Ultrastructure of vitellocytes in the cestode Progrillotia pastinacae Dollfus, 1946 (Trypanorhyncha, Progrillotiidae)

Abstract

The present study describes the ultrastructure of mature vitellocytes of the trypanorhynch cestode Progrillotia pastinacae Dollfus, 1946 (Progrillotiidae), a parasite of the common stingray Dasyatis pastinaca (Linnaeus, 1758) (Dasyatidae). The vitelline cells of this species measure about 24 μm in length and about 20 μm in width. They have small, elongated, slightly lobulated nuclei, about 4–5 μm in length, with large dense elongated nucleoli and numerous irregularly-shaped dense clumps of heterochromatin. The extensive cytoplasm is rich in numerous cell organelles and cell inclusions. While the perinuclear cytoplasm contains numerous long parallel cisternae of GER, ribo-and polyribosomes, several Golgi complexes and mitochondria, the peripheral cytoplasm contains predominantly three types of cell inclusions: a great number of large lipid droplets, several shell globule clusters, and a very small amount of glycogen-like particles. The most characteristic features of vitellocytes in P. pastinacae are having almost no traces of glycogen and the great number of large, highly osmiophobic lipid droplets representing saturated fatty acids. The presence of large amounts of lipids also in two other trypanorhynchs, Grillotia erinaceus (Beneden, 1858) Guiart, 1927 and Dollfusiella spinulifera (Beveridge et Jones, 2000) Beveridge, Neifar et Euzet, 2004, is in strong contrast to the condition in the most evolved cestodes, Cyclophyllidea, that usually show no trace of lipids.

Ultrastructural and cytochemical studies on vitellogenesis in the trypanorhynch cestode Parachristianella trygonis Dollfus, 1946 (Eutetrarhynchidae)

“…We also compare our data with that from three other trypanorhynch cestodes: Grillotia erinaceus (Lacistorhynchidae), described by McKerr (1985) in his unpublished PhD thesis, D. spinulifera (Eutetrarhynchidae) by OEwiderski et al (2006a) and P. pastinacae (Progrillotiidae) by OEwiderski et al (2006b), in order to assess if the ultrastructural characters of vitellocytes have some value for phylogenetic analysis or if they represent adaptations to different hosts and/or different life cycles. Dollfus, 1946 were obtained from the spiral valve of the common stingray, Dasyatis pastinaca (Linnaeus, 1758), collected in Sidi Mansour and Zarzis (Southern coast of Tunisia, Mediterranean Sea).…”

“…Except for two recent studies on the ultrastructure of vitellogenesis and vitellocytes in Trypanorhyncha, one TEM and cytochemical study on Dollfusiella spinulifera (Eutetrarhynchidae) by OEwiderski et al (2006a) and another TEM study on the vitellocytes of Progrillotia pastinacae (Progrillotidae) by OEwiderski et al (2006b), there are no other published data on this subject. As observed by Palm (2004), TEM studies have been much neglected among the trypanorhynch cestodes.…”

“…Similar staining revealed β-glycogen particles scattered in the cytoplasm of maturing vitellocytes. Typical cytoplasmic β-glycogen particles appeared only seldom during early vitellocyte maturation and were seldom visible in mature vitelline cells of D. spinulifera (OEwiderski et al 2006a) and P. pastinacae (see OEwiderski et al 2006b). …”

Ultrastructure of vitellogenesis and vitellocytes in the trypanorhynch cestode Aporhynchus menezesi, a parasite of the velvet belly lanternshark Etmopterus spinax

“…gyrocotylideans [18], amphilinideans [19], spathebothriideans [20][21][22], caryophyllideans [23][24][25][26][27], diphyllideans [28], four other species of trypanorhynchs [8][9][10][11], rhinebothriideans [29] and bothriocephalideans [30][31][32].…”

“…Grillotia erinaceus (Lacistorhynchidae), Dollfusiella spinulifera, Parachristianella trygonis (Eutetrarhynchidae) and Progrillotia pastinacae (Progrillotiidae) [8][9][10][11].…”