Madison Ira L. Baldwin and Louis and Elsa Thomsen Distinguished Predoctoral Fellowships respectively. LdL was funded by the NSF Research Experience for Microbiology Project 0552809. AB was supported by the NIH grant F32 GM072342. Work in the HG-B lab was supported by grants from the NSF (IOS-0950873 and IOS-0920631). The funders listed above had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. This study was also funded by the Monsanto Company whose role, through the employment of ST, ZD, KK-O, PL, NM, SN, BX, B.Goldman, NL and BQ, involved performing the experiments and analyzing the data., University of California [San Francisco] (UCSF), University of California, Department of Ecology and Evolutionary Biology, Goldman, Barry S., and Goodrich-Blair, Heidi

Subjects
Convergent Evolution, multidisciplinary sciences, Insecta, Nematoda, lcsh:Medicine, Xenorhabdus, Genome, Divergent Evolution, RNA, Ribosomal, 16S, Photorhabdus luminescens, Genome Sequencing, lcsh:Science, bactérie entomopathogène, Phylogeny, nématode, bactérie, Genetics, 0303 health sciences, Multidisciplinary, biology, Photorhabdus, entomopathogenic bacteria, insect pathogenesis, genomic divergence, science and technology, Genomics, Chromosomes, Bacterial, Host-Pathogen Interaction, Host-Pathogen Interactions, Research Article, DNA, Bacterial, Molecular Sequence Data, [SDV.BC]Life Sciences [q-bio]/Cellular Biology, Forms of Evolution, Microbiology, Host-Parasite Interactions, Bacterial genetics, 03 medical and health sciences, Enterobacteriaceae, Species Specificity, Phylogenetics, ddc:570, Animals, Symbiosis, Biology, 030304 developmental biology, Comparative genomics, Evolutionary Biology, écologie microbienne, 030306 microbiology, lcsh:R, fungi, Genetic Variation, Bacteriology, Sequence Analysis, DNA, Comparative Genomics, biology.organism_classification, lcsh:Q, Genome, Bacterial, Bacteria
Abstract

International audience; Members of the genus Xenorhabdus are entomopathogenic bacteria that associate with nematodes. The nematode-bacteria pair infects and kills insects, with both partners contributing to insect pathogenesis and the bacteria providing nutrition to the nematode from available insect-derived nutrients. The nematode provides the bacteria with protection from predators, access to nutrients, and a mechanism of dispersal. Members of the bacterial genus Photorhabdus also associate with nematodes to kill insects, and both genera of bacteria provide similar services to their different nematode hosts through unique physiological and metabolic mechanisms. We posited that these differences would be reflected in their respective genomes. To test this, we sequenced to completion the genomes of Xenorhabdus nematophila ATCC 19061 and Xenorhabdus bovienii SS-2004. As expected, both Xenorhabdus genomes encode many anti-insecticidal compounds, commensurate with their entomopathogenic lifestyle. Despite the similarities in lifestyle between Xenorhabdus and Photorhabdus bacteria, a comparative analysis of the Xenorhabdus, Photorhabdus luminescens, and P. asymbiotica genomes suggests genomic divergence. These findings indicate that evolutionary changes shaped by symbiotic interactions can follow different routes to achieve similar end points.

Published
2011
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25. La fluorescence : Solution pour exploiter les résultats d'expression de gènes bactériens dans une larve d'insecte infectée

Author

Pages, Sylvie, Lanois, Anne, Ginibre, Nadege, Diversité, Génomes et Interactions Microorganismes-Insectes, and Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2)

Subjects
GFP - Green Fluorescent Protein, bactéries entomopathogènes, fluorescence, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, larves d’insectes, ComputingMilieux_MISCELLANEOUS, Xenorhabdus
Abstract

National audience

Published
2011

26. Multigenic families in ichnovirus: a tissue and host specificity study through expression analysis of vankyrins from hyposoter didymator ichnovirus

Author

Gabriel Clavijo, Marie-Anne Mannucci, Tristan Dorémus, Anne-Nathalie Volkoff, Isabelle Darboux, Marc Ravallec, Véronique Jouan, Diversité, Génomes et Interactions Microorganismes-Insectes, Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2), This study was supported by the French Agency for National Research (grant number ANR-09-BLAN-0243-02) and G. Clavijo's post-doctoral position was supported by grants from the French National Institute for Agricultural Research (INRA) and University of Montpellier. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript., and Darboux, Isabelle

Subjects
multidisciplinary sciences, ichnovirus, multigenic families, [SDV]Life Sciences [q-bio], Wasps, Genome, Molecular cell biology, Viral classification, Gene expression, Genetics, 0303 health sciences, Multidisciplinary, biology, Polydnavirus, 3. Good health, Organ Specificity, Medicine, polydnavirus, Research Article, Ankyrins, Gene Expression Regulation, Viral, viral ankyrin (vankyrin), food.ingredient, Science, DNA transcription, Insect Viruses, gene, hyposoter didymator ichnovirus, virus, Spodoptera, Microbiology, Host Specificity, Host-Parasite Interactions, Molecular Genetics, 03 medical and health sciences, food, Virology, Gene family, Animals, Gene Regulation, Symbiosis, Gene, Biology, 030304 developmental biology, 030306 microbiology, Gene Expression Profiling, génome, fungi, biology.organism_classification, Gene expression profiling, Polydnaviridae, Ichnovirus, Gene Function, DNA viruses, Zoology, Entomology
Abstract

The viral ankyrin (vankyrin) gene family is represented in all polydnavirus (PDVs) genomes and encodes proteins homologous to I-kappaBs, inhibitors of NF-kappaB transcription factors. The structural similarities led to the hypothesis that vankyrins mimic eukaryotic factors to subvert important physiological pathways in the infected host. Here, we identified nine vankyrin genes in the genome of the Hyposoter didymator Ichnovirus (HdIV). Time-course gene expression experiments indicate that all members are expressed throughout parasitism of Spodoptera frugiperda, as assessed using RNA extracted from whole larvae. To study tissue and/or species specificity transcriptions, the expression of HdIV vankyrin genes were compared between HdIV-injected larvae of S. frugiperda and S. littoralis. The transcriptional profiles were similar in the two species, including the largely predominant expression of Hd27-vank1 in all tissues examined. However, in various insect cell lines, the expression patterns of HdIV vankyrins differed according to species. No clear relationship between vankyrin expression patterns and abundance of vankyrin-bearing genomic segments were found in the lepidopteran cell lines. Moreover, in these cells, the amount of vankyrin-bearing genomic segments differed substantially between cytosol and nuclei of infected cells, implying the existence of an unexpected step regulating the copy number of HdIV segments in cell nuclei. Our in vitro results reveal a host-specific transcriptional profile of vankyrins that may be related to the success of parasitism in different hosts. In Spodoptera hosts, the predominant expression of Hd27-vank1 suggests that this protein might have pleiotropic functions during parasitism of these insect species.

Published
2011
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27. Génomique des bactéries entomopathogènes Photorhabdus et Xenorhabdus, Apport des NGS dans l'étude des interactions durables

Author

Gaudriault, Sophie, Diversité, Génomes et Interactions Microorganismes-Insectes, and Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2)

Subjects
[SDV.SA]Life Sciences [q-bio]/Agricultural sciences, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, ComputingMilieux_MISCELLANEOUS
Abstract

National audience

Published
2010

28. RNA interference in Lepidoptera: an overview of successful and unsuccessful studies and implications for experimental design

Author

Archana S. Gandhe, Joanna Kotwica, Piotr Bebas, Kostas Iatrou, Jadwiga M. Giebultowicz, Magnus Lundmark, Jianghong Li, Choon Wei Wee, Daniela Nowara, Jisheng Liu, Sriramana Kanginakudru, Michael R. Strand, Antónia Monteiro, Nirotpal Mrinal, Bernard Duvic, Masatoshi Iga, L. N. Gatehouse, Alejandra Bravo, Teruyuki Niimi, Shogo Matsumoto, Atsushi Ohnishi, Jennie S. Garbutt, Mario Soberón, Cristina M. Crava, Cornelis J. P. Grimmelikhuijzen, Hanneke Huvenne, Dwayne D. Hegedus, Frank Hauser, Jean Luc Aymeric, Chunju An, Manchikatla Venkat Rajam, G Felfoldi, Guy Smagghe, Robert M. Simpson, Haruhiko Fujiwara, Alexie Papanicolaou, Ruud A. de Maagd, Salvador Herrero, Luc Swevers, Ingrid Faye, Derek Collinge, François Chevalier, Suzanne V. Saenko, Shuichiro Tomita, Ryo Futahashi, Ping Wang, Maria P. Papakonstantinou, David G. Heckel, Merete Albrechtsen, Martina Meyering-Vos, Kavita Bitra, Astrid T. Groot, Steven Hrycaj, Vicencio Oostra, Javaregowda Nagaraju, Lihua Huang, H.S. Gatehouse, Steven Whyard, Changyou Li, Wenqing Zhang, Umut Toprak, Olle Terenius, Katsuhisa Ozaki, Andrea Barthel, Michael R. Kanost, Martin A. Erlandson, Aleksandar Popadic, Isabel Gómez, Richard H. ffrench-Constant, J. Joe Hull, Peter J. Millichap, Karl H.J. Gordon, Ioannis Eleftherianos, Dept Ecol, University of São Paulo (USP), University of Exeter, Commonwealth Scientific and Industrial Research Organisation [Canberra] (CSIRO), University of Bath [Bath], The George Washington University (GW), Universiteit Gent = Ghent University [Belgium] (UGENT), Centre for DNA Fingerprinting and Diagnostics (CDFD), Dept Plant Biol & Biotechnol, University of Copenhagen = Københavns Universitet (KU), Kansas State University, Diversité, Génomes et Interactions Microorganismes-Insectes, Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2), Dept Entomol., University of Wisconsin-Madison, University of Warsaw (UW), Universidad Nacional Autónoma de México (UNAM), Université Montpellier 2 - Sciences et Techniques (UM2), Res Sch Biol, Australian National University (ANU), Universitat de València (UV), Wageningen University and Research Centre (WUR), Agriculture and Agri-Food [Ottawa] (AAFC), University of Saskatchewan, Stockholm University, Eötvös Loránd University (ELTE), The University of Tokyo (UTokyo), Tokyo Metropolitan University, Partenaires INRAE, National Institute of Advanced Industrial Science and Technology (AIST), Plant & Food Research, Oregon State University (OSU), and Evolutionary Biology (IBED, FNWI)

Subjects
0106 biological sciences, Physiology, [SDV]Life Sciences [q-bio], Tissue uptake, Bioinformatics, 01 natural sciences, RNA interference, Databases, Genetic, Delivery methods, Caenorhabditis elegans, Regulation of gene expression, 0303 health sciences, IMMUNE-RESPONSES, MANDUCA-SEXTA, Lepidoptera, RNA silencing, SILKWORM BOMBYX-MORI, Research Design, Insect Proteins, RNA Interference, MESSENGER-RNA, HELICOVERPA-ARMIGERA, DOUBLE-STRANDED-RNA, Computational biology, Biology, Lepidoptera genitalia, dsRNA properties, 03 medical and health sciences, BACILLUS-THURINGIENSIS, SMALL SILENCING RNAS, Gene silencing, Animals, Gene Silencing, Gene, 030304 developmental biology, RNA, Double-Stranded, Mechanism (biology), fungi, Biology and Life Sciences, ARMYWORM SPODOPTERA-FRUGIPERDA, biology.organism_classification, Immunity, Innate, 010602 entomology, Gene Expression Regulation, Insect Science, Epidermis, CAENORHABDITIS-ELEGANS, Gene function
Abstract

International audience; Gene silencing through RNA interference (RNAi) has revolutionized the study of gene function, particularly in non-model insects. However, in Lepidoptera (moths and butterflies) RNAi has many times proven to be difficult to achieve. Most of the negative results have been anecdotal and the positive experiments have not been collected in such a way that they are possible to analyze. In this review, we have collected detailed data from more than 150 experiments including all to date published and many unpublished experiments. Despite a large variation in the data, trends that are found are that RNAi is particularly successful in the family Saturniidae and in genes involved in immunity. On the contrary, gene expression in epidermal tissues seems to be most difficult to silence. In addition, gene silencing by feeding dsRNA requires high concentrations for success. Possible causes for the variability of success in RNAi experiments in Lepidoptera are discussed. The review also points to a need to further investigate the mechanism of RNAi in lepidopteran insects and its possible connection to the innate immune response. Our general understanding of RNAi in Lepidoptera will be further aided in the future as our public database at http://insectacentral.org/RNAi will continue to gather information on RNAi experiments. (C) 2010 Elsevier Ltd. All rights reserved.

Published
2010
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29. Unités de plasticité dans le génome de Photorhabdus : des réarrangements chromosomiques à l’échelle du temps du laboratoire à l’évolution des espèces

Author

Ogier, Jean-Claude, Calteau, Alexandra, Lanois, Anne, Pages, Sylvie, Roche, David, Rouy, Zoé, Teyssier, Corinne, Tailliez, Patrick, Medigue, Claudine, Jumas-Bilak, Estelle, Givaudan, Alain, Gaudriault, Sophie, Diversité, Génomes et Interactions Microorganismes-Insectes, Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2), Département Microbiologie et Chaîne Alimentaire (MICA), Institut National de la Recherche Agronomique (INRA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Université Montpellier 1 (UM1), and Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDV.SA]Life Sciences [q-bio]/Agricultural sciences, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, ComputingMilieux_MISCELLANEOUS
Abstract

National audience

Published
2010

30. Evaluation de la virulence de bactéries entomopathogènes. Mise en place au laboratoire d'un bio-essai reproductible en conditions contrôlées

Author

Pages, Sylvie, Ginibre, Nadege, Diversité, Génomes et Interactions Microorganismes-Insectes, and Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2)

Subjects
Insectes, larve d'insecte, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Photorhabdus, bactérie entomopathogène, ComputingMilieux_MISCELLANEOUS, Xenorhabdus, courbes de survie, logiciel SPSS
Abstract

National audience

Published
2006

31. Isolation of a new hemimethylated DNA binding protein which regulates dnaA gene expression

Author

Claire C. Bristow, Masamichi Kohiyama, Emmanuelle d'Alençon, Renée Kern, Aziz Taghbalout, Revital Aflalo, Diversité, Génomes et Interactions Microorganismes-Insectes, Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2), Institut Jacques Monod (IJM (UMR_7592)), Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), and D'Alençon, Emmanuelle

Subjects
DNA Replication, Biodiversité et Ecologie, Molecular Sequence Data, Down-Regulation, Biology, Microbiology, DNA-binding protein, Biodiversity and Ecology, 03 medical and health sciences, chemistry.chemical_compound, SeqA protein domain, Bacterial Proteins, Gene expression, Gene Regulation, Amino Acid Sequence, microbiologie, Molecular Biology, Gene, 030304 developmental biology, Regulation of gene expression, 0303 health sciences, Base Sequence, 030306 microbiology, DNA replication, adn, DNA Methylation, Molecular biology, DnaA, DNA-Binding Proteins, chemistry, Gene Expression Regulation, Genes, Bacterial, DNA Transposable Elements, bacteria, escherichia coli, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, DNA
Abstract

In this report, we show that yccV , a gene of unknown function, encodes a protein having an affinity for a hemimethylated oriC DNA and that the protein negatively controls dnaA gene expression in vivo.

Published
2003
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32. flhDC, the flagellar master operon of Xenorhabdus nematophilus: requirement for motility, lipolysis, extracellular hemolysis, and full virulence in insects

Author

Anne Lanois, Alain Givaudan, Diversité, Génomes et Interactions Microorganismes-Insectes, and Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2)

Subjects
Operon, méthode southern blot, Lipolysis, Biodiversité et Ecologie, xenorhabdus, Molecular Sequence Data, Motility, Virulence, Genetics and Molecular Biology, Xenorhabdus, Spodoptera, Biology, Flagellum, Hemolysis, Microbiology, Biodiversity and Ecology, 03 medical and health sciences, Bacterial Proteins, complémentation, pathogène, Animals, Cloning, Molecular, Molecular Biology, 030304 developmental biology, nématode, Phase variation, technique moléculaire, 0303 health sciences, 030306 microbiology, Escherichia coli Proteins, Gene Expression Regulation, Bacterial, Sequence Analysis, DNA, biology.organism_classification, DNA-Binding Proteins, Phenotype, Regulon, Flagella, Mutation, Trans-Activators, biology.protein, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Flagellin
Abstract

Xenorhabdus is a major insect pathogen symbiotically associated with nematodes of the family Steinernematidae. This motile bacterium displays swarming behavior on suitable media, but a spontaneous loss of motility is observed as part of a phenomenon designated phase variation which involves the loss of stationary-phase products active as antibiotics and potential virulence factors. To investigate the role of one of the transcriptional activators of flagellar genes, FlhDC, in motility and virulence, the Xenorhabdus nematophilus flhDC locus was identified by functional complementation of an Escherichia coli flhD null mutant and DNA sequencing. Construction of X. nematophilus flhD null mutants confirmed that the flhDC operon controls flagellin expression but also revealed that lipolytic and extracellular hemolysin activity is flhDC dependent. We also showed that the flhD null mutant displayed a slightly attenuated virulence phenotype in Spodoptera littoralis compared to that of the wild-type strain. Thus, these data indicated that motility, lipase, hemolysin, or unknown functions controlled by the flhDC operon are involved in the infectious process in insects. Our investigation expands the view of the flagellar regulon as a checkpoint coupled to a major network involving bacterial physiological aspects as well as motility.

Published
2000
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33. Cooperation of dopachrome conversion factor with phenoloxidase in the eumelanin pathway in haemolumph of Locusta migratoria (Insecta)

Author

Michel Brehélin, Bernard Duvic, Anas Cherqui, Corine Reibel, Biologie Intégrative et Virologie des Insectes [Univ. de Montpellier II] (BIVI), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de la Recherche Agronomique (INRA), Unité mixte de recherche de pathologie comparée, Centre National de la Recherche Scientifique (CNRS)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de la Recherche Agronomique (INRA), Diversité, Génomes et Interactions Microorganismes-Insectes, Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2), and Université de Montpellier (UM)

Subjects
0106 biological sciences, [SDV.SA]Life Sciences [q-bio]/Agricultural sciences, Indoles, Stereochemistry, Decarboxylation, Blotting, Western, Grasshoppers, 01 natural sciences, Biochemistry, Chemical synthesis, Substrate Specificity, 03 medical and health sciences, chemistry.chemical_compound, Hemolymph, Animals, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, Indolequinones, Molecular Biology, Chromatography, High Pressure Liquid, ComputingMilieux_MISCELLANEOUS, 030304 developmental biology, Melanins, chemistry.chemical_classification, 0303 health sciences, biology, Monophenol Monooxygenase, Quinones, Tryptophan, Substrate (chemistry), Prophenoloxidase, biology.organism_classification, Intramolecular Oxidoreductases, 010602 entomology, INSECTE, Enzyme, chemistry, Insect Science, Dopachrome, Tyrosine, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Locust
Abstract

International audience; Dopachrome Conversion Factor (DCF) was found in the plasma of the locust Locusta migratoria. It has an apparent molecular mass of 85,000. Its K(m) was 0.2 mM at 22 degrees C and pH 7 with L-dopachrome as substrate. It had a high substrate specificity for L-dopachrome, methyl-L-dopachrome and L-dopachrome methyl ester but no activity on the corresponding D-isomers or on dopaminechrome. DCF was devoid of any phenoloxidase activity. Under action of DCF, L-dopachrome was converted into dihydroxyindole, which showed that a decarboxylation occured in the course of reaction. Locust DCF was inhibited by indole-3-propionic acid but not by indole-3- or indole-2-carboxylic acid. It was also inhibited by L-tryptophan in a competitive manner. Inhibition and substrate specificity suggest that a carboxyl group, either free or as a methyl ester, is necessary but not sufficient for enzyme recognition. When purified prophenoloxidase was activated and then added to dihydroxyindole either prepared by chemical synthesis or obtained by action of purified DCF on dopachrome, black pigments with a maximum absorption at 540 nm were generated. Therefore in the eumelanin pathway of locust plasma, phenoloxidase can catalyze the reaction that converts the product generated by DCF.

Published
1998
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34. Correlation of LNCR rasiRNAs Expression with Heterochromatin Formation during Development of the Holocentric Insect Spodoptera frugiperda

Author

Emmanuelle Permal, Sylvie Gimenez, Slavica Stanojcic, Emmanuelle d'Alençon, François Cousserans, Philippe Fournier, Hadi Quesneville, D'Alençon, Emmanuelle, Unité de Recherche Génomique Info (URGI), Institut National de la Recherche Agronomique (INRA), Diversité, Génomes et Interactions Microorganismes-Insectes, and Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2)

Subjects
[SDV]Life Sciences [q-bio], lcsh:Medicine, Plant Science, genomic, Histones, 0302 clinical medicine, Heterochromatin, Molecular Cell Biology, Cluster Analysis, RNA, Small Interfering, lcsh:Science, Genetics, Plant Pests, 0303 health sciences, Genome, Multidisciplinary, Gene Expression Regulation, Developmental, Genomics, Chromatin, Drosophila melanogaster, Holocentric, Research Article, Transposable element, RNA-induced silencing complex, Molecular Sequence Data, heterochromatin, holocentric insect, spodoptera frugiperda, Spodoptera, Biology, 03 medical and health sciences, [SDV.BV]Life Sciences [q-bio]/Vegetal Biology, Animals, RNA-Induced Silencing Complex, RasiRNA, 030304 developmental biology, microorganisme, écologie microbienne, Base Sequence, lcsh:R, Computational Biology, RNA, insecta, Sequence Analysis, DNA, Plant Pathology, hétérochromatine, Mutation, DNA Transposable Elements, lcsh:Q, Chromatin immunoprecipitation, 030217 neurology & neurosurgery, Developmental Biology
Abstract

Repeat-associated small interfering RNAs (rasiRNAs) are derived from various genomic repetitive elements and ensure genomic stability by silencing endogenous transposable elements. Here we describe a novel subset of 46 rasiRNAs named LNCR rasiRNAs due to their homology with one long non-coding RNA (LNCR) of Spodoptera frugiperda. LNCR operates as the intermediate of an unclassified transposable element (TE-LNCR). TE-LNCR is a very invasive transposable element, present in high copy numbers in the S. frugiperda genome. LNCR rasiRNAs are single-stranded RNAs without a prominent nucleotide motif, which are organized in two distinct, strand-specific clusters. The expression of LNCR and LNCR rasiRNAs is developmentally regulated. Formation of heterochromatin in the genomic region where three copies of the TE-LNCR are embedded was followed by chromatin immunoprecipitation (ChIP) and we observed this chromatin undergo dynamic changes during development. In summary, increased LNCR expression in certain developmental stages is followed by the appearance of a variety of LNCR rasiRNAs which appears to correlate with subsequent accumulation of a heterochromatic histone mark and silencing of the genomic region with TE-LNCR. These results support the notion that a repeat-associated small interfering RNA pathway is linked to heterochromatin formation and/or maintenance during development to establish repression of the TE-LNCR transposable element. This study provides insights into the rasiRNA silencing pathway and its role in the formation of fluctuating heterochromatin during the development of one holocentric organism.

Published
2011
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35. Purification and partial characterization of a beta-1,3-glucan-binding-protein membrane receptor from blood cells of the crayfish Pacifastacus leniusculus

Author

Bernard Duvic, Kenneth Söderhäll, Diversité, Génomes et Interactions Microorganismes-Insectes, Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2), and Swedish University of Agricultural Sciences (SLU)

Subjects
[SDV.SA]Life Sciences [q-bio]/Agricultural sciences, Protein subunit, Blotting, Western, Receptors, Cell Surface, Astacoidea, Biology, Binding, Competitive, Biochemistry, Chromatography, DEAE-Cellulose, 03 medical and health sciences, Laminarin, chemistry.chemical_compound, 0302 clinical medicine, Cell surface receptor, Lectins, Animals, Electrophoresis, Gel, Two-Dimensional, Binding site, Receptor, 030304 developmental biology, 0303 health sciences, Blood Cells, Molecular mass, Binding protein, Cell Membrane, Molecular Weight, Kinetics, chemistry, 030220 oncology & carcinogenesis, Electrophoresis, Polyacrylamide Gel, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Carrier Proteins, Cation-dependent mannose-6-phosphate receptor
Abstract

International audience; A receptor for the 100 kDa beta-1,3-glucan-binding protein [Duvic, B. and Söderhäll, K. (1990) J. Biol. Chem. 265, 9327-9332] has been purified from hemocyte membranes of the crayfish Pacifastacus leniusculus. The purification was achieved by DEAE-cellulose chromatography of detergent-solubilized membranes. The receptor had an apparent molecular mass of 350 kDa when subjected to native polyacrylamide-gel electrophoresis and was composed of two non-covalently associated subunits of about 230 kDa and 90 kDa, as judged by SDS/polyacrylamide-gel electrophoresis or two-dimensional electrophoresis. The receptor could only bind the beta-1,3-glucan-binding protein if this protein had previously reacted with a beta-1,3-glucan, laminarin, and the binding site was located on the 230 kDa subunit. The binding of laminarin-treated beta-1,3-glucan-binding protein to its receptor was a saturable process and binding data indicated a single high-affinity-binding site with a Kd of 0.35 +/- 0.15 microM as determined by Scatchard analysis. The receptor had a requirement for divalent cations and a pH optimum of 6.5 for binding the laminarin-treated beta-1,3-glucan-binding protein. Laminarin, as well as oligosaccharides such as D-glucose, sialic acid, N-acetyl glucosamine or methyl-alpha-D-mannoside, could not affect the binding of the beta-1,3-glucan-binding protein to its receptor.

Published
1992
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36. The proPO-system and associated proteins; role in cellular communication in arthropods

Author

B. Duvic, Anna Aspán, Kenneth Söderhäll, Swedish University of Agricultural Sciences (SLU), Diversité, Génomes et Interactions Microorganismes-Insectes, and Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2)

Subjects
[SDV.SA]Life Sciences [q-bio]/Agricultural sciences, 0303 health sciences, Enzyme Precursors, Insecta, 030302 biochemistry & molecular biology, Immunology, Computational biology, Cell Communication, Biology, Cellular communication, 03 medical and health sciences, Immunity, Animals, [SDV.BDD]Life Sciences [q-bio]/Development Biology, Arthropods, ComputingMilieux_MISCELLANEOUS, Catechol Oxidase, 030304 developmental biology
Abstract

International audience

Published
1990
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37. Purification and characterization of a beta-1,3-glucan binding protein from plasma of the crayfish Pacifastacus leniusculus

Author

Bernard Duvic, Kenneth Söderhäll, Diversité, Génomes et Interactions Microorganismes-Insectes, Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2), and Swedish University of Agricultural Sciences (SLU)

Subjects
[SDV.SA]Life Sciences [q-bio]/Agricultural sciences, beta-Glucans, Molecular Sequence Data, Astacoidea, Biochemistry, Chromatography, Affinity, 03 medical and health sciences, Laminarin, chemistry.chemical_compound, Affinity chromatography, Polysaccharides, Protein A/G, Animals, Chemical Precipitation, Amino Acid Sequence, Isoelectric Point, Amino Acids, Molecular Biology, Peptide sequence, Glucans, [SDV.BDD]Life Sciences [q-bio]/Development Biology, 030304 developmental biology, Mannan, Gel electrophoresis, Immunoassay, 0303 health sciences, biology, Monophenol Monooxygenase, Binding protein, 04 agricultural and veterinary sciences, Cell Biology, Molecular biology, Molecular Weight, carbohydrates (lipids), Isoelectric point, chemistry, 040102 fisheries, biology.protein, 0401 agriculture, forestry, and fisheries, Electrophoresis, Polyacrylamide Gel, Carrier Proteins, Peptide Hydrolases
Abstract

International audience; The plasma of the crayfish Pacifastacus leniusculus contains a protein which is able to bind to laminarin (a soluble beta-1,3-glucan) and which has been isolated by two independent methods, affinity precipitation with a beta-1,3-glucan or immunoaffinity chromatography. The purified beta-1,3-glucan binding protein was homogenous as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. It is a monomeric glycoprotein with a molecular mass of approximately 100,000 Da and an isoelectric point of approximately 5.0. Amino acid analysis showed a very high similarity with the amino acid composition of beta-1,3-glucan binding proteins recently purified from two insects, the cockroach Blaberus craniifer and the silkworm Bombyx mori. The N-terminal amino acid sequence was determined to be: H2N-Asp-Ala-Gly-X-Ala-Ser-Leu-Val-Thr-Asn-Phe-Asn-Ser-Ala-Lys-Leu-X-X-Ly s--- Using monospecific rabbit polyclonal antibodies, the presence of this protein has also been shown within the blood cells. The purified beta-1,3-glucan binding protein did not show any peptidase or phenoloxidase activity but was able to enhance the activation of hemocyte-derived peptidase and prophenoloxidase only in the presence of the beta-1,3-glucan, laminarin, whereas mannan, dextran (alpha-glucan), or cellulose (beta-1,4-glucan) incubated with the beta-1,3-glucan binding protein had no effect on these enzyme activities. The beta-1,3-glucan binding protein could only be affinity-precipitated from crayfish plasma by the beta-1,3-glucans laminarin or curdlan (an insoluble beta-1,3-glucan), while mannan or dextran did not bind to the beta-1,3-glucan binding protein. No hemagglutinating activity of the purified beta-1,3-glucan binding protein could be detected.

Published
1990

38. Caractérisation de la protéine de transport de la 20-hydroxyecdysone chez un insecte, Locusta migratoria

Author

Duvic, Bernard, Diversité, Génomes et Interactions Microorganismes-Insectes, Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2), Université Louis Pasteur (Strasbourg 1), and Jules A. Hoffmann

Subjects
[SDV.BA.ZI]Life Sciences [q-bio]/Animal biology/Invertebrate Zoology, endocrinologie, ecdystéroïde, these, transporteur
Published
1988

39. Cabanillasin, a novel antibiotic, produced the entomopathogenic Xenorhabdus cabanillasii

Author

Alain Givaudan, Maxime Gualtieri, Philippe Villain-Guillot, Sylvie Pages, Diversité, Génomes et Interactions Microorganismes-Insectes, Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2), and Nosopharm

Subjects
Biodiversity and Ecology, antibiotique, Biodiversité et Ecologie, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, biodiversité

40. A novel and diverse family of filamentous DNA viruses associated with parasitic wasps.

Author

Guinet B, Leobold M, Herniou EA, Bloin P, Burlet N, Bredlau J, Navratil V, Ravallec M, Uzbekov R, Kester K, Gundersen Rindal D, Drezen JM, Varaldi J, and Bézier A

Abstract

Large dsDNA viruses from the Naldaviricetes class are currently composed of four viral families infecting insects and/or crustaceans. Since the 1970s, particles described as filamentous viruses (FVs) have been observed by electronic microscopy in several species of Hymenoptera parasitoids but until recently, no genomic data was available. This study provides the first comparative morphological and genomic analysis of these FVs. We analyzed the genomes of seven FVs, six of which were newly obtained, to gain a better understanding of their evolutionary history. We show that these FVs share all genomic features of the Naldaviricetes while encoding five specific core genes that distinguish them from their closest relatives, the Hytrosaviruses. By mining public databases, we show that FVs preferentially infect Hymenoptera with parasitoid lifestyle and that these viruses have been repeatedly integrated into the genome of many insects, particularly Hymenoptera parasitoids, overall suggesting a long-standing specialization of these viruses to parasitic wasps. Finally, we propose a taxonomical revision of the class Naldaviricetes in which FVs related to the Leptopilina boulardi FV constitute a fifth family. We propose to name this new family, Filamentoviridae., Competing Interests: None declared., (© The Author(s) 2024. Published by Oxford University Press.)

Published
2024
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41. A Behavior-Manipulating Virus Relative as a Source of Adaptive Genes for Drosophila Parasitoids.

Author

Di Giovanni D, Lepetit D, Guinet B, Bennetot B, Boulesteix M, Couté Y, Bouchez O, Ravallec M, and Varaldi J

Subjects
Adaptation, Biological, Animals, Behavior, Animal, Female, Genome, Insect, Larva parasitology, Selection, Genetic, Wasps ultrastructure, Drosophila parasitology, Gene Transfer, Horizontal, Genes, Viral, Wasps genetics, Wasps virology
Abstract

Some species of parasitic wasps have domesticated viral machineries to deliver immunosuppressive factors to their hosts. Up to now, all described cases fall into the Ichneumonoidea superfamily, which only represents around 10% of hymenoptera diversity, raising the question of whether such domestication occurred outside this clade. Furthermore, the biology of the ancestral donor viruses is completely unknown. Since the 1980s, we know that Drosophila parasitoids belonging to the Leptopilina genus, which diverged from the Ichneumonoidea superfamily 225 Ma, do produce immunosuppressive virus-like structure in their reproductive apparatus. However, the viral origin of these structures has been the subject of debate. In this article, we provide genomic and experimental evidence that those structures do derive from an ancestral virus endogenization event. Interestingly, its close relatives induce a behavior manipulation in present-day wasps. Thus, we conclude that virus domestication is more prevalent than previously thought and that behavior manipulation may have been instrumental in the birth of such associations., (© The Author(s) 2020. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Published
2020
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42. Spatiotemporal expression of the putative MdtABC efflux pump of Phtotorhabdus luminescens occurs in a protease-dependent manner during insect infection.

Author

Abi Khattar Z, Lanois A, Hadchity L, Gaudriault S, and Givaudan A

Subjects
Animals, Anti-Bacterial Agents pharmacology, Copper pharmacology, Genes, MDR genetics, Microbial Sensitivity Tests, Mutation, Operon genetics, Phenotype, Photorhabdus drug effects, Promoter Regions, Genetic genetics, Transcription, Genetic drug effects, Bacterial Proteins genetics, Gene Expression Profiling, Locusta migratoria microbiology, Peptide Hydrolases metabolism, Photorhabdus genetics, Photorhabdus physiology
Abstract

Photorhabdus luminescens is an enterobacterium establishing a mutualistic symbiosis with nematodes, that also kills insects after septicaemia and connective tissue colonization. The role of the bacterial mdtABC genes encoding a putative multidrug efflux system from the resistance/nodulation/cell division family was investigated. We showed that a mdtA mutant and the wild type had similar levels of resistance to antibiotics, antimicrobial peptides, metals, detergents and bile salts. The mdtA mutant was also as pathogenic as the wild-type following intrahaemocoel injection in Locusta migratoria, but had a slightly attenuated phenotype in Spodoptera littoralis. A transcriptional fusion of the mdtA promoter (PmdtA) and the green fluorescent protein (gfp) encoding gene was induced by copper in bacteria cultured in vitro. The PmdtA-gfp fusion was strongly induced within bacterial aggregates in the haematopoietic organ during late stages of infection in L. migratoria, whereas it was only weakly expressed in insect plasma throughout infection. A medium supplemented with haematopoietic organ extracts induced the PmdtA-gfp fusion ex vivo, suggesting that site-specific mdtABC expression resulted from insect signals from the haematopoietic organ. Finally, we showed that protease inhibitors abolished ex vivo activity of the PmdtA-gfp fusion in the presence of haematopoietic organ extracts, suggesting that proteolysis by-products play a key role in upregulating the putative MdtABC efflux pump during insect infection with P. luminescens., Competing Interests: The authors have declared that no competing interests exist.

Published
2019
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43. Contrasting Patterns of Genomic Diversity Reveal Accelerated Genetic Drift but Reduced Directional Selection on X-Chromosome in Wild and Domestic Sheep Species.

Author

Chen ZH, Zhang M, Lv FH, Ren X, Li WR, Liu MJ, Nam K, Bruford MW, and Li MH

Subjects
Animals, Animals, Wild, Chromosomes, Mammalian genetics, Female, Genes, X-Linked genetics, Genetics, Population, Genomics, Humans, Male, Molecular Sequence Data, Polymorphism, Single Nucleotide, Pseudoautosomal Regions, Sheep, Domestic genetics, Genetic Drift, Genetic Variation, Selection, Genetic, Sheep genetics, X Chromosome genetics
Abstract

Analyses of genomic diversity along the X chromosome and of its correlation with autosomal diversity can facilitate understanding of evolutionary forces in shaping sex-linked genomic architecture. Strong selective sweeps and accelerated genetic drift on the X-chromosome have been inferred in primates and other model species, but no such insight has yet been gained in domestic animals compared with their wild relatives. Here, we analyzed X-chromosome variability in a large ovine data set, including a BeadChip array for 943 ewes from the world's sheep populations and 110 whole genomes of wild and domestic sheep. Analyzing whole-genome sequences, we observed a substantially reduced X-to-autosome diversity ratio (∼0.6) compared with the value expected under a neutral model (0.75). In particular, one large X-linked segment (43.05-79.25 Mb) was found to show extremely low diversity, most likely due to a high density of coding genes, featuring highly conserved regions. In general, we observed higher nucleotide diversity on the autosomes, but a flat diversity gradient in X-linked segments, as a function of increasing distance from the nearest genes, leading to a decreased X: autosome (X/A) diversity ratio and contrasting to the positive correlation detected in primates and other model animals. Our evidence suggests that accelerated genetic drift but reduced directional selection on X chromosome, as well as sex-biased demographic events, explain low X-chromosome diversity in sheep species. The distinct patterns of X-linked and X/A diversity we observed between Middle Eastern and non-Middle Eastern sheep populations can be explained by multiple migrations, selection, and admixture during the domestic sheep's recent postdomestication demographic expansion, coupled with natural selection for adaptation to new environments. In addition, we identify important novel genes involved in abnormal behavioral phenotypes, metabolism, and immunity, under selection on the sheep X-chromosome.

Published
2018
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44. Flagellar Regulation and Virulence in the Entomopathogenic Bacteria-Xenorhabdus nematophila and Photorhabdus luminescens.

Author

Givaudan A and Lanois A

Subjects
Symbiosis, Virulence, Flagella physiology, Photorhabdus, Xenorhabdus
Abstract

There is a complex interplay between the regulation of flagellar motility and the expression of virulence factors in many bacterial pathogens. Here, we review the literature on the direct and indirect roles of flagellar motility in mediating the tripartite interaction between entomopathogenic bacteria (Photorhabdus and Xenorhabdus), their nematode hosts, and their insect targets. First, we describe the swimming and swarming motility of insect pathogenic bacteria and its impact on insect colonization. Then, we describe the coupling between the expression of flagellar and virulence genes and the dynamic of expression of the flagellar regulon during invertebrate infection. We show that the flagellar type 3 secretion system (T3SS) is also an export apparatus for virulence proteins in X. nematophila. Finally, we demonstrate that phenotypic variation, a common property of the bacterial symbionts of nematodes, also alters flagellar motility in Photorhabdus and Xenorhabdus. Finally, the so-called phenotypic heterogeneity phenomenon in the flagellar gene expression network will be also discussed. As the main molecular studies were performed in X. nematophila, future perspectives for the study of the interplay between flagellum and invertebrate interactions in Photorhabdus will be discussed.

Published
2017
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45. Comparative Genomics between Two Xenorhabdus bovienii Strains Highlights Differential Evolutionary Scenarios within an Entomopathogenic Bacterial Species.

Author

Bisch G, Ogier JC, Médigue C, Rouy Z, Vincent S, Tailliez P, Givaudan A, and Gaudriault S

Subjects
Animals, Nematoda microbiology, Pseudogenes, Virulence genetics, Xenorhabdus pathogenicity, Evolution, Molecular, Genetic Speciation, Genome, Bacterial, Xenorhabdus genetics
Abstract

Bacteria of the genus Xenorhabdus are symbionts of soil entomopathogenic nematodes of the genus Steinernema. This symbiotic association constitutes an insecticidal complex active against a wide range of insect pests. Within Xenorhabdus bovienii species, the X. bovienii CS03 strain (Xb CS03) is nonvirulent when directly injected into lepidopteran insects, and displays a low virulence when associated with its Steinernema symbiont. The genome of Xb CS03 was sequenced and compared with the genome of a virulent strain, X. bovienii SS-2004 (Xb SS-2004). The genome size and content widely differed between the two strains. Indeed, Xb CS03 had a large genome containing several specific loci involved in the inhibition of competitors, including a few NRPS-PKS loci (nonribosomal peptide synthetases and polyketide synthases) producing antimicrobial molecules. Consistently, Xb CS03 had a greater antimicrobial activity than Xb SS-2004. The Xb CS03 strain contained more pseudogenes than Xb SS-2004. Decay of genes involved in the host invasion and exploitation (toxins, invasins, or extracellular enzymes) was particularly important in Xb CS03. This may provide an explanation for the nonvirulence of the strain when injected into an insect host. We suggest that Xb CS03 and Xb SS-2004 followed divergent evolutionary scenarios to cope with their peculiar life cycle. The fitness strategy of Xb CS03 would involve competitor inhibition, whereas Xb SS-2004 would quickly and efficiently kill the insect host. Hence, Xenorhabdus strains would have widely divergent host exploitation strategies, which impact their genome structure., (© The Author 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.)

Published
2016
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46. Involvement of the CasK/R two-component system in optimal unsaturation of the Bacillus cereus fatty acids during low-temperature growth.

Author

Diomandé SE, Nguyen-the C, Abee T, Tempelaars MH, Broussolle V, and Brillard J

Subjects
Bacillus cereus genetics, Cold Temperature, Culture Media chemistry, Fatty Acid Desaturases metabolism, Fatty Acids analysis, Gene Expression Profiling, Guanylate Kinases genetics, Humans, Phospholipids metabolism, Receptors, Calcium-Sensing genetics, Adaptation, Physiological genetics, Bacillus cereus enzymology, Fatty Acids metabolism, Food Microbiology, Foodborne Diseases microbiology, Guanylate Kinases physiology, Receptors, Calcium-Sensing physiology
Abstract

Bacillus cereus sensu lato is composed of a set of ubiquitous strains including human pathogens that can survive a range of food processing conditions, grow in refrigerated food, and sometimes cause food poisoning. We previously identified the two-component system CasK/R that plays a key role in cold adaptation. To better understand the CasK/R-controlled mechanisms that support low-temperature adaptation, we performed a transcriptomic analysis on the ATCC 14579 strain and its isogenic ∆casK/R mutant grown at 12°C. Several genes involved in fatty acid (FA) metabolism were downregulated in the mutant, including desA and desB encoding FA acyl-lipid desaturases that catalyze the formation of a double-bond on the FA chain in positions ∆5 and ∆10, respectively. A lower proportion of FAs presumably unsaturated by DesA was observed in the ΔcasK/R strain compared to the parental strain while no difference was found for FAs presumably unsaturated by DesB. Addition of phospholipids from egg yolk lecithin rich in unsaturated FAs, to growth medium, abolished the cold-growth impairment of ΔcasK/R suggesting that exogenous unsaturated FAs can support membrane-level modifications and thus compensate for the decreased production of these FAs in the B. cereus ∆casK/R mutant during growth at low temperature. Our findings indicate that CasK/R is involved in the regulation of FA metabolism, and is necessary for cold adaptation of B. cereus unless an exogenous source of unsaturated FAs is available., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Published
2015
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47. Macrophage Bactericidal Activities against Staphylococcus aureus Are Enhanced In Vivo by Selenium Supplementation in a Dose-Dependent Manner.

Author

Aribi M, Meziane W, Habi S, Boulatika Y, Marchandin H, and Aymeric JL

Subjects
Animals, Arginase immunology, Cells, Cultured, Dietary Supplements analysis, Macrophages, Peritoneal immunology, Male, Mesocricetus, Nitric Oxide immunology, Phagocytosis drug effects, Staphylococcal Infections immunology, Staphylococcus aureus growth & development, Staphylococcus aureus immunology, Anti-Bacterial Agents pharmacology, Macrophage Activation drug effects, Macrophages, Peritoneal drug effects, Macrophages, Peritoneal microbiology, Selenium pharmacology, Staphylococcal Infections drug therapy, Staphylococcus aureus drug effects
Abstract

Background: Dietary selenium is of fundamental importance to maintain optimal immune function and enhance immunity during infection. To this end, we examined the effect of selenium on macrophage bactericidal activities against Staphylococcus aureus., Methods: Assays were performed in golden Syrian hamsters and peritoneal macrophages cultured with S. aureus and different concentrations of selenium., Results: Infected and selenium-supplemented animals have significantly decreased levels of serum nitric oxide (NO) production when compared with infected but non-selenium-supplemented animals at day 7 post-infection (p < 0.05). A low dose of 5 ng/mL selenium induced a significant decrease in macrophage NO production, but significant increase in hydrogen peroxide (H2O2) levels (respectively, p = 0.009, p < 0.001). The NO production and H2O2 levels were significantly increased with increasing concentrations of selenium; the optimal macrophage activity levels were reached at 20 ng/mL. The concentration of 5 ng/mL of selenium induced a significant decrease in the bacterial arginase activity but a significant increase in the macrophage arginase activity. The dose of 20 ng/mL selenium induced a significant decrease of bacterial growth (p < 0.0001) and a significant increase in macrophage phagocytic activity, NO production/arginase balance and S. aureus killing (for all comparisons, p < 0.001)., Conclusions: Selenium acts in a dose-dependent manner on macrophage activation, phagocytosis and bacterial killing suggesting that inadequate doses may cause a loss of macrophage bactericidal activities and that selenium supplementation could enhance the in vivo control of immune response to S. aureus.

Published
2015
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48. Isolation, characterization, kinetics, and enzymatic and nonenzymatic microbicidal activities of a novel c-type lysozyme from plasma of Schistocerca gregaria (Orthoptera: Acrididae).

Author

Elmogy M, Bassal TT, Yousef HA, Dorrah MA, Mohamed AA, and Duvic B

Subjects
Amino Acid Sequence, Animals, Anti-Infective Agents chemistry, Chitinases analysis, Microbial Sensitivity Tests, Molecular Sequence Data, Monophenol Monooxygenase metabolism, Muramidase chemistry, Muramidase isolation & purification, Anti-Infective Agents isolation & purification, Grasshoppers enzymology, Muramidase metabolism
Abstract

A protein, designated as Sgl, showing a muramidase lytic activity to the cell wall of the Gram-positive bacterium Micrococcus lysodeikticus was isolated for the first time from plasma of Escherichia coli-immunized fifth instar Schistocerca gregaria. The isolated Sgl was detected as a single protein band, on both native- and SDS-PAGE, has a molecular weight of ∼15.7 kDa and an isoelectric point (pI) of ca 9.3 and its antiserum has specifically recognized its isolated form. Fifty-nine percentage of Sgl lytic activity was recovered in the isolated fractions and yielded ca 126-fold increase in specific activity than that of the crude. The partial N-terminal amino acid sequence of the Sgl has 55 and 40% maximum identity with Bombyx mori and Gallus gallus c-type lysozymes, respectively. The antibacterial activity against the Gram-positive and the Gram-negative bacteria were comparatively stronger than that of the hen egg white lysozyme (HEWL). The detected Sgl poration to the inner membrane that reach a maximum ability after 3 h was suggested to operate as a nonenzymatic mechanism for Gram-negative bacterial cell lysis, as tested in a permease-deficient E. coli, ML-35 strain. Sgl showed a maximal muramidase activity at pH 6.2, 30-50°C, and 0.05 M Ca(2+) or Mg(2+); and has a Km of 0.5 μg/ml and a Vmax of 0.518 with M. lysodeikticus as a substrate. The Sgl displayed a chitinase activity against chitin with a Km of 0.93 mg/ml and a Vmax of 1.63., (© The Author 2015. Published by Oxford University Press on behalf of the Entomological Society of America.)

Published
2015
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49. Les densovirus : une « massive attaque » chez les arthropodes.

Author

Gosselin Grenet AS, Salasc F, Francois S, Mutuel D, Dupressoir T, Multeau C, Perrin A, and Ogliastro M

Abstract

Densoviruses (DVs) are parvoviruses of arthropods and causative agents of natural epizootics in insects and crustaceans populations. Structurally simple, these small DNA viruses, display a large diversity of genomic sequences, structures and organizations. Such diversity, together with the diversity of their invertebrate hosts, from shrimps to mosquitoes and recently including sea stars, suggests that DVs are largely unknown and ubiquitous in the environment. Densoviruses are considered as a model of choice to study virus-host interactions and their evolution at different scales, from individuals to populations. This review summarizes the knowledge on densovirus biology obtained through mechanistic and global approaches. Finally, the potential use of these viruses as biological control agents against insect pests and disease-vectors are exposed.

Published
2015
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50. Xenorhabdus bovienii CS03, the bacterial symbiont of the entomopathogenic nematode Steinernema weiseri, is a non-virulent strain against lepidopteran insects.

Author

Bisch G, Pagès S, McMullen JG 2nd, Stock SP, Duvic B, Givaudan A, and Gaudriault S

Subjects
Animals, Host-Pathogen Interactions, Immunity, Humoral, Larva immunology, Larva microbiology, Moths immunology, Symbiosis, Virulence, Xenorhabdus physiology, Moths microbiology, Nematoda microbiology, Xenorhabdus pathogenicity
Abstract

Xenorhabdus bacteria (γ-proteobacteria: Enterobacteriaceae) have dual lifestyles. They have a mutualistic relationship with Steinernema nematodes (Nematoda: Steinernematidae) and are pathogenic to a wide range of insects. Each Steinernema nematode associates with a specific Xenorhabdus species. However, a Xenorhabdus species can have multiple nematode hosts. For example, Xenorhabdus bovienii (Xb) colonizes at least nine Steinernema species from two different phylogenetic clades. The Steinernema-Xb partnership has been found in association with different insect hosts. Biological and molecular data on the Steinernema jollieti-Xb strain SS-2004 pair have recently been described. In particular, the Xb SS-2004 bacteria are virulent alone after direct injection into insect, making this strain a model for studying Xb virulence. In this study, we searched for Xb strains attenuated in virulence. For this purpose, we underwent infection assays with five Steinernema spp.-Xb pairs with two insects, Galleria mellonella (Lepidoptera: Pyralidae) and Spodoptera littoralis (Lepidoptera: Noctuidae). The S. weiseri-Xb CS03 pair showed attenuated virulence and lower fitness in S. littoralis in comparison to the other nematode-bacteria pairs. Furthermore, when injected alone into the hemolymph of G. mellonella or S. littoralis, the Xb CS03 bacterial strain was the only non-virulent strain. By comparison with the virulent Xb SS-2004 strain, Xb CS03 showed an increased sensitivity to the insect antimicrobial peptides, suggesting an attenuated response to the insect humoral immunity. To our current knowledge, Xb CS03 is the first non-virulent Xb strain identified. We propose this strain as a new model for studying the Xenorhabdus virulence., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Published
2015
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