Article Abstract:
Spores of Bacillus thuringiensis subsp. israelensis and their toxic crystals germinated, grew and sporulated in excreted food vacuoles of Tetrahymena pyriformis forming new active insecticidal crystal proteins in the process. The spores and crystals are concentrated in the food vacuoles of each T. pyriformis cell and delivered to mosquito larvae which soon die. The cells later excrete vacuoles with undigested material. Excreted food vacuoles gradually aggregated and vegetative growth of B. thuringiensis subsp. israelensis was noted with the outgrowth of filaments, which sporulated between 27 and 42 h.
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Article Abstract:
A 21-kilobase (kb) region of the Bacillus thuringiensis 125-kb plasmid possesses four genes encoding delta-endotoxins active against mosquito larvae and two genes encoding regulator polypeptides. The restriction map of the plasmid shows that these genes are placed on a single BamHI fragment without cytA. This convergence enables subcloning of most delta-endotoxin genes as an intact natural fragment. The plasmid map is useful for discovering new delta-endotoxin genes.
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Article Abstract:
A research was conducted investigate the mosquito larvicidal activity of the transgenic cynobacterium Anabaena strain PCC 7120 which expressed genetic combinations of Bacillus thuringiensis subsp. israelensis. Plasmid pSBJ2 was isolated from several colonies of Escherichia coli XL-Blue MRF cells transformed with total DNA prepared. Results indicated a high level of toxicity observed with recombinant clones of Anabaena sp. strain PCC 7120.
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