Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
|---|
| feeding behavior of bollworm and tobacco budworm (lepidoptera: noctuidae) larvae in mixed stands of nontransgenic and transgenic cotton expressing an insecticidal protein. | feeding behavior of third-instar bollworm, helicoverpa zea (boddie), and tobacco budworm, heliothis virescens (f.), was observed in pure and mixed stands of nontransgenic and transgenic cotton (btk), gossypium hirsutum l., expressing an insecticidal protein cryia(c) from a bacterium, bacillus thuringiensis berliner subsp. kurstaki. five plant stands composed of btk and non-btk plants were evaluated; two pure stands and three mixed stands. percentage ratios of btk to non-btk plants in the stands ... | 2000 | 10985046 |
| plant-toxin interactions in transgenic bt cotton and their effect on mortality of helicoverpa armigera (lepidoptera: noctuidae). | in australia, transgenic cotton plants expressing the cry1ac gene from bacillus thuringiensis berliner variety kurstaki are less toxic to first-instar helicoverpa armigera (hübner) after the plant is producing fruit. we developed two bioassay methods (leaf mush, leaf disk) to test if the physiological state of the plants explained changes in toxicity and a third method (diet incorporation) was developed to quantify the toxicity of bt leaves when mixed in chickpea diet. cry1ac protein was less to ... | 2000 | 10985045 |
| late-instar european corn borer (lepidoptera: crambidae) tunneling and survival in transgenic corn hybrids. | field studies were conducted in 1996 and 1997 to determine injury by and survival of late-instar european corn borer, ostrinia nubilalis (hübner), on genetically altered bacillus thuringiensis berliner corn, zea mays l. cry1ab events 176, bt11, mon810, and mon802; cry1ac event dbt418; and cry9c event cbh351 were evaluated. plants of each corn hybrid were manually infested with two third-, fourth-, or fifth-instar o. nubilalis. larvae were held in proximity to the internode of the plant above the ... | 2000 | 10985043 |
| baseline susceptibility of the corn earworm (lepidoptera: noctuidae) to the cry1ab toxin from bacillus thuringiensis. | susceptibility to cry1ab toxin from bacillus thuringiensis (bt) was determined for 12 field populations of neonate corn earworm, helicoverpa zea (boddie), from the united states. earworm larvae were exposed to artificial diet treated with increasing bt concentrations, and mortality and growth inhibition were evaluated after 7 d. the range of variation in bt susceptibility indicated by growth inhibition was very similar to that indicated by mortality. although interpopulation variation in suscept ... | 2000 | 10985041 |
| comparative insecticidal properties of two nucleopolyhedrovirus vectors encoding a similar toxin gene chimer. | laboratory, greenhouse and field studies were conducted to characterize the insecticidal properties of genetically altered forms of autographa californica (speyer) nucleopolyhedrovirus (acnpv) and helicoverpa zea (boddie) npv (hznpv) against selected heliothine species. the altered viruses each contained a chimeric 0.8-kb fragment encoding the insect-specific, sodium channel neurotoxin from the algerian scorpion androctonus australis hector (aait, hence recombinant viruses designated ac-aait and ... | 2000 | 10985018 |
| lack of toxicity to adults of the mexican fruit fly (diptera: tephritidae) of beta-exotoxin in bacillus thuringiensis endotoxin preparations. | beta-exotoxin (thuringiensin) was found in high titers in centrifugation supernatants and acetone/lactose powders produced from centrifugation pellets of strains guat 1 and hd 2 of bacillus thuringiensis (berliner). diets containing powders of either strain were toxic, diets containing guat 1 supernatant were not toxic, diets containing hd 2 supernatant were slightly toxic, and diets containing powders or supernatants from uninoculated culturing medium spiked with beta-exotoxin were not toxic. m ... | 2000 | 10985014 |
| an in-field screen for early detection and monitoring of insect resistance to bacillus thuringiensis in transgenic crops. | we present a field-based approach to detect and monitor insects with resistance to insecticidal toxins produced by transgenic plants. our objective is to estimate the phenotypic frequency of resistance in a population by relating the densities of insects on genetically transformed plants to densities on nontransformed plants. we focus on european corn borer, ostrinia nubilalis (hübner), in sweet corn, zea mays l., expressing cry1ab from bacillus thuringiensis subsp. kurstaki berliner to illustra ... | 2000 | 10985012 |
| common occurrence of enterotoxin genes and enterotoxicity in bacillus thuringiensis. | seventy-four strains of bacillus thuringiensis thuringiensis representing 24 serovars were examined for the presence of three enterotoxin genes/operons; the non-haemolytic enterotoxin nhe, the haemolytic enterotoxin hbl and the bacillus cereus toxin bcet using polymerase chain reaction. the nhebc genes were found in all strains examined, the hblcd genes in 65 of the 74 strains and bcet in 63 strains. there was little consistency of the distribution of enterotoxin loci among strains of the same s ... | 2000 | 10981706 |
| toxicity and receptor binding properties of bacillus thuringiensis delta-endotoxins to the midgut brush border membrane vesicles of the rice leaf folders, cnaphalocrocis medinalis and marasmia patnalis. | pesticidal activity and receptor-binding properties of bacillus thuringiensis toxins to rice leaf folders, cnaphalocrocis medinalis and marasmia patnalis, were investigated. saturation and competition binding experiments were done with iodine ((125)1)-labeled bt proteins and brush border membrane vesicles prepared from the midgut of c. medinalis and m. patnalis. the results show saturable, specific, and high-affinity binding of all toxins except cry2a toxin. cry1aa and cry2a toxins were bound wi ... | 2000 | 10977896 |
| correlation of the insecticidal activity of the bacillus thuringiensis a4 strain against bactrocera oleae (diptera) with the 140-kda crystal polypeptide. | the crystals of the soil-isolated bacillus thuringiensis (bt) strain a4 consist of two polypeptides with molecular mass of 140 kda and 32 kda that exhibit insecticidal activity against adult flies of bactrocera oleae (diptera). plasmid curing applied to this strain resulted in the isolation of several subclones exhibiting alterations in their crystal polypeptides as well as two acrystalliferous subclones. the crystals of subclone 1.1 lacked the 32-kda polypeptide and consisted uniquely of a 140- ... | 2000 | 10977893 |
| comparative study of the frequency, flagellar serotype, crystal shape, toxicity, and cry gene contents of bacillus thuringiensisfrom three environments. | a number of bacillus thuringiensis isolates from sericultural farm, soil, and granary samples in korea were found. b. thuringiensis isolates were predominant in granary (40%), followed by sericultural farm (33% and 25% in the spring and fall isolation), and soil (10%). in toxicity tests for three areas, lepidopteran-active isolates were rich in the spring of sericultural farm and granary, but the fall isolation of sericultural farm displayed that a large number of b. thuringiensis isolates havin ... | 2000 | 10977891 |
| withdrawn greenpeace bt suit enters spin cycle. | 2000 | 10973201 | |
| improved shuttle vector for expression of chitinase gene in bacillus thuringiensis. | a 6.96-kbp plasmid vector pbcx was constructed from the plasmid pbc16 (4.4 kbp) and a 2.56-kbp fragment of pbluescript ii ks. the bifunctional plasmid pbcx conferred ampicillin and tetracycline resistance in escherichia coli but only tetracycline resistance in bacillus thuringiensis. it has unique sites for bamhi, smai, psti, hindiii, sali, xhoi, draii, apai and kpni derived from pbluescript ii ks and was lost at a low rate in b. thuringiensis subsp. israelensis when cultured in luria-bertani br ... | 2000 | 10972713 |
| molecular and insecticidal characterization of a bacillus thuringiensis strain isolated during a natural epizootic. | a new bacillus thuringiensis strain belonging to the serovar aizawai was isolated from a dead larva of the lepidopteran mythimna loreyi collected in a corn crop in spain during a natural epizootic. this strain, which was named leapi01, was compared with the kurstaki and aizawai strains isolated from dipel(r) and xentari(r), by electron microscopy, sds-page, plasmid pattern, pcr and insecticidal activity. this strain showed similar morphological and biochemical characteristics to the standard str ... | 2000 | 10971764 |
| [prevalence of microbiota in the digestive tract of wild females of lutzomyia longipalpis lutz & neiva, 1912) (diptera: psychodidae)]. | we dissected the digestive tract of 245 females in pools of 35 flies forming 7 groups. these flies were lutzomyia longipalpis originating from lapinha cave, lagoa santa, minas gerais. out of the 8 species of bacteria isolated there was a predominancy of gram negative bacterias (gnb) in the group of non-fermenters of sugar belonging to the following species: acinetobacter lwoffii, stenotrophomonas maltophilia, pseudomonas putida and flavimonas orizihabitans. the group of gnb fermenters were: ente ... | 2000 | 10967602 |
| development and characterization of diamondback moth resistance to transgenic broccoli expressing high levels of cry1c. | a field-collected colony of the diamondback moth, plutella xylostella, had 31-fold resistance to cry1c protoxin of bacillus thuringiensis. after 24 generations of selection with cry1c protoxin and transgenic broccoli expressing a cry1c protein, the resistance that developed was high enough that neonates of the resistant strain could complete their entire life cycle on transgenic broccoli expressing high levels of cry1c. after 26 generations of selection, the resistance ratios of this strain to c ... | 2000 | 10966391 |
| paramecium gpi proteins: variability of expression and localization. | in paramecium primaurelia, the two major classes of cell surface proteins, the surface antigen (sag) and the surface gpi proteins (sgps), are linked to the plasma membrane through a glycosylphosphatidylinositol (gpi) anchor. in the present study, we have characterized the expression of the sgps in several geographical strains of p. primaurelia and p. tetraurelia at different temperatures, 23 degrees c and 32 degrees c. the identification of the expressed sgps was performed on purified cilia, by ... | 2000 | 10965955 |
| cross-resistance to bacillus thuringiensis toxin cry1ja in a strain of diamondback moth adapted to artificial diet. | 2000 | 10963409 | |
| screening for bacillus thuringiensis crystal proteins active against the cabbage looper, trichoplusia ni. | toxicity tests were performed to find among cry1 and cry2 bacillus thuringiensis crystal proteins those with high activity against the cabbage looper. tests were performed with neonate larvae on surface-contaminated artificial diet. the crystal proteins found to be toxic were, from higher to lower toxicity: cry1ac, cry1ab, cry1c, cry2aa, cry1j, and cry1f (lc50 of 1.14.1, 3.4-4.4, 12, 34, 87, and 250 ng/cm2, respectively). cry1b, cry1d, and cry1e can be considered nontoxic (lc50 higher than 2500 ... | 2000 | 10963406 |
| activation pattern and toxicity of the cry11bb1 toxin of bacillus thuringiensis subsp. medellin. | bacillus thuringiensis protoxins undergo proteolytic processing in the midgut of susceptible insects to become active. the ability to process the cry11bb1 protoxin by trypsin and culex quinquefasciatus larval gut extracts was tested. the protease activity indicated by the appearance of proteolytic products increased with an increment in ph, with the highest activity being observed at ph 10.6. a time course study showed the proteolysis of the 94-kda cry11bb protein ending with the production of f ... | 2000 | 10963404 |
| intranasal, rectal and intraperitoneal immunization with protoxin cry1ac from bacillus thuringiensis induces compartmentalized serum, intestinal, vaginal and pulmonary immune responses in balb/c mice. | recently we discovered that the cry1ac protoxin of bacillus thuringiensis administered to balb/c mice intraperitoneally (i.p.) or intragastrically is a systemic and intestinal immunogen as potent as cholera toxin. to further characterize the mucosal immunogenicity of cry1ac we additionally tried the intranasal (i.n.) and rectal routes and used enzyme-linked immunoassays to determine anti-cry1ac antibody responses in the serum as well as in vaginal and tracheobronchial washes and in the fluids of ... | 2000 | 10962271 |
| a leaf-section bioassay for evaluating rice stem borer resistance in transgenic rice containing a synthetic cry1ab gene from bacillus thuringiensis berliner. | 2000 | 10948378 | |
| bacillus thuringiensis var. israelensis (b.t. serotype h-14) against lucilia sericata third stage larvae. | bacillus thuringiensis var. israelensis (b.t. h-14) was mixed with minced liver in different concentrations and given to newly moulted third stage larvae of lucilia sericata. the lc50 was 9 ppm (0.76-1.5) and the slope function was 0.59. this bacterium which is safe and friendly proved to be effective against the myiasis producing l. sericata larvae. | 2000 | 10946517 |
| extended effect of bacillus thuringiensis h-14 on culex pipiens adults surviving larval treatment. | three bacillus thuringiensis h-14 preparations (a laboratory prepared and two commercial formulations namely, tecknar and vectobac) were assayed against third instar culex pipiens larvae in order to trace their toxic activity on larval treatment. the lc50 values were 0.002, 0.02 and 0.04 ppm. respectively. the laboratory strain was tested on the development of culex pipiens. larval mortality, pupation, adult emergence and sex ratio showed significant differences as compared to the non-treated gr ... | 2000 | 10946499 |
| in vitro cytotoxicity of non-cyt inclusion proteins of a bacillus thuringiensis isolate against human cells, including cancer cells. | a soil isolate designated 90-f-45-14, belonging to bacillus thuringiensis serovar dakota (h15), was examined for characterization of in vitro cytotoxicity, associated with parasporal inclusion proteins, against human cells. when activated with proteolytic processing, inclusion proteins of the isolate 90-f-45-14 exhibited a moderate cytotoxicity against the human uterus cervix cancer cells (hela) with an ec(50) value of 60.8 microg ml(-1), while showing extremely high activities on the human leuk ... | 2000 | 10945774 |
| membrane pore architecture of a cytolytic toxin from bacillus thuringiensis. | to investigate the membrane pore structure of cyt2aa1 toxin from bacillus thuringiensis, 14 single-cysteine substitutions of the toxin were constructed. five of these mutants (l172c, v186c, l189c, e214c and l220c) yielded characteristic products when processed by proteinase k; other mutants were degraded by this enzyme. mutants that yielded characteristic proteolysed products and wild-type toxin were labelled with polarity-sensitive acrylodan (6-acryloyl-2-dimethylaminonaphthalene) at the thiol ... | 2000 | 10926854 |
| bacillus thuringiensis (bt) toxin susceptibility and isolation of resistance mutants in the nematode caenorhabditis elegans. | the protein toxins produced by bacillus thuringiensis (bt) are the most widely used natural insecticides in agriculture. despite successful and extensive use of these toxins in transgenic crops, little is known about toxicity and resistance pathways in target insects since these organisms are not ideal for molecular genetic studies. to address this limitation and to investigate the potential use of these toxins to control parasitic nematodes, we are studying bt toxin action and resistance in cae ... | 2000 | 10924467 |
| insecticidal toxin from bacillus thuringiensis is released from roots of transgenic bt corn in vitro and in situ. | the insecticidal toxin encoded by the cry1ab gene from bacillus thuringiensis was released in root exudates from transgenic bt corn during 40 days of growth in soil amended to 0, 3, 6, 9, or 12% (v/v) with montmorillonite or kaolinite in a plant growth room and from plants grown to maturity in the field. the presence of the toxin in rhizosphere soil was determined by immunological and larvicidal assays. no toxin was detected in any soils from isogenic non-bt corn or without plants. persistence o ... | 2000 | 10922501 |
| cloning of a new bacillus thuringiensis cry1i-type crystal protein gene. | a new cry1i-type gene, cry1id1, was cloned from a b. thuringiensis isolate, and its nucleotide sequence was determined. the deduced amino acid sequence of cry1id1 is 89.7%, 87.2%, and 83.4% identical to the cry1ia, cry1ib, and cry1ic proteins, respectively. the upstream sequence of the cry1id1 structural gene was not functional as promoter in b. subtilis. the cry1id1 protein, purified from recombinant e. coli cells, had a toxicity comparable to that of cry1ia against plutella xylostella, but it ... | 2000 | 10919402 |
| laboratory selection for resistance to bacillus sphaericus in culex quinquefasciatus (diptera: culicidae) from california, usa. | a previously untreated field population of culex quinquefasciatus say, collected near bakersfield, ca, was subjected to intensive laboratory selection with the bacterial insecticide bacillus sphaericus neide (strain 2362) at a level producing 95% mortality. resistance rapidly appeared and resistance levels increased such that fourth instars of generation 12 were able to survive a concentration of b. sphaericus that was 7,000 times higher than the median lethal concentration (lc50) of the suscept ... | 2000 | 10916293 |
| bacillus thuringiensis delta-endotoxin proteins show a correlation in toxicity and short circuit current inhibition against helicoverpa zea. | pesticidal activity of bacillus thuringiensis delta-endotoxins, cry1aa, cry1ab, cry1ac, and cry2a, was determined by using the force-feeding bioassay method to 4(th) instar larvae of helicoverpa zea. h. zea was susceptible to bt toxins in the order cry1ac > cry1ab > cry1aa > cry2a with 63.60, 89.04, 159.65, and 375.78 ng/larvae respectively. the abilities of selected bacillus thuringiensis toxins to inhibit short circuit current (i(sc)) in midgut epithelia of h. zea were also investigated by vol ... | 2000 | 10915211 |
| hyper-production of insecticidal crystal protein (delta-endotoxin) by bacillus thuringiensis var. israelensis is not related to sporulation-specific biochemical functions. | hypertoxic mutant strains of bacillus thuringiensis var. israelensis were isolated by mutagenesis of the parent strain. the correlation, if any, between hyper-production of insecticidal crystal protein (delta-endotoxin) by hypertoxic mutant strains of bacillus thuringiensis var. israelensis and sporulation-specific biochemical functions was studied. no increase in sporulation-specific biochemical markers was observed in the hypertoxic mutant strains. asporogenous mutants of hypertoxic mutant str ... | 2000 | 10915205 |
| isolation of tn916-like conjugal elements from swine lot effluent. | isolates of enterococcus faecalis obtained from a swine farrowing house outflow were examined for genetic elements similar to tn916. of the enterococci isolated, 71% were resistant to tetracycline. among the tetracycline-resistant enterococci isolated from the outflow samples, approximately 34% were able to transfer the tetracycline resistance phenotype to bacillus thuringiensis in cross-genus matings. the frequencies of transfer for 10 random isolates were comparable to those for transfer of tn ... | 2000 | 10913976 |
| activation and fragmentation of bacillus thuringiensis delta-endotoxin by high concentrations of proteolytic enzymes. | commercial enzymes and insect gut juice at various concentrations were used to digest bacillus thuringiensis subsp. sotto cry1aa protoxin and examine the fragmentation pattern and effect on insecticidal activity. trypsin at both high (5 mg/ml) and low (0.05 mg/ml) concentrations converted protoxin to toxin with no difference in insecticidal activity against bombyx mori larvae. in both cases, the toxin protein had an apparent m(r) of 58.4 kda (sds-page). active toxin of identical m(r) was also pr ... | 1999 | 10907418 |
| host-plant diversity of the european corn borer ostrinia nubilalis: what value for sustainable transgenic insecticidal bt maize? | the strategies proposed for delaying the development of resistance to the bacillus thuringiensis toxins produced by transgenic maize require high levels of gene flow between individuals feeding on transgenic and refuge plants. the european corn borer ostrinia nubilalis (hübner) may be found on several host plants, which may act as natural refuges. the genetic variability of samples collected on sagebrush (artemisia sp.), hop (humulus lupulus l.) and maize (zea mays l.) was studied by comparing t ... | 2000 | 10902683 |
| effects of transgenic bacillus thuringiensis maize grain on b. thuringiensis-susceptible plodia interpunctella (lepidoptera: pyralidae). | percentage survivorship, developmental time, adult body length, and sex ratio of plodia interpunctella (hübner) reared on field-produced grain from sixteen cultivars of maize, zea mays l., including several transgenic bacillus thuringiensis (bt) berliner hybrids and selected non-bt isolines, were evaluated under laboratory conditions. compared with isolines, development was delayed and survivorship reduced for p. interpunctella reared on grain from transgenic hybrids with the camv/35s promoter t ... | 2000 | 10902364 |
| performance of transgenic corn hybrids in missouri for insect control and yield. | the efficacy of bacillus thuringiensis-transformed corn (zea mays l.) hybrids compared with comparable nontransformed corn hybrids for controlling first- and second-generation european corn borer, ostrinia nubilalis (hübner), and second-generation southwestern corn borer, diatraea grandiosella dyar, was determined. yield comparisons were obtained from the same plots of corn hybrids. both generations of european and the second-generation of southwestern corn borer were effectively controlled, but ... | 2000 | 10902361 |
| susceptibility of plutella xylostella (l.) (lepidoptera: plutellidae) populations in mexico to commercial formulations of bacillus thuringiensis. | populations of diamondback moth, plutella xylostella (l.), sampled from commercial fields of crucifers in three states of mexico, were tested for susceptibility to commercial formulations of bacillus thuringiensis subsp. kurstaki (berliner) (dipel 2x), b. thuringiensis subsp. aizawai (xentari), delta endotoxin cry 1c (mc), and cryia(c) (mvp), and a mixture of b. thuringiensis subsp. kurstaki and subsp. aizawai (agree). leaf-dip bioassays confirmed variation in susceptibility of up to 13-fold for ... | 2000 | 10902356 |
| seed mixtures as a resistance management strategy for european corn borers (lepidoptera: crambidae) infesting transgenic corn expressing cry1ab protein. | dispersal of neonate european corn borers, ostrinia nubilalis (hübner), in seed mixtures of transgenic corn expressing cry1ab protein (bt+) and nontransgenic corn (bt-) was evaluated in a 2-yr field study. the main objective was to determine if larval dispersal limits the effectiveness of seed mixtures as a resistance management strategy. mixtures evaluated included (1) all bt+ plants, (2) every fifth plant bt- with remaining plants bt+, (3) every fifth plant bt+ with remaining plants bt-, and ( ... | 2000 | 10902353 |
| assessment of insecticide resistance after the outbreak of diamondback moth (lepidoptera: plutellidae) in california in 1997. | during an outbreak of the diamondback moth, plutella xylostella (l.), in california in 1997, nine populations were collected from the major broccoli areas throughout the state. populations were assayed for their susceptibility to currently used materials (bacillus thuringiensis subsp. kurstaki, permethrin, and methomyl) and to newer materials that had not yet been commercially used in california (spinosad, emamectin benzoate, and chlorfenapyr). for the currently used insecticides, elevated level ... | 2000 | 10902352 |
| development of diagnostic concentrations for monitoring bacillus thuringiensis resistance in european corn borer (lepidoptera: crambidae). | two candidate diagnostic concentrations of the cry1ab and cry1ac toxins from bacillus thuringiensis corresponding to the lc99 and ec99 (effective concentration that causes 99% growth inhibition) for european corn borer, ostrinia nubilalis (hübner), were determined based on previously obtained baseline data. validation experiments using field-collected european corn borer populations from across north america showed that for cry1ab, a concentration corresponding to the upper limit of the 95% conf ... | 2000 | 10902351 |
| impact of insecticides and surfactant on lettuce physiology and yield. | insecticides are used extensively on lettuce, lactuca sativa l., grown in southwestern arizona because of heavy insect pressure that can potentially reduce lettuce productivity. multiple sprays are made per season to manage these insects in lettuce. one of the major concerns related to extensive insecticide applications in lettuce is the potential subtle impact of insecticides that may reduce lettuce photosynthesis and yield. we conducted field and greenhouse experiments to examine the impact of ... | 2000 | 10902331 |
| effect of insecticides on the diamondback moth (lepidoptera: plutellidae) and its parasitoid diadegma insulare (hymenoptera: ichneumonidae). | studies were conducted to evaluate the toxicity of insecticides to adult diadegma insulare (cresson) and its host the diamondback moth, plutella xylostella (l.). leaf-dip and direct-dip bioassays for diamondback moth larvae and residual bioassays for adults of diamondback moth and d. insulare were used to assess mortalities. larval mortalities at field rates were significantly higher with carbaryl, permethrin, spinosad, and tebufenozide when compared with bacillus thuringiensis, or imidacloprid ... | 2000 | 10902328 |
| laboratory and field evaluations of two bacillus thuringiensis formulations, novodor and raven, for control of cottonwood leaf beetle (coleoptera: chrysomelidae). | laboratory and field experiments were conducted to determine the efficacy of two bacillus thuringiensis berliner formulations, novodor and raven, for controlling cottonwood leaf beetle, chrysomela scripta f. (coleoptera: chrysomelidae). in laboratory bioassays, larvae or adults were added to petri dishes containing populus x euramericana guinier 'eugenei' foliage that had been treated with distilled water (control) or one of the commercial bt formulations at either high or low label rates. survi ... | 2000 | 10902320 |
| cotton boll abscission and yield losses associated with first-instar bollworm (lepidoptera: noctuidae) injury to nontransgenic and transgenic bt cotton. | field tests were conducted in northeastern louisiana to determine the effects of infestations by helicoverpa zea (boddie) on cotton bolls of varying ages. first instars were caged on bolls of nontransgenic ('deltapine 5415') or transgenic bacillus thuringiensis berliner variety kurstaki (bt) ('nucotn 33b') cotton from 29 june to 11 august during 1997 and 1998. deltapine 5415 bolls that accumulated 179 (7.2 d), 281 (11.2 d), and 253 (10.1 d) heat units beyond anthesis were safe from bollworm-indu ... | 2000 | 10902317 |
| sublethal acute and chronic exposure of colorado potato beetle (coleoptera: chrysomelidae) to the delta-endotoxin of bacillus thuringiensis. | sublethal exposure of colorado potato beetle, leptinotarsa decemlineata (say), larvae to the delta-endotoxin of bacillus thuringiensis variety tenebrionis (berliner) caused a dose-dependent reduction in feeding and weight gain when tested in a leaf disk bioassay. the highest doses of chronic (continuous-lower concentration) exposure resulted in peak foliage consumption on day 1 as compared with peak consumption on days 3 and 4 when exposure was acute (24-h higher concentration). dose and exposur ... | 2000 | 10902316 |
| toxicity of insecticides for control of freshwater culex annulirostris (diptera: culicidae) to the nontarget shrimp, caradina indistincta (decapoda: atyidae). | laboratory evaluations were conducted in southeastern queensland, australia, to determine the toxicities of two organophosphate compounds (temephos and pirimiphos-methyl), an insect growth regulator (s-methoprene), and an entomopathogenic bacterium (bacillus thuringiensis variety israelensis de barjac [b.t.i.]) to culex annulirostris (skuse), an australian freshwater mosquito vector of arboviruses, and to caradina indistincta calman, a co-habiting nontarget shrimp species. s-methoprene and b.t.i ... | 2000 | 10902314 |
| field evaluation of soybean engineered with a synthetic cry1ac transgene for resistance to corn earworm, soybean looper, velvetbean caterpillar (lepidoptera: noctuidae), and lesser cornstalk borer (lepidoptera: pyralidae). | a transgenic line of the soybean 'jack', glycine max (l.) merrill, expressing a synthetic cry1ac gene from bacillus thuringiensis variety kurstaki (jack-bt), was evaluated for resistance to four lepidopteran pests in the field. jack-bt and genotypes serving as susceptible and resistant controls were planted in field cages and artificially infested with larvae of corn earworm, helicoverpa zea (boddie), and velvetbean caterpillar, anticarsia gemmatalis (hübner), in 1996, 1997, and 1998, and also w ... | 2000 | 10902306 |
| bt corn pollen impacts on nontarget lepidoptera: assessment of effects in nature. | 2000 | 10899990 | |
| novel insecticidal toxins from nematode-symbiotic bacteria. | the current strategy of using transgenic crops expressing insecticidal protein toxins is placing increasing emphasis on the discovery of novel toxins, beyond those already derived from the bacterium bacillus thuringiensis. here we review the cloning of four insecticidal toxin complex (tc) encoding genes from a different bacterium photorhabdus luminescens and of similar gene sequences from xenorhabdus nematophilus. both these bacteria occupy the gut of entomopathogenic nematodes and are released ... | 2000 | 10892346 |
| [expression of bacillus thuringiensis (bt) crystal toxin gene in the chloroplast of tobacco]. | the 3.5 kb wild-type bt cry i a(c) gene and its 3' truncated forms (2.1 kb, 1.8 kb) were placed under the control of plastid expression signals consisting of the strong light-induced psba promoter and its 3' untranslated region with the aada cassette (prrn, aada and psba3') as a selectable marker. the resulting vectors pbt3, pbt8 and pbt22 also contain flanking tobacco plastid dna homology regions to direct insertion of the bt transgene into the tobacco plastid genome between psba and trnk by ho ... | 2000 | 10887699 |
| parasporin, a human leukemic cell-recognizing parasporal protein of bacillus thuringiensis. | an unusual property, human leukemic cell-recognizing activity, associated with parasporal inclusions of a noninsecticidal bacillus thuringiensis soil isolate was investigated, and a protein (named parasporin in this study) responsible for the activity was cloned. the parasporin, encoded by a gene 2,169 bp long, was a polypeptide of 723 amino acid residues with a predicted molecular weight of 81, 045. the sequence of parasporin contained the five conserved blocks commonly found in b. thuringiensi ... | 2000 | 10882663 |
| cloning and characterization of a bacillus thuringiensis serovar higo gene encoding a novel class of the delta-endotoxin protein, cry27a, specifically active on the anopheles mosquito. | a novel gene encoding a 98-kda mosquitocidal delta-endotoxin protein, designated cry27a, was cloned from a bacillus thuringiensis serovar higo strain. the cry27a protein contained the five sequence blocks of amino acids commonly conserved in most b. thuringiensis cry proteins. relatively high homologies, ranging from 43.0% to 84.4%, existed between the cry27a protein and several established classes of mosquitocidal cry proteins (cry4a, cry10a, cry19a, cry19b, and cry20a) in the sequence of 51 n- ... | 2000 | 10879975 |
| biocontrol of the sugarcane borer eldana saccharina by expression of the bacillus thuringiensis cry1ac7 and serratia marcescens chia genes in sugarcane-associated bacteria. | the cry1ac7 gene of bacillus thuringiensis strain 234, showing activity against the sugarcane borer eldana saccharina, was cloned under the control of the tac promoter. the fusion was introduced into the broad-host-range plasmid pkt240 and the integration vector pjff350 and without the tac promoter into the broad-host-range plasmids pml122 and pkmm0. these plasmids were introduced into a pseudomonas fluorescens strain isolated from the phylloplane of sugarcane and the endophytic bacterium herbas ... | 2000 | 10877771 |
| [integration via tn10 and expression of bti cryiva gene in the chromosome dna of flourescent pseudomonas bacterial strains]. | cryiva gene of the bacillus thuringiensis subsp. israelensis was subcloned into the tn10 of a suicide transposon plasmid vector and a transposon plasmid plf97a carrying cryiva was constructed. by electroporation and transposition, cryiva gene integrated into chromosome dna of f.p.de2. thus the genetic engineered bacterial strain, f.p.de202, was constructed. southern blotting revealed that this integration was happened in different loci of the chromosome. western blotting demonstrated that cryiva ... | 1999 | 10876675 |
| transcription of the insecticidal crystal protein genes of bacillus thuringiensis. | production of a large amount of insecticidal crystal proteins encoded on large plasmids is largely dependent upon the mother cell, bacillus thuringiensis (b. thuringiensis, also bt), specific transcription systems attributable to sporulation. in the middle stages of sporulation, cry4a is most actively transcribed from the promoter cry4a-p1. the proximal transcriptional start point of cry4a, which is under the control of the promoter p1, is used in bacillus subtilis (b. subtilis) in the middle st ... | 2000 | 10874999 |
| mechanisms, ecological consequences and agricultural implications of tri-trophic interactions. | recent research bridging mechanistic and ecological approaches demonstrates that plant attributes can affect herbivores, natural enemies of herbivores, and their interaction. such effects may be genetically variable among plants and/or induced in individual plants by herbivore attack, and are mediated by primary plant attributes (i.e. nutritional quality and physical structure) and defense-related products (i.e. secondary chemicals and plant volatiles), and may be modified by human activity (e.g ... | 2000 | 10873845 |
| noninsecticidal parasporal proteins of a bacillus thuringiensis serovar shandongiensis isolate exhibit a preferential cytotoxicity against human leukemic t cells. | a bacillus thuringiensis isolate, 89-t-34-22, belonging to the serovar shandongiensis (h22) produced noninsecticidal and nonhemolytic proteins crystallizing into irregular-shaped parasporal inclusions. the proteins showed in vitro cytotoxicity to human cells, including cancer cells, only when activated by protease treatment. the human leukemic t (molt-4) cells were > 100 times more susceptible than hela and normal t cells to the proteins of 89-t-34-22. the cytotoxicity was dose dependent and the ... | 2000 | 10872830 |
| effects of sustained-release methoprene and a combined formulation of liquid methoprene and bacillus thuringiensis israelensis on insects in salt marshes. | aquatic insects are an important component of the food web in salt marshes, therefore it is necessary to test whether pesticides used to control mosquitoes in salt marshes are safe for nontarget insects. we tested the nontarget effects of a combined formulation (duplex) of bacillus thuringiensis israelensis (b.t.i.) and liquid methoprene (an insect development regulator) or sustained-release methoprene pellets (altosid(r) pellets) by applying these materials to replicated salt marsh ponds at max ... | 2000 | 10871420 |
| phenotypic and genotypic comparisons of 23 strains from the bacillus cereus complex for a selection of known and putative b. thuringiensis virulence factors. | sixteen bacillus thuringiensis, four bacillus cereus and three bacillus anthracis isolates were screened for a selection of known and putative b. thuringiensis virulence factors. pcr primers were designed to detect genes for phosphatidylcholine specific phospholipase c, phosphatidylinositol specific phospholipase c, immune inhibitor a, vegetative insecticidal protein 3a, a protein proposed to be involved in capsule synthesis, a newly identified ser/thr kinase homologue and enterotoxin ents. moti ... | 2000 | 10867226 |
| the role of amino acid residues in the active site of a midgut microvillar aminopeptidase from the beetle tenebrio molitor. | aminopeptidases are major enzymes in the midgut microvillar membranes of most insects and are targets of insecticidal bacillus thuringiensis crystal delta-endotoxins. sequence analysis and substrate specificity studies showed that these enzymes resemble mammalian aminopeptidase n, although information on the organization of their active site is lacking. the effect of ph at different temperatures on the kinetic parameters of tenebrio molitor (coleoptera) larval aminopeptidase showed that enzyme c ... | 2000 | 10862968 |
| effect of bacillus thuringiensis toxins on the midgut of the nun moth lymantria monacha. | three steps of the proposed mode of action of bacillus thuringiensis toxins have been studied in lymantria monacha. we demonstrated that only the toxins that caused typical pathological changes in midgut epithelial cells and bound to the midgut brush border membrane were able to drastically reduce the midgut transepithelial voltage of the nun moth. | 2000 | 10843836 |
| the interactions between soybean trypsin inhibitor and delta-endotoxin of bacillus thuringiensis in helicoverpa armigera larva. | no significant difference in larval mortality was observed when a sublethal dose of bacillus thuringiensis (bt) var. kurstaki hd-1 crystal was supplemented with soybean trypsin inhibitor (sti) in the artificial diet fed to helicoverpa armigera in the laboratory, but supplementing a nonlethal dose of crystal with sti in the diet led to a pronounced reduction of larval growth. this concentration of crystal and two lower concentrations of sti alone had no significant effects on larval growth. the r ... | 2000 | 10843832 |
| absence of toxicity of bacillus thuringiensis pollen to black swallowtails under field conditions. | a single laboratory study on monarch butterflies has prompted widespread concern that corn pollen, engineered to express bacillus thuringiensis (bt) endotoxin, might travel beyond corn fields and cause mortality in nontarget lepidopterans. among the lepidopterans at high potential risk from this technology is the black swallowtail butterfly, papilio polyxenes, whose host plants in the midwestern u. s. are located principally in narrow strips between roads and crop fields. a field study was perfo ... | 2000 | 10840067 |
| regulation of human pld1 and pld2 by calcium and protein kinase c. | numerous studies show that pld is activated in cells by calcium and by protein kinase c (pkc). we found that human pld1 and pld2 expressed in sf9 cells can be activated by calcium-mobilizing agonists and by co-expression with pkcalpha. the calcium-mobilizing agonists a23187 and cryic toxin triggered large increases in phosphatidylethanol (ptdeth) production in sf9 cells over-expressing pld1 and pld2, but not in vector controls. pld activation by these agonists was largely dependent on extracellu ... | 2000 | 10838164 |
| bacillus anthracis, bacillus cereus, and bacillus thuringiensis--one species on the basis of genetic evidence. | bacillus anthracis, bacillus cereus, and bacillus thuringiensis are members of the bacillus cereus group of bacteria, demonstrating widely different phenotypes and pathological effects. b. anthracis causes the acute fatal disease anthrax and is a potential biological weapon due to its high toxicity. b. thuringiensis produces intracellular protein crystals toxic to a wide number of insect larvae and is the most commonly used biological pesticide worldwide. b. cereus is a probably ubiquitous soil ... | 2000 | 10831447 |
| larval susceptibility of the diamondback moth, plutella xylostella (lepidoptera: plutellidae), to bacillus thuringiensis h serovars isolated in japan. | a total of 1700 japanese strains of bacillus thuringiensis, belonging to at least 47 h serogroups, were examined for insecticidal activity against larvae of the diamondback moth, plutella xylostella. the high-level toxicity was associated with 612 isolates (36.0%). of these, 608 isolates (99.3%) fell into 13 h serogroups belonging to the low-numbered h serotypes, h1-h10. conversely, most isolates belonging to the high-numbered serotypes (>h10) had little or no larvicidal activity; only one isola ... | 2000 | 10830896 |
| bacillus thuringiensis soil populations naturally occurring in the ryukyus, a subtropic region of japan. | of 809 soil samples collected from the seven islands of the ryukyus, japan, 107 samples (13.2%) contained bacillus thuringiensis. the frequency of b. thuringiensis among the b. cereus group was 1.1% (235/21842) on the average. the b. thuringiensis soil populations of the ryukyus consisted of more than 22 h serogroups. the predominant h serotype was the h5ac/21 (serovar canadensis/colmeri), followed by the h3ad (serovar sumiyoshiensis) and h16 (serovar indiana). geographically, most widely distri ... | 2000 | 10830895 |
| recovery of bacillus thuringiensis from marine sediments of japan. | marine sediments from a japanese bay were examined for the occurrence of bacillus thuringiensis. of 1313 colonies belonging to the bacillus cereus/b. thuringiensis group, 22 (1.7%) were allocated to b. thuringiensis. marine isolates of b. thuringiensis consisted of heterogeneous multiple h serogroups; 10 isolates were assigned to the eight serovars (kurstaki, sumiyoshiensis, sotto, aizawai, darmstadiensis, thompsoni, neoleonensis, and higo); two motile isolates failed to react with the reference ... | 2000 | 10827286 |
| isolation and characterization of bacillus thuringiensis strains from aquatic environments in spain. | samples collected from aquatic environments from spain were analyzed for the occurrence and dipteran toxicity of bacillus thuringiensis. from a total of 41 samples, 122 isolates were obtained, yielding a b. thuringiensis index of 0.22. isolates were assigned to 13 different serovars, with serovar thuringiensis (serotype h1) the most frequently found. toxicity tests carried out revealed that eight isolates (6.6% out of the total) were active against tipula oleracea larvae. serological tests assig ... | 2000 | 10827284 |
| effect of plant age, larval age, and fertilizer treatment on resistance of a cry1ab-transformed aromatic rice to lepidopterous stem borers and foliage feeders. | the resistance of vegetative, booting, and flowering stage plants of a variety of an aromatic rice, oryza sativa l., transformed with a bacillus thuringiensis berliner cry1ab gene under control of the maize phosphoenolpyruvate carboxylase (pepc) promoter was evaluated against four lepidopterous rice pests--the stem borers chilo suppressalis (walker) (lepidoptera: crambidae) and scirpophaga incertulas (walker) (lepidoptera: pyralidae), and the foliage feeders cnaphalocrocis medinalis guenée (lepi ... | 2000 | 10826204 |
| evaluation of potato tuber moth (lepidoptera: gelechiidae) resistance in tubers of bt-cry5 transgenic potato lines. | the potato tuber moth, phthorimaea operculella (zeller), in tropical and subtropical countries, is the most destructive pest of potato, solanum tuberosum l. the larvae attack foliage and tubers in the field and in storage. the purpose of this study was to evaluate the efficacy of a bt-cry5 transgene to control the potato tuber moth in tuber tissues. tuber bioassays using stored (11-12 mo old) and newly harvested tubers of bt-cry5-lemhi russet and bt-cry5-atlantic potato lines showed up to 100% m ... | 2000 | 10826202 |
| susceptibility of spanish populations of the corn borers sesamia nonagrioides (lepidoptera: noctuidae) and ostrinia nubilalis (lepidoptera: crambidae) to a bacillus thuringiensis endotoxin. | baseline susceptibility to the cry1ab delta-endotoxin from bacillus thuringiensis (berliner) was determined for four populations of sesamia nonagrioides (lefebvre) and two populations of ostrinia nubilalis (hübner) from spain. this study shows that s. nonagrioides is at least as susceptible as o. nubilalis to b. thuringiensis cry1ab protein. we found small differences in susceptibility among the spanish populations of s. nonagrioides that can be attributed to natural variation, because there are ... | 2000 | 10826200 |
| assessment of microencapsulated formulations for improved residual activity of bacillus thuringiensis. | bacillus thuringiensis berliner is a highly efficacious bioinsecticide used to control lepidopteran pests in the field. unfortunately, it has limited residual activity on plants because sunlight inactivates spores and crystals and they can be washed off by rain. to minimize loss of activity, formulations must contain uv protectants, stickers, or both. we tested approximately 80 formulations and determined optimal combinations of ingredients and spray drying conditions for improving b. thuringien ... | 2000 | 10826165 |
| simulating the impact of cross resistance between bt toxins in transformed clover and apples in new zealand. | simulation were conducted to guide development of resistance management strategies aimed at prolonging the usable life of b. thuringiensis (bt) endotoxins in multiple cropping situations, where different crops expressing bt endotoxins are host plants for a common pest. we used the new zealand apple and clover model ecosystem to explore the relative impact on the rate of resistance development of varying levels of cross-resistance between different toxins expressed in these 2 potentially bt-trans ... | 2000 | 10826160 |
| determination of affinity and kinetic rate constants using surface plasmon resonance. | 2000 | 10820723 | |
| structure-function analysis of cysteine-engineered entomopathogenic toxins. | 2000 | 10820718 | |
| impacts of a mosquito selective pesticide, bti, on the macroinvertebrates of a subtropical stream in hong kong. | to test the hypothesis that bti was specific to mosquito larvae, the granular form of bti was tested on commonly found hong kong species from four naturally occuring aquatic insect orders and one species of decapod crustacean (neocardina serra). because data on bti impacts on species in tropical and subtropical countries is relatively rare, the present study was conducted in hong kong's new territories. using static acute toxicity bioassays, all mosquito larvae exposed to bti at the recommended ... | 2000 | 10819203 |
| enhanced toxicity of bacillus thuringiensis cry3a delta-endotoxin in coleopterans by mutagenesis in a receptor binding loop. | we used site-directed mutagenesis to modify the bacillus thuringiensis cry3a gene in amino acid residues 350-354. two mutant toxins, a1 (r(345)a,y(350)f,y(351)f) and a2 (r(345)a,deltay(350), deltay(351)), showed significantly improved toxicity against tenebrio molitor (yellow mealworm). the mutant toxin a1 was also more potent against both leptinotarsa decemlineata (colorado potato beetle) and chrysomela scripta (cottonwood leaf beetle), while a2 displayed enhanced toxicity only in l. decemlinea ... | 2000 | 10812080 |
| kinetic properties of the channels formed by the bacillus thuringiensis insecticidal crystal protein cry1c in the plasma membrane of sf9 cells. | spectrofluorimetric measurements were conducted to quantify, in real-time, membrane permeability changes resulting from the treatment of sf9 insect cells (spodoptera frugiperda, lepidoptera) with different bacillus thuringiensis cry insecticidal proteins. coumarin-derived cd222 and merocyanin-540 probes were respectively used to monitor extracellular k(+) and membrane potential variations upon sf9 cells incubation with cry toxins. our results establish that cry1c induces, after a delay, the depo ... | 2000 | 10811973 |
| insertion and organization within membranes of the delta-endotoxin pore-forming domain, helix 4-loop-helix 5, and inhibition of its activity by a mutant helix 4 peptide. | the pore-forming domain of bacillus thuringiensis cry1ac insecticidal protein comprises of a seven alpha-helix bundle (alpha1-alpha7). according to the "umbrella model," alpha4 and alpha5 helices form a hairpin structure thought to be inserted into the membrane upon binding. here, we have synthesized and characterized the hairpin domain, alpha4-loop-alpha5, its alpha4 and alpha5 helices, as well as mutant alpha4 peptides based on mutations that increased or decreased toxin toxicity. membrane per ... | 2000 | 10811807 |
| gm crops: environmental risks and non-target effects. | 2000 | 10809593 | |
| eu court overrules france's bt maize ban. | 2000 | 10802608 | |
| bivalent sequential binding model of a bacillus thuringiensis toxin to gypsy moth aminopeptidase n receptor. | specificity for target insects of bacillus thuringiensis insecticidal cry toxins is largely determined by toxin affinity for insect midgut receptors. the mode of binding for one such toxin-receptor complex was investigated by extensive toxin mutagenesis, followed by real-time receptor binding analysis using an optical biosensor (biacore). wild-type cry1ac, a three-domain, lepidopteran-specific toxin, bound purified gypsy moth (lymantria dispar) aminopeptidase n (apn) biphasically. site 1 display ... | 2000 | 10799525 |
| [characterization of entomopathogenic bacillus samples isolated in senegal and study of their toxicity for malaria vectors]. | a screening program developed in senegal to isolate new strains of entomopathogenic bacillus has led to the isolation of 194 strains of bacillus thuringiensis and 9 strains of bacillus sphaericus from various sites and insect samples. the characterization of these strains regarding their h serotype, their crystal composition and their toxicity against mosquitoes (culex pipiens, aedes aegypti and anopheles stephensi) has led to the isolation of 27 mosquitocidal strains. as malaria is an important ... | 1998 | 10797955 |
| [bacillus thuringiensis: a biotechnology model]. | this paper is on the different biotechnological approaches that have been used to improve bacillus thuringiensis (bt) for the control of agricultural insect pests and have contributed to the successful use of this biological control agent; it describes how a better knowledge of the high diversity of bt strains and toxins genes together with the development of efficient host-vector systems has made it possible to overcome a number of the problems associated with bt based insect control measures. ... | 1999 | 10783711 |
| cry1ac protoxin from bacillus thuringiensis sp. kurstaki hd73 binds to surface proteins in the mouse small intestine. | bacillus thuringiensis (bt), considered a safe insecticide, produces insecticidal proteins named cry during sporulation, which possess exceptional immunological properties. in this work using an immunohistochemical test we demonstrated that cry1ac protoxin (pcry1ac) binds to the mucosal surface of the mouse small intestine. ligand blot assay allowed us to detect, under denaturing conditions, six pcry1ac-binding polypeptides present in brush border membrane vesicles isolated from the small intest ... | 2000 | 10777680 |
| [effect of chitosan derivatives on the development of phage infection in cultured bacillus thuringiensis]. | the influence of chitosan fragments with different degrees of polymerization and some chemical chitosan derivatives on the infection of bacillus thuringiensis by phage 1-97a was studied. it was shown that chitosan inhibits phage infection and inactivates phage particles. the extent of inhibition of phage infection inversely depended on the degree of polymerization of chitosan fragments. on the contrary, the extent of inactivation of phage virulence was proportional to the degree of polymerizatio ... | 2000 | 10776629 |
| activation and germination of spores of bacillus thuringiensis var israelensis by alkaline ph and larval (aedes aegypti) gut fluid. | alkaline activation of the spores of crystalliferous (cry+) and acrystalliferous (cry-) strains of bacillus thuringiensis var israelensis; wild type b. cereus and its transcipient crystalliferous derivatives and wild type b. subtilis was studied. also the effect of larval (aedes aegypti) gut fluid on the activation of spores of these strains was studied. only the spores of the crystal forming strains were found to be activated by 0.1 m k2co3 (ph 10) and by the larval gut fluid. the process of al ... | 1999 | 10774706 |
| cross-resistance to bacillus sphaericus strains in culex quinquefasciatus resistant to b. sphaericus 1593m. | bacillus sphaericus 1593m resistant larvae of culex quinquefasciatus were reared in the laboratory since 1995. resistance in the larvae was monitored by subjecting selection pressure using b. sphaericus 1593m at every generation. bioassays were conducted with different strains of b. sphaericus (bs 2297, bs 2362 and bs iab 59) and confirmed cross-resistance in the present study. the level ranged between 27.3 to 18.2 fold in comparison with susceptible larvae. but bacillus thuringiensis var israel ... | 1999 | 10774654 |
| prevalence and transovum transmission of bacillus thuringiensis berliner in a navel orangeworm colony. | 2000 | 10772330 | |
| screening and characterization of bacillus thuringiensis isolates from brazil for the presence of coleoptera-specific cry genes. | forty-three bacillus thuringiensis isolates from brazil and 3 from argentina were screened, using the polymerase chain reaction (pcr), for various coleoptera-specific cry genes. seven isolates produced specific and/or nonspecific dna fragments in a pcr reaction with primers specific for two coleopteran cry genes and 4 of these produced dna fragments with primers specific for 7 known coleopteran cry genes. these isolates showed, by electron microscopy, the presence of spherical crystals. they als ... | 2000 | 10772158 |
| field trials of three concentrations of laginex as biological larvicide compared to vectobac-12as as a biocontrol agent for culex quinquefasciatus. | laginex as biological larvicide (lagenidium giganteum) and vectobac-12as (bacillus thuringiensis var. israelensis) were compared in plastic pools containing laboratory-reared culex quinquefasciatus larvae located in a wooded area in panama city, fl, in august and september 1997. the pools were dipped at 2-day intervals to assess larval control. sentinel larvae in screen-sided cups were added to all treatment and control pools at 4-day intervals and evaluated for infection at 48 h. laginex produc ... | 2000 | 10757483 |
| biocidal activity of bacillus species for anopheles larvae. | it is generally accepted that bacillus thuringiensis (b.t.) is specifically toxic to some insects but does not pose any threat to the environment, operators, or consumers. there are several other bacillus species which can be used as effective bioinsecticides. in this study four different species of bacillus, i.e., b. coagulans, b. megaterium, b. brevis, and b. sphaericus were isolated from soil samples collected from kala shah kakoo and kasur areas, in the suburbs of lahore. isolated bacillus s ... | 1999 | 10754794 |
| toxins and genetically modified food. | 2000 | 10752731 | |
| microbial control of mosquitoes with special emphasis on bacterial control. | there are a number of microbial agents including fungus, protozoa, virus and bacteria which act as mosquitocidal agents. however, among these agents, bacillus thuringiensis var israelensis and b. sphaericus are the most potent mosquitocidal agents. bacillus thuringiensis var israelensis and b. sphaericus are gram-positive sporulating bacteria which produce protoxin crystals during sporulation and are highly toxic to susceptible mosquito larvae when they ingest them. these bacterial agents are en ... | 1998 | 10748561 |
| isolation of bacillus thuringiensis from northern victoria land, antarctica. | sixty-two samples of antarctic soils, mosses, penguin guano, algae and lichens were examined for the presence of aerobic endospore-forming bacteria; 36 samples (58%) yielded such organisms, and two samples from edmonson point (74 degrees 21's 165 degrees 08'e) and one sample from apostrophe island (73 degrees 32's 167 degrees 24'e), northern victoria land, yielded strains of bacillus thuringiensis. further isolations from two of the samples, appreciable variation in biotypes among the strains, f ... | 2000 | 10747263 |
| genetic structure of population of bacillus cereus and b. thuringiensis isolates associated with periodontitis and other human infections. | the genetic diversity and relationships among 35 bacillus cereus and bacillus thuringiensis isolates recovered from marginal and apical periodontitis in humans and from various other human infections were investigated using multilocus enzyme electrophoresis. the strains were isolated in norway, except for three strains isolated from periodontitis patients in brazil. the genetic diversity of these strains was compared to that of 30 isolates from dairies in norway and finland. allelic variation in ... | 2000 | 10747152 |
| bacillus thuringiensis delta-endotoxin cry1c domain iii can function as a specificity determinant for spodoptera exigua in different, but not all, cry1-cry1c hybrids. | in order to test our hypothesis that bacillus thuringiensis delta-endotoxin cry1ca domain iii functions as a determinant of specificity for spodoptera exigua, regardless of the origins of domains i and ii, we have constructed by cloning and in vivo recombination a collection of hybrid proteins containing domains i and ii of various cry1 toxins combined with domain iii of cry1ca. cry1ab, cry1ac, cry1ba, cry1ea, and cry1fa all become more active against s. exigua when their domain iii is replaced ... | 2000 | 10742242 |
| a binding site for bacillus thuringiensis cry1ab toxin is lost during larval development in two forest pests. | the insecticidal activity and receptor binding properties of bacillus thuringiensis cry1a toxins towards the forest pests thaumetopoea pityocampa (processionary moth) and lymantria monacha (nun moth) were investigated. cry1aa, cry1ab, and cry1ac were highly toxic (corresponding 50% lethal concentration values: 956, 895, and 379 pg/microl, respectively) to first-instar t. pityocampa larvae. during larval development, cry1ab and cry1ac toxicity decreased with increasing age, although the loss of a ... | 2000 | 10742241 |