Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
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| environmental distribution and diversity of bacillus thuringiensis in spain. | bacillus thuringiensis was isolated from 301 out of 1,005 samples collected in spain from agricultural and non-cultivated soils, dust from stored products, and dead insects. based on the production of parasporal crystals, 1,401 isolates were identified as b. thuringiensis after examining 11,982 b. thuringiensis-like colonies. we found a greater presence of b. thuringiensis in dust from grain storages than in other habitats. sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the spore-c ... | 1998 | 9741114 |
| a novel isolate of bacillus thuringiensis serovar leesis that specifically exhibits larvicidal activity against the moth-fly, telmatoscopus albipunctatus. | a soil isolate designated 88-ko-14-45, belonging to bacillus thuringiensis serovar leesis (h33), exhibited larvicidal activity against the moth-fly, telmatoscopus albipunctatus (diptera: psychodidae), but not for larvae of the culicine and aedine mosquitoes and lepidoptera. purified parasporal inclusions had an lc50 value of 5.78 micrograms/ml for the larval moth-fly, but gave no mortality against larvae of culex pipiens molestus (diptera: culicidae) at protein concentrations up to 10 mg/ml. ele ... | 1998 | 9741119 |
| [screening and rapid identification of bacillus thuringiensis mutants]. | mutants of bacillus thuringiensis subsp. kurstaki ntu 9 and bt 158, which were isolated previously for using the diamondback moth as a target insect in taiwan, were screening by either protein electrophoresis of intracellular proteins or enzyme-linked immunosorbent assay (elisa). the optimal conditions of effective protein electrophoresis were (1) 24-hour cells harvested from nutrient broth were crashed by petite glass beads followed by centrifugation. and (2) the supernatant pretreated by heati ... | 1994 | 9747349 |
| [variability of pericentromeric chromatin in chromosome 2 of ovarian nurse cells during inbreeding in anopheles atroparvus v.tiel]. | we investigated the variability of pericentromeric chromatin of chromosome 2 in ovarian nurse cells (trophocytes) in two laboratory lines of malaria mosquito anopheles atroparvus v. tiel and in their hybrids. one line had been raised by means of sib inbreeding, the other kept at constantly high population density. the inbreeding was shown to result in an increased percentage of chromosomes bearing an achromatinic zone in the centromeric region, which resulted in chromosome breakage. toxicologica ... | 1998 | 9749341 |
| development of bacillus thuringiensis fermentation and process control from a practical perspective. | bacillus thuringiensis (bt) is the most widely used biopesticide producer in the biological control market. it is very critical for the bt pesticide industry to be able to achieve a high yield in the bt fermentation process in order to reduce its cost and compete with chemical pesticides in the market. we review the overall development of bt fermentation process research and provide our point of view for the future research opportunities and potential improvements. this minireview covers the are ... | 1998 | 9756461 |
| the introduction into bacillus sphaericus of the bacillus thuringiensis subsp. medellin cyt1ab1 gene results in higher susceptibility of resistant mosquito larva populations to b. sphaericus. | the fragment containing the gene encoding the cytolytic cyt1ab1 protein from bacillus thuringiensis subsp. medellin and its flanking sequences (i. thiery, a. delécluse, m. c. tamayo, and s. orduz, appl. environ. microbiol. 63:468-473, 1997) was introduced into bacillus sphaericus toxic strains 2362, 2297, and iab872 by electroporation with the shuttle vector pmk3. only small amounts of the protein were produced in recombinant strains 2362 and iab872. the protein was detected in these strains onl ... | 1998 | 9758818 |
| optimization of cry3a yields in bacillus thuringiensis by use of sporulation-dependent promoters in combination with the stab-sd mrna sequence. | the insecticidal activity of bacillus thuringiensis strains toxic to coleopterous insects is due to cry3 proteins assembled into small rectangular crystals. toxin synthesis in these strains is dependent primarily upon a promoter that is active in the stationary phase and a stab-sd sequence that stabilizes the cry3 transcript-ribosome complex. here we show that significantly higher yields of cry3a can be obtained by using dual sporulation-dependent cyt1aa promoters to drive the expression of cry3 ... | 1998 | 9758822 |
| activities of bacillus thuringiensis insecticidal crystal proteins cyt1aa and cyt2aa against three species of sheep blowfly. | the toxicity of bacillus thuringiensis cyt1aa protein to sheep blowfly larvae depends on its solubilization and proteolytic activation. cyt1aa crystals were not toxic. full-length and trypsin-digested cyt1aa proteins were toxic to larvae of three species of sheep blowfly. neither full-length nor trypsin-digested cyt2a soluble crystal proteins were toxic. | 1998 | 9758842 |
| batch fermentation and optimization of media for bacillus thuringiensis. | the composition of no. ii medium obtained with shaking cultivation contained three factors: nitrogen source, carbon source, and inorganic salts. the relationship between component factors (x(i)) of the media and spore numbers (y) of bacillus thuringiensis (bt) was demonstrated by the orthogonal-rotation-combination test. a response surface equation was formed as follows: y = 384 - 7.245x1 + 11.705x2 + 15.475x3 + 14.039x1(2) + 41.831x2(2) - 79.49x3(2) - 35.375x1x2 - 3.375x1x3 - 106.625x2x3. the r ... | 1998 | 9759545 |
| a new pcr-based approach to a fast search of a wide spectrum of cry genes from bacillus thuringiensis strains. | a pair of highly degenerated primers was adapted to carry out a single-step pcr-detection of any known and probably unknown cry genes of classes cry1, cry4 and cry9 encoding for 130 kda protein delta-endotoxins in the natural bacillus thuringiensis (bt) strains. the southern hybridization of the product has demonstrated that essentially remote cry-genes like cry1aa and cry9a (cryig) could be represented in the single amplificate if they are simultaneously present in the genome of the analyzed st ... | 1998 | 9762424 |
| the structure and organization within the membrane of the helices composing the pore-forming domain of bacillus thuringiensis delta-endotoxin are consistent with an "umbrella-like" structure of the pore. | the aim of this study was to elucidate the mechanism of membrane insertion and the structural organization of pores formed by bacillus thuringiensis delta-endotoxin. we determined the relative affinities for membranes of peptides corresponding to the seven helices that compose the toxin pore-forming domain, their modes of membrane interaction, their structures within membranes, and their orientations relative to the membrane normal. in addition, we used resonance energy transfer measurements of ... | 1998 | 9770479 |
| sequence of the cry11bb11 gene from bacillus thuringiensis subsp. medellin and toxicity analysis of its encoded protein. | the nucleotide sequence of the cry11bb1 gene from bacillus thuringiensis subsp. medellin was determined. the corresponding protein has a deduced molecular mass of 88.2 kda, and is 60.9% and 83% identical to the proteins cry11aa1 and cry11ba1, respectively. the cry11bb1 protein contains five repetitive blocks of 16 amino acids at the c terminal part. it is highly toxic to first instar laboratory reared aedes aegypti, anopheles albimanus and culex quinquefasciatus larvae. | 1998 | 9774743 |
| expression of chromosomally inserted bacillus thuringiensis israelensis toxin genes in bacillus sphaericus | bacillus thuringiensis israelensis delta-endotoxin genes were inserted into transposon tn917 in plasmid ptv51ts and cloned into the chromosome of bacillus sphaericus 2362. many of the transformants reacted with antibody to the 135-, 128-, 65-, and 28-kda b.t.israelensis toxin proteins and were approximately 10 times more toxic to a. aegypti larvae than the untransformed host. some of the transformants differed physiologically and morphologically from the wild-type b. sphaericus. the toxicity of ... | 1998 | 9784342 |
| effects of bacillus thuringiensis and destruxins (metarhizium anisopliae mycotoxins) combinations on spruce budworm (lepidoptera: tortricidae) | laboratory bioassays were performed in order to assess the efficacy of a combination of a commercial preparation of bacillus thuringiensis var. kurstaki (b.t.k.) (thuricide) with destruxins (metarhizium anisopliae mycotoxins) on the fifth instar of choristoneura fumiferana clemens. lethal doses were determined for each microbial agent and used as a basis for the bioassays involving a combination of the two agents. interaction or the lack of interaction was determined by comparing the observed an ... | 1998 | 9784349 |
| efficacy of lepidopteran specific delta-endotoxins of bacillus thuringiensis against helicoverpa armigera | 1998 | 9784360 | |
| purification and partial amino acid sequences of the binding protein from bombyx mori for cryiaa delta-endotoxin of bacillus thuringiensis. | the binding protein for bacillus thuringiensis delta-endotoxin, cryiaa, from the brush border membrane of the midgut of bombyx mori was purified by the dot blot method and delta-endotoxin affinity chromatography. the binding protein was purified to 235-fold enrichment from cholic acid extracts of brush border membranes from b. mori midgut by activated cryiaa-affinity chromatography and deae ion-exchange chromatography. the purified binding protein showed a single band of 180 kda by sodium dodecy ... | 1998 | 9787789 |
| influence of ph on the toxicity and survival of total cells and spores of bacillus thuringiensis. | b. thuringiensis (bt) is one of the most important microorganism among those studied because of their entomopathogenic potential against insect plagues and vectors. in this work, the pathogenicity and survival of total cells and spores of three autochthonous strains of b. thuringiensis isolated from argentine soils (a61, a27 and a68) and the commercial strain hd-1 were studied at different ion hidrogen concentrations (ph = 4.4; 5.4; 7.4; 8.4; 9.4 and 10.4) under laboratory conditions. the greate ... | 1998 | 9793141 |
| variable cross-resistance to cry11b from bacillus thuringiensis subsp. jegathesan in culex quinquefasciatus (diptera: culicidae) resistant to single or multiple toxins of bacillus thuringiensis subsp. israelensis. | a novel mosquitocidal bacterium, bacillus thuringiensis subsp. jegathesan, and one of its toxins, cry11b, in a recombinant b. thuringiensis strain were evaluated for cross-resistance with strains of the mosquito culex quinquefasciatus that are resistant to single and multiple toxins of bacillus thuringiensis subsp. israelensis. the levels of cross-resistance (resistance ratios [rr]) at concentrations which caused 95% mortality (lc95) between b. thuringiensis subsp. jegathesan and the different b ... | 1998 | 9797262 |
| cyt1aa protein of bacillus thuringiensis is toxic to the cottonwood leaf beetle, chrysomela scripta, and suppresses high levels of resistance to cry3aa | the insecticidal activity of bacillus thuringiensis is due primarily to cry and cyt proteins. cry proteins are typically toxic to lepidopterous, coleopterous, or dipterous insects, whereas the known toxicity of cyt proteins is limited to dipterans. we report here that a cyt protein, cyt1aa, is also highly toxic to the cottonwood leaf beetle, chrysomela scripta, with a median lethal concentration of 2.5 ng/mm2 of leaf surface for second-instar larvae. additionally, we show that cyt1aa suppresses ... | 1998 | 9797292 |
| suppression of diamondback moth (lepidoptera: plutellidae) with an entomopathogenic nematode (rhabditida: steinernematidae) and bacillus thuringiensis berliner. | we tested the efficacy of the all strain of steinernema carpocapsae (weiser) against larvae of the diamondback moth, plutella xylostella (l.). in laboratory bioassays we found that (1) commercially formulated nematodes produced in vitro were as effective as nematodes produced in vivo, (2) resistance of p. xylostella to bacillus thuringiensis berliner subsp. kurstaki did not confer cross-resistance to nematodes, (3) mortality caused by nematodes was higher for early than late 3rd-instar p. xylost ... | 1998 | 9805498 |
| assignment of delta-endotoxin genes of the four lepidoptera-specific bacillus thuringiensis strains that produce spherical parasporal inclusions. | unique strains of bacillus thuringiensis, that belong to the four h serogroups (serovar sumiyoshiensis, serovar fukuokaensis, serovar darmstadiensis, and serovar japonensis) and produce spherical parasporal inclusions specifically toxic to lepidopteran larvae, were examined for comparative analysis of the genes encoding delta-endotoxin proteins. gene analysis revealed that there is no difference between the four strains in nucleotide sequences of the 1, 937-bp dna segment covering the four conse ... | 1998 | 9806979 |
| potency of products based on bacillus thuringiensis var. israelensis: interlaboratory variations. | six quality-control laboratories in 4 countries independently bioassayed aliquots of a flowable formulation of bacillus thuringiensis var. israelensis (b.t.i.) against the international standard powder ips-82. all laboratories substantially followed world health organization or u.s. department of agriculture standard protocols. significant differences were found in resulting potency values between laboratories. factors that may have influenced results, such as age, stage, and strain of larvae us ... | 1998 | 9813828 |
| nonessential activation and competitive inhibition of bacterial phosphatidylinositol-specific phospholipase c by short-chain phospholipids and analogues. | phosphatidylinositol-specific phospholipase c (pi-plc) from bacillus thuringiensis is an allosteric enzyme with both a phospholipid activator site and an active site. the activation of pi-plc enzyme is optimal with phosphatidylcholine (pc) binding to the activator site and anchoring the enzyme to the interface [zhou, c., et al. (1997) biochemistry 36, 347-355; zhou, c., et al. (1997) biochemistry 36, 10089-10091]. in contrast to pc, anionic short-chain phospholipids with smaller headgroups [phos ... | 1998 | 9819236 |
| the poultry red mite dermanyssus gallinae (de geer, 1778): current situation and future prospects for control. | the current importance of dermanyssus gallinae, mainly in egg layer, in europe is pointed out. the limits of conventional control methods are underlined (development of mite resistance--future insecticide legislation and animal welfare legislation). alternative control methods such as feeding deterrents or biological control, are reviewed in the context of poultry pest management. | 1998 | 9823064 |
| modulation of cry iv a toxin protein expression by glucose in bacillus thuringiensis israelensis. | bacillus thuringiensis subsp. israelensis (bti) produces cry iv a protoxin protein as part of the insecticidal crystal toxin during sporulation. this study was conducted with the objective of identifying environmental signals which regulate toxin synthesis by bti. glucose was found to repress cry iv a toxin induction at the mrna level. the repressive effect of glucose was dependent on a phosphorylation step since protein kinase inhibitor calphostin c relieved the 130-kd protoxin synthesis at bot ... | 1998 | 9826542 |
| bacillus weihenstephanensis sp. nov. is a new psychrotolerant species of the bacillus cereus group. | the bacillus cereus group comprises the four valid species bacillus cereus, bacillus mycoides, bacillus thuringiensis and bacillus anthracis. some isolates of b. cereus are known to be psychrotolerant (growth at 7 degrees c or below). here, specific sequence differences are described between the 16s rdna, the 23s rdna, the 16s-23s rdna spacer region and the genes of the major cold-shock protein homologue cspa in a variety of psychrotolerant and mesophilic b. cereus and b. mycoides strains. rando ... | 1998 | 9828439 |
| learning from past experience. | 1998 | 9831013 | |
| effect of canavanine from alfalfa seeds on the population biology of bacillus cereus | bacillus cereus uw85 suppresses diseases of alfalfa seedlings, although alfalfa seed exudate inhibits the growth of uw85 in culture (j. l. milner, s. j. raffel, b. j. lethbridge, and j. handelsman, appl. microbiol. biotechnol. 43:685-691, 1995). in this study, we determined the chemical basis for and biological role of the inhibitory activity. all of the alfalfa germ plasm tested included seeds that released inhibitory material. we purified the inhibitory material from one alfalfa cultivar and i ... | 1998 | 9835549 |
| a holistic approach for determining the entomopathogenic potential of bacillus thuringiensis strains. | the cry gene content of bacillus thuringiensis subsp. aizawai hd-133 was analyzed by a combination of high-pressure liquid chromatography (hplc) and exclusive pcr. a total of six cry genes were detected in genomic dna purified from hd-133, four from the cry1 family (cry1aa, cry1ab, cry1c, and cry1d) as well as a gene each from the cry2 (cry2b) and the cry1i families. to directly determine which genes were expressed and crystallized in the purified parasporal inclusions, solubilized and trypsiniz ... | 1998 | 9835562 |
| characterization of cry genes in a mexican bacillus thuringiensis strain collection. | mexico is located in a transition zone between the nearctic and neotropical biogeographical regions and contains a rich and unique biodiversity. a total of 496 bacillus thuringiensis strains were isolated from 503 soil samples collected from the five macroregions of the country. the characterization of the strain collection provided useful information on the ecological patterns of distribution of b. thuringiensis and opportunities for the selection of strains to develop novel bioinsecticidal pro ... | 1998 | 9835590 |
| conjugation in gram-positive bacteria and kinetics of plasmid transfer. | 1998 | 9850682 | |
| similarity in moth-fly specific larvicidal activity between two serologically unrelated bacillus thuringiensis strains. | parasporal inclusions of a bacillus thuringiensis isolate designated 92-ku-105-9 (h14/19) exhibited unusual larvicidal activity, specific for the moth-fly, telmatoscopus albipunctatus (diptera: psychodidae), similar to that of a previously reported b. thuringiensis serovar leesis (h33) strain. the lc50 value of the purified inclusions was 4.92 micrograms ml-1 for the moth-fly larvae, while no mortality was shown in the mosquitoes culex pipiens molestus and anopheles stephensi, at protein concent ... | 1998 | 9868764 |
| isolation and characterization of brush border membrane vesicles from whole aedes aegypti larvae. | studies of the binding interactions of dipteran-specific bacillus thuringiensis delta-endotoxins are hindered by the lengthy midgut dissection procedure needed for preparation of brush border membrane vesicles. in an attempt to resolve this problem, brush border membrane vesicles were isolated from homogenates of whole aedes aegypti larvae by a modification of the method of macintosh et al. (1994). these preparations were found to resolve well on sds-page and appeared as spherical vesicles of va ... | 1999 | 9878289 |
| toxicity and receptor binding properties of a bacillus thuringiensis cryic toxin active against both lepidoptera and diptera. | this study describes an investigation into the relationship among toxicity, specificity, and binding of cryic delta-endotoxin from bacillus thuringiensis subspecies aizawai hd-229. in vivo bioassays of larvae using inclusions (aedes aegypti) or solubilized toxin (spodoptera littoralis, spodoptera exigua, spodoptera frugiperda, and manduca sexta) revealed that cryic was toxic to both dipteran and lepidopteran larvae. in vitro saturation binding assays with cryic toxin labeled in vivo with [35s]me ... | 1999 | 9878290 |
| effectiveness of control measures against mosquitoes at a constructed wetland in southern california. | the effectiveness of larvicide and adulticide treatments against mosquitoes at a constructed wetland in san jacinto, california was assessed with larval surveys, trapping of emerging adults, and collections of host-seeking females by carbon dioxide-baited traps. bacillus thuringiensis var. israelensis (bti, bactimos pellets) applied at a rate of 19 kg/ha did not demonstrably affect culex larval and emergent adult populations. larval populations in the seven marshes of the wetland decreased from ... | 1998 | 9879071 |
| structure of the glycosylphosphatidylinositol-anchor of the trans-sialidase from trypanosoma cruzi metacyclic trypomastigote forms. | both, culture-derived and metacyclic trypomastigotes of trypanosoma cruzi shed a glycoprotein, the shed acute phase antigen, that is responsible for the trans-sialidase activity. in the present work the structure of the glycosylphosphatidylinositol membrane anchor of the trans-sialidase isolated from metacyclic forms was determined. parasites were metabolically labelled with [9, 10(n)3h]-palmitic acid and the glycoprotein was purified by immunoprecipitation with a monoclonal antibody directed ag ... | 1998 | 9879892 |
| cyta protein, a delta-endotoxin of bacillus thuringiensis subsp. israelensis is associated with dna. | cyta protein (27 kda) is produced by bacillus thuringiensis subsp. israelensis (bti) and is contained in its inclusion bodies. we previously reported the isolation of 25 kda portion of cyta protein (p25-cyta protein) and its strong cytotoxic activity to mammalian cells. when p25-cyta protein was applied to an anion-exchange column for further purification, three fractions (m1, m2 and m3) were separated. m1 and m2 fractions were both shown to be 25 kda protein, while m3 was a high molecular weigh ... | 1998 | 9881635 |
| spruce budworm elastase precipitates bacillus thuringiensis delta-endotoxin by specifically recognizing the c-terminal region. | a gut juice protein from choristoneura fumiferana (spruce budworm) larvae that precipitates certain delta-endotoxins shows a unique specificity for the c-terminal amino acid sequence. using homolog scanning mutants, we have identified a contiguous region of the cry1aa toxin which interacts with the 75-kda toxin precipitating protein (tpp-75)' resulting in precipitation. the contiguous region from cry1aa can be transferred to cry1ac and results in an identical precipitation reaction. the precipit ... | 1998 | 9887517 |
| introduction and expression of the cry1ac gene of bacillus thuringiensis in a cereal-associated bacterium, bacillus polymyxa. | the abilities of bacillus polymyxa and bacillus thuringiensis to survive on the rice phyllospere were compared; it was found that b. polymyxa colonizes the crop better. this study also showed that b. polymyxa inoculation to rice plants increased the shoot and the root growth of the crop. efforts were made to introduce the cry1ac gene of b. thuringiensis subsp. kurstaki into b. polymyxa so that the application of such transgenic b. polymyxa strains would prove to be dually beneficial to rice crop ... | 1999 | 9922467 |
| toxicity, binding, and permeability analyses of four bacillus thuringiensis cry1 delta-endotoxins using brush border membrane vesicles of spodoptera exigua and spodoptera frugiperda. | the binding and pore formation properties of four bacillus thuringiensis cry1 toxins were analyzed by using brush border membrane vesicles from spodoptera exigua and spodoptera frugiperda, and the results were compared to the results of toxicity bioassays. cry1fa was highly toxic and cry1ac was nontoxic to s. exigua and s. frugiperda larvae, while cry1ca was highly toxic to s. exigua and weakly toxic to s. frugiperda. in contrast, cry1bb was active against s. frugiperda but only marginally activ ... | 1999 | 9925568 |
| biochemical characterization of bacillus thuringiensis cytolytic toxins in association with a phospholipid bilayer. | the interaction of two bacillus thuringiensis cytolytic toxins, cyta and cytb, with a phospholipid bilayer and their structure in the membrane-bound state were investigated by proteolysis using phospholipid vesicles as a model system. a toxin conformational change upon membrane binding was detected by comparing the proteolytic profile of membrane-bound toxin and saline-solubilized toxin. when membrane-bound toxin was exposed to protease k or trypsin, novel cleavage sites were found between the a ... | 1999 | 9931315 |
| cdna cloning and expression of bacillus thuringiensis cry1aa toxin binding 120 kda aminopeptidase n from bombyx mori. | bacillus thuringiensis cry1aa toxin binds to a 120 kda putative receptor protein in the bombyx mori midgut. recently, this protein was purified and identified as glycosyl-phosphatidylinositol (gpi) anchored aminopeptidase n (apn). in this study, a full-length cdna thought to encode this 120 kda apn was isolated and sequenced. it has a 2958 bp orf encoding 986 amino acids. in the deduced amino acid sequence, we identified gpi-anchor and zinc-metallopeptidase signals, which are the same as those o ... | 1999 | 9931470 |
| the oligomeric state of bacillus thuringiensis cry toxins in solution. | the molecular mass of different cry toxins produced by bacillus thuringiensis bacteria was estimated by size-exclusion chromatography and non-denaturing polyacrylamide gel electrophoresis at neutral and alkaline ph in order to assess the existence of oligomers in solution. we found that cry1aa, cry1ac, cry1c, cry1d and cry3a toxins exist in solution as a mixture of monomer and high molecular mass aggregates with an apparent molecular mass greater than 600 kda, that depend on the time elapsed bet ... | 1999 | 9989219 |
| myths, models and mitigation of resistance to pesticides. | resistance to pesticides in arthropod pests is a significant economic, ecological and public health problem. although extensive research has been conducted on diverse aspects of pesticide resistance and we have learned a great deal during the past 50 years, to some degree the discussion about 'resistance management' has been based on 'myths'. one myth involves the belief that we can manage resistance. i will maintain that we can only attempt to mitigate resistance because resistance is a natural ... | 1998 | 10021775 |
| domain iii of the bacillus thuringiensis delta-endotoxin cry1ac is involved in binding to manduca sexta brush border membranes and to its purified aminopeptidase n. | three types of binding assays were used to study the binding of bacillus thuringiensis delta-endotoxin cry1ac to brush border membrane vesicle (bbmv) membranes and a purified putative receptor of the target insect manduca sexta. using hybrid proteins consisting of cry1ac and the related cry1c protein, it was shown that domain iii of cry1ac is involved in specificity of binding as observed by all three techniques. in ligand blotting experiments using sds-page-separated bbmv proteins as well as th ... | 1999 | 10027964 |
| evaluation of transgenic sweet corn hybrids expressing cryia (b) toxin for resistance to corn earworm and fall armyworm (lepidoptera: noctuidae). | many of the lepidopterous insects which attack sweet corn, zea mays l., are susceptible to insecticidal proteins produced by bacillus thuringiensis ssp. kurstaki (berliner) (btk). transgenic sweet corn expressing a synthetic cry gene for production of a btk-insecticidal protein may provide a more environmentally acceptable means of sweet corn production. eight transgenic sweet corn hybrids containing a synthetic gene for cryia(b) protein production (bt11 event) were evaluated for resistance to t ... | 1999 | 10036986 |
| a randomly amplified polymorphic dna marker specific for the bacillus cereus group is diagnostic for bacillus anthracis. | aiming to develop a dna marker specific for bacillus anthracis and able to discriminate this species from bacillus cereus, bacillus thuringiensis, and bacillus mycoides, we applied the randomly amplified polymorphic dna (rapd) fingerprinting technique to a collection of 101 strains of the genus bacillus, including 61 strains of the b. cereus group. an 838-bp rapd marker (sg-850) specific for b. cereus, b. thuringiensis, b. anthracis, and b. mycoides was identified. this fragment included a putat ... | 1999 | 10049896 |
| overexpression of the bacillus thuringiensis (bt) cry2aa2 protein in chloroplasts confers resistance to plants against susceptible and bt-resistant insects. | evolving levels of resistance in insects to the bioinsecticide bacillus thuringiensis (bt) can be dramatically reduced through the genetic engineering of chloroplasts in plants. when transgenic tobacco leaves expressing cry2aa2 protoxin in chloroplasts were fed to susceptible, cry1a-resistant (20,000- to 40,000-fold) and cry2aa2-resistant (330- to 393-fold) tobacco budworm heliothis virescens, cotton bollworm helicoverpa zea, and the beet armyworm spodoptera exigua, 100% mortality was observed a ... | 1999 | 10051556 |
| us groups sue over approval of bt crops...as uk press reports come under fire. | 1999 | 10067881 | |
| characterization of the mbl determinant and cloning of the spoiiid gene from bacillus cereus atcc 10987. | to examine the transcriptional start site of the putative bacillus cereus mbl gene, we have cloned and sequenced the upstream region of the previously reported b. cereus mbl determinant, which showed sequence similarity to the mreb morphogene from escherichia coli. primer extension analysis revealed the transcriptional start site of mbl to 259 bp upstream of the putative translational start site and showed that the mbl gene was expressed at 3, 6, and 10 h of growth after inoculation. antibodies ... | 1999 | 10069858 |
| experimental formulations of bacillus sphaericus and b. thuringiensis israelensis against culex quinquefasciatus and anopheles gambiae (diptera: culicidae) in burkina faso. | efficacies of locally produced, sustained release granular formulations of bacillus sphaericus (bs) strain 2362 and b. thuringiensis israelensis (bti) were compared with commercial liquid concentrates of the same bacteria in cesspits and rain-filled puddles in ouagadougou, burkina faso. duration of control was dependent on the product, the transient nature of some sites, and the target mosquito larvae. bs granules applied at the rate of 3.0 g/m2 (30 kg/ha) reduced culex quinquefasciatus say 99% ... | 1999 | 10071494 |
| specific binding of the e2 subunit of pyruvate dehydrogenase to the upstream region of bacillus thuringiensis protoxin genes. | during sporulation, bacillus thuringiensis produces inclusions comprised of different amounts of several related protoxins, each with a unique specificity profile for insect larvae. a major class of these genes designated cry1 have virtually identical dual overlapping promoters, but the upstream sequences differ. a gel retardation assay was used to purify a potential regulatory protein which bound with different affinities to these sequences in three cry1 genes. it was identified as the e2 subun ... | 1999 | 10075684 |
| efficient expression of mosquito-larvicidal proteins in a gram-negative bacterium capable of recolonization in the guts of anopheles dirus larva. | the gram-negative bacterium, an11/2 g1, isolated from the guts of anopheles dirus mosquito larvae, was identified as enterobacter amnigenus. the e. amnigenus was able to recolonize in the gut of an. dirus larva but not in those of aedes aegypti and culex quinquefasciatus larvae. it was able to float in water for a longer period than bacillus thuringiensis subsp. israelensis and bacillus sphaericus. these are desirable characteristics for a delivery vehicle of mosquito-larvicidal toxins for the c ... | 1999 | 10077823 |
| field trials of biolarvicide bacillus thuringiensis var. israelensis strain 164 and the larvivorous fish aplocheilus blocki against anopheles stephensi for malaria control in goa, india. | severe outbreaks of malaria occurred in the coastal villages of the candolim primary health centre (phc) of goa, india, in 1993 and 1994. these outbreaks were associated with accelerated construction activity with an influx of migrant laborers. the weekly application of bacillus thuringiensis var. israelensis (b.t.i.) strain 164 at 1 g/m2 and introduction of the indigenous larvivorous fish aplocheilus blocki in major breeding habitats of anopheles stephensi replaced ongoing ddt spraying and pyre ... | 1998 | 10084141 |
| acute toxicity of selected pesticides to the pacific blue-eye, pseudomugil signifer (pisces). | because the larvivorous fish pseudomugil signifer is native to southeastern queensland and is abundant in shallow estuarine habitats, intertidal marshes, wetland habitats, and freshwater streams, it was chosen as an indicator species for toxicologic studies with pesticides. acute toxicity studies with 2 organophosphorus pesticides (pirimiphos-methyl and temephos) and 3 alternate compounds under evaluation for registration in australia (bacillus thuringiensis var. israelensis, s-methoprene, and p ... | 1998 | 10084142 |
| bacterial control of mosquito larvae: investigation of stability of bacillus thuringiensis var. israelensis and bacillus sphaericus standard powders. | bacillus thuringiensis var. israelensis and bacillus sphaericus products were assayed against their respective reference powders ips82 and sph88. since their production in 1982 and 1988, the potency and larvicidal activity of these standard powders have been regularly checked on their test insects aedes aegypti (for ips82) or culex pipiens (for sph88). over the 16-year evaluation period of ips82 and 10-year evaluation period of sph88, their potencies were considered stable. the global mean of ea ... | 1998 | 10084145 |
| isolation and detection of listeria monocytogenes using fluorogenic and chromogenic substrates for phosphatidylinositol-specific phospholipase c. | the bcm listeria monocytogenes detection system (lmds) consists of a selective preenrichment broth (lmpeb), selective enrichment broth (lmseb), selective/differential plating medium (lmpm), and identification on a confirmatory plating medium (lmcm). the efficacy of the bcm lmds was determined using pure cultures and naturally and artificially contaminated environmental sponges. the bcm lmpeb allowed the growth of listeria and resuscitation of heat-injured l. monocytogenes. the bcm lmseb, which c ... | 1999 | 10090243 |
| kinetic modeling of omega-transamination for enzymatic kinetic resolution of alpha-methylbenzylamine. | a kinetic model for omega-transaminase from bacillus thuringiensis js64 was developed by using the king-altman method to simulate the kinetic resolution of alpha-methylbenzylamine (alpha-mba). starting from a ping-pong bi-bi mechanism, a complete kinetic model including substrate inhibition only in the reverse reaction (i.e., transamination between acetophenone and l-alanine) was developed. the asymmetric synthesis of (s)-alpha-mba proved to be difficult due to a much lower maximum reverse react ... | 1998 | 10099461 |
| integrative model for binding of bacillus thuringiensis toxins in susceptible and resistant larvae of the diamondback moth (plutella xylostella). | insecticidal crystal proteins from bacillus thuringiensis in sprays and transgenic crops are extremely useful for environmentally sound pest management, but their long-term efficacy is threatened by evolution of resistance by target pests. the diamondback moth (plutella xylostella) is the first insect to evolve resistance to b. thuringiensis in open-field populations. the only known mechanism of resistance to b. thuringiensis in the diamondback moth is reduced binding of toxin to midgut binding ... | 1999 | 10103230 |
| cloning and nucleotide sequence analysis of gyrb of bacillus cereus, b. thuringiensis, b. mycoides, and b. anthracis and their application to the detection of b. cereus in rice. | as 16s rrna sequence analysis has proven inadequate for the differentiation of bacillus cereus from closely related species, we employed the gyrase b gene (gyrb) as a molecular diagnostic marker. the gyrb genes of b. cereus jcm 2152(t), bacillus thuringiensis iam 12077(t), bacillus mycoides atcc 6462(t), and bacillus anthracis pasteur #2h were cloned and sequenced. oligonucleotide pcr primer sets were designed from within gyrb sequences of the respective bacteria for the specific amplification a ... | 1999 | 10103241 |
| transition state of the rate-limiting step of heat denaturation of cry3a delta-endotoxin. | heat denaturation of cry3a delta-endotoxin from bacillus thuringiensis var. tenebrionis and its 55 kda fragment was studied by differential scanning microcalorimetry at low ph. analysis of the calorimetric data has shown that denaturation of cry3a delta-endotoxin is a nonequilibrium process at heating rates from 0. 125 to 2 k/min. this means that the stability of delta-endotoxin (the apparent temperature of denaturation tm) under these conditions is under kinetic control rather than under thermo ... | 1999 | 10194327 |
| expression of delta-endotoxin cryia(c) gene of bacillus thuringiensis in escherichia coli and streptomyces lividans. | the cryia(c) gene of bacillus thuringiensis was isolated from plasmid pos1000. in order to obtain a proper cloning site and open reading frame, some dna sequences preceding the initiating codon of the gene were replaced by synthetic oligonucleotide sequences. the isolated cryia(c) was cloned into e. coli expression vector pkk223-3, and production of cryia(c) protein was detected after induction by iptg. a recombinant plasmid, phz1256, was constructed by insertion of the cryia(c) gene into strept ... | 1998 | 10196629 |
| unique activity associated with non-insecticidal bacillus thuringiensis parasporal inclusions: in vitro cell-killing action on human cancer cells. | parasporal inclusion proteins from a total of 1744 bacillus thuringiensis strains, consisting of 1700 japanese isolates and 44 reference type strains of existing h serovars, were screened for cytocidal activity against human leukaemia t cells and haemolytic activity against sheep erythrocytes. of 1684 b. thuringiensis strains having no haemolytic activity, 42 exhibited in vitro cytotoxicity against leukaemia t cells. these non-haemolytic but leukaemia cell-toxic strains belonged to several h-ser ... | 1999 | 10196753 |
| updating the h-antigen classification of bacillus thuringiensis. | the classification of bacillus thuringiensis strains has been revised and updated based on flagellar antigens which have been in use for many years. sixty-nine serotypes and 13 sub-antigenic groups have now been identified, giving 82 serovars among the 3500 b. thuringiensis isolates of the iebc collection. the number of serovars has gradually increased with the total number of strains. the biochemical characters used have also been investigated and their value assessed for identification of b. t ... | 1999 | 10212410 |
| genome organization is not conserved between bacillus cereus and bacillus subtilis. | the opportunistic pathogen bacillus cereus is the genetically stable member of a group of closely related bacteria including the insect pathogen bacillus thuringiensis and the mammalian pathogen bacillus anthracis. physical maps of b. cereus and b. thuringiensis strains show considerable variations in discrete parts of the chromosome, suggesting that certain genome regions are more prone to rearrangements. b. cereus belongs to the same subgroup of bacillus species as bacillus subtilis, by both p ... | 1999 | 10217496 |
| n-acetylgalactosamine on the putative insect receptor aminopeptidase n is recognised by a site on the domain iii lectin-like fold of a bacillus thuringiensis insecticidal toxin. | binding of the insecticidal bacillus thuringiensis cry1ac toxin to the putative receptor aminopeptidase n is specifically inhibited by n-acetylgalactosamine (galnac), suggesting that this toxin recognises galnac on the receptor. a possible structural basis for involvement of domain iii of the toxin in carbohydrate-mediated receptor recognition was noted in the similarity between the domain iii fold of the related toxin cry3a and a carbohydrate-binding domain in the 1,4-beta-glucanase from cellul ... | 1999 | 10222207 |
| subspecies-dependent regulation of bacillus thuringiensis protoxin genes. | bacillus thuringiensis accumulates, primarily during sporulation, large quantities of insecticidal protoxins which are deposited as crystalline, intracellular inclusions. most subspecies contain several plasmid-encoded cry genes, each of which has a unique specificity. the overall toxicity profile of a subspecies depends not only on the array of cry genes present but also on the relative expression of the genes. in general, transcription depends on sporulation-specific sigma factors, but little ... | 1999 | 10223968 |
| role of bacillus thuringiensis toxin domains in toxicity and receptor binding in the diamondback moth | the toxic fragment of bacillus thuringiensis crystal proteins consists of three distinct structural domains. there is evidence that domain i is involved in pore formation and that domain ii is involved in receptor binding and specificity. it has been found that, in some cases, domain iii is also important in determining specificity. furthermore, involvement of domain iii in binding has also been reported recently. to investigate the role of toxin domains in the diamondback moth (plutella xyloste ... | 1999 | 10223976 |
| antagonism between cry1ac1 and cyt1a1 toxins of bacillus thuringiensis | most strains of the insecticidal bacterium bacillus thuringiensis have a combination of different protoxins in their parasporal crystals. some of the combinations clearly interact synergistically, like the toxins present in b. thuringiensis subsp. israelensis. in this paper we describe a novel joint activity of toxins from different strains of b. thuringiensis. in vitro bioassays in which we used pure, trypsin-activated cry1ac1 proteins from b. thuringiensis subsp. kurstaki, cyt1a1 from b. thuri ... | 1999 | 10223999 |
| toxin-mediated insect resistance in plants. | we are currently in an interesting phase of plant biotechnology releases, both for the scientists responsible for these innovations who are beginning to see their ideas realized, and for the biotechnology companies that are starting to see a return on their investment. one of the most notable examples, is the introduction of transgenic crops that are engineered to express a bacillus thuringiensis toxin that confers resistance to insect predation. however, the picture is not altogether positive - ... | 1999 | 10234264 |
| inheritance of resistance to bacillus thuringiensis toxin (dipel es) in the european corn borer | resistance in the european corn borer, ostrinia nubilalis (hubner), to a commercial formulation of bacillus thuringiensis (bt) berliner toxin, dipel es, appears to be inherited as an incompletely dominant autosomal gene. this contrasts with the inheritance of resistance to bt in other insects, where it has usually been characterized as a recessive trait. the proposed high-dose/refuge strategy for resistance management in bt maize depends on resistance being recessive or partially recessive. if f ... | 1999 | 10320377 |
| replication mechanism and sequence analysis of the replicon of paw63, a conjugative plasmid from bacillus thuringiensis. | a 5.8-kb fragment of the large conjugative plasmid paw63 from bacillus thuringiensis subsp. kurstaki hd73 containing all the information for autonomous replication was cloned and sequenced. by deletion analysis, the paw63 replicon was reduced to a 4.1-kb fragment harboring four open reading frames (orfs). rep63a (513 amino acids [aa]), encoded by the largest orf, displayed strong similarity (40% identity) to the replication proteins from plasmids pambeta1, pip501, and psm19035, indicating that t ... | 1999 | 10322022 |
| epa biotech rule reviewed yet again. | 1999 | 10331783 | |
| bacillus thuringiensis serotype h34 isolated from human and insecticidal strains serotypes 3a3b and h14 can lead to death of immunocompetent mice after pulmonary infection. | in 1995, we isolated a strain of bacillus thuringiensis serotype h34 from severe human tissue necrosis. this bacterium was able to induce myonecrosis in immunosuppressed mice after cutaneous infection. its potential pathogenicity for immunocompetent hosts was investigated in a mouse model of pulmonary infection. mice infected intranasally by a suspension containing 10(8) spores died within 8 h in a clinical toxic-shock syndrome. in the same conditions, infection with a mutant without crystalline ... | 1999 | 10340711 |
| laboratory evaluation of biotic and abiotic factors that may influence larvicidal activity of bacillus thuringiensis serovar. israelensis against two florida mosquito species. | a technical powder of bacillus thuringiensis serovar. israelensis (b.t.i.) (vectobac tp, 5,000 international toxic units [itu]/mg), an aqueous suspension (vectobac 12as, 1,200 itu/mg), and a granular formulation (vectobac cg, 200 itu/mg) were tested in the laboratory under different biotic and abiotic, conditions for efficacy against larvae of saltwater (aedes taeniorhynchus) and freshwater (culex nigripalpus) mosquitoes. second-, 3rd-, and 4th-instar larvae of cx. nigripalpus were 1.3-3-fold mo ... | 1999 | 10342266 |
| laboratory evaluation of selected larvicides and insect growth regulators against field-collected culex quinquefasciatus larvae from urban dhaka, bangladesh. | five organophosphates (ops) (chlorpyrifos, chlorpyrifos methyl, fenthion, malathion, and temephos), 3 pyrethroids (bifenthrin, cypermethrin, and permethrin), 1 phenyl pyrazole (fipronil), 2 microbial pesticides (bacillus thuringiensis serovar. israelensis [b.t.i.] and bacillus sphaericus), and 3 insect growth regulators (igrs) (diflubenzuron, methoprene, and pyriproxyfen) were evaluated against field-collected culex quinquefasciatus larvae from urban dhaka, bangladesh. the lc90 values of all ops ... | 1999 | 10342267 |
| comparison of isozyme patterns of aedes aegypti populations collected from pre- and post-bacillus thuringiensis israelensis treatment sites in thailand. | isozyme patterns of 13 field-collected populations of aedes aegypti from thailand were compared using starch gel electrophoresis. three populations were collected before the bacillus thuringiensis var. israelensis, (b.t.i.) application was initiated. the other 10 populations were collected after the b.t.i. treatment. results revealed that the number of polymorphic loci were lower in the b.t.i. treated populations as compared to controls. in addition, lower genetic variability was found in popula ... | 1999 | 10342268 |
| aggregation of bacillus thuringiensis cry1a toxins upon binding to target insect larval midgut vesicles | during sporulation, bacillus thuringiensis produces crystalline inclusions comprised of a mixture of delta-endotoxins. following ingestion by insect larvae, these inclusion proteins are solubilized, and the protoxins are converted to toxins. these bind specifically to receptors on the surfaces of midgut apical cells and are then incorporated into the membrane to form ion channels. the steps required for toxin insertion into the membrane and possible oligomerization to form a channel have been ex ... | 1999 | 10347034 |
| transgenic pollen harms monarch larvae. | 1999 | 10353241 | |
| intragastric and intraperitoneal administration of cry1ac protoxin from bacillus thuringiensis induces systemic and mucosal antibody responses in mice. | the spore-forming soil bacterium bacillus thuringiensis produces parasporal inclusion bodies composed by delta-endotoxins also known as cry proteins, whose resistance to proteolysis, stability in highly alkaline ph and innocuity to vertebrates make them an interesting candidate to carrier of relevant epitopes in vaccines. the purpose of this study was to determine the mucosal and systemic immunogenicity in mice of cry1ac protoxin from b. thuringiensis hd73. crystalline and soluble forms of the p ... | 1999 | 10353588 |
| bacillus thuringiensis cry1ac protoxin is a potent systemic and mucosal adjuvant. | recently we demonstrated that recombinant cry1ac protoxin from bacillus thuringiensis is a potent systemic and mucosal immunogen. in this study we compared the adjuvant effects of cry1ac and cholera toxin (ct) for the hepatitis b surface antigen (hbsag) and bovine serum albumin (bsa). the antibody responses of intestinal secretions and serum were determined by elisa in balb/c mice immunized through the intragastric (ig) or intraperitoneal (ip) routes. when hbsag was administered via ig, the anti ... | 1999 | 10354369 |
| association of plasmid integrative j7w-1 prophage with bacillus thuringiensis strains. | a region homologous to the genome of plasmid integrative phage j7w-1 was detected in the largest plasmid in 3 out of 22 type strains of bacillus thuringiensis, dendrolimus (den), aizawai (aiz) and indiana (ind). phage induction by ethidium bromide observed particularly in the j7w-1 lysogen was identified in den and ind but not aiz strains. the morphology of the phage induced in den and ind strains was identical to j7w-1, but the phage production in ind strain was lower as compared to the j7w-1 l ... | 1998 | 10358732 |
| trade concerns dominate gm debate in us. | 1999 | 10360556 | |
| plcr is a pleiotropic regulator of extracellular virulence factor gene expression in bacillus thuringiensis. | members of the bacillus cereus group (b. anthracis, b. cereus, b. mycoides and b. thuringiensis) are well-known pathogens of mammals (b. anthracis and b. cereus) and insects (b. thuringiensis). the specific diseases they cause depend on their capacity to produce specific virulence factors, such as the lethal toxin of b. anthracis and the cry toxins of b. thuringiensis. however, these bacillus spp. also produce a variety of proteins, such as phospholipases c, which are known to act as virulence f ... | 1999 | 10361306 |
| analysis of the requirement for a pub110 mob region during tn916-dependent mobilization. | tn916-dependent mobilization of nonconjugative plasmids pub110 and its derivative pub110deltam was compared. deleting a 787-bp fragment from the pub110 mob region created plasmid pub110deltam. deletion of the mob region of pub110 rendered the plasmid nontransferable by the conjugative plasmids of bacillus thuringiensis subsp. israelensis. during matings between bacillus subtilis (tn916) and b. thuringiensis subsp. israelensis, however, tn916-dependent mobilization of plasmids pub110 and pub110de ... | 1999 | 10366523 |
| role of phosphorylation sites and the c2 domain in regulation of cytosolic phospholipase a2. | cytosolic phospholipase a2 (cpla2) mediates agonist-induced arachidonic acid release, the first step in eicosanoid production. cpla2 is regulated by phosphorylation and by calcium, which binds to a c2 domain and induces its translocation to membrane. the functional roles of phosphorylation sites and the c2 domain of cpla2 were investigated. in sf9 insect cells expressing cpla2, okadaic acid, and the calcium-mobilizing agonists a23187 and cryic toxin induce arachidonic acid release and translocat ... | 1999 | 10366595 |
| bacillus thuringiensis insecticidal cry1aa toxin binds to a highly conserved region of aminopeptidase n in the host insect leading to its evolutionary success. | bacillus thuringiensis insecticidal protein, cry1aa toxin, binds to a specific receptor in insect midguts and has insecticidal activity. therefore, the structure of the receptor molecule is probably a key factor in determining the binding affinity of the toxin and insect susceptibility. the cdna fragment (px frg1) encoding the cry1aa toxin-binding region of an aminopeptidase n (apn) or an apn family protein from diamondback moth, plutella xylostella midgut was cloned and sequenced. a comparison ... | 1999 | 10366728 |
| time for a fresh look at the bacterial chromosome. | 1999 | 10366858 | |
| bacterial s-layers. | s-layers are produced by the self assembly of proteinaceous subunits on the surfaces of prokaryotes, so that planar, monomolecular-thick crystalline lattices are formed. some archaeal and eubacterial s-layer proteins are glycosylated. these lattices typically have center-to-center spacings of less than 25 nm, which makes them attractive for biomimetic or nanotechnological applications. | 1999 | 10366863 |
| stimulation of no synthase activity in the immune-competent lepidopteran estigmene acraea hemocyte line. | in contrast to the vertebrate immune system, nearly nothing is known about the immunological role of nitric oxide (no) in invertebrates. this study provides evidence of the presence of a no synthase (nos) activity in an immune-competent, macrophage-like insect hemocyte line, previously established from larvae of the lepidopteran insect estigmene acraea. as proven by photometric determination of nitroblue tetrazolium reduction after cell fixation, the e. acraea cells possess nadph diaphorase (nad ... | 1999 | 10369182 |
| [the influence of the 20 kda protein from bacillus thuringiensis subsp. israelensis on the cytolytic activity of cyta]. | in order to understand the influence of the 20 kda protein on the cytolytic activity of cyta protein, a set of pcr primers were designed to amplify 20 kda protein and cyta protein genes. the genes were ligated to e. coli expression vector puhe24 and transformed into e. coli xl1 and dh5 alpha. the clones, lz20, lzcyta and lz20a containing 20 kda protein gene, cyta protein gene and 20 kda-cyta genes were obtained respectively. the influence of the clones on the growth of e. coli cells was determin ... | 1999 | 10375855 |
| immune responses in farm workers after exposure to bacillus thuringiensis pesticides. | although health risks to pesticides containing bacillus thuringiensis (bt) have been minimal, the potential allergenicity of these organisms has not been evaluated. therefore, a health survey was conducted in farm workers before and after exposure to bt pesticides. farm workers who picked vegetables that required bt pesticide spraying were evaluated before the initial spraying operation (n = 48) and 1 and 4 months after (n = 32 and 20, respectively). two groups of low- (n = 44) and medium- (n = ... | 1999 | 10379004 |
| photorhabdus toxins: novel biological insecticides. | following concerns over the potential for insect resistance to insecticidal bacillus thuringiensis toxins expressed in transgenic plants, there has been recent interest in novel biological insecticides. over the past year there has been considerable progress in the cloning of several alternative toxin genes from the bacteria photorhabdus luminescens and xenorhabdus nematophilus. these genes encode large insecticidal toxin complexes with little homology to other known toxins. | 1999 | 10383860 |
| bt resistance plan appraised. | 1999 | 10385310 | |
| agricultural biotechnology. | 1999 | 10385330 | |
| expression of orf1 from the bacillus thuringiensis nrd-12 cry2aa1 operon. | the 5' untranslated region and the orf1 sequence from the cry2aa1 operon from bacillus thuringiensis subsp. kurstaki nrd-12 were sequenced and compared to that from strain hd-1. the start codon described in hd-1 does not yield in nrd-12 a protein of the expected size of 20 kda, but a 10-amino acid peptide. a second, highly conserved start codon is located 25 bp downstream from the first one and corresponds to an open reading frame of the same size in all known orf1-related sequences. expression ... | 1999 | 10387110 |
| binding of phylogenetically distant bacillus thuringiensis cry toxins to a bombyx mori aminopeptidase n suggests importance of cry toxin's conserved structure in receptor binding. | we investigated the binding proteins for three cry toxins, cry1aa, cry1ac, and the phylogenetically distant cry9da, in the midgut cell membrane of the silkworm. in a ligand blot experiment, cry1ac and cry9da bound to the same 120-kda aminopeptidase n (apn) as cry1aa. a competition experiment with the ligand blot indicated that the three toxins share the same binding site on several proteins. the values of the dissociation constants of the three cry toxins and 120-kda apn are as low as the case o ... | 1999 | 10387111 |
| impact of bacillus thuringiensis var. israelensis on larvae of chironomus thummi thummi and psectrocladius psilopterus (diptera: chironomidae) | chironomid larvae, especially species of the subfamily chironominae, are known to be sensitive to the mosquitocidal bacterium bacillus thuringiensis var. israelensis (b.t.i.). in this study, bioassays and electron microscopic investigations were carried out with third- and fourth-instar larvae of chironomus thummi thummi kieffer (subfamily chironominae) and psectrocladius psilopterus kieffer (subfamily orthocladiinae) in order to study the sensitivity of species belonging to different chironomid ... | 1999 | 10388545 |
| interaction between functional domains of bacillus thuringiensis insecticidal crystal proteins. | interactions among the three structural domains of bacillus thuringiensis cry1 toxins were investigated by functional analysis of chimeric proteins. hybrid genes were prepared by exchanging the regions coding for either domain i or domain iii among cry1ab, cry1ac, cry1c, and cry1e. the activity of the purified trypsin-activated chimeric toxins was evaluated by testing their effects on the viability and plasma membrane permeability of sf9 cells. among the parental toxins, only cry1c was active ag ... | 1999 | 10388684 |
| production of cry11a and cry11ba toxins in bacillus sphaericus confers toxicity towards aedes aegypti and resistant culex populations. | cry11a from bacillus thuringiensis subsp. israelensis and cry11ba from bacillus thuringiensis subsp. jegathesan were introduced, separately and in combination, into the chromosome of bacillus sphaericus 2297 by in vivo recombination. two loci on the b. sphaericus chromosome were chosen as target sites for recombination: the binary toxin locus and the gene encoding the 36-kda protease that may be responsible for the cleavage of the mtx protein. disruption of the protease gene did not increase the ... | 1999 | 10388698 |