Question

What triggers activation of protoxin to active Bt toxin of Bacillus thuringiensis in bollworm?

• A. Body temperature
• B. The moist surface of midgut
• C. Alkaline pH of gut
• D. Acidic pH of the stomach

Answer 1

The correct option is C

Alkaline pH of gut

The correct option is C.

Explanation of the correct option:

1. The Bt toxin is a crystal protein produced by the bacterium Bacillus thuringiensis through the process of sporulation.
2. Initially, these protoxins are inactive after ingestion by the insect, changing the environment, which has to have high pH of the gut or alkaline pH, making them active.
3. This activated toxin binds to the surface of epithelial cells and makes pores causing swelling and lysis leading to the death of bollworm.

Explanation of the incorrect options:

Options A: No effects of body temperature are seen on the activation of protoxins.

Option B: The moist surface of the midgut does not trigger the activation of the protoxins.

Option D: Acidic pH is not able to solubilize protein crystals.

Final Answer: Hence, alkaline pH of gut triggers activation of protoxin to active Bt toxin of Bacillus thuringiensis in bollworm