Ultrastructural studies on the integument of digenetic trematodes were investigated by several workers (Senft et al., 1961; Bjorkman and Thorsell, 1964; Burton, l966; Erasmus, l968; Morris and Threadgold, 1967, l968). Clonorchis sinensis is a common parasite of human beings in the Far East. But as far little has been written on ultrastructure of the integument of this parasite. This study was carried out systematically to elucidate the ultrastructure of the integument of adult C. sinensis, and the results are summarized as follows: The integument of C. sinensis was organized in two parts; the epidermis and the muscular layer. The apical surface and basal surface of the epidermis were covered with typical plasma membrane and irregularly invaginated from the surface. Plasma membrane at perisuckers was extremely folded and appeared as if the epidermis might be divided with the layer. The syncytial epidermis contained mitochondria and numerous secretory bodies, and which was connected by cytoplasmic processes to nucleated epidermal cells lying in the parenchyma. The mitochondriae, the secretory bodies, the granular endoplasmic reticulum, the Golgi bodies and the free ribosomes were present in the perinuclear cytoplasm of epidermal cells, but no organelle was observed in processes of epidermal cell except some secretory bodies. The fibrous layer consists of argentophile fiber and collagenous fiber, in which the circular muscle bundles and longitudinal muscle bundles were embedded. Bundles of muscle fiber are weIl developed at the perisucker, and mitochondriae in this portion contain many cristae as compared with any other parts of C. sinensis.
parasitology-helminth-trematoda-Clonorchis sinensis ; ultrastructure ; electronmicroscopy

The metabolism of Entamoeba histolytica would be affected by various environmental factors, and alteration of the environment was known to affect the fine structure of E. histolytica. The present study was designed electronmicroscopically to investigate the ultrastructure and enzyme activities in the axenic and conventional strains of E. histolytica. The trophozoites of axenically cultivated HK-9 strain and conventional YS-27 and YS-49 strains of E. histolytica were collected and fixed with 4 percent paraformaldehyde/0.1 M cacodylate buffer (pH 7.4). After washing them by centrifugation, 1 percent warm agar was added in the sediment. Solidified agar with the trophozoites was cut into 1 mm(3) cubes, and incubated in the various substrates to observe enzyme activities. Then, the specimen was post-fixed with 3 percent glutaraldehyde/0.1 M cacodylate buffer (pH 7.4) and 1 percent osmium tetroxide/0.1 M cacodylate buffer (pH 7.4), dehydrated in ascending ethanol series and embedded in epoxy resin. These were sectioned on an ultramicrotome and observed with a transmission electron microscope. The procedures for the observation of the fine structure were same as the above, except for the incubation in the substrate. The sections were stained with uranyl scetate and lead citrate. For the observation of the surface of the amoebae, scanning electron microscopy was carried out. The results obtained in the present study are summarized as follows: The fuzzy coat around double-layered plasma membrane of E. histolytica was more irregularly and densely distributed in the conventional strains (YS-27, YS-49 strains) than in the axenic strain (HK-9 strain). The endosomes, button bodies and chromatin material were surrounded by a double-layered nuclear membrane having scattered nuclear pores. The paranuclear body, mono- or double-layered vacuoles, vacuolar membrane whorls, rosette-like cylindrical bodies, aggregation of cylindrical bodies and helical bodies were found in the cytoplasm of the amoebae. Helical bodies and glycogen granules were generally abundant, while a few smooth endoplasmic reticula were observed in the cytoplasm. Alkaline phosphatase activity was mainly demonstrated in the plasma membrane, limiting membranes of vacuoles and smooth endoplasmic reticula. ATPase activity was observed in the nucleus, limiting membranes of vacuoles and vacuolar membrane whorls. Acid phosphatase activity was commonly demonstrated in the limiting membranes an contents of vacuoles, lysosome-like organelles, plasma membrane and the button bodies in the nucleus. The activity was more weakly demonstrated in the HK-9 strain than in the other conventional strains of E. histolytica. No peroxidase activity was observed in the amoeba strains employed in the present study. With a scanning electron microscope, no distinct structural differences were observed between the amoeba strains. All the trophozoite forms of the amoebae showed crater-like depressions and rugged features on the outer surface.
parasitology-protozoa ; Entamoeba histolytica ; electronmicroscopy ; alkaline phosphatase

An electron microscopic study was performed to know the basic tegumental structure of Cysticercus cellulosae. The scolex and bladder portions of cysticerci (human and porcine strains) were prepared for transmission and scanning electron microscopy by conventional procedures. In general, the tegument of C. cellulosae showed the basic ultrastructure of cestode tegument on electron micrographs. The teguments of both scolex and bladder portions consisted of such components i.e., an outer vesicular layer with numerous microtriches and inner fibrous layer. Below the fibrous layer, there were layers of muscle bundles and tegumental cells. The microtriches which covered the surface of cysticercus revealed two distinctly different shapes. The characteristic bladder-like, elongated pyramid shaped 'tetrahedral form' was observed on the surface of the scolex portion, whereas the elongated cylindrical 'filamentous form' was distributed on the surface of bladder portion. In spite of the difference of isolated host and location, the cysticerci showed the same result. But dimensional variations of the tegument according to topography of the worm were observed. The possibility of application in making differential diagnosis from other larval cestodes and possible functions of this larval tegument were discussed.
parasitology-helminth-cestoda ; Taenia solium ; cysticercus ; electronmicroscopy

Tegumental ultrastructures of Echinochasmus japonicus were observed by scanning electron microscopy. The worms were recovered from albino rats which were experimentally infected with the metacercariae obtained from Pseudorasbora parva. Followings are summarized findings. The worms were minute and plumpy gourd-shaped with attenuated anterior and round posterior end. The tegument of whole body was wrinkled transversely and covered with cobblestone-like cytoplasmic processes. Head crown was armed with 24 collar spines which were embedded in cytoplasmic pockets. The spines were arranged in a row with an interruption at dorsomedian line, however, the 2nd and the 4th spines were outstretched more than others. Oral and ventral suckers were muscular with numerous type II sensory papillae, and genital pore opened between the two suckers. Tegumental spines were spade-shaped with broad base and pointed tip. They were compact in ventro-lateral tegument or dorsal surface of anterior body. The were not found between the two suckers and dorsal surface of posterior body. Two types of sensory papillae, uni-ciliated (Type I) and roundly swollen sensory papillae (Type II), were observed. The type I papillae were chiefly distributed on ventral surface of tegument and type II were on the lips of suckers. Arrangement of collar spines, shape and distribution of tegumental spines or sensory papillae are regarded as characteristic features of E. japonicus.
parasitology-helminth-trematoda ; Echinochasmus japonicus ; electronmicroscopy

Spermatogenesis in liver flukes, C. sinensis, was investigated by using light and electron microscopes. The epithelium of the testis was composed of a basement membrane, numerous lamellae protuded from the membrance and large number of spermatogonia supported by the lamellae. The lumen of the testis was filled with numerous 8, 16 and 32-cell groups representing primary spermatocytes, secondary spermatocytes and spermatids respectively. None of cell groups with over 32 or under 8 cells was noticed. The process of spermatogenesis is presumably as follows; A cell group of 8 spermatogonia, attached together by a cytophore, is separated from the testis epithelium during the growth period, thus becoming primary spermatocytes. The primary spermatocytes divide to form a cell group of 16 secondary spermatocytes giving rise to a cell group of 32 spermatids through meiotic germ cell division. The spermatids begin to undergo a spermiogenesis. The newly formed sperms remain attached together in the lumen for a while before migrating through the vasa efferentia.
parasitology-helminth-trematoda ; Clonorchis sinensis ; spermatogenesis ; morphology ; electronmicroscopy

A morphological study on the ultrastructures of body wall and the nervous system of Clonorchis sinensis was conducted. For this study, liver flukes were collected from the liver of rabbit six months after the infection with metacercariae obtained from the fresh water fish, Pseudorasbora parva. The collected materials were washed with 0.85 percent saline solution and then immediately moved to cold 2.5 percent glutaraldehyde buffered with 0.1 M Millonig's phosphate buffer (pH 7.4). The materials were dissected into appropriate pieces in the fixative about 30 minutes after beginning of the fixation. Two hours later the materials were rinsed several times with the buffer and were fixed with cold, buffered 1 percent osmium tetroxide(OsO(4)) for 2 hours. The fully fixed tissue blocks were dehydrated in a series of graded concentrations of acetone and were embedded in Epon 812 mixture. Thin sections obtained from Sorvall MT-2 ultramicrotome were stained with uranyl acetate and Reynold's lead citrate. Observations of the sections were carried out with Hitachi HS-7S electron microscope. The following structures are newly identifed in a series of observations. The mid-abdominal integument of the fluke is more thicker(-6 micrometer) than the dorsal side(about 3 micrometer). Although it is so far known that only surface and epithelia of the suckers, pharynx, and the oesophagus are composed of integumental, anuclear layer, it is newly found that epithelium of the excretory pore also consists of integumental, anuclear layer. There are lot of microvilli in the dorsal outer surface of the oral sucker. A kind of ducts accumulated with unknown secretory granules are present within the parenchyrna around both of the oral suckers and the pharynx. The nerve endings are distributed to the integument of the body where sensory hairs are projected outward. The sensory hairs are rarely distributed throughout the whole integument, but a little more in the surroundings of both suckers. The sensory hairs are attached to the base of the sheath by a circular septate desmosome. No rootlet structure is observed but the upper part of the basal body is attached to the peripheral desmosome by transverse fibres. The mitochondria and the vesicles are present within the hair cavity. The nerve fibres are also found to be myelinated at least in main axons.
parasitology-helminth-trematoda ; Clonorchis sinensis ; electronmicroscopy ; mitochondria ; vesicle ; desmosome ; rabbit

The effect of praziquantel on P. westermani exposed in vitro was observed by stereomicroscope, light microscope and scanning electron microscope. Following results were found. The worms incubated in 0.01 micro-g/ml praziquantel were moving after 26-hour incubation. However, all of them were immobilized immediately after incubation in solutions over 0.1 micro-g/ml concentration. All of the exposed worms showed severe vacuolization not only in tegument but in subtegument, intestine, ovary, testis, Mehlis' gland and excretory bladder. Vacuoles in tegument burst out to form craters. As incubation time went on, tegumental structure was disintegrated severely. The worms exposed to praziquantel were observed to be immobilized and be vacuolized of all tissues. Disintegration of reproductive organs suggests that praziquantel have suppressive effect on egg production when the flukes are not killed. The drug effects were found more related with incubation time than with drug concentration.
parasitology-helminth-trematoda ; Paragonimus westermani ; electronmicroscopy ; chemotherapy ; praziquantel

A study on the ultrastructures of the prostate gland of Clonorchis sinensis was conducted. The presence of the prostate gland in this fluke has not been known up to present time. Authors observed the ejaculatory duct epithelium including its surrounding parenchyma and found the prostate gland with the help of the electron microscope. The prostate gland was consisted of numerous unicellular glands grouped around the ejaculatory duct. The individual cell was lobulated, tapering in the direction of the ejaculatory duct. The secreting ducts of the gland penetrated into the ejaculatory duct through the muscular layer and the basement membrane, and finally opened to the lumen of the ejaculatory duct. The secreting duct had single layered microtubules along the inner wall of the duct. The secretory bodies produced by the prostate gland seemed to be moved to the lumen of the ejaculatory duct through the secreting duct. The prostate gland of this fluke was less developed than that of Fasciola hepatica but the basic structures were quite similar. There were well-developed lamellae in the epithelia of all ducts concerning passage of spermatozoa from the testes to the male genital opening.
parasitology-helminth-trematoda ; Clonorchis sinensis ; electronmicroscopy ; prostatic gland ; rat ; liver

A transmission electron microscopic study was conducted in order to know basic tegumental structure of Cysticercus cellulosae which was obtained from the ventricles of human brain. In general, the electron microscopic appearance of the tegument resembled that of the body wall of adult and larval forms of other cestodes. The tegument both of the parenchymatous portion (scolex and spiral canal) and bladder portion consisted of such components , i.e., an outer vesicular layer with microtriches, and an inner fibrous layer. The subtegumental tissue below the fibrous layer was filled with muscle bundles and tegumental cells. The surface of the larva was covered by the microtriches of two distictly different types. The characteristic pyramid-shaped "tetrahedral" form was observed on the surface of the scolex portion, whereas the elongated, slender "filamentous" microtriches were distributed on the regions of the spiral canal and bladder portion. The tegumental and subtegumental tissues varied in thickenss from one region to the next. The possibility of application in making differential diagnosis from other larval cestodes and possible fuction of this larval tegument were discussed.
parasitology-helminth-cestoda ; Cysticercus celluosae ; Taenia solium ; tegument ; electronmicroscopy

This study was performed to observe the chronological changes in the tegumental structure of M. yokogawai using scanning electron microscope. The subjected worms were excysted metacercariae obtained from sweetfish, and 2-day, 1-week and 4-week old worms experimentally reared in albino rats. The results are as follows: The tegument of excysted metacercariae showed many transverse shallow rugae, which were more remarkable in posterior half body, i.e., posterior to ventral sucker. The whole surface was armed with many scale-like spines; 7-8 pointed ones on anterior body and 2-3 pointed on posterior body. The ciliated knob-like papillae (Type I) were abundant around oral and ventral suckers, which grouped 2, 3 or 4 in number in most cases. A few round swellings of tegument (Type II) were observed only on oral sucker. The tegumental surface of 2-day old worms showed deeper rugae, and the anterior half covered with knob-like processes of distal cytoplasm and the posterior half with cobblestone-like ones. Interspinous space became more wide and 9 pointed spines appeared on anterior dorsal surface. The sensory papillae enlarged but not changed in their distribution. The tegument of 1-week old worms revealed knob-like cytoplasmic processes in posterior half body and velvety ones around oral sucker. The scale-Iike spines of anterior half body changed remarkably to the slender ones of posterior body at the level of ventral sucker. In dorsal surface, the arrangement of the Type I papillae were bilaterally symmetrical. The tegument of 4-week old worms were finely differentiated and the posterior tegument covered with velvety cytoplasmic processes. The spines had remarkably grown in length and width but the density remained nearly unchanged. The papillae also became larger but their morphology and distribution were not different from younger worms. However, the round elevation of cytoplasmic ridges (Type III papilla) appeared bilaterally on inner wall of oral sucker, approximately 8 in number. From the above results, it is considered that the tegument of juvenile M. yokogawai continued to differentiate until 4 weeks after infection.
parasitology-helminth-trematoda ; Metagonimus yokogawai ; electronmicroscopy ; Plecoglossus altivelis ; tegument