| in-vitro antimicrobial, antibiofilm, cytotoxic, antifeedant and larvicidal properties of novel quinone isolated from aegle marmelos (linn.) correa. | plant metabolites have wide applications and have the potential to cure different diseases caused by microorganisms. the aim of the study was to evaluate the antimicrobial, antibiofilm, cytotoxic, antifeedant and larvicidal properties of novel quinine isolated from aegle marmelos (linn.) correa. | 2014 | 25359605 |
| a glycoprotein α-amylase inhibitor from withania somnifera differentially inhibits various α-amylases and affects the growth and development of tribolium castaneum. | identification and characterisation of plant defensive molecules enrich our resources to design crop protection strategies. in particular, plant-derived proteinaceous inhibitor(s) of insect digestive enzymes appear to be a safe, sustainable and attractive option. | 2016 | 27770482 |
| molecular docking and site-directed mutagenesis of a bacillus thuringiensis chitinase to improve chitinolytic, synergistic lepidopteran-larvicidal and nematicidal activities. | bacterial chitinases are useful in the biocontrol of agriculturally important pests and fungal pathogens. however, the utility of naturally occurring bacterial chitinases is often limited by their low enzyme activity. in this study, we constructed mutants of a bacillus thuringiensis chitinase with enhanced activity based on homology modeling, molecular docking, and the site-directed mutagenesis of target residues to modify spatial positions, steric hindrances, or hydrophilicity/hydrophobicity. w ... | 2015 | 25678849 |
| identification and characterization of the sudanese bacillus thuringiensis and related bacterial strains for their efficacy against helicoverpa armigera and tribolium castaneum. | forty-four isolates of bacillus thuringiensis like bacteria from various sources in different locations from sudan were tested for their insecticidal activity. the toxicity of these isolates ranged from 6.6 to 70% to the neonates of cotton bollworm, helicoverpa armigera at 10 ppm concentration. the most effective ones are kb-29, st-6 and wh-1 comparable with hd-1. toxicity of isolates to larvae of the red flour beetle, tribolium castaneum ranged from 20 to 100%. isolates st-2 and st-23 gave 100% ... | 2014 | 24956895 |
| 20-hydroxyecdysone transcriptionally regulates humoral immunity in the fat body of helicoverpa armigera. | 20-hydroxyecdysone (20e) increases its titre level during the wandering stage and influences innate immunity in many holometabolous insects. however, the function of 20e as an immune-activator or -suppressor needs to be determined. here, the transcriptome of the peptidoglycan-challenged fat body of the cotton bollworm, helicoverpa armigera, was analysed using illumina sequencing technology. overall, 32 073 unigenes were assembled with a mean length of 643 nucleotides. gene expression dynamics in ... | 2014 | 25224836 |
| combination of endophytic bacillus and beauveria for the management of fusarium wilt and fruit borer in tomato. | most of the approaches for biocontrol of pests and diseases have used a single biocontrol agent as antagonist to a single pest or pathogen. this accounts for the inconsistency in the performance of biocontrol agents. the development of a bioformulation possessing a mixture of bioagents could be a viable option for the management of major pests and diseases in crop plants. | 2014 | 24376014 |
| baseline susceptibility of field populations of helicoverpa armigera to bacillus thuringiensis vip3aa toxin and lack of cross-resistance between vip3aa and cry toxins. | the cotton bollworm helicoverpa armigera (hübner) is one of the most damaging cotton pests worldwide. in china, control of this pest has been dependent on transgenic cotton producing a single bacillus thuringiensis (bt) protein cry1ac since 1997. a small, but significant, increase in h. armigera resistance to cry1ac was detected in field populations from northern china. since vip3aa has a different structure and mode of action than cry proteins, bt cotton pyramids containing vip3aa are considere ... | 2017 | 28379206 |
| characteristics of resistance to bacillus thuringiensis toxin cry2ab in a strain of helicoverpa punctigera (lepidoptera: noctuidae) isolated from a field population. | in 1996, the australian cotton industry adopted ingard that expresses the bacillus thuringiensis (bt) toxin gene cry1ac and was planted at a cap of 30%. in 2004-2005, bollgard ii, which expresses cry1ac and cry2ab, replaced ingard in australia, and subsequently has made up >80% of the area planted to cotton, gossypium hirsutum l. the australian target species helicoverpa armigera (hübner) and helicoverpa punctigera (wallengren) are innately moderately tolerant to bt toxins, but the absence of a ... | 2010 | 21309238 |
| vip3aa tolerance response of helicoverpa armigera populations from a cry1ac cotton planting region. | transgenic cotton, gossypium hirsutum l., that expresses the bacillus thuringiensis (bt) cry1ac toxin, holds great promise in controlling target insect pests. evolution of resistance by target pests is the primary threat to the continued efficacy of bt cotton. to thwart pest resistance evolution, a transgenic cotton culitvar that produces two different bt toxins, cry1ac and vip3a genes, was proposed as a successor of cry1ac cotton. this article reports on levels of vip3aa tolerance in helicoverp ... | 2010 | 21309241 |
| resistance to bacillus thuringiensis toxin cry2ab and survival on single-toxin and pyramided cotton in cotton bollworm from china. | evolution of helicoverpa armigera resistance to bacillus thuringiensis (bt) cotton producing cry1ac is progressing in northern china, and replacement of cry1ac cotton by pyramided bt cotton has been considered to counter such resistance. here, we investigated four of the eight conditions underlying success of the refuge strategy for delaying resistance to cry1ac+cry2ab cotton, a pyramid that has been used extensively against h. armigera outside china. laboratory bioassays of a cry2ab-selected st ... | 2017 | 28127393 |
| bioinsecticidal activity of murraya koenigii miraculin-like protein against helicoverpa armigera and spodoptera litura. | miraculin-like proteins, belonging to the kunitz superfamily, are natural plant defense agents against pests and predators, and therefore are potential biopesticides for incorporation into pest-resistant crops. here, a miraculin-like protein from murraya koenigii was assessed for its in vitro and in vivo effects against two polyphagous lepidopteran insect pests, helicoverpa armigera and spodoptera litura. m. koenigii miraculin-like protein (mkmlp) inhibited the trypsin-like activity and total pr ... | 2011 | 21948662 |
| genetic variation and virulence of nucleopolyhedroviruses isolated worldwide from the heliothine pests helicoverpa armigera, helicoverpa zea, and heliothis virescens. | to assess the diversity and relationships of baculoviruses found in insects of the heliothine pest complex, a pcr-based method was used to classify 90 samples of nucleopolyhedrovirus (npv; baculoviridae: alphabaculovirus) obtained worldwide from larvae of heliothis virescens, helicoverpa zea, and helicoverpa armigera. partial nucleotide sequencing and phylogenetic analysis of three highly conserved genes (lef-8, lef-9, and polh) indicated that 67 of these samples contained isolates of the h. zea ... | 2011 | 21439295 |
| Putative phosphorylation sites on WCA domain of HA2 is essential for Helicoverpa armigera single nucleopolyhedrovirus replication. | Protein phosphorylation is one of the most common post-translational modification processes that play an essential role in regulating protein functionality. The Helicoverpa armigera single nucleopolyhedrovirus (HearNPV) orf2-encoded nucleocapsid protein HA2 participates in orchestration of virus-induced actin polymerization through its WCA domain, in which phosphorylation status are supposed to be critical in respect to actin polymerization. In the present study, two putative phosphorylation sit ... | 2011 | 21847755 |
| 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 |
| reproductive cost associated with juvenile hormone in bt-resistant strains of helicoverpa armigera (lepidoptera: noctuidae). | transgenic bacillus thuringiensis (bt) crops are increasingly significant in pest control, but resistance development of target pests is a major issue in the sustainable deployment of bt crops. the fitness cost of resistance in target pests is regarded as one of the main factors delaying resistance when adopting the refuge strategy. in this study, we compared the life-history traits of three independent sets of helicoverpa armigera (hübner, 1809) adults, of each there were a susceptible populati ... | 2016 | 27986942 |
| insecticidal specificity of cry1ah to helicoverpa armigera is determined by binding of apn1 via domain ii loops 2 and 3. | bacillus thuringiensis cry1ah protein is highly toxic against helicoverpa armigera but shows no toxicity against bombyx mori larvae. in contrast, the closely related cry1ai toxin showed the opposite phenotype: high activity against b. mori but no toxicity against h. armigera. analysis of binding of cry1ah to brush border membrane vesicle (bbmv) proteins from h. armigera and b. mori by surface plasmon resonance revealed association of toxin binding with insect specificity. pulldown experiments id ... | 2017 | 27940541 |
| prevalence of cry2-type genes in bacillus thuringiensis isolates recovered from diverse habitats in india and isolation of a novel cry2af2 gene toxic to helicoverpa armigera (cotton boll worm). | insecticidal cry and vip genes from bacillus thuringiensis (bt) have been used for control of lepidopteran insects in transgenic crops. however, novel genes are required for gene pyramiding to delay evolution of resistance to the currently deployed genes. two pcr-based techniques were employed for screening of cry2-type genes in 129 bt isolates from diverse habitats in india and 27 known bt strains. cry2ab-type genes were more prevalent than cry2aa- and cry2ac-type genes. correlation between sou ... | 2016 | 27805417 |
| 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 |
| isolation and characterization of gut bacterial proteases involved in inducing pathogenicity of bacillus thuringiensis toxin in cotton bollworm, helicoverpa armigera. | bacillus thuringiensis toxin proteins are deployed in transgenic plants for pest management. the present studies were aimed at characterization of gut bacterial proteases involved in activation of inactive cry1ac protoxin (pro-cry1ac) to active toxin in helicoverpa armigera. bacterial strains were isolated from h. armigera midgut and screened for their proteolytic activation toward pro-cry1ac. among 12 gut bacterial isolates seven isolates showed proteolytic activity, and proteases from three is ... | 2016 | 27766093 |
| distribution and metabolism of bt-cry1ac toxin in tissues and organs of the cotton bollworm, helicoverpa armigera. | crystal (cry) proteins derived from bacillus thuringiensis (bt) have been widely used in transgenic crops due to their toxicity against insect pests. however, the distribution and metabolism of these toxins in insect tissues and organs have remained obscure because the target insects do not ingest much toxin. in this study, several cry1ac-resistant strains of helicoverpa armigera, fed artificial diets containing high doses of cry1ac toxin, were used to investigate the distribution and metabolism ... | 2016 | 27399776 |
| bacillus thuringiensis protein cry6b (bgsc id 4d8) is toxic to larvae of hypera postica. | insecticidal proteins produced by strains of bacillus thuringenesis are specific toward target pests. one of the bt proteins, cry 1ac has been used successfully for controlling crop predation by polyphagous pests helicoverpa armigera. structurally, bt proteins consist of three domains; domain i and iii are fairly homologous in various bt proteins while domain ii is hypervariable. the hypervariable domain ii is believed to be responsible for specificity toward target pest. successful deployment o ... | 2011 | 20835830 |
| cyclic di-gmp contributes to adaption and virulence of bacillus thuringiensis through a riboswitch-regulated collagen adhesion protein. | cyclic di-gmp is a ubiquitous second messenger that regulates diverse cellular processes in bacteria by binding to various protein or riboswitch effectors. in bacillus thuringiensis bmb171, a c-di-gmp riboswitch termed bc2 rna resides in the 5'-untranslated region (5'-utr) of an mrna that encodes a collagen adhesion protein (cap). the expression of cap was strongly repressed in parent strain bmb171 because of the presence of bc2 rna but was significantly promoted in the bc2 rna markerless deleti ... | 2016 | 27381437 |
| a lysine at the c-terminus of an odorant-binding protein is involved in binding aldehyde pheromone components in two helicoverpa species. | odorant-binding proteins (obps) are soluble proteins, whose role in olfaction of insects is being recognized as more and more important. we have cloned, expressed and purified an obp (harmobp7) from the antennae of the moth helicoverpa armigera. western blot experiments indicate specific expression of this protein in the antennae of adults. harmobp7 binds both pheromone components z-11-hexadecenal and z-9-hexadecenal with good affinity. we have also performed a series of binding experiments with ... | 2013 | 23372826 |
| cross-resistance and interactions between bt toxins cry1ac and cry2ab against the cotton bollworm. | to delay evolution of pest resistance to transgenic crops producing insecticidal proteins from bacillus thuringiensis (bt), the "pyramid" strategy uses plants that produce two or more toxins that kill the same pest. we conducted laboratory diet experiments with the cotton bollworm, helicoverpa armigera, to evaluate cross-resistance and interactions between two toxins in pyramided bt cotton (cry1ac and cry2ab). selection with cry1ac for 125 generations produced 1000-fold resistance to cry1ac and ... | 2015 | 25586723 |
| proteomics analysis of helicoverpa armigera single nucleocapsid nucleopolyhedrovirus identified two new occlusion-derived virus-associated proteins, ha44 and ha100. | sodium dodecyl sulfate-polyacrylamide gel electrophoresis and mass spectrometry were used to analyze the structural proteins of the occlusion-derived virus (odv) of helicoverpa armigera single nucleocapsid nucleopolyhedrovirus (hearnpv), a group ii npv. twenty-three structural proteins of hearnpv odv were identified, 21 of which have been reported previously as structural proteins or odv-associated proteins in other baculoviruses. these include polyhedrin, p78/83, p49, odv-e18, odv-ec27, odv-e56 ... | 2007 | 17581982 |
| identification, characterization, and expression of a novel p450 gene encoding cyp6ae25 from the asian corn borer, ostrinia furnacalis. | an allele of the cytochrome p450 gene, cyp6ae14, named cyp6ae25 (genbank accession no. eu807990) was isolated from the asian com borer, ostrinia fumacalis (guenée) (lepidoptera: pyralidae) by rt-pcr. the cdna sequence of cyp6ae25 is 2315 bp in length and contains a 1569 nucleotides open reading frame encoding a putative protein with 523 amino acid residues and a predicted molecular weight of 59.95 kda and a theoretical pi of 8.31. the putative protein contains the classic heme-binding sequence m ... | 0 | 21529257 |
| next-generation sequencing-based transcriptome analysis of helicoverpa armigera larvae immune-primed with photorhabdus luminescens tt01. | although invertebrates are incapable of adaptive immunity, immunal reactions which are functionally similar to the adaptive immunity of vertebrates have been described in many studies of invertebrates including insects. the phenomenon was termed immune priming. in order to understand the molecular mechanism of immune priming, we employed illumina/solexa platform to investigate the transcriptional changes of the hemocytes and fat body of helicoverpa armigera larvae immune-primed with the pathogen ... | 2013 | 24302999 |
| cloning, characterization and expression of a novel haplotype cry2a-type gene from bacillus thuringiensis strain swk1, native to himalayan valley kashmir. | bacillus thuringiensis (bt) is a gram positive bacterium which is effectively being used in pest management strategies as an eco-friendly bioinsecticide. in the present study a new cry2a gene was cloned from a promising indigenous b. thuringiensis swk1 strain previously characterized for its toxicity against spodoptera litura and helicoverpa armigera larvae. the nucleotide sequence of the cloned cry2a gene pointed out that the open reading frame has 1902 bases encoding a polypeptide of 634 amino ... | 2016 | 26906447 |
| cloning and tissue-specific expression of a chitin deacetylase gene from helicoverpa armigera (lepidoptera: noctuidae) and its response to bacillus thuringiensis. | chitin deacetylases (cdas) convert chitin into chitosan, the n-deacetylated form of chitin, which influences the mechanical and permeability properties of structures such as the cuticle and peritrophic matrices. in this article, a new cda encoding gene, hacda2, was cloned by reverse transcription-polymerase chain reaction method in helicoverpa armigera (hübner) (lepidoptera: noctuidae), with an open reading frame of 1,611 bp. the deduced protein composed of 536 amino acid residues with a signal ... | 2015 | 26163665 |
| cantharidin impedes activity of glutathione s-transferase in the midgut of helicoverpa armigera hübner. | previous investigations have implicated glutathione s-transferases (gsts) as one of the major reasons for insecticide resistance. therefore, effectiveness of new candidate compounds depends on their ability to inhibit gsts to prevent metabolic detoxification by insects. cantharidin, a terpenoid compound of insect origin, has been developed as a bio-pesticide in china, and proves highly toxic to a wide range of insects, especially lepidopteran. in the present study, we test cantharidin as a model ... | 2013 | 23528854 |
| in-silico determination of insecticidal potential of vip3aa-cry1ac fusion protein against lepidopteran targets using molecular docking. | study and research of bt (bacillus thuringiensis) transgenic plants have opened new ways to combat insect pests. over the decades, however, insect pests, especially the lepidopteran, have developed tolerance against bt delta-endotoxins. such issues can be addressed through the development of novel toxins with greater toxicity and affinity against a broad range of insect receptors. in this computational study, functional domains of bacillus thuringiensis crystal delta-endotoxin (cry1ac) insectici ... | 2015 | 26697037 |
| proteomic analysis of the influence of cu(2+) on the crystal protein production of bacillus thuringiensis x022. | bacillus thuringiensis x022, a novel strain isolated from soil in china, produces diamond-shaped parasporal crystals. specific mineral nutrients, such as mg, cu, and mn, influence insecticidal crystal proteins (icp) expression and the effects of these elements vary significantly. however, the molecular mechanisms of the effects caused by mineral elements have yet to be reported. | 2015 | 26438125 |
| expansion of a bitter taste receptor family in a polyphagous insect herbivore. | the insect taste system plays a central role in feeding behaviours and co-evolution of insect-host interactions. gustatory receptors form the interface between the insect taste system and the environment. from genome and transcriptome sequencing we identified 197 novel gustatory receptor (gr) genes from the polyphagous pest helicoverpa armigera. these grs include a significantly expanded bitter receptor family (180 grs) that could be further divided into three categories based on polypeptide len ... | 2016 | 27032373 |
| resistance of australian helicoverpa armigera to fenvalerate is due to the chimeric p450 enzyme cyp337b3. | worldwide, increasing numbers of insects have evolved resistance to a wide range of pesticides, which hampers their control in the field and, therefore, threatens agriculture. members of the carboxylesterase and cytochrome p450 monooxygenase superfamilies are prominent candidates to confer metabolic resistance to pyrethroid insecticides. both carboxylesterases and p450 enzymes have been shown to be involved in pyrethroid resistance in australian helicoverpa armigera, the noctuid species possessi ... | 2012 | 22949643 |
| [characterization and cloning of the cry2a gene from indigenous isolates of bacillus thuringiensis]. | discovery of novel cry genes of bacillus thuringiensis (bt) with higher toxicity is important for the development of transgenic bt crops resistant to target pests. two new indigenous isolates of bt were characterized for their colony type, crystal inclusion and toxicity with helicoverpa armigera hubner and spodoptera litura linn. screening of cry2a genes from the two new isolates of bt, t30 and t48, by pcr with cry2a family primers showed the presence of cry2a genes only in the isolate t30. furt ... | 2017 | 26299858 |
| proteomic and metabolomic profiles of larval hemolymph associated with diapause in the cotton bollworm, helicoverpa armigera. | diapause is programmed developmental arrest coupled with the depression of metabolic activity and the enhancement of stress resistance. pupal diapause is induced by environmental signals and is prepared during the prediapause phase. in the cotton bollworm, helicoverpa armigera, the prediapause phase, which contains two sub-phases, diapause induction and preparation, occurs in the larval stage. here, we performed parallel proteomic and metabolomic analyses on h. armigera larval hemolymph during t ... | 2013 | 24180224 |
| identification of gene expression changes associated with the initiation of diapause in the brain of the cotton bollworm, helicoverpa armigera. | diapause, a state of arrested development accompanied by a marked decrease of metabolic rate, helps insects to overcome unfavorable seasons. helicoverpa armigera (har) undergoes pupal diapause, but the molecular mechanism of diapause initiation is unclear. using suppression subtractive hybridization (ssh), we investigated differentially expressed genes in diapause- and nondiapause-destined pupal brains at diapause initiation. | 2011 | 21569297 |
| complete genome sequence of agrotis segetum granulovirus shanghai strain. | the complete nucleotide sequence of agrotis segetum granulovirus shanghai strain (agsegv-l1) was determined and compared with that of agsegv xinjiang strain (agsegv-xj). the circular genome of agsegv-l1 is 131,442 bp and has a g+c content of 37.27 %. it includes 149 orfs, 24 of which are unique to agsegv (agsegv-l1 and agsegv-xj [genbank accession no. nc_005839]). the average level of amino acid sequence identity between agsegv-l1 and other granulovirus (gv) homologues (except agsegv-xj) ranged ... | 2014 | 24519461 |
| evaluation of total phenolic compounds and insecticidal and antioxidant activities of tomato hairy root extract. | tomatoes are one of the most consumed crops in the whole world because of their versatile importance in dietary food as well as many industrial applications. they are also a rich source of secondary metabolites, such as phenolics and flavonoids. in the present study, we described a method to produce these compounds from hairy roots of tomato (thrs). agrobacterium rhizogenes strain a4 was used to induce hairy roots in the tomato explants. the ri t-dna was confirmed by polymerase chain reaction am ... | 2014 | 24635720 |
| endogenous expression of a bt toxin receptor in the cry1ac-susceptible insect cell line and its synergistic effect with cadherin on cytotoxicity of activated cry1ac. | although many insect cell lines derived from various tissues are available, it is unclear whether endogenous receptors of bacillus thuringiensis (bt) crystal toxins are expressed in these cell lines. in the present study, we demonstrated that the ovaries-derived spodoptera litura sl-hp cell line was susceptible to activated cry1ac although larvae of s. litura are not susceptible to the toxin. assays of the transcriptome revealed that thirteen atp-binding cassette transporter genes (abc) were exp ... | 2015 | 25662100 |
| effects of site-mutations within the 22 kda no-core fragment of the vip3aa11 insecticidal toxin of bacillus thuringiensis. | bacillus thuringiensis vegetative insecticidal proteins (vips) are not homologous to other known cry proteins, and they act against lepidopteran larvae via a unique process. all reported studies on the mode of action of vip3 proteins have been performed on the vip3a family, mostly on the vip3aa subfamily. vip3aa proteins are activated by midgut proteases, and they cross the peritrophic membrane and bind specific proteins in apical membrane epithelial midgut cells, which results in pore formation ... | 2017 | 28321527 |
| cis-mediated down-regulation of a trypsin gene associated with bt resistance in cotton bollworm. | transgenic plants producing insecticidal proteins from the bacterium bacillus thuringiensis (bt) are useful for pest control, but their efficacy is reduced when pests evolve resistance. here we examined the mechanism of resistance to bt toxin cry1ac in the laboratory-selected lf5 strain of the cotton bollworm, helicoverpa armigera. this strain had 110-fold resistance to cry1ac protoxin and 39-fold resistance to cry1ac activated toxin. evaluation of five trypsin genes revealed 99% reduced transcr ... | 2014 | 25427690 |
| Compatibility of garlic (Allium sativum L.) leaf agglutinin and Cry1Ac d-endotoxin for gene pyramiding. | d-Endotoxins produced by Bacillus thuringiensis (Bt) have been used as bio-pesticides for the control of lepidopteran insect pests. Garlic (Allium sativum L.) leaf agglutinin (ASAL), being toxic to several sap-sucking pests and some lepidopteran pests, may be a good candidate for pyramiding with d-endotoxins in transgenic plants for enhancing the range of resistance to insect pests. Since ASAL shares the midgut receptors with Cry1Ac in Helicoverpa armigera, there is possibility of antagonism in ... | 2011 | 21870043 |
| Early warning of cotton bollworm resistance associated with intensive planting of Bt cotton in China. | Transgenic crops producing Bacillus thuringiensis (Bt) toxins kill some key insect pests, but evolution of resistance by pests can reduce their efficacy. The predominant strategy for delaying pest resistance to Bt crops requires refuges of non-Bt host plants to promote survival of susceptible pests. To delay pest resistance to transgenic cotton producing Bt toxin Cry1Ac, farmers in the United States and Australia planted refuges of non-Bt cotton, while farmers in China have relied on "natural" r ... | 2011 | 21857961 |
| acute, sublethal, and combination effects of azadirachtin and bacillus thuringiensis on the cotton bollworm, helicoverpa armigera. | the cotton bollworm, helicoverpa armigera hübner (lepidoptera: noctuidae) is a polyphagous and cosmopolitan insect pest that causes damage to various plants. in this study, the lethal and sublethal effects of azadirachtin and bacillus thuringiensis berliner sub sp . kurstaki (bacillales: bacillaceae) were evaluated on third instar h. armigera under laboratory conditions. the lc50 values of azadirachtin and bt were 12.95 and 96.8 µg a.i./ml, respectively. a total mortality of 56.7% was caused on ... | 2014 | 25373177 |
| isolation and characterization of baculoviruses from three major lepidopteran pests in the semi-arid tropics of india. | baculoviruses were isolated from three major lepidopteran pests, helicoverpa armigera, spodoptera litura and amsacta albistriga in the semi-arid tropics during natural epizootic conditions at icrisat fields, patancheru, andhra pradesh, india. biological, morphological and biochemical analysis identified these isolates as nucleopolyhedroviruses (npvs). scanning electron microscopy of the occlusion bodies (obs) purified from diseased larvae revealed polyhedral particles of size approximately 0.5-2 ... | 2011 | 23637499 |
| development of pod borer-resistant transgenic chickpea using a pod-specific and a constitutive promoter-driven fused cry1ab/ac gene. | we studied pod-specific msg promoter from soybean and developed different transgenic lines of chickpea expressing fused cry1ab/ac constitutively and pod specifically for resistance against the destructive pest helicoverpa armigera. crystal (cry) proteins derived from the soil bacterium bacillus thuringiensis (bt) play an important role in controlling infestation of helicoverpa armigera, which has been considered a serious problem in chickpea productivity. this study was undertaken to overcome th ... | 2014 | 25252910 |
| assessment of bt trait purity in different generations of transgenic cottons. | adequate expression of bt (bacillus thuringiensis) toxins and purity of seeds of bt-transgenic cottons are important for controlling bollworms, and thereby increasing the cotton productivity. therefore, we examined the variability in expression of bt toxin proteins in the seeds and in leaves of different cotton (gossypium hirsutum (l.) hybrids (jkch 226, jkch 1947, jkch durga, jkch ishwar, jkch varun kdchh 441 and kdchh 621) expressing bt toxins in f₁ and f₂ generations, using bioassays against ... | 2016 | 27295920 |
| activation of bt protoxin cry1ac in resistant and susceptible cotton bollworm. | crystalline (cry) proteins from bacillus thuringiensis (bt) are used extensively for insect control in sprays and transgenic plants, but their efficacy is reduced by evolution of resistance in pests. here we evaluated reduced activation of cry1ac protoxin as a potential mechanism of resistance in the invasive pest helicoverpa armigera. based on the concentration killing 50% of larvae (lc50) for a laboratory-selected resistant strain (lf120) divided by the lc50 for its susceptible parent strain ( ... | 2016 | 27257885 |
| molecular cloning, expression, and identification of bre genes involved in glycosphingolipids synthesis in helicoverpa armigera (lepidoptera: noctuidae). | glycosphingolipids (gsls) play important roles in the cellular biology of vertebrate and invertebrate organisms, such as cell differentiation, tumor metastasis, and cell coordination. gsls also serve as receptors for different bacterial toxins. for example, in the nematode caenorhabditis elegans, gsls function as receptors of the insecticidal cry toxins produced by bacillus thuringiensis (bt), and mutations in bre genes involved in gsls synthesis resulted in resistance to cry5 toxin in this orga ... | 2016 | 27190043 |
| characterization of the resistance to vip3aa in helicoverpa armigera from australia and the role of midgut processing and receptor binding. | crops expressing genes from bacillus thuringiensis (bt crops) are among the most successful technologies developed for the control of pests but the evolution of resistance to them remains a challenge. insect resistant cotton and maize expressing the bt vip3aa protein were recently commercialized, though not yet in australia. we found that, although relatively high, the frequency of alleles for resistance to vip3aa in field populations of h. armigera in australia did not increase over the past fo ... | 2016 | 27095284 |
| fitness costs of reproductive capacity and ovarian development in a bt-resistant strain of the cotton bollworm helicoverpa armigera (hübner) (lepidoptera: noctuidae). | the cotton bollworm helicoverpa armigera has developed resistance to the insecticidal cry1ac toxins produced by bacillus thuringiensis (bt) in china. to gain a better understanding of the fitness cost associated with resistance evolution, reproductive capacities and ovarian development were examined in four strains of h. armigera: a cry1ac-susceptible strain (96s); a cry1ac-resistant strain fed on an artificial diet with cry1ac toxin for 135 generations (btr); two strains derived from btr: a str ... | 2015 | 25186022 |
| resistance to bacillus thuringiensis mediated by an abc transporter mutation increases susceptibility to toxins from other bacteria in an invasive insect. | evolution of pest resistance reduces the efficacy of insecticidal proteins from the gram-positive bacterium bacillus thuringiensis (bt) used widely in sprays and transgenic crops. recent efforts to delay pest adaptation to bt crops focus primarily on combinations of two or more bt toxins that kill the same pest, but this approach is often compromised because resistance to one bt toxin causes cross-resistance to others. thus, integration of bt toxins with alternative controls that do not exhibit ... | 2016 | 26872031 |
| molecular and insecticidal characterization of vip3a protein producing bacillus thuringiensis strains toxic against helicoverpa armigera (lepidoptera: noctuidae). | vegetative insecticidal proteins (vip) represent the second generation of insecticidal proteins produced by bacillus thuringiensis (bt) during the vegetative growth stage of growth. bt-based biopesticides are recognized as viable alternatives to chemical insecticides; the latter cause environmental pollution and lead to the emergence of pest resistance. to perform a systematic study of vip genes encoding toxic proteins, a total of 30 soil samples were collected from diverse locations of kashmir ... | 2016 | 26751639 |
| elimination of gut microbes with antibiotics confers resistance to bacillus thuringiensis toxin proteins in helicoverpa armigera (hubner). | helicoverpa armigera is one of the most important pests worldwide. transgenic crops with toxin genes from bacillus thuringiensis (bt) have been deployed on a large scale to control this pest. the insecticidal activity of bt is probably influenced by the insect midgut microbes, which vary across crop hosts and locations. therefore, we examined the role of gut microbes in pathogenicity of bt toxins in the h. armigera. antibiotic cocktail was used for the complete elimination of the h. armigera gut ... | 2015 | 26384494 |
| toxicity and cross-resistance of insecticides to cry2ab-resistant and cry2ab-susceptible helicoverpa armigera and helicoverpa punctigera (lepidoptera: noctuidae). | since 2004-2005 cotton expressing cry1ac and cry2ab insecticidal proteins from the bacterium bacillus thuringiensis has been commercially available in australia to manage the target pests helicoverpa armigera (hübner) and helicoverpa punctigera (wallengren). in both target species, the frequency of alleles conferring resistance to cry2ab is unexpectedly high in field populations. a significant challenge for managing these pests would occur if resistance to cry2ab toxins inadvertently selected fo ... | 2014 | 26309283 |
| insecticidal efficacy and persistence of a co-occluded binary mixture of helicoverpa armigera nucleopolyhedrovirus (hearnpv) variants in protected and field-grown tomato crops on the iberian peninsula. | a binary co-occluded mixture (hearsp1b:lb6) of helicoverpa armigera single nucleopolyhedrovirus (hearnpv) variants was previously found to be highly pathogenic under laboratory conditions. the insecticidal efficacy and persistence of this mixture were determined in greenhouse and field-grown tomato crops in spain and portugal. | 2016 | 25960129 |
| a deletion mutant ndv200 of the bacillus thuringiensis vip3br insecticidal toxin gene is a prospective candidate for the next generation of genetically modified crop plants resistant to lepidopteran insect damage. | ectopic expression of a deletion mutant ( ndv200 ) of bacillus thuringiensis vip3br gene in tobacco plant provided almost complete protection against major crop pests cotton boll worm ( helicoverpa armigera ), black cut worm ( agrotis ipsilon ) and cotton leaf worm ( spodoptera littoralis ). whereas vip3br transgenic tobacco plant failed to protect themselves from these insects and showed resistance towards cotton leaf worm only. an analogous form of the bacillus thuringiensis vip3aa insecticida ... | 2015 | 25912191 |
| enhancement of bacillus thuringiensis insecticidal activity by combining cry1ac and bi-functional toxin hwtx-xi from spider. | in order to assess the potency of bi-functional hwtx-xi toxin from spider ornithoctonus huwena in improving the insecticidal activity of bacillus thuringiensis, a fusion gene of cry1ac and hwtx-xi was constructed and expressed in an acrystalliferous b. thuringiensis strain cry(-)b. western blot analysis and microscopic observation revealed that the recombinant strain could express 140-kda cry1ac-hwtx-xi fusion protein and produce parasporal inclusions during sporulation. bioassay using the larva ... | 2016 | 25721170 |
| next-generation transgenic cotton: pyramiding rnai and bt counters insect resistance. | transgenic crops producing insecticidal proteins from the bacterium bacillus thuringiensis (bt) are extensively cultivated worldwide. to counter rapidly increasing pest resistance to crops that produce single bt toxins, transgenic plant 'pyramids' producing two or more bt toxins that kill the same pest have been widely adopted. however, cross-resistance and antagonism between bt toxins limit the sustainability of this approach. here we describe development and testing of the first pyramids of co ... | 2017 | 28199783 |
| effects of soil salinity on the expression of bt toxin (cry1ac) and the control efficiency of helicoverpa armigera in field-grown transgenic bt cotton. | an increasing area of transgenic bacillus thuringiensis (bt) cotton is being planted in saline-alkaline soil in china. the bt protein level in transgenic cotton plants and its control efficiency can be affected by abiotic stress, including high temperature, water deficiency and other factors. however, how soil salinity affects the expression of bt protein, thus influencing the control efficiency of bt cotton against the cotton bollworm (cbw) helicoverpa armigera (hübner) in the field, is poorly ... | 2017 | 28099508 |
| draft genome sequence of bacillus thuringiensis serovar tolworthi strain na205-3, an isolate toxic for helicoverpa armigera. | we report here the complete annotated 6,510,053-bp draft genome sequence of bacillus thuringiensis serovar tolworthi strain na205-3, which is toxic for helicoverpa armigera. this strain potentially contains nine insecticidal toxin genes homologous to cry1aa12, cry1ab1, cry1ab8, cry1ba1, cry1af1, cry1ia10, vip1bb1, vip2ba2, and vip3aa6. | 2014 | 24625875 |
| a single point mutation resulting in cadherin mislocalization underpins resistance against bacillus thuringiensis toxin in cotton bollworm. | transgenic plants that produce bacillus thuringiensis (bt) crystalline (cry) toxins are cultivated worldwide to control insect pests. resistance to b. thuringiensis toxins threatens this technology, and although different resistance mechanisms have been identified, some have not been completely elucidated. to gain new insights into these mechanisms, we performed multiple back-crossing from a 3000-fold cry1ac-resistant btr strain from cotton bollworm (helicoverpa armigera), isolating a 516-fold c ... | 2017 | 28082675 |
| a screening of five bacillus thuringiensis vip3a proteins for their activity against lepidopteran pests. | five bacillus thuringiensis vip3a proteins (vip3aa, vip3ab, vip3ad, vip3ae and vip3af) and their corresponding trypsin-activated toxins were tested for their toxicity against eight lepidopteran pests: agrotis ipsilon, helicoverpa armigera, mamestra brassicae, spodoptera exigua, spodoptera frugiperda, spodoptera littoralis, ostrinia nubilalis and lobesia botrana. toxicity was first tested at a high dose at 7 and 10 days. no major differences were found when comparing protoxins vs. trypsin-activat ... | 2014 | 24508583 |
| spatio-temporal variation in landscape composition may speed resistance evolution of pests to bt crops. | transgenic crops that express insecticide genes from bacillus thuringiensis (bt) are used worldwide against moth and beetle pests. because these engineered plants can kill over 95% of susceptible larvae, they can rapidly select for resistance. here, we use a model for a pyramid two-toxin bt crop to explore the consequences of spatio-temporal variation in the area of bt crop and non-bt refuge habitat. we show that variability over time in the proportion of suitable non-bt breeding habitat, q, or ... | 2017 | 28046073 |
| activity of selected formulated biorational and synthetic insecticides against larvae of helicoverpa armigera (lepidoptera: noctuidae). | this work studied 17 insecticides belonging to nucleopolyhedrovirus (npv), bacillus thuringiensis (bt kurstaki and bt aizawai), benzoylureas (insect growth regulators [igrs]), carbamates, organophosphates, spinosyns, and diamides against larvae of helicoverpa armigera (hübner), invasive species in the south american continent. larvae of different instars were fed for 7 d with untreated or insecticide-treated diets. mortality was recorded daily for 7 d, and surviving larvae were individually weig ... | 2017 | 28011685 |
| improved insecticidal toxicity by fusing cry1ac of bacillus thuringiensis with av3 of anemonia viridis. | av3, a neurotoxin of anemonia viridis, is toxic to crustaceans and cockroaches but inactive in mammals. in the present study, av3 was expressed in escherichia coli origami b (de3) and purified by reversed-phase liquid chromatography. the purified av3 was injected into the hemocoel of helicoverpa armigera, rendering the worm paralyzed. then, av3 was expressed alone or fusion expressed with the cry1ac in acrystalliferous strain cry(-)b of bacillus thuringiensis. the shape of cry1ac was changed by ... | 2014 | 24375189 |
| characterization of parasporin gene harboring indian isolates of bacillus thuringiensis. | bacillus thuringiensis (bt) is popularly known as insecticidal bacterium. however, non-insecticidal bt strains are more extensively available in natural environment than the insecticidal ones. parasporin (ps) is a collection of genealogically heterogeneous cry proteins synthesized in non-insecticidal isolates of bt. an important character generally related with ps proteins is their strong cytocidal activity preferentially on human cancer cells of various origins. identification and characterizat ... | 2014 | 28324389 |
| synthetic fusion-protein containing domains of bt cry1ac and allium sativum lectin (asal) conferred enhanced insecticidal activity against major lepidopteran pests. | different transgenic crop plants, developed with δ-endotoxins of bacillus thuringiensis (bt) and mannose-specific plant lectins, exhibited significant protection against chewing and sucking insects. in the present study, a synthetic gene (cry-asal) encoding the fusion-protein having 488 amino acids, comprising di and dii domains from bt cry1ac and allium sativum agglutinin (asal), was cloned and expressed in escherichia coli. ligand blot analysis disclosed that the fusion-protein could bind to m ... | 2014 | 24355805 |
| insecticidal activity and histopathological effects of vip3aa protein from bacillus thuringiensis on spodoptera litura. | vegetative insecticidal proteins (vips) are insecticidal proteins synthesized by bacillus thuringiensis during the vegetative stage of growth. in this study, vip3aa protein, obtained by in vitro expression of the vip3aa gene from b. thuringiensis wb5, displayed high insecticidal activity against spodoptera litura aside from spodoptera exigua and helicoverpa armigera. bioassay results showed that the toxicity of vip3aa protein against s. litura larvae statistically decreased along with the increa ... | 2016 | 27435544 |
| high expression of cry1ac protein in cotton (gossypium hirsutum) by combining independent transgenic events that target the protein to cytoplasm and plastids. | transgenic cotton was developed using two constructs containing a truncated and codon-modified cry1ac gene (1,848 bp), which was originally characterized from bacillus thuringiensis subspecies kurstaki strain hd73 that encodes a toxin highly effective against many lepidopteran pests. in construct i, the cry1ac gene was cloned under fmvde, a strong constitutively expressing promoter, to express the encoded protein in the cytoplasm. in construct ii, the encoded protein was directed to the plastids ... | 2016 | 27391960 |
| molecular characterization of novel serovars of bacillus thuringiensis isolates from india. | novel bacillus thuringiensis isolates gs4, gn24 and up1 were isolated and characterized by determination of serotyping, insecticidal protein by sds-page, plasmid composition, cry gene content and insect toxicity. serologically two isolates gs4 and up1 were allocated to the h3abce which is a new serovar while isolate gn24 was of h3ab type. isolate gs4 produced flat crystal inclusions while up1 produced cuboidal crystals. pcr analysis found that both isolates contained cry1 and cry1ac genes. the m ... | 2012 | 23997321 |
| an improved pcr-restriction fragment length polymorphism (rflp) method for the identification of cry1-type genes. | the cry1-type genes of bacillus thuringiensis represent the largest cry gene family, which contains 50 distinct holotypes. it is becoming more and more difficult to identify cry1-type genes using current methods because of the increasing number of cry1-type genes. in the present study, an improved pcr-restriction fragment length polymorphism (pcr-rflp) method which can distinguish 41 holotypes of cry1-type genes was developed. this improved method was used to identify cry1-type genes in 20 b. th ... | 2013 | 23995930 |
| characterization of atg8 in lepidopteran insect cells. | yeast atg8 and mammalian microtubule-associated protein light chain 3 (lc3) are landmark proteins essential for autophagy. here the lepidopteran atg8, a homolog of lc3, is characterized. sequence analysis reveals that atg8 proteins are highly conserved in lepidopteran species. the abundance of endogeous atg8 and the ratios of atg8 conjugation to phosphatidylethanolamine (atg8-pe)/atg8 are different among several lepidopteran cell lines and different tissues of helicoverpa armigera larvae. both t ... | 2013 | 23959953 |
| functional validation of cadherin as a receptor of bt toxin cry1ac in helicoverpa armigera utilizing the crispr/cas9 system. | cadherins have been identified as receptors of bacillus thuringiensis (bt) cry1a toxins in several lepidopteran insects including the cotton bollworm, helicoverpa armigera. disruption of the cadherin gene hacad has been genetically linked to resistance to bt toxin cry1ac in h. armigera. by using the crispr/cas9 genome editing system (clustered regularly interspaced short palindromic repeats/crispr-associated protein 9), hacad from the cry1ac-susceptible scd strain of h. armigera was successfully ... | 2016 | 27343383 |
| heterologous expression and biochemical characterisation of fourteen esterases from helicoverpa armigera. | esterases have recurrently been implicated in insecticide resistance in helicoverpa armigera but little is known about the underlying molecular mechanisms. we used a baculovirus system to express 14 of 30 full-length esterase genes so far identified from midgut cdna libraries of this species. all 14 produced esterase isozymes after native page and the isozymes for seven of them migrated to two regions of the gel previously associated with both organophosphate and pyrethroid resistance in various ... | 2013 | 23799064 |
| stable bacillus thuringiensis transgene introgression from brassica napus to wild mustard b. juncea. | transgenic canola (brassica napus) with a bacillus thuringiensis cry1ac gene and a green fluorescent protein (gfp) marker gene was used in hybridization experiments with wild brassica juncea. hybrid f1 and successive five backcross generations were obtained. the pod-set frequency on backcrossed b. juncea plants was over 66%, which suggested relatively high crossing compatibility between the hybrids and wild species. the seed setting in bc1 was the least of all generations tested, and then increa ... | 2014 | 25219305 |
| use of a pooled clone method to isolate a novel bacillus thuringiensis cry2a toxin with activity against ostrinia furnacalis. | a pooled clone method was developed to screen for cry2a genes. this metagenomic method avoids the need to analyse isolated bacillus thuringiensis strains by performing gene specific pcr on plasmid-enriched dna prepared from a pooled soil sample. using this approach the novel holotype gene cry2ah1 was cloned and characterized. the toxin gene was over-expressed in escherichia coli rosetta (de3) and the expressed toxin accumulated in both the soluble and insoluble fractions. the soluble cry2ah1 was ... | 2013 | 23711413 |
| diversity in gut microflora of helicoverpa armigera populations from different regions in relation to biological activity of bacillus thuringiensis δ-endotoxin cry1ac. | transgenic crops expressing toxin proteins from bacillus thuringiensis (bt) have been deployed on a large scale for management of helicoverpa armigera. resistance to bt toxins has been documented in several papers, and therefore, we examined the role of midgut microflora of h. armigera in its susceptibility to bt toxins. the susceptibility of h. armigera to bt toxin cry1ac was assessed using log-dose-probit analysis, and the microbial communities were identified by 16s rrna sequencing. the h. ar ... | 2014 | 25195523 |
| characterization of cry9da4, cry9eb2, and cry9ee1 genes from bacillus thuringiensis strain t03b001. | three cry9 genes, cry9da4, cry9eb2, and cry9ee1, were cloned from bacillus thuringiensis strain t03b001 using a high-resolution melting analysis method. all three cry9 genes were overexpressed in escherichia coli rosetta (de3), and the expressed products cry9eb2 and cry9ee1 were shown to be toxic to plutella xylostella and ostrinia furnacalis, but not to helicoverpa armigera or colaphellus bowringi. the bioassay of cry9eb2 and cry9ee1 against cry1ac-resistant p. xylostella strains indicated that ... | 2013 | 23455566 |
| dual cry2ab and vip3a resistant strains of helicoverpa armigera and helicoverpa punctigera (lepidoptera: noctuidae); testing linkage between loci and monitoring of allele frequencies. | considerable attention has been given to delaying the evolution of insect resistance to toxins produced by transgenic crops. the major pests of cotton in australia are the lepidoptera helicoverpa armigera (hubner, 1805) and helicoverpa punctigera (wallengren), and the toxins deployed in current and imminent transgenic cotton varieties are cry1ac, cry2ab and vip3a from bacillus thuringiensis. in this study, lines that carry alleles conferring resistance to cry2ab and vip3a were isolated using f2 ... | 2014 | 25195454 |
| dna-based screening for an intracellular cadherin mutation conferring non-recessive cry1ac resistance in field populations of helicoverpa armigera. | a number of cadherin mutants conferring resistance to bt toxin cry1ac have been reported in three major lepidopteran pests, including helicoverpa armigera. unlike most of the cadherin mutants conferring recessive resistance, an allele (r15) with a 55aa deletion in the intracellular domain of cadherin (hacad) was previously identified to cause non-recessive resistance to cry1ac in h. armigera. in the present study, a dna-based pcr method was developed to screen the r15 allele from field populatio ... | 2013 | 25149249 |
| cloning, characterization, and expression of a new cry1ab gene from dor bt-1, an indigenous isolate of bacillus thuringiensis. | a new cry1ab gene was cloned from the promising local isolate, dor bt-1, a bacillus thuringiensis strain isolated from castor semilooper (achaea janata l.) cadavers from castor bean (ricinus communis l.) field. the nucleotide sequence of the cloned cry1ab gene indicated that the open reading frame consisted of 3,465 bases encoding a protein of 1,155 amino acid residues with an estimated molecular weight of 130 kda. homology comparisons revealed that the deduced amino acid sequence of cry1ab had ... | 2013 | 23224937 |
| cis-acting motifs in artificially synthesized expression cassette leads to enhanced transgene expression in tomato (solanum lycopersicum l.). | efficacy of artificial synthetic expression modules was compared with native camv35s and decamv35s promoter in transgenic tomato developed by agrobacterium-mediated transformation. the promoters under trial were camv35s-mec (pcami), camv35s (pcamii), decamv35s (pcamiii), synthetic minimal expression cassette (pmec), complete expression cassette (pcec), double enhancer expression cassette (pdec) and triple enhancer expression cassette (ptec) for driving the uida gene for β-glucuronidase (gus) act ... | 2012 | 23137727 |
| the halo effect: suppression of pink bollworm on non-bt cotton by bt cotton in china. | in some previously reported cases, transgenic crops producing insecticidal proteins from bacillus thuringiensis (bt) have suppressed insect pests not only in fields planted with such crops, but also regionally on host plants that do not produce bt toxins. here we used 16 years of field data to determine if bt cotton caused this "halo effect" against pink bollworm (pectinophora gossypiella) in six provinces of the yangtze river valley of china. in this region, the percentage of cotton hectares pl ... | 2012 | 22848685 |
| baseline sensitivity of maize borers in india to the bacillus thuringiensis insecticidal proteins cry1a.105 and cry2ab2. | among the major pests of maize in india are two stem borers, chilo partellus (swinhoe) and sesamia inferens (walker), and an earworm, helicoverpa armigera (hübner). as a pest control strategy, transgenic bacillus thuringiensis (bt) maize hybrids are undergoing regulatory trials in india. we have determined the sensitivity of the target lepidopterans to the insecticidal bt proteins expressed in bt maize, as this determines product efficacy and the resistance management strategy to be adopted. mai ... | 2015 | 25143318 |
| responses of 9 lepidopteran species to bacillus thuringiensis: how useful is phylogenetic relatedness for selecting surrogate species for nontarget arthropod risk assessment? | to evaluate phylogenetic relatedness as a proxy for susceptibility to bacillus thuringiensis (bt) when selecting species to act as surrogates for others in prerelease testing, we examined the responses of 11 laboratory-reared lepidopteran colonies, comprising members of 2 families, 5 genera, and 9 species, to a commercial bt preparation. survival, pupal mass, and timing of pupation and adult emergence of 2 noctuids (spodoptera litura and helicoverpa armigera) and 7 tortricids (cnephasia jactatan ... | 2015 | 25111652 |
| quantitative analysis of fitness costs associated with the development of resistance to the bt toxin cry1ac in helicoverpa armigera. | transgenic bacillus thuringiensis (bt) crops play an increasing role in pest control, and resistance management is a major issue in large-scale cultivation of bt crops. the fitness cost of resistance in targeted pests is considered to be one of the main factors delaying resistance when using the refuge strategy. by comparing 10 resistant helicoverpa armigera (hubner) strains, showing various resistance levels to bt toxin (cry1ac), to a susceptible strain, we showed an increasing fitness cost cor ... | 2014 | 25005122 |
| evaluation of the synergistic activities of bacillus thuringiensis cry proteins against helicoverpa armigera (lepidoptera: noctuidae). | with the aim of identifying cry proteins that would be useful in the management of the economically important lepidopteran pest helicoverpa armigera, the larvicidal activities of binary combinations (1:1 ratios) of six cry proteins (cry1aa, cry1ab, cry1ac, cry1ca, cry2aa and cry9aa) were evaluated against h. armigera neonate larvae using droplet feeding bioassays. determination of the ld50 values of individual cry proteins and mixtures of cry proteins enabled assessment of the nature of the inte ... | 2014 | 24963598 |
| response of last instar helicoverpa armígera larvae to bt toxin ingestion: changes in the development and in the cyp6ae14, cyp6b2 and cyp9a12 gene expression. | bt crops are able to produce cry proteins, which were originally present in bacillus thuringiensis bacteria. although bt maize is very efficient against corn borers, spanish crops are also attacked by the earworm h. armigera, which is less susceptible to bt maize. many mechanisms could be involved in this low susceptibility to the toxin, including the insect's metabolic resistance to toxins due to cytochrome p450 monooxygenases. this paper examines the response of last instar h. armigera larvae ... | 2014 | 24910993 |
| effect of different additives on the persistence and insecticidal activity of native strains of bacillus thuringiensis. | the persistence and insecticidal activity of native strains of bacillus thuringiensis was evaluated in formulations containing different additives such as arrow-root powder, carboxy methyl cellulose (cmc), gum acacia, non-food grade (nfg) starch, and soluble starch. persistence of b. thuringiensis varied with different additives used in the formulations. among the different additives used, nfg starch provided maximum protection to b. thuringiensis and native strain 42 showed maximum persistence ... | 2007 | 23100638 |
| the efficacy of beauveria bassiana, jasmonic acid and chlorantraniliprole on larval populations of helicoverpa armigera in chickpea crop ecosystems. | a robust integrated pest management (ipm) programme is needed to reduce the use of insecticides in controlling helicoverpa armigera. therefore, a 2 year field study was conducted to evaluate the use of alternative control measures (biochemical use) for h. armigera relative to exclusively using chemical insecticides. the entomopathogenic fungus beauveria bassiana, jasmonic acid and the insecticide chlorantraniliprole were each applied twice during the chickpea growing season. | 2017 | 27101405 |
| establishment and characterization of a novel cell line from midgut tissue of helicoverpa armigera (lepidoptera: noctuidae). | the midgut of lepidopteran larvae serves as a target for many pathogens such as bacillus thuringiensis (bt). cell lines originating from midgut tissues will be very helpful tools in many research fields. however, to date, no bt-susceptible midgut-derived cell lines are available. here, we reported that a novel cell line, designated as hnu-ha-mg1, was established from midgut tissue of the fourth instar larvae of helicoverpa armigera. this cell line grew well in grace's insect cell culture medium ... | 2015 | 25678461 |
| molecular cloning and characterization of α-amylase/subtilisin inhibitor from rhizome of ligusticum chuanxiong. | to clone and characterize a novel bi-functional α-amylase/subtilisin inhibitor (lasi) from the rhizome of ligusticum chuanxiong, a traditional chinese medicine. | 2017 | 27752792 |
| artificial mirna-mediated silencing of ecdysone receptor (ecr) affects larval development and oogenesis in helicoverpa armigera. | the insect pests are real threat to farmers as they affect the crop yield to a great extent. the use of chemical pesticides for insect pest control has always been a matter of concern as they pollute the environment and are also harmful for human health. bt (bacillus thuringensis) technology helped the farmers to get rid of the insect pests, but experienced a major drawback due to the evolution of insects gaining resistance towards these toxins. hence, alternative strategies are high on demand t ... | 2016 | 27476930 |
| bacterial expression and kinetic analysis of carboxylesterase 001d from helicoverpa armigera. | carboxylesterasesare an important class of detoxification enzymes involved in insecticide resistance in insects. a subgroup of helicoverpa armigera esterases, known as clade 001, was implicated in organophosphate and pyrethroid insecticide resistance due to their overabundance in resistant strains. in this work, a novel carboxylesterasegene 001d of h. armigera from china was cloned, which has an open reading frame of 1665 nucleotides encoding 554 amino acid residues. we used a series of fusion p ... | 2016 | 27049381 |
| identification of a thioredoxin peroxidase gene involved in resistance to nucleopolyhedrovirus infection in helicoverpa armigera with rna interference. | thioredoxin peroxidases (tpxs) play a crucial role in protection against oxidative damage in several insect species. however, studies on the characteristics and functions of tpxs in helicoverpa armigera are lacking. in this study, a novel 2-cys tpx gene from h. armigera (hatpx) was identified. sequence analysis revealed that hatpx is highly conserved and shares two catalysis regions (vcp) with other insect species. hatpx mrna was found to be expressed in an age-dependent manner and was ubiquitou ... | 2015 | 26238928 |
| the endoparasitoid campoletis chlorideae induces a hemolytic factor in the herbivorous insect helicoverpa armigera. | although lysis of invading organisms is a major innate form of immunity used by invertebrates, it remains unclear whether herbivorous insects have hemolysin or not. to address this general question, we tested the hemolytic (hl) activity of the hemolymph and tissue extracts from various stages of the polyphagous insect helicoverpa armigera (hübner) against the erythrocytes from chicken, duck, and rabbit. an hl activity was identified in the hemolymph of h. armigera larvae. further studies demonst ... | 2015 | 25929852 |
| rab3 is involved in cellular immune responses of the cotton bollworm, helicoverpa armigera. | rab3, a member of the rab gtpase family, has been found to be involved in innate immunity. however, the precise function of this gtpase in innate immunity remains unknown. in this study, we identified a rab3 gene (ha-rab3) from the cotton bollworm, helicoverpa armigera and studied its roles in innate immune responses. expression of ha-rab3 was upregulated in the hemocytes of h. armigera larvae after the injection of escherichia coli or chromatography beads. the dsrna-mediated knockdown of ha-rab ... | 2015 | 25662061 |
| molecular characterization of a peptidoglycan recognition protein from the cotton bollworm, helicoverpa armigera and its role in the prophenoloxidase activation pathway. | peptidoglycan recognition proteins (pgrps), which are evolutionarily conserved from invertebrates to vertebrates, function as pattern-recognition and effector molecules in innate immunity. in this study, a pgrp (hapgrp-a) from the cotton bollworm, helicoverpa armigera was identified and characterized. sequence analysis indicated that hapgrp-a is not an amidase-type pgrp. increased levels of hapgrp-a mrna were observed in the fat body and hemocytes of h. armigera larvae following the injection of ... | 2015 | 25659083 |