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Spermatological characters in the Dipylidiidae Stiles, 1896 [Cestoda, Cyclophyllidea]

100%

Miquel J., Swiderski Z., Marchand B.

Acta Parasitologica

2005

tom 50

nr 1

The present paper compares the ultrastructural data on spermatology of three dipylidiid species (Dipylidium caninum, Joyeuxiella echinorhynchoides and J. pasqualei) and establishes a general pattern of spermiogenesis and main ultrastructural characters of the mature spermatozoa for the Dipylidiidae. Spermiogenesis is characterized by an external growth of the flagellum followed by a proximodistal fusion of the latter with the cytoplasmic extension. The centrioles are associated with striated rootlets which are thin in D. caninum and well-developed in Joyeuxiella spp. The most characteristic features of the mature spermatozoa of the three species are the presence of a single crest-like body and a periaxonemal sheath. Nevertheless, the three compared species differ in the thickness of these structures. Differences are also observed in the length of the apical cone.

Differentiation and ultrastructure of the oncospheral envelopes of the cestode Joyeuxiella echinorhyncoides [Sonsino, 1889] [Cyclophyllidea, Dipylidiidae]

100%

Swiderski Z., Miquel J., Agostini S., Conn D. B., Chomicz L., Grytner-Ziecina B.

Acta Parasitologica

2004

tom 49

nr 3

In the preoncospheral stage of development of Joyeuxiella echinorhyncoides three primary embryonic envelopes are formed: (1) the capsule; (2) the outer envelope formed by two macromeres, and (3) the inner envelope originating from fusion of three mesomeres. Both the outer and inner envelopes of J. echinorhyncoides are therefore cellular in origin and syncytial in nature. Mature eggs of J. echinorhyncoides are spherical, measuring 47-60 x 38-48 µm in diameter. Each uterine capsule contains one egg. Within fully formed eggs, the mature oncospheres, 25-27 µm in diameter, are surrounded by five oncospheral or egg envelopes: (1) the outer shell, which originates from the initially delicate membranous capsule that becomes encrusted by the uterine-derived shell material that is deposited on it; (2) the outer envelope, still containing two large macromere nuclei; (3) the inner envelope, with three characteristic nuclei of mesomeres, and which secretes the electron-dense protective embryophore layer at its outer surface; (4) a unique type of “oncospheral membrane” that never becomes delaminated or detached from the rest of the inner envelope as a separate layer; and (5) a surface filament layer, composed of numerous elongated processes separated by cisternae containing material of very high electron density. The so-called “hook region membrane” covers only one pole of the mature oncosphere and is directly attached to the oncosphere surface. The ultrastructure of the oncospheral envelopes in J. echinorhyncoides shows some similarity to that described in the only other species of dipylidiid cestode examined to date, the cosmopolitan type-species, Dipylidium caninum. Differences between these two species include the absence of “hook region membrane”, as well as bilayered and striated embryophore unique to D. caninum, and the undetached “oncospheral membrane” and unique “surface filament layer” and “interdigitating cisternae”, characteristic of J. echinorhyncoides eggs.

Ograniczanie wyników

2 Acta Parasitologica

2 Miquel J.

2 Swiderski Z.

1 Agostini S.

1 Chomicz L.

1 Conn D. B.

1 Grytner-Ziecina B.

1 Marchand B.

1 2005

1 2004

Wyniki wyszukiwania

Spermatological characters in the Dipylidiidae Stiles, 1896 [Cestoda, Cyclophyllidea]

Differentiation and ultrastructure of the oncospheral envelopes of the cestode Joyeuxiella echinorhyncoides [Sonsino, 1889] [Cyclophyllidea, Dipylidiidae]