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[septicaemia of chironomid larvae (diptera: chironomidae) promoted by bacillus cereus and b. thuringiensis].natural factors regulating the population of chironomids were studied. the bacteria bacillus cereus were isolated from chironomids sampled from kuyalnitskii firth after epizooty of chironomus sp., and bacteria bacillus thuringiensis spp. israelensis (bti) were isolated from dead larva of chironomus plumosus sampled in the sea of azov (3-m depth). bti were characterized by high insecticide activity on midges anopheles messeae fall., aedes cireneus mg., and culex pipiens pipiens f. pipiens l.201622988756
microbial ecology and association of bacillus thuringiensis in chicken feces originating from feed.to explain the association of bacillus thuringiensis (bt) with animal feces, an ecological analysis in chickens was conducted by introducing a cry(-) strain marked by production of green fluorescent protein (gfp). after feeding with the tagged bt strains, the feces of the tested chickens were collected at different times, isolated, and the morphology of bt was observed. it was shown that bt strain hd-73gfp in spore form could be isolated from feces of chickens for a period of 13 d, and then it d ...201222986821
deep sequencing of the transcriptomes of soybean aphid and associated endosymbionts.the soybean aphid has significantly impacted soybean production in the u.s. transcriptomic analyses were conducted for further insight into leads for potential novel management strategies.201222984624
microbial control of the cotton leafworm spodoptera littoralis (boisd.) by egyptian bacillus thuringiensis isolates.four local bacillus thuringiensis (bt) isolates that had been serologically identified as bt var. kurstaki (btk2, btk3, and btk66) and bt var. mexicanensis (btm27), in addition to two reference strains (4d20 and 4ac1), were laboratory assayed as microbial control agents against the egyptian cotton leafworm spodoptera littoralis (boisd.). polymerase chain reaction (pcr) amplification analysis revealed that each of the six experimental strains carries, at least, a cry1 type gene which expresses a ...201322983675
in vitro cr(vi) reduction by cell-free extracts of chromate-reducing bacteria isolated from tannery effluent irrigated soil.four efficient cr(vi)-reducing bacterial strains were isolated from rhizospheric soil of plants irrigated with tannery effluent and investigated for in vitro cr(vi) reduction. based on 16s rrna gene sequencing, the isolated strains sucr44, sucr140, sucr186, and sucr188 were identified as bacillus sp. (jn674188), microbacterium sp. (jn674183), bacillus thuringiensis (jn674184), and bacillus subtilis (jn674195), respectively. all four isolates could completely reduce cr(vi) in culture media at 0.2 ...201322983604
isolation of single chain variable fragment (scfv) specific for cry1c toxin from human single fold scfv libraries.as bioinsecticides bacillus thuringiensis cry1c δ-endotoxins also have been used in genetically modified crops worldwide since last century. in this study, single chain variable fragments (scfvs), which could specifically recognize and detect cry1c in food samples, were isolated from naive phage displayed human antibody libraries (tomlinson i + j) by iterative affinity selection procedure instead of immunization process. with increasing selection pressure, after four rounds of panning, three ind ...201222982116
development of dipsticks for simultaneous detection of vip3a and cry1ab/cry1ac transgenic proteins.the number of genetically modified (gm) crops being cultivated and its produce reaching market is increasing every year. the transgenes (vip3a, cry1ab, and cry1ac) from bacillus thuringiensis are being used by plant breeders, apart from other transgenes for developing insect pest-resistant gm crops. it is therefore necessary to develop an easy, rapid, and reliable detection assay to discriminate gm crops and non-gm crops. dipstick strips using colloidal gold-labeled polyclonal antibodies were de ...201222970582
insecticide substitutes for ddt to control mosquitoes may be causes of several diseases.malaria continues to be a public health problem in bangladesh, despite efforts in the 1960s to eradicate the vectors through the use of ddt. at one point, eradication of malaria was acclaimed but later on it reappeared. the use of ddt is no more legally allowed in bangladesh, which has been officially replaced by a number organophosphates and/or synthetic pyrethroids and their combinations in addition to the integrated vector management (ivm) package. ivm being a community approach is still to g ...201222956113
characterization of cdnas encoding serine proteases and their transcriptional responses to cry1ab protoxin in the gut of ostrinia nubilalis larvae.serine proteases, such as trypsin and chymotrypsin, are the primary digestive enzymes in lepidopteran larvae, and are also involved in bacillus thuringiensis (bt) protoxin activation and protoxin/toxin degradation. we isolated and sequenced 34 cdnas putatively encoding trypsins, chymotrypsins and their homologs from the european corn borer (ostrinia nubilalis) larval gut. our analyses of the cdna-deduced amino acid sequences indicated that 12 were putative trypsins, 12 were putative chymotrypsin ...201222952884
evolution and the microbial control of insects.insect pathogens can be utilized in a variety of pest management approaches, from inundative release to augmentation and classical biological control, and microevolution and the consideration of evolutionary principles can potentially influence the success of all these strategies. considerable diversity exists in natural entomopathogen populations and this diversity can be either beneficial or detrimental for pest suppression, depending on the pathogen and its mode of competition, and this shoul ...201222949921
qualitative analysis of the fluorophosphonate-based chemical probes using the serine hydrolases from mouse liver and poly-3-hydroxybutyrate depolymerase (phaz) from bacillus thuringiensis.the serine hydrolase family consists of more than 200 members and is one of the largest enzyme families in the human genome. although up to 50 % of this family remains unannotated, there are increasing evidences that activities of certain serine hydrolases are associated with diseases like cancer neoplasia, invasiveness, etc. by now, several activity-based chemical probes have been developed and are applied to profile the global activity of serine hydrolases in diverse proteomes. in this study, ...201222941070
mathematical relationships between spore concentrations, delta-endotoxin levels, and entomotoxicity of bacillus thuringiensis preparations produced in different fermentation media.mathematic relationships between spore concentrations, delta-endotoxin concentrations and entomotoxicity (tx) of bacillus thuringiensis var. kurstaki hd-1 (btk hd-1) preparations produced in six different media were analysed. the relationship between delta-endotoxin and spore concentration and sptx-spore (specific tx per 1000 spore) and spore concentration produced in the different media (starch industry wastewater (siw) with total solids (ts) concentration of 15g/l, siw with ts of 30g/l, siw su ...201222940334
observations on house fly larvae midgut ultrastructure after brevibacillus laterosporus ingestion.the pathological and histopathological course caused by brevibacillus laterosporus on house fly larvae has been investigated conducting observations on insect behavior and midgut ultrastructure. after dissection and fixation, gut tissues were analyzed under transmission electron microscopy (tem) in order to compare in vivo-treated and non-treated (control) fly specimens. treated larvae showed extensively reduced feeding and growth rate, then became sluggish and died within 72 h. a progressive mi ...201222935249
adaptation by western corn rootworm (coleoptera: chrysomelidae) to bt maize: inheritance, fitness costs, and feeding preference.we examined inheritance of resistance, feeding behavior, and fitness costs for a laboratory-selected strain of western corn rootworm, diabrotica virgifera virgifera leconte (coleoptera: chrysomelidae), with resistance to maize (zea maize l.) producing the bacillus thuringiensis berliner (bt) toxin cry3bb1. the resistant strain developed faster and had increased survival on bt maize relative to a susceptible strain. results from reciprocal crosses of the resistant and susceptible strains indicate ...201222928323
western corn rootworm larval movement in smartstax seed blend scenarios.insect resistance management (irm) can extend the lifetime of management options, but depends on extensive knowledge of the biology of the pest species involved for an optimal plan. recently, the environmental protection agency (epa) registered seed blends refuge for two of the transgenic bacillus thuringiensis (bt) corn products targeting the western corn rootworm, diabrotica virgifera virgifera leconte. larval movement between bt and isoline plants can be detrimental to resistance management f ...201222928304
dispersal behavior of neonate european corn borer (lepidoptera: crambidae) on bt corn.european corn borer, ostrinia nubilalis (hübner) (lepidoptera: crambidae), has historically been a significant economically important insect pest of corn (zea mays l.) in the united states and canada. the development in the 1990s of genetically modified corn expressing genes derived from bacillus thuringiensis (bt) that encodes insecticidal crystalline (cry) proteins has proven to be effective in controlling this insect as well as other corn pests. the purpose of this study was to assess the mov ...201222928300
the utility of camptothecin as a synergist of bacillus thuringiensis var. kurstaki and nucleopolyhedroviruses against trichoplusia ni and spodoptera exigua.we studied the effect of combining microbial pesticides with camptothecin (cpt) on the mortality of two lepidopteran insects: trichoplusia ni (hübner) and spodoptera exigua (hübner). cpt is an alkaloid that is often used as an anticancer agent. here, cpt was evaluated as a microbial pesticide synergist of bacillus thuringiensis (bt) and insect baculovirus. the toxicity of cpt and its synergistic effects on two microbial pesticides were studied using the diet overlay method. bioassay results show ...201222928294
acute toxicities and sublethal effects of some conventional insecticides on trichogramma chilonis (hymenoptera: trichogrammatidae).the acute toxicity of 10 conventional insecticides to adult of trichogramma chilonis ishii (hymenoptera: trichogrammatidae) was bioassayed by membrane method, and then their sublethal effects on the parasitoid were evaluated in the laboratory. based on sublethal concentration (lc30) values at 8 h after treatment, we determined that adult t. chilonis were the most susceptible to chlorfenapyr, followed by fipronil, spinosad, avermectins, beta-cypermethrin, and cartap, with lethal concentration (lc ...201222928293
expanding the use of a fluorogenic method to determine activity and mode of action of bacillus thuringiensis bacteriocins against gram-positive and gram-negative bacteria.previously we described a rapid fluorogenic method to measure the activity of five bacteriocins produced by mexican strains of bacillus thuringiensis against b. cereus 183. here we standardize this method to efficiently determine the activity of bacteriocins against both gram-positive and gram-negative bacteria. it was determined that the crucial parameter required to obtain reproducible results was the number of cells used in the assay, that is, ~4 × 10(8) cell/ml and ~7 × 10(8) cell/ml, respec ...201222919330
screening and identification of a bacillus thuringiensis strain s1/4 with large and efficient insecticidal activities.the bacterium bacillus thuringiensis was recognized for its entomopathogenic activities related to cry and cyt proteins forming the δ-endotoxins and some extracellular activities like the vegetative insecticidal proteins (vip) and cry1i. these activities may act specifically against diverse organisms and some of them typically characterize each strain. here, we screened a set of 212 b. thuringiensis strains to search the higher insecticidal activities. these strains had bipyramidal and cubic cry ...201322915162
test method development to evaluate hot, humid air decontamination of materials contaminated with bacillus anthracis ∆sterne and b. thuringiensis al hakam spores.to develop test methods and evaluate the survival of bacillus anthracis ∆sterne and bacillus thuringiensis al hakam spores after exposure to hot, humid air.201222897143
inheritance, stability, and dominance of cry resistance in culex quinquefasciatus (diptera: culicidae) selected with the three cry toxins of bacillus thuringiensis subsp. israelensis.mendelian crosses were used to study the mode of inheritance of cry toxin resistance in a culex quinquefasciatus say (diptera: culicidae) colony (cqab11a) that evolved insecticide resistance under laboratory selection with a deletion mutant of bacillus thuringiensis subsp. israelensis de barjac lacking the cyt1aa toxin component but containing its three major cry toxins, cry4aa, cry4ba, and cry11aa. high levels of resistance were observed to cry toxins. f1 offspring of reciprocal crosses to a se ...201222897049
the lack of effect of low temperature and high turbidity on operational bacillus thuringiensis subsp. israelensis activity against larval black flies (diptera: simuliidae).black fly suppression programs are conducted across a wide range of environmental conditions, targeting a variety of pest species with diverse life histories. operational applications of vectobac 12as (bacillus thuringiensis subsp. israelensis) were conducted during times characterized by water temperature and turbidity extremes. applications were conducted in the yellow river in central wisconsin targeting simulium annulus and s. johannseni when water temperatures were 1-2 degrees c. applicatio ...201222894128
heliothis virescens and bt cotton in the united states.the tobacco budworm (tbw), heliothis virescens (f.), has been responsible for substantial economic losses, environmental pollution and a great challenge to the united states' economy, environment, researchers and cotton and tobacco producers during most of the past two hundred years. if a historical description of this pest problem should be written, it would necessarily be divided into two main events; the pre- and post-bacillus thuringiensis-expressing (bt)-cotton era. before the advent of bt- ...201422892654
deltamethrin-induced genotoxicity and testicular injury in rats: comparison with biopesticide.deltamethrin is a synthetic pyrethroid insecticide used extensively in pest control. aim of the current study was to investigate the ability of deltamethrin-based commercial formulation to induce genotoxicity and testicular injury in rats in comparison to the use of the biopesticide; bacillus thuringiensis. rats were divided into three groups: group i (del) received deltamethrin, 5 mg/kgb.w./day orally, in corn oil. group ii (biopesticide, b. thuringiensis) received oral suspension of the biopes ...201222889898
testing potential effects of maize expressing the bacillus thuringiensis cry1ab endotoxin (bt maize) on mycorrhizal fungal communities via dna- and rna-based pyrosequencing and molecular fingerprinting.the cultivation of genetically modified (gm) crops has increased significantly over the last decades. however, concerns have been raised that some gm traits may negatively affect beneficial soil biota, such as arbuscular mycorrhizal fungi (amf), potentially leading to alterations in soil functioning. here, we test two maize varieties expressing the bacillus thuringiensis cry1ab endotoxin (bt maize) for their effects on soil am fungal communities. we target both fungal dna and rna, which is new f ...201222885748
functional significance of membrane associated proteolysis in the toxicity of bacillus thuringiensis cry3aa toxin against colorado potato beetle.bacillus thuringiensis cry toxins are widely used as biocontrol agents in bioinsecticides and transgenic plants. in the three domain-cry toxins, domain ii has been identified as an important determinant of their highly specific activity against insects. in this work, we assessed the role in membrane associated proteolysis and toxicity in colorado potato beetle (cpb) of a previously reported adam recognition motif present in cry3aa toxin domain ii. we used site-directed mutagenesis to modify the ...201222884605
development of a high-resolution melting-based approach for efficient differentiation among bacillus cereus group isolates.strains belonging to bacillus cereus group include six different species, among which are bacillus thuringiensis, bacillus weihenstephanensis, and bacillus cereus sensu stricto, a causative agent of food poisoning. sequence of the panc-housekeeping gene is used for b. cereus group affiliation to seven major phylogenetic groups (i-vii) with different ecological niches and variations in thermal growth range and spore heat resistance of b. cereus group microorganisms varies among phylogenetic group ...201222881064
cytolytic peptide fragments of cyt1aa from bacillus thuringiensis subsp. israelensis.cyt1aa is the major and most active component of the parasporal crystal of the gram-positive soil entomopathogenic bacterium bacillus thuringiensis subsp. israelensis. the cyt1aa protoxin exhibits some hemolytic and cytolytic activity. however, highly active 22-25 kda toxins are obtained after proteolysis of cyt1aa from both the n- and the c-termini. as shown in this study, preliminary binding of the protoxin to polylamellary liposomes or partial denaturation of cyt1aa and further processing by ...201322875467
ser-substituted mutations of cys residues in bacillus thuringiensis vip3aa7 exert a negative effect on its insecticidal activity.vegetative insecticidal proteins (vips), which were produced by bacillus thuringiensis during its vegetative growth stage, display a broad insecticidal spectrum to lepidoptera larvae. sequence alignment of the vip3a-type indicates that three cysteine residues were conserved in vip3a-type proteins. to determine whether these conserved cysteine residues contributed to the insecticidal activity, the three residues were respectively substituted with serine in the vip3aa7 protein by site-directed mut ...201222875104
improvement of crystal solubility and increasing toxicity against caenorhabditis elegans by asparagine substitution in block 3 of bacillus thuringiensis crystal protein cry5ba.the crystal proteins from bacillus thuringiensis are widely used for their specific toxicity against insects and nematodes. the highly conserved sequence blocks play an important role in cry protein stability and flexibility, the basis of toxicity. the block 3 in cry5ba subfamily has a shorter sequence (only 12 residues) and more asparagine residues than that of others which harbor about 48 residues but only one asparagine. based on the theoretical structure model of cry5ba, all three asparagine ...201222865071
vip3c, a novel class of vegetative insecticidal proteins from bacillus thuringiensis.three vip3 genes were identified in two bacillus thuringiensis spanish collections. sequence analysis revealed a novel vip3 protein class (vip3c). preliminary bioassays of larvae from 10 different lepidopteran species indicated that vip3ca3 caused more than 70% mortality in four species after 10 days at 4 μg/cm(2).201222865065
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 ...201222848685
filament formation of the ftsz/tubulin-like protein tubz from the bacillus cereus pxo1 plasmid.stable maintenance of low-copy-number plasmids requires partition (par) systems that consist of a nucleotide hydrolase, a dna-binding protein, and a cis-acting dna-binding site. the ftsz/tubulin-like gtpase tubz was identified as a partitioning factor of the virulence plasmids pbtoxis and pxo1 in bacillus thuringiensis and bacillus anthracis, respectively. tubz exhibits high gtpase activity and assembles into polymers both in vivo and in vitro, and its "treadmilling" movement is required for pla ...201222847006
production of the 14c-labeled insecticidal protein cry1ab for soil metabolic studies using a recombinant escherichia coli in small-scale batch fermentations.insecticidal cry proteins naturally produced by bacillus thuringiensis are a major recombinant trait expressed by genetically modified crops. they are released into the soil during and after cropping. the objective of this study was to produce (14)c-labeled cry1ab proteins for soil metabolic studies in scope of their environmental risk assessment. cry1ab was synthesized as a protoxin by escherichia coli hb101 pmp in 200-ml liquid batch culture fermentations and purified from inclusion bodies aft ...201222846901
identification of a calmodulin-binding site within the domain i of bacillus thuringiensis cry3aa toxin.bacillus thuringiensis cry3aa toxin is a coleopteran specific toxin highly active against colorado potato beetle (cpb).we have recently shown that cry3aa toxin is proteolytically cleaved by cpb midgut membrane associated metalloproteases and that this cleavage is inhibited by adam metalloprotease inhibitors. in the present study, we investigated whether the cry3aa toxin is a calmodulin (cam) binding protein, as it is the case of several different adam shedding substrates. in pull-down assays usi ...201222836907
isolation and molecular characterisation of alkaline protease producing bacillus thuringiensis.proteases are of particular interest because of their action on insoluble keratin substrates and generally on a broad range of protein substrates. proteases are one of the most important groups of industrial enzymes used in detergent, protein, brewing, meat, photographic, leather, dairy, pharmaceutical and food industry. in the present study, the organism isolated from the protein rich soil sample was identified by biochemical and molecular characterisation as bacillus thuringiensis and further ...201322826099
toxins for transgenic resistance to hemipteran pests.the sap sucking insects (hemiptera), which include aphids, whiteflies, plant bugs and stink bugs, have emerged as major agricultural pests. the hemiptera cause direct damage by feeding on crops, and in some cases indirect damage by transmission of plant viruses. current management relies almost exclusively on application of classical chemical insecticides. while the development of transgenic crops expressing toxins derived from the bacterium bacillus thuringiensis (bt) has provided effective pla ...201222822455
high-salt stress conditions increase the paw63 transfer frequency in bacillus thuringiensis.conjugation experiments with bacillus thuringiensis and transfer kinetics demonstrated that salt stress has a positive impact on plasmid transfer efficiency. compared to standard osmotic conditions (0.5% nacl), plasmid transfer occurred more rapidly, and at higher frequencies (>100-fold), when bacteria were exposed to a high-salt stress (5% nacl) in liquid brain heart infusion (bhi). under milder salt conditions (2.5% nacl), only a 10-fold effect was observed in luria-bertani broth and no differ ...201222820331
novel bacteriophages containing a genome of another bacteriophage within their genomes.a novel bacteriophage infecting staphylococus pasteuri was isolated during a screen for phages in antarctic soils. the phage named spaa1 is morphologically similar to phages of the family siphoviridae. the 42,784 bp genome of spaa1 is a linear, double-stranded dna molecule with 3' protruding cohesive ends. the spaa1 genome encompasses 63 predicted protein-coding genes which cluster within three regions of the genome, each of apparently different origin, in a mosaic pattern. in two of these regio ...201222815791
effects of entomopathogenic nematodes on evolution of pink bollworm resistance to bacillus thuringiensis toxin cry1ac.the evolution of resistance by pests can reduce the efficacy of transgenic crops that produce insecticidal toxins from bacillus thuringiensis (bt). however, fitness costs may act to delay pest resistance to bt toxins. meta-analysis of results from four previous studies revealed that the entomopathogenic nematode steinernema riobrave (rhabditida: steinernematidae) imposed a 20% fitness cost for larvae of pink bollworm, pectinophora gossypiella (saunders) (lepidoptera: gelechiidae), that were homo ...201222812141
effect of temperature on the fitness of a vip3a resistant population of heliothis virescens (lepidoptera: noctuidae).microbial insecticides derived from the soil bacterium bacillus thuringiensis (bt) have become increasingly important for pest management. in addition to crystal (cry) insecticidal protein toxins formed during sporulation, vegetative insecticidal protein (vip) toxins can be produced during the vegetative phase. resistance to cry toxins has been reported in laboratory- and field-selected populations of various lepidoptera species and several studies have identified fitness costs associated with c ...201222812137
delaying corn rootworm resistance to bt corn.transgenic crops producing bacillus thuringiensis (bt) toxins for insect control have been successful, but their efficacy is reduced when pests evolve resistance. to delay pest resistance to bt crops, the u.s. environmental protection agency (epa) has required refuges of host plants that do not produce bt toxins to promote survival of susceptible pests. such refuges are expected to be most effective if the bt plants deliver a dose of toxin high enough to kill nearly all hybrid progeny produced b ...201222812111
the effectiveness of trypsin modulating oostatic factor (tmof) and combination of tmof with bacillus thuringiensis against aedes aegypti larvae in the laboratory.trypsin modulating oostatic factor (tmof) terminates trypsin biosynthesis in adult and larval mosquito gut. it will inhibit the growth and development of mosquito larvae feeding on it resulting in death by starvation. the objective of this study is to determine the effective dose of pichia-tmof and the combination of pichia-tmof with bacillus thuringiensis (bt) as larvicide on ae. aegypti larvae.201122808406
evaluation of rhizospheric pseudomonas and bacillus as biocontrol tool for xanthomonas campestris pv campestris.xanthomonas campestris pv campestris (xcc), causing black rot, is one of the most yield-limiting and destructive pathogens of cruciferous crops. the intention of this study was to evaluate the potential of rhizobacteria in black rot management. fifty-four isolates from rhizosphere soil of brassica campestris were screened against xcc. two isolates namely, ka19 and se, with inhibition radius >11 mm were selected. the combined use of them produced an average inhibition zone of 18.1 ± 1.4 mm radius ...201222806865
preliminary comparing the toxicities of the hybrid cry1acs fused with different heterogenous genes provided guidance for the fusion expression of cry proteins.in order to provide guidance for selecting suitable heterogenous gene that can efficiently enhance toxicity or broaden insecticidal spectrum of cry1ac through fusion expression, two hybrid cry1acs fused with chitinase-encoding gene tchib and neurotoxin gene hwtx-1 respectively were constructed and their toxicities were compared. a bacillus thuringiensis strain harboring the cry1ac gene in vector pht315 was used as control. bioassay revealed that lc(50) (after 72 h) of cry1ac protoxin was 41.01 μ ...201222806817
impact of transgenic cotton varieties on activity of enzymes in their rhizosphere.the impact of five bacillus thuringiensis (bt) cotton varieties and their respective isogenic non-bt(nbt) isolines (ankur-2534, mech-6304, rch-317, ankur-651 and mech-6301) was assessed on the key soil enzymes i.e., dehydrogenase, alkaline phosphatase and urease in their rhizosphere at four growth stages of the crop, namely vegetative, flowering, bolling and harvesting. these varieties were grown on farmer's field in villages 22 miles and 24 miles of ganganagar district of rajasthan state in ind ...201222803335
synthesis, antimicrobial evaluation and spectroscopic characterization of novel imidazolone, triazole and triazinone derivatives.the reactions of 2-phenyl-4-arylmethylene-2-oxazolin-5-ones (1a, b) and 2-phenyl-4-arylazo-2-oxazolin-5-ones (8a, b) with p-aminoazobenzene derivatives (2a-c) gave the corresponding imidazolone derivatives (4a-f) and triazole derivatives (10a-f), respectively. also, the reaction of 1a with o-aminophenol to give the imidazolone derivative 5 was studied. the reaction of 1a with 2,4-dinitrophenylhydrazine gave the corresponding 1,2,4-triazine derivatives 14a-c, respectively. the newly synthesized c ...201222796528
importance of rare taxa for bacterial diversity in the rhizosphere of bt- and conventional maize varieties.ribosomal 16s rrna gene pyrosequencing was used to explore whether the genetically modified (gm) bt-maize hybrid mon 89034 × mon 88017, expressing three insecticidal recombinant cry proteins of bacillus thuringiensis, would alter the rhizosphere bacterial community. fine roots of field cultivated bt-maize and three conventional maize varieties were analyzed together with coarse roots of the bt-maize. a total of 547,000 sequences were obtained. library coverage was 100% at the phylum and 99.8% at ...201222791236
effects of two varieties of bacillus thuringiensis maize on the biology of plodia interpunctella.on the market since 1996, genetically modified plants expressing an insecticidal toxin (cry toxin stemmed from bacillus thuringiensis) target several lepidopteran and coleopteran pests. in this study, we assessed the impact of two varieties of bt maize producing different toxins (cry1ab or cry1fa, respectively) on the biology of a storage pest: plodia interpunctella (hübner) (lepidoptera: pyralidae). the indianmeal moths were susceptible to both toxins but showed an escape behavior only from cry ...201222778907
lack of cry1fa binding to the midgut brush border membrane in a resistant colony of plutella xylostella moths with a mutation in the abcc2 locus.previous studies reported "mode 1" bacillus thuringiensis resistance in a colony of diamondback moths (no-qa), and recently, this resistance has been mapped to an abc transporter (abcc2) locus. we report the lack of binding of cry1fa to insects derived from this colony and compare our data with those from other insects with abcc2-associated resistance.201222773634
weak transcription of the cry1ac gene in nonsporulating bacillus thuringiensis cells.the cry1ac gene of bacillus thuringiensis subsp. kurstaki hd-73 (b. thuringiensis hd-73) is a typical example of a sporulation-dependent crystal gene and is controlled by sigma e and sigma k during sporulation. to monitor the production and accumulation of cry1ac at the cellular level, we developed a green fluorescent protein-based reporter system. the production of cry1ac was monitored in spo0a, sige, and sigk mutants, and these mutants were able to express the cry1ac-green fluorescent protein ...201222773626
alteration of leaf metabolism in bt-transgenic rice (oryza sativa l.) and its wild type under insecticide stress.insecticide is always used to control the damage from pests, while the potential influence on plants is rarely known. time-course metabolic changes of wild and bacillus thuringiensis (bt) transgenic rice (oryza sativa l.) plants after insecticide treatment were investigated by using gas chromatography-mass spectrometry (gc-ms). a combined statistical strategy of 2-way anova and multivariate analyses (principal component analysis and hierarchal cluster analysis) was performed to find the stress-a ...201222768924
the dynamics of cooperative bacterial virulence in the field.laboratory experiments have shown that the fitness of microorganisms can depend on cooperation between cells. although this insight has revolutionized our understanding of microbial life, results from artificial microcosms have not been validated in complex natural populations. we investigated the sociality of essential virulence factors (crystal toxins) in the pathogen bacillus thuringiensis using diamondback moth larvae (plutella xylostella) as hosts. we show that toxin production is cooperati ...201222767928
investigation of the cry4b-prohibitin interaction in aedes aegypti cells.bacillus thuringiensis (bt) produces insecticidal toxins active against insects. cry4b, one of the major insecticidal toxins produced by bt subsp. israelensis, is highly toxic to mosquitoes in the genus aedes: the major vectors of dengue, yellow fever, and chikungunya. previous work has shown that cry4b binds to several mid-gut membrane proteins in aedes aegypti larvae including prohibitin, a protein recently identified as a receptor that also mediates entry of dengue virus into aedes cells. thi ...201222767320
vip3a resistance alleles exist at high levels in australian targets before release of cotton expressing this toxin.crops engineered to produce insecticidal crystal (cry) proteins from the soil bacterium bacillus thuringiensis (bt) have revolutionised pest control in agriculture. however field-level resistance to bt has developed in some targets. utilising novel vegetative insecticidal proteins (vips), also derived from bt but genetically distinct from cry toxins, is a possible solution that biotechnical companies intend to employ. using data collected over two seasons we determined that, before deployment of ...201222761737
economic impacts and impact dynamics of bt (bacillus thuringiensis) cotton in india.despite widespread adoption of genetically modified crops in many countries, heated controversies about their advantages and disadvantages continue. especially for developing countries, there are concerns that genetically modified crops fail to benefit smallholder farmers and contribute to social and economic hardship. many economic studies contradict this view, but most of them look at short-term impacts only, so that uncertainty about longer-term effects prevails. we address this shortcoming b ...201222753493
an amoeba phagocytosis model reveals a novel developmental switch in the insect pathogen bacillus thuringiensis.the bacillus cereus group bacteria contain pathogens of economic and medical importance. from security and health perspectives, the lethal mammalian pathogen bacillus anthracis remains a serious threat. in addition the potent insect pathogen bacillus thuringiensis is extensively used as a biological control agent for insect pests. this relies upon the industrial scale induction of bacterial spore formation with the associated production of orally toxic cry-toxins. understanding the ecology and p ...201322750551
a tenebrio molitor gpi-anchored alkaline phosphatase is involved in binding of bacillus thuringiensis cry3aa to brush border membrane vesicles.bacillus thuringiensis cry toxins recognizes their target cells in part by the binding to glycosyl-phosphatidyl-inositol (gpi) anchored proteins such as aminopeptidase-n (apn) or alkaline phosphatases (alp). treatment of tenebrio molitor brush border membrane vesicles (bbmv) with phospholipase c that cleaves out gpi-anchored proteins from the membranes, showed that gpi-anchored proteins are involved in binding of cry3aa toxin to bbmv. a 68 kda gpi-anchored alp was shown to bind cry3aa by toxin o ...201322743140
in vitro uptake of 140 kda bacillus thuringiensis nematicidal crystal proteins by the second stage juvenile of meloidogyne hapla.plant-parasitic nematodes (ppns) are piercing/sucking pests, which cause severe damage to crops worldwide, and are difficult to control. the cyst and root-knot nematodes (rkn) are sedentary endoparasites that develop specialized multinucleate feeding structures from the plant cells called syncytia or giant cells respectively. within these structures the nematodes produce feeding tubes, which act as molecular sieves with exclusion limits. for example, heterodera schachtii is reportedly unable to ...201222737212
two new brazilian isolates of bacillus thuringiensis toxic to anticarsia gemmatalis (lepidoptera: noctuidae).bacillus thuringiensis is a bacterium used for biopesticides production and pest-resistant plants due to the synthesis of protein crystals by cry genes, which are effective in controlling several insect orders such as lepidoptera. this work aimed at the evaluation and characterisation of two new b. thuringiensis isolates active against a. gemmatalis (hübner 1818) larvae, which is the soybean major pest. the results showed that bt117-4 isolate amplified fragments corresponding to cry2 and cry9 ge ...201222735145
isolation of bacillus thuringiensis strains that contain dipteran-specific cry genes from ilha bela (são paulo, brazil) soil samples.the entomophatogenic bacterium bacillus thuringiensis produces crystal proteins, named cry proteins which are encoded by the cry genes. this bacterium is used on biological control of important economical pests, as well as in the control of disease´s vectors, such as aedes aegypti, a mosquito that transmits the dengue viruses. isolates of this bacterium can be characterized by the content of cry genes and this prediction helps target different insect orders. in this research, we isolated 76 colo ...201222735130
aedes aegypti alkaline phosphatase alp1 is a functional receptor of bacillus thuringiensis cry4ba and cry11aa toxins.bacillus thuringiensis subs. israelensis produces at least three cry toxins (cry4aa, cry4ba, and cry11aa) that are active against aedes aegypti larvae. previous work characterized a gpi-anchored alkaline phosphatase (alp1) as a cry11aa binding molecule from the gut of a. aegypti larvae. we show here that cry4ba binds alp1, and that the binding and toxicity of cry4ba mutants located in loop 2 of domain ii is correlated. also, we analyzed the contribution of alp1 toward the toxicity of cry4ba and ...201222728570
two new coumarins from micromelum falcatum with cytotoxicity and brine shrimp larvae toxicity.two new coumarins, 7-methoxy-8-(2-hydroxmethyl-1-o-isovaleryl-4-butenyl)-coumarin (1) and 7-methoxy-8-(1-hydroxy-2-o-β-glucopyranosyl-3-methyl-4-butene-1-yl)coumarin (2), and twelve known coumarins 3-14 were isolated from the stem bark of micromelum falcatum. the structures of compounds 1-14 were elucidated by extensive spectroscopic data analyses. the toxicity of compounds 1-14 was tested using a brine shrimp assay and in vitro antiproliferative assay against mammary cancer (f10) and lung cance ...201222728368
bacillus spp. toxicity against haemonchus contortus larvae in sheep fecal cultures.the gastrointestinal nematode haemonchus contortus is a major productivity constraint in sheep. in this study, the nematicidal effects of bacillus circulans, bacillus cereus, bacillus thuringiensis var. israelensis, bt. var. osvaldocruzi, bt. var. morrisoni, and bt. var. kurstaki were assessed in free-living larval stages of h. contortus. a spore-crystal suspension containing approximately 2×10(8)ufc/ml of each strain was added to sheep feces that were naturally infected with h. contortus eggs, ...201222728159
widespread adoption of bt cotton and insecticide decrease promotes biocontrol services.over the past 16 years, vast plantings of transgenic crops producing insecticidal proteins from the bacterium bacillus thuringiensis (bt) have helped to control several major insect pests and reduce the need for insecticide sprays. because broad-spectrum insecticides kill arthropod natural enemies that provide biological control of pests, the decrease in use of insecticide sprays associated with bt crops could enhance biocontrol services. however, this hypothesis has not been tested in terms of ...201222722864
determination of cry toxin activity and identification of an aminopeptidase n receptor-like gene in asymmathetes vulcanorum (coleoptera: curculionidae).an emergent pest is the weevil asymmathetes vulcanorum, an insect that attacks colombian potato areas. here, some cry proteins from the entomopathogenic bacteria bacillus thuringiensis were evaluated as biological control strategy. it was found that cry1b protoxin caused a mortality of 40% with a dose of 8000 ng/cm(2). also in this research, it was identified a full length cdna of an aminopeptidase n, a possible cry protein receptor located in the insect midgut. this is the first report about b. ...201222721915
fusing the vegetative insecticidal protein vip3aa7 and the n terminus of cry9ca improves toxicity against plutella xylostella larvae.bacillus thuringiensis insecticidal crystal proteins (icps) and vegetative insecticidal proteins (vips) have been widely used as a kind of safe bio-insecticides. a problem that has been of concern worldwide is how to improve their insecticidal activities. in this study, to determine the synergism between vips and icps effect on insecticidal activity, a construct that produces a chimeric protein of the vip3aa7 and the n terminus ofcry9ca, named v3ac9c, was expressed in escherichia coli bl21 cells ...201222718249
phenotypic and genotypic characterization of b.t.ldc-391 strain that produce cytocidal proteins against human cancer cells.an indigenous bacillus thuringiensis strain b.t.ldc-391 producing cytocidal proteins against human colon cancer cell line, hct-116, was subjected to phenotypic and genotypic characterization to evaluate its relatedness to b.anthracis. the morphological features of this strain were meta-analyzed with data of other parasporin and insecticidal protein producing bacillus thuringiensis strains. the conventional biochemical analysis and antibiotic sensitivity test proved it as an ampicillin resistant ...201222715300
a 90-day subchronic feeding study of genetically modified maize expressing cry1ac-m protein in sprague-dawley rats.the cry1ac-m gene, coding one of bacillus thuringiensis (bt) crystal proteins, was introduced into maize h99 × hi iib genome to produce insect-resistant gm maize bt-38. the food safety assessment of the bt-38 maize was conducted in sprague-dawley rats by a 90-days feeding study. we incorporated maize grains from bt-38 and h99 × hi iib into rodent diets at three concentrations (12.5%, 25%, 50%) and administered to sprague-dawley rats (n=10/sex/group) for 90 days. a commercialized rodent diet was ...201222709787
proteomic analysis of bacillus thuringiensis δphac mutant bmb171/phb(-1) reveals that the phb synthetic pathway warrants normal carbon metabolism.a phac knockout mutant from bacillus thuringiensis (bt) strain bmb171, named bmb171/phb(-1), was constructed. a physiological and metabolic investigation and a proteomic analysis were conducted for both δphac mutant and its parent strain. grown in peptone medium with 5 gram glucose per liter as sole carbon source, bmb171/phb(-1) produced various organic acids. here the excreted pyruvate, citrate, lactate, acetate and glutamate were quantitatively analyzed. deletion of phac gene from the bmb171 s ...201222705120
larval midgut modifications associated with bti resistance in the yellow fever mosquito using proteomic and transcriptomic approaches.bacillus thuringiensis var. israelensis (bti) is a natural larval mosquito pathogen producing pore-forming toxins targeting the midgut of diptera larvae. it is used worldwide for mosquito control. resistance mechanisms of an aedes aegypti laboratory strain selected for 30 generations with field-collected leaf litter containing bti toxins were investigated in larval midguts at two levels: 1. gene transcription using dna microarray and rt-qpcr and 2. differential expression of brush border membran ...201222703117
immunosuppressive properties of a protein (rvpr1) from the venom of the endoparasitic wasp, pimpla hypochondriaca: mechanism of action and potential use for improving biological control strategies.previously, it was determined that the presence of rvpr1 (a recombinant pimpla hypochondriaca venom protein), in the haemocoel of two lepidopteran larvae, significantly increases their susceptibility to the biological control agents (bcas), bacillus thuringiensis (bt) and beauveria bassiana (richards and dani, 2010; richards et al., 2011). the current work examines the mechanism of action of rvpr1 and demonstrates that it binds to the surface of some haemocytes and disrupts the organization of t ...201322698823
cyt toxins produced by bacillus thuringiensis: a protein fold conserved in several pathogenic microorganisms.bacillus thuringiensis bacteria produce different insecticidal proteins known as cry and cyt toxins. among them the cyt toxins represent a special and interesting group of proteins. cyt toxins are able to affect insect midgut cells but also are able to increase the insecticidal damage of certain cry toxins. furthermore, the cyt toxins are able to overcome resistance to cry toxins in mosquitoes. there is an increasing potential for the use of cyt toxins in insect control. however, we still need t ...201322691603
diverse genetic basis of field-evolved resistance to bt cotton in cotton bollworm from china.evolution of pest resistance reduces the efficacy of insecticidal proteins from bacillus thuringiensis (bt) used in sprays or in transgenic crops. although several pests have evolved resistance to bt crops in the field, information about the genetic basis of field-evolved resistance to bt crops has been limited. in particular, laboratory-selected resistance to bt toxin cry1ac based on recessive mutations in a gene encoding a toxin-binding cadherin protein has been identified in three major cotto ...201222689968
understanding successful resistance management: the european corn borer and bt corn in the united states.the european corn borer, ostrinia nubilalis hübner (lepidoptera: crambidae) has been a major pest of corn and other crops in north america since its accidental introduction nearly a hundred years ago. wide adoption of transgenic corn hybrids that express toxins from bacillus thuringiensis, referred to as bt corn, has suppressed corn borer populations and reduced the pest status of this insect in parts of the corn belt. continued suppression of this pest, however, will depend on managing potentia ...201422688691
the design and implementation of insect resistance management programs for bt crops.cotton and corn plants with insect resistance traits introduced through biotechnological methods and derived from the bacterium bacillus thuringiensis (bt) have been widely adopted since they were first introduced in 1996. because of concerns about resistance evolving to these bt crops, they have been released with associated irm programs that employ multiple components and reflect the input of academic, industrial and regulatory experts. this paper summarizes the current status of bt crop techn ...201422688689
western corn rootworm and bt maize: challenges of pest resistance in the field.crops genetically engineered to produce insecticidal toxins from the bacterium bacillus thuringiensis (bt) manage many key insect pests while reducing the use of conventional insecticides. one of the primary pests targeted by bt maize in the united states is the western corn rootworm, diabrotica virgifera virgifera leconte. beginning in 2009, populations of western corn rootworm were identified in iowa, usa that imposed severe root injury to cry3bb1 maize. subsequent laboratory bioassays reveale ...201422688688
extended monitoring of resistance to bacillus thuringiensis cry1ab maize in diatraea saccharalis (lepidoptera: crambidae).the sugarcane borer, diatraea saccharalis (f.), is a major target of transgenic maize expressing bacillus thuringiensis (bt) proteins in south america and the mid-southern region of the united states. during 2007-2009, a total of 986 feral individuals of d. saccharalis were collected from maize fields in six locations of louisiana and mississippi and examined for resistance to cry1ab maize using f 1/f 2 screens. major resistance alleles to cry1ab maize in the populations sampled from non-bt maiz ...201422688686
molecular typing of native bacillus thuringiensis isolates from diverse habitats in india using rep-pcr and eric-pcr analysis.bacillus thuringiensis is a bacterium of great agronomic and scientific interest. the subspecies of this bacterium colonize and kill a large variety of host insects and even nematodes, but each strain does so with a high degree of specificity. therefore molecular typing and diversity analysis of b. thuringiensis has enormous importance for discrimination of strains isolated from different sources. in this study, 113 native b. thuringiensis isolates collected from diverse habitats and locations i ...201222688239
association of cry1ac toxin resistance in helicoverpa zea (boddie) with increased alkaline phosphatase levels in the midgut lumen.resistance to bacillus thuringiensis cry1ac toxin was characterized in a population of helicoverpa zea larvae previously shown not to have an alteration in toxin binding as the primary resistance mechanism to this toxin. cry1ac-selected larvae (ar1) were resistant to protoxins and toxins of cry1ab, cry1ac, and the corresponding modified proteins lacking helix α-1 (cry1abmod and cry1acmod). when comparing brush border membrane vesicles (bbmvs) prepared from susceptible (lc) and ar1 larval midguts ...201222685140
structure, biosynthesis, and properties of kurstakins, nonribosomal lipopeptides from bacillus spp.a new family of lipopeptides produced by bacillus thuringiensis, the kurstakins, was discovered in 2000 and considered as a biomarker of this species. kurstakins are lipoheptapeptides displaying antifungal activities against stachybotrys charatum. recently, the biosynthesis mechanism, the regulation of this biosynthesis and the potential new properties of kurstakins were described in the literature. in addition, kurstakins were also detected in other species belonging to bacillus genus such as b ...201222678024
transport of bacillus thuringiensis var. kurstaki from an outdoor release into buildings: pathways of infiltration and a rapid method to identify contaminated buildings.understanding the fate and transport of biological agents into buildings will be critical to recovery and restoration efforts after a biological attack in an urban area. as part of the interagency biological restoration demonstration (ibrd), experiments were conducted in fairfax county, va, to study whether a biological agent can be expected to infiltrate into buildings following a wide-area release. bacillus thuringiensis var. kurstaki is a common organic pesticide that has been sprayed in fair ...201222676846
efficacy of sunlight-activatable porphyrin formulates on larvae of anopheles gambiae m and s molecular forms and an. arabiensis: a potential novel biolarvicide for integrated malaria vector control.biolarvicides, such as microbial formulations based on bacillus thuringiensis and b. sphaericus, have been found to be highly effective against mosquito larvae and are currently employed as eco-friendly alternatives to synthetic chemical insecticides for vector control. recently, a porphyrin of natural origin has been suggested as a sunlight-activatable larvicide against the dengue vector aedes aegypti. in order to validate the approach for the control of the malaria vector, we tested the photo- ...201222668835
islands of non-essential genes, including a dna translocation operon, in the genome of bacteriophage 0305ϕ8-36.we investigate genes of lytic, bacillus thuringiensis bacteriophage 0305ϕ8-36 that are non-essential for laboratory propagation, but might have a function in the wild. we isolate deletion mutants to identify these genes. the non-permutation of the genome (218.948 kb, with a 6.479 kb terminal repeat and 247 identified orfs) simplifies isolation of deletion mutants. we find two islands of non-essential genes. the first island (3.01% of the genomic dna) has an informatically identified dna transloc ...201222666654
exploring the midgut transcriptome and brush border membrane vesicle proteome of the rice stem borer, chilo suppressalis (walker).the rice stem borer, chilo suppressalis (walker) (lepidoptera: pyralidae), is one of the most detrimental pests affecting rice crops. the use of bacillus thuringiensis (bt) toxins has been explored as a means to control this pest, but the potential for c. suppressalis to develop resistance to bt toxins makes this approach problematic. few c. suppressalis gene sequences are known, which makes in-depth study of gene function difficult. herein, we sequenced the midgut transcriptome of the rice stem ...201222666467
insecticidal activity of bacillus thuringiensis strains isolated from soil and water.we attempted to search novel bacillus thuringiensis strains that produce crystals with potential utility in plant protection and with higher activity than strains already used in biopesticide production. seven b. thuringiensis soil and water isolates were used in the research. we predicted the toxicity of their crystals by cry gene identification employing pcr method. the isolate mpu b63 with interesting, according to us, genes content was used in evaluating its crystal toxicity against cydia po ...201222666145
effectiveness of gambusia holbrooki fish in domestic water containers and controlling aedes aegypti larvae (linnaeus, 1762) in southwest saudi arabia (jeddah).the objective of this study was to estimate the survival of gambusia holbrooki (cyprinodontiformes: poeciliidae) fishin domestic containers in jeddah, as well as its effectiveness in the control of immature a.aegypti. the use of g. holbrooki compared to bacillus thuringiensis israelensis (b.t.i.)was donein domestic containers. in a first home visit, g. holbrooki or b.t.i were applied to water containers. two follow-up visits were conducted after 3-4 & 5-6 months to assess the presence of viable ...201222662590
genome characteristics of a novel phage from bacillus thuringiensis showing high similarity with phage from bacillus cereus.bacillus thuringiensis is an important entomopathogenic bacterium belongs to the bacillus cereus group, which also includes b. anthracis and b. cereus. several genomes of phages originating from this group had been sequenced, but no genome of siphoviridae phage from b. thuringiensis has been reported. we recently sequenced and analyzed the genome of a novel phage, btcs33, from a b. thuringiensis strain, subsp. kurstaki cs33, and compared the gneome of this phage to other phages of the b. cereus ...201222649540
proteomic analysis of bacillus thuringiensis strain 4.0718 at different growth phases.the growth process of bacillus thuringiensis bt4.0718 strain was studied using proteomic technologies. the proteins of bt whole cells at three phases-middle vegetative, early sporulation, and late sporulation-were extracted with lysis buffer, followed with separation by 2-de and identified by maldi-tof/tof ms. bioactive factors such as insecticidal crystal proteins (icps) including cry1ac(3), cry2aa, and btrx28, immune inhibitor (inha), and inha precursor were identified. inha started to express ...201222649324
production of the antimicrobial peptides caseicin a and b by bacillus isolates growing on sodium caseinate.the aim of this study was to identify bacillus isolates capable of degrading sodium caseinate and subsequently to generate bioactive peptides with antimicrobial activity.201222642665
bacillus thuringiensis cry3aa protoxin intoxication of tenebrio molitor induces widespread changes in the expression of serine peptidase transcripts.the yellow mealworm, tenebrio molitor, is a pest of stored grain products and is sensitive to the bacillus thuringiensis (bt) cry3aa toxin. as digestive peptidases are a determining factor in cry toxicity and resistance, we evaluated the expression of peptidase transcripts in the midgut of t. molitor larvae fed either a control or cry3aa protoxin diet for 24 h (rna-seq), or in larvae exposed to the protoxin for 6, 12, or 24 h (microarrays). cysteine peptidase transcripts (9) were similar to cath ...201222640634
proteomic analysis of bacillus thuringiensis at different growth phases by using an automated online two-dimensional liquid chromatography-tandem mass spectrometry strategy.the proteome of a new bacillus thuringiensis subsp. kurstaki strain, 4.0718, from the middle vegetative (t(1)), early sporulation (t(2)), and late sporulation (t(3)) phases was analyzed using an integrated liquid chromatography (lc)-based protein identification system. the system comprised two-dimensional (2d) lc coupled with nanoscale electrospray ionization (esi) tandem mass spectrometry (ms/ms) on a high-resolution hybrid mass spectrometer with an automated data analysis system. after deletio ...201222636013
single amino acid mutation in an atp-binding cassette transporter gene causes resistance to bt toxin cry1ab in the silkworm, bombyx mori.bt toxins derived from the arthropod bacterial pathogen bacillus thuringiensis are widely used for insect control as insecticides or in transgenic crops. bt resistance has been found in field populations of several lepidopteran pests and in laboratory strains selected with bt toxin. widespread planting of crops expressing bt toxins has raised concerns about the potential increase of resistance mutations in targeted insects. by using bombyx mori as a model, we identified a candidate gene for a re ...201222635270
how the insect pathogen bacteria bacillus thuringiensis and xenorhabdus/photorhabdus occupy their hosts.insects are the largest group of animals on earth. like mammals, virus, fungi, bacteria and parasites infect them. several tissue barriers and defense mechanisms are common for vertebrates and invertebrates. therefore some insects, notably the fly drosophila and the caterpillar galleria mellonella, have been used as models to study host-pathogen interactions for several insect and mammal pathogens. they are excellent tools to identify pathogen determinants and host tissue cell responses. we focu ...201222633889
rapid isolation of single-chain antibodies from a human synthetic phage display library for detection of bacillus thuringiensis (bt) cry1b toxin.single chain variable fragment antibody (scfv) is capable of binding its target antigens and is one of the most popular recombinant antibodies format for many applications. in this study, a large human synthetic phage displayed library (tomlinson j) was employed to generate scfvs against cry1b toxin by affinity panning. after four rounds of panning, six monoclonal phage particles capable of binding with the cry1b were isolated, sequenced and characterized by enzyme-linked immunosorbent assay (el ...201222627013
current models of the mode of action of bacillus thuringiensis insecticidal crystal proteins: a critical review.bacillus thuringiensis (bt) cry toxins constitute the active ingredient in the most widely used biological insecticides and insect-resistant transgenic crops. a clear understanding of their mode of action is necessary for improving these products and ensuring their continued use. accordingly, a long history of intensive research has established that their toxic effect is due primarily to their ability to form pores in the plasma membrane of the midgut epithelial cells of susceptible insects. in ...201222617276
comparative proteomic analysis of aedes aegypti larval midgut after intoxication with cry11aa toxin from bacillus thuringiensis.cry toxins produced by bacillus thuringiensis bacteria are environmentally safe alternatives to control insect pests. they are pore-forming toxins that specifically affect cell permeability and cellular integrity of insect-midgut cells. in this work we analyzed the defensive response of aedes aegypti larva to cry11aa toxin intoxication by proteomic and functional genomic analyses. two dimensional differential in-gel electrophoresis (2d-dige) was utilized to analyze proteomic differences among a. ...201222615881
decreased toxicity of bacillus thuringiensis subsp. israelensis to mosquito larvae after contact with leaf litter.bacillus thuringiensis subsp. israelensis is a bacterium producing crystals containing cry and cyt proteins, which are toxic for mosquito larvae. nothing is known about the interaction between crystal toxins and decaying leaf litter, which is a major component of several mosquito breeding sites and represents an important food source. in the present work, we investigated the behavior of b. thuringiensis subsp. israelensis toxic crystals sprayed on leaf litter. in the presence of leaf litter, a 6 ...201222610426
spinosad: a biorational mosquito larvicide for use in car tires in southern mexico.car tires are important habitats for mosquito development because of the high density populations they can harbor and their presence in urban settings. water in experimental tires was treated with one of three insecticides or an untreated control. aquatic invertebrates were sampled at weekly intervals. eggs, larval and pupal samples were laboratory-reared to estimate seasonal fluctuations in aedes aegypti and ae. albopictus abundance.201222608138
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