Question

$Bt$ toxin produced by Bacillus thuringiensis does not kill the producer because the toxin is

• A. in an inactive protoxin form
• B. rapidly secreted outside
• C. inactivated by an antitoxin
• D. in unfolded form

Answer 1

Answer: (A)

$Bt$ toxin is produced by Bacillus thuringiensis (soil bacterium). This toxin does not kill the bacteria because when it is present in the bacteria, it is in an inactive and crystalline form. It becomes active and toxic when it is consumed by insects such as lepidopterans (armyworm), coleopterans (beetles) and dipterans (flies/mosquitoes).