Preferencje help
Polish version English version Język
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 3

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych:  Nile catfish
help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
1

Mode of attachment and histopathological effects of Macrogyrodactylus clarii, a monogenean gill parasite of the catfish Clarias gariepinus, with a report on host response

100%
Arafa S. Z., El-Naggar M. M., El-Abbassy S. A.
Acta Parasitologica
|
2009
|
tom 54
|
nr 2
103-112
A detailed account is given about the mode of attachment and histopathological effects of Macrogyrodactylus clarii Gussev, 1961, a viviparous monogenean from the gills of the catfish Clarias gariepinus. Most parasites attach their haptors to the proximal region of the gill filament (primary gill lamellae), while few specimens were seen attached to the distal region. Attachment of the haptor was achieved mainly by the blade of the hamuli, but no evidence was found indicating the participation of marginal hooklets in the attachment. The hamuli of M. clarii penetrate into the interlamellar epithelium of the gill tissue. Some evidences were found to indicate that M. clarii may also utilize suction force during haptoral attachment. The pathological effects of M. clarii are manifested by breakdown of the coating epithelium, necrosis of the epithelial cells, vacuolations inside and outside the host cells, fusion of the gill lamellae, rupture of blood capillaries, infiltration of erythrocytes and degeneration and fibrosis of the interlamellar epithelium. The host response includes the appearance of lymphocytes, mucoid secretions and hyperplasia of the tissue at the site of attachment.
2

Egg variability, hatching and anatomy of the oncomiracidia of three Quadriacanthus species [Monogenea] from the Nile Delta catfish, Clarias gariepinus

100%
Reda E. S., El-Naggar M. M., Arafa S. Z.
Acta Parasitologica
|
2003
|
tom 48
|
nr 4
An account has been given of the egg variability, egg development, egg hatching and behaviour and anatomy of the oncomiracidia of three species of the genus Quadriacanthus, monogeneans parasitizing the gills of the catfish Clarias gariepinus inhabiting Nile Delta waters in Egypt. Each of the three species of the genus Quadriacanthus produces eggs of different shapes and sizes. Quadriacanthus clariadis clariadis and Q. allobychowskiella produce four types of eggs while Q. aegypticus produces nine types of eggs. All types of eggs differ from each other in the presence or absence, size and shape of the appendages. It is suggested that eggs of different types are not genetically determined or functionally different. There is no significant increase in the egg size during incubation. Fluid-filled sacs are found only in the fully developed eggs of Q. c. clariadis and Q. aegypticus; they are absent from eggs of Q. allobychowskiella. It is suggested that opening of the operculum and emergence of the oncomiracidium are brought about by a mechanical, chemical and/or osmotic hatching mechanism. The glandular system of the oncomiracidia of the genus Quadriacanthus includes two anterior median head glands, at least six lateral head glands constituting the anterior adhesive apparatus and four posterior body glands. Two crescent-shaped sclerites, representing the precursors of the ventral hamuli, are present in the haptor of the oncomiracidium of Q. allobychowskiella but these sclerites were not observed in the oncomiracidia of Q. c. clariadis and Q. aegypticus.
3

Swimming in Gyrodactylus rysavyi [Monogenea, Gyrodactylidae] from the Nile catfish, Clarias gariepinus

80%
El-Naggar M. M., El-Naggar A. A., Kearn G. C.
Acta Parasitologica
|
2004
|
tom 49
|
nr 2
Gyrodactylus rysavyi, a monogenean parasite of the skin, fins and gills of the Nile catfish, Ciarias gariepinus, is capable of directional swimming when detached from the host and released in open water. The parasite propels itself by vigorously bending the body into a loop and then unbending the body with equal vigour. A typical Swimming phase lasts for 2-6 sec, involves between 4 and 8 looping/unlooping actions per sec and propels the parasite in any direction, including vertically upwards or downwards, at speeds of 1.7-5 mm/sec. The parasite is capable of swimming upwards for a distance of at least 15 cm. At the end of each swimming phase, the parasite sinks slowly, performing while it does so twisting and turning movements. The duration of this resting phase is similar to that of the swimming phase. A unique feature of the haptor of G. rysavyi is a posterior shift in the position of the 16 hooklets relative to the two large hamuli. The long handles of the hooklets radiate outwards, and like ribs support the fan-shaped posterior region of the haptor. This arrangement may be a specialization related to the adoption of looping and unlooping swimming movements, since the hooklet-supported fan is likely to provide most of the propulsion during swimming. Consideration is given to the possible role of swimming and the twisting and turning behaviour of the passively sinking parasite in the dispersal and transmission of G. rysavyi. The gyrodactylids Macrogyrodactylus congolensis and M. clarii, which also parasitize C. gariepinus, do not swim when detached from the substrate.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.