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SEM evidence for existence of an apical disc on the scolex of Clestobothrium crassiceps (Rudolphi, 1819): comparative results of various fixation techniques

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Miquel J., Swiderski Z., Marigo A. M., Delgado E., Torres J.

Acta Parasitologica

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2012

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tom 57

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nr 3

The scolex of the bothriocephalidean cestode Clestobothrium crassiceps was studied by means of scanning electron microscopy (SEM). The comparative results of various fixation procedures and techniques are presented. The scolex of C. crassiceps is oval to globular and exhibits two deep bothria which appear in the form of two lobes separated by a longitudinal groove. At the apex of the scolex, resembling a beret, an apical disc is present (oval, flattened and with a sinuous edge). Our results are compared with those previously reported in other species of Clestobothrium. This study represents the first report which highlights the presence of an apical disc in the scolex of C. crassiceps. It describes the effects of different procedures applied to our material during preparation and a comparative analysis results obtained using these various methods.

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Ultrastructure and cytochemistry of vitellogenesis and the vitellocytes of the bothriocephalidean cestode Clestobothrium crassiceps (Rudolphi, 1819), a parasite of the teleost fish Merluccius merluccius (L., 1758) (Gadiformes, Merlucciidae)

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Swiderski Z., Gibson D. I., Marigo A. M., Delgado E., Torres J., Miquel J.

Acta Parasitologica

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2011

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tom 56

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nr 4

Vitellogenesis and vitellocytes of the bothriocephalidean cestode Clestobothrium crassiceps (Rudolphi, 1819), a parasite of the teleost fish Merluccius merluccius (L., 1758), were studied by means of transmission electron microscopy (TEM) and cytochemistry. During vitellogenesis, four developmental stages were distinguished at the TEM level: (I) a stem cell stage of the gonial type; (II) an early differentiation stage, predominantly exhibiting lipid and protein synthetic activity; (III) an advanced differentiation or vitellocyte maturation stage, primarily exhibiting active glycogenesis still accompanied by an increase in lipid accumulation; and (IV) a mature vitellocyte stage. Vitellogenesis involves: (1) an increase in cell volume; (2) an extensive development of parallel, frequently concentrically arranged, cisternae of granular endoplasmic reticulum (GER) that produce dense, proteinaceous shell-gobules; (3) the development of Golgi complexes engaged in the packaging of this material; (4) an accelerated accumulation of unsaturated and saturated lipid droplets, along with their continuous enlargement and fusion; (5) the formation of individual β-glycogen particles and α-glycogen rosettes and their accumulation in the form of glycogen islands scattered among lipid droplets in the cytoplasm of maturing and mature vitellocytes; and (6) the rapid accumulation of large, saturated lipid droplets accompanied by dense accumulations of α- and β-glycogen along with proteinaceous shell-globules or shell-globule clusters in the peripheral layer during the advanced stage of vitellocyte maturation. Vitellogenesis in C. crassiceps generally resembles that previously described for three other bothriocephalideans, but differs from that of other cestode orders. Cytochemical staining with periodic acid-thiocarbazide-silver proteinate for glycogen indicates a strongly positive reaction for β-glycogen particles and α-glycogen rosettes, which form several large glycogen accumulations around the large, saturated lipid droplets of maturing and mature vitellocytes. Some hypotheses concerning the interrelationships between patterns of vitellogenesis, the possible modes of egg formation, embryonic development and life cycles in cestodes, and their phylogenetic implications are commented upon.

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Frontal glands in the pseudoscolex of Paraechinophallus japonicus [Yamaguti, 1934] [Cestoda, Bothriocephalidea, Echinophallidae]

80%

Poddubnaya L. G., Scholz T., Levron C., Kuchta R., Gibson D. I.

Acta Parasitologica

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2007

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tom 52

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nr 4

The glands in the pseudoscolex of the echinophallid cestode Paraechinophallus japonicus (Bothriocephalidea), a parasite of the bathypelagic fish Psenopsis anomala (Perciformes, Centrolophidae), were studied using scanning and transmission electron microscopy. Two types of glands, with different morphological types of secretory granules and mechanisms for discharging their glandular secretion, were observed. Both types of gland cell bodies are localized in the parenchyma of the pseudoscolex. The syncytial glands of type I are characterized by the production of small (all ∼0.25 μm in diameter), rounded, dense secretory granules which pass though thin projections into the distal tegumental layer of the pseudoscolex. This type of gland has a unique method of discharging its secretory granules, which we call tumulogenesis. The elimination of the secretory products is realized by an encroachment of the basement membrane and underlying tegumental muscles into the surface region of the distal cytoplasm of the tegument, resulting in the formation of a ‘glandular stalk’ above which develops a superficial glandular tumulus. In the region of the glandular material of the tumulus, the basement membrane of the stalk forms a dilation, and the appearance of a membrane-bound area serves to separate the tumulus from the distal cytoplasm of the tegument. Unicellular glands of type II are characterized by large granules (0.4–0.9 μm in diameter), the presence of peripheral microtubules in the terminal region of their ducts and an eccrine mechanism for the discharge of their secretory granules. A comparative analysis of the distribution and morphology of the types of scolex glands among members of the different families of the ‘Pseudophyllidea’ (currently believed to represent two distinct orders, Bothriocephalidea and Diphyllobothriidea) is presented.

Ograniczanie wyników

3 Acta Parasitologica

2 Delgado E.

2 Gibson D. I.

2 Marigo A. M.

2 Miquel J.

2 Swiderski Z.

2 Torres J.

1 Kuchta R.

1 Levron C.

1 Poddubnaya L. G.

1 Scholz T.

1 2012

1 2011

1 2007

SEM evidence for existence of an apical disc on the scolex of Clestobothrium crassiceps (Rudolphi, 1819): comparative results of various fixation techniques

Ultrastructure and cytochemistry of vitellogenesis and the vitellocytes of the bothriocephalidean cestode Clestobothrium crassiceps (Rudolphi, 1819), a parasite of the teleost fish Merluccius merluccius (L., 1758) (Gadiformes, Merlucciidae)

Frontal glands in the pseudoscolex of Paraechinophallus japonicus [Yamaguti, 1934] [Cestoda, Bothriocephalidea, Echinophallidae]