摘要
无鞭毛体呈椭圆形,后部有深杯样表膜凹陷,虫体一侧有一小突起。膜下微管数为74—90个。细胞核有1—3个核仁,细胞质内充满核糖体,动基体大小不一,多呈腊肠形,由动基体延伸形成长袋状线粒体。靠近鞭毛袋一侧有一组4个游离微管,鞭毛轴丝为9+2结构,并具有基板_1和基板_2结构,基体为9组三联微管。 无鞭毛体分裂从新鞭毛轴丝形成和动基体DNA纤丝伸长开始,以后DNA纤丝带出现裂隙,继之核仁裂碎、消失,形成核内纺锤体,开始细胞核的分裂,随后虫体一侧表膜出现凹陷,新膜下微管和表膜先后形成,并从此处向细胞内伸入,最后完全包绕两个分裂的虫体,完成细胞分裂。随着虫体的发育繁殖,含虫空泡涨大,电子致密度变低。分裂后的无鞭毛体贴附到含虫空泡膜,并向巨噬细胞细胞质内移动,最后离开原来的含虫空泡,形成新的含虫空泡。
The morphology and division process of amastigotes of Leishmania donovani in vivo was examined by electron microscope.The amastigotes appear rounded or oval-shaped. Many osmiophilic bodies adhere to inner membrane of the phagolysosome and are within it. The amastigotes show a deep cut-like invagination and a small projection. The number of subpellicular microtubules present between 74-90. There ate 1-3 nucleoli in the nucleus. Through the section of the coiled filamentous structure kinetoplast shows sausage-shaped. There may be a mitochondrion extending by kinetoplast in amastigote. The mitochondrion in some amastigotes shows a large electron dense body and becomes large. The flagellum-associated microtubules are parallel to and close to one side of the flagellar pocket and connect with it. The axoneme is a complex strucr ture with the usual 9+2 set of fibrils. The axoneme show two basal plates (B1 and Bi) which are separated by a transitional zone without the central doublet tubules. The basal body of axoneme involves a circle of peripheral triplets without central tubules. Large units, ovoid ill shape, containing numerous small electron dense bodies are surrounded by a double-laminated layer. Golgi apparatus, endoplasmic reticulum, electron dense body, lysosome and ribosome are present in the cytoplasm of amastigotes.The division of amastigotes is started by the formation of new axoneme and extension of the coiled filaments of kinetoplast. At the same time the splitting of DNA fibrils was observed. The nuclcoli break into four pieces and then disappear. Intranuclear spindle occurs in the nucleus and later divides into two. Afterwards new subpellicular microtubules and pellicles appear successively and extend to the cytoplasm of amastigote. Finally the parasite is enclosed by the new subpellicular microtubules and pellicles and divides into two bodies.Following the development and division of the parasites, the host-cell phagolysosomes are greatly distended and the degree of their electron-dense decreases. Some of the newly formed amastigotes are free in the phagolysosomes which may contain several parasites. Then the newly formed amastigotes gradually attach to the phagolysosome membrane and move into the cytoplasm of macrophage. Finally the phagolysosome membrane gradually encloses the parasites which have left the original vacuoles. Many new phagolysosomes appear in the macropha-
出处
《动物学报》
SCIE
CAS
CSCD
1989年第3期233-237,共5页
ACTA ZOOLOGICA SINICA
关键词
利什曼原虫
无鞭毛体
形态学
Leishmania donovani, Amastigote, Phagolysosome, Electron microscope.
