Intranet
Access
Contact
Publications
2023
C Lutrat, M Burckbuchler, RP Olmo, R Beugnon, A Fontaine, OS Akbari, R Argiles-Herrero, T Baldet, J Bouyer, E Marois
Combining two Genetic Sexing Strains allows sorting of non-transgenic males for Aedes genetic control Journal Article
In: Commun Biol., vol. 6, iss. 1, pp. 646, 2023.
Abstract | Links | BibTeX | Tags: Aedes, M3i, marois, mosquitoes, Olmo, vectoring
@article{Lutrat2023,
title = {Combining two Genetic Sexing Strains allows sorting of non-transgenic males for Aedes genetic control},
author = {Lutrat C and Burckbuchler M and Olmo RP and Beugnon R and Fontaine A and Akbari OS and Argiles-Herrero R and Baldet T and Bouyer J and Marois E},
url = {https://www.nature.com/articles/s42003-023-05030-7},
doi = {10.1038/s42003-023-05030-7},
year = {2023},
date = {2023-06-16},
urldate = {2023-06-16},
journal = {Commun Biol.},
volume = {6},
issue = {1},
pages = {646},
abstract = {Chemical control of disease vectoring mosquitoes Aedes albopictus and Aedes aegypti is costly, unsustainable, and increasingly ineffective due to the spread of insecticide resistance. The Sterile Insect Technique is a valuable alternative but is limited by slow, error-prone, and wasteful sex-separation methods. Here, we present four Genetic Sexing Strains (two for each Aedes species) based on fluorescence markers linked to the m and M sex loci, allowing for the isolation of transgenic males. Furthermore, we demonstrate how combining these sexing strains enables the production of non-transgenic males. In a mass-rearing facility, 100,000 first instar male larvae could be sorted in under 1.5 h with an estimated 0.01–0.1% female contamination on a single machine. Cost-efficiency analyses revealed that using these strains could result in important savings while setting up and running a mass-rearing facility. Altogether, these Genetic Sexing Strains should enable a major upscaling in control programmes against these important vectors.},
keywords = {Aedes, M3i, marois, mosquitoes, Olmo, vectoring},
pubstate = {published},
tppubtype = {article}
}
Chemical control of disease vectoring mosquitoes Aedes albopictus and Aedes aegypti is costly, unsustainable, and increasingly ineffective due to the spread of insecticide resistance. The Sterile Insect Technique is a valuable alternative but is limited by slow, error-prone, and wasteful sex-separation methods. Here, we present four Genetic Sexing Strains (two for each Aedes species) based on fluorescence markers linked to the m and M sex loci, allowing for the isolation of transgenic males. Furthermore, we demonstrate how combining these sexing strains enables the production of non-transgenic males. In a mass-rearing facility, 100,000 first instar male larvae could be sorted in under 1.5 h with an estimated 0.01–0.1% female contamination on a single machine. Cost-efficiency analyses revealed that using these strains could result in important savings while setting up and running a mass-rearing facility. Altogether, these Genetic Sexing Strains should enable a major upscaling in control programmes against these important vectors.
2021
Leite Thiago H J F, Ferreira Alvaro G A, Imler Jean-Luc, Marques João T
Distinct Roles of Hemocytes at Different Stages of Infection by Dengue and Zika Viruses in Aedes aegypti Mosquitoes Journal Article
In: Frontiers in immunology, vol. 12, pp. 660873, 2021.
Abstract | Links | BibTeX | Tags: Aedes, Dengue, Hemocytes, imler, innate immunity, M3i, Marques, Zika
@article{Leite2021,
title = {Distinct Roles of Hemocytes at Different Stages of Infection by Dengue and Zika Viruses in Aedes aegypti Mosquitoes},
author = {Thiago H J F Leite and Alvaro G A Ferreira and Jean-Luc Imler and João T Marques},
url = {https://www.frontiersin.org/articles/10.3389/fimmu.2021.660873/full},
doi = {10.3389/fimmu.2021.660873},
year = {2021},
date = {2021-05-13},
journal = {Frontiers in immunology},
volume = {12},
pages = {660873},
abstract = {Aedes aegypti mosquitoes are vectors for arboviruses of medical importance such as dengue (DENV) and Zika (ZIKV) viruses. Different innate immune pathways contribute to the control of arboviruses in the mosquito vector including RNA interference, Toll and Jak- STAT pathways. However, the role of cellular responses mediated by circulating macrophage-like cells known as hemocytes remains unclear. Here we show that hemocytes are recruited to the midgut of Ae. aegypti mosquitoes in response to DENV or ZIKV. Blockade of the phagocytic function of hemocytes using latex beads induced increased accumulation of hemocytes in the midgut and a reduction in virus infection levels in this organ. In contrast, inhibition of phagocytosis by hemocytes led to increased systemic dissemination and replication of DENV and ZIKV. Hence, our work reveals a dual role for hemocytes in Ae. aegypti mosquitoes, whereby phagocytosis is not required to control viral infection in the midgut but is essential to restrict systemic dissemination. Further understanding of the mechanism behind this duality could help the design of vector-based strategies to prevent transmission of arboviruses.},
keywords = {Aedes, Dengue, Hemocytes, imler, innate immunity, M3i, Marques, Zika},
pubstate = {published},
tppubtype = {article}
}
Aedes aegypti mosquitoes are vectors for arboviruses of medical importance such as dengue (DENV) and Zika (ZIKV) viruses. Different innate immune pathways contribute to the control of arboviruses in the mosquito vector including RNA interference, Toll and Jak- STAT pathways. However, the role of cellular responses mediated by circulating macrophage-like cells known as hemocytes remains unclear. Here we show that hemocytes are recruited to the midgut of Ae. aegypti mosquitoes in response to DENV or ZIKV. Blockade of the phagocytic function of hemocytes using latex beads induced increased accumulation of hemocytes in the midgut and a reduction in virus infection levels in this organ. In contrast, inhibition of phagocytosis by hemocytes led to increased systemic dissemination and replication of DENV and ZIKV. Hence, our work reveals a dual role for hemocytes in Ae. aegypti mosquitoes, whereby phagocytosis is not required to control viral infection in the midgut but is essential to restrict systemic dissemination. Further understanding of the mechanism behind this duality could help the design of vector-based strategies to prevent transmission of arboviruses.
2003
Luna C, Hoa N T, Zhang J, Kanzok S M, Brown S E, Imler Jean-Luc, Knudson D L, Zheng L
Characterization of three Toll-like genes from mosquito Aedes aegypti Journal Article
In: Insect Molecular Biology, vol. 12, no. 1, pp. 67–74, 2003, ISSN: 0962-1075.
Abstract | BibTeX | Tags: Aedes, Animals, Base Sequence, Cell Surface, Chimera, Cloning, Developmental, Female, Gene Expression Regulation, Genetic, imler, Insect Proteins, M3i, Male, messenger, Models, Molecular, Mutagenesis, Promoter Regions, Receptors, Reverse Transcriptase Polymerase Chain Reaction, RNA, Sequence Alignment, Signal Transduction, Site-Directed, Transfection
@article{luna_characterization_2003,
title = {Characterization of three Toll-like genes from mosquito Aedes aegypti},
author = {C Luna and N T Hoa and J Zhang and S M Kanzok and S E Brown and Jean-Luc Imler and D L Knudson and L Zheng},
issn = {0962-1075},
year = {2003},
date = {2003-02-01},
journal = {Insect Molecular Biology},
volume = {12},
number = {1},
pages = {67--74},
abstract = {Three Toll-related genes (AeToll1A, AeToll1B and AeToll5) were cloned and characterized from the yellow fever vector mosquito, Aedes aegypti. All three genes exhibited high levels of amino acid sequence similarity with Drosophila melanogaster (Dm)Toll1 and DmTehao (Toll5). AeToll1A and AeToll1B are 1124 and 1076 amino acid residues long, respectively. Both contain a carboxyl extension downstream of the Toll/interleukin-1 receptor (TIR) domain. AeToll5 is 1007 residues long and, like DmTehao, lacks the carboxyl terminal extension. Expression of these three genes was examined throughout development and after immune challenge. Both AeToll1A and AeToll5, like their Drosophila counterparts, activate transcription of drosomycin promoter in both Aedes and Drosophila cell lines. Deletion of the carboxyl extension of AeToll1A did not result in a further elevated level of the antifungal response. The intracellular signalling process appears to be species specific based on two observations. (1) DmToll is completely inactive in an Aedes cell line, suggesting a higher specificity requirement for DmToll in the intracellular signalling process. (2) Only one of three amino acid residues essential for DmToll function is required for AeToll1A function.},
keywords = {Aedes, Animals, Base Sequence, Cell Surface, Chimera, Cloning, Developmental, Female, Gene Expression Regulation, Genetic, imler, Insect Proteins, M3i, Male, messenger, Models, Molecular, Mutagenesis, Promoter Regions, Receptors, Reverse Transcriptase Polymerase Chain Reaction, RNA, Sequence Alignment, Signal Transduction, Site-Directed, Transfection},
pubstate = {published},
tppubtype = {article}
}
Three Toll-related genes (AeToll1A, AeToll1B and AeToll5) were cloned and characterized from the yellow fever vector mosquito, Aedes aegypti. All three genes exhibited high levels of amino acid sequence similarity with Drosophila melanogaster (Dm)Toll1 and DmTehao (Toll5). AeToll1A and AeToll1B are 1124 and 1076 amino acid residues long, respectively. Both contain a carboxyl extension downstream of the Toll/interleukin-1 receptor (TIR) domain. AeToll5 is 1007 residues long and, like DmTehao, lacks the carboxyl terminal extension. Expression of these three genes was examined throughout development and after immune challenge. Both AeToll1A and AeToll5, like their Drosophila counterparts, activate transcription of drosomycin promoter in both Aedes and Drosophila cell lines. Deletion of the carboxyl extension of AeToll1A did not result in a further elevated level of the antifungal response. The intracellular signalling process appears to be species specific based on two observations. (1) DmToll is completely inactive in an Aedes cell line, suggesting a higher specificity requirement for DmToll in the intracellular signalling process. (2) Only one of three amino acid residues essential for DmToll function is required for AeToll1A function.
1999
Lowenberger C A, Smartt C T, Bulet Philippe, Ferdig M T, Severson D W, Hoffmann Jules A, Christensen B M
Insect immunity: molecular cloning, expression, and characterization of cDNAs and genomic DNA encoding three isoforms of insect defensin in Aedes aegypti Journal Article
In: Insect Mol. Biol., vol. 8, no. 1, pp. 107–118, 1999, ISSN: 0962-1075.
Abstract | BibTeX | Tags: Aedes, Amino Acid, Animals, Base Sequence, Blotting, Chromosome Mapping, Cloning, Complementary, Defensins, DNA, Gene Expression, Hemolymph, hoffmann, M3i, Molecular, Northern, Protein Isoforms, Proteins, Sequence Homology
@article{lowenberger_insect_1999,
title = {Insect immunity: molecular cloning, expression, and characterization of cDNAs and genomic DNA encoding three isoforms of insect defensin in Aedes aegypti},
author = {C A Lowenberger and C T Smartt and Philippe Bulet and M T Ferdig and D W Severson and Jules A Hoffmann and B M Christensen},
issn = {0962-1075},
year = {1999},
date = {1999-02-01},
journal = {Insect Mol. Biol.},
volume = {8},
number = {1},
pages = {107--118},
abstract = {Aedes aegypti were immune activated by injection with bacteria, and the expression of insect defensins was measured over time. Northern analyses indicated that defensin transcriptional activity continued for at least 21 days after bacterial injection, and up to 10 days after saline inoculation. Mature defensin levels in the haemolymph reached approximately 45 microM at 24 h post inoculation. cDNAs encoding the preprodefensins of three previously described mature Ae. aegypti defensins were amplified by PCR, cloned and sequenced. Genomic clones were amplified using primers designed against the cDNA sequence. Sequence comparison indicates that there is significant inter- and intra-isoform variability in the signal peptide and prodefensin sequences of defensin genes. Preprodefensin sequences of isoforms A and B are very similar, consisting of a signal peptide region of twenty amino acids, a prodefensin region of thirty-eight amino acids and a forty amino acid mature peptide domain. The sequence encoding isoform C is significantly different, comprising a signal peptide region of twenty-three amino acids, a prodefensin region of thirty-six amino acids, and the mature protein domain of forty amino acids. Analysis of the genomic clones of each isoform revealed one intron spatially conserved in the prodefensin region of all sequences. The intron in isoforms A and B is 64 nt long, and except for a 4 nt substitution in one clone, these intron sequences are identical. The intron in isoform C is 76 nt long and does not share significant identity with the intron sequences of isoforms A or B. The defensin gene mapped to chromosome 3, between two known loci, blt and LF168.},
keywords = {Aedes, Amino Acid, Animals, Base Sequence, Blotting, Chromosome Mapping, Cloning, Complementary, Defensins, DNA, Gene Expression, Hemolymph, hoffmann, M3i, Molecular, Northern, Protein Isoforms, Proteins, Sequence Homology},
pubstate = {published},
tppubtype = {article}
}
Aedes aegypti were immune activated by injection with bacteria, and the expression of insect defensins was measured over time. Northern analyses indicated that defensin transcriptional activity continued for at least 21 days after bacterial injection, and up to 10 days after saline inoculation. Mature defensin levels in the haemolymph reached approximately 45 microM at 24 h post inoculation. cDNAs encoding the preprodefensins of three previously described mature Ae. aegypti defensins were amplified by PCR, cloned and sequenced. Genomic clones were amplified using primers designed against the cDNA sequence. Sequence comparison indicates that there is significant inter- and intra-isoform variability in the signal peptide and prodefensin sequences of defensin genes. Preprodefensin sequences of isoforms A and B are very similar, consisting of a signal peptide region of twenty amino acids, a prodefensin region of thirty-eight amino acids and a forty amino acid mature peptide domain. The sequence encoding isoform C is significantly different, comprising a signal peptide region of twenty-three amino acids, a prodefensin region of thirty-six amino acids, and the mature protein domain of forty amino acids. Analysis of the genomic clones of each isoform revealed one intron spatially conserved in the prodefensin region of all sequences. The intron in isoforms A and B is 64 nt long, and except for a 4 nt substitution in one clone, these intron sequences are identical. The intron in isoform C is 76 nt long and does not share significant identity with the intron sequences of isoforms A or B. The defensin gene mapped to chromosome 3, between two known loci, blt and LF168.
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 Journal Article
In: Exp. Parasitol., vol. 91, no. 1, pp. 59–69, 1999, ISSN: 0014-4894.
Abstract | Links | BibTeX | Tags: 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}
}
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.
1998
Shahabuddin M, Fields I, Bulet Philippe, Hoffmann Jules A, Miller L H
Plasmodium gallinaceum: differential killing of some mosquito stages of the parasite by insect defensin Journal Article
In: Exp. Parasitol., vol. 89, no. 1, pp. 103–112, 1998, ISSN: 0014-4894.
Abstract | Links | BibTeX | Tags: Aedes, Animals, Anti-Infective Agents, Blood Proteins, Defensins, Diptera, hoffmann, Insect Vectors, insects, M3i, Plasmodium gallinaceum, Zygote
@article{shahabuddin_plasmodium_1998,
title = {Plasmodium gallinaceum: differential killing of some mosquito stages of the parasite by insect defensin},
author = {M Shahabuddin and I Fields and Philippe Bulet and Jules A Hoffmann and L H Miller},
doi = {10.1006/expr.1998.4212},
issn = {0014-4894},
year = {1998},
date = {1998-05-01},
journal = {Exp. Parasitol.},
volume = {89},
number = {1},
pages = {103--112},
abstract = {We examined several insect antimicrobial peptides to study their effect on Plasmodium gallinaceum zygotes, ookinetes, oocysts, and sporozoites. Only two insect defensins-Aeschna cyanea (dragon fly) and Phormia terranovae (flesh fly)-had a profound toxic effect on the oocysts in Aedes aegypti and on isolated sporozoites. The defensins affected the oocysts in a time-dependent manner. Injecting the peptide into the hemolymph 1 or 2 days after an infectious blood meal had no significant effect on prevalence of infection or relative oocyst density per mosquito. When injected 3 days after parasite ingestion, the relative oocyst density was significantly reduced. Injection on day 4 or later damaged the developing oocysts, although the oocysts density per mosquito was not significantly different when examined on day 8. The oocysts were swollen or had extensive internal vacuolization. The peptides had no detectable effect on the early stages of the parasite: the zygotes and ookinetes tested in vitro. Both the defensins were highly toxic to isolated sporozoites in vitro as indicated by disruption of the membrane permeability barrier, a change in morphology, and loss of motility. In contrast to the toxicity of cecropin and magainin for mosquitoes, defensin, at concentrations that kill parasites, is not toxic to mosquitoes, suggesting that defensin should be studied further as a potential molecule to block sporogonic development of Plasmodium.},
keywords = {Aedes, Animals, Anti-Infective Agents, Blood Proteins, Defensins, Diptera, hoffmann, Insect Vectors, insects, M3i, Plasmodium gallinaceum, Zygote},
pubstate = {published},
tppubtype = {article}
}
We examined several insect antimicrobial peptides to study their effect on Plasmodium gallinaceum zygotes, ookinetes, oocysts, and sporozoites. Only two insect defensins-Aeschna cyanea (dragon fly) and Phormia terranovae (flesh fly)-had a profound toxic effect on the oocysts in Aedes aegypti and on isolated sporozoites. The defensins affected the oocysts in a time-dependent manner. Injecting the peptide into the hemolymph 1 or 2 days after an infectious blood meal had no significant effect on prevalence of infection or relative oocyst density per mosquito. When injected 3 days after parasite ingestion, the relative oocyst density was significantly reduced. Injection on day 4 or later damaged the developing oocysts, although the oocysts density per mosquito was not significantly different when examined on day 8. The oocysts were swollen or had extensive internal vacuolization. The peptides had no detectable effect on the early stages of the parasite: the zygotes and ookinetes tested in vitro. Both the defensins were highly toxic to isolated sporozoites in vitro as indicated by disruption of the membrane permeability barrier, a change in morphology, and loss of motility. In contrast to the toxicity of cecropin and magainin for mosquitoes, defensin, at concentrations that kill parasites, is not toxic to mosquitoes, suggesting that defensin should be studied further as a potential molecule to block sporogonic development of Plasmodium.
1996
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 Journal Article
In: Exp. Parasitol., vol. 83, no. 2, pp. 191–201, 1996, ISSN: 0014-4894.
Abstract | Links | BibTeX | Tags: 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}
}
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.
1995
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 Journal Article
In: Insect Biochem. Mol. Biol., vol. 25, no. 7, pp. 867–873, 1995, ISSN: 0965-1748.
Abstract | BibTeX | Tags: 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}
}
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.
