Publications

TitleAbstractYear(sorted ascending)
Filter
PMID
Filter
structural and functional characterization of the alpha 5 segment of bacillus thuringiensis delta-endotoxin.one of the most conserved sequences in various delta-endotoxins is the 30 amino acid long block i. block i of cryiiia delta-endotoxin contains a 23 amino acid amphiphilic alpha-helix termed alpha 5. the potential involvement of this alpha 5 helix in the toxic mechanism of delta-endotoxin was examined. for this purpose, a peptide corresponding to the alpha 5 segment and its proline incorporated analogue (p-alpha 5) were synthesized and characterized. the alpha-helical content of the peptides, ass ...19938384882
a rapid and sensitive in vitro assay for the activity of bacillus thuringiensis delta-endotoxins.1. activated delta-endotoxins from bacillus thuringiensis strains toxic to lepidopteran larvae inhibit k(+)-dependent accumulation of amino acids into brush border membrane vesicles (bbmv) from the midgut of the susceptible species bombyx mori. 2. the activated toxins interfere with the k(+)-dependent uptake of histidine into bbmv only if they are effectively active in vivo. 3. to calculate ic50 values (the toxin concentration which determines 50% of the effect), dose-response curves were perfor ...19938384964
transcriptional regulation of bacillus thuringiensis subsp. israelensis mosquito larvicidal crystal protein gene cryiva.the cryiva gene encodes a component of the delta-endotoxin of bacillus thuringiensis subsp. israelensis. by s1 nuclease mapping and primer extension analysis, we have identified the transcriptional initiation site of cryiva. the transcriptional activity from the promoter was detected only for the sporulating cells more than 3 h after onset of the stationary phase. upstream from the cryiva transcriptional initiation site was found a nucleotide sequence partially homologous to the promoter consens ...19938386726
evidence that the putative cooh-terminal signal transamidase involved in glycosylphosphatidylinositol protein synthesis is present in the endoplasmic reticulum.nascent proteins destined to be processed to a glycosylphosphatidylinositol (gpi)-anchored membrane form contain nh2-terminal and cooh-terminal signal peptides. the first directs a nascent protein into the endoplasmic reticulum; the second peptide targets the protein to a putative cooh-terminal signal transamidase where cleavage of the peptide and addition of the gpi anchor occur. we recently showed that atp hydrolysis is required for maturation of gpi proteins at a stage prior to transamidation ...19938387204
[study of the nature of determinants for synthesis of delta-endotoxin and beta-exotoxin in bacillus thuringiensis subsp. thuringiensis strains--bitoxybacillin producers].the growth of bacillus thuringiensis subsp. thuringiensis strains (bt) 202, 1140, 98 producing bitoxybacillin in the presence of novobiocin, mitomycin c and at high temperature 43 degrees c resulted in obtaining of the mutants for the synthesis of crystalline protein (cry) and exotoxin (exo). analysis of the plasmid content of the mutants has shown the cry exo phenotyre to correlate with the loss of 55 md plasmid in the strain bt202 and the loss of 60md plasmid in bt1140. the transfer of these p ...19938389984
proof of alkaline phosphodiesterase i as a phosphatidylinositol-anchor enzyme.1. ectoenzyme release from kidney brush border membranes of rattus norvegicus and sus scrofa domesticus by phosphatidylinositol-specific phospholipase c (piplc) of bacillus thuringiensis was studied. 2. the levels of specific activities of ectoenzymes in r. norvegicus kidney brush border membranes were higher than those in s. scrofa domesticus. about 10-fold higher values were found for specific activities of alkaline phosphatase and gamma-glutamyl transpeptidase in r. norvegicus. 3. alkaline ph ...19938394252
[site-specific restriction endonuclease from the strain of bacillus thuringiensis var. kumantoensis]. 19938394507
substrate requirements of bacterial phosphatidylinositol-specific phospholipase c.a series of symmetric short-chain phosphatidylinositols (pi), including dihexanoyl-pi, diheptanoyl-pi (racemic as well as d and l forms), and 2-methoxy inositol-substituted diheptanoyl-pi, have been synthesized, characterized, and used to investigate key mechanistic questions about phosphatidylinositol-specific phospholipase c (pi-plc) from bacillus thuringiensis. key results include the following: (i) bacterial pi-plc exhibits a 5-6-fold "interfacial activation" when its substrate is present in ...19938395883
insertion sequence elements in bacillus thuringiensis subsp. darmstadiensis.two variants of insertion sequence is231, named is231g and h, were isolated from bacillus thuringiensis subsp. darmstadiensis 73-e-10-2 (btd2), an isolate toxic to dipteran insects, and characterized by dna sequence analysis. they are encoded consecutively as direct repeats on an ecori fragment of 5.6 kilo base pairs. direct tandem repeats of is231 elements have not been previously reported. both elements are closely related to other members of the is231 family that have been isolated from b. th ...19938395964
effects on toxicity of eliminating a cleavage site in a predicted interhelical loop in bacillus thuringiensis cryivb delta-endotoxin.when activated by treatment with mosquito (aedes aegypti) gut extract, the bacillus thuringiensis cryivb delta-endotoxin lysed a. aegypti cells in vitro. sds-page and n-terminal sequence determination showed that in addition to removal of the c-terminal half of the molecule, the activated toxin had undergone proteolytic cleavage at two internal regions producing 47-48-kda and 16-18-kda polypeptides. aligning the cryivb protein sequence with the crystallographic structure of the cryiiia toxin sug ...19938405934
mobilization of small plasmids in bacillus thuringiensis subsp. israelensis is accompanied by specific aggregation.mobilizations of pbc16 and pand006, containing the replicon of the bacillus thuringiensis subsp. israelensis plasmid ptx14-3, between strains of b. thuringiensis subsp. israelensis were examined. transconjugants appeared after a few minutes and reached a maximum frequency after approximately 2 h. plasmid pbc16 was mobilized at a frequency approximately 200 times that of pand006. however, pand006 was consistently transferred, suggesting that the replicon of ptx14-3 is sufficient to sustain mobili ...19938407829
site-directed mutations in a highly conserved region of bacillus thuringiensis delta-endotoxin affect inhibition of short circuit current across bombyx mori midguts.bacillus thuringiensis delta-endotoxins (cry toxins) are insecticidal proteins of approximately 65 kda in the proteolytically processed and active form. the structure of one of these toxins, cryiiia, has been determined by li et al. [li, j., carroll, j. & ellar, d. j. (1991) nature (london) 353, 815-821] and contains three domains. it is believed that other delta-endotoxins adopt similar three-dimensional structure. li et al. proposed that the first domain is the membrane pore-forming domain. pr ...19938415651
cloning and characterization of a novel bacillus thuringiensis cytolytic delta-endotoxin.a gene encoding a major entomocidal polypeptide from bacillus thuringiensis subspecies kyushuensis delta-endotoxin crystals (cytb) was cloned into escherichia coli and sequenced. the deduced amino acid sequence gave a predicted molecular mass of 29,236 da and showed 39% identity and 70% similarity with the 27,371 da cyta protein from bacillus thuringiensis subspecies israelensis. the larger size of cytb compared to cyta appears to be due to additional sequence in cytb after the cyta c-terminus. ...19938429550
a complete physical map of a bacillus thuringiensis chromosome.bacillus thuringiensis is the source of the most widely used biological pesticide, through its production of insecticidal toxins. the toxin genes are often localized on plasmids. we have constructed a physical map of a bacillus thuringiensis chromosome by aligning 16 fragments obtained by digestion with the restriction enzyme noti. the fragments ranged from 15 to 1,350 kb. the size of the chromosome was 5.4 mb. the noti dna fingerprint patterns of 12 different b. thuringiensis strains showed mar ...19938432698
multiplex polymerase chain reaction for detection and differentiation of the microbial insecticide bacillus thuringiensis.a rapid identification of bacillus thuringiensis strains was established by using multiplex polymerase chain reaction (pcr). primers of high homology specific to regions within genes encoding three major classes of b. thuringiensis crystal proteins were used to generate a pcr product profile characteristic of each strain of b. thuringiensis subsp. kurstaki. differentiation among these strains was made on the basis of the electrophoretic pattern of the pcr products. known b. thuringiensis subsp. ...19938434916
arbitrary primer polymerase chain reaction, a powerful method to identify bacillus thuringiensis serovars and strains.arbitrary primer polymerase chain reaction technology has been applied to the identification of commercial strains of bacillus thuringiensis by using total dnas extracted from single bacterial colonies as templates. characteristic dna banding patterns can be readily and reproducibly obtained by agarose gel electrophoresis. this method has been used to distinguish commercial products containing b. thuringiensis serovar kurstaki (3a3b). when a single primer was used this method was capable of prod ...19938439143
analysis of features contributing to activity of the single-stranded origin of bacillus plasmid pbaa1.the features which contribute to the activity of the single-stranded origin of the bacillus plasmid pbaa1 were investigated. this origin is contained on a dna fragment greater than 116 but less than 191 bases in size. there is the potential to form three stem-loop structures within this fragment. comparison of the sequence of this origin from pbaa1 with the sequence of a homologous fragment from the bacillus thuringiensis plasmid pgi2 indicates that both the structure and the relative positionin ...19938458841
evidence that the cryia crystal protein from bacillus thuringiensis is associated with dna.toxin generated by activation of the bacillus thuringiensis cryia(c) crystal protein (protoxin) with bovine trypsin was separated into two components by anion-exchange chromatography. one component (t2) was dna-associated toxin, and the other was the dna-free toxin (t1). only one major protoxin component was observed, and it was found to be associated with dna. the dna from the t2 toxin varied in size from 100 to 300 base pairs, whereas the crystal and the solubilized protoxin contained 20-kilob ...19938463332
membrane-bound choline-o-acetyltransferase in rat hippocampal tissue is anchored by glycosyl-phosphatidylinositol.in an earlier study, we presented evidence to suggest that some of the particulate choline-o-acetyltransferase (chat) in rat hippocampal tissue might be linked to membranes by a glycosyl-phosphatidylinositol (gpi) anchor. in the present report, we attempted to determine if any of this gpi-anchored chat might be intracellular. internalization of phosphatidylinositol-specific phospholipase c (pi-plc) from bacillus thuringiensis into rat hippocampal synaptosomes by the dmso (dimethyl sulfoxide) fre ...19938467384
analysis of common antigen of flagella in bacillus cereus and bacillus thuringiensis.flagellar antigen of bacillus cereus h.1 was purified and tested for serodiagnostic antigen by elisa. the antibody against the flagellar antigen of b. cereus h.1 reacted not only with the homologous specific antigen but also reacted with the flagellar antigens of 23 strains of b. cereus. this common flagellar antigen of b. cereus was found to be due to 61-kda protein by sds-page and immunoblot assay. monoclonal antibody h15a5 against common antigenic epitope of b. cereus also reacted with flagel ...19938472901
cloning of a novel cryic-type gene from a strain of bacillus thuringiensis subsp. galleriae.a novel cryic-type gene was isolated from a strain of bacillus thuringiensis subsp. galleriae. a new polymerase chain reaction (pcr) technique with a set of several oligonucleotide primer pairs specific to the cryic gene was used to screen a number of b. thuringiensis strains. pcr amplified several dna fragments ranging from 100 bp to 1 kb for b. thuringiensis strains containing a cryic gene. pcr fragments amplified from the bacillus thuringiensis subsp. galleriae hd29 dna differed from the frag ...19938476286
high-level cryivd and cyta gene expression in bacillus thuringiensis does not require the 20-kilodalton protein, and the coexpressed gene products are synergistic in their toxicity to mosquitoes.interactions among the 20-kda protein gene and the cyta and cryivd genes located in a 9.4-kb hindiii fragment were studied. a series of plasmids containing a combination of these different genes was constructed by using the escherichia coli/bacillus thuringiensis shuttle vector pht3101. the plasmids were then used to transform an acrystalliferous strain, cryb, derived from b. thuringiensis subsp. kurstaki. the results from sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblot ...19938481007
effect of bacteriophage lysogeny on the efficacy of two bacterial larvicide formulations under field conditions.two types of man-made ditches were selected for carrying out this experiment; one polluted with nitrogenous matters (sewage water) and second filled with accumulated irrigated clear non-chlorinated water. no phages were detected in samples collected from both types of ditches. however, phage(s) specific to only b. sphaericus was (were) detected after spraying the two types with both b. thuringiensis h-14 and b. sphaericus commercial formulations. the detection of phage(s) was observed after 3 da ...19938482880
in vitro and in vivo proteolysis of the bacillus thuringiensis subsp. israelensis cryivd protein by culex quinquefasciatus larval midgut proteases.proteases with trypsin-, chymotrypsin- and thermolysin-like specificity were detected in culex quinquefasciatus larval midguts. their activities were monitored by n-terminal amino acid sequence analysis of the bacillus thuringiensis subsp. israelensis cryivd toxin proteolytic fragments. these proteases are located in the larval midgut and in different fractions obtained during the preparation of brush border membrane vesicles. the activity of the midgut proteases increased with an increase in ph ...19938485524
the reconstruction and expression of a bacillus thuringiensis cryiiia gene in protoplasts and potato plants.a bacillus thuringiensis (b.t.) cryiiia delta-endotoxin gene was designed for optimal expression in plants. the modified cry gene has the codon usage pattern of an average dicot gene and does not contain at-rich nucleotide sequences typical of native b.t. cry genes. we assembled the 1.8 kb cryiiia gene in nine blocks of three oligonucleotide pairs. for two dna blocks, the polymerase chain reaction was used to enrich for correctly ligated pairs. we compared modified cryiiia gene with native gene ...19938490132
full expression of the cryiiia toxin gene of bacillus thuringiensis requires a distant upstream dna sequence affecting transcription.the cryiiia gene encoding a coleopteran-specific toxin is poorly expressed in bacillus thuringiensis when cloned in a low-copy-number plasmid. this weak expression is observed when the gene is cloned only with its promoter and its putative terminator. cryiiia gene expression was analyzed by using deletion derivatives of a larger dna fragment carrying the toxin gene and additional adjacent sequences. the results indicate that a 1-kb dna fragment located 400 bp upstream of the promoter strongly en ...19938491716
[studies on insecticidal ingredients from culture supernatant of bacillus thuringiensis].studies on the insecticidal activity of culture supernatant of bacillus thuringiensis var. kurstaki hd-1, by centrifugation, column chromatography, protein sequence determination, bioassay and other methods. found that insecticidal activity of culture supernatant appeared on synchronism with cells lysis. main insecticidal ingredients of culture supernatant is toxin protein of 60 kilodaltons (kda). analyse hat purified the toxin protein, we find that its amino acid composition was similar with 13 ...19938503203
genetically improved potatoes: protection from damage by colorado potato beetles.russet burbank potato plants have been genetically improved to resist insect attack and damage by colorado potato beetles (leptinotarsa decemlineata (say)) by the insertion of a cryiiia gene encoding the insect control protein of bacillus thuringiensis var. tenebrionis. a modified gene that dramatically improved plant expression of this protein was utilized. its expression in russet burbank potato plants resulted in protection from damage by all insect stages in the laboratory and in dramatic le ...19938507832
a specific binding protein from manduca sexta for the insecticidal toxin of bacillus thuringiensis subsp. berliner.biopesticides based on the bacterium bacillus thuringiensis have attracted wide attention as safe alternatives to chemical pesticides. in this paper, we report, for the first time, the identification and purification of a single binding protein from a lepidopteran insect, manduca sexta, that is specific for a cryia toxin of b. thuringiensis. the purified protein appeared as a single band of 210 kda on a two-dimensional gel, had a pi of approximately 5.5, and stained with schiff's reagent. the ba ...19938509372
[structural and molecular-biological characteristics of a new transducing phage from bacillus thuringiensis tt 91].a new bacteriophage tt91 of larger size and broad lytical spectrum has been isolated from soil to widen the possibility to study new bacillus thuringiensis strains. the tt91 bacteriophage was shown to perform the intravariant transduction and, thus, can be used for genetic mapping. the ultrastructural analysis made it possible to refer bacteriophage tt91 to morphotype a1 and showed similarity of tt91 morphological structure to the one of cp-group bacteriophages. the performed comparative analysi ...19938510683
screening by polymerase chain reaction of bacillus thuringiensis serotypes for the presence of cryv-like insecticidal protein genes and characterization of a cryv gene cloned from b. thuringiensis subsp. kurstaki.polymerase chain reaction screening using cryv-specific oligonucleotides, designed to amplify the 5' half of cryv-type genes, revealed the presence of such genes in 7 of 21 bacillus thuringiensis serotypes examined. restriction analysis and hybridization studies indicated that these putative genes fall into at least three subclasses. the nucleotide sequence of the cryv-type gene cloned from b. thuringiensis subsp. kurstaki dsir732 revealed an open reading frame coding for a protein of 719 amino ...19938517758
effect of rice husbandry on mosquito breeding at mwea rice irrigation scheme with reference to biocontrol strategies.a study was carried out at mwea rice irrigation scheme, kenya, to assess the impact of rice husbandry on mosquito breeding and identify indigenous biocontrol agents with potential for controlling mosquito breeding in the scheme. the study established a close relationship between the schedule of the farming practices (particularly the flooding phase) and mosquito breeding. two groups of agents, entomopathogenic bacteria (bacillus thuringiensis var. israelensis) and larvivorous fish, were identifi ...19938096871
application of bactoculicide (bacillus thuringiensis h-14) for controlling mosquito breeding in industrial scrap at bhel, hardwar (u.p.).bactoculicide (bacillus thuringiensis) was evaluated in field trials for controlling mosquito breeding of aedes, culex and anopheles in industrial scraps such as broken heavy machine parts, iron moulds and discarded drums. a dose of 0.5 g/m2 was controlled 96-100% mosquito breeding up to five weeks.19938100539
effect of temperature on toxicity of two bioinsecticides spherix (bacillus sphaericus) and bactoculicide (bacillus thuringiensis) against larvae of four vector mosquitoes.two bioinsecticide preparations, viz. spherix (bacillus sphaericus) and bactoculicide (bacillus thuringiensis h-14), were tested in the laboratory against larvae of anopheles culicifacies, anopheles stephensi, culex quinquefasciatus and aedes aegypti at different temperatures. the lcs50 of spherix against iii instar larvae of these species at 27 +/- 2 degrees c were 2.0, 0.19, 0.05 and > 40 mg/litre, respectively and those of bactoculicide were 0.32, 0.16, 0.06 and 0.03 mg/litre, respectively. t ...19938100540
[the efficacy of the biological insecticide blp with regard to the larvae of blood-sucking mosquitoes in uzbekistan].the efficacy of a biologic larvicidal preparation blp was under study; the insecticide was prepared on the basis of a new strain of b. thuringiensis var. israilensis h-14, isolated from natural material, and its activity to ae. caspiens, c. pipiens, an. hyrcanus larvae was examined. the minimal effective dose of blp used for the treatment of various water bodies is 0.5 kg per 10,000 m2. blp is permitted by the ministry of health and the ministry of fishery of the russian federation for mosquito ...19938101630
[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 ...19938178516
transcriptional regulation of the bacillus thuringiensis subsp. thompsoni crystal protein gene operon.the two predominant polypeptides of the bacillus thuringiensis subsp. thompsoni crystal are encoded by the cry40 and cry34 genes. these crystal protein genes are located in an operon. western analysis (immunoblotting) demonstrated that the operon promoter activity was located in the region upstream of the cry40 gene. the cry34 protein was expressed only when the upstream promoter region was present. the crystal protein genes are the only cistrons in the operon, and they are expressed during spor ...19937504667
lepidopteran-specific crystal toxins from bacillus thuringiensis form cation- and anion-selective channels in planar lipid bilayers.previous studies in our laboratory have shown that cryic, a lepidopteran-specific toxin from bacillus thuringiensis, triggers calcium and chloride channel activity in sf-9 cells (spodoptera frugiperda, fall armyworm). chloride currents were also observed in sf-9 membrane patches upon addition of cryic toxin to the cytoplasmic side of the membrane. in the present study the ability of activated cryic toxin to form channels was investigated in a receptor-free, artificial phospholipid membrane syste ...19937681482
effect of promoter modification on mosquitocidal cryivb gene expression in synechococcus sp. strain pcc 7942.the impact of promoter modification on the expression of the mosquitocidal bacillus thuringiensis subsp. israelensis cryivb gene when used to transform the cyanobacterium synechococcus sp. strain pcc 7942 has been examined. maximal transcript and protein abundances were achieved by the addition of the lacz promoter upstream of the cryivb sequence. replacement of the endogenous corresponding bacillus sequences with the synechococcus petf1 promoter, ribosome binding site, and initiation codon also ...19937690220
characterization of an avirulent pleiotropic mutant of the insect pathogen bacillus thuringiensis: reduced expression of flagellin and phospholipases.an avirulent pleiotropic mutant of the insect pathogen bacillus thuringiensis subsp. gelechiae, isolated by heierson et al. (a. heierson, i. sidén, a. kivaisi, and h. g. boman, j. bacteriol. 167:18-24, 1986) as a spontaneous phage-resistant mutant, was further characterized and found to lack the expression of phosphatidylcholine- and phosphatidylinositol-degrading phospholipase c, beta-lactamase, and flagellin because of the absence of corresponding mrnas. the avirulent mutant was also found to ...19937693592
ion channel activity of n-terminal fragments from cryia(c) delta-endotoxin.proteolytically-derived amino-terminal fragments from the bacillus thuringiensis delta-endotoxin, cryia(c), demonstrated ion channel activity in two in vitro assays in the absence of any membrane receptors. a 24.5 kda fragment (from spodoptera frugiperda digestive proteolysis) formed cation-selective channels (10mv for a 3:1 salt gradient) in planar lipid bilayers up to several hundred picosiemen conductance. a 21.5 kda fragment doublet (from alkaline hydrolysis) also showed large conductance in ...19937694582
importance of the central region of 130-kda insecticidal proteins of bacillus thuringiensis var. israelensis for their activity in vivo and in vitro.to delineate the mosquitocidal regions of the isrh3 (cryivb) and isrh4 (cryiva) proteins, which are two of the mosquitocidal 130-kda proteins contained in the crystalline protein bodies (cpbs) of bacillus thuringiensis var. israelensis (bti), a deletion analysis of these protein genes has been done. based on the evidence that each 130-kda protein had two mosquitocidal regions, n-terminal and c-terminal ones, and these two regions shared a common part in the center of the 130-kda proteins, delete ...19937765303
insect resistant rice generated by introduction of a modified delta-endotoxin gene of bacillus thuringiensis.as a first step towards development of insect resistant rice we have introduced a truncated delta-endotoxin gene, cryia(b) of bacillus thuringiensis (b.t.) which has specific biological activity against lepidopteran insects into a japonica rice. to highly express the cryia(b) gene in rice the coding sequence was extensively modified based on the codon usage of rice genes. transgenic plants efficiently expressed the modified cryia(b) gene at both mrna and protein levels. bioassays using r2 genera ...19937764096
[the acute toxicity of a bacterial insecticidal preparation containing a beta-exotoxin].the acute toxicity of a new bulgarian bioinsecticide preparation is determined, produced on the basis of bacillus thuringiensis containing 0.1% beta-exotoxin by oral, dermal, inhalational and intraperitoneal introduction in experimental animals. the evaluation of the toxicity is performed by a complex of toxicometric, integral, haematologic and pathologicoanatomic methods according to the who and usa criteria for studying the safety of the microbic agents for plant protection. it is already esta ...19937845961
diversity of bacillus thuringiensis environmental isolates showing larvicidal activity specific for mosquitoes.seven mosquito-specific strains of bacillus thuringiensis isolated in japan were examined for their flagellar (h) antigenicities and the properties of parasporal inclusion proteins. they were assigned to six h serovars: serovar fukuokaensis (h 3ade); serovar canadensis (h 5ac); serovar darmstadiensis (h 10); serovar kyushuensis (h 11ac); serovar shandongiensis (h 22); and an undescribed serovar belonging to h serotype 20. purified parasporal inclusions exhibited moderate mosquito larvicidal acti ...19937903978
alkaline phosphodiesterase i release from eucaryotic plasma membranes by phosphatidylinositol-specific phospholipase c. iii. the release from tumor cells.1. alkaline phosphodiesterase i release from two tumor cell lines, kb iii or ah-130 cells, by the action of phosphatidylinositol-specific phospholipase c (piplc) of bacillus thuringiensis was studied. 2. a significant amount of alkaline phosphodiesterase i was released from both the cell suspension and homogenate of kb iii cells, but not from ah-130 cells. 3. the release of the enzyme from kb iii cells was dependent on, or proportional to, the reaction time and the piplc or cell concentrations. ...19937904575
mosquitocidal toxins of bacilli and their genetic manipulation for effective biological control of mosquitoes.the identification, cloning, and characterization of protein toxins from various species of bacilli have demonstrated the existence of mosquitocidal toxins with different structures, mechanisms of action, and host ranges. a start has been made in understanding the polypeptide determinants of toxicity and insecticidal activity, and the purification of toxins from recombinant organisms may lead to the elucidation of their x-ray crystal structures and the cloning of brush border membrane receptors. ...19937905597
resistance to toxins from bacillus thuringiensis subsp. kurstaki causes minimal cross-resistance to b. thuringiensis subsp. aizawai in the diamondback moth (lepidoptera: plutellidae).repeated exposure in the field followed by laboratory selection produced 1,800- to >6,800-fold resistance to formulations of bacillus thuringiensis subsp. kurstaki in larvae of the diamondback moth, plutella xylostella. four toxins from b. thuringiensis subsp. kurstaki [cryia(a), cryia(b), cryia(c), and cryiia] caused significantly less mortality in resistant larvae than in susceptible larvae. resistance to b. thuringiensis subsp. kurstaki formulations and toxins did not affect the response to c ...199316348929
biotinylation of bacillus thuringiensis insecticidal crystal proteins.biotinylation of bacillus thuringiensis insecticidal crystal proteins (icps) was evaluated for its potential use in an alternative icp screening method and in the characterization of icp receptors. in vivo biological activity of cryia(b), as inferred from bioassays with manduca sexta and ostrinia nubilalis and from histopathological effects on o. nubilalis midgut cells induced by force feeding, was not affected by biotinylation at moderate biotinylation ratios. a competitive radioreceptor assay ...199316348959
two different bacillus thuringiensis delta-endotoxin receptors in the midgut brush border membrane of the european corn borer, ostrinia nubilalis (hübner) (lepidoptera: pyralidae).binding of three bacillus thuringiensis insecticidal crystal proteins (icps) to the midgut epithelium of ostrinia nubilalis larvae was characterized by performing binding experiments with both isolated brush border membrane vesicles and gut tissue sections. our results demonstrate that two independent icp receptors are present in the brush border of o. nubilalis gut epithelium. from competition binding experiments performed with i-labeled and native icps it was concluded that cryia(b) and cryia( ...199316348960
nonenzymatic glycosylation of lepidopteran-active bacillus thuringiensis protein crystals.we used high-ph anion-exchange chromatography with pulsed amperometric detection to quantify the monosaccharides covalently attached to bacillus thuringiensis hd-1 (dipel) crystals. the crystals contained 0.54% sugars, including, in decreasing order of prevalence, glucose, fucose, arabinose/rhamnose, galactose, galactosamine, glucosamine, xylose, and mannose. three lines of evidence indicated that these sugars arose from nonenzymatic glycosylation: (i) the sugars could not be removed by n- or o- ...199316349021
expression of cryiva and cryivb genes, independently or in combination, in a crystal-negative strain of bacillus thuringiensis subsp. israelensis.the cryiva and cryivb genes, encoding the 125- and 135-kda proteins, respectively, of bacillus thuringiensis subsp. israelensis, were cloned either alone or together into a shuttle vector and expressed in a nontoxic strain of b. thuringiensis subsp. israelensis. the cryivb protein was produced at a high level during sporulation and accumulated as inclusions; in contrast, the cryiva polypeptide did not form such structures unless it was cloned on a higher-copy-number plasmid. transcriptional fusi ...199316349095
production of bacillus thuringiensis spores in total cell retention culture and two-stage continuous culture using an internal ceramic filter system.the production of bacillus thuringiensis spores was investigated in a bioreactor incorporating a ceramic membrane filter to improve spore concentration and volumetric productivity. two cultivation methods were used in this study: a total cell retention culture (tcrc), and a two-stage continuous culture with partial cell bleeding. in the tcrc, fed by 50 g/l of glucose, a spore concentration of 1.6 x 10(10) cfu/ml was obtained with a spore percentage of greater than 95% and a maximum cell mass of ...199318613240
transformation of liquidambar styraciflua using agrobacterium tumefaciens.we describe the molecular transformation of liquidambar styraciflua using agrobacterium tumefaciens. a binary ti-plasmid vector containing a chimeric neomycin phosphotransferagene which confers resistance to kanamycin and either a chimeric bacillus thuringiensis toxin gene, a chimeric e. coli β-glucuronida(gus), or a chimeric tobacco anionic peroxidase gene was introduced into sweetgum by co-cultivation with agrobacterium tumefaciens. sweetgum shoots regenerated in the presence of kanamycin were ...199324197252
algae in mosquito breeding sites and the effectiveness of the mosquito larvicide bacillus thuringiensis h-14.the presence of cyanobacteria generally decreased the effectiveness of bacillus thuringiensis h-14 (bti) as a mosquito larvicide. the effect was more pronounced when the mosquito larvae were exposed to bti in the presence of several cyanobacterial strains. no synergistic or antagonistic effect between the δ-endotoxin from bti and the hepatotoxin from cyanobacteria was seen. neurotoxic cyanobacterial strains caused very fast paralysis in mosquito larvae; the decreases in the effectiveness of bti ...199324419936
specific toxicity of δ-endotoxins from bacillus thuringiensis to bombyx mori.two δ-endotoxins, cryia(a) and cryia(b), from bacillus thuringiensis subsp.. aizawai were used to investigate the specificity in insecticidal activity. cryia(a) was 17-fold more toxic to bomhyx mori than cryia(b). after in vitro solubilization and digestion of these δ-endotoxins, the specificity of toxicity was retained. trypsin-activated cryia(a) and cryia(b) showed specific, high affinity and saturable binding to brush border membrane vesicles (bbmv) from b. mori midguts. these two toxins comp ...199327314769
binding of an engineered 130-kda insecticidal protein of bacillus thuringiensis var. israelensis to insect cell lines. 199327281006
use of an operon fusion to induce expression and crystallisation of a bacillus thuringiensis delta-endotoxin encoded by a cryptic gene.a delta-endotoxin gene previously cloned from bacillus thuringiensis subsp. galleriae has been shown by a combination of restriction mapping and dna sequence analysis to be a cryiib clone; in common with other cryiib genes it was found to lack a functional promoter. addition of a promoter resulted in expression of the gene in bacillus thuringiensis but did not result in the formation of the crystalline inclusions normally associated with such toxins. inclusion formation was only observed when th ...19947906381
the receptor for bacillus thuringiensis cryla(c) delta-endotoxin in the brush border membrane of the lepidopteran manduca sexta is aminopeptidase n.a 120 kda glycoprotein in the larval midgut membrane of the lepidopteran manduca sexta, previously identified as a putative receptor for bacillus thuringiensis cryla(c) delta-endotoxin, has been purified by a combination of protoxin affinity chromatography and anion exchange chromatography. in immunoblotting experiments, the purified glycoprotein has the characteristics predicted of the receptor: it binds cryla(c) toxin in the presence of glcnac but not galnac; it binds the lectin sba; but it do ...19947908713
incorporation of body components of diverse microorganisms by larval mosquitoes.a pulse-purge schedule of exposure to labeled microorganisms was used to compare their digestibility by larval mosquitoes. larvae were placed for an hour in suspensions of diverse axenically grown microorganisms that had been labeled with radioactive carbon (in the form of glucose or glycine). the guts of these mosquitoes were then purged with nonlabeled sephadex particles for 30 min, and retained radioactivity was measured. larvae imbibed no dissolved material. larval mosquitoes differ in their ...19947912260
characterization of bacillus thuringiensis and related bacteria by ribosomal rna gene restriction fragment length polymorphisms.ribosomal rna gene restriction patterns have been determined for 43 strains of bacillus thuringiensis representing 10 serovars and eight reference strains of b. anthracis, b. cereus and b. mycoides. strains within a b. thuringiensis serovar produced highly related or identical ribotype patterns: in particular, 12 strains of serovar israelensis, five strains of serovar kurstaki, two strains of serovar galleriae and three strains of serovar aizawa produced ribotype patterns consistent with serotyp ...19947912979
functional analysis of block 5, one of the highly conserved amino acid sequences in the 130-kda cryiva protein produced by bacillus thuringiensis subsp. israelensis.there are five amino acid sequences highly conserved among bacillus thuringiensis delta-endotoxins. we have changed the amino acid residues in block 5, one of the conserved sequences, of cryiva. when the amino acid residues with charged side chains were replaced by others, the amount of production of the altered cryiva protein was markedly decreased. it is suggested that the decrease is caused by the unstable conformation of the altered cryiva protein molecule, as judged by digestion with trypsi ...19947913448
[comparative effectiveness of bacterial larvicides against mosquito and bloodsucking midges]. 19947915702
structural and functional studies of a synthetic peptide mimicking a proposed membrane inserting region of a bacillus thuringiensis delta-endotoxin.in order to study the mechanism of action of bacillus thuringiensis delta-endotoxins, a synthetic 31-mer peptide corresponding to the sequence of a putative pore-forming segment of the cryla(c) toxin was characterized structurally and functionally. the peptide maps onto the central helix (alpha 5) of the six-helix bundle of domain i of the crystal structure of the cryiiia toxin. cd and nmr spectroscopic studies indicated that the peptide exists as an alpha-helix in methanol and a random coil in ...19947920867
biochemical characterization of bacillus thuringiensis cytolytic delta-endotoxins.the entomocidal delta-endotoxins cyta and cytb produced by bacillus thuringiensis (bt) subspecies israelensis and kyushuensis respectively showed a similar level of toxicity to mosquito larvae but were not toxic to the larvae of the lepidopteran manduca sexta. cyta and cytb are also similar in sequence, predicted secondary structure and alpha-helical content, the only obvious difference being a c-terminal fifteen residue 'tail' on cytb. investigations of the function, if any, of the cytb c-termi ...19947921240
survival and respiratory activity of genetically engineered pseudomonas spp. exposed to antimicrobial agents in broth and soil.the effectiveness of seven chemical disinfectants were tested against genetically engineered pseudomonas spp. under optimal growth conditions. each chemical was tested to determine how quickly 10(8) cells/ml pseudomonas fluorescens c5t (containing bacillus thuringiensis endotoxin gene) were killed in king's b broth at 30 degrees c. the minimal bactericidal concentrations (mbc) for calcium hypochlorite, benzalkonium chloride, germiphene and spectrum clear bath were 0.06% (w/v), 0.01% (w/v), 0.08% ...19947921352
distribution of endogenous and exogenous 5'-nucleotidase on bovine spermatozoa.a polyclonal rabbit antibody against 5'-nucleotidase purified from bull seminal plasma was used to localize the antigen on bovine spermatozoa. spermatozoa taken from the ampulla of the vas deferens showed strong immunofluorescence at the anterior rim of the head portion. evaluation of spermatozoa prepared from different segments of the seminal pathway indicated the presence of the antigen already in rete testis and epididymal spermatozoa. on cryostat sections of testis tissue a positive immunore ...19947928408
insect resistance of transgenic plants that express modified bacillus thuringiensis cryia(b) and cryic genes: a resistance management strategy.tobacco and tomato plants were generated exhibiting insect resistance due to the introduction of modified cryia(b) and cryic genes of bacillus thuringiensis. limited modifications at selected regions of the coding sequences of both genes are sufficient to obtain resistance against spodoptera exigua, heliothis virescens and manduca sexta. the criteria used to modify both genes demonstrate that the removal of sequence motifs potentially resulting in premature polyadenylation and transcript instabi ...19947948900
a comparison and analysis of the toxicity and receptor binding properties of bacillus thuringiensis cryic delta-endotoxin on spodoptera littoralis and bombyx mori.the binding of l-[35s]methionine in vivo labelled cryic toxin to its receptor in brush border membrane vesicle (bbmv's) prepared from spodoptera littoralis and bombyx mori was studied. both insect species were highly susceptible to the cryic toxin in bioassays, b. mori being 7-fold more sensitive to cryic than s. littoralis (lc50's of 10 ng/cm2 and 70 ng/cm2, respectively). competition and direct binding experiments revealed saturable high-affinity binding sites on bbmv's from both insects which ...19947957870
characterization of the type strain of bacillus thuringiensis subsp. cameroun serotype h32.the strain 273 b, the type strain of a h serotype of bacillus thuringiensis not yet characterized: b. thuringiensis subsp. cameroun, serotype h32, was isolated from soil samples collected in cameroon. this strain produces cuboidal parasporal bodies composed of two major proteins of 53 kda and 35 kda. n-terminal sequences of the major proteins share no homology with published sequences. only the 35 kda protein is susceptible to digestion by trypsin. a complex array of 9 plasmids was revealed.19947958777
crystallization and preliminary x-ray diffraction studies of the lepidopteran-specific insecticidal crystal protein cryla(a).a trypsin-activated cryla(a) protein from bacillus thuringiensis has been purified and crystallized. crystals belong to orthorhombic space group p2(1)2(1)2(1), with cell dimensions a = 53.3, b = 111.3 and c = 154.7 a. the crystals diffract to at least 2.2 angstrum resolution and are suitable for x-ray structural analysis. they contain a single molecule in the asymmetric unit.19947966278
role of the exosporium in the stability of the bacillus sphaericus binary toxin.the persistence of toxicity of the bacillus sphaericus 1593 binary toxin was compared when produced in b. sphaericus, inside the exosporium, or in a recombinant b. thuringiensis strain, outside the exosporium. the stability of the toxin crystal was affected by temperature and quality of the water, but not by the location of the production in the bacterial cell.19947851734
the safety of bacillus species as insect vector control agents. 19947499181
a modified bioassay for microbial mosquito larvicides.the proposed bioassay-the grid assay-eliminates the influence of cannibalism while allowing recycling to take place. the lc50 values of the grid assay were intermediate to those of the group and the individual assay. the grid assay thus reflects the true toxicity values of the microbial pesticides being tested. viable count studies of the microbial pesticides employed, viz., bacillus thuringiensis h-14 and bacillus sphaericus 2362, performed along with the assay support the results of the bioass ...19947896324
[testing effectiveness of selected bio-insecticides for reducing the population of cockroaches (blattella germanica l.)].the usefulness was tested of the biological insecticides containing b. thuringiensis available in the market in the eradication of cockroaches. thuridan was the most effective out of the tested insecticides in reducing the number of the insects. its higher activity in relation to thuricide was evident at all tested concentrations. males were more sensitive than females. on the other hand, no significant response of cockroaches to m-one preparation was noted, since the per cent of dying insects w ...19947878338
[studies on the ecological distribution of bacillus thuringiensis in forest soils of china].a total of 384 forest soils samples at 0-5cm depth collected from 8 forest site zones (13 natural reserves) in china were examined for the distribution of bacillus and bacillus thuringiensis. the 79 cultures (4.21%) in 1873 isolates of bacillus collected referable to the bacillus thuringiensis. soil ph, moisture content and soil nutrient were determined. rules of the ecological distribution of bacillus thuringiensis of 8 forest site zones in china were analysed. toxicities against 6 species of i ...19947879387
biochemical and morphological changes in rat muscle cultures caused by 28,000 mol. wt toxin of bacillus thuringiensis israelensis.the 28,000 mol. wt protein of bacillus thuringiensis israelensis showed a high degree of toxicity to rat muscle in culture. application of 1 microgram/ml to the culture medium completely inhibited cell fusion. reversibility of this effect was demonstrated by replacement of the culture medium with fresh medium, and the consequence was that cell fusion was resumed. when differentiated myotubes were treated with 1 microgram/ml of the toxin, the spontaneous contractile activity was abolished within ...19947801348
coleopterancidal delta-endotoxin and constructing its genomic library.the composition of crystal proteins and plasmid patterns in five new coleopterancidal strains of bacillus thuringiensis were investigated. larvae of plagiodera versicolora were chosen as a model insect in bioassay. strain ym-03 had the highest toxicity. plasmid patterns were detected by rapid agarose gel electrophoresis. it was demonstrated that plasmid patterns of five bt strains were quite different. the partial amino acid sequences of the n-terminal of crystal protein from ym-03 were analyzed ...19947803692
[bioassays with entomopathogenic bacteria]. 19947838980
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 ...19947842169
dengue vector control: present status and future prospects.dengue fever (df) and dengue haemorrhagic fever (dhf) have been the most common urban diseases in southeast asia since the 1950s. more recently, the diseases have spread to central and south america and are now considered as worldwide diseases. both aedes aegypti and aedes albopictus are involved in the transmission of df/dhf in southeast asian region. the paper discusses the present status and future prospects of aedes control with reference to the malaysian experience. vector control approache ...19947844836
synergism of mosquitocidal toxicity between cyta and cryivd proteins using inclusions produced from cloned genes of bacillus thuringiensis.the toxicity to mosquito larvae of the parasporal body produced by bacillus thuringiensis subsp. israelensis and the pg-14 isolate of b. thuringiensis subsp. morrisoni is at least 20-fold greater than any of the four mosquitocidal proteins of which it is composed (cyta, cryiva, b, and d). this high toxicity is postulated to be due to synergistic interactions among parasporal proteins. however, this remains controversial because values reported for the specific toxicity of individual proteins, es ...19947854129
cloning, heterologous expression, and localization of a novel crystal protein gene from bacillus thuringiensis serovar japonensis strain buibui toxic to scarabaeid insects.recombinant escherichia coli strains harboring pag1, pag2, pkbb100, and pkbb101 were cloned by using antiserum constructed against 130-kda crystal protein antigen of bacillus thuringiensis serovar japonensis strain buibui. dnas in the recombinant strains hybridized to the 26-base oligonucleotide probe corresponding to n-terminal amino acids of the 130-kda crystal protein of strain buibui. cultures of the recombinant strains were toxic to larvae of the cupreous chafer, anomala cuprea. furthermore ...19947764305
genetic engineering on bacillus thuringiensis insecticidal proteins. 19947764780
cloning of a new cryia(a) gene from bacillus thuringiensis strain fu-2-7 and analysis of chimaeric cryia(a) proteins for toxicity.we cloned the cryia(a) gene from bacillus thuringiensis strain fu-2-7, one of the toxin genes encoding lepidopteran-specific protoxins. sequence analysis of the gene showed two amino acid differences (pro77 to leu and phe965 to ser) from the cryia(a) of b. thuringiensis strain hd-1. we constructed chimaeric cryia(a) genes using fu-2-7 and hd-1 cryia(a) genes and isolated the chimaeric protoxins, as well as the parental ones, from escherichia coli cells harboring the recombinant plasmids to exami ...19947764972
current research to develop the entomopathogen bacillus thuringiensis for horn fly control.bacillus thuringiensis subspecies israelensis (bti) has been shown to produce at least two sporulation-specific proteins which result in larvicidal activity when incorporated in bioassays against horn flies (haematobia irritans l.). development of a new control technology for horn flies based on bti appears to be feasible through the use of recombinant dna technology. substantial work remains however, to develop new research tools and techniques for this application.19947765154
recombinant bacillus thuringiensis crystal proteins with new properties: possibilities for resistance management.to obtain bacillus thuringiensis crystal proteins with new properties and to identify the regions involved in insecticidal activity, we generated hybrid genes composed of cryic and cryie by in vivo recombination. analysis of the hybrid proteins showed that domain iii of cryic is involved in the toxicity towards spodoptera exigua and mamestra brassicae. transfer of this domain to cryie, which is not active against these insects, resulted in a new protein with a broader activity. this hybrid prote ...19947765229
integrated management of waste tire mosquitoes utilizing mesocyclops longisetus (copepoda: cyclopidae), bacillus thuringiensis var. israelensis, bacillus sphaericus, and methoprene.this study evaluated the compatibility and efficacy of using a predatory copepod, mesocyclops longisetus in concert with 3 "biorational" compounds for mosquito control in waste tires. the toxicity of bacillus thuringiensis var. israelensis (b.t.i), bacillus sphaericus, and methoprene to mesocyclops longisetus was assessed in the laboratory using concentrations 10 times the maximum labeled or suggested rate and based on a water depth of 7.6 cm. microbials were tested using mature copepods exposed ...19947807078
emergency control of aedes aegypti in the dominican republic using the scorpion 20 ulv forced-air generator.in an effort to develop a more effective measure for use in emergency control of the dengue vector aedes aegypti. applications of a combination of a larvicide (bacillus thuringiensis israelensis [b.t.i.]) and an adulticide (permethrin) were made using a truck-mounted forced-air generator (scorpion 20) and evaluated in the dominican republic. this method has the potential to simultaneously control adults and larvae. in bioassay cages placed in household water containers at the time of application ...19947807084
zwittermicin a-producing strains of bacillus cereus from diverse soils.bacillus cereus uw85 produces a novel aminopolyol antibiotic, zwittermicin a, that contributes to the ability of uw85 to suppress damping-off of alfalfa caused by phytophthora medicaginis. uw85 produces a second antibiotic, provisionally designated antibiotic b, which also contributes to suppression of damping-off but has not been structurally defined yet and is less potent than zwittermicin a. the purpose of this study was to isolate genetically diverse strains of b. cereus that produce zwitter ...19947811080
is231 and other bacillus thuringiensis transposable elements: a review.bacillus thuringiensis is an entomopathogenic bacterium whose toxicity is due to the presence in the sporangia of delta-endotoxin crystals active against agricultural pests and vectors of human and animal diseases. most of the genes coding for these toxin proteins are plasmid-borne and are generally structurally associated with insertion sequences (is231, is232, is240, isbt1 and isbt2) and transposons (tn4430 and tn5401). several of these mobile elements have been shown to be active and are beli ...19947813910
is231a insertion specificity: consensus sequence and dna bending at the target site.in its natural host, bacillus thuringiensis, the insertion sequence is231a is preferentially inserted into the terminal inverted repeats of the transposon tn4430. using a novel transposition assay, we demonstrate that the tn4430 ends behave as insertion hot spots for is231a in escherichia coli. sequence analysis reveals that is231a insertion sites match the 5'-ggg(n)5ccc-3' consensus. however, this consensus is not the only determinant of is231a insertion specificity. although both tn4430 ends h ...19947830551
elucidation of the mechanism of cryiiia overproduction in a mutagenized strain of bacillus thuringiensis var. tenebrionis.nb176 is a bacillus thuringiensis mutant derived by gamma-irradiation of nb125 bacillus thuringiensis var. tenebrionis (krieg). it exhibits two interesting phenotypes: (i) oligosporogeny and (ii) twofold to threefold overproduction of the cryiiia protein. southern profiles of the nb176 strain showed an additional copy(s) of the cryiiia gene located on a 4 kb hindiii fragment, in addition to the expected cryiiia gene on a 3 kb hindiii fragment. each cryiiia gene-bearing hindiii fragment was clone ...19947830581
production of multiple delta-endotoxins by bacillus thuringiensis: delta-endotoxins produced by strains of the subspecies galleriae and wuhanensis.a method was developed to assess the number of delta-endotoxins contained in bacillus thuringiensis entomocidal crystals. it utilized proteolytic conversion of 130-kda protoxin into 60- to 65-kda "true" toxin via limited proteolysis with trypsin and separation of stable n-terminal domains by fast-performance liquid chromatography. immunodiffusion experiments and n-terminal sequence determination (applied to the major component isolated by sds-page) completed the analysis of the crystal protein c ...19947704829
evaluation of granular corncob formulations of bacillus thuringiensis serovar israelensis against mosquito larvae using a semi-field bioassay method.a semi-field bioassay method using commonly available laundry tubs evaluated efficacy and residual activity of 6 granular corncob formulations of bacillus thuringiensis serovar israelensis against laboratory-reared late 3rd- and early 4th-instar larvae of aedes taeniorhynchus introduced to the tubs. these formulations produced appreciable larval mortalities (up to 75%) for 9 days posttreatment, with indications of having more prolonged activity. the consistent posttreatment larval mortality tren ...19947707052
protocol for the introduction of new bacillus thuringiensis israelensis products into the routine mosquito control program in germany.the efficacy of new and frequently used formulations of bacillus thuringiensis israelensis (b.t.i.) has been evaluated in the laboratory and in the field conditions under which they will be used in germany. the principles governing the successful introduction of new formulations of microbial control agents into routine programs have been highlighted. the potency of the formulations in use (teknar, bactimos, and vectobac) and their efficacy against the indigenous mosquito species aedes vexans, ae ...19947707059
comparative toxicity of certain mosquitocidal compounds to larvivorous fish, poecilia reticulata.toxicity of certain mosquitocidal compounds (both larvicides and adulticides) to the larvivorous fish poecilia reticulata was determined in the laboratory. among the various chemical insecticides tested, the synthetic pyrethroid deltamethrin was most toxic to fish (lc50 = 0.016 ppm), while the organophosphorus insecticide abate was least toxic (lc50 = 34 ppm). the bioinsecticides spherix (bacillus sphaericus) and bactoculicide (bacillus thuringiensis h-14) showed highest safety for the fish (lc5 ...19947713258
specificity domain localization of bacillus thuringiensis insecticidal toxins is highly dependent on the bioassay system.the bacillus thuringiensis cryla(a) and cryla(c) gene specificity regions were probed by creating and testing hybrid toxins both in vivo and in vitro against cultured insect cells or dissociated midgut epithelial cells. toxin threshold dose determinations revealed that cryla(c) is highly active against cultured choristoneura fumiferana cells (cf-1) whereas cryla(a) is nontoxic. in live insect bioassays, a reversed order of toxicity was observed. hybrid analysis revealed that the cryla(c) toxicit ...19947715447
tn5401, a new class ii transposable element from bacillus thuringiensis.a new class ii (tn3-like) transposable element, designated tn5401, was recovered from a sporulation-deficient variant of bacillus thuringiensis subsp. morrisoni eg2158 following its insertion into a recombinant plasmid. sequence analysis of the insert revealed a 4,837-bp transposon with two large open reading frames, in the same orientation, encoding proteins of 36 kda (306 residues) and 116 kda (1,005 residues) and 53-bp terminal inverted repeats. the deduced amino acid sequence for the 36-kda ...19947514590
control of aedes albopictus larvae using time-release larvicide formulations in louisiana.the ability of time-release formulations of larvicides and insect growth regulators (igrs) to provide long-term control of aedes albopictus was investigated in the field. larvicides used in the study were bactimos pellets (bacillus thuringiensis var. israelensis, active ingredient) and abate pellets (temephos, active ingredient). the igr altosid (methoprene, active ingredient) was used in pellet and sand formulations. application rates were higher than label recommendations. in a preliminary tes ...19947516963
Refresh
firstprev
...11121314151617181920...
nextlast
Displaying items 1401 - 1500 of 7316