Ultrastructural Study of Spermiogenesis and the Spermatozoon of Crepidostomum Metoecus (Digenea: Allocreadiidae), a Parasite of Salmo Trutta (Pisces: Teleostei)

The ultrastructure of spermiogenesis in Wenyonia virilis Woodland, 1923, a caryophyllaeid cestode from the silurid Nile fish Synodontis schall (Bloch et Schneider, 1801), is described by means of transmission electron microscopy (TEM) for the first time. Spermiogenesis follows the characteristic caryophyllidean type and is initiated by the formation of a differentiation zone. This area, delimited at its base by a ring of arching membranes and bordered by cortical microtubules, contains two centrioles associated with typical striated rootlets with a reduced intercentriolar body between them. The apical area of the differentiation zone exhibits electron-dense material that is present only during the early stages of spermiogenesis. Only one of the centrioles develops into a free flagellum that grows at an angle of >90° in relation to the cytoplasmic extension. Spermiogenesis is also characterized by a flagellar rotation and a proximodistal fusion of the flagellum with the cytoplasmic extension. The most interesting features observed in W. virilis are the presence of a reduced, very narrow intercentriolar body and the unique type of flagellar rotation >90°. Results are compared with those described in two caryophyllideans, Glaridacris catostomi Cooper, 1920 and Khawia armeniaca (Cholodkovski, 1915). Contrary to the original report of OEwiderski and Mackiewicz (2002), that flagellar rotation has never been observed in spermiogenesis of G. catostomi, re-assessment of their description and illustrations leads us to conclude that flagellar rotation must logically occur in that species. The value of various morphological features of sperm in phylogenetic inference is discussed.

Section: Discussionmentioning

confidence: 91%

Ultrastructure of spermiogenesis in the caryophyllidean cestode Wenyonia virilis Woodland, 1923, with re-assessment of flagellar rotation in Glaridacris catostomi Cooper, 1920

Miquel

Świderski²,

Mackiewicz

et al. 2008

“…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.…”

Section: Discussionmentioning

confidence: 95%

“…This rotation has been already observed in most of the studied digenean species (Table I). However, flagella in six others trematodes: Helicometra fasciata (Levron et al 2003), Fasciola hepatica (Ndiaye et al 2003a), Monorchis parvus (Levron et al 2004a), Dicrocoelium hospes (Agostini et al 2005), Nicolla wisniewskii (Quilichini et al 2007a) and Crepidostomum metoecus (Quilichini et al 2007b) undergo a rotation greater than 90°. The flagella of the first four species have the particularity of a rotation of 120° before fusion with the median cytoplasmic expansion.…”

Section: Discussionmentioning

confidence: 99%

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

Seck

Marchand

Bâ

2008

Self Cite

Ultrastructural study of spermiogenesis and of the spermatozoon of Carmyerius endopapillatus has enabled to describe some characteristics of this digenea. The intercentriolar body situated between the two striated roots and the two centrioles, presents a symmetric organization. Both external bands of this intercentriolar body are made up of a row of granules. During spermiogenesis, a flagellar rotation of 90° is described. The old spermatid does not present external ornamentations. The spermatozoon is characterized, in its anterior region, by the presence of a lateral expansion exhibiting one spinelike body. In C. endopapillatus, external ornamentations are localized only at the level where the lateral expansion appears. The posterior extremity of spermatozoon exhibits a nucleus surrounded by a plasmic membrane lacking microtubules, but presenting a small lateral expansion. This is the first species of Gastrothylacidae family studied by transmission electron microscopy.

“…This is also the case for T. taeniaeformis. Taking into account the recent observations of flagellar rotations of up to 120°in the Fasciolidae, Dicrocoeliidae, Monorchiidae, Opecoelidae and Allocreadiidae digeneans (Ndiaye et al 2003c;Levron et al 2003Levron et al , 2004Agostini et al 2005;Quilichini et al 2007a, b), and described in the caryophyllidean Wenyonia virilis and in the spathebothriidean C. truncatus (Bruňanská et al 2006, Miquel et al 2008), it appears that there may be a gradual reduction of the rotation angle until there is no rotation, a state that is considered the apomorphic condition of this character (Justine 1998(Justine , 2001.…”

Section: Spermiogenesismentioning

confidence: 95%

Ultrastructure of spermatogenesis of Taenia taeniaeformis (Batsch, 1786) (Cestoda, Cyclophyllidea, Taeniidae) and comparison of spermatological characters in the family Taeniidae Ludwig, 1886

Miquel

Świderski²,

Foronda³

et al. 2009

The ultrastructure of spermatogenesis of Taenia taeniaeformis is described for the first time by means of transmission electron microscopy (TEM). Mature testes contain all stages of spermatogenesis; primary spermatogonia are usually situated at the periphery and mature spermatozoa in the centre of testes. The general process is similar to that described in other cestodes. Six incomplete, synchronic cytokineses occur: four mitotic and two meiotic cell divisions. All these divisions occur simultaneously, resulting in a rosette cluster of four tertiary spermatogonia, then eight quaternary spermatogonia, and subsequently sixteen primary spermatocytes. All of these enter into a growth period and their enlarged nuclei move to the periphery of cells of the rosettes. The first meiotic division forms thirty-two secondary spermatocytes and after the second meiotic division, there are sixty-four spermatids. Spermiogenesis in T. taeniaeformis corresponds to the Bâ and Marchand's Type 3 and begins with the formation of a differentiation zone in the form of a conical projection of cytoplasm delimited by a ring of arching membranes and surrounded by submembranous cortical microtubules. Within this area, there are two centrioles, orthogonally disposed, and vestigial striated rootlets. Only one of the centrioles develops a flagellum that grows externally to the cytoplasmic extension. Posteriorly, a flagellar rotation inferior to 90º occurs and the flagellum becomes parallel to the cytoplasmic extension. Later, the two processes fuse during the so-called proximodistal fusion. The nucleus elongates and moves into the cytoplasmic extension. In the final stage of spermiogenesis, a single crested body appears at the base of the differentiating spermatozoon. Finally, the ring of arching membranes constricts and the young spermatozoon detaches from the residual cytoplasm. Ultrastructural aspects of spermatogenesis are compared with that of other cestodes studied to date, particularly of the family Taeniidae.