scholarly journals Poly-β-hydroxybutyrate Metabolism Is Unrelated to the Sporulation and Parasporal Crystal Protein Formation in Bacillus thuringiensis

2016 ◽  
Vol 7 ◽  
Author(s):  
Xun Wang ◽  
Zhou Li ◽  
Xin Li ◽  
Hongliang Qian ◽  
Xia Cai ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Crystal Protein ◽  
Parasporal Crystal ◽  
Parasporal Crystal Protein

scholarly journals Dose Response of Omnivorous Leafroller to Commercial Formulations of Bacillus Thuringiensis Var. Kurstaki in the Laboratory, 1992

1994 ◽  
Vol 19 (1) ◽  
pp. 370-370
Author(s):  
J. Steven Tebbets ◽  
Patrick V. Vail
Keyword(s):  
Dose Response ◽  
Crystal Protein ◽  
Protein Bodies ◽  
Bacterial Cells ◽  
Parasporal Crystal ◽  
First Instar ◽  
Parasporal Crystal Protein ◽  
Live Bacteria ◽  
Omnivorous Leafroller ◽  
Feeding Trials

Abstract We compared three formulations of B. thuringiensis var. kurstaki (Btk) for their insecticidal activity against first-instar OLR. Products tested included: (1) NOVO Laboratories Biobit, a flowable concentrate containing live bacteria with spores and parasporal crystal protein bodies; (2) Abbott Laboratories Dipel 2X, a wettable powder also containing active bacteria with spores and parasporal crystal protein bodies; and (3) Mycogen Corporations MVP Bioinsecticide, a flowable concentrate containing dead bacterial cells which bioencapsulate the Btk proteins. The AI in each of these products is the insecticidal protein, or delta-endotoxin, of Btk. Dose-response was determined by feeding trials exposing first-instar OLR to each product. Serial dilutions of each formulation were made and 10 μ1 of each dilution was applied to the surface of an agar-based diet (Bioserv No. 9370) and then allowed to air dry. One larva was placed in each vial containing ca. 1 ml of surface-contaminated diet (surface area = 1 cm2). Thirty to 60 larvae were observed for each dilution and formulation tested. Doses were expressed in mg AI per sq. cm. Mortality evaluations were made after 3, 5, and 7 days. Response data were analyzed by the POLO-PC PROBIT procedure (LeOra Software, 1987).

scholarly journals Parasporal Body Formation via Overexpression of the Cry10Aa Toxin of Bacillus thuringiensis subsp. israelensis, and Cry10Aa-Cyt1Aa Synergism

2009 ◽  
Vol 75 (14) ◽  
pp. 4661-4667 ◽  
Author(s):  
Alejandro Hernández-Soto ◽  
M. Cristina Del Rincón-Castro ◽  
Ana M. Espinoza ◽  
Jorge E. Ibarra
Keyword(s):  
Bacillus Thuringiensis ◽  
Gradient Centrifugation ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Microbial Control ◽  
Control Agent ◽  
Mass Spectrometry Analysis ◽  
Parasporal Crystal ◽  
Spectrometry Analysis ◽  
Crystal Complex

ABSTRACT Bacillus thuringiensis subsp. israelensis is the most widely used microbial control agent against mosquitoes and blackflies. Its insecticidal success is based on an arsenal of toxins, such as Cry4A, Cry4B, Cry11A, and Cyt1A, harbored in the parasporal crystal of the bacterium. A fifth toxin, Cry10Aa, is synthesized at very low levels; previous attempts to clone and express Cry10Aa were limited, and no parasporal body was formed. By using a new strategy, the whole Cry10A operon was cloned in the pSTAB vector, where both open reading frames ORF1 and ORF2 (and the gap between the two) were located, under the control of the cyt1A operon and the STAB-SD stabilizer sequence characteristic of this vector. Once the acrystalliferous mutant 4Q7 of B. thuringiensis subsp. israelensis was transformed with this construct, parasporal bodies were observed by phase-contrast microscopy and transmission electron microscopy. Discrete, ca. 0.9-μm amorphous parasporal bodies were observed in the mature sporangia, which were readily purified by gradient centrifugation once autolysis had occurred. Pure parasporal bodies showed two major bands of ca. 68 and 56 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis. These bands were further characterized by N-terminal sequencing of tryptic fragments using matrix-assisted laser desorption ionization-time of flight mass spectrometry analysis, which identified both bands as the products of ORF1 and ORF2, respectively. Bioassays against fourth-instar larvae of Aedes aegypti of spore-crystal complex and pure crystals of Cry10Aa gave estimated 50% lethal concentrations of 2,061 ng/ml and 239 ng/ml, respectively. Additionally, synergism was clearly detected between Cry10A and Cyt1A, as the synergistic levels (potentiation rates) were estimated at 13.3 for the mixture of Cyt1A crystals and Cry10Aa spore-crystal complex and 12.6 for the combination of Cyt1A and Cry10Aa pure crystals.

The C-terminal domain of the toxic fragment of a Bacillus thuringiensis crystal protein determines receptor binding

1991 ◽  
Vol 5 (11) ◽  
pp. 2799-2806 ◽  
Author(s):  
G. Honée ◽  
D. Convents ◽  
J. Rie ◽  
S. Jansens ◽  
M. Peferoen ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Receptor Binding ◽  
Crystal Protein ◽  
Terminal Domain
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