Question

Read the passage given below carefully and answer the questions that follow:

The bacterium Bacillus thuringiensis serovar israelensis (Bti) is commercially prepared in various formulations such as liquid, water dispersible granules, powders, and pellets. It is used as a larvicide all over the world due to its ability to produce a toxic protein that primarily targets the larvae of mosquitoes. In Sweden, Bti has been applied on a large scale in the form of commercially available granular formulation Vecto Bac G (Valent BioScience, USA). The applications have taken place in the lower Dalalven River Area to control mass outbreaks of the floodplain mosquito Aedes sticticus.

1. Why does the toxic protein kill the insects but not the bacterium?
2. Can the formulation Vecto Bac G be used to eliminate the species of mosquito referred to above? Why?

Answer 1

1. Protein remains insoluble at low pH in the bacterial cell, but in stomach of insects it becomes soluble and damages the epithelial cells.
2. No, because the toxin is species-specific.