Publications
Title | Abstract | Year(sorted descending) Filter | PMID Filter |
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a cry1ac toxin variant generated by directed evolution has enhanced toxicity against lepidopteran insects. | cry1ac insecticidal crystal proteins produced by bacillus thuringiensis (bt) have become an important natural biological agent for the control of lepidopteran insects. in this study, a cry1ac toxin gene from bacillus thuringiensis 4.0718 was modified by using error-prone pcr, staggered extension process (step) shuffling combined with red/et homologous recombination to investigate the insecticidal activity of delta-endotoxin cry1ac. a cry1ac toxin variant (designated as t524n) screened by insect ... | 2011 | 20669019 |
kinetic characterization of the group ii helicoverpa armigera nucleopolyhedrovirus propagated in suspension cell cultures: implications for development of a biopesticides production process. | large-scale commercialization of baculovirus biopesticides for the control of insect pests requires a cell culture production process, and knowledge of the infection kinetics is a vital prerequisite for process optimization. well-characterized kinetic parameters have so far only been reported for the commercially established recombinant autographa californica nucleopolyhedrovirus (acmnpv), a group i npv. in this work, key infection kinetic parameters of the group ii npv helicoverpa armigera nucl ... | 2011 | 21644255 |
bacillus thuringiensis protein cry6b (bgsc id 4d8) is toxic to larvae of hypera postica. | insecticidal proteins produced by strains of bacillus thuringenesis are specific toward target pests. one of the bt proteins, cry 1ac has been used successfully for controlling crop predation by polyphagous pests helicoverpa armigera. structurally, bt proteins consist of three domains; domain i and iii are fairly homologous in various bt proteins while domain ii is hypervariable. the hypervariable domain ii is believed to be responsible for specificity toward target pest. successful deployment o ... | 2011 | 20835830 |
comparative characterization of chitinases from silkworm (bombyx mori) and bollworm (helicoverpa armigera). | chitinases play an important role in the degradation of the cuticular chitin during the process of ecdysis. in this study, we compared the chitinases of two insect species, bombyx mori (silkworm) and helicoverpa armigera (bollworm), to assess the relation between characteristics and chitinase patterns. differences between two chitinases were observed after purification using ammonium sulfate precipitation, affinity chromatography, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (sd ... | 2011 | 21573993 |
discovery of an unusual biosynthetic origin for circular proteins in legumes. | cyclotides are plant-derived proteins that have a unique cyclic cystine knot topology and are remarkably stable. their natural function is host defense, but they have a diverse range of pharmaceutically important activities, including uterotonic activity and anti-hiv activity, and have also attracted recent interest as templates in drug design. here we report an unusual biosynthetic origin of a precursor protein of a cyclotide from the butterfly pea, clitoria ternatea, a representative member of ... | 2011 | 21593408 |
helicoverpa armigera nucleopolyhedrovirus occlusion-derived virus-associated protein, ha100, affects oral infectivity in vivo but not virus replication in vitro. | orf100 (ha100) of helicoverpa armigera nucleopolyhedrovirus (hearnpv) has been reported as one of the unique genes of group ii alphabaculoviruses encoding a protein located in the occlusion-derived virus (odv) envelope and nucleocapsid. the protein consists of 510 aa with a predicted mass of 58.1 kda and is a homologue of poly(adp-ribose) glycohydrolase in eukaryotes. western blot analysis detected a 60 kda band in hearnpv-infected hzam1 cells starting at 18 h post-infection. transient expressio ... | 2011 | 21325478 |
relationships between exogenous-toxin quantity and increased biomass of transgenic bt crops under elevated carbon dioxide. | field-otc experiments were conducted with the goals of ascertaining if increased biomass in bt transgenic cotton and rice grown under elevated co(2) results in diminished exogenous-bt toxin, and assessing the effectiveness of bt transgenes against lepidopteran pests. bt cotton responded differently, in terms of bt-toxin quantity, than bt rice, and both indicated differences among developmental stages. dramatic biomass increase significantly diluted bt-toxin content in 45-das ("days after seedlin ... | 2011 | 21349582 |
spider toxin (hvt) gene cloned under phloem specific rss1 and rolc promoters provides resistance against american bollworm (heliothis armigera). | spider venoms are neurotoxin proteins that can kill insects. spider toxin hvt gene was cloned under two phloem specific rss1 and rolc promoters, transformed into tobacco plants through agrobacterium-mediated transformation and tested against heliothis armigera larvae. transgenic plants were confirmed through pcr. first instar larvae of h. armigera were released on detached leaves of transformed and non-transformed plants. insect bioassays showed 93-100% mortality of h. armigera larvae within 72 ... | 2011 | 21369907 |
a btb domain-containing gene is upregulated by immune challenge. | 20-hydroxyecdysone (20e) is an important hormone that regulates the development of insects. although previous evidence revealed that 20e promotes innate immunity in insects, the mechanism involved is still unclear. in this study, the habbp gene from helicoverpa armigera is cloned, which contains btb (broad-complex, tramtrack, and bric-a-brac), a back (btb and carboxyl-terminus kelch repeats), and phr (pam, highwire, and rpm) domains. rt-pcr analysis of habbp and western blot analysis of habbp sh ... | 2011 | 21374716 |
reduced levels of membrane-bound alkaline phosphatase are common to lepidopteran strains resistant to cry toxins from bacillus thuringiensis. | development of insect resistance is one of the main concerns with the use of transgenic crops expressing cry toxins from the bacterium bacillus thuringiensis. identification of biomarkers would assist in the development of sensitive dna-based methods to monitor evolution of resistance to bt toxins in natural populations. we report on the proteomic and genomic detection of reduced levels of midgut membrane-bound alkaline phosphatase (malp) as a common feature in strains of cry-resistant heliothis ... | 2011 | 21390253 |
genetic variation and virulence of nucleopolyhedroviruses isolated worldwide from the heliothine pests helicoverpa armigera, helicoverpa zea, and heliothis virescens. | to assess the diversity and relationships of baculoviruses found in insects of the heliothine pest complex, a pcr-based method was used to classify 90 samples of nucleopolyhedrovirus (npv; baculoviridae: alphabaculovirus) obtained worldwide from larvae of heliothis virescens, helicoverpa zea, and helicoverpa armigera. partial nucleotide sequencing and phylogenetic analysis of three highly conserved genes (lef-8, lef-9, and polh) indicated that 67 of these samples contained isolates of the h. zea ... | 2011 | 21439295 |
sialome of a generalist lepidopteran herbivore: identification of transcripts and proteins from helicoverpa armigera labial salivary glands. | although the importance of insect saliva in insect-host plant interactions has been acknowledged, there is very limited information on the nature and complexity of the salivary proteome in lepidopteran herbivores. we inspected the labial salivary transcriptome and proteome of helicoverpa armigera, an important polyphagous pest species. to identify the majority of the salivary proteins we have randomly sequenced 19,389 expressed sequence tags (ests) from a normalized cdna library of salivary glan ... | 2011 | 22046331 |
isolation and identification of insect intestinal mucin haiim86--the new target for helicoverpa armigera biocontrol. | there are many more glycoproteins in helicoverpa armigera peritrophic membrane than midgut separated by sds-page analysis after periodic acid-schiff (pas) and coomassie staining. the peritrophic membrane (pm) of h. armigera larvae contains about forty associated proteins. a cdna library was constructed from h. armigera midgut mrna to study the new target for pest biocontrol. an antiserum against spodoptera exigua integral/total pm proteins cross reacted with several h. armigera pm proteins and w ... | 2011 | 21448339 |
identification of gene expression changes associated with the initiation of diapause in the brain of the cotton bollworm, helicoverpa armigera. | diapause, a state of arrested development accompanied by a marked decrease of metabolic rate, helps insects to overcome unfavorable seasons. helicoverpa armigera (har) undergoes pupal diapause, but the molecular mechanism of diapause initiation is unclear. using suppression subtractive hybridization (ssh), we investigated differentially expressed genes in diapause- and nondiapause-destined pupal brains at diapause initiation. | 2011 | 21569297 |
antifeedant and larvicidal activities of rhein isolated from the flowers of cassia fistula l. | antifeedant and larvicidal activities of rhein (1,8-dihydroxyanthraquinone-3-carboxylic acid) isolated from the ethyl acetate extract of cassia fistula flower were studied against lepidopteron pests spodoptera litura and helicoverpa armigera. significant antifeedant activity was observed against h. armigera (76.13%) at 1000 ppm concentration. rhein exhibited larvicidal activity against h. armigera (67.5), s. litura (36.25%) and the lc50 values was 606.50 ppm for h. armigera and 1192.55 ppm for s ... | 2011 | 23961115 |
relationships of helicoverpa armigera, ostrinia nubilalis and fusarium verticillioides on mon 810 maize. | mon 810 maize was developed against ostrinia nubilalis and is suggested to indirectly decrease fusarium spp. infestation in maize ears. to evaluate this effect, co-occurrence of insect and fungal pests on mon 810 maize was studied. during 2009, exceptionally high maize ear infestation occurred in julianna-major (hungary). from investigation of some thousands of maize ears, the majority of the larval damage originated from helicoverpa armigera larvae, while o. nubilalis larvae contributed signifi ... | 2011 | 26467495 |
identification and differential expression of a sex-peptide receptor in helicoverpa armigera. | sex-pheromone production in the night flying female moth, helicoverpa armigera is under neuroendocrine control due to the timely release of pheromone biosynthesis-activating neuropeptide (pban). males orient to the females by upwind anemotaxis which usually leads to a successful mating. during copulation insect males transfer seminal peptides, produced in male accessory glands (mags) which are implicated in post-mating behavioral changes of the females. these changes include the termination of p ... | 2011 | 21426940 |
galactolipase, phospholipase and triacylglycerol lipase activities in the midgut of six species of lepidopteran larvae feeding on different lipid diets. | galactolipase, phospholipase and triacylglycerol lipase activities were measured from the midgut of six species of lepidopteran larvae, two folivores, epiphyas postvittana (tortricidae) and helicoverpa armigera (noctuidae); two granivores, plodia interpunctella (pyralidae) and ephestia kuehniella (pyrallidae); a presumptive carnivore, galleria mellonella (pyralidae); and a keratinophage, tineola bisselliella (tineidae). galactolipase has not been previously reported in insects. galactolipase and ... | 2011 | 21704634 |
effect of host change on demographic fitness of the parasitoid, trichogramma brassicae. | trichogramma brassicae (bezdenko) is the most important species of trichogramma parasitoids in iran. the cotton bollworm, helicoverpa armigera (hubner) is a polyphagous insect pest that attacks many crops including cotton, maize, soybean, tomato, etc. the bollworm egg is a suitable target for many trichogramma species. factitious hosts such as eggs of the flour moth, anagasta kuehniella (zeller) and cereal moth, sitotroga cerealella (hubner) are used for mass rearing purposes. but a problem that ... | 2010 | 20673197 |
silicon enhances natural enemy attraction and biological control through induced plant defences. | silicon (si) is known to have a role in constitutive plant defence against arthropod pests, and recent work has illustrated involvement in induced plant defences. the present tri-trophic study tested the hypothesis that si increases natural enemy attraction to pest-infested plants and improves biological control. cucumber plants treated with potassium silicate (si+) and untreated control plants (si-) were maintained in separately vented glasshouse compartments. y-tube olfactometer studies showed ... | 2010 | 19737442 |
gene identification and proteomic analysis of the esterases of the cotton bollworm, helicoverpa armigera. | some of the resistance of helicoverpa armigera to conventional insecticides such as organophosphates and synthetic pyrethroids appears to be due to metabolic detoxification by carboxylesterases. to investigate the h. armigera carboxyl/cholinesterases, we created a data set of 39 putative paralogous h. armigera carboxyl/cholinesterase sequences from cdna libraries and other sources. phylogenetic analysis revealed a close relationship between these sequences and 70 carboxyl/cholinesterases from th ... | 2010 | 20005949 |
in vivo inhibition of helicoverpa armigera gut pro-proteinase activation by non-host plant protease inhibitors. | we evaluated 22 different host and non-host plant protease inhibitors (pis) for in vivo inhibition of helicoverpa armigera gut pro- and proteinases, and their biological activity against the pod borer, h. armigera, the most important pest of agriculture and horticultural crops worldwide. in vitro activation of h. armigera gut pro-proteinases (hagpps) in larvae fed on non-host plant pis showed significant in vivo inhibition of hagpps activation in solution as well as in gel assays. the larvae fed ... | 2010 | 20416317 |
modulatory effects of natural curcuminoids on p-glycoprotein atpase of insecticide-resistant pest helicoverpa armigera (lepidopetera: noctüidae). | three major curcuminoids (i, ii and iii) were purified from turmeric and tested for their ability to modulate the function of p-glycoprotein atpase of the insecticide-resistant pest helicoverpa armigera (ha-pgp). the curcumin mixture inhibited the activity of ha-pgp atpase by 80-90% at 100 μm concentration. along with curcuminoids i, ii and iii, it inhibited the verapamil- and ethylparaoxon-stimulated ha-pgp atpase activity. curcuminoid binding was quantitated by quenching the intrinsic trp fluo ... | 2010 | 20821002 |
agrobacterium-mediated transformation in chickpea (cicer arietinum l.) with an insecticidal protein gene: optimisation of different factors. | agrobacterium-mediated transformation in chickpea was developed using strain lba4404 carrying nptii, uida and cryiac genes and transformants selected on murashige and skoog's basal medium supplemented with benzyladenine, kinetin and kanamycin. integration of transgenes was demonstrated using polymerase chain reaction and southern blot hybridization of t0 plants. the expression of cryiac delta endotoxin and gus enzyme was shown by enzyme linked immunosorbent assay and histochemical assay respecti ... | 2010 | 23572977 |
natural history and intragenomic dynamics of the transib transposon hztransib in the cotton bollworm helicoverpa zea. | hztransib, recently identified from helicoverpa zea, represents the first intact and transcriptionally active transib element. its open reading frame was detected in helicoverpa armigera, from which h. zea evolved, and in helicoverpa assulta, the common ancestor of h. zea and h. armigera, but its remaining parts were found only in h. armigera. thirty-nine hztransib insertion sites, all of which are polymorphic, were detected from eight populations of h. zea. out of the 39 insertion sites, 35 wer ... | 2010 | 21166910 |
function of nuclear transport factor 2 and ran in the 20e signal transduction pathway in the cotton bollworm, helicoverpa armigera. | nuclear transport factor 2 and small gtpase ran participate in the nucleo-cytoplasm transport of macromolecules, but their function in the 20-hydroxyecdysone (20e) signal transduction pathway are not well known. | 2010 | 20044931 |
interaction of allium sativum leaf agglutinin with midgut brush border membrane vesicles proteins and its stability in helicoverpa armigera. | allium sativum leaf agglutinin (asal) binds to several proteins in the midgut of helicoverpa armigera and causes toxicity. most of these were glycosylated. six asal-binding proteins were selected for identification. pmf and ms/ms data showed their similarity with midgut aminopeptidase apn2, polycalins and alkaline phosphatase of h. armigera, cadherin-n protein (partial agap009726-pa) of acyrthosiphon pisum, cytochrome p450 (cyp315a1) of manduca sexta and alkaline phosphatase of heliothis viresce ... | 2010 | 21136596 |
effects of transgenic bt cotton on overwintering characteristics and survival of helicoverpa armigera. | the effects of transgenic bt cotton on the overwintering generation of the cotton bollworm, helicoverpa armigera (hübner) (lepidoptera: noctuidae), are unknown. we hypothesized that a bt cotton diet may adversely affect fitness of this generation and examined fresh weight, lipids, glycogens, low-molecular-weight sugars and scps (supercooling points) of pupae, as well as survival of larvae, diapausing pupae and adult emergence in comparison with controls. field and laboratory experiments showed t ... | 2010 | 21034745 |
influence of mutagenesis of bacillus thuringiensis cry1aa toxin on larvicidal activity. | domain iii of bacillus thuringiensis cry δ-endotoxins are considered to be related to the stability of the structure and avoidance of overdigestion by proteases. in this study, some residues of potential chymotrypsin and trypsin sites in domain iii of b. thuringiensis cry1aa were replaced individually with alanine by site-directed mutagenesis, in order to investigate their functional roles. except f574a, all mutants f536a, r543a, f550a, f565a, r566a, f570a, f576a, f583a, and f590a were highly ex ... | 2010 | 21082182 |
[comparison of midgut bacterial community between bt-resistant and sensitive helicoverpa armigera]. | to investigate the midgut bacterial community of sensitive and resistant helicoverpa armigera for the emergence of resistance to bacillus thuringiensis. | 2010 | 20687351 |
baseline sensitivity of lepidopteran corn pests in india to cry1ab insecticidal protein of bacillus thuringiensis. | genetically engineered corn (bt corn) expressing bacillus thuringiensis berliner insecticidal protein cry1ab is a biotechnological option being considered for management of lepidopteran corn pests in india. as a resistance management practice it was essential to determine the sensitivity of multiple populations of the stalk borer chilo partellus (swinhoe), pink borer sesamia inferens (walker) and the cob borer helicoverpa armigera (hübner) to cry1ab protein through bioassays. the insect populati ... | 2010 | 20602522 |
the role of β20-β21 loop structure in insecticidal activity of cry1ac toxin from bacillus thuringiensis. | the β20-β21 loop is a unique structure in the domain iii of bacillus thuringiensis cry proteins. in this study, the role of β20-β21 loop on insecticidal activity of cry1ac toxin was investigated. 10 residues in β20-β21 loop were substituted with alanine using pcr-based site-directed mutagenesis. all mutants were capable of producing diamond-shaped crystal and expressing a protein sized 130 kda. the mutants s581a and i585a enhanced toxicity against helicoverpa armigera larvae dramatically, while ... | 2010 | 20878161 |
helicoverpa armigera single nucleocapsid nucleopolyhedrovirus orf51 is a chab homologous gene involved in budded virus production and dna replication. | the baculovirus chab proteins are conserved in all completely sequenced lepidopteran npvs and are annotated as putative dna binding proteins. here we investigated helicoverpa armigera single nucleocapsid nucleopolyhedrovirus (hearnpv) orf51 (ha51), one of the chab homologues in hearnpv. 5'-race revealed that ha51 is transcribed from a conventional early promoter transcriptional initiator motif (catt) located at 159nt upstream of atg. rt-pcr confirmed that ha51 is an early transcribed gene. to st ... | 2010 | 20951176 |
characteristics of resistance to bacillus thuringiensis toxin cry2ab in a strain of helicoverpa punctigera (lepidoptera: noctuidae) isolated from a field population. | in 1996, the australian cotton industry adopted ingard that expresses the bacillus thuringiensis (bt) toxin gene cry1ac and was planted at a cap of 30%. in 2004-2005, bollgard ii, which expresses cry1ac and cry2ab, replaced ingard in australia, and subsequently has made up >80% of the area planted to cotton, gossypium hirsutum l. the australian target species helicoverpa armigera (hübner) and helicoverpa punctigera (wallengren) are innately moderately tolerant to bt toxins, but the absence of a ... | 2010 | 21309238 |
emergence of minor pests becoming major pests in ge cotton in china: what are the reasons? what are the alternatives practices to this change of status? | a recent study in china by lu et al. ( 1) shows that populations of an occasional cotton pest, mirid bugs (heteroptera: miridae), increased following the introduction of genetically engineered (ge) cotton plants. the ge cotton produces a delta-endotoxin from the bacteria bacillus thuringiensis (bt) to control the cotton bollworm. before the introduction of bt cotton in china, mirid bugs were usually controlled by broad-spectrum pesticide sprays targeted against the cotton bollworm, helicoverpa a ... | 2010 | 21844676 |
cotton plants expressing cyp6ae14 double-stranded rna show enhanced resistance to bollworms. | rna interference (rnai) plays an important role in regulating gene expression in eukaryotes. previously, we generated arabidopsis and tobacco plants expressing double-stranded rna (dsrna) targeting a cotton bollworm (helicoverpa armigera) p450 gene, cyp6ae14. bollworms fed on transgenic dscyp6ae14 plants showed suppressed cyp6ae14 expression and reduced growth on gossypol-containing diet (mao et al., in nat biotechnol 25: 1307-1313, 2007). here we report generation and analysis of dsrna-expressi ... | 2010 | 20953975 |
developmental penalties associated with inducible tolerance in helicoverpa armigera to insecticidal toxins from bacillus thuringiensis. | exposure of insect larvae to sublethal concentrations of crystal toxins from the soil bacterium bacillus thuringiensis (bt toxins) causes the induction of immune and metabolic responses that can be transmitted to offspring by epigenetic inheritance mechanisms. given that the elevated immune status carries significant developmental penalties, we wanted to establish the relationships between immune induction, tolerance to the toxin and developmental penalties. a laboratory culture of helicoverpa a ... | 2010 | 21169448 |
using coi gene sequence to barcode two morphologically alike species: the cotton bollworm and the oriental tobacco budworm (lepidoptera: noctuidae). | due to limited morphological difference, the two closely related sister species, the cotton bollworm, helicoverpa armigera (hübner) and the oriental tobacco budworm, h. assulta (guenée) (lepidoptera: noctuidae), are very difficult to distinguish, especially at the larvae stage. recently, dna sequence has been widely used as a bio-barcode for species identification. in this study, we attempted to distinguish h. armigera and h. assulta using the mitochondrial cytochrome c oxidase subunit i gene (c ... | 2010 | 21181271 |
vip3aa tolerance response of helicoverpa armigera populations from a cry1ac cotton planting region. | transgenic cotton, gossypium hirsutum l., that expresses the bacillus thuringiensis (bt) cry1ac toxin, holds great promise in controlling target insect pests. evolution of resistance by target pests is the primary threat to the continued efficacy of bt cotton. to thwart pest resistance evolution, a transgenic cotton culitvar that produces two different bt toxins, cry1ac and vip3a genes, was proposed as a successor of cry1ac cotton. this article reports on levels of vip3aa tolerance in helicoverp ... | 2010 | 21309241 |
gene-silencing reveals the functional significance of pheromone biosynthesis activating neuropeptide receptor (pban-r) in a male moth. | the role of pheromone biosynthesis activating neuropeptide (pban) in the regulation of pheromone biosynthesis of several female moth species is well elucidated, but its role in the males has been a mystery for over two decades since its discovery from both male and female central nervous systems. in previous studies we have identified the presence of the gene transcript for the pban-g-protein coupled receptor (pban-r) in helicoverpa armigera male hair-pencil-aedaegus complexes (male complexes), ... | 2010 | 20837549 |
characterizing indirect prey-quality mediated effects of a bt crop on predatory larvae of the green lacewing, chrysoperla carnea. | there is increasing evidence that insecticidal transgenic crops can indirectly cause detrimental effects on arthropod predators or parasitoids when they prey on or parasitize sublethally affected herbivores. our studies revealed that chrysoperla carnea is negatively affected when fed bt-susceptible but not cry1ac-resistant helicoverpa armigera larvae that had fed bt-transgenic cotton expressing cry1ac. this despite the fact that the predators ingested 3.5 times more cry1ac when consuming the res ... | 2010 | 20619267 |
conjugative transfer of insecticidal plasmid pht73 from bacillus thuringiensis to b. anthracis and compatibility of this plasmid with pxo1 and pxo2. | bacillus anthracis, the etiologic agent of anthrax, is genetically close to and commonly shares a giant gene pool with b. cereus and b. thuringiensis. in view of the human pathogenicity and the long persistence in the environment of b. anthracis, there is growing concern about the effects of genetic exchange with b. anthracis on public health. in this work, we demonstrate that an insecticidal plasmid, pht73, from b. thuringiensis strain kt0 could be efficiently transferred into two attenuated b. ... | 2010 | 19948871 |
sequencing and characterization of six cdnas putatively encoding three pairs of pheromone receptors in two sibling species, helicoverpa armigera and helicoverpa assulta. | pheromone receptors (prs) on male antennae mediate specific and sensitive detection of sex pheromone components in lepidopterans. in this study, we identified and sequenced six putative cdnas encoding prs from sibling species, namely harmor1, harmor2 and harmor3 in helicoverpa armigera and hassor1, hassor2 and hassor3 in helicoverpa assulta, which appeared to be orthologs of heliothis virescens putative pr genes hvor13, hvor11 and hvor16, respectively. expression patterns of the six pr genes wer ... | 2010 | 19962987 |
characterisation and expression of a novel holotype crystal protein gene, cry56aa1, from bacillus thuringiensis strain ywc2-8. | bacillus thuringiensis isolate ywc2-8, from soil in sichuan basin in western china, contains a spherical crystal harbouring two insecticidal crystal proteins with masses of 70 kda and 130 kda. a novel cry-type gene, encoding a 664 amino acid protein with 34% homology to cry29aa1, was found and cloned from this strain. this gene belongs to a novel holotype cry and is designated as cry56aa1. it was expressed in e. coli. insecticidal activity assays showed that recombinant cry56aa1 was toxic to bot ... | 2010 | 19838632 |
regulation of the seasonal population patterns of helicoverpa armigera moths by bt cotton planting. | transgenic cotton expressing the bacillus thuringiensis (bt) cry1ac toxin has been commercially cultivated in china since 1997, and by 2000 bt cotton had almost completely replaced non-transgenic cotton cultivars. to evaluate the impact of bt cotton planting on the seasonal population patterns of cotton bollworm, helicoverpa armigera, the dynamics of h. armigera moths were monitored with light traps from four locations (xiajin, linqing and dingtao of shandong province; guantao of hebei province) ... | 2010 | 19847665 |
subcellular localization and live-cell imaging of the helicoverpa armigera stunt virus replicase in mammalian and spodoptera frugiperda cells. | whilst their structure has been well studied, there is little information on the replication biology of tetraviruses because of the lack of suitable tissue-culture cell lines that support virus replication. in this study, the potential site of helicoverpa armigera stunt virus replication was investigated by transient expression of the replicase protein fused to enhanced green fluorescent protein (egfp) in mammalian and insect cells. when egfp was present at the c terminus of the protein, fluores ... | 2010 | 20107015 |
identification of protein-protein interactions of the occlusion-derived virus-associated proteins of helicoverpa armigera nucleopolyhedrovirus. | the purpose of this study was to identify protein-protein interactions among the components of the occlusion-derived virus (odv) of helicoverpa armigera nucleopolyhedrovirus (hearnpv), a group ii alphabaculovirus in the family baculoviridae. to achieve this, 39 selected genes of potential odv structural proteins were cloned and expressed in the gal4 yeast two-hybrid (y2h) system. the direct-cross y2h assays identified 22 interactions comprising 13 binary interactions [ha9-odv-ec43, odv-e56-38k, ... | 2010 | 19906939 |
immune responses of helicoverpa armigera to different kinds of pathogens. | insects react against pathogens through innate immunity. the cotton bollworm helicoverpa armigera (h. armigera) is an important defoliator and an extremely destructive pest insect of many crops. the elucidation of the mechanism of the immune response of h. armigera to various pathogens can provide a theoretical basis for new approaches to biologically control this pest. | 2010 | 20196874 |
helicoverpa armigera cadherin fragment enhances cry1ac insecticidal activity by facilitating toxin-oligomer formation. | the interaction between bacillus thuringiensis insecticidal crystal protein cry1a and cadherin receptors in lepidopteran insects induces toxin oligomerization, which is essential for membrane insertion and mediates cry1a toxicity. it has been reported that manduca sexta cadherin fragment cr12-mped and anopheles gambiae cadherin fragment cr11-mped enhance the insecticidal activity of cry1ab and cry4ba to certain lepidopteran and dipteran larvae species, respectively. this study reports that a hel ... | 2010 | 19652967 |
genetically pyramiding protease-inhibitor genes for dual broad-spectrum resistance against insect and phytopathogens in transgenic tobacco. | protease inhibitors provide a promising means of engineering plant resistance against attack by insects and pathogens. sporamin (trypsin inhibitor) from sweet potato and cecpi (phytocystatin) from taro were stacked in a binary vector, using pmspoa (a modified sporamin promoter) to drive both genes. transgenic tobacco lines of t0 and t1 generation with varied inhibitory activity against trypsin and papain showed resistance to both insects and phytopathogens. larvae of helicoverpa armigera that in ... | 2010 | 20055959 |
antisera-mediated in vivo reduction of cry1ac toxicity in helicoverpa armigera. | a functional assessment of bacillus thuringiensis (bt) toxin receptors in the midgut of lepidopteran insects will facilitate understanding of the toxin mode of action and provide effective strategies to counter the development of resistance. in this study, we produced anti-aminopeptidase (apn) and anti-cadherin sera with purified cry1ac toxin-binding apn or cadherin fragments from heliocoverpa armigera. antisera were evaluated for their effects on cry1ac toxicity through bioassays. our results i ... | 2010 | 20035762 |
diverse cadherin mutations conferring resistance to bacillus thuringiensis toxin cry1ac in helicoverpa armigera. | transgenic cotton expressing bacillus thuringiensis (bt) toxins has been widely adopted to control some key lepidopteran pests including the bollworm helicoverpa armigera. evolution of resistance to bt cotton by target pests is a major threat to the continued success of bt cotton. previous results revealed 3 null alleles (r1-r3) of a cadherin gene (ha_btr) conferring cry1ac resistance in h. armigera. an f(1) screen of 123 single-pair families was conducted between a cry1ac-resistant strain (the ... | 2010 | 20079435 |
inheritance of cry1ac resistance and associated biological traits in the cotton bollworm, helicoverpa armigera (lepidoptera: noctuidae). | the analysis of reciprocal genetic crosses between resistant helicoverpa armigera strain (bh-r) (227.9-fold) with susceptible vadodara (va-s) strain showed dominance (h) of 0.65-0.89 and degree of dominance (d) of 0.299-0.782 suggesting cry1ac resistance as a semi-dominant trait. the d and h values of f(1) hybrids of female resistant parent were higher than female susceptible parent, showing maternally enhanced dominance of cry1ac resistance. the progeny of f(2) crosses, backcrosses of f(1) hybr ... | 2010 | 20097203 |
partial functional rescue of helicoverpa armigera single nucleocapsid nucleopolyhedrovirus infectivity by replacement of f protein with gp64 from autographa californica multicapsid nucleopolyhedrovirus. | two distinct envelope fusion proteins (efps) (gp64 and f) have been identified in members of the baculoviridae family of viruses. f proteins are found in group ii nucleopolyhedroviruses (npvs) of alphabaculoviruses and in beta- and deltabaculoviruses, while gp64 occurs only in group i npvs of alphabaculoviruses. it was proposed that an ancestral baculovirus acquired the gp64 gene that conferred a selective advantage and allowed it to evolve into group i npvs. the f protein is a functional analog ... | 2010 | 20739531 |
dose dependency of time to death in single and mixed infections with a wildtype and egt deletion strain of helicoverpa armigera nucleopolyhedrovirus. | recombinant insect nucleopolyhedroviruses lacking the egt gene generally kill their hosts faster than wild-type strains, but the response of insects to mixtures of virus genotypes is less well known. here, we compared the survival time, lethal dose and occlusion body yield in third instar larvae of helicoverpa armigera (hübner) after challenge with wild-type h. armigera snpv (hasnpv-wt), a strain with a deletion of the egt gene, hasnpv-lm2, and a 1:1 mixture of these two virus strains. a range o ... | 2010 | 20123106 |
inactivation of baculovirus by isoflavonoids on chickpea (cicer arietinum) leaf surfaces reduces the efficacy of nucleopolyhedrovirus against helicoverpa armigera. | biological pesticides based on nucleopolyhedroviruses (npvs) can provide an effective and environmentally benign alternative to synthetic chemicals. on some crops, however, the efficacy and persistence of npvs is known to be reduced by plant specific factors. the present study investigated the efficacy of helicoverpa armigera npv (hearnpv) for control of h. armigera larvae, and showed that chickpea reduced the infectivity of virus occlusion bodies (obs) exposed to the leaf surface of chickpea fo ... | 2010 | 20145980 |
characterization of a cry1ac toxin-binding alkaline phosphatase in the midgut from helicoverpa armigera (hübner) larvae. | midgut membrane-bound alkaline phosphatases (malp) tethered to the brush border membrane surface by a glycosylphosphatidylinositol (gpi) anchor have been proposed as crucial for cry1ac intoxication. in the present work, two full-length cdnas-encoding alkaline phosphatases in the midgut of helicoverpa armigera larvae were cloned and named haalp1 (genbank accession no. eu729322) and haalp2 (genbank accession no. eu729323), respectively. these two clones displayed high identity (above 94%) at the a ... | 2010 | 20170658 |
modulation of transcriptome and metabolome of tobacco by arabidopsis transcription factor, atmyb12, leads to insect resistance. | flavonoids synthesized by the phenylpropanoid pathway participate in myriad physiological and biochemical processes in plants. due to the diversity of secondary transformations and the complexity of the regulation of branched pathways, single gene strategies have not been very successful in enhancing the accumulation of targeted molecules. we have expressed an arabidopsis (arabidopsis thaliana) transcription factor, atmyb12, in tobacco (nicotiana tabacum), which resulted in enhanced expression o ... | 2010 | 20190095 |
characterization of bacillus thuringiensis isolates and their differential toxicity against helicoverpa armigera populations. | bacillus thuringiensis isolates were characterized in rhizospheric cotton soils by using acetate selection process from eight different locations in south india. the fact that b. thuringiensis indices were higher in proportion in soil samples taken from tamil nadu and karnataka than from andhra pradesh, indicates the abundance of b. thuringiensis populations in the cotton rhizosphere. biochemical typing of the isolates designated eight local isolates (btng13, btco1, bthyb7, btam2, btrm5, btwr3, ... | 2010 | 21077117 |
host plant flowering increases both adult oviposition preference and larval performance of a generalist herbivore. | most adult lepidoptera feed on nectar, whereas caterpillars consume mainly structural tissue such as leaves, stems, flowers, and/or fruits. this may result in behavioral trade-offs in which search time for high-quality oviposition sites suitable for larval food is restricted by adult foraging needs. here we report on the preference for and performance on flowering and nonflowering host plants of the generalist herbivore helicoverpa armigera to explore whether there are such behavioral trade-offs ... | 2010 | 20388287 |
mamestra brassicae nucleopolyhedrovirus infection and enhancing effect of proteins derived from xestia c-nigrum granulovirus in larvae of mamestra brassicae and helicoverpa armigera (lepidoptera: noctuidae) on cabbage. | the insecticidal effect of mamestra brassicae nucleopolyhedrovirus (mabrnpv) t5 against mamestra brassicae (l.) and helicoverpa armnigera (hiibner) (lepidoptera: noctuidae), important pests of various vegetables and ornamental crops in japan as well as many other countries, and the enhancing activity of proteins derived from occlusion bodies of xestia c-nigrum granulovirus (xecngv) a-4, which was named gvps, on the infectivity of mabrnpv were evaluated in a bioassay with second-instar larvae fed ... | 2010 | 20429436 |
why do f1 screens estimate higher frequencies of cry2ab resistance in helicoverpa armigera (lepidoptera: noctuidae) than do f2 screens? | f2 and f1 tests to detect resistance to cry2ab in helicoverpa armigera (hübner) (lepidoptera: noctuidae) were performed during the 2007-2008 summer. f2 tests indicated a resistance frequency of 0.006, which is similar to the published resistance frequencies for this species during the summers spanning 2002-2006. in contrast f1 tests indicated a resistance frequency of 0.033. thus, f1 tests isolated cry2ab resistance alleles almost six-fold more frequently than the f2 method. a discrepancy might ... | 2010 | 20429464 |
enhancing cry1ac toxicity by expression of the helicoverpa armigera cadherin fragment in bacillus thuringiensis. | insect cadherin proteins localized in the midgut epithelium were identified as receptors for bacillus thuringiensis insecticidal crystal proteins (cry toxins). these cadherins facilitated toxin monomer oligomerization and mediated oligomer binding to secondary receptors. it has been reported that manduca sexta, helicoverpa armigera, anopheles gambiae and diabrotica virgifera cadherin toxin binding regions function as synergists for cry1a, cry4ba and cry3a toxicity against target insects. in the ... | 2010 | 20438837 |
establishment of a cell line from chrysodeixis chalcites permissive for chrysodeixis chalcites and trichoplusia ni nucleopolyhedrovirus. | a new cell line was established from the embryos of the insect chrysodeixis chalcites (lepidoptera, noctuidae, plusiinae). the cell line contains several morphologically different cell types and was distinguished from three other lepidopteran cell lines propagated in the laboratory by dna amplification fingerprinting. the cultured cells, which we officially named wu-cce-1 cells, were permissive for infection by c. chalcites nucleopolyhedrovirus (chchnpv) and large numbers of occlusion bodies wer ... | 2010 | 20471390 |
cloning and characterization of truncated cry1ab gene from a new indigenous isolate of bacillus thuringiensis. | the insecticidal crystal protein(s) encoded by cry gene(s) of bacillus thuringiensis (bt) have been used for insect control both as biopesticides and in transgenic plants. a new 3'-truncated cry1ab gene was cloned from an indigenous isolate of bt, a19-31. nucleotide sequencing and homology search revealed that the deduced amino acid sequence of cry1ab toxin of bt strain a19-31 had a variation of two amino acid residues with the holotype sequence, cry1ab1. expression of the 3'-truncated cry1ab ge ... | 2010 | 20480206 |
induction of a gloverin-like antimicrobial polypeptide in the sugarcane borer diatraea saccharalis challenged by septic injury. | diatraea saccharalis (fabricius, 1794) (lepidoptera: crambidae) is an important pest for brazilian sugarcane. in the present study, we detected two distinct spots in hemolymph from septic injured larvae (hds1 and hds2), which are separated by 2de gel electrophoresis. both spots were subjected to in-gel tryptic digestion and maldi-tof/tof analysis, which revealed the sequence vfgtlgsddsglfgk present in both hds1 and hds2. this sequence had homology and 80% identity with specific lepidoptera antim ... | 2010 | 20490430 |
interaction of recombinant canpis with helicoverpa armigera gut proteases reveals their processing patterns, stability and efficiency. | six diverse representative capsicum annuum (common name: hot pepper; solanaceae) protease inhibitor genes, viz canpi-5, -7, -13, -15, -19, and 22 comprising 1-4 inhibitory repeat domains (irds), were cloned and expressed in pichia pastoris. the recombinant proteins were evaluated for their interactions with bovine trypsin, chymotrypsin, and helicoverpa armigera gut proteases (hgp) using electrophoretic (native and denaturing) and mass spectrometric (maldi-tof-ms in combination with intensity fad ... | 2010 | 20517884 |
selection experiments to assess fitness costs associated with cry2ab resistance in helicoverpa armigera (lepidoptera: noctuidae). | population cage experiments were employed to detect variability in fitness among cry2ab resistant and cry2ab susceptible genotypes of helicoverpa armigera (hübner) (lepidoptera: noctuidae). in two experiments, reciprocal crosses between a cry2ab resistant colony (sp15) and a susceptible colony (gr) established populations where the frequency of the allele that conferred resistance was 0.5. experimental populations were then maintained without exposure to cry toxins. at the f2 generation and on l ... | 2010 | 20568630 |
evidence of field-evolved resistance to cry1ac-expressing bt cotton in helicoverpa armigera (lepidoptera: noctuidae) in northern china. | evolution of resistance threatens the continued success of transgenic crops expressing insecticidal proteins. one of the key factors for successful resistance management is the timely implementation of monitoring programmes to detect early changes of resistance allele frequency in field populations. f(1)/f(2) screen, dose-response bioassays and field survey were used to monitor resistance to the cry1ac-expressing cotton in a field population of helicoverpa armigera (hübner), the primary target o ... | 2010 | 19764057 |
proteomic analysis of novel cry1ac binding proteins in helicoverpa armigera (hübner). | aminopeptidase n (apn) and cadherin-like proteins have been previously identified as cry1ac-binding proteins in helicoverpa armigera (hübner). in this study, a proteomic approach was used to identify novel cry1ac-binding proteins in h. armigera. brush border membrane vesicles (bbmv) of h. armigera were extracted and separated by two-dimensional gel electrophoresis (2-de). cry1ac-binding proteins were detected using antisera against cry1ac. peptide mass fingerprinting (pmf) was used to identify c ... | 2010 | 19847794 |
partial purification and characterization of helicoverpa armigera (lepidoptera: noctuidae) active aminopeptidase secreted in midgut. | we report the partial purification to apparent homogeneity of a soluble aminopeptidase (ec 3.4.11.1) from midgut of helicoverpa armigera larvae, which preferentially degraded leucine p-nitroanilide (lpna). after midgut isolation, extraction and precipitation of soluble proteins with acetone, proteins were purified in two consecutive steps including gel filtration and ion-exchange chromatographies. aminopeptidase activity was increased 8.95 fold after gel filtration chromatography. the purified e ... | 2010 | 19913106 |
genetic variation among helicoverpa armigera populations as assessed by microsatellites: a cautionary tale about accurate allele scoring. | the existence of genetic differences among australian populations of the pest moth helicoverpa armigera based on microsatellite markers is contentious. to resolve this issue, we analyzed microsatellite variation in moth samples from multiple locations simultaneously in two laboratories that have previously reported contrasting patterns. alleles and allele numbers detected in the laboratories differed, as did the genetic differences found between the samples. the automated scoring system used in ... | 2010 | 20003572 |
a comparison of alternative plant mixes for conservation bio-control by native beneficial arthropods in vegetable cropping systems in queensland australia. | cucurbit crops host a range of serious sap-sucking insect pests, including silverleaf whitefly (slw) and aphids, which potentially represent considerable risk to the australian horticulture industry. these pests are extremely polyphagous with a wide host range. chemical control is made difficult due to resistance and pollution, and other side-effects are associated with insecticide use. consequently, there is much interest in maximising the role of biological control in the management of these s ... | 2010 | 19323854 |
downregulation of a chitin deacetylase-like protein in response to baculovirus infection and its application for improving baculovirus infectivity. | several expressed sequence tags (ests) with homology to chitin deacetylase-like protein (cda) were selected from a group of helicoverpa armigera genes whose expression changed after infection with h. armigera single nucleopolyhedrovirus (hearnpv). some of these ests coded for a midgut protein containing a chitin deacetylase domain (cdad). the expressed protein, hacda5a, did not show chitin deacetylase activity, but it showed a strong affinity for binding to chitin. sequence analysis showed the l ... | 2010 | 20032185 |
binding site alteration is responsible for field-isolated resistance to bacillus thuringiensis cry2a insecticidal proteins in two helicoverpa species. | evolution of resistance by target pests is the main threat to the long-term efficacy of crops expressing bacillus thuringiensis (bt) insecticidal proteins. cry2 proteins play a pivotal role in current bt spray formulations and transgenic crops and they complement cry1a proteins because of their different mode of action. their presence is critical in the control of those lepidopteran species, such as helicoverpa spp., which are not highly susceptible to cry1a proteins. in australia, a transgenic ... | 2010 | 20376312 |
transmission of wild-type and recombinant hasnpv among larvae of helicoverpa armigera (lepidoptera: noctuidae) on cotton. | horizontal transmission of insect viruses is a key factor in their cycling in agro-ecosystems. here we study the transmission of the baculovirus hasnpv among larvae of helicoverpa armigera (hübner) in cotton. transmission of three hasnpv genotypes was studied from larvae infected with a single virus genotype and from larvae infected with two different genotypes. genotypes included a wild-type virus, an ecdysteroid udp-glucosyltransferase (egt) deletion mutant (hasnpv-lm2) with slightly enhanced ... | 2010 | 20388275 |
extensive synteny conservation of holocentric chromosomes in lepidoptera despite high rates of local genome rearrangements. | the recent assembly of the silkworm bombyx mori genome with 432 mb on 28 holocentric chromosomes has become a reference in the genomic analysis of the very diverse order of lepidoptera. we sequenced bacs from two major pests, the noctuid moths helicoverpa armigera and spodoptera frugiperda, corresponding to 15 regions distributed on 11 b. mori chromosomes, each bac/region being anchored by known orthologous gene(s) to analyze syntenic relationships and genome rearrangements among the three speci ... | 2010 | 20388903 |
cry genes profiling and the toxicity of isolates of bacillus thuringiensis from soil samples against american bollworm, helicoverpa armigera. | the aim of this study was to search for bacillus thuringiensis (bt) harbouring cry1a gene which could effectively control cotton pest, american bollworm, helicoverpa armigera. | 2010 | 20738439 |
cotton bollworm resistance to bt transgenic cotton: a case analysis. | cotton bollworm (helicoverpa armigera) is one of the most serious insect pests of cotton. transgenic cotton expressing cry toxins derived from a soil bacterium, bacillus thuringiensis (bt), has been produced to target this pest. bt cotton has been widely planted around the world, and this has resulted in efficient control of bollworm populations with reduced use of synthetic insecticides. however, evolution of resistance by this pest threatens the continued success of bt cotton. to date, no fiel ... | 2010 | 20821292 |
susceptibility of helicoverpa armigera (lepidoptera: noctuidae) to cry1ac and cry2ab2 insecticidal proteins in four countries of the west african cotton belt. | transgenic cotton, gossypium hirsutum l., producing cry1ac and cry2ab2 insecticidal proteins from bacillus thuringiensis (bt) was first planted in burkina faso (west africa) in 2008. here, we provide the first baseline data on susceptibility of helicoverpa armigera (hübner) (lepidoptera: noctuidae) populations collected in west africa (benin, cameroon, nigeria, and chad) to cry1ac and cry2ab2 toxins incorporated separately or in combination in a semisynthetic diet. for populations collected in 2 ... | 2009 | 20069861 |
mass rearing methods and biology of microplitis mediator haliday (hymenoptera: braconidae) in china, a candidate for biological control of helicoverpa armigera (lepidoptera: noctuidae). | 2009 | 20222595 | |
assessing the susceptibility of cruciferous lepidoptera to cry1ba2 and cry1ca4 for future transgenic cruciferous vegetables. | advances in transgenic plants expressing bacillus thuringiensis (bt) insecticidal gene(s) offer a promising alternative to traditional insecticides for control of lepidopteran pests on important cruciferous vegetable crops such as cabbage and cauliflower. a public-private partnership, the collaboration on insect management for brassicas in asia and africa (cimbaa), was formed in 2005 with the goal of developing dual-gene bt cauliflower and cabbage, initially for india, to replace the use of broa ... | 2009 | 20069851 |
homodimeric alkaline phosphatase located at helicoverpa armigera midgut, a putative receptor of cry1ac contains alpha-galnac in terminal glycan structure as interactive epitope. | helicoverpa armigera causes massive yield loss of various crops globally. bacillus thuringiensis coded cry1ac toxin is effective against the pest. through the present investigation, an alkaline phosphatase type putative receptor of the toxin was identified in the target insect gut bbmv. lectin-ligand immunoblot assay detected the presence of alpha-galnac residue at the nonreducing terminal of the glycan structure in the membrane bound haalp protein which mediates the toxin-receptor interaction. | 2009 | 19714811 |
frequency of bt resistance alleles in h. armigera during 2006-2008 in northern china. | helicoverpa armigera is an important lepidopteran pest of cotton in china. from 2002, the frequency of bt resistance alleles and quantitative shifts in larval cry1ac tolerance of field h. armigera population were monitored using bioassays of f(1) and f(2) offspring of isofemale lines from xiajin county of shandong province (an intensive bt cotton planting area) and anci county of hebei province (a multiple-crop system including corn, soybean, peanut, and bt cotton) in northern china. during 2006 ... | 2009 | 19689916 |
frequency of alleles conferring resistance to the bacillus thuringiensis toxins cry1ac and cry2ab in australian populations of helicoverpa punctigera (lepidoptera: noctuidae) from 2002 to 2006. | helicoverpa punctigera and helicoverpa armigera (hübner) (lepidoptera: noctuidae) are important pests of field and horticultural crops in australia. the former is endemic to the continent, whereas the latter is also distributed in africa and asia. although h. armigera rapidly developed resistance to virtually every group of insecticide used against it, there is only one report of resistance to an insecticide in h. punctigera. in 1996 the australian cotton industry adopted ingard, which expresses ... | 2009 | 19449655 |
efficient screening and breeding of bacillus thuringiensis subsp. kurstaki for high toxicity against spodoptera exigua and heliothis armigera. | spodoptera exigua is one of the most renowned agricultural pest insects and relatively insensitive to bacillus thuringiensis subsp. kurstaki strains which are widely used commercial products to control lepidopterans such as heliothis armigera. in the current study, we have developed a new and efficient approach to screen and breed a b. thuringiensis subsp. kurstaki strain exhibiting high toxicity against s. exigua while retaining its high toxicity against h. armigera. uv and diethyl sulfate meth ... | 2009 | 19337765 |
the insect snmp gene family. | snmps are membrane proteins observed to associate with chemosensory neurons in insects; in drosophila melanogaster, snmp1 has been shown to be essential for the detection of the pheromone cis-vaccenyl acetate (cva). snmps are one of three insect gene clades related to the human fatty acid transporter cd36. we previously characterized the cd36 gene family in 4 insect orders that effectively cover the holometabola, or some 80% of known insect species and the 300 million years of evolution since th ... | 2009 | 19364529 |
pban receptor: employment of anti-receptor antibodies for its characterization and for development of a microplate binding assay. | this study describes generation of an anti-pban receptor (pban-r) antiserum and its employment for the characterization of the pk/pban-r(s). the antiserum recognized, in a specific and dose-dependent manner, the presence of pban-r in pheromone gland membrane preparations of three female moths: heliothis peltigera, helicoverpa armigera and spodoptera littoralis. it also reacted specifically with the s. littoralis larval receptor in vivo, most likely by competing with the ligand on the binding sit ... | 2009 | 19482031 |
trichogramma (hymenoptera: trichogrammatidae) ecology in a tropical bt transgenic cotton cropping system: sampling to improve seasonal pest impact estimates in the ord river irrigation area, australia. | trichogramma westwood (hymenoptera: trichogrammatidae) cause high mortality rates in the potentially resistant pest species, helicoverpa armigera (hübner) (lepidoptera: noctuidae), and are considered integral to the resistance management plan for bacillus thuringiensis transgenic cotton, gossypium hirsutum l., production in the ord river irrigation area (oria), western australia. measured as percentage of parasitism, trichogramma activity seems highly variable over time; yet, it contributes sign ... | 2009 | 19610415 |
limited survival of a cry2ab-resistant strain of helicoverpa armigera (lepidoptera: noctuidae) on bollgard ii. | bollgard ii cotton (which expresses two bt insecticidal genes cry1ac/cry2ab) and conventional cotton, grown in the laboratory or field and sampled at different stages, was exposed to helicoverpa armigera (hübner) larvae of three genotypes: homozygous for resistance to cry2ab; homozygous for susceptibility to cry2ab, and heterozygous for resistance. survival of all genotypes was limited on bollgard ii but increased as plants aged. this was particularly the case for homozygous resistant individual ... | 2009 | 19449653 |
effects of spinosad on helicoverpa armigera (lepidoptera: noctuidae) from china: tolerance status, synergism and enzymatic responses. | spinosad is increasingly used in pest management programmes, and resistance to it has been detected in recent years. however, there is no report on the susceptibilities of field populations of helicoverpa armigera (hübner) from china. furthermore, the impact of spinosad on metabolic enzymes in this pest remains unknown. | 2009 | 19533589 |
differential elicitation of proteases and protease inhibitors in two different genotypes of chickpea (cicer arietinum) by salicylic acid and spermine. | elicitation of proteases and protease inhibitors (pis) by salicylic acid (sa) and spermine (spm) was investigated in roots and shoots of two different genotypes of chickpea cultivars iccv10 and l550, which were resistant and susceptible to wilt disease, respectively. sa and spm were found to suppress the elicitation of proteases in the resistant cv, whereas they induce it in susceptible cv. elicitation of new trypsin and chymotrypsin inhibitors was observed in the roots and shoots of resistant c ... | 2009 | 19201507 |
seasonal migration of helicoverpa armigera (lepidoptera: noctuidae) over the bohai sea. | the seasonal migration of the helicoverpa armigera (hübner) (lepidoptera: noctuidae) over the bohai sea was observed with a searchlight trap and an entomological radar located on a small island in the center of the sea, and through a network of light-traps around the bohai region. the h. armigera moths were observed to migrate over the sea at least as early as may and light trapping through a network suggested migration might start as early as april, as soon as the moths had emerged from overwin ... | 2009 | 19253623 |
effects of bacillus thuringiensis toxin cry1ac and cytoplasmic polyhedrosis virus of helicoverpa armigera (hübner) (hacpv) on cotton bollworm (lepidoptera: noctuidae). | in this study, interactions on the mortality and debilitating effects between cry1ac, a toxic protein produced by bacillus thuringiensis (berliner) and hacpv (chinese strain) on first and third instars larvae of helicoverpa armigera were evaluated in laboratory. when first instar was exposed to combination of bt cotton leaf discs containing hacpv (6 x 10(6), 1 x 10(7), and 3 x 10(7) pib ml(-1)) the effect on mortality was additive, when such instar larvae exposed to combination of cry1ac (0.9, 2 ... | 2009 | 19269293 |
efficient constitutive expression of chitinase in the mother cell of bacillus thuringiensis and its potential to enhance the toxicity of cry1ac protoxin. | previous studies revealed that chitinase could enhance the insecticidal activity of bacillus thuringiensis and it has been used in combination with b. thuringiensis widely. however, the expression of b. thuringiensis chitinase is rather low and needs induction by chitin, which limits its field application. it would make sense to constitutively express the chitinase at a sufficiently high level to offer advantages in biological control of pests. in this study, a signal peptide-encoding sequence-d ... | 2009 | 19277644 |
aerosol infectivity of a baculovirus to trichoplusia ni larvae: an alternative larval inoculation strategy for recombinant protein production. | the baculovirus-insect expression system is a popular tool for recombinant protein production. the standard method for infecting insect larvae with recombinant baculovirus for protein production involves either feeding occlusion bodies or injecting budded virus into the cuticle. in this study, we showed that the recombinant autographa californica multiple nucleopolyhedrovirus (acmnpv) at titers >10(8) pfu/ml efficiently infected trichoplusia ni (t. ni) larvae through aerosol inoculation of budde ... | 2009 | 19334290 |
mutation of an aminopeptidase n gene is associated with helicoverpa armigera resistance to bacillus thuringiensis cry1ac toxin. | a cry1ac-resistant strain (bt-r) of helicoverpa armigera, with 2971-fold resistance, was derived by selection with cry1ac toxin for 75 generations. we used cdna-amplified fragment length polymorphism analysis to identify those genes differentially expressed in the cry1ac-resistant and -susceptible strains, which revealed 212 differentially expressed transcripts among 2000 screened cdnas. among these transcript-derived fragments (tdfs), 37 showed some homology to known sequences, including aminop ... | 2009 | 19376227 |
reduction of bacillus thuringiensis cry1ac toxicity against helicoverpa armigera by a soluble toxin-binding cadherin fragment. | a cadherin-like protein has been identified as a putative receptor for bacillus thuringiensis (bt) cry1ac toxin in helicoverpa armigera and plays a key role in bt insecticidal action. in this study, we produced a fragment from this h. armigera cry1ac toxin-binding cadherin that included the predicted toxin-binding region. binding of cry1ac toxin to this cadherin fragment facilitated the formation of a 250-kda toxin oligomer. the cadherin fragment was evaluated for its effect on cry1ac toxin-bind ... | 2009 | 19446559 |
cloning and characterization of two novel crystal protein genes, cry54aa1 and cry30fa1, from bacillus thuringiensis strain btmc28. | bacillus thuringiensis strain btmc28 was isolated from the soil sample in china. two novel crystal protein genes were found by using the pcr-rflp method. moreover, the full-length sequences of two novel genes were obtained by a single oligonucleotide nested (son)-pcr upstream and downstream strategy. sequence analysis revealed that one gene encoded a polypeptide of 673 amino acid residues with a molecular mass of 76.3 kda, 38% identical to cry10aa, and the other encoded a polypeptide of 687 amin ... | 2009 | 19280260 |
overexpression of a weed (solanum americanum) proteinase inhibitor in transgenic tobacco results in increased glandular trichome density and enhanced resistance to helicoverpa armigera and spodoptera litura. | in this study we produced transgenic tobacco plants by overexpressing a serine proteinase inhibitor gene, sapin2a, from the american black nightshade solanum americanum under the control of the camv 35s promoter using agrobacterium tumefaciens-mediated transformation. sapin2a was properly transcribed and translated as indicated by northern blot and western blot analyses. functional integrity of sapin2a in transgenic plants was confirmed by proteinase inhibitory activity assay. bioassays for inse ... | 2009 | 19468345 |