Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
|---|
| population structure and evolution of the bacillus cereus group. | representative strains of the bacillus cereus group of bacteria, including bacillus anthracis (11 isolates), b. cereus (38 isolates), bacillus mycoides (1 isolate), bacillus thuringiensis (53 isolates from 17 serovars), and bacillus weihenstephanensis (2 isolates) were assigned to 59 sequence types (sts) derived from the nucleotide sequences of seven alleles, glpf, gmk, ilvd, pta, pur, pyca, and tpi. comparisons of the maximum likelihood (ml) tree of the concatenated sequences with individual ge ... | 2004 | 15547268 |
| histopathological and ultrastructural effects of delta-endotoxins of bacillus thuringiensis serovar israelensis in the midgut of simulium pertinax larvae (diptera, simuliidae). | the bacterium bacillus thuringiensis (bt) produces parasporal crystals containing delta-endotoxins responsible for selective insecticidal activity on larvae. upon ingestion, these crystals are solubilized in the midgut lumen and converted into active toxins that bind to receptors present on the microvilli causing serious damage to the epithelial columnar cells. we investigated the effect of these endotoxins on larvae of the simulium pertinax, a common black fly in brazil, using several concentra ... | 2004 | 15543412 |
| bollgard ii cotton: compositional analysis and feeding studies of cottonseed from insect-protected cotton (gossypium hirsutum l.) producing the cry1ac and cry2ab2 proteins. | bollgard ii cotton event 15985 producing the cry1ac and cry2ab2 proteins has been developed by genetic modification to broaden the spectrum of insects to which the plant is tolerant and to provide an insect resistance management tool to impede the onset of resistance. the purpose of this study was to evaluate the composition and nutrition of bollgard ii cotton, relative to the use for food and animal feed, compared to that of conventional cotton varieties. compositional analyses were conducted t ... | 2004 | 15537305 |
| insecticide resistance in alabama and florida mosquito strains of aedes albopictus. | the susceptibility of four strains of aedes albopictus (skuse) to permethrin, deltamethrin, resmethrin, chlorpyrifos, malathion, propoxur, fipronil, imidacloprid, spinosad, and bacillus thuringiensis variety israelensis (bti) was determined. the hamaal and mamaal strains were collected in 2002 and 2003, respectively, from huntsville and mobile, al, and the vbfmaal and sfmaal strains were collected in 1998 from vero beach and southern florida, respectively. the hamaal strain showed a 22-fold elev ... | 2004 | 15535626 |
| synergy between toxins of bacillus thuringiensis subsp. israelensis and bacillus sphaericus. | synergistic interactions among the multiple endotoxins of bacillus thuringiensis subsp. israelensis de barjac play an important role in its high toxicity to mosquito larvae and the absence of insecticide resistance in populations treated with this bacterium. a lack of toxin complexity and synergism are the apparent causes of resistance to bacillus sphaericus neide in particular culex field populations. to identify endotoxin combinations of the two bacillus species that might improve insecticidal ... | 2004 | 15535624 |
| cyt1a from bacillus thuringiensis restores toxicity of bacillus sphaericus against resistant culex quinquefasciatus (diptera: culicidae). | the 2362 strain of bacillus sphaericus, which produces a binary toxin highly active against culex mosquitoes, has been developed recently as a commercial larvicide. it is being used currently in operational mosquito control programs in several countries including brazil, france, india, and the united states. laboratory studies have shown that mosquitoes can develop resistance to b. sphaericus, and low levels of resistance have already been reported in field populations in brazil, france, and ind ... | 2000 | 15535584 |
| oligomerization triggers binding of a bacillus thuringiensis cry1ab pore-forming toxin to aminopeptidase n receptor leading to insertion into membrane microdomains. | bacillus thuringiensis cry1a toxins, in contrast to other pore-forming toxins, bind two putative receptor molecules, aminopeptidase n (apn) and cadherin-like proteins. here we show that cry1ab toxin binding to these two receptors depends on the toxins' oligomeric structure. toxin monomeric structure binds to bt-r1, a cadherin-like protein, that induces proteolytic processing and oligomerization of the toxin (gomez, i., sanchez, j., miranda, r., bravo a., soberon, m., febs lett. (2002) 513, 242-2 ... | 2004 | 15533304 |
| larvicidal persistence of formulations of bacillus thuringiensis var. israelensis to control larval aedes aegypti. | after detection of resistance to the organophosphate temephos in populations of aedes aegypti in brazil, corncob granule (cg) and water-dispersible granule (wdg) formulations of bacillus thuringiensis var. israelensis (bti) were introduced in routine focal treatments. larvicidal persistence and the influence of exposure to sunlight on vectobac formulations of bti were compared in 250-liter fiberglass water containers. production of pupal ae. aegypti in containers was used to indicate control. in ... | 2004 | 15532933 |
| capacity of bacillus thuringiensis s-layer protein displaying polyhistidine peptides on the cell surface. | s-layer protein of bacillus thuringiensis strain ctc was used as the carrier protein to display polyhistidine (poly[6his]) peptides on the cell surface. poly(6his)n was fused with s-layer protein at two different sites, inserting just downstream of the s-layer protein homologous domain (slh) and replacing the non-slh region of s-layer protein, respectively. the two series chimeric proteins were both expressed by crystal negative b. thuringiensis strain 4q7 and strain 171, respectively, as shown ... | 2004 | 15531784 |
| display of biologically functional insecticidal toxin on the surface of lambda phage. | the successful use of bacillus thuringiensis insecticidal toxins to control agricultural pests could be undermined by the evolution of insect resistance. under selection pressure in the laboratory, a number of insects have gained resistance to the toxins, and several cases of resistance in the diamondback moth have been reported from the field. the use of protein engineering to develop novel toxins active against resistant insects could offer a solution to this problem. the display of proteins o ... | 2004 | 15528522 |
| antimicrobial effect of water extract of sumac (rhus coriaria l.) on the growth of some food borne bacteria including pathogens. | the antimicrobial effect of water extracts of sumac (rhus coriaria l.) at concentrations of 0.1%, 0.5%, 1.0%, 2.5% and 5.0% (w/v), non-neutralized and after neutralization to ph 7.2+/-0.1, was studied on the growth of 12 bacterial strains (six gram positive strains and six gram negative strains), mostly food borne including pathogens. it was found to be effective against all the test organisms with gram positive strains being more sensitive than gram negative strains. significant differences (p< ... | 2004 | 15527919 |
| dna-based detection of bt resistance alleles in pink bollworm. | evolution of resistance by pests is the main threat to long-term insect control by transgenic crops that produce bacillus thuringiensis (bt) toxins. we previously identified three mutant alleles (r1, r2, r3) of a cadherin gene in pink bollworm (pectinophora gossypiella) linked with recessive resistance to bt toxin cry1ac and survival on transgenic bt cotton. here we describe a polymerase chain reaction (pcr)-based method that detects the mutation in genomic dna of each of the three resistant all ... | 2004 | 15522618 |
| the hevcalp protein mediates binding specificity of the cry1a class of bacillus thuringiensis toxins in heliothis virescens. | retrotransposon-mediated disruption of the btr-4 gene encoding the heliothis virescens cadherin-like protein (hevcalp) is linked to high levels of resistance in the yhd2 strain to cry1ac toxin from bacillus thuringiensis. this suggests that hevcalp functions as a cry1ac toxin receptor on the surface of midgut cells in susceptible larvae and that the btr-4 gene disruption eliminates this protein in resistant larvae. however, cry1ac toxin binding to hevcalp is yet to be reported. we used the polym ... | 2004 | 15518581 |
| boiling and bacillus spores. | 2004 | 15515252 | |
| the high-resolution architecture and structural dynamics of bacillus spores. | the capability to image single microbial cell surfaces at nanometer scale under native conditions would profoundly impact mechanistic and structural studies of pathogenesis, immunobiology, environmental resistance, and biotransformation. here, using in vitro atomic force microscopy, we have directly visualized high-resolution native structures of bacterial endospores, including the exosporium and spore coats of four bacillus species in air and water environments. our results demonstrate that the ... | 2005 | 15501940 |
| unfolding events in the water-soluble monomeric cry1ab toxin during transition to oligomeric pre-pore and membrane-inserted pore channel. | the insecticidal crystal (cry) proteins produced by bacillus thuringiensis undergo several conformational changes from crystal inclusion protoxins to membrane-inserted channels in the midgut epithelial cells of the target insect. here we analyzed the stability of the different forms of cry1ab toxin, monomeric toxin, pre-pore complex, and membrane-inserted channel, after urea and thermal denaturation by monitoring intrinsic tryptophan fluorescence of the protein and 1-anilinonaphthalene-8-sulfoni ... | 2004 | 15498772 |
| galnac pretreatment inhibits trapping of bacillus thuringiensis cry1ac on the peritrophic membrane of bombyx mori. | bombyx mori (shunreixshogetsu) is sensitive to cry1aa and resistant to cry1ac, both insecticidal proteins of bacillus thuringiensis. cry1aa passed through the peritrophic membrane (pm) much faster (0.37 microg/mm2 pm/h) than cry1ac (0.05 microg/mm2 pm/h) during the initial observation period. both cry1aa and cry1ac bound to the pm but only the binding of cry1ac was specifically inhibited by n-acetylgalactosamine (galnac). when cry1ac was pretreated with galnac, cry1ac permeated the pm much faste ... | 2004 | 15498557 |
| high-resolution 31p field cycling nmr as a probe of phospholipid dynamics. | we have used high-resolution field-cycling 31p nmr spectroscopy to measure spin-lattice relaxation rates (r1 = 1/t1) of multicomponent phospholipid vesicle and micelle samples over a large field range, from 0.1 to 11.7 t. the shape of the curve for r1 as a function of field and a model-free analysis were used to extract tauc, a correlation time for each type of phospholipid molecule in the bilayer that is likely to reflect rotation of the molecule about the axis perpendicular to the membrane sur ... | 2004 | 15493936 |
| structural implication of the induced immune response by bacillus thuringiensis cry proteins: role of the n-terminal region. | the potential role of the regions (carboxil and amino) of the cry proteins in the ability of these proteins to elicit strong immune responses was investigated. intraperitoneal immunization of mice with the homologous cry1a protoxins (130-133 kda), with the long c-terminal half gave rise mostly to similar, strong serum and mucosal igg and igm antibody response but a lower induction of these ab by intranasal route. remarkably, cry3a protoxin, devoid of c-terminal half was able to induce a signific ... | 2004 | 15482853 |
| a heat inducible tyrosinase with distinct properties from bacillus thuringiensis. | the objective of this work was to purify the tyrosinase from bacillusthuringiensis subsp. kurstaki (bt) (cctcc ab 90010) and study its enzymatic properties. | 2004 | 15482430 |
| purification and characterization of a lipopeptide produced by bacillus thuringiensis cmb26. | to isolate an antagonist for use in the biological control of phytopathogenic fungi including colletotrichum gloeosporioides, then to purify and characterize the biocontrol agent produced by the antagonist. | 2004 | 15479409 |
| managing the evolution of bacillus thuringiensis resistance in natural populations of the european corn borer, ostrinia nubilalis: host plant, host race and pherotype of adult males at aggregation sites. | the european corn borer (ecb) consists of at least two, genetically differentiated host races: one feeding on maize, the other feeding on mugwort and hop. it is unclear to what extent individuals feeding on these, or other host plants, contribute to natural ecb populations. the mechanisms underlying the genetic differentiation between both races are not well understood; they may include sexual attraction via different pheromone blends (e or z) and differences in the location of mating sites. we ... | 2004 | 15475339 |
| expression of bacillus anthracis protective antigen in transgenic chloroplasts of tobacco, a non-food/feed crop. | the centers for disease control (cdc) lists bacillus anthracis as a category a agent and estimates the cost of an anthrax attack to exceed us$ 26 billion per 100,000 exposed individuals. concerns regarding anthrax vaccine purity, a requirement for multiple injections, and a limited supply of the protective antigen (pa), underscore the urgent need for an improved vaccine. therefore, the 83 kda immunogenic bacillus anthracis protective antigen was expressed in transgenic tobacco chloroplasts. the ... | 2004 | 15474731 |
| genetically modified cotton and farmers' health in china. | this study provides the first evidence of a direct link between the adoption of a genetically modified (gm) crop and improvements in human health. estimation of the impact of bacillus thuringiensis (bt) cotton adoption on pesticide use from data from a survey of cotton farmers in northern china, 1999-2001, showed that bt cotton adoption reduced pesticide use. assessment of a health-production function showed that predicted pesticide use had a positive impact on poisoning incidence. taken togethe ... | 2004 | 15473084 |
| analysis of insecticidal proteins from bacillus thuringiensis and recombinant escherichia coli by capillary electrokinetic chromatography. | bacillus thuringiensis and recombinant escherichia coli proteinaceous protoxins were subject to proteolysis and analyzed by capillary electrokinetic chromatography. three resulting toxins (65 kda) were baseline-resolved within 22 min using a 10 mm borate, ph 11 separation buffer consisting of 25 mm sodium dodecyl sulfate (sds) and 30 mm phytic acid. the toxins displayed differential interactions with the sds and phytic acid phases to effect their separation. the ion-pairing interaction between t ... | 2004 | 15472953 |
| bacillus thuringiensis cry4a and cry4b mosquito-larvicidal proteins: homology-based 3d model and implications for toxin activity. | three-dimensional (3d) models for the 65-kda activated cry4a and cry4b delta-endotoxins from bacillus thuringiensis subsp. israelensis that are specifically toxic to mosquito-larvae were constructed by homology modeling, based on atomic coordinates of the cry1aa and cry3aa crystal structures. they were structurally similar to the known structures, both derived 3d models displayed a three-domain organization: the n-terminal domain (i) is a seven-helix bundle, while the middle and c-terminal domai ... | 2004 | 15469711 |
| aromaticity of tyr-202 in the alpha4-alpha5 loop is essential for toxicity of the bacillus thuringiensis cry4a toxin. | the current model for the mechanism of action of the bacillus thuringiensis cry delta-endotoxins involves the penetration of the alpha4-alpha5 hairpin into the target midgut epithelial cell membranes, followed by pore formation. in this study, pcr-based mutagenesis was employed to identify a critical residue within the alpha4-alpha5 loop of the 130kda cry4a mosquito-larvicidal protein. alanine-substitutions of two charged (asp-198 and asp-200) and four polar (asn-190, asn-195, tyr-201 and tyr-20 ... | 2004 | 15469709 |
| diversity of cry genes and genetic characterization of bacillus thuringiensis isolated from brazil. | two hundred and eighteen bacillus thuringiensis isolates from brazil were characterized by the presence of crystal protein genes by pcr with primers specific to different cry and cyt genes. among these isolates, 95 were selected according to their geographic origin for genetic characterization with the 16s rrna gene, rapd, and plasmid profile. isolates containing cry1 genes were the most abundant (48%) followed by the cry11 and cyt (7%) and cry8 genes (2%). finally, 40.3% of the isolates did not ... | 2004 | 15467786 |
| helix 4 mutants of the bacillus thuringiensis insecticidal toxin cry1aa display altered pore-forming abilities. | the role played by alpha-helix 4 of the bacillus thuringiensis toxin cry1aa in pore formation was investigated by individually replacing each of its charged residues with either a neutral or an oppositely charged amino acid by using site-directed mutagenesis. the majority of the resulting mutant proteins were considerably less toxic to manduca sexta larvae than cry1aa. most mutants also had a considerably reduced ability to form pores in midgut brush border membrane vesicles isolated from this i ... | 2004 | 15466558 |
| inheritance of resistance to bacillus thuringiensis subsp. kurstaki in trichoplusia ni. | the genetic inheritance of resistance to a commercial formulation of bacillus thuringiensis subsp. kurstaki was examined in a trichoplusia ni colony initiated from a resistant population present in a commercial vegetable greenhouse in british columbia, canada. progeny of f(1) reciprocal crosses and backcrosses between f(1) larvae and resistant (p(r)) and susceptible (p(s)) populations were assayed at different b. thuringiensis subsp. kurstaki concentrations. the responses of progeny of reciproca ... | 2004 | 15466525 |
| protein proteinase inhibitor genes in combat against insects, pests, and pathogens: natural and engineered phytoprotection. | the continual need to increase food production necessitates the development and application of novel biotechnologies to enable the provision of improved crop varieties in a timely and cost-effective way. a milestone in this field was the introduction of bacillus thuringiensis (bt) entomotoxic proteins into plants. despite the success of this technology, there is need for development of alternative strategies of phytoprotection. biotechnology offers sustainable solutions to the problem of pests, ... | 2004 | 15464737 |
| perspectives on the bacterial control of vectors in the tropics. | biological agents have not found wide application in the control of insects that transmit agents of human disease. fungal pathogens may have a potential for field use, but environmental constraints, lack of knowledge of their life cycle, or dependence on production in vivo, have prevented their widespread use. in fact, sporogenous bacteria are the only biological agents used on a large scale for the control of mosquitoes and blackflies that transmit diseases in the tropics. two bacteria, bacillu ... | 1992 | 15463539 |
| potential factors impacting season-long expression of cry1ac in 13 commercial varieties of bollgard cotton. | thirteen commercial varieties of transgenic cry1ac bacillus thuringiensis berliner (bt) cotton were examined across two sites in 2000 for potential factors that impact endotoxin expression. in all cases, two varieties (nucotn 33b and dp 458b/rr, delta & pineland co., scott, ms) expressed more cry1ac than the other 11 varieties in various plant structures. these two varieties share the same parental background (dp 5415). furthermore, when the next generation of plants were tested in the greenhous ... | 2001 | 15455073 |
| crystal structures and electron micrographs of fungal volvatoxin a2. | membrane adhesion and insertion of protein are essential to all organisms, but the underlying mechanisms remain largely unknown. membrane pore-forming toxins (pfts) are potential model systems for studying these mechanisms. we have determined the crystal structures of volvatoxin a2 (vva2), a fungal pft from volvariella volvacea, using br-multiple-wavelength anomalous diffraction (mad). the vva2 structures obtained at ph 4.6, ph 5.5 and ph 6.5 were refined to resolutions of 1.42 a, 2.6 a and 3.2 ... | 2004 | 15451675 |
| a spontaneous translational fusion of bacillus cereus plcr and papr activates transcription of plcr-dependent genes in bacillus anthracis via binding with a specific palindromic sequence. | transformation of bacillus anthracis with plasmid pute29-plcr-papr carrying the native bacillus cereus plcr-papr gene cluster did not activate expression of b. anthracis hemolysin genes, even though these are expected to be responsive to activation by the global regulator plcr. to further characterize the action of plcr, we examined approximately 3,000 b. anthracis transformants containing pute29-plcr-papr and found a single hemolytic colony. the hemolytic strain contained a plasmid having a spo ... | 2004 | 15385482 |
| field and storage testing bt potatoes for resistance to potato tuberworm (lepidoptera: gelichiidae). | potato tuberworm, phthorimaea operculella (zeller), is the most serious insect pest of potatoes worldwide. the introduction of the bacillus thuringiensis (bt) toxin gene through genetic engineering offers host plant resistance for the management of potato tuberworm. we report on the field and storage studies to evaluate bt-cry5 potato lines for resistance to potato tuberworm in egypt under natural infestations and their agronomic performance in both egypt and michigan. from 1997 to 2001, field e ... | 2004 | 15384356 |
| effects of insect population size on evolution of resistance to transgenic crops. | models of the evolution of insect resistance to transgenic crops have often assumed that population size is infinite or that carrying capacity is fixed. to evaluate potential effects of population size on resistance evolution, we conducted sensitivity analyses by using a stochastic, spatially explicit model based partly on the interaction between pink bollworm and bacillus thuringiensis (bt) cotton. we examined interactions of carrying capacity, region size, dispersal, and percentage of fields p ... | 2004 | 15384355 |
| growth, development, and survival of nosema pyrausta-infected european corn borers (lepidoptera: crambidae) reared on meridic diet and cry1ab. | transgenic corn, zea mays l., hybrids expressing crystal protein endotoxin genes from bacillus thuringiensis berliner are an increasingly popular tactic for managing the european corn borer, ostrinia nubilalis (hübner), in north america. o. nubilalis populations also are often vulnerable to the ubiquitous entomopathogenic microsporidium nosema pyrausta (paillot). we examined the effect of feeding meridic diet incorporated with purified cry1ab on growth, development, and survival of nosema-infect ... | 2004 | 15384327 |
| selection and heritability of resistance to bacillus thuringiensis subsp kurstaki and transgenic cotton in helicoverpa armigera (lepidoptera: noctuidae). | compared with an unselected susceptible population, a cotton bollworm, helicoverpa armigera (hübner), population selected for 22 generations with transgenic cotton leaves (modified cry1a) in the laboratory developed 11.0-fold resistance to cry1ac (one single-protein product mvpii). resistance to bacillus thuringiensis berliner subsp kurstaki (btk) was selected for 22 generations with a 5.2-fold increase in lc50. the estimated realized heritabilities (h2) of resistance for transgenic-cotton- and ... | 2004 | 15382503 |
| rapid report acetamiprid resistance and cross-resistance in the diamondback moth, plutella xylostella. | a 110-fold acetamiprid-resistant plutella xylostella (l) strain was established after four selection experiments (in five generations) on a 9.5-fold resistant colony in the laboratory. the resistant strain did not show cross-resistance to chlorfluazuron or bacillus thuringiensis subsp kurstaki berliner, but displayed low resistance to cartap and phenthoate. | 2004 | 15382497 |
| a novel bacillus thuringiensis (ps149b1) containing a cry34ab1/cry35ab1 binary toxin specific for the western corn rootworm diabrotica virgifera virgifera leconte forms ion channels in lipid membranes. | the binary bacillus thuringiensis ps149b1 insecticidal crystal (cry) protein is comprised of two components, cry34ab1, a 14-kda protein, and cry35ab1, a 44-kda protein, the combination of which forms a novel binary toxin active on western corn rootworm larvae. the permeabilizing behavior of the native binary toxin and its two individual components expressed as recombinant proteins was studied using calcein efflux determination in liposomes and by ion channel activity measurements in planar lipid ... | 2004 | 15379574 |
| ige sensitization to bacterial and fungal biopesticides in a cohort of danish greenhouse workers: the biogart study. | the use of biopesticides in agriculture may implicate new risks of work-related allergic reactions. | 2004 | 15376210 |
| modeling the invasion of recessive bt-resistant insects: an impact on transgenic plants. | there is a growing public concern on ecological and evolutionary consequence of the use of genetically modified organisms. we study the impact of bt-resistant pests on genetically modified bt crops. we develop and analyse a conceptual reaction-diffusion model of the bt crop-bt-susceptible insects-bt-resistant insects to simulate the invasion of bt-resistant insects. we show by means of computer simulations that there is a key parameter, which we define as the growth number that characterizes the ... | 2004 | 15363934 |
| expression of vip1/vip2 genes in escherichia coli and bacillus thuringiensis and the analysis of their signal peptides. | to determine the expression time courses and high expression level of vip2a(c) and vip1a(c) in bacillus thuringiensis, and survey their insecticidal toxicity and insecticidal spectrum. | 2004 | 15357725 |
| effects of plants genetically modified for insect resistance on nontarget organisms. | insect resistance, based on bacillus thuringiensis (bt) endotoxins, is the second most widely used trait (after herbicide resistance) in commercial genetically modified (gm) crops. other modifications for insect resistance, such as proteinase inhibitors and lectins, are also being used in many experimental crops. the extensive testing on nontarget plant-feeding insects and beneficial species that has accompanied the long-term and wide-scale use of bt plants has not detected significant adverse e ... | 2005 | 15355241 |
| the evolution of cotton pest management practices in china. | the development of cotton pest management practices in china has followed a pattern seen for many crops that rely heavily on insecticides. helicoverpa armigera resistance to chemical pesticides resulted in the unprecedented pest densities of the early 1990s. transgenic cotton that expresses a gene derived from the bacterium bacillus thuringiensis (bt) has been deployed for combating h. armigera since 1997. the pest management tactics associated with bt cotton have resulted in a drastic reduction ... | 2005 | 15355239 |
| binding analyses of cry1ab and cry1ac with membrane vesicles from bacillus thuringiensis-resistant and -susceptible ostrinia nubilalis. | the binding properties of bacillus thuringiensis toxins to brush border membrane vesicles of dipel-resistant and -susceptible ostrinia nubilalis larvae were compared using ligand-toxin immunoblot analysis, surface plasmon resonance (spr), and radiolabeled toxin binding assays. in ligand-toxin immunoblot analysis, the number of cry1ab or cry1ac toxin binding proteins and the relative toxin binding intensity were similar in vesicles from resistant and susceptible larvae. surface plasmon resonance ... | 2004 | 15351700 |
| laboratory and field evaluation of teknar hp-d, a biolarvicidal formulation of bacillus thuringiensis ssp. israelensis, against mosquito vectors. | larvicidal efficacy of teknar hp-d, an improved biolarvicidal formulation of bacillus thuringiensis ssp. israelensis (bti), against anopheles stephensi, culex quinquefasciatus and aedes aegypti was determined in the laboratory, and in field the efficacy of the formulation was tested against cx. quinquefasciatus breeding in cesspits, unused wells and drains. the toxicity of the formulation to gambusia affinis (larvivorous fish), notonecta sp. and diplonychus indicus (water bugs) was also evaluate ... | 2004 | 15350862 |
| patch-clamp study of the apical membrane of the midgut of manduca sexta larvae: direct demonstration of endogenous channels and effect of a bacillus thuringiensis toxin. | the patch-clamp technique was applied to the apical membrane of epithelial midgut cells of a lepidoptera, manduca sexta l. access to the apical membrane, the main target site of bacillus thuringiensis (bt) toxins, was achieved by using freshly isolated larval midgut preparations mounted onto holding glass pipettes. the epithelial cells retained their functional integrity, as evidenced by the magnitude of intracellular potentials recorded with microelectrodes. with standard 32 mm k(+) solution in ... | 2004 | 15350500 |
| genome update: promoter profiles. | 2004 | 15347738 | |
| [transformation of bt-cpti fusion protein gene to cabbage (brassica oleracea var. capitata) mediated by agrobacterium tumefaciens and particle bombardment]. | bt-cpti fusion protein gene was transferred to the explants of hypocotyl, cotyledon with petiole and shoot apex of cabbage (brassica oleracea l. var. capitata) variety "zhonggan no 8" via agrobacterium tumefaciens and particle bombardment, and 13 kanamycin-resistant plants were obtained. pcr and southern blotting hybridization verified that all these plants of the kanr plants of type i regenerated from hypocotyl and cotyledon with petiole mediated by a. tumefaciens were transgenic plants, 2 karr ... | 2002 | 15344329 |
| [transferring of multiple insect-resisting genes into two-line genetic male sterile rice pei'ai 64s by particle bombardment]. | transformation of two-line genetic male sterile indica rice variety pei'ai 64s was conducted by particle bombardment. three insect-resisting genes ligased into plasmid vector pkc-3 was introduced into calli derived from mature embryo and a total of 33 transgenic plants had been obtained. the pcr and southern blot analysis of each different gene in r0 plants and also pcr analysis of each different gene in r1 plants showed the integration of three insect-resisting genes into the genome of transgen ... | 2002 | 15344316 |
| impact of ecological factors on the initial invasion of bt transgenes into wild populations of birdseed rape (brassica rapa). | the inevitable escape of transgenic pollen from cultivated fields will lead to the emergence of transgenic crop-wild plant hybrids in natural patches of wild plants. the fate of these hybrids and that of the transgene depend on their ability to compete with their wild relatives. here we study ecological factors that may enhance the fitness of genetically modified hybrids relative to wild plants for a bacillus thuringiensis ( bt) transgene conferring resistance to insects. mixed stands of wild pl ... | 2004 | 15340690 |
| new qualitative detection methods of genetically modified potatoes. | in japan, 8 lines of genetically modified (gm) potato (2 lines of newleaf potato; nl, 3 lines of newleaf plus potato; nlp, and 3 lines of newleaf y potato; nly) have already been authorized as safe for use in foods and feeds. we have developed polymerase chain reaction (pcr) methods for the qualitative detection of the gm potatoes for the screening and the identification of nl, nlp and nly. the gene encoding uridine diphosphate (udp)-glucose pyrophosphorylase (ugpase) was used as a taxon specifi ... | 2004 | 15340215 |
| transgenic insect-resistant corn affects the fourth trophic level: effects of bacillus thuringiensis-corn on the facultative hyperparasitoid tetrastichus howardi. | as hyperparasitoids may have a considerable influence on the control of herbivorous arthropods, analyzing the host-mediated impact of bacillus thuringiensis-plants ("bt-plants") on hyperparasitoids is of interest. laboratory-scale experiments were conducted in order to assess the potential effect of bt-corn leaf material on the facultative hyperparasitoid tetrastichus howardi (olliff) (hymenoptera: eulophidae), mediated through the herbivore chilo partellus swinhoe (lepidoptera: crambidae) and i ... | 2004 | 15338032 |
| cloning, sequencing, and sequence analysis of two novel plasmids from the thermophilic anaerobic bacterium anaerocellum thermophilum. | the nucleotide sequence of two novel plasmids isolated from the extreme thermophilic anaerobic bacterium anaerocellum thermophilum dsm6725 (a. thermophilum), growing optimally at 70 degrees c, has been determined. pbas2 was found to be a 3653 bp plasmid with a gc content of 43%, and the sequence revealed 10 open reading frames (orfs). the two largest of these, namely orf21 and orf41, showed similarity to a bacillus plasmid recombinase and a pseudoalteromonas plasmid replication protein, respecti ... | 2004 | 15336490 |
| lethality of chlorine, chlorine dioxide, and a commercial fruit and vegetable sanitizer to vegetative cells and spores of bacillus cereus and spores of bacillus thuringiensis. | chlorine, clo2, and a commercial raw fruit and vegetable sanitizer were evaluated for their effectiveness in killing vegetative cells and spores of bacillus cereus and spores of bacillus thuringiensis. the ultimate goal was to use one or both species as a potential surrogate(s) for bacillus anthracis in studies that focus on determining the efficacy of sanitizers in killing the pathogen on food contact surfaces and foods. treatment with alkaline (ph 10.5 to 11.0) clo2 (200 microg/ml) produced by ... | 2004 | 15330537 |
| micropatterns of spores displaying heterologous proteins. | micropatterns of bacillus thuringiensis spores were generated by a combination of surface chemistry, microcontact printing, and spore surface display technique. the outermost layers of b. thuringiensis spores were engineered to present enhanced green fluorescent protein (egfp), and the biospecific interaction between biotin and streptavidin was utilized to spatially direct the egfp-presenting spores onto the micropatterned surfaces. the viability of the micropatterned spores was confirmed by the ... | 2004 | 15327288 |
| [characterization of resistant cell line of trichoplusia ni to bacillus thuringiensis toxin cry1ac]. | the cell line (bti-tn-5b1-4) of trichoplusia ni had been selected by bacilllus thuringiensis (bt) toxin cry1ac for 86 generations continuously. a high level of resistance was achieved and the partial characterizations of the resistance-selected bti-tn-5b1-4 cells were studied in order to explore the mechanism of the resistance to bt toxin. the cells selected by cry1ac had low level of cross-resistance (19.7 fold) to cry1c, their ability of tolerance in the hypotonic solution increased evidently ... | 2004 | 15323422 |
| population structure of the bacillus cereus group as determined by sequence analysis of six housekeeping genes and the plcr gene. | the population structure of the bacillus cereus group (52 strains of b. anthracis, b. cereus, and b. thuringiensis) was investigated by sequencing seven gene fragments (rpob, gyrb, pyca, mdh, mbl, muts, and plcr). most of the strains were classifiable into two large subgroups in six housekeeping gene trees but not in the plcr tree. in addition, several consistent clusters were identified, which were unrelated to species distinction. moreover, interrelationships among these clusters were incongru ... | 2004 | 15322020 |
| the bacillus thuringiensis phage gil01 encodes two enzymes with peptidoglycan hydrolase activity. | bacteriophage gil01, infecting bacillus thuringiensis serovar israelensis, possesses a linear dsdna genome of 14,931 bp with proteins attached to its 5' extremities and terminal inverted repeats at both ends. viral particles are sensitive to organic solvents, suggesting that a lipid membrane is present in the capsid. all these characteristics are reminiscent of those found in members of the tectiviridae family. sequence analysis of gil01 revealed the presence of two open reading frames (orf25 an ... | 2004 | 15321675 |
| mutations in the bacillus thuringiensis cry1ca toxin demonstrate the role of domains ii and iii in specificity towards spodoptera exigua larvae. | several mutants of the bacillus thuringiensis cry1ca toxin affected with regard to specific activity towards spodoptera exigua were studied. alanine was used to replace single residues in loops 2 and 3 of domain ii (mutant ppb19) and to replace residues 541-544 in domain iii (mutant ppb20). additionally, a cry1ca mutant combining all mutations was constructed (mutant ppb21). toxicity assays showed a marked decrease in toxicity against s. exigua for all mutants, while they retained their activity ... | 2004 | 15320864 |
| [response of parasitic wasps of cotton bollworm to different cotton varieties with transgenic bacillus thringienthsis genes]. | the relationship between the parasitic wasp population number of cotton bollworm (helicoverpa armigera) and the varieties of cotton was studied by releasing and collecting the eggs and larvae of cotton bollworm on transgenic and non-transgenic cottons. the research results from 2000 to 2003 showed that the parasitic rates of the eggs and larvae of cotton bollworm were notably lower in transgenic cotton field than in non-transgenic cotton field. at the same time, the effect of transgenic and non- ... | 2004 | 15320406 |
| green fluorescent protein quantification in whole plants. | as future biotechnology applications utilize recombinant proteins as commercial products, nondestructive assays will be necessary to determine protein concentrations accurately within plant tissues. green fluorescent protein (gfp) has been proposed as a potential marker for the monitoring of transgenic plants and quantifying recombinant protein levels under field conditions. this chapter discusses the utility of using gfp fluorescence as an indicator of protein concentrations and the methods use ... | 2005 | 15310924 |
| genetics of spinosad resistance in a multi-resistant field-selected population of plutella xylostella. | resistance to the bacteria-derived insecticides spinosad (conserve), abamectin (vertimec), bacillus thuringiensis var kurstaki (btk) (dipel), b thuringiensis var aizawai (bta) (xentari), b thuringiensis crystal endotoxins cry1ac and cry1ca, and to the synthetic insecticide fipronil was estimated in a freshly-collected field population (ch1 strain) of plutella xylostella (l) from the cameron highlands, malaysia. laboratory bioassays at g1 indicated significant levels of resistance to spinosad, ab ... | 2004 | 15307676 |
| activity of bacillus thuringiensis toxins against cocoa pod borer larvae. | twelve cry proteins from bacillus thuringiensis berliner were tested in bioassays on cacao plantations in indonesia for activity against the larvae of cocoa pod borer (conopomorpha cramerella (snellen)), an insect pest of the cacao tree. through the damage caused by their feeding, the larvae of cocoa pod borer cause the pods of the cocoa tree to ripen prematurely. they are difficult to control with conventional measures. preliminary assays identified five toxins that were more active than others ... | 2004 | 15307664 |
| competition of bacillus thuringiensis cry1 toxins for midgut binding sites: a basis for the development and management of transgenic tropical maize resistant to several stemborers. | binding and competition of five bacillus thuringiensis toxins--cry1ab, cry1ac, cry1ba, cry1ca, and cry1ea--for midgut binding sites from three pests, spodoptera frugiperda, diatraea saccharalis, and diatraea grandiosella, were investigated as part of a strategy to develop tropical transgenic maize resistant to several stemborers. on s. frugiperda, cry1ab and cry1ac compete for the same binding site; cry1ba and cry1ca compete for a second binding site. cry1ea recognizes a third specific binding s ... | 2004 | 15297925 |
| use of 16s rrna, 23s rrna, and gyrb gene sequence analysis to determine phylogenetic relationships of bacillus cereus group microorganisms. | in order to determine if variations in rrna sequence could be used for discrimination of the members of the bacillus cereus group, we analyzed 183 16s rrna and 74 23s rrna sequences for all species in the b. cereus group. we also analyzed 30 gyrb sequences for b. cereus group strains with published 16s rrna sequences. our findings indicated that the three most common species of the b. cereus group, b. cereus, bacillus thuringiensis, and bacillus mycoides, were each heterogeneous in all three gen ... | 2004 | 15297521 |
| mics of selected antibiotics for bacillus anthracis, bacillus cereus, bacillus thuringiensis, and bacillus mycoides from a range of clinical and environmental sources as determined by the etest. | this paper presents etest determinations of mics of selected antimicrobial agents for 76 isolates of bacillus anthracis chosen for their diverse histories and 67, 12, and 4 cultures, respectively, of its close relatives b. cereus, b. thuringiensis, and b. mycoides derived from a range of clinical and environmental sources. nccls breakpoints are now available for b. anthracis and ciprofloxacin, penicillin, and tetracycline; based on these breakpoints, the b. anthracis isolates were all fully susc ... | 2004 | 15297508 |
| evaluation of sampling plans to detect cry9c protein in corn flour and meal. | starlink is a genetically modified corn that produces an insecticidal protein, cry9c. studies were conducted to determine the variability and cry9c distribution among sample test results when cry9c protein was estimated in a bulk lot of corn flour and meal. emphasis was placed on measuring sampling and analytical variances associated with each step of the test procedure used to measure cry9c in corn flour and meal. two commercially available enzyme-linked immunosorbent assay kits were used: one ... | 2004 | 15295890 |
| signal peptide of potato pinii enhances the expression of cry1ac in transgenic tobacco. | the modified cry1ac was expressed in transgenic tobacco plants. to allow secretion of the cry1ac protein into the intercellular space, the signal peptide sequence of potato proteinase inhibitor ii (pinii) was n-terminally fused to the cry1ac encoding region. expression of cry1ac in transgenic tobacco plants was assayed with elisa. the results showed that pinii signal peptide sequence enhanced the expression of cry1ac protein and led to the secretion of the cry1ac protein in transgenic tobacco pl ... | 2004 | 15295648 |
| binary toxins from bacillus thuringiensis active against the western corn rootworm, diabrotica virgifera virgifera leconte. | the western corn rootworm, diabrotica virgifera virgifera leconte, is a significant pest of corn in the united states. the development of transgenic corn hybrids resistant to rootworm feeding damage depends on the identification of genes encoding insecticidal proteins toxic to rootworm larvae. in this study, a bioassay screen was used to identify several isolates of the bacterium bacillus thuringiensis active against rootworm. these bacterial isolates each produce distinct crystal proteins with ... | 2004 | 15294828 |
| characterization of two bacillus thuringiensis genes identified by in vivo screening of virulence factors. | bacillus thuringiensis vegetative cells are known to be highly pathogenic when injected into the hemocoel of susceptible insect larvae. this pathogenicity is due to the capacity of b. thuringiensis to cause septicemia in the host. we screened a b. thuringiensis mini-tn10 insertion library for loss of virulence against bombyx mori larvae on injection into the hemocoel. three clones with attenuated virulence were isolated, corresponding to two different mini-tn10 insertions mapping to the yqgb/yqf ... | 2004 | 15294815 |
| characterization of a novel plasma membrane protein, expressed in the midgut epithelia of bombyx mori, that binds to cry1a toxins. | we describe the properties of a novel 252-kda protein (p252) isolated from brush border membranes of bombyx mori. p252 was found in a triton x-100-soluble brush border membrane vesicle fraction, suggesting that it may be a component of the midgut epithelial cell membrane. p252 was purified to homogeneity, and the amino acid sequence of two internal peptides was determined, but neither of the peptides matched protein sequences in the available databases. the apparent molecular mass of the purifie ... | 2004 | 15294792 |
| a rapid screening method for the detection of viable spores in powder using bioluminescence. | a rapid diagnosis of a biological threat in a powder sample is important for fi rst responders who have to make decisions on-site. the present culture-based method does not provide timely results, which is a critical barrier for a quick response when a suspicious powder sample is found. the atp bioluminescence method, combined with a heat shock, was investigated to determine the presence of spores in powder. the results show that only spore-containing powder samples provided a dramatic increase ... | 2004 | 15287006 |
| development and mechanisms of resistance to bacillus thuringiensis endotoxin cry1ac in the american bollworm, helicoverpa armigera (hübner). | the american bollworm, h. armigera, evolved 31-fold resistance to selection pressure of b. thuringiensis endotoxin cry1ac within six generations. the cry1ac selected larvae of h. armigera showed cross-resistance to cry1aa and cry1ab both in terms of mortality and growth reduction. studies on mechanisms of resistance to cry1ac showed that proteases of resistant insects degraded cry1ac faster than those of susceptible insects, which led to the relative unavailability of toxin of about 58 kda for b ... | 2004 | 15282949 |
| potentiation of insecticidal activity of bacillus thuringiensis subsp. kurstaki hd-1 by proteinase inhibitors in the american bollworm, helicoverpa armigera (hübner). | the effect of crude proteinase inhibitor extracts from seeds of different crop plants (black gram, chickpea, chickling vetch, finger millet, french bean, green gram, horse gram, lentil, pea and soybean) on the insecticidal activity of b. thuringiensis var. kurstaki hd-1 was investigated against neonate larvae of h. armigera by diet incorporation method. the larval mortality due to crude proteinase inhibitors alone (5% seed weight equivalent) ranged from 4.1 to 19.1%; the maximum mortality with f ... | 2004 | 15282948 |
| cloning and partial characterization of zwittermicin a resistance gene cluster from bacillus thuringiensis subsp. kurstaki strain hd1. | the study seeks to shed light on the aminopolyol, broad-spectrum antibiotic zwittermicin a gene cluster of bacillus thuringiensis subsp. kurstaki hd1 and to identify any new uncharacterized genes with an eventual goal to establish a better understanding of the resistance gene cluster. | 2004 | 15281929 |
| genetics of resistance to transgenic bacillus thuringiensis poplars in chrysomela tremulae (coleoptera: chrysomelidae). | the area under genetically engineered plants producing bacillus thuringiensis (bt) toxins is steadily increasing. this increase has magnified the risk of alleles conferring resistance to these toxins being selected in natural populations of target insect pests. the speed at which this selection is likely to occur depends on the genetic characteristics of bt resistance. we selected a strain of the beetle chrysomela tremulae fabricius on a transgenic bt poplar clone populus tremula l. x populus tr ... | 2004 | 15279291 |
| cross-resistance of cry1ab-selected ostrinia nubilalis (lepidoptera: crambidae) to bacillus thuringiensis delta-endotoxins. | corn plants expressing the toxin from bacillus thuringiensis (berliner) have proven to be effective in controlling lepidopteran pests such as the european corn borer, ostrinia nubilalis (hübner) (lepidoptera: crambidae). several bt toxins are being tested and incorporated into crop genomes, although tests for cross-resistance among different toxins have been limited by a lack of resistant colonies. four different colonies of o. nubilalis selected with full-length cry1ab incorporated into artific ... | 2004 | 15279290 |
| role of egg density on establishment and plant-to-plant movement by western corn rootworm larvae (coleoptera: chrysomelidae). | the effect of egg density on establishment and dispersal of larvae of the western corn rootworm, diabrotica virgifera virgifera leconte, was evaluated in a 3-yr field study. implications of these data for resistance management plans for bt crops are discussed. viable egg levels of 100, 200, 400, 800, and 1600 eggs per infested plant were evaluated in 2000, 2001, and 2002. a 3200 viable egg level was also tested in 2001 and 2002. all eggs were infested on one plant per subplot in a field that was ... | 2004 | 15279266 |
| two new bacterial pathogens of colorado potato beetle coleoptera: chrysomelidae). | other than bacillus thuringiensis berliner, few bacteria are lethal to the colorado potato beetle (leptinotarsa decemlineata [say]), a major pest of potatoes and eggplant. expanded use of biologicals for the control of colorado potato beetle will improve resistance management, reduce pesticide use, and produce novel compounds for potential use in transgenic plants. using freeze-dried, rehydrated artificial diet in pellet form to screen bacteria lethal to other insects, we determined that strains ... | 2004 | 15279252 |
| shared genetic basis of resistance to bt toxin cry1ac in independent strains of pink bollworm. | classical and molecular genetic analyses show that two independently derived resistant strains of pink bollworm, pectinophora gossypiella (saunders), share a genetic locus at which three mutant alleles confer resistance to bacillus thuringiensis (bt) toxin cry1ac. one laboratory-selected resistant strain (azp-r) was derived from individuals collected in 1997 from 10 arizona cotton fields, whereas the other (aphis-98r) was derived from a long-term susceptible laboratory strain. both strains were ... | 2004 | 15279243 |
| microbial control of mosquitoes: management of the upper rhine mosquito population as a model programme. | for more than a decade, bacillus thuringiensis israelensis (bti) and b. sphaericus have been used successfully as biological control agents against mosquitoes in germany. over 1000 km(2) of breeding areas have been treated with bti, resulting in a yearly reduction of the mosquito population by more than 90%, without evidence of any harmful impact on the environment. here, norbert becker describes the control strategy and operational use of bti and b. sphaericus in germany. | 1997 | 15275138 |
| space spraying of bacterial and chemical insecticides against anopheles balabacensis baisas for the control of malaria in sabah, east malaysia. | a pilot study was undertaken to determine the effectiveness of space application of insecticides for the control of malaria in ranau, a district in sabah. a village each was treated monthly: with chemical adulticide--alpha cypermethrin (fendona sc(r)/10sc(r)) at 2 g a.i./10,000 m2 in pahu; with biological larvicides--bacillus thuringiensis israelensis (vectobac 12as(r)) at 500 ml/10,000 m2 or b. sphaericus (vectolex wg(r)) at 500 g/10,000 m2 in pinawantai; and with a mixture of chemical adultici ... | 2004 | 15272747 |
| two orthorhombic crystal structures of a galactose-specific lectin from artocarpus hirsuta in complex with methyl-alpha-d-galactose. | based on their carbohydrate specificity, the jacalin family of lectins can be divided into two groups: galactose-specific and mannose-specific. the former are cytoplasmic proteins, whereas the latter are localized in the storage vacuoles of cells. it has been proposed that the post-translational modification in some of the lectins that splits their polypeptide chains into two may be crucial for galactose specificity. the mannose-specific members of the family are single-chain proteins that lack ... | 2004 | 15272163 |
| intranasal coadministration of the cry1ac protoxin with amoebal lysates increases protection against naegleria fowleri meningoencephalitis. | cry1ac protoxin has potent mucosal and systemic adjuvant effects on antibody responses to proteins or polysaccharides. in this work, we examined whether cry1ac increased protective immunity against fatal naegleria fowleri infection in mice, which resembles human primary amoebic meningoencephalitis. higher immunoglobulin g (igg) than iga anti-n. fowleri responses were elicited in the serum and tracheopulmonary fluids of mice immunized by the intranasal or intraperitoneal route with n. fowleri lys ... | 2004 | 15271892 |
| delaying evolution of insect resistance to transgenic crops by decreasing dominance and heritability. | the refuge strategy is used widely for delaying evolution of insect resistance to transgenic crops that produce bacillus thuringiensis (bt) toxins. farmers grow refuges of host plants that do not produce bt toxins to promote survival of susceptible pests. many modelling studies predict that refuges will delay resistance longest if alleles conferring resistance are rare, most resistant adults mate with susceptible adults, and bt plants have sufficiently high toxin concentration to kill heterozygo ... | 2004 | 15271091 |
| cloning and nucleotide sequence of a novel cry gene from bacillus thuringiensis. | a cry1ab-type gene was cloned from a new isolate of bacillus thuringiensis by pcr. when restriction pattern was compared with that of known genes it was found to have additional restriction site for clai. nucleotide sequencing and homology search revealed that the toxin shared 95% homology with the known cry1ab proteins as compared to more than 98% homology among the other reported cry1ab toxins. the gene encoded a sequence of 1,177 amino acids compared to 1,155 amino acids encoded by all the ot ... | 2004 | 15266122 |
| characterization of a cry1ac-receptor alkaline phosphatase in susceptible and resistant heliothis virescens larvae. | we reported previously a direct correlation between reduced soybean agglutinin binding to 63- and 68-kda midgut glycoproteins and resistance to cry1ac toxin from bacillus thuringiensis in the tobacco budworm (heliothis virescens). in the present work we describe the identification of the 68-kda glycoprotein as a membrane-bound form of alkaline phosphatase we term hvalp. lectin blot analysis of hvalp revealed the existence of n-linked oligosaccharides containing terminal n-acetylgalactosamine req ... | 2004 | 15265032 |
| evaluation of calcium-alginate gel as an artificial diet medium for bioassays on common cutworms. | a calcium-alginate gel diet was developed for spodoptera litura larvae, and its reliability as a carrier for incorporating antifeedants as well as insecticides was investigated. the alginate gel diet was prepared with a simple protocol, which does not involve any heating process. when tested using this diet, acephate, a bacillus thuringiensis endotoxin formulation and rotenone reproducibly showed insecticidal activity against the larvae, while neem oil and scabequinone deterred the larval feedin ... | 2004 | 15264908 |
| effects of algae on the efficacy of bacillus thuringiensis var. israelensis against larval black flies. | personnel from several black fly control programs have reported that the efficacy of bacillus thuringiensis var. israelesis (bti) is reduced during periods when algal concentrations are high in the waterways. although the reduction in bti-induced mortality in black fly larvae is presumed to be related to the presence of algae, no scientific data support this theory. in this study, 4 genera of algae (microcytis, scenedesmus, dictrosphaerium, and chlorella) commonly detected in pennsylvania rivers ... | 2004 | 15264627 |
| influence of temperature and concentration of vectobac on control of the salt-marsh mosquito, ochlerotatus squamiger, in monterey county, california. | laboratory susceptibility bioassays were conducted to determine the efficacy of vectobac tp (bacillus thuringiensis var. israelensis [bti]) at different concentrations and temperatures against the salt-marsh mosquito ochlerotatus squamiger. bioassays on late 3rd- and early 4th-stage larvae, read at 72 h and 14 degrees c produced an ld90 of 0.223 mg/liter, whereas more than double this dose was required to produce similar mortality at 6 degrees c. a field trial in the winter of 2001-02 of an aeri ... | 2004 | 15264626 |
| comparative analysis of proteinase activities of bacillus thuringiensis-resistant and -susceptible ostrinia nubilalis (lepidoptera: crambidae). | proteinase activities were compared in soluble and membrane fractions of guts obtained from larvae of bacillus thuringiensis-resistant and -susceptible ostrinia nubilalis. overall, serine proteinases from soluble fractions of the susceptible strain were more active than those of the resistant strain. the soluble trypsin-like proteinase activity of the resistant strain was approximately half that of the susceptible strain. the number and relative molecular masses of soluble and membrane serine pr ... | 2004 | 15262280 |
| factors affecting the toxicity of bacillus thuringiensis var. israelensis and bacillus sphaericus to fourth instar larvae of chironomus tepperi (diptera: chironomidae). | laboratory bioassays (48h duration, 25+/-1 degrees c) were used to determine the toxicity of bacillus thuringiensis var. israelensis (b.t.i.) and bacillus sphaericus to fourth instar larvae of chironomus tepperi, a major pest of rice in southern australia. bioassays were conducted using different combinations of larval ages and densities to determine if these factors affected toxicity. the effects of temperature and substrate type on b.t.i. toxicity were also investigated. tests were conducted u ... | 2004 | 15261774 |
| changes in susceptibility to conventional insecticides of a cry1ac-selected population of helicoverpa armigera (hübner) (lepidoptera: noctuidae). | the changes in the susceptibility of the cotton bollworm, helicoverpa armigera (hübner) to three insecticides (lambda-cyhalothrin, phoxim and endosulfan) commonly used for control of this pest in china were monitored by bioassays at various generations. the insects were originally collected from bt cotton fields and selected with cry1ac over 44 generations. in comparison with a susceptible strain, the larval resistance of the bt-selected populations to cry1ac toxin increased 106-fold. simultaneo ... | 2004 | 15260299 |
| mitogen-activated protein kinase pathways defend against bacterial pore-forming toxins. | cytolytic pore-forming toxins are important for the virulence of many disease-causing bacteria. how target cells molecularly respond to these toxins and whether or not they can mount a defense are poorly understood. by using microarrays, we demonstrate that the nematode caenorhabditis elegans responds robustly to cry5b, a member of the pore-forming crystal toxin family made by bacillus thuringiensis. this genomic response is distinct from that seen with a different stressor, the heavy metal cadm ... | 2004 | 15256590 |
| expression of a modified cry1ie gene in e. coli and in transgenic tobacco confers resistance to corn borer. | the wild-type cry1ie gene from bacillus thuringiensis was modified for its efficient expression in transgenic plants. modified cry1ie gene (designated as cry1iem) was cloned into prokaryotic expression vector pet28b and its expression in e. coli was confirmed by sds-page analysis. bioassays using crude expression products in e. coli revealed that cry1iem protein had a similar toxicity to corn borer as wild-type cry1ie. cry1iem gene was then inserted downstream of the maize ubiquitin-1 promoter i ... | 2004 | 15253158 |
| cryptic endotoxic nature of bacillus thuringiensis cry1ab insecticidal crystal protein. | cry1ab is one of the most studied insecticidal proteins produced by bacillus thuringiensis during sporulation. structurally, this protoxin has been divided in two domains: the n-terminal toxin core and the c-terminal portion. although many studies have addressed the biochemical characteristics of the active toxin that corresponds to the n-terminal portion, there are just few reports studying the importance of the c-terminal part of the protoxin. herein, we show that cry1ab protoxin has a unique ... | 2004 | 15251434 |
| occurrence and significance of bacillus thuringiensis on wine grapes. | wine grapes harvested at different stages during cultivation from several vineyards in new south wales, australia, harboured bacillus thuringiensis at viable populations of 10(2)-10(6) cfu/g. commercial preparations of b. thuringiensis had been sprayed onto the grapes as a biological insecticide. b. thuringiensis (10(1)-10(3) cfu/ml) was isolated from grape juice and fermenting grape juice in a commercial winery. although b. thuringiensis remained viable when inoculated at 10(3)-10(4) cfu/ml int ... | 2004 | 15246241 |