Zoology - Biotechnology and Its Applications Question with Solution | TestHub

Bacillus thuringiensisforms protein crystals during a particular phase of their growth. These crystals contain a toxic insecticidal protein. Actually, the Bt toxin protein exists as inactive protoxin but once an insect ingests the inactive toxin it is converted into an active form of toxin, due to the alkaline pH of the gut which solubilizes the crystals. The activated toxin binds to the surface of midgut epithelial and creates pores that cause cell swelling and lysis and eventually cause the death of the insect. Bt is not harmful to humans, other mammals, birds, fish, or beneficial insects. Specific Bt toxin genes were isolated fromBacillus thuringiensisand incorporated into several crop plants such as cotton.