What triggers activation of protoxin to active Bt toxin of Bacillus thorniness in boll worm?

Options

A. Body temperature
B. Moist surface of midgut
C. Alkaline pH of gut
D. Acidic pH of stomach

Answer

To answer the question about what triggers the activation of protoxin to active Bt toxin of Bacillus thuringiensis in the boll worm, we can break down the process into several steps:

### Step-by-Step Solution:

1. **Understanding Bt Toxin and Protoxin**:
- Bacillus thuringiensis (Bt) produces a protein known as protoxin, which is an inactive form of the toxin. This protoxin is not harmful until it is activated.

2. **Ingestion by the Insect**:
- The activation process begins when the boll worm ingests the Bt spores containing the protoxin.

3. **Location of Activation**:
- Once ingested, the protoxin reaches the midgut of the boll worm. The midgut is lined with epithelial cells that play a crucial role in the activation process.

4. **pH Conditions in the Midgut**:
- The midgut of the boll worm has an alkaline pH, typically around 10. This alkaline environment is essential for the activation of the protoxin.

5. **Activation Process**:
- In the alkaline pH of the midgut, the protoxin undergoes a conformational change, which activates it and converts it into the active form of the Bt toxin.

6. **Effect of Active Toxin**:
- The active Bt toxin then binds to the epithelial cells of the midgut, causing cell lysis and ultimately leading to the death of the boll worm.

### Final Answer:
The activation of protoxin to active Bt toxin in the boll worm is triggered by the alkaline pH of the gut (midgut), which is around pH 10.

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