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Bruce A. Webb - One of the best experts on this subject based on the ideXlab platform.
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analysis of gene transcription and relative abundance of the cys motif gene family from Campoletis sonorensis ichnovirus csiv and further characterization of the most abundant cys motif protein whv1 6
Insect Molecular Biology, 2013Co-Authors: Torrence A Gill, Bruce A. WebbAbstract:The cys-motif gene family associated with Campoletis sonorensis ichnovirus contains 10 members, WHv1.6, WHv1.0, VHv1.1, VHv1.4, AHv1.0, A'Hv0.8, FHv1.4, LHv2.8, UHv0.8, and UHv0.8a. The results of this study indicated that, within the encapsidated virion, WHv1.6 is the most abundant cys-motif gene, while the combined AHv genes are the least abundant. During parasitization of Heliothis virescens by Campoletis sonorenis, WHv1.6 transcripts were the mostly highly expressed, while the combined UHv genes had the lowest expression. Further proteomic analysis of WHv1.6 showed that it accumulates at high levels in parasitized plasma by 6 h, and is detectable in the haemocytes, fat body, malpighian tubules, nerve cord and epidermis by 2 days after parasitization. Localization experiments led us to conclude that WHv1.6 interacts with the cell membrane along with other organelles within a virus-infected cell and prevents immunocytes from spreading or adhering to a foreign surface. Similarly to VHv1.4 and VHv1.1, WHv1.6 is able to inhibit the translation of haemocyte and Malpighian tubule RNAs. Our results showed that the expression of cys-motif genes during parasitization is related to the gene copy number of each gene within the encapsidated virion and may also be dependent upon cis-regulatory element activity in different target tissues. In addition, WHv1.6 plays a major role in inhibiting the cellular encapsulation response by H. virescens.
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the Campoletis sonorensis ichnovirus vankyrin protein p vank 1 inhibits apoptosis in insect sf9 cells
Insect Molecular Biology, 2009Co-Authors: Angelika Fathgoodin, Jeremy A Kroemer, Bruce A. WebbAbstract:: The Campoletis sonorensis ichnovirus (CsIV) vankyrin genes encode proteins containing truncated ankyrin repeat domains with sequence homology to the inhibitory domains of NF-kappaB transcription factor inhibitors, IkappaBs. The CsIV vankyrin proteins are thought to be involved in the suppression of NF-kappaB activity during immune response and/or developmental events in the parasitized host. Here we report that when P-vank-1 was expressed stably from Sf9 cells, prolonged survival of these cells was observed after baculovirus infection, UV irradiation, and treatment with the apoptosis-inducing chemical camptothecin compared to untransformed Sf9 cells. Furthermore, P-vank-1 inhibited nuclear and internucleosomal degradation and caspase activity after induction of apoptosis in Sf9 cells stably expressing P-vank-1. This is the first report of a polydnavirus protein with anti-apoptotic function.
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quantitative analysis of hemocyte morphological abnormalities associated with Campoletis sonorensis parasitization
Journal of Insect Science, 2004Co-Authors: Matthew W Turnbull, Stacy B Martin, Bruce A. WebbAbstract:Abstract Endoparasitoids of arthropods evoke host cellular immune responses that result in hemocytic encapsulation of the endoparasitoid, unless these responses are disrupted by the parasite. Our interest has focused on mutualistic viruses found in some hymenopteran endoparasitoids that disrupt hemocyte function and prevent encapsulation. Specifically, the Campoletis sonorensis polydnavirus interacts with wasp factors to suppress immunity via expression of intracellular and secreted viral proteins. To study the roles of specific parasitization-associated factors on immunocyte morphology, fluorescence microscopy was used to visualize the actin cytoskeleton in infected and uninfected cells, or after treatment with C. sonorensis ovarian proteins or plasma from infected larvae. The titer and distribution of F- and G-actin were altered in hemocytes from parasitized insects relative to control cells, with plasma from parasitized larvae having an intermediate effect. This suggests that intracellular and secreted...
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effect of a cys motif protein vhv1 4 of Campoletis sonorensis ichnovirus on the translation of lysozyme mrna
Journal of Asia-pacific Entomology, 2003Co-Authors: Bruce A. WebbAbstract:An endoparasitic wasp, Campoletis sonorensis, is associated with a polydnavirus that protects the host wasp from the cellular immune defenses of its lepidopteran hosts. This virus, the Campoletis sonorensis ichnovirus (CsIV), also delays development of the parasitized host by inhibiting the synthesis of several proteins associated with development. VHv1.4, a cysteine-motif protein encoded in the CsIV genome, is expressed in parasitized host tissues and secreted into the plasma. VHv1.4 is abundantly expressed during parasitization, suggesting that it may play a critical role for a successful parasitization of C. sonorensis. This study tests a possibility that VHv1.4 inhibits the expression of an immune-related gene, lysozyme, of Heliothis virescens at the translation level because earlier studies showed that bacterial immune challenge increases lysozyme transcription, but this was not accompanied by a corresponding increase in enzyme activity in parasitized larvae. The lysozyme gene including open reading frame (ORF) plus both 3' and 5' untranslated regions (UTRs) was cloned from the fat body-originated cDNA of H. virescens and transcribed in vitro. The in vitro transcription product (≈ 1 Kb) was translated in vitro using the rabbit reticulocyte lysate system and ≈ 16 kDa lysozyme protein was synthesized. VHv1.4 (2 μM) did not inhibit the translation of the lysozyme mRNA. This study suggests that lysozyme is not the direct target of VHv1.4 action although its activity may be inhibited indirectly by other parasitization factors.
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characterization of Campoletis sonorensis ichnovirus unique segment b and excision locus structure
Journal of Insect Physiology, 2003Co-Authors: Walaikorn Rattanadechakul, Bruce A. WebbAbstract:Abstract Polydnaviruses (PDVs) are segmented, symbiotic, double-stranded DNA viruses that are vertically transmitted as proviruses within the genomes of some parasitoid Hymenoptera. The PDV associated with the ichneumonid wasp Campoletis sonorensis (CsIV) consists of 24 non-redundant DNA segments varying in size from ~6 to 20 kbp. CsIV segment B, one of the smallest genome segments, was sequenced and the excision sites of the proviral segment were characterized. The segment B sequence was 83.2% non-coding with only two open reading frames (ORFs). Some non-coding sequences have similarities to database sequences and were likely pseudogenic, but most were unrelated to known nucleic acid or predicted protein sequences. One ORF, BHv0.9, encodes a member of the rep gene family and was expressed only in parasitized insects while transcription of the other ORF could not be detected. Previously, a third region of the segment was shown to hybridize to 0.6 and 1.2 kb poly A+ RNAs from female wasps during virus replication ( Theilmann and Summers, 1988 ) but this region did not have an identifiable ORF in the determined sequence. In contrast to CsIV segment W, segment B had little repetitive sequence. The segment B proviral integration locus contains a 59 bp direct imperfect repeat. Further analyses of this integration locus demonstrated that segment B was excised from wasp genomic DNA with flanking sequences at the integration site rejoined after segment excision. The segment B ‘excision locus’ retained one of the two copies of the 59 bp repeat sequence with the other repeat present in the excised segment. The data indicate that Ichnovirus segments have distinctive characteristics possibly reflecting functional co-evolution between the wasp and individual types of polydnavirus segments.
Ted C J Turlings - One of the best experts on this subject based on the ideXlab platform.
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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, 2009Co-Authors: Violaine Jourdie, Nadir Alvarez, Ted C J Turlings, Pierre FranckAbstract: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.
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antennal electrophysiological responses of three parasitic wasps to caterpillar induced volatiles from maize zea mays mays cotton gossypium herbaceum and cowpea vigna unguiculata
Journal of Chemical Ecology, 2005Co-Authors: Sandrine Gouinguene, J A Pickett, L J Wadhams, Michael A Birkett, Ted C J TurlingsAbstract:Many parasitic wasps are attracted to volatiles that are released by plants when attacked by potential hosts. The attractiveness of these semiochemicals from damaged plants has been demonstrated in many tritrophic systems, but the physiological mechanisms underlying the insect responses are poorly understood. We recorded the antennal perception by three parasitoids (Cotesia marginiventris, Microplitis rufiventris, and Campoletis sonorensis) to volatiles emitted by maize, cowpea, and cotton plants after attack by the common caterpillar pest Spodoptera littoralis. Gas chromatography-electroantennography (GC-EAG) recordings showed that wasps responded to many, but not all, of the compounds present at the physiologically relevant levels tested. Interestingly, some minor compounds, still unidentified, elicited strong responses from the wasps. These results indicate that wasps are able to detect many odorant compounds released by the plants. It remains to be determined how this information is processed and leads to the specific behavior of the parasitoids.
Howard J. Williams - One of the best experts on this subject based on the ideXlab platform.
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host selection behavior of Campoletis sonorensis a model system
Biological Control, 1991Co-Authors: Bradleigh S Vinson, Howard J. WilliamsAbstract:Abstract Plants play a role in the host selection strategy of Campoletis sonorensis , an ichneumonid parasitoid that attacks the larval stages of a number of plant-feeding lepidoptera. We examine the early host selection behavior of C. sonorensis in response to plants and the herbivores that serve as hosts. We bring together some new data and organize the published information to provide an overview of the host selection behavior of Campoletis . We also compare the results of our studies utilizing C. sonorensis , a generalist, to published data concerning two specialists, Microplitis croceipes , a braconid with the same host system, and Diadromus pulchellus , an ichneumonid specializing in both the plant and the hosts it attacks.
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stimuli influencing host microhabitat location in the parasitoid Campoletis sonorensis
Entomologia Experimentalis Et Applicata, 1991Co-Authors: Heather J. Mcauslane, S B Vinson, Howard J. WilliamsAbstract:The host microhabitat location behavior of females of the generalist parasitoid Campoletis sonorensis (Cameron) (Hymenoptera: Ichneumonidae) was studied in a wind tunnel. Visual cues associated with the host plant cotton, Gossypium hirsutum L., were important and significantly more parasitoids completed flights to a damaged 4-leaf cotton plant bearing a Heliothis virescens (F.) (Lepidoptera: Noctuidae) larva and frass than to a similarly damaged single leaf with frass and a larva. This difference in completed flights was not due to differences in amounts of volatiles released by the two stimuli, Both naive and experienced parasitoids responded differently to an undamaged cotton leaf, a mechanically damaged leaf, a naturally damaged leaf with the host removed and a naturally damaged leaf with a host larva. Parasitoids completed significantly fewer flights to the undamaged sources of volatiles than to damaged sources of volatiles. Experienced females responded strongly to all types of damage. The number of flights completed by naive females to the three types of damage differed but not significantly and was less than the number completed by experienced females. Components of the preflight experience were varied to determine which factors were responsible for the higher response of experienced females to the host/plant complex. Oviposition was the most important component of this experience. Contact with host frass or plant damage followed by oviposition did not increase the response over that exhibited by females allowed oviposition only. When frass or damaged plant material were contacted without subsequent oviposition, females completed fewer flights than naive females.
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Effect of host diet on flight behavior of the parasitoid Campoletis sonorensis (Hymenoptera: Ichneumonidae).
Journal of Entomological Science, 1990Co-Authors: Heather J. Mcauslane, S. Bradleigh Vinson, Howard J. WilliamsAbstract:The effect of larval host diet on the flight behavior and microhabitat preference of the parasitoid, Campoletis sonorensis (Cameron), was studied in a wind tunnel bioassay. Campoletis sonorensis wa...
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influence of host plant on mate location by the parasitoid Campoletis sonorensis hymenoptera ichneumonidae
Environmental Entomology, 1990Co-Authors: Heather J. Mcauslane, S B Vinson, Howard J. WilliamsAbstract:In wind tunnel flight tests, only 13% of male Campoletis sonorensis (Cameron) located a female in the absence of a cotton plant, whereas 63% of males located a female placed on a leaf of a cotton plant. Males flown to plants only in the wind tunnel zigzagged in the plume of the plant volatiles but landed infrequently. The increased mate location observed when females were located on a cotton plant was due partly to plant olfactory cues and partly to plant visual cues. Males located females 60% of the time when females were placed on plants and only 33% of the time when the plant was hidden from the male's view but plant volatiles were present. Male flight behavior is described and was distinctly different toward a female compared with a plant alone.
Bradleigh S Vinson - One of the best experts on this subject based on the ideXlab platform.
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interaction between the larval endoparasitoid Campoletis sonorensis hymenoptera ichneumonidae and its host the tobacco budworm lepidoptera noctuidae
Annals of The Entomological Society of America, 2000Co-Authors: Jing Sheng Hu, Bradleigh S VinsonAbstract:Studies on growth and development of Campoletis sonorensis (Cameron) in various instar Heliothis virescens (F.) larvae were conducted. The behavior and morphological changes of the parasitized host was also evaluated. The results indicate that the host's age at the time of parasitism apparently influenced the development and subsequent fitness of the parasitoid. When initiating development in 3rd or 4th instar hosts, the parasitoid developed significantly slower than when initiating in 1st instar hosts. Furthermore, when developing in 3rd or 4th instar hosts, the parasitoid developed significantly faster during embryonic and 1st instar stages, and significantly slower during the 2nd, 3rd, and 4th instar stages than those developing in 1st instar hosts. In younger hosts, parasitoids also produced a significantly reduced body length, weight, longevity, and egg production estimate. Parasitism of H. virescens larvae by C. sonorensis changed host's morphology and behavior allowing easy identification of parasitized individuals and estimation of the age of the developing parasitoid within its host.
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host selection behavior of Campoletis sonorensis a model system
Biological Control, 1991Co-Authors: Bradleigh S Vinson, Howard J. WilliamsAbstract:Abstract Plants play a role in the host selection strategy of Campoletis sonorensis , an ichneumonid parasitoid that attacks the larval stages of a number of plant-feeding lepidoptera. We examine the early host selection behavior of C. sonorensis in response to plants and the herbivores that serve as hosts. We bring together some new data and organize the published information to provide an overview of the host selection behavior of Campoletis . We also compare the results of our studies utilizing C. sonorensis , a generalist, to published data concerning two specialists, Microplitis croceipes , a braconid with the same host system, and Diadromus pulchellus , an ichneumonid specializing in both the plant and the hosts it attacks.
Christopher J Sanders - One of the best experts on this subject based on the ideXlab platform.
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host plant mediated effects of transgenic maize on the insect parasitoid Campoletis sonorensis hymenoptera ichneumonidae
Biological Control, 2007Co-Authors: Christopher J Sanders, J K Pell, G M Poppy, Alan Raybould, Monica Garciaalonso, T H SchulerAbstract:Determining the impact of genetically modified (GM) crops on beneficial organisms is an important aspect of the environmental risk assessment of GM crops. In the present study, the impact of Bt maize expressing Cry1Ab on the development and behaviour of the parasitoid Campoletis sonorensis was compared to individuals reared on hosts fed conventionally bred plants partially resistant to the European corn borer (Ostrinia nubilalis Hubner) and on susceptible maize hybrids. Adult parasitoids reared on Bt maize-fed Spodoptera frugiperda larvae were significantly smaller (15–30%) than those reared in hosts fed either of the conventional maize hybrids. The magnitude of this effect was dependent on the size of the host at oviposition and its subsequent growth rate. The development time of C. sonorensis was not affected by the maize treatment. In choice tests, female parasitoids displayed no preference for hosts fed a specific maize hybrid. No Cry1Ab was detected within adult parasitoids.
