苏芸金杆菌广谱杀虫Tml3—14菌株晶体毒素及毒力特性

以新筛选的对鞘翅目，鳞翊目、双翅目均具毒性的B.t.Tml3-14菌株为材料，用HD-1、3370-1为参考菌株，比较了伴孢晶体蛋白的多肽组成，以及经三种昆虫肠道酶降解产生的抗酶多肽组分。SDS-PAGE分析表明：Tml3-14晶体蛋白含1 38kD、l 32kD主要成分和65kD次要我分。其晶体分别由三种昆虫肠道酶消化产生的毒性多肽，经生物测定，杀家蚕的毒性成分为68.5kD、59kD多肽；杀斜纹夜蛾毒性成分为71kD，67kD和59.6kD多肽；杀马铃薯瓢虫毒性成分为69kD、65kD多肽。它与HD01、3370-1晶体均有明显差异。

PROTEIN COMPONENTS AND TOXICITY OF DELTA. ENDOTOXIN CRYSTALS FROM BACILLUSTHURINGIENSIS Tm13-14

The protein components of the delta-endotoxin crystals from Bacillus thuringiensis HD-I (toxic to Lepidoptera), 3370-1 (nontoxic) and Tm13-14 (toxic to Lepidoptera, Diptera, and Coleoptera) were compared under the different lysated condition by SDS-PAGE. The results showed that Tm13-14 crystal contains two major peptides with MW 138 Kd, 132 Kd and a minor peptides of 65 Kd. The components of Tm13-14 crystal protein or its proteinase resistant peptides (PRPs) by gut juice of the three insect species tested are different from those of strain HD-1 and 3370-1. The toxic PRPs of Tm13-14, resulted from dissolving crystal by gut juice of three insect species, were purified by two steps, first by sephadex G-100 and thenby DEAE-52 chromatography. The results of bioassay and SDS-PAGE analysis suggested that the toxic PRPs to the larvae of Bornbyx mori were 68.5 and 59 Kd, to the larvae of Spodoptera litura were 71 Kd, 65 Kd and 59.6 Kd, to the larvae of Epilachna niponica were 69kD and 65 Kd. The LC50 values of intact crystal, the first purified toxic PRPs and 2nd purified toxic PRPs of Tm13-14 to the second instar larvae of E. niponica were 9.4, 4.1 and 3.2μg/ml respectively.