Kati Hatice, Sezen Kazim, Nalcacioglu Remziye, Demirbag Zihni
Department of Biology, Faculty of Arts and Sciences, Giresun University, Giresun, Turkey.
J Microbiol. 2007 Dec;45(6):553-7.
In order to detect and identify the most toxic Bacillus thuringiensis strains against pests, we isolated a B. thuringiensis strain (Bn1) from Balaninus nucum (Coleoptera: Curculionidae), the most damaging hazelnut pest. Bn1 was characterized via morphological, biochemical, and molecular techniques. The isolate was serotyped, and the results showed that Bn1 was the B. thuringiensis serovar, kurstaki (H3abc). The scanning electron microscopy indicated that Bn1 has crystals with cubic and bipyramidal shapes. The Polymerase Chain Reactions (PCRs) revealed the presence of the cry1 and cry2 genes. The presence of Cry1 and Cry2 proteins in the Bn1 isolate was confirmed via SDS-PAGE, at approximately 130 kDa and 65 kDa, respectively. The bioassays conducted to determine the insecticidal activity of the Bn1 isolate were conducted with four distinct insects, using spore-crystal mixtures. We noted that Bn1 has higher toxicity as compared with the standard B. thuringiensis subsp. kurstaki (HD-1). The highest observed mortality was 90% against Malacosoma neustria and Lymantria dispar larvae. Our results show that the B. thuringiensis isolate (Bn1) may prove valuable as a significant microbial control agent against lepidopteran pests.
为了检测和鉴定对害虫毒性最强的苏云金芽孢杆菌菌株，我们从危害最大的榛实象甲（鞘翅目：象甲科）中分离出一株苏云金芽孢杆菌菌株（Bn1）。通过形态学、生化和分子技术对Bn1进行了鉴定。对该分离株进行了血清分型，结果表明Bn1是苏云金芽孢杆菌库斯塔克亚种（H3abc）。扫描电子显微镜显示Bn1具有立方体形和双金字塔形的晶体。聚合酶链反应（PCR）揭示了cry1和cry2基因的存在。通过SDS-PAGE证实了Bn1分离株中存在Cry1和Cry2蛋白，其分子量分别约为130 kDa和65 kDa。使用芽孢-晶体混合物，对四种不同昆虫进行了生物测定，以确定Bn1分离株的杀虫活性。我们注意到，与标准的苏云金芽孢杆菌库斯塔克亚种（HD-1）相比，Bn1具有更高的毒性。观察到的最高死亡率是对舞毒蛾和舞毒蛾幼虫，为90%。我们的结果表明，苏云金芽孢杆菌分离株（Bn1）作为一种针对鳞翅目害虫的重要微生物控制剂可能具有重要价值。
