Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
|---|
| genetic and biochemical approach for characterization of resistance to bacillus thuringiensis toxin cry1ac in a field population of the diamondback moth, plutella xylostella. | four subpopulations of a plutella xylostella (l.) strain from malaysia (f(4) to f(8)) were selected with bacillus thuringiensis subsp. kurstaki hd-1, bacillus thuringiensis subsp. aizawai, cry1ab, and cry1ac, respectively, while a fifth subpopulation was left as unselected (unsel-mel). bioassays at f(9) found that selection with cry1ac, cry1ab, b. thuringiensis subsp. kurstaki, and b. thuringiensis subsp. aizawai gave resistance ratios of >95, 10, 7, and 3, respectively, compared with unsel-mel ... | 2000 | 10742234 |
| development of a fluorogenic probe-based pcr assay for detection of bacillus cereus in nonfat dry milk. | a fluorogenic probe-based pcr assay was developed and evaluated for its utility in detecting bacillus cereus in nonfat dry milk. regions of the hemolysin and cereolysin ab genes from an initial group of two b. cereus isolates and two bacillus thuringiensis isolates were cloned and sequenced. three single-base differences in two b. cereus strains were identified in the cereolysin ab gene at nucleotides 866, 875, and 1287, while there were no species-consistent differences found in the hemolysin g ... | 2000 | 10742226 |
| probable identification of a membrane-associated repressor of bacillus subtilis dna replication as the e2 subunit of the pyruvate dehydrogenase complex. | two bacillus subtilis lysogenic libraries were probed by an antibody specific for a previously described membrane-associated inhibitor of b. subtilis dna replication (j. laffan and w. firshein, proc. natl. acad. sci. usa 85:7452-7456, 1988). three clones that reacted strongly with the antibody contained an entire open reading frame. sequencing identified one of the clones (r1-2) as containing the e2 subunit of the pyruvate dehydrogenase complex, dihydrolipoamide acetyltransferase. an at-rich seq ... | 2000 | 10735853 |
| cdnas of aminopeptidase-like protein genes from plodia interpunctella strains with different susceptibilities to bacillus thuringiensis toxins. | aminopeptidase n has been reported to be a bacillus thuringiensis (bt) cry1a toxin-binding protein in several lepidopteran insects. cdnas of aminopeptidase-like proteins from both bt-susceptible rc688s and bt-resistant hd198r strains of the indianmeal moth, plodia interpunctella, were cloned and sequenced. they contain 3345 and 3358 nucleotides, respectively, and each has a 3048 bp open reading frame that encodes 1016 amino acids. putative protein sequences include 10 potential glycosylation sit ... | 2000 | 10732989 |
| [effect of delta-endotoxin from bacillus thuringiensis var.tenebrionis on phospholipid vesicules]. | 2000 | 10732350 | |
| [conformation of delta-endotoxin from bacillus thuringiensis var.tenebrionis induced by methanol]. | 2000 | 10732349 | |
| bacillus thuringiensis crystal delta-endotoxin: role of proteases in the conversion of protoxin to toxin. | the conversion of delta-endoprotoxins of bacillus thuringiensis to active toxins is mediated by trypsin, insect gut (exogenous) and bacterial (endogenous) proteases. the biochemical aspects of exogenous and endogenous proteases involved in the conversion of protoxin to toxin are reviewed. perhaps, these proteases also play a role in influencing the host range of toxin and in the development of resistance to toxin. | 2000 | 10727765 |
| ecology. new corn plant draws fire from gm food opponents. | 2000 | 10722381 | |
| survival and conjugation of bacillus thuringiensis in a soil microcosm. | the survival and conjugation ability of sporogenic and asporogenic bacillus thuringiensis strains were investigated in broth, in non-amended sterile clay soil monoculture and in mixed soil culture. the 75 kb pht73 plasmid carrying an erythromycin resistance determinant and a cry1ac gene was transferred in mating broth and soil microcosm. survival of strains was assessed in soil monoculture and in mixed soil culture for up to 20 days. sporogenic strains rapidly formed viable spores which were mai ... | 2000 | 10719207 |
| [physicochemical and antimicrobial properties of chlorine-containing compositions ciaref and dp-1]. | the paper presents the results of the physicochemical properties and corrosive activity of the new chlorine-containing compositions ciaref and dp-1. various microbiological, biochemical, and biophysical studies were conducted to examine different aspects of the mechanism of action of ciaref and dp-1 on vegetative (francisella tularensis) and sporal (bacillus turingiensis) microorganisms. suspension, test-surface irrigation, and aerosol techniques were employed under close industrial conditions t ... | 1999 | 10709466 |
| efficacy of aqueous suspension and granular formulations of bacillus thuringiensis (vectobac) against mosquito vectors. | the efficacy of aqueous suspension (as) and granular (g) formulation of bacillus thuringiensis var. israelensis (vectobac) was tested against the immatures of mosquito vectors in the laboratory and under field conditions. laboratory tests showed that the aqueous suspension was relatively more effective against culex quinquefasciatus than aedes aegypti and anopheles stephensi, the respective lc(50) values being 0.046, 0.060 and 0.190 mg/l. in stream pools, with the application of vectobac as at 1 ... | 2000 | 10708664 |
| coexpression of cyt1aa of bacillus thuringiensis subsp. israelensis with bacillus sphaericus binary toxin gene in acrystalliferous strain of b. thuringiensis. | the cyt1aa gene of bacillus thuringiensis subsp. israelensis and binary toxin gene of bacillus sphaericus c3-41 were introduced into an acrystalliferous strain of b. thuringiensis independently and in combination by using shuttle vector pbu4. sds-page and western blot analysis proved that cyt1aa and binary toxin genes coexpressed during the sporulation of the recombinant. transformant strain expressing the cyt1aa and binary toxin proteins in combination was more toxic to susceptible and resistan ... | 2000 | 10706663 |
| germany holds up cultivation of gm maize... | 2000 | 10706253 | |
| field tests on managing resistance to bt-engineered plants. | several important crops have been engineered to express toxins of bacillus thuringiensis (bt) for insect control. in 1999, us farmers planted nearly 8 million hectares (nearly 20 million acres) of transgenic bt crops approved by the epa. bt-transgenic plants can greatly reduce the use of broader spectrum insecticides, but insect resistance may hinder this technology. present resistance management strategies rely on a "refuge" composed of non-bt plants to conserve susceptible alleles. we have use ... | 2000 | 10700153 |
| testing bt refuge strategies in the field. | 2000 | 10700135 | |
| characterization study of the sporulation kinetics of bacillus thuringiensis. | a wild-type and an rdna strain of bacillus thuringiensis were cultured in a net-draft-tube modified 20-l airlift bioreactor. a comparison of the sporulation patterns suggests that the early sporulation strain has a lower final spore count. results from off-gas analysis suggests that the co(2) profile could be an alternative indication to spore counts for the examination of fermentation performance or even the mortality in bioassay of the cultivation product. the difference in mortality tests exh ... | 2000 | 10699867 |
| cyt1a from bacillus thuringiensis synergizes activity of bacillus sphaericus against aedes aegypti (diptera: culicidae). | bacillus sphaericus is a mosquitocidal bacterium recently developed as a commercial larvicide that is used worldwide to control pestiferous and vector mosquitoes. whereas b. sphaericus is highly active against larvae of culex and anopheles mosquitoes, it is virtually nontoxic to aedes aegypti, an important vector species. in the present study, we evaluated the capacity of the cytolytic protein cyt1a from bacillus thuringiensis subsp. israelensis to enhance the toxicity of b. sphaericus toward a. ... | 2000 | 10698776 |
| cloning of two new cry genes from bacillus thuringiensis subsp. wuhanensis strain. | with pcr products as probes, we have cloned two new cry-type genes from bacillus thuringiensis subsp. wuhanensis. the deduced amino acid sequence of the first clone is 77.3% identical to cry1ga1. the deduced protein sequence of the second clone is 69.8-78.7% identical to that of cry1b group. the nomenclature assignment of these two clones is, therefore, named cry1gb1 and cry1bd1, respectively. the cry1bd1 is toxic to plutella xylostella larvae, and the cry1gb1 is toxic to pieris rapae larvae. | 2000 | 10688690 |
| occurrence of bacillus thuringiensis in fresh waters of japan. | bacillus thuringiensis was recovered at a relatively high frequency from both running and still fresh waters in natural environments of kyushu, japan. of 107 water samples examined, 53 (49.5%) contained this organism. the frequency of b. thuringiensis colonies was 4.4% among 4414 colonies of the bacillus cereus/b. thuringiensis group. the density of this bacterium in fresh waters averaged 0.45 cfu/ml. serologically, b. thuringiensis isolates were assigned to 26 h serotypes. of these, h14/36 (h s ... | 2000 | 10688688 |
| gene flow in the european corn borer ostrinia nubilalis: implications for the sustainability of transgenic insecticidal maize. | strategies proposed for delaying resistance to bacillus thuringiensis toxins expressed by transgenic maize require intense gene flow between individuals that grew on transgenic and on normal (referred to as refuges) plants. to investigate gene flow in the european corn borer, ostrinia nubilalis (hübner), the genetic variability at 29 sampled sites from france was studied by comparing allozyme frequencies at six polymorphic loci. almost no deviations from hardy-weinberg expectations occurred, and ... | 2000 | 10687815 |
| occurrence of bacillus thuringiensis on cured tobacco leaves. | a worldwide survey was conducted to evaluate the frequency and distribution of bacillus thuringiensis populations on cured tobacco leaves during post-harvest storage. in total, 133 tobacco samples of different types and origins were analyzed. nine percent of the samples showed the presence of b. thuringiensis, and 24 b. thuringiensis strains were isolated and characterized. the majority of the isolates produced bipyramidal crystals, and three fourths of them showed a second type of crystal prote ... | 2000 | 10679055 |
| the crystal proteins from bacillus thuringiensis subsp. thompsoni display a synergistic activity against the codling moth, cydia pomonella. | crystal proteins from bacillus thuringiensis subsp. thompsoni strain hnc are active against the codling moth, cydia pomonella, a major pest of orchards. inclusion bodies purified from strain hnc displayed an lc(50) of 3.34 x 10(-3) microgram/microliter. hnc-purified crystals were tenfold more active than cry2aa and cry1aa toxins, and 100-fold more toxic than cry1ab. the 34-kda and 40-kda proteins contained in hnc inclusion bodies were shown to act synergistically. the toxicity of crystal protein ... | 2000 | 10679054 |
| effects of media composition of delta-endotoxin production and morphology of bacillus thuringiensis in wild types and spontaneously mutated strains. | bacillus thuringiensis strains hd-73 and 4412, and two spontaneous mutants termed 4412aa-ind and 4412sph-cry were studied for the ability to produce crystals of different size and shape when grown in a rich medium and in an appropriate minimal medium defined during this study. strain 4412aa-ind showed medium-dependent variation in the crystal phenotype. scanning electron microscopy was utilized in order to show crystal variations in size and shape. b. thuringiensis strains 4412aa-ind and 4412sph ... | 2000 | 10677843 |
| chemical fingerprinting for the evaluation of unintended secondary metabolic changes in transgenic food crops. | a common element in designed guidelines for assessment of the food safety of transgenic crops is centred on a comparative analytical analysis with conventionally bred crop plants, assuming that these products have a long history of safe use (i.e. oecd-principle of substantial equivalence). in this study we examine the utility of an off-line combination of 400 mhz proton (1h)-nmr spectroscopy and liquid chromatography (lc) for the multi-component comparison of low-molecular weight compounds (i.e. ... | 2000 | 10674217 |
| compatibility of bacillus thuringiensis serovar israelensis and chemical insecticides for the control of aedes mosquitoes. | the compatibility of the commercial aqueous bacillus thuringiensis serovar israelensis (b.t.i.) formulation, vectobac 12as, with the chemical insecticides actellic 50ec, aqua resigen, resigen, and fendona sc, for the simultaneous control of aedes larvae and adults was studied by dispersing nine different formulations using a portable mist blower, in single story half-brick houses. the effectiveness of the treatment was evaluated by measuring the larval mortality, adult mortality, and droplet ana ... | 1999 | 10672551 |
| bacteria and mosquito abundance in microcosms enriched with organic matter and treated with a bacillus thuringiensis subsp. israelensis formulation. | bacteria and mosquito abundance were studied in outdoor tubs unenriched and enriched with 0.04% rabbit pellets during the winter, 1999. the irrigation water used to fill the tubs contained a total bacterial count of 1.15-1.35 x 10(3) cells/ml. adding rabbit pellets for enrichment yielded a total bacterial count of 5.50-7.63 x 10(5) cells/g. bacterial densities in unenriched water were significantly lower than in enriched tubs on every sampling day. when bacterial densities in both enriched and u ... | 1999 | 10672549 |
| mosquito control and bacterial flora in water enriched with organic matter and treated with bacillus thuringiensis subsp. israelensis and bacillus sphaericus formulations. | three tests were conducted during july 17 to october 30, 1998 to study the impact of two mosquitocidal microbial agents on mosquito larvae and their contribution to bacterial flora in aquatic microcosms. formulations of bacillus thuringiensis subsp. israelensis (bti) and bacillus sphaericus strain 2362 (bsph) were applied at various rates to outdoor tubs enriched with rabbit pellets and filled with irrigation water from a reservoir. mosquito larvae were effectively controlled by all treatments; ... | 1999 | 10672543 |
| detection of single-stranded cohesive ends in the genome of bacillus thuringiensis temperate phage kk-88. | cohesive ends (cos sites) were detected in the genome of temperate kk-88 phage in bacillus thuringiensis after analysis of the phage dna generated by the 3'-5' exonuclease activity of klenow fragment of dna polymerase i. in addition, unlike the 5'-protruding ends of coliphage lambda genome, the ends of kk-88 phage genome were found to be 3'-protruding. the restriction map of the phage genome was also constructed on the basis of position of the cos fragments. | 1999 | 10672343 |
| cdna sequence, mrna expression and genomic dna of trypsinogen from the indianmeal moth, plodia interpunctella. | trypsin-like enzymes are major insect gut enzymes that digest dietary proteins and proteolytically activate insecticidal proteins produced by the bacterium bacillus thuringiensis (bt). resistance to bt in a strain of the indianmeal moth, plodia interpunctella, was linked to the absence of a major trypsin-like proteinase (oppert et al., 1997). in this study, trypsin-like proteinases, cdna sequences, mrna expression levels and genomic dnas from bt-susceptible and -resistant strains of the indianme ... | 2000 | 10672067 |
| phase-specific optimization of multiple endotoxin-protein production with genetically engineered bacillus thuringiensis. | an optimization approach was designed to specifically study the toxin-expression phase of the fermentation process of a genetically engineered bacillus thuringiensis strain expressing dual toxin proteins (cryi and cryiii). the study has resulted in the discovery of important nutrient and process factors affecting toxin-protein yield. the results show that the existence of nitrogen sources in the medium during the toxin-expression phase is detrimental to the toxin-protein expression, while a high ... | 2000 | 10669405 |
| insecticidal activity of transgenic tobacco plants expressing both bt and cpti genes on cotton bollworm (helicoverpa armigera). | transgenic tobacco plants expressing both bacillus thuringiensis (bt) insecticidal protein and cowpea trypsin inhibitor (cpti) genes was used to evaluate the insecticidal activity on the cotton bollworm (helicoverpa armigera) compared with transgenic tobacco with bt insecticidal protein gene alone. mortality of first to third instar larvae fed on transgenic two genes tobacco for three days was significantly higher than that fed on transgenic bt tobacco. first to fourth instar larvae fed on trans ... | 1999 | 10668128 |
| larvicidal activity of bacillus thuringiensis isolated from jordanian habitats against drosophila melanogaster larvae. | bacillus thuringiensis was isolated from 23 of 37 samples obtained from different jordanian habitats. of the 37 samples, 187 different spore-forming colonies were selected and thirty (16%) were identified as b. thuringiensis based on their pathogenicity and production of parasporal inclusions. the lethal dose (ld50) of b. thuringiensis indicated a variation in their pathogenicity to drosophila melanogaster larvae. sensitivity of the first, the second and the third instar larvae of d. melanogaste ... | 1998 | 10664675 |
| characterization of the mucosal and systemic immune response induced by cry1ac protein from bacillus thuringiensis hd 73 in mice. | the present paper describes important features of the immune response induced by the cry1ac protein from bacillus thuringiensis in mice. the kinetics of induction of serum and mucosal antibodies showed an immediate production of anti-cry1ac igm and igg antibodies in serum after the first immunization with the protoxin by either the intraperitoneal or intragastric route. the antibody fraction in serum and intestinal fluids consisted mainly of igg1. in addition, plasma cells producing anti-cry1ac ... | 2000 | 10657055 |
| identification and purification of the 69-kda intracellular protease involved in the proteolytic processing of the crystal delta-endotoxin of bacillus thuringiensis subsp. tenebrionis. | the dynamics of appearance of intracellular proteases in relation to the synthesis of crystal delta-endotoxin was studied to identify the native intracellular protease(s) involved in the proteolytic processing of the 73-kda protoxin of bacillus thuringiensis subsp. tenebrionis. in vitro proteolytic activation of the 73-kda protoxin indicated the possible role of 69-kda protease in the proteolytic processing of 73-kda protoxin. the purified 69-kda protease was able to cause the proteolytic activa ... | 2000 | 10650203 |
| resistance to bt toxins. | 2000 | 10644220 | |
| bt toxin: assessing gm strategies. | 2000 | 10644219 | |
| regulation by overlapping promoters of the rate of synthesis and deposition into crystalline inclusions of bacillus thuringiensis delta-endotoxins. | during sporulation, bacillus thuringiensis produces intracellular, crystalline inclusions comprised of a mixture of protoxins active on insect larvae. a major class of these protoxin genes, designated cry1, is transcribed from two overlapping promoters (bti and btii) utilizing rna polymerase containing sporulation sigma factors sigma(e) and sigma(k), respectively. fusions of these promoters to lacz were constructed in order to analyze transcription patterns. mutations within the -10 region of th ... | 2000 | 10633108 |
| organizational complexity of a rice transgene locus susceptible to methylation-based silencing. | molecular analyses of a rice (oryza sativa l.) transgene locus introduced using biolistic techniques revealed the presence of multiple copies of rearranged fragments, as well as an intact copy of the supplied constructs. both the gene of interest (35s-btt cryiiia) and the selectable marker used (ubi1-bar) were methylated and silenced. additionally, vector sequences were present in great abundance and were also highly methylated, indicating that the entire transgene insert was marked for methylat ... | 1999 | 10632579 |
| natural coprevalence of strongwellsea castrans, cystosporogenes deliaradicae, and bacillus thuringiensis in the host, delia radicum. | adult cabbage root flies (delia radicum) from three danish localities were diagnosed microscopically for the natural prevalence of strongwellsea castrans, cystosporogenes deliaradicae, and bacillus thuringiensis. c. deliaradicae was significantly coprevalent with s. castrans. b. thuringiensis sporangia were diagnosed in the hemolymph in two d. radicum which were also infected with s. castrans and proved to belong to serovar aizawai and serovar balearica. the biological characterization of s. cas ... | 2000 | 10631060 |
| binding of bacillus thuringiensis cry1ac toxin to manduca sexta aminopeptidase-n receptor is not directly related to toxicity. | bacillus thuringiensis cry1ac delta-endotoxin specifically binds a 115-kda aminopeptidase-n purified from manduca sexta midgut. cry1ac domain iii mutations were constructed around a putative sugar-binding pocket and binding to purified aminopeptidase-n and brush border membrane vesicles (bbmv) was compared to toxicity. q509a, r511a, y513a, and 509-511 (qnr-aaa) eliminated aminopeptidase-n binding and reduced binding to bbmv. however, toxicity decreased no more than two-fold, indicating activity ... | 1999 | 10622728 |
| introduction of a mini-gene encoding a five-amino acid peptide confers erythromycin resistance on bacillus subtilis and provides temporary erythromycin protection in proteus mirabilis. | a 15-bp mini-gene was introduced into bacillus subtilis and into stable protoplast-like l-forms of proteus mirabilis. this mini-gene encoded the peptide mvlfv and modeled a fragment of escherichia coli 23s rrna responsible for e. coli erythromycin (ery) resistance. expression of the introduced mini-gene conferred permanent ery resistance on b. subtilis. in l-forms of p. mirabilis, the ery-protective effect was maintained in the course of several generations. herewith, the mechanism of ery resist ... | 2000 | 10620668 |
| plasmid transfer between the bacillus thuringiensis subspecies kurstaki and tenebrionis in laboratory culture and soil and in lepidopteran and coleopteran larvae. | plasmid transfer between bacillus thuringiensis subsp. kurstaki hd1 and b. thuringiensis subsp. tenebrionis donor strains and a streptomycin-resistant b. thuringiensis subsp. kurstaki recipient was studied under environmentally relevant laboratory conditions in vitro, in soil, and in insects. plasmid transfer was detected in vitro at temperatures of 5 to 37 degrees c, at ph 5.9 to 9.0, and at water activities of 0.965 to 0.995, and the highest transfer ratios (up to 10(-1) transconjugant/donor) ... | 2000 | 10618212 |
| field efficacy and nontarget effects of the mosquito larvicides temephos, methoprene, and bacillus thuringiensis var. israelensis in florida mangrove swamps. | we compared the efficacy and nontarget effects of temephos, bacillus thuringiensis var. israelensis (b.t.i.), and methoprene applied by helicopter to control mosquito larvae in mangrove swamps on sanibel island, fl, in may 1997. three sites per treatment and 3 untreated sites were used. temephos (abate) was applied at 37 ml/ha (43% active ingredient [ai]), b.t.i. granules (vectobac g) were applied at 5.606 kg/ha (200 international toxic units/mg), and methoprene (altosid all) was applied at 213 ... | 1999 | 10612606 |
| gm crops in the cross hairs. | 1999 | 10610557 | |
| bacillus thuringiensis cry1aa toxin-binding region of bombyx mori aminopeptidase n. | the bacillus thuringiensis cry1aa toxin-binding region of bombyx mori aminopeptidase n (apn) was analyzed, to better understand the molecular mechanism of susceptibility to the toxin and the development of resistance in insects. apn was digested with lysylendopeptidase and the ability of the resulting fragments to bind to cry1aa and 1ac toxins was examined. the binding abilities of the two toxins to these fragments were different. the cry1aa toxin bound to the fragment containing 40-asp to 313-l ... | 1999 | 10606725 |
| bacillus thuringiensis var. israelensis as a microbial control agent against adult and immature stages of the sandfly, phlebotomus papatasi under laboratory conditions. | the laboratory treatment of adult and immature stages of phlebotomus papatasi by the bacterial insecticide, bacillus thurnigiensis var. israelensis was carried out. different concentrations of b.t.i. mixed with fructose and glucose were assayed against the adult sandfly, while the immature stages were treated by offering larval diet contaminated by b.t.i. in different concentrations diluted by distilled water. b.t.i. could induce mortality to half of the larval and pupal population at 0.26 x 10( ... | 1999 | 10605508 |
| identification and characterization of the new bacillus thuringiensis serovars pirenaica (serotype h57) and iberica (serotype h59) | two new bacillus thuringiensis strains have been classified by the h antigen of the cells and differentiated by their morphological, biochemical and molecular characteristics. the flagellar agglutination showed that both strains bore specific h antigens which allowed their classification as the new serotypes h57 and h59. the serovar names proposed for the type strains characterized in this work are b. thuringiensis ser. pirenaica, for the h serotype 57, and b. thuringiensis ser. iberica, for the ... | 1999 | 10594703 |
| spherical parasporal inclusions of the lepidoptera-specific and coleoptera-specific bacillus thuringiensis strains: a comparative electron microscopic study. | four lepidoptera-specific bacillus thuringiensis strains that belong to the four h serogroups (serovars sumiyoshiensis, fukuokaensis, darmstadiensis, and japonensis) and a coleoptera (scarabaeidae)-specific strain belonging to serovar japonensis were examined for comparative ultrastructure of spherical parasporal inclusions. the prominent feature of the inclusions of the lepidoptera-specific strains was the existence of thick, highly electron-dense envelopes surrounding a homogeneous protein mat ... | 2000 | 10594228 |
| a replication origin of bacillus thuringiensis. | a replication origin of bacillus thuringiensis (bt) was found in a bacillus thuringiensis-escherichia coli shuttle vector of pht3101. deletion analysis showed that the replication origin was segregationally stable at suitable temperature for bt growth. the fragment containing the replication origin was cloned in puc18 and sequenced. it was 261 base pairs in length, located in the open reading frame 2 (orf2) of btspb sequence. the 261-bp fragment was cloned in pbr322, creating an improved bt-e. c ... | 2000 | 10594227 |
| pathogenicity of bacillus thuringiensis variety kurstaki to ixodes scapularis (acari: ixodidae). | pathogenicity of the entomopathogenic bacterium bacillus thuringiensis variety kurstaki de barjac & lemille was tested against the black-legged tick, ixodes scapularis say. engorged larvae dipped in a solution of 10(8) spores per milliliter showed 96% mortality 3 wk after infection. the lc50 value for engorged larve (concentration required to kill 50% of ticks) was 10(7) spores per milliliter. b. thuringiensis shows considerable potential as a microbial control agent for the management of i. sca ... | 1999 | 10593100 |
| insecticidal toxin in root exudates from bt corn. | 1999 | 10591205 | |
| sequence analysis of three bacillus cereus loci carrying picr-regulated genes encoding degradative enzymes and enterotoxin. | picr is a pleiotropic regulator of extracellular virulence factors in the opportunistic human pathogen bacillus cereus and the entomopathogenic bacillus thuringiensis, and is induced in cells entering stationary phase. among the genes regulated by picr are: pica, encoding phosphatidylinositol-specific phospholipase c (pi-plc); plc, encoding phosphatidylcholine-preferring phospholipase c (pc-plc); nhe, encoding the non-haemolytic enterotoxin; hbl, encoding haemolytic enterotoxin bl (hbl); and gen ... | 1999 | 10589720 |
| [insect-resistant transgenic plants of brassica napus and analysis of resistance in the plants]. | cotyledons, each with a 1-2 mm petiole at its base, were cut from axenic seedlings and infected with agrobacterium tumefaciens. after 2-3 days of cocultivation, the cotyledon explants were transferred to ms selection medium containing 15 mg/l kanamycin and 4.5 mg/l 6-ba to induce shoot differentiation. kanamycin-resistant shoots were subcultured on selection medium with 20-50 mg/l kanamycin for 3-6 months for eliminating escaped non-transformants, and then rooted on ms medium containing 25 mg/l ... | 1999 | 10589167 |
| gm corn poses little threat to monarch. | 1999 | 10585702 | |
| differential enhancement of cry2a versus cry11a yields in bacillus thuringiensis by use of the cry3a stab mrna sequence. | previously we demonstrated that the yield of cry3a (70 kda) can be increased as much as 10-fold when cry3a including its upstream stab-sd mrna stabilizing sequence is expressed in bacillus thuringiensis under the control of cyt1a promoters. to determine whether the cyt1a promoters/stab-sd combination (cyt1ap/stab) has broader applicability, we used it to synthesize two other cry endotoxins in the 70-kda mass range, cry2a and cry11a. combination of cyt1ap/stab with orfs 2 and 3 of the cry2a opero ... | 1999 | 10585556 |
| the hemolytic enterotoxin hbl is broadly distributed among species of the bacillus cereus group. | the prevalence of the hemolytic enterotoxin complex hbl was determined in all species of the bacillus cereus group with the exception of bacillus anthracis. hbla, encoding the binding subunit b, was detected by pcr and southern analysis and was confirmed by partial sequencing of 18 strains. the sequences formed two clusters, one including b. cereus and bacillus thuringiensis strains and the other one consisting of bacillus mycoides, bacillus pseudomycoides, and bacillus weihenstephanensis strain ... | 1999 | 10584001 |
| resistance in sunflower and interaction with bacillus thuringiensis for control of banded sunflower moth (lepidoptera: tortricidae). | four sunflower accessions were compared with a susceptible check, hybrid '894', in the greenhouse to determine their resistance to the banded sunflower moth, cochylis hospes walsingham, and their interaction with bacillus thuringiensis berliner variety kurstaki. antibiosis, expressed as lower larval weight, was detected in all of the accessions. in addition to being antibiotic, sunflower accession ames 3291 was antixenotic to banded sunflower moth oviposition and exhibited an additional impact o ... | 1999 | 10582050 |
| toxicity of bacillus thuringiensis beta-exotoxin to three species of fruit flies (diptera: tephritidae). | the current study describes toxic effects of the bacillus thuringiensis beta-exotoxin toward 3rd instars of 3 fruit fly species: anastrepha ludens (loew), a. obliqua (macquart), and a. serpentina (wiedemann). the beta-exotoxin was highly toxic to all 3 species tested, with lc50 values calculated as 0.641, 0.512, and 0.408 microgram/cm2 of filter paper used to expose the larvae, for a. ludens, a. obliqua, and a. serpentina, respectively. exposure to beta-exotoxin was associated with an increase i ... | 1999 | 10582044 |
| genome stability of bacillus thuringiensis subsp. israelensis isolates. | swedish soil isolates biochemically classified as bacillus thuringiensis subsp. israelensis were further examined for genetic diversity by multilocus enzyme electrophoresis (mlee), random amplified polymorphic dna analysis (rapd), pulse field gel electrophoresis (pfge), and southern blotting, and were compared with reference strains. all the tested strains belonging to the bt. israelensis serotype h14 were found to be identical, as judged from the rapd analysis. mlee analysis gave a similar resu ... | 2000 | 10568804 |
| characterization of bacillus thuringiensis ser. balearica (serotype h48) and ser. navarrensis (serotype h50): two novel serovars isolated in spain. | the novel strains of bacillus thuringiensis pm9 and na69, isolated from soil samples in spain, were classified and characterized in terms of their crystal proteins, plasmid profile, cry genes content, and their toxicological properties against several species of lepidoptera, coleoptera, and diptera. both strains share morphological and biochemical characteristics with previously described b. thuringiensis strains, although their unique h antigens identify them as two new serotypes. two new serov ... | 2000 | 10568798 |
| [the effect of a soil extract on the development of bacillus thuringiensis and on its synthesis of an insecticidal endotoxin]. | selection of effective and inexpensive nutrient medium for cultivation of entomopathogenic bacteria bacillus thuringiensis was carried out. the medium with molasses [correction of patoka], corn extract and mineral salts has been chosen. addition of a soil extract to the medium enhanced growth of microorganisms, increased the rate of culture development, the yield of spore-crystalline material and quantity of synthesized endotoxin. apparently the strengthening effect belongs to humic substances c ... | 1999 | 10565149 |
| membrane proteins of aedes aegypti larvae bind toxins cry4b and cry11a of bacillus thuringiensis ssp. israelensis. | proteins of molecular weight 65 and 62 kd and having affinity for toxins cry4b and cry11a produced by bacillus thuringiensis ssp. israelensis have been isolated from brush border membranes of aedes aegypti larvae using affinity chromatography. using a ligand blotting technique, we show that the binding of these proteins to the biotinylated toxins is reversible and that the two toxins compete for binding to the two proteins. these proteins are likely to be cry4b and cry11a toxin receptors in gut ... | 1999 | 10561564 |
| two types of entomocidal crystals of bacillus thuringiensis ssp. finitimus have the same set of unique delta-endotoxins. | the strain b-1166 differs from the other strains of bacillus thuringiensis ssp. finitimus because it has two crystal types with different localization in the sporulating cell, i.e., inside and outside of exosporium membrane. two dissociants of the strain were obtained containing only one of the crystal types. the initial strain produces at least three various delta-endotoxins (fin2, fin3, and fin5) differing from all other known entomocidal proteins; fin2 and fin3 are similar to each other but d ... | 1999 | 10561558 |
| green fluorescent protein as a marker for expression of a second gene in transgenic plants. | the use of transgenic crops has generated concerns about transgene movement to unintended hosts and the associated ecological consequences. moreover, the in-field monitoring of transgene expression is of practical concern (e.g., the underexpression of an herbicide tolerance gene in crop plants that are due to be sprayed with herbicide). a solution to these potential problems is to monitor the presence and expression of an agronomically important gene by linking it to a marker gene, such as gfp. ... | 1999 | 10545923 |
| gmo roundup. | 1999 | 10545872 | |
| facts and hypotheses. | 1999 | 10545871 | |
| refined, circular restriction map of the bacillus thuringiensis subsp. israelensis plasmid carrying the mosquito larvicidal genes. | all the genetic elements responsible for the mosquito larval toxicity of bacillus thuringiensis subsp. israelensis are located on one of its largest plasmids, nicknamed pbtoxis. two linkage groups (with sizes of about 75 and 55 kb) have previously been mapped partially with respect to saci and bamhi restriction sites (ben-dov et al., 1996), but linking them to a single circular plasmid unambiguously was impossible with the available data. to finalize the plasmid map, another rare cutting restric ... | 1999 | 10545261 |
| the cadherin-like protein is essential to specificity determination and cytotoxic action of the bacillus thuringiensis insecticidal cryiaa toxin. | the bacillus thuringiensis cryiaa toxin binds a cadherin-like protein (btr175) on the brush-border membranes of the bombyx mori midgut columnar cells, which are the targets. by introducing the btr175 gene with a baculovirus, spodoptera frugiperda sf9 cells expressed btr175 protein on the cell membrane and became susceptible to the cryiaa toxin. the toxin bound the cadherin repeat adjacent to the membrane and made a pore that passed inorganic ions, causing the cell to swell and burst. this was no ... | 1999 | 10544269 |
| partial purification and characterization of bacillus thuringiensis cry1a toxin receptor a from heliothis virescens and cloning of the corresponding cdna. | although extensively studied, the mechanism of action of insecticidal bacillus thuringiensis cry toxins remains elusive and requires further elucidation. toxin receptors in the brush border membrane demand particular attention as they presumably initiate the cascade of events leading to insect mortality after toxin activation. the 170-kda cry1ac toxin-binding aminopeptidase from the tobacco budworm (heliothis virescens) was partially purified, and its corresponding cdna was cloned. the cdna enco ... | 1999 | 10543783 |
| helix 4 of the bacillus thuringiensis cry1aa toxin lines the lumen of the ion channel. | the mode of action of bacillus thuringiensis insecticidal proteins is not well understood. based on analogies with other bacterial toxins and ion channels, we hypothesized that charged amino acids in helix 4 of the cry1aa toxin are critical for toxicity and ion channel function. using plutella xylostella as a model target, we analyzed responses to cry1aa and eight proteins with altered helix 4 residues. toxicity was abolished in five charged residue mutants (e129k, r131q, r131d, d136n, d136c), h ... | 1999 | 10542230 |
| bioassay to assess the toxicity of bacillus thuringiensis to daikon leaf beetle (coleoptera: chrysomelidae) | we developed a new method to rear daikon leaf beetles, phaedon brassicae baly (coleoptera: chrysomelidae), on a diet of cruciferae leaves in a growth chamber. eggs were stored at 4 degrees c for 30 days without significant loss of viability. a bioassay using artificial diet was developed to standardize the assessment of toxicity of a powdered crystal-spore preparation of bacillus thuringiensis strain ybt-0618 to p. brassicae larvae. when the diet containing this powder preparation was stored at ... | 1999 | 10534412 |
| lectin activity of bacillus thuringiensis parasporal inclusion proteins. | parasporal inclusion proteins from a total of 151 bacillus thuringiensis strains, consisting of 139 japanese isolates and the type strains of 12 h serovars, were screened for haemagglutination (ha) activity against sheep erythrocytes. of 58 b. thuringiensis strains with ha activity, nine strains exhibited high activity and the remaining 49 strains were moderately active. the strains with high ha activity were derived from phylloplanes and soils of five geographically different localities, and be ... | 1999 | 10518745 |
| multiple roles for tnpi recombinase in regulation of tn5401 transposition in bacillus thuringiensis. | tn5401 is a class ii transposable element derived from the gram-positive bacterium bacillus thuringiensis. the 4,837-bp transposon encodes a tn3-like transposase (tnpa) and an integrase-like recombinase (tnpi) and is notable for its unusually long 53-bp terminal inverted repeats (tirs). the tnpa and tnpi genes are transcribed from a common promoter, designated p(r), that is subject to negative regulation by tnpi. the tirs of tn5401 each contain a 38-bp sequence that can be aligned with the 38- t ... | 1999 | 10515914 |
| production of chymotrypsin-resistant bacillus thuringiensis cry2aa1 delta-endotoxin by protein engineering. | cleavage of the cry2aa1 protoxin (molecular mass, 63 kda) from bacillus thuringiensis by midgut juice of gypsy moth (lymantria dispar) larvae resulted in two major protein fragments: a 58-kda fragment which was highly toxic to the insect and a 49-kda fragment which was not toxic. in the midgut juice, the protoxin was processed into a 58-kda toxin within 1 min, but after digestion for 1 h, the 58-kda fragment was further cleaved within domain i, resulting in the protease-resistant 49-kda fragment ... | 1999 | 10508095 |
| identification of residues in domain iii of bacillus thuringiensis cry1ac toxin that affect binding and toxicity. | alanine substitution mutations in the cry1ac domain iii region, from amino acid residues 503 to 525, were constructed to study the functional role of domain iii in the toxicity and receptor binding of the protein to lymantria dispar, manduca sexta, and heliothis virescens. five sets of alanine block mutants were generated at the residues (503)ss(504), (506)nni(508), (509)qnr(511), (522)st(523), and (524)st(525). single alanine substitutions were made at the residues (509)q, (510)n, (511)r, and ( ... | 1999 | 10508083 |
| identification of bacillus thuringiensis delta-endotoxin cry1c domain iii amino acid residues involved in insect specificity. | cry1c domain iii amino acid residues involved in specificity for beet armyworm (spodoptera exigua) were identified. for this purpose, intradomain iii hybrids between cry1e (nontoxic) and cry1e-cry1c hybrid g27 (toxic) were made. crossover points of these hybrids defined six sequence blocks containing between 1 and 19 of the amino acid differences between cry1e and g27. blocks b, c, d, and e of g27 were shown to be required for optimal activity against s. exigua. block e was also required for opt ... | 1999 | 10508062 |
| [identification and characterization of strains of bacillus thuringiensis by genomic fingerprinting using biotinylated phage m13 dna]. | genomic dna of the entomopathogenic bacterium bacillus thuringiensis was analyzed by the genomic fingerprinting technique. the biotin-labeled single-stranded dna of the phage m13 was used as a marker of hypervariable sequences. a procedure for analyzing the differentiation among various bacillus thuringiensis strains was developed. characteristic patterns of fingerprints were obtained for several strains, the main representatives of subspecies that are most frequently used in the manufacture of ... | 1999 | 10505264 |
| interplant movement of heliothis virescens (lepidoptera: noctuidae) larvae in pure and mixed plantings of cotton with and without expression of the cry1ac delta-endotoxin protein of bacillus thuringiensis berliner. | laboratory and field studies were conducted during 1993 and 1994 to quantify interplant movement of heliothis virescens (f.) larvae in pure and mixed plantings of cotton, gossypium hirsutum l., with ('event 531') and without ('coker 312') the expression of cry1ac delta-endotoxin protein of bacillus thuringiensis berliner. field studies were conducted with neonate, 4-, and 7-d-old larvae placed on 3-plant experimental units and observed at 24, 48, 72, and 96 h after inoculation of larvae. combini ... | 1999 | 10504897 |
| green-tissue-specific expression of a reconstructed cry1c gene encoding the active fragment of bacillus thuringiensis delta-endotoxin in haploid tobacco plants conferring resistance to spodoptera litura. | the dna sequence of a truncated cry1c gene encoding the active fragment of bacillus thuringiensis (bt) delta-endotoxin was fully reconstructed by introduction of silent mutations. each of the truncated wild type and the synthetic genes encoding the active fragment of the protoxin was introduced into haploid tobacco plants under the control of the rbcs promoter. to facilitate selection of transgenic tobacco plants with high insecticidal activity, a fusion gene encoding both rat cyp1a1 cytochrome ... | 1999 | 10501003 |
| biotech companies must get back to basics to weigh up risks. | 1999 | 10499565 | |
| analysis of mutations in the pore-forming region essential for insecticidal activity of a bacillus thuringiensis delta-endotoxin. | the bacillus thuringiensis insecticidal delta-endotoxins have a three-domain structure, with the seven amphipathic helices which comprise domain i being essential for toxicity. to better define the function of these helices in membrane insertion and toxicity, either site-directed or random mutagenesis of two regions was performed. thirty-nucleotide segments in the b. thuringiensis cry1ac1 gene, encoding parts of helix alpha4 and the loop connecting helices alpha4 and alpha5, were randomly mutage ... | 1999 | 10498724 |
| effect of bacillus thuringiensis ssp. israelensis on the development of plasmodium gallinaceum in aedes aegypti (diptera: culicidae). | adult, female aedes aegypti, some of which had survived a sublethal dose (lc50) of bacillus thuringiensis ssp. israelensis (bti) as larvae, were fed on chickens with gametocytaemia of plasmodium gallinaceum. parasite development was monitored by dissecting samples of the mosquitoes immediately after the feed and on days 1, 7 and 9 post-feed, to check for the presence of gametocytes, ookinetes, oocysts and sporozoites, respectively. as the proportions of batches of fed mosquitoes found positive f ... | 1999 | 10492676 |
| insecticidal activity of strains of bacillus thuringiensis on larvae and adults of bactrocera oleae gmelin (dipt. tephritidae). | the olive fly, bactrocera oleae, is the key pest on olives in the mediterranean area. the pest can destroy, in some cases, up to 70% of the olive production. its control relies mainly on chemical treatments, sometimes applied by aircraft over vast areas, with their subsequent ecological and toxicological side effects. bacillus thuringiensis is a spore-forming soil bacterium which produces a protein crystal toxic to some insects, including the orders of lepidoptera, diptera, and coleoptera and ot ... | 1999 | 10486224 |
| amino acid substitution in alpha-helix 7 of cry1ac delta-endotoxin of bacillus thuringiensis leads to enhanced toxicity to helicoverpa armigera hubner. | insecticidal proteins or delta-endotoxins of bacillus thuringiensis are highly toxic to a wide range of agronomically important pests. the toxins are formed of three structural domains. the n-terminal domain is a bundle of eight alpha-helices and is implicated in pore formation in insect midgut epithelial membranes. all the delta-endotoxins share a common hydrophobic motif of eight amino acids in alpha-helix 7. a similar motif is also present in fragment b of diphtheria toxin (dt). site-directed ... | 1999 | 10481060 |
| development of the first black fly (diptera: simuliidae) management program in argentina and comparison with other programs. | in response to increasing pest populations of black flies, the government of argentina initiated a pilot program to evaluate the effectiveness of larval control in the irrigation system of the negro river valley, an 18,240-km2 area in patagonia. the extensive system of irrigation canals, drainage ditches, and natural waterways not only provides water for agriculture and general habitation but also affords habitat for immature black flies. three species (simulium bonaerense, simulium wolffhuegeli ... | 1999 | 10480133 |
| residual activity of bacillus thuringiensis serovars medellin and jegathesan on culex pipiens and aedes aegypti larvae. | bacillus thuringiensis serovar medellin strain 163-131 and bacillus thuringiensis serovar jegathesan (b.t.jeg.) strain 367 are very toxic to mosquito larvae. however, they are 10 times less toxic than bacillus thuringiensis var. israelensis (b.t.i.) to mosquito larvae under laboratory conditions. lyophilized powders were produced from these strains and their toxicities were compared to that of powder produced from the b.t.i. strain. larvicidal activity was titrated using aedes aegypti (bora-bora ... | 1999 | 10480130 |
| field evaluation of new water-dispersible granular formulations of bacillus thuringiensis ssp. israelensis and bacillus sphaericus against culex mosquitoes in microcosms. | a variety of formulations of bacillus thuringiensis var. israelensis de barjac (b.t.i.) and bacillus sphaericus neide (b.s.) have been studied for mosquito control under laboratory and field conditions. high efficacy, specificity, low risk of development of resistance, long shelf-life, and transportability, as well as the safety to nontarget organisms of these 2 microbial agents have been well documented. some of the currently available formulations of b.t.i. and b.s. have low potency per unit m ... | 1999 | 10480128 |
| activity spectra of bacillus thuringiensis delta-endotoxins against eight insect cell lines. | eight continuous insect cell lines were tested for susceptibility to the delta-endotoxins of several lepidopteran-active strains and cloned-gene products of bacillus thuringiensis. the assays were performed on cells suspended in agarose gel, which allowed the toxins activated at ph 10.5 to be applied directly in a high-ph buffer without causing solvent toxicity to the cells. the responses of the cell lines to the various toxins produced activity spectra that were used to identify functionally si ... | 1999 | 10475277 |
| development and field performance of a broad-spectrum nonviable asporogenic recombinant strain of bacillus thuringiensis with greater potency and uv resistance. | the main problems with bacillus thuringiensis products for pest control are their often narrow activity spectrum, high sensitivity to uv degradation, and low cost effectiveness (high potency required). we constructed a sporulation-deficient sigk(-) b. thuringiensis strain that expressed a chimeric cry1c/ab gene, the product of which had high activity against various lepidopteran pests, including spodoptera littoralis (egyptian cotton leaf worm) and spodoptera exigua (lesser [beet] armyworm), whi ... | 1999 | 10473413 |
| false reports and the ears of men. | 1999 | 10471903 | |
| resistance to bacillus thuringiensis cry1ac toxin in three strains of heliothis virescens: proteolytic and sem study of the larval midgut | in a previous study, we demonstrated that resistance to bacillus thuringiensis toxins in heliothis virescens might be related to differences in the composition of the proteolytic extracts from insect midgut. there, we found specific proteolytic bands present in the gut extracts of the resistant strain and absent from the susceptible one. here we report related facts using a new resistant strain (kcb) and a cross between the two strains used in our previous study. as would be expected, no quantit ... | 1999 | 10467056 |
| protease interactions with bacillus thuringiensis insecticidal toxins | the microbe bacillus thuringiensis (bt) produces crystals that contain insecticidal crystal proteins (icps) used to control many major pests. icps are degraded by proteases from a variety of sources, including those endogenous to the bacterium, those purified from animals and plants, or those found in insects. proteases in the bacterium function in protein metabolism during sporulation; in some cases they hydrolyze icps. insect proteases are implicated in bt toxin specificity, mode of action and ... | 1999 | 10467052 |
| [the construction and use of inosine-containing primers for searching for and identifying the genes of insecticidal crystal proteins in bacillus thuringiensis]. | the specific to 3 types of cry genes primers containing inosine were constructed to find crystal insecticidal protein bacillus thuringiensis genes using pcr. a number of new b. thuringiensis strains isolated in ukraine were investigated using these pcr primers. as a results, cry genes were found, some of them were identified and demonstrated high homology to cry1ba2 and cry1bc genes. | 1999 | 10465846 |
| a new strain of bacillus thuringiensis serovar israelensis very active against blackfly larvae. | 1999 | 10464418 | |
| field studies with the bacterial larvicide inpalbac for simulium spp. control in rio grande do sul, brazil. | 1999 | 10464417 | |
| a comparison of the kinetics of plasmid transfer in the conjugation systems encoded by the f plasmid from escherichia coli and plasmid pcf10 from enterococcus faecalis. | quantitative measurements of horizontal dna transfer are critical if one wishes to address questions relating to ecology, evolution and the safe use of recombinant bacteria. traditionally, the efficiency of a conjugation system has been described by its transfer frequency. however, transfer frequencies can be determined in many ways and may be sensitive to physical, chemical and biological conditions. in this study the authors have used the mechanistic similarity between bacterial conjugation an ... | 1999 | 10463166 |
| inorganic phosphate regulates cryiva protoxin expression in bacillus thuringiensis israelensis. | the role of nutritional factors during cryiva protoxin expression in bacillus thuringiensis israelensis (bti) has been investigated. inorganic phosphate (pi) was found to stimulate 135 kd protoxin synthesis by bti cells. there was a corresponding increase in the cryiva specific mrna in the presence of pi. inorganic phosphate inhibited hpr kinase but activated hpr phosphatase, the two enzymes responsible for regulating the concentration of phosphorylated hpr in the cell. addition of protein phosp ... | 1999 | 10462480 |
| antibiotic mic/mbc analysis of bacillus-based commercial insecticides: use of bioreduction and dna-based assays. | minimum inhibitory concentration (mic) assays, monitored by colony counts, growth (turbidity) and bioreduction of non-toxic xtt [2,3-bis (2-methoxy-4-nitro-5-sulphophenyl)-2h-tetrazolium-5-carboxanilide, inner salt], were used to assess the performance of several types of antibiotics against: (1) commercial bt products made from scale-up sporulation phase cultures of bacillus thuringiensis subsp israelensis (bti) and subsp kurstaki (btk); (2) vegetative cells derived from these bt products; and ... | 1999 | 10455482 |
| development time and resistance to bt crops. | 1999 | 10448853 | |
| bollworms, genes and ecologists. | 1999 | 10448848 |