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John P Edwards - One of the best experts on this subject based on the ideXlab platform.
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Infection by the microsporidium Vairimorpha necatrix (Microspora: Microsporidia) elevates juvenile hormone titres in larvae of the tomato moth, Lacanobia oleracea (Lepidoptera: Noctuidae).
Journal of Invertebrate Pathology, 2007Co-Authors: Rachel E. Down, John P Edwards, Howard A. Bell, Anne E. Kirkbride-smith, Gareth Bryning, Robert J. WeaverAbstract:The effects of infection by a microsporidium, Vairimorpha necatrix (Kramer), on the endogenous levels of juvenile hormones in tomato moth (Lacanobia oleracea L.) larvae were investigated. Levels of juvenile hormone II (JH II) were 10-fold greater in the infected larvae on day two of the sixth stadium but no significant difference was observed on day seven. Juvenile hormone I (JH I) was also detected in day two and day seven sixth instar infected larvae but was not detected in non-infected larvae. The duration of the fifth and sixth stadia was significantly longer for infected larvae when compared with non-infected larvae. No evidence was found to suggest that supernumerary moults are a feature of infection by V. necatrix in L. oleracea larvae. Experiments were performed to determine whether the elevation in JH levels, which probably prevents pupation, is an adaptive mechanism of the microsporidium for extending the growth phase of the host, thereby allowing increased spore production. A proportion of infected larvae were collected on days 9 and 24 of the sixth stadium and spore extracts prepared from each larva. These days represent the average duration of the sixth stadium required for uninfected larvae to reach pupation, and the average number of days that V. necatrix-infected larvae survive in the sixth stadium before dying from infection. The mean spore yields from infected larvae 24 days into the sixth stadium were significantly higher than the spore yields obtained from day nine sixth instar larvae. The hypothesis that V. necatrix manipulates host endocrinology (i.e. prolong the host larval state to maximise spore yield) is discussed in context with the results obtained.
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The ectoparasitic wasp Eulophus pennicornis (Hymenoptera: Eulophidae) uses instar-specific endocrine disruption strategies to suppress the development of its host Lacanobia oleracea (Lepidoptera: Noctuidae).
Journal of Insect Physiology, 2006Co-Authors: John P Edwards, Neil Audsley, Howard A. Bell, Anne E. Kirkbride-smith, Gareth Bryning, Caroline Frisco, Michel CussonAbstract:Abstract To successfully complete its development, the gregarious ectoparasitoid Eulophus pennicornis must inhibit the moult of its host, Lacanobia oleracea . In the present study, we examined the possibility that moult- and metamorphosis-associated endocrine events may be disrupted in caterpillars parasitized as newly moulted last (sixth) instars. Juvenile hormone (JH) titres on days 2 and 5 of the final stadium were significantly higher (>100 fold) in parasitized than in non-parasitized hosts, in which JH was essentially absent. Elevated JH levels were associated with reduced haemolymph JH esterase (JHE) activity (down by ⩽99.8%) and enhanced in vitro JH biosynthesis by the corpora allata (CA) (up to 4.5 fold). Wasp adults and/or larvae, in which we measured high levels of JH III (up to 2.7 ng/g), but little or no JH I or JH II, were not seen as likely sources of JH in parasitized hosts, in which we found mostly JH I and JH II. In addition, removal of parasitoid eggs or larvae after oviposition did not prevent the rise in JH titres seen in parasitoid-laden hosts, suggesting that wasp venom may be responsible for the observed hormonal dysfunction. Host haemolymph 20-hydroxyecdysone (20-E) levels were largely unaffected by parasitism during the final stadium although they were observed to increase earlier and decrease more rapidly in parasitized insects. We compare these results with those reported earlier for L. oleracea larvae parasitized by E. pennicornis as penultimate (fifth) instars, which display significantly depressed 20-E titres relative to control larvae. We conclude that E. pennicornis employs host endocrine-disruption strategies that differ according to whether the host is parasitized as a penultimate or final-stadium larva.
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effects of galanthus nivalis agglutinin gna expressed in tomato leaves on larvae of the tomato moth Lacanobia oleracea lepidoptera noctuidae and the effect of gna on the development of the endoparasitoid meteorus gyrator hymenoptera braconidae
Bulletin of Entomological Research, 2006Co-Authors: M E Wakefield, Elaine Fitches, John P Edwards, Howard A. Bell, Angharad M. R. GatehouseAbstract:The effect of ingestion of transgenic tomato leaves expressing the plant lectin Galanthus nivalis agglutinin (GNA) on development of larvae of Lacanobia oleracea (Linnaeus) was studied under laboratory conditions. When L. oleracea larvae were fed on tomato line 14.1H, expressing approximately 2.0% GNA, significant increases in the mean larval weight and in the amount of food consumed were found. This resulted in an overall reduction in the mean development time to the pupal stage of approximately 7 days. A significant increase in the percentage survival to the adult moth was also recorded when newly hatched larvae were reared on transgenic tomato leaves (72%) compared to larvae reared on untransformed leaves (40%). The effects of ingestion of GNA by L. oleracea larvae, via artificial diet or the leaves of transgenic tomato or potato plants, on the subsequent development of its solitary endoparasitoid Meteorus gyrator (Thunberg) was also studied. No significant effects on the life cycle parameters of M. gyrator developing in L. oleracea fed on GNA-containing diets were observed. Experiments with transgenic potato plants indicated that the stadium of the host larvae at parasitism had a greater influence on M. gyrator development than the presence of GNA. Potential GNA-binding glycoproteins were detected in the gut and body tissues of larval M. gyrator. Despite detection in host tissues, GNA could not be detected in adult M. gyrator and therefore it is likely that at the time of pupation M. gyrator are able to void the GNA in the meconial pellet.
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partial amino acid sequence and physiological effects of a 27 kda parasitism specific protein present in the plasma of parasitized Lacanobia oleracea noctuidae
Physiological Entomology, 2005Co-Authors: Elaine H Richards, B. Manderyck, John P EdwardsAbstract:Abstract. Parasitization of larvae of the tomato moth, Lacanonbia oleracea, by the ectoparasitic wasp, Eulophus pennicornis, results in the appearance of a 27 kDa parasitism-specific protein (PSP) in the plasma of the host. After isolation of this protein by native discontinuous polyacrylamide gel electrophoresis, whole gel elution and electroblotting, the N-terminal sequence of the 27 kDa PSP is determined by Edman degradation. The 20 amino acid residues obtained reveal 70% identity with a female-specific fat body protein from the moths Antheraea pernyi and Antheraea yamamai, 60% identity with a glutathione S-transferase (GST) isolated from Orthosia gothica, and a low level of identity with the N-termini of proteins belonging to the GST superfamily. Injection of the 27 kDa PSP into L. oleracea larvae has no significant effect on their ability to gain weight or the time at which they pupate. Furthermore, assays performed in vitro demonstrate that the 27 kDa PSP does not affect the ability of L. oleracea haemocytes to form aggregates. The precise source of the 27 kDa PSP remains unclear, although the current results suggest that it is most likely synthesized by host larvae in response to parasitism. The possible role(s) of the 27 kDa PSP are discussed with regard to the physiological effects of parasitism on the host.
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Partial amino acid sequence and physiological effects of a 27 kDa parasitism‐specific protein present in the plasma of parasitized Lacanobia oleracea (Noctuidae)
Physiological Entomology, 2005Co-Authors: Elaine H Richards, B. Manderyck, John P EdwardsAbstract:Abstract. Parasitization of larvae of the tomato moth, Lacanonbia oleracea, by the ectoparasitic wasp, Eulophus pennicornis, results in the appearance of a 27 kDa parasitism-specific protein (PSP) in the plasma of the host. After isolation of this protein by native discontinuous polyacrylamide gel electrophoresis, whole gel elution and electroblotting, the N-terminal sequence of the 27 kDa PSP is determined by Edman degradation. The 20 amino acid residues obtained reveal 70% identity with a female-specific fat body protein from the moths Antheraea pernyi and Antheraea yamamai, 60% identity with a glutathione S-transferase (GST) isolated from Orthosia gothica, and a low level of identity with the N-termini of proteins belonging to the GST superfamily. Injection of the 27 kDa PSP into L. oleracea larvae has no significant effect on their ability to gain weight or the time at which they pupate. Furthermore, assays performed in vitro demonstrate that the 27 kDa PSP does not affect the ability of L. oleracea haemocytes to form aggregates. The precise source of the 27 kDa PSP remains unclear, although the current results suggest that it is most likely synthesized by host larvae in response to parasitism. The possible role(s) of the 27 kDa PSP are discussed with regard to the physiological effects of parasitism on the host.
John A. Gatehouse - One of the best experts on this subject based on the ideXlab platform.
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sublethal effects of the insecticidal fusion protein ω actx hv1a gna on the parasitoid eulophus pennicornis via its host Lacanobia oleracea
Pest Management Science, 2016Co-Authors: Elaine Fitches, Erich Y. T. Nakasu, Filitsa Karamaouna, Georgios K Partsinevelos, Prashant Pyati, Hesham Abd El M Halim, John A. GatehouseAbstract:BACKGROUND The neurotoxin peptide ω-ACTX-Hv1a, fused to the carrier molecule GNA, presents potential for insect control as a biopesticide, being orally toxic to insect pests from different orders. However, thorough evaluation is required to assure its safety towards non-target invertebrates. Effects of this novel biopesticide on the parasitoid Eulophus pennicornis via its host Lacanobia oleracea are presented. RESULTS Hv1a/GNA did not cause mortality when injected or fed to fifth-stage L. oleracea, but caused up to 39% reduction in mean larval weight (P 0.05). The fusion protein was degraded by parasitoid larvae, rendering it non-toxic. CONCLUSION Hv1a/GNA has negligible effects on the parasitoid, even under worst-case scenarios. This low toxicity to these insects is of interest in terms of biopesticide specificity and safety to non-target organisms. © 2015 Society of Chemical Industry
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Sublethal effects of the insecticidal fusion protein ω-ACTX-Hv1a/GNA on the parasitoid Eulophus pennicornis via its host Lacanobia oleracea.
Pest Management Science, 2015Co-Authors: Erich Y. T. Nakasu, Elaine Fitches, John A. Gatehouse, Angharad M. R. Gatehouse, Filitsa Karamaouna, Georgios K Partsinevelos, Hesham M. Abd El Halim, Prashant Pyati, Martin G. EdwardsAbstract:BACKGROUND The neurotoxin peptide ω-ACTX-Hv1a, fused to the carrier molecule GNA, presents potential for insect control as a biopesticide, being orally toxic to insect pests from different orders. However, thorough evaluation is required to assure its safety towards non-target invertebrates. Effects of this novel biopesticide on the parasitoid Eulophus pennicornis via its host Lacanobia oleracea are presented. RESULTS Hv1a/GNA did not cause mortality when injected or fed to fifth-stage L. oleracea, but caused up to 39% reduction in mean larval weight (P 0.05). The fusion protein was degraded by parasitoid larvae, rendering it non-toxic. CONCLUSION Hv1a/GNA has negligible effects on the parasitoid, even under worst-case scenarios. This low toxicity to these insects is of interest in terms of biopesticide specificity and safety to non-target organisms. © 2015 Society of Chemical Industry
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a venom metalloproteinase from the parasitic wasp eulophus pennicornis is toxic towards its host tomato moth Lacanobia oleracae
Insect Molecular Biology, 2009Co-Authors: Daniel R G Price, Elaine Fitches, Robert J. Weaver, Howard A. Bell, Gareth Hinchliffe, John A. GatehouseAbstract:Abstract Three genes encoding clan MB metalloproteinases (EpMP1-3) were identified from venom glands of the ectoparasitic wasp Eulophus pennicornis. The derived amino acid sequences predict mature proteins of approximately 46 kDa, with a novel two-domain structure comprising a C-terminal reprolysin domain, and an N-terminal domain of unknown function. EpMP3 expressed as a recombinant protein in Pichia pastoris had gelatinase activity, which was inhibited by EDTA. Injection of recombinant EpMP3 into fifth instar Lacanobia oleracea (host) larvae resulted in partial insect mortality associated with the moult to sixth instar, with surviving insects showing retarded development and growth. EpMP3 is expressed specifically in venom glands. These results suggest that EpMP3 is a functional component of Eulophus venom, which is able to manipulate host development.
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Cloning, expression and functional characterisation of chitinase from larvae of tomato moth (Lacanobia oleracea): a demonstration of the insecticidal activity of insect chitinase.
Insect Biochemistry and Molecular Biology, 2004Co-Authors: Elaine Fitches, John A. Gatehouse, Howard A. Bell, Hillary S Wilkinson, David P. Bown, John P EdwardsAbstract:Abstract Chitinases are vital to moulting in insects, and may also affect gut physiology through their involvement in peritrophic membrane turnover. A cDNA encoding chitinase was cloned from larvae of tomato moth (Lacanobia oleracea), a Lepidopteran pest of crops. The predicted protein contains 553 amino acid residues, with a signal peptide of 20 a.a. Sequence comparison showed 75–80% identity with other Lepidopteran chitinases. L. oleracea chitinase was produced as a functional recombinant enzyme in the yeast Pichia pastoris. A fusion protein containing chitinase joined to the N-terminus of snowdrop lectin (GNA) was also produced, to determine whether GNA could deliver chitinase to the haemolymph of Lepidopteran larvae after oral ingestion. The purified recombinant proteins exhibited similar levels of chitinase activity in vitro. Both proteins were highly toxic to L. oleracea larvae on injection, causing 100% mortality at low dose (2.5 μg/g insect). Injection of chitinase prior to the moult resulted in decreased cuticle thickness. The recombinant proteins caused chronic effects when fed, causing reductions in larval growth and food consumption by up to 60%. The oral toxicity of chitinase was not increased by attaching GNA in the fusion protein, due to degradation in the larval gut, preventing GNA acting as a “carrier”.
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fusion proteins containing insect specific toxins as pest control agents snowdrop lectin delivers fused insecticidal spider venom toxin to insect haemolymph following oral ingestion
Journal of Insect Physiology, 2004Co-Authors: Elaine Fitches, John P Edwards, Angharad M. R. Gatehouse, Martin G. Edwards, Christopher Mee, Eugene V Grishin, John A. GatehouseAbstract:Abstract The mannose-specific snowdrop lectin (Galanthus nivalis agglutinin: GNA), when fed to insects, binds to the gut epithelium and passes into the haemolymph. The ability of GNA to act as a carrier protein to deliver an insecticidal spider venom neurotoxin (Segestria florentina toxin 1: SFI1) to the haemolymph of lepidopteran larvae was investigated. Constructs encoding SFI1 and an SFI1/GNA fusion protein were expressed in Pichia pastoris. The insecticidal activity of purified recombinant proteins on injection was found to be comparable to published values for SfI1 purified from spider venom [Toxicon 40 (2002) 125]. Whereas neither GNA nor SFI1 alone showed acute toxicity when fed to larvae of tomato moth (Lacanobia oleracea), feeding SFI1/GNA fusion at 2.5% of dietary proteins was insecticidal to first stadium larvae, causing 100% mortality after 6 days. The protein also showed a significant, dose dependent, toxicity towards fourth and fifth stadium larvae, with growth reduced by up to approximately 90% over a 4-day assay period compared to controls. Delivery of intact SFI1/GNA to the haemolymph in these insects was shown by western blotting; haemolymph samples from fusion-fed larvae contained a GNA-immunoreactive protein of the same molecular weight as the SFI1/GNA fusion. SFI1/GNA and similar fusion proteins offer a novel and effective approach for delivering haemolymph active toxins by oral administration, which could be used in crop protection by expression in transgenic plants.
Howard A. Bell - One of the best experts on this subject based on the ideXlab platform.
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the snowdrop lectin galanthus nivalis agglutinin gna and a fusion protein butait gna have a differential affect on a pest noctuid Lacanobia oleracea and the ectoparasitoid eulophus pennicornis
Physiological Entomology, 2010Co-Authors: M E Wakefield, Elaine Fitches, Howard A. Bell, Angharad M. R. GatehouseAbstract:Fusion proteins have considerable potential as novel insect control agents because they enable the oral delivery of insecticidal peptides to the haemolymph of pests. Transport is achieved via fusion of the toxin to a carrier protein Galanthus nivalis agglutinin (GNA) that, after ingestion, binds to and crosses the insect gut epithelia. A fusion protein comprising a toxin from the South Indian red scorpion (Mesobuthus tamulus) that is fused to a GNA polypeptide (ButaIT/GNA) has a detrimental effect on the development of tomato moth Lacanobia oleracea (L.) (Lepidoptera: Noctuidae) larvae. The present study examines the effects of ButaIT/GNA and GNA, delivered orally or by injection, on the development of L. oleracea larvae, and the subsequent effects on the gregarious ectoparasitoid Eulophus pennicornis (Nees) (Hymenoptera: Eulophidae) developing on ButaIT/GNA- and GNA-treated hosts. The fusion protein, but not GNA, reduces the growth of fifth stadium L. oleracea larvae. The development of E. pennicornis is not affected by the presence of ButaIT/GNA in hosts that ingest the protein, although it is affected when hosts are injected with the protein. This difference is considered to be a result of higher levels of fusion protein being present when the fusion protein is injected. Intact ButaIT/GNA is detected by immunoassay in the haemolymph of L. oleracea larvae after ingestion of the fusion protein. More unexpectedly, negative effects are observed for the growth of E. pennicornis larvae developing on hosts that have either ingested, or been injected with GNA.
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The snowdrop lectin Galanthus nivalis agglutinin (GNA) and a fusion protein ButaIT/GNA have a differential affect on a pest noctuid Lacanobia oleracea and the ectoparasitoid Eulophus pennicornis
Physiological Entomology, 2010Co-Authors: M E Wakefield, Elaine Fitches, Howard A. Bell, Angharad M. R. GatehouseAbstract:Fusion proteins have considerable potential as novel insect control agents because they enable the oral delivery of insecticidal peptides to the haemolymph of pests. Transport is achieved via fusion of the toxin to a carrier protein Galanthus nivalis agglutinin (GNA) that, after ingestion, binds to and crosses the insect gut epithelia. A fusion protein comprising a toxin from the South Indian red scorpion (Mesobuthus tamulus) that is fused to a GNA polypeptide (ButaIT/GNA) has a detrimental effect on the development of tomato moth Lacanobia oleracea (L.) (Lepidoptera: Noctuidae) larvae. The present study examines the effects of ButaIT/GNA and GNA, delivered orally or by injection, on the development of L. oleracea larvae, and the subsequent effects on the gregarious ectoparasitoid Eulophus pennicornis (Nees) (Hymenoptera: Eulophidae) developing on ButaIT/GNA- and GNA-treated hosts. The fusion protein, but not GNA, reduces the growth of fifth stadium L. oleracea larvae. The development of E. pennicornis is not affected by the presence of ButaIT/GNA in hosts that ingest the protein, although it is affected when hosts are injected with the protein. This difference is considered to be a result of higher levels of fusion protein being present when the fusion protein is injected. Intact ButaIT/GNA is detected by immunoassay in the haemolymph of L. oleracea larvae after ingestion of the fusion protein. More unexpectedly, negative effects are observed for the growth of E. pennicornis larvae developing on hosts that have either ingested, or been injected with GNA.
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The biological effects of venom derived from the ectoparasitic wasp Eulophus pennicornis (Nees) (Hymenoptera: Eulophidae): evidence for dual endocrine regulation.
The Open Entomology Journal, 2010Co-Authors: Howard A. Bell, Michelle E. Powell, Dan R.g. Price, Robert J. WeaverAbstract:The venom of the ectoparasitoid Eulophus pennicornis is known to induce developmental arrest in parasitized hosts through the prevention of moulting. However, little work has explored how the venom affects different host stages, whether the observed effects vary with different doses, and whether the venom has activity in non-host species. Injections of venom doses of � 0.5 � g protein prevented the development of >90% of both fifth and sixth instar Lacanobia oleracea larvae. In fifth instars, developmental arrest at doses of � 1.0 � g occurred prior to ecdysis to the sixth stadium, whilst the 0.5 and 0.25 � g treatments allowed 36% and 77% of injected larvae, respectively, to moult although most sub- sequently failed to pupate. Although naturally parasitized hosts always showed reduced growth, lower doses of venom of- ten prevented pupation without affecting this parameter, particularly in sixth instar larvae where only the highest dose (2.0 � g) reduced the mean maximum weights achieved. Two factitious lepidopteran hosts, Manduca sexta and Spodoptera lit- toralis, were also affected by injection of the venom at w/w doses equivalent to those used for L. oleracea although larval- larval moulting was only prevented in the former. Fractionation of venom using gel-filtration FPLC indicated the presence of at least two factors that markedly affected host development. One series of contiguous fractions, on injection, prevented larval-larval ecdysis in a similar way to whole venom. A second series of fractions had no effect on larval-larval ecdysis but resulted in the formation of deformed pupae, an effect that closely resembled the application of a juvenile hormone (JH) analogue, which may indicate the presence of a factor within the venom that modulates host levels of this hormone.
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Longevity and fecundity of Eulophus pennicornis, an ectoparasitoid of the tomato moth Lacanobia oleracea, is affected by nutritional state and diet quality
Agricultural and Forest Entomology, 2010Co-Authors: M E Wakefield, Howard A. Bell, Angharad M. R. GatehouseAbstract:1 Adult female Eulophus pennicornis require a source of nutrition, provided by sources such as pollen, nectar and honeydew or by host feeding, to promote longevity and facilitate egg production. There is potential for parasitoids to be exposed directly to contaminants, including gene products in transgenic crops, through feeding on plant materials, honeydew or hosts. Among such potential contaminants are lectins such as Galanthus nivalis agglutinin (GNA) and concanavalin agglutinin (Con A). 2 The effect of direct exposure to honey diets containing GNA and Con A on the longevity and fecundity of E. pennicornis was examined. These lectins have been expressed in a number of plant species for the control for various insect pests. Both GNA and Con A significantly reduced longevity and fecundity at the highest concentration used (0.5% w/v). The effect on fecundity was shown to be related to a reduction in longevity. 3 Examination of the gustatory response of adult female E. pennicornis to honey diet containing 1% w/v GNA or Con A revealed no significant differences in consumption rate on first exposure. A significant reduction in the time spent feeding on diet containing 1% Con A was found on the second exposure to the diet. This could have been the result of either a conditioned aversion response or the intoxication of the insect. The effect of Con A on longevity and fecundity could have been, in part, a result of reduced food intake. 4 Studies on nutrition and egg resorption demonstrated that the availability of honey solution prolongs the longevity of E. pennicornis and the lack of a source of nutrition promotes oosorption. 5 A greater understanding of feeding behaviour and ovigeny is required to understand fully the potential ecological consequence of transgenic crops on parasitoid species through routes of direct exposure to transgene products.
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a venom metalloproteinase from the parasitic wasp eulophus pennicornis is toxic towards its host tomato moth Lacanobia oleracae
Insect Molecular Biology, 2009Co-Authors: Daniel R G Price, Elaine Fitches, Robert J. Weaver, Howard A. Bell, Gareth Hinchliffe, John A. GatehouseAbstract:Abstract Three genes encoding clan MB metalloproteinases (EpMP1-3) were identified from venom glands of the ectoparasitic wasp Eulophus pennicornis. The derived amino acid sequences predict mature proteins of approximately 46 kDa, with a novel two-domain structure comprising a C-terminal reprolysin domain, and an N-terminal domain of unknown function. EpMP3 expressed as a recombinant protein in Pichia pastoris had gelatinase activity, which was inhibited by EDTA. Injection of recombinant EpMP3 into fifth instar Lacanobia oleracea (host) larvae resulted in partial insect mortality associated with the moult to sixth instar, with surviving insects showing retarded development and growth. EpMP3 is expressed specifically in venom glands. These results suggest that EpMP3 is a functional component of Eulophus venom, which is able to manipulate host development.
Angharad M. R. Gatehouse - One of the best experts on this subject based on the ideXlab platform.
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Sublethal effects of the insecticidal fusion protein ω-ACTX-Hv1a/GNA on the parasitoid Eulophus pennicornis via its host Lacanobia oleracea.
Pest Management Science, 2015Co-Authors: Erich Y. T. Nakasu, Elaine Fitches, John A. Gatehouse, Angharad M. R. Gatehouse, Filitsa Karamaouna, Georgios K Partsinevelos, Hesham M. Abd El Halim, Prashant Pyati, Martin G. EdwardsAbstract:BACKGROUND The neurotoxin peptide ω-ACTX-Hv1a, fused to the carrier molecule GNA, presents potential for insect control as a biopesticide, being orally toxic to insect pests from different orders. However, thorough evaluation is required to assure its safety towards non-target invertebrates. Effects of this novel biopesticide on the parasitoid Eulophus pennicornis via its host Lacanobia oleracea are presented. RESULTS Hv1a/GNA did not cause mortality when injected or fed to fifth-stage L. oleracea, but caused up to 39% reduction in mean larval weight (P 0.05). The fusion protein was degraded by parasitoid larvae, rendering it non-toxic. CONCLUSION Hv1a/GNA has negligible effects on the parasitoid, even under worst-case scenarios. This low toxicity to these insects is of interest in terms of biopesticide specificity and safety to non-target organisms. © 2015 Society of Chemical Industry
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the snowdrop lectin galanthus nivalis agglutinin gna and a fusion protein butait gna have a differential affect on a pest noctuid Lacanobia oleracea and the ectoparasitoid eulophus pennicornis
Physiological Entomology, 2010Co-Authors: M E Wakefield, Elaine Fitches, Howard A. Bell, Angharad M. R. GatehouseAbstract:Fusion proteins have considerable potential as novel insect control agents because they enable the oral delivery of insecticidal peptides to the haemolymph of pests. Transport is achieved via fusion of the toxin to a carrier protein Galanthus nivalis agglutinin (GNA) that, after ingestion, binds to and crosses the insect gut epithelia. A fusion protein comprising a toxin from the South Indian red scorpion (Mesobuthus tamulus) that is fused to a GNA polypeptide (ButaIT/GNA) has a detrimental effect on the development of tomato moth Lacanobia oleracea (L.) (Lepidoptera: Noctuidae) larvae. The present study examines the effects of ButaIT/GNA and GNA, delivered orally or by injection, on the development of L. oleracea larvae, and the subsequent effects on the gregarious ectoparasitoid Eulophus pennicornis (Nees) (Hymenoptera: Eulophidae) developing on ButaIT/GNA- and GNA-treated hosts. The fusion protein, but not GNA, reduces the growth of fifth stadium L. oleracea larvae. The development of E. pennicornis is not affected by the presence of ButaIT/GNA in hosts that ingest the protein, although it is affected when hosts are injected with the protein. This difference is considered to be a result of higher levels of fusion protein being present when the fusion protein is injected. Intact ButaIT/GNA is detected by immunoassay in the haemolymph of L. oleracea larvae after ingestion of the fusion protein. More unexpectedly, negative effects are observed for the growth of E. pennicornis larvae developing on hosts that have either ingested, or been injected with GNA.
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The snowdrop lectin Galanthus nivalis agglutinin (GNA) and a fusion protein ButaIT/GNA have a differential affect on a pest noctuid Lacanobia oleracea and the ectoparasitoid Eulophus pennicornis
Physiological Entomology, 2010Co-Authors: M E Wakefield, Elaine Fitches, Howard A. Bell, Angharad M. R. GatehouseAbstract:Fusion proteins have considerable potential as novel insect control agents because they enable the oral delivery of insecticidal peptides to the haemolymph of pests. Transport is achieved via fusion of the toxin to a carrier protein Galanthus nivalis agglutinin (GNA) that, after ingestion, binds to and crosses the insect gut epithelia. A fusion protein comprising a toxin from the South Indian red scorpion (Mesobuthus tamulus) that is fused to a GNA polypeptide (ButaIT/GNA) has a detrimental effect on the development of tomato moth Lacanobia oleracea (L.) (Lepidoptera: Noctuidae) larvae. The present study examines the effects of ButaIT/GNA and GNA, delivered orally or by injection, on the development of L. oleracea larvae, and the subsequent effects on the gregarious ectoparasitoid Eulophus pennicornis (Nees) (Hymenoptera: Eulophidae) developing on ButaIT/GNA- and GNA-treated hosts. The fusion protein, but not GNA, reduces the growth of fifth stadium L. oleracea larvae. The development of E. pennicornis is not affected by the presence of ButaIT/GNA in hosts that ingest the protein, although it is affected when hosts are injected with the protein. This difference is considered to be a result of higher levels of fusion protein being present when the fusion protein is injected. Intact ButaIT/GNA is detected by immunoassay in the haemolymph of L. oleracea larvae after ingestion of the fusion protein. More unexpectedly, negative effects are observed for the growth of E. pennicornis larvae developing on hosts that have either ingested, or been injected with GNA.
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Longevity and fecundity of Eulophus pennicornis, an ectoparasitoid of the tomato moth Lacanobia oleracea, is affected by nutritional state and diet quality
Agricultural and Forest Entomology, 2010Co-Authors: M E Wakefield, Howard A. Bell, Angharad M. R. GatehouseAbstract:1 Adult female Eulophus pennicornis require a source of nutrition, provided by sources such as pollen, nectar and honeydew or by host feeding, to promote longevity and facilitate egg production. There is potential for parasitoids to be exposed directly to contaminants, including gene products in transgenic crops, through feeding on plant materials, honeydew or hosts. Among such potential contaminants are lectins such as Galanthus nivalis agglutinin (GNA) and concanavalin agglutinin (Con A). 2 The effect of direct exposure to honey diets containing GNA and Con A on the longevity and fecundity of E. pennicornis was examined. These lectins have been expressed in a number of plant species for the control for various insect pests. Both GNA and Con A significantly reduced longevity and fecundity at the highest concentration used (0.5% w/v). The effect on fecundity was shown to be related to a reduction in longevity. 3 Examination of the gustatory response of adult female E. pennicornis to honey diet containing 1% w/v GNA or Con A revealed no significant differences in consumption rate on first exposure. A significant reduction in the time spent feeding on diet containing 1% Con A was found on the second exposure to the diet. This could have been the result of either a conditioned aversion response or the intoxication of the insect. The effect of Con A on longevity and fecundity could have been, in part, a result of reduced food intake. 4 Studies on nutrition and egg resorption demonstrated that the availability of honey solution prolongs the longevity of E. pennicornis and the lack of a source of nutrition promotes oosorption. 5 A greater understanding of feeding behaviour and ovigeny is required to understand fully the potential ecological consequence of transgenic crops on parasitoid species through routes of direct exposure to transgene products.
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effects of galanthus nivalis agglutinin gna expressed in tomato leaves on larvae of the tomato moth Lacanobia oleracea lepidoptera noctuidae and the effect of gna on the development of the endoparasitoid meteorus gyrator hymenoptera braconidae
Bulletin of Entomological Research, 2006Co-Authors: M E Wakefield, Elaine Fitches, John P Edwards, Howard A. Bell, Angharad M. R. GatehouseAbstract:The effect of ingestion of transgenic tomato leaves expressing the plant lectin Galanthus nivalis agglutinin (GNA) on development of larvae of Lacanobia oleracea (Linnaeus) was studied under laboratory conditions. When L. oleracea larvae were fed on tomato line 14.1H, expressing approximately 2.0% GNA, significant increases in the mean larval weight and in the amount of food consumed were found. This resulted in an overall reduction in the mean development time to the pupal stage of approximately 7 days. A significant increase in the percentage survival to the adult moth was also recorded when newly hatched larvae were reared on transgenic tomato leaves (72%) compared to larvae reared on untransformed leaves (40%). The effects of ingestion of GNA by L. oleracea larvae, via artificial diet or the leaves of transgenic tomato or potato plants, on the subsequent development of its solitary endoparasitoid Meteorus gyrator (Thunberg) was also studied. No significant effects on the life cycle parameters of M. gyrator developing in L. oleracea fed on GNA-containing diets were observed. Experiments with transgenic potato plants indicated that the stadium of the host larvae at parasitism had a greater influence on M. gyrator development than the presence of GNA. Potential GNA-binding glycoproteins were detected in the gut and body tissues of larval M. gyrator. Despite detection in host tissues, GNA could not be detected in adult M. gyrator and therefore it is likely that at the time of pupation M. gyrator are able to void the GNA in the meconial pellet.
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Infection by the microsporidium Vairimorpha necatrix (Microspora: Microsporidia) elevates juvenile hormone titres in larvae of the tomato moth, Lacanobia oleracea (Lepidoptera: Noctuidae).
Journal of Invertebrate Pathology, 2007Co-Authors: Rachel E. Down, John P Edwards, Howard A. Bell, Anne E. Kirkbride-smith, Gareth Bryning, Robert J. WeaverAbstract:The effects of infection by a microsporidium, Vairimorpha necatrix (Kramer), on the endogenous levels of juvenile hormones in tomato moth (Lacanobia oleracea L.) larvae were investigated. Levels of juvenile hormone II (JH II) were 10-fold greater in the infected larvae on day two of the sixth stadium but no significant difference was observed on day seven. Juvenile hormone I (JH I) was also detected in day two and day seven sixth instar infected larvae but was not detected in non-infected larvae. The duration of the fifth and sixth stadia was significantly longer for infected larvae when compared with non-infected larvae. No evidence was found to suggest that supernumerary moults are a feature of infection by V. necatrix in L. oleracea larvae. Experiments were performed to determine whether the elevation in JH levels, which probably prevents pupation, is an adaptive mechanism of the microsporidium for extending the growth phase of the host, thereby allowing increased spore production. A proportion of infected larvae were collected on days 9 and 24 of the sixth stadium and spore extracts prepared from each larva. These days represent the average duration of the sixth stadium required for uninfected larvae to reach pupation, and the average number of days that V. necatrix-infected larvae survive in the sixth stadium before dying from infection. The mean spore yields from infected larvae 24 days into the sixth stadium were significantly higher than the spore yields obtained from day nine sixth instar larvae. The hypothesis that V. necatrix manipulates host endocrinology (i.e. prolong the host larval state to maximise spore yield) is discussed in context with the results obtained.
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Interactions between the solitary endoparasitoid, Meteorus gyrator (Hymenoptera: Braconidae) and its host, Lacanobia oleracea (Lepidoptera: Noctuidae), infected with the entomopathogenic microsporidium, Vairimorpha necatrix (Microspora: Microsporidia
Bulletin of Entomological Research, 2005Co-Authors: Rachel E. Down, Howard A. Bell, F. Smethurst, John P EdwardsAbstract:Infection of Lacanobia oleracea (Linnaeus) larvae with the microsporidium Vairimorpha necatrix (Kramer) resulted in significant effects on the survival and development of the braconid parasitoid, Meteorus gyrator (Thunberg). Female M. gyrator did not show any avoidance of V. necatrix-infected hosts when they were selecting hosts for oviposition. When parasitism occurred at the same time as infection by the pathogen, or up to four days later, no significant detrimental effects on the parasitoid were observed. However, when parasitism occurred six to eight days after infection, a greater proportion (12.5-14%) of hosts died before parasitoid larvae egressed. Successful eclosion of adult wasps was also reduced. When parasitism and infection were concurrent, parasitoid larval development was significantly faster in infected hosts, and cocoons were significantly heavier. However, as the time interval between infection and parasitism increased, parasitoid larval development was significantly extended by up to two days, and the cocoons formed were significantly (c. 20%) smaller. Vairimorpha necatrix spores were ingested by the developing parasitoid larvae, accumulated in the occluded midgut, and were excreted in the meconium upon pupation.
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Effect of microsporidian infection in Lacanobia oleracea (Lep., Noctuidae) on prey selection and consumption by the spined soldier bug Podisus maculiventris (Het., Pentatomidae)
Journal of Applied Entomology, 2004Co-Authors: Howard A. Bell, Rachel E. Down, Anne E. Kirkbride-smith, John P EdwardsAbstract:: The predatory behaviour of Podisus maculiventris was investigated when this bug was presented with Lacanobia oleracea larvae infected with the microsporidian pathogen Vairimorpha necatrix. In choice tests, adult predatory bugs attacked V. necatrix-infected L. oleracea prey in similar numbers to uninfected larvae. Exposure to infected prey during nymphal development increased the rate at which adult bugs attacked diseased L. oleracea larvae. Fifth instar P. maculiventris nymphs, however, attacked infected prey in the majority of cases (>80% of occasions). Consumption of healthy and infected prey was measured for both adult and nymphal bugs. Over the course of 1 week, the mean number of V. necatrix-infected prey eaten by P. maculiventris adults (7.0 ± 0.82) was approximately twice the number of uninfected prey consumed (3.8 ± 0.42). Similarly, the number of prey larvae attacked by the bug over the course of the final nymphal stadium was also increased, with 2.9 ± 0.42 uninfected larvae eaten as opposed to 4.9 ± 0.27 V. necatrix-infected prey. However, small-scale investigations into the rate of P. maculiventris reduced small populations of L. oleracea indicated that the combination of the predator and pathogen would produce, at best, an additive effect.
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The pathogenicity of Vairimorpha necatrix (Microspora: Microsporidia) against the tomato moth, Lacanobia oleracea (Lepidoptera: Noctuidae) and its potential use for the control of lepidopteran glasshouse pests
Pest Management Science, 2004Co-Authors: Rachel E. Down, Howard A. Bell, Anne E. Kirkbride-smith, John P EdwardsAbstract:A droplet feeding technique was used to feed known amounts of Vairimorpha necatrix (Kramer) spores to larvae of the tomato moth, Lacanobia oleracea (L) in order to assess the susceptibility of this lepidopteran pest to the pathogen. All first- to fourth-instar larvae died as a result of ingesting 1000 or more V necatrix spores. Two forms of death were observed, which were dependent on the dose and the age of the insect when treated. For first-instar larvae, rapid death (within 6 days of dosing) occurred after ingestion of 2000 spores, whereas lower doses resulted in a proportion of larvae dying from chronic infection (microsporidiosis). For more advanced stages, increasing spore doses were required to give rapid death, such that a dose of 200 000 spores was needed to give 80% mortality within 6 days for third-instar larvae. Rapid death was not observed in fourth- to sixth-instar larvae. In all cases successful pupation and adult emergence were much reduced compared with non-infected larvae. Suspensions of V necatrix were sprayed on to tomato (Lycopersicon esculentum Mill) plants maintained in small glasshouses prior to infestation of the plants with L oleracea larvae. The numbers and biomass of pest larvae retrieved from the plants sprayed with V necatrix were significantly reduced by up to 40% and 70%, respectively, compared with plants sprayed with water (control). Similarly, plants sprayed with V necatrix showed a reduction in damage of up to 45% compared with the control plants.
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Dissemination of the biocontrol agent Vairimorpha necatrix by the spined soldier bug, Podisus maculiventris
Entomologia Experimentalis Et Applicata, 2004Co-Authors: Rachel E. Down, Howard A. Bell, Anne E. Kirkbride-smith, H. June Matthews, John P EdwardsAbstract:The ability of the spined soldier bug, Podisus maculiventris (Say) (Heteroptera: Pentatomidae), to disseminate infective forms of two lepidopteran pathogens, Vairimorpha necatrix (Kramer) (Microspora: Microsporidia) and Lacanobia oleracea granulovirus (LoGV) was investigated. Individual female P. maculiventris that had fed on Lacanobia oleracea L. (Lepidoptera: Noctuidae) larvae, infected with V. necatrix, excreted approximately 6 × 10 8 V. necatrix spores during the subsequent 7 days. Excreted spores were fed to L. oleracea larvae, causing 100% mortality, indicating that the spores remained viable after passing through the gut of the predator. Podisus maculiventris that had fed on V necatrix or LoGV-infected larvae were allowed to defecate on the foliage of tomato plants, prior to the infestation of the plants with L. oleracea or Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae) larvae. This proved to be an effective way of infecting the pest larvae with the pathogens, particularly when five predatory bugs were used per plant. After 20 days, the number of S. littoralis and L. oleracea surviving on the plants was reduced by 75% and 61%, respectively. Female P. maculiventris maintained on V necatrix-infected prey showed reduced egg production and longevity, whilst those fed on LoGV-infected prey showed only reduced egg production. The potential for P. maculiventris to disseminate insect pathogens is discussed in the context of improved biological control of lepidopteran pests.
