| isolation and identification of insect intestinal mucin haiim86--the new target for helicoverpa armigera biocontrol. | there are many more glycoproteins in helicoverpa armigera peritrophic membrane than midgut separated by sds-page analysis after periodic acid-schiff (pas) and coomassie staining. the peritrophic membrane (pm) of h. armigera larvae contains about forty associated proteins. a cdna library was constructed from h. armigera midgut mrna to study the new target for pest biocontrol. an antiserum against spodoptera exigua integral/total pm proteins cross reacted with several h. armigera pm proteins and w ... | 2011 | 21448339 |
| a eukaryotic initiation factor 5c is upregulated during metamorphosis in the cotton bollworm, helicoverpa armigera. | the orthologs of eukaryotic initiation factor 5c (eif5c) are essential to the initiation of protein translation, and their regulation during development is not well known. | 2009 | 19267937 |
| development associated profiling of chitinase and microrna of helicoverpa armigera identified chitinase repressive microrna. | expression of chitinase is developmentally regulated in insects in consonance with their molting process. during the larval-larval metamorphosis in helicoverpa armigera, chitinase gene expression varies from high to negligible. in the five-day metamorphic course of fifth-instar larvae, chitinase transcript is least abundant on third day and maximal on fifth day. microrna library prepared from these highest and lowest chitinase-expressing larval stages resulted in isolation of several mirnas. in ... | 0 | 23887392 |
| a sugar gustatory receptor identified from the foregut of cotton bollworm helicoverpa armigera. | helicoverpa armigera (hübner) is one of the most polyphagous and cosmopolitan pest species, the larvae of which feed on numerous important crops. the gustatory system is critical in guiding insect feeding behavior. here, we identified a gustatory receptor from h. armigera, hagr9, which shows high levels of identity to dmgr43a from drosophila melanogaster and bmgr9 from bombyx mori. reverse transcriptase pcr (rt-pcr) revealed hagr9 is highly expressed in larval foregut, with little or no expressi ... | 2012 | 23224441 |
| identification of micrornas in helicoverpa armigera and spodoptera litura based on deep sequencing and homology analysis. | the current identification of micrornas (mirnas) in insects is largely dependent on genome sequences. however, the lack of available genome sequences inhibits the identification of mirnas in various insect species. in this study, we used a mirna database of the silkworm bombyx mori as a reference to identify mirnas in helicoverpa armigera and spodoptera litura using deep sequencing and homology analysis. because all three species belong to the lepidoptera, the experiment produced reliable result ... | 2012 | 23289012 |
| characterization of three novel sine families with unusual features in helicoverpa armigera. | although more than 120 families of short interspersed nuclear elements (sines) have been isolated from the eukaryotic genomes, little is known about sines in insects. here, we characterize three novel sines from the cotton bollworm, helicoverpa armigera. two of them, hase1 and hase2, share similar 5' -structure including a trna-related region immediately followed by conserved central domain. the 3' -tail of hase1 is significantly similar to that of one line retrotransposon element, harte1.1, in ... | 2012 | 22319625 |
| 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 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 |
| 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 |
| candidate olfaction genes identified within the helicoverpa armigera antennal transcriptome. | antennal olfaction is extremely important for insect survival, mediating key behaviors such as host preference, mate choice, and oviposition site selection. multiple antennal proteins are involved in olfactory signal transduction pathways. of these, odorant receptors (ors) and ionotropic receptors (irs) confer specificity on olfactory sensory neuron responses. in this study, we identified the olfactory gene repertoire of the economically important agricultural pest moth, helicoverpa armigera, by ... | 2012 | 23110222 |
| 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 |
| 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 |
| in-plant protection against helicoverpa armigera by production of long hprna in chloroplasts. | expressing double-stranded rna (dsrna) in transgenic plants to silence essential genes within herbivorous pests is referred to as trans-kingdom rna interference (tk-rnai) and has emerged as a promising strategy for crop protection. however, the dicing of dsrna into sirnas by the plant's intrinsic rnai machinery may reduce this pesticidal activity. therefore, genetic constructs, encoding ∼200 nt duplex-stemmed-hairpin (hp) rnas, targeting the acetylcholinesterase gene of the cotton bollworm, heli ... | 2016 | 27746796 |
| in silico identification of cross affinity towards cry1ac pesticidal protein with receptor enzyme in bos taurus and sequence, structure analysis of crystal proteins for stability. | any novel protein introduced into the gm crops need to be evaluated for cross affinity on living organisms. many researchers are currently focusing on the impact of bacillus thuringiensis cotton on soil and microbial diversity by field experiments. in spite of this, in silico approach might be helpful to elucidate the impact of cry genes. the crystal a protein which was produced by bt at the time of sporulation has been used as a biological pesticide to target the insectivorous pests like cry1ac ... | 2013 | 24023423 |
| host plant induced variation in gut bacteria of helicoverpa armigera. | helicoverpa are important polyphagous agricultural insect pests and they have a worldwide distribution. in this study, we report the bacterial community structure in the midgut of fifth instar larvae of helicoverpa armigera, a species prevalent in the india, china, south asia, south east asia, southern & eastern africa and australia. using culturable techniques, we isolated and identified members of bacillus firmus, bacillus niabense, paenibacillus jamilae, cellulomonas variformis, acinetobacter ... | 2012 | 22292034 |
| 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 |
| transgenic pigeonpea events expressing cry1ac and cry2aa exhibit resistance to helicoverpa armigera. | independent transgenic pigeonpea events were developed using two cry genes. transgenic cry2aa-pigeonpea was established for the first time. selected transgenic events demonstrated 100% mortality of helicoverpa armigera in successive generations. lepidopteran insect helicoverpa armigera is the major yield constraint of food legume pigeonpea. the present study was aimed to develop h. armigera-resistant transgenic pigeonpea, selected on the basis of transgene expression and phenotyping. agrobacteri ... | 2017 | 28352969 |
| transgenic cotton plants expressing double-stranded rnas target hmg-coa reductase (hmgr) gene inhibits the growth, development and survival of cotton bollworms. | rna interference (rnai) has been developed as a powerful technique in the research of functional genomics as well as plant pest control. in this report, double-stranded rnas (dsrna) targeting 3-hydroxy-3-methylglutaryl coenzyme a reductase (hmgr) gene, which catalyze a rate-limiting enzymatic reaction in the mevalonate pathway of juvenile hormone (jh) synthesis in cotton bollworm, was expressed in cotton plants via agrobacterium tumefaciens-mediated transformation. pcr and sothern analysis revea ... | 2015 | 26435695 |
| comparative performance of modified full-length and truncated bacillus thuringiensis-cry1ac genes in transgenic tomato. | bt-cry1ac gene has been reputedly effective against helicoverpa armigera a notorious lepidopteran pest. reports on the expression of full-length and truncated cry1ac genes in plants for effective resistance against helicoverpa sp. have been documented however, their performance is still ambiguous. moreover, the question remains to be addressed that truncation of 3' end of the native gene was documented and suggested for active insecticidal toxin production while the most successful transgenic ev ... | 2015 | 25977893 |
| chloroplast-targeted expression of the codon-optimized truncated cry1ah gene in transgenic tobacco confers a high level of protection against insects. | the study of insect-resistant transgenic tobacco provides a good foundation for the further application of the cry1ah gene in other important crops. to improve transgene expression levels and insect resistance, the coding sequence of the novel bacillus thuringiensis insecticidal gene cry1ah (truncated cry1ah) was modified according to the codon bias of the plant by increasing its gc content from the original 37 % to 48, 55, and 63 % (designated m1-cry1ah, m2-cry1ah, and m3-cry1ah, respectively). ... | 2013 | 23620344 |
| agrobacterium-mediated transformation in chickpea (cicer arietinum l.) with an insecticidal protein gene: optimisation of different factors. | agrobacterium-mediated transformation in chickpea was developed using strain lba4404 carrying nptii, uida and cryiac genes and transformants selected on murashige and skoog's basal medium supplemented with benzyladenine, kinetin and kanamycin. integration of transgenes was demonstrated using polymerase chain reaction and southern blot hybridization of t0 plants. the expression of cryiac delta endotoxin and gus enzyme was shown by enzyme linked immunosorbent assay and histochemical assay respecti ... | 2010 | 23572977 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| [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 |
| 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 |
| 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 |
| 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 |
| large-scale test of the natural refuge strategy for delaying insect resistance to transgenic bt crops. | the 'natural refuge strategy" for delaying insect resistance to transgenic cotton that produces insecticidal proteins from bacillus thuringiensis (bt) relies on refuges of host plants other than cotton that do not make bt toxins. we tested this widely adopted strategy by comparing predictions from modeling with data from a four-year field study of cotton bollworm (helicoverpa armigera) resistance to transgenic cotton producing bt toxin cry1ac in six provinces of northern china. bioassay data rev ... | 2015 | 25503384 |
| 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 |
| expression of recombinant and mosaic cry1ac receptors from helicoverpa armigera and their influences on the cytotoxicity of activated cry1ac to spodoptera litura sl-hp cells. | bacillus thuringiensis (bt) toxin receptors play important roles in the killing of pests, and investigation on characterization of the receptors is essential for utilization of bt and management of insect resistance. here, recombinant and mosaic receptors of bt cry1ac toxin from helicoverpa armigera were expressed in spodoptera litura sl-hp cells and their influences on cytotoxicity of activated cry1ac toxin were investigated. when h. armigera aminopeptidase n1 (apn1), alkaline phosphatase 2 (al ... | 2016 | 25412589 |
| molecular and insecticidal characterization of a novel cry-related protein from bacillus thuringiensis toxic against myzus persicae. | this study describes the insecticidal activity of a novel bacillus thuringiensis cry-related protein with a deduced 799 amino acid sequence (~89 kda) and ~19% pairwise identity to the 95-kda-aphidicidal protein (sequence number 204) from patent us 8318900 and ~40% pairwise identity to the cancer cell killing cry proteins (parasporins cry41ab1 and cry41aa1), respectively. this novel cry-related protein contained the five conserved amino acid blocks and the three conserved domains commonly found i ... | 2014 | 25384108 |
| 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 |
| densovirus is a mutualistic symbiont of a global crop pest (helicoverpa armigera) and protects against a baculovirus and bt biopesticide. | mutualistic associations between symbiotic bacteria and their hosts are common within insect systems. however, viruses are often considered as pathogens even though some have been reported to be beneficial to their hosts. herein, we report a novel densovirus, helicoverpa armigera densovirus-1 (hadnv-1) that appears to be beneficial to its host. hadnv-1 was found to be widespread in wild populations of h. armigera adults (>67% prevalence between 2008 and 2012). in wild larval populations, there w ... | 2014 | 25357125 |
| 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 |
| cadherin mutation linked to resistance to cry1ac affects male paternity and sperm competition in helicoverpa armigera. | several lepidopteran pests of cotton have cadherin-based resistance to the bacillus thuringiensis (bt) toxin cry1ac. cadherins are transmembrane proteins that mediate cell-cell adhesion and tissue morphogenesis, suggesting that fitness costs associated with cadherin mutations may be present in many aspects of life history. to evaluate whether cadherin-based resistance is associated with fitness costs reducing male paternity in helicoverpa armigera, we examined the effects of a major cadherin res ... | 2014 | 25220924 |
| 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 |
| 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 |
| 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 |
| 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 |
| mis-splicing of the abcc2 gene linked with bt toxin resistance in helicoverpa armigera. | toxins from the bacterium bacillus thuringiensis (bt) are used widely for insect control in sprays and transgenic plants, but their efficacy is reduced when pests evolve resistance. previous work showed that mutations in a gene encoding the transporter protein abcc2 are linked with resistance to bt toxins cry1ab, cry1ac or both in four species of lepidoptera. here we compared the abcc2 gene of helicoverpa armigera (haabcc2) between susceptible strains and a laboratory-selected strain with >1,000 ... | 2014 | 25154974 |
| 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 |
| 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 |
| pirb-cry2aa hybrid protein exhibits enhanced insecticidal activity against spodoptera exigua larvae. | previous study revealed that the n-terminal region of pirb toxin from photorhabdus luminescens showed 20.5% identity and 41.5% similarity to the domain i of cry2a toxin of bacillus thuringiensis. the encoding sequence of the domain i of cry2aa protein was replaced by the encoding gene of corresponding domain of pirb protein. expression of pirb-cry2aa chimeric gene in b. thuringiensis acrystalliferous strain cry(-)b leads to the formation of crystals with irregular shape. bioassay showed that pir ... | 2014 | 24879991 |
| monitoring cotton bollworm resistance to cry1ac in two counties of northern china during 2009-2013. | transgenic cotton that expresses a gene derived from the bacterium bacillus thuringiensis (bt) has been deployed for combating cotton bollworm in china since 1997. as a follow-up on research started in 2002, the quantitative shifts in larval cry1ac resistance of field helicoverpa armigera populations were monitored from 2009-2013 using bioassays of isofemale lines. | 2015 | 24753356 |
| 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 |
| tradeoff between reproduction and resistance evolution to bt-toxin in helicoverpa armigera: regulated by vitellogenin gene expression. | evolution of resistance to insecticides usually has fitness tradeoffs associated with adaptation to the stress. the basic regulation mechanism of tradeoff between reproduction and resistance evolution to bacillus thuringiensis (bt) toxin in the cotton bollworm, helicoverpa armigera (ha), based on the vitellogenin (vg) gene expression was analyzed here. the full-length cdna of the vg gene havg (jx504706) was cloned and identified. havg has 5704 base pairs (bp) with an open reading frame (orf) of ... | 2014 | 24555504 |
| 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 |
| dominant resistance to bt cotton and minor cross-resistance to bt toxin cry2ab in cotton bollworm from china. | evolution of resistance by insect pests threatens the long-term benefits of transgenic crops that produce insecticidal proteins from bacillus thuringiensis (bt). previous work has detected increases in the frequency of resistance to bt toxin cry1ac in populations of cotton bollworm, helicoverpa armigera, from northern china where bt cotton producing cry1ac has been grown extensively for more than a decade. confirming that trend, we report evidence from 2011 showing that the percentage of individ ... | 2013 | 24478804 |
| coexpression of the silent cry2ab27 together with cry1 genes in bacillus thuringiensis subsp. aizawai sp41 leads to formation of amorphous crystal toxin and enhanced toxicity against helicoverpa armigera. | the unexpressed cry2ab27 gene of bacillus thuringiensis subsp. aizawai sp41 (sp41) consists of a single open reading frame (orf) of 1902bp encoding for 634 amino acid residues. the cry2ab27 gene appears to be silent due to the lack of promoter and terminator sequences. in this study we fused the cry2ab27 orf with the cry1ab promoter (500bp) and the terminator (300bp) in vector pht304-18z in order to drive the expression of cry2ab27 in both sp41 and an acrystaliferous, b. thuringiensis subsp. thu ... | 2014 | 24412546 |
| 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 |
| up-regulated death-associated lim-only protein contributes to fitness costs of bacillus thuringiensis cry1ac resistance in helicoverpa armigera. | the evolution of bacillus thuringiensis (bt) resistance provides a useful pathway for the study of fitness trade-offs associated with stress adaptation. in a previous study, we used cdna-amplification fragment length polymorphism (cdna-alfp) analysis to identify differentially expressed genes (degs) in cry1ac-susceptible (96s) and -resistant (bt-r) helicoverpa armigera larvae. among these degs, a death-associated lim-only protein (hadalp) was identified. in the current study, the full-length cdn ... | 2014 | 24326206 |
| isolation of an orally active insecticidal toxin from the venom of an australian tarantula. | many insect pests have developed resistance to existing chemical insecticides and consequently there is much interest in the development of new insecticidal compounds with novel modes of action. although spiders have deployed insecticidal toxins in their venoms for over 250 million years, there is no evolutionary selection pressure on these toxins to possess oral activity since they are injected into prey and predators via a hypodermic needle-like fang. thus, it has been assumed that spider-veno ... | 2013 | 24039872 |
| 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 |
| effect of larvae treated with mixed biopesticide bacillus thuringiensis-abamectin on sex pheromone communication system in cotton bollworm, helicoverpa armigera. | third instar larvae of the cotton bollworm (helicoverpa armigera) were reared with artificial diet containing a bacillus thuringiensis-abamectin (bta) biopesticide mixture that resulted in 20% mortality (ld20). the adult male survivors from larvae treated with bta exhibited a higher percentage of "orientation" than control males but lower percentages of "approaching" and "landing" in wind tunnel bioassays. adult female survivors from larvae treated with bta produced higher sex pheromone titers a ... | 2013 | 23874751 |
| 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 |