Related Experiment Video
Updated: Apr 20, 2026

The Insect Galleria mellonella as a Powerful Infection Model to Investigate Bacterial Pathogenesis
Published on: December 11, 2012
Toxicity, activation process, and histopathological effect of Bacillus thuringiensis vegetative insecticidal protein
Sameh Sellami1, Maroua Cherif, Lobna Abdelkefi-Mesrati
1Biopesticides Team (LPAP), Center of Biotechnology of Sfax, University of Sfax, P.O. Box 1177, 3018, Sfax, Tunisia.
Abstract:
Tuta absoluta is a destructive moth of Solanaceae plants and especially tomatoes. Here, we considered the entomopathogenic activity of the Bacillus thuringiensis Vip3Aa16 protein heterologously produced by Escherichia coli against T. absoluta. Purified Vip3Aa16 showed lower lethal concentration 50 % against third instar larvae (Toxin/tomato leaf) (335 ± 17 ng/cm(2)) compared to that of B. thuringiensis kurstaki HD1 δ-endotoxins (955 ± 4 ng/cm(2)) (P < 0.05). Action mode examination showed that Vip3Aa16 (88 kDa) was more sensitive to proteolysis activation by the chymotrypsin than the trypsin or the larvae gut soluble proteases, yielding derivative proteins essentially of about 62 and 33 kDa. The gut-soluble proteases could contain trypsin-like enzymes implicated in Vip3Aa16 activation since the proteolysis was inhibited using specific protease inhibitors. Additionally, we showed that the histopathological effect of Vip3Aa16 on T. absoluta larva midguts consisted on a microvillus damage and an epithelial cell rupture.
Related Concept Videos
Production of Biopesticides
Bioactivation and Tissue Toxicity
Toxic Reactions: Overview
Toxicity falls into two primary categories: local and systemic.
Local toxicity appears at the exposure site, such as protein denaturation caused by caustic substances.
In contrast, systemic toxicity requires the toxic agent's absorption and distribution,...
Bacterial Toxins

