Ultrastructure of spermatogenesis and sperm development in Saccocoelioides godoyi Kohn & Froes, 1986 (Digenea, Haploporidae) (original) (raw)
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Parasite, 2014
This study provides the first ultrastructural data of spermatozoa in the genus Lecithochirium. The spermatozoa of L. microstomum (from Trichiurus lepturus in Senegal) and L. musculus (from Anguilla anguilla in Corsica) exhibit the general pattern described in the great majority of the Digenea, namely two axonemes with the 9 + ''1'' pattern typical of the Trepaxonemata, one mitochondrion, a nucleus, parallel cortical microtubules and external ornamentation of the plasma membrane. Spermatozoa of L. microstomum and L. musculus have some specific features such as the presence of a reduced number of cortical microtubules arranged on only one side of the spermatozoon, the lack of spine-like bodies and expansion of the plasma membrane. The external ornamentation of the plasma membrane entirely covers the anterior extremity of the spermatozoa. The ultrastructure of the posterior extremity of the spermatozoa corresponds to the pattern previously described in the Hemiuridae, characterized by only singlets of the second axoneme. A particularity of these spermatozoa is the organization of the microtubule doublets of the second axoneme around the nucleus in the posterior part of the spermatozoon.
Parasitology Research, 2007
In this paper, we describe the ultrastructural organisation of the spermatozoon of a Digenea Baccigerinae Pronoprymna ventricosa. This spermatozoon possesses the elements found in the others digeneans: two axonemes with 9+"1" pattern, a mitochondrion, a nucleus, cortical microtubules and external ornamentations. However, this spermatozoon presents two particularities. The first is the presence of a single field of cortical microtubules disposed in the ventral side (mitochondrion side) of the spermatozoon. In the other digeneans, two fields of cortical microtubules are observed between the two axonemes. The second is the presence of external ornamentations not associated with cortical microtubules. These two points have, to our knowledge, never been described in another digenean. Moreover, a separation in two groups of the digenean spermatozoa is proposed in relation to the localisation of the external ornamentations. We propose to distinguish a first group exhibiting these elements in the proximal part of the spermatozoon and a second one with external ornamentations in a second part of the gamete.
Tissue and Cell, 2019
The ultrastructure of the spermatozoon of Allopodocotyle tunisiensis (Digenea, Opecoelidae), an intestinal parasite of Solea aegyptiaca (Teleostei, Soleidae), is described by transmission electron microscopy (TEM). The mature spermatozoon is a filiform cell that exhibits two axonemes of different length with the 9+'1' pattern of trepaxonematan Platyhelminthes. In the anterior spermatozoon extremity, cortical microtubules are absent. They appear after the disappearance of an anterior electron-dense material, being initially in a continuous and submembranous layer. They surround only partially the sperm cell. Later, these cortical microtubules are distributed into two bundles. Additionally, the spermatozoon of A. tunisiensis shows two mitochondria, a nucleus, an external ornamentation of the plasma membrane, spine-like bodies, and a large amount of glycogen granules. According to the location of the external ornamentation, A. tunisiensis presents a Quilichini et al.'s type 2 spermatozoon. With respect to the posterior extremity, the sperm cell of A. tunisiensis corresponds to the Quilichini et al.'s opecoelid type. The morphology of the first mitochondrion with a U-shaped posterior extremity is described for the first time in a digenean spermatozoon.
Journal of Parasitology, 2006
Spermiogenesis and ultrastructure of spermatozoon of Nicolla wisniewskii (Digenea, Opecoelidae), an intestinal parasite of Salmo trutta, were studied by electron microscopy. Spermiogenesis follows the general pattern found in the Digenea. It begins with the formation of a differentiation zone, including striated rootlets associated with 2 centrioles and an intercentriolar body. The flagella undergo a rotation of greater than 90Њ. Then, their fusion with the median cytoplasmic process is proximodistal and asynchronous. A peculiarity was observed before the fusion of flagella, i.e., the attachment zones joined as 2 pairs by an electron-dense bridge. The mature spermatozoon is characterized by 2 axonemes, cortical microtubules, a nucleus, 2 mitochondria, external ornamentation, and spinelike bodies. At the posterior end of flagella, the spermatozoon is also characterized by the presence of a central element of the axoneme and without the 9 microtubule doublets. These results were compared with those of the other digeneans and, in particular, with other species of Opecoelidae. It appears that the number of cortical microtubules and their localization in the spermatozoon may be an interesting feature of their phylogeny.
Journal of Parasitology, 2004
spermiogenesis and the ultrastructural organisation of the spermatozoon of the trypanorhynch cestode Aporhynchus menezesi Noever, caira, Kuchta et Desjardins, 2010 are described by means of transmission electron microscopy. type i spermiogenesis of A. menezesi starts with the formation of a differentiation zone containing two centrioles separated by an intercentriolar body constituted by five electron-dense plates. Each centriole gives rise to a free flagellum, which grows at an angle of 90° in relation to a median cytoplasmic process. The nucleus and cortical microtubules elongate along the spermatid body. Later, both flagella rotate and fuse with the median cytoplasmic process. At the final stage of spermiogenesis, the young spermatozoon is detached from the residual cytoplasm by a narrowing of the ring of arched membranes. The mature spermatozoon is a long and filiform cell, tapered at both ends, lacking mitochondria. it is characterized by the presence of two axonemes of the 9+'1' trepaxonematan pattern, the absence of crested bodies, the presence of parallel cortical microtubules and nucleus. this pattern corresponds to the type i spermatozoon of the eucestodes. the anterior extremity of the spermatozoon is characterized by the presence of an arc-like row of up to seven parallel cortical microtubules that partially surrounds the first axoneme. These anterior cortical microtubules are thicker than the posterior microtubules and, consequently, the sperm cell of A. menezesi exhibits two types of cortical microtubules. another interesting aspect is the presence of α-glycogen rosettes. This spermatological pattern is similar to that observed in the spathebothriidean and diphyllobothriidean cestodes.
2004
The ultrastructure of spermiogenesis and the spermatozoon of Poracanthium furcatum (Opecoelidae), parasite of the fish Mullus surmuletus, were studied by electron microscopy. Results were compared with those documented for other digeneans, in particular with Opecoeloides furcatus, another opecoelid. Spermiogenesis follows the general pattern found in the Digenea. Nevertheless, a novel ultrastructural element is described. The posterior part of the centriole is unusual in that it comprises a central element. The mature spermatozoon of P. furcatum presents some characteristics allowing distinction between it and O. furcatus, contrary to the external morphology. It contains a lateral expansion, two mitochondria and a nuclear biflagellar region. Other important ultrastructural features in the spermatozoon include: external ornamentations of the plasma membrane, spine-like bodies, anterior and posterior extremities. All these elements of the male gamete are interesting criteria for phylogenetic studies. Figs 7-12. Successive cross-sections of spermiogenesis of Poracanthium furcatum. 7. Cross-section of the differentiation zone showing the nucleus, the mitochondrion and the start of the striated rootlets. Scale bar = 0.4 µm. 8. Cross-section of the spermatid at the level of the intercentriolar body. Scale bar = 0.4 µm. 9. Cross-section of the differentiation zone at the level of the centriole. Scale bar = 0.4 µm. 10. Crosssection of the spermatid showing the hollow cylinder of the centriole. Scale bar = 0.4 µm. 11. Cross-section of the differentiation zone prior to the proximo-distal fusion. Scale bar = 0.4 µm. 12. Cross-section of the spermatid prior to fusion of the axoneme with the median cytoplasmic process. Note the presence of the fusion line (arrow). Scale bar = 0.4 µm
Acta Zoologica, 2013
The ultrastructural characters of the mature spermatozoon of Opechona bacillaris (Molin, 1859) (Digenea, Lepocreadiidae) a parasite of Scomber colias Gmelin, 1789 (Scombridae) off the coast of Dakar (Senegal).-Acta Zoologica (Stockholm) 96: 91-98. This study presents the ultrastructure of the mature spermatozoon of Opechona bacillaris, a digenean belonging to the family Lepocreadiidae. The sperm cell of O. bacillaris exhibits the general pattern described in most of the Lepocreadioidea: two axonemes of the 9 + '1' pattern of the Trepaxonemata, mitochondria, a cortical mitochondrion, a nucleus, electron-dense material in the anterior extremity of the spermatozoon, external ornamentation of the plasma membrane with associated spinelike bodies, and granules of glycogen. However, particularities of O. bacillaris are the simultaneous presence in the anterior extremity of the spermatozoon of the electron-dense material, a mitochondrion, and the absence of cortical microtubules. In the Lepocreadiidae, we describe for the first time in O. bacillaris spinelike bodies associated with the external ornamentation of the plasma membrane and two mitochondria. The first mitochondrion is moniliform and composed of a mitochondrial cord with joined mitochondrial bulges. The second mitochondrion shows a regular form. The posterior tip of the spermatozoon has only singlets to owing to the disorganization of the second axoneme and granules of glycogen as occurs in Hypocreadium caputvadum, the other studied species of the family Lepocreadiidae.
Acta Parasitologica, 2012
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 ...
Parasitology Research, 2007
To our knowledge, this paper describes the first ultrastructural results on spermiogenesis and the spermatozoon of a Digenea belonging to the family Deropristidae, Deropristis inflata. Spermiogenesis follows the usual pattern found in the digeneans, but a single noteworthy characteristic concerns the centriole, which presents a "prominent pearshaped electron-dense region." Spermiogenesis in D. inflata begins with the formation of a differentiation zone. The two centrioles give rise to flagella. These two flagella undergo a rotation of 90°and fuse with the median cytoplasmic process. The proximo-distal fusion occurs at the level of attachment zones. The mature spermatozoon of D. inflata possesses five regions and presents all the features found in the digenean gamete. However, several characteristics allow us to distinguish the spermatozoon of D. inflata from other digenetic trematoda, namely the external ornamentations of the plasmic membrane, the anterior and posterior extremities. Furthermore, the distal part of the nucleus in front of those of the mitochondria appears such a distinctive criterion in the spermatozoon of this species. Our ultrastructural investigations produce new data on the reproduction of D. inflata, which may be useful for the understanding of the phylogenetic relationships in the Deropristidae family.
Zoologischer Anzeiger, 2016
The mature Podocotyloides magnatestis spermatozoon exhibits two axonemes of the 9 + "1" pattern of the Trepaxonemata, a nucleus, two mitochondria, two bundles of parallel cortical microtubules, spine-like bodies, an external ornamentation of plasma membrane, glycogen granules and an anterolateral electron-dense material. These ultrastructural characteristics have already been described in the Opecoeloidea species studied so far. However, P. magnatestis spermatozoon is distinguished by the fact that its electron-dense material is laterally located on the side of the second axoneme. Moreover, the posterior spermatozoon extremity, characterized by the presence of the nucleus, is observed for the first time in the Opecoelidae.