• The Journal of Natural Sciences
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• v.6 no.1
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• pp.41-48
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• 1993

A cloned delta-endotoxin gene from Bacillus thuringiensis var. kurstaki NRD 6 was mutated at N-terminal toxic portion of the protoxin by site-directed mutagenesis. A Stu 1 restriction site was created in protoxin region of the mutant B.t.kurstaki NRD 6-Stu 1 which changed A to C in 177 region of the protoxin(silent mutation). Antigenic property of crystalline inclusion (delta-endotoxin) of the mutant was no difference to intact strain by the western blot analysis and its toxidity threshold value was also showed 0.015~0.030ng against Choristoneura femiferana-1 insect, similar with 0.01~0.024ng of parent strain, but stronger than that of B.t.kurstaki NRD 5 (500~1000ng) and B.t.kurstaki NRD 4(none toxic).

• Korean Journal of Food Science and Technology
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• v.52 no.6
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• pp.678-684
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• 2020

The objective of this study was to identify the fermentation characteristics of Bacillus thuringiensis and emetic, non-emetic Bacillus cereus using analytical profile index (API) test. Ten strains of B. thuringiensis and 10 strains of B. cereus including 3 strains of emetic type were used at the same concentrations. The differences of fermentation characteristics between the B. thuringiensis and B. cereus was not obvious, but the differences between the non-emetic and emetic B. cereus were distinctive. Seven among 50 substrates were negative for all non-emetic B. cereus strains and positive for all emetic strains, and three substrates among additional 12 substrates had the same tendency. From these differences, 3 emetic B. cereus strains were not indicated as B. cereus by API test. These results indicate that API test is not a suitable method to identify some strains of emetic B. cereus, and the distinctive differences in substrate utilization can be used to improve selective media.

• 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.14 no.4
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• pp.329-334
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• 1986

Bacillus thuringiensis serovar israelensis H 14 strain was cultured in 4 different fermentation M-media and then measured the rates of their growths and the productions of endotoxin crystals front the media. Out of the four M-media the production of endotoxin crystals and spores was maximal in M-4 medium (pH 9). The wet weight of the cells grown in the 150$m{\ell}$ culture was approximately 3.901g and the number of viable spores was 1.53$\times$10$^{12}$ per nil and the ratio of the endotoxin over the total cell weight was 18.54%. The generation time was about 89.3 minutes in the M-1 medium, 124.1 minutes in the M-2, 97 minutes in the M-3, 130.8 minutes in the M-4. The proper pHs for the production of the endotoxin appeared to be 6.5 to 7.5.

• Korean Journal of Organic Agriculture
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• v.19 no.spc
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• pp.259-262
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• 2011

In organic Chinese cabbage fields, Commercial Bacillus thuringiensis products are used widely against diamond back moth, Plutella xylostella. We conducted the study to determine the effective spray-interval of commercialized B. thuringiensis against diamond back moth on Chinese cabbages. Chinese cabbage leaves were collected 0, 1, 2, 3, 6, 10days after treatment in first trial and 0, 2, 4, 7, 9, 11days after treatment. We compared the insecticidal property of sprayed B. thuringiensis and the density of it on surface of Chinese cabbages using collected leaves. The insecticidal property maintained high until nine days after commercial B. thuringiensis products sprayed.

• Journal of Sericultural and Entomological Science
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• v.34 no.1
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• pp.41-48
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• 1992

Dissolution and degradation of the parasporal crystal proteins produced from B. thuringiensis var. kurstaki, B. thuringiensis var. dendrolimus and B. thuringiensis var. aizawai were investigated. SDS-polyacrylamide gel electrophoresis analysis showed that the crystals contained major protein with molecular weight of approximately 134 kDa for B. thuringiensis var. aizawai 143 kDa for B. thuringiensis var. kurstaki and 149 kDa for B. thuringiensis var. dendrolimus, respectively. Crystals of three other strains were incubated alkali solutions at various pH or gut juice of Silkwarm Bombyx mori, Fall webworm Hyphantria cunea, and Common Cabbage worm Pieris rapae. When crystals of these strains were solubilized by alkali solutions, no major differences among strains B. thuringiensis could be detected. Among the strains studied, crystal protins (130-66 kDa) consist of protease resistant polypeptides in the 45-66 kDa size range when treated with gut juice of three insect species.

• Korean journal of applied entomology
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• v.36 no.3
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• pp.264-269
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• 1997

Four strains of Bacillus thuringiensis were isolated froin the dead larvae of mulberry longicorn beetle (Apriong germari) and dung beetle (Aphodius apicalis). One nf four B. thuringiensis isolates turned out to be subspecies darinstadiensis but the remains were not identified using 33 B. thuringiensts flgellar ( H ) antibodies. Furthermore. bioassays of spore-parasporal inclusion protein mixture conducted against third instar larvae of A. gerrntrri or A. apicalis, second instar larvae of Bombyx mori, and third instar larvae of Cu1ex pipiens pullens showed that the isolates were non-toxic. To further confirm, four isolates were characterized and analysed by SDS-PAGE and agarose gel electrophoresis. The results revealed that parasporal protein and plasmid DNA patterns of four isolates are different from those of darmstadiensis and 20 known non-toxic B. thuringiensis strains, suggesting that the four isolates are novel non-toxic B. thuringiensis.

• 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.

• The Korean Journal of Food And Nutrition
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• v.9 no.4
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• pp.459-465
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• 1996

Bacillus thuringiensis serovar. darmstadiensis produced bipyramidal endo-toxin. The toxin protein was purified by Renografin-76 step gradient centrifugation and investigated by electron microscope. Analysis of total plasmid DNA patterns showed that four different size of plasmids existed in wild type B. thuringiensis serovar. darmstadiensis. Total plasmids DNA was isolated and transformed into pst I site of pBR322 cloning vector. Ten clones containing crystal toxin gene were forst screened colony hybridization by using PUYBT 9044 probe ontained B. thuringiensis kurskaki HD 1 toxin gene. Cloned-DNA was digested with EcoR1 and HindIII and transformed to pIBI30 sequencing vector. Finally, 2.6kb and 3.6kb size fragments contatined toxin-gene were cloned with restriction analysis.

• 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.