<Tr> <Td_colspan="2"> Bacillus thuringiensis Berliner 1915 </Td> </Tr> <P> Bacillus thuringiensis (or Bt) is a Gram - positive, soil - dwelling bacterium, commonly used as a biological pesticide . B. thuringiensis also occurs naturally in the gut of caterpillars of various types of moths and butterflies, as well on leaf surfaces, aquatic environments, animal feces, insect - rich environments, and flour mills and grain - storage facilities . It has also been observed to parasitize other moths such as Cadra calidella--in laboratory experiments working with C. calidella, many of the moths were diseased due to this parasite . </P> <P> During sporulation, many Bt strains produce crystal proteins (proteinaceous inclusions), called δ - endotoxins, that have insecticidal action . This has led to their use as insecticides, and more recently to genetically modified crops using Bt genes, such as Bt corn . Many crystal - producing Bt strains, though, do not have insecticidal properties . </P> <P> B. thuringiensis was first discovered in 1901 by Japanese biologist Ishiwatori Shigetane (石渡 繁 胤) in silkworms . He named it Bacillus sotto, using the Japanese word sottō (卒倒,' collapse'), here referring to bacillary paralysis . In 1911, German microbiologist Ernst Berliner independently rediscovered it when he isolated it as the cause of a disease called Schlaffsucht in flour moth caterpillars in Thuringia (hence the specific name thuringiensis, "Thuringian"). B. sotto would later be reassigned as B. thuringiensis var . sotto . </P>

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