Acta Parasitologica, Vol. 51, No. 3, 2006, 194-199 Zdzislaw Swiderski(1,2)*, Jordi Miquel(3), Daniel Mlocicki(1), Lassad Neifar(4), Barbara Grytner-Ziecina(2)
and John S. Mackiewicz(5) - Ultrastructure of vitellocytes in the cestode Progrillotia pastinacae Dollfus, 1946 (Trypanorhyncha, Progrillotiidae)
(1)W. Stefanski Institute of Parasitology, Polish Academy of Sciences, Warsaw, Poland; (2)Department of General Biology and Parasitology,
Warsaw Medical University, Warsaw, Poland; (3)Laboratori de Parasitologia, Departament de Microbiologia i Parasitologia Sanitaries,
Facultat de Farmacia, Universitat de Barcelona, Av. Joan XXIII, sn, 08028 Barcelona, Spain; (4)Laboratoire de Bioecologie Animale,
Departement des Sciences de la Vie, Faculte des Sciences de Sfax, 3018 Sfax, Tunisia; (5)Department of Biological Sciences,
State University of New York at Albany, Albany, N.Y. 12222, U.S.A.
*Corresponding author: z.swider@twarda.pan.pl
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 um in length and about 20 um in width. They have small, elongated, slightly lobulated
nuclei, about 4-5 um 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.
KEY WORDS: Trypanorhyncha, Progrillotiidae, Progrillotia pastinacae, vitellocytes, ultrastructure, TEM