| insect resistance to transgenic bt crops: lessons from the laboratory and field. | transgenic crops that produce insecticidal toxins from the bacterium bacillus thuringiensis (bt) grew on >62 million ha worldwide from 1996 to 2002. despite expectations that pests would rapidly evolve resistance to such bt crops, increases in the frequency of resistance caused by exposure to bt crops in the field have not yet been documented. in laboratory and greenhouse tests, however, at least seven resistant laboratory strains of three pests (plutella xylostella [l.], pectinophora gossypiell ... | 2003 | 14503572 |
| a new cell line from the embryonic tissue of helicoverpa armigera hbn. (lepidoptera: noctuidae). | a new cell line from the embryonic tissue of helicoverpa armigera was established and designated as niv-ha-197. it was maintained in tnm-fh medium supplemented with 10% fetal bovine serum. the cell line at passage 20 had a heterogeneous population of cells consisting of mainly epithelial-like cells (70%), followed by fibroblast-like (27%), and multinucleated giant (3%) cells. the chromosome number ranged from 45 to 185. the growth curve at passage 40 showed a fivefold increase in cell number wit ... | 2002 | 12418922 |
| recombinantly expressed isoenzymic aminopeptidases from helicoverpa armigera (american cotton bollworm) midgut display differential interaction with closely related bacillus thuringiensis insecticidal proteins. | several investigators have independently identified membrane-associated aminopeptidases in the midgut of insect larvae as the initial interacting ligand to the insecticidal crystal proteins of bacillus thuringiensis. though several isoenzymes of aminopeptidases have been identified from the midgut of an insect and their corresponding cdna cloned, only one of the isoform has been expressed heterologously and studied for its binding to cry toxins. here we report the cloning and expression of two a ... | 2003 | 12441000 |
| [the characteristics of bacillus thuringiensis strain ybt833 and its transformants that containing different icp genes]. | four different transformants were selected by transferring cry1c into bacillus thuringiensis strain ybt833. southern blot and plasmid profiles results all proved that cry1c was transferred into strain ybt833. however, it was found by pcr analysis that transformant ybt833-1 kept all indigenous icp(insecticidal crystal protein) genes of strain ybt833 while transformant ybt833-2 lost cry1ab, and transformant ybt833-3 lost all icp genes. sds-page showed that transformants of ybt833-1, ybt833-2 and y ... | 2000 | 11132501 |
| open reading frame 122 of helicoverpa armigera single nucleocapsid nucleopolyhedrovirus encodes a novel structural protein of occlusion-derived virions. | helicoverpa armigera single nucleocapsid nucleopolyhedrovirus (hasnpv) and its closely related variant h. zea snpv (hzsnpv) contain 20 open reading frames (orfs) unique among baculoviruses. in this report, the function of hasnpv orf 122 (ha122) is investigated. ha122 was transcribed as a polyadenylated transcript from 8 h post-infection in infected h. armigera insect cells. 5'race analysis indicated that ha122 transcription starts predominantly in the consensus major late transcription initiatio ... | 2003 | 12533707 |
| [identification of cry-type genes of 31 bacillus thuringiensis isolates and analysis of their expression product]. | in this study, cry-type gene of 31 isolates of bt had been identified using pcr-rflp identification system, and sds-page analysis and bioassay had been performed. 25 strains containing cry1 type gene express 130-150 kd protein and 16 of them contain cry1i gene, which codes 80 kd protein and is larvicidal to both lepidopteran and coleopteran species. 15 strains contain both cry1 and cry2 type gene; 10 strains contain unknown cry-type gene; 6 strains don't contain seven identified cry-type gene. r ... | 2000 | 12548957 |
| [molecular cloning of enhancin gene from helicoverpa armigera granulosis virus and its expression in e. coli]. | in order to provide recombinant enhancin for studying its mechanism of increasing the mortality of larvae infected by hanpv and creating new insecticide, enhancin gene from helicoverpa armigera granulosis virus was amplified by pcr technique. 2.7 kb fragment of enhancin gene was cloned into ecori/xbai site of plasmid pbluescript ks. sequence analysis revealed that enhancin gene was similar with that reported in the literature except eight nucleotides and five amino acids. thereby enhancin gene w ... | 2000 | 12548958 |
| [expression and synergism of two cry insecticidal protein genes in pseudomonas fluorescens]. | several engineered pseudomonas fluorescens(pf) strains were constructed mainly based on a pseudomonas plasmid pjms6 alpha-lac and two insecticidal crystal protein genes of bacillus thuringiensis, cry1ac and cry2aa, and the host pf strain, p303, which was with highly antifungal activity to some plant disease fungi and colonizing ability on a wide range of plants. the dna introduction was confirmed by pcr-rflp and southern blot. the 132 kd insecticidal protein was detected in ipp101 and ipp202 by ... | 2000 | 12549049 |
| identification of cry1i-type genes from bacillus thuringiensis strains and characterization of a novel cry1i-type gene. | a pcr-restriction fragment length polymorphism method for identification of cry1i-type genes from bacillus thuringiensis was established by designing a pair of universal primers based on the conserved regions of the genes to amplify 1,548-bp cry1i-type gene fragments. amplification products were digested with the bsp119i and bani enzymes, and four kinds of known cry1i-type genes were successfully identified. the results showed that cry1i-type genes appeared in 95 of 115 b. thuringiensis isolates ... | 2003 | 12957903 |
| insecticidal activity associated with the outer membrane vesicles of xenorhabdus nematophilus. | xenorhabdus nematophilus secretes a large number of proteins into the culture supernatant as soluble proteins and also as large molecular complexes associated with the outer membrane. transmission electron micrographs of x. nematophilus cells showed that there was blebbing of the outer membrane from the surface of the bacterium. the naturally secreted outer membrane vesicles (omvs) were purified from the culture supernatant of x. nematophilus and analyzed. electron microscopy revealed a vesicula ... | 2003 | 12676679 |
| resistance to the cry1ac delta-endotoxin of bacillus thuringiensis in the cotton bollworm, helicoverpa armigera (lepidoptera: noctuidae). | three laboratory strains of helicoverpa armigera (hübner) were established by mating of field-collected insects with an existing insecticide-susceptible laboratory strain. these strains were cultured on artificial diet containing the cry1ac protoxin of bacillus thuringiensis using three different protocols. when no response to selection was detected after 7-11 generations of selection, the three strains were combined by controlled mating to preserve genetic diversity. the composite strain (bx) w ... | 2003 | 14503603 |
| the lymantria dispar nucleopolyhedrovirus contains the capsid-associated p24 protein gene. | during the course of investigations on a wild-type strain of lymantria dispar multinucleocapsid nucleopolyhedrovirus (ldmnpv), a region of the viral genome was analyzed and found to contain 697 bp that is lacking in the sequenced strain (5-6) of ldmnpv (kuzio et al., virology 253, 17-34, 1999). the sequenced strain of ldmnpv contains a mutation in the 25 k few polyhedra (fp) gene, and exhibits the phenotype of a fp mutant. the additional sequence was located at approximately 81.4 map units withi ... | 2003 | 12680688 |
| the characterization of microsporidian isolates (nosematidae: nosema) from five important lepidopteran pests in taiwan. | microsporidian isolates from five lepidopteran pests-spodoptera litura, spodoptera exigua, helicoverpa armigera, plutella xylostella, and pieris spp.-were compared by spore morphology, infectivity to s. litura, western-blot banding patterns, the sequences of small subunit rrna gene (ssurrna sequence), and random amplified polymorphic dna polymerase chain reaction (rapd-pcr). all the isolates could infect experimentally and multiply in the larvae of s. litura. the s. exigua isolate showed the hig ... | 2003 | 12725812 |
| efficacy of transgenic cotton containing a cry1ac gene from bacillus thuringiensis against helicoverpa armigera (lepidoptera: noctuidae) in northern china. | nucotn 33b, a bt transgenic variety of upland cotton (gossypium hirsutum l.) expressing the insecticidal protein cry1ac from bacillus thuringiensis berliner sp. kurstaki, was evaluated for resistance to helicoverpa armigera (hübner) during 1998-2000 in northern china. the results indicated that there was no significant difference in egg densities between nucotn 33b and three nontransgenic varieties (dp5415, zhongmian12, and shiyuan321) during the season, although the survival of larvae on nucotn ... | 2003 | 14503607 |
| first steps to improve cotton crop management in thailand. | thai cotton growers yearly face serious pest problems consisting of heavy infestation associated with resistance to pesticides leading to expensive and harmful pest control practices. thanks to a multi discipline research work carried out from 1991 to 1996, a decision-oriented model for cotton crop management was developed and compared to farmers' practices during the 1988 cotton growing season 1998 in klang hat district, thailand. this model, based on plant monitoring, involved a new cotton cul ... | 2001 | 12425063 |
| drosophila melanogaster sex peptide stimulates juvenile hormone synthesis and depresses sex pheromone production in helicoverpa armigera. | previous studies demonstrate that virgin female adult helicoverpa armigera (lepidoptera: noctuidae) moths exhibit calling behaviour and produce sex pheromone in scotophase from the day after emergence, and that mating turns off both of these pre-mating activities. in the fruit fly drosophila melanogaster, a product of the male accessory glands, termed sex peptide (sp), has been identified as being responsible for suppressing female receptivity after transfer to the female genital tract during ma ... | 1999 | 12770380 |
| evaluation of nostoc strain atcc 53789 as a potential source of natural pesticides. | the cyanobacterium nostoc strain atcc 53789, a known cryptophycin producer, was tested for its potential as a source of natural pesticides. the antibacterial, antifungal, insecticidal, nematocidal, and cytotoxic activities of methanolic extracts of the cyanobacterium were evaluated. among the target organisms, nine fungi (armillaria sp., fusarium oxysporum f. sp. melonis, penicillium expansum, phytophthora cambivora, p. cinnamomi, rhizoctonia solani, rosellinia, sp., sclerotinia sclerotiorum, an ... | 2004 | 15184126 |
| (-)-germacrene d receptor neurones in three species of heliothine moths: structure-activity relationships. | specificity of olfactory receptor neurones plays an important role in food and host preferences of a species, and may have become conserved or changed in the evolution of polyphagy and oligophagy. we have identified a major type of plant odour receptor neurones responding to the sesquiterpene germacrene d in three species of heliothine moths, the polyphagous heliothis virescens and helicoverpa armigera and the oligophagous helicoverpa assulta. the neurones respond with high sensitivity and selec ... | 2003 | 12827423 |
| melanin pigment formation and increased uv resistance in bacillus thuringiensis following high temperature induction. | the pigment melanin is well known to protect against the damaging effects of uv radiation. in this study, we show that thirty-five of thirty-seven tested bacillus thuringiensis strains possess the potential to produce melanin in the presence of l-tyrosin at elevated temperature (42 degrees c). these findings offer a method of protecting insecticidal toxins produced by b. thuringiensis from uv degredation and may therefore have important applications in the field of crop protection. toxicity assa ... | 2004 | 15214633 |
| cloning of biologically active genomes from a helicoverpa armigera single-nucleocapsid nucleopolyhedrovirus isolate by using a bacterial artificial chromosome. | purification of genotypes from baculovirus isolates provides understanding of the diversity of baculoviruses and may lead to the development of better pesticides. here, we report the cloning of different genotypes from an isolate of helicoverpa armigera single-nucleocapsid nucleopolyhedrovirus (hasnpv) by using a bacterial artificial chromosome (bac). a transfer vector (phzb10) was constructed which contained an escherichia coli mini-f replicon cassette within the upstream and downstream arms of ... | 2003 | 14602197 |
| interaction of heliothis armigera nuclear polyhedrosis viral capsid protein with its host actin. | in order to find the cellular interaction factors of the heliothis armigera nuclear polyhedrosis virus capsid protein vp39, a heliothis armigera cell cdna library was constructed. then vp39 was used as bait. the host actin gene was isolated from the cdna library with the yeast two-hybrid system. this demonstrated that vp39 could interact with its host actin in yeast. in order to corroborate this interaction in vivo, the vp39 gene was fused with the green fluorescent protein gene in plasmid pegfp ... | 2002 | 12470589 |
| identification of virulent isolates of the entomopathogenic fungus nomuraea rileyi (f) samson for the management of helicoverpa armigera and spodoptera litura (identification of virulent isolates of n. rileyi). | eleven geographical isolates of the entomopathogenic fungus nomuraea rileyi (farlow) samson of helicoverpa armigera (hubner)/spodoptera litura (fabricius) origin were studied for efficacy against the two host insects. laboratory bioassays at a concentration of 2 x 10(8) conidia ml(-1) indicated that n. rileyi isolates of s. litura origin were better in terms of time taken for mycosis and mortality in both the test larvae: s. litura (77-80% mortality in 7 days) and h. armigera (79-85% in 8 days). ... | 2003 | 14682464 |
| streptomyces sp. 173, an insecticidal micro-organism from marine. | to find new insecticidal antibiotics from marine micro-organisms. | 2004 | 14687212 |
| effect of maysin on wild-type, deltamethrin-resistant, and bt-resistant helicoverpa armigera (lepidoptera: noctuidae). | larvae of the old world corn earworm, helicoverpa armigera (hübner), were fed diets containing lyophilized silks from maize genotypes expressing varying levels of maysin, a flavone glycoside known to be toxic to the new world corn earworm, helicoverpa zea boddie. three different h. armigera colonies were tested: a wild-type colony (96-s), a colony selected for resistance to deltamethrin (del-r), and a colony selected for resistance to the cry1ac protoxin of bacillus thuringiensis (bt-r). a colon ... | 2003 | 12852635 |
| baculovirus studies in new, indigenous lepidopteran cell lines. | eight lepidopteran cell lines were established recently and their susceptibility to different insect viruses was studied. two spodoptera litura cell lines from the larval and pupal ovaries, were found highly susceptible to s. litura nuclear polyhedrosis virus (slnpv, 5-6 x 10(6) npv/ml). the helicoverpa armigera cell line from the embryonic tissue was highly susceptible to h. armigera npv (hanpv, 6.3 x 10(6) npv/ml). these in vitro grown slnpv and hanpv caused 100% mortality to respective 2nd in ... | 2002 | 12561971 |
| new helicoverpa armigera hbn cell line from larval hemocyte for baculovirus studies. | a new cell line from the larval hemocytes of h. armigera was established in grace's medium modified by adding lactalbumin hydrolysate and yeastolate (3.3g/l), and supplemented with fetal bovine serum (20%). the cell line was designated as niv-ha-1195. the cell population at p-78 consisted mainly of epithelial-like cells (89.36%), fibroblast-like cells (8.31%) and giant cells (2.13%). the population doubling time was 96hr at p-8, 60hr at p-43. the chromosome number ranged from 45 to 200. the cell ... | 2002 | 12561972 |
| effect of time of harvest of budded virus on the selection of baculovirus fp mutants in cell culture. | rapid formation and selection of fp (few polyhedra) mutants occurs during serial passaging of helicoverpa armigera nucleopolyhedrovirus (hasnpv) in insect cell culture. the production of hasnpv for use as biopesticides requires the passaging of the virus over a number of passages to produce enough virus inoculum for large-scale fermentation. during serial passaging in cell culture, fp mutants were rapidly selected, resulting in declined productivity and reduced potency of virus. budded virus (bv ... | 2003 | 12573032 |
| mass production of polyhedral occlusion bodies of npv of helicoverpa armigera in relation to dose, age and larval weight. | a significant difference was noticed in the yield of polyhedral occlusion bodies (pobs) in various larval instars of h. armigera when three different doses of the nuclear polyhedrosis virus (npv) were administered. the yield of pobs from a single larva ranged from 0.35 x 10(6) to 25033.33 x 10(6) with a mean of 18422.33 x 10(6) for fourth instar inoculated. positive correlation existed between larval weight and number of pobs recovered. the regression analysis indicated pobs recovered responded ... | 2002 | 12597558 |
| further enhancement of baculovirus insecticidal efficacy with scorpion toxins that interact cooperatively. | we have studied whether the cooperative insecticidal effect of certain scorpion toxin pairs, namely either a combination of excitatory and depressant, or alpha and depressant scorpion toxins, would improve the efficacy of autographa californica nucleopolyhedrovirus (acmnpv) over a virus expressing only a single toxin, towards heliothis virescens, helicoverpa armigera, and spodoptera littoralis larvae. the best result was achieved by combined expression of the excitatory toxin, lqhit1, and the de ... | 2003 | 12606040 |
| [cloning and expression product of vip3a gene from bacillus thuringiensis and analysis of inseceicidal activity]. | the vip3 a gene in a size of 2.3 kb amplified from wild-type bacillus thuringiensis strain s184 by pcr was cloned into pgem-t easy vector and its sequence was analysized by dnastar. the plasmid potp was constructed by inserting vip3a-s184 gene into the expression vector pqe30 and then was transformed into e. coli m15. e. coli m15 cells harbouring the plasmid potp were induced with 1 mmol/l iptg to express 89 kd protein which was confirmed to be vip3a-s184 by western blot. experiments showed that ... | 2002 | 12674638 |
| functional characterization of the ecdysteroid udp-glucosyl transferase gene of helicoverpa armigera single-enveloped nucleopolyhedrovirus isolated in south africa. | the ecdysteroid udp-glucosyltransferase (egt) gene of a single enveloped nucleopolyhedrovirus was located using an hz-snpv gene-specific probe. this snpv was found infecting a colony of helicoverpa armigera (hasnpv) in the western cape region of south africa. the open reading frame of the hasnpv-sa egt is 1.548 nucleotides long and encodes a predicted protein of 516 amino acids with a mr of 58,897-kda. the 5'-noncoding region contained an early transcription initiation motif (cagt) and a baculov ... | 2003 | 12913355 |
| oxidases responsible for resistance to pyrethroids sensitize helicoverpa armigera (hübner) to triazophos in west africa. | helicoverpa armigera (hübner) is the major insect pest of cotton in africa, turkey, asia, india, indonesia and australia. populations recently developed resistance to pyrethroids in west africa via the overproduction of cytochrome p450 (oxidases) increasing pyrethroid metabolism. one way to overcome pyrethroid resistance is to use compounds that show negative cross-resistance to pyrethroids. triazophos is one of these compounds: it is slightly more toxic against pyrethroid resistant larvae of h. ... | 2003 | 12915179 |
| mechanisms and diversity of resistance to insect pests in wild relatives of groundnut. | the levels of resistance to insect pests in cultivated groundnut (arachis hypogaea) germplasm are quite low, and therefore, we screened 30 accessions of arachis spp. and 12 derived lines for resistance to insect pests under field and greenhouse conditions. accessions belonging to arachis cardenasii, arachis duranensis, arachis kempff-mercadoi, arachis monticola, arachis stenosperma, arachis paraguariensis, arachis pusilla, and arachis triseminata showed multiple resistance to the leaf miner apro ... | 2003 | 14977130 |
| interaction of bacillus thuringiensis toxins with larval midgut binding sites of helicoverpa armigera (lepidoptera: noctuidae). | in 1996, bt-cotton (cotton expressing a bacillus thuringiensis toxin gene) expressing the cry1ac protein was commercially introduced to control cotton pests. a threat to this first generation of transgenic cotton is the evolution of resistance by the insects. second-generation bt-cotton has been developed with either new b. thuringiensis genes or with a combination of cry genes. however, one requirement for the "stacked" gene strategy to work is that the stacked toxins bind to different binding ... | 2004 | 15006756 |
| the extracellular constitutive production of chitin deacetylase in metarhizium anisopliae: possible edge to entomopathogenic fungi in the biological control of insect pests. | the possible contribution of extracellular constitutively produced chitin deacetylase by metarhizium anisopliae in the process of insect pathogenesis has been evaluated. chitin deacetylase converts chitin, a beta-1,4-linked n-acetylglucosamine polymer, into its deacetylated form chitosan, a glucosamine polymer. when grown in a yeast extract-peptone medium, m. anisopliae constitutively produced the enzymes protease, lipase, and two chitin-metabolizing enzymes, viz. chitin deacetylase (cda) and ch ... | 2004 | 15050837 |
| lyophilization of lepidopteran midguts: a preserving method for bacillus thuringiensis toxin binding studies. | binding assays with brush border membrane vesicles (bbmv) from insect midguts are commonly used in the study of the interactions between bacillus thuringiensis cry toxins and their receptors. collaboration between laboratories often require that frozen insect samples are sent in dry ice. because of customs restrictions and delays, sample thawing is always a risk and often the biological material becomes ruined during shipping. we have tested lyophilization as an alternative method for preserving ... | 2004 | 15109901 |
| characterization of a digestive carboxypeptidase from the insect pest corn earworm (helicoverpa armigera) with novel specificity towards c-terminal glutamate residues. | carboxypeptidases were purified from guts of larvae of corn earworm (helicoverpa armigera), a lepidopteran crop pest, by affinity chromatography on immobilized potato carboxypeptidase inhibitor, and characterized by n-terminal sequencing. a larval gut cdna library was screened using probes based on these protein sequences. cdna haca42 encoded a carboxypeptidase with sequence similarity to enzymes of clan mc [barrett, a. j., rawlings, n. d. & woessner, j. f. (1998) handbook of proteolytic enzymes ... | 2004 | 15128309 |
| comparison of anti-feedant and insecticidal activity of nimbin and salannin photo-oxidation products with neem (azadirachta indica) limonoids. | photo-oxidation of the neem limonoids nimbin and salannin with uv light in the presence of oxygen gives two isomeric lactone products per limonoid, nimbinolide and isonimbinolide, and salanninolide and isosalanninolide, respectively. when compared in insect tests with the important limonoids of neem seeds, azadirachtin, nimbin and salannin, isonimbinolide and isosalanninolide show activity greater than that of nimbin or salannin and in some respects show activity approaching that of azadirachtin ... | 2004 | 15154512 |
| characterization of two autographa californica nucleopolyhedrovirus proteins, ac145 and ac150, which affect oral infectivity in a host-dependent manner. | the genome of the baculovirus autographa californica nuclear polyhedrosis virus (acmnpv) contains two homologues, orf145 and orf150, of the heliothis armigera entomopoxvirus (haepv) 11,000-kda gene. polyclonal antibodies raised against the ac145 or ac150 protein were utilized to demonstrate that they are expressed from late to very late times of infection and are within the nuclei of infected sf-21 cells. transmission electron microscopy coupled with immunogold labeling of ac145 found this prote ... | 2004 | 15163737 |
| type-a allatostatins from the fall armyworm, spodoptera frugiperda: molecular cloning, expression and tissue-specific localization. | the gene encoding the spodoptera frugiperda allatostatin type-a peptide family (y/fxfgl-amides) was isolated from s. frugiperda brain cdna. the gene encodes a precursor of 231 amino acids containing nine (or ten) y/fxfgl-a peptides that are tandemly arranged in three blocks. the comparison of the spofr-ast a precursor with the respective precursor genes from two other lepidopteran species, helicoverpa armigera and bombyx mori, shows high homology in size, sequence (84 and 57%, respectively), and ... | 2004 | 15211550 |
| changes in susceptibility to conventional insecticides of a cry1ac-selected population of helicoverpa armigera (hübner) (lepidoptera: noctuidae). | the changes in the susceptibility of the cotton bollworm, helicoverpa armigera (hübner) to three insecticides (lambda-cyhalothrin, phoxim and endosulfan) commonly used for control of this pest in china were monitored by bioassays at various generations. the insects were originally collected from bt cotton fields and selected with cry1ac over 44 generations. in comparison with a susceptible strain, the larval resistance of the bt-selected populations to cry1ac toxin increased 106-fold. simultaneo ... | 2004 | 15260299 |
| molecular cloning and expression patterns of the molt-regulating transcription factor hhr3 from helicoverpa armigera. | molt-regulating transcription factors, hormone receptor 3 (hr3), play important roles in regulating expression of tissue-specific genes involved in insect molting and metamorphosis. a 1668 bp cdna encoding a molt-regulating transcription factor (hhr3) was cloned from helicoverpa armigera, which encodes a protein made up of 556 amino acids. this 62 kda protein was found to have an isoelectric point (pi) of 6.52. there was no signal peptide or n-glycosylation site found in this cdna. a dna-binding ... | 2004 | 15271213 |
| bioactivity of non-edible oil seed extracts and purified extracts against helicoverpa armigera (hubner). | extracts and purified extracts of seeds of two plant species, madhuca latifolia and calophyllum inophyllum when evaluated against the 2nd instar larvae of helicoverpa armigera reared on synthetic diet, exhibited high larval mortality, prolongation of developmental period, morphological deformities and highly significant reduction in adult emergence. the reduction in larval weights in the treatments was also highly significant. | 2004 | 15274488 |
| in vivo enhancement of nucleopolyhedrovirus of oriental armyworm, mythimna separata using spindles from helicoverpa armigera entomopoxvirus. | when the third instar larvae of m. separata were exposed to eight varying concentrations of polyhedral occlusion bodies (pob's) of nucleopolyhedrovirus of m. separata (msnpv) ranging from 2.6 x 10(-1) to 2.6 x 10(8) pob's/ml, the percent mortality and incubation period ranged from 16-100% and 14 to 9 days respectively. on the other hand when the same third instar larvae of m. separata were exposed to only five varying concentration of pob's of msnpv ranging from 2.6 x 10(2) to 2.6 x 10(6), pob's ... | 2004 | 15274494 |
| potentiation of insecticidal activity of bacillus thuringiensis subsp. kurstaki hd-1 by proteinase inhibitors in the american bollworm, helicoverpa armigera (hübner). | the effect of crude proteinase inhibitor extracts from seeds of different crop plants (black gram, chickpea, chickling vetch, finger millet, french bean, green gram, horse gram, lentil, pea and soybean) on the insecticidal activity of b. thuringiensis var. kurstaki hd-1 was investigated against neonate larvae of h. armigera by diet incorporation method. the larval mortality due to crude proteinase inhibitors alone (5% seed weight equivalent) ranged from 4.1 to 19.1%; the maximum mortality with f ... | 2004 | 15282948 |
| seasonal expression profiles of insecticidal protein and control efficacy against helicoverpa armigera for bt cotton in the yangtze river valley of china. | seasonal levels of bacillus thuringiensis (bt) insecticidal protein and its control efficacy against helicoverpa armigera (hübner) in bt transgenic cotton gk19 (carrying a cry1ac/cry1ab fused gene) and bg1560 (carrying a cry1ac gene) were investigated in tianmen county, hubei province, located in the yangtze river valley of china, in 2001 and 2002. the results showed that the toxin content in bt cotton changed significantly over time, and that the structure, growth stage, and variety were signif ... | 2005 | 15765683 |
| a novel secreted protein toxin from the insect pathogenic bacterium xenorhabdus nematophila. | the bacterium xenorhabdus nematophila is an insect pathogen that produces several proteins that enable it to kill insects. screening of a cosmid library constructed from x. nematophila strain a24 identified a gene that encoded a novel protein that was toxic to insects. the 42-kda protein encoded by the toxin gene was expressed and purified from a recombinant system, and was shown to kill the larvae of insects such as galleria mellonella and helicoverpa armigera when injected at doses of around 3 ... | 2004 | 14707137 |
| a kunitz trypsin inhibitor from chickpea (cicer arietinum l.) that exerts anti-metabolic effect on podborer (helicoverpa armigera) larvae. | chickpea (cicer arietinum l.) seeds contain bowman-birk proteinase inhibitors, which are ineffective against the digestive proteinases of larvae of the insect pest helicoverpa armigera. we have identified and purified a low expressing proteinase inhibitor (pi), distinct from the bowman-birk inhibitors and active against h. armigera gut proteinases (hgp), from chickpea seeds. n-terminal sequencing of this hgp inhibitor revealed a sequence similar to reported pea (pisum sativum) and chickpea alpha ... | 2005 | 15830127 |
| characterization of a cytotoxic pilin subunit of xenorhabdus nematophila. | xenorhabdus nematophila is an insect pathogenic bacterium, known to produce protein toxins that kill the larval host. we have described a cytotoxic pilin subunit of x. nematophila, which is expressed on the cell surface and also secreted in the extracellular medium associated with outer membrane vesicles. a 17kda pilin subunit was isolated and purified from x. nematophila cell surface. the protein showed cytotoxicity to larval hemocytes of helicoverpa armigera in an in vitro assay, causing agglu ... | 2004 | 14751223 |
| development and mechanisms of resistance to bacillus thuringiensis endotoxin cry1ac in the american bollworm, helicoverpa armigera (hübner). | the american bollworm, h. armigera, evolved 31-fold resistance to selection pressure of b. thuringiensis endotoxin cry1ac within six generations. the cry1ac selected larvae of h. armigera showed cross-resistance to cry1aa and cry1ab both in terms of mortality and growth reduction. studies on mechanisms of resistance to cry1ac showed that proteases of resistant insects degraded cry1ac faster than those of susceptible insects, which led to the relative unavailability of toxin of about 58 kda for b ... | 2004 | 15282949 |
| long-term selection for resistance to transgenic cotton expressing bacillus thuringiensis toxin in helicoverpa armigera (hübner) (lepidoptera: noctuidae). | selection experiments for resistance to transgenic bt cotton expressing cry1ac toxin in helicoverpa armigera (hübner) were conducted using a leaf-feeding method with 42 selection episodes over 45 generations. the cotton bollworm developed resistance to transgenic bt cotton after 12 generations (f12) of selection. the survival rate of f12 neonates feeding on leaves of seedling stage for 4 days and boll-opening stage for 5 days of r19 line were ca 34 and 72%, respectively, compared with ca 0 and 4 ... | 2004 | 14971684 |
| the synergistic activity between cry1aa and cry1c from bacillus thuringiensis against spodoptera exigua and helicoverpa armigera. | to investigate the interaction between two crystal proteins, cry1aa and cry1c, for future development of biopesticides based on bacillus thuringiensis, toxicities of the two individual proteins and in combinations have been determined against spodoptera exigua and helicoverpa armigera larvae, and synergism between the proteins has been evaluated using synergistic factor. | 2005 | 15892743 |
| [response of parasitic wasps of cotton bollworm to different cotton varieties with transgenic bacillus thringienthsis genes]. | the relationship between the parasitic wasp population number of cotton bollworm (helicoverpa armigera) and the varieties of cotton was studied by releasing and collecting the eggs and larvae of cotton bollworm on transgenic and non-transgenic cottons. the research results from 2000 to 2003 showed that the parasitic rates of the eggs and larvae of cotton bollworm were notably lower in transgenic cotton field than in non-transgenic cotton field. at the same time, the effect of transgenic and non- ... | 2004 | 15320406 |
| occurrence and cross infectivity of granulovirus of field bean pod borer adisura atkinsoni moore. | a granulovirus (gv) was isolated from the field-bean pod borer, adisura atkinsoni. electron microscopic observation showed capsule or granular shaped occlusion bodies. the virus was highly virulent against second instar larvae when tested at 1 x 10(6) occlusions/larva through food surface (pod/seed) contamination technique. the incubation period ranged from 6-10 days in the case of second instar larvae. in contrast to green coloured healthy larvae. gv infected a. atkinsoni became brownish/pale w ... | 2003 | 15332511 |
| molecular cloning and bacterial expression of pheromone binding protein in the antennae of helicoverpa armigera (hübner). | a cdna clone coding for pheromone binding protein was isolated from the antennae of helicoverpa armigera by rt-pcr and (5'/3')-race technique. the full-length of h. armigera pheromone binding protein (harmpbp) was 952 bp, possessing 162 amino acid residues including a signal peptide of 20 amino acids. its predicted molecular weight and isoelectric point were 18.26 kda and 5.23, respectively. this deduced amino acid sequence shared some common structural features with odorant-binding proteins fro ... | 2004 | 15352152 |
| the evolution of cotton pest management practices in china. | the development of cotton pest management practices in china has followed a pattern seen for many crops that rely heavily on insecticides. helicoverpa armigera resistance to chemical pesticides resulted in the unprecedented pest densities of the early 1990s. transgenic cotton that expresses a gene derived from the bacterium bacillus thuringiensis (bt) has been deployed for combating h. armigera since 1997. the pest management tactics associated with bt cotton have resulted in a drastic reduction ... | 2005 | 15355239 |
| insecticidal pilin subunit from the insect pathogen xenorhabdus nematophila. | xenorhabdus nematophila is an insect pathogen and produces protein toxins which kill the larval host. previously, we characterized an orally toxic, large, outer membrane-associated protein complex from the culture medium of x. nematophila. here, we describe the cloning, expression, and characterization of a 17-kda pilin subunit of x. nematophila isolated from that protein complex. the gene was amplified by pcr, cloned, and expressed in escherichia coli. the recombinant protein was refolded in vi ... | 2004 | 15375127 |
| expression of the helicoverpa cathepsin b-like proteinase during embryonic development. | cathepsin b-like proteinase from helicoverpa armigera (hcb) was proposed as being involved in the degradation of yolk proteins during embryonic development. recombinant hcb was expressed as a fusion protein with gst in escherichia coli bl21 on the basis of its cdna and purified to homogeneity. the fusion protein was cleaved with thrombin to generate a soluble protease with a mass of 37 kda. a polyclonal antiserum against this recombinant protein, raised in the rabbit, recognized three isoforms o ... | 2005 | 15599933 |
| helicostatins: brain-gut peptides of the moth, helicoverpa armigera (lepidoptera: noctuidae). | gene expression and immunolocalisation studies have determined that the helicostatins are brain-gut peptides in larvae of the lepidopteran, helicoverpa armigera. mapping of the distribution of these peptides in the nervous system and alimentary canal has provided evidence for multifunctional regulatory roles. in situ hybridisation studies have shown that the helicostatin precursor gene is expressed in neurones of the central and stomatogastric nervous systems, and endocrine cells of the midgut d ... | 2005 | 15599938 |
| bioefficacy and mode-of-action of some limonoids of salannin group from azadirachta indica a. juss and their role in a multicomponent system against lepidopteran larvae. | biological activities of the salannin type of limonoids isolated from azadirachta indica a. juss were assessed using the gram pod borer helicoverpa armigera (hubner) and the tobacco armyworm spodoptera litura (fabricius) (lepidoptera: noctuidae). inhibition of larval growth was concomitant with reduced feeding by neonate and third instar larvae. all three compounds exhibited strong antifeedant activity in a choice leaf disc bioassay with 2.0, 2.3 and 2.8 microg/cm(2) of 3-o-acetyl salannol, sala ... | 2004 | 15625397 |
| regional reversion of insecticide resistance in helicoverpa armigera (lepidoptera: noctuidae) is associated with the use of bt cotton in northern china. | a continuous programme for monitoring resistance of helicoverpa armigera (hubner) to commonly used insecticides was undertaken for assessing the impact of bt cotton planting on the evolution of the pest resistance from 1994 to 2002 in china. the bioassay results showed that the resistance levels per year in field populations of h armigera to lambda-cyhalothrin, phoxim and endosulfan decreased, respectively, to 9-15-fold, 11-14-fold and 6-8-fold in 2001-2002 from 197-262-fold, 52-74-fold and 18-3 ... | 2005 | 15643649 |
| northward migration of helicoverpa armigera (lepidoptera: noctuidae) and other moths in early summer observed with radar in northern china. | the northward migration of helicoverpa armigera (hübner) and other moths in early summer was observed with radar in 2001 and 2002 at langfang, hebei province, china. migratory flights typically occurred at heights up to 1.2 km above ground level (agl), and high density layer concentrations frequently formed at 200-300 m agl. adult moths of local populations took off at dusk and ceased flight approximately 0.5 h before sunrise with area density peaking approximately 35 min after dusk. a strong du ... | 2004 | 15666739 |
| disruption of a cadherin gene associated with resistance to cry1ac {delta}-endotoxin of bacillus thuringiensis in helicoverpa armigera. | a laboratory strain (gy) of helicoverpa armigera (hubner) was established from surviving larvae collected from transgenic cotton expressing a bacillus thuringiensis var. kurstaki insecticidal protein (bt cotton) in gaoyang county, hebei province, people's republic of china, in 2001. the gybt strain was derived from the gy strain through 28 generations of selection with activated cry1ac delivered by diet surface contamination. when resistance to cry1ac in the gybt strain increased to 564-fold aft ... | 2005 | 15691952 |
| neuropeptide co-localisation in the lepidopteran frontal ganglion studied by electron-microscopic gold-labelling immunocytochemistry. | an immunogold-labelling electron-microscopic study of the frontal ganglion of two noctuids, lacanobia oleracea and helicoverpa armigera, has been carried out with antisera directed against three neuropeptides; allatostatins of the y/fxfgl-nh2 type, manduca sexta allatostatin (mas-as) and m. sexta allatotropin. the ganglion of both noctuids has two pairs of large peptidergic neurones with many clusters of electron-dense granules, one pair being situated anteriorly and the other posteriorly. by me ... | 2005 | 15714283 |
| construction of a transposon-mediated baculovirus vector hanpvid and a new cell line for expressing barnase. | in this study we developed the transposon-mediated shuttle vector 'hanpvid', which composed of hanpv (heliothis armigera nuclear polyhedrosis virus) genomic dna and a transposon cassette from bacmid of bac-to-bac system. hanpvid replicates in e. coli in the same way as bacmid and retains infective function in cotton bollworm cells (hz-am1). using hanpvid we constructed a recombinant virus, which could infect hz-am1 cells and generate recombinant hanpv (rha-bar) containing the barnase gene, a rib ... | 2005 | 15715945 |
| in vivo and in vitro effect of capsicum annum proteinase inhibitors on helicoverpa armigera gut proteinases. | two proteinase inhibitors (pis), capa1 and capa2, were purified from capsicum annum linn. var. phule jyoti leaves and assessed for their in vitro and in vivo activity against helicoverpa armigera gut proteinases (hgps). both the inhibitors exhibited molecular weights of about 12 kda with inhibitory activity against bovine trypsin and chymotrypsin indicating presence of probable two-inhibitor repeats of pin ii family. capa1 and capa2 inhibited 60-80% hgp (azocaseinolytic) activity of fourth insta ... | 2005 | 15715970 |
| isolation and identification of a new tetravirus from dendrolimus punctatus larvae collected from yunnan province, china. | in this study, dendrolimus punctatus tetravirus (dptv) has been identified as a new member of the genus omegatetravirus of the family tetraviridae that may be related serologically to nudaurelia capensis omega virus (nomegav). dptv particles are isometric, with a diameter of about 40 nm and a buoyant density of 1.281 g cm(-3) in cscl. the virus has two capsid proteins (of 62 500 and 6800 da) and two single-stranded rna molecules (rna1 and rna2), which are 5492 and 2490 nt long, respectively. rna ... | 2005 | 15722541 |
| maturation of a tetravirus capsid alters the dynamic properties and creates a metastable complex. | the assembly of monomeric protein subunits into a viral capsid is a finely tuned molecular process. in response to subtle changes in environmental conditions, this supramolecular complex can dramatically reorganize. defining the forces that control this structure and the cooperative action of subunits has implications for biology and nanotechnology. the small icosahedral rna tetravirus family members nudaurelia omega capensis (nomegav) and helicoverpa armigera stunt virus (hasv) can be purified ... | 2005 | 15749119 |
| characterization of melanin produced by a wild-type strain of bacillus thuringiensis. | bt l-7601 is a uv resistant wild-type strain, which belongs to bacillus thuringiensis subsp. dendrolimus serotype h4a4b. it was isolated from nature, and produced a dark brown pigment during the exponential phase of growth. bt l-7601 had the ability to produce pigment in a general nutrition-abundant medium, which had no l-tyrosine. the pigment was identified as melanin based on chemical testing, its light absorbance, and ft-ir analysis. bt l-7601 has a strong resistance to uv light. after 30 min ... | 2004 | 15754243 |
| preliminary studies on differential defense responses induced during plant communication. | we compared the expression patterns of three representative genes in undamaged tomato and tobacco plants in response to exposure to either tomato or tobacco fed on by helicoverpa armigera (cotton bollworm). when tomato and tobacco, two species of one family, were incubated in the chambers with the tomato plants damaged by the cotton bollworm, the expression of the pr1, bgl2, and pal genes was up-regulated in leaves of both plants. however, the levels of gene expression were significantly higher ... | 2005 | 15780181 |
| characterization of helicoverpa armigera nucleopolyhedrovirus orf33 that encodes a novel budded virion derived protein, bv-e31. | homologues of helicoverpa armigera nucleopolyhedrovirus (hearsnpv) orf33 are found in all 22 completely sequenced members of the lepidopteran nucleopolyhedroviruses and granuloviruses, but so far their functions are unknown. in this report, we describe the characterization of hearsnpv orf33 (ha33). northern blot analysis showed a single transcript of ha33 of approximately 0.7 kb was transcribed beginning at 3 h post-infection in infected helicoverpa zea cells (hzam1) and the gene product could b ... | 2005 | 15834653 |
| molecular characterization and expression of prothoracicotropic hormone during development and pupal diapause in the cotton bollworm, helicoverpa armigera. | using a strategy of rapid amplification of cdna ends, the cdna encoding prothoracicotropic hormone (ptth) was cloned from the brain of helicoverpa armigera (hearm). the hearm-ptth cdna contains an open reading frame encoding a 226-amino acid preprohormone, which shows high identity with the closely related noctuid moths, helicoverpa zea (98%) and heliothis virescens (94%), and low identity with five species of bombycoidea: bombyx mori (57%), manduca sexta (55%), hyalophora cecropia (52%), samia ... | 2005 | 15869761 |
| new resistance mechanism in helicoverpa armigera threatens transgenic crops expressing bacillus thuringiensis cry1ac toxin. | in australia, the cotton bollworm, helicoverpa armigera, has a long history of resistance to conventional insecticides. transgenic cotton (expressing the bacillus thuringiensis toxin cry1ac) has been grown for h. armigera control since 1996. it is demonstrated here that a population of australian h. armigera has developed resistance to cry1ac toxin (275-fold). some 70% of resistant h. armigera larvae were able to survive on cry1ac transgenic cotton (ingard) the resistance phenotype is inherited ... | 2005 | 15870346 |
| is the mature endotoxin cry1ac from bacillus thuringiensis inactivated by a coagulation reaction in the gut lumen of resistant helicoverpa armigera larvae? | bacillus thuringiensis endotoxins (bt-toxins) are the most important biopesticides used in controlling insect pests and vectors of diseases. the emergence of widespread resistance to bt in some insect species is a serious threat to agricultural production. analysis of bt-resistant and susceptible laboratory strains of helicoverpa armigera revealed elevated immune responses involving increased melanization and the presence of a soluble toxin-binding glycoprotein in the hemolymph and gut lumen of ... | 2005 | 15894190 |
| cdna cloning and heterologous expression of a wheat proteinase inhibitor of subtilisin and chymotrypsin (wsci) that interferes with digestive enzymes of insect pests. | a cdna encoding the proteinase inhibitor wsci (wheat subtilisin/chymotrypsin inhibitor) was isolated by rt-pcr. degenerate oligonucleotide primers were designed based on the amino acid sequence of wsci and on the nucleotide sequence of the two homologous inhibitors (ci-2a and ci-2b) isolated from barley. for large-scale production, wsci cdna was cloned into the e. coli vector pgex-2t. the fusion protein gst-wsci was efficiently produced in the bacterial expression system and, as the native inhib ... | 2005 | 15899701 |
| streptomyces avermitilis from marine. | the insecticidal strain 173 was isolated from marine source and its activity was explored by the bioassay of brine shrimp and helicoverpa armigera. based on morphological, physiological and molecular properties, the insecticidal strain 173 was identified as streptomycetes avermitilis, which is the best insecticidal microorganism found in the terrestrial environment. the taxonomy of the strain 173, insecticidal spectrum and properties of the corresponding insecticidal antibiotics are reported. | 2005 | 15900773 |
| cricket paralysis virus, a potential control agent for the olive fruit fly, dacus oleae gmel. | representatives of several families of insect viruses were tested for growth and pathogenicity in the olive fruit fly, dacus oleae gmel. the viruses included nuclear polyhedrosis viruses, an iridovirus, two picornaviruses, and trichoplusia ni small rna virus (a member of the nudaurelia beta family), in addition to two naturally occurring viruses of the olive fruit fly. two viruses, one of the two picornaviruses (cricket paralysis virus [crpv] and the iridovirus (type 21 from heliothis armigera), ... | 1987 | 16347255 |
| selection and heritability of resistance to bacillus thuringiensis subsp kurstaki and transgenic cotton in helicoverpa armigera (lepidoptera: noctuidae). | compared with an unselected susceptible population, a cotton bollworm, helicoverpa armigera (hübner), population selected for 22 generations with transgenic cotton leaves (modified cry1a) in the laboratory developed 11.0-fold resistance to cry1ac (one single-protein product mvpii). resistance to bacillus thuringiensis berliner subsp kurstaki (btk) was selected for 22 generations with a 5.2-fold increase in lc50. the estimated realized heritabilities (h2) of resistance for transgenic-cotton- and ... | 2004 | 15382503 |
| ha-vp39 binding to actin and the influence of f-actin on assembly of progeny virions. | we present evidence that actin is necessary for the successful assembly of hanpv virions. purified nucleocapsid protein ha-vp39 of heliothis armigera nuclear polyhedrosis virus (hanpv) was found to be able to bind to actin in vitro without assistance, as demonstrated by western blot and isothermal titration calorimeter. deltah and binding constants (k) detected by isothermal titration calorimeter strongly suggested that ha-vp39 first binds actin to seed the formation of hexamer complex of actin, ... | 2004 | 15503206 |
| relative fitness of cry1a-resistant and -susceptible helicoverpa armigera (lepidoptera: noctuidae) on conventional and transgenic cotton. | glasshouse and laboratory experiments were conducted to evaluate the relative fitness of cry1a-susceptible and laboratory-selected resistant strains of helicoverpa armigera (hübner). life history parameters of h. armigera larvae feeding on young cotton plants showed a significant developmental delay of up to 7 d for the resistant strain compared with the susceptible strain on non-bacillus thuringiensis (bt) cotton. this fitness cost was not evident on artificial diet. there was no developmental ... | 2004 | 15568362 |
| vegetative insecticidal protein enhancing the toxicity of bacillus thuringiensis subsp kurstaki against spodoptera exigua. | the objective of this work was to enhance the insecticidal activity or widen the pesticidal spectrum of a commercial bacillus thuringiensis strain ybt1520. | 2006 | 16441373 |
| [bacillus thuringiensis helper protein p20 affects the formation of cry1ab]. | the cry1ab differs most significantly from the other related icps by its absence of a carboxyl terminus of 28 amino acids including four cysteines; consequently it is less stable. we report that the helper protein p20 plays a role in the expression and crystallization of cry1ab. three cry1ab expression plasmids pt1b, pp1b, and pdp1b, were constructed based on the shuttle vector pht3101. the vector pt1b does not contain the p20 gene, pp1b carries p20, and pdp1b contains p20 with cry1a(c) promoter ... | 2003 | 15969085 |
| txp40, a ubiquitous insecticidal toxin protein from xenorhabdus and photorhabdus bacteria. | xenorhabdus and photorhabdus are gram-negative bacteria that produce a range of proteins that are toxic to insects. we recently identified a novel 42-kda protein from xenorhabdus nematophila that was lethal to the larvae of insects such as galleria mellonella and helicoverpa armigera when it was injected at doses of 30 to 40 ng/g larvae. in the present work, the toxin gene txp40 was identified in another 59 strains of xenorhabdus and photorhabdus, indicating that it is both highly conserved and ... | 2006 | 16461722 |
| association analysis between serotype, cry gene content, and toxicity to helicoverpa armigera larvae among bacillus thuringiensis isolates native to spain. | serotyping, cry gene content, and toxicity to helicoverpa armigera were determined for 178 isolates of bacillus thuringiensis native to spain. a total of 13 different cry1 and cry2 genes were detected when isolates were screened by pcr analysis. results showed that cry2 and cry1ia were the most frequent cry genes in the collection (74 and 57%, respectively); whereas cry1d, cry1aa, cry1ab, and cry1c were only moderately abundant (49, 48, 47, and 36%, respectively). the most uncommon cry genes wer ... | 2005 | 16019024 |
| season-long variation in expression of cry1ac gene and efficacy of bacillus thuringiensis toxin in transgenic cotton against helicoverpa armigera (lepidoptera: noctuidae). | the insertion of genes encoding insecticidal cry1a delta-endotoxins from the bacterium bacillus thuringiensis berliner variety kurstaki (bt) into varieties of cotton (gossypium spp.) was undertaken to assist in the control of a range of lepidopteran pests. in australia, where helicoverpa armigera (hübner) and helicoverpa punctigera (wallengren) are major pests, the level of control is useful, but not complete, because efficacy declines as the crop matures. fluctuations in the efficacy of bt cott ... | 2005 | 16022333 |
| comparative venom toxicity between pteromalus puparum and nasonia vitripennis (hymenoptera: pteromalidae) toward the hemocytes of their natural hosts, non-target insects and cultured insect cells. | crude venoms from two parasitoid species, pteromalus puparum and nasonia vitripennis (hymenoptera: pteromalidae) were assayed for biological activities toward hemocytes from two species of their natural hosts and eight species of their non-natural hosts as well as two lines of cultured lepidoptera cells, respectively. by inhibiting the spreading and viability of insect hemocytes, the venom from p. puparum displayed significantly higher activities toward plasmatocytes and granular cells from both ... | 2005 | 16026808 |
| return migration of helicoverpa armigera (lepidoptera: noctuidae) during autumn in northern china. | the autumn migration of helicoverpa armigera (hübner) was observed with radar and two types of light-trap at langfang, hebei province, china in 2001 and 2002. the sudden increase in the proportion of h. armigera moths in the searchlight trap indicated migration into the area and catches increased 10-fold during the second half of the night due to the landing of migrants before dawn. the moths' migratory flights took place at up to 2000 m above the ground, and moths flew differentially at times, ... | 2005 | 16048684 |
| gene-flow between populations of cotton bollworm helicoverpa armigera (lepidoptera: noctuidae) is highly variable between years. | both large and small scale migrations of helicoverpa armigera hübner in australia were investigated using amova analysis and genetic assignment tests. five microsatellite loci were screened across 3142 individuals from 16 localities in eight major cotton and grain growing regions within australia, over a 38-month period (november 1999 to january 2003). from november 1999 to march 2001 relatively low levels of migration were characterized between growing regions. substantially higher than average ... | 2005 | 16048686 |
| functional analysis of fp25k of helicoverpa armigera single nucleocapsid nucleopolyhedrovirus. | the fp25k gene of helicoverpa armigera single nucleocapsid nucleopolyhedrovirus (hearnpv) was studied. hearnpv fp25k gene transcription was found starting from about 18 h post-infection, and protein could be detected from the same time with antiserum against fp25k. to study the function of hearnpv fp25k, a recombinant hearnpv (habacwd11) with an enhanced green fluorescent protein (gfp) gene replacing the fp25k was constructed using habachz8, a bacmid of hearnpv that lacks the polyhedrin gene. gr ... | 2005 | 16099901 |
| common receptor for bacillus thuringiensis toxins cry1ac, cry1fa, and cry1ja in helicoverpa armigera, helicoverpa zea, and spodoptera exigua. | binding studies using (125)i-cry1ac and biotinylated cry1fa toxins indicate the occurrence of a common receptor for cry1ac, cry1fa, and cry1ja in helicoverpa armigera, helicoverpa zea, and spodoptera exigua. our results, along with previous binding data and the observed cases of cross-resistance, suggest that this pattern seems to be widespread among lepidopteran species. | 2005 | 16151165 |
| fitness of cry1a-resistant and -susceptible helicoverpa armigera (lepidoptera: noctuidae) on transgenic cotton with reduced levels of cry1ac. | the performance of helicoverpa armigera (hübner) on 15-wk-old cotton plants was compared for a susceptible strain, a near-isogenic laboratory-selected strain, and f1 progeny of the two strains. glasshouse experiments were conducted to test the three insect types on conventional plants and transgenic plants that produced the bacillus thuringiensis (bt) toxin cry1ac. at the time of testing (15 wk), the cry1ac concentration in cotton leaves was 75% lower than at 4 wk. on these plants, < 10% of susc ... | 2005 | 16156585 |
| changes in cry1ac bt transgenic cotton in response to two environmental factors: temperature and insect damage. | the efficacy of cry1ac bacillus thuringiensis (bt) cotton plants against field populations of helicoverpa armigera (hübner) has been inconsistent over the growing season. any reduction in efficacy (where efficacy is the capacity of the plant to affect the survival of the insect) increases the opportunities for h. armigera to evolve resistance to bt toxin. changes in efficacy could be due to changes at the level of gene expression and/or in the physiological makeup of the plant and may be induced ... | 2005 | 16156594 |
| structural organization and expression analysis of the cdna encoding allatotropin in the cotton bollworm, helicoverpa armigera. | the cdna encoding allatotropin (at), which stimulates juvenile hormone (jh) biosynthesis by the adult corpora allata (ca) of lepidoptera, was cloned from helicoverpa armigera (har). har-at cdna encodes a 135-amino acid polypeptide precursor containing a 13-amino acid at sequence identical to manduca sexta at (mas-at). three other h. armigera at cdnas encoding 172, 213, and 246 amino acids were also cloned. the four isoforms were produced by alternative splicing and termed har-at1, -at2, -at3, an ... | 2005 | 16175534 |
| comparative biological activities of a plaque-purified variant and a turkish native isolate of splinpv-b against spodoptera littoralis (lepidoptera: noctuidae). | the noctuid moth spodoptera littoralis (boisduval) is an important pest of many cultivated plants worldwide and five different geographical nucleopolyhedrovirus (npv) strains of this pest have been isolated to date. two of these, a plaque-purified variant of the s. littoralis npv from morocco (splinpv-m2) and a splinpv isolated from field-infected s. littoralis larvae found in turkey (splinpv-tr1), were compared biologically in terms of infectiveness (median lethal dose, ld50) for third instars ... | 2006 | 16235266 |
| gene cloning and expression of cadherin in midgut of helicoverpa armigera and its cry1a binding region. | cadherins belong to one of the families of animal glycoproteins responsible for calcium-dependent cell-cell adhesion. recent literatures showed that the cadherin-like in midgut of several insects served as the receptor of bt toxin cry1a and the variation of cadherin-like is related to insect's resistance to cry1a. the full-length cdna encoding cadherin-like of helicoverpa armigera is cloned by degenerate pcr and race techniques and the gene was designated as btr-harm, which is 5581 bp in full-le ... | 2005 | 16248428 |
| characterization of orf2 and its encoded protein of the helicoverpa armigera nucleopolyhedrovirus. | the open reading frame 2 (ha2) of the helicoverpa armigera single nucleocapsid nucleopolyhedrovirus (hasnpv), a conserved gene in most baculoviruses from lepidopteran insects such as p78/83 of the autographa californica mnpv, was characterized. it is 1,242 bp long and potentially encodes a 45.9 kda. ha2 is conserved among baculoviruses from lepidopteran insects. ha2 transcripts were detected from 16 to 96 h post infection (hpi) of hzam1 cells. rabbit polyclonal antiserum against a gst-ha2 fusion ... | 2006 | 16249044 |
| purification and characterization of cry1ac toxin binding proteins from the brush border membrane of helicoverpa armigera midgut. | several cry1ac binding proteins from midgut of helicoverpa armigera were purified using toxin-affinity chromatography. enzyme assays showed that the purified proteins had strong aminopeptidase activity. the n-terminal sequences confidently identified a 124-kda binding protein as an aminopeptidase n (apn), and some similarity suggests that a 162-kda binding protein may also be an apn. two minor binding proteins were not characterized. | 2005 | 16252132 |
| higher accumulation of proteinase inhibitors in flowers than leaves and fruits as a possible basis for differential feeding preference of helicoverpa armigera on tomato (lycopersicon esculentum mill, cv. dhanashree). | tomato (lycopersicon esculentum, mill; cultivar- dhanashree) proteinase inhibitors (pis) were tested for their trypsin inhibitory (ti) and helicoverpa armigera gut proteinases inhibitory (hgpi) activity in different organs of the tomato plants. analysis of ti and hgpi distribution in various parts of the plant showed that flowers accumulated about 300 and 1000 times higher levels of ti while 700 and 400 times higher levels of hgpi as compared to those in leaves and fruits, respectively. field ob ... | 2005 | 16256155 |
| analysis of substrate specificity and endopeptidyl activities of the cathepsin b-like proteinase from helicoverpa armigera. | the cathepsin b-like proteinase from helicoverpa armigera (hcb) is involved in the degradation of yolk proteins during embryonic development. in order to gain insight into the substrate specificity of this proteinase, various proteins from animals and plants were tested as substrates. the specific cleavage sites of this enzyme on endopeptide bonds were assayed using bovine serum albumin (bsa) as a substrate. results showed that bsa was degraded into several fragments, which suggests that hcb cle ... | 2005 | 16283544 |
| hearsnpv orf83 encodes a late, nonstructural protein with an active chitin-binding domain. | the orf83 (ha83) of helicoverpa armigera nucleopolyhedrovirus (hearsnpv) was characterized during the present study. sequence analysis and chitin-binding assay revealed that ha83 contained an active chitin-binding domain. northern blot and western blot analyses demonstrated that ha83 was expressed as a late gene and encoded a nonstructural protein of hearsnpv. ha83 gene was transcribed beginning at 12h post-infection in infected helicoverpa zea cells (hzam1). western blot analysis using a rabbit ... | 2006 | 16313991 |