Barbara Grytner-Zięcina

Ultrastructural and cytochemical studies on vitellogenesis in trypanorhynch cestode Dollfusiella spinulifera Beveridge, Neifar et Euzet, 2004 (Eutetrarhynchidae)

The first description of vitellogenesis in the Trypanorhyncha is presented in this paper. Though the type of vitellogenesis and mature vitellocyte in Dollfusiella spinulifera appear to be unique among the Eucestoda, to some extent they resemble that observed in the lower cestodes, namely the Tetraphyllidea and Pseudophyllidea. Maturation is characterized by: (1) an increase in cell volume; (2) extensive development of large, parallel, frequently concentric cisternae of GER that produce proteinaceous granules; (3) development of Golgi complexes engaged in packaging this material; (4) continuous enlargement of proteinaceous granules within vesicles and their transformation into shell globule clusters; and (5) progressive fusion of all vesicles, with flocculent material containing the proteinaceous granules and shell globule clusters, into a single very large vesicle that characterises mature vitellocytes of this tapeworm. Cell inclusions in and around the large vesicle consist of flocculent material of a very low density, a few shell globule clusters, moderately dense proteinaceous granules and numerous large droplets of unsaturated lipids. A new previously unreported mode of transformation of proteinaceous granules into shell globule clusters, that evidently differs from that of pseudophyllideans and tetraphyllideans, is described. Cytochemical staining with periodic acid-thiosemicarbazide-silver proteinate for polysaccharides indicates a strongly positive reaction for membrane-bound glycoproteins in all membranous structures such as GER, mitochondria, Golgi complexes, nuclear and cell plasma membranes. Similar staining revealed β-glycogen particles scattered in the cytoplasm of maturing vitellocytes. Typical cytoplasmic β-glycogen particles appear mainly during early vitellocyte maturation but it is characteristic for this species that they are only seldom visible in mature cells. Some working hypotheses concerning the interrelationship between this particular pattern of vitellogensis, possible mode of egg formation in D. spinulifera, its embryonic development and trypanorhynchean life cycle, are drawn and discussed.

Ultrastructure of vitellocytes in the cestode Progrillotia pastinacae Dollfus, 1946 (Trypanorhyncha, Progrillotiidae)

The present study describes the ultrastructure of mature vitellocytes of the trypanorhynch cestode Progrillotia pastinacae Dollfus, 1946 (Progrillotiidae), a parasite of the common stingray Dasyatis pastinaca (Linnaeus, 1758) (Dasyatidae). The vitelline cells of this species measure about 24 μm in length and about 20 μm in width. They have small, elongated, slightly lobulated nuclei, about 4–5 μm in length, with large dense elongated nucleoli and numerous irregularly-shaped dense clumps of heterochromatin. The extensive cytoplasm is rich in numerous cell organelles and cell inclusions. While the perinuclear cytoplasm contains numerous long parallel cisternae of GER, ribo-and polyribosomes, several Golgi complexes and mitochondria, the peripheral cytoplasm contains predominantly three types of cell inclusions: a great number of large lipid droplets, several shell globule clusters, and a very small amount of glycogen-like particles. The most characteristic features of vitellocytes in P. pastinacae are having almost no traces of glycogen and the great number of large, highly osmiophobic lipid droplets representing saturated fatty acids. The presence of large amounts of lipids also in two other trypanorhynchs, Grillotia erinaceus (Beneden, 1858) Guiart, 1927 and Dollfusiella spinulifera (Beveridge et Jones, 2000) Beveridge, Neifar et Euzet, 2004, is in strong contrast to the condition in the most evolved cestodes, Cyclophyllidea, that usually show no trace of lipids.

Post-embryonic development and ultrastructural characteristics of the polycephalic larva of Taenia parva Baer, 1926 (Cyclophyllidea, Taeniidae)

Post-embryonic development and fully-formed polycephalic larvae of Taenia parva Baer, 1926 were examined by light (LM) and transmission electron microscopy (TEM). Three developmental stages were recognised: (1) an early stage of exogenous budding at the surface of the central vesicle; (2) a stage of polycephalic cyst development accompanied by segmentation of the growing larval strobile and an obvious decrease in the size of the central vesicle; (3) fully-formed larval strobile and invaginated scoleces. In fully-developed encysted polycephalic larvae, there are usually 14–24 segmented larval strobilae, each terminating with an invaginated scolex; larval strobilae arise from a common central vesicle and remain attached posterior to it during the entire development. The number of segments varies between 109 and 120 per larval strobila. The polycephalic larvae examined closely resemble the strobilocercus type of taeniid larvae. The structure of developing and fully-formed larvae was examined by TEM. The tegument, scolex, subtegumental musculature of the strobilar segments, protonephridial system, calcareous corpuscles and medullary parenchyma of larvae exhibit general similarity with the same structures in adults at both LM and TEM levels. The morphogenesis of the larva of T. parva is compared with that of the polycephalic larvae of other Taenia spp. (T. krepkogorski, T. twitchelli and T. endothoracica) and with other asexually-multiplying cestode larvae (mesocestoidids, hymenolepidids and dilepidids).

Hymenolepis diminuta: experimental studies on the antioxidant system with short and long term infection periods in the rats.

Many helminths cause long-lasting infections, living for several years in mammalian hosts reflecting a well balanced coexistence between host and parasite. There are many possible explanations as to how they can survive for lengthy periods. One possibility is their antioxidant systems, which can serve as defence mechanisms against host-generated oxygen radicals. Therefore, the aim of this experimental study was to examine the antioxidant system in Hymenolepisdiminuta during short (1.5 months young tapeworms) and long (1.5 years old tapeworms) term infection in the rat small intestine. The strobilae of H. diminuta tapeworms (14 young and three old) were divided into three pieces: the anterior part, containing the genital primordiae in the immature segments; the medial part, containing the early uterus in the mature, hermaphroditic proglottids and the terminal part with the mature gravid uterus in the gravid segments. Supernatants of these fragments were used for determination of markers of oxidative stress: concentration of thiobarbiturate reactive substances (TBARS) and of reduced glutathione (GSH), and the activity of antioxidant enzymes: superoxide dismutase (SOD1 and SOD2), catalase (CAT), glutathione peroxidases (GSHPxs), glutathione transferase (GST) and glutathione reductase (GSHR). The results indicated changes in levels of oxidative stress markers and antioxidant enzyme activity in both the young and old forms of H. diminuta. Relatively high activity of SOD (particularly in the anterior part of young tapeworms) was observed, as was increased activity of total GSHPx and a relatively high concentration of GSH in all parts of the tapeworms. These are caused by exposure to increased amount of ROS, which are produced during the inflammatory state. Due to the high activity of antioxidant enzymes, the anterior section of young and old tapeworms is equipped with a very effective antioxidant system. Old organisms also effectively resist oxidative stress due to reduced levels of lipid peroxidation and the high activity of GST, all of which suggest good adaptation to the hostile environment in the hosts intestine.

Enzymatic antioxidant system in the cestode Hymenolepis diminuta after chronic infection of the rat

BackgroundThe aim of the present paper was to describe the enzymatic antioxidant system in Hymenolepis diminuta collected from rats exposed to chronic cestode invasion.MethodologyWe dissected different tissues of H. diminuta (immature proglottids, genital primordia, hermaphroditic proglottids, early uterus, and gravid uterus) and studied activity of: superoxide dismutases (SOD1 and SOD2), catalase (CAT), glutathione peroxidases (non-Se-dependent GSHPx and Se-dependent GSHPx), glutathione-S-transferase (GST) and glutathione reductase (GSHR), and oxidative stress markers — reduced glutathione (GSH), and the lipid peroxidation level (TBARS).ResultsWe demonstrated changes in antioxidant enzyme activities and levels of oxidative stress markers in different tissues of the parasite. The levels of TBARS and GSH indicate that oxidative stress occurred in tissues located proximal to the intestine wall. Activity of SOD1 was high in all parts of H. diminuta, but the GST activity was the highest of all studied antioxidant enzymes. SOD2 activity differed significantly in various parts of H. diminuta. Significant differences were observed for nonSeGSHPx and activity of other GSH-dependent enzymes was generally similar in all the tissues.ConclusionsOur results show that the enzymatic antioxidant system of H. diminuta, allows the parasite to adapt and live under conditions of chronic oxidative stress. It suggests an oxidative-antioxidative balance during interactions between parasite and host.

Demodex mite infestation in patients with and without rheumatoid arthritis

In the present study we compared the prevalence of Demodex mites in patients with rheumatoid arthritis and in one control group involving individuals of similar mean age. From each person we epilated 3–4 lashes from each eyelid and examined them under a microscope to find Demodex mites. In total 147 patients were examined. The prevalence of Demodex mites was 33% in rheumatoid arthritis (RA) patients and 31% in the control group. Our results demonstrated that the prevalence of Demodex mites was similar in RA patients as compared to the control group.

Changes of enzymatic antioxidant system in the small intestine of rats after the chronic invasion by Hymenolepis diminuta (Cestoda, Hymenolepididae)

SummaryThe aim of this study was to evaluate changes in the enzymatic antioxidant system in rat small intestine caused by invasion of tapeworms Hymenolepis diminuta. The study material consisted of samples of the rats small intestine after short- (1.5-months) and long-term (1.5-years) larvae invasion of tapeworm H. diminuta. In tissue extracts the concentration of oxidative stress markers (GSH and TBARS) and activity of antioxidant enzymes (SOD, CAT, total GSHPx, SeGSHPx, GST and GSHR) were determined. Changes demonstrated for GSH and TBARS level and the activity of antioxidant enzymes in the small intestine in rats indicate the induction of oxidative stress and weakening of antioxidant defense mechanisms, after both short- and long-term invasion of H. diminuta tapeworms. Observed profile of antioxidant enzymes activity in the small intestine of rats after prolonged exposure to direct or indirect contact with H. diminuta tapeworms points to the adaptation of the definitive host to oxidative stress and defense against parasitic invasions.

TEM studies on morphological “junctions” between Trichinella spiralis larvae and mouse skeletal muscle cells with particular emphasis on the early changes in host muscles

Larvae of the parasitic nematode Trichinella spiralis migrate via the bloodstream or the lymphatic system to the skeletal muscle cells where they induce multiple alterations in the intracellular environment leading to the formation of nurse cells. The “nurse cell-T. spiralis larva” complex is composed of a transformed fragment of a skeletal muscle cell and the wall of the larva. The pathological process responsible for the formation of this complex, known as basophilic transformation, is essential for the development of T. spiralis larvae, but it still not known how newborn larvae penetrate the transformed fragment of the muscle cell. In this study, we aimed to characterize the ultrastructure of the region of the nurse cell in direct contact with the larval wall, after one and two weeks of T. spiralis infection in mice. For this purpose, a transmission electron microscope fitted with a goniometer was used to make observations of samples tilted at an angle of ±40° relative to the axis of the electron beam. Examination of electron micrographs revealed the continuity of the nurse cell membrane adjacent to the larval surface and the presence of a large quantity of glycogen particles close to the inner surface of this membrane. Our results showed that death of the T. spiralis larvae was associated with destruction of the contact region between the larval wall and the adjacent surface of the nurse cell. We conclude that the T. spiralis larva does not penetrate the nurse cell, but a morphological “junction” is formed between the larval wall and the cell membrane.