| determination of binding of bacillus thuringiensis (delta)-endotoxin receptors to rice stem borer midguts. | insecticidal activity and receptor binding properties of bacillus thuringiensis toxins to yellow and striped rice stem borers (sciropophaga incertulas and chilo suppresalis, respectively) were investigated. yellow stem borer (ysb) was susceptible to cry1aa, cry1ac, cry2a, and cry1c toxins with similar toxicities. to striped stem borer (ssb), cry1ac, cry2a, and cry1c were more toxic than cry1aa toxin. binding assays were performed with (sup125)i-labeled toxins (cry1aa, cry1ac, cry2a, and cry1c) a ... | 1997 | 16535573 |
| a change in a single midgut receptor in the diamondback moth (plutella xylostella) is only in part responsible for field resistance to bacillus thuringiensis subsp. kurstaki and b. thuringiensis subsp. aizawai. | a population (serd3) of the diamondback moth (plutella xylostella l.) with field-evolved resistance to bacillus thuringiensis subsp. kurstaki hd-1 (dipel) and b. thuringiensis subsp. aizawai (florbac) was collected. laboratory-based selection of two subpopulations of serd3 with b. thuringiensis subsp. kurstaki (btk-sel) or b. thuringiensis subsp. aizawai (bta-sel) increased resistance to the selecting agent with little apparent cross-resistance. this result suggested the presence of independent ... | 1997 | 16535597 |
| inheritance of resistance to the bacillus thuringiensis toxin cry1c in the diamondback moth. | laboratory selection increased resistance to the bacillus thuringiensis toxin cry1c in a strain of diamondback moth (plutella xylostella). the selected strain was derived from a field population that had evolved high levels of resistance to bacillus thuringiensis subsp. kurstaki and moderate resistance to cry1c. relative to the responses of a susceptible strain of diamondback moth, the resistance to cry1c of the selected strain increased to 62-fold after six generations of selection. the realize ... | 1997 | 16535623 |
| microbial utilization of free and clay-bound insecticidal toxins from bacillus thuringiensis and their retention of insecticidal activity after incubation with microbes. | the insecticidal toxins produced by bacillus thuringiensis subspp. kurstaki and tenebrionis were resistant when bound on clays, but not when free, to utilization by pure and mixed cultures of microbes as sources of carbon and carbon plus nitrogen, and their availability as a nitrogen source was reduced. the bound toxins retained insecticidal activity both before and after exposure to microbes or pronase. the insecticidal activity of the toxins persisted for 40 days (the longest time evaluated) i ... | 1997 | 16535692 |
| cry9ca1 toxin, a bacillus thuringiensis insecticidal crystal protein with high activity against the spruce budworm (choristoneura fumiferana). | the cry9ca1 toxin from bacillus thuringiensis was significantly more toxic to spruce budworm (choristoneura fumiferana) than the cry1ab6, cry1ba1, cry1ca2, cry1da1, cry1ea1, and cry1fa2 toxins. it displayed high activity against silkworm (bombyx mori) but was not toxic to black army cutworm (actebia fennica) or gypsy moth (lymantria dispar). the cry9ca1 is the most effective spruce budworm toxin known to date and may offer promise for control and resistance management of that species. | 1997 | 16535721 |
| evolution of resistance to transgenic crops: interactions between insect movement and field distribution. | the refuge strategy is designed to delay evolution of pest resistance to transgenic crops producing bacillus thuringiensis berliner (bt) toxins. movement of insects between bt crops and refuges of non-bt crops is essential for the refuge strategy because it increases chances that resistant adults mate with susceptible adults from refuges. conclusions about optimal levels of movement for delaying resistance are not consistent among previous modeling studies. to clarify the effects of movement on ... | 2005 | 16539091 |
| efficacy of bacillus thuringiensis against phyllocnistis citrella (lepidoptera: phyllocnistidae). | the purpose of this work was to analyze the efficacy of bacillus thuringiensis berliner on the control of phyllocnistis citrella stainton (lepidoptera: phyllocnistidae) in laboratory and field trials. in the laboratory, four b. thuringiensis were used: dipel (commercial formulation) tested at the concentrations of 25 x 10(6) and 25 x 10(8) spores/ml and the isolates k, 6, and 15 (collections of the university of azores) at the concentration of 25 x 10(6) spores/ ml. a surfactant solution of nono ... | 2005 | 16539108 |
| starch industry wastewater-based stable bacillus thuringiensis liquid formulations. | liquid formulations were developed from bacillus thuringiensis (bt)-fermented broths of starch industry wastewater (siw) and of soya medium. stability studies were carried out for 1 yr. storage stability was tested by studying various physical and chemical (e.g., viscosity, particle size, corrosion, and suspendibility) and biological (e.g., microbial contamination, viable spores, and entomotoxicity) parameters at different ph levels and temperatures. three suspending agents, sorbitol, sodium mon ... | 2005 | 16539110 |
| abundance of coleomegilla maculata (coleoptera: coccinellidae) in corn rootworm-resistant cry3bb1 maize. | lady beetles (coleoptera: coccinellidae) are important polyphagous predators in maize, zea mays l., fields. transgenic cry3bb1 maize hybrids express a coleopteran-specific insecticidal protein derived from bacillus thuringiensis (berliner) subsp. kumamotoensis that is targeted at corn rootworm larvae. this study evaluated impacts of cry3bb1 protein-expressing maize, tefluthrin-treated maize, and untreated controls on lady beetle abundance at preanthesis, anthesis, and postanthesis maize-developm ... | 2005 | 16539124 |
| evaluation of a chemically inducible promoter for developing a within-plant refuge for resistance management. | chemically inducible production of bacillus thuringiensis (bt) toxins in transgenic plants may provide considerable benefits in preventing or delaying the evolution of insect resistance to bt crops by creating within-plant temporal refuges. we examined the effect of inducible cry1ab expression on survival of different genotypes (rr, rs, and ss) of diamondback moth, plutella xylostella (l.), in transgenic broccoli, brassica oleracea l., plants transformed with a pr-1a/cry1ab expression cassette. ... | 2005 | 16539150 |
| effect of extended diapause on evolution of resistance to transgenic bacillus thuringiensis corn by northern corn rootworm (coleoptera: chrysomelidae). | we develop a population genetics model for the northern corn rootworm, diabrotica barberi smith & lawrence, to examine the effect of extended diapause on the evolution of resistance to transgenic bacillus thuringiensis (bt) corn, zea mays l. we model conditions found in the center of the extended diapause problem along the minnesota-south dakota-iowa borders. the proportion of resistance alleles in eggs oviposited after 15 simulated years is used to measure the evolution of resistance. sensitivi ... | 2005 | 16539154 |
| diversity of commensal bacillus cereus sensu lato isolated from the common sow bug (porcellio scaber, isopoda). | although bacillus cereus sensu lato are important both from an ecological and an economical point of view, little is known about their population structure, ecology, and relationships with other organisms. in the present work, the genotypic similarity of arthropod-borne b. cereus s.l. isolates, and their symbiotic relationship with the host are assessed. bacilli of this group were recovered from the digestive tracts of sow bugs (porcellio scaber) collected in three closely located sites. their g ... | 2006 | 16542411 |
| novel technology for rapid species-specific detection of bacillus spores. | there is an urgent need for a small, inexpensive sensor that can rapidly detect bio-warfare agents with high specificity. bacillus anthracis, the causative agent of anthrax, would be a perilous disease-causing organism in the event of a release. currently, most anthrax detection research is based on nucleic acid detection, immunoassays and mass spectrometry, with few detection levels reported below 10(5) spores. here, we show the ability to distinguish bacillus spores to a level approaching 10(3 ... | 2006 | 16542873 |
| detection of bacillus thuringiensis kurstaki hd1 on cabbage for human consumption. | the objectives of the study were to develop a specific procedure for quantification and identification of bacillus thuringiensis kurstaki hd1, which is used as a biopesticide, and to quantify its presence in different kinds of cabbage for human consumption. we found that b. thuringiensis kurstaki hd1 can be distinguished from other b. thuringiensis strains by its unique random amplification of polymophic dna-pcr pattern with the opa9 primer and the presence of the flagellin genes, as detected by ... | 2006 | 16553839 |
| physiology of sporeforming bacteria associated with insects ii. lipids of vegetative cells. | lipid composition was studied in two strains each of mid-log phase cells of bacillus thuringiensis, b. larvae, b. popilliae, b. alvei, and b. lentimorbus. total lipids varied from 2.5 to 3.5% of the cell dry weight of b. thuringiensis to 4.3 to 5.0% of b. popilliae. phospholipids in the organisms examined ranged from 55 to 79% of total lipids; neutral lipids averaged from 13 to 45%. common phospholipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, and lysophosphat ... | 1970 | 16559100 |
| engineered bacillus thuringiensis go33a with broad insecticidal activity against lepidopteran and coleopteran pests. | a recombinant plasmid pstk-3a containing cry3aa7 gene encoding a coleopteran-specific insecticidal protein was constructed and introduced into wild bacillus thuringiensis subsp. aizawai g03, which contained cry1aa, cry1ac, cry1ca, and cry2ab genes and was highly toxic to lepidopteran insect pests. the genetically engineered strain were named g033a. sodium dodecyl sulfate-polyacrylamide gel electrophoresis and western blot analysis demonstrated that the cry3aa7 gene was expressed normally and pro ... | 2006 | 16572346 |
| management of cottonwood leaf beetle (coleoptera: chrysomelidae) with a novel transplant soak and biorational insecticides to conserve coccinellid beetles. | biorational foliar sprays and a novel application method of soaking transplants in imidacloprid were evaluated for control of adult and larval cottonwood leaf beetle, chrysomela scripta f., on hybrid poplar, with emphasis on conservation of coccinellid predators. foliar sprays of four biorational insecticides killed adult and larval c. scripta: bacillus thuringiensis (b.t.) variety tenebrionis (novodor), b.t. variety kurstaki (raven), spinosad (conserve sc), and azadirachtin (azatin xl) (larvae ... | 2006 | 16573329 |
| susceptibilities of helicoverpa zea and heliothis virescens (lepidoptera: noctuidae) populations to cry1ac insecticidal protein. | susceptibilities of bollworm, helicoverpa zea (boddie) and tobacco budworm, heliothis virescens (f.) to cry1ac were measured via a diet-incorporated assay with mpv ii at the university of arkansas during 2002-2004. lethal concentration-mortality (lc50) estimates of five laboratory, seven laboratory-cross, and 10 field populations of h. virescens varied 12-fold. pooled susceptibilities of h. virescens across all laboratory and field populations varied five-fold. the lc50 estimates for h. virescen ... | 2006 | 16573337 |
| comparative susceptibility of european corn borer, southwestern corn borer, and sugarcane borer (lepidoptera: crambidae) to cry1ab protein in a commercial bacillus thuringiensis corn hybrid. | one field strain each of the european corn borer, ostrinia nubilalis (hübner); southwestern corn borer, diatraea grandiosella dyar; and sugarcane borer, diatraea saccharalis (f.); were collected from cornfields in northeastern louisiana. susceptibilities of the field strain and a corresponding laboratory strain of the three borer species to cry1ab protein in dk69-70 bacillus thuringiensis (bt) corn hybrid were determined by exposing neonates to intact leaf tissues from whorl stage plants or by f ... | 2006 | 16573340 |
| do herbicide treatments reduce the sensitivity of mosquito larvae to insecticides? | invasive mosquitoes are economic and sanitary concerns especially in europe and america. most work has emphasized the role of resistance [berrada, s., fournier, d., cuany, a., nguyen, t.x., 1994. identification of resistance mechanisms in a selected laboratory strain of cacopsylla pyri (homoptera: psyllidae): altered acetylcholinesterases and detoxifying oxidases. pesticide biochemistry and physiology 48, 41-47; hemingway, j., hawkes, n.j., mccarroll, l., ranson, h., 2004. the molecular basis of ... | 2006 | 16574189 |
| [effects of helper protein p20 from bacillus thuringiensis on vip3a expression]. | insecticidal crystal proteins (icps) produced in bacillus thuringiensis accumulate as crystalline inclusions that represent up to 30% of total dry weight the cell produces. the mechanisms of in vivo crystallization of these insecticidal proteins remain interests, yet unclear. a 20-kda protein (p20), the product of the third open reading frame of cry11a operon in b. thuringiensis subsp. israelensis has been defined to be an important molecular chaperone (helper protein) for forming cyt1a crystal ... | 2006 | 16579471 |
| molecular cloning and characterization of the insecticidal crystal protein gene of bacillus thuringiensis var. tenebrionis. | the insecticidal crystal protein gene of the coleopteran-toxic bacillus thuringiensis var. tenebrionis has been isolated, and the nucleotide sequence has been determined. a total dna library from var. tenebrionis was made in the plasmid vector puc12. by using a synthetic 27-base oligonucleotide corresponding to a stretch of nine n-terminal amino acids of a tryptic fragment of purified crystal protein of var. tenebrionis as a probe, recombinant colonies were screened by in situ hybridization for ... | 1987 | 16593878 |
| assessing the effects of bt maize on the predatory mite neoseiulus cucumeris. | the investigation of neoseiulus cucumeris in the context of the ecological risk assessment of insect resistant transgenic plants is of particular interest as this omnivorous predatory mite species is commercially available and considered important for biological control. in a multitrophic feeding experiment we assessed the impact of bt maize on the performance of n. cucumeris when offered spider mites (tetranychus urticae) reared on bt (bt11, syngenta) or non-bt maize (near isogenic line) and bt ... | 2006 | 16596347 |
| differential effects of ionic strength, divalent cations and ph on the pore-forming activity of bacillus thuringiensis insecticidal toxins. | the combined effects of ionic strength, divalent cations, ph and toxin concentration on the pore-forming activity of cry1ac and cry1ca were studied using membrane potential measurements in isolated midguts of manduca sexta and a brush border membrane vesicle osmotic swelling assay. the effects of ionic strength and divalent cations were more pronounced at ph 10.5 than at ph 7.5. at the higher ph, lowering ionic strength in isolated midguts enhanced cry1ac activity but decreased considerably that ... | 2005 | 16596448 |
| some bacillus thuringiensis strains share rpob nucleotide polymorphisms also present in bacillus anthracis. | | 2006 | 16597912 |
| toxicity and mode of action of bacillus thuringiensis cry proteins in the mediterranean corn borer, sesamia nonagrioides (lefebvre). | sesamia nonagrioides is one of the most damaging pests of corn in spain and other mediterranean countries. bt corn expressing the bacillus thuringiensis cry1ab toxin is being grown on about 58,000 ha in spain. here we studied the mode of action of this cry protein on s. nonagrioides (binding to specific receptors, stability of binding, and pore formation) and the modes of action of other cry proteins that were found to be active in this work (cry1ac, cry1ca, and cry1fa). binding assays were perf ... | 2006 | 16597962 |
| bacillus thuringiensis and bacillus sphaericus biopesticides production. | the long residual action and toxicity of the chemical insecticides have brought about serious environmental problems such as the emergence and spread of insecticide resistance in many species of vectors, mammalian toxicity, and accumulation of pesticide residues in the food chain. all these problems have highlighted the need for alternative biological control agents. entomo-pathogenic bacillus thuringiensis (bt) and bacillus sphaericus (bs) are two safe biological control agents. they have attra ... | 2006 | 16598830 |
| evaluation of the present dengue situation and control strategies against aedes aegypti in cebu city, philippines. | the present dengue situation and methods to control aedes aegypti larvae in cebu city, philippines, were evaluated for the development of an integrated community-based dengue control program. the study included the detection of dengue infection among filipino patients, surveying mosquito breeding sites to determine larval population density of aedes aegypti, an evaluation of public knowledge, attitude, and personal protection practices against dengue, and an evaluation of the efficacy of vectoba ... | 2005 | 16599163 |
| differentiated pattern of protein composition of crystalline inclusions of newly isolated bacillus thuringiensis strains from silesia in poland. | protein profiles of crystal delta-endotoxins were determined in twenty nine bacillus thuringiensis strains-soil and phylloplane isolates--from poland. electrophoretic analysis revealed quantatively and qualitatively different patterns of delta-endotoxin crystal preparations of these b. thuringiensis strains. the crystalline parasporal inclusions of b. thuringiensis isolates were composed of two, three, four or five proteins. molecular weights of these polypeptides varied from 23.4 kda to 142 kda ... | 2005 | 16599296 |
| functional display of bacillus thuringiensis cry1ac toxin on t7 phage. | the cry1ac toxin from bacillus thuringiensis was displayed on the surface of t7 phage. the cry1ac gene was fused to the c-terminal end of t7-10b capsid protein and displayed on the surface of t7 phage as revealed by western blot analysis of the purified phage particles. the t7-cry1ac phages retained toxicity against manduca sexta larvae. we demonstrated that the t7-cry1ac phage interacts with cry1ac receptors present in m. sexta bbmv either in solution or in overlay binding assays. | 2006 | 16603180 |
| co-expression of alpha(1,3)galactosyltransferase and bacillus thuringiensis piplc enhances hyperacute rejection of tumor cells. | the use of alpha(1,3)galactosyltransferase (alphagt) as a method of inducing hyperacute rejection of tumors has been gaining interest recently. however, the approach is based in part on the sensitivity of each tumor line to the effects of complement lysis. tumors expressing complement resistance factors such as membrane cofactor (cd46), decay accelerating factor (cd55) and protectin (cd59) have been shown to be more resistant to complement mediated lysis. anchored to the membrane by a glycosylph ... | 2007 | 16612594 |
| improvement of bacillus thuringiensis delta-endotoxins synthesis yields through acquisition of erythromycin resistance. | the acquisition of the erythromycin resistance by bacillus thuringiensis kurstaki improved yields of delta-endotoxins in sporulating cells ranging from 134 to 215%. resistance to erythromycin decreased the final spore count by at least 50%. consequently, erythromycin resistance is an efficient tool for the improvement of bioinsecticides yields with a high ratio of delta-endotoxins to spores. | 2006 | 16614918 |
| bacillus thuringiensis insecticidal cry1ab toxin does not affect the membrane integrity of the mammalian intestinal epithelial cells: an in vitro study. | the mammalian intestinal epithelium has been found, based on in vivo experiments, to be resistant to insecticidal cry toxins, which are derived from bacillus thuringiensis and fatally damage insect midgut cells. thus, the toxins are commonly used as a genetic resource in insect-resistant transgenic plants for feed. however, cry toxins bind to the cellular brush border membrane vesicle (bbmv) of mammalian intestinal cells. in this study, we investigated the affinity of cry1ab toxin, a lepidoptera ... | 2006 | 16618212 |
| pathogenomic sequence analysis of bacillus cereus and bacillus thuringiensis isolates closely related to bacillus anthracis. | bacillus anthracis, bacillus cereus, and bacillus thuringiensis are closely related gram-positive, spore-forming bacteria of the b. cereus sensu lato group. while independently derived strains of b. anthracis reveal conspicuous sequence homogeneity, environmental isolates of b. cereus and b. thuringiensis exhibit extensive genetic diversity. here we report the sequencing and comparative analysis of the genomes of two members of the b. cereus group, b. thuringiensis 97-27 subsp. konkukian serotyp ... | 2006 | 16621833 |
| structure of the functional form of the mosquito larvicidal cry4aa toxin from bacillus thuringiensis at a 2.8-angstrom resolution. | the cry4aa delta-endotoxin from bacillus thuringiensis is toxic to larvae of culex, anopheles, and aedes mosquitoes, which are vectors of important human tropical diseases. with the objective of designing modified toxins with improved potency that could be used as biopesticides, we determined the structure of this toxin in its functional form at a resolution of 2.8 angstroms. like other cry delta-endotoxins, the activated cry4aa toxin consists of three globular domains, a seven-alpha-helix bundl ... | 2006 | 16621834 |
| cyt2ba of bacillus thuringiensis israelensis: activation by putative endogenous protease. | the gene cyt2ba of bacillus thuringiensis subsp. israelensis was cloned for expression, together with p20, in an acrystalliferous strain. the large hexagonal crystals formed were composed of cyt2ba, which facilitated its purification. crystal solubilization in the presence of endogenous proteases (with spores and cell debris) enabled quick and simple procedure to obtain rather pure and active toxin species by cleavage between amino acid residues 34 and 35, most likely by a camelysin-like proteas ... | 2006 | 16630537 |
| cloning, characterization, and expression of a new cry2ab gene from bacillus thuringiensis strain 14-1. | bacillus thuringiensis is the major source for transfer of genes to impart insect resistance in transgenic plants. cry2a proteins of b. thuringiensis are promising candidates for management of resistance development in insects owing to their difference from the currently used cry1a proteins, in structure and insecticidal mechanism. the cry2ab gene was found to lack a functional promoter and, hence, is cryptic in nature. the cry2ab7 gene was cloned from a new indigenous b. thuringiensis strain, 1 ... | 2006 | 16632879 |
| carboxy-terminal extension effects on crystal formation and insecticidal properties of colorado potato beetle-active bacillus thuringiensis delta-endotoxins. | many bacillus thuringiensis crystal proteins, particularly those active against lepidopteran insects, have carboxy-terminal extensions that mediate bipyramidal crystal formation. these crystals are only soluble at high (>10.0) ph in reducing conditions such as generally found in the lepidopteran midgut. most of the colorado potato beetle (cpb)-active toxins lack such an extension, yet some toxins with a carboxy-terminal extension have cryptic activity against this insect, revealed only after in ... | 2006 | 16632885 |
| simple and rapid method for detection of bacterial spores in powder useful for first responders. | the need for a rapid method by which first responders can screen for the presence of spores in powder samples has been increased since the anthrax attack of 2001. the majority of powders that were sampled in the context of that attack were hoaxes and did not contain bacillus anthracis. the large number of samples overwhelmed the analysis capacity of public health laboratories. a rapid screening method for determining the presence of viable spores would eliminate much laboratory work and expedite ... | 2006 | 16637561 |
| relationship between poly-beta-hydroxybutyrate production and delta-endotoxin for bacillus thuringiensis var. kurstaki. | a linear relationship between total solid concentration (tsc), delta-endotoxin production [cry = 0.2795(tsc)-0.2472, r2 = 0.8644] and poly-beta-hydroxybutyrate (phb) accumulation [phb = 0.1327(tsc) + 0.3974, r2 = 0.9877] in bacillus thuringiensis var. kurstaki hd-73 was observed. a similar correlation between delta-endotoxin and phb accumulation [cry = 2.1573(phb)-1.1248, r2 = 0.9181] was found. a minimum phb accumulation of 0.52 mg l(-1) was required before the onset of delta-endotoxin producti ... | 2006 | 16642302 |
| discovery of a significant optical chromatographic difference between spores of bacillus anthracis and its close relative, bacillus thuringiensis. | a significant difference between two closely related bacillus spores has been discovered using optical chromatography. this difference can be harnessed for the separation of microscopic particles using opposing laser and fluid flow forces. particles of different size, composition, and shape experience different optical and fluid forces and come to rest at unique equilibrium positions where the two forces balance. separations in excess of 600 mum have been observed between bacillus anthracis ster ... | 2006 | 16643018 |
| susceptibility of laboratory and field-collected aedes aegypti and aedes albopictus to bacillus thuringiensis israelensis h-14. | susceptibility levels of a few laboratory-cultured and dengue-endemic area field-collected strains of aedes aegypti and aedes albopictus to bacillus thuringiensis israelensis (bti) at different storage ages were studied. the susceptibility of laboratory-cultured world health organization (who) bora bora reference, vector control research unit (vcru), and fumakilla malaysia berhad (fmb) strains of ae. aegypti to bti was examined. the sensitivity to bti decreased with storage age. the median letha ... | 2006 | 16646329 |
| mitigating the effects of the green alga scenedesmus quadricauda on the efficacy of bacillus thuringiensis var. israelensis against larval black flies. | the green alga scenedesmus quadricauda has been shown to decrease the efficacy of bacillus thuringiensis var. israelensis (bti) to black fly larvae in laboratory experiments. in this study, 2 approaches to mitigating the effects of s. quadricauda were tested, increasing the dose of bti exposed to the larval black flies and increasing the length of the exposure period. results showed that increasing the dose as well as increasing the exposure time were effective methods for mitigating the effects ... | 2006 | 16646337 |
| susceptibility of adult coccinella septempunctata (coleoptera: coccinellidae) to insecticides with different modes of action. | five insecticides (pyriproxifen, imidacloprid, deltamethrin + heptenophos, lambda-cyhalothrin and bacillus thuringiensis berliner subsp. tenebrionis) were examined in the laboratory for their acute detrimental side-effects at field rates on adult seven-spot ladybird beetle, coccinella septempunctata l. the toxicity of the preparations was determined by measuring the acute surface contact effects (dried spray on leaves of philadelphus coronarius l.), except for b. thuringiensis where mixed pollen ... | 2006 | 16649191 |
| bacillus thuringiensis section sign-endotoxin expressed in transgenic nicotiana tabacum provides resistance to lepidopteran insects. | the crystal proteins, or section sign-endotoxins, of bacillus thuringiensis are specifically lethal to lepidopteran insects. we utilized a truncated and modified portion of a cloned crystal protein gene to construct a chimeric gene capable of expression in plant cells. using an agrobacterium tumefaciens binary vector system, we then transferred the chimeric toxin gene into tobacco (nicotiana tabacum cv havana 425) cells and regenerated recombinant plants. one to several copies per cell of the to ... | 1987 | 16665812 |
| occurrence of natural bacillus thuringiensis contaminants and residues of bacillus thuringiensis-based insecticides on fresh fruits and vegetables. | a total of 128 bacillus cereus-like strains isolated from fresh fruits and vegetables for sale in retail shops in denmark were characterized. of these strains, 39% (50/128) were classified as bacillus thuringiensis on the basis of their content of cry genes determined by pcr or crystal proteins visualized by microscopy. random amplified polymorphic dna analysis and plasmid profiling indicated that 23 of the 50 b. thuringiensis strains were of the same subtype as b. thuringiensis strains used as ... | 2006 | 16672488 |
| the international bacillus anthracis, b. cereus, and b. thuringiensis conference, "bacillus-act05". | | 2006 | 16672596 |
| farm-scale evaluation of the impacts of transgenic cotton on biodiversity, pesticide use, and yield. | higher yields and reduced pesticide impacts are needed to mitigate the effects of agricultural intensification. a 2-year farm-scale evaluation of 81 commercial fields in arizona show that use of transgenic bacillus thuringiensis (bt) cotton reduced insecticide use, whereas transgenic cotton with bt protein and herbicide resistance (bthr) did not affect herbicide use. transgenic cotton had higher yield than nontransgenic cotton for any given number of insecticide applications. however, nontransge ... | 2006 | 16675554 |
| inactivation of biological agents using neutral oxone-chloride solutions. | bleach solutions containing the active ingredient hypochlorite (ocl-) serve as powerful biological disinfectants but are highly caustic and present a significant compatibility issue when applied to contaminated equipment or terrain. a neutral, bicarbonate-buffered aqueous solution of oxone (2k2hso5.khso4.k2so4) and sodium chloride that rapidly generates hypochlorite and hypochlorous acid (hocl) in situ was evaluated as a new alternative to bleach for the inactivation of biological agents. the so ... | 2006 | 16683620 |
| inheritance of resistance to the cry1ab bacillus thuringiensis toxin in ostrinia nubilalis (lepidoptera: crambidae). | laboratory selection with cry1ab, the predominant bacillus thuringiensis (bt) toxin in transgenic corn, zea mays l., produced >1000-fold resistance in two laboratory strains of european corn borer, ostrinia nubilalis (hübner). we tested the offspring of various crosses to determine the mode of inheritance of resistance to cry1ab. patterns of inheritance of resistance were similar in the two resistant strains. the progeny of reciprocal f1 crosses (resistant male x susceptible female and vice vers ... | 2006 | 16686152 |
| frequency of resistance to bacillus thuringiensis toxin cry1ab in southern united states corn belt population of european corn borer (lepidoptera: crambidae). | the high-dose refuge resistance management strategy is the main approach used to delay resistance in targeted pests to bacillus thuringiensis (bt) toxins in transgenic crops. we used an f2 screen to test a critical assumption of the high-dose refuge strategy, which is that resistance allele (r) frequencies are initially rare (<10(-3)) in ostrinia nubilalis (hübner) (lepidoptera: crambidae) from the southern corn belt. we expanded the methodological scope of the f2 screen so that both males and f ... | 2006 | 16686153 |
| is resistance to bacillus thuringiensis endotoxin cry1ac associated with a change in the behavior of light brown apple moth larvae (lepidoptera: tortricidae)? | bacillus thuringiensis (bt)-resistant light brown apple moth, epiphyas postvittana (walker) (lepidoptera: tortricidae), created by selection of a laboratory colony with artificial diets containing the bt endotoxin cry1ac, were used to explore relationships between larval behavior and resistance to toxins. our hypothesis was that behavioral responses during the first days of exposure to diet are directly related to the toxicity of the diet, as measured by subsequent mortality. we tested two predi ... | 2006 | 16686154 |
| insecticidal activity of avidin combined with genetically engineered and traditional host plant resistance against colorado potato beetle (coleoptera: chrysomelidae) larvae. | colorado potato beetle, leptinotarsa decemlineata (say), is a destructive pest of potato, solanum tuberosum (l.), in north america. it is renowned for adapting to insecticides. with the arsenal of effective insecticides decreasing, it is important to consider alternative forms of control. biotin is an essential coenzyme for insect growth and development. avidin is a protein found in chicken egg that sequesters biotin and has shown insecticidal properties against a range of insect. we assessed th ... | 2006 | 16686156 |
| recent developments and future prospects in insect pest control in transgenic crops. | the adoption of insect-resistant transgenic crops has been increasing annually at double-digit rates since the commercial release of first-generation maize and cotton expressing a single modified bacillus thuringiensis toxin (bt) nine years ago. studies have shown that these bt crops can be successfully deployed in agriculture, which has led to a decrease in pesticide usage, and that they are environmentally benign. however, the sustainability and durability of pest resistance continues to be di ... | 2006 | 16690346 |
| composition of bacillus species in aerosols from 11 u.s. cities. | a pcr-based heteroduplex assay was used to determine the presence and composition of bacillus species in 11,059 environmental protection agency pm2.5 aerosol samples from 11 u.s. cities. the assay differentiated three groups: type a containing bacillus anthracis and very closely related, often pathogenic, bacillus cereus and bacillus thuringiensis strains; type b containing other b. cereus and b. thuringiensis strains; and a third group of more-distantly related bacillus species. eight of the 11 ... | 2006 | 16696702 |
| adhesion and cytotoxicity of bacillus cereus and bacillus thuringiensis to epithelial cells are flha and plcr dependent, respectively. | some bacteria of the bacillus cereus group are enteropathogens. the first cells encountered by bacteria following oral contamination of the host are epithelial cells. we studied the capacity of these bacteria to adhere to epithelial cells and the consequences of this interaction. we found that cell adhesion is strain dependent and that a strain mutated in flha, which encodes a component of flagellum-apparatus formation, is impaired in adhesion, suggesting that flagella are important virulence fa ... | 2006 | 16697234 |
| detection of antibiotic-related genes from bacterial biocontrol agents with polymerase chain reaction. | pseudomonas chlororaphis pa23, pseudomonas spp. strain df41, and bacillus amyloliquefaciens bs6 consistently inhibit infection of canola petals by sclerotinia sclerotiorum in both greenhouse and field experiments. bacillus thuringiensis bs8, bacillus cereus l, and bacillus mycoides s have shown significant inhibition against s. sclerotiorum on plate assays. the presence of antibiotic biosynthetic or self-resistance genes in these strains was investigated with polymerase chain reaction and, in on ... | 2006 | 16699573 |
| occurrence of parasporin-producing bacillus thuringiensis in vietnam. | a total of 63 bacillus thuringiensis isolates were recovered from urban soils of hanoi, vietnam. of these, 34 were identified to 12 h serogroups. none of the isolates showed larvicidal activities against three lepidopterous insects. three isolates belonging to the two serovars, colmeri (h21) and konkukian (h34), were highly toxic to larvae of the mosquito aedes aegypti. parasporal inclusion proteins of four isolates exhibited cytocidal activities against hela cells. immunologically, proteins of ... | 2006 | 16699587 |
| frequency and fitness cost of resistance to bacillus thuringiensis in chrysomela tremulae (coleoptera: chrysomelidae). | the "high dose-refuge" (hdr) strategy is commonly recommended and currently used for delaying or preventing pest adaptation to transgenic plants producing bacillus thuringiensis (bt) toxins. the efficiency of this strategy depends, among other factors, on the initial frequency of bt resistance alleles and on the fitness costs associated with these alleles. two years ago, an allele conferring resistance to bt poplar was detected in a french population of the poplar pest chrysomela tremulae f. alt ... | 2006 | 16705321 |
| identification and characterization of a germination operon from bacillus thuringiensis. | spore cortex-lytic enzymes are essential for germination in bacillus. a homologue of the cwlj gene involved in spore germination was isolated from bacillus thuringiensis. the deduced product of this gene exhibits striking sequence similarity to cwlj of bacillus subtilis. another open reading frame (orf) was found 27 bp downstream of cwlj and its deduced product shows high similarity to ywdl of b. subtilis. reverse transcription polymerase chain reaction analysis indicated that cwlj and ywdl form ... | 2006 | 16710636 |
| identification of a bacillus thuringiensis cry11ba toxin-binding aminopeptidase from the mosquito, anopheles quadrimaculatus. | aminopeptidase n (apn) type proteins isolated from several species of lepidopteran insects have been implicated as bacillus thuringiensis (bt) toxin-binding proteins (receptors) for cry toxins. we examined brush border membrane vesicle (bbmv) proteins from the mosquito anopheles quadrimaculatus to determine if apns from this organism would bind mosquitocidal cry toxins that are active to it. | 2006 | 16716213 |
| effects of genetic modification on herbivore-induced volatiles from maize. | large-scale implementation of transgenic crop varieties raises concerns about possible nontarget effects on other organisms. this study examines the effects of genetic modification on plant volatile production and its potential impact on arthropod population dynamics. we compared herbivore-induced volatile emissions from bacillus thuringiensis berliner (bt) maize plants to those from a nontransformed isoline following exposure to various types of leaf damage. when equal numbers of helicoverpa ze ... | 2006 | 16718567 |
| resistance evolution to bt crops: predispersal mating of european corn borers. | over the past decade, the high-dose refuge (hdr) strategy, aimed at delaying the evolution of pest resistance to bacillus thuringiensis (bt) toxins produced by transgenic crops, became mandatory in the united states and is being discussed for europe. however, precopulatory dispersal and the mating rate between resident and immigrant individuals, two features influencing the efficiency of this strategy, have seldom been quantified in pests targeted by these toxins. we combined mark-recapture and ... | 2006 | 16719560 |
| lactobacillus plantarum gene clusters encoding putative cell-surface protein complexes for carbohydrate utilization are conserved in specific gram-positive bacteria. | genomes of gram-positive bacteria encode many putative cell-surface proteins, of which the majority has no known function. from the rapidly increasing number of available genome sequences it has become apparent that many cell-surface proteins are conserved, and frequently encoded in gene clusters or operons, suggesting common functions, and interactions of multiple components. | 2006 | 16723015 |
| impact of transgenic bt maize residues on the mycotoxigenic plant pathogen fusarium graminearum and the biocontrol agent trichoderma atroviride. | transformation of maize with genes encoding for insecticidal crystal (cry) proteins from bacillus thuringiensis (bt) could have an impact on the saprophytic survival of plant pathogens and their antagonists on crop residues. we assessed potential effects on the mycotoxin deoxynivalenol (don)-producing wheat and maize pathogen fusarium graminearum and on the biocontrol agent trichoderma atroviride. purified cry1ab protein caused no growth inhibition of these fungi on agar plates. cry1ab concentra ... | 2006 | 16738384 |
| prevention and control of pests and diseases. | a well-controlled growth environment with plants that are not unduly stressed is essential for arabidopsis molecular biology research. even if they do not kill the plants outright, insect pests and microbial pathogens can cause subtle changes in gene expression or plant metabolism that affect experimental results. therefore, regular scouting for infestations, frequent cleaning of plant growth areas, proper disposal of dead or diseased plant material, and controlled access to the greenhouses or g ... | 2006 | 16739564 |
| acrylic acid removal by acrylic acid utilizing bacteria from acrylonitrile-butadiene-styrene resin manufactured wastewater treatment system. | the aim of this study is to isolate the acrylic acid utilizing bacteria from the abs resin manufactured wastewater treatment system. the bacteria should have the ability to remove acrylic acid and tolerate the acrylonitrile and acrylamide toxicity. the aim is also to understand the performance of isolated pure strain for treating different initial acrylic acid concentrations from synthetic wastewater. the results are: twenty strains were isolated from the abs resin manufactured wastewater treatm ... | 2006 | 16749456 |
| novel preparation and characterization of the alpha4-loop-alpha5 membrane-perturbing peptide from the bacillus thuringiensis cry4ba delta-endotoxin. | helices 4 and 5 of the bacillus thuringiensis cry4ba delta-endotoxin have been shown to be important determinants for mosquito-larvicidal activity, likely being involved in membrane-pore formation. in this study, the cry4ba mutant protein containing an additional engineered tryptic cleavage site was used to produce the alpha4-alpha5 hairpin peptide by an efficient alternative strategy. upon solubilization of toxin inclusions expressed in escherichia coli and subsequent digestion with trypsin, th ... | 2006 | 16756755 |
| invasion of pests resistant to bt toxins can lead to inherent non-uniqueness in genetically modified bt-plant dynamics: mathematical modeling. | genetically modified crops are effective pest management tools for worldwide growers. however, there is a concern that pests may develop resistance to bt-toxins produced by genetically modified bt-plants. we study the impact of the bt-resistant pests on bt-crops. furthermore, the dynamics of the bt-plant-bt-susceptible insects-bt-resistant insects system is analysed and it is shown that throughout the insect reproduction period the plant biomass dynamics resulting from invasion of bt-resistant i ... | 2006 | 16757001 |
| effects of cry1ac toxin of bacillus thuringiensis and nuclear polyhedrosis virus of helicoverpa armigera (hübner) (lepidoptera: noctuidae) on larval mortality and pupation. | in the laboratory, the percentage mortality and pupation of helicoverpa armigera (hübner) were investigated when larvae were exposed to cry1ac of bacillus thuringiensis berliner, nuclear polyhedrosis virus of h. armigera (hanpv) or cry1ac and hanpv together. the results revealed that interactions between cry1ac and hanpv varied with bioassay method and concentration of the suspension. when larvae were infected using a suspension containing both hanpv and cry1ac, most combinations of cry1ac (62.5 ... | 2006 | 16770833 |
| laboratory and semi-field evaluation of mosquito dunks against aedes aegypti and aedes albopictus larvae (diptera: culicidae). | laboratory bioassays and semi-field studies were conducted on the efficacy and longevity of mosquito dunks (7,000 itu/mg bti) in order to determine the concentration-response relationship and the effectiveness on the potency of the bti product against aedes mosquito species based on the who protocol standard methods and to determine the longevity of release for this product against ae. aegypti mosquito larvae in water storage containers. this bio-potency study with the late 3rd instar larvae of ... | 2006 | 16771214 |
| malaysian mosquitocidal soil bacterium (bacillus thuringiensis) strains with selective hemolytic and lectin activity against human and rat erythrocytes. | the objective of this study is to determine the role of carbohydrates on the toxic effect of parasporal inclusion proteins isolated from malaysian mosquitocidal bacillus thuringiensis (bt) strains on erythrocytes (human and rat). dose response analyses on the effect of these parasporal inclusions on human and rat erythrocytes suggest that toxin action is selective depending on bacterial strains and source of erythrocytes. results from this study suggest bt toxin is a lectin which recognizes spec ... | 2006 | 16771215 |
| characterization of bacillus thuringiensis strain bt185 toxic to the asian cockchafer: holotrichia parallela. | a new bacillus thuringiensis strain, bt185, was isolated from hebei soil samples in china. observations after transmission electron microscopy found that the strain produced spherical parasporal inclusions similar to that of the b. thuringiensis subsp. japonensis buibui strain, which showed toxicity to both anomala corpulenta and popillia japonica. the plasmid profile seen on an agarose gel revealed that bt185 contained six large bands of 191 kb, 161 kb, 104 kb, 84 kb, 56 kb, and 37 kb. sodium d ... | 2006 | 16775781 |
| cry1aa lacks stability elements at its 5'-utr but integrity of its transcription terminator is critical to prevent decay of its transcript. | we analyzed the influence of the 5' and 3' untranslated regions of the bacillus thuringiensis cry1aa on its mrna stability. although the cry1aa gene has a stable transcript (8 min), its 5' utr did not provide stability to the reporter gene uida. stability of cry1aa could be increased to 40 min by addition of an sp82 stability element at the 5' utr, suggesting that once the 5' and 3' ends were protected initiation of decay could be effectively blocked. we generated mutations in the transcription ... | 2006 | 16775783 |
| structural and functional analysis of the pre-pore and membrane-inserted pore of cry1ab toxin. | bacillus thuringiensis produces insecticidal cry proteins that are active against different insect species. the primary action of cry toxins is to lyse midgut epithelial cells in the target insect by forming lytic pores on the apical membrane. after interaction with cadherin receptor, cry proteins undergo conformational changes from a monomeric structure to a pre-pore-oligomeric form that is able to interact with a second gpi-anchored aminopeptidase-n receptor and then insert into lipid membrane ... | 2006 | 16777138 |
| pathogenicity of intrathoracically administrated bacillus thuringiensis spores in blatta orientalis. | the ability of bacillus thuringiensis to produce septicaemia in periplaneta americana and blatta orientalis has been investigated. spores and crystals from several wild-type strains as well as spores of a b. thuringiensis crystal-deficient mutant, were first orally administrated at high doses, and no significant mortality was recorded. intrathoracic injection of spore suspensions in p. americana revealed that this species is not very susceptible to b. thuringiensis spores. b. orientalis, by cont ... | 2006 | 16777139 |
| vip3a is responsible for the potency of bacillus thuringiensis 9816c culture supernatant against helicoverpa armigera and spodoptera exigua. | culture supernatant of bacillus thuringiensis 9816c had high toxicity against helicoverpa armigera and spodoptera exigua. however, it lost insecticidal activities after being bathed in boiling water for 5 min. acrystalliferous mutants of bt9816c (bt9816c-np1 and bt9816c-np2) cured of its endogenous plasmids no longer possessed vip3a gene and toxicity. the 89 kd protein which existed in bt9816c supernatant disappeared in the two mutants' supernatant; nevertheless, the two mutants still exhibited ... | 2006 | 16778351 |
| mycotoxin reduction in bt corn: potential economic, health, and regulatory impacts. | genetically modified (gm) bt corn, through the pest protection that it confers, has lower levels of mycotoxins: toxic and carcinogenic chemicals produced as secondary metabolites of fungi that colonize crops. in some cases, the reduction of mycotoxins afforded by bt corn is significant enough to have an economic impact, both in terms of domestic markets and international trade. in less developed countries where certain mycotoxins are significant contaminants of food, bt corn adoption, by virtue ... | 2006 | 16779644 |
| effects of commercial microbial products on the immune system of elliptio complanata mussels. | | 2006 | 16786456 |
| laboratory and field tests of spray-dried and granular formulations of a bacillus thuringiensis strain with insecticidal activity against the sugarcane borer. | formulations of bacillus thuringiensis berliner (bt) with insecticidal activity against the sugarcane borer, diatraea saccharalis fabricius (lepidoptera: pyralidae), were developed and tested under laboratory and field conditions. the formulations were prepared using biodegradable polymers such as modified corn starch as an encapsulating agent, gelatin as an adherent, powdered sugarcane as a feeding stimulant and a bt var. kurstaki gm-34 strain from a non-sugarcane region as the active ingredien ... | 2006 | 16786544 |
| a mechanism of cell death involving an adenylyl cyclase/pka signaling pathway is induced by the cry1ab toxin of bacillus thuringiensis. | many pathogenic organisms and their toxins target host cell receptors, the consequence of which is altered signaling events that lead to aberrant activity or cell death. a significant body of literature describes various molecular and cellular aspects of toxins associated with bacterial invasion, colonization, and host cell disruption. however, there is little information on the molecular and cellular mechanisms associated with the insecticidal action of bacillus thuringiensis (bt) cry toxins. r ... | 2006 | 16788061 |
| the enhancin-like metalloprotease from the bacillus cereus group is regulated by the pleiotropic transcriptional activator plcr but is not essential for larvicidal activity. | bacillus cereus group bacteria produce virulence factors. many of these are regulated by the pleiotropic transcriptional activator plcr, which is implicated in insect virulence. in silico analysis of the b. cereus strain atcc14579 genome showed an enhancin-like gene preceded by a typical plcr binding sequence. the gene is predicted to encode a polypeptide showing 23-25% identity with enhancins from several baculoviruses and 31% with that of yersinia pestis. viral enhancin acts after oral infecti ... | 2006 | 16790012 |
| antimicrobial activities of human beta-defensins against bacillus species. | natural defences in the human body function to protect us from numerous environmental toxins and exposure to potential harmful biological agents. an important frontline defence is antimicrobial peptides. these peptides occur at environmental interfaces and serve to limit bacterial invasion. there has been little work comparing specific peptides as potential antimicrobial compounds. in this study, we evaluated the antimicrobial activity of peptides from the human beta-defensin (hbd) family agains ... | 2006 | 16797165 |
| expression of cry1ac cadherin receptors in insect midgut and cell lines. | cadherin-like proteins have been identified as putative receptors for the bacillus thuringiensis cry1a proteins in heliothis virescens and manduca sexta. immunohistochemistry showed the cadherin-like proteins are present in the insect midgut apical membrane, which is the target site of cry toxins. this subcellular localization is distinct from that of classical cadherins, which are usually present in cell-cell junctions. immunoreactivity of the cadherin-like protein in the insect midgut was enha ... | 2006 | 16797582 |
| cry toxin mode of action in susceptible and resistant heliothis virescens larvae. | many pest insect species are effectively controlled by bacillus thuringiensis (bt) cry toxins delivered in plants and biopesticides. since the insect midgut epithelium contains receptors and other molecules that determine bt toxicity, characterization of these molecules is necessary for sustained usage of bt toxins. studies of bt susceptible and resistant strains of heliothis virescens have provided insights into resistance mechanisms and toxin receptors. for example, the first gene identified a ... | 2006 | 16797583 |
| chemical-induced autoexcision of selectable markers in elite tomato plants transformed with a gene conferring resistance to lepidopteran insects. | marker-free transgenic tomato plants harboring a synthetic bacillus thuringiensis endotoxin gene, cryiac, were obtained by using a chemically regulated, cre/loxp-mediated site-specific dna recombination system, in which the selectable marker neomycin phosphotransferase gene flanked by two directly oriented loxp sites was located between the cauliflower mosaic virus 35s promoter and a promoterless cryiac. upon induction by 2 microm beta-estradiol, sequences encoding the selectable marker and cre ... | 2006 | 16802102 |
| pronase digestion of brush border membrane-bound cry1aa shows that almost the whole activated cry1aa molecule penetrates into the membrane. | bacillus thuringiensis insecticidal proteins, cry toxins, following ingestion by insect larvae, induce insecticidal effect by penetrating the brush border membranes (bbm) of midgut epithelial cells. purified, activated b. thuringiensis cry1aa bound to bombyx mori bbmv or unbound cry1aa were vigorously digested with pronase. both digests were compared by western blotting. free cry1aa was digested to alpha-helix and/or to amino acids at 1 mg pronase/ml within 2.4 h at 37 degrees c. whereas, bbmv-b ... | 2006 | 16807030 |
| cytocidal actions of parasporin-2, an anti-tumor crystal toxin from bacillus thuringiensis. | parasporin-2, a new crystal protein derived from noninsecticidal and nonhemolytic bacillus thuringiensis, recognizes and kills human liver and colon cancer cells as well as some classes of human cultured cells. here we report that a potent proteinase k-resistant parasporin-2 toxin shows specific binding to and a variety of cytocidal effects against human hepatocyte cancer cells. cleavage of the n-terminal region of parasporin-2 was essential for the toxin activity, whereas c-terminal digestion w ... | 2006 | 16809341 |
| diabrotica virgifera virgifera (coleoptera: chrysomelidae) larval feeding behavior on transgenic maize (mon 863) and its isoline. | diabrotica species (coleoptera: chrysomelidae) larval behavior studies have posed a challenge to researchers because of the subterranean life cycle of this pest. to fully understand how the western corn rootworm, diabrotica virgifera virgifera leconte, injures the maize, zea mays l., root system, its behavior must be studied. for example, larvae that can detect an area of the root that has a lower amount of toxin, whether from an insecticide or a transgenic maize plant, have an increased chance ... | 2006 | 16813304 |
| cannibalism of helicoverpa zea (lepidoptera: noctuidae) from bacillus thuringiensis (bt) transgenic corn versus non-bt corn. | because of the importance of cannibalism in population regulation of helicoverpa zea (boddie) (lepidoptera: noctuidae) in corn, zea mays l., it is useful to understand the interactions between bacillus thuringiensis (bt) transgenic corn and cannibalism. to determine the effects of bt corn on cannibalism in h. zea, pairs of the same or different instars were taken from bt or non-bt corn and placed on artificial diet in proximity. cannibalism occurred in 91% of pairs and was approximately 7% great ... | 2006 | 16813305 |
| potential of selective insecticides for managing uraba lugens (lepidoptera: nolidae) on eucalypts. | the leaf skeletonizer uraba lugens walker (lepidoptera: nolidae), an australian species, locally known as "gumleaf skeletonizer", is well established in new zealand. this insect has the potential to become a serious pest of forestry and amenity eucalypts (eucalyptus spp.) and is the focus of a long-term management program. the use of synthetic chemical or biological insecticides is one possible control method within an integrated control program. a series of dose-response trials were conducted u ... | 2006 | 16813312 |
| resistance monitoring of helicoverpa armigera (lepidoptera: noctuidae) to bt insecticidal protein during 2001-2004 in china. | susceptibility of helicoverpa armigera (hübner) (lepidoptera: noctuidae) field populations to the crylac toxin of bacillus thuringiensis berliner (bt) were monitored from 1997 to 2004 in china. during 2001-2004, 53 strains from the bt cotton planting region were sampled. the range of concentration producing 50% inhibition of larval development to third instar (ic50) values among different populations in 2001, 2002, 2003, and 2004 was 0.014-0.046, 0.010-0.062, 0.005-0.062, and 0.005-0.035 microg/ ... | 2006 | 16813327 |
| effect of entomopathogenic nematodes on the fitness cost of resistance to bt toxin crylac in pink bollworm (lepidoptera: gelechiidae). | the widespread use of crop plants genetically engineered to produce toxins from the bacterium bacillus thuringiensis (bt) imposes selection on insect populations to evolve resistance. the pink bollworm, pectinophora gossypiella (saunders) (lepidoptera: gelechiidae), is a major pest of cotton in the southwestern united states that is currently controlled with transgenic cotton that produces bt toxin cry1ac. previously reported theoretical work suggests that, in conjunction with a high dose/refuge ... | 2006 | 16813331 |
| effect of bacillus thuringiensis cry3bb1 protein on the feeding behavior and longevity of adult western corn rootworms (coleoptera: chrysomelidae). | the first transgenic corn hybrids expressing the bacillus thuringiensis (bt) cry3bb1 protein to control corn rootworm (diabrotica spp.) larvae were registered for commercial use in 2003. this study was conducted to investigate the effect of cry3bb1 protein in combination with a cucurbitacin bait on adult feeding and longevity of both organophosphate-resistant and -susceptible western corn rootworms, diabrotica virgifera virgifera leconte (coleoptera: chrysomelidae). in choice and no-choice tests ... | 2006 | 16813332 |
| differences in susceptibility and physiological fitness of mexican field trichoplusia ni strains exposed to bacillus thuringiensis. | the use of different commercial bacillus thuringiensis (bt) products in the bajio guanajuatense area in mexico began 12 yr ago, and resistance to bt in this area has been reported for plutella xylostella (l.) the current study provides a baseline response and resistance potential to bt in field and laboratory strains of bajio trichoplusia ni (hübner). differences in susceptibility to bt among t. ni populations were observed. t. ni neonates collected in romita, guanajuato, were more susceptible t ... | 2006 | 16813334 |
| effect of resistance to bacillus thuringiensis cotton on pink bollworm (lepidoptera: gelechiidae) response to sex pheromone. | fitness costs associated with resistance to transgenic crops producing toxins from bacillus thuringiensis (bt) could reduce male response to pheromone traps. such costs would cause underestimation of resistance frequency if monitoring was based on analysis of males caught in pheromone traps. to develop a dna-based resistance monitoring program for pink bollworm, pectinophora gossypiella (saunders) (lepidoptera: gelechiidae), we compared the response to pheromone traps of males with and without c ... | 2006 | 16813335 |
| sequence diversity of the bacillus thuringiensis and b. cereus sensu lato flagellin (h antigen) protein: comparison with h serotype diversity. | we set out to analyze the sequence diversity of the bacillus thuringiensis flagellin (h antigen [hag]) protein and compare it with h serotype diversity. some other bacillus cereus sensu lato species and strains were added for comparison. the internal sequences of the flagellin (hag) alleles from 80 bacillus thuringiensis strains and 16 strains from the b. cereus sensu lato group were amplified and cloned, and their nucleotide sequences were determined and translated into amino acids. the flagell ... | 2006 | 16820457 |
| molecular and insecticidal characterization of a cry1i protein toxic to insects of the families noctuidae, tortricidae, plutellidae, and chrysomelidae. | the most notable characteristic of bacillus thuringiensis is its ability to produce insecticidal proteins. more than 300 different proteins have been described with specific activity against insect species. we report the molecular and insecticidal characterization of a novel cry gene encoding a protein of the cry1i group with toxic activity towards insects of the families noctuidae, tortricidae, plutellidae, and chrysomelidae. pcr analysis detected a dna sequence with an open reading frame of 2. ... | 2006 | 16820473 |
| an ecological risk assessment of cry1f maize pollen impact to pale grass blue butterfly. | the intrinsic toxicity of lepidopteran-active bt proteins necessitates assessment of non-target risks associated with environmental release of transgenic crops expressing these proteins. principles of ecological risk assessment provide a means for assessing non-target risks when information regarding exposure to the toxin and species-specific effects are lacking. this is shown for the case of bt cry1f maize release in japan, where off-field pollen dissemination and effect on butterfly species is ... | 2006 | 16827552 |
| influence of the biophysical and biochemical environment on the kinetics of pore formation by cry toxins. | the effect of bacillus thuringiensis toxins on the permeability of the luminal membrane of manduca sexta midgut columnar epithelial cells is strongly influenced by several biophysical and biochemical factors, including ph, ionic strength, and divalent cations, suggesting an important role for electrostatic interactions. the influence of these factors can differ greatly, however, depending on the toxin being studied, even for closely related toxins such as cry1ac and cry1ca. in the present study, ... | 2006 | 16831627 |