文献类型： 外文期刊

作者： Shu, C. ¹ ; Liu, R. ¹ ; Wang, R. ¹ ; Zhang, J. ² ; Feng, S.; Huang, D.; Song, F.;

作者机构： 1.Chinese Acad Agr Sci, Inst Plant Protect, State Key Lab Biol Plant Dis & Insect Pests, Beijing 100094, Peoples R China; Hebei Acad Agr & Forestry Sci, Inst Plant Protect, Baoding 071000, Peoples R China; Chinese Acad Agr Sci, Biotechnol Res Inst, Beijing 100081, Peoples R China; NE Agr Univ, Harbin 150030, Peoples R China

2.Chinese Acad Agr Sci, Inst Plant Protect, State Key Lab Biol Plant Dis & Insect Pests, Beijing 100094, Peoples R China; Hebei Acad Agr & Forestry Sci, Inst Plant Protect, Baoding 071000, Peoples R China; Chinese Acad Agr Sci, Biotechnol Res Inst, Beijing

期刊名称：CURRENT MICROBIOLOGY （ 影响因子：2.188； 五年影响因子：2.197 ）

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收录情况： SCI

摘要： The cry8C-type gene designated cry8Ca2, which was cloned and sequenced from a Bacillus thuringiensis isolate HBF-1 in China, consisted of an open reading frame of 3483 bp encoding a protein of 1160 amino-acid residues. Sequence analysis showed that the Cry8Ca2 protoxin of 130.5 kDa had 99.9% sequence homology with the previously reported Cry8Ca1 protein, with one mismatch between the two amino-acid sequences. When the Cry8Ca2 toxin was expressed in a crystal-negative strain of B. thuringiensis (HD-73-), elliptical crystals were produced. Cell extracts from this recombinant strain showed insecticidal activity against Anomala corpulenta larva. Mutant cry8Ca2 genes, produced by polymerase chain reaction amplification with Taq DNA polymerase, were used to develop recombinant B. thuringiensis strains. Mutants producing higher levels of insecticidal activity were identified by bioassay. Thirty-five mutants forming crystals were characterized, and two of them showed significantly increased insecticidal activity against A. corpulenta larva. The 50% lethality concentrations (LC) of the two mutants were 0.2334 x 10i and 0.2591 x 10i colony-forming units g-p#, considerably lower than the LC of the wild-type strain HBF-1 (0.9583 x 10i CFU g-p#) and that of B. thuringiensis serovar japonensis strain Buibui (1.0752 x 10i CFU g-p#).