• The Plant Pathology Journal
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• v.35 no.5
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• pp.486-497
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• 2019

Citrus canker is a devastating disease of citrus caused by Xanthomonas citri subsp. citri (Xcc). A total of 134 endophytic bacteria were isolated from various gymnospermic and angiospermic plants. They were screened for their antagonistic activities against three wild-type and six streptomycin-resistant Xcc strains. TbL-22 and TbL-26, both later identified as Bacillus thuringiensis, inhibited all the wild and resistant Xcc strains. TbL-22 exerted the highest antagonistic activity against XccW3 and XccM6 with inhibition zones of $20.64{\pm}0.69$ and $19.91{\pm}0.87mm$, respectively. Similarly ethyl acetate extract of TbL-22 showed highest inhibition zones $15.31{\pm}2.08$ and $19.37{\pm}3.17mm$ against XccW3 and XccM6, respectively. TbL-22 reduced canker incidence on infected leaves by 64.05% relative to positive controls. Scanning electron microscopy revealed that the cell membranes of Xcc treated with ethyl acetate extract of TbL-22 were ruptured, lysed, and swollen. B. thuringiensis TbL-22 can effectively and sustainably controls streptomycin-resistant citrus canker.

• International Journal of Industrial Entomology and Biomaterials
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• v.1 no.2
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• pp.115-122
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• 2000

A Bacillus thuringiensis designated NT0423, belonging to B. thuringiensis subsp. aizawai (H 7), was isolated from samples of dust and soil of sericultural farms. B. thuringiensis NT0423 having dualspecificity against Lepidoptera and Diptera produced bipyramidal inclusions consisting of two major polypeptides of approximately 130- and 70-kDa. Proteolytic processing by trypsin and gut juice of Bombyx mori yielded predominant proteins with molecular masses of about 66-kDa. The whole crystal protein of B. thuringiensis NT0423 immunologically was related to that of B. thuringiensis subsp. aizawai. PCR analysis showed that B. thuringiensis NT0423 has at least five crystal protein genes including cryIA(a), cryIA(b), cryIC, cryID and cryIIA, and southern blot was determined the location of each gene on intact and enzyme-digested plasmid DNA fragments. Except for cryIA(a) gene on the high molecular weight plasmid of 165-kb, all of four genes were located on the plasmid of 66-kb. The production of $\beta$-exotoxin from B. thuringiensis NT0423 was identified by the HPLC analysis. In addition, the $\beta$-exotoxin showed its ability to prevent pupation of treated larvae of house flies (Musca domestica) from developing into normal adults.

• Journal of environmental and Sanitary engineering
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• v.9 no.1
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• pp.89-96
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• 1994

This report was investigate the biological characteristic of $\delta$-endotoxin of product by TH109 strain, one strain TH109 which has toxicity on Cockroach is isolate and identification. Generally the $\delta$-endotoxin of product by 3. thuringiensis strain was easily soluble in acid, alkaline and organic solvents but $\delta$-endotoxin of product by TH109 strain are insoluble in HCI, NaOH Thiol- reagent(25mM Dithiotheritol, 25mM Dithioeryritol, 25mM Nathioglycolate, 0.2M ESCN, 2% v/v $\beta$-mecaptethanol), organic solvents( acetone, $CCI_{4}$, ether, dioxin MeOH chloroforrh xylene ), Protease. Through this study of $\delta$-endotoxin produced by TH109 strain is insoluble in acid, alkaline, organic solvents and pretense etc. In the point of view, it is greater possibility that $\delta$-endotoxin will be transform into toxin by the reducible materials instead of the reaction of protease in the intestine.

• Microbiology and Biotechnology Letters
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• v.22 no.3
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• pp.227-232
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• 1994

In order to microbially control root-knot nematode(Meloidogyne incognita) in tomato, a strain BtTH109 of Bacillus thuringiensis producing root-knot nematocidal toxin was isolated. The strain BtTH109 was identified B. thuringiensis subsp. indiana(serotype 16) based on flagella antigenicity, biochemical properties, and morphological charcateristics. The strain BtTH109 have extracellularly produced a root-knot nematocidal toxin, which was very toxic against not only egghatch but also the 2nd-nematode larva of root-knot nematode in vitro.

• Korean Journal of Agricultural Science
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• v.41 no.4
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• pp.351-359
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• 2014

For identifying the plasmid DNA coding cry gene of Bacillus thuringiensis subsp. aizawai KB098 with high insecticidal activity against Spodoptera exigua, mutant isolates with no crystal protein were produced by $42^{\circ}C$ incubation condition and then mutant plasmid DNA band patterns were compared with those of KB098. KB098 isolates had 4 cry genes, cry1Aa, cry1Ab, cry1C, cry1D, and also had been found seven plasmid DNA. Though the SDS-PAGE experiment, it was confirmed that mutant didn't produce 130~145kDa protein band involved in bipyramidal shape crystal. Also, five mutant isolates had no cry genes coding plasmid DNA in PCR. In result of comparison the plasmid DNA of KB098 and 5 mutant isolates, only 1 plasmid DNA band was left out in mutant plasmid DNA pattern, so that the missing band was extracted from the gel. The missing(disappeared) plasmid DNA was the largest molecular size among the 7 plasmid DNA of KB098 and it was also confirmed this plasmid DNA had all 4 cry genes through PCR.

• Korean journal of applied entomology
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• v.48 no.4
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• pp.519-526
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• 2009

Bacillus thuringiensis subsp. kurstaki KB100 isolated from the domestic soil have the most effective activity against the beet armyworm, Spodoptera exigua larva. The tannic acid as protease inhibitor might be increased the efficacy of sublethal concentrations of B. thuringiensis. The tannic acid was identified as a protease inhibitor that could increased the efficacy of sublethal concentrations of B. thuringiensis. Mixture of B. thuringiensis and tannic acid was investigated the mortality of S. exigua larva in the laboratory and field. When B. thuringiensis treated to 2nd larva of S. exigua, mortality was shown 54.4%. However, mixtures of B. thuringiensis with 4 and 40 mM tannic acid were increased mortalities to 2nd larva of S. exigua as 64.0 and 95.5%, respectively. Also, synergy effect of mixture of B. thuringiensis and 40 mM tannic acid was increased the mortality of S. exigua 3rd larva to 93.3%, even though 60.0% mortality with only B. thuringiensis treatment. On the other hand, the mortality of mixture with B. thuringiensis and 80 mM tannic acid was 53.3% lower than B. thuringiensis single treatment. In the welsh onion field, the accumulated mortalities of 3 times replicated with mixture of B. thuringiensis and 40 mM tannic acid were 83.9, 89.4 and 66.8% compare with 61.8, 80.4 and 47.3% as only B. thuringiensis treatment, respectively.

• International Journal of Industrial Entomology and Biomaterials
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• v.1 no.2
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• pp.123-129
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• 2000

Expression of the crylAcl gene of an acrystalliferous Bacillus thuringiensis strain under the control of the native or $\alpha$-amylase gene promoter was investigated. The crylAcl gene was cloned in a B. thuringiensis - E. coli shutle vector, pHT3101, undder the control of either the native promoter (pProAc) or the $\alpha$-amylase promoter from Bacillus subtilis (pAmyAc). These two recombinant plasmids were successfully expressed in B. thuringiensis subsp. kurstaki Cry B. The first transformant (ProAc/CB), harboring pProAc, expressed an about 130 kDa protein begining 24 hr after inoculations just as in the case of the wild type of B. thuringiensis subsp. kurstaki HD-73. The second pAmyAc-transformant (AmyAc/CB) began to express the gene just 6 hr after inoculation, but Western analysis showed that the activity of the $\alpha$-amylase promoter was relatively weaker than that of the native promoter. As expected, their toxicity against Plutella xylostella larvae was dependent on the amount of Cry1Acl protein expressed.

• International Journal of Industrial Entomology and Biomaterials
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• v.3 no.1
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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.

• Journal of Life Science
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• v.12 no.3
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• pp.369-373
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• 2002

The waste-water from the industry for production of a soybean curd (the soybean curd waste-water) was investigated to use for the substrate to produce the endotoxin of Bacillus thuringiensis subsp. kurstaki HD-1 used as one of well known microbial pesticides. The pH of the soybean curd waste-water was 9.8 and its chemical oxygen demand (COD), total nitrogen (TN) and phosphate (TP) were 276.0, 71.1 and 5.5mg/$\ell$, respectively. The higher was the concentration of the soybean curd waste-water in the medium, the more endotoxin was produced. Maximal sporulation occurred at which concentration of $K_2$HPO$_4$in the medium supplied with the soybean curd waste-water was 1% (w/v). Production of the endotoxin with the optimized medium supplied with the soybean curd waste-water was 1.5 times higher than that without the soybean curd waste-water. The soybean curd waste-water was found to be suitable substrate for production of the endotoxin of Bacillus thuringiensis subsp. kurstaki HD-1.

• Korean journal of applied entomology
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• v.47 no.1
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• pp.87-93
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• 2008

Bacillus thuringiensis with selected high toxicities against tobacco cutworm, Spodoptera litura were isolated from domestic soils. When being observed under a phase-contrast microscope, the insecticidal crystal proteins were showed a bipyramidal crystal types. New CAB 109 isolate was identified to B. thuringiensis subsp. aizawai in the H serotype. As a results of insecticidal activities between CAB 109 isolate and 3 existing ready-made products against 3rd larva of S. litura, CAB 109 isolate showed 100% mortality with spore concentration $(1.3{\times}10^7cfu/ml)$. It was a very high insecticidal activity compared with a existing ready-made B. t. products. $LD_{50}$ values of CAB 109 isolate was $9.78{\times}10^5,\;6.87{\times}10^6\;and\;1.83{\times}10^7cfu/ml$ spore concentration against 2nd, 3rd and 4th larva of S. litura, respectively. Unlike Plutella xylostella, S. litura was slowly died after application up to 7 days. The weight of S. litura larva applied with CAB 109 isolate were 6-7 times less than controlled group. Even though it didn't die, it did not grow into next larva. The result observed with scanning electron microscope was that CAB 109 isolate of B. t. aizawai formed a typical bipyramidal crystal protein type. Otherwise, when CAB 109 isolate was examined with SDS-PAGE and with trypsin, there was no difference between CAB 109 strain and ready-made products of B. thuringiensis.