Ultrastructural Study of Vitellogenesis of Aphallus tubarium (Rudolphi, 1819) Poche, 1926 (Digenea: Cryptogonimidae), An Intestinal Parasite of Dentex dentex (Pisces: Teleostei)

Abstract

Vitellogenesis of Aphallus tubarium, an intestinal parasite of Sparidae (Dentex dentex ), was studied by transmission electron microscopy. The ultrastructural features allowed us to distinguish 4 stages in the vitellogenesis process. In stage 1, vitellocytes have a cytoplasm mainly filled with ribosomes, but few mitochondria. In stage 2, there is an increase in amount of endoplasmic reticulum and few Golgi complexes. There is production of shell globules that coalesce into clusters in stage 3; some glycogen particles are observed via the Thiéry method. Finally, in stage 4, mature vitellocytes are filled with shell globule clusters and generally contain a large lipid droplet. Glycogen particles are grouped at the periphery of the cell.

Ultrastructural study of vitellogenesis and oogenesis ofCrepidostomum metoecus(Digenea, Allocreadiidae), intestinal parasite ofSalmo trutta(Pisces, Teleostei)

“…Some vitelline follicles of Digenea possess interstitial cells (or nurse cells) with cytoplasmic extensions between vitellocytes that are believed to be involved in the selection and transport of materials from the parenchyma to the developing vitelline cells [1, 13, 14, 28]. In Crepidostomum metoecus , as in Plagiorchis elegans , or Maritrema feliui , nurse cells were not found [15, 46].…”

“…In Crepidostomum metoecus , as in Plagiorchis elegans , or Maritrema feliui , nurse cells were not found [15, 46]. Vitelline cells provide nutrition for the eggs, and also provide the eggshell substance, in addition to the Mehlis’ gland [13, 28]. The abundance of endoplasmic reticulum, Golgi complexes, and free ribosomes, produces this high synthetic activity [24].…”

Ultrastructural characteristics of the vitellarium of Brandesia turgida (Brandes, 1888) (Digenea: Pleurogenidae) and an examination of the potential usefulness of such vitelline traits in digenean systematics

“…It belongs to the family Pleurogenidae Looss, 1899, a group which is included in the large superfamily Microphalloidea Ward, 1901 along with 17 other families (Bray et al, 2008). Ultrastructural investigations of vitellogenesis in the Digenea have previously been undertaken by Tulloch and Shapiro (1957), Björkman and Thorsell (1963), Burton (1963), Koulish (1969), Irwin and Thread-.... gold (1970), Hanna (1976), Grant et al (1977), Irwin and Maguire (1979), Erasmus et al (1982), Fukuda et al (1983), Holy and Wittrock (1986), Hendow and James (1989), Podvyaznaya (1990Podvyaznaya ( , 2003, Sharma and Swarnakar (1992), Chaymardanov and Tanyüksel (1995), Sampour (2008), Świderski et al (2011Świderski et al ( ), Poddubnaya et al (2012 and Greani et al (2012a, b). Although little attention has been paid to the study of the ultrastructural architecture of the digenean vitellarium itself, three aspects of vitelline cytoarchitecture have been suggested as possibly useful phylogenetic indicators for digeneans (Poddubnaya et al, 2012) and for parasitic platyhelminths in general (Poddubnaya et al, 2013).…”

Ultrastructural and cytochemical aspects of the germarium and the vitellarium in Syndesmis patagonica (Platyhelminthes, Rhabdocoela, Umagillidae)

“…No lipid droplets have been detected in the developing and mature vitellocytes of S. patagonica. As reported by Greani et al (2012b), the production of lipids varies among Platyhelminthes and this variability is particularly evident in the parasitic digeneans where several lipids per vitelline cell have been found in Schistosoma mansoni, only one lipid per cell in Aphallus tubarium and vitellocytes devoid of lipids have been described in Fasciola hepatica. The mature vitellocytes of S. patagonica also contain glycogen deposits whose synthesis increases during the last phase of the vitellocyte maturation process.…”