Ultrastructure of spermiogenesis and spermatozoa ofNotocotylus neyraiGonzález Castro, 1945 (Digenea, Notocotylidae), intestinal parasite ofMicrotus agrestis(Rodentia: Arvicolidae) in Spain

Abstract

To our knowledge, this is the first ultrastructural study on spermiogenesis and the spermatozoon of a trematode belonging to the family Notocotylidae, Notocotylus neyrai. Spermiogenesis begins with the formation of the zone of differentiation which comprises striated rootlets associated with the two centrioles and an intercentriolar body in-between. It is characterised by an asynchronic flagellar rotation and subsequent proximodistal fusion with a median cytoplasmic process. The migration of the nucleus toward the median cytoplasmic process before its fusion with the free flagella is also described. The mature spermatozoon of N. neyrai is filiform and tapered at both ends and presents all the features found in the Digenea gamete: two axonemes, mitochondrion, nucleus and two bundles of parallel cortical microtubules. Nevertheless, several characters allow us to distinguish N. neyrai from other digenetic trematodes.

Dicrocoelium hospes Looss, 1907 (Digenea, Dicrocoeliidae): spermiogenesis, mature spermatozoon and ultrastructural comparative study

“…In D. hospes, at least one of the two free flagella grows externally to the median cytoplasmic process with an angle of about 120°. This fact has also been observed in other digeneans such as F. hepatica (Ndiaye et al 2003a), H. fasciata (Levron et al 2003) and M. parvus . Moreover concerning the latter species, Levron et al (2004) describe an angle of 120°for both free flagella.…”

“…Spermiogenesis Spermiogenesis in D. hospes follows the general pattern described for other digenean species (Mohandas 1983;Orido 1988;Stitt and Fairweather 1990;Gracenea et al 1997;Miquel et al 2000;Baptista-Farias et al 2001;Ndiaye et al 2003a). The presence of two centrioles and striated rootlets and also a proximodistal fusion are general characteristics of parasitic Platyhelminthes Ase anterior spermatozoon extremity, Ax axoneme, Ce cytoplasmic expansion, Cm cortical microtubules, D doublets, Eo extramembranar ornamentation, G granules of glycogen, Mt (number) mitochondria, N nucleus, n several, Pse posterior spermatozoon extremity, Sb spine like bodies.…”

Spermiogenesis and sperm ultrastructure of Carmyerius endopapillatus (Digenea, Gastrothylacidae), a parasite of Bos taurus in Senegal

“…This fusion zone is marked by the presence of four electron dense lines, which appear during the spermiogenesis and persist in the mature spermatozoon. This phenomenon has also been described in many other digenean species: one Haematoloechidae, Haematoloechus medioplexus (Burton 1972), one Didymozoidae, Gonapodasmius (Justine and Mattei 1982a), one Dicrocoeliidae, Corrigia vitta (Robinson and Halton 1982), two Microphallidae, Maritrema linguilla (Hendow and James 1988) and Microphallus primas (Castilho and Barandela 1990), one Haploporidae, Saccocoeliodes godoyi , three Opecoelidae, Opecoeloides furcatus (Miquel et al 2000), Helicometra fasciata (Levron et al 2003), Monorchis parvus (Levron et al 2004a), one Brachylaimidae, Scaphiostomum palaearcticum (Ndiaye et al 2002), one Notocotylidae, Notocotylus neyrai (Ndiaye et al 2003b), two Fasciolidae, Fasciola hepatica (Ndiaye et al 2003a) and Fasciola gigantica (Ndiaye et al 2004), one Paramphistomidae, Paramphistomum microbothrium (Seck et al 2007).…”

“…Such spinelike bodies were described for the first time by Miquel et al (2000) in Opecoeloides furcatus (Opecoelidae). Other recent studies have shown the existence of spinelike bodies in Notocotylus neyrai (Ndiaye et al 2003b), Poracanthium furcatum (Levron et al 2004b), Fasciola gigantica (Ndiaye et al 2004), Dicrocoelium hospes (Agostini et al 2005), Troglotrema acutum (Miquel et al 2006), Crepidostomum metoecus (Quilichini et al 2007a), Nicolla wisniewskii (Quilichini et al 2007b), N. testiobliquum (Quilichini et al 2007c) and Paramphistomum microbothrium (Seck et al 2007). But in these species, except for the last one, the spinelike bodies are not located on the lateral expansion.…”

“…It is the case in Neochasmus sp. , Maritrema linguilla (Hendow and James 1988), Paragonimus ohirai (Orido 1988), Fasciola hepatica (Stitt and Fairweather 1990), Postorchigenes gymnesicus (Gracenea et al 1997), Notocotylus neyrai (Ndiaye et al 2003b), Monorchis parvus (Levron et al 2004a), Poracanthium furcatum (Levron et al 2004b), Dicrocoelium hospes (Agostini et al 2005), Troglotrema acutum (Miquel et al 2006), Deropristis inflata (Foata et al 2007), and Crepidostomum metoecus (Quilichini et al 2007a). The spermatozoon of Sandonia sudanensis contains three mitochondria (Ashour et al 2007).…”