我国蝗虫微孢子虫超微结构与致病特性研究

ULTRASTRUCTURE AND PATHOGENICITY OF A MICROSPORIDIAN FROM LOCUST IN CHINA

从我国东亚飞蝗上分离出微孢子虫病原物圆形裂殖体（Meront），除单核、双核和四核外，还在本菌株观察到六核、八核等多核裂殖体。超微结构生活史观察，裂殖体细胞质膜很薄，与寄主细胞紧密相接，其细胞内含许多核糖体、囊泡和大量光滑内质网、双核、四核裂殖体，均呈双核相伴排列，以及正进行细胞质分裂的裂殖体和产孢体（Sporont）；产孢体细胞壁加厚明显区别于裂殖体。整个生活史均为双核相伴排列。产孢体表面有多层电子致密物质呈短线条沉积。成熟孢子极膜层为指纹状片层结构，极丝圈18～20个。该病原物主要感染脂肪体和唾腺，并能引起寄生死亡，其死亡率有随接种剂量的增高而增大的趋势，而且3龄比4龄更敏感。接种后群体饲养比单头饲养死亡率高。病虫比健虫生育期延长2～3天，产卵能力下降，接种后24天病虫食物消耗比健虫减少35～75％。

The ultrastructure and development of a microspori dian,isolated from the dead body of ori ental migratory locust (Locusta migratoria manilensis) in Hebei province was observed under light-and electron-microscope. The meront was spherical or ovocylindrical containing uni-, bi-,quadri-and multinucle ate forms. The hexa-,eith-nucleate meronts measured 6. 9 ×7. 9μm were peculiar to this strain. The ultra strructure of stages in the life cycle of the mictosporidia showed that merontsdeveloped in direct contact with the host cell cytoplasm and bi-,guadrinucleates meronts were arrangment two nuclei in a diplokary on. Sporonts were differentiated from meronts with the thickened plasmalemma and observed undergoing cytokinesis. Stratified electron-dense strands were depostied in the host cell cytoplasm and sporont plas malemma surface.Studies of pathogenicity showed that the mortality increased as the dosage rised1the third-instar was more sUsceptible than that of the fourth;the mortality of locusts reard together was higher than reard sep arately;the develoment time of infected locusta were delayed 2~ 3 days ;the number of eggs infected lo custs decreased ;the food consumption of the infected was 35~ 75 % less than controlled after 24 days' inoc ulation.