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Lamellodiscus crampus sp. nov. (Monogenea, Diplectanidae) is described from the gills of Dentex maroccanus (Valenciennes) collected from the Gulf of Gabès (Tunisia) in the oriental part of Mediterranean Sea. The new species belongs to the “ignoratus” group (sensu Oliver 1987) characterized by a lamellodisc with complete lamellae and a “lyre” shaped male copulatory organ, and the “ignoratus” sensu stricto subgroup, characterized by a haptor with simple lateral dorsal bars, as proposed by Amine and Euzet (2005). Lamellodiscus crampus can be easily distinguished from all the congeneric species of the subgroup “ignoratus” by the presence, in the “lyre” male copulatory organ, of five spines in the distal portion on the axial side of the paired piece.
Allopodocotyle tunisiensis sp. nov. is described from the intestine of Solea aegyptiaca Chabanaud collected from the Gulf of Gabès in the Mediterranean Sea off Tunisia. The new species belongs to the group C of Allopodocotyle Pritchard, 1966 species (sensu Bray 1987). It differs from its congeners in this group by the shape of the seminal vesicle and the anterior extend of the vitellarium which varies between just posterior to the ventral sucker and anterior margin. A key to the Allopodocotyle species of group C is presented. The status of the genera Allopodocotyle and Macvicaria (Gibson and Bray 1982) are briefly discussed.
Forty five specimens of the short beaked garfish Belone svetovidovi, a rare belonid species largely confused with the garfish Belone belone from Tunisian coast Sea were examined for metazoan parasite. Nine metazoan parasites species were identified: one monogenean (Axine sp.), 4 digeneans (Lecithostaphylus retroflexus, Tergestia acanthocephala, Aponurus laguncula and Condylocotyla pilodora metacercaria), one copepod (Bomolochus bellones), one isopod (Irona nana), one acanthocephalan (Telosentis exiguus) and one nematod Hysterotylacium sp. Most of parasite species were new records for B. svetovidovi in Tunisia. In the parasite fauna of B. svetovidovi, digenean C. pilodora metacercaria was the most prevalent species (42%) followed by Monogenea Axine sp. (36%). The total length of the host did not influence parasitic infection in B. svetovidovi. The metazoan parasite composition of B. svetovidovi revealed great similarity than those of B. belone from Tunisia supporting same ecological behavior of both hosts.
Hypocreadium caputvadum sp. nov. (Digenea, Lepocreadiidae) is described from the intestine of Balistes capriscus Gmelin collected from the Gulf of Gabès (Tunisia) in the southern Mediterranean Sea. This new species can be distinguished by a combination of characteristics shared by no other described species of Hypocreadium Ozaki, 1936. These characteristics include the presence of a distinct anterior notch, the follicular vitellarium confluent in the forebody, the presence of a muscular sphincter at the level of the anterior third of the metraterm and the size and the position of the cirrus-sac.
Monocotyle was proposed by Taschenberg (1878) to accommodate M. myliobatis Taschenberg, 1878 from the gills of Myliobatis aquila (Linnaeus) caught at the Aquarium of the Zoological Station of Naples (Italy). There have been three descriptions of this species: the original one by Taschenberg (1878) and two which are incomplete by Perugia and Parona (1890) and Palombi (1942). Illustrations by these authors are poor and sometimes conflicting. We have rediscovered M. myliobatis on the gills of the type host Myliobatis aquila caught near Algiers, Tamentfoust (36°47′N, 3°12′E) (Algeria). We provide new illustrations of this monogenean, based on new specimens. We also redescribe the anatomy, with special attention to the male and female reproductive systems, and we provide additional data regarding the morphology, the number and arrangement of the septal sclerites of the haptor and the haptoral marginal papillae. We indicate the similarity between Monocotyle myliobatis and Monocotyle sp. Euzet et Maillard, 1967 collected from Pteromyleus bovinus, Geoffroy Saint Hillaire (Elasmobranchii, Myliobatidae) by J. Cadenat off Dakar (Senegal).
During vitellogenesis in Parachristianella trygonis Trypanorhyncha, Eutetrarhynchidae) we distinguished four stages: (1) gonial or stem cell stage; (2) early differentiation stage concentrated on protein synthetic activity and shell-globule formation; (3) advanced differentiation stage with main cell activity concentrated on carbohydrate synthesis (glycogenesis) and massive glycogen storage in the form of α-glycogen rosettes and β-glycogen particles; and finally (4) mature vitellocyte stage. Early vitellocyte maturation is characterised by: (1) an increase in cell volume; (2) extensive development of large, parallel cisternae of GER that produce proteinaceous granules; (3) development of Golgi complexes engaged in packaging this material; (4) continuous enlargement of proteinaceous granules within vacuoles and their transformation into shell-globule clusters composed of heterogeneous material. Cytochemical staining with periodic acid-thiosemicarbazide-silver proteinate for polysaccharides indicated a strongly positive reaction for the presence of α-glycogen rosettes and β-glycogen particles in the advanced stage of vitellocyte maturation. Both protein synthesis for shell-globule formation and carbohydrate synthesis or glycogenesis, important storage of nutritive reserves for the developing embryos, observed during cytodifferentiation of P. trygonis vitellocytes overlap in time to some extent. Mature vitelline cells are very rich in three types of cell inclusions accumulated in large amounts in their cytoplasm: (1) shell-globule clusters, playing an important role in egg-shell formation; (2) numerous large lipid droplets, as well as a high accumulation of lipid and α-glycogen rosettes and β-glycogen particles that undoubtedly represent important nutritive reserves for the developing embryos. Despite the fact that the type of vitellogenesis and ultrastructure of the mature vitellocyte in P. trygonis appears to differ to some extent from those of three other trypanorhynch species, its general pattern and ultrastructure greatly resembles those observed in other lower cestodes. Factors that may have contributed to the qualitative and quantitative variation in lipids during vitellogenesis among the four species of Trypanorhyncha, are identified and discussed.
The present study reports the levels of mercury and selenium in Sarpa salpa and Balistes capriscus collected along the coast of Mahdia and Sfax (Tunisia). The systems constituted by S. salpa and Robphildollfusium fractum and by B. capriscus and Neoapocreadium chabaudi were tested as potential bioindicators to monitor environmental Hg pollution in marine ecosystems. Mercury and selenium concentrations were assessed in kidney, liver and muscle of 51 S. salpa and of 45 B. capriscus as well as in their respective endoparasites R. fractum and N. chabaudi. The Se:Hg molar ratios were evaluated for both species across the study areas. Surprisingly, the Se:Hg molar ratio in B. capriscus muscle from Mahdia is significantly lower than in Sfax. Our results indicate that some parasites may also be implicated in the amount of Se and Hg available in tissues and therefore contribute to oscillations of the Se:Hg molar ratios. In the model involving the carnivorous species (B. capriscus), the 5.1-times higher levels of mercury in N. chabaudi than in B. capriscus muscle in Sfax enable this fluke to be a sensitive biomonitoring tool for Hg pollution. The present results confirm that the habitual consumption of S. salpa should not suppose any potential health risk for Tunisian people. On the other hand, the consumption of B. capriscus may be of concern and further monitoring is advisable, since the Hg average concentration in Mahdia was above the maximum allowed Hg concentration in the edible portion of fish fixed by the European Union.
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.
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.
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