蚊幼虫感染苏云金杆菌以色列变种后病理的研究

本文用电子显微镜、蛋白质凝胶电泳和蛋白水解酶测定的方法,比较研究了三种蚊幼虫在感染苏云金杆菌以色列变种后中肠组织的病变,经苏云金杆菌以色列变种处理10分钟后,中肠细胞的细胞器即呈现病变,最明显的是线粒体呈现极度的电子致密状态,细胞质的粗糙内质网也开始瓦解,处理16小时后,细胞核膨胀,各种细胞器进一步瓦解,而围食膜仍然完好。此时细胞的盐溶性蛋白含量减少,图谱上明显缺少一条蛋白区带。另方面,感染10分钟后,中肠的蛋白水解酶活性便下降,不同蚊种的酶活性相差比较大,幼虫中肠的蛋白水解酶主要为胰蛋白酶。 根据结果分析,我们初步认为,苏云金杆菌以色列变种,对蚊幼虫的毒效是苏云金杆菌以色列变种的毒素对中肠细胞能量代谢和中肠蛋白酶活性产生抑制的结果。

A PATHOLOGICAL STUDY ON MOSQUITO LARVAE TREATED WITH BACILLUS THURINGIENSIS VAR. ISRAELSNSIS

This paper deals with the pathological changes of the larvae of Aedes albopictus Skuse, Armigers subalbatus Walker and Culex fatigens Wiedemann treated with Bacillus thuringiensis var. israelensis .(B. t. i). It was observed that at ten minutes after the larvae were treated with B. t. i. pathological changes began to appear in the midguts. Observation under electron microscope showed that the mitochondria of the midgnt epithelial cells became "condensed", with the intraeristal spaces irregularly enlarged and the matrix highly electron dense. Most of the endoplasmic retieula lost ri-bosomes and their boundary lines bacame blurred. At 16 hours after the treatment the nuclei of the epithelial cells swelled and vacuoles appeared in the cytoplasm. However, the peritrophic membrane at this stage still remained intact. Biochemical analysis with Ar. subalbatus showed that the saline soluble proteins of the midgnt deercased in amount and one of the protein bands in the eloctrophoregram was lost. If was also revealed that in the larvae at ten minutes after being treated with B. t.i. the proteinase activity of the midgut deciline although the proteinase activities were different in the different mosquito species and mainly trypsin-like. The results of this work indicate that the toxin (toxins) of B. t. i. affects the energy metabolism and proteinase activity of the midgut epithelial cells of the mosquito larvae.