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the transcriptome of spodoptera exigua larvae exposed to different types of microbes.we have obtained and characterized the transcriptome of spodoptera exigua larvae with special emphasis on pathogen-induced genes. in order to obtain a highly representative transcriptome, we have pooled rna from diverse insect colonies, conditions and tissues. sequenced cdna included samples from 3 geographically different colonies. enrichment of rna from pathogen-related genes was accomplished by exposing larvae to different pathogenic and non-pathogenic microbial agents such as the bacteria ba ...201222564783
transcriptome profiling of the intoxication response of tenebrio molitor larvae to bacillus thuringiensis cry3aa protoxin.bacillus thuringiensis (bt) crystal (cry) proteins are effective against a select number of insect pests, but improvements are needed to increase efficacy and decrease time to mortality for coleopteran pests. to gain insight into the bt intoxication process in coleoptera, we performed rna-seq on cdna generated from the guts of tenebrio molitor larvae that consumed either a control diet or a diet containing cry3aa protoxin. approximately 134,090 and 124,287 sequence reads from the control and cry ...201222558093
expression and characterization of a recombinant cry1ac crystal protein fused with an insect-specific neurotoxin ω-actx-hv1a in bacillus thuringiensis.in order to assess possible enhancement of biopesticide activity, the fusion gene of crystal protein gene cry1ac with the insect-specific neurotoxin ω-actx-hv1a gene and egfp was expressed in bacillus thuringiensis acrystalliferous strain cry-b under the control of the native gene expression system. the fusion recombinant cry-b(1ac-actx-egfp) generally produced two or three small crystal-like inclusion bodies in each cell and the gfp signal could be clearly observed. a 166 kda full-length fusion ...201222548233
mining new crystal protein genes from bacillus thuringiensis on the basis of mixed plasmid-enriched genome sequencing and a computational pipeline.we have designed a high-throughput system for the identification of novel crystal protein genes (cry) from bacillus thuringiensis strains. the system was developed with two goals: (i) to acquire the mixed plasmid-enriched genomic sequence of b. thuringiensis using next-generation sequencing biotechnology, and (ii) to identify cry genes with a computational pipeline (using bttoxin_scanner). in our pipeline method, we employed three different kinds of well-developed prediction methods, blast, hidd ...201222544259
a 50-kilodalton cry2a peptide is lethal to bombyx mori and lymantria dispar.the cry2aa3 gene was introduced into asporogenic bacillus thuringiensis, and the synthesized protoxin killed bombyx mori and lymantria dispar larvae. chymotrypsin hydrolyzed the linkages between 49tyr/val50 and 145lys/ser146 in the protoxin, and 50- and 58-kda fragments were generated, respectively. both peptides killed the larvae of both insects.201222544240
a novel cost-effective medium for the production of bacillus thuringiensis subsp. israelensis for mosquito control.bacillus thuringiensis subsp. israelensis (bti) has been used for mosquito-control programmes the world-wide. indeed, the large-scale production of bti for mosquito control is very expensive due to the high cost of its culture. in the present study, we attempted to widen the scope in developing cost-effective culture medium for bti production, based on the raw materials available on the biosphere, including coconut cake powder, ccp (cocos nucifera), neem cake powder, ncp (azadirachta indica) and ...201222543607
quantification of cry1ab in genetically modified maize leaves by liquid chromatography multiple reaction monitoring tandem mass spectrometry using 18o stable isotope dilution.cry1ab is one of the most common bacillus thuringiensis (bt) proteins in genetically modified crops, which exhibits strong resistance against insect pests. in the present study, a sensitive and precise liquid chromatography stable isotope dilution multiple reaction monitoring tandem mass spectrometry (lc-sid-mrm-ms) assay was developed and validated to quantify the amount of cry1ab expression in transgenic maize leaves. the measurement of protein was converted to measurement of unique peptides t ...201222543512
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
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
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
preparation of silver nanoparticles in the presence of chitosan by electrochemical method.the present study involves the development of stabilized and densely dispersed chitosan-silver nanoparticles using a green approach based on electrochemical oxidation/complexation process followed by uv irradiation reduction. formation of the nanoparticles was confirmed by appearance of surface plasmon absorption around 420 nm. the nanoparticles were characterized using transmission electron microscopy, x-ray diffraction, elemental analysis, atomic absorption, energy dispersive x-ray, fourier tr ...201224750629
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
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
effects of temperature on mortality of larval stable fly (diptera: muscidae) caused by five isolates of bacillus thuringiensis.we examined the effects of temperature on mortality of larval stable fly [stomoxys calcitrans (l.)] caused by bacillus thuringiensis tolworthi 4l3, b. t. darmastedensis 4m1, b. t. thompsoni 401, b. t. thuringiensis hd2, and b. t. kurstaki hd945. at moderate doses, mortality caused by all isolates ranged from 87 to 99% at 15 degrees c and declined to 29-63% as temperature increased to 30 degrees c. a similar pattern was seen when a higher dose was used, except that the reduction in mortality at w ...201222606847
cotton plants expressing a hemipteran-active bacillus thuringiensis crystal protein impact the development and survival of lygus hesperus (hemiptera: miridae) nymphs.the plant bugs lygus hesperus knight (hemiptera: miridae) and l. lineolaris (palisot de beauvois) have emerged as economic pests of cotton in the united states. these hemipteran species are refractory to the insect control traits found in genetically modified commercial varieties of cotton. in this article, we report the isolation and characterization of a 35 kda crystal protein from bacillus thuringiensis, designated tic807, which causes reduced mass gain and mortality of l. hesperus and l. lin ...201222606834
resistance of trichoplusia ni to bacillus thuringiensis toxin cry1ac is independent of alteration of the cadherin-like receptor for cry toxins.alteration of binding sites for bacillus thuringiensis (bt) toxins in insect midgut is the major mechanism of high-level resistance to bt toxins in insects. the midgut cadherin is known to be a major binding protein for bt cry1a toxins and linkage of bt-resistance to cadherin gene mutations has been identified in lepidopterans. the resistance to bt toxin cry1ac evolved in greenhouse populations of trichoplusia ni has been identified to be associated with the down-regulation of an aminopeptidase ...201222606242
bacillus thuringiensis parasporal proteins induce cell-cycle arrest and caspase-dependant apoptotic cell death in leukemic cells.bacillus thuringiensis (bt) parasporal proteins with selective anticancer activity have recently garnered interest. this study determines the efficacy and mode of cell death of bt 18 parasporal proteins against 3 leukemic cell lines (cem-ss, ccrf-sb and ccrf-hsb-2).cell-based biochemical analysis aimed to determine cell viability and the percentage of apoptotic cell death in treated cell lines; ultrastructural analysis to study apoptotic changes and western blot to identify the parasporal protei ...201222591286
computational tridimensional protein modeling of cry1ab19 toxin from bacillus thuringiensis btx-2.we report the computational structural simulation of the cry1ab19 toxin molecule from b. thuringiensis btx-2 based on the structure of cry1aa1 deduced by x-ray diffraction. validation results showed that 93.5% of modeled residues are folded in a favorable orientation with a total energy z-score of -8.32, and the constructed model has an rmsd of only 1.13. the major differences in the presented model are longer loop lengths and shortened sheet components. the overall result supports the hierarchi ...201222573155
rflp analysis of cry1 and cry2 genes of bacillus thuringiensis isolates from india.the pcr-rflp method has been useful for detection of known genes and identification of novel genes. in the present study, degenerate primers were designed from five groups of cry1 genes for pcr-rflp analysis. bacillus thuringiensis (bt) isolates from different regions were evaluated for pcr amplification of various cry1 genes using newly designed primers and cry2 genes using reported primers. pcr analysis showed an abundance of cry1a genes and especially cry1ac genes in isolates from all regions ...201222573148
biofunctionalization of nanoparticle assisted mass spectrometry as biosensors for rapid detection of plant associated bacteria.this study is based on the application of matrix-assisted laser desorption/ionization time of flight mass spectrometry (maldi-tof ms) as biosensor to detect the plant associated bacteria (pab) isolates from rhizospheric soil and root. the rapid bacterial detection via on particle ionization/enrichment technique using igg functionalized pt nps (igg-pt nps) assisted maldi-tof ms was successfully used to explore two pab isolates, namely, bacillus thuringiensis and b. subtilis from rhizospheric soil ...201222436686
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
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
field-evolved resistance to bt maize by western corn rootworm: predictions from the laboratory and effects in the field.crops engineered to produce insecticidal toxins derived from the bacterium bacillus thuringiensis (bt) provide an effective management tool for many key insect pests. however, pest species have repeatedly demonstrated their ability to adapt to management practices. results from laboratory selection experiments illustrate the capacity of pest species to evolve bt resistance. furthermore, resistance has been documented to bt sprays in the field and greenhouse, and more recently, by some pests to b ...201222537837
early detection of field-evolved resistance to bt cotton in china: cotton bollworm and pink bollworm.transgenic crops producing bacillus thuringiensis (bt) toxins kill some major insect pests, but pests can evolve resistance and thereby reduce the effectiveness of such bt crops. the main approach for slowing pest adaptation to bt crops uses non-bt host plants as "refuges" to increase survival of susceptible pests. to delay evolution of pest resistance to cotton producing bt toxin cry1ac, several countries have required refuges of non-bt cotton, while farmers in china have relied on "natural" re ...201222537835
the saposin-like protein spp-12 is an antimicrobial polypeptide in the pharyngeal neurons of caenorhabditis elegans and participates in defence against a natural bacterial pathogen.caenopores are antimicrobial and pore-forming polypeptides in caenorhabditis elegans belonging to the saposin-like protein superfamily and are considered important elements of the nematode's intestinal immune system. in the present study, we demonstrate that, unlike the other members of the multifarious gene family (spps) coding for caenopores, spp-12 is expressed exclusively in two pharyngeal neurons. recombinantly expressed spp-12 binds to phospholipid membranes and forms pores in a ph-depende ...201222519640
transgenic cry1ab rice does not impact ecological fitness and predation of a generalist spider.the commercial release of rice genetically engineered to express a cry1ab protein from bacillus thuringiensis (bt) for control of lepidoptera in china is a subject of debate. one major point of the debate has focused on the ecological safety of bt rice on nontarget organisms, especially predators and parasitoids that help control populations of insect pests.201222511982
necrotrophism is a quorum-sensing-regulated lifestyle in bacillus thuringiensis.how pathogenic bacteria infect and kill their host is currently widely investigated. in comparison, the fate of pathogens after the death of their host receives less attention. we studied bacillus thuringiensis (bt) infection of an insect host, and show that nprr, a quorum sensor, is active after death of the insect and allows bt to survive in the cadavers as vegetative cells. transcriptomic analysis revealed that nprr regulates at least 41 genes, including many encoding degradative enzymes or p ...201222511867
identification of the promoter in the intergenic region between orf1 and cry8ea1 controlled by sigma h factor.bacillus thuringiensis cry8ea toxin is specifically toxic to larvae of the asian cockchafer, holotrichia parallela. here we investigated the mechanism of transcriptional regulation of the cry8ea1 gene. reverse transcription-pcr (rt-pcr) results indicated that cry8ea1 and an upstream gene (orf1) were cotranscribed. transcriptional fusions with the lacz gene demonstrated that transcription of the cry8ea1 gene started from two promoters: p(orf1), which is located upstream of the orf1 gene, and p(cr ...201222504821
evidence of reduced arbuscular mycorrhizal fungal colonization in multiple lines of bt maize.insect-resistant bacillus thuringiensis (bt) maize is widely cultivated, yet few studies have examined the interaction of symbiotic arbuscular mycorrhizal fungi (amf) with different lines of bt maize. as obligate symbionts, amf may be sensitive to genetic changes within a plant host. previous evaluations of the impact of bt crops on amf have been inconsistent, and because most studies were conducted under disparate experimental conditions, the results are difficult to compare.201222473978
high-throughput sequence-based analysis of the intestinal microbiota of weanling pigs fed genetically modified mon810 maize expressing bacillus thuringiensis cry1ab (bt maize) for 31 days.the objective of this study was to investigate if feeding genetically modified (gm) mon810 maize expressing the bacillus thuringiensis insecticidal protein (bt maize) had any effects on the porcine intestinal microbiota. eighteen pigs were weaned at ~28 days and, following a 6-day acclimatization period, were assigned to diets containing either gm (bt mon810) maize or non-gm isogenic parent line maize for 31 days (n = 9/treatment). effects on the porcine intestinal microbiota were assessed throu ...201222467509
susceptibility of spodoptera frugiperda and s. exigua to bacillus thuringiensis vip3aa insecticidal protein.the vip3aa protein is an insecticidal protein secreted by bacillus thuringiensis during the vegetative stage of growth. the activity of this protein has been tested after different steps/protocols of purification using spodoptera frugiperda as a control insect. the results showed that the vip3aa protoxin was stable and retained full toxicity after being subjected to common biochemical steps used in protein purification. bioassays with the protoxin in s. frugiperda and s. exigua showed pronounced ...201222465567
bacillus thuringiensis monogenic strains: screening and interactions with insecticides used against rice pests.the screening of bacillus thuringiensis (bt) cry proteins with high potential to control insect pests has been the goal of numerous research groups. in this study, we evaluated six monogenic bt strains (bt dendrolimus hd-37, bt kurstaki hd-1, bt kurstaki hd-73, bt thuringiensis 4412, bt kurstaki nrd-12 and bt entomocidus 60.5, which codify the cry1aa, cry1ab, cry1ac, cry1ba, cry1c, cry2a genes respectively) as potential insecticides for the most important insect pests of irrigated rice: spodopte ...201224031872
induction of defense response against rhizoctonia solani in cucumber plants by endophytic bacterium bacillus thuringiensis gs1.an endophytic bacterium, bacillus thuringiensis gs1, was isolated from bracken (pteridium aquilinum) and found to have maximal production of chitinase (4.3 units/ml) at 5 days after culture. this study investigated the ability of b. thuringiensis gs1 to induce resistance to rhizoctonia solani kacc 40111 (rs) in cucumber plants. chitinase activity was greatest in rs-treated plants at 4 days. beta-1,3- glucanase activity was highest in gs1-treated plants at 5 days. guaiacol peroxidase (gpod) activ ...201222450798
specific binding of radiolabeled cry1fa insecticidal protein from bacillus thuringiensis to midgut sites in lepidopteran species.cry1fa insecticidal protein was successfully radiolabeled with (125)i-na. specific binding to brush border membrane vesicles was shown for the lepidopteran species ostrinia nubilalis, spodoptera frugiperda, spodoptera exigua, helicoverpa armigera, heliothis virescens, and plutella xylostella. homologous competition assays were performed to obtain equilibrium binding parameters (k(d) [dissociation constant] and r(t) [concentration of binding sites]) for these six insect species.201222447600
milling effect on the control efficacy of spray-dried bacillus thuringiensis technical powder against diamondback moths.the relationship between the particle size of spray-dried bacillus thuringiensis nt0423 technical powder and its insecticidal activity against diamondbackmoth was investigated in laboratory and glasshouse conditions. a variety of sizes of bt particles were made by homogenisation, followed by pilot-scale milling to optimise further the current bt formulation process.201222413132
assessment of microbial larvicide spraying with bacillus thuringiensis israelensis, for the prevention of malaria.the aim of this study was to assess the contribution of microbial larvicide spraying, bacillus thuringiensis israelensis, as prevention strategy against malaria.201222405513
functional interactions between members of the repat family of insect pathogen-induced proteins.studies on the transcriptional response to pathogens in the insect larval gut have shown the regulation of several genes after the infection. repat (response to pathogens) genes were first identified in spodoptera exigua midgut as being up-regulated in response to the exposure to bacillus thuringiensis toxins and baculovirus. recently, new members of the repat family showed a constitutive up-regulation in a b. thuringiensis-resistant population. based on a yeast two-hybrid screening, we have det ...201222404489
oxygen supply in bacillus thuringiensis fermentations: bringing new insights on their impact on sporulation and δ-endotoxin production.the growth kinetics, sporulation, and toxicity of bacillus thuringiensis var. israelensis were evaluated through the analysis of batch cultures with different dissolved oxygen (do) profiles. firstly, do was maintained constant at 5%, 20%, or 50% throughout fermentation in order to identify the most suitable one to improve the main process parameters. higher biomass concentration, cell productivity, and cell yield based on glucose were obtained with 50% do. the higher aeration level also resulted ...201222395904
atomic force microscopy: a powerful tool for studying bacterial swarming motility.swarming motility is a fascinating phenomenon by which some bacteria use flagella to move over solid surfaces. understanding the molecular mechanisms underlying swarming motility requires studying the factors that induce and control flagella expression in swarming cells. traditionally, flagella are observed by optical or electron microscopy, but none of these techniques combine versatility and easiness, with quantitative and high-resolution information. we report an atomic force microscopy (afm) ...201222386764
mosquitocidal properties of calotropis gigantea (family: asclepiadaceae) leaf extract and bacterial insecticide, bacillus thuringiensis, against the mosquito vectors.calotropis gigantea leaf extract and bacillus thuringiensis were tested first to fourth-instar larvae and pupae of anopheles stephensi, aedes aegypti, and culex quinquefasciatus. the medicinal plants were collected from the area around bharathiar university, coimbatore, india. calotropis gigantea leaf was washed with tap water and shade-dried at room temperature. an electrical blender powdered the dried plant materials (leaves). the powder 500 g of the leaf was extracted with 1.5 l of organic so ...201222382205
using field-evolved resistance to cry1f maize in a lepidopteran pest to demonstrate no adverse effects of cry1f on one of its major predators.spodoptera frugiperda (je smith) represents the first documented case of field-evolved resistance to a genetically engineered crop expressing an insecticidal protein from bacillus thuringiensis (bt). in this case it was cry1f-expressing maize (mycogen 2a517). the ladybird beetle, coleomegilla maculata, is a common and abundant predator that suppresses pest populations in maize and many other cropping systems. its larvae and adults are polyphagous, feeding on aphids, thrips, lepidopteran eggs and ...201222373893
bacillus thuringiensis protein transfer between rootstock and scion of grafted poplar.bacillus thuringiensis (bt) cry1ac protein is a toxin against different leaf-eating lepidopteran insects that attack poplar trees. in the present study, the mode of migration of the bt-cry1ac protein within poplar grafts was investigated. grafting was done using pb29 (transgenic poplar 741 with cry1ac genes), cc71 (transgenic poplar 741 with cry3a genes), non-transgenic poplar 741 and non-transgenic populus tomentosa, either as scion or as rootstock. in order to detect migration of bt-cry1ac pro ...201222372666
construction of a promoter-probe vector for bacillus thuringiensis: the identification of cis-acting elements of the chia locus.the expression and application of bacillus thuringiensis (bt) chitinase genes have been extensively investigated. however, little information is available regarding the regulation of chitinase gene expression in bt. in this study, a shuttle promoter-probe vector was constructed incorporating the thermostable β-galactosidase gene bgab of b. stearothermophilus as the reporter for the study of bt promoters. using this plasmid, the activity of the chia gene promoter in bt was investigated. deletion ...201222367329
field assessment of bt cry1ah corn pollen on the survival, development and behavior of apis mellifera ligustica.honeybees may be exposed to insecticidal proteins from transgenic plants via pollen. an assessment of the impact of such exposures on the honeybee is an essential part of the risk assessment process for transgenic bacillus thuringiensis corn. a field trial was conducted to evaluate the effect of transgenic bt cry1ah corn on the honeybee apis mellifera ligustica. colonies of honeybees were moved to bt or non-bt corn fields during anthesis and then sampled to record their survival, development and ...201222364780
detection and identification of vegetative insecticidal proteins vip3 genes of bacillus thuringiensis strains using polymerase chain reaction-high resolution melt analysis.in this study, vegetative insecticidal proteins vip3 genes from bacillus thuringiensis strains were detected based on polymerase chain reaction-high resolution melt (pcr-hrm) analysis. a pair of primers was designed according to the conservative sequences in 150 bp region of the known vip3 subfamily. the 150 bp regions of difference vip3 genes have only a few nucleotide difference vip3 genes were detected in 8 of 11 standard b. thuringiensis strains, and vip3aa genes, vip3af genes and vip3ba gen ...201222350000
identifying insecticide resistance genes in mosquito by combining aflp genome scans and 454 pyrosequencing.aflp-based genome scans are widely used to study the genetics of adaptation and to identify genomic regions potentially under selection. however, this approach usually fails to detect the actual genes or mutations targeted by selection owing to the difficulties of obtaining dna sequences from aflp fragments. here, we combine classical aflp outlier detection with 454 sequencing of aflp fragments to obtain sequences from outlier loci. we applied this approach to the study of resistance to bacillus ...201222348648
a scallop c-type lectin from argopecten irradians (aictl5) with activities of lipopolysaccharide binding and gram-negative bacteria agglutination.c-type lectins are a family of calcium-dependent carbohydrate-binding proteins. in the present study, a c-type lectin (designated as aictl5) was identified and characterized from argopecten irradians. the full-length cdna of aictl5 was of 673 bp, containing a 5' untranslated region (utr) of 24 bp, a 3' utr of 130 bp with a poly (a) tail, and an open reading frame (orf) of 519 bp encoding a polypeptide of 172 amino acids with a putative signal peptide of 17 amino acids. a c-type lectin-like domai ...201222342746
a practicable detection system for genetically modified rice by sers-barcoded nanosensors.since the global cultivation of genetically modified crops constantly expands, it remains a high demand to establish different ways to sort food and feed that consist or contain genetically modified organisms. surface-enhanced raman scattering (sers) spectroscopy is a flexible tool for biological analysis due to its excellent properties for detecting wide varieties of target biomolecules including nucleic acids. in the present study, a sers-barcoded nanosensor was developed to detect bacillus th ...201222342698
treatment of an aedes aegypti colony with the cry11aa toxin for 54 generations results in the development of resistance.to study the potential for the emergence of resistance in aedes aegypti populations, a wild colony was subjected to selective pressure with cry11aa, one of four endotoxins that compose the bacillus thuringiensis serovar israelensis toxin. this bacterium is the base component of the most important biopesticide used in the control of mosquitoes worldwide. after 54 generations of selection, significant resistance levels were observed. at the beginning of the selection experiment, the half lethal co ...201222310538
identification of henosepilachna vigintioctomaculata (coleoptera: coccinellidae) midgut putative receptor for bacillus thuringiensis insecticidal cry7ab3 toxin.bt wz-9 strain, containing a single cry7ab3 toxin, had effective insecticidal activity against larvae of henosepilachna vigintioctomaculata. by incubation with larvae midgut homogenate and trypsin in vitro, 130 kda cry7ab3 protoxin was degraded into the ∼75 kda proteinase-resistant fragments. in vivo analysis, 130 kda cry7ab3 protoxin was also processed into ∼75 kda fragment. histopathological observations indicated that cry7ab3 ingestion by h. vigintioctomaculata larvae causes acceleration in t ...201222306353
comparison of quantitative pcr and culture-based methods for evaluating dispersal of bacillus thuringiensis endospores at a bioterrorism hoax crime scene.since the anthrax mail attacks of 2001, law enforcement agencies have processed thousands of suspicious mail incidents globally, many of which are hoax bioterrorism threats. bio-insecticide preparations containing bacillus thuringiensis (bt) spores have been involved in several such threats in australia, leading to the requirement for rapid and sensitive detection techniques for this organism, a close relative of bacillus anthracis. here we describe the development of a quantitative pcr (qpcr) m ...201222227150
low-temperature decontamination with hydrogen peroxide or chlorine dioxide for space applications.the currently used microbial decontamination method for spacecraft and components uses dry-heat microbial reduction at temperatures of >110°c for extended periods to prevent the contamination of extraplanetary destinations. this process is effective and reproducible, but it is also long and costly and precludes the use of heat-labile materials. the need for an alternative to dry-heat microbial reduction has been identified by space agencies. investigations assessing the biological efficacy of tw ...201222492450
cereulide produced by bacillus cereus increases the fitness of the producer organism in low-potassium environments.cereulide, produced by certain bacillus cereus strains, is a lipophilic cyclic peptide of 1152 da that binds k(+) ions with high specificity and affinity. it is toxic to humans, but its role for the producer organism is not known. we report here that cereulide operates for b. cereus to scavenge potassium when the environment is growth limiting for this ion. cereulide-producing b. cereus showed higher maximal growth rates (µ(max)) than cereulide non-producing b. cereus in k(+)-deficient medium (k ...201222241046
superstructure of the centromeric complex of tubzrc plasmid partitioning systems.bacterial plasmid partitioning systems segregate plasmids into each daughter cell. in the well-understood parmrc plasmid partitioning system, adapter protein parr binds to centromere parc, forming a helix around which the dna is externally wrapped. this complex stabilizes the growth of a filament of actin-like parm protein, which pushes the plasmids to the poles. the tubzrc plasmid partitioning system consists of two proteins, tubulin-like tubz and tubr, and a dna centromere, tubc, which perform ...201223010931
the direct repeat sequence upstream of bacillus chitinase genes is cis-acting elements that negatively regulate heterologous expression in e. coli.to explore the influence of the direct repeat sequence (drs) in bacillus chitinase genes on heterogonous expression in escherichia coli, we cloned and sequenced the entire open reading frame (orf) and upstream sequences of the chitinase b (chib) and chitinase my75 (chimy75) from bacillus thuringiensis and bacillus licheniformis. a pair of 8-bp drs was found upstream of each chi gene. chi orfs with a series of truncated drs were cloned and transformed into e. coli xl-blue. the activity of the tra ...201222500893
chitinase production by bacillus thuringiensis and bacillus licheniformis: their potential in antifungal biocontrol.thirty bacterial strains were isolated from the rhizosphere of plants collected from egypt and screened for production of chitinase enzymes. bacillus thuringiensis nm101-19 and bacillus licheniformis nm120-17 had the highest chitinolytic activities amongst those investigated. the production of chitinase by b. thuringiensis and b. licheniformis was optimized using colloidal chitin medium amended with 1.5% colloidal chitin, with casein as a nitrogen source, at 30°c after five days of incubation. a ...201222367944
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
production of protocatechuic acid in bacillus thuringiensis atcc33679.protocatechuic acid, or 3,4-dihydroxybenzoic acid, is produced by both soil and marine bacteria in the free form and as the iron binding component of the siderophore petrobactin. the soil bacterium, bacillus thuringiensis kurstaki atcc 33679, contains the asb operon, but does not produce petrobactin. iron restriction resulted in diminished b. thuringiensis kurstaki atcc 33679 growth and the production of catechol(s). the gene product responsible for protocatechuic acid (asbf) and its receptor (f ...201222489181
sporicidal/bactericidal textiles via the chlorination of silk.bacterial spores, such as those of the bacillus genus, are extremely resilient, being able to germinate into metabolically active cells after withstanding harsh environmental conditions or aggressive chemical treatments. the toughness of the bacterial spore in combination with the use of spores, such as those of bacillus anthracis, as a biological warfare agent necessitates the development of new antimicrobial textiles. in this work, a route to the production of fabrics that kill bacterial spore ...201222352921
bacteria and their toxins tamed for immunotherapy.bacterial toxins share the ability to enter host cells to target various intracellular proteins and to modulate host immune responses. over the last 20 years, toxins and their mutated variants, as well as live attenuated bacteria, have been exploited for vaccination and immunotherapy of various infectious, malignant and autoimmune diseases. the ability of bordetella pertussis adenylate cyclase toxin to translocate its adenylate cyclase domain across the host cell membrane, as well as the pathway ...201222339216
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
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
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
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
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
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
sequence analysis of inducible prophage phis3501 integrated into the haemolysin ii gene of bacillus thuringiensis var israelensis atcc35646.diarrheic food poisoning by bacteria of the bacillus cereus group is mostly due to several toxins encoded in the genomes. one of them, cytotoxin k, was recently identified as responsible for severe necrotic syndromes. cytotoxin k is similar to a class of proteins encoded by genes usually annotated as haemolysin ii (hlyii) in the majority of genomes of the b. cereus group. the partially sequenced genome of bacillus thuringiensis var israelensis atcc35646 contains several potentially induced proph ...201222567391
molecular and toxigenic characterization of bacillus cereus and bacillus thuringiensis strains isolated from commercial ground roasted coffee.thirty samples of roasted ground coffee beans from 10 different commercial brands were analyzed to investigate the occurrence and levels of bacillus cereus and bacillus thuringiensis strains. strains were evaluated for their genetic diversity by repetitive element sequence polymorphism pcr (rep-pcr) and for their toxigenic profiles, i.e., the presence of hbla, hblc, hbld, nhea, nheb, nhec, cytk, ces, and entfm. survival and multiplication of b. cereus sensu lato in the ready-to-drink coffee was ...201222410226
complete genome sequence of the highly hemolytic strain bacillus cereus f837/76.highly hemolytic strain bacillus cereus f837/76 was isolated in 1976 from a contaminated prostate wound. the complete nucleotide sequence of this strain reported here counts nearly 36,500 single-nucleotide differences from the closest sequenced strain, bacillus thuringiensis al hakam. f827/76 also contains a 10-kb plasmid that was not detected in the al hakam strain.201222374959
functional assignment of yvgo, a novel set of purified and chemically characterized proteinaceous antifungal variants produced by bacillus thuringiensis sf361.this study reports a novel class of antifungal protein derived from bacterial origin. bacillus thuringiensis sf361, the strain also responsible for producing the novel bacteriocin thurincin h, exhibits broad antifungal activity against select members of several fungal genera, including aspergillus, byssochlamys, and penicillium, as well as the pathogenic yeast candida albicans. optimal antifungal production and secretion were observed after-log phase growth when incubated at 37°c in a carbohydra ...201222307285
bacterial mixture from greenhouse soil as a biocontrol agent against root-knot nematode, meloidogyne incognita, on oriental melon.the biological control efficacy of a greenhouse soil bacterial mixture of lactobacillus farraginis, bacillus cereus, and bacillus thuringiensis strains with antinematode activity was evaluated against the root-knot nematode meloidogyne incognita. two control groups planted in soil drenched with sterile distilled water or treated with the broadspectrum carbamate pesticide carbofuran were used for comparison. the results suggest that the bacterial mixture is effective as a biocontrol agent against ...201222297227
genetic barcodes for improved environmental tracking of an anthrax simulant.the development of realistic risk models that predict the dissemination, dispersion and persistence of potential biothreat agents have utilized nonpathogenic surrogate organisms such as bacillus atrophaeus subsp. globigii or commercial products such as bacillus thuringiensis subsp. kurstaki. comparison of results from outdoor tests under different conditions requires the use of genetically identical strains; however, the requirement for isogenic strains limits the ability to compare other desira ...201223001658
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
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
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
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
characteristics of a broad lytic spectrum endolysin from phage btcs33 of bacillus thuringiensis.endolysins produced by bacteriophages lyse bacteria, and are thus considered a novel type of antimicrobial agent. several endolysins from bacillus phages or prophages have previously been characterized and used to target bacillus strains that cause disease in animals and humans. b. thuringiensis phage btcs33 is a siphoviridae family phage and its genome has been sequenced and analyzed. in the btcs33 genome, orf18 was found to encode an endolysin protein (plybt33).201223249212
antibiotic producing microorganisms from river wiwi, lake bosomtwe and the gulf of guinea at doakor sea beach, ghana.microorganisms have provided a wealth of metabolites with interesting activities such as antimicrobial, antiviral and anticancer. in this study, a total of 119 aquatic microbial isolates from 30 samples (taken from water bodies in ghana) were screened by the agar-well diffusion method for ability to produce antibacterial-metabolites.201223072432
mechanistic and single-dose in vivo therapeutic studies of cry5b anthelmintic action against hookworms.hookworm infections are one of the most important parasitic infections of humans worldwide, considered by some second only to malaria in associated disease burden. single-dose mass drug administration for soil-transmitted helminths, including hookworms, relies primarily on albendazole, which has variable efficacy. new and better hookworm therapies are urgently needed. bacillus thuringiensis crystal protein cry5b has potential as a novel anthelmintic and has been extensively studied in the roundw ...201223145203
bacterial pore-forming proteins as anthelmintics.crystal (cry) proteins are made by the gram-positive bacterium bacillus thuringiensis (bt). cry proteins are pore-forming proteins and are the most widely used biological insecticides in the world. our laboratory found some cry proteins are highly effective against a broad range of nematodes (roundworms). here, we discuss our results of cry protein activity against intestinal roundworms. both cry5b and cry21a have therapeutic activities against infections of the roundworm heligmosomoides polygyr ...201222562659
differential proteomic analysis of trichoplusia ni cells after continuous selection with activated cry1ac toxin.development of insect resistance to bacillus thuringiensis (bt) toxins threatens the sustained successful application of bt-based biological control tactics. multi-mechanisms of resistance have been proposed, such as alteration of toxin-binding proteins, changes of proteases in midgut and so on. the other responses of the cry1ac-selected insects might also contribute to the evolution of resistance. here, the cry1ac-selected trichoplusia ni tnh5 cells with high resistance were subjected to analys ...201223070538
evolution of bacillus thuringiensis cry toxins insecticidal activity.insecticidal cry proteins produced by bacillus thuringiensis are use worldwide in transgenic crops for efficient pest control. among the family of cry toxins, the three domain cry family is the better characterized regarding their natural evolution leading to a large number of cry proteins with similar structure, mode of action but different insect specificity. also, this group is the better characterized regarding the study of their mode of action and the molecular basis of insect specificity. ...201222463726
fate of bacillus thuringiensis subsp. israelensis in the field: evidence for spore recycling and differential persistence of toxins in leaf litter.bacillus thuringiensis subsp. israelensis is a bioinsecticide increasingly used worldwide for mosquito control. despite its apparent low level of persistence in the field due to the rapid loss of its insecticidal activity, an increasing number of studies suggested that the recycling of b. thuringiensis subsp. israelensis can occur under specific, unknown conditions. decaying leaf litters sampled in mosquito breeding sites in the french rhône-alpes region several months after a treatment were sho ...201223001669
proteome analysis of cry4ba toxin-interacting aedes aegypti lipid rafts using gelc-ms/ms.lipid rafts are microdomains in the plasma membrane of eukaryotic cells. among their many functions, lipid rafts are involved in cell toxicity caused by pore forming bacterial toxins including bacillus thuringiensis (bt) cry toxins. we isolated lipid rafts from brush border membrane vesicles (bbmv) of aedes aegypti larvae as a detergent resistant membrane (drm) fraction on density gradients. cholesterol, aminopeptidase (apn), alkaline phosphatase (alp) and the raft marker flotillin were preferen ...201223153095
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
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
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
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
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
characterization of insecticidal genes of bacillus thuringiensis strains isolated from arid environments.this study aimed at characterizing the insecticidal genes of eight bacillus thuringiensis isolates that were recovered from the local environment of western saudi arabia. the screening for the presence of lepidopteran-specific cry1a family and vip3a genes, dipteran-specific cry4 family and coleopteran-specific cry3a, vip1a and vip2a genes, was carried out by pcr. all eight isolates produced pcr products that confirmed the presence of cry1aa, cry1ab, cry1ac, cry4a, cry4b genes, but not cry3a, vip ...201223997347
cry1aa binding to the cadherin receptor does not require conserved amino acid sequences in the domain ii loops.characterizing the binding mechanism of bt (bacillus thuringiensis) cry toxin to the cadherin receptor is indispensable to understanding the specific insecticidal activity of this toxin. to this end, we constructed 30 loop mutants by randomly inserting four serial amino acids covering all four receptor binding loops (loops α8, 1, 2 and 3) and analysed their binding affinities for bombyx mori cadherin receptors via biacore. high binding affinities were confirmed for all 30 mutants containing loop ...201223145814
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
the susceptibility of five african anopheles species to anabaena pcc 7120 expressing bacillus thuringiensis subsp. israelensis mosquitocidal cry genes.malaria, one of the leading causes of death in africa, is transmitted by the bite of an infected female anopheles mosquito. problems associated with the development of resistance to chemical insecticides and concerns about the non-target effects and persistence of chemical insecticides have prompted the development of environmentally friendly mosquito control agents. the aim of this study was to evaluate the larvicidal activity of a genetically engineered cyanobacterium, anabaena pcc 7120#11, ag ...201223036082
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