Cry protoxin is changed into toxic state in

Options

A. Alkaline medium
B. Acidic medium
C. Neutral medium
D. Contact with saliva

Answer

### Step-by-Step Solution:

1. **Understanding Cryoprotoxin**:
- Cryoprotoxin is the inactive form of a toxin produced by the bacterium *Bacillus thuringiensis* (Bt). It is referred to as a "protoxin" because it is not yet in its active toxic form.

2. **Activation of Cryoprotoxin**:
- For cryoprotoxin to become toxic, it needs to be converted into its active form, known as cryotoxin. This conversion occurs when the cryoprotoxin is dissolved.

3. **Conditions for Conversion**:
- The dissolution and activation of cryoprotoxin happen in a specific environment. The key factor is the pH level of the medium where this process occurs.

4. **Identifying the Correct Medium**:
- The video mentions that cryoprotoxin is activated in an alkaline medium. This means that when cryoprotoxin enters the gut of an insect, which has an alkaline pH, it dissolves and becomes cryotoxin.

5. **Conclusion**:
- Based on the information provided, the correct answer to the question "Cry protoxin is changed into toxic state in" is **option 1: alkaline medium**.