Spermiogenesis and ultrastructure of the spermatozoon of Wardula capitellata (Digenea, Mesometridae), an intestinal parasite of the sparid teleost Sarpa salpa in Senegal

Abstract

The spermiogenesis process in Wardula capitellata begins with the formation of a differentiation zone containing two centrioles associated with striated rootlets and an intercentriolar body. Each centriole develops into a free flagellum orthogonal to a median cytoplasmic process. Later these flagella rotate and become parallel to the median cytoplasmic process, which already exhibits two electron-dense areas and spinelike bodies before its proximodistal fusion with the flagella. The final stage of the spermiogenesis is characterized by the constriction of the ring of arched membranes, giving rise to the young spermatozoon, which detaches from the residual cytoplasm. The mature spermatozoon of W. capitellata presents most of the classical characters reported in digenean spermatozoa such as two axonemes of different lengths of the 9 + "1" trepaxonematan pattern, nucleus, mitochondrion, two bundles of parallel cortical microtubules and granules of glycogen. However, some peculiarities such as two lateral expansions accompanied by external ornamentation of the plasma membrane and spinelike bodies characterize the mature sperm. Moreover, a new spermatological character is described for the first time, the so-called cytoplasmic ornamented buttons.

Ultrastructure of the spermatozoon of Helicometroides atlanticus (Digenea, Monorchiidae), an intestinal parasite of Parapristipoma octolineatum (Pisces, Teleostei) in Senegal

“…The mature H. atlanticus spermatozoon exhibits two axonemes of the 9 + "1" Trepaxonematan pattern, a nucleus, two mitochondria, cortical microtubules, four attachment zones and extramembranous ornamentations as in numerous digenean species (Justine and Mattei, 1982;Ndiaye et al, 2003aNdiaye et al, ,b, 2004Miquel et al, 2006;Foata et al, 2007;Quilichini et al, 2007a,b,c,d;Kacem et al, 2010;Bakhoum et al, 2012a;Ndiaye et al, 2013). The mature H. atlanticus spermatozoon has some similarities compared to that of M. parvus, the only species which mature spermatozoon has been described until now in the Monorchioidea (Levron et al, 2004).…”

“…Spine-like bodies associated with extramembranous ornamentations have been described in the spermatozoon of the Digenea (Agostini et al, 2005;Quilichini et al, 2007aQuilichini et al, , 2010aBakhoum et al, 2012a;Foata et al, 2012;Ndiaye et al, 2012b). Likewise a cytoplasmic expansion has been reported in many species of Digenea (2004;Agostini et al, 2005;Miquel et al, 2006;Seck et al, 2007).…”

“…In the Digenea, some ultrastructural characters of the mitochondria, the axonemes, the nucleus, the arrangement of cortical microtubules, the presence or not of spine-like bodies, the extramembranous ornamentations and the cytoplasmic expansions have been purposed as tools for the reconstitution of the phylogeny and the systematic (Justine and Mattei, 1982;Miquel et al, 2000;Ndiaye et al, 2003a;Ashour et al, 2007;Kacem et al, 2010;Quilichini et al, 2010aQuilichini et al, ,b, 2011aBakhoum et al, 2012a).…”

Ultrastructural characters of the spermatozoon of the digenean Hypocreadium caputvadum Kacem et al., 2011 (Lepocreadioidea: Lepocreadiidae), an intestinal parasite of Balistes capriscus in Tunisia

“…Considering digeneans, the increase of this kind of studies has motivated the analysis of spermiological data, particularly those related to the mature spermatozoon, in order to establish different types of spermatozoa according to their ultrastructural organization. In the future, the establishment of different types of spermatozoa may be useful for a better knowledge of digenean relationships [12][13][14][15][16]. However, few ultrastructural investigations have been carried out on the superfamily Lepocreadioidea Odhner 1905.…”

Spermatological characteristics ofElstia stossichianum(Digenea, Mesometridae) from the intestine of the cow bream (Sarpa salpa) off Dakar, Senegal

“…Apart from the previously described structures, spermiogenesis in E. stossichianum and also in W. capitellata (Bakhoum et al, 2012) is characterized by the presence of cytoplasmic ornamented buttons described for the first time in these species. Indeed, the formation of these buttons is observed when both flagella have already fused with the median cytoplasmic process in the advanced stages of spermiogenesis.…”