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cloning of a fragment of the gene cryivb from bacillus thuringiensis var. israelensis coding for the aminoterminal segment of a 130 kda larvicidal endotoxin. 19958524078
bacillus thuringiensis subsp. oswaldocruzi and bacillus thuringiensis subsp. brasiliensis, two novel brazilian strains which determine new serotype h38 and h39, respectively. 19958524081
mechanism of action of bacillus thuringiensis toxins.the selectivity of bacillus thuringiensis toxins is determined both by the toxin structure and by factors inherent to the insect. these toxins contain distinct domains that appear to be functionally important in toxin binding to protein receptors in the midgut of susceptible insects, and the subsequent formation of a pore in the insect midgut epithelium. in this article features necessary for the insecticidal activity of these toxins are discussed. these include toxin structure, toxin processing ...19958524088
exploration of receptor binding of bacillus thuringiensis toxins.wild type and mutant toxins of bacillus thuringiensis delta-endotoxins were examined for their binding to midgut brush border membrane vesicles (bbmv). cryiaa, cryiab, and cryiac were examined for their binding to gypsy moth (lymantria dispar) bbmv. the binding of cryiaa and cryiac was directly correlated with their toxicity, while cryiab was observed to have lower binding than expected from its toxicity. the latter observation confirms the observation of wolfersberger (1990). the "rule" of reci ...19958524089
transfer of toxin genes to alternate bacterial hosts for mosquito control.mosquitoes are vector of serious human and animal diseases, such as malaria, dengue, yellow fever, among others. the use of biological control agents has provide an environmentally safe and highly specific alternative to the use of chemical insecticides in the control of vector borne diseases. bacillus thuringiensis and b. sphaericus produce toxic proteins to mosquito larvae. great progress has been made on the biochemical and molecular characterization of such proteins and the genes encoding th ...19958524091
specific pcr primers directed to identify cryi and cryiii genes within a bacillus thuringiensis strain collection.in this paper we describe a pcr strategy that can be used to rapidly identify bacillus thuringiensis strains that harbor any of the known cryi or cryiii genes. four general pcr primers which amplify dna fragments from the known cryi or cryiii genes were selected from conserved regions. once a strain was identified as an organism that contains a particular type of cry gene, it could be easily characterized by performing additional pcr with specific cryi and cryiii primers selected from variable r ...19958526493
resistance to bacillus thuringiensis cryia delta-endotoxins in a laboratory-selected heliothis virescens strain is related to receptor alteration.the bacillus thuringiensis toxin-binding properties of midgut epithelial cells from two strains of heliothis virescens were compared. one h. virescens strains (yhd2) which was selected against cryiac toxin had over 10,000-fold resistance to cryiac toxin relative to the susceptible strain and was cross-resistant to cryiaa and cryiab. the second h. virescens strain (ydk) was susceptible to these toxins in the order cryiac > cryiab > cryiaa. receptor-binding properties of cryiaa, cryiab, and cryiac ...19958526494
the protoxin composition of bacillus thuringiensis insecticidal inclusions affects solubility and toxicity.most bacillus thuringiensis strains producing toxins active on lepidoptera contain several plasmid-encoded delta-endotoxin genes and package related protoxins into a single inclusion. it was previously found that in b. thuringiensis subsp. aizawai hd133, which produces an inclusion comprising the cryiab, cryic, and cryid protoxins, there is a spontaneous loss in about 1% of the cells of a 45-mda plasmid containing the cryiab gene. as a result, inclusions produced by the cured strain were less re ...19958526519
cloning and expression of a novel toxin gene from bacillus thuringiensis subsp. jegathesan encoding a highly mosquitocidal protein.a gene, designated cry11b, encoding a 81,293-da crystal protein of bacillus thuringiensis subsp. jegathesan was cloned by using a gene-specific oligonucleotide probe. the sequence of the cry11b protein, as deduced from the sequence of the cry11b gene, contains large regions of similarity with the cry11a toxin (previously cryivd) from b. thuringiensis subsp. israelensis. the cry11b protein was immunologically related to both cry11a and cry4a proteins. the cry11b gene was expressed in a nontoxic s ...19958534090
increased susceptibility to bacillus thuringiensis associated with pyrethroid resistance in bovicola (damalinia) ovis (phthiraptera mallophaga: possible role of monooxygenases.a comparison of the toxicity of bacillus thuringiensis (berliner) to pyrethroid-susceptible and -resistant strains of bovicola (damalinia) ovis showed that b. thuringiensis and pyrethroid toxicity were inversely related. the b. ovis strain with an apparent monooxygenase-mediated pyrethroid resistance mechanism was significantly more susceptible to b. thuringiensis. susceptibility to b. thuringiensis in both the pyrethroid-susceptible and -resistant strains was significantly reduced after adminis ...19958537542
control of mosquito larvae by encapsulated pathogen bacillus thuringiensis var. israelensis.bacillus thuringiensis var. israelensis (b.t.i.) containing alginate microcapsules were prepared in order to maintain durable formulations which could resist several effects causing reduced efficiency during applications. b.t.i. spores were harvested through nysm agar plates and encapsulated in ca-alginate (0.5-2.0% w/v) gels without any significant loss of sporal or larvicidal activity. the effect of acidic ph on the larvicidal toxin was tested using culex sp. larvae in the laboratory. the algi ...19958544095
[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 ...19958544785
the potential for malaria control with the biological larvicide bacillus thuringiensis israelensis (bti) in peru and ecuador.a study on the efficacy of bti spraying in mosquito breeding places was undertaken in the pacific coast of peru and ecuador and in the amazon area of peru. it was shown that bti is a powerful larvicide for anopheles larvae, although it sinks quickly, whereas anopheles larvae feed at the water surface. the duration of its effect was less than 7 days with the exception of the amazon area of peru, where it was approximately 10 days. in two study areas, bti was sprayed weekly over periods of 10 and ...19958546038
the structure of bacterial cell cycle and age structure of bacterial populations.study of synchronous and asynchronous cultures of bacillus megaterium, bacillus thuringiensis and bacillus licheniformis has shown that the duration of chromosomal dna replication (period c) is proportional to the generation time, and time between two cycles of the dna replication (known as period i). the duration of period c is nearly constant and makes up from 0.5 to 1.0 hour at the variations of the generation time from 1.5 to 2.75 hours. the duration of period b (the time between the termina ...19958548068
establishment and characterization of three cell lines from aedes triseriatus (diptera: culicidae).three cell lines (a.t. grip-1, 2, and 3) were established from aedes triseriatus (say) embryonated eggs or neonate larvae and their morphology, growth, karyotype, and isozyme pattern were studied. the isozyme alleles observed in the 3 cell lines also were found in adults of the original mosquito colony. each cell line differed in enzymatic, morphological, and karyotypical patterns. la crosse encephalitis (lac) and snowshoe hare (ssh) viruses, members of the california encephalitis virus group, w ...19958551501
[laboratory examination of the effectiveness of new biological preparations for reducing populations of cockroaches (blattella germanica l.)].the usefulness of new commercial products of biological origin (biobit, novo skeetal and novodor) was tested in cockroaches (blattella germanica l.) control. biobit proved to be the most effective in reduction of cockroaches population. its higher activity against cockroaches was observed in all concentrations tested. females were more sensitive for all tested products than males.19958552970
effect of two commercial formulations of bacillus thuringiensis subsp. kurstaki (dipel 8l and dipel 8af) on the collembolan species folsomia candida in a soil microcosm study. 19958563213
comparative larvicidal activities of the four bacillus thuringiensis serovars against a chironomid midge, paratanytarsus grimmii (diptera: chironomidae).the four reference strains of bacillus thuringiensis, known to be pathogenic for mosquito larvae of the family culicidae (diptera), were examined for their larvicidal activities against a chironomid species, paratanytarsus grimmii (diptera: chironomidae). of the four, the type strain of b. thuringiensis serovar israelensis (h14) exhibited the highest activity against both early- and late-instar larvae, while the type strain of serovar kyushuensis (h11ac) and the strain 73-e-10-2 (h10, serovar da ...19958564369
characterization of baculovirus insecticides expressing tailored bacillus thuringiensis cryia(b) crystal proteins.full-length, truncated, and mature forms of the cryia(b) insecticidal crystal protein gene of bacillus thuringiensis were engineered into the p10 locus of autographa californica nuclear polyhdrosis virus (acnpv). a signal sequence of heliothis virescens juvenile hormone esterase was introduced at the n-terminus of these constructs to induce secretion. all recombinants, except those containing the mature toxin, produced high levels of cryia(b) icps in insect cells. thirty percent of the intracell ...19958568280
a protein complex from choristoneura fumiferana gut-juice involved in the precipitation of delta-endotoxin from bacillus thuringiensis subsp. sotto.a 75 kda protein from spruce budworm (choristoneura fumiferana) gut-juice has been isolated and shown to cause a specific precipitation of the delta-endotoxin from bacillus thuringiensis subsp. sotto. this 75 kda protein, separated by either column chromatography or sds-page, caused precipitation of the sotto toxin in both agarose diffusion gels and the page gels. the precipitation event leads to limited proteolysis of the toxin and loss of larval toxicity. sds-page analysis of the precipitated ...19958580910
brush border membrane aminopeptidase-n in the midgut of the gypsy moth serves as the receptor for the cryia(c) delta-endotoxin of bacillus thuringiensis.aminopeptidase-n (ap-n) was purified from gypsy moth (lymantria dispar, l.) brush border membrane vesicles (bbmv) proteins by mono-q chromatography and superdex-75 gel filtration in the presence of the zwitterionic detergent, chaps, using fplc. the purified ap-n, identified by its enzymatic activity, had an apparent size of 100 kda, and was identified as the unique bacillus thuringiensis insecticidal toxin, cryia(c), binding protein. ap-n clearly displayed strong binding to cryia(c), exhibiting ...19958580914
phage typing of bacillus subtilis and b. thuringiensis.phage typing schemes for bacillus subtilis and b. thuringiensis were constructed using 98 phages and 743 bacterial strains. most phages were host-species-specific. phages were classified by electron microscopy. the b. subtilis scheme includes 10 phages and 29 phage types. the b. thuringiensis scheme comprises 8 phages and 25 phage types and can be applied to b. cereus. there is no correlation between h antigen serotypes and phagovars in b. thuringiensis. characteristics of typing phages are desc ...19958584788
cloning of a novel crystal protein gene cry1k from bacillus thuringiensis subsp. morrisoni.a novel crystal protein gene cry1k has been cloned and sequenced from a bacillus thuringiensis subsp. morrisoni bf190 isolated from phylloplane. the upstream promoter region of cry1k was almost identical with that of cry1b. the deduced amino acid sequence of cry1k contains 1215 amino acid residues with an estimated molecular mass of 137 kda. comparison of the amino acid sequence of the cry1k with that of cry proteins revealed that cry1k is most closely related to cry1b and cry1i. cry1k has a hig ...19958586263
a 28,000 mol. wt toxin from bacillus thuringiensis israelensis induces cation transport in rat muscle cultures.the mechanism by which the bacillus thuringiensis israelensis (bti) 28,000 mol. wt toxin exerts its effect on mature muscle cultures was examined. the toxin inhibited na+/k(+)-atpase activity as revealed by 86rb influx. a 50% inhibition of na+/k(+)-atpase activity was obtained with 0.2 microgram/ml of the toxin. the inhibition was time and dose dependent, and it was reversible with low doses of the toxin (up to 0.2 microgram/ml. a considerable release of 86rb was obtained by doses greater than 0 ...19958588218
crystallization of a membrane pore-forming protein with mosquitocidal activity from bacillus thuringiensis subspecies kyushuensis.cytb, a membrane pore-forming toxin from bacillus thuringiensis subspecies kyushuensis, is specifically toxic to dipteran insect larvae but broadly cytolytic in vitro. it has been purified in the protoxin form from a recombinant escherichia coli source and crystals have been obtained which diffract x-rays to at least 2.6 a resolution. the tendency for cytb to aggregate in solution was overcome by including 50 mm of urea or 8 mm of ethanolamine during crystallization. mutants designed to add or s ...19958592711
regulation of insecticidal crystal protein production in bacillus thuringiensis.the production of insecticidal crystal proteins (icps) in bacillus thuringiensis normally coincides with sporulation, resulting in the appearance of parasporal crystalline inclusions within the mother cell. in most instances, the temporal and spatial regulation of icp gene expression is determined at the transcriptional level by mother-cell-specific sigma factors that share homology with sigma e and sigma k from bacillus subtilis. the cryiii icp genes are a notable exception; these genes are tra ...19958596449
resistance and the control of sheep ectoparasites.for about 100 years australian woolgrowers have used a variety of chemicals to control blowflies, lice and other ectoparasites of sheep. while the chemicals have changed considerably the application technology has not changed very much at all. chemicals registered for use on sheep have paralleled the evolution of synthetic insecticides with the unfortunate consequence of the development of resistance in the australian sheep blowfly, lucilia cuprina, following closely behind. organochlorine (diel ...19958635885
diarrhoeal enterotoxin production by strains of bacillus thuringiensis isolated from commercial bacillus thuringiensis-based insecticides.strains of bacillus cereus and b. thuringiensis were tested by the tecra via kit for the ability to produce a diarrhoeal enterotoxin. the strains of b. thuringiensis were isolated from commercial b. thuringiensis-based insecticides (bactimos, dipel, florbac, fc, foray 48b, novodor fc, turex, vectobac, xentari). the production of diarrhoeal enterotoxin varied by a factor of more than 100 among the different strains tested. b. cereus (f4433/73) produced the highest amount of enterotoxin and the b. ...19958745010
[interspecific protoplast fusion between bacillus thuringensis bt-3701 and bacillus megaterium bm-107].the results of the interspecific protoplast fusion between b. thuringensis sub. kurstaki bt-3701 which has pesticide ability, and b. megaterium var. phosphaticum bm-107 which has decomposing phosphate activity, were reported. high frequency of protoplast formation and regeneration was obtained with 4h activated bm-107 treated by 100 micrograms/ml lysozyme, and with 2h activated bt-3701 treated by 3% glycin and mild temperature. using 40% peg and 5% nascent ca2+ to treat the parential protoplast ...19958701582
field trials with methoprene, temephos, and bacillus thuringiensis serovar israelensis for the control of larval culiseta melanura.in 1992, altosid (methoprene) pellets, abate (temephos) 5 cg, and bactimos (bacillus thuringiensis serovar israelensis) granules were applied aerially to small field plots within a culiseta breeding swamp. aspects measured included the deposition and diffusion of larvicides into larval crypts and effects on larval culiseta melanura and nontarget aquatic organisms. formulations were deposited at approximately 50% of application rates. the presence of methoprene in 8 crypt water samples indicated ...19958825501
a new serovar of bacillus thuringiensis possessing 28a28c flagellar antigenic structure: bacillus thuringiensis serovar jegathesan, selectively toxic against mosquito larvae.a novel bacillus thuringiensis strain highly toxic to mosquitoes was isolated from soil samples in malaysia. this strain was shown to display a new subfraction of the h-28 flagellar antigen determining a new serovar h28a28c, which was designated serovar jegathesan. bioassays indicated that culex quinquefasciatus larvae are the most susceptible to this new isolate, whereas toxicity to anopheles maculatus and aedes aegypti larvae was 10 times lower. the potency of this new serotype is also compara ...19958825511
evaluation of entomopathogenic bacteria against aedes polynesiensis, the vector of lymphatic filariasis in french polynesia.thirteen strains among 3 species of entomopathogenic bacteria were tested against 3 medically important mosquito species in french polynesia. two strains of bacillus thuringiensis were highly toxic to aedes polynesiensis, aedes aegypti, and culex quinquefasciatus. six of 7 strains of bacillus sphaericus tested were highly toxic to cx. quinquefasciatus but not to the aedes spp. clostridium bifermentans serovar. malaysia was more toxic to ae. polynesiensis than to the other 2 species. entomopathog ...19958825516
efficacy of ground ultra-low volume larvicidal treatments using temephos and bacillus thuringiensis var. israelensis against culex pipiens larvae.spray drift determinations of truck-mounted ulv applications of temephos and bacillus thuringiensis var. israelensis (b.t.i.) in simulated field trials were conducted in the baix llobregat area near barcelona, spain, using larval culex pipiens as bioindicators. a 50:50 temephos:oil mixture applied at 350 ml/min, while traveling 9 kph, resulted in 100% control of larvae 10-50 m from the point of application (with the exception of 82% mortality at 30 m); control decreased rapidly to 50% at 55 m. m ...19958825518
community based dengue control in columbia: people's knowledge and practice and the potential contribution of the biological larvicide bti (bacillus thuringiensis israelensis).a study on dengue control was undertaken in a poor urban area in cúcuta, colombia. the first objective was to describe people's knowledge, attitudes and practices regarding dengue fever, the transmission of the disease and possible preventive measures. the second objective was to analyse the infestation of the community with aedes aegypti larvae, and the third objective to test the efficacy of bti (bacillus thuringiensis israelensis) with respect to the level and duration of reduction of ae. aeg ...19958826104
[comparative study of 3 heterologous expression systems for obtaining recombinant bacillus thuringiensis delta-endotoxins].cryia(b) and cryia(c) genes encoding active fragments of bacillus thuringiensis delta-endotoxins were cloned downstream of the pr and pt7 promoters from the lambda and t7 bacteriophages, respectively. cryia(b) gene was also fused with the gene encoding protein a from staphylococcus aureus cloned under the control of the pr promoter. there were no remarkable differences in the expression levels of the cloned genes in e. coli, but the western blot analysis allowed distinct protein quality for the ...19958850342
ionic permeabilities induced by bacillus thuringiensis in sf9 cells.the effect of bacillus thuringiensis insecticidal toxins on the monovalent cation content and intracellular ph (phi) of individual sf9 cells of the lepidopteran species spodoptera frugiperda (fall armyworm) was monitored with the fluorescent indicators potassium-binding benzofuran isophthalate (pbfi) and 2',7'-bis(carboxyethyl)-5,6-carboxyfluorescein (bcecf). the sequential removal of k+ and na+ from the medium, in the presence of cryic, a toxin which is highly active against sf9 cells, caused s ...19958558602
semiautomated quantification of cytotoxic damage induced in cultured insect cells exposed to commercial bacillus thuringiensis biopesticides.a convenient in vitro bioassay based on semiautomated quantification of live-cell reduction of tetrazolium dyes--3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (mtt) and 2,3-bis(2-methoxy-4-nitro-5-sulphophenyl)-2h-tetrazolium-5-corb oxanilide sodium salt (xtt)--to formazan was developed and used to evaluate cytotoxic effects of two commercial insecticides (bt) derived from bacillus thuringiensis subsp. kurstaki (btk). comparison of two target insect cell lines mg1 (trichoplusia ...19958666719
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, ...19958972135
malaria control in a nutshell: palmira ventosilla.palmira ventosilla, a 35-year old peruvian microbiologist, and her team of researchers at the alexander von humboldt tropical medicine institute in lima, with funding from idrc, have developed a method of controlling malaria through biological control of mosquito larvae. bacillus thuringiensis var. israelensis h-14 (bti) is a naturally occurring bacterium that kills the larvae of anopheles; it is harmless to humans, but expensive to buy from commercial dealers. the team discovered an inexpensi ...199512288548
monomers and dimers of acetylcholinesterase in human meningioma are anchored to the membrane by glycosylphosphatidylinositol.amphiphilic monomers and dimers of acetylcholinesterase (ache) and hydrophilic tetramers of butyrylcholinesterase (buche) were released by extracting human meningioma with tris-saline and tris-saline-triton x-100 buffers. the amphiphilic or hydrophilic behavior of the ache and buche forms was assessed by sedimentation analysis, hydrophobic chromatography and triton x-114 phase-partitioning. a significant fraction of the amphiphilic ache species was converted into hydrophilic components by incuba ...19957478260
[characters and insecticidal polypeptide of a new strain of bacillus thuringiensis subsp. kenyae in china].a new strain of bacillus thurinigiensis bt with high toxicity against noctuidae larvae has been screened for many generations since isolated from larvae candle of aphomia gularis in yiyang county, jiangxi province, in china. by comparison and analysis of results of physiological and biochemical test, flagella antigen identification and esterase type, the strain is identified as h4a-4c bt serovar. kenyae. since its crystal protein type and plasmid type are different from those of bt serovar. keny ...19957483588
trehalose and sucrose protect both membranes and proteins in intact bacteria during drying.the microorganisms escherichia coli dh5 alpha and bacillus thuringiensis hd-1 show an increased tolerance to freeze-drying when dried in the presence of the disaccharides trehalose and sucrose. when the bacteria were dried with 100 mm trehalose, 70% of the e. coli and 57% of the b. thuringiensis organisms survived, compared with 56 and 44%, respectively, when they were dried with sucrose. only 8% of the e. coli and 14% of the b. thuringiensis organisms survived drying without the sugars. fourier ...19957486995
isolation and identification of novel toxins from a new mosquitocidal isolate from malaysia, bacillus thuringiensis subsp. jegathesan.a new mosquitocidal bacillus thuringiensis subsp., jegathesan, has recently been isolated from malaysia. parasporal crystal inclusions were purified from this strain and bioassayed against fourth-instar larvae of culex quinquefasciatus, aedes aegypti, aedes togoi, aedes albopictus, anopheles maculatus, and mansonia uniformis. the 50% lethal concentration of crystal inclusions for each species was 0.34, 8.08, 0.34, 17.59, 3.91, and 120 ng/ml, respectively. these values show that parasporal inclus ...19957487029
enhanced production of insecticidal proteins in bacillus thuringiensis strains carrying an additional crystal protein gene in their chromosomes.a two-step procedure was used to place a cryic crystal protein gene from bacillus thuringiensis subsp. aizawai into the chromosomes of two b. thuringiensis subsp. kurstaki strains containing multiple crystal protein genes. the b. thuringiensis aizawai cryic gene, which encodes an insecticidal protein highly specific to spodoptera exigua (beet armyworm), has not been found in any b. thuringiensis subsp. kurstaki strains. the cryic gene was cloned into an integration vector which contained a b. th ...19957487039
domain iii exchanges of bacillus thuringiensis cryia toxins affect binding to different gypsy moth midgut receptors.aminopeptidase-n, purified from gypsy moth (lymantria dispar l.) brush border membrane vesicles, exhibited specific binding to cryiac toxin but not to cryiaa toxin. cryiaa-cryiac hybrid toxins were used to localize the aminopeptidase-n binding region on cryiac. slot blot assays and ligand blot experiments demonstrated that the hybrid toxins which have the residues 451 to 623, comprising essentially domain iii, from cryiac toxin exhibited strong binding to purified aminopeptidase-n and 120 kda br ...19957488105
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 ...19957490762
monoclonal antibody developed against a hemolysin of bacillus thuringiensis.a total of five hybridoma cell lines that produced monoclonal antibodies (mab) against a hemolysin (bt-hemolysin) produced by bacillus thuringiensis were established and characterized. all of these monoclonal antibodies reacted similarly not only to bt-hemolysin but also to a hemolysin (bc-hemolysin) produced by b. cereus, suggesting that the two hemolysins are immunologically indistinguishable. the mab developed in this study was also successfully applied for rapid and simple purification of bo ...19957494502
factors regulating cryivb expression in the cyanobacterium--synechococcus pcc 7942.the expression of the larvicidal bacillus thuringiensis subsp. israelensis cryivb gene in cyanobacteria has been suggested to be an effective means of controlling mosquito populations. using a variety of cryivb constructs, in this study we have examined the effect of synechococcus pcc 7942 culture age on intracellular toxin levels and have attempted to determine the mechanisms by which cryivb gene expression is regulated. the data suggest that specific degradation of the cryivb mrna limits toxin ...19957531814
delta-endotoxins induce cation channels in spodoptera frugiperda brush border membranes in suspension and in planar lipid bilayers.membrane potential measurements using a fluorescent dye indicated that two specific toxins active against spodoptera frugiperda larvae (cryic and cryid) cause immediate permeability changes in midgut epithelial brush border membrane vesicles (bbmv). the initial response and the sustained permeability change are cationic, not very k+ selective, and occur at in vivo lethal doses (nm). the toxin response has a different ion selectivity and is more sensitive to ba2+ than the intrinsic cation permeab ...19957533728
comparative analysis of the 16s to 23s ribosomal intergenic spacer sequences of bacillus thuringiensis strains and subspecies and of closely related species.bacillus thuringiensis spacer regions between the 16s and 23s rrnas were amplified with conserved primers, designated 19-mer and 23-mer primers. a spacer region of 144 bp was determined for all of 6 b. thuringiensis strains, 7 b. thuringiensis subspecies, and 11 b. thuringiensis field isolates, as well as for the closely related species bacillus cereus and bacillus anthracis. computer analysis and alignment of nucleotide sequences identified three mutations and one deletion in the intergenic spa ...19957538281
prevalence of bacillus cereus in selected foods and detection of enterotoxin using tecra-via and bcet-rpla.enterotoxigenic bacillus cereus was detected in cooked foods (17), rice noodles (3), wet wheat noodles (2), dry wheat noodles (10), spices (8), grains (4), legumes (11) and legume products (3). one hundred ninety-four (42.3%), 70 (15.3%) and 23 (5.2%) of the 459 presumptive b. cereus colonies isolated from pemba agar were identified as b. cereus, bacillus thuringiensis and b. mycoides, respectively. b. cereus isolates were examined for growth temperature, ph profile and enterotoxin production us ...19957547144
highly insect-resistant transgenic tobacco plants containing both b.t. and cpti genes.the cowpea trypsin inhibitor (cpti) gene was synthesized according to its cdna sequence using dna synthesizer and confirmed by dna sequencing. the cpti gene and modified bacillus thuringiensis (b.t.) delta-endotoxin gene were cotransformed to tobacco explants mediated by agrobacterium tumefaciens. the integrations of b.t and cpti genes were confirmed by pcr and southern hybridization. three kinds of transgenic plants were obtained: (1) containing cpti gene, (2) containing b.t gene, (3) containin ...19957548766
ssp genes and spore osmotolerance in bacillus thuringiensis israelensis and bacillus sphaericus.it was shown previously that spores and vegetative cells of bacillus sphaericus (bf) and bacillus thuringiensis israelensis (bti) are very sensitive to osmotic variations. since spore osmotolerance has been associated with their sasp (small acid soluble spore proteins) content coded by ssp genes, hybridization assays were performed with sspe and sspa genes from b. subtilis as probes and showed that bti and bf strains could lack an sspe-like gene. the b. subtilis sspe gene was then introduced int ...19957549769
irreversible binding kinetics of bacillus thuringiensis cryia delta-endotoxins to gypsy moth brush border membrane vesicles is directly correlated to toxicity.to examine the binding of bacillus thuringiensis delta-endotoxins, cryiaa, cryiab, and cryiac, to lymantria dispar (gypsy moth) brush border membrane vesicles (bbmv), saturation kinetic analyses were conducted according to a two-step interaction scheme [formula: see text] for delta-endotoxin binding to bbmv, rather than the one-step reversible binding presented in prior reports. the order of toxicity of the delta-endotoxins, as measured by the dose required for a 50% inhibition of weight gain (i ...19957559587
mobilization of bacillus thuringiensis plasmid ptx14-3.the bacillus thuringiensis subsp. israelensis (bti) plasmid ptx14-3 has been reported to contain a gene, mob14-3, with considerable homology to genes encoding mobilization proteins from other gram-positive bacteria. we have used the aggregation-mediated conjugation system recently discovered in bti to compare the mobilization kinetics of different derivatives of plasmid ptx14-3. plasmid ptx14-3 has been found to replicate by the rolling-circle mechanism and to contain a locus suppressing the for ...19957568463
bacillus thuringiensis serovar higo (flagellar serotype 44), a new serogroup with a larvicidal activity preferential for the anopheline mosquito.eight strains of bacillus thuringiensis, isolated in japan, formed spherical parasporal inclusions and exhibited low to moderate larvicidal activities for two mosquito species, anopheles stephensi and culex pipiens molestus, but not for another dipteran, telmatoscopus albipunctatus, or two lepidopterans, bombyx mori and hyphantria cunea. the anopheline toxicity (lc50 = 6.3 micrograms ml-1) was > 10 times greater than the activity on the culex mosquito. these strains were assigned to a previously ...19957576527
[change in the bacillus thuringiensis subsp. israelensis plasmid dna spectrum during growth dynamics]. 19957580992
how does bacillus thuringiensis produce so much insecticidal crystal protein? 19957592363
identification, isolation, and cloning of a bacillus thuringiensis cryiac toxin-binding protein from the midgut of the lepidopteran insect heliothis virescens.bacillus thuringiensis toxins are insecticidal to a variety of insect species. the selectivity of the toxins produced by these bacteria is dependent on both the toxin structure and the receptor sites that are present in different insect species. one of these toxins, cryiac, is highly insecticidal to the noctuid pest heliothis virescens. using toxin overlay assay, a 120-kda glycoprotein was identified as a toxin-binding protein. this protein was partially purified, its n-terminal sequence was det ...19957592988
cellular fatty acid analysis of bacillus thuringiensis ssp. israelensis (onr-60a).the cellular fatty acid composition of bacillus thuringiensis ssp. israelensis (b.t.i.) onr-60a was determined by gas-liquid chromatography (glc). isolates of onr-60a were obtained from the bacillus genetic stock center, pasteur institute, and usda culture collections. these isolates were compared to one another and the culture collections differed in the strains that they contained. eleven separate strains of onr-60a were identified, based on fatty acid composition of the cell envelope. the cur ...19957595442
the future of microbial insecticides as vector control agents.insect vectors of human diseases are subject to diseases of their own caused by viruses, bacteria, fungi, protozoans, and nematodes. over the past 30 years, many members of these groups have been evaluated as vector control agents, particularly for mosquito control. most pathogens and nematodes occur primarily in larvae, and are only effective against this stage. the principal candidate control agents studied include iridescent and nuclear polyhedrosis viruses, the bacteria bacillus thuringiensi ...19957595459
tnpi recombinase: identification of sites within tn5401 required for tnpi binding and site-specific recombination.the bacillus thuringiensis class ii transposon tn5401 encodes a recombinase protein, tnpi, that mediates the resolution of cointegrate molecules generated as intermediates during tn5401 transposition by the tnpa transposase. this recombination event requires a specific target site, or internal resolution site, at which tnpi binds and catalyzes the exchange of dna strands. gel mobility shift assays and dnase i footprinting analyses were used to localize the tnpi binding region to the sequence ext ...19957608077
mutagenesis of specificity and toxicity regions of a bacillus thuringiensis protoxin gene.two different 30-nucleotide regions of the cryiac insecticidal protoxin gene from bacillus thuringiensis were randomly mutagenized. one region was within one of seven amphipathic helices believed to be important for the formation of ion channels. there was no loss of toxicity for three test insects by any of 27 mutants, a result similar to that obtained previously for mutations within another such helix. only mutations within a region encoding the central helix have resulted in a substantial num ...19957608080
effect of low temperature on feeding rate of aedes stimulans larvae and efficacy of bacillus thuringiensis var. israelensis (h-14).experiments were conducted to determine the effects of low temperature (0 and 4 degrees c), vs. a high temperature (22 degrees c), on the feeding rate of aedes stimulans larvae, and their susceptibility to bacillus thuringiensis var. israelensis (h-14) (b.t.i.). third-instar ae. stimulans slowed but did not halt feeding at 0 and 4 degrees c compared to 22 degrees c. susceptibility of larvae, as measured by lc50 values, to b.t.i. was highest at 22 degrees c (lc50 = 0.1 ppm), and lower at 4 degree ...19957616175
comparative toxicity of selected larvicides and insect growth regulators to a florida laboratory population of aedes albopictus.five organophosphates (ops) (chlorpyrifos, chlorpyrifos methyl, fenthion, malathion, and temephos), 3 pyrethroids (bifenthrin, cypermethrin, and permethrin), and 2 microbial pesticides (bacillus thuringiensis serovar.israelensis [b.t.i.] and bacillus sphaericus) were tested as larvicides against a florida aedes albopictus population colonized in the laboratory. in addition, 3 insect growth regulators (igrs) (diflubenzuron, methoprene, and pyriproxyfen) were evaluated. all ops, except for malathi ...19957616194
control of anopheles stephensi breeding in construction sites and abandoned overhead tanks with bacillus thuringiensis var. israelensis.bacillus thuringiensis (h-14), strain 164 (bactoculicide) when applied at 1 g/m2 surface area successfully controlled anopheles stephensi breeding in construction sites, abandoned overhead tanks, and curing waters. subsequent to application, no pupal production was observed in these habitats for 3, 18, and 21 days, respectively. based on these findings, inclusion of bactoculicide in the bioenvironmental vector control strategy is suggested and fortnightly spraying in construction sites at 1 g/m2 ...19957616196
denitration of glycerol trinitrate by resting cells and cell extracts of bacillus thuringiensis/cereus and enterobacter agglomerans.a number of microorganisms were selected from soil and sediment samples which were known to have been previously exposed to nitrate ester contaminants. the two most effective bacteria for transforming glycerol trinitrate (gtn) were identified as bacillus thuringiensis/cereus and enterobacter agglomerans. for both isolates, denitration activities were expressed constitutively and gtn was not required for induction. dialysis of cell extracts from both isolates did not affect denitration, which ind ...19957618866
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 ...19957618886
immunohistochemical detection of binding of cryia crystal proteins of bacillus thuringiensis in highly resistant strains of plutella xylostella (l.) from hawaii.we detected binding of insecticidal crystal proteins from bacillus thuringiensis in one susceptible strain and six resistant strains of diamondback moth, plutella xylostella, from hawaii. immunohistochemical tests with tissue sections from larval midguts showed specific binding of cryia(a), cryia(b), and cryia(c) to brush border membranes. cryie, which is not toxic to p. xylostella, did not bind to midgut tissues. larvae from one of the resistant strains ingested extremely high concentrations of ...19957626052
molecular cloning of an insect aminopeptidase n that serves as a receptor for bacillus thuringiensis cryia(c) toxin.the bacillus thuringiensis cryia(c) insecticidal delta-endotoxin binds to a 120-kda glycoprotein receptor in the larval midgut epithelia of the susceptible insect manduca sexta. this glycoprotein has recently been purified and identified as aminopeptidase n. we now report the cloning of aminopeptidase n from a m. sexta midgut cdna library. two overlapping clones were isolated, and their combined 3095-nucleotide sequence contains an open reading frame encoding a 990-residue pre-pro-protein. the n ...19957629076
cry ia(b) transcript formation in tobacco is inefficient.chimaeric pcamv35scry genes direct in tobacco mesophyll protoplasts mrna levels of less than one transcript per cell. we provide evidence that this low cytoplasmic cry ia(b) mrna level is not due to a rapid turnover but rather results from a marginal import flow of cry messenger into the cytoplasm. run-on assays indicate that the frequency of transcription initiation is not limiting. however, the cry precursor mrna carries at least three regions that are recognized as introns. the absence of hig ...19957632920
bacillus cereus and bacillus thuringiensis isolated in a gastroenteritis outbreak investigation.during investigation of a gastroenteritis outbreak in a chronic care institution, norwalk virus was found in stool specimens from two individuals and bacterial isolates presumptively identified as bacillus cereus were isolated from four individuals (including one with norwalk virus) and spice. phage typing confirmed all bacillus clinical isolates were phage type 2. all clinical isolates were subsequently identified as b. thuringiensis when tested as a result of a related study (l. leroux, person ...19957639990
structural analysis of inositol phospholipids from trypanosoma cruzi epimastigote forms.inositol phospholipids (ipl) from epimastigote forms of trypanosoma cruzi have been investigated by metabolic labelling with [3h]palmitic acid and by glc-ms analysis of the lipids obtained from non-labelled parasites. the ipl fraction was separated into phosphatidylinositol (pi) and inositol-phosphoceramide subfractions, the latter accounting for 80-85% of the total ipl. the neutral lipids released from the ipls by pi-specific phospholipase c (pi-plc) from bacillus thuringiensis were analysed by ...19957646454
the cryia(c) receptor purified from manduca sexta displays multiple specificities.the kinetic binding characteristics of four bacillus thuringiensis cryi insecticidal crystal proteins to a cry-binding protein, purified from manduca sexta brush-border vesicles, were analyzed by an optical biosensor. this 120-kilodalton binding protein, previously determined to be aminopeptidase n, was converted to a 115-kilodalton water-soluble form by removing the attached glycosylphosphatidylinositol anchor with phospholipase c. the solubilized form recognized the three major subclasses of c ...19957657602
adhesion and cytotoxicity of bacillus thuringiensis to cultured spodoptera and drosophila cells.two bacillus thuringiensis strains were tested for the ability to adhere to cultured spodoptera and drosophila insect cells. the wild-type strain is virulent and motile and readily adheres to and kills both types of insect cells. the avirulent mutant strain, which lacks flagella and several other of the proposed virulence factors, does not adhere to the insect cells and does not kill these cells efficiently. purified flagella bind to insect cells; addition of anti-flagella serum abolishes cell b ...19957658049
safety testing of bacillus thuringiensis preparations, including thuringiensin, using the salmonella assay.the aim of this study was to test genotoxicity aspects of the safety of two strains of bacillus thuringiensis. the strains were of serotype h-1, producing thuringiensin, toxic to flies, and serotype h-14, producing endotoxin, toxic to mosquitoes, but not thuringiensin. four preparations were tested: tenfold concentrated cell-free culture media of serotypes h-1 and h-14, prepurified thuringiensin, and purified endotoxin. no increases in revertant colony numbers of the tester strains of salmonella ...19957658050
a glycoprotein multimer from bacillus thuringiensis sporangia: dissociation into subunits and sugar composition.two glycoproteins (205 and 72 kda) were found in bacillus thuringiensis sporangia. they were predominantly localized in the exosporium and/or the spore coat, although a small proportion was also found in membranes. a method for the dissociation of hydrophobic aggregates that resist the usual conditions of sds-page is described. using this method we established that the 205 kda glycoprotein is a multimer of the 72 kda one. deglycosylation of the 205 kda and 72 kda glycoproteins with trifluorometh ...19957659076
domain organization of bacillus thuringiensis cryiiia delta-endotoxin studied by denaturation in guanidine hydrochloride solutions and limited proteolysis.denaturation of bacillus thuringiensis cryiiia delta-endotoxin--an insecticidal protein, active against coleoptera larvae--in concentrated guanidine hydrochloride solutions was pursued by fluorescence and circular dichroism spectroscopy and limited proteolysis. it was found that the protein consists of two fragments that differ by their stability to denaturation by guanidine hydrochloride at ph 3. the less stable fragment corresponds to the n-terminal alpha-helical domain limited by leu-279; the ...19957662112
deletion mutants of the gene encoding delta-endotoxin specific to scarabaeid beetles: minimum region of the gene required to express the activity.various deletion genes for the delta-endotoxin protein of bacillus thuringiensis strain buibui were made. the truncated proteins were produced in e. coli, and their larvicidal activity against the cupreous chafer was checked. the fifth block of the five blocks described as "conserved" was shown to be necessary for the activity.19957670204
expression and synergistic effect of three types of crystal protein genes in bacillus thuringiensis.bacillus thuringiensis nt0423 newly isolated from sericultural farms in korea produces quite atypical bipyramidal crystals of a common major band of ca. 130 kda, and has dual specificity against lepidoptera and diptera. to enforce the diptera toxicity of b. thuringiensis nt0423, cryivd and cyta genes were transformed into b. thuringiensis nt0423. the transformant b. thuringiensis pt0529 was obtained from introduction of pcg5 into b. thuringiensis nt0423 by electroporation. the expression of crys ...19957677771
in vitro binding of bacillus thuringiensis var. israelensis individual toxins to midgut cells of anopheles gambiae larvae (diptera: culicidae).midguts from anopheles gambiae fourth instars were dissected and processed for immuno-light microscopy. cloned insecticidal crystal proteins (icps) from bacillus thuringiensis var. israelensis (bti) were individually expressed in crystal-negative strains of bacillus thuringiensis. tissue sections of a. gambiae were incubated in vitro with each solubilized and trypsin-activated icp. immunodetection of cryiva, cryivb, cryivd and cyta toxins on sections was performed using purified rabbit igg direc ...19957720855
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 ...19957722082
the insecticidal cryib crystal protein of bacillus thuringiensis ssp. thuringiensis has dual specificity to coleopteran and lepidopteran larvae.the crystals found in sporulation extracts of bacillus thuringiensis (berliner) contain proteins that are highly toxic to insects. different crystal proteins exhibit distinct specificities for restricted groups of insects. an uncharacterized strain of b. thuringiensis (bts2), derived from china, was found to carry several crystal protein genes and to be toxic to a wide variety of insects, including some coleopterans. surprisingly, the coleopteran toxicity was traced to a cryib-class protein. the ...19957722342
random amplified polymorphic dna fingerprinting of mosquito-pathogenic and nonpathogenic strains of bacillus sphaericus.random amplified polymorphic dna fingerprinting was used to examine 31 mosquito-pathogenic and 14 nonpathogenic strains of bacillus sphaericus. we verified that dna bands that migrated the same distance in an agarose gel were homologous by using pcr-generated probes made from the random amplified polymorphic dna bands. the band patterns obtained with eight primers were analyzed by using the jaccard coefficient and unweighted pair group with arithmetic average clustering. pathogenic strains belon ...19957727272
single amino acid changes in domain ii of bacillus thuringiensis cryiab delta-endotoxin affect irreversible binding to manduca sexta midgut membrane vesicles.deletion of amino acid residues 370 to 375 (d2) and single alanine substitutions between residues 371 and 375 (fnigi) of lepidopteran-active bacillus thuringiensis cryiab delta-endotoxin were constructed by site-directed mutagenesis techniques. all mutants, except that with the i-to-a change at position 373 (i373a), produced delta-endotoxin as cryiab and were stable upon activation either by manduca sexta gut enzymes or by trypsin. mutants d2, f371a, and g374a lost most of the toxicity (400 time ...19957730254
transcriptional regulation of the cryivd gene operon from bacillus thuringiensis subsp. israelensis.the cryivd protein is involved in the overall toxicity of the bacillus thuringiensis subsp. israelensis parasporal inclusions and is one of the four major components of the crystals. determination of the dna sequence indicated that the cryivd gene is the second gene of an operon which includes three genes. the first one encodes a 19-kda polypeptide and has sequence homology with the orf1 gene of the bacillus thuringiensis cryiia and cryiic operons. the second and third genes have already been id ...19957730255
expression of the genes for insecticidal crystal proteins in bacillus thuringiensis: cryiva, not cryivb, is transcribed by rna polymerase containing sigma h and that containing sigma e.to investigate the mechanism of transcriptional regulation of cryiva and cryivb, encoding 130-kda dipteran-active crystal proteins, in bacillus thuringiensis subsp. israelensis, we introduced each gene into several sporulation mutants of bacillus subtilis. a spoiig mutation, the wild-type gene of which encodes sigma e precursor, completely blocked the cryivb transcription. in contrast, low but detectable transcription of cryiva was observed in the spoiig mutant. in the wild-type b. subtilis, no ...19957737485
kinetics of bacillus thuringiensis toxin binding with brush border membrane vesicles from susceptible and resistant larvae of plutella xylostella.an optical biosensor technology based on surface plasmon resonance was used to determine the kinetic rate constants for interactions between the cryia(c) toxin from bacillus thuringiensis and brush border membrane vesicles purified from susceptible and resistant larvae of diamondback moth (plutella xylostella). cryia(c) association and dissociation rate constants for vesicles from susceptible larvae were determined to be 4.5 x 10(3) m-1 s-1 and 3.2 x 10(-5) s-1, respectively, resulting in a calc ...19957744839
mosquito larvicidal activity of escherichia coli with combinations of genes from bacillus thuringiensis subsp. israelensis.the genes cryiva and cryivd, encoding 134- and 72-kda proteins, respectively, and the gene for a regulatory 20-kda polypeptide of bacillus thuringiensis subsp. israelensis (serovar h14) were cloned in all seven possible combinations by the escherichia coli expression vectors pt7 and puhe. the four combinations containing cryiva (cryiva alone, with cryivd, with the 20-kda-protein gene, and with both) displayed high levels of mosquito larvicidal activity in puhe. the toxicity of the combination of ...19957751296
the genetic basis of the aggregation system in bacillus thuringiensis subsp. israelensis is located on the large conjugative plasmid pxo16.the aggregation phenotypes agr+ and agr- of bacillus thuringiensis subsp. israelensis are correlated with a conjugation-like plasmid transfer and characterized by the formation of aggregates when the bacteria are socialized during exponential growth. we present evidence for the association of the agr+ phenotype with the presence of the large (135-mda) self-transmissible plasmid pxo16.19957751306
bacillus cereus phage typing as an epidemiological tool in outbreaks of food poisoning.bacillus cereus is responsible for an increasing number of food poisoning cases. by using 12 bacteriophages isolated from sewage, a typing scheme for b. cereus isolates from outbreaks or sporadic cases of food poisoning was developed. the phages belonged to three morphotypes. ten phages with contractile tails and icosahedral heads were members of the myoviridae family, and two phages with noncontractile tails belonged to the siphoviridae family. phage 11 represented a new species. it had an isom ...19957751369
membrane permeabilization by listeria monocytogenes phosphatidylinositol-specific phospholipase c is independent of phospholipid hydrolysis and cooperative with listeriolysin o.we have examined potential cooperative interactions of listeria monocytogenes phosphatidylinositol-specific phospholipase c (pi-plc) and listeriolysin o (llo), a pore-forming hemolysin, in a liposome lysis assay. large unilamellar vesicles, approximately 0.1 micron in diameter, encapsulating the fluorescent probe calcein, were treated with pi-plc or llo at ph 6.0, and each was capable of causing dye release. with phosphatidylcholine/phosphatidylinositol/cholesterol liposomes at 0.1 microm lipid, ...19957708759
bacillus thuringiensis protoxin: location of toxic border and requirement of non-toxic domain for high-level in vivo production of active toxin.insecticidal crystal proteins, or protoxins, of bacillus thuringiensis are composed of two domains, an amino-terminal half essential for toxicity, and a carboxy-terminal half with an as yet unassigned function. to define the boundary of the two domains, sequential termination codons were introduced from the 3'-end of the dna sequence encoding the toxic domain of the 1155-residue cry1a(b) gene product. the mutated and the intact genes were placed under the control of the escherichia coli inducibl ...19957711901
characterization of the bacillus anthracis s-layer: cloning and sequencing of the structural gene.bacillus anthracis, a gram-positive, spore-forming bacterium, is the etiological agent of anthrax. the gene coding for the s-layer protein (sap) was cloned on two contiguous fragments in escherichia coli, and the complete sequence of the structural gene was determined. the protein, sap, is composed of 814 residues, including a classical prokaryotic 29-amino-acid signal peptide. the mature form has a calculated molecular mass of 83.7 kda and a molecular mass of 94 kda on a sodium dodecyl sulfate- ...19957836294
nucleotide sequence of the gene encoding novel delta-endotoxin from bacillus thuringiensis serovar japonensis strain buibui specific to scarabaeid beetles.a new isolate of bacillus thuringiensis serovar japonensis strain buibui, which was specific to scarab beetles (m. ohba et al., lett. appl. microbiol. 14:54, 1992), was shown to have a 130-kda insecticidal crystal protein (icp) (h. hori et al., j. appl. bacteriol. 76:307, 1994). clai restriction enzyme fragments of total cell dna of the isolate were cloned into e. coli (sato et al., curr. microbiol. 28:15, 1994). whole 3480-bp nucleotide sequence of the gene encoding 130-kda icp was determined, ...19957765896
improved production of the insecticidal cryivd protein in bacillus thuringiensis using cryia(c) promoters to express the gene for an associated 20-kda protein.previous studies have shown that a 20-kda protein enhances production of the insecticidal cyta and cryiva proteins of bacillus thuringiensis in escherichia coli as well as cyta production and crystal formation in b. thuringiensis. to determine whether the 20-kda protein could enhance cryivd production, an expression vector was constructed with the 20-kda open-reading frame under control of cryia(c) promoters and the cryivd gene under control of its own promoter. acrystalliferous cells of b. thur ...19957765910
penicillin-g enhanced production of thuringiensin by bacillus thuringiensis sp. darmstadiensis.the effect of penicillin-g on the production of the potential microbial insecticide thuringiensin by bacillus thuringiensis sp. darmstadiensis was studied. shake flask and 3-l jar fermentor studies showed that the addition of 360 units/ml penicillin-g at 9 h, when the fermentable sugar in the medium was about to be mostly consumed, improved thuringiensin production by more than 1-fold relative to the control. the dosage of 360 units/ml penicillin-g had only a modest effect on the growth of the m ...19957766105
mapping and characterization of the entomocidal domain of the bacillus thuringiensis cryia(b) protoxin.the amino acid sequences necessary for entomocidal activity of the cryia(b) protoxin of bacillus thuringiensis were determined. introduction of stop codons behind codons arg601, phe604 or ala607 showed that amino acid residues c-terminal to ala607 are not required for insecticidal activity and that activation by midgut proteases takes place distal to ala607. the two shortest polypeptides, deleted for part of the highly conserved beta-strand, were prone to proteolytic degradation, explaining thei ...19957770056
bacillus thuringiensis protoxin: location of toxic border and requirement of non-toxin domain for high-level in vivo production of active toxin. 19957773421
structure, function and engineering of bacillus thuringiensis toxins.nature has provided potent insecticidal toxins as fermentation products of many bacillus thuringiensis strains. elucidation of structure-function relationships for this class of natural toxins is in its early stages. both direct experimentation and application of theoretical structure-function principles emerging from the rapidly growing field of protein structure are accelerating understanding of these toxins. coupled with the increasing demand for biologically sound pesticides, the benefits fr ...19957779517
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