scholarly journals Correspondence of High Levels of Beta-Exotoxin I and the Presence of cry1B in Bacillus thuringiensis

2002 ◽  
Vol 68 (9) ◽  
pp. 4182-4186 ◽  
Author(s):  
Sylvain Espinasse ◽  
Michel Gohar ◽  
Josette Chaufaux ◽  
Christophe Buisson ◽  
Stéphane Perchat ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Insect Species ◽  
Anthonomus Grandis ◽  
Genetic Determinants ◽  
Natural Isolates ◽  
Culture Supernatants

ABSTRACT Examination of 640 natural isolates of Bacillus thuringiensis showed that the 58 strains (9%) whose supernatants were toxic to Anthonomus grandis (Coleoptera: Curculionidae) produced between 10 and 175 μg of β-exotoxin I per ml. We also found that 55 (46%) of a sample of 118 strains whose culture supernatants were not toxic to A. grandis nevertheless produced between 2 and 5 μg/ml. However, these amounts of β-exotoxin I were below the threshold for detectable toxicity against this insect species. Secretion of large amounts of β-exotoxin I was strongly associated with the presence of cry1B and vip2 genes in the 640 natural B. thuringiensis isolates studied. We concluded that strains carrying cry1B and vip2 genes also possess, on the same plasmid, genetic determinants necessary to promote high levels of production of β-exotoxin I.

SEARCH FOR NATURAL ISOLATES OF Bacillus thuringiensis FOR DEVELOPMENT OF ECOLOGICALLY FRIENDLY BIOLOGICALS

2018 ◽  
Vol 53 (5) ◽  
pp. 1062-1069
Author(s):  
S.D. Grishechkina ◽  
◽  
V.P. Ermolova ◽  
T.A. Romanova ◽  
A.A. Nizhnikov ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Natural Isolates

scholarly journals The Drosophila melanogaster homologue of the human histo-blood group Pk gene encodes a glycolipid-modifying α1,4-N-acetylgalactosaminyltransferase

2004 ◽  
Vol 382 (1) ◽  
pp. 67-74 ◽  
Author(s):  
Ján MUCHA ◽  
Jiří DOMLATIL ◽  
Günter LOCHNIT ◽  
Dubravko RENDIĆ ◽  
Katharina PASCHINGER ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Bacillus Thuringiensis ◽  
Pichia Pastoris ◽  
Genetic Basis ◽  
Methylation Analysis ◽  
Yeast Pichia Pastoris ◽  
Glycan Receptors ◽  
Cloned Cdna ◽  
Crystal Toxin ◽  
Culture Supernatants

Insects express arthro-series glycosphingolipids, which contain an α1,4-linked GalNAc residue. To determine the genetic basis for this linkage, we cloned a cDNA (CG17223) from Drosophila melanogaster encoding a protein with homology to mammalian α1,4-glycosyltransferases and expressed it in the yeast Pichia pastoris. Culture supernatants from the transformed yeast were found to display a novel UDP-GalNAc:GalNAcβ1,4GlcNAcβ1-R α-N-acetylgalactosaminyltransferase activity when using either a glycolipid, p-nitrophenylglycoside or an N-glycan carrying one or two terminal β-N-acetylgalactosamine residues. NMR and MS in combination with glycosidase digestion and methylation analysis indicate that the cloned cDNA encodes an α1,4-N-acetylgalactosaminyltransferase. We hypothesize that this enzyme and its orthologues in other insects are required for the biosynthesis of the N5a and subsequent members of the arthro-series of glycolipids as well as of N-glycan receptors for Bacillus thuringiensis crystal toxin Cry1Ac.

scholarly journals A gene cluster involved in the biosynthesis of vanchrobactin, a chromosome-encoded siderophore produced by Vibrio anguillarum

Microbiology ◽  
2006 ◽  
Vol 152 (12) ◽  
pp. 3517-3528 ◽  
Author(s):  
Miguel Balado ◽  
Carlos R. Osorio ◽  
Manuel L. Lemos
Keyword(s):  
Gene Cluster ◽  
Vibrio Anguillarum ◽  
No Production ◽  
Genetic Determinants ◽  
Dihydroxybenzoic Acid ◽  
Peptide Synthetase ◽  
Genes Encoding ◽  
In Trans ◽  
Culture Supernatants

Vibrio anguillarum serotype O2 strains produce a catechol siderophore named vanchrobactin, which has been identified as N-[N′-(2,3-dihydroxybenzoyl)-arginyl]-serine. This work describes a chromosomal region that harbours the genetic determinants necessary for the biosynthesis of vanchrobactin. The authors have identified the genes involved in 2,3-dihydroxybenzoic acid (DHBA) biosynthesis (vabA, vabB and vabC) and activation (vabE), and a gene (vabF) encoding a non-ribosomal peptide synthetase, which is putatively involved in the assembly of the siderophore components. Also described are the identification and characterization of genes encoding a putative vanchrobactin exporter (vabS) and a siderophore esterase (vabH). In-frame deletion mutants in vabA, vabB, vabC, vabE, vabF and vabH were impaired for growth under conditions of iron limitation, and the analysis of culture supernatants by chrome azurol-S and cross-feeding assays showed almost no production of siderophores in any of the vabABCEF mutants. In addition, deletion mutations of vabA, vabB and vabC abolished production of DHBA, as assessed by chemical and biological analyses. Complementation of each mutant with the corresponding gene provided in trans confirmed the involvement of this gene cluster in the biosynthesis of DHBA and vanchrobactin in V. anguillarum strain RV22. Based on chemical and genetic data, and on published models for other catechol siderophores, a model for vanchrobactin biosynthesis is proposed.

scholarly journals Insecticidal activity of culture supernatants from Bacillus thuringiensis Berliner strains against Spodoptera frugiperda Smith (Lepidoptera: Noctuidae) larvae

1999 ◽  
Vol 28 (4) ◽  
pp. 675-685 ◽  
Author(s):  
Marliton R. Barreto ◽  
Leandro L. Loguercio ◽  
Fernando H. Valicente ◽  
Edilson Paiva
Keyword(s):  
Bacillus Thuringiensis ◽  
Protein Secretion ◽  
Spodoptera Frugiperda ◽  
Wide Spectrum ◽  
Insect Pest ◽  
Polyacrylamide Gel Electrophoresis ◽  
Fall Armyworm ◽  
Tropical Maize ◽  
Potential Applicability ◽  
Culture Supernatants

Novel vegetative insecticidal proteins (Vips) identified in the supernatant of Bacillus thuringiensis (B.t.) cultures have shown to provide adequate control over a wide spectrum of economically important crop pests. To evaluate the potential applicability of these proteins against fall armyworm (Spodoptera frugiperda Smith) larvae, the most important insect pest for tropical maize, the characteristics and mortality effects of culture supernatants from five B.t. strains were investigated. Striking differences among strains were detected, not only in terms of efficiency in killing the insect, but also regarding to mortality effects of heated and non-heated supernatants, which were used to distinguish the heat-sensitive protein-derived insecticidal fraction from a thermostable one, with a non-protein nature (b-exotoxinas). The qualitative, quantitative and temporal patterns of total protein secretion in the medium (supernatant) were assessed through spectrophotometry and polyacrylamide gel electrophoresis. The strains showed remarkably distinct rates of growth and timing for protein secretion relative to cell density in culture. Moreover, the electrophoretic-banding patterns also varied in a strain-specific manner, both in denaturing and non denaturing conditions. Polypeptides displaying a molecular weight that is very close to the expected for previously identified Vip3A proteins were found for the strains with high supernatant-mortality ratios. The data suggest the feasibility and usefulness of searching for protein-derived (Vip-like) insecticidal fractions in B.t. supernatants as a mean of developing especific and efficient alternatives of biological control to be employed in integrated pest management programs of S. frugiperda in tropical maize.

scholarly journals Estirpes de Bacillus thuringiensis efetivas contra insetos das ordens Lepidoptera, Coleoptera e Diptera

2004 ◽  
Vol 39 (1) ◽  
pp. 11-16 ◽  
Author(s):  
Lílian Botelho Praça ◽  
Andréa Cardoso Batista ◽  
Érica Soares Martins ◽  
Claúdia Brod Siqueira ◽  
Daniel Gerheim de Souza Dias ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Aedes Aegypti ◽  
Culex Quinquefasciatus ◽  
Spodoptera Frugiperda ◽  
Anticarsia Gemmatalis ◽  
Anthonomus Grandis ◽  
Lepidoptera Noctuidae

O objetivo deste trabalho foi selecionar entre 300 estirpes de Bacillus thuringiensis as efetivas simultaneamente contra larvas de Spodoptera frugiperda J.E. Smith e Anticarsia gemmatalis Hübner (Lepidoptera: Noctuidae), Anthonomus grandis Boheman (Coleoptera: Curculionidae), Aedes aegypti Linnaeus e Culex quinquefasciatus Say (Diptera: Culicidae). Foram selecionadas duas estirpes de B. thuringiensis, denominadas S234 e S997, que apresentaram atividade contra as três ordens de insetos. As estirpes foram caracterizadas por métodos morfológicos, bioquímicos e moleculares. As mesmas apresentaram duas proteínas principais de 130 e 65 kDa, produtos de reação em cadeia da polimerase de tamanho esperado para a detecção dos genes cry1Aa, cry1Ab, cry1Ac, cry1B e cry2 e cristais bipiramidais, cubóides e esféricos.

Antagonism between Formulations of Different Bacillus thuringiensis Subspecies in Heliothis virescens and Helicoverpa zea (Lepidoptera: Noctuidae)

1998 ◽  
Vol 33 (2) ◽  
pp. 129-135 ◽  
Author(s):  
A. O. Ameen ◽  
J. R. Fuxa ◽  
A. R. Richter
Keyword(s):  
Bacillus Thuringiensis ◽  
Heliothis Virescens ◽  
Helicoverpa Zea ◽  
Insect Species ◽  
Median Lethal Concentrations ◽  
Lepidoptera Noctuidae

Interactions between formulations of the aizawai and kurstaki subspecies of Bacillus thuringiensis Berliner were evaluated by bioassay in Heliothis virescens (F.) and Helicoverpa zea (Boddie). In preliminary experiments, a formulation of subspecies aizawai, Xentari AS®, had significantly (P < 0.05) higher median lethal concentrations (LC50s) in both insect species than formulations based on subspecies kurstaki. Helicoverpa zea was significantly (P < 0.05) more susceptible than H. virescens to one formulation of subspecies kurstaki (Dipel ES®), but the two insects did not differ in susceptibility to Xentari AS® or to a second formulation of subspecies kurstaki (Dipel 6AF®). In H. virescens, Xentari AS® was additive with Dipel 6AF® and significantly (P< 0.05) antagonistic with Dipel ES® and with a third formulation of subspecies kurstaki, Dipel 48A®. In H. zea, Xentari AS® was significantly antagonistic with all three formulations of subspecies kurstaki. This suggests that certain toxin combinations from B. thuringiensis subspecies might not be effective for managing H. virescens and H. zea populations.

Characterization ofBacillus thuringiensismutants and natural isolates by molecular methods

1997 ◽  
Vol 43 (5) ◽  
pp. 403-410 ◽  
Author(s):  
Yong Chul Jung ◽  
Sung Uk Kim ◽  
Song Hae Bok ◽  
Ho Yong Park ◽  
Jean-Charles Côté ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Bacillus Thuringiensis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Rice Grain ◽  
Chain Reaction ◽  
Hyphantria Cunea ◽  
Natural Isolates ◽  
Grain Dust ◽  
Polymerase Chain

Two Bacillus thuringiensis var. kurstaki HD-1 mutants, two Bacillus thuringiensis var. israelensis HD-500 mutants, and four rice grain dust isolates were characterized using microscopic examination and protein profiles of purified crystals on sodium dodecyl sulfate – polyacrylamide gel electrophoresis. Specific detection of cryI- and cryIV-type genes was performed in a polymerase chain reaction using cryI and cryIV-specific oligonucleotide primers. The cry-type genes under study consisted of cryIA(a), cryI(A)b, cryI(A)c, cryIB, and cryIV. Presence or absence of the cryI- and cryIV-type genes was further confirmed by Southern blotting followed by hybridization with specific cryI and cryIV gene fragments. A genetically modified strain of B. thuringiensis var. kurstaki HD-1, called OZK-13 and obtained following mutagenesis with ozone, was shown to contain cryIA(a), cryIA(b), and cryIA(c) genes. Another kurstaki HD-1 mutant, called NGK-13 and obtained following treatment with N-methyl-N′-nitro-N-nitrosoguanidine (MNNG), was shown to have lost the cryIA(b) gene while retaining the cryIA(a) and cryIA(c) genes. NGI-23-1, an oligosporogenous–multicrystalliferous mutant of B. thuringiensis var. israelensis (Bti) HD-500, obtained following treatment with MNNG contained cryIV-type genes. NGI-22, an oligosporogenous–acrystalliferous mutant of Bti HD-500, contained no cryI- nor cryIV-type genes. The rice grain dust isolate BT-285 contained the cryIA(a) and cryIA(c) genes. Isolate BT-14 contained only the cryIA(c) gene, whereas isolate BT-209 contained cryIA(a), cryIA(b), and cryIB genes. Isolate BT-205 contained no cryI- nor cryIV-type genes. Bacillus thuringiensis mutants and natural isolates shown to contain cryI-type genes were tested for their insecticidal activities in a series of bioassays against Hyphantria cunea Drury (Lepidoptera: Arctiidae). All cryI-carrying strains were toxic against the insect larvae. BT-205 was also tested and exhibited no toxicity against the insect larvae.Key words: Bacillus thuringiensis, δ-endotoxin crystal, cry-type genes, polymerase chain reaction.

scholarly journals The impact of strain diversity and mixed infections on the evolution of resistance to Bacillus thuringiensis

2013 ◽  
Vol 280 (1769) ◽  
pp. 20131497 ◽  
Author(s):  
Ben Raymond ◽  
Denis J. Wright ◽  
Neil Crickmore ◽  
Michael B. Bonsall
Keyword(s):  
Bacillus Thuringiensis ◽  
Transmission Rate ◽  
Diamondback Moth ◽  
Mixed Infections ◽  
Ecological Interactions ◽  
Significant Difference ◽  
Natural Isolates ◽  
Evolution Of Resistance ◽  
Insect Populations ◽  
The Impact

Pesticide mixtures can reduce the rate at which insects evolve pesticide resistance. However, with live biopesticides such as the naturally abundant pathogen Bacillus thuringiensis ( Bt ), a range of additional biological considerations might affect the evolution of resistance. These can include ecological interactions in mixed infections, the different rates of transmission post-application and the impact of the native biodiversity on the frequency of mixed infections. Using multi-generation selection experiments, we tested how applications of single and mixed strains of Bt from diverse sources (natural isolates and biopesticides) affected the evolution of resistance in the diamondback moth, Plutella xylostella, to a focal strain. There was no significant difference in the rate of evolution of resistance between single and mixed-strain applications although the latter did result in lower insect populations. The relative survivorship of Bt- resistant genotypes was higher in the mixed-strain treatment, in part owing to elevated mortality of susceptible larvae in mixtures. Resistance evolved more quickly with treatments that contained natural isolates, and biological differences in transmission rate may have contributed to this. Our data indicate that the use of mixtures can have unexpected consequences on the fitness of resistant and susceptible insects.

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