Abstract
The Bacillus thuringiensis (Bt) is a bacterium which mostly has insects as hosts. When the growing conditions are bad (lack in nutrients, bad temperature etc.), Bt produces spores, sleeping forms of the bacterium, which are able to resist even extreme conditions. What makes Bt different from other bacteria, is its capacity to produce crystals during sporulation. These crystals contain toxic proteins mostly directed against insects (used in agriculture). When the insect is dead, the spores use the nutrients released to grow again. Researchers have created many mutants to try to control the rate of toxin production within this bacteria.
