家蚕病原性微孢子虫SCM_8的研究  

Studied on A Microsporidium(SCM_8) Pathogenic for the Silkworm Bombyx mori

作　　者：潘敏慧[1] 万永继[1] 祝仁英[1] 

机构地区：[1]西南农业大学蚕桑丝绸学院,农业部蚕桑学重点开放实验室,重庆400716

出　　处：《蚕业科学》2002年第2期115-119,共5页ACTA SERICOLOGICA SINICA

基　　金：国家"九五"科技攻关专题 (96-616-0 2 -0 3 )部分内容

摘　　要：家蚕病原性微孢子虫SCM8的生活史单型 ,所有时期核不成对 ,发育周期为 9～ 10d。蚕体内发育的裂殖体生殖呈带状分裂 ,以多分裂的方式进行增殖 ,裂殖体近椭圆形 ,外被寄主细胞的内质网膜 ;母孢子以出芽方式进行原生质团的分割 ,形成多个单核孢子母细胞 ,孢子成熟不同步 ,孢囊内有几个至数十个孢子不等 ;SCM8孢子单核 ,卵圆形 ,大小介于SCM7(Endoreticulatusbombycis)和家蚕微孢子 (Nosemabombycis)之间 ,并随继代数的增加而趋小 ,到第 3代时大小稳定 ,与SCM7相近 ;成熟孢子的极膜层前部结构致密 ,后部结构相对疏松 ;孢子的极丝单列 ,9～ 10圈 ,极丝倾角为 4 2° ;后极泡圆形 ,较大。SCM8仅感染寄生家蚕的中肠上皮组织 ,具食下传染、无胚种传染能力 ,致病力较弱 ,感染中量 (IC50 )为 1 2 9× 10 5,病程 12d以上。SCM8的分类地位为微孢子虫门 ,单倍期纲 ,格留目 ,科、属暂未确定。In 1997,a microspordium pathogenic for the silkworm was isolated from the larvae for eggs production in Sichuan and named SCM 8.Under the electron microscope,the taxonomic data of SCM 8 were as fellows:(1) Parasite undergoes entire development within a vacole enveloped by the membrane resembling host endoplasmic reticulum.Envelope rather closed to parasite plasmalemma before sporulation,then became widely separated.Envelope was very delicate and most spores are free in smears of disrupted cells.(2)Nuclei unpaired in all stages.Large nucleus was observed in early stages.Proliferation by multiple division of paucinucleate moniliform.Early sporont was recognizable by the withdrawal of the sporont plasmalemma from the parasitophorous vacuole accompanied by an electron dense deposit on surface of the plasmalemma.Division into sporoblasts occurred by the pinching off of buds from the highly irregular sporont body,which produces several to about 60 sporoblasts.Sporoblasts mature into spores asynchronously,according to order of budding.(3) Spore is unincleate and ovoid.Its size becomes smaller as progress of generation.Polar filament was isofilar,singly coiled with about 9～10 turns.Posterior vacuole was clear.SCM 8 infected the epithelial cells of the midgut only.The pathogenicity of the spores was weak,with an IC 50 of 1.29×10 5 spores/mL.The course of pathogenesis lasted 12 days or more.SCM 8 was shown not to have the capacity of transovarial transmission.By searching of taxonomy of Microsporidia,the taxonomic status of SCM 8 is Microspora,Haplophasea Glugeida;Family and Genera are uncertain.

关 键 词：病原性微孢子虫SCM8 家蚕 生活史 分类 

分 类 号：S884[农业科学—特种经济动物饲养]