| effectiveness of bacillus thuringiensis-transgenic chickpeas and the entomopathogenic fungus metarhizium anisopliae in controlling helicoverpa armigera (lepidoptera: noctuidae). | the use of genetically modified (bt) crops expressing lepidopteran-specific cry proteins derived from the soil bacterium bacillus thuringiensis is an effective method to control the polyphagous pest helicoverpa armigera. as h. armigera potentially develops resistance to cry proteins, bt crops should be regarded as one tool in integrated pest management. therefore, they should be compatible with biological control. bioassays were conducted to understand the interactions between a cry2aa-expressin ... | 2008 | 18487396 |
| diversity of aminopeptidases, derived from four lepidopteran gene duplications, and polycalins expressed in the midgut of helicoverpa armigera: identification of proteins binding the delta-endotoxin, cry1ac of bacillus thuringiensis. | helicoverpa armigera midgut proteins that bind the bacillus thuringiensis (bt) delta-endotoxin cry1ac were purified by affinity chromatography. sds-page showed that several proteins were eluted with n-acetylgalactosamine and no further proteins were detected after elution with urea. tandem mass spectral data for tryptic peptides initially indicated that the proteins resembled aminopeptidases (apns) from other lepidopterans and cdna sequences for seven apns were isolated from h. armigera through ... | 2008 | 18549954 |
| unusually high frequency of genes encoding vegetative insecticidal proteins in an australian bacillus thuringiensis collection. | of 188 australian bacillus thuringiensis strains screened for genes encoding soluble insecticidal proteins by polymerase chain reaction/restriction-length fragment polymorphism (rflp) analysis, 87% showed the presence of such genes. although 135 isolates (72%) produced an rflp pattern identical to that expected for vip3a genes, 29 isolates possessed a novel vip-like gene. the novel vip-like gene was cloned from b. thuringiensis isolate c81, and sequence analysis demonstrated that it was 94% iden ... | 2008 | 18592309 |
| use of a cry1ac-resistant line of helicoverpa armigera (lepidoptera: noctuidae) to detect novel insecticidal toxin genes in bacillus thuringiensis. | this paper describes a screening strategy incorporating resistant insect lines for discovery of new bacillus thuringiensis toxins against a background of known genes that would normally mask the activity of additional genes and the application of that strategy. a line of helicoverpa armigera with resistance to cry1ac (line isoc) was used to screen cry1ac-expressing strains of b. thuringiensis for additional toxins with activity against h. armigera. using this approach, a number of cry1ac-produci ... | 2008 | 18592310 |
| isolations of cry2ab resistance in australian populations of helicoverpa armigera (lepidoptera: noctuidae) are allelic. | alleles conferring resistance to cry2ab toxin occur at a frequency of 0.0033 in australian populations of helicoverpa armigera (hübner) (lepidoptera: noctuidae), and it is evident that detectable levels of resistance predated the introduction of transgenic cotton expressing this toxin. from 2002 until 2006, 10 such resistant alleles were scored. here, we examine colonies established from five of the 10 isolates by using complementation tests to determine their genetic relationships. the results ... | 2008 | 18613594 |
| resistance allele frequency to bt cotton in field populations of helicoverpa armigera (lepidoptera: noctuidae) in china. | resistance evolution in target insects to bacillus thurningiensis (bt) cotton, gossypium hirsutum l., is a main threat to bt cotton technology. an increasing trend of population density of helicoverpa armigera (hübner) (lepidoptera: noctuidae) has been observed since 2001 in qiuxian county (hebei, china), where bt cotton has been planted dominantly since 1998. this region was selected in 2006 and 2007 for estimating frequency of gene alleles conferring resistance to bt cotton by screening the f1 ... | 2008 | 18613597 |
| up-regulation of lysozyme gene expression during metamorphosis and immune challenge of the cotton bollworm, helicoverpa armigera. | lysozymes act as crucial bacteriolytic enzymes in insect immune system by hydrolyzing the beta (1-->4) bonds between n-acetylglucosamine and n-acetylmuramic acid in the peptidoglycan of prokaryotic cell walls. we have isolated and characterized a helicoverpa armigera cdna encoding an insect lysozyme named halyz. we amplified a fragment by pcr, using degenerate primers derived from the conservative amino acid sequences for performing 5' and 3' race. the full-length cdna was 661 base pairs. the th ... | 2009 | 18615707 |
| radioimmunoassay analysis of baculovirus granulins and polyhedrins. | granulin and polyhedrin proteins were purified by preparative sodium dodecyl sulfate (sds)-polyacrylamide gel electrophoresis from the baculoviruses autographa californica, rachiplusia ou, heliothis zea, heliothis armigera, trichoplusia ni, and spodoptera frugiperda. antisera were raised against autographa californica (ac) polyhedrin and trichoplusia ni (tn) granulin and analyzed for homologous and heterologous immunoreactivity by immunodiffusion and radioimmunoassay (ria). ac polyhedrin and tn ... | 1980 | 18631650 |
| induction of a nonoccluded baculovirus persistently infecting heliothis zea cells by heliothis armigera and trichoplusia ni nuclear polyhedrosis viruses. | a nonoccluded singly enveloped baculovirus (baculovirus x) persistently infects heliothis zea (imc-hz-1) cells in culture. singly enveloped nuclear polyhedrosis viruses from h. zea and heliothis armigera, and multiply enveloped nuclear polyhedrosis viruses from trichoplusia ni, spodoptera frugiperda, and spodoptera littoralis were all found to induce baculovirus x. experiments are reported which use metabolic inhibitors and inactivated inducing virus to show that it is probable that a structural ... | 1981 | 18635066 |
| comparison of sequence diversity in several cytoplasmic polyhedrosis viruses. | sequence homology among several different cytoplasmic polyhedrosis virus (cpv) types and the human reovirus (type 1) was examined by northern blot analysis and s, nuclease analysis, using random-primed cdna probes synthesized from total genomic rna. the results show no homology among the cpv type 1, bombyx mori cpv, type 5, orgyia pseudotsugata cpv, type 8, manduca sexta cpv and the human reovirus (type 1). however, there was significant homology among three type 5 cpvs, o. pseudotsugata cpv, eu ... | 1983 | 18639153 |
| an insecticidal groel protein with chitin binding activity from xenorhabdus nematophila. | xenorhabdus nematophila secretes insecticidal proteins to kill its larval prey. we have isolated an approximately 58-kda groel homolog, secreted in the culture medium through outer membrane vesicles. the protein was orally insecticidal to the major crop pest helicoverpa armigera with an lc50 of approximately 3.6 microg/g diet. for optimal insecticidal activity all three domains of the protein, apical, intermediate, and equatorial, were necessary. the apical domain alone was able to bind to the l ... | 2008 | 18667427 |
| expression of v-cath gene from hearnpv in tobacco confers an antifeedant effect against helicoverpa armigera. | biotechnology solutions for insect control on crops largely depend on the expression of bacillus thuringiensis insecticidal proteins to kill pests. v-cath, a cathepsin l-like cysteine protease from baculoviruses, has been shown to play an essential role in host insect liquefaction. in this study, the v-cath gene from helicoverpa armigera single nucleopolyhedrovirus (hearnpv) was cloned into the pbi121 binary vector under the control of camv35s promoter, and was expressed in tobacco via agrobacte ... | 2008 | 18722486 |
| functional studies of per os infectivity factors of helicoverpa armigera single nucleocapsid nucleopolyhedrovirus. | a combined functional investigation on the four per os infectivity factors (pifs) of helicoverpa armigera single nucleocapsid nucleopolyhedrovirus (hearnpv) was conducted in this study. hearnpv bacmids with deletions of p74 (ha20), pif1 (ha111), pif2 (ha132) and pif3 (ha98) were constructed individually by homologous recombination in escherichia coli cells. repaired bacmids with respective pifs were also constructed. western blot analyses revealed that all four pifs were structural components of ... | 2008 | 18753243 |
| proteomic analysis of the peritrophic matrix from the gut of the caterpillar, helicoverpa armigera. | the peritrophic matrix from the midgut of the caterpillar, helicovera armigera, was solubilized by treatment with anhydrous trifluoromethanesulfonic acid, apparently by depolymerisation of its chitin component. this allowed the efficient extraction of proteins in a technique that may be broadly applicable to the analysis of other structures containing chitin. gel electrophoresis and mass spectrometry of tryptic peptides were used to identify the extracted proteins with gut-expressed cdna sequenc ... | 2008 | 18760362 |
| effects of larval host plants on over-wintering physiological dynamics and survival of the cotton bollworm, helicoverpa armigera (hübner) (lepidoptera: noctuidae). | laboratory colonies of cotton bollworm larvae, helicoverpa armigera, were kept at 20 degrees c under a photoperiod of l:d=10:14 and fed on three host plants (cotton, tobacco, kidney bean) and an artificial diet (control) to determine the dynamic effects of larval host quality on over-wintering physiology and mortality. energy reserves (glycogen and lipid), super-cooling points (scps), low-molecular-weight sugars, temperature, and mortality were monitored from november 2002 to april 2003. lipid c ... | 2009 | 18761347 |
| characterization of the cry1ac17 gene from an indigenous strain of bacillus thuringiensis subsp. kenyae. | an indigenously isolated strain of bacillus thuringiensis subsp. kenyae exhibited toxicity against lepidopteran as well as dipteran insects. the lepidopteran active cry1ac protoxin gene coding sequence of 3.5 kb from this strain was cloned into vector pet28a(+). however, it could not be expressed in commonly used escherichia coli expression hosts, bl21(de3) and bl21(de3)plyss. this gene is classified as cry1ac17 in the b. thuringiensis toxic nomenclature database. the coding sequence of this gen ... | 2008 | 18795364 |
| reproductive biology of two nontarget insect species, aphis gossypii (homoptera: aphididae) and orius sauteri (hemiptera: anthocoridae), on bt and non-bt cotton cultivars. | transgenic bt cotton, engineered to continuously produce activated delta-endotoxins of the soil bacteria bacillus thuringiensis, holds great promise in controlling helicoverpa armigera and other lepidopteran pests. however, it also may impact the invertebrate community, which needs to be clarified. the effects of bt cotton on two nontarget insects, aphis gossypii and orius sauteri, were assessed under semifield and laboratory conditions. mean total duration of nymphal stages of a. gossypii was s ... | 2008 | 18801270 |
| suppression of cotton bollworm in multiple crops in china in areas with bt toxin-containing cotton. | transgenic cotton that has been engineered to produce insecticidal toxins from bacillus thuringiensis (bt) and so to resist the pest cotton bollworm (helicoverpa armigera) has been widely planted in asia. analysis of the population dynamics of h. armigera from 1992 to 2007 in china indicated that a marked decrease in regional outbreaks of this pest in multiple crops was associated with the planting of bt cotton. the study area included six provinces in northern china with an annual total of 3 mi ... | 2008 | 18801998 |
| solubilization, activation, and insecticidal activity of bacillus thuringiensis serovar thompsoni hd542 crystal proteins. | cry15aa protein, produced by bacillus thuringiensis serovar thompsoni hd542 in a crystal together with a 40-kda accompanying protein, is one of a small group of nontypical, less well-studied members of the cry family of insecticidal proteins and may provide an alternative for the more commonly used cry proteins in insect pest management. in this paper, we describe the characterization of the cry15aa and 40-kda protein's biochemical and insecticidal properties and the mode of action. both protein ... | 2008 | 18836017 |
| specific binding of bacillus thuringiensis cry2a insecticidal proteins to a common site in the midgut of helicoverpa species. | for a long time, it has been assumed that the mode of action of cry2a toxins was unique and different from that of other three-domain cry toxins due to their apparent nonspecific and unsaturable binding to an unlimited number of receptors. however, based on the homology of the tertiary structure among three-domain cry toxins, similar modes of action for all of them are expected. to confirm this hypothesis, binding assays were carried out with (125)i-labeled cry2ab. saturation assays showed that ... | 2008 | 18931285 |
| introgression of a disrupted cadherin gene enables susceptible helicoverpa armigera to obtain resistance to bacillus thuringiensis toxin cry1ac. | a disrupted allele (r1) of a cadherin gene (ha_btr) is genetically associated with incompletely recessive resistance to bacillus thuringiensis toxin cry1ac in a cry1ac-selected strain (gybt) of helicoverpa armigera. the r1 allele of ha_btr was introgressed into a susceptible scd strain by crossing the gybt strain to the scd strain, followed by repeated backcrossing to the scd strain and molecular marker assisted family selection. the introgressed strain (designated as scd-r1, carrying homozygous ... | 2009 | 18954492 |
| growth, viral production and metabolism of a helicoverpa zea cell line in serum-free culture. | insect cell cultures have been extensively utilised for means of production for heterologous proteins and biopesticides. spodoptera frugiperda (sf9) and trichoplusia ni (high fivetrade mark) cell lines have been widely used for the production of recombinant proteins, thus metabolism of these cell lines have been investigated thoroughly over recent years. the helicoverpa zea cell line has potential use for the production of a biopesticide, specifically the helicoverpa armigera single-nucleocapsid ... | 2003 | 19002933 |
| relationships among activities of extracellular enzyme production and virulence against helicoverpa armigera in beauveria bassiana. | extracellular enzymes produced by beauveria bassiana, are believed to play a key role in cuticle hydrolysis. enzyme production and pathogenicity has been found to be positively correlated. twenty-eight isolates of b. bassiana, collected from different geographical regions and host ranges were characterized by in vitro extracellular enzyme production and sds-page techniques for discerning biochemical basis for virulence among the different isolates. in vitro analysis of extracellular enzymes like ... | 2009 | 19025880 |
| winged bean chymotrypsin inhibitors retard growth of helicoverpa armigera. | two putative kunitz-type chymotrypsin inhibitor genes (wci2 and wci5) were isolated from winged bean (psophocarpus tetragonolobus (l.) dc). while wci2 has previously been characterized, wci5 represents a new member of the wci family. wci5 was exclusively expressed in winged bean seeds. theoretical translation of both the genes resulted into polypeptides of 207 amino acids with 86% sequence similarity. the polypeptide sequences contain four half-cysteine residues and a well-conserved leu(65)-ser( ... | 2009 | 19059315 |
| resistance of helicoverpa armigera to cry1ac toxin from bacillus thuringiensis is due to improper processing of the protoxin. | the bacterium bacillus thuringiensis produces icps (insecticidal crystal proteins) that are deposited in their spore mother cells. when susceptible lepidopteran larvae ingest these spore mother cells, the icps get solubilized in the alkaline gut environment. of approx. 140 insecticidal proteins described thus far, insecticidal protein cry1ac has been applied extensively as the main ingredient of spray formulation as well as the principal icp introduced into crops as transgene for agricultural cr ... | 2009 | 19146482 |
| using an f(2) screen to monitor frequency of resistance alleles to bt cotton in field populations of helicoverpa armigera (hübner) (lepidoptera: noctuidae). | in an effort to control the most devastating cotton pest, helicoverpa armigera (hübner), in qiuxian county (hebei, china), bt cotton has been planted almost exclusively since 1998 in this area. owing to the high insecticidal selection pressures in this region, monitoring of bt resistance in h. armigera is necessary so that proactive actions can be implemented before field control measures fail. from 2003 to 2005, an f(2) screen was conducted in order to monitor bt resistance in h. armigera popul ... | 2009 | 19165746 |
| modified female calling behaviour in cry1ac-resistant helicoverpa armigera (lepidoptera: noctuidae). | the resistance risk in helicoverpa armigera (hübner) to transgenic cotton that expresses cry1ac from bacillus thuringiensis (bt) has raised concerns about the sustainable deployment of bt cotton. mating behaviour between resistant and susceptible individuals is an important factor that affects resistance evolution of the insect. the female calling behaviours of the cry1ac-resistant strain and its susceptible control were compared in the laboratory to understand the difference in mating biology. | 2009 | 19165761 |
| constitutive expression of a trypsin protease inhibitor confers multiple stress tolerance in transgenic tobacco. | protease inhibitors have been reported to confer insect resistance in transgenic plants, except for a rice protease inhibitor that conferred drought tolerance in transgenic rice plants. we have cloned a protease inhibitor of tobacco that is expressed under treatment with aba, hydrogen peroxide, methyl jasmonate and wounding. the cdna codes for a six-domain serine protease inhibitor with a deduced sequence of 396 amino acids. we have generated transgenic tobacco plants expressing the protease inh ... | 2009 | 19179349 |
| characterization of a c-type lectin from the cotton bollworm, helicoverpa armigera. | c-type lectins can specifically recognize sugars on the surface of microorganisms and cause a series of immune responses to effectively resist pathogenic invasions. in previous work in our laboratory, we obtained a c-type lectin from helicoverpa armigera (ha-lectin). it has two different carbohydrate recognition domains (crds) crd1 and crd2 arranged in tandem. in this study, recombinant crd1 and crd2 were expressed separately in escherichia coli and purified. they have the ability to agglutinate ... | 2009 | 19185587 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| [identification and cloning of vip3a genes from isolates of bacillus thuringiensis and their bioactivity analysis]. | to survey the distribution of vip3a-type genes from isolates of bacillus thuringiensis in china and to clone novel vip3a genes encoding vip3a proteins with high insecticidal activity against lepidopteran insect larvae. | 2009 | 19388273 |
| ultraviolet light-induced oxidative stress: effects on antioxidant response of helicoverpa armigera adults. | ultraviolet (uv) light (blacklight), which emits uv in the range of 320-400 nm, has been used worldwide in light trapping of insect pests. in this article, we test the hypothesis that one of the effects of uv light irradiation is to increase oxidative stress on insects. the effects of uv light irradiation on total antioxidant capacity, malondialdehyde (mda) and protein carbonyl contents and the activities of superoxide dismutase (sod), catalase (cat), peroxidases (pox) and glutathione-s-transfer ... | 2009 | 19418599 |
| [chitinase b from bacillus thuringiensis enhancing potential and its antagonism and insecticidal]. | we studied the characteristics of chitinase b (chib) from bacillus thuringiensis subsp. colmeri 15a3 (bt 15a3) and evaluated its antagonism and insecticidal potential. | 2009 | 19445172 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| genetic variability of the bollworm, helicoverpa armigera, occurring on different host plants. | the bollworm, helicoverpa armigera hübner (lepidoptera: noctuidae) is a polyphagous pest of worldwide occurrence inflicting annual crop damage in india worth us$ 1 billion. in india this insect occurs as a major pest in many economically important crops, including cotton, pigeonpea, chickpea, tomato, okra, and blackgram. understanding the genetic variation among the h. armigera populations occurring on host plants has become essential to understand the variation in their susceptibility to differ ... | 2006 | 19537981 |
| bacillus thuringiensis bel protein enhances the toxicity of cry1ac protein to helicoverpa armigera larvae by degrading insect intestinal mucin. | bacillus thuringiensis has been used as a bioinsecticide to control agricultural insects. bacillus cereus group genomes were found to have a bacillus enhancin-like (bel) gene, encoding a peptide with 20 to 30% identity to viral enhancin protein, which can enhance viral infection by degradation of the peritrophic matrix (pm) of the insect midgut. in this study, the bel gene was found to have an activity similar to that of the viral enhancin gene. a bel knockout mutant was constructed by using a p ... | 2009 | 19542344 |
| 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 |
| cry2ab tolerance response of helicoverpa armigera (lepidoptera: noctuidae) populations from crylac cotton planting region. | helicoverpa armigera (hübner) (lepidoptera: noctuidae) is an important lepidopteran pest of cotton, gossypium hirsutum l., in asia. transgenic cotton expressing the cry1ac gene from bacillus thuringiensis (bt) has been widely planted for control of this pest. for managing the potential risk from resistance evolution in this pest, a new transgenic bt cotton containing cry1ac and cry2ab genes (gene pyramided strategy) was designed as a successor of cry1ac cotton. this article reports on levels of ... | 2009 | 19610441 |
| 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 |
| the expression of a recombinant cry1ac gene with subtilisin-like protease cdep2 gene in acrystalliferous bacillus thuringiensis by red/et homologous recombination. | a novel cdna encoding the subtilisin-like serine protease gene cdep2 was isolated from beauveria bassiana by reverse transcription polymerase chain reaction (rt-pcr). it contained an 1137 bp orf that predicted a protein of 379 amino acids with m = 38863 da and pi = 8.21. in an attempt to improve insecticidal activity, the cdep2 gene and the cry1ac gene from bacillus thuringiensis were co-fused into the vector pht315 as phac-cdep2 plasmid by red/et homologous recombination. the co-fusion gene was ... | 2009 | 19653036 |
| 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 |
| 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 |
| functional analysis of the autographa californica nucleopolyhedrovirus iap1 and iap2. | the autographa californica nucleopolyhedrovirus (acmnpv) contains three apoptosis suppressor genes: p35, iap1 and iap2. acmnpv p35 functions as a pancaspase inhibitor, but the function of iap1 and iap2 has not been entirely resolved. in this paper, we analyze the function of iap1 and iap2 in detail. acmnpv with p35-deletion inhibited the apoptosis of bti-tn-5b1-4 (tn-hi5) cells induced by a helicoverpa armigera single nucleocapsid npv (hearnpv) infection and rescued the replication of hearnpv an ... | 2009 | 19727595 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| a homolog of the vaccinia virus d13l rifampicin resistance gene is in the entomopoxvirus of the parasitic wasp, diachasmimorpha longicaudata. | the parasitic wasp, diachasmimorpha longicaudata (ashmead) (hymenoptera: braconidae), introduces an entomopoxvirus (dlepv) into its caribbean fruit fly host, anastrepha suspensa. (loew) (diptera: tephritidae), during oviposition. dlepv has a 250-300 kb unipartite dsdna genome, that replicates in the cytoplasm of the host's hemocytes, and inhibits the host's encapsulation response. the putative proteins encoded by several dlepv genes are highly homologous with those of poxviruses, while others ap ... | 2008 | 20345294 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| [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 |
| 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 |
| 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 |
| 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 |