Observing Spores and Crystals of <i>Bacillus thuringiensis</i> under Optical Microscope

In this paper, we reported the experimental protocol of observation Bt spores and crystals under optical microscope. Based on the tool of optical microscope, we can effectively observe spores and crystals, which are the key elements to rapidly identify and distinguish Bt from other members of subgroup of Bacillus cereus in Bacillus genus, such as Bacillus cereus and B. anthracis .