Eimeria jamescooki sp. n. was recovered from the skink Cryptoblepharus virgatus (Garman) found on the grounds of James Cook University, Townsville (type locality), North Queensland, Australia. Oocysts were 17.5-25.0 (22.1 ± 1.9) × 15-22.5 (17.7 ± 1.6) µm and sporocysts 6.25-10.0 (7.9 ± 1.15) × 3.75-6.25 (5.3 ± 1.0) µm in size. Endogenous stages are described from histological material examined by light microscope and by transmission electron microscope. Both merogony stages and gamonts were found to develop in the cytoplasm of the anterior gut mucosal epithelium. Meront progeny were comprised of 10 to 21 merozoites. Premature macrogamonts were elongate; some host cells contained two elongate macrogamonts. Unique to the presently described species were the Golgi ''plaques'' and an enclosure of tubuli. Mature macrogamonts and young oocysts ranged in size from 14 x 7 to 21 × 11 µm and contained two types of wall-forming bodies, canaliculi and amylopectin granules. Differentiating microgamonts conformed in fine structure with that observed in other eimerians. Their sizes increased from 15.4 × 4.2 to 28 × 8.4 µm while dividing to over 70 nuclei, which formed a corresponding yield of microgametes.
Adults of two coniopterygid species, Aleuropteryx juniperi Ohm, 1968 (Aleuropteryginae) and Semidalis aleyrodiformis (Stephens, 1836) (Coniopteryginae), were studied using scanning electron microscopy. Interspecific differences in the ultrastructure of the integument of all the major parts of the body were identified and described, and the functional and phylogenetic implications of the differences discussed. Additionally, the enlarged terminal segment of the labial palps of the Coniopterygidae and the Sisyridae, which up to now has been used as an argument for a sister-group relationship between these two families, was subjected to a thorough comparison. The very different morphology makes independent enlargement of the terminal palpal segment in both families plausible. This finding is congruent with the earlier hypothesis of a sister-group relationship between Coniopterygidae and the dilarid clade, which was proposed on the basis of molecular data, larval morphology and male genital sclerites. Finally, a new classification of the coniopterygid subfamilies is presented based on characters of the larval head (prominence of the ocular region, relative length of sucking stylets). The following relationship is hypothesized: (Brucheiserinae + Coniopteryginae) + Aleuropteryginae, and the implications of this hypothesis for the phylogenetic interpretation of the ultrastructural differences that we found are discussed: (1) The wax glands, as well as plicatures, are interpreted as belonging to the ground pattern of the family Coniopterygidae, and (2) the wax glands are considered to have been reduced in Brucheiserinae and the plicatures in Coniopteryginae. A distinct (though reduced) spiraculum 8 was detected in Semidalis aleyrodiformis; as a consequence the hypothesis that the loss of spiraculum 8 is an autapomorphy of Coniopteryginae is refuted.
The ultrastructural cytology and reproduction of Amphiacantha longa Caullery et Mesnil, 1914 is described. Mcrogonial reproduction was not observed. The sporogony follows two lines: free disporoblastic. and enveloped, polysporoblastic, involving sporoblast mother cells. The enveloped sporogony is endogenous in spore sacs of sporont origin, daughter cells are formed by vacuolation. Probably all stages have coupled nuclei. Both free and enveloped spores are equipped with an extrusion apparatus composed of a flat polar sac, a straight polar filament of manubrium type, and a posterior globular appendix. Manubrium and appendix are enclosed in a membraneous coat. Circular elements of coat material occur in the proximity of the extrusion apparatus. The membraneous coat and the surface layer of the manubrium penetrate the polar sac. The extrusion apparatus is located at the wide pole of the spore, the nuclei at the narrower pole. Hosts are gregarines of the genus Lecudina Mingazzini, living in the gut of the polychaete Lumbrinereis fragilis (O. F. Muller). The cytology and reproduction are discussed and compared to other genera of metchnikovellideans, to the chytridiopsid genera, and to microsporidia expressing the typical cytology for the group. Metchnikovellideans and chytridiopsids exhibit cytological and reproductive similarities. The species is redescribed, the diagnosis of the genus Amphiacantha Caullery et Mesnil, 1914 is emended, and the new family Amphiacanthidae, comprising the genera Amphiacantha and Amphiamblys Caullery et Mesnil, 1914, is established.
The anterior jejunum from common vole naturally infected with Giardia microti (Kofoid et Christiansen, 1915) was examined by ТЕМ and compared with the anterior jejunum from control (metronidazole-treated, Giardia-free) common voles (Pallas, 1778). Giardia microti infection resulted in significant diffuse shortening of microvilli and significant greater microvillous diameters. In addition, deformations of the microvilli were observed at the margin of the ventral disc. The microvilli attached to the lateral crest of the ventral disc were vesiculated with a disorganised filamentous core and contained whorled structures resembling “myelin-like figures”. The findings are discussed in context of the Giardia-epithelial cell interaction.
The ultrastructure and histochemistry of the tegument and penetration glands of adult Amphilina foliacea from the body cavity and the tissues of the internal organs of Acipenser ruthenus and A. stellatus were studied. New data on the localization in the tissue, development and in encapsulation of the adult A. foliacea mostly in the liver of A. ruthenus were obtained. The well developed penetration glands are necessary for penetration into the tissue and for migration of A. foliacea into the body cavity of the hosts. The tegument of the adult A. foliacea is a syncytium with cytons deeply embedded into the parenchyma. The secretory activity of the tegument of worms has a protective function against the immune system of the host. Our results give further information about the phylogeny of Amphilinidea and confirm the view of the close phylogenetic relationship of Amphilinidea and Cestoidea.
The oogonia and oocytes in the ovaries of Toxocara canis are joined to a cytoplasmic process called the rachis. The rachis is a muchbranched cytoplasmic mass without cell components in the germinal zone. At the end of the germinal zone and in the growth zone the cytoplasmic mass is formed into a central axial cylinder, containing small dense granules, lipid drops and glycogen. Throughout the growth zone shell granules similar to those present in the oocytes are also present in the rachis. Anterior to the opening of the ovaries into the oviduct the rachis disappears. The ovarian wall is composed of epithelial cells, adjoining the basal lamina. They are characterized by the presence of large numbers of mitochondria, especially in the germinal zone. The epithelial cells in the growth zone also contain rough endoplasmic reticulum, ribosomes and bundles of microfibrils. A dense tubular material occurs between the basal membrane of the epithelial cells and the basal lamina as well as in the wall intercellular spaces in the ovarian growth zone. Multivesicular labyrinthlike formations can also be observed in the epithelial intercellular spaces in the central portion of the T. canis ovary.
The fine structure of the oviduct, oviduct-uterine junction and uterus of the nematode Toxocara canis (Werner, 1782) is described. Columnar-type epithelioid cells with numerous microvilli at the apical membrane border the oviduct lumen. Many electron dense secretory products are present in these cells. The cells lining the oviduct-uterine junction have no microvilli. They are coated with an electron-dense layer and contain numerous membrane-bound dense material containing bodies. Externally, the cells are surrounded by a basal lamina and muscle cells. The epithelial cells lining the greater part of the paired uteri appear to be rather flat. The oocytes inside the oviduct are covered with a dense thick plasma membrane and contain lipid droplets, dense granules and glycogen. The morphology of the oocytes before the fertilization inside the oviduct-uterine junction resembles that of the oocyte in the oviduct. After the fertilization the egg shell formation takes place. The egg shell of T.canis is composed of four layers: uterine, vitelline, middle chitinous and inner layer. The differences between the fine structure of the egg shell of T. canis and other related nematodes are discussed.
Results of a study on trypanorhynch ccstodes of fishes from Indonesian coastal waters are presented. A new species, Dasyrhynchus thomasi sp. n., is described, and five species are recorded which all represent new locality records: Tentacularia coryphaenae Bose, 1797; Nyhelinia africana Dollfus, 1960; Nybelinia scoliodoni (Vijayalakshmi, Vijayalakshmi et Gangadharam, 1996); Sphyriocephalus dollfusi Bussieras et Aldrin, 1968; and Otobothrium penetrans Linton, 1907, Their known ranges of distribution are extended to the East-Indian Ocean. Scanning and transmission electron microscopy was used to clarify details of the tentacular armature and surface morphology of T. coryphaenae, D. thomasi and O. penetrans. In T. coryphaenae, hook-like microtriches along the bothridial tegument are embedded in the distal cytoplasm, sometimes showing a split base. The solid tentacular hooks are embedded into a fibrillar, highly ordered tentacular wall. D. thomasi is distinguished by its characteristically shaped bothridia and a triple chainette with winged hooks on the external surface of the tentacle. Tufts of microtrichcs with ciliated sensory receptors arc regularly arranged on the bothridial surface of O. penetrans. They show similarities to sensory receptors reported from other trypanorhynch cestodes. Otobothrium pephrikos Dollfus, 1969 is considered a junior synonym for O. penetrans, and the variability of the scolex within trypanorhynch cestodes is emphasised.
Genetic predisposition and social stress may represent important risk factors in etiology of hypertension associated with endothelial dysfunction. Perturbations of endothelial structural integrity are also critical for the pathogenesis of vascular diseases. We examined effect of chronic social stress on structure of aortic endothelium in bord erline hypertensive (BHR) and normotensive Wistar rats. Male BHR – offspring of Wistar mothers and SHR fathers and age-matched W were exposed to 6-week crowding stress (5 rats/cage, 200 cm2/rat). Aortic tissue was processed for electron microscopy and NO synthase activity measurement. Crowding stress significantly increased blood pressure in BHR compared to basal values (140±3 mm Hg vs. 130±3 mm Hg, p<0.05) and reduced enzyme activity by 37 % (p<0.01) in the aorta of BHR. Local slight structural alterations of endothelium were found in non-stressed BHR (p<0.001) when compared with Wistar rats. Chronic stress caused marked (p<0.005) subcellular injury of endothelial cells in aorta of BHR characterized by mitochondrial damage, presence of vacuoles, increased number of lysosomes, Weibel-Palade bodies, changes of intercellular connections and local disruption of endothelium, while only slight changes were seen in Wistar rats. Results suggest increased sensitivity of aortic endothelium of BHR to chronic crowding that may contribute to acceleration of arterial dysfunction., Ľ. Okruhlicová, K. Dlugošová, M. Mitašíková, I. Bernátová., and Obsahuje bibliografii a bibliografické odkazy
This paper describes the fine structure of oocysts of Nematopsis sp. (Apicomplexa, Porosporidae) found in the abductor muscles of seawater clams, Meretrix meretrix (Linnaeus, 1758) (Veneridae), collected near the city of Dammam (6°17'0''N, 50°12'0''E) in the Arabian Gulf off the coast of Saudi Arabia. Oocysts of an ellipsoidal shape were found among myofibrils of the abductor muscles of infected clams. Each oocyst is composed of an oocyst wall surrounding a single uninucleate vermiform sporozoite located in the lumen of the oocyst wall. The thin oocyst wall (0.70-0.85 µm thick) is composed of homogenous electron-lucent material formed by three layers of equal-thickness. The oocyst wall contains a plano-convex opercular-like structure about 2.5 µm in diameter and 0.75-0.90 µm thick, composed of a homogenous material with moderate electron density. The oocyst is of an ellipsoidal shape and is 15.6 ± 0.6 µm long and 11.1 ± 0.7 µm wide. Externally, the oocyst wall is surrounded by a complex dense network of numerous anastomosed microfibrils, which are attached to the oocyst wall, forming 2-3 layers and extending towards the periphery, at some points penetrating amongst the host cells. The myofibrils in some cases show evident aspects of lysis as a consequence of the appearance of lysosome-like vesicles. Lacking knowledge of a complete life cycle and/or molecular data precluded the conclusive identification of this species.