Nehme Nadine T, Quintin Jessica, Cho Ju Hyun, Lee Janice, Lafarge Marie-Céline, Kocks Christine, Ferrandon Dominique
Relative roles of the cellular and humoral responses in the Drosophila host defense against three gram-positive bacterial infections Article de journal
Dans: PLoS ONE, vol. 6, no. 3, p. e14743, 2011, ISSN: 1932-6203.
Résumé | Liens | BibTeX | Étiquettes: Animals, Antimicrobial Cationic Peptides, Carrier Proteins, Cell Surface, Cellular, Enterococcus faecalis, ferrandon, Gram-Positive Bacteria, Gram-Positive Bacterial Infections, Host-Pathogen Interactions, Humoral, Immunity, Innate, M3i, Micrococcus luteus, Opsonin Proteins, Phagocytosis, Receptors, Signal Transduction, Solubility, Staphylococcus aureus
@article{nehme_relative_2011b,
title = {Relative roles of the cellular and humoral responses in the Drosophila host defense against three gram-positive bacterial infections},
author = {Nadine T Nehme and Jessica Quintin and Ju Hyun Cho and Janice Lee and Marie-Céline Lafarge and Christine Kocks and Dominique Ferrandon},
doi = {10.1371/journal.pone.0014743},
issn = {1932-6203},
year = {2011},
date = {2011-01-01},
journal = {PLoS ONE},
volume = {6},
number = {3},
pages = {e14743},
abstract = {BACKGROUND: Two NF-kappaB signaling pathways, Toll and immune deficiency (imd), are required for survival to bacterial infections in Drosophila. In response to septic injury, these pathways mediate rapid transcriptional activation of distinct sets of effector molecules, including antimicrobial peptides, which are important components of a humoral defense response. However, it is less clear to what extent macrophage-like hemocytes contribute to host defense. METHODOLOGY/PRINCIPAL FINDINGS: In order to dissect the relative importance of humoral and cellular defenses after septic injury with three different gram-positive bacteria (Micrococcus luteus, Enterococcus faecalis, Staphylococcus aureus), we used latex bead pre-injection to ablate macrophage function in flies wildtype or mutant for various Toll and imd pathway components. We found that in all three infection models a compromised phagocytic system impaired fly survival--independently of concomitant Toll or imd pathway activation. Our data failed to confirm a role of the PGRP-SA and GNBP1 Pattern Recognition Receptors for phagocytosis of S. aureus. The Drosophila scavenger receptor Eater mediates the phagocytosis by hemocytes or S2 cells of E. faecalis and S. aureus, but not of M. luteus. In the case of M. luteus and E. faecalis, but not S. aureus, decreased survival due to defective phagocytosis could be compensated for by genetically enhancing the humoral immune response. CONCLUSIONS/SIGNIFICANCE: Our results underscore the fundamental importance of both cellular and humoral mechanisms in Drosophila immunity and shed light on the balance between these two arms of host defense depending on the invading pathogen.},
keywords = {Animals, Antimicrobial Cationic Peptides, Carrier Proteins, Cell Surface, Cellular, Enterococcus faecalis, ferrandon, Gram-Positive Bacteria, Gram-Positive Bacterial Infections, Host-Pathogen Interactions, Humoral, Immunity, Innate, M3i, Micrococcus luteus, Opsonin Proteins, Phagocytosis, Receptors, Signal Transduction, Solubility, Staphylococcus aureus},
pubstate = {published},
tppubtype = {article}
}
Irving Phil, Ubeda Jean-Michel, Doucet Daniel, Troxler Laurent, Lagueux Marie, Zachary Daniel, Hoffmann Jules A, Hetru Charles, Meister Marie
New insights into Drosophila larval haemocyte functions through genome-wide analysis Article de journal
Dans: Cell. Microbiol., vol. 7, no. 3, p. 335–350, 2005, ISSN: 1462-5814.
Résumé | Liens | BibTeX | Étiquettes: Animals, bioinformatic, Catechol Oxidase, Cell Lineage, Enzyme Precursors, Escherichia coli, Fat Body, Gene Expression Profiling, Genome, Hemocytes, hoffmann, Integrin alpha Chains, Integrins, Larva, M3i, Micrococcus luteus
@article{irving_new_2005,
title = {New insights into Drosophila larval haemocyte functions through genome-wide analysis},
author = {Phil Irving and Jean-Michel Ubeda and Daniel Doucet and Laurent Troxler and Marie Lagueux and Daniel Zachary and Jules A Hoffmann and Charles Hetru and Marie Meister},
doi = {10.1111/j.1462-5822.2004.00462.x},
issn = {1462-5814},
year = {2005},
date = {2005-03-01},
journal = {Cell. Microbiol.},
volume = {7},
number = {3},
pages = {335--350},
abstract = {Drosophila blood cells or haemocytes comprise three cell lineages, plasmatocytes, crystal cells and lamellocytes, involved in immune functions such as phagocytosis, melanisation and encapsulation. Transcriptional profiling of activities of distinct haemocyte populations and from naive or infected larvae, was performed to find genes contributing to haemocyte functions. Of the 13 000 genes represented on the microarray, over 2500 exhibited significantly enriched transcription in haemocytes. Among these were genes encoding integrins, peptidoglycan recognition proteins (PGRPs), scavenger receptors, lectins, cell adhesion molecules and serine proteases. One relevant outcome of this analysis was the gain of new insights into the lamellocyte encapsulation process. We showed that lamellocytes require betaPS integrin for encapsulation and that they transcribe one prophenoloxidase gene enabling them to produce the enzyme necessary for melanisation of the capsule. A second compelling observation was that following infection, the gene encoding the cytokine Spatzle was uniquely upregulated in haemocytes and not the fat body. This shows that Drosophila haemocytes produce a signal molecule ready to be activated through cleavage after pathogen recognition, informing distant tissues of infection.},
keywords = {Animals, bioinformatic, Catechol Oxidase, Cell Lineage, Enzyme Precursors, Escherichia coli, Fat Body, Gene Expression Profiling, Genome, Hemocytes, hoffmann, Integrin alpha Chains, Integrins, Larva, M3i, Micrococcus luteus},
pubstate = {published},
tppubtype = {article}
}
Tauszig-Delamasure Servane, Bilak Hana, Capovilla Maria, Hoffmann Jules A, Imler Jean-Luc
Drosophila MyD88 is required for the response to fungal and Gram-positive bacterial infections Article de journal
Dans: Nature Immunology, vol. 3, no. 1, p. 91–97, 2002, ISSN: 1529-2908.
Résumé | Liens | BibTeX | Étiquettes: Adaptor Proteins, Amino Acid, Animals, Antigens, Antimicrobial Cationic Peptides, Cell Surface, Chromosome Mapping, Differentiation, Disease Susceptibility, Enterococcus faecalis, Epistasis, Escherichia coli, Female, Gene Expression Regulation, Genes, Genetic, Genetically Modified, Gram-Negative Bacteria, hoffmann, Hypocreales, imler, Immunologic, Insect, Insect Proteins, M3i, Membrane Glycoproteins, Micrococcus luteus, Myeloid Differentiation Factor 88, Protein Structure, Protein-Serine-Threonine Kinases, Receptors, Recombinant Fusion Proteins, Sequence Alignment, Sequence Homology, Signal Transducing, Tertiary, Toll-Like Receptors, Transfection
@article{tauszig-delamasure_drosophila_2002,
title = {Drosophila MyD88 is required for the response to fungal and Gram-positive bacterial infections},
author = {Servane Tauszig-Delamasure and Hana Bilak and Maria Capovilla and Jules A Hoffmann and Jean-Luc Imler},
doi = {10.1038/ni747},
issn = {1529-2908},
year = {2002},
date = {2002-01-01},
journal = {Nature Immunology},
volume = {3},
number = {1},
pages = {91--97},
abstract = {We report here the identification and functional characterization of DmMyD88, a gene encoding the Drosophila homolog of mammalian MyD88. DmMyD88 combines a Toll-IL-1R homology (TIR) domain and a death domain. Overexpression of DmMyD88 was sufficient to induce expression of the antifungal peptide Drosomycin, and induction of Drosomycin was markedly reduced in DmMyD88-mutant flies. DmMyD88 interacted with Toll through its TIR domain and required the death domain proteins Tube and Pelle to activate expression of Drs, which encodes Drosomycin. DmMyD88-mutant flies were highly susceptible to infection by fungi and Gram-positive bacteria, but resisted Gram-negative bacterial infection much as did wild-type flies. Phenotypic comparison of DmMyD88-mutant flies and MyD88-deficient mice showed essential differences in the control of Gram-negative infection in insects and mammals.},
keywords = {Adaptor Proteins, Amino Acid, Animals, Antigens, Antimicrobial Cationic Peptides, Cell Surface, Chromosome Mapping, Differentiation, Disease Susceptibility, Enterococcus faecalis, Epistasis, Escherichia coli, Female, Gene Expression Regulation, Genes, Genetic, Genetically Modified, Gram-Negative Bacteria, hoffmann, Hypocreales, imler, Immunologic, Insect, Insect Proteins, M3i, Membrane Glycoproteins, Micrococcus luteus, Myeloid Differentiation Factor 88, Protein Structure, Protein-Serine-Threonine Kinases, Receptors, Recombinant Fusion Proteins, Sequence Alignment, Sequence Homology, Signal Transducing, Tertiary, Toll-Like Receptors, Transfection},
pubstate = {published},
tppubtype = {article}
}
Michel T, Reichhart Jean-Marc, Hoffmann Jules A, Royet Julien
Drosophila Toll is activated by Gram-positive bacteria through a circulating peptidoglycan recognition protein Article de journal
Dans: Nature, vol. 414, no. 6865, p. 756–759, 2001, ISSN: 0028-0836.
Résumé | Liens | BibTeX | Étiquettes: Amino Acid, Animals, Anti-Bacterial Agents, Anti-Infective Agents, Bacillus thuringiensis, Carrier Proteins, Cell Surface, Chromosome Mapping, Enterococcus faecalis, Fungi, Genes, Gram-Positive Bacteria, Hemolymph, hoffmann, Humans, Insect, Insect Proteins, M3i, Membrane Glycoproteins, Micrococcus luteus, Mutation, Receptors, reichhart, Sequence Homology, Toll-Like Receptors
@article{michel_drosophila_2001,
title = {Drosophila Toll is activated by Gram-positive bacteria through a circulating peptidoglycan recognition protein},
author = {T Michel and Jean-Marc Reichhart and Jules A Hoffmann and Julien Royet},
doi = {10.1038/414756a},
issn = {0028-0836},
year = {2001},
date = {2001-12-01},
journal = {Nature},
volume = {414},
number = {6865},
pages = {756--759},
abstract = {Microbial infection activates two distinct intracellular signalling cascades in the immune-responsive fat body of Drosophila. Gram-positive bacteria and fungi predominantly induce the Toll signalling pathway, whereas Gram-negative bacteria activate the Imd pathway. Loss-of-function mutants in either pathway reduce the resistance to corresponding infections. Genetic screens have identified a range of genes involved in these intracellular signalling cascades, but how they are activated by microbial infection is largely unknown. Activation of the transmembrane receptor Toll requires a proteolytically cleaved form of an extracellular cytokine-like polypeptide, Spätzle, suggesting that Toll does not itself function as a bona fide recognition receptor of microbial patterns. This is in apparent contrast with the mammalian Toll-like receptors and raises the question of which host molecules actually recognize microbial patterns to activate Toll through Spätzle. Here we present a mutation that blocks Toll activation by Gram-positive bacteria and significantly decreases resistance to this type of infection. The mutation semmelweis (seml) inactivates the gene encoding a peptidoglycan recognition protein (PGRP-SA). Interestingly, seml does not affect Toll activation by fungal infection, indicating the existence of a distinct recognition system for fungi to activate the Toll pathway.},
keywords = {Amino Acid, Animals, Anti-Bacterial Agents, Anti-Infective Agents, Bacillus thuringiensis, Carrier Proteins, Cell Surface, Chromosome Mapping, Enterococcus faecalis, Fungi, Genes, Gram-Positive Bacteria, Hemolymph, hoffmann, Humans, Insect, Insect Proteins, M3i, Membrane Glycoproteins, Micrococcus luteus, Mutation, Receptors, reichhart, Sequence Homology, Toll-Like Receptors},
pubstate = {published},
tppubtype = {article}
}
Hetru Charles, Letellier L, Oren Z, Hoffmann Jules A, Shai Y
Androctonin, a hydrophilic disulphide-bridged non-haemolytic anti-microbial peptide: a plausible mode of action Article de journal
Dans: Biochem. J., vol. 345 Pt 3, p. 653–664, 2000, ISSN: 0264-6021.
Résumé | BibTeX | Étiquettes: Adenosine Triphosphate, Anti-Bacterial Agents, Cations, Cell Membrane Permeability, Cytoplasm, Disulfides, Electron, Escherichia coli, Fluoresceins, Fluorescent Dyes, Fourier Transform Infrared, Gram-Negative Bacteria, hoffmann, Insect Proteins, Liposomes, M3i, Microbial Sensitivity Tests, Micrococcus luteus, Microscopy, oxygen, Phospholipids, Potassium, Proteins, spectroscopy
@article{hetru_androctonin_2000,
title = {Androctonin, a hydrophilic disulphide-bridged non-haemolytic anti-microbial peptide: a plausible mode of action},
author = {Charles Hetru and L Letellier and Z Oren and Jules A Hoffmann and Y Shai},
issn = {0264-6021},
year = {2000},
date = {2000-01-01},
journal = {Biochem. J.},
volume = {345 Pt 3},
pages = {653--664},
abstract = {Androctonin is a 25-residue non-haemolytic anti-microbial peptide isolated from the scorpion Androctonus australis and contains two disulphide bridges. Androctonin is different from known native anti-microbial peptides, being a relatively hydrophilic and non-amphipathic molecule. This raises the possibility that the target of androctonin might not be the bacterial membrane, shown to be a target for most amphipathic lytic peptides. To shed light on its mode of action on bacteria and its non-haemolytic activity, we synthesized androctonin, its fluorescent derivatives and its all-D-amino acid enantiomer. The enantiomer preserved high activity, suggesting a lipid-peptide interaction between androctonin and bacterial membranes. In Gram-positive and (at higher concentrations) Gram-negative bacteria, androctonin induced an immediate perturbation of the permeability properties of the cytoplasmic membrane of the bacterial energetic state, concomitant with perturbation of the morphology of the cell envelope as revealed by electron microscopy. Androctonin binds only to negatively charged lipid vesicles and induces the leakage of markers at high concentrations and with a slow kinetics, in contrast with amphipathic alpha-helical anti-microbial peptides that bind and permeate negatively charged vesicles, and to a smaller extent also zwitterionic ones. This might explain the selective lytic activity of androctonin towards bacteria but not red blood cells. Polarized attenuated total reflection-Fourier transform infrared spectroscopy revealed that androctonin adopts a beta-sheet structure in membranes and did not affect the lipid acyl chain order, which supports a detergent-like effect. The small size of androctonin, its hydrophilic character and its physicochemical properties are favourable features for its potential application as a replacement for commercially available antibiotics to which bacteria have developed resistance.},
keywords = {Adenosine Triphosphate, Anti-Bacterial Agents, Cations, Cell Membrane Permeability, Cytoplasm, Disulfides, Electron, Escherichia coli, Fluoresceins, Fluorescent Dyes, Fourier Transform Infrared, Gram-Negative Bacteria, hoffmann, Insect Proteins, Liposomes, M3i, Microbial Sensitivity Tests, Micrococcus luteus, Microscopy, oxygen, Phospholipids, Potassium, Proteins, spectroscopy},
pubstate = {published},
tppubtype = {article}
}
Levashina Elena A, Langley E, Green C, Gubb David, Ashburner M, Hoffmann Jules A, Reichhart Jean-Marc
Constitutive activation of toll-mediated antifungal defense in serpin-deficient Drosophila Article de journal
Dans: Science, vol. 285, no. 5435, p. 1917–1919, 1999, ISSN: 0036-8075.
Résumé | BibTeX | Étiquettes: Animals, Antifungal Agents, Antimicrobial Cationic Peptides, Body Patterning, Cell Surface, Escherichia coli, Genes, Hemolymph, hoffmann, Insect, Insect Proteins, M3i, Membrane Glycoproteins, Micrococcus luteus, Mutagenesis, Peptides, Receptors, Recombinant Fusion Proteins, reichhart, Serine Proteinase Inhibitors, Serpins, Signal Transduction, Toll-Like Receptors, Up-Regulation
@article{levashina_constitutive_1999,
title = {Constitutive activation of toll-mediated antifungal defense in serpin-deficient Drosophila},
author = {Elena A Levashina and E Langley and C Green and David Gubb and M Ashburner and Jules A Hoffmann and Jean-Marc Reichhart},
issn = {0036-8075},
year = {1999},
date = {1999-09-01},
journal = {Science},
volume = {285},
number = {5435},
pages = {1917--1919},
abstract = {The antifungal defense of Drosophila is controlled by the spaetzle/Toll/cactus gene cassette. Here, a loss-of-function mutation in the gene encoding a blood serine protease inhibitor, Spn43Ac, was shown to lead to constitutive expression of the antifungal peptide drosomycin, and this effect was mediated by the spaetzle and Toll gene products. Spaetzle was cleaved by proteolytic enzymes to its active ligand form shortly after immune challenge, and cleaved Spaetzle was constitutively present in Spn43Ac-deficient flies. Hence, Spn43Ac negatively regulates the Toll signaling pathway, and Toll does not function as a pattern recognition receptor in the Drosophila host defense.},
keywords = {Animals, Antifungal Agents, Antimicrobial Cationic Peptides, Body Patterning, Cell Surface, Escherichia coli, Genes, Hemolymph, hoffmann, Insect, Insect Proteins, M3i, Membrane Glycoproteins, Micrococcus luteus, Mutagenesis, Peptides, Receptors, Recombinant Fusion Proteins, reichhart, Serine Proteinase Inhibitors, Serpins, Signal Transduction, Toll-Like Receptors, Up-Regulation},
pubstate = {published},
tppubtype = {article}
}
Lamberty M, Ades S, Uttenweiler-Joseph S, Brookhart G, Bushey D, Hoffmann Jules A, Bulet Philippe
Insect immunity. Isolation from the lepidopteran Heliothis virescens of a novel insect defensin with potent antifungal activity Article de journal
Dans: J. Biol. Chem., vol. 274, no. 14, p. 9320–9326, 1999, ISSN: 0021-9258.
Résumé | BibTeX | Étiquettes: Amino Acid, Animals, Antifungal Agents, Capillary, Chromatography, Defensins, Electrophoresis, Escherichia coli, Hemolymph, High Pressure Liquid, hoffmann, Insect Proteins, Larva, Lepidoptera, M3i, Micrococcus luteus, Proteins, Sequence Homology
@article{lamberty_insect_1999,
title = {Insect immunity. Isolation from the lepidopteran Heliothis virescens of a novel insect defensin with potent antifungal activity},
author = {M Lamberty and S Ades and S Uttenweiler-Joseph and G Brookhart and D Bushey and Jules A Hoffmann and Philippe Bulet},
issn = {0021-9258},
year = {1999},
date = {1999-04-01},
journal = {J. Biol. Chem.},
volume = {274},
number = {14},
pages = {9320--9326},
abstract = {Lepidoptera have been reported to produce several antibacterial peptides in response to septic injury. However, in marked contrast to other insect groups, no inducible antifungal molecules had been described so far in this insect order. Surprisingly, also cysteine-rich antimicrobial peptides, which predominate in the antimicrobial defense of other insects, had not been discovered in Lepidoptera. Here we report the isolation from the hemolymph of immune induced larvae of the lepidopteran Heliothis virescens of a cysteine-rich molecule with exclusive antifungal activity. We have fully characterized this antifungal molecule, which has significant homology with the insect defensins, a large family of antibacterial peptides directed against Gram-positive strains. Interestingly, the novel peptide shows also similarities with the antifungal peptide drosomycin from Drosophila. Thus, Lepidoptera appear to have built their humoral immune response against bacteria on cecropins and attacins. In addition, we report that Lepidoptera have conferred antifungal properties to the well conserved structure of antibacterial insect defensins through amino acid replacements.},
keywords = {Amino Acid, Animals, Antifungal Agents, Capillary, Chromatography, Defensins, Electrophoresis, Escherichia coli, Hemolymph, High Pressure Liquid, hoffmann, Insect Proteins, Larva, Lepidoptera, M3i, Micrococcus luteus, Proteins, Sequence Homology},
pubstate = {published},
tppubtype = {article}
}
Lowenberger C A, Kamal S, Chiles J, Paskewitz S, Bulet Philippe, Hoffmann Jules A, Christensen B M
Mosquito-Plasmodium interactions in response to immune activation of the vector Article de journal
Dans: Exp. Parasitol., vol. 91, no. 1, p. 59–69, 1999, ISSN: 0014-4894.
Résumé | Liens | BibTeX | Étiquettes: Aedes, Animals, Anopheles, Culicidae, Defensins, Digestive System, Escherichia coli, Female, Genetic, Hemolymph, hoffmann, Insect Vectors, M3i, messenger, Micrococcus luteus, Plasmodium, Plasmodium berghei, Plasmodium gallinaceum, Proteins, Reverse Transcriptase Polymerase Chain Reaction, RNA, Transcription
@article{lowenberger_mosquito-plasmodium_1999,
title = {Mosquito-Plasmodium interactions in response to immune activation of the vector},
author = {C A Lowenberger and S Kamal and J Chiles and S Paskewitz and Philippe Bulet and Jules A Hoffmann and B M Christensen},
doi = {10.1006/expr.1999.4350},
issn = {0014-4894},
year = {1999},
date = {1999-01-01},
journal = {Exp. Parasitol.},
volume = {91},
number = {1},
pages = {59--69},
abstract = {During the development of Plasmodium sp. within the mosquito midgut, the parasite undergoes a series of developmental changes. The elongated ookinete migrates through the layers of the midgut where it forms the oocyst under the basal lamina. We demonstrate here that if Aedes aegypti or Anopheles gambiae, normally susceptible to Plasmodium gallinaceum and P. berghei, respectively, are immune activated by the injection of bacteria into the hemocoel, and subsequently are fed on an infectious bloodmeal, there is a significant reduction in the prevalence and mean intensity of infection of oocysts on the midgut. Only those mosquitoes immune activated prior to, or immediately after, parasite ingestion exhibit this reduction in parasite development. Mosquitoes immune activated 2-5 days after bloodfeeding show no differences in parasite burdens compared with naive controls. Northern analyses reveal that transcriptional activity for mosquito defensins is not detected in the whole bodies of Ae. aegypti from 4 h to 10 days after ingesting P. gallinaceum, suggesting that parasite ingestion, passage from the food bolus through the midgut, oocyst formation, and subsequent release of sporozoites into the hemolymph do not induce the production of defensin. However, reverse transcriptase-PCR of RNA isolated solely from the midguts of Ae. aegypti indicates that transcription of mosquito defensins occurs in the midguts of naive mosquitoes and those ingesting an infectious or noninfectious bloodmeal. Bacteria-challenged Ae. aegypti showed high levels of mature defensin in the hemolymph that correlate with a lower prevalence and mean intensity of infection with oocysts. Because few oocysts were found on the midgut of immune-activated mosquitoes, the data suggest that some factor, induced by bacterial challenge, kills the parasite at a preoocyst stage.},
keywords = {Aedes, Animals, Anopheles, Culicidae, Defensins, Digestive System, Escherichia coli, Female, Genetic, Hemolymph, hoffmann, Insect Vectors, M3i, messenger, Micrococcus luteus, Plasmodium, Plasmodium berghei, Plasmodium gallinaceum, Proteins, Reverse Transcriptase Polymerase Chain Reaction, RNA, Transcription},
pubstate = {published},
tppubtype = {article}
}
Braun A, Hoffmann Jules A, Meister Marie
Analysis of the Drosophila host defense in domino mutant larvae, which are devoid of hemocytes Article de journal
Dans: Proc. Natl. Acad. Sci. U.S.A., vol. 95, no. 24, p. 14337–14342, 1998, ISSN: 0027-8424.
Résumé | BibTeX | Étiquettes: Adipose Tissue, Animals, Candida, Escherichia coli, Fungal, Genotype, Hemocytes, hoffmann, Larva, M3i, Melanins, Micrococcus luteus, Spores
@article{braun_analysis_1998,
title = {Analysis of the Drosophila host defense in domino mutant larvae, which are devoid of hemocytes},
author = {A Braun and Jules A Hoffmann and Marie Meister},
issn = {0027-8424},
year = {1998},
date = {1998-11-01},
journal = {Proc. Natl. Acad. Sci. U.S.A.},
volume = {95},
number = {24},
pages = {14337--14342},
abstract = {We have analyzed the Drosophila immune response in domino mutant larvae, which are devoid of blood cells. The domino mutants have a good larval viability, but they die as prepupae. We show that, on immune challenge, induction of the genes encoding antimicrobial peptides in the fat body is not affected significantly in the mutant larvae, indicating that hemocytes are not essential in this process. The hemocoele of domino larvae contains numerous live microorganisms, the presence of which induces a weak antimicrobial response in the fat body. A full response is observed only after septic injury. We propose that the fat body cells are activated both by the presence of microorganisms and by injury and that injury potentiates the effect of microorganisms. Survival experiments after an immune challenge showed that domino mutants devoid of blood cells maintain a wild-type resistance to septic injury. This resistance was also observed in mutant larvae in which the synthesis of antibacterial peptides is impaired (immune deficiency larvae) and in mutants that are deficient for humoral melanization (Black cells larvae). However, if domino was combined with either the immune deficiency or the Black cell mutation, the resistance to septic injury was reduced severely. These results establish the relevance of the three immune reactions: phagocytosis, synthesis of antibacterial peptides, and melanization. By working in synergy, they provide Drosophila a highly effective defense against injury and/or infection.},
keywords = {Adipose Tissue, Animals, Candida, Escherichia coli, Fungal, Genotype, Hemocytes, hoffmann, Larva, M3i, Melanins, Micrococcus luteus, Spores},
pubstate = {published},
tppubtype = {article}
}
Richman A M, Bulet Philippe, Hetru Charles, Barillas-Mury Carolina, Hoffmann Jules A, Kafalos Fotis C
Inducible immune factors of the vector mosquito Anopheles gambiae: biochemical purification of a defensin antibacterial peptide and molecular cloning of preprodefensin cDNA Article de journal
Dans: Insect Mol. Biol., vol. 5, no. 3, p. 203–210, 1996, ISSN: 0962-1075.
Résumé | BibTeX | Étiquettes: Amino Acid, Animals, Anopheles, Base Sequence, Blood Bactericidal Activity, Blood Proteins, Cloning, Complementary, Defensins, DNA, Escherichia coli, Female, Gene Expression, Genes, hoffmann, Insect, Insect Vectors, Larva, M3i, Micrococcus luteus, Molecular, Sequence Homology
@article{richman_inducible_1996,
title = {Inducible immune factors of the vector mosquito Anopheles gambiae: biochemical purification of a defensin antibacterial peptide and molecular cloning of preprodefensin cDNA},
author = {A M Richman and Philippe Bulet and Charles Hetru and Carolina Barillas-Mury and Jules A Hoffmann and Fotis C Kafalos},
issn = {0962-1075},
year = {1996},
date = {1996-08-01},
journal = {Insect Mol. Biol.},
volume = {5},
number = {3},
pages = {203--210},
abstract = {Larvae of the mosquito vector of human malaria, Anopheles gambiae, were inoculated with bacteria and extracts were biochemically fractionated by reverse-phase HPLC. Multiple induced polypeptides and antibacterial activities were observed following bacterial infection, including a member of the insect defensin family of antibacterial proteins. A cDNA encoding An. gambiae preprodefensin was isolated using PCR primers based on phylogenetically conserved sequences. The mature peptide is highly conserved, but the signal and propeptide segments are not, relative to corresponding defensin sequences of other insects. Defensin expression is induced in response to bacterial infection, in both adult and larval stages. In contrast, pupae express defensin mRNA constitutively. Defensin expression may prove a valuable molecular marker to monitor the An. gambiae host response to infection by parasitic protozoa of medical importance.},
keywords = {Amino Acid, Animals, Anopheles, Base Sequence, Blood Bactericidal Activity, Blood Proteins, Cloning, Complementary, Defensins, DNA, Escherichia coli, Female, Gene Expression, Genes, hoffmann, Insect, Insect Vectors, Larva, M3i, Micrococcus luteus, Molecular, Sequence Homology},
pubstate = {published},
tppubtype = {article}
}
Lowenberger C A, Ferdig M T, Bulet Philippe, Khalili S, Hoffmann Jules A, Christensen B M
Aedes aegypti: induced antibacterial proteins reduce the establishment and development of Brugia malayi Article de journal
Dans: Exp. Parasitol., vol. 83, no. 2, p. 191–201, 1996, ISSN: 0014-4894.
Résumé | Liens | BibTeX | Étiquettes: Aedes, Analysis of Variance, Animals, Anti-Bacterial Agents, Base Sequence, Blood Proteins, Blotting, Brugia malayi, Culicidae, Defensins, DNA, Escherichia coli, Fat Body, Genetic, Gerbillinae, hoffmann, M3i, Micrococcus luteus, Microfilaria, Northern, RNA, Transcription
@article{lowenberger_aedes_1996,
title = {Aedes aegypti: induced antibacterial proteins reduce the establishment and development of Brugia malayi},
author = {C A Lowenberger and M T Ferdig and Philippe Bulet and S Khalili and Jules A Hoffmann and B M Christensen},
doi = {10.1006/expr.1996.0066},
issn = {0014-4894},
year = {1996},
date = {1996-07-01},
journal = {Exp. Parasitol.},
volume = {83},
number = {2},
pages = {191--201},
abstract = {The effect of host immune activation on the development of Brugia malayi in one susceptible and four refractory strains of Aedes aegypti and in Armigeres subalbatus was assessed. A. aegypti that were immune activated by the injection of saline or bacteria 24 hr before feeding on a B. malayi-infected gerbil had significantly reduced prevalences and mean intensities of infection from those of naive controls when exposed to bloodmeals with low (105 mf/20 microliters) and medium (160 mf/20 microliters) microfilaremias. At a higher microfilaremia (237 mf/20 microliters) there were no significant differences in mean intensities, suggesting that the number of parasites ingested may affect the host's ability to mount an effective defense response. Because the major immune proteins in A. aegypti are defensins, we did Northern analyses of fat body RNA 8 hr after immune activation or bloodfeeding. All mosquitoes demonstrated rapid transcriptional activity for defensins following immune activation by intrathoracic inoculation with either saline or bacteria. However, no strain of A. aegypti, susceptible or refractory to B. malayi, nor Ar. subalbatus produced defensin transcripts after bloodfeeding on an uninfected or a B. malayi-infected gerbil. These data suggest that inducible immune proteins of mosquitoes can reduce the prevalence and mean intensity of infections with ingested parasites, but these proteins are not expressed routinely after parasite ingestion and midgut penetration and probably do not contribute to existing refractory mechanisms. Immune proteins such as defensins, however, represent potential candidates to genetically engineer mosquitoes for resistance to filarial worms.},
keywords = {Aedes, Analysis of Variance, Animals, Anti-Bacterial Agents, Base Sequence, Blood Proteins, Blotting, Brugia malayi, Culicidae, Defensins, DNA, Escherichia coli, Fat Body, Genetic, Gerbillinae, hoffmann, M3i, Micrococcus luteus, Microfilaria, Northern, RNA, Transcription},
pubstate = {published},
tppubtype = {article}
}
Lowenberger C, Bulet Philippe, Charlet Maurice, Hetru Charles, Hodgeman B, Christensen B M, Hoffmann Jules A
Insect immunity: isolation of three novel inducible antibacterial defensins from the vector mosquito, Aedes aegypti Article de journal
Dans: Insect Biochem. Mol. Biol., vol. 25, no. 7, p. 867–873, 1995, ISSN: 0965-1748.
Résumé | BibTeX | Étiquettes: Aedes, Amino Acid, Animals, Anti-Bacterial Agents, Blood Proteins, Defensins, Escherichia coli, Gram-Negative Bacteria, Gram-Positive Bacteria, hoffmann, Immunity, Insect Vectors, M3i, Micrococcus luteus, Sequence Homology, Stereoisomerism
@article{lowenberger_insect_1995,
title = {Insect immunity: isolation of three novel inducible antibacterial defensins from the vector mosquito, Aedes aegypti},
author = {C Lowenberger and Philippe Bulet and Maurice Charlet and Charles Hetru and B Hodgeman and B M Christensen and Jules A Hoffmann},
issn = {0965-1748},
year = {1995},
date = {1995-07-01},
journal = {Insect Biochem. Mol. Biol.},
volume = {25},
number = {7},
pages = {867--873},
abstract = {The injection of Escherichia coli and Micrococcus luteus into the hemocoel of Aedes aegypti induces a potent antibacterial activity in the hemolymph. We have purified and fully characterized three 40-residue antibacterial peptides from the hemolymph of bacteria-challenged mosquitoes that are absent in naive mosquitoes. The peptides are potently active against Gram-positive bacteria and against one of the Gram-negative bacteria that were tested. The amino acid sequences clearly show that the three peptides are novel isoforms of the insect defensin family of antibacterial peptides. They differ from each other by one or two amino acid residues. We present here the complete amino acid sequences of the three isoforms and the activity spectrum of the predominant Aedes defensin.},
keywords = {Aedes, Amino Acid, Animals, Anti-Bacterial Agents, Blood Proteins, Defensins, Escherichia coli, Gram-Negative Bacteria, Gram-Positive Bacteria, hoffmann, Immunity, Insect Vectors, M3i, Micrococcus luteus, Sequence Homology, Stereoisomerism},
pubstate = {published},
tppubtype = {article}
}