Search results for "Bacillus thuringiensis"
showing 10 items of 211 documents
Unraveling the Composition of Insecticidal Crystal Proteins in Bacillus thuringiensis: a Proteomics Approach.
2020
ABSTRACT Bacillus thuringiensis (Bt) is the most widely used active ingredient for biological insecticides. The composition of δ-endotoxins (Cry and Cyt proteins) in the parasporal crystal determines the toxicity profile of each Bt strain. However, a reliable method for their identification and quantification has not been available, due to the high sequence identity of the genes that encode the δ-endotoxins and the toxins themselves. Here, we have developed an accurate and reproducible mass spectrometry-based method (liquid chromatography-tandem mass spectrometry-multiple reaction monitoring [LC-MS/MS-MRM]) using isotopically labeled proteotypic peptides for each protein in a particular mix…
Bacillus thuringiensis treatment modulate the HSP70 expression in larva and adult brain of Rhynchophorus ferrugineus
2013
To study the pathogen-host relationship, we used the model of the entomopathogenic bacterium Bacillus thuringiensis (Bt) and Rhynchophorus ferrugineus, a quarantine pest that attacks palm trees. In particular, we focused on the Bt stress-induced infections. We studied the effect of Bt on larval and adult growth, and on the expression of the heat shock proteins (HSPs), rapidly synthesized in the cell after exposure to stress including pathogens. Bt has negative effects on larval and adult growth, on total hemocytes counts and on the hemocyte type. HSP70 was evaluated in the supernatant of the brain lysate obtained from larvae and adults fed with sublethal doses of Bt. HSP70 expression was mo…
Unveiling gene expression regulation of the Bacillus thuringiensis Cry3Aa toxin receptor ADAM10 by the potato dietary miR171c in Colorado potato beet…
2021
Background The Colorado potato beetle (CPB) is a worldwide devastating pest of potato plants and other Solanaceae characterized by its remarkable ability to evolve resistance to insecticides. Bacillus thuringiensis (Bt) Cry3Aa toxin represents an environmentally-safe alternative for CPB control but larvae susceptibility to this toxin has been reported to vary depending on the host plant on which larvae feed. To gain more insight into how nutrition mediates Bt tolerance through effects on gene expression here we explored the post-transcriptional regulation by miRNAs of the CPB-ADAM10 gene encoding the Cry3Aa toxin functional receptor ADAM10. Results The lower CPB-ADAM10 gene expression in CP…
Comprehensive Analysis of Gene Expression Profiles of the Beet Armyworm Spodoptera exigua Larvae Challenged with Bacillus thuringiensis Vip3Aa Toxin
2013
Made available in DSpace on 2014-12-03T13:11:48Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-12-02Bitstream added on 2014-12-03T13:22:24Z : No. of bitstreams: 1 WOS000327944500105.pdf: 2100332 bytes, checksum: 71ea7616e9a7949eed19cff4ce56111f (MD5) Spanish Ministerio de Ciencia e Innovacion European FEDER funds Generalitat Valenciana Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Host-pathogen interactions result in complex relationship, many aspects of which are not completely understood. Vip proteins, which are Bacillus thuringensis (Bt) insecticidal toxins produced during the vegetative stage, are selectively effective against specific insect pests. This ne…
Correlation between serovars of Bacillus thuringiensis and type I beta-exotoxin production.
2003
beta-Exotoxin is a thermostable metabolite produced by some strains of Bacillus thuringiensis. Because of vertebrate toxicity, most commercial preparations of B. thuringiensis are prepared from isolates that do not produce beta-exotoxin. The aim of the present study was to find out the possible relationship between serovars of B. thuringiensis and beta-exotoxin production. A specific HPLC assay for type I beta-exotoxin has been used to detect this exotoxin in supernatants from final whole cultures of 100 strains belonging to four serovars of B. thuringiensis: thuringiensis, kurstaki, aizawai, and morrisoni. For each serovar, 25 strains randomly chosen from two Spanish collections were analy…
Distribution of cryl, cryll and cryV Genes within Bacillus thuringiensis Isolates from Spain
1999
Summary Using a PCR-based approach, a collection of 223 isolates of Bacillus thuringiensis from Spain was screened for the presence of cry genes belonging to three families. Genes from the cryI , cryII and cryV families were found in 54%, 42%, and 66% of the isolates, respectively. Only 23% of the isolates did not show the presence of any of the genes tested. Frequencies of these genes were compared in isolates from soil samples and from samples of cereal stores and mills, being this higher in the latter. Specific primers were used to detect cryIA(a), cryIA(b), cryIA(c), cryIA(d), cryIA(e), cryIB, cryIC, cryID, cryIE, cryIF and cryIG genes. Within the cryI family, the most frequent gene was…
Identification and characterization of the new Bacillus thuringiensis serovars pirenaica (serotype H57) and iberica (serotype H59)
1999
Two new Bacillus thuringiensis strains have been classified by the H antigen of the cells and differentiated by their morphological, biochemical and molecular characteristics. The flagellar agglutination showed that both strains bore specific H antigens which allowed their classification as the new serotypes H57 and H59. The serovar names proposed for the type strains characterized in this work are B. thuringiensis ser. pirenaica, for the H serotype 57, and B. thuringiensis ser. iberica, for the H serotype 59. Further characterization of these strains, by means of SDS-PAGE, Western inmunodetection, plasmid profile and cry-gene identification by polymerase chain reaction, confirmed the origi…
Characterization ofBacillus thuringiensisserovarbolivia(serotype H63), a novel serovar isolated from the Bolivian high valleys
1999
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 showed positive reaction for Cry1 E, Cry3 A, Cry4 A and Cry11 A crystal proteins. The plasmid pattern revealed two large and two small plasmids. Toxicity tests were performed against 14 insects and a…
Environmental distribution and diversity of Bacillus thuringiensis in Spain.
1998
Bacillus thuringiensis was isolated from 301 out of 1,005 samples collected in Spain from agricultural and non-cultivated soils, dust from stored products, and dead insects. Based on the production of parasporal crystals, 1,401 isolates were identified as B. thuringiensis after examining 11,982 B. thuringiensis-like colonies. We found a greater presence of B. thuringiensis in dust from grain storages than in other habitats. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the spore-crystal mixtures revealed diverse populations of B. thuringiensis which were differentiated in at least 92 distinct protein profiles. Serological identification also showed great diversity among the S…
Characterization of Bacillus thuringiensis ser. balearica (Serotype H48) and ser. navarrensis (serotype H50): two novel serovars isolated in Spain.
2000
The novel strains of Bacillus thuringiensis PM9 and NA69, isolated from soil samples in Spain, were classified and characterized in terms of their crystal proteins, plasmid profile, cry genes content, and their toxicological properties against several species of Lepidoptera, Coleoptera, and Diptera. Both strains share morphological and biochemical characteristics with previously described B. thuringiensis strains, although their unique H antigens identify them as two new serotypes. Two new serovar names, B. thuringiensis serovar balearica (H serotype 48) and B. thuringiensis serovar navarrensis (H serotype 50) are proposed for the type strains PM9 and NA69, respectively.