Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| [the formed toxin of bacillus thuringiensis. enzymatic production of toxic soluble substances by injection]. | 1962 | 14463346 | |
| protein turnover and the formation of protein inclusions during sporulation of bacillus thuringiensis. | 1961 | 14475423 | |
| serological studies on the formation of protein parasporal inclusions in bacillus thuringiensis. | a strain of bacillus thuringiensis has been isolated, and methods have been developed for separation of the crystalline, parasporal inclusions in a pure form. normal sporulation with concomitant crystal formation takes place when cells are incubated under suitable conditions in a nutrient free medium. serological techniques have been used to study the origin and development of the crystals. rabbit antisera have been prepared to a vegetative cell extract, suspensions of crystals, and a solution o ... | 1961 | 14475424 |
| insect resistance to transgenic bt crops: lessons from the laboratory and field. | transgenic crops that produce insecticidal toxins from the bacterium bacillus thuringiensis (bt) grew on >62 million ha worldwide from 1996 to 2002. despite expectations that pests would rapidly evolve resistance to such bt crops, increases in the frequency of resistance caused by exposure to bt crops in the field have not yet been documented. in laboratory and greenhouse tests, however, at least seven resistant laboratory strains of three pests (plutella xylostella [l.], pectinophora gossypiell ... | 2003 | 14503572 |
| novel fermentation media for production of bacillus thuringiensis subsp. israelensis. | the production of bacillus thuringiensis subsp. israelensis (debarjac) (bti) as a biopesticide is not cost-effective using existing fermentation technology. in this study, we explored the use of several less expensive alternative culture media (potato, common sugar, and bengal gram) for the growth and production of bti. growth was obtained in all tested media and was comparable to that obtained in conventional medium (luria-bertani). toxicity assays showed that the toxin produced from the novel ... | 2003 | 14503573 |
| resistance to the cry1ac delta-endotoxin of bacillus thuringiensis in the cotton bollworm, helicoverpa armigera (lepidoptera: noctuidae). | three laboratory strains of helicoverpa armigera (hübner) were established by mating of field-collected insects with an existing insecticide-susceptible laboratory strain. these strains were cultured on artificial diet containing the cry1ac protoxin of bacillus thuringiensis using three different protocols. when no response to selection was detected after 7-11 generations of selection, the three strains were combined by controlled mating to preserve genetic diversity. the composite strain (bx) w ... | 2003 | 14503603 |
| efficacy of transgenic cotton containing a cry1ac gene from bacillus thuringiensis against helicoverpa armigera (lepidoptera: noctuidae) in northern china. | nucotn 33b, a bt transgenic variety of upland cotton (gossypium hirsutum l.) expressing the insecticidal protein cry1ac from bacillus thuringiensis berliner sp. kurstaki, was evaluated for resistance to helicoverpa armigera (hübner) during 1998-2000 in northern china. the results indicated that there was no significant difference in egg densities between nucotn 33b and three nontransgenic varieties (dp5415, zhongmian12, and shiyuan321) during the season, although the survival of larvae on nucotn ... | 2003 | 14503607 |
| neural networks applied to the prediction of fed-batch fermentation kinetics of bacillus thuringiensis. | this paper proposes using a new recurrent neural network model (rnnm) to predict and control fed batch fermentations of bacillus thuringiensis. the control variables are the limiting substrate and the feeding conditions. the multi-input multi-output rnnm proposed has twelve inputs, seven outputs, nineteen neurons in the hidden layer, and global and local feedbacks. the weight update learning algorithm designed is a version of the well known backpropagation through time algorithm directed to the ... | 2003 | 14505001 |
| identification of novel bacillus thuringiensis cry1ac binding proteins in manduca sexta midgut through proteomic analysis. | the crystal proteins of bacillus thuringiensis are widely used in transgenic crops and commercially available insecticides. manduca sexta, the tobacco hornworm, is the model insect for b. thuringiensis studies. although brush border vesicles prepared from larval m. sexta midgut have been used in numerous mode-of-action studies of b. thuringiensis toxins, their protein components are mostly unknown. vesicles prepared from the brush border of m. sexta midgut were analyzed using one- and two-dimens ... | 2003 | 14505693 |
| recombinant bacteria for mosquito control. | bacterial insecticides have been used for the control of nuisance and vector mosquitoes for more than two decades. nevertheless, due primarily to their high cost and often only moderate efficacy, these insecticides remain of limited use in tropical countries where mosquito-borne diseases are prevalent. recently, however, recombinant dna techniques have been used to improve bacterial insecticide efficacy by markedly increasing the synthesis of mosquitocidal proteins and by enabling new endotoxin ... | 2003 | 14506223 |
| identification of a novel dna methyltransferase activity from bacillus thuringiensis. | a dna methyltransferase activity was identified in a strain of bacillus thuringiensis that was found to protect dna from cleavage by the restriction endonuclease haeiii at overlapping sites. site-directed mutagenesis was used to confirm therecognition sequence of the methyltransferase as acggc. | 2003 | 14506863 |
| pathogenicity of bacillus thuringiensis isolated from two species of acromyrmex (hymenoptera, formicidae). | the control of acromyrmex leaf-cutting ants is necessary due to the severe damage they cause to diverse crops. a possibility was to control them using the bacterium bacillus thuringiensis (bt) that characteristically produces insecticidal crystal proteins (icps). the icps have been effective in controlling lepidopterans, dipterans, and coleopterans, but their action against hymenopterans is unknown. this paper describes an attempt to isolate bt from ants of two acromyrmex species, to evaluate it ... | 2003 | 14509852 |
| enduring toxicity of transgenic anabaena pcc 7120 expressing mosquito larvicidal genes from bacillus thuringiensis ssp. israelensis. | persistence of biological control agents against mosquito larvae was tested under simulated field conditions. mosquito larvicidal activity of transgenic anabaena pcc 7120 expressing cry4aa, cry11aa and p20 from bacillus thuringiensis ssp. israelensis was greater than b. thuringiensis ssp. israelensis primary powder (fun 89c06d) or wettable powder (wp) (bactimos products) when either mixed with silt or exposed to sunlight outdoors. reduction of bactimos primary powder toxicity was at least 10-fol ... | 2003 | 14510853 |
| relocating expression of vegetative insecticidal protein into mother cell of bacillus thuringiensis. | vegetative insecticidal protein (vip) is a class of insecticidal proteins produced by some strains of bacillus thuringiensis during the vegetative stage of their growth. unlike delta-endotoxins which are produced as parasporal inclusion bodies within the cell during sporulation, vip is secreted into the culture medium. here we report the relocation of the expression of vip into the mother cell compartment in a manner similar to well-characterized cry proteins. relocation of vip is directed to mo ... | 2003 | 14511664 |
| epitope tagging: a monoclonal antibody specific for recombinant fusion proteins in plants. | the easy identification of a recombinant protein in plant material becomes increasingly relevant as more transgenic plants are used for research and commercial applications. tagging recombinant proteins with a small peptide (epitope) can perform such a task. however, available epitope antibodies will also cross-react with endogenous plant proteins at a level that may be unacceptable. here we describe the new epitope antibody acv5. whether it is attached to the carbooxyl terminal end of enhanced ... | 2003 | 14513553 |
| [the difficulty of obtaining immunologic responses in mucosae. use of coadjuvants]. | the search of immunogenicity represents a real problem to be solved with the new techniques to vaccines design. despite of numerous initiatives to increase the immune response at mucosal sites, there are few substances available to exert an adequate immunogenicity in mucosal compartments. on this hand the research on mucosal adjuvants has arise interest. mechanism of both: immunogenicity and adjuvanticity, were reviewed putting emphasis mainly in two mucosal adjuvants, cholera toxin and the prot ... | 2003 | 14513603 |
| characterization of a novel cry2aa-type gene from bacillus thuringiensis subsp. kurstaki. | a 4 kb bamhi-hindili fragment, corresponding to the cry2a operon of bacillus thuringiensis subsp. kurstaki strain bns3, was cloned. the sequencing of the corresponding cry2aa-type gene, termed crybns3-4, revealed an open reading frame of 1902 bp, encoding a protein of 633 amino-acid residues. both nucleotide and amino-acid sequences similarity analysis revealed that crybns3-4 is a new cry2aa-type gene which has several differences from the reported cry2aa-type genes. the transfer of the cloned o ... | 2003 | 14514070 |
| [inter- and intraspecies conjugal transfer of different plasmids in bacilli]. | conjugal transfer of plasmid pub110 between different strains of bacilli was studied. the plasmid transfer was possible not only between various strains of b. subtilis, but also when many other species of bacilli served as recipients. conjugation of a donor strain b. subtilis 19 (p19pub110) was accompanied by a transfer of plasmid p19 along with plasmid pub110 to the b. subtilis recipient strains lacking a large plasmid p19. if, like the donor cells, the recipient b. subtilis strain carried plas ... | 2003 | 14515473 |
| efficacy of bacillus thuringiensis israelensis, bacillus sphaericus and temephos for managing anopheles larvae in eritrea. | we evaluated the larvicidal activity of the granular formulation of bacillus thuringiensis israelensis (bti) serotype h-14 (vectobac g, 200 itu/mg) and bacillus sphaericus (bsph) serotype h5a5b (vectolex cg, 670 bs itu/mg) against anopheles arabiensis and other mosquitoes in breeding habitats in 3 sites, gash-barka, anseba, and debub zones, in eritrea. the primary objective was to determine the optimal application rate and duration of effect for bti and bsph in representative larval habitats as ... | 2003 | 14524547 |
| specific oxygen uptake rate variations during batch fermentation of bacillus thuringiensis subspecies kurstaki hd-1. | the specific oxygen uptake rate (q(o)2, respiration rate) of bacillus thuringiensis subsp. kurstaki hd-1 was very high at inoculation and was found to decrease essentially monotonically throughout both vegetative growth phase and transition phase under different batch culture conditions. average q(o)2 values decreased from 8-10 mmol/g h at 1 h after inoculation to less than 2 mmol/g h by the time growth ended. the results are shown to be consistent with the few previous reports on q(o)2 in b. th ... | 2003 | 14524704 |
| mutation of the hydrophobic residue on helix alpha5 of the bacillus thuringiensis cry4b affects structural stability. | cry4b toxin is a mosquito-larvicidal protein from the bacillus thuringiensis subsp. israelensis. we have investigated the role of two conserved hydrophobic residues of cry4b in structural stabilization. substitutions of the leucine-175 and isoleucine-189 on helix alpha5 with valine and leucine did not affect the expression level, solubility and proteolytic processing. steady state analysis of an unfolding experiment as monitored by circular dichroism and fluorescence spectroscopy demonstrated a ... | 2003 | 14529489 |
| a novel real-time quantitative pcr method using attached universal template probe. | a novel real-time quantitative polymerase chain reaction (pcr) method using an attached universal template (ut) probe is described. the ut is an approximately 20 base attachment to the 5' end of a pcr primer, and it can hybridize with a complementary taqman probe. one of the advantages of this method is that different target dna sequences can be detected employing the same ut probe, which substantially reduces the cost of real-time pcr set-up. in addition, this method could be used for simultane ... | 2003 | 14530456 |
| dual resistance to bacillus thuringiensis cry1ac and cry2aa toxins in heliothis virescens suggests multiple mechanisms of resistance. | one strategy for delaying evolution of resistance to bacillus thuringiensis crystal (cry) endotoxins is the production of multiple cry toxins in each transgenic plant (gene stacking). this strategy relies upon the assumption that simultaneous evolution of resistance to toxins that have different modes of action will be difficult for insect pests. in b. thuringiensis-transgenic (bt) cotton, production of both cry1ac and cry2ab has been proposed to delay resistance of heliothis virescens (tobacco ... | 2003 | 14532042 |
| use of denaturing high-performance liquid chromatography to identify bacillus anthracis by analysis of the 16s-23s rrna interspacer region and gyra gene. | denaturing high-performance liquid chromatography (dhplc) was evaluated as a method for identifying bacillus anthracis by analyzing two chromosomal targets, the 16s-23s intergenic spacer region (isr) and the gyra gene. the 16s-23s isr was analyzed by this method with 42 strains of b. anthracis, 36 strains of bacillus cereus, and 12 strains of bacillus thuringiensis; the gyra gene was analyzed by this method with 33 strains of b. anthracis, 27 strains of b. cereus, and 9 strains of b. thuringiens ... | 2003 | 14532217 |
| a new multiplex pcr for the detection of hbl genes in strains of the 'bacillus cereus group'. | 2003 | 14535496 | |
| identification of two isoforms of aminopeptidase n in aedes aegypti larval midgut. | the bacterium bacillus thuringiensis produces toxin inclusions that are deleterious to target insect larvae. these toxins are believed to interact with a specific receptor protein(s) that is present on the gut epithelial cells of the larvae. in various insect species (in particular those belonging to the lepidopteran class), aminopeptidase n (apn) is one of the two receptor proteins that are considered to be involved in toxin-receptor interactions. however, in mosquitoes, the nature and identity ... | 2003 | 14536036 |
| recent developments in the biotechnology of bacillus thuringiensis. | 2000 | 14538115 | |
| bacillus thuringiensis insecticidal crystal toxins: gene structure and mode of action. | thanks to the techniques of recombinant dna, there is now abundant sequence information on several endotoxin genes of bacillus thuringiensis. the task of correlating this sequence information with the economically important aspects of the toxins such as insect specificity, ld(50) and speed of kill is now under worldwide investigation. progress has also been made on understanding the mechanism of action of the toxins and on identifying the parts of the protoxin which are important in toxicity. ta ... | 1988 | 14550036 |
| detection of corn intrinsic and recombinant dna fragments and cry1ab protein in the gastrointestinal contents of pigs fed genetically modified corn bt11. | genetically modified corn has been approved as an animal feed in several countries, but information about the fate of genetically modified dna and protein in vivo is insufficient. genetically modified corn bt11 is developed by inserting a recombinant dna sequence encoding insecticidal cry1ab protein from bacillus thuringiensis subsp. kurstaki. we examined the presence of corn intrinsic and recombinant cry1ab gene by pcr, and the cry1ab protein by immunological tests in the gastrointestinal conte ... | 2003 | 14552382 |
| a bacillus thuringiensis delta-endotoxin induces programmed cell death in mosquito larvae. | we present evidence that a delta-endotoxin isolated from bacillus thuringiensis subsp.israelensis induces programmed cell death in polytene midgut cells of culex pipiens larvae. after exposure to toxin, polytene nuclei in the anterior region of the larval midgut undergo many of the morphological and physiological changes which are characteristic of apoptosis, including the ability to stain with the vital dye, acridine orange, and fragmentation of nuclear dna as demonstrated by agarose gel electr ... | 1997 | 14555969 |
| a delta-endotoxin encoded in pseudomonas fluorescens displays a high degree of insecticidal activity. | the short field-life of bacillus thuringiensis (bt) insecticidal crystal protein has limited its use. when the bt toxin is produced in pseudomonas fluorescens it can be encapsulated and retain its effectiveness for two to three times longer than other bt formulations. in order to improve bt expression, we have synthesized cryia(c) bt delta-endotoxin encoding region (genbank af537267) according to the usage codon of p. fluorescens and transformed the bt toxin expression cassette into p. fluoresce ... | 2003 | 14556036 |
| microbial ecology of bacillus thuringiensis: fecal populations recovered from wildlife in korea. | a total of 34 fecal samples, collected from 14 species of wild mammals in korea, were examined for the occurrence of bacillus thuringiensis. the organism was detected in 18 (53%) samples. among the three food-habit groups, herbivorous animals yielded the highest frequency (69%) of samples positive for b. thuringiensis, followed by omnivorous animals (50%). of the six fecal samples from carnivorous animals, only one sample contained b. thurin giensis. among 527 isolates belonging to the bacillus ... | 2003 | 14569287 |
| [inheritance and segregation of transformants in cotton with two types of insect-resistant genes]. | a plant expression vector containing a chemeric bt29k gene coding for the active cry1ac protein and the arrowhead proteinase inhibition gene api-b was introduced into an elite cotton cultivar jihe 321 by agrobactertium tumefaciens. some insect-resistant cotton lines were developed. segregation and stabilization of insect-resistant genes in six transformation lines were studied. based on the results of kanamycin resistant test and insect bioassay using heliethis armigera, pcr detection and southe ... | 2003 | 14579531 |
| rapid digestion of cry34ab1 and cry35ab1 in simulated gastric fluid. | two genes were identified in bacillus thuringiensis berliner (bt) that code for the proteins that comprise a cry34ab1/cry35ab1 binary insecticidal crystal protein. maize, zea mays l., plants have been transformed to express the cry34ab1/cry35ab1 proteins, and as a result, these plants are resistant to attack by western corn rootworm, diabrotica virgifera virgifera leconte, a major pest in the midwestern corn-growing area of the u.s.a. as part of the safety assessment for the proteins, digestibil ... | 2003 | 14582981 |
| mosquito larvicidal activity of transgenic anabaena pcc 7120 expressing toxin genes from bacillus thuringiensis subsp. israelensis. | genes encoding the mosquito larvicidal toxins cry4aa, cry11aa, cyt1aa and the regulatory p20 from bacillus thuringiensis subsp. israelensis were introduced into the nitrogen-fixing, filamentous cyanobacterium anabaena pcc 7120 for expression under control of two strong promoters p(psba) and p(a1). the clone prve4-adrc displayed toxicity against fourth-instar larvae of aedes aegypti, the highest ever achieved in cyanobacteria. it was about 2.5-fold more toxic than the respective clone without cyt ... | 2003 | 14592708 |
| artificial carrier for oxygen supply in biological systems. | several poly (dimethylsiloxanes) (pdms) copolymers of dimethylsiloxane (dms) with ethylene or propylene oxide were tested as artificial carriers for the delivery of oxygen to biological systems. copolymers with a dms content of 33% or lower enhanced glucose oxidation by 200% in contrast to the 25% increase produced by the same concentration of perfluorodecalin. when 0.05% of the copolymer with 18% dms was included in the growth media of bacillus thuriginensis, the biomass (growth rate) increased ... | 2004 | 14593505 |
| susceptibility profile of culex quinquefasciatus (diptera: culicidae) to bacillus sphaericus on selection with rotation and mixture of b. sphaericus and b. thuringiensis israelensis. | several strains of bacillus sphaericus (neide) (bsph), a spore-forming bacterium that produces potent mosquitocidal toxins, have been widely used against mosquito larvae globally. in some locations in the field and in the laboratory, moderate to high levels of resistance in culex pipiens complex mosquito larvae to bsph have been reported. practical strategies for dealing with the resistance problem and more importantly to delay or possibly prevent development of resistance to bsph in the first p ... | 2003 | 14596281 |
| protection of mice infected with plasmodium berghei by bacillus thuringiensis crystal proteins. | eight bacillus thuringiensis strains were used to test their activity against plasmodium berghei. when crystal proteins extracted from strains 007, 017, 020, 021, 030, 032, and 037 were injected into plasmodium-infected mice through the tail vein at a rate of 0.45-1.5 mg per mouse, the lengths of survival for the mice were extended up to 5 days (from 8.5 days to 13.5-15 days). blood-cell staining demonstrated that normal erythrocytes were lightly stained and regularly shaped while the erythrocyt ... | 2004 | 14600831 |
| transgenic plants expressing two bacillus thuringiensis toxins delay insect resistance evolution. | preventing insect pests from developing resistance to bacillus thuringiensis (bt) toxins produced by transgenic crops is a major challenge for agriculture. theoretical models suggest that plants containing two dissimilar bt toxin genes ('pyramided' plants) have the potential to delay resistance more effectively than single-toxin plants used sequentially or in mosaics. to test these predictions, we developed a unique model system consisting of bt transgenic broccoli plants and the diamondback mot ... | 2003 | 14608363 |
| rapid evolution and the cost of resistance to bacillus thuringiensis in greenhouse populations of cabbage loopers, trichoplusia ni. | the microbial insecticide bacillus thuringiensis (bt) has become the mainstay of non-chemical control of lepidopteran pests, either as sprays or through the incorporation of bt toxins into transgenic crops. given the wide use of bt, it is striking that currently only one pest species, plutella xylostella, has been reported to have developed significant resistance to bt outside the laboratory. by contrast, we report here the frequent and rapid development of resistance to b. thuringiensis kurstak ... | 2003 | 14613613 |
| the bacillus thuringiensis linear double-stranded dna phage bam35, which is highly similar to the bacillus cereus linear plasmid pbclin15, has a prophage state. | bam35, a 15-kbp double-stranded dna phage, infects bacillus thuringiensis. recently, sequencing of the related bacillus cereus revealed a 15.1-kbp linear plasmid, pbclin15. we show that pbclin15 closely resembles bam35 and demonstrate conversion of bam35 to a prophage. this state is common, as several b. thuringiensis strains release bam35-related viruses. | 2003 | 14617663 |
| inheritance of resistance to bt canola in a field-derived population of plutella xylostella. | crops expressing bacillus thuringiensis (bt) insecticidal cry proteins are grown on millions of hectares. recommendations to delay resistance are based on a high expression/refugia strategy that aims to kill resistant heterozygotes and enable some susceptible insects to survive. leaf-dip bioassays on f1 crosses of malaysian populations of diamondback moth (plutella xylostella (l)) showed that crylac resistance was not fully recessive. the survival of ca 50% of heterozygotes on bt canola (brassic ... | 2003 | 14620045 |
| decontamination of bacillus thuringiensis spores on selected surfaces by chlorine dioxide gas. | this work examined the efficacy of chlorine dioxide (clo2) gas for the decontamination of bacillus thuringiensis spores on paper, wood, epoxy, and plastic surfaces. spores representing an inoculation level of approximately 6 log colony-forming units (cfu) per surface were treated with 5, 10, 15, 20, 25, or 30 milligrams per liter (mg/l) clo2 gas for 12 hours under 85-92 percent relative humidity and at 22 +/- 1 degrees c. under the tested treatment conditions, the highest population of surviving ... | 2003 | 14621648 |
| sustainability of insect resistance management strategies for transgenic bt corn. | increasing interest in the responsible management of technology in the industrial and agricultural sectors of the economy has been met thorough the development of broadly applicable tools to assess the "sustainability" of new technologies. an arena ripe for application of such analysis is the deployment of transgenic crops. the new transgenic pesticidal or plant-incorporated protectant (pip) crops have seen widespread application in the united states based on the features of higher yield, lower ... | 2003 | 14623043 |
| cloning and expression of the insecticidal crystal protein gene cry1ca9 of bacillus thuringiensis g10-01a from taiwan granaries. | a new cry gene (cry1ca9) was cloned and sequenced from a bacillus thuringiensis isolate native to taiwan (g10-01a). the cry1c-type gene, designated cry1ca9, consisted of an open reading frame of 3,567 bp, encoding a protein of 1,189 amino acid residues. the polypeptide has the deduced amino acid sequences predicting molecular masses of 134.7 kda. the gene sequence was compared against the genbank nucleotide sequence data base. it was found that the cry1ca9 gene coded for a 134.7-kda protoxin whi ... | 2003 | 14629010 |
| a bacillus thuringiensis isolate possessing a spore-associated filament. | we report on a novel bacterium, isolated during a screen for environmental isolates of bacillus thuringiensis, that possesses a novel filamentous structure. nucleotide sequence from the isolate's 16s rrna gene places the bacterium unambiguously within the bacillus thuringiensis/bacillus cereus group. phase-contrast and electron microscopy indicate the presence of both a parasporal body and a long filament which are retained after sporulation. the filament is shown to consistently arise from the ... | 2003 | 14629020 |
| characterization of a mosquitocidal bacillus thuringiensis serovar sotto strain isolated from okinawa, japan. | to characterize the mosquitocidal activity of parasporal inclusions of the bacillus thuringiensis serovar sotto strain 96-ok-85-24, for comparison with two well-characterized mosquitocidal strains. | 2003 | 14633026 |
| detection and characterization of the novel bacteriocin entomocin 9, and safety evaluation of its producer, bacillus thuringiensis ssp. entomocidus hd9. | to identify and characterize new bacteriocins from a collection of 41 strains belonging to 27 subspecies of bacillus thuringiensis, and to evaluate the safety of the producers. | 2003 | 14633027 |
| bt: mode of action and use. | the insecticidal toxins from bacillus thuringiensis (bt) represent a class of biopesticides that are attractive alternatives to broad-spectrum "hard" chemistries. the u.s. food quality protection act and the european economic council directives aimed at reducing the use of carbamate and organophosphate insecticides were expected to increase the use of narrowly targeted, "soft" compounds like bt. here we summarize the unique mode of action of bt, which contributes to pest selectivity. we also rev ... | 2003 | 14635181 |
| modelling the spatial configuration of refuges for a sustainable control of pests: a case study of bt cotton. | the 'high-dose-refuge' (hdr) strategy is widely recommended by the biotechnology industry and regulatory authorities to delay pest adaptation to transgenic crops that produce bacillus thuringiensis (bt) toxins. this involves cultivating nontoxic plants (refuges) in close proximity to crops producing a high dose of bt toxin. the principal cost associated with this strategy is due to yield losses suffered by farmers growing unprotected, refuge plants. using a population genetic model of selection ... | 2003 | 14635838 |
| a plasmid encoding a combination of mosquito-larvicidal genes from bacillus thuringiensis subsp. israelensis and bacillus sphaericus confers toxicity against a broad range of mosquito larvae when expressed in gram-negative bacteria. | a recombinant plasmid harboring cry4a, cry4b and cry11a from bacillus thuringiensis subsp. israelensis and binary toxin genes from bacillus sphaericus has been constructed. the three cry genes were placed under the control of the cry4b promoter whereas the binary toxin gene was controlled by its native promoter. the expression of toxins in escherichia coli harboring the resulting plasmid, p4bda-5142, was investigated. cry4b expression was highest compared to other toxins. although the level of t ... | 2003 | 14638432 |
| functional domains of a pore-forming cardiotoxic protein, volvatoxin a2. | volvatoxin a2 (vva2), a novel pore-forming cardiotoxic protein was isolated from the mushroom volvariella volvacea. we identified an n-terminal fragment (ntf) (1-127 residues) of vva2 as a domain for oligomerization by limited tryptic digestion. on preincubation of ntf with vva2, ntf was found to inhibit vva2 hemolytic activity by inducing vva2 oligomerization in the solution in the same manner as liposomes. by site-directed mutagenesis, the amphipathic alpha-helix b of ntf or vva2 was shown to ... | 2004 | 14645370 |
| bt-resistance management--theory meets data. | 2003 | 14647327 | |
| spatial and temporal patterns of green fluorescent protein (gfp) fluorescence during leaf canopy development in transgenic oilseed rape, brassica napus l. | the green fluorescent protein (gfp) holds promise as a field-level transgene marker. one obstacle to the use of gfp is fluorescence variability observed within leaf canopies. in growth chamber and field experiments, gfp fluorescence in transgenic oilseed rape ( brassica napus) was shown to be variable at each leaf position over time and among different leaves on the same plant. a leaf had its highest gfp fluorescence after emergence and, subsequently, its fluorescence intensity decreased. gfp fl ... | 2003 | 14648109 |
| fed-batch culture of bacillus thuringiensis based on motile intensity. | the operation of a fed-batch culture is more complicated than that of batch or continuous culture. thus, an appropriate feeding strategy for fed-batch cultures should be carefully designed. in this study, a simple feeding strategy for fed-batch culture of bacillus thuringiensis based on "motile intensity" is described. the feeding strategy consisted of two steps: (1) initiating feeding at the peak of motile intensity; (2) terminating feeding at low motile intensity (or non-motility) of the cells ... | 2003 | 14648344 |
| overwintering of heliothis virescens (f.) and helicoverpa zea (boddie) (lepidoptera: noctuidae) in cotton fields of northeast mississippi. | following the 1995-2001 crop seasons, population densities of pupae of tobacco budworm, heliothis virescens (f.), and corn earworm, helicoverpa zea (boddie), overwintering in cotton fields, gossypium hirsutum l., in monroe county, ms, were estimated by digging a total of 43,542 m-row. densities of pupae varied greatly among years with the highest densities occurring in years with low rainfall in the late summer and early fall. the sex ratio of pupae was variable and significantly male-biased in ... | 2003 | 14650516 |
| stable bacillus thuringiensis (bt) toxin content in interspecific f1 and backcross populations of wild brassica rapa after bt gene transfer. | stable expression of a transgene may lead to increased fitness for wild plants after acquiring the transgene via crop-weed hybridization. here, we investigate the stability of bt toxin content in wild brassica rapa acquiring the bt gene from bt brassica napus. the bt toxin content in nine bt-expressing b. napus lines was 0.80-1.70 micro g/g leaf tissue throughout the growing season. these nine lines were crossed with three accessions of wild b. rapa and the bt gene was successfully transferred t ... | 2004 | 14653804 |
| binding and toxicity of bacillus thuringiensis protein cry1c to susceptible and resistant diamondback moth (lepidoptera: plutellidae). | we studied mechanisms of resistance to bacillus thuringiensis insecticidal crystal protein cry1c in the diamondback moth, plutella xylostella (l.). binding assays with midgut brush border membrane vesicles prepared from whole larvae showed no significant difference between resistant and susceptible strains in binding of radioactively-labeled cry1c. these results indicate that reduced binding of cry1c to midgut membrane target sites did not cause resistance to cry1c. thus, the mechanism of resist ... | 2000 | 14658503 |
| heritability of tolerance to the cry1ab toxin of bacillus thuringiensis in chilo suppressalis (lepidoptera: crambidae). | heritability of chilo suppressalis (walker) tolerance to the cry1ab toxin of bacillus thuringiensis berliner was estimated using a half-sibling design. artificial diet with and without cry1ab was infested with progenies of 20 males, each mated with 2 females, and mortality was scored 5 d after infestation. the progeny of each female was reared and scored separately. mean mortality of the 20 families on the cry1ab diet was 46.5%. the effects of both male parent and of female parent within male pa ... | 2000 | 14658505 |
| frequency of resistance to bacillus thuringiensis toxin cry1ab in an iowa population of european corn borer (lepidoptera: crambidae). | the refuge plus high-dose strategy for resistance management assumes that the frequency of resistance alleles is low. we used an f2 screen to estimate the frequency of resistance to transgenic corn that produces bacillus thuringiensis berliner cry1ab toxin (bt corn) in an iowa population of european corn borer, ostrinia nubilalis (hübner). we also proposed a modification to the statistical analysis of the f2 screen that extends its application for nonuniform prior distributions and for repeated ... | 2000 | 14658507 |
| biological control agents for white grubs (coleoptera: scarabaeidae) in anticipation of the establishment of the japanese beetle in california. | we tested biological control agents for the control of 3rd-instar scarab turfgrass pests, both for the masked chafer cyclocephala hirta leconte and the japanese beetle, popillia japonica newman. the former species is endemic in california whereas the latter, although not yet established, constitutes a permanent serious threat to agriculture and horticulture in california. we conducted experiments using c. hirta in california and p. japonica in new jersey. a field trial conducted in 2 different c ... | 2000 | 14658514 |
| colorado potato beetle (coleoptera: chrysomelidae) feeding, development, and survival to adulthood after continuous exposure to bacillus thuringiensis subsp. tenebrionis-treated potato foliage from the field. | colorado potato beetle, leptinotarsa decemlineata (say), feeding, development, and survival to adulthood were examined after continuously exposing large larvae to bacillus thuringiensis subsp. tenebrionis-treated potato foliage from the field. in laboratory assays, the overall consumption and the length of period to become prepupae were determined for larvae, which began as 3rd and 4th instars, that were offered potato leaf disks with naturally declining levels of b. thuringiensis residue. in sm ... | 2000 | 14658525 |
| identification of bacterial spores using statistical analysis of fourier transform infrared photoacoustic spectroscopy data. | fourier transform infrared photoacoustic spectroscopy (ftir-pas) has been applied for the first time to the identification and speciation of bacterial spores. a total of forty specimens representing five strains of bacillus spores (bacillus subtilis atcc 49760, bacillus atrophaeus atcc 49337, bacillus subtilis 6051, bacillus thuringiensis subsp. kurstaki, and bacillus globigii dugway) were analyzed. spores were deposited, with minimal preparation, into the photoacoustic sample cup and their spec ... | 2003 | 14661830 |
| compaction of the escherichia coli nucleoid caused by cyt1aa. | compaction of the escherichia coli nucleoid in the cell's centre was associated with the loss of colony-forming ability; these effects were caused by induction of cyt1aa, the cytotoxic 27 kda protein from bacillus thuringiensis subsp. israelensis. cyt1aa-affected compaction of the nucleoids was delayed but eventually more intense than compaction caused by chloramphenicol. the possibility that small, compact nucleoids in cyt1aa-expressing cells resulted in dna replication run-out and segregation ... | 2003 | 14663087 |
| effect of sm(3+) ion on growth of bacillus thuringiensis by microcalorimetry. | by using an lkb-2277 bioactivity monitor, cycle-flow method, the thermogenic curves of aerobic growth for bacillus thuringiensis cry ii strain at 28 degrees c have been obtained. the metabolic thermogenic curves of b. thuringiensis cry ii contained two distinct patterns: the first reflects the changes during the bacterial growth phase and the second corresponds to the sporulation phase. from these thermogenic curves in the absence and presence of sm(3+) ions, the thermokinetic parameters such as ... | 2003 | 14665732 |
| [potential of bacillus thuringiensis israelensis berliner for controlling aedes aegypti]. | the importance of the entomopathogenic bacterium bacillus thuringiensis israelensis in the control of aedes aegypti is presented. the use and potential of b. thuringiensis israelensis against the mosquito vector of dengue fever is described. other aspects such as insect's resistance development against chemicals and advantages and constraints of using microbial control are discussed. emphasis is given to the importance of the use of this bacterium in brazil, which could contribute significantly ... | 2003 | 14666315 |
| effect of food processing on the fate of dna with regard to degradation and transformation capability in bacillus subtilis. | soymilk, tofu, corn masa, and cooked potato were produced from transgenic raw materials and the effect of processing on the degradation of dna was studied. major degrading factors were for soymilk and tofu the mechanical treatment of soaked soybeans and for corn masa and cooked potatoes the thermal treatment. in the processed foods no dna fragments > 1.1 kb were detected. we included in our studies the effect of the size of donor dna and length of the homologous sequence on the marker rescue tra ... | 2003 | 14666975 |
| cry29a and cry30a: two novel delta-endotoxins isolated from bacillus thuringiensis serovar medellin. | two novel crystal protein genes from a highly mosquitocidal bacillus thuringiensis serovar medellin strain were cloned and sequenced. the corresponding proteins, cry29a and cry30a, were nontoxic when tested individually against the mosquito species bioassayed (aedes aegypti, culex pipiens and anopheles stephensi). however, cry29a synergized the toxicity of cry11bb against aedes aegypti by a four-fold factor. | 2003 | 14666976 |
| ion channels formed in planar lipid bilayers by the dipteran-specific cry4b bacillus thuringiensis toxin and its alpha1-alpha5 fragment. | trypsin activation of cry4b, a 130-kda bacillus thuringiensis (bt) protein, produces a 65-kda toxin active against mosquito larvae. the active toxin is made of two protease resistant-products of ca. 45 kda and ca. 20 kda. the cloned 21-kda fragment consisting of the n-terminal region of the toxin was previously shown to be capable of permeabilizing liposomes. the present study was designed to test the following hypotheses: (1) cry4b, like several other bt toxins, is a channel-forming toxin in pl ... | 2004 | 14668140 |
| sequencing and characterization of plasmid puibi-1 from bacillus thuringiensis serovar entomocidus lbit-113. | plasmid puibi-1 from bacillus thuringiensis svr. entomocidus was sequenced and its replication mechanism analyzed. sequence analysis revealed that puibi-1 contains 4671 bp and a 32% gc content. plasmid puibi-1 also includes at least seven putative open reading frames (orfs) encoding for proteins ranging from 5 to 50 kda. orf-1 encodes for a putative 16-kda rep protein, which lacks homology with proteins of similar function. orf2 encodes for a protein of 50 kda and shows homology with mob protein ... | 2003 | 14669916 |
| distribution analysis of is231-like sequences among bacillus thuringiensis serovars inferred from restriction fragment length polymorphisms. | the distribution of is231 has been analyzed in bacillus thuringiensis serovars. a 723-bp haeii conserved fragment from is231m has been used as a probe against ecori-digested b. thuringiensis total dna to yield serovar-specific hybridization profiles. the approach was useful at revealing the extent of distribution of is231-like sequences between and within strains. of the 88 b. thuringiensis strains tested, 70 showed hybridization banding patterns that comprised between one and 20 distinct bands. ... | 2003 | 14669921 |
| [on the adaptive nature of the dissociation process in bacillus thuringiensis]. | the process of dissociation into variants differing in colony morphology occurring in batch cloned cultures of two bacillus thuringiensis strains belonging to different subspecies was studied at optimal and elevated temperatures. an increase in the cultivation temperature to 40 degrees c resulted in an increase in the fraction of r variants to 100% after 72 h of cultivation of either of the strains. this increase was not due to the selection of forms with greater resistance to elevated temperatu ... | 2003 | 14679909 |
| the ispa protease's involvement in the regulation of the sporulation process of bacillus thuringiensis is revealed by proteomic analysis. | we have observed that the process of sporulation of the ispa-deficient mutant was delayed under phase-contrast microscopy. the protein profiles of the ispa-deficient mutant have been analyzed using two-dimensional gel electrophoresis. the results of a proteomic analysis using maldi-tof ms indicated that a sporulation-associated protein, pro- [formula: see text], was upregulated, while two other sporulation-associated proteins, spovd and spovr, were downregulated in the ispa-deficient mutant. it ... | 2003 | 14680823 |
| [construction of insecticidal recombinant bacillus thuringiensis using an integrative vector]. | insecticidal crystal protein gene cry1c which is highly toxic to spodoptera exigua was cloned into an integrative vector pbmb-f7e, which was derived from bacillus thuringiensis transposon tn4430. the recombinant integrative plasmid pbmb-flc harboring the cry1c gene was gained and transformed into a wild-type bt strain ybt803-1. a transformant bmb803-a was obtained, and grown at 46 degrees c for about 120 generations, from which three recombinants with cry1c gene integrating into the chromosome w ... | 2003 | 14682242 |
| leaf ontogeny influences leaf phenolics and the efficacy of genetically expressed bacillus thuringiensis cry1a(a) d-endotoxin in hybrid poplar against gypsy moth. | we tested the hypothesis that ontogenetic variation in leaf chemistry could affect the efficacy of genetically expressed bacillus thuringiensis cry1a(a) d-endotoxin, and thus provide spatial variation in (1) foliage protection and (2) selective pressures that could delay the resistance of folivores. our model consisted of clonal hybrid populus plants (nc5339). consumption of foliage and relative growth rates of gypsy moth, lymantria dispar (l.) increased, and phenolic glycoside concentrations de ... | 2003 | 14682535 |
| production of biopesticides using wastewater sludge as a raw material--effect of process parameters. | production of bacillus thuringiensis (bt) based biopesticide was studied using hydrolysed or raw wastewater sludge as a raw material. the sludge hydrolysis was carried out at different ph (2, 4 and 6). the sludge after hydrolysis was sterilised at 121 degrees c for 30 minutes. the effect of temperature, ph and agitation speed on growth and toxin production was also investigated. the ph in the shake flask was controlled by adding 0.1 m tris buffer. the progress of the biopesticide production proc ... | 2003 | 14682592 |
| tryptophan spectroscopy studies and black lipid bilayer analysis indicate that the oligomeric structure of cry1ab toxin from bacillus thuringiensis is the membrane-insertion intermediate. | during intoxication, the cry protoxins must change from insoluble crystals into membrane-inserted toxins, which form ionic pores. binding of cry1a toxins to the cadherin receptor promotes the formation of a 250 kda oligomer. in this work, we analyzed for the first time the structural changes presented by cry1ab toxin upon membrane insertion. trp fluorescence of pure monomeric and oligomeric structures in solution and in a membrane-bound state was analyzed. cry1ab has nine trp residues, seven of ... | 2004 | 14705942 |
| a facile analytical method for the identification of protease gene profiles from bacillus thuringiensis strains. | five pairs of degenerate universal primers have been designed to identify the general protease gene profiles from some distinct bacillus thuringiensis strains. based on the pcr amplification patterns and dna sequences of the cloned fragments, it was noted that the protease gene profiles of the three distinct strains of b. thuringiensis subsp. kurstaki hd73, tenebrionis and israelensis t14001 are varied. seven protease genes, neutral protease b (nprb), intracellular serine protease a (ispa), extr ... | 2004 | 14706757 |
| development and use of an elisa test to detect ige antibody to cry9c following possible exposure to bioengineered corn. | starlink(tm), a variety of corn genetically engineered to contain the insecticidal protein cry9c, had not been approved for human consumption because it possessed some characteristics associated with allergenic proteins. however, in the fall of 2000 cry9c dna was detected in several corn-containing products, suggesting that starlink corn had entered the human food supply. subsequently, consumers, following consumption of corn products, reported a number of adverse health events, possibly consist ... | 2003 | 14707463 |
| a semifield evaluation of vectobac dt (abg-6499), a new formulation of bacillus thuringiensis israelensis for control of aedes albopictus. | we evaluated the effectiveness and duration of effectiveness of a new formulation of bacillus thuringiensis var. israelensis (bti) for control of larval aedes albopictus. the product tested was vectobac dt (abg-6499), a bti tablet formulation containing 3.4% of active ingredient (3,400 itu/mg) supplied by scae valent biosciences italy s.r.l. the study was conducted at the botanical garden of the university of rome "la sapienza" between june and september 2002, the most favorable season for the d ... | 2003 | 14710747 |
| maldi analysis of bacilli in spore mixtures by applying a quadrupole ion trap time-of-flight tandem mass spectrometer. | a novel ion trap time-of-flight hybrid mass spectrometer (qit-tof ms) has been applied for peptide sequencing in proteolytic digests generated from spore mixtures of bacilli. the method of on-probe solubilization and in situ proteolytic digestion of small, acid-soluble spore proteins has been recently developed in our laboratory, and microorganism identification in less than 20 min was accomplished. in this study, tryptic peptides were generated in situ from complex spore mixtures of b. subtilis ... | 2003 | 14710845 |
| characterization of bacillus spore species and their mixtures using postsource decay with a curved-field reflectron. | a strategy is proposed for the rapid identification of bacillus spores, which relies on the selective release of a family of proteins, referred to as small, acid-soluble spore proteins (sasps). in this work, sasps were selectively solubilized from bacillus spores on the maldi sample plate by using 10% tfa. proteolytic digests of sasps generated in situ from spores of b. subtilis 168, b. globigii, b. thuringiensis subs. kurstaki hd-1, b. cereus t, and the nonpathogenic strain b. anthracis sterne ... | 2003 | 14710846 |
| genetics of zwittermicin a production by bacillus cereus. | zwittermicin a represents a new chemical class of antibiotic and has diverse biological activities, including suppression of oomycete diseases of plants and potentiation of the insecticidal activity of bacillus thuringiensis. to identify genes involved in zwittermicin a production, we generated 4,800 transposon mutants of b. cereus uw101c and screened them for zwittermicin a accumulation. nine mutants did not produce detectable zwittermicin a, and one mutant produced eightfold more than the pare ... | 2004 | 14711631 |
| the action of cu2+ on bacillus thuringiensis growth investigated by microcalorimetry. | by using an lkb-2277 bioactivity monitor, ampoule mode, the heat output of bacillus thuringiensis growth metabolism has been determined at 28 degrees c and effect of cu2+ on b. thuringiensis growth was studied. copper has been regarded as an essential trace element for life. its deficiency may be the cause of diseases. cu2+ of different concentration have different effects on b. thuringiensis growth metabolism, cu2+ of low concentration (0-30 micrograms/ml) can promote the growth of b. thuringie ... | 2003 | 14714479 |
| detection of the bacillus anthracis gyra gene by using a minor groove binder probe. | identification of chromosomal markers for rapid detection of bacillus anthracis is difficult because significant chromosomal homology exists among b. anthracis, bacillus cereus, and bacillus thuringiensis. we evaluated the bacterial gyra gene as a potential chromosomal marker for b. anthracis. a real-time pcr assay was developed for the detection of b. anthracis. after analysis of the unique nucleotide sequence of the b. anthracis gyra gene, a fluorescent 3' minor groove binding probe was tested ... | 2004 | 14715750 |
| comparison of broiler performance when fed diets containing grain from yieldgard rootworm (mon863), yieldgard plus (mon810 x mon863), nontransgenic control, or commercial reference corn hybrids. | two 42-d experiments compared the nutritional value of yieldgard rootworm corn (mon863; experiment 1) and yieldgard plus corn (mon810 x mon863; experiment 2) to their respective nontransgenic controls and 6 commercial reference corn hybrids when fed to growing broilers. for each experiment, a randomized complete block design was used with 8 dietary treatments in each of 5 replicated blocks of pens. in experiment 1, no differences among diets were observed (p > 0.05) for final live weights and fe ... | 2003 | 14717553 |
| reagentless detection and classification of individual bioaerosol particles in seconds. | the rapid chemical analysis of individual cells is an analytical capability that will profoundly impact many fields including bioaerosol detection for biodefense and cellular diagnostics for clinical medicine. this article describes a mass spectrometry-based analytical technique for the real-time and reagentless characterization of individual airborne cells without sample preparation. we characterize the mass spectral signature of individual bacillus spores and demonstrate the ability to disting ... | 2004 | 14719885 |
| identification of 1-lysophosphatidylethanolamine (c(16:1)) as an antimicrobial compound in the housefly, musca domestica. | we observed that a methanolic whole body extract of uninfected last instar larvae of the housefly, musca domestica, displayed antifungal and antibacterial activity. we have further purified this extract to a single active fraction using reversed phase high performance liquid chromatography. the pure fraction inhibited growth of the gram-positive bacteria bacillus thuringiensis and the yeast saccharomyces cerevisiae, but not the gram-negative bacteria escherichia coli. the active compound was det ... | 2004 | 14723896 |
| analysis of the properties of bacillus thuringiensis insecticidal toxins using a potential-sensitive fluorescent probe. | a potential-sensitive fluorescent probe, 3,3'-dipropylthiadicarbocyanine iodide, was used to analyze, at ph 7.5 and 10.5, the effects of bacillus thuringiensis toxins on the membrane potential generated by the efflux of k(+) ions from brush border membrane vesicles purified from the midgut of the tobacco hornworm, manduca sexta. fluorescence levels were strongly influenced by the ph and ionic strength of the media. therefore, characterization of the effects of the toxins was conducted at constan ... | 2003 | 14724756 |
| [displaying polyhistidine peptide on the cell surface of bacillus thuringiensis by s-layer protein]. | cell surface layer (s-layer) is the outmost structure of bacterium cell and covers the intact cell. s-layer protein of bacillus thuringiensis strain ctc (ctc protein) was used as carrier protein to display polyhistidine (polyhis) peptides on the cell surface. series fusion protein genes were constructed by inserting dna fragments encoding (6his)1, (6his)2, (6his)3, (6his)9 and (6his)15 polyhis peptides into ctc protein gene at the site of downstream of slh domain. with the help of recombinant pl ... | 2003 | 14724939 |
| bacterial challenge stimulates innate immune responses in extra-embryonic tissues of tobacco hornworm eggs. | innate immunity protects juvenile and adult vertebrates and invertebrates against potential pathogens; however, it is unknown when developing embryos become immune competent and just how they are guarded from infection. to address these questions, we studied the effect of immune challenge on early stage eggs of the tobacco hornworm, manduca sexta. we detected many immune-related proteins and mrnas in naive eggs. upon immune challenge, antimicrobial protein genes were up-regulated, and antibacter ... | 2004 | 14728663 |
| expression of modified cry1ac gene of bacillus thuringiensis in transgenic tobacco plants. | several mutations were introduced into the cry1ac toxin gene, resulting in four variants with altered sequences that were responsible for low expression of the toxin in transgenic plants. these variants were as follows: v1, with modified three a/t-rich regions, including the first signal of transcription termination; v2, with modified five putative polyadenylation signals (polyadenylation signals pas) and the second signal of transcription termination; v3, with four initial auuua motifs; v4, wit ... | 2004 | 14734820 |
| detection of transgenic and endogenous plant dna in rumen fluid, duodenal digesta, milk, blood, and feces of lactating dairy cows. | the objective was to determine the presence or absence of transgenic and endogenous plant dna in ruminal fluid, duodenal digesta, milk, blood, and feces, and if found, to determine fragment size. six multiparous lactating holstein cows fitted with ruminal and duodenal cannulas received a total mixed ration. there were two treatments (t). in t1, the concentrate contained genetically modified (gm) soybean meal (cp4epsps gene) and gm corn grain (cry1a[b] gene), whereas t2 contained the near isogeni ... | 2003 | 14740846 |
| comparative delta-endotoxins of bacillus thuringiensis against mosquito vectors (aedes aegypti and culex pipiens). | pure crystals of seven bacillus thuringiensis field isolates from the lower silesia region (poland) were tested against larvae of aedes aegypti l. and culex pipiens l. (culicidae, diptera). the crystals of opq3 phylloplane isolate (belonging to the first biochemical type of b. thuringiensis subsp. japonensis, yoso, jinghongiensis) killed from 68 +/- 7% to 84 +/- 7% of the fourth instar larvae of a. aegypti. the crystals of two other strains (kpf3 and kpc1) of this group caused mortality between ... | 2003 | 14743982 |
| colloidal chitin stained with remazol brilliant blue r, a useful substrate to select chitinolytic microorganisms and to evaluate chitinases. | a simple and sensitive method based on the use of colloidal chitin stained with remazol brilliant blue r (rbb) is proposed to evaluate chitinase activity. if this colloidal-stained substrate is included as a carbon source in a liquid medium, this technique allows the selection or the comparison of chitinolytic microorganisms. the colloidal substrate is proportionally solubilized and the dye released is spectrophotometrically quantified at 595 nm. the procedures used for the staining and fixing o ... | 2004 | 14744450 |
| occurrence and linkage between secreted insecticidal toxins in natural isolates of bacillus thuringiensis. | little is known about the occurrence and linkage between secreted insecticidal virulence factors in natural populations of bacillus thuringiensis (bt). we carried out a survey of 392 bt strains isolated from various samples originating from 31 countries. the toxicity profile of the culture supernatants of these strains was determined individually against anthonomus grandis (coleoptera) and spodoptera littoralis (lepidoptera). we analyzed beta-exotoxin i production and searched for the genes enco ... | 2003 | 14756535 |
| selective antagonism to the cadherin bt-r1 interferes with calcium-induced adhesion of epithelial membrane vesicles. | bt-r(1) is a member of the cadherin superfamily of proteins and is expressed in the midgut epithelium of manduca sexta during larval development. previously, we showed that calcium ions influence the structure and stability of bt-r(1) on brush border membrane vesicles (bbmvs) prepared from m. sexta midgut epithelium. in the present study, the effects of calcium and cry1ab toxin, produced by bacillus thuringiensis, on the adhesive properties of bbmvs were investigated. addition of calcium to a su ... | 2004 | 14756577 |
| role of toxin activation on binding and pore formation activity of the bacillus thuringiensis cry3 toxins in membranes of leptinotarsa decemlineata (say). | binding and pore formation constitute key steps in the mode of action of bacillus thuringiensis delta-endotoxins. in this work, we present a comparative analysis of toxin-binding capacities of proteolytically processed cry3a, cry3b and cry3c toxins to brush border membranes (bbmv) of the colorado potato beetle leptinotarsa decemlineata (cpb), a major potato coleopteran-insect pest. competition experiments showed that the three cry3 proteolytically activated toxins share a common binding site. al ... | 2004 | 14757225 |
| [mosquito control based on larvicides in the state of rio grande do sul, brazil: choice of the control agent]. | a comparison between chemical and biological larvicides in routine operations against mosquitoes in rio grande do sul state was carried out in this study. in laboratory bioassays against culex quinquefasciatus, biological formulations vectobac 12 as and teknar 3000 (bacillus thuringiensis israelensis) as well as abg 6262 (b. sphaericus 2362), both in liquid and powder form, were highly effective. locally produced b. thuringiensis israelensis, formulations also yielded good results. among chemica ... | 2004 | 14762563 |
| insecticidal bacillus thuringiensis silences erwinia carotovora virulence by a new form of microbial antagonism, signal interference. | it is commonly known that bacteria may produce antibiotics to interfere with the normal biological functions of their competitors in order to gain competitive advantages. here we report that bacillus thuringiensis suppressed the quorum-sensing-dependent virulence of plant pathogen erwinia carotovora through a new form of microbial antagonism, signal interference. e. carotovora produces and responds to acyl-homoserine lactone (ahl) quorum-sensing signals to regulate antibiotic production and expr ... | 2004 | 14766576 |