• 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.

• 한국미생물·생명공학회지
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• 제15권6호
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• pp.425-429
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• 1987

B. thuringiensis subsp. israelensis 균주가 생성하는 $\delta$-endotoxin의 alkali 용해에서 생성되는 hemolysin fragment 와 extra-cellular hemolysin 의 상관관계를 조사하기 위한 기초자료로서 extra-cellular hemolysin을 분리 정제하여 그 성질을 조사하였다. 균체 배양액에 유안을 염석 및 투석시킨 후, Sephadex G-200 gel filtration 과 DEAE-cellulose column chromatography를 행하여 균체외 homely-sin을 정제하였다. 정제된 extra-cellular hemolysin 은 SDS-polyacrylamide gel 전기영동에서 47,000 dalton의 분자량을 가진 단일 단백질 band를 얻었다. 또한 정제된 hemolysin은 thiol agents에 의해 그 활성이 증가되었으나, cholesterol 및 protease 처리 또는 금속이온 즉, FeSO$_4$나 CuSO$_4$에 의해 그 활성 이 감소되었다.

• 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.

• 한국응용곤충학회지
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• 제49권2호
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• pp.151-158
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• 2010

토양에서 분리한 구형의 내독소단백질을 가지는 18개의 균주 중, 이집트숲모기와 지하집모기에 90%이상의 살충활성을 보이는 Bacillus thuringiensis subsp. israelensis CAB199 균주를 선발하였다. 이 균주는 습지에 발생한 이나도미집모기에도 높은 살충효과를 나타내었다. 모기유충의 행동패턴은 주로 호흡을 위해 수면에서 주로 활동하고 있어, Bti 균주를 유효성분으로 하는 제제가 수면 위에 장시간 부유 할 수 있는 제형을 선발하고자 하였다. 수화제와 액상수화제의 두 가지 형태의 제형을 만들어 실내에서의 살충효과 및 습지에서의 방제효과를 확인한 결과, 실내에서의 경우에는 액상수화제 제형이 실험한 3종의 모기유충에 대해 속효적이며 높은 살충율을 보여주었고, 습지에서도 이나도미집모기에 대하여 가장 좋은 활성을 나타내었다.

• Journal of Microbiology and Biotechnology
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• 제23권1호
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• pp.88-91
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• 2013

The Cyt1Aa protein of Bacillus thuringiensis subsp. israelensis is known to synergize mosquitocidal proteins of B. thuringiensis and Bacillus sphaericus strains. Cyt1Aa is highly lipophilic, and after binding in vivo to the midgut microvillar membrane serves as a "receptor" for mosquitocidal Cry proteins, which subsequently form cation channels that kill mosquito larvae. Here we report that Cyt1Aa can serve a similar function for lepidopteran-specific Cry proteins of B. thuringiensis in certain mosquito larvae. Engineering Cyt1Aa into the HD-1 isolate of B. thuringiensis subsp. kurstaki enhanced toxicity against $4^{th}$ instars of Aedes aegypti, but not against $4^{th}$ instars of Culex quinquefasciatus.

• Journal of Microbiology and Biotechnology
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• 제6권5호
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• pp.326-330
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• 1996

To illustrate whether a hemolysin in $\delta$-endotoxins of Bacillus thuringiensis strain 73E10-2 and subsp. israelensis had immunological identity, a cyt gene of the strain 73E10-2 which encodes a hemolysin was cloned to B. subtilis (transformant 2753). The transformant 2753 containing cyt gene produced the hemolysin which lysed sheep erythrocytes after treatment of proteinase K. The hemolysin was proved also to be toxic against mosquito larvae (Aedes aegypti). The molecular weight of the hemolysin produced from the transformant 2753 was determined to be about 25 kDa by SDS-PAGE and immunoblot. The hemolysin in $\delta$-endotoxin of subsp. israelensis and subsp. kyushensis did not react on immunoblot using polyclonal anti-$\delta$-endotoxin of the strain 73E10-2, but 70-140 kDa mosquitocidal toxins in $\delta$-endotoxin of subsp. kyushuensis reacted.

• International Journal of Industrial Entomology and Biomaterials
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• 제9권2호
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• pp.183-186
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• 2004

Recently, we have developed an easy, simple and convenient circular DNA cloning system named plasmid capture system (PCS). To investigate usefulness of PCS in cloning of plasmids from Bacillus thuringiensis strains, PCS donors, pPCS-S and pPCS-L were applied to clone plasmids of B. thuringiensis subsp. israelensis by in vitro transposition using 4{TnsABC^*}$ transposase. In result, 3 small plasmids were cloned, and these were consistent with pTX14-1, pTX14-2 and pTX14-3 reported previously from B. thuringiensis subsp. israelensis. Therefore, the PCS can be successfully applied to clone small plasmids from B. thuringiensis strains.

• 한국미생물·생명공학회지
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• 제18권3호
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• pp.301-304
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• 1990

Bti와 Btd의 내독소에 대한 면역학적인 검토를 행한 결과 양균주의 내독소에는 동일한 기원의 단백질이 혼존하고 있음을 면역확산반응 및 면역전기영동법으로 확인되었다. 또한 동일한 기원의 단백질 함량은 Bti 내독소 보다 Btd 내독소에 많이 존재함을 효소항체법으로 확인하였다.

• 한국미생물·생명공학회지
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• 제27권5호
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• pp.359-363
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• 1999

To prevent appearance of resistant mosquitoes against $\delta$-endotoxin of bacillus thuringiensis subsp. israelensis (Bti) in field, a mosquitocidal Bacillus thuringiensis strain 21-2(Bt21-2) producing a new type of $\delta$-endotoxin was isolated. The strain Bt 21-2 belongs to H serotype 43, B. thuringiensis subsp. guiyangiensis (Btg). The $\delta$-endotoxins from the strain Bt 21-2 and the strain Bti were a cuboid shape morphologically, but the $\delta$-endotoxin of the strain Bt 21-2 was composed of 150, 90 and 70kDa proteins on SDS-PAGE, and the antigenicity of $\delta$-endotoxin of the strain Bt 21-2 was different from that of the strain Bti on immunoblot. The $\delta$-endotoxin gene of the strain Bt 21-2 was not amplified with specific primers of $\delta$-endotoxin gene (cry4A and cry4B) of the strain Bti on PCR.

• 한국미생물·생명공학회지
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• 제21권5호
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• pp.393-398
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• 1993

One strain of mosquitocidal Bacillus thuringiensis, H9B, was isolated from soil. The biochemical characteristics and flagella antigenicity of the strain H9B is similar to that of B. thuringiensis subsp. darmstadiensis. The delta-endotoxin of the strain H9B coincided with that of B. thuringiensis subsp. darmstadiensis strain 73E10-2 on agarose double immunodiffusion test. The delta-endotoxin of B. thuringiensis subsp. israelensis contains hemolysin fragment (28 kb) on SDS-PAGE when the delta-endotoxin was solubilized in alkali, while that of the strain H9B does not contain 28 kb protein.