Distribution and ultrastructure of two types of scolex gland cells in adultProteocephalus macrocephalus(Cestoda, Proteocephalidea)

Abstract

Summary :In the scolex-neck region of the adult Proteocephalus macrocephalus two types of eccrine gland cells are present. The first type of gland cells, localized in the frontal part of the scolex only, contains large, more or less round electron lucid granules. The second type of unicellular glands produces large electron dense granules. These electron dense granular gland cells are localized primarily in the neck region, only few are present in the scolex apex. The secretion of both types of gland cells is concentrated in the ducts opening to the exterior. The ducts are fixed to the plasmalemma of the tegument by septate junctions. The function of both types of gland cells is discussed.

Ultrastructure of the surface structures and secretory glands of the rosette attachment organ of Gyrocotyle urna (Cestoda: Gyrocotylidea)

“…An apocrine mechanism for the discharge of secretory gland cells producing electron-dense, spheroidal granules has been observed in the Cyclophyllidea (Kuperman andDavydov 1982, Stoitsova et al 1997). Nevertheless, ultrastructural observations of species of the orders Diphyllobothriidea, Proteocephalidea, Tetraphyllidea and Trypanorhyncha have revealed one or two types of anterior glands possessing only eccrine mechanisms for the release of a secretion comprising rounded electron-dense granules (Andersen 1975, Coggins 1980, Kuperman and Davydov 1982, McCullough and Fairweather 1989, Žďárská and Nebesářová 1999, Bruňan-ská et al 2000, Žďárská et al 2004. It should be mentioned that the predominant secretions of the anterior glands in adult cestodes are glycoproteins (Davydov and Mikryakov 1988, Davydov and Poddubnaya 1988, McCullough and Fairweather 1989, Stoitsova et al 1997.…”

Ultrastructure of the apical glandular region of the scolex of Proteocephalus torulosus (Cestoda: Proteocephalidae)

“…The secretory product of the scolex eccrine glands of P. torulosus differs from that of P. macrocephalus studied earlier by Žďárská and Nebesářová (1999a). In P. torulosus, both types contain electron-dense granules, whereas only one type of eccrine gland produces electron-dense granules and the second one electronlucid granules in P. macrocephalus.…”

“…The gland cells localised around the apical sucker (i.e. on the frontal part of the scolex) were studied in detail in P. macrocephalus (Scholz et al 1998, Žďárská andNebesářová 1999a), P. percae (Andersen 1979, Kuperman 1988, P. longicollis (Bruňanská et al 2000), P. exiguus (Kuperman 1988) (= P. longicollis according to Scholz and Hanzelová 1998) and P. osculatus (Stoitsova et al 1995). The gland cells of the frontal part of the scolex of Proteocephalus species without an apical sucker were studied in P. gobiorum (Kuperman 1988), P. ambloplitis (Coggins 1980), P. sagittus and P. torulosus ).…”

“…The information about the ultrastructure of the tegument, including gland cells, may be useful in the systematics of proteocephalidean and other fish cestodes (Žďárská and Nebesářová, 1997, 1999a, b, 2003, Scholz 1999, Škeříková et al 2001. Scolex gland cells are characteristic of cestodes and occur in all stages of the life cycle (McCullough and Fairweather 1989).…”

Ultrastructure of the scolex of Orygmatobothrium schmittii (Cestoda: Phyllobothriidea)

“…Also, the association between glandular tissues and musculature has been documented in species of Trypanorhyncha, Proteocephalidea, Bothriocephalidea, and Cyclophyllidea (Beveridge & Smith, ; Davydov & Biserova, ; Poddubnaya et al, ; Pospekhova, ; Zd'árská & Nebesářová, ) and likely results in a more efficient secretion.…”