Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| characterization of genetic diversity of some serovars of bacillus thuringiensis by rapd. | rapd based fingerprinting of 21 serovars of bacillus thuringiensis (bt) representing different serotypes was performed using 19 random decamer primers. a total of 172 polymorphic fragments, ranging in size from 161-2789 bp, were amplified from 13 of the 19 primers. pairwise genetic similarity analysis revealed very low similarity values, ranging from 3-68%, among the serovars of bt, indicating high genetic divergence. nineteen serovars of bt fell in two major clusters and remaining two formed so ... | 2001 | 11831372 |
| toxicity and synergism in transgenic escherichia coli expressing four genes from bacillus thuringiensis subsp. israelensis. | the genes cyt1aa and p20, encoding, respectively, cytolytic and accessory proteins of bacillus thuringiensis subsp. israelensis, were introduced into previously constructed clones expressing cry4aa and cry11aa in escherichia coli (ben-dov et al., 1995). fifteen clones with all possible combinations of the four genes were obtained and found to express the genes included. two new combinations, pve4-adrc and pve4-arc, expressing cyt1aa, p20 and cry4aa, with or without cry11aa, respectively, were mo ... | 2001 | 11846773 |
| determination of cry9c protein in corn-based foods by enzyme-linked immunosorbent assay: interlaboratory study. | the performance of a commercially available enzyme-linked immunosorbent assay kit (enviro-logix) was assessed for the determination of cry9c protein, which is produced by the genetically modified corn starlink, in 8 types of corn-based foods (starch, refined oil, soft tortillas, tortilla chips, corn flakes, corn puffs, corn muffins, and corn bread) in an interlaboratory study involving 7 laboratories in the united states. the assay kit is a double antibody sandwich and is based on the specific i ... | 2001 | 11767159 |
| engineered genes contaminate corn's birthplace. | 2001 | 11770775 | |
| [insecticidal activity of bacillus thuringiensis cells]. | the influence of sixteen different nutrient media on the entomopathogenic activity of three bacillus thuringiensis strains was studied. the medium composition based on potato, yeast extract, and molasses was optimized. b. thuringiensis no 1 grown on the media no 7 and 9 displayed the highest entomopathogenic activity (94.3 and 90.6%, respectively). | 2001 | 11771324 |
| [effect of chitosan oligomer on phage particles and reproduction of phage 1-97a in bacillus thuringiensis culture]. | the causes of bacteriophage 1-97a inactivation by the chitosan oligomer with a polymerization degree of 15 and the influence of the oligomer on the phage reproduction in the culture of bacillus thuringiensis subsp. galleriae, strain 1-97, were studied. the study of the inactivation kinetics showed that, in 1 h, virtually all chitosan was bound to the phage particles, causing, as evidenced by electron microscopy, dna release from the phage head, destruction of the phage particles, and agglutinati ... | 2001 | 11785139 |
| binding properties of bacillus thuringiensis cry4a toxin to the apical microvilli of larval midgut of culex pipiens. | cry4a is a dipteran-specific delta-endotoxin produced by bacillus thuringiensis, and toxic to culex pipiens (mosquito) larvae. the immunohistochemical staining of the midgut sections of c. pipiens larvae revealed that cry4a bound in vitro and in vivo to the microvilli of the epithelial cells of posterior midgut and gastric caecae. the binding of digoxigenin-labeled cry4a (dig-cry4a) to the apical microvilli was almost abolished in the presence of excess unlabeled cry4a, suggesting that the bindi ... | 2001 | 11791714 |
| effect of surface active agents on the production of biopesticides using wastewater sludge as a raw material. | effect of surface active agents on the production of bacillus thuringiensis based biopesticides using secondary wastewater sludge as a raw material was studied. the experiments were conducted in a shake flask and nine different commercial surface active agents were used at a concentration of 0.2% (v/v). the sludge samples after addition of surface active agents were sterilised at 121 degrees c for 30 min. the progress of biopesticide production was monitored by measuring viable cells and viable ... | 2001 | 11794662 |
| secondary effects of the pesticide bacillus thuringiensis kurstaki on chicks of spruce grouse (dendragapus canadensis). | the objective of this study was to determine if application of the biological pesticide bacillus thuringiensis kurstaki (b.t.k.) had secondary effects on spruce grouse (dendragapus canadensis) chicks in the southern boreal forest of ontario, canada. b.t.k. kills larvae of lepidoptera that might otherwise be food. this may affect types of food ingested and influence chick growth rates by reducing the availability of a high-protein food. amount of ingested grit, which is diet-dependent, may also b ... | 2001 | 11503075 |
| control of life, death, and differentiation in cultured midgut cells of the lepidopteran, heliothis virescens. | differentiated cells in the insect midgut depend on stem cells for renewal. we have immunologically identified integrin beta1, a promotor of cell-cell adhesion that also induces signals mediating proliferation, differentiation, and apoptosis on the surfaces of cultured heliothis virescens midgut cells; clusters of immunostained integrin beta1-like material, indicative of activated integrin, were detected on aggregating midgut columnar cells. growth factor-like peptides (midgut differentiation fa ... | 2001 | 11515966 |
| [studies on transgenic tobacco plants expressing two kinds of insect resistant genes]. | a synthetic bt cry1ac gene fussed with a secretary signal coding sequences at 5' end and a modified gna gene were used to construct a plant expression vector pbsgs1m+ and this vector was transferred into tobacco (nicotiana tabacum l.) by agrobacterium-mediated transformation method. results of pcr, southern blot and slot blot analysis indicated that both the chimeric bt cry1ac and gna genes were integrated into the genomes of transformed plants. western blot analysis indicated that at least the ... | 2001 | 11517599 |
| factors contributing to peak broadening and mass accuracy in the characterization of intact spores using matrix-assisted laser desorption/ionization coupled with time-of-flight mass spectrometry. | factors contributing to peak broadening, accuracy and precision in mass assignment in the matrix-assisted laser desorption/ionization characterization of a lipopeptide desorbed from intact bacillus spores were investigated. these spores were studied as an example of a thick, topologically irregular sample, which present a more difficult target than a pure peptide or protein. the type of matrix, matrix:sample ratio, laser fluence, and localized repetitive laser irradiation were all found to affec ... | 2001 | 11523093 |
| effect of bacillus thuringiensis cry1 toxins in insect hemolymph and their neurotoxicity in brain cells of lymantria dispar. | little information is available on the systemic effects of bacillus thuringiensis toxins in the hemocoel of insects. in order to test whether b. thuringiensis-activated toxins elicit a toxic response in the hemocoel, we measured the effect of intrahemocoelic injections of several cry1 toxins on the food intake, growth, and survival of lymantria dispar (lepidoptera) and neobellieria bullata (diptera) larvae. injection of cry1c was highly toxic to the lymantria larvae and resulted in the complete ... | 2001 | 11525986 |
| susceptibility of a field-derived, bacillus thuringiensis-resistant strain of diamondback moth to in vitro-activated cry1ac toxin. | resistant and susceptible populations of the diamondback moth (plutella xylostella) were tested with crystalline, solubilized, and partially and fully activated forms of the bacillus thuringiensis cry1ac delta-endotoxin. fully activated toxin greatly reduced the resistance ratio (ratio of the 50% lethal concentration for the resistant population to that for the susceptible population) of the resistant population, suggesting that a defect in toxin activation is a major resistance mechanism. | 2001 | 11526050 |
| illegal bt cotton in india haunts regulators. | 2001 | 11731762 | |
| transgenic dna introgressed into traditional maize landraces in oaxaca, mexico. | concerns have been raised about the potential effects of transgenic introductions on the genetic diversity of crop landraces and wild relatives in areas of crop origin and diversification, as this diversity is considered essential for global food security. direct effects on non-target species, and the possibility of unintentionally transferring traits of ecological relevance onto landraces and wild relatives have also been sources of concern. the degree of genetic connectivity between industrial ... | 2001 | 11734853 |
| drosophila toll is activated by gram-positive bacteria through a circulating peptidoglycan recognition protein. | microbial infection activates two distinct intracellular signalling cascades in the immune-responsive fat body of drosophila. gram-positive bacteria and fungi predominantly induce the toll signalling pathway, whereas gram-negative bacteria activate the imd pathway. loss-of-function mutants in either pathway reduce the resistance to corresponding infections. genetic screens have identified a range of genes involved in these intracellular signalling cascades, but how they are activated by microbia ... | 2001 | 11742401 |
| detection of specific bacillus anthracis spore biomarkers by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. | analysis by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (maldi-tofms) was applied for the characterization of bacillus anthracis spore biomarkers. b. anthracis spores were extracted under a simple procedure, followed by linear mode analysis, using sinapinic acid as the matrix. several markers with a mass range of 4-7 kda were detected in three b. anthracis strains: vollum, sterne and v770-np1-r. similar spectra were also obtained for spore extracts of two members ... | 2001 | 11746875 |
| study on the effect of bacillus thuringiensis (b.t. serotype h-14) and its toxins against cephalopina titillator (clark), the egyptian camel myiasis producing dipterous fly. | bacillus t. israelensis (b.t. serotype h-14) and its toxins have a marked lethal effect on both the eggs and the newly moulted 3rd stage larvae of cephalopina titillator. the bacillus was less effective than bacillus and its toxins on both the eggs and larvae. on the other hand, the larvae were more affected by both bacillus and bacillus and its toxins than the eggs. prolonged exposure time showed more lethal effect. | 2001 | 11775107 |
| effects of various insecticides on the development of the egg parasitoid trichogramma dendrolimi (hymenoptera: trichogrammatidae). | the toxicity of six insecticides, acephate, methomyl, ethofenprox, cartap, chlorfluazuron, and bacillus thuringiensis (bt) was tested on different developmental stages of the egg parasitoid, trichogramma dendrolimi (matsumura). each of the insecticides tested showed different degrees of toxicity to the parasitoid, ethofenprox showed the highest toxicity and cartap showed relatively higher toxicity compared with the other insecticides. the development of the parasitoids treated with these two ins ... | 2001 | 11777034 |
| interactions between nosema pyrausta (microsporidia: nosematidae) and bacillus thuringiensis subsp. kurstaki in the european corn borer (lepidoptera: pyralidae). | larval susceptibility to bacillus thuringiensis was determined for nosema pyrausta-infected and uninfected european corn borers, ostrinia nubilalis (hübner), in bioassays using a commercial formulation of b. thuringiensis subsp. kurstaki, dipel es, incorporated into diet. lc50 values for n. pyrausta-infected larvae were significantly lower (p<0.0001) than for uninfected larvae and declined with increasing levels of infection. lc50 values for a 15-d bioassay using field-colony first instars were ... | 2001 | 11777037 |
| dispersal of adult european corn borer (lepidoptera: crambidae) within and proximal to irrigated and non-irrigated corn. | the european corn borer, ostrinia nubilalis (hübner), causes economic damage to corn, zea mays l., throughout the corn belt. because this insect has become the primary target of bacillus thuringiensis berliner (bt) transgenic corn, current efforts addressing the management of o. nubilalis resistance to bt corn require information on adult european corn borer dispersal and factors affecting its dispersal. in 1998 we conducted mark-release-recapture, release-recapture, and caged-mating studies to ... | 2001 | 11777038 |
| bollworm (lepidoptera: noctuidae) survival on 'bollgard' and 'bollgard ii' cotton flower bud and flower components. | genetically modified cotton, gossypium hirsutum l., cultivars ('bollgard') that produce crystalline proteins from bacillus thuringiensis (berliner) are valuable tools for managing lepidopteran insect pests in the united states. however, high numbers of bollworm, helicoverpa zea (boddie), larvae have been observed feeding in white flowers of these cultivars. fresh tissue bioassays were conducted to investigate bollworm survival on bollgard and 'bollgard ii' cottons. bollworm survival was higher o ... | 2001 | 11777047 |
| different cross-resistance patterns in the diamondback moth (lepidoptera: plutellidae) resistant to bacillus thuringiensis toxin cry1c. | two strains of the diamondback moth, plutella xylostella (l.), were selected using cry1c protoxin and transgenic broccoli plants expressing a cry1c toxin of bacillus thuringiensis (bt). both strains were resistant to cry1c but had different cross-resistance patterns. we used 12 bt protoxins for cross-resistance tests, including cry1aa, cry1ab, cry1ac, cry1bb, cry1c, cry1d, cry1e, cry1f, cry1j, cry2ab, cry9aa, and cry9c. compared with the unselected sister strain (bcs), the resistance ratio (br) ... | 2001 | 11777062 |
| chronic exposure of the european corn borer (lepidoptera: crambidae) to cry1ab bacillus thuringiensis toxin. | transgenic corn expressing the insecticidal toxin from bacillus thuringiensis berliner is gaining support as an effective control technology for use against lepidopteran pests, particularly european corn borer, ostrinia nubilalis hübner (lepidoptera: crambidae). however, there is concern that widespread adoption of transgenic plants will rapidly lead to b. thuringiensis toxin resistance. thus, long-term selection of o. nubilalis populations with the cry1ab b. thuringiensis toxin has been underta ... | 2001 | 11777065 |
| fitness costs and maternal effects associated with resistance to transgenic cotton in the pink bollworm (lepidoptera: gelechiidae). | transgenic cotton producing a bacillus thuringiensis (bt) toxin is widely used for controlling the pink bollworm, perctinophora gossypiella (saunders). we compared performance of pink bollworm strains resistant to bt cotton with performance of their susceptible counterparts on non-bt cotton. we found fitness costs that reduced survival on non-bt cotton by an average of 51.5% in two resistant strains relative to the susceptible strains. the survival cost was recessive in one set of crosses betwee ... | 2001 | 11777066 |
| field efficacy and seasonal expression profiles for terminal leaves of single and double bacillus thuringiensis toxin cotton genotypes. | examination of commercial cry1ac transgenic bacillus thuringiensis berliner (bt) cotton varieties (bollgard, monsanto, st. louis, mo) and an experimental cry1ac + cry2ab transgenic bt cotton variety (bollgard ii, monsanto) for lepidopteran field efficacy was conducted during the 2000 growing season. in addition, a commercially available (envirologix, portland, me) quantification assay (elisa) was used to measure and profile the expression levels of cry proteins in two of these varieties ['dp50b, ... | 2001 | 11777069 |
| genetically modified feeds in animal nutrition. 1st communication: bacillus thuringiensis (bt) corn in poultry, pig and ruminant nutrition. | during the last few years, animal nutrition has been confronted with genetically modified organisms (gmo), and their significance will increase in the future. the study presents investigations on the substantial equivalence of the transgenic bt (bacillus thuringiensis) corn and the corresponding nontransgenic hybrid cesar and parameters of nutrition physiology such as digestibility and energy content for poultry, pigs and ruminants. the results of the analysed corn samples as well as of the sila ... | 2001 | 11865766 |
| the incompatibility between the plcr- and atxa-controlled regulons may have selected a nonsense mutation in bacillus anthracis. | bacillus anthracis, bacillus thuringiensis and bacillus cereus are members of the bacillus cereus group. these bacteria express virulence in diverse ways in mammals and insects. the pathogenic properties of b. cereus and b. thuringiensis in mammals results largely from the secretion of non-specific toxins, including haemolysins, the production of which depends upon a pleiotropic activator plcr. in b. anthracis, plcr is inactive because of a nonsense mutation in the plcr gene. this suggests that ... | 2001 | 11886551 |
| effect of sublethal concentration of bacillus thuringiensis var. kurstaki on food and developmental needs of the american bollworm, helicoverpa armigera (hübner). | effect of sublethal concentration of b. thuringiensis on the first, third, fourth and fifth instar larvae of the american bollworm, h. armigera was investigated to study their response to food consumption, digestion, utilization, and their development till adult formation. the young larvae surviving b. thuringiensis treatment in their first instar and third instar delayed larval period by two to three days, but did not consume more food as compared to control. however, they showed higher digesti ... | 2001 | 11906106 |
| a general strategy for identification of s-layer genes in the bacillus cereus group: molecular characterization of such a gene in bacillus thuringiensis subsp. galleriae nrrl 4045. | despite its possible role in virulence, there has been little molecular characterization of members of the s-layer protein family of the bacillus cereus group. it is hypothesized that the components of the s-layers are likely to display similar anchoring structures in bacillus thuringiensis and bacillus anthracis. based on inferred sequence similarities, a dna fragment encoding the cell-wall-anchoring domain of an s-layer component of bac: thuringiensis subsp. galleriae nrrl 4045 was isolated. t ... | 2001 | 11320137 |
| a new insertion sequence, is231m, in an autoagglutinable isolate of bacillus thuringiensis. | an insertion sequence was isolated from an autoagglutinable strain of bacillus thuringiensis. analysis of its dna sequence revealed high homology to the is231 family. the name is231m is proposed for this new insertion sequence. is231m is 1652 bp long and is delimited by two imperfect 20-bp inverted repeat sequences with two mismatches, which are flanked by two perfect 11-bp direct repeats (drs). the region upstream of the open reading frame, presumed to be able to form a stable hairpin structure ... | 2001 | 11322825 |
| role of alpha-helix seven of bacillus thuringiensis cry1ab delta-endotoxin in membrane insertion, structural stability, and ion channel activity. | domain i of the cry1ab insecticidal toxic protein has seven alpha-helices and is considered to be involved in the ion channel activity. while other alpha-helices, particularly alpha-4 and alpha-5, have been extensively explored, the remaining alpha-helices have been slightly studied. site-directed mutagenesis was used to generate mutations throughout sequences encoding the alpha-helix 7 to test its role in ion channel function. every amino acid residue in alpha-helix 7 was mutated to alanine. mo ... | 2001 | 11327876 |
| association of pcr and feeding bioassays as a large-scale method to screen tropical bacillus thuringiensis isolates for a cry constitution with higher insecticidal effect against spodoptera frugiperda (lepidoptera: noctuidae) larvae. | to verify whether the presence of any of the cry1c, 1d, 1e and 1f genes could be associated with high toxicity against fall armyworm. | 2001 | 11328507 |
| large-scale management of insect resistance to transgenic cotton in arizona: can transgenic insecticidal crops be sustained? | a major challenge for agriculture is management of insect resistance to toxins from bacillus thuringiensis (bt) produced by transgenic crops. here we describe how a large-scale program is being developed in arizona for management of resistance to bt cotton in the pink bollworm, pectinophora gossypiella (saunders) (lepidoptera: gelechiidae), and other insect pests of cotton. financial support from growers makes this program possible. collaboration between the arizona cotton research and protectio ... | 2001 | 11332820 |
| response of cotton to prebloom square loss. | in 1996 and 1997, various intensities of prebloom square removal were applied to three cultivars of cotton grown in mississippi. with the exception of one cultivar in 1997, all cultivars were b. thuringiensis (bt)-transgenic cotton. at harvest, the number of bolls and seed cotton weight was recorded for all plants in each square removal treatment. all cultivars responded similarly to square loss. a yield increase (overcompensation) was observed in the treatment where all squares were removed fro ... | 2001 | 11332830 |
| establishment of cry9c susceptibility baselines for european corn borer and southwestern corn borer (lepidoptera: crambidae). | in 1997 and 1998, cry9c susceptibility baselines were established for field-collected populations of european corn borer, osrinia nubilalis (hubner), and southwestern corn borer, diatraea grandiosella dyar. bioassay of neonate european corn borer larvae of 16 colonies collected from the midwestern united states indicated lc50 values ranging from 13.2 to 65.1 ng of cry9c protein per square centimeter. neonate european corn borer lc50 values ranged from 46.5 to 214 ng/cm2. neonate larvae of three ... | 2001 | 11332831 |
| treatment thresholds for stink bugs (hemiptera: pentatomidae) in cotton. | the green stink bug, acrosternum hilare (say), the southern green stink bug, nezara viridula (l), and the brown stink bug, euschistus servus (say), were predominant phytophagous pentatomidae detected during 1995-1997 in cotton in south carolina. these species occurred in similar numbers in conventional and transgenic cotton 'nucotn33b', containing the gene for expression of cryia(c) delta-endotoxin of bacillus thuringiensis berliner variety kurstaki. adult stink bugs moved into cotton from wild ... | 2001 | 11332832 |
| life history attributes of indian meal moth (lepidoptera: pyralidae) and angoumois grain moth (lepidoptera: gelechiidae) reared on transgenic corn kernels. | the indian meal moth, plodia interpunctella (hübner), and angoumois grain moth, sitotroga cerealella (olivier), are two globally distributed stored-grain pests. laboratory experiments were conducted to examine the impact that corn (zea mays l.) kernels (i.e., grain) of some bacillus thuringiensis berliner (bt) corn hybrids containing crylab bt delta-endotoxin have on life history attributes of indian meal moth and angoumois grain moth. stored grain is at risk to damage from indian meal moth and ... | 2001 | 11332858 |
| lipids of brush border membrane vesicles (bbmv) from plutella xylostella resistant and susceptible to cry1ac delta-endotoxin of bacillus thuringiensis. | plutella xylostella (px) that were 130000-fold more resistant to cry1ac were selected from the susceptible strain and maintained in the laboratory. the lc50 of the susceptible strain (pxs) was 0.38 microg toxin/g diet, whereas that of the resistant strain (pxr) was 4800 microg toxin/g diet. brush border membrane vesicles (bbmv) were prepared from both pxs and pxr. in ligand blot analysis, cry1ac bound to a 120-kda protein of bbmv; however, the intensity of the band was almost equal in both strai ... | 2001 | 11337261 |
| lipid-induced pore formation of the bacillus thuringiensis cry1aa insecticidal toxin. | after activation, bacillus thuringiensis (bt) insecticidal toxin forms pores in larval midgut epithelial cell membranes, leading to host death. although the crystal structure of the soluble form of cry1aa has been determined, the conformation of the pores and the mechanism of toxin interaction with and insertion into membranes are still not clear. here we show that cry1aa spontaneously inserts into lipid mono- and bilayer membranes of appropriate compositions. fourier transform infrared spectros ... | 2001 | 11337891 |
| thuricin 7: a novel bacteriocin produced by bacillus thuringiensis bmg1.7, a new strain isolated from soil. | detection and identification of new antagonistic activities towards bacillus cereus and relatives. | 2001 | 11298934 |
| immunological analysis of phloem sap of bacillus thuringiensis corn and of the nontarget herbivore rhopalosiphum padi (homoptera: aphididae) for the presence of cry1ab. | phloem sap of transgenic bacillus thuringiensis (bt) corn expressing a truncated form of the b. thuringiensis delta-endotoxin cry1ab, sap sucking aphids feeding on bt corn and their honeydew were analysed for presence of cry1ab using elisa. phloem sap of bt and non-bt corn was collected using a newly developed technique with a microcapillary being directly inserted into the phloem tubes. using this technique, no cry1ab was detected in the phloem sap. in contrast, measurable concentrations of cry ... | 2001 | 11298965 |
| isolation and partial characterization of gypsy moth btr-270, an anionic brush border membrane glycoconjugate that binds bacillus thuringiensis cry1a toxins with high affinity. | btr-270, a gypsy moth (lymantria dispar) brush border membrane molecule that binds bacillus thuringiensis (bt) cry1a toxins with high affinity, was purified by preparative gel electrophoresis. rabbit antibodies specific for the bt toxin-binding molecule were raised. attempts to label btr-270 by protein-directed techniques were futile, but it was degraded by proteases with broad specificity indicating the presence of a peptide. carbohydrate was detected by labeling with digoxigenin hydrazide foll ... | 2001 | 11304752 |
| update on the detection of beta-exotoxin in bacillus thuringiensis strains by hplc analysis. | the current work aimed to study the presence of beta-exotoxin by high-performance liquid chromatography (hplc) in supernatant fluids from final whole cultures of the 69 type strains and 13 subtypes of bacillus thuringiensis strains, as well as from some insecticidal strains. | 2001 | 11309078 |
| bacillus thuringiensis cry3ca1 protein is toxic to the colorado potato beetle, leptinotarsa decemlineata (say). | we expressed the wild-type cry3aa3 and cry3ca1 bacillus thuringiensis genes, which code for insecticidal proteins, in an escherichia coli expression system. highly purified preparations of the soluble delta-endotoxins were used to perform comparative bioassays with third-instar larvae of the colorado potato beetle (cpb). acute mortality data showed that cry3ca1 (ld(50) = 320.1 ng) was 2-fold more toxic than cry3aa3 (ld(50) = 672.9 ng). we also compared the chronic effects of sublethal doses of t ... | 2001 | 11312696 |
| a theoretical model of the tridimensional structure of bacillus thuringiensis subsp. medellin cry 11bb toxin deduced by homology modelling. | cry11bb is an insecticidal crystal protein produced by bacillus thuringiensis subsp. medellin during its stationary phase; this partial differential-endotoxin is active against dipteran insects and has great potential for mosquito borne disease control. here, we report the first theoretical model of the tridimensional structure of a cry11 toxin. the tridimensional structure of the cry11bb toxin was obtained by homology modelling on the structures of the cry1aa and cry3aa toxins. in this work we ... | 2001 | 11313644 |
| specificity of lectin activity of bacillus thuringiensis parasporal inclusion proteins. | sheep erythrocyte-agglutinating parasporal inclusion proteins from four bacillus thuringiensis strains (fitc-20, fitc-73, fitc-76 and ibc-1456) were examined for lectin activity against erythrocytes from four mammalian (rabbit, horse, cow and guinea pig) and an avian (chicken) species. of the five erythrocyte species, only rabbit cells were agglutinated with the protein of the human cancer cell-killing strain ibc-1456. no haemagglutination (ha) activities were shown in other protein-erythrocyte ... | 2001 | 11314244 |
| chitinase from bacillus thuringiensis subsp. pakistani. | the chitinase gene (chia71) from bacillus thuringiensis subsp. pakistani consists of an open reading frame of 1,905 nucleotides encoding 635 amino acid residues with an estimated molecular mass of 71 kda. comparison of the deduced amino acid sequence of the mature enzyme to other microbial chitinases shows a putative catalytic domain and a region with conserved amino acids similar to that of the type iii module of fibronectin and a chitin-binding domain. by activity detection of chitinase on sds ... | 2001 | 11549008 |
| screening for novel cry genes by hybridization. | to develop an efficient and sensitive method to facilitate the search for novel cry toxins. | 2001 | 11555212 |
| effects of exposure to event 176 bacillus thuringiensis corn pollen on monarch and black swallowtail caterpillars under field conditions. | the widespread planting of corn genetically modified to produce bacillus thuringiensis endotoxin has led to speculation that pollen from these fields might adversely affect nearby nontarget lepidopterans. a previous study of bt corn engineered with monsanto event 810 failed to detect an effect of pollen exposure on the black swallowtail, papilio polyxenes, in either the field or the laboratory. here, we report results of a field study investigating the impact of exposure to pollen from a bt corn ... | 2001 | 11559837 |
| temporal and spatial overlap between monarch larvae and corn pollen. | to assess the likelihood that monarch larvae will be exposed to bacillus thuringiensis (bt) pollen, we studied milkweed and monarch densities in habitats which comprise much of the land available to breeding monarchs, e.g., cornfields, cornfield edges, other agricultural fields, and nonagricultural areas, in four regions of the monarch breeding range. we found that monarchs use milkweed in cornfields throughout their breeding season, and that per plant densities are as high or higher in agricult ... | 2001 | 11559838 |
| assessing the impact of cry1ab-expressing corn pollen on monarch butterfly larvae in field studies. | survival and growth of monarch larvae, danaus plexippus (l.), after exposure to either cry1ab-expressing pollen from three bacillus thuringiensis (bt) corn (zea mays l.) events differing in toxin expression or to the insecticide, lambda-cyhalothrin, were examined in field studies. first instars exposed to low doses ( approximately 22 grains per cm(2)) of event-176 pollen gained 18% less weight than those exposed to bt11 or mon810 pollen after a 5-day exposure period. larvae exposed to 67 pollen ... | 2001 | 11559839 |
| corn pollen deposition on milkweeds in and near cornfields. | the density of corn pollen on leaves of milkweed plants inside and outside of cornfields was measured in several studies from different localities. the purpose was to obtain a representative picture of naturally occurring pollen densities to provide a perspective for laboratory and field studies of monarch larvae feeding on milkweed leaves with bt corn pollen. pollen density was highest (average 170.6 grains per cm(2)) inside the cornfield and was progressively lower from the field edge outward, ... | 2001 | 11559840 |
| monarch larvae sensitivity to bacillus thuringiensis- purified proteins and pollen. | laboratory tests were conducted to establish the relative toxicity of bacillus thuringiensis (bt) toxins and pollen from bt corn to monarch larvae. toxins tested included cry1ab, cry1ac, cry9c, and cry1f. three methods were used: (i) purified toxins incorporated into artificial diet, (ii) pollen collected from bt corn hybrids applied directly to milkweed leaf discs, and (iii) bt pollen contaminated with corn tassel material applied directly to milkweed leaf discs. bioassays of purified bt toxins ... | 2001 | 11559841 |
| impact of bt corn pollen on monarch butterfly populations: a risk assessment. | a collaborative research effort by scientists in several states and in canada has produced information to develop a formal risk assessment of the impact of bt corn on monarch butterfly (danaus plexippus) populations. information was sought on the acute toxic effects of bt corn pollen and the degree to which monarch larvae would be exposed to toxic amounts of bt pollen on its host plant, the common milkweed, asclepias syriaca, found in and around cornfields. expression of cry proteins, the active ... | 2001 | 11559842 |
| baseline susceptibility to bacterial insecticides in populations of culex pipiens complex (diptera: culicidae) from california and from the mediterranean island of cyprus. | bacterial insecticides play an increasingly important role in mosquito control. to establish guidelines for detecting resistance at an early stage, information on natural variation in susceptibility of insect populations to these insecticides is needed. between 1990 and 1993, the susceptibility of culex pipiens l. complex to bacillus thuringiensis subsp. israelensis de barjac and/or bacillus sphaericus neide was determined in 31 collections from california. these collections were undertaken befo ... | 2001 | 11561853 |
| overwintering cost associated with resistance to transgenic cotton in the pink bollworm (lepidoptera: gelechiidae). | fitness costs associated with resistance to transgenic crops producing toxins from bacillus thuringiensis (bt) may have important effects on the evolution of resistance. we investigated overwintering costs in pink bollworm, pectinophora gosypiella (saunders), strains with different degrees of resistance to bt cotton. frequency of resistant individuals in a strain was not associated with induction of diapause or emergence from diapause in early winter. emergence from diapause in the spring was 71 ... | 2001 | 11561855 |
| evaluation of a new tablet formulation based on bacillus thuringiensis sorovar. israelensis for larvicidal control of aedes aegypti. | the effect of sunlight on the efficacy and persistence of an experimental tablet formulation based on bacillus thuringiensis sorovar. israelensis (c4p1) was evaluated against aedes aegypti larvae under simulated field conditions. the initial mortality ranged from 93 to 100%, and the residual activity (> or = 70% mortality) recorded in containers exposed to sunlight or shade were, respectively, 13-35 days and 40-54 days. the results suggest that c4p1 can provide long-term larvicidal effect and op ... | 2001 | 11562715 |
| [production of stable bacillus thuringiensis suspensions in an electromagnetic apparatus]. | the experiment demonstrated the podibility of obtaining stable suspensions of b. subtilis, a microorganism used as an experimental model, in an electromagnetic apparatus with a bilateral inductor. the optimum conditions of obtaining such suspensions were chosen, these conditions excluding the inactivation of the bacteria used as a model in the course of the process. suspensions containing 75% of culture fluid were shown to have the highest stability during prolonged storage. suspensions on the b ... | 2001 | 11569272 |
| differential effects of ph on the pore-forming properties of bacillus thuringiensis insecticidal crystal toxins. | the effect of ph on the pore-forming ability of two bacillus thuringiensis toxins, cry1ac and cry1c, was examined with midgut brush border membrane vesicles isolated from the tobacco hornworm, manduca sexta, and a light-scattering assay. in the presence of cry1ac, membrane permeability remained high over the entire ph range tested (6.5 to 10.5) for kcl and tetramethylammonium chloride, but was much lower at ph 6.5 than at higher phs for potassium gluconate, sucrose, and raffinose. on the other h ... | 2001 | 11571147 |
| variation in susceptibility to bacillus thuringiensis toxins among unselected strains of plutella xylostella. | so far, the only insect that has evolved resistance in the field to bacillus thuringiensis toxins is the diamondback moth (plutella xylostella). documentation and analysis of resistant strains rely on comparisons with laboratory strains that have not been exposed to b. thuringiensis toxins. previously published reports show considerable variation among laboratories in responses of unselected laboratory strains to b. thuringiensis toxins. because different laboratories have used different unselec ... | 2001 | 11571163 |
| fluorescent amplified fragment length polymorphism analysis of norwegian bacillus cereus and bacillus thuringiensis soil isolates. | we examined 154 norwegian b. cereus and b. thuringiensis soil isolates (collected from five different locations), 8 b. cereus and 2 b. thuringiensis reference strains, and 2 bacillus anthracis strains by using fluorescent amplified fragment length polymorphism (aflp). we employed a novel fragment identification approach based on a hierarchical agglomerative clustering routine that identifies fragments in an automated fashion. no method is free of error, and we identified the major sources so tha ... | 2001 | 11571195 |
| isolation of bacillus thuringiensis from intertidal brackish sediments in mangroves. | intertidal brackish sediments in mangroves were examined for isolation of bacillus thuringiensis strains with novel toxicity spectra. a total of 18 b. thuringiensis isolates were recovered from eight sediment samples (36.4%) out of 22 samples tested. the frequency of b. thuringiensis was 1.3% among the colonies of bacillus cereus/b. thuringiensis group. while five isolates were allocated to the four h serogroups, the majority of the isolates were serologically untypable or untestable. two isolat ... | 2001 | 11572461 |
| the monarch butterfly controversy: scientific interpretations of a phenomenon. | the future development and use of agricultural biotechnology has been challenged by two preliminary studies indicating potential risk to monarch butterfly populations by pollen from corn engineered to express proteins from bacillus thuringiensis. likewise, these studies have also challenged the way in which science should be performed, published in scientific journals and communicated to the public at large. herein, we provide a history of the monarch controversy to date. we believe a retrospect ... | 2001 | 11576433 |
| development and commercial use of bollgard cotton in the usa--early promises versus today's reality. | bollgard cotton is the trademark given to a number of varieties of cotton bio-engineered to produce an insecticidal protein from bacillus thuringiensis (bt). when produced by the modified cotton plants, this protein controls certain lepidopterous cotton insect pests. commercially available since 1996, these cotton varieties are purchased under a license agreement in which the growers pay a fee and agree to abide by the terms, which include a 1-year license to use the technology and agreement to ... | 2001 | 11576434 |
| comparison of the omega-transaminases from different microorganisms and application to production of chiral amines. | microorganisms that are capable of (s)-enantioselective transamination of chiral amines were isolated from soil samples by selective enrichment using (s)-alpha-methyl-benzylamine ((s)-alpha-mba) as a sole nitrogen source. among them, klebsiella pneumoniae js2f, bacillus thuringiensis js64, and vibrio fluvialis js17 showed good omega-transaminase (omega-ta) activities and the properties of the omega-tas were investigated. the induction level of the enzyme was strongly dependent on the nitrogen so ... | 2001 | 11577718 |
| distribution of s-layers on the surface of bacillus cereus strains: phylogenetic origin and ecological pressure. | bacillus anthracis, bacillus cereus and bacillus thuringiensis have been described as members of the bacillus cereus group but are, in fact, one species. b. anthracis is a mammal pathogen, b. thuringiensis an entomopathogen and b. cereus a ubiquitous soil bacterium and an occasional human pathogen. in two clinical isolates of b. cereus, in some b. thuringiensis strains and in b. anthracis, an s-layer has been described. we investigated how the s-layer is distributed in b. cereus, and whether phy ... | 2001 | 11578310 |
| breaking the code of resistance. | 2001 | 11581654 | |
| [genetic analysis of cry1ab gene of bt rice]. | improved histochemical staining for gus activity, pcr and western blotting were used to analyse the progeny population of bt rice crossed with conventional rice varieties. a total of 392 plants expressing bt toxin protein were found in 394 gus positive plants. the result demonstrated that cry1ab gene closely inherited and expressed with reporter gene gus. gus assays indicated that cry1ab gene of bt rice inherits as a single dorminant gene. southern hybridization confirmed cry1ab gene can inherit ... | 2001 | 11582744 |
| evaluation of biological and chemical insecticide mixture against aedes aegypti larvae and adults by thermal fogging in singapore. | to improve the operational efficiency of dengue vector control in singapore, larvicide and adulticide were applied together by thermal fog generator (agrofog af40). the mixture consisted of bacillus thuringiensis var. israelensis (vectobac 12 as) as biological larvicide at 1.5 l/ha and pirimiphos-methyl (actellic 50 ec) as adulticide at 100 g ai/ha, diluted 10-fold with water. aerosol of this mixture was evaluated against the mosquito aedes aegypti (l.) (diptera: culicidae) in bioassays using ca ... | 2001 | 11583451 |
| processing of cry1ab delta-endotoxin from bacillus thuringiensis by manduca sexta and spodoptera frugiperda midgut proteases: role in protoxin activation and toxin inactivation. | activation of cry protoxins is carried out by midgut proteases. this process is important for toxicity and in some cases for specificity. commercial proteases have been used for in vitro protoxin activation. in the case of cry1a protoxins, trypsin digestion generates a toxic fragment of 60-65 kda. here, we have analyzed the in vitro and in vivo activation of cry1ab. we found differences in the processing of cry1ab protoxin by manduca sexta and spodoptera frugiperda midgut proteases as compared t ... | 2001 | 11583928 |
| allergenicity of cry9c: an unresolved issue. | 2001 | 11590402 | |
| bt breakthrough reveals good and bad news for pest resistance. | 2001 | 11642460 | |
| sample preparation for beta-exotoxin determination in bacillus thuringiensis cultures by reversed-phase high-performance liquid chromatography. | beta-exotoxin is a nucleotide analogue produced by the entomopathogenic bacterium bacillus thuringiensis. we have defined two new hplc procedures for quantification of this exotoxin in culture supernatants of b. thuringiensis grown in poor or rich medium. the sample is prepared either by precipitation in solvent or by solid-phase extraction. solvent precipitation is achieved treating the sample with acetone and acetonitrile. solid-phase extraction is performed with a c18 and an anion-exchange ca ... | 2001 | 11673902 |
| bt or not bt: is that the question? | 2001 | 11675483 | |
| regulation of the packaging of bacillus thuringiensis delta-endotoxins into inclusions. | during sporulation, many bacillus thuringiensis subspecies synthesize several related delta-endotoxins which are packaged into bipyramidal intracellular inclusions. these inclusions are solubilized in the alkaline, reducing conditions of the midguts of susceptible insect larvae and are converted by proteolysis to active toxins. the toxins insert into the membranes of cells lining the midgut and form cation-selective channels, which results in lethality. there are three delta-endotoxins, cry1ab3, ... | 2001 | 11679322 |
| high genetic variability for resistance to bacillus thuringiensis toxins in a single population of diamondback moth. | the long-term benefit of insecticidal products based on cry toxins, either in sprays or as transgenic crops, is threatened by the development of resistance by target pests. the models used to predict evolution of resistance to cry toxins most often are monogenic models in which two alleles are used. moreover, the high-dose/refuge strategy recommended for implementation with transgenic crops relies on the assumption that the resistance allele is recessive. using selection experiments, we demonstr ... | 2001 | 11679324 |
| bacillus thuringiensis delta-endotoxin cry1 hybrid proteins with increased activity against the colorado potato beetle. | cry1 delta-endotoxins of bacillus thuringiensis are generally active against lepidopteran insects, but cry1ba and cry1ia have additional, though low, levels of activity against coleopterans such as the colorado potato beetle. here we report the construction of cry1ba/cry1ia hybrid toxins which have increased activities against this insect species. | 2001 | 11679364 |
| predicting spring moth emergence in the pink bollworm (lepidoptera: gelechiidae): implications for managing resistance to transgenic cotton. | cultural control methods have been central in the southwestern united states for reducing pink bollworm, pectinophora gossypiella (saunders), damage to cotton. nevertheless, it is not clear at present how such methods could be integrated within the novel pest management framework allowed by introduction of cotton producing a toxin from bacillus thuringiensis (bt) for pink bollworm control. using statewide pheromone trapping and climatic data in conjunction with deterministic simulation models, w ... | 2001 | 11681660 |
| larval mortality and development of pseudoplusia includens (lepidoptera: noctuidae) reared on a transgenic bacillus thuringiensis-cotton cultivar expressing cryiac insecticidal protein. | the effects of a transgenic bacillus thuringiensis (bt)-cotton cultivar (dpl 32) on three instars of the soybean looper, pseudoplusia includens (walker), were determined in laboratory studies. first, third, and fifth instars were fed field collected bt-cotton leaves for 1, 2, four and 7 d or until pupation, and then transferred to artificial diet. mortality during the larval stage increased linearly in response to an increase in the length of feeding time on bt-cotton by first and third instars. ... | 2001 | 11681665 |
| biotic and abiotic factors limiting efficacy of bt corn in indirectly reducing mycotoxin levels in commercial fields. | incidence of insect damage, and association of insect damage with mycotoxigenic corn ear molds and mycotoxins was examined in commercial fields of bt and non-bt hybrids of different backgrounds in illinois in 1998 and 1999. nearly 50% helicoverpa zea (boddie) infestation sometimes occurred in bt hybrids that express high levels of the protein in silks and kernels. damage by european corn borer, ostrinia nubilalis hübner, was uncommon, even in non-bt ears. levels of total fumonisins were generall ... | 2001 | 11681667 |
| new tachinidae (diptera) host records of eastern north american forest canopy lepidoptera: baseline data in a bacillus thuriengiensis variety kurstaki nontarget study. | macrolepidopteran caterpillars collected in 1995 and 1996 in the monongahela national forest, pocahontas county, wv, and the george washington national forest, augusta county, va, yielded 60 previously unreported tachinid host associations. most associations were between native species, but the introduced polyphagous tachinid compsilura concinnata (meigen) produced eight new associations with native hosts. the tachinids collected were slightly broader in their host preferences than associated br ... | 2001 | 11681675 |
| variation in the susceptibility of the forest tent caterpillar (lepidoptera: lasiocampidae) to bacillus thuringiensis variety kurstaki hd-1: effect of the host plant. | host-mediated effect on the efficacy of bacillus thuringiensis berliner against larvae of the forest tent caterpillar. malacosoma disstria hübner, was investigated under controlled conditions. host plants used in this study were quaking aspen, populus tremuloides michx., a preferred host, and sugar maple, acer saccharum marsh., a secondary host. larvae were reared in the laboratory on leaves of these hosts, and upon reaching the third, fourth, and fifth instar, they were fed leaves treated with ... | 2001 | 11681676 |
| management of early-instar japanese beetle (coleoptera: searabaeidae) in field-grown nursery crops. | numerous field studies were conducted in commercial nurseries in tennessee from 1996 through 1999 to evaluate chemical and biological treatments, application timing and rates, and method of application for control of early instars of japanese beetle, popillia japonica newman. insecticide treatments included bifenthrin, bendiocarb, chlorpyrifos, carbaryl, fipronil, halofenozide, imidacloprid, permethrin, tefluthrin, thiamethoxam, and trichlorfon. biological treatments included entomopathogenic ne ... | 2001 | 11681678 |
| effects of bt cotton and crylac toxin on survival and development of pink bollworm (lepidoptera: gelechiidae). | we evaluated the effects of bacillus thuringiensis (bt) toxin crylac on survival and development of a susceptible strain and laboratory-selected resistant strains of pink bollworm, pectinophora gossypiella (saunders). for susceptible and resistant strains tested on artificial diet, increases in crylac concentration reduced developmental rate and pupal weight. in greenhouse tests, survival of resistant larvae on transgenic cotton that produces crylac (bt cotton) was 46% relative to their survival ... | 2001 | 11681689 |
| life history traits of helicoverpa zea (lepidoptera: noctuidae) on non-bt and bt transgenic corn hybrids in eastern north carolina. | transgenic varieties of field corn that express the crylab b. thuringiensis (bt) toxin in ear tissue present the potential of reducing ear feeding by the corn earworm, helicoverpa zea (lepidoptera: noctuidae), and for reducing the size of populations of the insect infesting other host crops. life history parameters of h. zea feeding on ears of conventional and bt field corn varieties were measured in field plots in eastern north carolina in 1997 and 1998. transformation events investigated were ... | 2001 | 11681693 |
| aminopeptidase-n from the helicoverpa armigera (hubner) brush border membrane vesicles as a receptor of bacillus thuringiensis crylac delta-endotoxin. | brush border membrane vesicles (bbmvs) were prepared from the 2nd instar larvae of helicoverpa armigera. binding of the activated cry1ac of bacillus thuringiensis (bt) toxin was shown by immunoblot. a 120-kda protein was identified as a receptor for the cry1ac type delta-endotoxin. the aminopeptidase-n activity of bbmvs was measured as the hydrolysis of l-leucine p-nitroanilide. the specific activity was 35 units/mg protein. the bbmv preparation also showed low level of alkaline phosphatase acti ... | 2001 | 11683359 |
| isolation and characterization of a bacillus thuringiensis ssp. kurstaki strain toxic to spodoptera exigua and culex pipiens. | a strain of bacillus thuringiensis with dual toxicity was isolated from korean soil samples and named k2. k2 was determined as ssp. kurstaki (h3a3b3c) by serological test and produced bipyramidal-shaped parasporal inclusions. the plasmid and protein profiles of b. thuringiensis k2 were different from those of the reference strain, ssp. kurstaki hd-1. to verify gene type of b. thuringiensis k2, pcr analysis with specific cry gene primers was performed. the result showed that b. thuringiensis k2 h ... | 2001 | 11683364 |
| identification of entomopathogenic bacillus isolated from simulium (diptera, simuliidae) larvae and adults. | entomopathogenic bacteria isolated from simulium larvae and adults from breeding sites in the states of são paulo and rio de janeiro, brazil, were identified as 18 strains of bacillus thuringiensis and one of b. sphaericus. most of these strains were serotyped according to their flagellar antigens. however, nine of the b. thuringiensis samples, could not be serotyped and were designated as "autoagglutinating"; they were also shown to be toxic in preliminary tests against aedes aegypti larvae. ad ... | 2001 | 11685272 |
| molecular cloning of a new crystal protein gene cry1af1 of bacillus thuringiensis nt0423 from korean sericultural farms. | a new cry1ab-type gene encoding the 130 kda protein of bacillus thuringiensis nt0423 bipyramidal crystals was cloned, sequenced, and expressed in a crystal-negative b. thuringiensis host. hybridization experiments revealed that the crystal protein gene is located on a 44 mda plasmid of b. thuringiensis nt0423. a strong positive signal detected on the 6.6 kb hindiii fragment from b. thuringiensis nt0423 plasmid dna was cloned and sequenced. the cry1ab-type gene, designated cry1af1, consisted of o ... | 2001 | 11685507 |
| bacteriological larvicides of dipteran disease vectors. | the apparent success in vector control observed between 1950 and 1970 was followed by worldwide resistance to organosynthetic insecticides wherever they were used intensively. insect resistance to one or more categories of insecticides has limited the effectiveness of these compounds, and their non-selective mode of action adversely affects non-target organisms. this scenario highlights the need for selective agents in integrated vector control programs. this article gives an overview of the mai ... | 2001 | 11685898 |
| ion channels induced in planar lipid bilayers by the bacillus thuringiensis toxin cry1aa in the presence of gypsy moth (lymantria dispar) brush border membrane. | the apical brush border membrane, the main target site of bacillus thuringiensis toxins, was isolated from gypsy moth (lymantria dispar) larval midguts and fused to artificial planar lipid bilayer membranes. under asymmetrical n-methyl-d-glucamine-hcl conditions (450 mm cis/150 mm trans, ph 9.0), which significantly reduce endogenous channel activity, trypsin-activated cry1aa, a b. thuringiensis insecticidal protein active against the gypsy moth in vivo, induced a large increase in bilayer membr ... | 2001 | 11687877 |
| effect of accessory proteins p19 and p20 on cytolytic activity of cyt1aa from bacillus thuringiensis subsp. israelensis in escherichia coli. | the gene coding for the accessory protein p19 of bacillus thuringiensis subsp. israelensis was expressed in escherichia coli and its product was characterized. to investigate its putative role in delta-endotoxin crystallization as a p20-like polypeptide, each of the two encoding genes, p20 and p19, was cloned for inducible expression coordinatively with cyt1aa. the latter is known to kill its transgenic host. p20 but not p19 stabilized cyt1aa and protected the host cells from its lethal effect. ... | 2001 | 11688801 |
| expression and crystallization of an n-terminally activated form of the bacillus thuringiensis cry1ca toxin. | when the active form of the bacillus thuringiensis delta-endotoxin cry1ca was expressed in e. coli severe growth retardation was observed. the absence of a short peptide from the n-terminus of the protoxin was responsible for this effect. the introduction of a mutation at an amino acid previously reported as being involved in the initial stages of pore formation within the natural insect target partially abolished the growth retardation effect. we suggest that removal of the n-terminal peptide i ... | 2001 | 11688803 |
| suitability of anabaena pcc7120 expressing mosquitocidal toxin genes from bacillus thuringiensis subsp. israelensis for biotechnological application. | we present evidence that anabaena pcc7120 (a.7120) strains expressing mosquitocidal toxin genes from bacillus thuringiensis subsp. israelensis (bti) have a strong potential for biotechnological application. characterization of two 4-year-old recombinant a.7120 clones constructed previously in our laboratory [clone 7 and clone 11, each carrying three bti genes (cry4aa, cry11aa, and p20)] revealed three facts. first, the bti genes were stable in a.7120 even in the absence of antibiotic selection w ... | 2001 | 11693914 |
| recombinant baculoviruses for insect control. | baculoviruses are double-stranded dna viruses which are highly selective for several insect groups. they are valuable natural control agents, but their utility in many agricultural applications has been limited by their slow speed of kill and narrow host specificity. baculoviruses have been genetically modified to express foreign genes under powerful promoters in order to accelerate their speed of kill. in our and other laboratories, the expression of genes coding for insect juvenile hormone est ... | 2001 | 11695193 |
| notes from the underground. communication and control in the rhizosphere. | 2001 | 11706157 | |
| structure of cry3a delta-endotoxin within phospholipid membranes. | interaction of delta-endotoxin and its proteolytic fragments with phospholipid vesicles was studied using electron microscopy, scanning microcalorimetry, and limited proteolysis. it was shown that native protein destroys liposomes. the removal of 4 n-terminal alpha-helices and the extreme 56 c-terminal amino acid residues did not affect this ability. the results obtained by limited proteolysis of delta-endotoxin bound to lipid vesicles show essential conformational changes in three or four n-ter ... | 2001 | 11714267 |
| crystallization of the bacillus thuringiensis toxin cry1ac and its complex with the receptor ligand n-acetyl-d-galactosamine. | cry1ac from bacillus thuringiensis ssp. kurstaki hd-73 is a pore-forming protein specifically toxic to lepidopteran insect larvae. it binds to the cell-surface receptor aminopeptidase n in manduca sexta midgut via the sugar n-acetyl-d-galactosamine (galnac). by using 1,3-diaminopropane (dap) as the buffer throughout protoxin activation and chromatography on q-sepharose at ph 10.3, trypsin-activated cry1ac has been purified in a monomeric state, which was crucial to obtaining single crystals of c ... | 2001 | 11717524 |