• Journal of Microbiology and Biotechnology
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• v.17 no.9
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• pp.1498-1503
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• 2007

To identify novel crystal proteins, Bacillus thuringiensis 2385-1 was isolated from Korean soil samples and characterized. The H-serotype of 2385-1 was identical to that of subsp. kenyae (H4a4c), and its crystal toxin was bipyramidal-shaped. However, 2385-1 showed a much higher toxicity towards Plutella xylostella and Spodoptera exigua larvae than subsp. kenyae. In addition, the crystal protein profile and plasmid DNA pattern of 2385-1 differed from those of subsp. kenyae. To verify the crystal protein gene types of 2385-1, a PCR-RFLP analysis was performed, and the results revealed that 2385-1 contained two novel cry1-type crystal protein genes, cryl-5 and cry1-12, in addition to the crylJal gene. The deduced amino acid sequences of cryl-5 and cry1-12 showed a 97.9% and 75.7% sequence similarity with the CrylAb and CrylJa crystal proteins, respectively. Among the novel crystal proteins, Cry1-5 showed a high toxicity towards P. xylostella and S. exigua larvae. In conclusion, B. thuringiensis 2385-1 is a new isolate in terms of its gene types, and should be a promising source for an insecticide to control lepidopteran larvae.

• International Journal of Industrial Entomology and Biomaterials
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• v.14 no.1
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• pp.33-36
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• 2007

To improve insecticidal activity of B. thuringiensis 2385-1 (Bt 2385-1), a recombinant plasmid, pHT1K-1Ac, was introduced into lepidopteran toxic Bt 2385-1 by electroporation. The presence of the recombinant plasmid in Bt 2385-1 after electroporation was confirmed by PCR. Bt 2385-1 transformant was named as Bt pHT1K-1Ac/2385-1 (1K-1Ac/2385-1). The 1K-1Ac/2385-1 transformant produced bipyramidal-shaped parasporal inclusion as like the wild-type strain, Bt 2385-1, and showed an 130 kDa band of Cry1Ac protein. The insecticidal activity of 1K-lAc/2385-1 against S. exigua was similar to that of Bt 2385-1 but the $LC_{50}$ value of transformant against P. xylostella was 1.8 times lower. Through these bioassay results, it was confirmed that toxicity of Bt 2385-1 transformant showed synergistic effect by introducing Cry1Ac. These results suggested that the multiple expressions of Cry proteins in a promising Bt strain may interact synergistically in insect midgut, resulting in increase of toxicity and expansion of host spectrum.

• Proceedings of the Korean Society of Sericultural Science Conference
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• 2003.04a
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• pp.73-73
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• 2003

Bacillus thuringiensis 2385-1, which showed toxicity to lepidopteran but not to dipteran was isolated from Korean soil sample and characterized. The H-serotype of 2385-1 was identical to that of serovar kenyae (H4a4c), and its crystal toxin was bipyramidal-shaped with a molecular weight of 130 kDa. However, the plasmid profile of 2385-1 was different from that of serovar kenyae. (omitted)

• Proceedings of the Korean Society of Sericultural Science Conference
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• 2003.10a
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• pp.114-115
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• 2003

A Bacillus thuringiensis isolate, Bt 2385-1, which showed toxicity to lepidopteran, was isolated from Korean soil sample and characterized. PCR-RFLP showed that this isolate contains two novel cryl-type crystal protein genes. In this study, we designed cryl-type specific primer set (ATG1-F and N400-R) to clone the toxic domain of the all cryl-type genes. The two novel rlyl-type toxin genes in addition to crylJal gene were cloned and sequenced. (omitted)

• Proceedings of the Korean Society of Applied Entomolohy Conference
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• 2003.10a
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• pp.115-115
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• 2003