Effect of Bacillus thuringiensis naturally colonising Brassica campestris var. chinensis leaves on neonate larvae of Pieris brassicae

2009 ◽  
Vol 100 (3) ◽  
pp. 193-194 ◽  
Author(s):  
A. Prabhakar ◽  
A.H. Bishop
Keyword(s):  
Bacillus Thuringiensis ◽  
Brassica Campestris ◽  
Pieris Brassicae ◽  
Neonate Larvae

scholarly journals Purification of a protein from Bacillus thuringiensis toxic to larvae of lepidoptera

1968 ◽  
Vol 106 (2) ◽  
pp. 445-454 ◽  
Author(s):  
K. E. Cooksey
Keyword(s):  
Bacillus Thuringiensis ◽  
Gel Filtration ◽  
Pieris Brassicae ◽  
Digestion Product ◽  
Toxic Protein ◽  
Protein Toxin ◽  
Ammonium Sulphate Precipitation ◽  
Alkaline Conditions ◽  
Crystal Toxin

The protein toxin of the parasporal body or crystal of Bacillus thuringiensis (Mattés isolate) has been purified severalfold by a combination of Sephadex G-200 gel filtration and ammonium sulphate precipitation. It has been shown that the use of highly alkaline conditions for dissolution of the crystals does not lead to serious artifacts. The crystal toxin has been shown to be quantitatively related to the crystal antigen. It is possible that there is a second distinct toxin present in the crystal and this too can be detected by its antigenic reaction. Purified toxic protein has been hydrolysed in vitro by regurgitated Pieris brassicae gut enzymes, chymotrypsin, trypsin and subtilisin. In each case the digest contained a product that was still antigenic, had mol.wt. about 40000 and was toxic to P. brassicae larvae. Smaller toxic molecules (mol.wt. approx. 10000) that did not react as antigens were also produced by proteolysis. It is possible that these smaller molecules were hydrolytic products of the larger digestion product.

scholarly journals The construction of Bacillus thuringiensis strains expressing novel entomocidal δ-endotoxin combinations

1990 ◽  
Vol 270 (1) ◽  
pp. 133-136 ◽  
Author(s):  
N Crickmore ◽  
C Nicholls ◽  
D J Earp ◽  
T C Hodgman ◽  
D J Ellar
Keyword(s):  
Bacillus Thuringiensis ◽  
Parent Strain ◽  
Pieris Brassicae ◽  
Toxin Gene ◽  
Delta Endotoxin ◽  
Cabbage White Butterfly

Using our recently reported method of electroporation to transform Bacillus thuringiensis [Bone & Ellar (1989) FEMS Microbiol. Lett. 58, 171-178], cloned B. thuringiensis entomocidal delta-endotoxin genes have been introduced into several native B. thuringiensis strains. In many cases the resulting transformants expressed both their native toxins and the cloned toxin, producing strains with broader toxicity spectra. The introduction of the var. tenebrionis toxin gene into B. thuringiensis var. israelensis resulted in a strain with activity against Pieris brassicae (cabbage white butterfly), an activity which neither parent strain possesses. We discuss further the possibility of synergism and also the problems associated with introducing cloned DNA by this method.

scholarly journals A Strain of Bacillus thuringiensis Containing a Novel cry7Aa2 Gene That Is Highly Toxic to Leptinotarsa decemlineata (Say) (Coleoptera; Chrysomelidae)

2019 ◽  
Author(s):  
Mikel Dominguez- ◽  
Maite Villanueva ◽  
Ana Beatriz Fernandez ◽  
Primitivo Caballero
Keyword(s):  
Amino Acid ◽  
Bacillus Thuringiensis ◽  
Molecular Mass ◽  
Leptinotarsa Decemlineata ◽  
Insect Pests ◽  
Amino Acid Residues ◽  
Cry Protein ◽  
Sds Page ◽  
Neonate Larvae

The genome of the Bacillus thuringiensis BM311.1 strain was sequenced and assembled in 359 contigs containing a total of 6,390,221 bp. The plasmidic ORF of a putative cry gene from this strain was identified as a potential novel Cry protein of 1138 amino acid residues with a 98% identity respect to Cry7Aa1 protein and a predicted molecular mass of 129.4 kDa. The primary structure of this Cry7Aa2 protein, which revealed the presence of eight conserved blocks and the classical structure of three domains, differed in 28 amino acid residues from that of Cry7Aa1. The cry7Aa2 gene was amplified by PCR and then expressed in the acrystalliferous strain BMB171. SDS-PAGE analysis confirmed the predicted molecular mass for the Cry7Aa2 protein and revealed that, after in vitro trypsin incubation, it was degraded to a toxin of 62 kDa. However, when treated with digestive fluids from Leptinotarsa decemlineata larvae two proteinase-resistant fragments of 60 and 65 kDa were produced. Spore and crystal mixture produced by the wild-type BM311.1 strain against L. decemlineata neonate larvae resulted in a LC50 (18.8 μg/ml), which was statistically equal to the estimated LC50 (20.8 μg/mL) for the recombinant BMB17-Cry7Aa2 strain. In addition, when this novel toxin was activated in vitro with commercial trypsin, the LC50 value was reduced 4 times approximately (LC50 = 4.9 μg/mL). The advantages of Cry7Aa2 protoxin compared to Cry7Aa1 protoxin when used in the control of insect pests are discussed.

Dispersal ofBacillus thuringiensisvar.kurstakiin an experimental cabbage field

1995 ◽  
Vol 41 (2) ◽  
pp. 118-125 ◽  
Author(s):  
Jens Christian Pedersen ◽  
Bjarne Munk Hansen ◽  
Per Hyldebrink Damgaard ◽  
Jørgen Eilenberg
Keyword(s):  
Population Dynamics ◽  
Bacillus Thuringiensis ◽  
Half Life ◽  
Pieris Brassicae ◽  
Carabid Beetles ◽  
Colony Forming Units ◽  
Sterile Medium ◽  
Surface Active ◽  
Rain Splash

The field population dynamics of Bacillus thuringiensis var. kurstaki DMU67R isolated from cabbage leaves was investigated. Two experimental cabbage plots were spray inoculated with a suspension of sporulated bacteria containing 6.5 × 107colony-forming units (cfu)/mL DMU67R or with a sterile medium control. To study transport between phyllosphere and soil, plastic covering was used during spraying to ensure that DMU67R was applied only on leaves (8.5 × 106cfu/g) or on soil (1.2 × 104cfu/g). Numbers of DMU67R declined five log units during the first 4 weeks after spraying of leaves; the initial half-life (1st week) was 16 h. In topsoil, however, a long-term persistency was demonstrated with a half-life exceeding 100 days. Dispersal by rain splash from topsoil to lower leaves of cabbage was demonstrated. After 1 year, analysis of the top 15 cm of soil showed that 77% of DMU67R remained in the 0- to 2-cm topsoil layer. When DMU67R was applied on leaves, larvae of Pieris brassicae were killed within 7 days after spraying. Germination of DMU67R was demonstrated in dead P. brassicae larvae but not in any leaf or soil sample. Pitfall sampling demonstrated dispersal of DMU67R by means of carabid beetles (up to 135 m) and other surface-active insects carrying 102–103 cfu/g wet mass.Key words: Bacillus thuringiensis, Pieris brassicae, cabbage, soil, dispersal, population dynamics.

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