Wyniki wyszukiwania

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Fine structure of the infective eggs of the dilepidid cestode Hepatocestus hepaticus [Baer, 1932], a parasite of shrews

100%

Swiderski Z., Tkach V. V., Vaucher C.

Acta Parasitologica

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2000

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tom 45

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nr 2

Ultrastructural characteristics of the eggs of the dilepidid cestode, Hepatocestus hepaticus, is described. The mature oncosphere is surrounded by three envelopes: (1) an outer envelope; (2) an inner envelope consisting of three layers - an extraembryophoral cytoplasmic layer, a thick, fibrillar, low electron-dense embryophore, and intraembryophoral cytoplasmic layer, (3) a thin oncospheral membrane, surrounding the oncosphere. The whole surface of the oncosphere is covered by the cytoplasmic oncospheral tegument with numerous short microvilli and a layer of subtegumental somatic muscles. The following cell types were distinguished in the mature oncospheres: the U-shaped penetration gland a containing a large amount of tightly packed secretory granules; bi-nucleate perikaryon of the oncospheral tegument; somatic cells (= myocytons of somatic and hook muscles); and the germinative cells. The hook-muscle system consists of three pairs of embryonic hooks and a complex system of specialised muscle fibers responsible for the coordinated hook movements. The ultrastructural characteristics of H. hepaticus oncosphere are discussed in comparison with those of previously studied dilepidids and other cyclophyllideans.

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Late stages of egg morphogenesis and ultrastructure of infective eggs in the cestode Staphylocystoides stefanskii [Cyclophyllidea, Hymenolepididae]

80%

Tkach V. V., Swiderski Z.

Wiadomości Parazytologiczne

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1998

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tom 44

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nr 3

3

Ultrastructure of the infective eggs of the hymenolepidid cestode, Ditestolepis tripartita [Zarnowski, 1955], a parasite of shrews

80%

Swiderski Z., Tkach V.

Acta Parasitologica

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1997

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tom 42

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nr 1

The ultrastructure of infective eggs of the hymenolepidid cestode, Ditestolepis tripartita, a parasite of shrews, was examined with emphasis on cellular organisation of mature oncospheres. Each hexacanth larva is surrounded by three main egg envelopes: thin layer of amorphous outer envelope, relatively thick layer of inner envelope with an embryophore and a delicate oncospheral membrane. The outer and inner envelopes of infective eggs of D. tripartita are usually amorphous; the embryophore is relatively thin and moderately electron-dense. Five major types of oncospheral cells have been distinguished. These consist of: (1) about ten germinative cells; (2) about 30 somatic cells (= myocytons of somatic and hook muscles); (3) a bi-nucleate medullary centre (= tegumental perikaryon); (4) a bi-nucleate, U-shaped penetration gland and (5) two cells of neurosecretory type with characteristic dense-cored vesicles. The hook-muscle system with complex interconnections between different muscle fibers provides a structural basis for coordinated hook action.

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Ultrastructure of embryonic development of Inermicapsifer madagascariensis [Cestoda, Anoplocephalidae] with emphasis on the cellular organisation of the infective eggs

80%

Swiderski Z., Tkach V. V.

Acta Parasitologica

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2002

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tom 47

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nr 2

The cellular organisation of the infective eggs of I. madagascariensis has been reconstructed at light (LM) and electron microscopy (EM) level from serial semithin (LM) and ultrathin sections (EM). The oncospheres are surrounded by parenchymatic capsules. The total number of oncospheral cells' is about 44 (50 nuclei). Among them, five major cell types have been distinguished. These consisted of: (1) a six-nucleate, U-shaped penetration gland; (2) a bi-nucleate medullary centre (= sunken perikaryon of oncospheral tegument); (3) two nerve cells of neurosecretory type; (4) about 30 somatic cells (= myocytons of hook and somatic musculature); and (5) about 12 germinative cells (two groups of 6 cells), localised in the posterior pole of the hexacanth. The functional ultrastructure of hook-muscle system and penetration gland and their role in host tissue penetration are discussed.

Ograniczanie wyników

3 Acta Parasitologica

1 Wiadomości Parazytologiczne

4 Swiderski Z.

3 Tkach V. V.

1 Tkach V.

1 Vaucher C.

1 2002

1 2000

1 1998

1 1997

Fine structure of the infective eggs of the dilepidid cestode Hepatocestus hepaticus [Baer, 1932], a parasite of shrews

Late stages of egg morphogenesis and ultrastructure of infective eggs in the cestode Staphylocystoides stefanskii [Cyclophyllidea, Hymenolepididae]

Ultrastructure of the infective eggs of the hymenolepidid cestode, Ditestolepis tripartita [Zarnowski, 1955], a parasite of shrews

Ultrastructure of embryonic development of Inermicapsifer madagascariensis [Cestoda, Anoplocephalidae] with emphasis on the cellular organisation of the infective eggs