Ultrastructure of spermatozoa of the lung fluke, Paragonimus ohirai (Trematoda: Troglotrematidae), in the seminal receptacle

Abstract

The seminal receptacle of Paragonimus ohirai contains not only mature spermatozoa, but also atypical and degenerate ones, suggesting that abnormal spermatozoa are retained in this organ. The spermatozoon is of a parallel biflagellar type with cortical microtubules, consisting of the anterior region, first mitochondrial region, intermediate (amitochondrial) region, second mitochondrial region, posterior nuclear region (PNR) and tail region (TR). The first third of the spermatozoon exhibits typical undulatory movement, while the middle part shows vibratory movement. At the area between head and midsections (H-M area) the peripheral doublets of axonemes are interrupted, and the external ornamentation is distributed widely around this portion. Throughout the immotile PNR and TR, the axonemes lack the dynein arms of their peripheral doublets. H-M, PNR, and TR ultrastructural characteristics are specific in P. ohirai spermatozoon and seem to be closely related to its pattern of movement.

Ultrastructure of spermatogenesis and sperm development in Saccocoelioides godoyi Kohn & Froes, 1986 (Digenea, Haploporidae)

“…The presence of two centrioles and striated rootlets, and this fusion are general characteristics of parasitic Platyhelminthes (Justine 1991(Justine a,b, 1995. The migration of the nucleus to the distal region of the differentiating spermatozoon observed in S. godoyi was previously reported in H. medioplexus, by Burton (1972), C. vitta by Robinson & Halton (1982) and B. gracilescens by Erwin and Halton (1983), Maritrema linguilla by Hendow & James (1988) and Paragonimus ohirai by Orido (1988).…”

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

“…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.…”

“…In fact, although a single mitochondrion was generally observed in many species of Digenea (Table 1), the presence of several mitochondria had already been reported for digeneans such as D. dendriticum (Morseth 1969;Cifrian et al 1993), Haematoloechus medioplexus (Burton 1972), Pharyngostomoides procyonis (Grant et al 1976), Cryptocotyle lingua (Rees 1979), Paragonimus ohirai (Fujino et al 1977;Orido 1988), Neochasmus sp. (Jamieson and Daddow 1982), Maritrema linguilla (Hendow and James 1988), F. hepatica (Stitt and Fairweather 1990), P. gymnesicus (Gracenea et al 1997), N. neyrai (Ndiaye et al 2003b), and M. parvus ).…”

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

“…The spermatozoon of C. endopapillatus has ultrastructural characteristics which are similar to those of the majority of the digenean: two axonemes of the type 9 + '1' pattern characteristic of the Trepaxonemata (Ehlers 1984), a nucleus, one or two mitochondria and cortical microtubules (Burton 1972;Jamieson and Daddow 1982;Orido 1988;Stitt and Fairweather 1990;Levron et al 2003Levron et al , 2004aNdiaye et al 2003a, b;Seck et al 2007). In Trepaxonemata, only Schistosomatidae and Didymozoidae have flagella with 9 + 0 axonemes considered as a variant of the classic 9 + '1' pattern.…”

“…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).…”