• 한국미생물·생명공학회지
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• 제23권4호
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• pp.390-396
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• 1995

Bacillus sphaericus 1593 is a larvicidal toxin-producing mosquitocidal bacterium. The toxin contains a parasporal crystalline inclusion which is composed of a protein that is activated under alkaline condition. To enhance alkaline environment around toxin protein, cryptic plasmid cured, B. sphaericus 1593 was transformed by the Bacillus pasteurii urease gene which generate ammonia from urea. Transformant produced urease at about 80% more than wild type strain. B. sphaericus 1593, and the urease gene was stably maintained. It also produced crystalline toxin protein at the same level as the wild type strain B. sphaericus 1593.

• 한국미생물·생명공학회지
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• 제16권5호
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• pp.389-392
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• 1988

Escheriachia coli pSL 2-1 clone은 Bacillus sphaericus 1593의 모기살충 유전자를 클로닝한 재조합 DNA이다. 이 클론이 생산하는 살충독소 단백질의 분자량을 SDS-polyacrylamide gel을 이용하여 측정했다. B. sphaericus 1593균이 생산하는 독소결정체를 분리하여 전기영동을 한 결과는 6개의 단백질밴드(43, 58, 64, 100, 113, 130Kd)가 형성되었으나, 독소결정체를 알칼리 pH로 용해하여 전기영동을 하면 2개의 단백질 밴드(43과 64Kd)만이 나타났다. 그러나 대장균 pSL2-1균이 생산하는 독소단백질을 Sephadex G-200으로 정제하여 모기유충에 살충력이 있는 단백질을 전기영동한 결과는 42Kd만이 나타났다. LC50은 2 $\mu\textrm{g}$/$m\ell$이었다. B. sphaericus와 pSL2-1 clone 생산하는 살충단백질은 42Kd 단백질인 것으로 생각된다.

• International Journal of Industrial Entomology and Biomaterials
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• 제2권2호
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• pp.185-189
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• 2001

Wild type Bacilus thuringiensis subsp. israelensis and B. sphaericus toxins have been used separately as active in ingredients for bacterial insecticides to control mosquito larvae due to their comparable toxicity to chemical insecticides. Cry11B, recently cloned from B. thuringiensis subsp. jegathesan, shows higher toxicity against three major species of mosquito larvae than Cry11A, one of the major component of B. thuringiensis subsp. israelensis inclusion body. To determine whether the combination of cry11B and B. sphaericus binary toxins is as toxic as B. thuringiensis subsp. israelensis parental strain, cry11B and B. sphaericus binary toxins genes were co-expressed as an operon using cytlA promoters/STAB-SD hybrid expression system in B. thuringiensis subsp. israelensis acrystalliferous strain 4Q7. However, unexpectedly, B. sphaericus binary toxins were barely produced, whereas relatively large amount of Cry11B was produced. When this strain was grown in four different media, NB+G and Peptonized Milk produced more toxin proteins and spores per unit of media than GYS and G-Tris. Toxicity of this strain against fourth instar Culex quinquefasciatus was ranged from of 8.3 to 45.7 ng/ml, with NB+G culture being the highest, and GYS culture was the lowest.

• 한국미생물·생명공학회지
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• 제19권3호
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• pp.308-312
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• 1991

B.thuringiensis subsp. darmstadiensis 73E10-2의 내독소에 대한 화학적 처리에서 고농도의 중성염(4M NaBr), 유기용매(50% acetone), 변성제(4M urea) 및 중성 계면활성제(10% triton X-100)로 내독소를 처리하였을 때 모기유충에 대한 독력의 소실이 거의 나타나지 않았으나, guanidine HCL이나 $CCl_4$ 또는 양이온 및 음이온 계면활성제로 처리함으로써 그 독력이 크게 소실되었다. 또한, 내독소의 sulfhydryl기의 변형은 모기유충에 대한 독력에 영향을 나타내지 못하였으나, lysine기 변형으로 내독소의 독력이 거의 완전히 소실되었다.

• 환경위생공학
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• 제13권2호
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• pp.34-39
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• 1998

For more convenient and rapidly isolation of Bacillus thuringiensis subsp. israelensis(Bti), 1) heat treatment spore forming bacteria, 2) growth in enrichment culture media for Bacillus sp. and 3) selection of bacteria producing a lecithinase for Bacillus thuringiensis subsp. israelensis, were performed. Spore forming bacteria were counted 4.8 $\times $ 10$^{8}$cells/g soil on NAPGCY media, 9.2 $\times $ 10$^{7}$cells/g soil on NA media, and 3.6 $\times $ 10$^{8}$cells/g soil on NAAC media, respectively. Bacteria producing only a lecithinase were reached at 25.2% on medium contained egg york, bacteria only producing a delta-endotoxin were reached at 23.2% by phase contrast microscope, and bacteria producing a lecithinase & a delta-endotoxin simultaneously were reached at 13.7%. Bacillus thuringiensis which producing a lecithinase and a delta-endotoxin simultaneously among bacteria producing a lecithinase, were reached at 56.5%; A half of Bacillus thuringiensis was produced a delta-endotoxin, but not produced a lecithinase. Among 8 isolates of Bacillus thuringiensis, two strain of Bti which has a mosquito-cidal toxin, were detected by PCR using a specific primer of $\delta $-endotoxin gene from Bti.