Question
Biology Question on Applications of Biotechnology
What is true about Bt toxin?
Bt protein exists as active toxin in the Bacillus.
the activated toxin enters the ovaries of the pest to sterilise it and thus prevent its multiplication.
the concerned Bacillus has antitoxins.
the inactive protoxin gets converted into active form in the insect gut.
the inactive protoxin gets converted into active form in the insect gut.
Solution
The cry gene of Bacillus thuringiensis produces Bt protein which forms crystalline inclusion in the bacterial spores. The crystal proteins are inactive (prototoxins) in the bacterial body but when they enter in the insect gut they convert into active form due to the alkaline pH of the alimentary canal that solubilizes the crystals. The activated toxin binds to the surface of midgut epithelial cells and creates pores which cause cell swelling and lysis and finally cause death of insect.