Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
|---|
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| [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 |
| 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 |
| 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 |
| 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 |
| 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 |
| monarch bt-corn paper questioned. | 1999 | 10409342 | |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| agricultural biotechnology. | 1999 | 10385330 | |
| bt resistance plan appraised. | 1999 | 10385310 | |
| 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 |
| 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 |
| [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 |
| 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 |
| 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 |
| time for a fresh look at the bacterial chromosome. | 1999 | 10366858 | |
| 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 |
| 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 |
| 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 |
| 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 |
| trade concerns dominate gm debate in us. | 1999 | 10360556 | |
| 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 |
| bacillus thuringiensis cry1ac protoxin is a potent systemic and mucosal adjuvant. | recently we demonstrated that recombinant cry1ac protoxin from bacillus thuringiensis is a potent systemic and mucosal immunogen. in this study we compared the adjuvant effects of cry1ac and cholera toxin (ct) for the hepatitis b surface antigen (hbsag) and bovine serum albumin (bsa). the antibody responses of intestinal secretions and serum were determined by elisa in balb/c mice immunized through the intragastric (ig) or intraperitoneal (ip) routes. when hbsag was administered via ig, the anti ... | 1999 | 10354369 |
| intragastric and intraperitoneal administration of cry1ac protoxin from bacillus thuringiensis induces systemic and mucosal antibody responses in mice. | the spore-forming soil bacterium bacillus thuringiensis produces parasporal inclusion bodies composed by delta-endotoxins also known as cry proteins, whose resistance to proteolysis, stability in highly alkaline ph and innocuity to vertebrates make them an interesting candidate to carrier of relevant epitopes in vaccines. the purpose of this study was to determine the mucosal and systemic immunogenicity in mice of cry1ac protoxin from b. thuringiensis hd73. crystalline and soluble forms of the p ... | 1999 | 10353588 |
| transgenic pollen harms monarch larvae. | 1999 | 10353241 | |
| aggregation of bacillus thuringiensis cry1a toxins upon binding to target insect larval midgut vesicles | during sporulation, bacillus thuringiensis produces crystalline inclusions comprised of a mixture of delta-endotoxins. following ingestion by insect larvae, these inclusion proteins are solubilized, and the protoxins are converted to toxins. these bind specifically to receptors on the surfaces of midgut apical cells and are then incorporated into the membrane to form ion channels. the steps required for toxin insertion into the membrane and possible oligomerization to form a channel have been ex ... | 1999 | 10347034 |
| comparison of isozyme patterns of aedes aegypti populations collected from pre- and post-bacillus thuringiensis israelensis treatment sites in thailand. | isozyme patterns of 13 field-collected populations of aedes aegypti from thailand were compared using starch gel electrophoresis. three populations were collected before the bacillus thuringiensis var. israelensis, (b.t.i.) application was initiated. the other 10 populations were collected after the b.t.i. treatment. results revealed that the number of polymorphic loci were lower in the b.t.i. treated populations as compared to controls. in addition, lower genetic variability was found in popula ... | 1999 | 10342268 |
| 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 |
| 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 |
| 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 |
| epa biotech rule reviewed yet again. | 1999 | 10331783 | |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| transition state of the rate-limiting step of heat denaturation of cry3a delta-endotoxin. | heat denaturation of cry3a delta-endotoxin from bacillus thuringiensis var. tenebrionis and its 55 kda fragment was studied by differential scanning microcalorimetry at low ph. analysis of the calorimetric data has shown that denaturation of cry3a delta-endotoxin is a nonequilibrium process at heating rates from 0. 125 to 2 k/min. this means that the stability of delta-endotoxin (the apparent temperature of denaturation tm) under these conditions is under kinetic control rather than under thermo ... | 1999 | 10194327 |
| cloning and nucleotide sequence analysis of gyrb of bacillus cereus, b. thuringiensis, b. mycoides, and b. anthracis and their application to the detection of b. cereus in rice. | as 16s rrna sequence analysis has proven inadequate for the differentiation of bacillus cereus from closely related species, we employed the gyrase b gene (gyrb) as a molecular diagnostic marker. the gyrb genes of b. cereus jcm 2152(t), bacillus thuringiensis iam 12077(t), bacillus mycoides atcc 6462(t), and bacillus anthracis pasteur #2h were cloned and sequenced. oligonucleotide pcr primer sets were designed from within gyrb sequences of the respective bacteria for the specific amplification a ... | 1999 | 10103241 |
| integrative model for binding of bacillus thuringiensis toxins in susceptible and resistant larvae of the diamondback moth (plutella xylostella). | insecticidal crystal proteins from bacillus thuringiensis in sprays and transgenic crops are extremely useful for environmentally sound pest management, but their long-term efficacy is threatened by evolution of resistance by target pests. the diamondback moth (plutella xylostella) is the first insect to evolve resistance to b. thuringiensis in open-field populations. the only known mechanism of resistance to b. thuringiensis in the diamondback moth is reduced binding of toxin to midgut binding ... | 1999 | 10103230 |
| kinetic modeling of omega-transamination for enzymatic kinetic resolution of alpha-methylbenzylamine. | a kinetic model for omega-transaminase from bacillus thuringiensis js64 was developed by using the king-altman method to simulate the kinetic resolution of alpha-methylbenzylamine (alpha-mba). starting from a ping-pong bi-bi mechanism, a complete kinetic model including substrate inhibition only in the reverse reaction (i.e., transamination between acetophenone and l-alanine) was developed. the asymmetric synthesis of (s)-alpha-mba proved to be difficult due to a much lower maximum reverse react ... | 1998 | 10099461 |
| isolation and detection of listeria monocytogenes using fluorogenic and chromogenic substrates for phosphatidylinositol-specific phospholipase c. | the bcm listeria monocytogenes detection system (lmds) consists of a selective preenrichment broth (lmpeb), selective enrichment broth (lmseb), selective/differential plating medium (lmpm), and identification on a confirmatory plating medium (lmcm). the efficacy of the bcm lmds was determined using pure cultures and naturally and artificially contaminated environmental sponges. the bcm lmpeb allowed the growth of listeria and resuscitation of heat-injured l. monocytogenes. the bcm lmseb, which c ... | 1999 | 10090243 |
| bacterial control of mosquito larvae: investigation of stability of bacillus thuringiensis var. israelensis and bacillus sphaericus standard powders. | bacillus thuringiensis var. israelensis and bacillus sphaericus products were assayed against their respective reference powders ips82 and sph88. since their production in 1982 and 1988, the potency and larvicidal activity of these standard powders have been regularly checked on their test insects aedes aegypti (for ips82) or culex pipiens (for sph88). over the 16-year evaluation period of ips82 and 10-year evaluation period of sph88, their potencies were considered stable. the global mean of ea ... | 1998 | 10084145 |
| acute toxicity of selected pesticides to the pacific blue-eye, pseudomugil signifer (pisces). | because the larvivorous fish pseudomugil signifer is native to southeastern queensland and is abundant in shallow estuarine habitats, intertidal marshes, wetland habitats, and freshwater streams, it was chosen as an indicator species for toxicologic studies with pesticides. acute toxicity studies with 2 organophosphorus pesticides (pirimiphos-methyl and temephos) and 3 alternate compounds under evaluation for registration in australia (bacillus thuringiensis var. israelensis, s-methoprene, and p ... | 1998 | 10084142 |
| field trials of biolarvicide bacillus thuringiensis var. israelensis strain 164 and the larvivorous fish aplocheilus blocki against anopheles stephensi for malaria control in goa, india. | severe outbreaks of malaria occurred in the coastal villages of the candolim primary health centre (phc) of goa, india, in 1993 and 1994. these outbreaks were associated with accelerated construction activity with an influx of migrant laborers. the weekly application of bacillus thuringiensis var. israelensis (b.t.i.) strain 164 at 1 g/m2 and introduction of the indigenous larvivorous fish aplocheilus blocki in major breeding habitats of anopheles stephensi replaced ongoing ddt spraying and pyre ... | 1998 | 10084141 |
| efficient expression of mosquito-larvicidal proteins in a gram-negative bacterium capable of recolonization in the guts of anopheles dirus larva. | the gram-negative bacterium, an11/2 g1, isolated from the guts of anopheles dirus mosquito larvae, was identified as enterobacter amnigenus. the e. amnigenus was able to recolonize in the gut of an. dirus larva but not in those of aedes aegypti and culex quinquefasciatus larvae. it was able to float in water for a longer period than bacillus thuringiensis subsp. israelensis and bacillus sphaericus. these are desirable characteristics for a delivery vehicle of mosquito-larvicidal toxins for the c ... | 1999 | 10077823 |
| specific binding of the e2 subunit of pyruvate dehydrogenase to the upstream region of bacillus thuringiensis protoxin genes. | during sporulation, bacillus thuringiensis produces inclusions comprised of different amounts of several related protoxins, each with a unique specificity profile for insect larvae. a major class of these genes designated cry1 have virtually identical dual overlapping promoters, but the upstream sequences differ. a gel retardation assay was used to purify a potential regulatory protein which bound with different affinities to these sequences in three cry1 genes. it was identified as the e2 subun ... | 1999 | 10075684 |
| experimental formulations of bacillus sphaericus and b. thuringiensis israelensis against culex quinquefasciatus and anopheles gambiae (diptera: culicidae) in burkina faso. | efficacies of locally produced, sustained release granular formulations of bacillus sphaericus (bs) strain 2362 and b. thuringiensis israelensis (bti) were compared with commercial liquid concentrates of the same bacteria in cesspits and rain-filled puddles in ouagadougou, burkina faso. duration of control was dependent on the product, the transient nature of some sites, and the target mosquito larvae. bs granules applied at the rate of 3.0 g/m2 (30 kg/ha) reduced culex quinquefasciatus say 99% ... | 1999 | 10071494 |
| characterization of the mbl determinant and cloning of the spoiiid gene from bacillus cereus atcc 10987. | to examine the transcriptional start site of the putative bacillus cereus mbl gene, we have cloned and sequenced the upstream region of the previously reported b. cereus mbl determinant, which showed sequence similarity to the mreb morphogene from escherichia coli. primer extension analysis revealed the transcriptional start site of mbl to 259 bp upstream of the putative translational start site and showed that the mbl gene was expressed at 3, 6, and 10 h of growth after inoculation. antibodies ... | 1999 | 10069858 |
| us groups sue over approval of bt crops...as uk press reports come under fire. | 1999 | 10067881 | |
| overexpression of the bacillus thuringiensis (bt) cry2aa2 protein in chloroplasts confers resistance to plants against susceptible and bt-resistant insects. | evolving levels of resistance in insects to the bioinsecticide bacillus thuringiensis (bt) can be dramatically reduced through the genetic engineering of chloroplasts in plants. when transgenic tobacco leaves expressing cry2aa2 protoxin in chloroplasts were fed to susceptible, cry1a-resistant (20,000- to 40,000-fold) and cry2aa2-resistant (330- to 393-fold) tobacco budworm heliothis virescens, cotton bollworm helicoverpa zea, and the beet armyworm spodoptera exigua, 100% mortality was observed a ... | 1999 | 10051556 |
| a randomly amplified polymorphic dna marker specific for the bacillus cereus group is diagnostic for bacillus anthracis. | aiming to develop a dna marker specific for bacillus anthracis and able to discriminate this species from bacillus cereus, bacillus thuringiensis, and bacillus mycoides, we applied the randomly amplified polymorphic dna (rapd) fingerprinting technique to a collection of 101 strains of the genus bacillus, including 61 strains of the b. cereus group. an 838-bp rapd marker (sg-850) specific for b. cereus, b. thuringiensis, b. anthracis, and b. mycoides was identified. this fragment included a putat ... | 1999 | 10049896 |
| evaluation of transgenic sweet corn hybrids expressing cryia (b) toxin for resistance to corn earworm and fall armyworm (lepidoptera: noctuidae). | many of the lepidopterous insects which attack sweet corn, zea mays l., are susceptible to insecticidal proteins produced by bacillus thuringiensis ssp. kurstaki (berliner) (btk). transgenic sweet corn expressing a synthetic cry gene for production of a btk-insecticidal protein may provide a more environmentally acceptable means of sweet corn production. eight transgenic sweet corn hybrids containing a synthetic gene for cryia(b) protein production (bt11 event) were evaluated for resistance to t ... | 1999 | 10036986 |
| domain iii of the bacillus thuringiensis delta-endotoxin cry1ac is involved in binding to manduca sexta brush border membranes and to its purified aminopeptidase n. | three types of binding assays were used to study the binding of bacillus thuringiensis delta-endotoxin cry1ac to brush border membrane vesicle (bbmv) membranes and a purified putative receptor of the target insect manduca sexta. using hybrid proteins consisting of cry1ac and the related cry1c protein, it was shown that domain iii of cry1ac is involved in specificity of binding as observed by all three techniques. in ligand blotting experiments using sds-page-separated bbmv proteins as well as th ... | 1999 | 10027964 |
| 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 |
| the oligomeric state of bacillus thuringiensis cry toxins in solution. | the molecular mass of different cry toxins produced by bacillus thuringiensis bacteria was estimated by size-exclusion chromatography and non-denaturing polyacrylamide gel electrophoresis at neutral and alkaline ph in order to assess the existence of oligomers in solution. we found that cry1aa, cry1ac, cry1c, cry1d and cry3a toxins exist in solution as a mixture of monomer and high molecular mass aggregates with an apparent molecular mass greater than 600 kda, that depend on the time elapsed bet ... | 1999 | 9989219 |
| cdna cloning and expression of bacillus thuringiensis cry1aa toxin binding 120 kda aminopeptidase n from bombyx mori. | bacillus thuringiensis cry1aa toxin binds to a 120 kda putative receptor protein in the bombyx mori midgut. recently, this protein was purified and identified as glycosyl-phosphatidylinositol (gpi) anchored aminopeptidase n (apn). in this study, a full-length cdna thought to encode this 120 kda apn was isolated and sequenced. it has a 2958 bp orf encoding 986 amino acids. in the deduced amino acid sequence, we identified gpi-anchor and zinc-metallopeptidase signals, which are the same as those o ... | 1999 | 9931470 |
| biochemical characterization of bacillus thuringiensis cytolytic toxins in association with a phospholipid bilayer. | the interaction of two bacillus thuringiensis cytolytic toxins, cyta and cytb, with a phospholipid bilayer and their structure in the membrane-bound state were investigated by proteolysis using phospholipid vesicles as a model system. a toxin conformational change upon membrane binding was detected by comparing the proteolytic profile of membrane-bound toxin and saline-solubilized toxin. when membrane-bound toxin was exposed to protease k or trypsin, novel cleavage sites were found between the a ... | 1999 | 9931315 |
| toxicity, binding, and permeability analyses of four bacillus thuringiensis cry1 delta-endotoxins using brush border membrane vesicles of spodoptera exigua and spodoptera frugiperda. | the binding and pore formation properties of four bacillus thuringiensis cry1 toxins were analyzed by using brush border membrane vesicles from spodoptera exigua and spodoptera frugiperda, and the results were compared to the results of toxicity bioassays. cry1fa was highly toxic and cry1ac was nontoxic to s. exigua and s. frugiperda larvae, while cry1ca was highly toxic to s. exigua and weakly toxic to s. frugiperda. in contrast, cry1bb was active against s. frugiperda but only marginally activ ... | 1999 | 9925568 |
| introduction and expression of the cry1ac gene of bacillus thuringiensis in a cereal-associated bacterium, bacillus polymyxa. | the abilities of bacillus polymyxa and bacillus thuringiensis to survive on the rice phyllospere were compared; it was found that b. polymyxa colonizes the crop better. this study also showed that b. polymyxa inoculation to rice plants increased the shoot and the root growth of the crop. efforts were made to introduce the cry1ac gene of b. thuringiensis subsp. kurstaki into b. polymyxa so that the application of such transgenic b. polymyxa strains would prove to be dually beneficial to rice crop ... | 1999 | 9922467 |
| 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 |
| 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 |
| 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 |
| 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 |
| toxicity and receptor binding properties of a bacillus thuringiensis cryic toxin active against both lepidoptera and diptera. | this study describes an investigation into the relationship among toxicity, specificity, and binding of cryic delta-endotoxin from bacillus thuringiensis subspecies aizawai hd-229. in vivo bioassays of larvae using inclusions (aedes aegypti) or solubilized toxin (spodoptera littoralis, spodoptera exigua, spodoptera frugiperda, and manduca sexta) revealed that cryic was toxic to both dipteran and lepidopteran larvae. in vitro saturation binding assays with cryic toxin labeled in vivo with [35s]me ... | 1999 | 9878290 |
| isolation and characterization of brush border membrane vesicles from whole aedes aegypti larvae. | studies of the binding interactions of dipteran-specific bacillus thuringiensis delta-endotoxins are hindered by the lengthy midgut dissection procedure needed for preparation of brush border membrane vesicles. in an attempt to resolve this problem, brush border membrane vesicles were isolated from homogenates of whole aedes aegypti larvae by a modification of the method of macintosh et al. (1994). these preparations were found to resolve well on sds-page and appeared as spherical vesicles of va ... | 1999 | 9878289 |
| 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 |
| conjugation in gram-positive bacteria and kinetics of plasmid transfer. | 1998 | 9850682 | |
| 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 |
| a holistic approach for determining the entomopathogenic potential of bacillus thuringiensis strains. | the cry gene content of bacillus thuringiensis subsp. aizawai hd-133 was analyzed by a combination of high-pressure liquid chromatography (hplc) and exclusive pcr. a total of six cry genes were detected in genomic dna purified from hd-133, four from the cry1 family (cry1aa, cry1ab, cry1c, and cry1d) as well as a gene each from the cry2 (cry2b) and the cry1i families. to directly determine which genes were expressed and crystallized in the purified parasporal inclusions, solubilized and trypsiniz ... | 1998 | 9835562 |
| effect of canavanine from alfalfa seeds on the population biology of bacillus cereus | bacillus cereus uw85 suppresses diseases of alfalfa seedlings, although alfalfa seed exudate inhibits the growth of uw85 in culture (j. l. milner, s. j. raffel, b. j. lethbridge, and j. handelsman, appl. microbiol. biotechnol. 43:685-691, 1995). in this study, we determined the chemical basis for and biological role of the inhibitory activity. all of the alfalfa germ plasm tested included seeds that released inhibitory material. we purified the inhibitory material from one alfalfa cultivar and i ... | 1998 | 9835549 |
| learning from past experience. | 1998 | 9831013 | |
| bacillus weihenstephanensis sp. nov. is a new psychrotolerant species of the bacillus cereus group. | the bacillus cereus group comprises the four valid species bacillus cereus, bacillus mycoides, bacillus thuringiensis and bacillus anthracis. some isolates of b. cereus are known to be psychrotolerant (growth at 7 degrees c or below). here, specific sequence differences are described between the 16s rdna, the 23s rdna, the 16s-23s rdna spacer region and the genes of the major cold-shock protein homologue cspa in a variety of psychrotolerant and mesophilic b. cereus and b. mycoides strains. rando ... | 1998 | 9828439 |
| modulation of cry iv a toxin protein expression by glucose in bacillus thuringiensis israelensis. | bacillus thuringiensis subsp. israelensis (bti) produces cry iv a protoxin protein as part of the insecticidal crystal toxin during sporulation. this study was conducted with the objective of identifying environmental signals which regulate toxin synthesis by bti. glucose was found to repress cry iv a toxin induction at the mrna level. the repressive effect of glucose was dependent on a phosphorylation step since protein kinase inhibitor calphostin c relieved the 130-kd protoxin synthesis at bot ... | 1998 | 9826542 |
| the poultry red mite dermanyssus gallinae (de geer, 1778): current situation and future prospects for control. | the current importance of dermanyssus gallinae, mainly in egg layer, in europe is pointed out. the limits of conventional control methods are underlined (development of mite resistance--future insecticide legislation and animal welfare legislation). alternative control methods such as feeding deterrents or biological control, are reviewed in the context of poultry pest management. | 1998 | 9823064 |
| nonessential activation and competitive inhibition of bacterial phosphatidylinositol-specific phospholipase c by short-chain phospholipids and analogues. | phosphatidylinositol-specific phospholipase c (pi-plc) from bacillus thuringiensis is an allosteric enzyme with both a phospholipid activator site and an active site. the activation of pi-plc enzyme is optimal with phosphatidylcholine (pc) binding to the activator site and anchoring the enzyme to the interface [zhou, c., et al. (1997) biochemistry 36, 347-355; zhou, c., et al. (1997) biochemistry 36, 10089-10091]. in contrast to pc, anionic short-chain phospholipids with smaller headgroups [phos ... | 1998 | 9819236 |
| potency of products based on bacillus thuringiensis var. israelensis: interlaboratory variations. | six quality-control laboratories in 4 countries independently bioassayed aliquots of a flowable formulation of bacillus thuringiensis var. israelensis (b.t.i.) against the international standard powder ips-82. all laboratories substantially followed world health organization or u.s. department of agriculture standard protocols. significant differences were found in resulting potency values between laboratories. factors that may have influenced results, such as age, stage, and strain of larvae us ... | 1998 | 9813828 |
| assignment of delta-endotoxin genes of the four lepidoptera-specific bacillus thuringiensis strains that produce spherical parasporal inclusions. | unique strains of bacillus thuringiensis, that belong to the four h serogroups (serovar sumiyoshiensis, serovar fukuokaensis, serovar darmstadiensis, and serovar japonensis) and produce spherical parasporal inclusions specifically toxic to lepidopteran larvae, were examined for comparative analysis of the genes encoding delta-endotoxin proteins. gene analysis revealed that there is no difference between the four strains in nucleotide sequences of the 1, 937-bp dna segment covering the four conse ... | 1998 | 9806979 |
| suppression of diamondback moth (lepidoptera: plutellidae) with an entomopathogenic nematode (rhabditida: steinernematidae) and bacillus thuringiensis berliner. | we tested the efficacy of the all strain of steinernema carpocapsae (weiser) against larvae of the diamondback moth, plutella xylostella (l.). in laboratory bioassays we found that (1) commercially formulated nematodes produced in vitro were as effective as nematodes produced in vivo, (2) resistance of p. xylostella to bacillus thuringiensis berliner subsp. kurstaki did not confer cross-resistance to nematodes, (3) mortality caused by nematodes was higher for early than late 3rd-instar p. xylost ... | 1998 | 9805498 |
| cyt1aa protein of bacillus thuringiensis is toxic to the cottonwood leaf beetle, chrysomela scripta, and suppresses high levels of resistance to cry3aa | the insecticidal activity of bacillus thuringiensis is due primarily to cry and cyt proteins. cry proteins are typically toxic to lepidopterous, coleopterous, or dipterous insects, whereas the known toxicity of cyt proteins is limited to dipterans. we report here that a cyt protein, cyt1aa, is also highly toxic to the cottonwood leaf beetle, chrysomela scripta, with a median lethal concentration of 2.5 ng/mm2 of leaf surface for second-instar larvae. additionally, we show that cyt1aa suppresses ... | 1998 | 9797292 |
| variable cross-resistance to cry11b from bacillus thuringiensis subsp. jegathesan in culex quinquefasciatus (diptera: culicidae) resistant to single or multiple toxins of bacillus thuringiensis subsp. israelensis. | a novel mosquitocidal bacterium, bacillus thuringiensis subsp. jegathesan, and one of its toxins, cry11b, in a recombinant b. thuringiensis strain were evaluated for cross-resistance with strains of the mosquito culex quinquefasciatus that are resistant to single and multiple toxins of bacillus thuringiensis subsp. israelensis. the levels of cross-resistance (resistance ratios [rr]) at concentrations which caused 95% mortality (lc95) between b. thuringiensis subsp. jegathesan and the different b ... | 1998 | 9797262 |
| influence of ph on the toxicity and survival of total cells and spores of bacillus thuringiensis. | b. thuringiensis (bt) is one of the most important microorganism among those studied because of their entomopathogenic potential against insect plagues and vectors. in this work, the pathogenicity and survival of total cells and spores of three autochthonous strains of b. thuringiensis isolated from argentine soils (a61, a27 and a68) and the commercial strain hd-1 were studied at different ion hidrogen concentrations (ph = 4.4; 5.4; 7.4; 8.4; 9.4 and 10.4) under laboratory conditions. the greate ... | 1998 | 9793141 |