SUBMITTED TO: SUBMITTED BY:
MISS MANISHA VIKESH KUMAR B.TECH MBA(BIOTECH} ROLL NO. =63
INTRODUCTION
Bacillus thuringiensis is a Gram-positive, soil-dwelling bacterium of the genus Bacillus. Additionally, B. thuringiensis also occurs naturally in the gut of caterpillars of various types of moths and butterflies, as well as on the dark surface of plants.
B. thuringiensis was discovered 1901 in Japan by Ishiwata and 1911 in Germany by Ernst Berliner, who discovered a disease called Schlaffsucht in flour moth caterpillars. B. thuringiensis is closely related to B. cereus, a soil bacterium, and B. anthracis, the cause of anthrax: the three organisms differ mainly in their plasmids.
Zakharyan R.A et al. first reported the presence of plasmids in B. thuringiensis and suggested involvement of the plasmids in endospore/crystal formation. They also described the presence of large plasmid in the Cry+ variant of B. thuringiensis
Upon sporulation, B. thuringiensis forms crystals of proteinaceous insecticidal δ-endotoxins (Cry toxins) which are encoded by cry genes,. It was determined that the "cry" genes are harbored in the plasmids in most strains of B. thuringiensis Cry toxins have specific activities against species of the orders Lepidoptera (moths and butterflies), Diptera (flies and mosquitoes) and Coleoptera (beetles). Upon sporulation, B. thuringiensis forms crystals of proteinaceous insecticidal δ-endotoxins (Cry toxins) which are encoded by cry genes,. It was determined that the "cry" genes are harbored in the plasmids in most strains of B. Thuringiensis .Cry toxins have specific activities