离体培养鼠疟原虫动合子形成过程的电子显微镜观察

本文报道了用透射电子显微镜观察离体培养的鼠疟原虫配子体到动合子的发育过程。 鼠疟原虫配子的发生是由嗜锇小体趋向配子体表面开始。雌配子体从红细胞中逸出后,嗜锇小体消失。雄配子体微管形成和鞭毛轴丝集合是从红细胞中逸出前出现的。合子转变为动合子由致密内膜及膜下微管形成时开始,继之形成顶端复合物,随着突起增大,表膜复合物逐渐向后延伸,最后包绕整个虫体,即完成动合子的发育。疟原虫生活史第一次核分裂可能发生在动合子形成期间。本文证实了离体培养的动合子与蚊体内发育的动合子结构相同。

ULTRASTRUCTURAL OBSERVATION ON THE OOKINETE FORMATION OF RODENT PLASMODIUM IN VITRO

Tkis work deals with ookinete formation of rodent phsmodium in vitro. The morphology of gametocyte, gamete, zygote and ookinete and the process of formation of ookinetes under electron microscope is as follows:1. Macrogametocyte and rnicrogametocyteThe macrogametocyte and microgametocyte are surrounded by a thin layer of host-cell cytoplasm. There are mitochondria, endoplasmic reticula, csmiophilic bodies, malarial pigments and some vacuoles in macrogametocyte. Many osmiophilic bodies, even more than 100, often get together. Mature macrogametocytes are full of granular ribosomes. The nucleus is composed of two layer membranes with a dense nucleolus.The nucleus of microgametocyte is obviously larger than that of macrogametocyte and is lobe-shaped with intranuclear body which adheres to inner membrane of nuclear envelope. There are two dense bodies on the pits of nuclear membrane. The cytoplasm of the microgametocyte contains few mitochondria and endoplasmic reticula.2. Activity of gametocyteThe onset of gametogenesis in macrogametocyte and microgametocyte is heralded by migration of the osmiophilic bodies towards the surface. These organelles may be involved in emergence of the gametocyte from the host cell. After emergence of the macrogametocyte from the , host cell the osmiophilic bodies obviously decrease and even disappear.In microgametocytes microtubule synthesis and axoneme assembly occur before departing from the host cell. The number of axoneme assemblies is at most 28. The 9 + 2 configuration of the axonemes is assembled in the normal manner. Abnormalities in axoneme development are common, giving numbers of central fibres from 0 to 6. The microtubules locate near the top of microgametes. It is electron dense near the top of microgamcte because there are some dense materials in it.3. The formation of ookineteIn the zygote cytoplasm of Plasmodium yoelii yoelii the endoplasmic reticula get longer and attach closely to the pellicle. The onset from zygote to ookinete is heralded by formation of pellicular complex. Subpellicular microtubules appear just beneath the pellicular complex.In the first place one side of zygote forms dense inner membranous layer (It originates from the endoplasmic reticulum.) and subpellicular microtubules. Near one end of pellicular complex a pk appears. The parasite projects outwards from here. The apical end of projection forms polar ring, canopy and subpellicular cavity. Following enlargement of the projection newly-formed dense inner membrane and subpellicular microtubules gradually extends bachkwards and finally enclosed the whole parasite. During the formation of ookinete nucleolus and intranuclear spindle present in the nucleus. This may explain that the first nuclear division of life cycle of plasmodium begins during the formation of ookinete.4. Mature ookineteThe ookinete is limited by a pellicular complex which is composed of outer membrane, inner membrane and subpellicukr microtubules. The apical end contains pplar ring, canopy and subpellicular cavity. Rhoptries, micrpnemes, mitochondria, endoplasmic reticulums and numerous ribosomes present in the cytoplasm of ookinete. Behind canopy and subpellicular cavity there are pellicular folds, with a number of 3, 4 and 5.