寄生于褐家鼠的肉孢子虫一新种(孢子纲,真球虫目)

A NEW SPECIES OF SARCOCYSTS (SPOROZOEA, EUCOCCIDIIDA) FROM RATTUS NORVEGICUS

描记于云南省安宁市褐家鼠Rattusnorvegicus肌肉内检获肉孢子虫1新种:左氏肉孢子虫Sarcocystiszuoisp .nov .。新种肌肉内的包囊乳白色,呈梭形,大小为10 5 8μm×117μm。包囊壁具有长指状突起,突起大小为10 0 μm×2 5 μm。透射电镜下,包囊壁突起在基部高度分枝,突起通过分枝的基部相互连接在一起。

The paper deals with a new species of sarcocysts from wild-caught Rattus norvegicus collected in Anning district, Yunnan Province, China. Measurements are in microns and were based on 7 specimens. Type specimens are deposited in the School of Life Science of Yunnan University in China.Sarcocystis zuoi sp. nov.(Figs.1-4) Intermediate host. Rattus norvegicus. Final host. Unknown. Infection rate: 6.3% (7/112). Locality. Anning District(25°24′N,102°35′E;1894m),Yunnan Province, China. Cysts. The spindle-shaped cysts in skeletal muscle (but not cardiac muscle) measured 1058μm×117μm. Cyst wall thick, striated with villi up to 10.0μm×2.5μm. Ultrastructures revealed that there was highly branched primary wall at the base of the protrusions. The protrusions connect each other at the branched base. There are minute invaginations over the surface of protrusions and primary cyst wall. Within the protrusions and the ground substance there is a lot of electron-dense granules, none of which contains fibrils. Zoites. Small, banana-shaped, up to 7.6μm×2.9μm. Type specimens. Formalin-fixed tissues containing cysts deposited with Zoological Specimen Room of School of Life Science of Yunnan University in China (accession Nos. R 2002015-2002020). Etymology. The specific epithet zuoi is derived from ZUO Yang-Xiang, one of highly effective explorers in sarcocyst research field in China. Six Sarcocystis species had been reported from Rattus norvegicus. At the light microscopical level, the six sarcocysts could be further characterized as those with a radiantly striated or smooth cyst wall. Sarcocystis singaporensis, S. villivil and S. murinotechis cysts possessed striated walls with a dimensions 5.4μm×1.5μm, 1.6μm×0.5μm and 6μm ×4μm, respectively. In S. singaporensis, a distinctive feature is the thick cyst wall with its large, stalked villi. Here, stalks and protrusions formed two distinct longitudinal layers. In S. villivil, electron micrographs of cysts showed that the villi extend from the surface of the cyst, with bottleneck-shaped, radiating microvilli that extended outwardly at varying intervals from the surface of the vill. Some of the microvilli appeared to form connections with the primary wall. In S. murinotechis, the cysts had short, broad protrusions with many invaginations but without necks. In S. zuoi, the cysts had long, finger-like protrusions, highly branched at the base of cyst wall. The protrusions connected each other at the branched base. This was a marked difference to among the other species where the highly branched cyst wall was not present.