Ultrastructural study on the spermiogenesis and spermatozoon of the metacercariae of Microphallus primas (digenea), a parasite of Carcinus maenas

Abstract

The thread-like spermatozoon of the crab parasite Microphallus primas was studied by electron microscopy. A survey of the head region of the spermatozoon reveals three features hitherto unknown in Platyhelminthes spermatozoa. The first is the aberrant inclusion of the nucleus within one of the two axonemes, limited to the head end region. The second is the coexistence, in the same axoneme, of two patterns, 9 + 0 (doublets without dynein arms) and 9 + "1". The third is the presence of a layer of cortical microtubules running longitudinally from the zone where the nucleus goes from axoneme to the tail region (where the two flagella start). The sequence of events in spermatogenesis is similar to that described for most of the Digenea trematodes, and the spermiogenesis process conforms to a common plan in nearly the whole group.

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).…”

“…In other trematodes, the intercentriolar body is composed of nine electron dense bands. It is the case in: Cryptocotyle lingua (Rees 1979), Microphallus primas (Castilho and Barandela 1990) and Monorchis parvus (Levron et al 2004a). In some trematodes, the intercentriolar body exhibits a symmetrical organization and is composed by six electron dense layers separated by five electron-lucent ones.…”

Ultrastructure of spermiogenesis and the spermatozoon of Monorchis parvus Looss, 1902 (Digenea, Monorchiidae), a parasite of Diplodus annularis (Pisces, Teleostei)

“…The intercentriolar body is formed of nine electrondense layers, like in Cryptocotyle lingua (Rees 1979) and Microphallus primas (Castilho and Barandela 1990). In other studies of Digenea spermiogenesis, the intercentriolar body can be totally absent (Justine and Mattei 1983;Pamplona-Basilio et al 2001), or may contain fewer electron-dense layers (Robinson and Halton 1982;Gracenea et al 1997Gracenea et al , 2000Levron et al 2003).…”

Ultrastructure of spermiogenesis and the spermatozoon of Opecoeloides furcatus (Trematoda, Digenea, Opecoelidae), a parasite of Mullus barbatus (Pisces, Teleostei)

“…(Jamieson and Daddow 1982), Gonapodasmius sp. (Justine and Mattei 1982a), Corrigia vitta (Robinson and Halton 1982), Maritrema linguilla (Hendow and James 1988), Paragonimus ohirai (Orido 1988), Microphallus primas (Castilho and Barandela 1990), Fasciola hepatica (Stitt and Fairweather 1990), Dicrocoelium dendriticum (Cifria n et al 1993), Aporocotyle spinosicanalis and Spirorchis sp. (Justine 1995), Ganeo tigrinum (Sharma and Rai 1995), and Postorchigenes gymnesicus (Gracenea et al 1997).…”