Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| fine structural changes in the ileum of mice fed on delta-endotoxin-treated potatoes and transgenic potatoes. | the present work has been designed to study the effect of feeding on transgenic potatoes, which carry the cryi gene of bacillus thuringiensis var. kurstaki strain hd1, on the light and electron microscopic structure of the mice ileum, in comparison with feeding on potatoes treated with the 'delta-endotoxin' isolated from the same bacterial strain. the microscopic architecture of the enterocytes of the ileum of both groups of mice revealed certain common features such as the appearance of mitocho ... | 1998 | 10441029 |
| organic residue decomposition: the minicontainer-system a multifunctional tool in decomposition studies. | the minicontainer-test, first described by eisenbeis (1993), was designed to study the kinetics of organic residue decomposition at a microsite level. it is derived from the litterbag technique and consists of polyethylene minicontainers (volume about 1.5 cm(3)) filled with a test substrate (litter, straw, cellulose, etc.). the minicontainers (mcs) are closed at either end with plastic gauze discs of variable mesh size (e.g. 20 microm, 250 microm, 500 microm or 2 mm). a definite number of such u ... | 1999 | 19005666 |
| suppression of meloidogyne hapla and its damage to lettuce grown in a mineral soil amended with chitin and biocontrol organisms. | chitin was used as soil amendment in fiberglass field microplots, alone or with one or a combination of two to three species of hirsutella rhossiliensis, paecilomyces marquandii, verticillium chlamydosporium, bacillus thuringiensis, and streptomyces costaricanus. sudangrass and rapeseed were planted as cover crops and incorporated into soil as green manure amendments. chitin amendment alone increased the marketable yield of lettuce in 1995 and reduced root-galling ratings and the reproduction of ... | 1999 | 19270942 |
| differential activity and activation of bacillus thuringiensis insecticidal proteins in diamondback moth, plutella xylostella. | whole-crystal preparations from strains hd-1 and hd-133, activated cry1ab and cry1c toxins as well as cry1aa, cry1ac, cry1d, and cry2aa protoxins were tested for toxicity to 2nd-instar larvae of the diamondback moth, plutella xylostella. mortality data recorded after 2 and 5 days provided different results that were related to differential rates of solubilization, activation, and degradation of insecticidal crystal proteins. the two most active proteins are cry1ab and cry1c, which are both prese ... | 1999 | 10441730 |
| bollworms, genes and ecologists. | 1999 | 10448848 | |
| development time and resistance to bt crops. | 1999 | 10448853 | |
| antibiotic mic/mbc analysis of bacillus-based commercial insecticides: use of bioreduction and dna-based assays. | minimum inhibitory concentration (mic) assays, monitored by colony counts, growth (turbidity) and bioreduction of non-toxic xtt [2,3-bis (2-methoxy-4-nitro-5-sulphophenyl)-2h-tetrazolium-5-carboxanilide, inner salt], were used to assess the performance of several types of antibiotics against: (1) commercial bt products made from scale-up sporulation phase cultures of bacillus thuringiensis subsp israelensis (bti) and subsp kurstaki (btk); (2) vegetative cells derived from these bt products; and ... | 1999 | 10455482 |
| inorganic phosphate regulates cryiva protoxin expression in bacillus thuringiensis israelensis. | the role of nutritional factors during cryiva protoxin expression in bacillus thuringiensis israelensis (bti) has been investigated. inorganic phosphate (pi) was found to stimulate 135 kd protoxin synthesis by bti cells. there was a corresponding increase in the cryiva specific mrna in the presence of pi. inorganic phosphate inhibited hpr kinase but activated hpr phosphatase, the two enzymes responsible for regulating the concentration of phosphorylated hpr in the cell. addition of protein phosp ... | 1999 | 10462480 |
| a comparison of the kinetics of plasmid transfer in the conjugation systems encoded by the f plasmid from escherichia coli and plasmid pcf10 from enterococcus faecalis. | quantitative measurements of horizontal dna transfer are critical if one wishes to address questions relating to ecology, evolution and the safe use of recombinant bacteria. traditionally, the efficiency of a conjugation system has been described by its transfer frequency. however, transfer frequencies can be determined in many ways and may be sensitive to physical, chemical and biological conditions. in this study the authors have used the mechanistic similarity between bacterial conjugation an ... | 1999 | 10463166 |
| field studies with the bacterial larvicide inpalbac for simulium spp. control in rio grande do sul, brazil. | 1999 | 10464417 | |
| a new strain of bacillus thuringiensis serovar israelensis very active against blackfly larvae. | 1999 | 10464418 | |
| [the construction and use of inosine-containing primers for searching for and identifying the genes of insecticidal crystal proteins in bacillus thuringiensis]. | the specific to 3 types of cry genes primers containing inosine were constructed to find crystal insecticidal protein bacillus thuringiensis genes using pcr. a number of new b. thuringiensis strains isolated in ukraine were investigated using these pcr primers. as a results, cry genes were found, some of them were identified and demonstrated high homology to cry1ba2 and cry1bc genes. | 1999 | 10465846 |
| protease interactions with bacillus thuringiensis insecticidal toxins | the microbe bacillus thuringiensis (bt) produces crystals that contain insecticidal crystal proteins (icps) used to control many major pests. icps are degraded by proteases from a variety of sources, including those endogenous to the bacterium, those purified from animals and plants, or those found in insects. proteases in the bacterium function in protein metabolism during sporulation; in some cases they hydrolyze icps. insect proteases are implicated in bt toxin specificity, mode of action and ... | 1999 | 10467052 |
| resistance to bacillus thuringiensis cry1ac toxin in three strains of heliothis virescens: proteolytic and sem study of the larval midgut | in a previous study, we demonstrated that resistance to bacillus thuringiensis toxins in heliothis virescens might be related to differences in the composition of the proteolytic extracts from insect midgut. there, we found specific proteolytic bands present in the gut extracts of the resistant strain and absent from the susceptible one. here we report related facts using a new resistant strain (kcb) and a cross between the two strains used in our previous study. as would be expected, no quantit ... | 1999 | 10467056 |
| false reports and the ears of men. | 1999 | 10471903 | |
| development and field performance of a broad-spectrum nonviable asporogenic recombinant strain of bacillus thuringiensis with greater potency and uv resistance. | the main problems with bacillus thuringiensis products for pest control are their often narrow activity spectrum, high sensitivity to uv degradation, and low cost effectiveness (high potency required). we constructed a sporulation-deficient sigk(-) b. thuringiensis strain that expressed a chimeric cry1c/ab gene, the product of which had high activity against various lepidopteran pests, including spodoptera littoralis (egyptian cotton leaf worm) and spodoptera exigua (lesser [beet] armyworm), whi ... | 1999 | 10473413 |
| activity spectra of bacillus thuringiensis delta-endotoxins against eight insect cell lines. | eight continuous insect cell lines were tested for susceptibility to the delta-endotoxins of several lepidopteran-active strains and cloned-gene products of bacillus thuringiensis. the assays were performed on cells suspended in agarose gel, which allowed the toxins activated at ph 10.5 to be applied directly in a high-ph buffer without causing solvent toxicity to the cells. the responses of the cell lines to the various toxins produced activity spectra that were used to identify functionally si ... | 1999 | 10475277 |
| field evaluation of new water-dispersible granular formulations of bacillus thuringiensis ssp. israelensis and bacillus sphaericus against culex mosquitoes in microcosms. | a variety of formulations of bacillus thuringiensis var. israelensis de barjac (b.t.i.) and bacillus sphaericus neide (b.s.) have been studied for mosquito control under laboratory and field conditions. high efficacy, specificity, low risk of development of resistance, long shelf-life, and transportability, as well as the safety to nontarget organisms of these 2 microbial agents have been well documented. some of the currently available formulations of b.t.i. and b.s. have low potency per unit m ... | 1999 | 10480128 |
| residual activity of bacillus thuringiensis serovars medellin and jegathesan on culex pipiens and aedes aegypti larvae. | bacillus thuringiensis serovar medellin strain 163-131 and bacillus thuringiensis serovar jegathesan (b.t.jeg.) strain 367 are very toxic to mosquito larvae. however, they are 10 times less toxic than bacillus thuringiensis var. israelensis (b.t.i.) to mosquito larvae under laboratory conditions. lyophilized powders were produced from these strains and their toxicities were compared to that of powder produced from the b.t.i. strain. larvicidal activity was titrated using aedes aegypti (bora-bora ... | 1999 | 10480130 |
| development of the first black fly (diptera: simuliidae) management program in argentina and comparison with other programs. | in response to increasing pest populations of black flies, the government of argentina initiated a pilot program to evaluate the effectiveness of larval control in the irrigation system of the negro river valley, an 18,240-km2 area in patagonia. the extensive system of irrigation canals, drainage ditches, and natural waterways not only provides water for agriculture and general habitation but also affords habitat for immature black flies. three species (simulium bonaerense, simulium wolffhuegeli ... | 1999 | 10480133 |
| amino acid substitution in alpha-helix 7 of cry1ac delta-endotoxin of bacillus thuringiensis leads to enhanced toxicity to helicoverpa armigera hubner. | insecticidal proteins or delta-endotoxins of bacillus thuringiensis are highly toxic to a wide range of agronomically important pests. the toxins are formed of three structural domains. the n-terminal domain is a bundle of eight alpha-helices and is implicated in pore formation in insect midgut epithelial membranes. all the delta-endotoxins share a common hydrophobic motif of eight amino acids in alpha-helix 7. a similar motif is also present in fragment b of diphtheria toxin (dt). site-directed ... | 1999 | 10481060 |
| insecticidal activity of strains of bacillus thuringiensis on larvae and adults of bactrocera oleae gmelin (dipt. tephritidae). | the olive fly, bactrocera oleae, is the key pest on olives in the mediterranean area. the pest can destroy, in some cases, up to 70% of the olive production. its control relies mainly on chemical treatments, sometimes applied by aircraft over vast areas, with their subsequent ecological and toxicological side effects. bacillus thuringiensis is a spore-forming soil bacterium which produces a protein crystal toxic to some insects, including the orders of lepidoptera, diptera, and coleoptera and ot ... | 1999 | 10486224 |
| effect of bacillus thuringiensis ssp. israelensis on the development of plasmodium gallinaceum in aedes aegypti (diptera: culicidae). | adult, female aedes aegypti, some of which had survived a sublethal dose (lc50) of bacillus thuringiensis ssp. israelensis (bti) as larvae, were fed on chickens with gametocytaemia of plasmodium gallinaceum. parasite development was monitored by dissecting samples of the mosquitoes immediately after the feed and on days 1, 7 and 9 post-feed, to check for the presence of gametocytes, ookinetes, oocysts and sporozoites, respectively. as the proportions of batches of fed mosquitoes found positive f ... | 1999 | 10492676 |
| analysis of mutations in the pore-forming region essential for insecticidal activity of a bacillus thuringiensis delta-endotoxin. | the bacillus thuringiensis insecticidal delta-endotoxins have a three-domain structure, with the seven amphipathic helices which comprise domain i being essential for toxicity. to better define the function of these helices in membrane insertion and toxicity, either site-directed or random mutagenesis of two regions was performed. thirty-nucleotide segments in the b. thuringiensis cry1ac1 gene, encoding parts of helix alpha4 and the loop connecting helices alpha4 and alpha5, were randomly mutage ... | 1999 | 10498724 |
| biotech companies must get back to basics to weigh up risks. | 1999 | 10499565 | |
| green-tissue-specific expression of a reconstructed cry1c gene encoding the active fragment of bacillus thuringiensis delta-endotoxin in haploid tobacco plants conferring resistance to spodoptera litura. | the dna sequence of a truncated cry1c gene encoding the active fragment of bacillus thuringiensis (bt) delta-endotoxin was fully reconstructed by introduction of silent mutations. each of the truncated wild type and the synthetic genes encoding the active fragment of the protoxin was introduced into haploid tobacco plants under the control of the rbcs promoter. to facilitate selection of transgenic tobacco plants with high insecticidal activity, a fusion gene encoding both rat cyp1a1 cytochrome ... | 1999 | 10501003 |
| interplant movement of heliothis virescens (lepidoptera: noctuidae) larvae in pure and mixed plantings of cotton with and without expression of the cry1ac delta-endotoxin protein of bacillus thuringiensis berliner. | laboratory and field studies were conducted during 1993 and 1994 to quantify interplant movement of heliothis virescens (f.) larvae in pure and mixed plantings of cotton, gossypium hirsutum l., with ('event 531') and without ('coker 312') the expression of cry1ac delta-endotoxin protein of bacillus thuringiensis berliner. field studies were conducted with neonate, 4-, and 7-d-old larvae placed on 3-plant experimental units and observed at 24, 48, 72, and 96 h after inoculation of larvae. combini ... | 1999 | 10504897 |
| [identification and characterization of strains of bacillus thuringiensis by genomic fingerprinting using biotinylated phage m13 dna]. | genomic dna of the entomopathogenic bacterium bacillus thuringiensis was analyzed by the genomic fingerprinting technique. the biotin-labeled single-stranded dna of the phage m13 was used as a marker of hypervariable sequences. a procedure for analyzing the differentiation among various bacillus thuringiensis strains was developed. characteristic patterns of fingerprints were obtained for several strains, the main representatives of subspecies that are most frequently used in the manufacture of ... | 1999 | 10505264 |
| identification of bacillus thuringiensis delta-endotoxin cry1c domain iii amino acid residues involved in insect specificity. | cry1c domain iii amino acid residues involved in specificity for beet armyworm (spodoptera exigua) were identified. for this purpose, intradomain iii hybrids between cry1e (nontoxic) and cry1e-cry1c hybrid g27 (toxic) were made. crossover points of these hybrids defined six sequence blocks containing between 1 and 19 of the amino acid differences between cry1e and g27. blocks b, c, d, and e of g27 were shown to be required for optimal activity against s. exigua. block e was also required for opt ... | 1999 | 10508062 |
| identification of residues in domain iii of bacillus thuringiensis cry1ac toxin that affect binding and toxicity. | alanine substitution mutations in the cry1ac domain iii region, from amino acid residues 503 to 525, were constructed to study the functional role of domain iii in the toxicity and receptor binding of the protein to lymantria dispar, manduca sexta, and heliothis virescens. five sets of alanine block mutants were generated at the residues (503)ss(504), (506)nni(508), (509)qnr(511), (522)st(523), and (524)st(525). single alanine substitutions were made at the residues (509)q, (510)n, (511)r, and ( ... | 1999 | 10508083 |
| production of chymotrypsin-resistant bacillus thuringiensis cry2aa1 delta-endotoxin by protein engineering. | cleavage of the cry2aa1 protoxin (molecular mass, 63 kda) from bacillus thuringiensis by midgut juice of gypsy moth (lymantria dispar) larvae resulted in two major protein fragments: a 58-kda fragment which was highly toxic to the insect and a 49-kda fragment which was not toxic. in the midgut juice, the protoxin was processed into a 58-kda toxin within 1 min, but after digestion for 1 h, the 58-kda fragment was further cleaved within domain i, resulting in the protease-resistant 49-kda fragment ... | 1999 | 10508095 |
| multiple roles for tnpi recombinase in regulation of tn5401 transposition in bacillus thuringiensis. | tn5401 is a class ii transposable element derived from the gram-positive bacterium bacillus thuringiensis. the 4,837-bp transposon encodes a tn3-like transposase (tnpa) and an integrase-like recombinase (tnpi) and is notable for its unusually long 53-bp terminal inverted repeats (tirs). the tnpa and tnpi genes are transcribed from a common promoter, designated p(r), that is subject to negative regulation by tnpi. the tirs of tn5401 each contain a 38-bp sequence that can be aligned with the 38- t ... | 1999 | 10515914 |
| lectin activity of bacillus thuringiensis parasporal inclusion proteins. | parasporal inclusion proteins from a total of 151 bacillus thuringiensis strains, consisting of 139 japanese isolates and the type strains of 12 h serovars, were screened for haemagglutination (ha) activity against sheep erythrocytes. of 58 b. thuringiensis strains with ha activity, nine strains exhibited high activity and the remaining 49 strains were moderately active. the strains with high ha activity were derived from phylloplanes and soils of five geographically different localities, and be ... | 1999 | 10518745 |
| bioassay to assess the toxicity of bacillus thuringiensis to daikon leaf beetle (coleoptera: chrysomelidae) | we developed a new method to rear daikon leaf beetles, phaedon brassicae baly (coleoptera: chrysomelidae), on a diet of cruciferae leaves in a growth chamber. eggs were stored at 4 degrees c for 30 days without significant loss of viability. a bioassay using artificial diet was developed to standardize the assessment of toxicity of a powdered crystal-spore preparation of bacillus thuringiensis strain ybt-0618 to p. brassicae larvae. when the diet containing this powder preparation was stored at ... | 1999 | 10534412 |
| helix 4 of the bacillus thuringiensis cry1aa toxin lines the lumen of the ion channel. | the mode of action of bacillus thuringiensis insecticidal proteins is not well understood. based on analogies with other bacterial toxins and ion channels, we hypothesized that charged amino acids in helix 4 of the cry1aa toxin are critical for toxicity and ion channel function. using plutella xylostella as a model target, we analyzed responses to cry1aa and eight proteins with altered helix 4 residues. toxicity was abolished in five charged residue mutants (e129k, r131q, r131d, d136n, d136c), h ... | 1999 | 10542230 |
| partial purification and characterization of bacillus thuringiensis cry1a toxin receptor a from heliothis virescens and cloning of the corresponding cdna. | although extensively studied, the mechanism of action of insecticidal bacillus thuringiensis cry toxins remains elusive and requires further elucidation. toxin receptors in the brush border membrane demand particular attention as they presumably initiate the cascade of events leading to insect mortality after toxin activation. the 170-kda cry1ac toxin-binding aminopeptidase from the tobacco budworm (heliothis virescens) was partially purified, and its corresponding cdna was cloned. the cdna enco ... | 1999 | 10543783 |
| the cadherin-like protein is essential to specificity determination and cytotoxic action of the bacillus thuringiensis insecticidal cryiaa toxin. | the bacillus thuringiensis cryiaa toxin binds a cadherin-like protein (btr175) on the brush-border membranes of the bombyx mori midgut columnar cells, which are the targets. by introducing the btr175 gene with a baculovirus, spodoptera frugiperda sf9 cells expressed btr175 protein on the cell membrane and became susceptible to the cryiaa toxin. the toxin bound the cadherin repeat adjacent to the membrane and made a pore that passed inorganic ions, causing the cell to swell and burst. this was no ... | 1999 | 10544269 |
| refined, circular restriction map of the bacillus thuringiensis subsp. israelensis plasmid carrying the mosquito larvicidal genes. | all the genetic elements responsible for the mosquito larval toxicity of bacillus thuringiensis subsp. israelensis are located on one of its largest plasmids, nicknamed pbtoxis. two linkage groups (with sizes of about 75 and 55 kb) have previously been mapped partially with respect to saci and bamhi restriction sites (ben-dov et al., 1996), but linking them to a single circular plasmid unambiguously was impossible with the available data. to finalize the plasmid map, another rare cutting restric ... | 1999 | 10545261 |
| facts and hypotheses. | 1999 | 10545871 | |
| gmo roundup. | 1999 | 10545872 | |
| green fluorescent protein as a marker for expression of a second gene in transgenic plants. | the use of transgenic crops has generated concerns about transgene movement to unintended hosts and the associated ecological consequences. moreover, the in-field monitoring of transgene expression is of practical concern (e.g., the underexpression of an herbicide tolerance gene in crop plants that are due to be sprayed with herbicide). a solution to these potential problems is to monitor the presence and expression of an agronomically important gene by linking it to a marker gene, such as gfp. ... | 1999 | 10545923 |
| two types of entomocidal crystals of bacillus thuringiensis ssp. finitimus have the same set of unique delta-endotoxins. | the strain b-1166 differs from the other strains of bacillus thuringiensis ssp. finitimus because it has two crystal types with different localization in the sporulating cell, i.e., inside and outside of exosporium membrane. two dissociants of the strain were obtained containing only one of the crystal types. the initial strain produces at least three various delta-endotoxins (fin2, fin3, and fin5) differing from all other known entomocidal proteins; fin2 and fin3 are similar to each other but d ... | 1999 | 10561558 |
| membrane proteins of aedes aegypti larvae bind toxins cry4b and cry11a of bacillus thuringiensis ssp. israelensis. | proteins of molecular weight 65 and 62 kd and having affinity for toxins cry4b and cry11a produced by bacillus thuringiensis ssp. israelensis have been isolated from brush border membranes of aedes aegypti larvae using affinity chromatography. using a ligand blotting technique, we show that the binding of these proteins to the biotinylated toxins is reversible and that the two toxins compete for binding to the two proteins. these proteins are likely to be cry4b and cry11a toxin receptors in gut ... | 1999 | 10561564 |
| [the effect of a soil extract on the development of bacillus thuringiensis and on its synthesis of an insecticidal endotoxin]. | selection of effective and inexpensive nutrient medium for cultivation of entomopathogenic bacteria bacillus thuringiensis was carried out. the medium with molasses [correction of patoka], corn extract and mineral salts has been chosen. addition of a soil extract to the medium enhanced growth of microorganisms, increased the rate of culture development, the yield of spore-crystalline material and quantity of synthesized endotoxin. apparently the strengthening effect belongs to humic substances c ... | 1999 | 10565149 |
| 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 |
| characterization of bacillus thuringiensis serovar bolivia (serotype h63), a novel serovar isolated from the bolivian high valleys. | the type strain bacillus thuringiensis var. bolivia (serotype h63), isolated from the bolivian high valleys, has been characterized at different levels. its parasporal crystal has an unusual shape and it is composed of a protein of 155 kda which shows two bands of 75 and 80 kda after activation. analysis by pcr shows the presence of cry1 genes, and amplification with specific primers gave products for cry1 e, cry1 d, cry4 a and cry4 b with sizes different to those expected. immunoblotting tests ... | 1999 | 10389260 |
| mutations of loop 2 and loop 3 residues in domain ii of bacillus thuringiensis cry1c delta-endotoxin affect insecticidal specificity and initial binding to spodoptera littoralis and aedes aegypti midgut membranes. | site-directed mutagenesis was used to examine the role of predicted loops 2 (374qpwp377) and 3 (436qrsgtpf442) in domain ii of the bacillus thuringiensis cry1c delta endotoxin for insecticidal specificity and receptor binding. q374e, s438f, and g439a substitutions resulted in near or complete loss of toxicity toward both spodoptera littoralis and aedes aegypti. r437k, r437i, and g439v mutants exhibited significantly reduced toxicity to s. littoralis and a. aegypti, while mutations of t440, p441, ... | 1999 | 10398834 |
| two novel delta-endotoxin gene families cry26 and cry28 from bacillus thuringiensis ssp. finitimus. | genes cry26aal and cry28aal were cloned from bacillus thuringiensis ssp. finitimus strain b-1166 vkpm. this strain forms insecticidal crystal bodies either outside or inside the exosporium. the deduced amino acid sequence of the cry26aal gene product included seven residues determined to be an n-terminal part of a chymotrypsin-treated delta-endotoxin isolated from the same strain. earlier this protein was detected in both free and spore-associated types of crystals [revina et al., biokhimia (199 ... | 1999 | 10403372 |
| cloning and complete sequence characterization of two gypsy moth aminopeptidase-n cdnas, including the receptor for bacillus thuringiensis cry1ac toxin. | the complete cdnas corresponding to two distinct gypsy moth (lymantria dispar) larval gut aminopeptidases, apn1 and lambda apn2, were cloned and sequenced. the 3.4 kilobasepair cdna of apn1 which encodes a 1017 amino acid prepro-protein corresponds to the previously-identified gypsy moth apn (apn-1) that specifically binds the cry1ac delta-endotoxin of bacillus thuringiensis. analysis of the primary structure of apn1 revealed a cluster of five potential n-linked glycosylation sites near the n-te ... | 1999 | 10406091 |
| monarch bt-corn paper questioned. | 1999 | 10409342 | |
| genetic mapping of resistance to bacillus thuringiensis toxins in diamondback moth using biphasic linkage analysis. | transgenic plants producing environmentally benign bacillus thuringiensis (bt) toxins are deployed increasingly for insect control, but their efficacy will be short-lived if pests adapt quickly. the diamondback moth (plutella xylostella), a worldwide pest of vegetables, is the first insect to evolve resistance to bt toxins in open-field populations. a recessive autosomal gene confers resistance to at least four bt toxins and enables survival without adverse effects on transgenic plants. allelic ... | 1999 | 10411882 |
| florida's salt-marsh management issues: 1991-98. | during the 1990s, florida has continued to make important strides in managing salt marshes for both mosquito control and natural resource enhancement. the political mechanism for this progress continues to be interagency cooperation through the florida coordinating council on mosquito control and its subcommittee on managed marshes (somm). continuing management experience and research has helped refine the most environmentally acceptable source reduction methods, which typically are rotational i ... | 1999 | 10412113 |
| towards management of mosquitoes at homebush bay, sydney, australia. i. seasonal activity and relative abundance of adults of aedes vigilax, culex sitiens, and other salt-marsh species, 1993-94 through 1997-98. | the mosquitoes associated with 2 saline wetlands at homebush bay, sydney, australia, were investigated over 5 consecutive seasons. twenty-one species were collected in adult traps at the 2 sites but the saline wetlands supported larvae of only 4 species: aedes alternans, aedes camptorhynchus, aedes vigilax, and culex sitiens. of these, ae. vigilax and cx. sitiens were the most common, and their peak abundances generally occurred during february and april, respectively. both wetlands were influen ... | 1999 | 10412120 |
| detection of genetic polymorphism by rapd-pcr among isolates of bacillus thuringiensis. | sixteen isolates of bacillus thuringiensis recovered from different jordanian habitats were compared using random amplification of polymorphic dna (rapd) to determine whether they could be differentiated at the molecular level. total genomic dna from each isolate and three reference strains were amplified using 10-mer primers. electrophoretic analysis of the amplification products revealed the incidence of polymorphism among the isolates. pair-wise comparisons of polymorphic products were used t ... | 1999 | 10423743 |
| [effect of pesticides on bacillus thuringiensis strains under controlled conditions]. | little is known about native populations of bacillus thuringiensis (bt) isolated from soils of argentina. we undertook this study to determine the resistance to different pesticides of two commercial and fourteen native strains of bt under in vitro conditions. an agar plate bioassay test conducted with ten pesticides and sixteen strains of bt showed that basagran, scepter, fungoxan and decis were not toxic for the bioinsecticide bacteria at recommended application rates (rar). in contrast, low c ... | 1999 | 10425660 |
| activation process of dipteran-specific insecticidal protein produced by bacillus thuringiensis subsp. israelensis. | dipteran-specific insecticidal protein cry4a is produced as a protoxin of 130 kda in bacillus thuringiensis subsp. israelensis. here we performed the in vitro processing of cry4a and showed that the 130-kda protoxin of cry4a was processed into the two protease-resistant fragments of 20 and 45 kda through the intramolecular cleavage of a 60-kda intermediate. the processing into these two fragments was also observed in vivo. to investigate functional properties of the two fragments, gst (glutathio ... | 1999 | 10427035 |
| multiplex pcr screening to detect cry9 genes in bacillus thuringiensis strains. | an extended pcr method was established to rapidly identify and classify bacillus thuringiensis strains containing cry (crystal protein) genes toxic to lepidopteran, coleopteran, and dipteran pests (ben-dov et al., appl. environ. microbiol. 63:4883-4890, 1997). to optimize identification of all reported cry genes, this methodology needs a complete pcr set of primers. in the study reported here, a set of universal (un9) and specific primers for multiplex rapid screening for all four known genes fr ... | 1999 | 10427071 |
| efficacy of new formulations of the microbial larvicide bacillus sphaericus against polluted water mosquitoes in thailand. | two new water dispersible granular (wdg) formulations of the microbial control agent bacillus sphaericus (strain 2362) were extensively evaluated in polluted waters against culex quinquefasciatus in thailand. the studies were carried out in stagnant as well as flowing waters during august 1997 to july 1998. the trial period covered both rainy and dry seasons. the two wdg formulations of b. sphaericus tested were low potency (350 itu/mg) and high potency (630 itu/mg) products. both formulations w ... | 1999 | 10436884 |
| functional insights into pgi2, a cryptic rolling-circle replicating plasmid from bacillus thuringiensis. | detailed functional analysis revealed the modular organization of pgi2, a 9672 bp plasmid from bacillus thuringiensis h1.1 that harbours the 4149 bp transposon tn4430. whereas the pgi2 leading-strand replicon was identified through deletion experiments, sequence comparisons indicated the presence of an ssot-like single-strand origin commonly found among bacillus plasmids. southern hybridization confirmed the existence of ssdna intermediates, but only in the case of plasmid derivatives lacking th ... | 1999 | 10439392 |
| 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 |