Current Microbiology (2017) 74, 584-588

Hanen Boukedi, Saoussen Ben Khedher, Dhouha Ghribi, Mariam Dammak, Slim Tounsi and Lobna Abdelkefi-Mesrati (2017)
Quantification of Bacillus thuringiensis Vip3Aa16 entomopathogenic toxin using its hemolytic activity
Current Microbiology 74 (5), 584-588
Abstract: Vegetative insecticidal proteins produced by some Bacillus thuringiensis strains are specifically toxic to different agricultural pests such as the polyphagous Spodoptera and several other Lepidopteran insects, but one of the major problems found in the use of these biopesticides was the lack of an easy and credible method of quantification of such secreted toxins. Heterologous expression of B. thuringiensis Vip3Aa16 toxin was performed in Escherichia coli then the protein was purified by chromatography. Using blood agar as well as blood agar overlay (zymogram assay), we reported, for the first time, the capacity of Vip3Aa16 to induce hemolysis. The hemolytic activity of this protein was shown to be relatively stable after treatment at 40 °C and at a range of pH between 6.5 and 9. Moreover, a linear relationship was shown between hemolysis levels and Vip3Aa16 concentrations. The model established in the present study could quantify Vip3A toxin as a function of hemolytic activity and the assay proposed showed to be a simple and low-cost method to readily assess Vip3A toxins in liquid cultures and facilitate the use of this kind of bioinsecticides in pest management programs.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Slim Tounsi

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
molecular biology - genes

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
Bacillus thuringiensis Vip-toxins (entomopathogen)