• 생명과학회지
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• 제6권4호
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• pp.293-298
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• 1996

Thirteen subspecies of Bacillus thuringiensis including B. t. israelensis, B. t. morrisoni PG-14 and B.t. darmstadoemsos known to be toxic to dipteran insects were treated on the mushroom (Flammulina velutipes) compost to estimate the biological control effect of a sciarid fly, Lycoriella sp. According to the results, it was found that there were no significant effects of the tested strains of B, thuringiensis on the control of Lycoriella sp. For further confirmation, larval gut juice of Lycoriella sp. and trypsin were respectively treated into the parasporal crystal proteins of three subspecies of B. t. israelensis, B. t. morrisoni PG-14, and B. t. darmstadiensis. The proteins were separated by SDS-PAGE. According to the results, the major parasporal crystal proteins were respectively produced by B. t. morrisoni as the amount of 52 kd, B. y. israelensis as 37kd and B. t. darmstadiensis as 39kd, but the activity of these proteins could not be unfortunately confirmed in this study.

• 한국잠사학회:학술대회논문집
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• 한국잠사학회 2003년도 제46회 춘계 학술연구 발표회
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• pp.31-32
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• 2003

Bacillus thuringiensis produces insecticidal parasporal inclusions (crystal protein) used as a major ingredient of most microbial insecticides. Although many B. thuringiensis strains and their crystal proteins have been isolated and characterized, such findings have limitation of usefulness. For enhanced toxicity, fast effects, and the delay of resistance development, research on genetic manipulation of crystal genes and proteins by genetic engineering should be continued. (omitted)

• BMB Reports
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• 제44권5호
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• pp.323-328
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• 2011

We screened four B. thuringiensis strains whose parasporal inclusions contained the S-layer protein (SLP), and cloned two slp genes from each strain. Phylogenetic analysis indicated these SLPs could be divided into two groups, SLP1s and SLP2s. To confirm whether SLPs were present in the S-layer or as a parasporal inclusion, strains CTC and BMB1152 were chosen for further study. Western blots with isolated S-layer proteins from strains CTC and BMB1152 in the vegetative phase showed that SLP1s and SLP2s were constituents of the S-layer. Immunofluorescence utilizing spore-inclusion mixtures of strains CTC and BMB1152 in the sporulation phase showed that SLP1s and SLP2s were also constituents of parasporal inclusions. When heterogeneously expressed in the crystal negative strain BMB171, four SLPs from strains CTC and BMB1152 could also form parasporal inclusions. This temporal and spatial expression is not an occasional phenomenon but ubiquitous in B. thuringiensis strains.

• 한국미생물·생명공학회지
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• 제24권2호
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• pp.173-177
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• 1996

Bacillus thuringiensis subsp. morrisoni PG-14 is a gram-positive soil bacterium producing mosquitocidal parasporal inclusions composed of several crystal proteins. Among these crystal protein genes, cryIVD gene is one of major component which has 72 kDa in size. However, these parasporal inclusions sink quickly from the surface of water where mosquito larval feeding occurred. To develope mosquitocidal cyanobacterium, therefore, we constructed the expression vector, pCYASK 5-1 harboring cryIVD gene. The expression vector, pCYASK5-1 was transformed into the cyanobacterium Syne- chocystis PCC6803 reported as a natural mosquito larval food source and the transformants were selected with kanamycin. Expression of IVD gene in transformant was characterized by SDS-polyacrylamide gel electrophoresis (PAGE) and immunoblot analysis. The mosquitocidal activity of a transformant was determined with Culex tritaeniorhynchus. The results showed that, the transformed cyanobacterium is toxic to mosquito larvae and will be expected as a potential agent that is used for mosquito control.

• 한국잠사곤충학회지
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• 제34권1호
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• pp.41-48
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• 1992

해충의 미생물적 방제를 위하여 Bacillus thuringiensis 살충제(BT제) 개발에 관한 기초자료를 얻고자 3균주의 공시균주인 B. thuringiensis var. kurstaki, B. thuringiensis var. dendrolimus, B. thuringiensis var. aizawai와 3종의 공시충으로 누에, 흰불나방, 배추흰나비의 유충을 이용하고 B. thuringiensis 내독소단백질을 alkalidyddor 또는 공시된 3종의 곤충소화액으로 처리하여 전기영동을 비교하여 아래와 같은 결과를 얻었다. 1. 3균주의 B. thuringiensis에서 생산된 내독소단백질은 alkali 또는 곤충의 소화액 처리에 따라서 변화되는 뚜렷한 차이가 없는 것으로 나타났다. 2. 각 균주의 내독소단백질의 분자량은 B. thuringiensis var. aizawai가 130kDa, B. thuringiensis var. kurstaki가 140kDa, 130kDa, 그리고 B. thuringiensis var. dendrolimus가 140kDa의 부분에 2band로 나타났으며, 이들 내독소단백질은 alkali 용액이나 숙주곤충의 소화액으로 처리시 활성화되어 40-65kDa의 저분자 단백질로 전환되었다. 또한 숙주곤충소화액에 따라 내독소단백질의 활성화 속도에 약간의 차이가 있는 것으로 확인되었다.

• Journal of Microbiology and Biotechnology
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• 제14권5호
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• pp.1057-1062
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• 2004

The entomopathogenic bacterium Bacillus thuringiensis is the most widely used biopesticide. Insecticidal proteins, coded by genes located in plasmids, form typical parasporal, crystalline inclusions during sporulation. We isolated a Bacillus thuringiensis strain having insecticidal activity against larvae of the house fly (M. domestica) from the soils at a pig farm in Korea, and named it Bacillus thuringiensis SM. The culture filtrate from Bacillus thuringiensis SM showed strong lethality (83.3%) against M. domestica larvae. The parasporal crystal is enclosed within the spores' outermost envelope, as determined by transmission electron microscopy, and exhibited a bipyramidal form. The crystal proteins of strain SM consisted of five proteins with molecular weights of approximately ~130, ~80, ~68, ~42, and ~27 kDa on a 10% SDS-PAGE (major band, a size characteristic of Cry protein). Examination of antibiotic resistance revealed that the strain SM showed multiple resistant. The strain SM had at least three different plasmids with sizes of 6.6, 9.3, and 54 kb. Polymerase chain reactions (PCRs) revealed the presence of cry1, cry4A2, and cry11A1 genes in the strain SM. The cry1 gene profile of the strain SM appeared in the three respective products of 487 bp [cry1A(c)], 414 bp [cry1D], and 238 bp [cry1A(b)]. However, the strain SM has not shown the cry4A2 md cry11A1 genes. In in vivo toxicity assays, the strain SM showed high toxicity on fly larvae (M. domestic) [with $LC_{50}$ of 4.2 mg/ml, $LC_{90}$ of 8.2 mg/ml].

• 한국응용곤충학회지
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• 제33권3호
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• pp.178-183
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• 1994

Bacillus thuringiensis kurstaki와 aizawai의 내독소단백질을 알카리용액 또는 트립신, 곤충소화액 드응ㄹ 처리하여 전기영동한 후 단백질팬턴을 비교하였다. 두 균주의 주요 결정단백질은 130kd와 64kd의 단백질이었으며, 소화액이나 효소로 처리한 경우 공통적으로 62kd의 활성독소가 생성되었다. 그러나, aizawai는 kurstaki에 비해 현저히 적은 양의 62kd 단백질을 생성하였다. 흰불나방의 유충이 Bacillus thuringiensis 독소를 섭식하였을 때 지방체를 비롯한 몇 가지 조직에서 45kd의 스트레스 단백질이 유발되었는데 이 단백질은 열충격이나 저온 충격시에도 마찬가지로 생성되었다.

• International Journal of Industrial Entomology and Biomaterials
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• 제3권1호
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• pp.19-23
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• 2001

Two B. thuringiensis strains, which possess mosquitocidal activities, were isolated from Korean soil samples and named K-1205-1 and K-1381-1. Serological studies indicated that K-1205-1 and K-1381-1 belonged to B. thuringiensis subsp. kurstaki (H3a3b3c) and subsp. aizawai (H7), respectively. K-1205-1 produced typical bipyramidal parasporal inclusions, but K-1381-1 produced irregular bipyramidal shape. Total plasmid DNA patterns analysis shewed that K-1205-1 and K- 1381-1 were different from their reference strains, subsp. kurstaki and subsp. aizawai, respectively, in high molecules, whereas their crystal protein patterns showed no difference. The cry gene contents of K-1205-1 and K-1381-1 were identical with those of the reference strains. Mosquitocidal activities of crystal proteins produced by K-1205-1 and K-1381-1 were significantly high by about 40-50 folds at $LC_50$ when compared to those of subsp. kurstaki and subsp. aizawai. Finally, in southern blot analysis using cry1A-type specific probe, K-1205-1 and K-1381-1 had different bands from subsp. kurstaki and subsp. aizawai, respectively. In conclusion, our results suggest that K-1205-1 and K-1381-1 appear to be new moquitocidal B. thuringiensis strains isolated from Korean soil.