• Journal of Microbiology and Biotechnology
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• v.14 no.4
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• pp.772-776
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• 2004

Physiological and molecular characteristics of Bacillus thuringiensis SR6 and SR8 were investigated, and phase contrast and electron microscopies revealed that a large rhomboidal crystal protein was present in the sporulating cells. SDS-PAGE and Western blot analyses showed that B. thuringiensis SR8 produced 70 kDa protein much more than other proteins, and that the 70 kDa protein could bind to the antibody of B. thuringiensis subsp. tenebrionis-crystal toxin protein, indicating that the crystal 70 kDa protein has an immunological homology with B. thuringiensis subsp. tenebrionis-crystal toxin protein. The DNA fragment of B. thuringiensis subsp. tenebrionis-toxin gene was detected in B. thuringiensis SR6 and SR8 by using PCR amplification analysis. Furthermore, the insect bioassay showed the insecticidal activity against Colorado potato beetle larvae. Based on the physiological and molecular similarities to B. thuringiensis subsp. tenebrionis, it is suggested that the B. thuringiensis SR6 and SR8 may be mutants of the B. thuringiensis subsp. tenebrionis strain overexpressing the crystal of 70 kDa toxin protein.

• International Journal of Industrial Entomology and Biomaterials
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• v.2 no.2
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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.

• Journal of Sericultural and Entomological Science
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• v.38 no.2
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• pp.154-159
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• 1996

To isolate Bacillus thuringiensis toxic to Spodoptera species, we collected soil samples in Korea. In these samples, we characterized 7 B. thuringiensis isolates toxic to spodoptera exigua or S. litura from soil, granary and sericultural farm samples. The 7 isolates were named B. thuringiensis STB-1, STB-2, STB-3, STB-4, STB-5, STB-6 and STB-7, respectively. The bioassay of these isolates against S. exigua and S. litura showed highly insecticidal activity. The serotypes of them were determined by agglutination tests using 33 antisera ; STB-1 an STB-2 are identical to B. thuringiensis subsp. kurastaki, and STB-3, STB-4 and STB-5 are identical to subsp. kenyae. STB-6 and STB-7 did not react with 33 antisera. STB-1 and STB-3 which have different gene types from B. thuringiensis subsp. kurastaki and subsp. kenyae are identified new isolates. STB-6 and STB-7 which show no agglutination in serological tests havd cryIA(a), cryIA(b), cryIC, and cryII genes are also identified new isolates. Molecular weights of parasporal inclusions of all isolates were determined approximately 130 kDa by SDS-polyacrylamide gel elctrophoresis.

• Journal of Microbiology and Biotechnology
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• v.4 no.3
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• pp.171-175
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• 1994

To find new crystal protein genes, we screened 42 Bacillus thuringiensis strains of serovar standards by Southern hybridization with a cryI-specific probe which was amplified from B. thuringiensis subsp. kurstaki HDl by polymerase chain reaction (PCR). Two strains, B. thuringiensis subsp. entomocidus HD9 and subsp. subtoxicus HD109, generated weak signals under the low-stringency hybridization conditions. Further analysis with Southern hybridization revealed that the two strains contained cryIB genes which are slightly different from those of B. thuringiensis subsp. thuringiensis HD2. These results were confirmed by PCR with cryIB-specific primers followed by the restriction analysis of PCR products.

• Microbiology and Biotechnology Letters
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• v.18 no.3
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• pp.301-304
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• 1990

In the mosquitocidal delta-endotoxins from Bacillus thuringiensis subsp, isruelensis and B. thuringiensis subsp. darmstudiensis 73E10-2, were contained an immunologically homologous protein. The homologous protein was confirmed from Ouchterlony test, irnmuno-electrophoresis, and enzyme linked immunoassay by polyclonal antibodies against the delta-endotoxins of both strains.

• Microbiology and Biotechnology Letters
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• v.21 no.5
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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.

• The Korean Journal of Pesticide Science
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• v.15 no.2
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• pp.166-176
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• 2011

Bacillus thuringiensis CAB530 was isolated from dead Anomata albopilosa (Rutelidae: Coleoptera) and soil of green tea field, and confirmed its insecticidal activities. CAB530 isolate showed a high insecticidal activity against the beet armyworm among the many lepidopteran insects that are difficult to control. $LC_{50}$ value of CAB530 isolate against the second larva of Spodoptera exigua was $1.49{times}10^4$ spore concentration (cfu/$m{\ell}$). SDS-PAGE result of insecticidal toxin protein of CAB530 isolate showed a band at 130 kDa that is similar pattern with B. thuringiensis subsp. kurstaki that took insecticidal activity against S. exigua. Otherwise, the crystal protein of the CAB530 isolate was conformed at 65 kDa level after 30 minute of incubation in S. exigua midgut juice. Six crystal genes (cry1Aa, cry1Ab, cry1C, cry1D, cry1F and cry1I) were identified by PCR. It different from genes of B. thuringiensis subsp. kurstaki. Crystal shape and pattern of toxin protein was similar with B. thuringiensis subsp. kurstaki, however, insecticidal activity and PCR result of CAB530 isolate was similar with B. thuringiensis subsp. aizawai.

• Microbiology and Biotechnology Letters
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• v.19 no.3
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• pp.303-307
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• 1991

The hemolyic polypeptide in delta-endotoxin from Bacillus thun'ngiensis subsp. darmstadiensis 73ElO-2 was purified by Sephadex G-IOO gel filtration and DEAE-cellulose ion exchange column chromatography. The purity of hemolysin was confirmed by ouchterlony test and SDS-PAGE. The molecular weight of the purified hemolysin was approximately 64 KDa by SDS-PAGE. The purified hemolysin has not mosquitocidal activity against larvae of Aedes agypti, but hemolytic activity on red blood cells of rat. There is no serological relationship between delta-endotoxin from B. thuringiensis subsp. israelensis and the purified hemolysin from the . strain 73ElO-2.

• Journal of Microbiology and Biotechnology
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• v.23 no.1
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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.

• Korean journal of applied entomology
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• v.47 no.4
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• pp.457-465
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• 2008

Eight Bacillus thuringiensis strains activated against mosquito larva were compared their characterization. Spherical-shaped parasporal inclusion of B. thuringiensis subsp. tohokuensis CAB167 was observed by phase-contrast microscopy and scanning electron microscopy. $LC_{50}$ values of B. thuringiensis subsp. tohokuensis CAB167 against Culex pipiens molestus, Culex pipiens pallens, and Aedes aegyti were 173, 190 and 580 ng/ml, respectively. B. thuringiensis subsp. tohokuensis CAB167 had a parasporal inclusion containing 4 major protein components, for example, 135, 80, 49 and 28-kDa by SDS-PAGE. Otherwise, after trypsin digestion of parasporal inclusion, SDS-PAGE was showed new protease-resistant peptides at 72 and 63-kDa. Activated toxins of isolated CAB167 were different from other reference strains on a serological by immuno-diffusion test.