中国水牛两种住肉孢子虫包囊超微结构的比较研究

A COMPARATIVE ULTRASTRUCTURAL STUDY ON THE TWO TYPES OF SARCOCYSTS IN CHINESE BUFFALOES

本文对采自我国湖南水牛食道肌的大、小两种住肉孢子虫包囊的超微结构进行了研究。两种包囊的细胞(母细胞和缓殖子)未发现有明显的结构区别,而包囊壁的结构则揭示出明显的差异。大包囊的原囊壁向表面皱褶形成菜椰花样的突起,突起内含纤丝,突起表面有凹陷;而小包囊的原囊壁皱褶形成长指形的突起,突起内不含纤丝,倒伏在包囊表面,突起壁是平滑的,无凹陷。这一观察表细:我国水牛体内的大包囊属于梭形住肉孢子虫,小包囊可能是枯氏住肉孢子虫。

The ultrastructure of the two types of sarcocysts, i.e. macrocysts ( 9.4× 2.3mm ) and microcysts ( 0.9× 0.017mm ) discovered in Chinese buffaloes, was studied by transmission electron microscopy. Material was collected from the eosophageal muscles of the naturally infected buffaloes in Hunan, China.Metrocytes and bradyzoites in both sarco-cysts appeared to have no marked differences in fine structures.The bradyzoites were banana-shaped and had 22 subpellicular microtubules, numerous micronemes, 8rhoptries,a micropore in the half of the body, one or two elongated mitochondria, and a nucleus. Other organelles included endoplasmic reticula,ribsomes,dense bodies, polysarccharide granules and membrane-bounded vesicles. Nevertheless,the ultrastructure of cyst walls revealed significant differences in both sarcocysts. The primary cyst wall of the macrocyst was folded into cauliflower-like protrusions, which contained fibrils; whereas that of the microcyst was folded into long finger-like protrusions, which never contained fibrils and appeared always lodged over the surface of the cyst. The wall of the protrusions was always smooth and had no invaginations as observed in the macrocyst. These findings suggest that the macrocysts belong to Sarcocystis fusiformis, and the microcysts might be Sarcocystis cruzi.