| metalloprotease from bacillus thuringiensis. | bacillus thuringiensis var. kurstaki was shown to produce an extracellular, metal chelator-sensitive protease during the early stages of sporulation. protease production in nutrient broth was dependent upon supplementation with mn2+ or ca2. the addition of ca24 was required for enzyme stabilization... | 1975 | 241290 |
| purification of the insecticidal toxin from the parasporal crystal of bacillus thuringiensis subsp. kurstaki. | | 1979 | 526269 |
| design and use of synthetic oligonucleotide probes in the cloning of delta-endotoxin genes from bacillus thuringiensis. | a detailed protocol is described for the design and use of synthetic oligonucleotide probes for screening dna libraries from bacillus thuringiensis var. kurstaki (strain hd191) for copies of the gene (tox) encoding the insecticidal delta-endotoxin. two homologous tox genes were identified in this organism; one of these was located on a 75-kb plasmid and the other on a second large plasmid or the bacterial chromosome. a tox gene was isolated as a 6.5-kb hindiii fragment of b. thuringiensis plasmi ... | 1991 | 1369333 |
| isolation and sequence of a 2-kbp miniplasmid from bacillus thuringiensis var. kurstaki hd-3a3b: relationship with miniplasmids of other b. thuringiensis strains. | the miniplasmid profiles of 18 bacillus thuringiensis strains belonging to 8 different serotypes were determined using an alkaline hydrolysis method for isolation of low molecular mass plasmids. nearly all the strains contained covalently closed circular (ccc) dna species ranging from 2 to 5 species per strain and from 1.5 to 10.5 kbp in size (values corresponding to ccc forms). a 2-kbp plasmid from b. thuringiensis var. kurstaki hd-3a3b futura strain was used in southern hybridization experimen ... | 1992 | 1426990 |
| [influence of carbon sources on the biological activity and morphology of bacillus thuringiensis parasporal crystals]. | the influence of the carbon source on biological activity and morphological properties of the parasporal crystals of bacillus thuringiensis subsp. kurstaki cultivated on three different media has been studied. biological activity of delta-endotoxins contained in crystals was tested according to their impact on insects and microorganisms. variations in carbon sources composition resulted in changes of biological activity and morphology of crystals, caused by alterations in synthesis rate of vario ... | 1992 | 1474939 |
| arabidopsis thaliana small subunit leader and transit peptide enhance the expression of bacillus thuringiensis proteins in transgenic plants. | the expression of the modified gene for a truncated form of the cryia(c) gene, encoding the insecticidal portion of the lepidopteran-active cryia(c) protein from bacillus thuringiensis var. kurstaki (b.t.k.) hd73, under control of the arabidopsis thaliana ribulose-1,5-bisphosphate carboxylase (rubisco) small subunit ats1a promoter with and without its associated transit peptide was analyzed in transgenic tobacco plants. examination of leaf tissue revealed that the ats1a promoter with its transit ... | 1992 | 1515613 |
| bacillus thuringiensis crystal protein: effect of chemical modification of the cysteine and lysine residues. | the 16 cysteine residues of reduced protoxin from bacillus thuringiensis subsp. kurstaki hd-73 can be quantitatively reacted with: (a) iodoacetic acid, to give carboxymethyl protoxin; (b) iodoacetamide, giving carbaminomethyl protoxin and (c) n-(beta-iodoethyl)trifluoroacetamide to give aminoethyl protoxin. the carboxymethyl derivative was found to be significantly more soluble at neutral ph values where both the native protoxin and the carbaminomethyl derivative exhibit low solubilities. at the ... | 1992 | 1541850 |
| nucleotide sequence of gene cryiiid encoding a novel coleopteran-active crystal protein from strain bti109p of bacillus thuringiensis subsp. kurstaki. | the nucleotide sequence of a novel insecticidal crystal protein(cry)-encoding gene from a bacillus thuringiensis serotype kurstaki isolate is described. the gene is related to the known coleopteran-active cryiii genes and encodes a cryiiid that is much more active against colorado potato beetle than other cryiii. | 1992 | 1544571 |
| comparative toxicity of the hd-1 and nrd-12 strains of bacillus thuringiensis subsp. kurstaki to defoliating forest lepidoptera. | insecticidal activities of sporulated cultures of the hd-1 and nrd-12 strains of bacillus thuringiensis subsp. kurstaki were compared against four species of defoliating forest lepidopterans in diet-incorporation assays. there was no difference in lc50 between the two strains to larvae of spruce budworm (choristoneura fumiferana), gypsy moth (lymantria dispar), eastern hemlock looper (lambdina fiscellaria fiscellaria), and whitemarked tussock moth (orgyia leucostigma), whether expressed as total ... | 1992 | 1607666 |
| lethal and sublethal effects of bacillus thuringiensis var. kurstaki on aquatic insects in laboratory bioassays and outdoor stream channels. | | 1992 | 1611248 |
| identification and characterization of heliothis virescens midgut membrane proteins binding bacillus thuringiensis delta-endotoxins. | to investigate the specificity of bacillus thuringiensis var. kurstaki strain hd1 insecticidal crystal proteins (icp), we used membrane preparations obtained from the midgut of heliothis virescens larvae to perform separate ligand-blot experiments with the three activated cryia toxins. the cryia(a) and the cryia(b) toxins bind the same 170-kda protein, but most likely at two different binding sites. the cryia(c) toxin binds two proteins of molecular masses 140 kda and 120 kda. we also demonstrat ... | 1991 | 1662137 |
| isolation of the second bacillus thuringiensis rna polymerase that transcribes from a crystal protein gene promoter. | a crystal protein gene of bacillus thuringiensis subsp. kurstaki hd-1-dipel is transcribed in vivo from two overlapping promoters that are activated at different times during sporulation. we reported earlier (k. l. brown and h. r. whiteley, proc. natl. acad. sci. usa 85:4166-4170, 1988) that an rna polymerase containing a sigma subunit with an apparent mr of 35,000 can transcribe in vitro from the promoter utilized from early to midsporulation. we now report the isolation of an rna polymerase co ... | 1990 | 1701426 |
| isolation and cloning of bacillus thuringiensis var kurstaki hd73 toxin gene and construction of a chimaeric gene for expression in plants. | necessity for the production of transgenic crop plants of india, capable of expression of insecticidal bt protein in plant to combat lepidopteran pest damage has been strongly felt. bacillus thuringiensis kurstaki hd73 crystal protein coded by cryia(c)73 gene has been found to be sufficiently effective against the major pests of jute and chickpea. an attempt to isolate the gene and make its use in a chimaeric gene construct for expression in plant was carried out. the plasmid cryia(c)73 gene was ... | 1991 | 1816076 |
| characterization and sequence analysis of a small plasmid from bacillus thuringiensis var. kurstaki strain hd1-dipel. | the complete nucleotide sequence of a small (2.055 kb) plasmid phd2 from bacillus thuringiensis var. kurstaki strain hd1-dipel was obtained. the sequence encoded two open reading frames (orfs) which corresponded to polypeptides of mr 26,447 and 9122. comparison of the sequence with those obtained for other plasmids from gram-positive organisms suggested that phd2 may belong to the extensive and highly interrelated family of plasmids exhibiting replication via a ssdna intermediate: a putative nic ... | 1991 | 1857751 |
| two new isolates of bacillus thuringiensis pathogenic to spodoptera litura. | both the standard bacillus thuringiensis kurstaki (hd-1) and the formulated commercial product resulted from this strain have shown limited pathogenicity against the tobacco cutworm (spodoptera litura). however, two new isolates of bacillus thuringiensis (k-2074 and k-2178) isolated from taiwan have been identified through an active screening program to be highly pathogenic against the tobacco cutworm. in this paper, we present results of characterization and the pathogenicity of these two new i ... | 1991 | 1885923 |
| identity of hemolysins produced by bacillus thuringiensis and bacillus cereus. | a hemolysin (bt-hemolysin) produced by bacillus thuringiensis var. kurstaki hd-1 producing crystalline toxin(s) was purified by successive treatments of ammonium sulfate (45-65%) and column chromatography using deae-cellulose, sephadex g-75 and kb-002 (a hydroxyapatite column for fast protein liquid chromatography). a hemolysin (bc-hemolysin) produced by b. cereus hg-6a was also purified by the same procedure. the purified bt-hemolysin and bc-hemolysin, both of which are thiol-activated hemolysi ... | 1991 | 1905656 |
| transduction of certain genes by an autonomously replicating bacillus thuringiensis phage. | a derivative of bacillus thuringiensis subsp. kurstaki hd1 (hd1-9) released transducing phage (tp21) from late exponential cultures. three of seven markers tested were transduced into bacillus cereus, but only two of these (cysc and trpb/f) were transduced at a frequency of more than 100 times the reversion rates. a limited transduction capacity was given further support in that few chromosomal markers were carried in the hd1-9 lysate, as demonstrated by southern hybridization. restriction fragm ... | 1991 | 2059027 |
| construction of genetically engineered baculovirus insecticides containing the bacillus thuringiensis subsp. kurstaki hd-73 delta endotoxin. | the delta-endotoxin gene from bacillus thuringiensis subsp. kurstaki hd-73 was inserted into autographa californica nuclear polyhedrosis virus (acmnpv) using two transfer vector systems. in the first, the delta-endotoxin gene was placed under the control of the polyhedrin gene promoter in lieu of the polyhedrin coding sequences, thus deriving a polyhedrin-negative virus. in the second, it was inserted under the control of a copy of the acmnpv p10 promoter positioned upstream of the polyhedrin ge ... | 1990 | 2165136 |
| light microscope immunolocation of bacillus thuringiensis kurstaki delta-endotoxin in the midgut and malpighian tubules of the tobacco budworm, heliothis virescens. | light microscope immunofluorescence was used to localize the membrane binding of bacillus thuringiensis kurstaki 63-kda delta-endotoxin in heliothis virescens midgut and malpighian tubules. staining was observed along all exposed mucosal (apical microvillar) plasma membranes. interpretation of the serosal (basal) plasma membrane staining was complicated because the basal lamina also stained. the results suggest that the toxin binds to all exposed plasma membranes without apparent specificity for ... | 1990 | 2165507 |
| location of the dipteran specificity region in a lepidopteran-dipteran crystal protein from bacillus thuringiensis. | two highly related crystal protein genes from bacillus thuringiensis subsp. kurstaki hd-1, designated cryiia and cryiib (previously named cryb1 and cryb2, respectively), were used to study host range specificity. their respective gene products are 87% identical but exhibit different toxicity spectra; cryiia is toxic to both mosquito and tobacco hornworm larvae, whereas cryiib is toxic only to the latter. hybrids of the cryiia and cryiib genes were generated, and their resultant gene products wer ... | 1990 | 2345127 |
| public health implications of the microbial pesticide bacillus thuringiensis: an epidemiological study, oregon, 1985-86. | bacillus thuringiensis var. kurstaki (b.t.-k) is a microbial pesticide which has been widely used for over 30 years. its safety for a human population living in sprayed areas has never been tested. surveillance for human infections caused by b.t.-k among lane county, oregon residents was conducted during two seasons of aerial b.t.-k spraying for gypsy moth control. bacillus isolates from cultures obtained for routine clinical purposes were tested for presence of bacillus thuringiensis (b.t.). de ... | 1990 | 2356910 |
| simple method for the isolation of the antilepidopteran toxin from bacillus thuringiensis subsp. kurstaki. | a protein with a molecular mass of 66 kda was isolated by a simple, rapid, and inexpensive method, using 3-n-morpholinopropanesulfonic acid, potassium thiocyanate, and dithiothreitol, from a mixture of spores, parasporal crystals, and cell debris of bacillus thuringiensis subsp. kurstaki. the protein was active against the third instar larvae of trichoplusia ni, was soluble in 19 mm na2co3, and was characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and confirmed as the in ... | 1990 | 2360990 |
| electron probe x-ray microanalysis of the effects of bacillus thuringiensis var kurstaki crystal protein insecticide on ions in an electrogenic k+-transporting epithelium of the larval midgut in the lepidopteran, manduca sexta, in vitro. | an alkaline hydrolysate of bacillus thuringiensis var kurstaki hd1 (btk) parasporal crystals was administered at 25 micrograms ml-1 (f.c.) to isolated, short-circuited, midguts of tobacco hornworm (manduca sexta) larvae. the short-circuit current (s.c.c.), a precise measure of k+ active transport, was inhibited by 78% in 10 min in btk-treated midguts as compared to controls. the elemental concentrations of k, together with na, mg, p, s, cl and ca, as well as the water content, were determined by ... | 1985 | 2411741 |
| accumulation of the insecticidal crystal protein of bacillus thuringiensis subsp. kurstaki in post-exponential-phase bacillus subtilis. | a gene from bacillus thuringiensis subsp. kurstaki that codes for a lepidoptera-specific insecticidal toxin (delta-endotoxin) was engineered for expression in bacillus subtilis. a low-copy-number plasmid vector that replicates in escherichia coli and b. subtilis was constructed to transform b. subtilis with gene fusions first isolated and characterized in e. coli. naturally occurring promoter sequences from b. subtilis (43, veg, ctc, and spovg) were inserted upstream from the plasmid-borne struc ... | 1989 | 2508556 |
| protein phosphorylation in bacillus thuringiensis during growth and delta-endotoxin production. | at least 14 phosphopolypeptides in which the phosphate groups were present as mono-esters were detected by pulse labelling of bacillus thuringiensis subsp. kurstaki hd-1-dipel with [32p]orthophosphate at different stages of growth and differentiation. marked changes in the profile of phosphopolypeptides were observed primarily during the late exponential phase of growth. several phosphopolypeptides co-purified with the endotoxin crystal of this subspecies and the phosphoamino acid residue of the ... | 1988 | 2855529 |
| two highly related insecticidal crystal proteins of bacillus thuringiensis subsp. kurstaki possess different host range specificities. | two genes encoding insecticidal crystal proteins from bacillus thuringiensis subsp. kurstaki hd-1 were cloned and sequenced. both genes, designated cryb1 and cryb2, encode polypeptides of 633 amino acids having a molecular mass of ca. 71 kilodaltons (kda). despite the fact that these two proteins display 87% identity in amino acid sequence, they exhibit different toxin specificities. the cryb1 gene product is toxic to both dipteran (aedes aegypti) and lepidopteran (manduca sexta) larvae, whereas ... | 1989 | 2914879 |
| structural similarity between the lepidoptera- and diptera-specific insecticidal endotoxin genes of bacillus thuringiensis subsp. "kurstaki" and "israelensis". | a gene from bacillus thuringiensis subsp. "israelensis" was cloned from the large plasmids of this subspecies and was shown to code for a mosquitocidal polypeptide. the gene could be expressed in either escherichia coli, bacillus subtilis, or b. thuringiensis subsp. "israelensis" to produce the larvicidal activity. similarly, a lepidoptera-specific toxin gene from b. thuringiensis subsp. "kurstaki" was also cloned and expressed in e. coli and b. subtilis. both cloned genes were sequenced and sub ... | 1986 | 3011746 |
| characterization and partial purification of a plasma membrane receptor for bacillus thuringiensis var. kurstaki lepidopteran-specific delta-endotoxin. | the lepidopteran-specific p1 delta-endotoxin of bacillus thuringiensis var. kurstaki hd-1 was activated in vitro using insect gut proteases and found to be highly specific for the lepidopteran cell line choristoneura fumiferana cf1 among a wide range of lepidopteran and dipteran cell lines tested. the toxicity of p1 against cf1 cells is inhibited by n-acetylgalactosamine (galnac), and the lectins soybean agglutinin (sba) and wheat-germ agglutinin. protein blotting was used to identify a glycopro ... | 1986 | 3027110 |
| [toxic effects of bacillus thuringiensis var. kurstaki to the immature stage of aedes aegypti]. | | 1988 | 3244164 |
| isolation of a bacillus thuringiensis rna polymerase capable of transcribing crystal protein genes. | we report the isolation of an rna polymerase from sporulating cells of bacillus thuringiensis subsp. kurstaki hd-1-dipel that directs transcription from the promoter region of an insecticidal crystal protein gene. the core components of this rna polymerase are associated with a polypeptide that has an apparent mass of 35 kda. neither rna polymerase holoenzyme isolated from vegetative b. thuringiensis, nor the core derived from this enzyme, is capable of transcribing from the crystal protein gene ... | 1988 | 3380786 |
| integration of the delta-endotoxin gene of bacillus thuringiensis into the chromosome of root-colonizing strains of pseudomonads using tn5. | the delta-endotoxin gene (tox) from bacillus thuringiensis subsp. kurstaki hd-1 was cloned into tn5 and the resulting tn5-tox element transposed from a vector plasmid into the chromosome of six corn-root-colonizing strains of pseudomonas fluorescens and agrobacterium radiobacter. chromosomal integration of the tox gene maximized stability and minimized the potential for horizontal transfer of the tox gene to other bacterial species. expression of the tox gene was demonstrated by western blot ana ... | 1986 | 3026918 |
| facile autoplast generation and transformation in bacillus thuringiensis subsp. kurstaki. | we describe a method for maximizing the rate of conversion of bacillus thuringiensis subsp. kurstaki vegetative cells to osmotically fragile forms in the absence of exogenously added enzymes. optimal generation of autoplasts occurred in 50 mm sodium acetate buffer (ph 7.0) at 37 degrees c with 10% (wt/vol) polyethylene glycol as an osmotic stabilizer. the maximum autolytic rate resulted in a conversion of greater than 90% of bacilli to spherical autoplasts in 6 min. autoplasts regained bacillary ... | 1987 | 3680166 |
| susceptibility of poultry biting lice (mallophaga) to dipel and bacilan (bacillus thuringiensis). | dipel (abbott laboratories, n. chicago, u.s.a.) and bacilan (ppr, wałcz, poland), commercial preparation of bacillus thuringiensis var. kurstaki, containing 16,000 iu/mg were tested in vitro on menopon gallinae (l.) and eomenacanthus stramineus (nitzsch). the insects were placed in feathers, in petri plates, and sprayed with 0.25, 0.5, 0.75, 1, 2, 4 and 10% solutions of insecticides. each concentration was tested on a group of 10 insects, in three replications. the viability was observed after 1 ... | 1986 | 3717688 |
| tn5-mediated integration of the delta-endotoxin gene from bacillus thuringiensis into the chromosome of root-colonizing pseudomonads. | gene replacement mediated by tn5 sequences was used to integrate the bacillus thuringiensis subsp. kurstaki hd-1 delta-endotoxin gene (tox) into the chromosome of two corn root-colonizing strains of pseudomonas fluorescens. a tn5 transposase deletion element containing the tox gene (delta tn5-tox) was substituted for a tn5 element previously present in the p. fluorescens chromosome. two classes of delta tn5-tox elements were made. the first class encodes kanamycin resistance in addition to the t ... | 1986 | 3023294 |
| vegetative expression of the delta-endotoxin genes of bacillus thuringiensis subsp. kurstaki in bacillus subtilis. | bacillus thuringiensis subsp. kurstaki total dna was digested with bglii and cloned into the bamhi site of plasmid puc9 in escherichia coli. a recombinant plasmid, phbhe, expressed a protein of 135,000 daltons that was toxic to caterpillars. a hincii-smai double digest of phbhe was then ligated to bglii-cut plasmid pbd64 and introduced into bacillus subtilis by transformation. the transformants were identified by colony hybridization and confirmed by southern blot hybridization. a 135,000-dalton ... | 1986 | 3007434 |
| characterized full-length and truncated plasmid clones of the crystal protein of bacillus thuringiensis subsp. kurstaki hd-73 and their toxicity to manduca sexta. | bacillus thuringiensis subsp. kurstaki hd-73 produces a crystal protein which is lethal to many lepidopteran larvae. the gene encoding this crystal protein has been isolated from a 75-kb plasmid and engineered into a recombinant escherichia coli plasmid for analysis. the complete nucleotide sequences of the coding region and 387-bp 5' and 376-bp 3' to the coding region have been determined. the 3537-bp of the coding region specify a protein of mr 133 330. the full-length gene and several 3' -tru ... | 1985 | 3000881 |
| degradation of the parasporal crystal produced by bacillus thuringiensis var. kurstaki. | | 1974 | 4443610 |
| factors influencing lethality of bacillus thuringiensis kurstaki toxin for eggs and larvae of trichostrongylus colubriformis (nematoda). | a toxin from bacillus thuringiensis kurstaki was lethal to eggs and first- and second-stage larvae of the ruminant nematode trichostrongylus colubriformis. sheathed and exsheathed third-stage larvae were also killed by the toxin. however, susceptibility of the ova to the toxin decreased after several hours of development. heating at 65 c for 1 hr or freezing at 0 c for 3 mo did not affect stability of the toxin. ovicidal activity of the toxin was not altered by treatment with 13 microbial or mam ... | 1989 | 2926587 |
| gene dosage effect on the expression of the delta-endotoxin genes of bacillus thuringiensis subsp. kurstaki in bacillus subtilis and bacillus megaterium. | significant differences in expression of the delta-endotoxin genes crya1 and crya2 of bacillus thuringiensis subsp. kurstaki were observed in b. subtilis and b. megaterium. the crya1 gene was expressed when present on a high-copy-number (hcn) vector in b. megaterium but not in b. subtilis. the crya2 gene was expressed in both hosts, but at a higher level in b. megaterium. expression of the crya2 gene in b. megaterium was better from a hcn vector than from a low copy number vector. inhibition of ... | 1989 | 2550328 |
| cloning and localization of the lepidopteran protoxin gene of bacillus thuringiensis subsp. kurstaki. | bacillus thuringiensis subsp. kurstaki produces a proteinaceous crystalline inclusion that is toxic for lepidopteran larvae. there are several size classes of plasmids in this organism and the presence of one or more has been correlated with production of this protein, defined as a protoxin. dna fragments of b. thuringiensis subsp. kurstaki, obtained by ecori digestion, were cloned into the vector charon 4a. recombinant phage were screened immunologically for the production of protoxin. cells in ... | 1982 | 6310560 |
| facile preparation and characterization of the toxin from bacillus thuringiensis var. kurstaki. | we report a simple three-step method of generating a homogeneous toxic fragment (toxin) in high yield from b. thuringiensis var. kurstaki. purified crystals were digested with trypsin at ph 10.5, followed by (nh4)2so4 precipitation and dialysis. for the hd73 strain the preparation is toxic to eastern-spruce-budworm (choristoneura fuminiferana) larvae. it gives a single 66 kda band on polyacrylamide-gel electrophoresis and a single band with an isoelectric point of 5.5 on an isoelectric-focusing ... | 1989 | 2549961 |
| toxicity to spodoptera exigua and trichoplusia ni of individual p1 protoxins and sporulated cultures of bacillus thuringiensis subsp. kurstaki hd-1 and nrd-12. | the toxicities to neonate spodoptera exigua and trichoplusia ni of lyophilized powders obtained from sporulated liquid cultures (referred to as sporulated cultures) and escherichia coli-expressed p1 [cryia(a) cryia(b) cryia(c)] protoxins from three-gene strains of nrd-12 and hd-1 of bacillus thuringiensis subsp. kurstaki were determined by using diet incorporation bioassays. although sporulated cultures from both strains were more toxic to t. ni than s. exigua, there were no differences in toxic ... | 1990 | 2403254 |
| enhancement of bacillus thuringiensis subsp. kurstaki toxin activity by cell lysates. | | 1990 | 2351846 |
| secondary structure of the entomocidal toxin from bacillus thuringiensis subsp. kurstaki hd-73. | the secondary structure of the toxin from bacillus thuringiensis subsp. kurstaki (btk) hd-73 was estimated by raman, infrared, and circular dichroism spectroscopy, and by predictive methods. circular dichroism and infrared spectroscopy gave an estimate of 33-40% alpha-helix, whereas raman and predictive methods gave approximately 20%. raman and circular dichroism spectra, as well as predictive methods, indicated that the toxin contains 32-40% beta-sheet structure, whereas infrared spectroscopy g ... | 1990 | 2340079 |
| relationship of the syntheses of spore coat protein and parasporal crystal protein in bacillus thuringiensis. | two major classes of polypeptides were extracted from the spore surface of bacillus thuringiensis subsp. kurstaki: the 134,000-dalton protoxin that is the major component of the crystalline inclusion and spore coat polypeptides very similar to those found on bacillus cereus spores. the quantity of spore coat polypeptides produced was reduced when compared with that produced by certain acrystalliferous mutants or by b. thuringiensis subsp. israelensis. the latter organism produced an inclusion to ... | 1982 | 7085565 |
| relative activity of bacillus thuringiensis var. kurstaki and b. thuringiensis var. israelensis against larvae of aedes aegypti, culex quinquefasciatus, trichoplusia ni, heliothis zea, and heliothis virescens. | | 1981 | 7320315 |
| folding and unfolding of the protoxin from bacillus thuringiensis: evidence that the toxic moiety is present in an active conformation. | the action of trypsin or papain on the 130-kda crystal protein (protoxin) from bacillus thuringiensis subsp. kurstaki hd-73 yields a 67-kda proteinase-resistant toxic fragment (toxin) which is derived from the n-terminal half of the molecule. sensitivity to proteolysis and fluorescence emission spectroscopy showed that the toxin unfolded to a much greater extent in 6 m guanidinium chloride (guhcl) than in 8 m urea. protoxin also unfolded extensively in 6 m guhcl, whereas in 8 m urea only the c-t ... | 1990 | 2271692 |
| comparison of toxin overlay and solid-phase binding assays to identify diverse cryia(c) toxin-binding proteins in heliothis virescens midgut. | the binding proteins, or receptors, for insecticidal bacillus thuringiensis subsp. kurstaki delta-endotoxins are located in the brush border membranes of susceptible insect midguts. the interaction of one of these toxins, cryia(c), with proteins isolated from heliothis virescens larval midguts was investigated. to facilitate the identification of solubilized putative toxin-binding proteins, a solid-phase binding assay was developed and compared with toxin overlay assays. the overlay assays demon ... | 1995 | 7618886 |
| sprayable self-encapsulating starch formulations for bacillus thuringiensis. | under glasshouse conditions, various cornstarches and adjuvants were examined as encapsulating agents in sprayable formulations for bacillus thuringiensis subsp. kurstaki berliner. when these materials were suspended in water and tested for physical factors such as viscosity, clumping, and retention on plant surfaces, a range of responses was observed. all formulations tested had acceptable viscosity, but some formulations clumped. when applied to cotton leaves, certain formulations remained les ... | 1990 | 2258512 |
| unusual proteolysis of the protoxin and toxin from bacillus thuringiensis. structural implications. | trypsin is shown to generate an insecticidal toxin from the 130-kda protoxin of bacillus thuringiensis subsp. kurstaki hd-73 by an unusual proteolytic process. seven specific cleavages are shown to occur in an ordered sequence starting at the c-terminus of the protoxin and proceeding toward the n-terminal region. at each step, c-terminal fragments of approximately 10 kda are produced and rapidly proteolyzed to small peptides. the sequential proteolysis ends with a 67-kda toxin which is resistant ... | 1990 | 2190826 |
| comparative analysis of the individual protoxin components in p1 crystals of bacillus thuringiensis subsp. kurstaki isolates nrd-12 and hd-1. | two commercially important strains (nrd-12 and hd-1) of the entomopathogenic bacterium bacillus thuringiensis subsp. kurstaki each contain three genes of partially identical sequence coding for three classes of 130-135 kda protoxins (termed the 4.5, 5.3 and 6.6 protoxins) that display toxicity towards various lepidopteran larvae. these gene products combine to form the intracellular bipyramidal p1 crystal. each of the genes from both strains was cloned and expressed in escherichia coli. analysis ... | 1990 | 2167072 |
| photoprotection of bacillus thuringiensis kurstaki from ultraviolet irradiation. | irradiation of bacillus thuringiensis var. kurstaki hd1 at 300-350 nm for up to 12 hr using a photochemical reactor results in a rapid loss of its toxicity to larvae of heliothis armigera. photoprotection of the toxic component was obtained by adsorption of cationic chromophores such as acriflavin (af), methyl green, and rhodamine b to b. thuringiensis. af gave the best photoprotection and a level of 0.42 mmol/g dye absorbed per gram of b. thuringiensis was highly toxic even after 12 hr of ultra ... | 1991 | 2066575 |
| [control of fly larvae in a pig farm by oral administration of thuridan to pigs]. | the studies were carried out in an experimental pig farm on 402 animals with thuridan (spore of delta-endotoxin complex of bacillus thuringiensis kurstaki). it was applied orally, as feed additive in a concentration of 0.1 and 0.5% for three current days. the efficacy of thuridan was established with the use of fly-catchers which were hung in the same places--once before and three times after thuridan had been used. after 3 application of thuridan the number of flies decreased by 88%. | 1994 | 8023511 |
| peptide mapping of different bacillus thuringiensis toxin gene products by cnbr cleavage in sds-page gels. | a cyanogen bromide fragmentation reaction of 3 hr in sodium dodecyl sulfate gel slices was used for the degradation of the toxins coded by the three cryia genes from bacillus thuringiensis kurstaki. peptide patterns diagnostic for each toxin gene product were observed. treatment longer than 3 hr led to the weakening and disappearance of protein bands. in 9 out of 16 wild b. thuringiensis strains tested, it was determined that only one of the cryia genes was being expressed; in 6 strains, one to ... | 1991 | 2002246 |
| insecticidal activity of the cryiia protein from the nrd-12 isolate of bacillus thuringiensis subsp. kurstaki expressed in escherichia coli and bacillus thuringiensis and in a leaf-colonizing strain of bacillus cereus. | a 4.0-kb bamhi-hindiii fragment encoding the cryiia operon from the nrd-12 isolate of bacillus thuringiensis subsp. kurstaki was cloned into escherichia coli. the nucleotide sequence of the 2.2-kb acci-hindiii fragment containing the nrd-12 cryiia gene was identical to the hd-1 and hd-263 cryiia gene sequences. expression of cryiia and subsequent purification of cryiia inclusion bodies resulted in a protein with insecticidal activity against heliothis virescens, trichoplusia ni, and culex quinqu ... | 1994 | 8161182 |
| [nucleotide sequence of the toxic domain of an insecticidal protein gene from b. thuringiensis subsp. kurstaki hd-1]. | two crystal protein genes, the 5.3kb and 6.6kb class respectively, from bacillus thuringiensis subsp. kurstaki hd-1 (b. t hd-1) had been cloned previously. based on the classification system of hofte and whiteley, these two genes should belong to cry i a (b) and cry i a (c) gene type respectively. the nucleotide sequence of the toxic domain of this cry i a (c) gene from b. t kurstaki hd-1 is firstly reported here and compared with that of cry i a (c) gene from b. t hd-73 and cry i a (b) gene fro ... | 1993 | 8178516 |
| expression of full-length and truncated forms of crystal protein genes from bacillus thuringiensis subsp. kurstaki in a baculovirus and pathogenicity of the recombinant viruses. | full-length and truncated forms of the crystal protein gene cryia(b) derived from bacillus thuringiensis subsp. kurstaki hd-1 and full-length cryia(c) gene of b. thuringiensis subsp. kurstaki hd-73 were introduced into the genome of the baculovirus autographa californica nuclear polyhedrosis virus, in place of the polyhedrin gene. all gene constructs were expressed at high levels in insect cells and insects upon infection with the recombinant viruses. the protein products were shown to be biolog ... | 1993 | 8228317 |
| the toxic moiety of the bacillus thuringiensis protoxin undergoes a conformational change upon activation. | proteolytic processing of the 133-kda crystal protein (protoxin) from bacillus thuringiensis subsp. kurstaki yields a 67-kda insecticidal toxin. differential scanning calorimetry was used to investigate whether the toxic moiety in the protoxin molecule has the same conformation as activated toxin. compared to protoxin, toxin gives rise to a more complex endotherm which extends over a 10 degrees c broader temperature range and contains a component occurring at a substantially higher temperature t ... | 1991 | 1898414 |
| stability of the delta-endotoxin gene from bacillus thuringiensis subsp. kurstaki in a recombinant strain of clavibacter xyli subsp. cynodontis. | deletion of chromosomally inserted gene sequences from clavibacter xyli subsp. cynodontis, a xylem-inhabiting endophyte, was studied in vitro and in planta. we found that nonreplicating plasmid pcg610, which conferred resistance to kanamycin and tetracycline and contained segments of c. xyli subsp. cynodontis genomic dna, integrated into a homologous sequence in the bacterial chromosome. in addition, pcg610 contains two copies of the gene encoding the cryia(c) insecticidal protein of bacillus th ... | 1991 | 1664710 |
| [comparative characteristics of mutants of bacillus thuringiensis subsp. kurstaki]. | a study of physiological and biochemical properties of 12 strains of bacillus thuringiensis subsp. kurstaki was performed. the strains studied included natural isolates similar to the type strain in their properties, a cry-spo+ mutant, and also mutants assigned to c-1 or c-73 crystovar according to the properties of their parasporal crystals and the ability to hydrolyze esculin, generate acid from salicin, and exert urease activity. the crystals produced by c-1 crystovar cultures were three time ... | 1995 | 8544785 |
| insect resistant cotton plants. | we have expressed truncated forms of the insect control protein genes of bacillus thuringiensis var. kurstaki hd-1(cryia(b) and hd-73 (cryia(c) in cotton plants at levels that provided effective control of agronomically important lepidopteran insect pests. total protection from insect damage of leaf tissue from these plants was observed in laboratory assays when tested with two lepidopteran insects, an insect relatively sensitive to the b.t.k. insect control protein, trichoplusia ni (cabbage loo ... | 1990 | 1366777 |
| contribution of bacillus thuringiensis spores to toxicity of purified cry proteins towards indianmeal moth larvae | the influence of bacillus thuringiensis subsp. kurstaki hd-1 spores upon the toxicity of purified cry1ab and cry1c crystal proteins toward susceptible and bt-resistant indianmeal moth (imm, plodia interpunctella) larvae was investigated. with susceptible larvae, hd-1 spores were toxic in the absence of crystal protein and highly synergistic (approximately 35- to 50-fold) with either cry1ab or cry1c protein. with bt-resistant imm larvae, hd-1 spores were synergistic with cry1ab and cry1c protein ... | 1996 | 8661690 |
| processing of delta-endotoxin from bacillus thuringiensis subsp. kurstaki hd-1 and hd-73 by gut juices of various insect larvae. | midgut juices were prepared from adoxophyes sp., smaller tea tortrix (stt); bombyx mori, silkworm (sw); spodoptera litura, common cutworm (ccw); plutella xylostella, diamondback moth (dbm); and musca domestica, housefly (hf) and immobilized onto sepharose 4b. delta-endotoxins (icps) from bacillus thuringiensis subsp. kurstaki hd-1 and hd-73 were digested by these immobilized gut juice proteases. all gut juices tested derived relatively proteolytic resistant cores from icp. the molecular sizes of ... | 1992 | 1328398 |
| bioassay for homogeneous parasporal crystal of bacillus thuringiensis using the tobacco hornworm, manduca sexta. | a method for determining the toxicity of bacillus thuringiensis subsp. kurstaki parasporal crystal to the tabocco hornworm, manduca sexta, is described. the use of both mortality and weight loss data have provided a highly sensitive and reproducible bioassay that can be used to compare relative toxicities of crystals from other subspecies as well as toxic components contained therein. | 1977 | 869534 |
| the hypervariable region in the genes coding for entomopathogenic crystal proteins of bacillus thuringiensis: nucleotide sequence of the kurhd1 gene of subsp. kurstaki hd1. | one of the genes for the entomophatogenic crystal protein of bacillus thuringiensis (subsp. kurstaki strain hd1) has been cloned in escherichia coli, and its nucleotide sequence determined completely. the gene is contained within a 4360-bp-long hpai-psti dna restriction fragment and codes for a polypeptide of 1,155 amino acid residues. the protoxin protein has a predicted mr of 130,625. the e. coli-derived protoxin gene product is biologically active against heliothis virescens larvae in a biote ... | 1986 | 3557124 |
| insecticidal activity of the protein encoded by the cryv gene of bacillus thuringiensis kurstaki ina-02. | a new host specificity was discovered with the insecticidal protein encoded by the cryv gene. the cryv gene was cloned from the bacillus thuringiensis kurstaki ina-02 strain, which was selected among a number of b. thuringiensis isolates because of its high activity against spodoptera litura. analyses by polymerase chain reaction (pcr) revealed that ina-02 contained the cryia(a) and cryv genes. since no spodoptera activity was observed with b. thuringiensis sotto, which contained only cryia(a), ... | 1996 | 8867460 |
| expression of chitinase-encoding genes from aeromonas hydrophila and pseudomonas maltophilia in bacillus thuringiensis subsp. israelensis. | fifty isolates of chitinase (cts)-producing bacteria were collected from soil samples and tested for their ability to degrade chitin using colloidal chitin agar as the primary plating medium. the results indicated that three isolates could degrade chitin at high ph. further studies also demonstrated that crude cts preparations from bacillus circulans (bc) no. 4.1 could enhance the toxicity of bacillus thuringiensis subsp. kurstaki (bt-k) toward diamondback moth larvae. thus, it might be useful t ... | 1996 | 8955637 |
| thin layer chromatography overlay technique in the analysis of the binding of the solubilized protoxin of bacillus thuringiensis var. kurstaki to an insect glycosphingolipid of known structure. | the hypothesis tested was that a particular glycoconjugate(s) in the exposed cell-surface membrane of susceptible insect cells acts as a receptor and/or modulator for the specific interaction with the protoxin/activated toxin of the delta-endotoxin of bacillus thuringiensis var. kurstaki. as candidates, the total neutral and acidic fraction glycolipids, and the isolated neutral glycosphingolipid components, were screened for binding activity by the thin layer chromatogram overlay technique. the ... | 1986 | 3506816 |
| palatability of leaf material contaminated with bacillus thuringiensis var. kurstaki, to hydatophylax argus, a detritivorous aquatic insect. | | 1996 | 9026162 |
| biological control studies of soft and hard ticks in egypt. i. the effect of bacillus thuringiensis varieties on soft and hard ticks (ixodidae). | the potential activity of three varieties of bacillus thuringiensis (kurstaki, israeliensis, and thuringiensis) against the soft tick argas persicus and the hard tick hyalomma dromedarii was investigated. soft ticks succumbed within a period ranging from 36 h to 5 days and hard ticks died at between 48 h and 10 days posttreatment, depending on the dose. concentrations lethal to 50% of tick populations (lc50 values) indicated that dipel 2x (b. thuringiensis var. kurstaki) was the most potent, fol ... | 1997 | 9089714 |
| amino acid sequence and entomocidal activity of the p2 crystal protein. an insect toxin from bacillus thuringiensis var. kurstaki. | the gene encoding the 66-kda entomocidal protein (p2 protein or mosquito factor) from bacillus thuringiensis var. kurstaki has been isolated by the use of a 62-mer oligonucleotide probe that encoded 21 amino acids of the p2 protein nh2 terminus. the dna sequence of the gene, designated crybi, was unique from the published sequences of other b. thuringiensis genes. however, the amino acid sequence of the p2 protein, as deduced from the dna sequence of the crybi gene, was found to contain a sequen ... | 1988 | 3121615 |
| is50l as a non-self transposable vector used to integrate the bacillus thuringiensis delta-endotoxin gene into the chromosome of root-colonizing pseudomonads. | insertion sequence is50l of transposon tn5 was used as a non-self transposable vector to integrate the delta-endotoxin gene (tox) from bacillus thuringiensis subsp. kurstaki hd-1 into the chromosome of two corn-root colonizing strains of pseudomonas fluorescens (112-12 and ps3732-3-7). a dna fragment containing the kmr gene from tn5 and tox was inserted into an is50l element (is50l-tox) contained on a suicide plasmid. transposition of is50l-tox into the chromosome of p. fluorescens 112-12 and ps ... | 1987 | 3036648 |
| characterization of monoclonal antibodies to a crystal protein of bacillus thuringiensis subsp. kurstaki. | ten monoclonal antibodies were produced against a k-1-type crystal protein of bacillus thuringiensis subsp. kurstaki. eight of the antibodies belong to the immunoglobulin g1 (igg1) subclass, with pi values ranging from 5.5 to 8.6, one could be assigned to the igg2b subclass, and one could be assigned to the igm class. competitive antibody-binding assays and analysis of antibody specificity indicated that the 10 antibodies recognized at least nine distinct antigenic determinants. eight antibodies ... | 1986 | 3759236 |
| delineation of a toxin-encoding segment of a bacillus thuringiensis crystal protein gene. | crystals of bacillus thuringiensis subsp. kurstaki hd-1-dipel contain a mr 134,000 protoxin which can be cleaved by proteolysis to a peptide of mr approximately 70,000; this peptide is lethal to lepidopteran larvae. we have analyzed the peptides produced by recombinant escherichia coli strains bearing deletions and fusions of the protoxin gene in order to delineate the portion of the gene which encodes the toxic peptide. the recombinant strains produced the toxic peptide as well as larger peptid ... | 1985 | 3888979 |
| protease activation of the entomocidal protoxin of bacillus thuringiensis subsp. kurstaki. | two isolates of bacillus thuringiensis subsp. kurstaki were examined which produced different levels of intracellular proteases. although the crystals from both strains had comparable toxicity, one of the strains, lb1, had a strong polypeptide band at 68,000 molecular weight in the protein from the crystal; in the other, hd251, no such band was evident. when the intracellular proteases in both strains were measured, strain hd251 produced less than 10% of the proteolytic activity found in lb1. th ... | 1985 | 3909962 |
| inverted repeat sequences flank a bacillus thuringiensis crystal protein gene. | two sets of inverted repeat dna sequences, ir2150 and ir1750, were discovered flanking the crystal protein gene on the 75-kilobase plasmid of bacillus thuringiensis subsp. kurstaki hd73. a restriction map of ca. 40 kilobases around the crystal protein gene was constructed, and the positions of the copies of ir2150 and ir1750 were determined. three copies of ir2150 were found flanking the crystal protein gene in an inverted orientation, and one partial and three intact copies of ir1750 were found ... | 1984 | 6090438 |
| transcriptional and translational start sites for the bacillus thuringiensis crystal protein gene. | the nucleotide sequence of the promoter region and part of the coding region of the crystal protein gene from bacillus thuringiensis var. kurstaki hd-1-dipel has been determined by analysis of a recombinant plasmid from escherichia coli. the start points for transcription of the gene in b. thuringiensis and in the e. coli strain carrying the recombinant plasmid were located by s1 nuclease mapping. two adjacent start sites were identified using rnas synthesized during sporulation of b. thuringien ... | 1983 | 6296116 |
| cloning and expression of full-length delta-endotoxin cryia(c) gene in three kinds of prokaryotic systems using shuttle vector pht3101. | two fragments, 6.5kb and 4.3kb encoding 5' end and 3' end of delta-endotoxin cryia(c) gene, respectively, were selected from the bacillus thuringiensis kurstaki-hd-73 75kb plasmid gene pool using random primer labelling delta-endotoxin cryia(b) gene probe. the full-length 3.92kb cryia(c) gene including 5' end 152 bp promoter sequence and 3' end 198 bp terminater sequence was rebuilt after uncoding sequences were deleted. three kinds of engineering strains harbouring the same recombinant plasmid ... | 1996 | 9639817 |
| processing of delta-endotoxin of bacillus thuringiensis subsp. kurstaki hd-1 in heliothis armigera midgut juice and the effects of protease inhibitors. | bombyx mori was found to be more sensitive to the protoxins of hd-1 than heliothis armigera. sds-page analysis showed that a large amount of activated toxin was yielded from protoxin by b. mori gut juice while little was yielded by h. armigera. further degradation of activated toxin was observed in h. armigera midgut juice detected by sds-page. ph influenced the proteolytic activity of the midgut juice significantly, but there was no obvious effect of ph on the degradation of activated toxin. sp ... | 1998 | 9647704 |
| analysis of 66 kda toxin from bacillus thuringiensis subsp. kurstaki reveals differential amino terminal processing of protoxin by endogenous protease(s). | the endogenous protease(s) activated crystal toxin from bacillus thuringiensis subsp. kurstaki was purified and examined. the purified toxin was homogenous, as demonstrated by two-dimensional polyacrylamide gel electrophoresis and contained 1.38 mumoles neutral sugar and 9 nmoles sialic acid per mg protein amino terminal amino acid sequence data revealed that the toxin is a cleavage product of 132 kda protoxin with glutamic acid-30 of the deduced amino acid sequence of the crystal protein (schne ... | 1998 | 9713700 |
| [screening and rapid identification of bacillus thuringiensis mutants]. | mutants of bacillus thuringiensis subsp. kurstaki ntu 9 and bt 158, which were isolated previously for using the diamondback moth as a target insect in taiwan, were screening by either protein electrophoresis of intracellular proteins or enzyme-linked immunosorbent assay (elisa). the optimal conditions of effective protein electrophoresis were (1) 24-hour cells harvested from nutrient broth were crashed by petite glass beads followed by centrifugation. and (2) the supernatant pretreated by heati ... | 1994 | 9747349 |
| two types of entomocidal toxins in the parasporal crystals of bacillus thuringiensis kurstaki. | two types of entomocidal proteins of bacillus thuringiensis kurstaki were isolated from the parasporal bodies (crystals), and their structures were compared with each other in relation to the toxic activity. when the crystals were dissociated in 2% 2-mercaptoethanol at ph 10, a protein of mr = 135,000, called delta-endotoxin, was liberated. the crystals of a strain of b. thuringiensis kurstaki, the hd-1 strain, also released another protein in small quantities. this minor component of hd-1, whic ... | 1983 | 6357098 |
| replication mechanism and sequence analysis of the replicon of paw63, a conjugative plasmid from bacillus thuringiensis. | a 5.8-kb fragment of the large conjugative plasmid paw63 from bacillus thuringiensis subsp. kurstaki hd73 containing all the information for autonomous replication was cloned and sequenced. by deletion analysis, the paw63 replicon was reduced to a 4.1-kb fragment harboring four open reading frames (orfs). rep63a (513 amino acids [aa]), encoded by the largest orf, displayed strong similarity (40% identity) to the replication proteins from plasmids pambeta1, pip501, and psm19035, indicating that t ... | 1999 | 10322022 |
| an improved enzyme-linked immunoassay for the detection and quantification of the entomocidal parasporal crystal proteins of bacillus thuringiensis subsp. kurstaki and israelensis. | an improved and simplified enzyme-linked immunosorbent assay (elisa) was developed for the detection and quantification of parasporal crystalline toxins from bacillus thuringiensis subsp. kurstaki. the improved procedure involved pretreatment of the polystyrene cuvettes with glutaraldehyde before antibody coating. a direct comparison of treated and untreated cuvettes is provided. elisas were then used for the analysis of the entomocidal crystalline proteins in commercial and experimental formula ... | 1984 | 6442289 |
| regulation of protoxin synthesis in bacillus thuringiensis. | a derivative of bacillus thuringiensis subsp. kurstaki (hd-1) formed parasporal inclusions at 25 degrees c, but not at 32 degrees c. this strain differed from the parent only in the loss of a 110-megadalton (md) plasmid, but plasmid and chromosomal copies of protoxin genes were present in both strains. on the basis of temperature shift experiments, the sensitive period appeared to be during midexponential growth, long before the time of protoxin synthesis at 3 to 4 h after the end of exponential ... | 1984 | 6725205 |
| cloning and expression of the bacillus thuringiensis crystal protein gene in escherichia coli. | sau 3a1 partial digestion fragments from bacillus thuringiensis var. kurstaki hd-1 plasmid dna were ligated into the bamhi site of the cloning vector pbr322 and transformed into escherichia coli strain hb101. colonies presumed to contain recombinant plasmids were screened for production of an antigen that would react with antibody made against b. thuringiensis crystals. one strain, es12, was isolated by using this procedure. es12 contains a plasmid of mr 11 x 10(6) that has dna sequence homology ... | 1981 | 7019914 |
| 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 |
| bacillus thuringiensis cryia(a) insecticidal toxin: crystal structure and channel formation. | the activated 65 kda lepidopteran-specific cryia(a) toxin from the commercially most important strain bacillus thuringiensis var. kurstaki hd-1 has been investigated by x-ray diffraction and for its ability to form channels in planar lipid bilayers. its three-dimensional structure has been determined by a multiple isomorphous replacement method and refined at 2.25 a resolution to an r-factor of 0.168 for data with i > 2 delta (i). the toxin is made of three distinct domains. the n-terminal domai ... | 1995 | 7490762 |
| increased efficacy of bacillus thuringiensis subsp. kurstaki in combination with tannic acid. | we identified tannic acid as an inexpensive additive that increased the efficacy of sublethal concentrations of bacillus thuringiensis subsp. kurstaki (berliner). tannic acid mimicked the active constituents contained in an aqueous, tannin-rich extract of taxus baccata (l.) bark that retarded development of heliothis virescens (f.) larvae at 10,000 ppm; most larvae remained in first and second stage when treated with 250-10,000 ppm of tannic acid. instar development of trichoplusia ni (hübner) l ... | 1995 | 7722082 |
| distribution of cryv-type insecticidal protein genes in bacillus thuringiensis and cloning of cryv-type genes from bacillus thuringiensis subsp. kurstaki and bacillus thuringiensis subsp. entomocidus. | dna dot blot hybridizations with a cryv-specific probe and a cryi-specific probe were performed to screen 24 bacillus thuringiensis strains for their cryv-type (lepidopteran- and coleopteran-specific) and cryi-type (lepidopteran-specific) insecticidal crystal protein gene contents, respectively. the cryv-specific probe hybridized to 12 of the b. thuringiensis strains examined. most of the cryv-positive strains also hybridized to the cryi-specific probe, indicating that the cryv genes are closely ... | 1995 | 7793960 |
| cytolytic differences among lepidopteran cell lines exposed to toxins of bacillus thuringiensis subsp. kurstaki (hd-263) and aizawai (hd-112): effect of aminosugars and n-glycosylation. | comparison of lytic-dose response behavior of seven lepidopteran cell lines to the activated delta-endotoxin polypeptides of bacillus thuringiensis subspecies kurstaki (hd-263) and aizawai (hd-112) indicated distinct differences among the lines. the lines derived from spodoptera species s. exigua (urc-se-1a) and s. littoralis (uiv-sl-575) were more susceptible to lysis by aizawai toxin (bta) than kurstaki toxin (btk) as were cells from the lymantria dispar line (iplb-ld652y). however, the concen ... | 1994 | 7842169 |
| [laboratory studies of the usefulness of biopreparation dipel in reducing the german cockroach (blattella germanica l.) population]. | in the studies conducted for finding of biological factors effectively controlling insects of hygienic importance german cockroaches were subjected to the action of an insecticide containing spores of bacillus thuringiensis var. kurstaki. one gram of the insecticide contained 25 miliard (us billion) spores with protein endotoxin crystals. the insects were given drinking water and food containing 1.0%, 0.5%, 0.25%, 0.125% of the initial preparation. the experiment was carried out on 1800 cockroac ... | 1993 | 8016546 |
| a carbon-limited medium for growth and sporulation of bacillus thuringiensis var. kurstaki. | a culture medium for batch production of d-endotoxin by bacillus thuringiensis (b., t.) has been modified. through batch and continuous cultivation studies, the original medium was diagnosed to be limited in organic nitrogen. corn steep liquor was found to be an excellent source for the organic nitrogen and its addition resulted in a carbon limited medium and in a significant increase in the amount of spore-toxin complex formed in shake flasks. results of bioassay, conducted on trichoplusia ni, ... | 1995 | 8972135 |
| kurstakins: a new class of lipopeptides isolated from bacillus thuringiensis. | a novel class of lipopeptides was isolated from bacillus thuringiensis kurstaki hd-1. four compounds (1-4) were separated by high-performance liquid chromatography and their primary structures determined using a combination of chemical reactions and mass spectrometry. the four lipopeptides were found to have the same amino acid sequence, thr-gly-ala-ser-his-gln-gln, but different fatty acids. the fatty acyl chain is linked to the n-terminal amino acid residue via an amide bond. each lipopeptide ... | 2000 | 11087590 |
| unique regulation of crystal protein production in bacillus thuringiensis subsp. yunnanensis is mediated by the cry protein-encoding 103-megadalton plasmid. | in sporulating cultures of bacillus thuringiensis subsp. yunnanensis hd977, two cell types are observed: cells forming only spores and cells forming only crystals. curing analysis suggested that the crystal proteins are plasmid encoded. through plasmid transfer experiments, it was established that a 103-mda plasmid is involved in the crystal production. conjugal transfer of this plasmid to cry- recipient cells of bacillus thuringiensis subsp. kurstaki hd73-26 conferred the ability to produce cry ... | 1997 | 9212426 |
| biochemical and molecular characterization of the insecticidal fragment of cryv. | two c-terminal deletion constructs were made to study the effect of such deletions on the biological activity of the cryv protein of bacillus thuringiensis subsp. kurstaki. the results of feeding on neonatal larvae of ostrinia nubilalis (european corn borer [ecb]) indicated that the 50% lethal dose of the full-length cryv protein was 3.34 micrograms/g of diet (95% fiducial limits, 2.53 to 4.32 micrograms/g of diet). removal of 71 amino acids (aa) from the c terminus had little effect on toxicity ... | 1997 | 9212427 |
| cell integrity markers for in vitro evaluation of cytotoxic responses to bacteria-containing commercial insecticides. | toxicity of two commercial "bt" products, containing bacillus thuringiensis subsp. kurstaki spores (btk) and associated parasporal inclusion body proteins, was tested in vitro using two unrelated lepidoperan cell lines and several markers of cell integrity (morphology, quantification of loss of adherence and electron transport (redox) activity, and degradation of nuclear dna, actin, hsp-70, and beta-tubulin). with doses of 10(-7), 10(-5), and 10(-3) international units (iu)/target cell, these ma ... | 1997 | 9262955 |
| involvement of an endogenous metalloprotease in the activation of protoxin in bacillus thuringiensis subsp. kurstaki. | insecticidal crystal proteins harvested from sporulated cultures of bacillus thuringiensis subsp. kurstaki contain the protoxin (mr 132 kda) and minor amounts of toxin (66 kda). the proteolytic processing of 132 kda protoxin to an active 66 kda toxin is brought about by exogenous proteases or larval gut enzymes. under denaturing/reducing conditions this conversion is also mediated by endogenous protease(s) of the producer organism. this endogenous protease is identified as a metalloprotease as t ... | 1997 | 9285057 |
| a uv tolerant mutant of bacillus thuringiensis subsp. kurstaki producing melanin. | a uv-resistant mutant (bt-m) of bacillus thuringiensis subsp. kurstaki, producing a dark brown pigment, identified as melanin, was studied. bt-m had higher larvicidity against heliothis armigera than its parent. survival of bt-m spores and their insecticidal activity to irradiation at 254 nm and 366 nm were higher than those of the parent. the only toxic polypeptide produced by bt-m was cry1ac (130 kda); it lost cry1aa, cry2aa, and cry2ab. | 2002 | 11727037 |
| endogenous protease-activated 66-kda toxin from bacillus thuringiensis subsp. kurstaki active against spodoptera littoralis. | the anti-lepidopteran toxin from sporulated bacillus thuringiensis subsp. kurstaki cells, generated by the proteolytic action of endogenous protease(s) on the protoxin, was purified and studied to identify the effect of such proteolysis on the biochemical nature of the toxin. the active toxin was purified employing anion-exchange chromatography to absolute homogeneity, as indicated by sds-page and western blotting. antisera to the purified toxin (66 kda) crossreacted with the protoxin (132 kda) ... | 1998 | 9485601 |