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García-Longoria L, Ahrén D, Berthomieu A, Kalbskopf V, Rivero A, Hellgren O. Immune gene expression in the mosquito vector Culex quinquefasciatus during an avian malaria infection. Mol Ecol 2023; 32:904-919. [PMID: 36448733 PMCID: PMC10108303 DOI: 10.1111/mec.16799] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 11/23/2022] [Accepted: 11/24/2022] [Indexed: 12/02/2022]
Abstract
Plasmodium relictum is the most widespread avian malaria parasite in the world. It is listed as one of the 100 most dangerous invasive species, having been responsible for the extinction of several endemic bird species, and the near-demise of several others. Here we present the first transcriptomic study focused on the effect of P. relictum on the immune system of its vector (the mosquito Culex quinquefasciatus) at different times post-infection. We show that over 50% of immune genes identified as being part of the Toll pathway and 30%-40% of the immune genes identified within the Imd pathway are overexpressed during the critical period spanning the parasite's oocyst and sporozoite formation (8-12 days), revealing the crucial role played by both these pathways in this natural mosquito-Plasmodium combination. Comparison of infected mosquitoes with their uninfected counterparts also revealed some unexpected immune RNA expression patterns earlier and later in the infection: significant differences in expression of several immune effectors were observed as early as 30 min after ingestion of the infected blood meal. In addition, in the later stages of the infection (towards the end of the mosquito lifespan), we observed an unexpected increase in immune investment in uninfected, but not in infected, mosquitoes. In conclusion, our work extends the comparative transcriptomic analyses of malaria-infected mosquitoes beyond human and rodent parasites and provides insights into the degree of conservation of immune pathways and into the selective pressures exerted by Plasmodium parasites on their vectors.
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Affiliation(s)
- Luz García-Longoria
- Department of Anatomy, Cellular Biology and Zoology, University of Extremadura, Badajoz, Spain
| | - Dag Ahrén
- Molecular Ecology and Evolution Lab, Department of Biology, Lund University, Lund, Sweden
| | | | - Victor Kalbskopf
- Molecular Ecology and Evolution Lab, Department of Biology, Lund University, Lund, Sweden
| | - Ana Rivero
- MIVEGEC (CNRS, Université de Montpellier, IRD), Montpellier, France
| | - Olof Hellgren
- Molecular Ecology and Evolution Lab, Department of Biology, Lund University, Lund, Sweden
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2
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Villa M, Buysse M, Berthomieu A, Rivero A. The transmission-blocking effects of antimalarial drugs revisited: fitness costs and sporontocidal effects of artesunate and sulfadoxine-pyrimethamine. Int J Parasitol 2021; 51:279-289. [PMID: 33508331 DOI: 10.1016/j.ijpara.2020.09.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Revised: 09/22/2020] [Accepted: 09/23/2020] [Indexed: 12/31/2022]
Abstract
Assays used to evaluate the transmission-blocking activity of antimalarial drugs are largely focused on their potential to inhibit or reduce the infectivity of gametocytes, the blood stages of the parasite that are responsible for the onward transmission to the mosquito vector. For this purpose, the drug is administered concomitantly with gametocyte-infected blood, and the results are evaluated as the percentage of reduction in the number of oocysts in the mosquito midgut. We report the results of a series of experiments that explore the transmission-blocking potential of two key antimalarial drugs, artesunate and sulfadoxine-pyrimethamine, when administered to mosquitoes already infected from a previous blood meal. For this purpose, uninfected mosquitoes and mosquitoes carrying a 6 day old Plasmodium relictum infection (early oocyst stages) were allowed to feed either on a drug-treated or an untreated host in a fully factorial experiment. This protocol allowed us to bypass the gametocyte stages and establish whether the drugs have a sporontocidal effect, i.e. whether they are able to arrest the ongoing development of oocysts and sporozoites, as would be the case when a mosquito takes a post-infection treated blood meal. In a separate experiment, we also explored whether a drug-treated blood meal impacted key life history traits of the mosquito relevant for transmission, and if this depended on their infection status. Our results showed that feeding on an artesunate- or sulfadoxine-pyrimethamine-treated hosts has no epidemiologically relevant effects on the fitness of infected or uninfected mosquitoes. In contrast, when infected mosquitoes fed on an sulfadoxine-pyrimethamine-treated host, we observed both a significant increase in the number of oocysts in the midgut, and a drastic decrease in both sporozoite prevalence (-30%) and burden (-80%) compared with the untreated controls. We discuss the potential mechanisms underlying these seemingly contradictory results and contend that, provided the results are translatable to human malaria, the potential epidemiological and evolutionary consequences of the current preventive use of sulfadoxine-pyrimethamine in malaria-endemic countries could be substantial.
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Affiliation(s)
- M Villa
- MIVEGEC (CNRS - IRD - Université de Montpellier), France.
| | - M Buysse
- MIVEGEC (CNRS - IRD - Université de Montpellier), France
| | - A Berthomieu
- MIVEGEC (CNRS - IRD - Université de Montpellier), France; CREES (Centre d'Écologie et Évolution de la Santé, Montpellier), 911 avenue Agropolis, 34394 Montpellier, France
| | - A Rivero
- MIVEGEC (CNRS - IRD - Université de Montpellier), France; CREES (Centre d'Écologie et Évolution de la Santé, Montpellier), 911 avenue Agropolis, 34394 Montpellier, France
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3
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Milesi P, Assogba BS, Atyame CM, Pocquet N, Berthomieu A, Unal S, Makoundou P, Weill M, Labbé P. The evolutionary fate of heterogeneous gene duplications: A precarious overdominant equilibrium between environment, sublethality and complementation. Mol Ecol 2017; 27:493-507. [PMID: 29230902 DOI: 10.1111/mec.14463] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 11/08/2017] [Accepted: 11/25/2017] [Indexed: 11/30/2022]
Abstract
Gene duplications occur at a high rate. Although most appear detrimental, some homogeneous duplications (identical gene copies) can be selected for beneficial increase in produced proteins. Heterogeneous duplications, which combine divergent alleles of a single locus, are seldom studied due to the paucity of empirical data. We investigated their role in an ongoing adaptive process at the ace-1 locus in Culex pipiens mosquitoes. We assessed the worldwide diversity of the ace-1 alleles (single-copy, susceptible S and insecticide-resistant R, and duplicated D that pair one S and one R copy), analysed their phylogeography and measured their fitness to understand their early dynamics using population genetics models. It provides a coherent and comprehensive evolutionary scenario. We show that D alleles are present in most resistant populations and display a higher diversity than R alleles (27 vs. 4). Most appear to result from independent unequal crossing-overs between local single-copy alleles, suggesting a recurrent process. Most duplicated alleles have a limited geographic distribution, probably resulting from their homozygous sublethality (HS phenotype). In addition, heterozygotes carrying different HS D alleles showed complementation, indicating different recessive lethal mutations. Due to mosaic insecticide control practices, balancing selection (overdominance) plays a key role in the early dynamics of heterogeneous duplicated alleles; it also favours a high local polymorphism of HS D alleles in natural populations (overdominance reinforced by complementation). Overall, our study shows that the evolutionary fate of heterogeneous duplications (and their long-term role) depends on finely balanced selective pressures due to the environment and to their genomic structure.
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Affiliation(s)
- Pascal Milesi
- ISEM Institut des Sciences de l'Evolution de Montpellier (CNRS-Université de Montpellier-IRD-EPHE), Montpellier, France
| | - Benoît S Assogba
- ISEM Institut des Sciences de l'Evolution de Montpellier (CNRS-Université de Montpellier-IRD-EPHE), Montpellier, France
| | - Célestine M Atyame
- ISEM Institut des Sciences de l'Evolution de Montpellier (CNRS-Université de Montpellier-IRD-EPHE), Montpellier, France
| | - Nicolas Pocquet
- UMR MIVEGEC Maladies infectieuses et vecteurs: écologie, génétique, évolution et contrôle (CNRS-Université de Montpellier-IRD), Montpellier, France
| | - Arnaud Berthomieu
- ISEM Institut des Sciences de l'Evolution de Montpellier (CNRS-Université de Montpellier-IRD-EPHE), Montpellier, France
| | - Sandra Unal
- ISEM Institut des Sciences de l'Evolution de Montpellier (CNRS-Université de Montpellier-IRD-EPHE), Montpellier, France
| | - Patrick Makoundou
- ISEM Institut des Sciences de l'Evolution de Montpellier (CNRS-Université de Montpellier-IRD-EPHE), Montpellier, France
| | - Mylène Weill
- ISEM Institut des Sciences de l'Evolution de Montpellier (CNRS-Université de Montpellier-IRD-EPHE), Montpellier, France
| | - Pierrick Labbé
- ISEM Institut des Sciences de l'Evolution de Montpellier (CNRS-Université de Montpellier-IRD-EPHE), Montpellier, France
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Assogba BS, Milesi P, Djogbénou LS, Berthomieu A, Makoundou P, Baba-Moussa LS, Fiston-Lavier AS, Belkhir K, Labbé P, Weill M. The ace-1 Locus Is Amplified in All Resistant Anopheles gambiae Mosquitoes: Fitness Consequences of Homogeneous and Heterogeneous Duplications. PLoS Biol 2016; 14:e2000618. [PMID: 27918584 PMCID: PMC5137868 DOI: 10.1371/journal.pbio.2000618] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 11/04/2016] [Indexed: 12/21/2022] Open
Abstract
Gene copy-number variations are widespread in natural populations, but investigating their phenotypic consequences requires contemporary duplications under selection. Such duplications have been found at the ace-1 locus (encoding the organophosphate and carbamate insecticides' target) in the mosquito Anopheles gambiae (the major malaria vector); recent studies have revealed their intriguing complexity, consistent with the involvement of various numbers and types (susceptible or resistant to insecticide) of copies. We used an integrative approach, from genome to phenotype level, to investigate the influence of duplication architecture and gene-dosage on mosquito fitness. We found that both heterogeneous (i.e., one susceptible and one resistant ace-1 copy) and homogeneous (i.e., identical resistant copies) duplications segregated in field populations. The number of copies in homogeneous duplications was variable and positively correlated with acetylcholinesterase activity and resistance level. Determining the genomic structure of the duplicated region revealed that, in both types of duplication, ace-1 and 11 other genes formed tandem 203kb amplicons. We developed a diagnostic test for duplications, which showed that ace-1 was amplified in all 173 resistant mosquitoes analyzed (field-collected in several African countries), in heterogeneous or homogeneous duplications. Each type was associated with different fitness trade-offs: heterogeneous duplications conferred an intermediate phenotype (lower resistance and fitness costs), whereas homogeneous duplications tended to increase both resistance and fitness cost, in a complex manner. The type of duplication selected seemed thus to depend on the intensity and distribution of selection pressures. This versatility of trade-offs available through gene duplication highlights the importance of large mutation events in adaptation to environmental variation. This impressive adaptability could have a major impact on vector control in Africa.
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Affiliation(s)
- Benoît S. Assogba
- Institut des Sciences de l'Evolution de Montpellier (UMR 5554, CNRS-UM-IRD-EPHE), Université de Montpellier, Place Eugène Bataillon, Montpellier, France
- Institut Régional de Santé Publique, Université d’Abomey Calavi, Cotonou, Benin
- Faculté des Sciences et Techniques, Laboratoire de Biologie et de Typage Moléculaire en Microbiologie, Université d’Abomey Calavi, Cotonou, Bénin
| | - Pascal Milesi
- Institut des Sciences de l'Evolution de Montpellier (UMR 5554, CNRS-UM-IRD-EPHE), Université de Montpellier, Place Eugène Bataillon, Montpellier, France
| | - Luc S. Djogbénou
- Institut Régional de Santé Publique, Université d’Abomey Calavi, Cotonou, Benin
| | - Arnaud Berthomieu
- Institut des Sciences de l'Evolution de Montpellier (UMR 5554, CNRS-UM-IRD-EPHE), Université de Montpellier, Place Eugène Bataillon, Montpellier, France
| | - Patrick Makoundou
- Institut des Sciences de l'Evolution de Montpellier (UMR 5554, CNRS-UM-IRD-EPHE), Université de Montpellier, Place Eugène Bataillon, Montpellier, France
| | - Lamine S. Baba-Moussa
- Faculté des Sciences et Techniques, Laboratoire de Biologie et de Typage Moléculaire en Microbiologie, Université d’Abomey Calavi, Cotonou, Bénin
| | - Anna-Sophie Fiston-Lavier
- Institut des Sciences de l'Evolution de Montpellier (UMR 5554, CNRS-UM-IRD-EPHE), Université de Montpellier, Place Eugène Bataillon, Montpellier, France
| | - Khalid Belkhir
- Institut des Sciences de l'Evolution de Montpellier (UMR 5554, CNRS-UM-IRD-EPHE), Université de Montpellier, Place Eugène Bataillon, Montpellier, France
| | - Pierrick Labbé
- Institut des Sciences de l'Evolution de Montpellier (UMR 5554, CNRS-UM-IRD-EPHE), Université de Montpellier, Place Eugène Bataillon, Montpellier, France
| | - Mylène Weill
- Institut des Sciences de l'Evolution de Montpellier (UMR 5554, CNRS-UM-IRD-EPHE), Université de Montpellier, Place Eugène Bataillon, Montpellier, France
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5
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Alout H, Labbé P, Berthomieu A, Makoundou P, Fort P, Pasteur N, Weill M. High chlorpyrifos resistance in Culex pipiens mosquitoes: strong synergy between resistance genes. Heredity (Edinb) 2016; 116:224-31. [PMID: 26463842 PMCID: PMC4806891 DOI: 10.1038/hdy.2015.92] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 06/19/2015] [Accepted: 08/18/2015] [Indexed: 02/08/2023] Open
Abstract
We investigated the genetic determinism of high chlorpyrifos resistance (HCR), a phenotype first described in 1999 in Culex pipiens mosquitoes surviving chlorpyrifos doses ⩾1 mg l(-1) and more recently found in field samples from Tunisia, Israel or Indian Ocean islands. Through chlorpyrifos selection, we selected several HCR strains that displayed over 10 000-fold resistance. All strains were homozygous for resistant alleles at two main loci: the ace-1 gene, with the resistant ace-1(R) allele expressing the insensitive G119S acetylcholinesterase, and a resistant allele of an unknown gene (named T) linked to the sex and ace-2 genes. We constructed a strain carrying only the T-resistant allele and studied its resistance characteristics. By crossing this strain with strains harboring different alleles at the ace-1 locus, we showed that the resistant ace-1(R) and the T alleles act in strong synergy, as they elicited a resistance 100 times higher than expected from a simple multiplicative effect. This effect was specific to chlorpyrifos and parathion and was not affected by synergists. We also examined how HCR was expressed in strains carrying other ace-1-resistant alleles, such as ace-1(V) or the duplicated ace-1(D) allele, currently spreading worldwide. We identified two major parameters that influenced the level of resistance: the number and the nature of the ace-1-resistant alleles and the number of T alleles. Our data fit a model that predicts that the T allele acts by decreasing chlorpyrifos concentration in the compartment targeted in insects.
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Affiliation(s)
- H Alout
- CNRS, IRD, ISEM–UMR, Montpellier, France
- University of Montpellier, Montpellier, France
- Arthropod-Borne and Infectious Diseases Laboratory, Colorado State University, Fort Collins, CO, USA
| | - P Labbé
- CNRS, IRD, ISEM–UMR, Montpellier, France
- University of Montpellier, Montpellier, France
| | - A Berthomieu
- CNRS, IRD, ISEM–UMR, Montpellier, France
- University of Montpellier, Montpellier, France
| | - P Makoundou
- CNRS, IRD, ISEM–UMR, Montpellier, France
- University of Montpellier, Montpellier, France
| | - P Fort
- University of Montpellier, Montpellier, France
- CNRS, CRBM–UMR, Montpellier, France
| | - N Pasteur
- CNRS, IRD, ISEM–UMR, Montpellier, France
- University of Montpellier, Montpellier, France
| | - M Weill
- CNRS, IRD, ISEM–UMR, Montpellier, France
- University of Montpellier, Montpellier, France
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6
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Duron O, Schneppat UE, Berthomieu A, Goodman SM, Droz B, Paupy C, Nkoghe JO, Rahola N, Tortosa P. Origin, acquisition and diversification of heritable bacterial endosymbionts in louse flies and bat flies. Mol Ecol 2014; 23:2105-17. [PMID: 24612422 DOI: 10.1111/mec.12704] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Revised: 02/10/2014] [Accepted: 02/12/2014] [Indexed: 01/08/2023]
Abstract
The γ-proteobacterium Arsenophonus and its close relatives (Arsenophonus and like organisms, ALOs) are emerging as a novel clade of endosymbionts, which are exceptionally widespread in insects. The biology of ALOs is, however, in most cases entirely unknown, and it is unclear how these endosymbionts spread across insect populations. Here, we investigate this aspect through the examination of the presence, the diversity and the evolutionary history of ALOs in 25 related species of blood-feeding flies: tsetse flies (Glossinidae), louse flies (Hippoboscidae) and bat flies (Nycteribiidae and Streblidae). While these endosymbionts were not found in tsetse flies, we identify louse flies and bat flies as harbouring the highest diversity of ALO strains reported to date, including a novel ALO clade, as well as Arsenophonus and the recently described Candidatus Aschnera chinzeii. We further show that the origin of ALO endosymbioses extends deep into the evolutionary past of louse flies and bat flies, and that it probably played a major role in the ecological specialization of their hosts. The evolutionary history of ALOs is notably complex and was shaped by both vertical transmission and horizontal transfers with frequent host turnover and apparent symbiont replacement in host lineages. In particular, ALOs have evolved repeatedly and independently close relationships with diverse groups of louse flies and bat flies, as well as phylogenetically more distant insect families, suggesting that ALO endosymbioses are exceptionally dynamic systems.
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Affiliation(s)
- Olivier Duron
- Laboratoire MIVEGEC, UMR 5290-224 CNRS-IRD-UM1-UM2, Centre de Recherche IRD, 34090, Montpellier, France
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Zélé F, Nicot A, Berthomieu A, Weill M, Duron O, Rivero A. Wolbachia increases susceptibility to Plasmodium infection in a natural system. Proc Biol Sci 2014; 281:20132837. [PMID: 24500167 DOI: 10.1098/rspb.2013.2837] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Current views about the impact of Wolbachia on Plasmodium infections are almost entirely based on data regarding artificially transfected mosquitoes. This work has shown that Wolbachia reduces the intensity of Plasmodium infections in mosquitoes, raising the exciting possibility of using Wolbachia to control or limit the spread of malaria. Whether natural Wolbachia infections have the same parasite-inhibiting properties is not yet clear. Wolbachia-mosquito combinations with a long evolutionary history are, however, key for understanding what may happen with Wolbachia-transfected mosquitoes after several generations of coevolution. We investigate this issue using an entirely natural mosquito-Wolbachia-Plasmodium combination. In contrast to most previous studies, which have been centred on the quantification of the midgut stages of Plasmodium, we obtain a measurement of parasitaemia that relates directly to transmission by following infections to the salivary gland stages. We show that Wolbachia increases the susceptibility of Culex pipiens mosquitoes to Plasmodium relictum, significantly increasing the prevalence of salivary gland stage infections. This effect is independent of the density of Wolbachia in the mosquito. These results suggest that naturally Wolbachia-infected mosquitoes may, in fact, be better vectors of malaria than Wolbachia-free ones.
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Affiliation(s)
- F Zélé
- Maladies Infectieuses et Vecteurs: Ecologie, Génétique, Evolution et Contrôle, CNRS (UMR CNRS-UM1-UM2 5290, IRD 224), Centre de Recherche IRD, 911 Avenue Agropolis, Montpellier 34394, France, Institut des Sciences de l'Evolution, CNRS (UMR 5554), Université de Montpellier II, , Montpellier 34095, France, Centre d'Ecologie Fonctionnelle et Evolutive, CNRS (UMR 5175), 1919 Route de Mende, Montpellier 34293, France
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8
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Fort P, Albertini A, Van-Hua A, Berthomieu A, Roche S, Delsuc F, Pasteur N, Capy P, Gaudin Y, Weill M. Fossil rhabdoviral sequences integrated into arthropod genomes: ontogeny, evolution, and potential functionality. Mol Biol Evol 2011; 29:381-90. [PMID: 21917725 DOI: 10.1093/molbev/msr226] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Retroelements represent a considerable fraction of many eukaryotic genomes and are considered major drives for adaptive genetic innovations. Recent discoveries showed that despite not normally using DNA intermediates like retroviruses do, Mononegaviruses (i.e., viruses with nonsegmented, negative-sense RNA genomes) can integrate gene fragments into the genomes of their hosts. This was shown for Bornaviridae and Filoviridae, the sequences of which have been found integrated into the germ line cells of many vertebrate hosts. Here, we show that Rhabdoviridae sequences, the major Mononegavirales family, have integrated only into the genomes of arthropod species. We identified 185 integrated rhabdoviral elements (IREs) coding for nucleoproteins, glycoproteins, or RNA-dependent RNA polymerases; they were mostly found in the genomes of the mosquito Aedes aegypti and the blacklegged tick Ixodes scapularis. Phylogenetic analyses showed that most IREs in A. aegypti derived from multiple independent integration events. Since RNA viruses are submitted to much higher substitution rates as compared with their hosts, IREs thus represent fossil traces of the diversity of extinct Rhabdoviruses. Furthermore, analyses of orthologous IREs in A. aegypti field mosquitoes sampled worldwide identified an integrated polymerase IRE fragment that appeared under purifying selection within several million years, which supports a functional role in the host's biology. These results show that A. aegypti was subjected to repeated Rhabdovirus infectious episodes during its evolution history, which led to the accumulation of many integrated sequences. They also suggest that like retroviruses, integrated rhabdoviral sequences may participate actively in the evolution of their hosts.
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Affiliation(s)
- Philippe Fort
- Centre de Recherche de Biochimie Macromoléculaire, UMR 5237, CNRS, Universités Montpellier 2 et 1, Montpellier, France.
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9
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Tantely ML, Tortosa P, Alout H, Berticat C, Berthomieu A, Rutee A, Dehecq JS, Makoundou P, Labbé P, Pasteur N, Weill M. Insecticide resistance in Culex pipiens quinquefasciatus and Aedes albopictus mosquitoes from La Réunion Island. Insect Biochem Mol Biol 2010; 40:317-324. [PMID: 20188834 DOI: 10.1016/j.ibmb.2010.02.005] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2009] [Revised: 02/16/2010] [Accepted: 02/18/2010] [Indexed: 05/28/2023]
Abstract
Resistance to insecticides was monitored on Culex pipiens quinquefasciatus mosquitoes collected in twelve localities of La Réunion, a geographically isolated island of the Indian Ocean. This mosquito is of medical concern in the region as a known vector for filariasis and a potential vector for West Nile and Rift Valley Fever viruses. Our bioassays indicated the presence of resistance to all tested insecticides, i.e. organochlorides, organophosphates and pyrethroids. A molecular investigation revealed a higher frequency of resistance genes in the coastal areas compared to elevated rural sites, probably reflecting the different nature of insecticide pressures together with the genetic cost of resistance alleles. A simple molecular test was developed to detect Rdl allele, encoding a gamma-aminobutyric acid (GABA) receptor resistant to dieldrin. Unexpectedly high Rdl frequencies were recorded over the whole island, despite this insecticide having been banned for over 15 years. This resistant allele was also detected for the first time in two samples of Aedes albopictus, a species recently involved in severe Chikungunya epidemics on the island. Rdl selection in these two mosquito species discloses current insecticide pressures in urban areas, from unknown origins, that should be taken into account to develop vector control strategies.
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Affiliation(s)
- Michaël Luciano Tantely
- Université Montpellier 2, UMR CNRS 5554, Institut des Sciences de l'Evolution, Génétique de l'Adaptation, Place Eugène Bataillon, Montpellier 05, France
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Alout H, Labbé P, Berthomieu A, Pasteur N, Weill M. Multiple duplications of the rare ace-1 mutation F290V in Culex pipiens natural populations. Insect Biochem Mol Biol 2009; 39:884-891. [PMID: 19874892 DOI: 10.1016/j.ibmb.2009.10.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2009] [Revised: 10/20/2009] [Accepted: 10/21/2009] [Indexed: 05/28/2023]
Abstract
Two amino acid substitutions in acetylcholinesterase 1 (AChE1), G119S and F290V, are responsible for resistance to organophosphate and carbamate insecticides in Culex pipiens mosquitoes. These mutations generate very different levels of insensitivity to insecticide inhibitors. We described here a biochemical method that rapidly identifies AChE1 variants (susceptible, G119S and F290V, named S, R and V, respectively) present in individual mosquitoes. We investigated the frequency of AChE1 phenotypes in 41 field samples collected around the Mediterranean Sea. F290V substitution was found only in 15 samples and at low frequency, whereas G119S was highly spread in all samples. However, seven V distinct alleles were identified whereas only one R allele was present. The [V] enzymatic phenotype was never observed alone, and the V allele was always found associated with the susceptible and/or G119S AChE1 ([VS], [VR] or [VRS] phenotypes). Furthermore, we showed the presence of duplicated alleles, associating a susceptible and a V copy of the ace-1 gene, in most individuals analyzed for its presence. Evolutionary forces driving the large number of F290V ace-1 alleles and their low frequency in Mediterranean countries are discussed.
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Affiliation(s)
- Haoués Alout
- Team Genomic of Adaptation, CNRS UMR 5554, Institut des Sciences de l'Evolution, c.c.065, Université Montpellier 2, Place E. Bataillon, 34095 Montpellier, France.
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11
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Ben Cheikh R, Berticat C, Berthomieu A, Pasteur N, Ben Cheikh H, Weill M. Genes conferring resistance to organophosphorus insecticides in Culex pipiens (Diptera: Culicidae) from Tunisia. J Med Entomol 2009; 46:523-530. [PMID: 19496423 DOI: 10.1603/033.046.0317] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In Tunisia, the mosquito Culex pipiens shows various organophosphate resistance alleles at Ester and ace-1 loci. The characterization and the distribution pattern of these alleles were studied among 20 populations sampled from north to center of Tunisia. At the Ester locus, Ester4, Ester5, and Ester(B12) were present. A new esterase characterized by the same electrophoretic migration as esterase A1 was identified: A13, encoded by Ester(A13) allele. At the ace-1 locus, the presence of the ace-1(R), ace-1(D), and F290V mutated alleles was also detected. A large heterogeneity in allelic frequencies at Ester and ace-1 loci was observed among samples, with a high significant genotypic differentiation considering both loci (F, = 0.077, P < 10(-5)), depicting variations of insecticide treatment intensity between areas. A comparison between populations collected in 1996 and 2005 showed an absence of significant resistance evolution. However, the high frequencies of resistance alleles in 2005 populations suggested that the selection pressures are still important in Tunisia. Strategies for resistance management are discussed in the context of the current knowledge of the Tunisian situation.
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Affiliation(s)
- Raja Ben Cheikh
- Université Montpellier 2, Place Eugéne Bataillon, 34095 Montpellier cedex 05, France
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Labbé P, Berticat C, Berthomieu A, Unal S, Bernard C, Weill M, Lenormand T. Forty years of erratic insecticide resistance evolution in the mosquito Culex pipiens. PLoS Genet 2008; 3:e205. [PMID: 18020711 PMCID: PMC2077897 DOI: 10.1371/journal.pgen.0030205] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2007] [Accepted: 10/03/2007] [Indexed: 11/26/2022] Open
Abstract
One view of adaptation is that it proceeds by the slow and steady accumulation of beneficial mutations with small effects. It is difficult to test this model, since in most cases the genetic basis of adaptation can only be studied a posteriori with traits that have evolved for a long period of time through an unknown sequence of steps. In this paper, we show how ace-1, a gene involved in resistance to organophosphorous insecticide in the mosquito Culex pipiens, has evolved during 40 years of an insecticide control program. Initially, a major resistance allele with strong deleterious side effects spread through the population. Later, a duplication combining a susceptible and a resistance ace-1 allele began to spread but did not replace the original resistance allele, as it is sublethal when homozygous. Last, a second duplication, (also sublethal when homozygous) began to spread because heterozygotes for the two duplications do not exhibit deleterious pleiotropic effects. Double overdominance now maintains these four alleles across treated and nontreated areas. Thus, ace-1 evolution does not proceed via the steady accumulation of beneficial mutations. Instead, resistance evolution has been an erratic combination of mutation, positive selection, and the rearrangement of existing variation leading to complex genetic architecture. Adaptation is not always a straightforward process, and often results from natural selection tinkering with available variation. We present in this study just such a tortuous natural selection pathway, which allows the mosquito Culex pipiens to resist organophosphorous insecticides. In the Montpellier area, following the use of insecticide to control mosquito populations, a high-resistance allele of the insecticide target enzyme appeared. But this allele also displayed strong deleterious side effects. Recently, several duplicated haplotypes began to spread in natural population that put in tandem a susceptible and a resistant allele. We show that the duplicated haplotypes actually display reduced side effects compared to the resistant allele when in the heterozygous state, but also new and strong costs in the homozygote. This pattern leads to an unexpected equilibrium between four different alleles across treated and nontreated areas. The story of resistance in C. pipiens is indeed far from a slow progression toward a “perfect” adaptation. Rather, selection for resistance to insecticide is a long process of trial and error leading to an uncommon genetic architecture.
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Affiliation(s)
- Pierrick Labbé
- Equipe Génétique de l'Adaptation, Institut des Sciences de l'Evolution, CNRS Université Montpellier 2, Montpellier, France.
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Djogbénou L, Chandre F, Berthomieu A, Dabiré R, Koffi A, Alout H, Weill M. Evidence of introgression of the ace-1(R) mutation and of the ace-1 duplication in West African Anopheles gambiae s. s. PLoS One 2008; 3:e2172. [PMID: 18478097 PMCID: PMC2377098 DOI: 10.1371/journal.pone.0002172] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2007] [Accepted: 04/01/2008] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The role of inter-specific hybridisation is of particular importance in mosquito disease vectors for predicting the evolution of insecticide resistance. Two molecular forms of Anopheles gambiae s.s., currently recognized as S and M taxa, are considered to be incipient sibling species. Hybrid scarcity in the field was suggested that differentiation of M and S taxa is maintained by limited or absent gene flow. However, recent studies have revealed shared polymorphisms within the M and S forms, and a better understanding of the occurrence of gene flow is needed. One such shared polymorphism is the G119S mutation in the ace-1 gene (which is responsible for insecticide resistance); this mutation has been described in both the M and S forms of A. gambiae s.s. METHODS AND RESULTS To establish whether the G119S mutation has arisen independently in each form or by genetic introgression, we analysed coding and non-coding sequences of ace-1 alleles in M and S mosquitoes from representative field populations. Our data revealed many polymorphic sites shared by S and M forms, but no diversity was associated with the G119S mutation. These results indicate that the G119S mutation was a unique event and that genetic introgression explains the observed distribution of the G119S mutation within the two forms. However, it was impossible to determine from our data whether the mutation occurred first in the S form or in the M form. Unexpectedly, sequence analysis of some resistant individuals revealed a duplication of the ace-1 gene that was observed in both A. gambiae s.s. M and S forms. Again, the distribution of this duplication in the two forms most likely occurred through introgression. CONCLUSIONS These results highlight the need for more research to understand the forces driving the evolution of insecticide resistance in malaria vectors and to regularly monitor resistance in mosquito populations of Africa.
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Affiliation(s)
- Luc Djogbénou
- Institut de Recherche pour le Développement, Cotonou, Benin
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou, Benin
| | | | - Arnaud Berthomieu
- Université Montpellier 2, Montpellier, France
- CNRS, Institut des Sciences de l'Evolution, Equipe Génétique de l'Adaptation, Montpellier, France
| | - Roch Dabiré
- Institut Régional des Sciences de Santé, Laboratoire d'Entomologie et de Parasitologie, Bobo-Dioulasso, Burkina Faso
| | - Alphonsine Koffi
- Institut Pierre Richet (IPR)/Institut National de Santé Publique, Abidjan, Côte d̀Ivoire
| | - Haoues Alout
- Université Montpellier 2, Montpellier, France
- CNRS, Institut des Sciences de l'Evolution, Equipe Génétique de l'Adaptation, Montpellier, France
| | - Mylène Weill
- Université Montpellier 2, Montpellier, France
- CNRS, Institut des Sciences de l'Evolution, Equipe Génétique de l'Adaptation, Montpellier, France
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Ben Cheikh R, Berticat C, Berthomieu A, Pasteur N, Ben Cheikh H, Weill M. Characterization of a novel high-activity esterase in Tunisian populations of the mosquito Culex pipiens. J Econ Entomol 2008; 101:484-491. [PMID: 18459415 DOI: 10.1603/0022-0493(2008)101[484:coanhe]2.0.co;2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
AIn the mosquito Culex pipiens (L.) (Diptera: Culicidae) esterases contribute to insecticide resistance by their increased activity. These esterases display a heterogeneous geographical distribution, particularly in Tunisia, where they are very diverse. In this study, we extended the characterization of a highly active esterase first detected in 1996: B12. Esterase B12 displayed the fastest electrophoretic mobility of all the previously described highly active esterases. We showed that it was encoded by the Ester(B12) allele at the Ester locus, and we isolated a strain, TunB12, homozygous for this allele. TunB12 displayed a low (approximately two- to three-fold) but significant resistance to the organophosphates temephos and chlorpyrifos, and to the pyrethroid permethrin. Only temephos resistance was synergized by S,S,S-tributyl-phosphorotrithioate. Real-time quantitative polymerase chain reaction revealed that the Ester(B12) allele was not amplified in TunB12 strain, indicating that B12 high activity could be due to a gene up-regulation mechanism. Ester(B12) allele frequencies also were estimated in 20 Tunisian populations collected in 2005. Analyses revealed a large distribution of this allele all over the country. Finally, sequences of Ester(B12) were acquired and genetic distance trees were constructed with the resistance Ester alleles already published, providing indications about allele's origins. The diverse array of highly active esterases in C. pipiens from Tunisia and the possible scenario of the origin of their coding alleles are discussed in the context of their possible evolution.
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Affiliation(s)
- Raja Ben Cheikh
- Institut des Sciences de l'Evolution (UM2, CNRS), Equipe Génétique de l'Adaptation, Université Montpellier 2 (C.C. 065), 34095 Montpellier, France
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Cui F, Weill M, Berthomieu A, Raymond M, Qiao CL. Characterization of novel esterases in insecticide-resistant mosquitoes. Insect Biochem Mol Biol 2007; 37:1131-1137. [PMID: 17916499 DOI: 10.1016/j.ibmb.2007.07.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2007] [Revised: 06/28/2007] [Accepted: 07/02/2007] [Indexed: 05/25/2023]
Abstract
In the mosquito Culex pipiens complex (Diptera: Culicidae), the amplification of carboxylesterase genes is an important mechanism providing resistance to organophosphate insecticides. Various amplified alleles at the Ester locus have been identified over the world. In this study, two newly detected Ester alleles, Ester(B10) and Ester(11) (including associated Ester(A11) and Ester(B11)), coding for esterases B10 and A11-B11, respectively, are characterized qualitatively and quantitatively. A high molecular identity is observed both at the nucleotide level and at the deduced amino acid level among the known Ester alleles. Real-time quantitative PCR results suggest 2.5-fold amplification of the Ester(B10) allele, 36.5-fold amplification of the Ester(A11) allele, and 19.1-fold amplification of the Ester(B11) allele. The ca. 2-fold difference in amplification level between Ester(A11) and Ester(B11) may indicate a new model for the esterase amplification. Bioassays show that these two resistant Ester alleles only can confer moderate or low resistance to the tested organophosphate insecticides.
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Affiliation(s)
- Feng Cui
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100080, China
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Alout H, Berthomieu A, Cui F, Tan Y, Berticat C, Qiao C, Weill M. Different amino-acid substitutions confer insecticide resistance through acetylcholinesterase 1 insensitivity in Culex vishnui and Culex tritaeniorhynchus (Diptera: Culicidae) from China. J Med Entomol 2007; 44:463-9. [PMID: 17547232 DOI: 10.1603/0022-2585(2007)44[463:dascir]2.0.co;2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Insecticide resistance owing to insensitive acetylcholinesterase (AChE)1 has been reported in several mosquito species, and only two mutations in the ace-1 gene have been implicated in resistance: 119S and 331W substitutions. We analyzed the AChE1 resistance status of Culex vishnui (Theobald) and Culex tritaeniorhynchus Giles sampled in various regions of China. These two species displayed distinct mutations leading to AChE1 insensitivity; the 119S substitution in resistant C. vishnui mosquitoes and the 331W substitution in resistant C. tritaeniorhynchus. A biochemical test was validated to detect the 331W mutation in field samples. The comparison of the recombinant G119S and 331W mutant proteins produced in vitro with the AChE1 extracted from resistant mosquitoes indicated that the AChE1 insensitivity observed could be specifically attributed to these substitutions. Comparison of their biochemical characteristics indicated that the resistance conferred by these mutations depends on the insecticide used, regardless of its class. This resistance seemed to be fixed in the Cx. tritaeniorhynchus populations sampled in a 2000-km transect, suggesting a very high level of insecticide application or a low fitness cost associated with this 331W mutation.
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Affiliation(s)
- Haoues Alout
- Team Genetics of Adaptation, Laboratoire Génétique et Environnement, Institut des Sciences de l'Evolution (UMR CNRS 5554), Université de Montpellier II (C.C. 065), F-34095 Montpellier, France
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Duron O, Boureux A, Echaubard P, Berthomieu A, Berticat C, Fort P, Weill M. Variability and expression of ankyrin domain genes in Wolbachia variants infecting the mosquito Culex pipiens. J Bacteriol 2007; 189:4442-8. [PMID: 17449622 PMCID: PMC1913362 DOI: 10.1128/jb.00142-07] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Wolbachia strains are maternally inherited endosymbiotic bacteria that infect many arthropod species and have evolved several different ways of manipulating their hosts, the most frequent way being cytoplasmic incompatibility (CI). CI leads to embryo death in crosses between infected males and uninfected females as well as in crosses between individuals infected by incompatible Wolbachia strains. The mosquito Culex pipiens exhibits the highest crossing type variability reported so far. Our crossing data support the notion that CI might be driven by at least two distinct genetic units that control the CI functions independently in males and females. Although the molecular basis of CI remains unknown, proteins with ankyrin (ANK) domains represent promising candidates since they might interact with a wide range of host proteins. Here we searched for sequence variability in the 58 ANK genes carried in the genomes of Wolbachia variants infecting Culex pipiens. Only five ANK genes were polymorphic in the genomes of incompatible Wolbachia variants, and none correlated with the CI pattern obtained with 15 mosquito strains (representing 14 Wolbachia variants). Further analysis of ANK gene expression evidenced host- and sex-dependent variations, which did not improve the correlation. Taken together, these data do not support the direct implication of ANK genes in CI determinism.
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Affiliation(s)
- Olivier Duron
- Institut des Sciences de l'Evolution (UMR 5554), Université Montpellier II (C.C. 065), F-34095 Montpellier cedex 05, France
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Labbé P, Berthomieu A, Berticat C, Alout H, Raymond M, Lenormand T, Weill M. Independent Duplications of the Acetylcholinesterase Gene Conferring Insecticide Resistance in the Mosquito Culex pipiens. Mol Biol Evol 2007; 24:1056-67. [PMID: 17283366 DOI: 10.1093/molbev/msm025] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Gene duplication is thought to be the main potential source of material for the evolution of new gene functions. Several models have been proposed for the evolution of new functions through duplication, most based on ancient events (Myr). We provide molecular evidence for the occurrence of several (at least 3) independent duplications of the ace-1 locus in the mosquito Culex pipiens, selected in response to insecticide pressure that probably occurred very recently (<40 years ago). This locus encodes the main target of several insecticides, the acetylcholinesterase. The duplications described consist of 2 alleles of ace-1, 1 susceptible and 1 resistant to insecticide, located on the same chromosome. These events were detected in different parts of the world and probably resulted from distinct mechanisms. We propose that duplications were selected because they reduce the fitness cost associated with the resistant ace-1 allele through the generation of persistent, advantageous heterozygosis. The rate of duplication of ace-1 in C. pipiens is probably underestimated, but seems to be rather high.
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Affiliation(s)
- Pierrick Labbé
- Institut des Sciences de l'Evolution (UMR CNRS 5554), University Montpellier II, Montpellier, France
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Alout H, Berthomieu A, Hadjivassilis A, Weill M. A new amino-acid substitution in acetylcholinesterase 1 confers insecticide resistance to Culex pipiens mosquitoes from Cyprus. Insect Biochem Mol Biol 2007; 37:41-7. [PMID: 17175445 DOI: 10.1016/j.ibmb.2006.10.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2006] [Revised: 09/29/2006] [Accepted: 10/02/2006] [Indexed: 05/13/2023]
Abstract
In insects, selection of insecticide-insensitive acetylcholinesterase (AChE) is a very common resistance mechanism. Mosquitoes possess both AChE1 and AChE2 enzymes and insensitivity is conferred by single amino-acid changes located near the active site of the synaptic AChE1. Only two positions have been reported so far to be involved in resistance, suggesting a very high structural constraint of the AChE1 enzyme. In particular, the G119S substitution was selected in several mosquitoes' species and is now largely spread worldwide. Yet, a different type of AChE1 insensitivity was described 10 years ago in a Culex pipiens population collected in Cyprus in 1987 and fixed thereafter as the ACE-R strain. We report here the complete amino-acid sequence of the ACE-R AChE1 and show that resistance is associated with a single Phe-to-Val substitution of residue 290, which also lines the active site. Comparison of AChE1 activities of the recombinant F290V protein and ACE-R mosquito extracts confirmed the causal role of the substitution in insensitivity. Biochemical characteristics of the mutated protein indicated that the resistance level varies with the insecticide used. A molecular diagnosis test was designed to detect this mutation and was used to show that it is still present in Cyprus Island.
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Affiliation(s)
- Haoues Alout
- Laboratoire Génétique et Environnement Institut des Sciences de l'Evolution (UMR CNRS 5554), Université de Montpellier II (C.C. 065), F-34095 Montpellier cedex 05, France
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20
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Huchard E, Martinez M, Alout H, Douzery EJ, Lutfalla G, Berthomieu A, Berticat C, Raymond M, Weill M. Acetylcholinesterase genes within the Diptera: takeover and loss in true flies. Proc Biol Sci 2006; 273:2595-604. [PMID: 17002944 PMCID: PMC1635460 DOI: 10.1098/rspb.2006.3621] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2006] [Accepted: 05/13/2006] [Indexed: 11/12/2022] Open
Abstract
It has recently been reported that the synaptic acetylcholinesterase (AChE) in mosquitoes is encoded by the ace-1 gene, distinct and divergent from the ace-2 gene, which performs this function in Drosophila. This is an unprecedented situation within the Diptera order because both ace genes derive from an old duplication and are present in most insects and arthropods. Nevertheless, Drosophila possesses only the ace-2 gene. Thus, a secondary loss occurred during the evolution of Diptera, implying a vital function switch from one gene (ace-1) to the other (ace-2). We sampled 78 species, representing 50 families (27% of the Dipteran families) spread over all major subdivisions of the Diptera, and looked for ace-1 and ace-2 by systematic PCR screening to determine which taxonomic groups within the Diptera have this gene change. We show that this loss probably extends to all true flies (or Cyclorrhapha), a large monophyletic group of the Diptera. We also show that ace-2 plays a non-detectable role in the synaptic AChE in a lower Diptera species, suggesting that it has non-synaptic functions. A relative molecular evolution rate test showed that the intensity of purifying selection on ace-2 sequences is constant across the Diptera, irrespective of the presence or absence of ace-1, confirming the evolutionary importance of non-synaptic functions for this gene. We discuss the evolutionary scenarios for the takeover of ace-2 and the loss of ace-1, taking into account our limited knowledge of non-synaptic functions of ace genes and some specific adaptations of true flies.
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Affiliation(s)
- Elise Huchard
- Institut des Sciences de l'Evolution (UMR 5554 CNRS), C.C. 065, Université de Montpellier II34095 Montpellier cedex 5, France
| | - Michel Martinez
- INRA, Unité d'Ecologie animale et Zoologie agricole2, place Pierre Viala, 34060 Montpellier Cedex 01, France
| | - Haoues Alout
- Institut des Sciences de l'Evolution (UMR 5554 CNRS), C.C. 065, Université de Montpellier II34095 Montpellier cedex 5, France
| | - Emmanuel J.P Douzery
- Institut des Sciences de l'Evolution (UMR 5554 CNRS), C.C. 065, Université de Montpellier II34095 Montpellier cedex 5, France
| | - Georges Lutfalla
- UMR 5124 CNRS, C.C.86, Université de Montpellier II34095 Montpellier cedex 5, France
| | - Arnaud Berthomieu
- Institut des Sciences de l'Evolution (UMR 5554 CNRS), C.C. 065, Université de Montpellier II34095 Montpellier cedex 5, France
| | - Claire Berticat
- Institut des Sciences de l'Evolution (UMR 5554 CNRS), C.C. 065, Université de Montpellier II34095 Montpellier cedex 5, France
| | - Michel Raymond
- Institut des Sciences de l'Evolution (UMR 5554 CNRS), C.C. 065, Université de Montpellier II34095 Montpellier cedex 5, France
| | - Mylène Weill
- Institut des Sciences de l'Evolution (UMR 5554 CNRS), C.C. 065, Université de Montpellier II34095 Montpellier cedex 5, France
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Cui F, Raymond M, Berthomieu A, Alout H, Weill M, Qiao CL. Recent emergence of insensitive acetylcholinesterase in Chinese populations of the mosquito Culex pipiens (Diptera: Culicidae). J Med Entomol 2006; 43:878-83. [PMID: 17017223 DOI: 10.1603/0022-2585(2006)43[878:reoiai]2.0.co;2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Organophosphate/carbamate target resistance has emerged in Culex pipiens L. (Diptera: Culicidae), the vector of Wuchereria bancrofti and West Nile virus (family Flaviviridae, genus Flavivirus) in China. The insensitive acetylcholinesterase was detected in only one of 20 samples collected on a north-to-south transect. According to previous findings, a unique mutation, G119S in the ace-1 gene, explained this high insensitivity. Phylogenetic analysis indicates that the mutation G119S recently detected in China results from an independent mutation event. The G119S mutation thus occurred at least three times independently within the Cx. pipiens complex, once in the temperate (Cx. p. pipiens) and twice in the tropical form (Cx. p. quinquefasciatus). Bioassays performed with a purified G119S strain indicated that this substitution was associated with high levels of resistance to chlorpyrifos, fenitrothion, malathion, and parathion, but low levels of resistance to dichlorvos, trichlorfon, and fenthion. Hence, it is possible that in China, dichlorvos, trichlorfon, and fenthion will still achieve effective control even in the presence of the G119S mutation.
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Affiliation(s)
- Feng Cui
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Graduate School, Chinese Academy of Sciences, Beijing, China
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Abstract
Wolbachia are maternally inherited endosymbiotic bacteria that infect many arthropod species and may induce cytoplasmic incompatibility (CI), resulting in abortive embryonic development. One Wolbachia host, Culex pipiens complex mosquitoes, displays high levels of variability in both CI crossing types (cytotypes) and DNA markers. We report here an analysis of 14 mosquito strains, containing 13 Wolbachia variants, and with 13 different cytotypes. Cytotypes were Wolbachia-dependent, as antibiotic treatment rendered all strains tested compatible. Cytotype distributions were independent of geographical distance between sampling sites and host subspecies, suggesting that Wolbachia does not promote a reproductive isolation depending on these parameters. Backcross analysis demonstrated a mild restoring effect of the nuclear genome, indicating that CI is mostly cytoplasmically determined for some crosses. No correlation was found between the phenotypic and genotypic variability of 16 WO prophage and transposon markers, except for the WO prophage Gp15 gene, which encodes a protein similar to a bacterial virulence factor. However, Gp15 is partially correlated with CI expression, suggesting that it could be just linked to a CI gene.
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Affiliation(s)
- Olivier Duron
- Team Genetics of Adaptation, Laboratoire Génétique et Environnement, Institut des Sciences de l"Evolution (UMR CNRS 5554), Université de Montpellier II (C.C. 065), F-34095 Montpellier, cedex 05, France
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Maury B, Martinand-Mari C, Chambon JP, Soulé J, Degols G, Sahuquet A, Weill M, Berthomieu A, Fort P, Mangeat P, Baghdiguian S. Fertilization regulates apoptosis of Ciona intestinalis extra-embryonic cells through thyroxine (T4)-dependent NF-κB pathway activation during early embryonic development. Dev Biol 2006; 289:152-65. [PMID: 16313896 DOI: 10.1016/j.ydbio.2005.10.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2005] [Revised: 09/19/2005] [Accepted: 10/17/2005] [Indexed: 11/23/2022]
Abstract
In Ciona intestinalis, the elimination of extra-embryonic test cells during early stage of development is delayed by a fertilization signal. Test cells undergo a caspase-dependent apoptosis event repressed by thyroxine (T4)-activated NF-kappaB. When apoptosis was experimentally blocked, the hatching stage was delayed. The incubation of unfertilized eggs with a 1-h-fertilized egg extract or purified T4 restored apoptosis in test cells at a similar timing than found in fertilized eggs. Ciona expresses specific genes forming a functional IkappaB/NF-kappaB pathway. One, Ci-p65, was transiently induced upon fertilization via T4 and found to exert its anti-apoptotic role in test cells nuclei as well as in a reconstituted cell system. Blocking NF-kappaB activity by dexamethasone-induced overexpression of Ci-IkappaB abrogated the repression of apoptosis in test cells. Overall, the data are consistent for defining a central coupling role of both T4 and NF-kappaB during early embryo development.
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Affiliation(s)
- Benoît Maury
- UMR 5539, Centre National de la Recherche Scientifique, Dynamique Moléculaire des Interactions Membranaires, Case courrier no. 107-Université Montpellier 2, France
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Landy C, M??chin C, Berthomieu A, Bretot G, Coquard A, Grise P, Dieu B. Safety and Efficacy of Intravesical Instillations of Capsaicin in Urology: About One Case. Drug Saf 2006. [DOI: 10.2165/00002018-200629100-00152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Weill M, Berthomieu A, Berticat C, Lutfalla G, Nègre V, Pasteur N, Philips A, Leonetti JP, Fort P, Raymond M. Insecticide resistance: a silent base prediction. Curr Biol 2004; 14:R552-3. [PMID: 15268871 DOI: 10.1016/j.cub.2004.07.008] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Weill M, Malcolm C, Chandre F, Mogensen K, Berthomieu A, Marquine M, Raymond M. The unique mutation in ace-1 giving high insecticide resistance is easily detectable in mosquito vectors. Insect Mol Biol 2004; 13:1-7. [PMID: 14728661 DOI: 10.1111/j.1365-2583.2004.00452.x] [Citation(s) in RCA: 300] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
High insecticide resistance resulting from insensitive acetylcholinesterase (AChE) has emerged in mosquitoes. A single mutation (G119S of the ace-1 gene) explains this high resistance in Culex pipiens and in Anopheles gambiae. In order to provide better documentation of the ace-1 gene and the effect of the G119S mutation, we present a three-dimension structure model of AChE, showing that this unique substitution is localized in the oxyanion hole, explaining the insecticide insensitivity and its interference with the enzyme catalytic functions. As the G119S creates a restriction site, a simple PCR test was devised to detect its presence in both A. gambiae and C. pipiens, two mosquito species belonging to different subfamilies (Culicinae and Anophelinae). It is possibile that this mutation also explains the high resistance found in other mosquitoes, and the present results indicate that the PCR test detects the G119S mutation in the malaria vector A. albimanus. The G119S has thus occurred independently at least four times in mosquitoes and this PCR test is probably of broad applicability within the Culicidae family.
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Affiliation(s)
- M Weill
- Institut des Sciences de l'Evolution (UMR 5554), Laboratoire Génétique et Environnement, Université Montpellier II, Montpellier, France.
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Weill M, Lutfalla G, Mogensen K, Chandre F, Berthomieu A, Berticat C, Pasteur N, Philips A, Fort P, Raymond M. Comparative genomics: Insecticide resistance in mosquito vectors. Nature 2003; 423:136-7. [PMID: 12736674 DOI: 10.1038/423136b] [Citation(s) in RCA: 278] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Mylène Weill
- Institut des Sciences de l'Evolution, UMR 5554, CC 065, Université Montpellier II, 34095 Montpellier, France.
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Annan Z, Kengne P, Berthomieu A, Antonio-Nkondjio C, Rousset F, Fontenille D, Weill M. Isolation and characterization of polymorphic microsatellite markers from the mosquito Anopheles moucheti, malaria vector in Africa. ACTA ACUST UNITED AC 2002. [DOI: 10.1046/j.1471-8286.2003.00347.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Cohuet A, Simard F, Berthomieu A, Raymond M, Fontenille D, Weill M. Isolation and characterization of microsatellite DNA markers in the malaria vector Anopheles funestus. ACTA ACUST UNITED AC 2002. [DOI: 10.1046/j.1471-8286.2002.00290.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Weill M, Fort P, Berthomieu A, Dubois MP, Pasteur N, Raymond M. A novel acetylcholinesterase gene in mosquitoes codes for the insecticide target and is non-homologous to the ace gene in Drosophila. Proc Biol Sci 2002; 269:2007-16. [PMID: 12396499 PMCID: PMC1691131 DOI: 10.1098/rspb.2002.2122] [Citation(s) in RCA: 166] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Acetylcholinesterase (AChE) is the target of two major insecticide families, organophosphates (OPs) and carbamates. AChE insensitivity is a frequent resistance mechanism in insects and responsible mutations in the ace gene were identified in two Diptera, Drosophila melanogaster and Musca domestica. However, for other insects, the ace gene cloned by homology with Drosophila does not code for the insensitive AChE in resistant individuals, indicating the existence of a second ace locus. We identified two AChE loci in the genome of Anopheles gambiae, one (ace-1) being a new locus and the other (ace-2) being homologous to the gene previously described in Drosophila. The gene ace-1 has no obvious homologue in the Drosophila genome and was found in 15 mosquito species investigated. In An. gambiae, ace-1 and ace-2 display 53% similarity at the amino acid level and an overall phylogeny indicates that they probably diverged before the differentiation of insects. Thus, both genes are likely to be present in the majority of insects and the absence of ace-1 in Drosophila is probably due to a secondary loss. In one mosquito (Culex pipiens), ace-1 was found to be tightly linked with insecticide resistance and probably encodes the AChE OP target. These results have important implications for the design of new insecticides, as the target AChE is thus encoded by distinct genes in different insect groups, even within the Diptera: ace-2 in at least the Drosophilidae and Muscidae and ace-1 in at least the Culicidae. Evolutionary scenarios leading to such a peculiar situation are discussed.
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Affiliation(s)
- Mylène Weill
- Institut des Sciences de l'Evolution (UMR 5554), CC 065, Université Montpellier II, F-34095 Montpellier cedex 05, France.
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Abstract
Wolbachia symbionts are responsible for various alterations in host reproduction. The effects of the host genome on endosymbiont levels have often been suggested, but rarely described. Here, we show that Wolbachia density is strongly modified by the presence of insecticide-resistant genes in the common house mosquito, Culex pipiens. The Wolbachia density was estimated using a real-time quantitative PCR assay. Strains harbouring different genes conferring resistance were more infected than a susceptible strain with the same genetic background. We show that this interaction also operates in natural populations. We propose that mosquitoes may control Wolbachia density less efficiently when they carry an insecticide-resistant gene, i.e. when they suffer from a physiological resistance cost.
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Affiliation(s)
- Claire Berticat
- Institut des Sciences de l'Evolution (UMR 5554), Laboratoire Génétique et Environnement, CC 065, Université de Montpellier II, 34095, Montpellier cedex 05, France
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Weill M, Marquine M, Berthomieu A, Dubois MP, Bernard C, Qiao CL, Raymond M. Identification and characterization of novel organophosphate detoxifying esterase alleles in the Guangzhou area of China. J Am Mosq Control Assoc 2001; 17:238-244. [PMID: 11804460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
In the mosquito Culex pipiens, various alleles at the Ester locus provide insecticide resistance. These resistance alleles display a heterogeneous geographical distribution, particularly in China, where they are highly diverse. A new resistance allele, Ester9, coding for the overproduced esterases A9 and B9, is characterized and compared to the known resistant allele Ester8 isolated from the same southern China sample (from Guangzhou). Both alleles provide low but significant resistance to chlorpyrifos (relative synergism ratio [RSR] > 3) and temephos (RSR = 1.4), which is consistent with the low level of gene amplification they display (15 copies for Ester9 and 4 copies for Ester8). The full genomic sequence of the allele coding A8 and A9 is presented, which allowed us to set up a polymerase chain reaction assay to specifically identify these alleles. The peculiar situation in southern China, where numerous resistance alleles coexist, is discussed in comparison with the Mediterranean situation, the only one with a similar diversity of overproduced esterases.
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Affiliation(s)
- M Weill
- Institut des Sciences de l'Evolution (UMR 5554), Laboratoire Génétique et Environnement, Université de Montpellier II (C.C. 065), France
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Bertault G, Rousset F, Fernandez D, Berthomieu A, Hochberg ME, Callot G, Raymond M. Population genetics and dynamics of the black truffle in a man-made truffle field. Heredity (Edinb) 2001; 86:451-8. [PMID: 11520345 DOI: 10.1046/j.1365-2540.2001.00855.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The colonization dynamics of the black truffle in an artificial field were assessed through analyses of microsatellite and RAPD markers. The truffle field was composed of three tree species and mycelial inoculum of three different origins, and was monitored for the first three years of truffle production. We found very low levels of genetic diversity. Isolation by distance was detected only at the between-tree level. This could be interpreted as local colonization around each tree facilitated by the presence of the tree root system. At the larger spatial scale of the European range, the absence of isolation by distance corroborates the hypothesis of an impact of glaciation on genetic variation, followed by rapid postglaciation demographic expansion. In addition, genetic variation of harvested truffles was explained by neither inoculation origin, nor tree species. Our study questions the real impact of man-made inoculation of tree root systems with fungal mycelia.
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Affiliation(s)
- G Bertault
- Institut des Sciences de l'Evolution (UMR 5554), Laboratoire Génétique et Environnement, CC 65, Université Montpellier II, 34095 Montpellier Cedex 5, France
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