| specificity determinants for cry insecticidal proteins: insights from their mode of action. | insecticidal proteins from the bacterium bacillus thuringiensis (bt) are used as active components of biopesticides and as plant incorporated protectants in transgenic crops. one of the most relevant attributes of these bt protein-based insecticidal technologies is their high specificity, which assures lack of detrimental effects on non-target insects, vertebrates and the environment. the identification of specificity determinants in bt insecticidal proteins could guide risk assessment for novel ... | 2017 | 27480404 |
| structural classification of insecticidal proteins - towards an in silico characterisation of novel toxins. | the increasing rate of discovery of new toxins with potential for the control of invertebrate pests through next generation sequencing, presents challenges for the identification of the best candidates for further development. a consideration of structural similarities between the different toxins suggest that they may be functionally less diverse than their low sequence similarities might predict. this is encouraging from the prospective of being able to use computational tools to predict toxin ... | 2017 | 27480403 |
| vip3aa induces apoptosis in cultured spodoptera frugiperda (sf9) cells. | the vegetative insecticidal proteins (vip) secreted by many bacillus thuringiensis strains during their vegetative growth stage are regarded as second generation insecticidal proteins, as they share no sequence or structural homology with known crystal insecticidal proteins (cry) and have a broad insecticidal spectrum. compared with insecticidal crystal proteins (icps), the insecticidal mechanisms of vips have been little studied. here we investigated the mechanism responsible for vip3aa toxicit ... | 2016 | 27476462 |
| coprinopsis cinerea intracellular lactonases hydrolyze quorum sensing molecules of gram-negative bacteria. | biofilm formation on fungal hyphae and production of antifungal molecules are strategies of bacteria in their competition with fungi for nutrients. since these strategies are often coordinated and under control of quorum sensing by the bacteria, interference with this bacterial communication system can be used as a counter-strategy by the fungi in this competition. hydrolysis of n-acyl-homoserine lactones (hsl), a quorum sensing molecule used by gram-negative bacteria, by fungal cultures has bee ... | 2016 | 27475110 |
| conditions for homogeneous preparation of stable monomeric and oligomeric forms of activated vip3a toxin from bacillus thuringiensis. | bacillus thuringiensis vegetative insecticidal proteins like vip3a have been used for crop protection and to delay resistance to existing insecticidal cry toxins. however, little is known about vip3a's behavior or its mechanism of action, and a structural model is required. herein, in an effort to facilitate future crystallization and functional studies, we have used the orthogonal biophysical techniques of light scattering and sedimentation to analyze the aggregation behavior and stability of t ... | 2017 | 27473845 |
| three toxins, two receptors, one mechanism: mode of action of cry1a toxins from bacillus thuringiensis in heliothis virescens. | insecticidal crystal (cry) proteins from bacillus thuringiensis (bt) are highly active against lepidoptera. however, field-evolved resistance to bt toxins is on the rise. the 12-cadherin domain protein hevcalp and the abc transporter hevabcc2 are both genetically linked to cry toxin resistance in heliothis virescens. we investigated their interaction using stably expressing non-lytic clonal sf9 cell lines expressing either protein or both together. untransfected sf9 cells are innately sensitive ... | 2016 | 27456115 |
| cry1ac toxicity enhancement towards lepidopteran pest ephestia kuehniella through its protection against excessive proteolysis. | bacillus thuringiensis has been extensively used in agroecosystems for four decades due to its high specific toxicity. strategies based on b. thuringiensis proteins combinations for the improvement of its activity present an important focus for biopesticides development. however, the widespread use of b. thuringiensis δ-endotoxins has often been challenged by a lack of understanding of the target insect physiology as well as its midgut biochemistry. in the present investigation, we have evidence ... | 2016 | 27452929 |
| cry1ab-expressing rice did not influence expression of fecundity-related genes in the wolf spider pardosa pseudoannulata. | the impact of bacillus thuringiensis (bt) toxin proteins on non-target predatory arthropods is not well understood at the cellular and molecular levels. here, we investigated the potential effects of cry1ab expressing rice on fecundity of the wolf spider, pardosa pseudoannulata, and some of the underlying molecular mechanisms. the results indicated that brown planthoppers (bphs) reared on cry1ab-expressing rice accumulated the cry toxin and that reproductive parameters (pre-oviposition period, p ... | 2016 | 27452121 |
| routine implementation costs of larviciding with bacillus thuringiensis israelensis against malaria vectors in a district in rural burkina faso. | the key tools in malaria control are early diagnosis and treatment of cases as well as vector control. current strategies for malaria vector control in sub-saharan africa are largely based on long-lasting insecticide-treated nets (llins) and to a much smaller extent on indoor residual spraying (irs). an additional tool in the fight against malaria vectors, larval source management (lsm), has not been used in sub-saharan africa on a wider scale since the abandonment of environmental spraying of d ... | 2016 | 27449023 |
| silver nanoparticles production by two soil isolated bacteria, bacillus thuringiensis and enterobacter cloacae, and assessment of their cytotoxicity and wound healing effect in rats. | production of silver nanoparticles by bacillus thuringiensis and enterobacter cloacae was performed and confirmed through uv-visible spectrophotometry, transmission electron microscopy (tem), and x-ray diffraction (xrd) analyses. the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (mtt) assay using mouse fibroblast cell line nih-3t3 d4 was carried out and ic50s of agnps were obtained. the nontoxic dose of each agnps solution was selected for wound healing assay. thirty-two rats were ... | 2016 | 27448276 |
| microbial biofertilizer decreases nicotine content by improving soil nitrogen supply. | biofertilizers have been widely used in many countries for their benefit to soil biological and physicochemical properties. a new microbial biofertilizer containing phanerochaete chrysosporium and bacillus thuringiensis was prepared to decrease nicotine content in tobacco leaves by regulating soil nitrogen supply. soil no3(-)-n, nh4(+)-n, nitrogen supply-related enzyme activities, and nitrogen accumulation in plant leaves throughout the growing period were investigated to explore the mechanism o ... | 2017 | 27439003 |
| potential resistance management for the sustainable use of insect-resistant genetically modified corn and rice in china. | many lines of insect-resistant genetically modified (irgm) corn and rice containing bacillus thuringiensis (bt) insecticidal genes have been developed and undergone different environmental biosafety assessments stages in china, showing robust application prospects. the potential of targeted pests to develop resistance to bt crops is widespread, which threatens the sustainable utility of irgm corn and rice. in this study, the potential risks of target pest complexes developing resistance to irgm ... | 2016 | 27436744 |
| current situation of pests targeted by bt crops in latin america. | transgenic crops producing bacillus thuringiensis- (bt) insecticidal proteins (bt crops) have provided useful pest management tools to growers for the past 20 years. planting bt crops has reduced the use of synthetic insecticides on cotton, maize and soybean fields in 11 countries throughout latin america. one of the threats that could jeopardize the sustainability of bt crops is the development of resistance by targeted pests. governments of many countries require vigilance in measuring changes ... | 2016 | 27436743 |
| cry1f resistance among lepidopteran pests: a model for improved resistance management? | the cry1fa protein from the bacterium bacillus thuringiensis (bt) is known for its potential to control lepidopteran pests, especially through transgenic expression in maize and cotton. the maize event tc1507 expressing the cry1fa toxin gene became commercially available in the united states in 2003 for the management of key lepidopteran pests including the european corn borer, ostrinia nubilalis, and the fall armyworm, spodoptera frugiperda. a high-dose/refuge strategy has been widely adopted t ... | 2016 | 27436741 |
| resistance to bt maize by western corn rootworm: insights from the laboratory and the field. | western corn rootworm is a serious pest of maize. beginning in 2003, management of western corn rootworm included transgenic maize that produces insecticidal toxins derived from the bacterium bacillus thuringiensis (bt). the first bt maize hybrids produced cry3bb1, but additional bt toxins have since been introduced, including ecry3.1ab, mcry3a and cry34/35ab1. laboratory selection experiments found that western corn rootworm could develop resistance to all types of bt maize following three to s ... | 2016 | 27436740 |
| intestinal regeneration as an insect resistance mechanism to entomopathogenic bacteria. | the intestinal epithelium of insects is exposed to xenobiotics and entomopathogens during the feeding developmental stages. in these conditions, an effective enterocyte turnover mechanism is highly desirable to maintain integrity of the gut epithelial wall. as in other insects, the gut of lepidopteran larvae have stem cells that are capable of proliferation, which occurs during molting and pathogenic episodes. while much is known on the regulation of gut stem cell division during molting, there ... | 2016 | 27436739 |
| susceptibility, mechanisms of response and resistance to bacillus thuringiensis toxins in spodoptera spp. | bioinsecticides based on bacillus thuringiensis have long been used as an alternative to synthetic insecticides to control insect pests. in this review, we focus on insects of the genus spodoptera, including relevant polyphagous species that are primary and secondary pests of many crops, and how b. thuringiensis toxins can be used for spodoptera spp. pest management. we summarize the main findings related to susceptibility, midgut binding specificity, mechanisms of response and resistance of thi ... | 2016 | 27436737 |
| bacillus thuringiensis resistance in plutella - too many trees? | plutella xylostella was the first insect for which resistance to bacillus thuringiensis was reported in the field, yet despite many studies on the nature of this resistance phenotype its genetic and molecular basis remains elusive. many different factors have been proposed as contributing to resistance, although in many cases it has not been possible to establish a causal link. indeed, there are so many studies published that it has become very difficult to 'see the wood for the trees'. this art ... | 2016 | 27436736 |
| bacillus thuringiensis toxin resistance mechanisms among lepidoptera: progress on genomic approaches to uncover causal mutations in the european corn borer, ostrinia nubilalis. | transgenic plants that express bacillus thuringiensis (bt) crystal (cry) protein toxins (bt crops) effectively control feeding by the european corn borer, ostrinia nubilalis, although documented resistance evolution among a number of species in both the laboratory and field has heightened concerns about the durability of this technology. research has provided major insights into the mutations that alter bt toxin binding receptor structure and function within the midgut of lepidoptera that direct ... | 2016 | 27436734 |
| receptors are affected by selection with each bacillus thuringiensis israelensis cry toxin but not with the full bti mixture in aedes aegypti. | bacillus thuringiensis israelensis (bti) toxins are increasingly used for mosquito control, but little is known about the precise mode of action of each of these toxins, and how they interact to kill mosquito larvae. by using rna sequencing, we investigated change in gene transcription level and polymorphism variations associated with resistance to each bti cry toxin and to the full bti toxin mixture in the dengue vector aedes aegypti. the up-regulation of genes related to chitin metabolism in a ... | 2016 | 27418233 |
| selection and characterization of bacillus thuringiensis (berliner) (eubacteriales: bacillaceae) strains for ecdytolopha aurantiana (lima) (lepidoptera: tortricidae) control. | the citrus fruit borer, ecdytolopha aurantiana (lima, 1927) (lepidoptera: tortricidae), is responsible for major losses to the citrus industry because it causes rot and drop of fruits. the current study aimed to select and characterize bacillus thuringiensis (berliner, 1911) strains toxic to e. aurantiana. for this purpose, 47 b. thuringiensis strains were evaluated in selective bioassays using first instar larvae of e. aurantiana. the lethal concentration (lc50) of the most toxic strains was es ... | 2017 | 27406593 |
| sox transcription in sarcosine utilization is controlled by sigma(54) and soxr in bacillus thuringiensis hd73. | sarcosine oxidase catalyzes the oxidative demethylation of sarcosine to yield glycine, formaldehyde, and hydrogen peroxide. in this study, we analyzed the transcription and regulation of the sox locus, including the sarcosine oxidase-encoding genes in bacillus thuringiensis (bt). rt-pcr analysis revealed that the sox locus forms two opposing transcriptional units: soxb (soxb/e/f/g/h/i) and soxr (soxr/c/d/a). the typical -12/-24 consensus sequence was located 15 bp and 12 bp from the transcriptio ... | 2016 | 27404799 |
| efficacy of soybean's event das-81419-2 expressing cry1f and cry1ac to manage key tropical lepidopteran pests under field conditions in brazil. | bacillus thuringiensis (bt) event das-81419-2 (conkesta technology) in soybean, glycine max (l.) merrill, expresses cry1f and cry1ac proteins to provide protection from feeding by several lepidopteran pests. a total of 27 field experiments across nine locations were conducted from 2011 to 2015 in southern and central brazil to characterize the efficacy of das-81419-2 soybean infested with anticarsia gemmatalis hübner (lepidoptera: erebidae), chrysodeixis includens (walker) (lepidoptera: noctuida ... | 2016 | 27401112 |
| distribution and metabolism of bt-cry1ac toxin in tissues and organs of the cotton bollworm, helicoverpa armigera. | crystal (cry) proteins derived from bacillus thuringiensis (bt) have been widely used in transgenic crops due to their toxicity against insect pests. however, the distribution and metabolism of these toxins in insect tissues and organs have remained obscure because the target insects do not ingest much toxin. in this study, several cry1ac-resistant strains of helicoverpa armigera, fed artificial diets containing high doses of cry1ac toxin, were used to investigate the distribution and metabolism ... | 2016 | 27399776 |
| cry1ac toxin induces macrophage activation via erk1/2, jnk and p38 mitogen-activated protein kinases. | the cry1ac toxin from bacillus thuringiensis is used commercially as a bio-insecticide and is expressed in transgenic plants that are used for human and animal consumption. although it was originally considered innocuous for mammals, the cry1ac toxin is not inert and has the ability to induce mucosal and systemic immunogenicity. herein, we examined whether the cry1ac toxin promotes macrophage activation and explored the signalling pathways that may mediate this effect. treatment of primary and r ... | 2016 | 27394658 |
| high expression of cry1ac protein in cotton (gossypium hirsutum) by combining independent transgenic events that target the protein to cytoplasm and plastids. | transgenic cotton was developed using two constructs containing a truncated and codon-modified cry1ac gene (1,848 bp), which was originally characterized from bacillus thuringiensis subspecies kurstaki strain hd73 that encodes a toxin highly effective against many lepidopteran pests. in construct i, the cry1ac gene was cloned under fmvde, a strong constitutively expressing promoter, to express the encoded protein in the cytoplasm. in construct ii, the encoded protein was directed to the plastids ... | 2016 | 27391960 |
| effects of transgenic bt rice on nontarget rhopalosiphum maidis (homoptera: aphididae). | the effects of three transgenic bacillus thuringiensis (bt) rice lines, kmd1, kmd2, and g8-7, on biological parameters and population dynamics of nontarget insect, rhopalosiphum maidis (fitch) (homoptera: aphididae), were investigated in the laboratory and field. no significant differences were found between bt and non-bt rice lines for aphid survival. the developmental time of r. maidis that fed on kmd1 and kmd2 did not differ significantly from those of the individuals feeding on the parental ... | 2016 | 27389683 |
| [the analysis of major metabolic pathways in bacillus thuringiensis under alkaline stress]. | the study aimed to determine the appropriate stage for exploring the responseof bacillus thuringiensis to the alkaline stress, to profile the metabolic pathways under this stress. | 2016 | 27382791 |
| crystal structure of cry6aa: a novel nematicidal clya-type α-pore-forming toxin from bacillus thuringiensis. | crystal (cry) proteins from bacillus thuringiensis (bt) are globally used in agriculture as proteinaceous insecticides. numerous crystal structures have been determined, and most exhibit conserved three-dimensional architectures. recently, we have identified a novel nematicidal mechanism by which cry6aa triggers cell death through a necrosis-signaling pathway via an interaction with the host protease asp-1. however, we found little sequence conservation of cry6aa in our functional study. here, w ... | 2016 | 27381865 |
| cyclic di-gmp contributes to adaption and virulence of bacillus thuringiensis through a riboswitch-regulated collagen adhesion protein. | cyclic di-gmp is a ubiquitous second messenger that regulates diverse cellular processes in bacteria by binding to various protein or riboswitch effectors. in bacillus thuringiensis bmb171, a c-di-gmp riboswitch termed bc2 rna resides in the 5'-untranslated region (5'-utr) of an mrna that encodes a collagen adhesion protein (cap). the expression of cap was strongly repressed in parent strain bmb171 because of the presence of bc2 rna but was significantly promoted in the bc2 rna markerless deleti ... | 2016 | 27381437 |
| toxicity of bacillus thuringiensis crystal proteins against eri silkworm, samia cynthia ricini (lepidoptera: saturniidae). | ten purified crystal proteins of bacillus thuringiensis (bt) were tested at concentrations ranging from 2.93 to 3000ng/cm(2) for their toxicity to eri silkworm through protein paint bioassays using castor leaves. based on lc50 values, cry1aa (2.6ng/cm(2)) was highly toxic followed by cry1ac (29.3ng/cm(2)) and cry1ab (68.7ng/cm(2)). the cry1ca and cry1ea proteins were moderately toxic to eri silkworm larvae and resulted in 23% and 28% mortality, respectively at the highest concentration tested (3 ... | 2016 | 27377590 |
| histochemical effects of some biological agents on culex pipiens larvae. | the histochemical effects of the lethal concentration that kills 50% of larvae (lc50) of three biological agents, abamectin, bacillus thuringiensis and spinosad on the carbohydrates (polysaccharides), proteins, nucleic acids and lipids content of the midgut and fat bodies of culex pipiens 2nd instar larvae were studied. the results showed that the three tested compounds reduced the carbohydrates (polysaccharides), proteins, rna synthesis and lipids content after 72 hours of treatment where abame ... | 2016 | 27363043 |
| bacillus thuringiensis b1(2015b) is a gram-positive bacteria able to degrade naproxen and ibuprofen. | a gram-positive bacterium, designated as strain b1(2015b), was isolated from the soil of the chemical factory "organika-azot" in jaworzno, poland. on the basis of 16s rrna gene sequence analysis, the isolated strain was classified as a bacillus thuringiensis species. strain b1(2015b) is able to degrade ibuprofen and naproxen, however, these compounds are not sufficient carbon sources for this strain. in the presence of glucose, bacillus thuringiensis b1(2015b) degrades ibuprofen and naproxen wit ... | 2017 | 27358504 |
| diversity and toxicity of bacillus thuringiensis from shifting cultivation (jhum) habitat. | bacillus thuringiensis (bt) strains were isolated from jhum-agriculture, jhum-forest, aquatic and fallow soil samples from mizoram by acetate selection method. isolates were characterized for biochemical typing, cry gene and protein profiling, growth curve study and toxicity against culex tritaeniorhynchus. bt frequency was high in jhum-agriculture land (69.56%) whereas low in jhum-forest soils (31.57%). bt was found to be abundant in jhum shifting cultivation soil with an index ranging between ... | 2016 | 27350428 |
| effects of transgenic cry1ie maize on non-lepidopteran pest abundance, diversity and community composition. | non-lepidopteran pests are exposed to, and may be influenced by, bt toxins when feeding on bt maize that express insecticidal cry proteins derived from bacillus thuringiensis (bt). in order to assess the potential effects of transgenic cry1ie maize on non-lepidopteran pest species and ecological communities, a 2-year field study was conducted to compare the non-lepidopteran pest abundance, diversity and community composition between transgenic cry1ie maize (event ie09s034, bt maize) and its near ... | 2016 | 27344564 |
| functional validation of cadherin as a receptor of bt toxin cry1ac in helicoverpa armigera utilizing the crispr/cas9 system. | cadherins have been identified as receptors of bacillus thuringiensis (bt) cry1a toxins in several lepidopteran insects including the cotton bollworm, helicoverpa armigera. disruption of the cadherin gene hacad has been genetically linked to resistance to bt toxin cry1ac in h. armigera. by using the crispr/cas9 genome editing system (clustered regularly interspaced short palindromic repeats/crispr-associated protein 9), hacad from the cry1ac-susceptible scd strain of h. armigera was successfully ... | 2016 | 27343383 |
| a 52-week safety study in cynomolgus macaques for genetically modified rice expressing cry1ab/1ac protein. | a 52-week feeding study in cynomolgus macaques was carried out to evaluate the safety of bt rice huahui 1 (hh1), a transgenic rice line expressing cry1ab/1ac protein. monkeys were fed a diet with 20% or 60% hh1 rice, 20% or 60% parental rice (minghui 63, mh63), normal diet, normal diet spiked with purified recombinant cry1ab/1ac fusion protein or bovine serum albumin (bsa) respectively. during the feeding trail, clinical observations were conducted daily, and multiple parameters, including body ... | 2016 | 27338709 |
| rnai induced knockdown of a cadherin-like protein (ef531715) does not affect toxicity of cry34/35ab1 or cry3aa to diabrotica virgifera virgifera larvae (coleoptera: chrysomelidae). | the western corn rootworm (wcr), diabrotica virgifera virgifera leconte, is an important maize pest throughout most of the u.s. corn belt. bacillus thuringiensis (bt) insecticidal proteins including modified cry3aa and cry34/35ab1 have been expressed in transgenic maize to protect against wcr feeding damage. to date, there is limited information regarding the wcr midgut target sites for these proteins. in this study, we examined whether a cadherin-like gene from diabrotica virgifera virgifera (d ... | 2016 | 27334721 |
| sequencing, de novo assembly and annotation of a pink bollworm larval midgut transcriptome. | the pink bollworm pectinophora gossypiella (saunders) (lepidoptera: gelechiidae) is one of the world's most important pests of cotton. insecticide sprays and transgenic cotton producing toxins of the bacterium bacillus thuringiensis (bt) are currently used to manage this pest. bt toxins kill susceptible insects by specifically binding to and destroying midgut cells, but they are not toxic to most other organisms. pink bollworm is useful as a model for understanding insect responses to bt toxins, ... | 2016 | 27333791 |
| impact of lepidoptera (crambidae, noctuidae, and pyralidae) pests on corn containing pyramided bt traits and a blended refuge in the southern united states. | blended refuge for transgenic plants expressing bacillus thuringiensis (bt) toxins has been approved in the northern united states as a resistance management strategy alternative to a structured refuge. a three-year study (2012-2014) was conducted with 54 trials across nine states in the southern united states to evaluate plant injury from lepidopteran pests of corn and yield in a corn hybrid expressing cry1f × cry1ab × vip3aa20 (pioneer brand optimum leptra) planted as a pure stand and in refug ... | 2016 | 27329627 |
| field performance of bt eggplants (solanum melongena l.) in the philippines: cry1ac expression and control of the eggplant fruit and shoot borer (leucinodes orbonalis guenée). | plants expressing cry proteins from the bacterium, bacillus thuringiensis (bt), have become a major tactic for controlling insect pests in maize and cotton globally. however, there are few bt vegetable crops. eggplant (solanum melongena) is a popular vegetable grown throughout asia that is heavily treated with insecticides to control the eggplant fruit and shoot borer, leucinodes orbonalis (efsb). herein we provide the first publicly available data on field performance in asia of eggplant engine ... | 2016 | 27322533 |
| toxicity of bacillus thuringiensis (l.) cry proteins against summer fruit tortrix (adoxophyes orana - fischer von rösslerstamm). | the activity of seven cry1, one cry9 and one hybrid cry1 protoxins against neonate larvae of summer fruit tortrix (adoxophyes orana - fischer von rösslerstamm) has been investigated. cry1ia is identified as the most toxic protein, followed by cry1aa and cry1ac. cry1ca, cry1cb, cry1da and cry1fa were less active, while sn19 (cry1 hybrid protein with domain composition 1ba/1ia/1ba) and cry9aa exhibited negligible toxicity against a. orana. in vitro trypsin-activated cry1ac is still less active tha ... | 2016 | 27311897 |
| f2 screen for resistance to bacillus thuringiensis cry2ab2-maize in field populations of spodoptera frugiperda (lepidoptera: noctuidae) from the southern united states. | the fall armyworm, spodoptera frugiperda (j. e. smith) (lepidoptera: noctuidae), is a target pest of transgenic maize and cotton expressing bacillus thuringiensis (bt) proteins in both north and south america. in 2013 and 2014, a total of 215 f2 two-parent families of s. frugiperda were established using single-pair mating of field individuals collected from seven locations in four states of the southern u.s.: texas, louisiana, georgia, and florida. the objective of the investigation was to dete ... | 2016 | 27311896 |
| replicates, read numbers, and other important experimental design considerations for microbial rna-seq identified using bacillus thuringiensis datasets. | rna-seq is being used increasingly for gene expression studies and it is revolutionizing the fields of genomics and transcriptomics. however, the field of rna-seq analysis is still evolving. therefore, we specifically designed this study to contain large numbers of reads and four biological replicates per condition so we could alter these parameters and assess their impact on differential expression results. bacillus thuringiensis strains atcc10792 and ct43 were grown in two luria broth medium l ... | 2016 | 27303383 |
| comparative analysis of genomics and proteomics in the new isolated bacillus thuringiensis x022 revealed the metabolic regulation mechanism of carbon flux following cu(2+) treatment. | bacillus thuringiensis (bt) x022 is a novel strain isolated from soil in china, and showed strong insecticidal activity against several lepidopteran pests. in this work, we performed whole genome sequencing of this bt strain using the next-generation sequencing technology, and further conducted a comparative analysis with the proteomics data of the specific spore-release period based on lc-ms/ms approach. the bt x022 genome consisted of one circular chromosomal dna and seven plasmids, which were ... | 2016 | 27303381 |
| performance and cross-crop resistance of cry1f-maize selected spodoptera frugiperda on transgenic bt cotton: implications for resistance management. | transgenic crops producing bacillus thuringiensis (bt) proteins have become a primary tool in pest management. due to the intensive use of bt crops, resistance of the fall armyworm, spodoptera frugiperda, to cry1f maize has occurred in puerto rico, brazil, and some areas of the southeastern u.s. the sustainability of bt crops faces a great challenge because the cry1f-maize resistant s. frugiperda may also infest other bt crops in multiple cropping ecosystems. here we examined the survival and pl ... | 2016 | 27301612 |
| broad-spectrum resistance to bacillus thuringiensis toxins by western corn rootworm (diabrotica virgifera virgifera). | the evolution of resistance and cross-resistance threaten the sustainability of genetically engineered crops that produce insecticidal toxins derived from the bacterium bacillus thuringiensis (bt). western corn rootworm, diabrotica virgifera virgifera leconte, is a serious pest of maize and has been managed with bt maize since 2003. we conducted laboratory bioassays with maize hybrids producing bt toxins cry3bb1, mcry3a, ecry3.1ab, and cry34/35ab1, which represent all commercialized bt toxins fo ... | 2016 | 27297953 |
| assessment of bt trait purity in different generations of transgenic cottons. | adequate expression of bt (bacillus thuringiensis) toxins and purity of seeds of bt-transgenic cottons are important for controlling bollworms, and thereby increasing the cotton productivity. therefore, we examined the variability in expression of bt toxin proteins in the seeds and in leaves of different cotton (gossypium hirsutum (l.) hybrids (jkch 226, jkch 1947, jkch durga, jkch ishwar, jkch varun kdchh 441 and kdchh 621) expressing bt toxins in f₁ and f₂ generations, using bioassays against ... | 2016 | 27295920 |
| peptide isolated from cry1ab16 toxin present in bacillus thuringiensis: synthesis and morphology data for layer-by-layer films studied by atomic force microscopy. | the peptide pcl342-354c was obtained from the cry1ab16 toxin present in bacillus thuringiensis ("computational modeling deduced three dimensional structure of cry1ab16 toxin from b. thuringiensis ac11" (kashyap, 2012) [1]). in this data article, we report the synthesis and characterization of the pcl342-354c peptide by maldi-tof/tof mass spectrometry. in addition, the preparation of layer-by-layer films is shown based on interspersion of this peptide with both polyethylenimine (pei) and poly(sod ... | 2016 | 27294178 |
| preliminary report on the reduction of adult mosquitoes in housing compounds in western kenya using the provector flower and entobac bait pads containing bacillus thuringiensis israelensis with honey bait. | reducing mosquito populations indoors and outdoors can have a significant impact on malaria and other mosquito-borne diseases. a new formulation and delivery system for bacillus thuringiensis israelensis (bti) was tested against adult mosquitoes. one entobac bait with 7% bti in a honey solution was placed within each provector flower applicator. the applicators were placed in nine housing compounds, one on the outside of each home in ahero and nyalenda, kenya, in june 2009. seven housing compoun ... | 2016 | 27282815 |
| identification of an alkaline phosphatase as a putative cry1ac binding protein in ostrinia furnacalis (guenée). | asian corn borer (acb), ostrinia furnacalis, is an important insect pest of maize susceptible to different cry1a toxins. based on amino acid sequence alignment of alp sequences from lepidopteran larvae an alp gene was cloned from acb, named ofalp. pull dawn assays using biotinylated cry1ac and brush border membrane vesicles isolated from second instar acb larvae showed that four proteins of 50, 65, 68 and 70kda precipitated with the cry1ac. the 65kda band cross-reacted with the anti-ofalp monocl ... | 2016 | 27265829 |
| localization and in silico study of the vegetative insecticidal proteins vip2s-vip1s of bacillus thuringiensis. | the bacillus thuringiensis s1/4 strain was previously found to harbour vip1s, vip2s, and vip3 genes. its plasmid curing led to the obtaining of four partially cured strains s1/4-2, s1/4-3, s1/4-7, and s1/4-9 (vip2s-vip1s (-), vip3 (+)), one strain s1/4-4 (vip2s-vip1s (+), vip3 (-)), and s1/4-0 strain lacking the three genes. using these derivative strains as templates, pcr amplification and southern blot assay revealed that vip2s-vip1s operon and vip3 gene were localized on two different large p ... | 2016 | 27264647 |
| activation of bt protoxin cry1ac in resistant and susceptible cotton bollworm. | crystalline (cry) proteins from bacillus thuringiensis (bt) are used extensively for insect control in sprays and transgenic plants, but their efficacy is reduced by evolution of resistance in pests. here we evaluated reduced activation of cry1ac protoxin as a potential mechanism of resistance in the invasive pest helicoverpa armigera. based on the concentration killing 50% of larvae (lc50) for a laboratory-selected resistant strain (lf120) divided by the lc50 for its susceptible parent strain ( ... | 2016 | 27257885 |
| life-history traits of spodoptera frugiperda populations exposed to low-dose bt maize. | exposure to bacillus thuringiensis (bt) toxins in low- and moderate-dose transgenic crops may induce sublethal effects and increase the rate of bt resistance evolution, potentially compromising control efficacy against target pests. we tested this hypothesis using the fall armyworm spodoptera frugiperda, a major polyphagous lepidopteran pest relatively tolerant to bt notorious for evolving field-relevant resistance to single-gene bt maize. late-instar larvae were collected from bt cry1ab and non ... | 2016 | 27243977 |
| isolation and characterization of a new bacillus thuringiensis strain with a promising toxicity against lepidopteran pests. | insecticides derived from bacillus thuringiensis are gaining worldwide importance as environmentally desirable alternatives to chemicals for the control of pests in public health and agriculture. isolation and characterization of new strains with higher and broader spectrum of activity is an ever growing field. in the present work, a novel tunisian b. thuringiensis isolate named blb459 was characterized and electrophoresis assay showed that among a collection of 200 b. thuringiensis strains, the ... | 2017 | 27242138 |
| microbiology of cooked and dried edible mediterranean field crickets (gryllus bimaculatus) and superworms (zophobas atratus) submitted to four different heating treatments. | to increase the shelf life of edible insects, modern techniques (e.g. freeze-drying) add to the traditional methods (degutting, boiling, sun-drying or roasting). however, microorganisms become inactivated rather than being killed, and when rehydrated, many return to vegetative stadia. crickets (gryllus bimaculatus) and superworms (zophobas atratus) were submitted to four different drying techniques (t1 = 10' cooking, 24 h drying at 60℃; t2 = 10' cooking, 24 h drying at 80℃; t3 = 30' cooking, 12 ... | 2017 | 27235993 |
| the sequence, structural, and functional diversity within a protein family and implications for specificity and safety: the case for etx_mtx2 insecticidal proteins. | the need for sustainable insect pest control is driving the investigation and discovery of insecticidal proteins outside of the typical 3-domain cry protein family from bacillus thuringiensis (bt). examples include cry35 and cry51 that belong to protein families (toxin_10, etx_mtx2) sharing a common β-pore forming structure and function with known mammalian toxins such as epsilon toxin (etx). although β-pore forming proteins are related to mammalian toxins, there are key differences in sequence ... | 2017 | 27235983 |
| bioinsecticide and leaf litter combination increases oviposition and reduces adult recruitment to create an effective ovitrap for culex mosquitoes. | mosquito egg traps, aquatic habitats baited with oviposition attractant and insecticide, are important tools for surveillance and control efforts in integrated vector management programs. the bioinsecticide bacillus thuringiensis subsp. israelensis (bti) is increasingly used as an environmentally friendly alternative to chemical insecticides and the combination of bti with a simple oviposition attractant like leaf litter to create an effective egg trap seems appealing. however, previous research ... | 2016 | 27232134 |
| effects of bt-transgenic rice cultivation on planktonic communities in paddy fields and adjacent ditches. | the non-target effects of transgenic plants are issues of concern; however, their impacts in cultivated agricultural fields and adjacent natural aquatic ecosystems are poorly understood. we conducted field experiments during two growing seasons to determine the effects of cultivating bacillus thuringiensis (bt)-transgenic rice on the phytoplankton and zooplankton communities in a paddy field and an adjacent ditch. bt toxin was detected in soil but not in water. water quality was not significantl ... | 2016 | 27219503 |
| synthetic predator cues impair immune function and make the biological pesticide bti more lethal for vector mosquitoes. | the control of vector mosquitoes is one of the biggest challenges facing humankind with the use of chemical pesticides often leading to environmental impact and the evolution of resistance. although to a lesser extent, this also holds for bacillus thuringiensis israelensis (bti), the most widely used biological pesticide to control mosquito populations. this raises the need for the development of integrated pest management strategies that allow the reduction of bti concentrations without loss of ... | 2016 | 27209779 |
| molecular cloning, expression, and identification of bre genes involved in glycosphingolipids synthesis in helicoverpa armigera (lepidoptera: noctuidae). | glycosphingolipids (gsls) play important roles in the cellular biology of vertebrate and invertebrate organisms, such as cell differentiation, tumor metastasis, and cell coordination. gsls also serve as receptors for different bacterial toxins. for example, in the nematode caenorhabditis elegans, gsls function as receptors of the insecticidal cry toxins produced by bacillus thuringiensis (bt), and mutations in bre genes involved in gsls synthesis resulted in resistance to cry5 toxin in this orga ... | 2016 | 27190043 |
| western corn rootworm (coleoptera: chrysomelidae) larval movement in ecry3.1ab+mcry3a seed blend scenarios. | corn fields planted with plant-incorporated bacillus thuringiensis (bt) proteins must have a portion of the field planted with non-bt, isoline, plants that serve as a refuge for susceptible insects. in the corn belt, refuge seeds are now blended in the bag with bt seeds for corn hybrids containing two or more toxins targeted toward the western corn rootworm, diabrotica virgifera virgifera leconte. syngenta's corn hybrid, agrisure duracade, containing the ecry3.1ab (event 5307) and mcry3a (event ... | 2016 | 27190042 |
| genetic transformation and expression of transgenic lines of populus x euramericana with insect-resistance and salt-tolerance genes. | we characterized new transgenic varieties of poplar with multiple insect-resistant and salt stress tolerant genes. two insect-resistant bacillus thuringiensis (bt) genes, cry1ac and cry3a, and a salt-tolerant gene, betaine aldehyde dehydrogenase (badh) were inserted into a vector, p209-cry1ac-cry3a-badh. the clone of populus x euramericana was transformed by the vector using the agrobacterium-mediated method. three transgenic lines were assessed using genetic detection and resistance expression ... | 2016 | 27173305 |
| cloning, expression, purification, and insecticidal activity of a novel cry1na3 toxin from bacillus thuringiensis brc-zyr2. | bacillus thuringiensis produces a variety of insecticidal crystal proteins (icps). genome sequencing is a promising strategy for detecting and identifying b. thuringiensis icps, which are of great interest to the biocontrol field. in this study, a novel icp gene was cloned from b. thuringiensis brc-zyr2 based on genomic data from 454 gs-flx titanium sequencing and an analysis of the results using the b. thuringiensis toxin_scanner (http://bcam.hzaubmb.net/bttoxin_scanner/index.php). cry1na3 desi ... | 2016 | 27170729 |
| marker-free transgenic rice expressing the vegetative insecticidal protein (vip) of bacillus thuringiensis shows broad insecticidal properties. | genetically engineered rice lines with broad insecticidal properties against major lepidopteran pests were generated using a synthetic, truncated form of vegetative insecticidal protein (syn vip3br) from bacillus thuringiensis. the selectable marker gene and the redundant transgene(s) were eliminated through cre/ lox mediated recombination and genetic segregation to make consumer friendly bt -rice. for sustainable resistance against lepidopteran insect pests, chloroplast targeted synthetic versi ... | 2016 | 27165311 |
| evaluation of potential fitness costs associated with ecry3.1ab resistance in diabrotica virgifera virgifera (coleoptera: chrysomelidae). | both an ecry3.1ab-selected and paired control western corn rootworm, diabrotica virgifera virgifera leconte, colony were tested for adult longevity, egg oviposition, egg viability, and larval development in order to evaluate the potential fitness costs associated with ecry3.1ab resistance. adult longevity experiments were conducted by pairing virgin males and females together in plastic boxes supplied with food, water, and ovipositional medium and observed for survival time. eggs were also colle ... | 2016 | 27151470 |
| 4-hydroxyisoleucine: a potential new treatment for type 2 diabetes mellitus. | 4-hydroxyisoleucine (4-hil) is a compound found in trigonella foenum-graecum (fenugreek) seeds, which have been used as part of traditional medicine to treat diabetes mellitus. the synthesis of 4-hil on a large scale is possible using fermentation methods (artificial synthesis) involving the isolation of the l-isoleucine dioxygenase gene from bacillus thuringiensis, which can yield a greater quantity of 4-hil than that produced with conventional methods (82 % attained with fermentation methods v ... | 2016 | 27151154 |
| fitness costs and stability of cry1fa resistance in brazilian populations of spodoptera frugiperda. | the presence of fitness costs of resistance to bacillus thuringiensis (bt) insecticidal proteins in insect populations may delay or even reverse the local selection of insect resistance to bt transgenic crops, and deserves rigorous investigation. here we assessed the fitness costs associated with cry1fa resistance in two strains of fall armyworm, spodoptera frugiperda (lepidoptera: noctuidae), derived from field collections in different brazilian regions and further selected in the laboratory fo ... | 2017 | 27147125 |
| expression of cry1ab gene from a novel bacillus thuringiensis strain sy49-1 active on pest insects. | in this study, the cry1ab gene of previously characterized and lepidoptera-, diptera-, and coleoptera-active bacillus thuringiensis sy49-1 strain was cloned, expressed and individually tested on ephestia kuehniella (lepidoptera: pyralidae) and plodia interpunctella (lepidoptera: pyralidae) larvae. pet-cry1ab plasmids were constructed by ligating the cry1ab into pet28a (+) expression vector. constructed plasmids were transferred to an escherichia coli bl21 (de3) strain rendered competent with cac ... | 2017 | 27143037 |
| adult exposure to bt toxin cry1ac reduces life span and reproduction of resistant and susceptible pink bollworm (lepidoptera: gelechiidae). | insecticidal proteins from bacillus thuringiensis (bt) are used widely in sprays and transgenic plants to control insect pests. although much research has elucidated the effects of bt toxins on larvae, relatively little is known about their effects on adults. here, we evaluated the effects of exposing adults to bt toxin cry1ac on the life span and reproduction of two strains of pink bollworm (pectinophora gossypiella (saunders)). in larval diet bioassays, the concentration of cry1ac killing 50% ... | 2016 | 27133579 |
| a promising hd133-like strain of bacillus thuringiensis with dual efficiency to the two lepidopteran pests: spodoptera littoralis (noctuidae) and ephestia kuehniella (pyralidae). | isolation and identification of new strains with wide variety of target pests is an ever growing field. in this paper, a screening of 260 strains from tunisian soil samples was conducted by dot-blot and pcr-sequencing analysis. the screening was done on the basis of the possession of cry1d-type genes and was followed by the evaluation of the insecticidal activity against spodoptera littoralis. blb250 strain showed an lc50 value (56.2 μg g(-1)) against s. littoralis lower than those of the two ba ... | 2016 | 27130040 |
| does bt maize expressing cry1ac protein have adverse effects on the parasitoid macrocentrus cingulum (hymenoptera: braconidae)? | the potential effects of insect-resistant, genetically engineered (ge) crops on non-target organisms, especially on predators and parasitoids, must be evaluated before their commercial cultivation. the effects of ge maize that produces cry1ac toxin on the parasitoid macrocentrus cingulum were assessed by direct bioassay and indirect bioassay. in the indirect bioassay, parasitism rate, cocoon weight and the number of m. cingulum progeny produced per host were significantly reduced when m. cingulu ... | 2016 | 27126195 |
| field-based assessment of resistance to bt corn by western corn rootworm (coleoptera: chrysomelidae). | western corn rootworm, diabrotica virgifera virgifera leconte, is a serious pest of corn and is managed with corn that produces insecticidal toxins derived from the bacterium bacillus thuringiensis (bt). beginning in 2009, resistance to cry3bb1 corn, and severe injury to cry3bb1 corn in the field, was observed in iowa. however, few data exist on how cry3bb1-resistant western corn rootworm interact with various management practices in the field. using a field experiment, we measured adult emergen ... | 2016 | 27122498 |
| bt toxin cry1ie causes no negative effects on survival, pollen consumption, or olfactory learning in worker honey bees (hymenoptera: apidae). | the honey bee (apis mellifera l.) is a key nontarget insect in environmental risk assessments of insect-resistant genetically modified crops. in controlled laboratory conditions, we evaluated the potential effects of cry1ie toxin on survival, pollen consumption, and olfactory learning of young adult honey bees. we exposed worker bees to syrup containing 20, 200, or 20,000 ng/ml cry1ie toxin, and also exposed some bees to 48 ng/ml imidacloprid as a positive control for exposure to a sublethal con ... | 2016 | 27122497 |
| continuous evolution of bacillus thuringiensis toxins overcomes insect resistance. | the bacillus thuringiensis δ-endotoxins (bt toxins) are widely used insecticidal proteins in engineered crops that provide agricultural, economic, and environmental benefits. the development of insect resistance to bt toxins endangers their long-term effectiveness. here we have developed a phage-assisted continuous evolution selection that rapidly evolves high-affinity protein-protein interactions, and applied this system to evolve variants of the bt toxin cry1ac that bind a cadherin-like recept ... | 2016 | 27120167 |
| frequency of cry1f non-recessive resistance alleles in north carolina field populations of spodoptera frugiperda (lepidoptera: noctuidae). | fall armyworm, spodoptera frugiperda (j.e. smith) (lepidoptera: noctuidae), is a target species of transgenic corn (zea mays l.) that expresses single and pyramided bacillus thuringiensis (bt) toxin. in 2014, s. frugiperda were collected from a light trap in north carolina, and a total of 212 f1/f2 isofemale lines of s. frugiperda were screened for resistance to bt and non-bt corn. all of the 212 isolines were susceptible to corn tissue expressing cry1a.105 + cry2ab, cry1f + cry1a.105 + cry2ab, ... | 2016 | 27119741 |
| experimental evolution in silico: a custom-designed mathematical model for virulence evolution of bacillus thuringiensis. | most mathematical models on the evolution of virulence are based on epidemiological models that assume parasite transmission follows the mass action principle. in experimental evolution, however, mass action is often violated due to controlled infection protocols. this "theory-experiment mismatch" raises the question whether there is a need for new mathematical models to accommodate the particular characteristics of experimental evolution. here, we explore the experimental evolution model system ... | 2016 | 27113405 |
| reproductive isolation between two populations of diatraea saccharalis (f.) (lepidoptera: crambidae) from different host plant species and regions in argentina. | the sugarcane borer, diatraea saccharalis (f.), has a widespread distribution throughout the western hemisphere and is a pest of many crop plants including sugarcane, corn, sorghum and rice. the use of bacillus thuringiensis (bt) corn has been the primary tool for managing this species in corn fields. sugarcane borer control has been recently threatened by observations of susceptibility and/or resistance to certain varieties of bt corn and the protein used in many newer varieties. this has led t ... | 2016 | 27112423 |
| biological activity of bacillus thuringiensis in drosophila suzukii (diptera: drosophilidae). | whole-culture extracts of bacillus thuringiensis berliner strains were assayed against larval and adult drosophila suzukii (matsumura), an important invasive pest of many thin-skinned soft fruit crops in north america. of the 22 serovars tested versus larval d. suzukii, strains of bacillus thuringiensis var. thuringiensis, kurstaki, thompsoni, bolivia, and pakistani caused high (75 to 100%) first-instar mortalities. pupal mortality, measured as a failure of adults to emerge, varied with serovar. ... | 2016 | 27106227 |
| multiple assays indicate varying levels of cross resistance in cry3bb1-selected field populations of the western corn rootworm to mcry3a, ecry3.1ab, and cry34/35ab1. | minnesota populations of diabrotica virgifera virgifera leconte, the western corn rootworm, surviving cry3bb1-expressing corn in the field and western corn rootworm populations assumed to be susceptible to all bt proteins were evaluated for susceptibility to cry3bb1, mcry3a, ecry3.1ab, and cry34/35ab1 in diet assays and three different plant-based assays. rootworm populations originating from cry3bb1 fields and that consistently experienced greater than expected damage had increased survival and ... | 2016 | 27106225 |
| assessment of potential adjuvanticity of cry proteins. | genetically modified (gm) crops have achieved success in the marketplace and their benefits extend beyond the overall increase in harvest yields to include lowered use of insecticides and decreased carbon dioxide emissions. the most widely grown gm crops contain gene/s for targeted insect protection, herbicide tolerance, or both. plant expression of bacillus thuringiensis (bt) crystal (cry) insecticidal proteins have been the primary way to impart insect resistance in gm crops. although deemed s ... | 2016 | 27105772 |
| impact of violated high-dose refuge assumptions on evolution of bt resistance. | transgenic crops expressing bacillus thuringiensis (bt) toxins have been widely and successfully deployed for the control of target pests, while allowing a substantial reduction in insecticide use. the evolution of resistance (a heritable decrease in susceptibility to bt toxins) can pose a threat to sustained control of target pests, but a high-dose refuge (hdr) management strategy has been key to delaying countervailing evolution of bt resistance. the hdr strategy relies on the mating frequency ... | 2016 | 27099624 |
| application of a dense genetic map for assessment of genomic responses to selection and inbreeding in heliothis virescens. | adaptation of pest species to laboratory conditions and selection for resistance to toxins in the laboratory are expected to cause inbreeding and genetic bottlenecks that reduce genetic variation. heliothis virescens, a major cotton pest, has been colonized in the laboratory many times, and a few laboratory colonies have been selected for bacillus thuringiensis (bt) resistance. we developed 350-bp double-digest restriction-site associated dna-sequencing (ddrad-seq) molecular markers to examine a ... | 2016 | 27097739 |
| characterization of the resistance to vip3aa in helicoverpa armigera from australia and the role of midgut processing and receptor binding. | crops expressing genes from bacillus thuringiensis (bt crops) are among the most successful technologies developed for the control of pests but the evolution of resistance to them remains a challenge. insect resistant cotton and maize expressing the bt vip3aa protein were recently commercialized, though not yet in australia. we found that, although relatively high, the frequency of alleles for resistance to vip3aa in field populations of h. armigera in australia did not increase over the past fo ... | 2016 | 27095284 |
| use of redundant exclusion pcr to identify a novel bacillus thuringiensis cry8 toxin gene from pooled genomic dna. | with the aim of optimizing the cloning of novel genes from a genomic pool containing many previously identified homologous genes, we designed a redundant exclusion pcr (re-pcr) technique. in re-pcr, a pair of generic amplification primers are combined with additional primers that are designed to specifically bind to redundant, unwanted genes that are a subset of those copied by the amplification primers. during re-pcr, the specific primer blocks amplification of the full-length redundant gene. u ... | 2016 | 27084017 |
| contrasting invertebrate immune defense behaviors caused by a single gene, the caenorhabditis elegans neuropeptide receptor gene npr-1. | the invertebrate immune system comprises physiological mechanisms, physical barriers and also behavioral responses. it is generally related to the vertebrate innate immune system and widely believed to provide nonspecific defense against pathogens, whereby the response to different pathogen types is usually mediated by distinct signalling cascades. recent work suggests that invertebrate immune defense can be more specific at least at the phenotypic level. the underlying genetic mechanisms are as ... | 2016 | 27066825 |
| heritability of wing size and shape of the rice and corn strains of spodoptera frugiperda (j.e. smith) (lepidoptera: noctuidae). | spodoptera frugiperda (j.e. smith) (lepidoptera: noctuidae) represents a pest of economic importance in all western hemisphere. this polyphagous species has diverged into two populations that have been mainly recognized with various mitochondrial and nuclear molecular markers and named "the rice" and "the corn" strains. in colombia, both strains have evolved prezygotic and postzygotic isolation. they differ in tolerance to bacillus thuringiensis (cry1ac and cry1ab endotoxins) and the insecticide ... | 2016 | 27044394 |
| effects of illuminance and nutrients on bacterial photo-physiology of hydrocarbon degradation. | bacterial photophysiology was previously limited to photoautotrophs. the discovery of bacteriophytochromes in non-photoautotrophs raised a question whether these non-photoautotrophs are affected by the presence or absence of light? in this research work for the first time, bacterial hydrocarbon degradation and biomass production was studied under the influence of nutrients, illuminance (light flux) and time. an experimental model was designed, with six isolated bacterial strains (pseudomonas poa ... | 2016 | 27039061 |
| heme sensing in bacillus thuringiensis: a supplementary hssrs-regulated heme resistance system. | several gram-positive pathogens scavenge host-derived heme to satisfy their nutritional iron requirement. however, heme is a toxic molecule capable of damaging the bacterial cell. gram-positive pathogens within the phylum firmicutes overcome heme toxicity by sensing heme through hssrs, a two-component system that regulates the heme detoxification transporter hrtab. here we show that heme sensing by hssrs and heme detoxification by hrtab occur in the insect pathogen bacillus thuringiensis we find ... | 2016 | 27030728 |
| immuno-physiological adaptations confer wax moth galleria mellonella resistance to bacillus thuringiensis. | microevolutionary mechanisms of resistance to a bacterial pathogen were explored in a population of the greater wax moth, galleria mellonella, selected for an 8.8-fold increased resistance against the entomopathogenic bacterium bacillus thuringiensis (bt) compared with a non-selected (suspectible) line. defense strategies of the resistant and susceptible insect lines were compared to uncover mechanisms underpinning resistance, and the possible cost of those survival strategies. in the uninfected ... | 2016 | 27029421 |
| a role for weak electrostatic interactions in peripheral membrane protein binding. | bacillus thuringiensis phosphatidylinositol-specific phospholipase c (btpi-plc) is a secreted virulence factor that binds specifically to phosphatidylcholine (pc) bilayers containing negatively charged phospholipids. btpi-plc carries a negative net charge and its interfacial binding site has no obvious cluster of basic residues. continuum electrostatic calculations show that, as expected, nonspecific electrostatic interactions between btpi-plc and membranes vary as a function of the fraction of ... | 2016 | 27028646 |
| transcriptional profiling analysis of spodoptera litura larvae challenged with vip3aa toxin and possible involvement of trypsin in the toxin activation. | vip proteins, a new group of insecticidal toxins produced by bacillus thuringiensis, are effective against specific pests including spodoptera litura. here, we report construction of a transcriptome database of s. litura by de novo assembly along with detection of the transcriptional response of s. litura larvae to vip3aa toxin. in total, 56,498 unigenes with an n50 value of 1,853 bp were obtained. results of transcriptome abundance showed that vip3aa toxin provoked a wide transcriptional respon ... | 2016 | 27025647 |
| a mixture of bacillus thuringiensis subsp. israelensis with xenorhabdus nematophila-cultured broth enhances toxicity against mosquitoes aedes albopictus and culex pipiens pallens (diptera: culicidae). | xenorhabdusandphotorhabdusspp. (enterobacteriaceae) can synthesize and release secondary metabolites that play crucial roles in their pathogenicity by suppressing the immunity of target insects. the insect immunity contributes to defense against the pathogenicity ofbacillus thuringiensis(bt). this study tested a hypothesis that bacterial immunosuppresants could enhance the susceptibility of mosquitoes (aedes albopictusandculex pipiens pallens) to bt. three symbiotic bacteria [x. nematophila(xn), ... | 2016 | 27018440 |
| ipm use with the deployment of a non-high dose bt pyramid and mitigation of resistance for western corn rootworm (diabrotica virgifera virgifera). | recent detection of western corn rootworm resistance to bt (bacillus thuringiensis) corn prompted recommendations for the use of integrated pest management (ipm) with planting refuges to prolong the durability of bt technologies. we conducted a simulation experiment exploring the effectiveness of various ipm tools at extending durability of pyramided bt traits. results indicate that some ipm practices have greater merits than others. crop rotation was the most effective strategy, followed by inc ... | 2016 | 27018423 |
| a black (white) hole in the global spread of gm cotton. | bt (bacillus thuringiensis) cotton has been widely adopted, notably by smallholder farmers in developing countries. however, it has not been used in central asia, an important cotton-producing region. we discuss possible reasons and hypothesize that the most likely explanation is limited local demand for bt owing to low levels of pest infestation. this would imply that global bt cotton adoption rates may already be close to 100% when considering real demand for insect-resistant varieties. | 2016 | 27017312 |
| transgenic rice expressing the cry2ax1 gene confers resistance to multiple lepidopteran pests. | a chimeric bacillus thuringiensis toxin (bt) gene, cry2ax1was cloned in a bi-selectable marker free binary vector construct. the cry2ax1 gene, driven by the chrysanthemum rbcs1 promoter, was introduced into jk1044r, the restorer line (oryza sativa l. ssp. indica) of a notified commercially grown rice hybrid in india, by agrobacterium-mediated transformation. its effect against two major lepidopteran insect pests viz., yellow stem borer (ysb) scirpophaga incertulas, rice leaf folder (rlf) cnaphal ... | 2016 | 27017220 |
| ingestion of bt corn pollen containing cry1ab/2aj or cry1ac does not harm propylea japonica larvae. | propylea japonica (thunberg) (coleoptera: coccinellidae) is a prevalent pollen consumer in corn fields and is therefore exposed to insecticidal proteins contained in the pollen of insect-resistant transgenic corn cultivars expressing cry proteins derived from bacillus thuringiensis (bt). in the present study, the potential effect of cry1ab/2aj- or cry1ac-containing transgenic bt corn pollen on the fitness of p. japonica larvae was evaluated. the results show that the larval developmental time wa ... | 2016 | 27005950 |
| a novel metalloproteinase virulence factor is involved in bacillus thuringiensis pathogenesis in nematodes and insects. | the gram-positive soil bacterium bacillus thuringiensis has been developed as the leading microbial insecticide for years. the pathogenesis of b. thuringiensis requires common extracellular factors that depend on the plcr regulon, which regulates a large number of virulence factors; however, the precise role of many of these proteins is not known. in this study, we describe the complete lifecycle of a nematicidal b. thuringiensis strain in the free living nematode caenorhabditis elegans using in ... | 2016 | 26995589 |
| comparison of susceptibility of chilo suppressalis and bombyx mori to five bacillus thuringiensis proteins. | transformation of rice with genes encoding insecticidal cry proteins from bacillus thuringiensis (bt) should confer high resistance to target lepidopteran pests, such as chilo suppressalis, and low toxicity to non-target organisms, such as silkworm bombyx mori. five purified cry proteins that have been used for plant transformation were tested using dietary exposure assays. the susceptibility of c. suppressalis larvae to the five insecticidal proteins in the decreasing order was: cry1ca>cry1ab>c ... | 2016 | 26994840 |
| daphnia magna negatively affected by chronic exposure to purified cry-toxins. | cry-toxin genes originating from bacillus thuringiensis are inserted into genetically modified (gm) plants, often called bt-plants, to provide insect resistance to pests. significant amounts of bt-plant residues, and thus cry-toxins, will be shed to soil and aquatic environments. we exposed daphnia magna to purified cry1ab and cry2aa toxins for the full life-span of the animals. we used single toxins in different doses and combinations of toxins and roundup(®), another potential stressor on the ... | 2016 | 26993955 |