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Beatrice Lanzrein - One of the best experts on this subject based on the ideXlab platform.

  • the orchestrated manipulation of the host by Chelonus inanitus and its polydnavirus
    Parasitoid Viruses#R##N#Symbionts and Pathogens, 2012
    Co-Authors: Beatrice Lanzrein, Rita Pfisterwilhelm, Martha Kaeslin, Gabriela Wespi, Thomas Roth
    Abstract:

    Publisher Summary This chapter reveals physiological, biochemical, ultrastructural, and molecular methods, and this broad approach clearly shows that the interactions of the Chelonus inanitus bracovirus (CiBV) venom and the parasitoid larva are multifaceted and change in the course of parasitoid and host development. The interactions of the Chelonus inanitus bracovirus (CiBV) and the parasitoid larva with the host are complex and variable and venom is essential only in the initial phase of parasitization. C. inanitus is an egg–larval parasitoid and in the beginning it is a conformer and hardly influences the host. But towards the end of its first larval instar, when the host is a fourth-instar larva, CiBV and the parasitoid larva begin to manipulate the host at various levels in an orchestrated manner. CiBV plays piano pianissimo as only low amounts of viral transcripts and only very few virus-related proteins of low abundance are found in the host. Expression of viral genes varies along with host and parasitoid development. Nevertheless, the effects of CiBV are strong: the virus prevents encapsulation of the parasitoid larva, alters the host's nutritional physiology, and induces a developmental arrest in the prepupal stage by acting on the host's ecdysone production.

  • the venom composition of the parasitic wasp Chelonus inanitus resolved by combined expressed sequence tags analysis and proteomic approach
    BMC Genomics, 2010
    Co-Authors: Bruno Vincent, Beatrice Lanzrein, Martha Kaeslin, Thomas Roth, Manfred Heller, Julie Poulain, Francois Cousserans, Johann Schaller, Marylene Poirie, Jeanmichel Drezen
    Abstract:

    Parasitic wasps constitute one of the largest group of venomous animals. Although some physiological effects of their venoms are well documented, relatively little is known at the molecular level on the protein composition of these secretions. To identify the majority of the venom proteins of the endoparasitoid wasp Chelonus inanitus (Hymenoptera: Braconidae), we have randomly sequenced 2111 expressed sequence tags (ESTs) from a cDNA library of venom gland. In parallel, proteins from pure venom were separated by gel electrophoresis and individually submitted to a nano-LC-MS/MS analysis allowing comparison of peptides and ESTs sequences. About 60% of sequenced ESTs encoded proteins whose presence in venom was attested by mass spectrometry. Most of the remaining ESTs corresponded to gene products likely involved in the transcriptional and translational machinery of venom gland cells. In addition, a small number of transcripts were found to encode proteins that share sequence similarity with well-known venom constituents of social hymenopteran species, such as hyaluronidase-like proteins and an Allergen-5 protein. An overall number of 29 venom proteins could be identified through the combination of ESTs sequencing and proteomic analyses. The most highly redundant set of ESTs encoded a protein that shared sequence similarity with a venom protein of unknown function potentially specific of the Chelonus lineage. Venom components specific to C. inanitus included a C-type lectin domain containing protein, a chemosensory protein-like protein, a protein related to yellow-e3 and ten new proteins which shared no significant sequence similarity with known sequences. In addition, several venom proteins potentially able to interact with chitin were also identified including a chitinase, an imaginal disc growth factor-like protein and two putative mucin-like peritrophins. The use of the combined approaches has allowed to discriminate between cellular and truly venom proteins. The venom of C. inanitus appears as a mixture of conserved venom components and of potentially lineage-specific proteins. These new molecular data enrich our knowledge on parasitoid venoms and more generally, might contribute to a better understanding of the evolution and functional diversity of venom proteins within Hymenoptera.

  • stage dependent strategies of host invasion in the egg larval parasitoid Chelonus inanitus
    Journal of Insect Physiology, 2005
    Co-Authors: Martha Kaeslin, Christa Grossniklausburgin, Toni Wyler, Irene Wehrle, Ursula Guggisberg, Johannes C Schittny, Beatrice Lanzrein
    Abstract:

    Chelonus inanitus (Braconidae) is a solitary egg-larval parasitoid which lays its eggs into eggs of Spodoptera littoralis (Noctuidae); the parasitoid larva then develops in the haemocoel of the host larva. Host embryonic development lasts approx. 3.5 days while parasitoid embryonic development lasts approx. 16 h. All stages of host eggs can be successfully parasitized, and we show here that either the parasitoid larva or the wasp assures that the larva eventually is located in the host's haemocoel. (1) When freshly laid eggs, up to almost 1-day-old, are parasitized, the parasitoid hatches while still in the yolk and enters the host either after waiting or immediately through the dorsal opening. (2) When 1-2-day-old eggs are parasitized, the host embryo has accomplished final dorsal closure and is covered by an embryonic cuticle when the parasitoid hatches; in this case the parasitoid larva bores with its moving abdominal tip into the host. (3) When 2.5-3.5-day-old eggs are parasitized, the wasp oviposits directly into the haemocoel of the host embryo; from day 2 to 2.5 the embryo is still very small and the wasps, after probing, often restrain from oviposition for a few hours.

  • characterization of a 212kd protein released into the host by the larva of the endoparasitoid Chelonus inanitus hymenoptera braconidae
    Journal of Insect Physiology, 2001
    Co-Authors: Anita Hochuli, Beatrice Lanzrein
    Abstract:

    Abstract Previous studies have shown that the larva of Chelonus inanitus plays an essential role in inducing the precocious onset of metamorphosis in polydnavirus/venom-containing Spodoptera littoralis , and that this effect might be due to proteins released by the parasitoid larva into the host. Here we show that a 212 kD protein is the predominant protein released in vitro by late first instar parasitoids. This protein does not accumulate anywhere in the parasitoid body. Polyclonal antibodies specific for the 212 kD protein were produced and immunoblot analyses revealed that this protein begins to be released by parasitoid larvae when the precocious onset of metamorphosis is induced in the host. Amino acid sequences of the N-terminus and of internal fragments of the 212 kD protein were determined and glycoprotein detection showed that this protein is glycosylated. The availability of specific antibodies and the amino acid sequence information should now allow us to clone and express the 212 kD protein and to directly study its functional significance.

  • biology and morphology of the parasitoid Chelonus inanitus braconidae hymenoptera and effects on the development of its host spodoptera littoralis noctuidae lepidoptera
    Invertebrate Reproduction & Development, 1994
    Co-Authors: Christa Grossniklausburgin, Rita Pfisterwilhelm, Toni Wyler, Beatrice Lanzrein
    Abstract:

    Summary The solitary egg-larval parasitoids of the genus Chelonus have the unique effect of inducing in their lepidopterous hosts the precocious onset of metamorphosis and developmental arrest in the precocious prepupa. As a prerequisite to identifying the physiological and biochemical mechanisms underlying these developmental effects, we analyzed the morphology and various growth parameters in the course of development of Chelonus inanitus and studied the effect of this parasitoid on growth and development of its host Spodoptera littoralis. We show the first scanning electron microscopic study of the internal stages of an endoparasitic wasp from the embryo to the third instar. By including observations from microscopic and histological analyses we describe the different stages in the development of the anal vesicle and the formation of new segments and show that the anal vesicle has surface structures which were never described before. We also demonstrate that the head and mouthparts change entirely with...

Violaine Jourdie - One of the best experts on this subject based on the ideXlab platform.

  • Phylogeography of Chelonus insularis (Hymenoptera: Braconidae) and Campoletis sonorensis (Hymenoptera: Ichneumonidae), Two Primary Neotropical Parasitoids of the Fall Armyworm (Lepidoptera: Noctuidae)
    Annals of the Entomological Society of America, 2010
    Co-Authors: Violaine Jourdie, Ted C J Turlings, Henry Murillo, Eduardo Gabriel Virla, José Maurício Simões Bento, Nadir Alvarez
    Abstract:

    In a previous study, we observed no spatial genetic structure in Mexican populations of the parasitoids Chelonus insularis Cresson (Hymenoptera: Braconidae) and Campoletis sonorensis Cameron (Hymenoptera: Ichneumomdae) by using microsatellite markers. In the current study, we investigated whether for these important parasitoids of the fall armyworm (Lepidoptera: Noctuidae) there is any genetic structure at a larger scale. Insects of both species were collected across the American continent and their phylogeography was investigated using both nuclear and mitochondrial markers. Our results suggest an ancient north-south migration of C. insularis, whereas no clear pattern could be determined for C. sonorensis. Nonetheless, the resulting topology indicated the existence of a cryptic taxon within this later species: a few Canadian specimens determined as C. sonorensis branch outside a clade composed of the Argentinean Chelonus grioti Blanchard, the Brazilian Chehnus flavicincta Ashmead, and the rest of the C. sonorensis individuals. The individuals revealing the cryptic taxon were collected from Trichoplusia ni (Hubner) (Lepidoptera: Noctuidae) on tomato (Lycopersicon spp.) and may represent a biotype that has adapted to the early season phenology of its host. Overall, the loosely defined spatial genetic structure previously shown at a local fine scale also was found at the larger scale, for both species. Dispersal of these insects may be partly driven by wind as suggested by genetic similarities between individuals coming from very distant locations.

  • Phylogeography of Chelonus insularis (Hymenoptera: Braconidae) and Campoletis sonorensis (Hymenoptera: Ichneumonidae), Two Primary Neotropical Parasitoids of the Fall Armyworm (Lepidoptera: Noctuidae)
    'Entomological Society of America', 2010
    Co-Authors: Violaine Jourdie, Murillo Henry, Virla, Eduardo Gabriel, Bento, José Mauricio, Turlings, Ted C. J., Alvarez Nadir
    Abstract:

    In a previous study, we observed no spatial genetic structure in Mexican populations of the parasitoids Chelonus insularis Cresson (Hymenoptera: Braconidae) and Campoletis sonorensis Cameron (Hymenoptera: Ichneumonidae) by using microsatellite markers. In the current study, we investigated whether for these important parasitoids of the fall armyworm (Lepidoptera: Noctuidae) there is any genetic structure at a larger scale. Insects of both species were collected across the American continent and their phylogeography was investigated using both nuclear and mitochondrial markers. Our results suggest an ancient north-south migration of C. insularis, whereas no clear pattern could be determined for C. sonorensis. Nonetheless, the resulting topology indicated the existence of a cryptic taxon within this later species: a few Canadian specimens determined as C. sonorensis branch outside a clade composed of the Argentinean Chelonus grioti Blanchard, the Brazilian Chelonus flavicincta Ashmead, and the rest of the C. sonorensis individuals. The individuals revealing the cryptic taxon were collected from Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae) on tomato (Lycopersicon spp.) and may represent a biotype that has adapted to the early season phenology of its host. Overall, the loosely defined spatial genetic structure previously shown at a local fine scale also was found at the larger scale, for both species. Dispersal of these insects may be partly driven by wind as suggested by genetic similarities between individuals coming from very distant locations.Fil: Violaine, Jourdie. Universite de Neuchatel; SuizaFil: Virla, Eduardo Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Murillo, Henry. University of Windsor. Department of Biological Sciences; CanadáFil: Bento, José Mauricio. Universidade de Sao Paulo; BrasilFil: Turlings, Ted C. J.. Universite de Neuchatel; SuizaFil: Alvarez, Nadir. Universite de Neuchatel; Suiz

  • isolation and characterization of polymorphic microsatellite loci in two primary parasitoids of the noctuid spodoptera frugiperda Chelonus insularis and campoletis sonorensis hymenoptera
    Molecular Ecology Resources, 2009
    Co-Authors: Violaine Jourdie, Nadir Alvarez, Ted C J Turlings, Pierre Franck
    Abstract:

    Fifteen and 13 microsatellite loci were isolated, respectively, from Campoletis sonorensis Cameron and from Chelonus insularis Cresson. These two parasitic Hymenoptera are primary parasitoids of Lepidoptera in North, Central and South America, including the important agricultural pest Spodoptera frugiperda. Allelic diversity and heterozygosity were quantified in samples from Mexico. Each locus was polymorphic, with the number of alleles ranging from two to 16 in C. sonorensis and from four to 18 in C. insularis. Heterozygosity ranged from 0.088 to 0.403 in C. sonorensis and from 0.106 to 0.458 in C. insularis.

Pierre Franck - One of the best experts on this subject based on the ideXlab platform.

Nadir Alvarez - One of the best experts on this subject based on the ideXlab platform.

  • Phylogeography of Chelonus insularis (Hymenoptera: Braconidae) and Campoletis sonorensis (Hymenoptera: Ichneumonidae), Two Primary Neotropical Parasitoids of the Fall Armyworm (Lepidoptera: Noctuidae)
    Annals of the Entomological Society of America, 2010
    Co-Authors: Violaine Jourdie, Ted C J Turlings, Henry Murillo, Eduardo Gabriel Virla, José Maurício Simões Bento, Nadir Alvarez
    Abstract:

    In a previous study, we observed no spatial genetic structure in Mexican populations of the parasitoids Chelonus insularis Cresson (Hymenoptera: Braconidae) and Campoletis sonorensis Cameron (Hymenoptera: Ichneumomdae) by using microsatellite markers. In the current study, we investigated whether for these important parasitoids of the fall armyworm (Lepidoptera: Noctuidae) there is any genetic structure at a larger scale. Insects of both species were collected across the American continent and their phylogeography was investigated using both nuclear and mitochondrial markers. Our results suggest an ancient north-south migration of C. insularis, whereas no clear pattern could be determined for C. sonorensis. Nonetheless, the resulting topology indicated the existence of a cryptic taxon within this later species: a few Canadian specimens determined as C. sonorensis branch outside a clade composed of the Argentinean Chelonus grioti Blanchard, the Brazilian Chehnus flavicincta Ashmead, and the rest of the C. sonorensis individuals. The individuals revealing the cryptic taxon were collected from Trichoplusia ni (Hubner) (Lepidoptera: Noctuidae) on tomato (Lycopersicon spp.) and may represent a biotype that has adapted to the early season phenology of its host. Overall, the loosely defined spatial genetic structure previously shown at a local fine scale also was found at the larger scale, for both species. Dispersal of these insects may be partly driven by wind as suggested by genetic similarities between individuals coming from very distant locations.

  • isolation and characterization of polymorphic microsatellite loci in two primary parasitoids of the noctuid spodoptera frugiperda Chelonus insularis and campoletis sonorensis hymenoptera
    Molecular Ecology Resources, 2009
    Co-Authors: Violaine Jourdie, Nadir Alvarez, Ted C J Turlings, Pierre Franck
    Abstract:

    Fifteen and 13 microsatellite loci were isolated, respectively, from Campoletis sonorensis Cameron and from Chelonus insularis Cresson. These two parasitic Hymenoptera are primary parasitoids of Lepidoptera in North, Central and South America, including the important agricultural pest Spodoptera frugiperda. Allelic diversity and heterozygosity were quantified in samples from Mexico. Each locus was polymorphic, with the number of alleles ranging from two to 16 in C. sonorensis and from four to 18 in C. insularis. Heterozygosity ranged from 0.088 to 0.403 in C. sonorensis and from 0.106 to 0.458 in C. insularis.

Ivan Cruz - One of the best experts on this subject based on the ideXlab platform.

  • ocorrencia do parasitoide Chelonus insularis no sul de minas gerais associado a lagartas de spodoptera frugiperda na cultura de milho
    REVISTA BRASILEIRA DE AGROECOLOGIA, 2009
    Co-Authors: Maria De Lourdes Figueiredo, Ivan Cruz, Rafael Braga Da Silva
    Abstract:

    Foi monitorada a ocorrencia de Chelonus insularis Cresson (Hymenoptera: Braconidae), um dos principais parasitoides de Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae), em regioes produtoras de milho do sul do estado de Minas Gerais, Brasil, durante tres anos consecutivos. Apesar de ser um parasitoide que oviposita nos ovos do hospedeiro, ocorre a eclosao da lagarta de S. frugiperda. No entanto, a lagarta parasitada praticamente nao causa danos significativos a planta hospedeira. O parasitoide ocorreu em praticamente todos os anos e municipios amostrados. Parasitismo natural acima de 50% foi observado em alguns dos municipios indicando a importância do agente de controle biologico da praga na cultura do milho.

  • flutuacao populacional de Chelonus insularis cresson hymenoptera braconidae em em millho convencional e milho transgenico
    REVISTA BRASILEIRA DE AGROECOLOGIA, 2009
    Co-Authors: Tamara Esteves Ferreira, Ivan Cruz, Ivana Fernandes Da Silva, Ana Luisa Gangana De Castro, Mauricio Lopes Leao, Cristiane De Souza Paula, Ana Paula De Jesus Menezes
    Abstract:

    Chelonus insularis e um parasitoide de ovos de Spodopetra frugiperda. O inseto e utilizado no manejo de pragas com enfase ao controle biologico que consiste no emprego de insetos beneficos para combater inseto-praga. O experimento foi conduzido na Embrapa Milho e Sorgo, em Sete Lagoas, MG, em area de cultivo convencional, utilizando plantio direto, sem aplicacao alguma de produtos quimicos. Foram comparadas uma cultivar convencional com outra similar, porem, geneticamente transformada contendo o gene da bacteria Bacillus thuringiensis (milho Bt). O numero de lagartas coletadas foi muito maior no milho convencional. No entanto, apos duas semanas este numero se igualou, provavelmente pela atuacao de parasitoides como o C. insularis que foi muito maior na area cultiva com milho convencional.

  • aspectos biologicos do parasitoide Chelonus insularis cresson hymenoptera braconidae criados em ovos de spodoptera frugiperda smith lepidoptera noctuidae
    Revista Brasileira De Zoologia, 1995
    Co-Authors: M A A Rezende, Ivan Cruz, Terezinha M C Della Lucia
    Abstract:

    Biological aspects of Chelonus insularis (Cresson, 1865) an egg-larval parasitoid reared on Spodoptera frugiperda (Smith, 1797) eggs Chelonus insularis (Cresson. 1865) has been cited in the international literature as a promissing biological control agent against the fall armyworm, Spodoptera frugiperda (Smith, 1797). Its field occurrence in Sete Lagoas, Minas Gerais (Brasil) has been increasing in the last years. For these reasons this experiment was conducted in the laboratory, at the National Corn and Sorghum Research Center, of EMBRAPA, under temperature of 25oC. RH of 73% and photophase of 12 hours. Ten couples of the parasitoid were individually placed in a glass jar (5 liters capacity). They were fed on a 10% sugar solution. Each couple received one fall armyworm egg mass to oviposit during a 24-hour period. After hatching, the larvae were fed on artificial bean diet, up to the death caused by the parasitoid larvae. The total biological life cycle was 26.61 days on the average (larval period of 20.42 and pupal period of 6.19 days). The average weight of two days - old pupae was 0.02g. The adult longevity was on average. 10 days (8.4 days for males and 11.6 days for females). The greatest rate of parasitism occurred when the female was three days old, with a maximum of 92 eggs parasitized in that day.

  • comportamento de lagartas de spodopetra frugiperda lepidoptera noctuidae parasitadas por Chelonus insularis hymenoptera braconidae sobre plantas de milho
    1995
    Co-Authors: M A A Rezende, T M C Della Lucia, Ivan Cruz
    Abstract:

    This research was conducted in greenhouse at the National Corn and Sorghum research center of Embrapa in Sete Lagoas, MG, Brasil. It aimed to study the general behavior of Spodoptera frugiperda lervae attacked by the egg-larval parasitoid Chelonus Insularis. Fourteen parasitized and fourteen non-parasitized 3 days old host larvae evaluated using a visual scale form zero to five. On 6th observation day plant corn leaf, regardless of being parasitized. Healthy larvae presented high mobility and caused higher damage on the plants than parasitized larvae which pupate earlier.