A study on the fine structure of <i>Clonorchis sinensis</i>, a liver fluke II. The alimentary tract and the excretory system

, Jeong, Kye Heon; , Rim, Han Jong; , Kim, Woo Kap; , Kim, Chang Whan; , Yang, He Young

doi:1980.18.1.81

Korean J Parasito > Volume 18(1):1980 > Article

Original Article


Korean J Parasitol. 1980 Jun;18(1):81-92. English. Published online Mar 20, 1994. http://dx.doi.org/10.3347/kjp.1980.18.1.81
Copyright © 1980 by The Korean Society for Parasitology


A study on the fine structure of Clonorchis sinensis, a liver fluke II. The alimentary tract and the excretory system
Kye Heon Jeong,Han Jong Rim,Woo Kap Kim,Chang Whan Kim and He Young Yang
Department of Biology, Soon Chun Hyang College, Korea.
Department of Parasitology and Institute for Tropical Endemic Diseases, College of Medicine, Korea University, Korea.
Department of Biology, College of Science, Korea University, Korea.
Department of Biology, Soong Jun University, Korea.


Abstract
A morphological study on the ultrastructures of the alimentary tract and the excretory system of Clonorchis sinensis was conducted. The liver flukes were collected from rabbit liver six months after the experimental infection The worms were washed with 0.85 percent saline solution and immediately moved to cold 2.5 percent glutaraldehyde in 0.1 M phosphate buffer pH 7.4. The materials were dissected and fixed for two hours. The blocks were post-fixed in 1 percent osmium tetroxide. The blocks were embedded in Epon 812. Ultra thin sections were cut with Sovall MT-2 ultramicrotome and stained with uranyl acetate and lead citrate. Sections were then observed with Hitachi HS-7S electron microscope. The following results were obtained in a series of observations. The walls of oral cavity and esophagus comprised tegumental syncytium, basement membrane, loose connective tissue, muscular layer and parenchymal cells. The apical surface and the base of the syncytium were covered with a protoplasmic membrane for each forming numerous invaginations. Granular endoplasmic reticulum was developed in the epithelium of the oesophagus. The gastrodermis of Clonorchis sinensis comprised two types of cells in general. The first cell type was numerous one forming a single continuous layer of epithelial cells. Each of the cells had outfolded cytoplasm into the caecal lumen and lamellae along the cell surface. Among the above epithelial cells, no considerable differences in structure reflecting their functional states were identified. The second cell type was less differentiated in nature and lay within the gastrodermis above the basement membrane but not in contact with the caecal lumen, being overlapped by neighboring gastrodermal cells of the type described above. At this portion the gastrodermis seemed to be a pseudostratified epithelium. There were well-developed lamellae along the surface of epithelia of all canals or duct concerning evacuation. The excretory pore was 7.5 µm in diameter and dorso-terminally opended. The epithelium of the excretory pore, a syncytial layer, contained many microtubules unlike the other part of tegumental layer of this worm. The epithelium thickness of the excretory pore was very irregular(1.3-5.5 µm).

Figures


	Fig. 1 Tegumental layer of oral cavity. A lot of mitochondria(M) and discoidal granules(DG) are scattered all over the syncytium. Numerous vacuoles(Va) are situated above the basement membrane(BM). The bundles of circular muscles(CM) are located below the basement membrane. ×11,300


	Fig. 2 A part of the pharynx. The bulk of the pharynx is composed of muscle fibers and associated muscle cell protoplasm. The muscle fibers(Mu) are consisted of radial muscles attached at either end to the basement membrane(BM). ×6,800


	Fig. 3 Oesophageal tegument. It contains rich endoplasmic reticulum(ER) and mitochondria(M). In the lumen(Lu), a lots of particles of food stuffs are seen. ×13,100


	Fig. 4 Caecal lumen. The lumen is covered by lamellae of gastrodermal cells(GC) (arrowed, 0.3µm). P, Protoplasmic projection of the gastrodermal cell. ×13,500


	Fig. 5 General feature of gastrodermis. The cells with lamellae, a common cell type, have well developed endoplasmic reticulum(ER). The cisternae of the ER are usually voluminous. The two cells(U) lay within the gastrodermis above the basement membrane(BM) and not in contact with the caecal lumen. These are supposed to be partially differentiated cells. ×10,200


	Fig. 6 Flame cells. Three cross sectioned flame cells(FC) are neighboring in the terminal cell(TC) of the excretory canal. BC, Basal cell; C, Chamber of flame cell; Ci, Cilia. ×14,400


	Fig. 7 Sagital section through flame cell. The internal chamber(IC) of the flame cell does not directly communicate with the surrounding parenchyma. The ribs(Rb) of the flame cell form the so called weir membrane which form a complete sheath around the internal chamber. N, Nucleus; Ci, Cilia; EC, External chamber; IL, Internal leptotriches. ×11,300


	Fig. 8 Cross view of a bundle of cilia of the flame cell. This figure show honeycomb-like pattern by the ciliary membrane(CM; arrowed, 40 Å). ×54,900


	Fig. 9 Longitudinal view of excretory canal. The basement membrane evaginated into the parenchymal cell(Pa). Lamellae(L) are projected into the excretory canal(ECa) from the surface of the epithelium. ×4,500


	Fig. 10 Epithelial cell of the bladder wall. The portion with a big nucleus(N), about 7µm in diameter, is usually voluminous. BM, Basement membrane; Lu, Lumen; Pa, Parenchyma. ×5,700


	Fig. 11 Bladder and excretory duct. This shows the portion where the excretory duct(ED) meets the bladder(BL). The lamellae(L) are much longer than those of the excretory canal or duct. Pa, Parenchyma. ×4,500


	Fig. 12 Light micrograph of the bladder(Bl) and the excretory pore(EP). The pore is dorso-ventrally opened. VS, Ventral side; DS, Dorsal side. ×500


	Fig. 13 Cross view of excretory pore(EP). Many of excretory bodies(EB) are seen. The thickness of the tegumental, anuclear layer epithelium(EP) is variable and its surface is irregular. ×6,000


	Fig. 14 Epithelium of the excretory pore. This syncitial layer has many microtubules(MT), mitochondria(M) and rod shaped discoidal granules(DG). (a:12 Å; b:160 Å) ×12,500


	Fig. 15 Epithelial cell(EC) in the parenchyma. The cells protrude protoplasmic tubules(PT) toward the epithelium(Ep) of the excretory pore and finally have coonnectioin with it. ×4,500

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