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All issues Volume 21 (2014) Parasite, 21 (2014) 49 Full HTML
Open Access
Issue
Parasite
Volume 21, 2014
Article Number 49
Number of page(s) 12
DOI https://doi.org/10.1051/parasite/2014050
Published online 30 September 2014

© P.I. Ndiaye et al., published by EDP Sciences, 2014

Licence Creative CommonsThis is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Introduction

Like the majority of hemiuroid digeneans, members of the genus Lecithochirium Lühe, 1901 are parasites of the digestive tract of fishes. They belong to the Lecithochiriinae Lühe, 1901, one of the 12 subfamilies of Hemiuridae proposed by Gibson [17]. The systematic position of Lecithochiriinae is problematic. Skrjabin and Guschanskaja [54–59] proposed to remove the Lecithochiriinae from the Hemiuridae. Since, there have been several controversies between authors [5, 10, 16, 18, 19, 32, 61]. However, the Lecithochiriinae are still placed in the Hemiuridae [13, 17].

Ultrastructural data of spermatozoa may provide a useful contribution to understanding of the phylogenetic relationships within the Hemiuridae. In the Platyhelminthes, most ultrastructural features of the spermatozoon proved to be valuable characters for phylogenetic purposes [3, 4, 23–27, 35]. The ultrastructural data, associated with the results of molecular phylogenetic studies, have greatly improved our understanding of the interrelationships in most groups of Platyhelminthes [9, 12, 14, 21, 31, 36–38, 46, 59]. In the Digenea, ultrastructural data of the spermatozoon are available for more than 75 species distributed among 45 families [6, 53]. In the Hemiuroidea, ultrastructural data on spermiogenesis and/or spermatozoa exist for seven species belonging to four families [41]. In the Hemiuridae, such data exist for representatives of only two of the twelve currently recognized subfamilies, namely an elytrophalline, Lecithocladium excisum [42], and a hemiurine, Parahemiurus merus [41]. The present study is the first work of this kind in the Lecithochiriinae and describes the ultrastructural characteristics of the spermatozoon in two representatives of the genus Lecithochirium.

Material and methods

Adult specimens of Lecithochirium microstomum Chandler, 1935 were collected from the digestive tract of Trichiurus lepturus (Linnaeus, 1758) (Pisces, Trichiuridae) caught in the Atlantic Ocean, near Dakar (Senegal). Adult specimens of Lecithochirium musculus (Looss, 1907) were collected from the digestive tract of Anguilla anguilla (Linnaeus, 1758) (Osteichthyes, Anguillidae) caught in Urbino pond, a coastal lagoon of the Mediterranean Sea (Corsica, France).

Live worms were rinsed with a 0.9% NaCl solution and fixed in cold (4 °C) 2.5% glutaraldehyde in a 0.1 M sodium cacodylate buffer at pH 7.2, rinsed in 0.1 M sodium cacodylate buffer at pH 7.2, post-fixed in cold (4 °C) 1% osmium tetroxide in the same buffer for 1 h, rinsed in a 0.1 M sodium cacodylate buffer at pH 7.2, dehydrated in ethanol and propylene oxide, embedded in Spurr’s resin and polymerized at 60 °C for 24 h.

Ultrathin (60–90 nm thick) sections were obtained using an ultramicrotome (Power Tome PC, RMC Boeckeler®) with a diamond knife. Sections placed on copper grids were double-stained with uranyl acetate and lead citrate. Sections were placed on gold grids and stained with periodic acid, thiocarbohydrazide and silver proteinate to reveal the presence of glycogen [60].

The grids were examined in a Hitachi H-7650 transmission electron microscope operated at 80 kV, in the “Service d’Étude et de Recherche en Microscopie Électronique” of the University of Corsica (Corte, France).

Results

Observation of numerous cross- and longitudinal sections of the mature spermatozoa in the seminal vesicle of Lecithochirium microstomum and L. musculus (Figs. 1 and 20) enabled us to establish the ultrastructural organization of their spermatozoa and distinguish in both species four regions (I–IV) from the anterior to the posterior extremities.

thumbnailthumbnailthumbnail Figures 1–19.

1. A fragment of the seminal vesicle of Lecithochirium microstomum containing spermatozoa. Scale bar = 2 μm. Spz = spermatozoon, V = seminal vesicle, Vw = seminal vesicle wall.

2–6. Region I of the spermatozoon of Lecithochirium microstomum. Scale bars = 0.2 μm. (2). A longitudinal section of the anterior extremity of the spermatozoon showing the external ornamentation of the plasma membrane. (3). Cross-section in the anterior extremity of the spermatozoon showing the anterior axonemal extremity 1, the external ornamentation of the plasma membrane and some microtubules. (4). Cross-section showing the external ornamentation of the plasma membrane, the anterior axonemal extremity 1 and some singlets of the axoneme 2. (5). Cross-section showing the axoneme 1, the anterior axonemal extremity 2 and the external ornamentation of the plasma membrane. (6). Cross-section with the two axonemes and the external ornamentation of the plasma membrane. Aae1 = anterior extremity of the first axoneme, Aae2 = anterior extremity of the second axoneme, Ase = anterior spermatozoon extremity, Ax1 = first axoneme, Ax2 = second axoneme, B = bulge, Cm = cortical microtubules, Eo = external ornamentation of the plasma membrane, FEo = filamentous ornamentation, S = singlet.

7–12. Cross-sections of Region II of the spermatozoon of Lecithochirium microstomum. Scale bars = 0.2 μm. (7–9). Two axonemes and cortical microtubules. (10). Two axonemes, cortical microtubules and the nucleus. (11). Two axonemes, cortical microtubules, the nucleus and the mitochondrion. (12). One axoneme completely formed, nucleus, mitochondrion, cortical microtubules and the disorganization of the first axoneme. Ax2 = second axoneme, Cm = cortical microtubules, Mt = mitochondrion, N = nucleus, Pae1 = posterior extremity of the first axoneme.

13–14. Cross-section of Region III of the spermatozoon of Lecithochirium microstomum. Scale bar = 0.2 μm. (13). One axoneme, nucleus, mitochondrion and cortical microtubules. (14). One axoneme, nucleus and cortical microtubules. Ax2 = second axoneme, Cm = cortical microtubules, Mt = mitochondrion, N = nucleus.

15–18. Cross-sections of Region IV of the spermatozoon of Lecithochirium microstomum. Scale bars = 0.2 μm. (15). The second axoneme and nucleus. (16). Disorganization of the second axoneme and nucleus. (17). The nucleus surrounded by the doublets of the disorganized axoneme 2. (18). Cross-section in the posterior extremity of the spermatozoon showing only the posterior extremity of the second axoneme. N = nucleus, Pae 2 = posterior extremity of the second axoneme.

19. Transmission electron micrograph of spermatozoa of Lecithochirium microstomum showing glycogen granules (G) revealed by the test of Thiéry. Scale bar = 0.2 μm.
thumbnailthumbnail Figures 20–37.

20. A fragment of the seminal vesicle of Lecithochirium musculus containing spermatozoa. Scale bar = 2 μm. Spz = spermatozoon, V = seminal vesicle, Vw = seminal vesicle wall.

21–24. Region I of the spermatozoon of Lecithochirium musculus. Scale bars = 0.2 μm. (21). A longitudinal section of the anterior extremity of the spermatozoon showing the external ornamentation of the plasma membrane. (22). Cross-section in the anterior extremity of the spermatozoon showing the anterior extremity of the first axoneme and the external ornamentation of the plasma membrane. (23). Cross-section exhibiting the axoneme 1, the external ornamentation of the plasma membrane and singlets of the second axoneme. (24). Cross-section showing the two axonemes and the external ornamentation of the plasma membrane. Aae1 = anterior extremity of the first axoneme, Ase = anterior spermatozoon extremity, Ax1 = first axoneme, Ax2 = second axoneme, B = bulge, Eo = external ornamentation of the plasma membrane, S = singlet.

25–30. Cross-sections of Region II of the spermatozoon of Lecithochirium musculus. Scale bars = 0.2 μm. (25–26). Two axonemes and some cortical microtubules. (27–28). Two axonemes, cortical microtubules and the nucleus. (29). Two axonemes, cortical microtubules, the nucleus and the mitochondrion. (30). One axoneme, nucleus, mitochondrion, cortical microtubules and the posterior axonemal extremity 1. Ax2 = second axoneme, Cm = cortical microtubules, Mt = mitochondrion, N = nucleus, Pae1 = posterior extremity of the first axoneme.

31–32. Cross-section of Region III of the spermatozoon of Lecithochirium musculus. Scale bars = 0.2 μm. (31). The second axoneme, nucleus, mitochondrion and some cortical microtubules. (32). The second axoneme, nucleus and some microtubules. Ax2 = second axoneme, Cm = cortical microtubules, Mt = mitochondrion, N = nucleus.

33–36. Cross-section of Region IV of the spermatozoon of Lecithochirium musculus. Scale bars = 0.2 μm. (33). Cross-section of the spermatozoon showing the second axoneme, nucleus and one cortical microtubule. (34). Cross-section of the spermatozoon showing the second axoneme disorganized and the nucleus. (35). Cross-section of the spermatozoon showing the nucleus surrounded by doublets from the second axoneme. (36). Cross-section showing the posterior extremity of the spermatozoon with only the posterior extremity of the second axoneme. Cm = cortical microtubules, N = nucleus, Pae 2 = posterior extremity of the second axoneme.

37. Transmission electron micrograph of spermatozoa of Lecithochirium musculus showing glycogen granules (G) revealed by the test of Thiéry. Scale bar = 0.2 μm.

Region I (Figs. 2–6, 21–24 and 38I)

This region corresponds to the anterior extremity of the spermatozoon. It exhibits a bulge (Figs. 2 and 21) associated with an external ornamentation of the plasma membrane. Cross-sections in the bulge show the presence of the anterior extremity of the first axoneme, the ornamentation of the plasma membrane and some cortical microtubules under the plasma membrane associated with filamentous ornamentation (Fig. 3). Soon the first axoneme appears completely formed and the singlets of the second axoneme. The appearance of the singlets of the second axoneme coincides with the disappearance of the cortical microtubules (Figs. 4 and 23). The posterior part of this region exhibits only two axonemes and the external ornamentation of the plasma membrane located only around the first axoneme (Figs. 5, 6 and 24).

thumbnail Figure 38.

Schematic reconstruction of the spermatozoon in the genus Lecithochirium: L. musculus (in black), L. microstomum (in black + red). Aae1 = anterior extremity of the first axoneme, Aae2 = anterior extremity of the second axoneme, Ase = anterior spermatozoon extremity, Ax1 = first axoneme, Ax2 = second axoneme, B = bulge, Cm = cortical microtubules, Eo = external ornamentation of the plasma membrane, FEo = filamentous ornamentation, G = granules of glycogen, M = mitochondrion, N = nucleus, Pae1 = posterior extremity of the first axoneme, Pae2 = posterior extremity of the second axoneme, Pm = plasma membrane, Pse = posterior spermatozoon extremity.

Region II (Figs. 7–12, 25–30 and 38II)

This region is characterized by the disappearance of the external ornamentation of the plasma membrane (Figs. 7 and 25), the gradual appearance of cortical microtubules disposed on only one side of the spermatozoon (Figs. 7–9, 25, 26 and 30) and the appearance of the nucleus (Figs. 10–11 and 27) and the mitochondrion (Figs. 11, 12, 29 and 30) in the posterior part of this region. In L. microstomum the number of cortical microtubules increases in this region by one (Fig. 7) to eight (Figs. 9–11). In L. musculus, this number increases by one (Fig. 25) to six in association with the nucleus (Figs. 28–30). Cross-sections in the posterior extremity of this region show the posterior extremity of the first axoneme in both species (Figs. 12 and 30).

Region III (Figs. 13–14, 31–33 and 38III)

This region is characterized by the disappearance of the first axoneme in both L. microstomum and L. musculus. The number of cortical microtubules in L. microstomum decreases from 6 (Fig. 13) to 3 (Fig. 14). In L. musculus, this number decreases to 5 (Figs. 31–32) and to 1 (Fig. 33). This region is also characterized by the disappearance of the mitochondrion (Figs. 13–14 and 31–33).

Region IV (Figs. 15–18, 33–36 and 38IV)

This region corresponds to the posterior region of the spermatozoon. Cortical microtubules disappear and the nucleus size decreases progressively (Figs. 15–17, 34 and 35). Cross-sections in the posterior part of the spermatozoon show the reduced nucleus surrounded by doublets of the disorganized second axoneme (Figs. 17 and 35). The posterior extremity of the spermatozoon is characterized by the disappearance of the nucleus and the presence of only the posterior extremity of the axoneme 2 (Figs. 18 and 36).

The micrographs in Figures 19 and 37 show a positive result of the Thiéry test, exhibiting a reduced presence of glycogen granules along the mature spermatozoa in both species studied.

Discussion

Spermatozoa of L. microstomum and L. musculus exhibit the general pattern described in most of the Digenea, namely two axonemes of the 9 + “1” pattern of trepaxonematans [15], a nucleus, one mitochondrion and parallel cortical microtubules, and are tapered at both ends [8, 11, 22, 23, 33, 39, 41, 52, 53]. However, spermatozoa of Lecithochirium are also characterized by several specific features.

The anterior spermatozoon extremity

The spermatozoon extremity of the two species is filiform and exhibits a bulge described here for the first time in the Digenea. It is also covered by an external ornamentation of the plasma membrane. In the other two Hemiuridae studied so far, namely Lecithocladium excisum and Parahemiurus merus [41, 42], the anterior extremity of the spermatozoon has only one axoneme and external ornamentation of the plasma membrane. The unique feature of the spermatozoa of Lecithochirium is the presence of a few short cortical microtubules (6) in the anterior extremity of the spermatozoon in addition to the filamentous external ornamentation of the plasma membrane. In the Hemiuroidea, this type of anterior spermatozoon extremity was previously described only in Gonapodasmius sp. by Justine and Mattei [28, 30] (see Table 1) and in Prosorchis palinurichthi [45]. In 2011, Quilichini et al. [48] distinguished three types of digenean spermatozoa according to the localization of the external ornamentation: type 1 (external ornamentation in the anterior extremity of the spermatozoon), type 2 (external ornamentation at a more posterior level) and type 3 (absence of external ornamentation). According to this criterion, the hemiuroidean spermatozoa can be classified as the first type (Table 1).

Table 1.

Spermatological characters in the superfamily of Hemiuroidea (Ndiaye et al. [41] completed).

In the majority of digeneans studied up to now, the external ornamentation of the plasma membrane is associated with spine-like bodies [7, 39, 41, 43, 51]. However, these structures are absent in the spermatozoon of all studied Hemiuroidea.

Cortical microtubules

Cortical microtubules were described in spermatozoa of almost all of the digeneans studied so far. They are generally disposed in two bundles. One of the specific features of the spermatozoon of the Hemiuridae is the presence of only one reduced bundle of cortical microtubules on one side of the spermatozoon [41, 42 and present study]. Up to now, the maximum number of cortical microtubules encountered in Hemiuridae was eight in Lecithochirium excisum [42] and Lecithochirium microstomum (this study). The spermatozoon of Lecithochirium musculus exhibits only six cortical microtubules (this study). P. merus [41] has the smallest number of cortical microtubules (5) in Hemiuridae. The number of cortical microtubules is higher in other Hemiuroidea: 10 in Aponurus laguncula [49], 13 in Prosorchis ghanensis [25], 25 in Prosorchis palinurichthi [45] and 36 in Gonapodasmius sp. [28, 30].

The principal difference between L. microstomum and L. musculus is in the number of cortical microtubules. In L. microstomum the maximum number of cortical microtubules is observed in the region of the spermatozoon with only the two axonemes, glycogen granules and nucleus. However, in L. musculus, the maximum number of cortical microtubules is six and is situated in a region of the spermatozoon with the simultaneous presence of the nucleus and the mitochondrion.

Mitochondrion

Similar to other taxa of the Hemiuroidea studied up to now (Table 1), the spermatozoa of L. microstomum and L. musculus have only one mitochondrion. Among more than 75 studied species of Digenea, spermatozoa with one mitochondrion were described in 40 species (see [6] completed by [40, 41, 45]). In the remaining species, spermatozoa with two or three mitochondria were described [1, 2, 20, 34, 44, 51].

Posterior spermatozoon extremity

The posterior part of the spermatozoon is identical in both species of Lecithochirium examined in our study and characterized by the presence of only the nucleus and the posterior extremity of the second axoneme. The posterior extremity of the spermatozoa is particular and characterized by a disorganization of the axoneme associated with the migration of the posterior extremity of the nucleus in the central part of the disorganized axoneme. Thus, in the end of this posterior extremity, the nucleus disappears, and instead only the axonemal singlets are present in the posterior end of the spermatozoon. A posterior end of the spermatozoon with only axonemal singlets was described in all the Hemiuridae studied so far [41, 42]. This suggests that this character can be a useful criterion for phylogenetic purposes. The presence of the nucleus in the posterior part of the spermatozoon was also described in all studied hemiurids [41, 42, present study]. In P. merus, some cortical microtubules are described in the posterior extremity of the spermatozoon. However, in L. microstomum and L. musculus (present study), cortical microtubules in the posterior extremity of the spermatozoon are absent. Similar to the other Hemiuridae studied to date [41, 42], the spermatozoon in Lecithochirium presents the type III or Cryptogonimidean type characterized by the absence of cortical microtubules, and the sequence posterior extremity of the nucleus then posterior extremity of the second axoneme [50]. The terminal character is coincident in all Hemiuridae. However, the end of the cortical microtubules is different in Lecithocladium.

Glycogen

The presence of glycogen was described in most of the spermatozoa of digeneans described up to now. However, the particularity of the Hemiuridae is the presence of a reduced quantity of glycogen. We believe that it is necessary to perform more studies of this character to clarify its potential importance for the phylogeny of the Hemiuridae.

References

  1. Agostini S, Miquel J, Ndiaye PI, Marchand B. 2005. Dicrocoelium hospes Looss, 1907 (Digenea, Dicrocoeliidae): spermiogenesis, mature spermatozoon and ultrastructural comparative study. Parasitology Research, 96, 38–48. [CrossRef] [PubMed] [Google Scholar]
  2. Ashour AA, Garo K, Gamil IS. 2007. Spermiogenesis in two paramphistomes from Nile fish in Egypt: an ultrastructural study. Journal of Helminthology, 81, 219–226. [CrossRef] [PubMed] [Google Scholar]
  3. Bâ CT, Marchand B. 1995. Spermiogenesis, spermatozoa and phyletic affinities in the Cestoda, in Advances in spermatozoal phylogeny and taxonomy, Jamieson BGM, Ausió J, Justine J-L, Editors. Mémoires du Muséum National d′Histoire Naturelle: Paris. 166, 87–95. [Google Scholar]
  4. Bâ CT, Marchand B. 1996. Spermatides et spermatozoïdes: outils phylogénétiques exemple de Mathevotaenia herpestis parasite du hérisson à ventre blanc Atelerix albiventris. Vie et Milieu, 46, 382. [Google Scholar]
  5. Baer JG, Joyeux C. 1961. Classe de Trématodes, in Traité de Zoologie, Vol. IV, Grassé P-P, Editor. Masson: Paris. p. 561–692. [Google Scholar]
  6. Bakhoum AJS. 2012. Contribution à la connaissance de l’ultrastructure de la spermiogenèse et du spermatozoïde des digènes. Mémoire de thèse, Facultat de Farmacia, Universidad de Barcelona, 288 pp. http://www.tdx.cat/handle/10803/109050. [Google Scholar]
  7. Bakhoum AJS, Feliu C, Bâ CT, Miquel J. 2012. Spermiogenesis and spermatozoon of the liver fluke Mediogonimus jourdanei (Microphalloidea: Prosthogonimidae), a parasite of Myodes glareolus (Rodentia: Cricetidae). Folia Parasitologica, 59, 32–42. [CrossRef] [PubMed] [Google Scholar]
  8. Bakhoum AJS, Ndiaye PI, Sène A, Bâ CT, Miquel J. 2012. Spermiogenesis and ultrastructure of the spermatozoon of Wardula capitellata (Digenea, Mesometridae), an intestinal parasite of the sparid teleost Sarpa salpa in Senegal. Acta Parasitologica, 57, 34–45. [CrossRef] [Google Scholar]
  9. Brabec J, Kuchta R, Scholz T. 2006. Paraphyly of the Pseudophyllidea (Platyhelminthes: Cestoda): Circumscription of monophyletic clades based on phylogenetic analysis of ribosomal RNA. International Journal for Parasitology, 36, 1535–1541. [CrossRef] [PubMed] [Google Scholar]
  10. Brooks DR, O’Grady RT, Glen DR. 1985. Phylogenetic analysis of the Digenea (Platyhelminthes: Cercomeria) with comments on their adaptive radiation. Canadian Journal of Zoology, 63, 411–443. [CrossRef] [Google Scholar]
  11. Burton PR. 1972. Fine structure of the reproductive system of a frog lung-fluke. III. The spermatozoon and its differentiation. Journal of Parasitology, 58, 68–83. [CrossRef] [Google Scholar]
  12. Caira JN, Jensen K, Healy CJ. 1999. On the phylogenetic relationships among tetraphyllidean, lecanicephalidean and diphyllidean tapeworm genera. Systematic Parasitology, 42, 77–151. [CrossRef] [PubMed] [Google Scholar]
  13. Carreras-Aubets M, Montero FE, Kostadinova A, Gibson DI, Carrassón M. 2012. Redescriptions of two frequently recorded but poorly known hemiurid digeneans, Lecithochirium musculus (Looss, 1907) (Lecithochiriinae) and Ectenurus lepidus Looss, 1907 (Dinurinae), based on material from the western Mediterranean. Systematic Parasitology, 82, 185–199. [CrossRef] [PubMed] [Google Scholar]
  14. Cribb TH, Bray RA, Littlewood DTJ, Pichelin SP, Herniou EA. 2001. The Digenea, in Interrelationships of the Platyhelminthes. Littlewood DTJ, Bray RA, Editors. Taylor and Francis: London. p. 168–185. [Google Scholar]
  15. Ehlers U. 1984. Phylogenetisches System der Plathelminthes. Verhandlungen des Naturwissenschaftlichen Verein in Hamburg (NF), 27, 291–294. [Google Scholar]
  16. Gibson DI. 1996. Trematoda, in Guide to the Parasites of Fishes of Canada Part IV. Margolis L, Kabata Z, Editors. NRC Press: Ottawa. p. 1–373. [Google Scholar]
  17. Gibson DI. 2002. Family Hemiuridae Looss, 1899, in Keys to the Trematoda Vol. 1 Gibson DI, Jones A, Bray RA, Editors. CABI International and The Natural History Museum: London. p. 305–340. [Google Scholar]
  18. Gibson DI, Bray RA. 1979. The Hemiuroidea: terminology, systematic and evolution. Bulletin of the British Museum (Natural History) (Zoology), 36, 35–146. [Google Scholar]
  19. Gibson DI, Bray RA. 1986. The Hemiuridae (Digenea) of fishes from the northeast Atlantic. Bulletin of the British Museum (Natural History) (Zoology), 51, 1–125. [Google Scholar]
  20. Hendow HT, James BL. 1988. Ultrastructure of spermatozoon and spermatogenesis in Maritrema linguilla (Digenea: Microphallidae). International Journal for Parasitology, 18, 53–63. [CrossRef] [PubMed] [Google Scholar]
  21. Hoberg EP, Mariaux J, Justine J-L, Brooks DR, Weekes PJ. 1997. Phylogeny of the orders of the Eucestoda (Cercomeromorphae) based on comparative morphology: historical perspectives and a new working hypothesis. Journal of Parasitology, 83, 1128–1147. [CrossRef] [Google Scholar]
  22. Iomini C, Justine J-L. 1997. Spermiogenesis and spermatozoon of Echinostoma caproni (Platyhelminthes, Digenea): transmission and scanning electron microscopy, and tubulin immunocytochemistry. Tissue & Cell, 29, 107–118. [Google Scholar]
  23. Jamieson BGM, Daddow LM. 1982. The ultrastructure of the spermatozoon of Neochasmus sp. (Cryptogonimidae, Digenea, Trematoda) and its phylogenetic significance. International Journal for Parasitology, 12, 547–559. [CrossRef] [Google Scholar]
  24. Justine J-L. 1991. Spermatozoa as a tool for taxonomy of species and supraspecific taxa in the Platyhelminthes, in Comparative Spermatology 20 Years After. Bacceti B, Editor. Raven Press: New York. p. 981–984. [Google Scholar]
  25. Justine J-L. 1995. Spermatozoal ultrastructure and phylogeny of the parasitic Platyhelminthes. In: Jamieson B.G.M., Ausió J. & Justine J.-L. (Eds.), Advances in spermatozoal phylogeny and taxonomy. Mémoires du Muséum National d’Histoire Naturelle, 166, 55–86. [Google Scholar]
  26. Justine J-L. 1998. Spermatozoa as phylogenetic characters for the Eucestoda. Journal of Parasitology, 84, 385–408. [CrossRef] [Google Scholar]
  27. Justine J-L. 2001. Spermatozoa as phylogenetic characters for the Platyhelminthes, in Interrelationships of the Platyhelminthes. Littlewood DTJ, Bray RA, Editors. Taylor and Francis: London. p. 231–238. [Google Scholar]
  28. Justine J-L, Mattei X. 1982. Étude ultrastructurale de la spermiogenèse et du spermatozoïde d’un Plathelminthe: Gonapodasmius (Trematoda: Didymozoidae). Journal of Ultrastructure Research, 79, 350–365. [CrossRef] [PubMed] [Google Scholar]
  29. Justine J-L, Mattei X. 1983. A spermatozoon with two 9+0 axonemes in a parasitic flatworm, Didymozoon (Digenea : Didymozoidae). Journal of Submicroscopic Cytology and Pathology, 15, 1101–1105. [Google Scholar]
  30. Justine J-L, Mattei X. 1984. Ultrastructural observations on the spermatozoon, ovocyte and fertilization process in Gonapodasmius, a gonochoristic Trematode (Trematoda: Digenea: Didymozoidae). Acta Zoologica (Stockholm), 65, 171–177. [CrossRef] [Google Scholar]
  31. Kodedová I, Doležel D, Broučková M, Jirků M, Hypša V, Lukeš J, Scholz T. 2000. On the phylogenetic positions of the Caryophyllidea, Pseudophyllidea and Proteocephalidea (Eucestoda) inferred from 18S rRNA. International Journal for Parasitology, 30, 1109–1113. [CrossRef] [PubMed] [Google Scholar]
  32. La Rue GR. 1957. The classification of digenetic Trematoda: a review and a new system. Experimental Parasitology, 6, 306–344. [CrossRef] [PubMed] [Google Scholar]
  33. Levron C, Ternengo S, Marchand B. 2004. Ultrastructure of spermiogenesis and the spermatozoon of Monorchis parvus Looss, 1902 (Digenea, Monorchiidae), a parasite of Diplodus annularis (Pisces, Teleostei). Parasitology Research, 93, 102–110. [CrossRef] [PubMed] [Google Scholar]
  34. Levron C, Ternengo S, Marchand B. 2004. Spermiogenesis and sperm ultrastructure of Poracanthium furcatum (Digenea, Opecoelidae), a parasite of Mullus surmuletus (Pisces, Teleostei). Acta Parasitologica, 49, 190–200. [Google Scholar]
  35. Levron C, Miquel J, Oros M, Scholz T. 2010. Spermatozoa of tapeworms (Platyhelminthes, Eucestoda): advances in ultrastructural and phylogenetic studies. Biological Reviews, 85, 523–543. [Google Scholar]
  36. Littlewood DTJ, Bray RA, Clough KA. 1998. A phylogeny of the Platyhelminthes: towards a total-evidence solution. Hydrobiologia, 383, 155–160. [CrossRef] [Google Scholar]
  37. Littlewood DTJ, Olson PD. 2001. Small subunit rDNA and the Platyhelminthes: Signal, noise, conflict and compromise, in Interrelationships of the Platyhelminthes. Littlewood DTJ, Bray RA, Editors. Taylor & Francis: London. p. 262–278. [Google Scholar]
  38. Mariaux J. 1998. A molecular phylogeny of the Eucestoda. Journal of Parasitology, 84, 114–124. [CrossRef] [Google Scholar]
  39. Miquel J, Nourrisson C, Marchand B. 2000. Ultrastructure of spermiogenesis and the spermatozoon of Opecoeloides furcatus (Trematoda, Digenea, Opecoelidae), a parasite of Mullus barbatus (Pisces, Teleostei). Parasitology Research, 86, 301–310. [CrossRef] [PubMed] [Google Scholar]
  40. Miquel J, Vilavella D, Swiderski Z, Shimalov VV, Torres J. 2013. Spermatological characteristics of Pleurogenidae (Digenea) inferred from the ultrastructural study of Pleurogenes claviger. Pleurogenoides medians and Prosotocus confusus. Parasite, 20, 28. [Google Scholar]
  41. Ndiaye PI, Bakhoum AJS, Sène A, Miquel J. 2013. Ultrastructure of the spermatozoon of Parahemiurus merus (Linton, 1910) (Digenea: Hemiuroidea: Hemiuridae), a parasite of Sardinella aurita Valenciennes, 1847 and S. maderensis (Lowe, 1838) (Teleostei: Clupeidae) in the Senegalese coast. Zoologischer Anzeiger, 252, 572–578. [CrossRef] [Google Scholar]
  42. Ndiaye PI, Diagne PM, Sène A, Bakhoum AJS, Miquel J. 2012. Ultrastructure of the spermatozoon of the digenean Lecithocladium excisum (Rudolphi, 1819) (Hemiuroidea, Hemiuridae), a parasite of marine teleost in Senegal. Folia Parasitologica, 59, 173–178. [CrossRef] [PubMed] [Google Scholar]
  43. Ndiaye PI, Miquel J, Bâ CT, Marchand B. 2004. Spermiogenesis and ultrastructure of the spermatozoon of the liver fluke Fasciola gigantica Cobbold, 1856 (Digenea, Fasciolidae), a parasite of cattle in Senegal. Journal of Parasitology, 90, 30–40. [CrossRef] [Google Scholar]
  44. Ndiaye PI, Miquel J, Fons R, Marchand B. 2003. Spermiogenesis and sperm ultrastructure of the liver fluke Fasciola hepatica L., 1758 (Digenea, Fasciolidae): scanning and transmission electron microscopy, and tubulin immunocytochemistry. Acta Parasitologica, 48, 182–194. [Google Scholar]
  45. Ndiaye PI, Quilichini Y, Sène A, Bray RA, Bâ CT, Marchand B. 2013. Prosorchis palinurichthi Kurochkin & Korotaeva, 1971 (Digenea, Sclerodistomidae): ultrastructure of the mature spermatozoon. Zoologischer Anzeiger, 252, 404–409. [CrossRef] [Google Scholar]
  46. Olson PD, Cribb TH, Tkach VV, Bray RA, Littlewood DTJ. 2003. Phylogeny and classification of the Digenea (Platyhelminthes: Trematoda). International Journal for Parasitology, 33, 733–755. [CrossRef] [PubMed] [Google Scholar]
  47. Pamplona-Basilio MC, Baptista-Farias MFD, Kohn A. 2001. Spermatogenesis and spermiogenesis in Didymocystis wedli Ariola, 1902 (Didymozoidae, Digenea). Memórias do Instituto Oswaldo Cruz, 96, 1153–1159. [CrossRef] [Google Scholar]
  48. Quilichini Y, Foata J, Justine J-L, Bray RA, Marchand B. 2011. Spermatozoon ultrastructure of Gyliauchen sp. (Digenea: Gyliauchenidae), an intestinal parasite of Siganus fuscescens (Pisces: Teleostei). Biological Bulletin, 221, 197–205. [Google Scholar]
  49. Quilichini Y, Foata J, Justine J-L, Bray RA, Marchand B. 2010. Spermatozoon ultrastructure of Aponurus laguncula (Digenea: Lecithasteridae), a parasite of Aluterus monoceros (Pisces, Teleostei). Parasitology International, 59, 22–28. [CrossRef] [PubMed] [Google Scholar]
  50. Quilichini Y, Foata J, Justine J-L, Bray RA, Marchand B. 2010. Ultrastructure study of the spermatozoon of Heterolebes maculosus (Digenea, Opistholebetidae), a parasite of the porcupinefish Diodon hystrix (Pisces, Teleostei). Parasitology International, 59, 427–434. [CrossRef] [PubMed] [Google Scholar]
  51. Quilichini Y, Foata J, Marchand B. 2007. Ultrastructural study of the spermatozoon of Nicolla testiobliquum (Digenea, Opecoelidae) parasite of brown trout Salmo trutta (Pisces, Teleostei). Parasitology Research, 101, 1295–1301. [CrossRef] [PubMed] [Google Scholar]
  52. Seck MT, Marchand B, Bâ CT. 2008. Spermiogenesis and sperm ultrastructure of Cotylophoron cotylophorum (Trematoda, Digenea, Paramphistomidae), a parasite of Bos taurus in Senegal. Parasitology Research, 103, 157–166. [CrossRef] [PubMed] [Google Scholar]
  53. Sène A. 2013. Études morpho-anatomiques et ultrastructurales de la spermiogenèse et du spermatozoïde de quelques cestodes et trématodes parasites de poissons et de tortues au Sénégal. Thèse de doctorat d’état es Sciences, Faculté des Sciences et Techniques de l’Université Cheikh Anta Diop de Dakar (Sénégal), 144 pp. [Google Scholar]
  54. Skrjabin KI, Guschanskaja LK. 1954. Suborder Hemiurata (Markevitsch, 1951) Skrjabin et Guschanskaja, 1954. First part. In: Skrjabin, K.I. (ed.) Trematodes of animals and man. Osnovy Trematodologii, 9, 225–653 (In Russian). [Google Scholar]
  55. Skrjabin KI, Guschanskaja LK. 1955. Suborder Hemiurata (Markevitsch, 1951) Skrjabin et Guschanskaja, 1954. Second part. In: Skrjabin, K.I. (ed.) Trematodes of animals and man. Osnovy Trematodologii, 10, 337–643. (In Russian). [Google Scholar]
  56. Skrjabin KI, Guschanskaja LK. 1955. Suborder Hemiurata (Markevitsch, 1951) Skrjabin et Guschanskaja, 1954. Third part. In: Skrjabin, K.I. (ed.) Trematodes of animals and man. Osnovy Trematodologii, 11, 645–748 (In Russian). [Google Scholar]
  57. Skrjabin KI, Guschanskaja LK. 1956. System of trematodes of the suborder Hemiurata (Markevitsch, 1951) Skrjabin et Guschanskaja, 1954. Trudy Gel’mintologicheskoi Laboratorii, 8, 144–158 (In Russian). [Google Scholar]
  58. Skrjabin KI, Guschanskaja LK. 1957. Supplement to suborder Hemiurata (Markevitsch, 1951) Skrjabin et Guschanskaja, 1954. In: Skrjabin, K.I. (ed.) Trematodes of animals and man, Osnovy Trematodologii, 13, 723–779 (In Russian). [Google Scholar]
  59. Thaenkham U, Dekumyoy P, Komalamisra C, Sato M, Dung DT, Waikagul J. 2010. Systematics of the subfamily Haplorchiinae (Trematoda- Heterphyidae), based on nuclear ribosomal DNA genes and ITS 2 region. Parasitology International, 59, 460–465. [CrossRef] [PubMed] [Google Scholar]
  60. Thiéry JP. 1967. Mise en évidence des polysaccharides sur coupes fines en microscopie électronique. Journal de Microscopie, 6, 987–1018. [Google Scholar]
  61. Yamaguti S. 1971. Synopsis of the Digenetic Trematodes of Vertebrates. Keigaku Publishing Company, Tokyo, Vol. 1, 1074 pp; Vol. II., 349 pl. [Google Scholar]

Cite this article as: Ndiaye PI, Quilichini Y, Séne A, Tkach VV, Bâ CT & Marchand B: Ultrastructural characters of the spermatozoa in Digeneans of the genus Lecithochirium Lühe, 1901 (Digenea, Hemiuridae), parasites of fishes: comparative study of L. microstomum and L. musculus. Parasite, 2014, 21, 49.

All Tables

Table 1.

Spermatological characters in the superfamily of Hemiuroidea (Ndiaye et al. [41] completed).

In the text

All Figures

thumbnailthumbnailthumbnail Figures 1–19.

1. A fragment of the seminal vesicle of Lecithochirium microstomum containing spermatozoa. Scale bar = 2 μm. Spz = spermatozoon, V = seminal vesicle, Vw = seminal vesicle wall.

2–6. Region I of the spermatozoon of Lecithochirium microstomum. Scale bars = 0.2 μm. (2). A longitudinal section of the anterior extremity of the spermatozoon showing the external ornamentation of the plasma membrane. (3). Cross-section in the anterior extremity of the spermatozoon showing the anterior axonemal extremity 1, the external ornamentation of the plasma membrane and some microtubules. (4). Cross-section showing the external ornamentation of the plasma membrane, the anterior axonemal extremity 1 and some singlets of the axoneme 2. (5). Cross-section showing the axoneme 1, the anterior axonemal extremity 2 and the external ornamentation of the plasma membrane. (6). Cross-section with the two axonemes and the external ornamentation of the plasma membrane. Aae1 = anterior extremity of the first axoneme, Aae2 = anterior extremity of the second axoneme, Ase = anterior spermatozoon extremity, Ax1 = first axoneme, Ax2 = second axoneme, B = bulge, Cm = cortical microtubules, Eo = external ornamentation of the plasma membrane, FEo = filamentous ornamentation, S = singlet.

7–12. Cross-sections of Region II of the spermatozoon of Lecithochirium microstomum. Scale bars = 0.2 μm. (7–9). Two axonemes and cortical microtubules. (10). Two axonemes, cortical microtubules and the nucleus. (11). Two axonemes, cortical microtubules, the nucleus and the mitochondrion. (12). One axoneme completely formed, nucleus, mitochondrion, cortical microtubules and the disorganization of the first axoneme. Ax2 = second axoneme, Cm = cortical microtubules, Mt = mitochondrion, N = nucleus, Pae1 = posterior extremity of the first axoneme.

13–14. Cross-section of Region III of the spermatozoon of Lecithochirium microstomum. Scale bar = 0.2 μm. (13). One axoneme, nucleus, mitochondrion and cortical microtubules. (14). One axoneme, nucleus and cortical microtubules. Ax2 = second axoneme, Cm = cortical microtubules, Mt = mitochondrion, N = nucleus.

15–18. Cross-sections of Region IV of the spermatozoon of Lecithochirium microstomum. Scale bars = 0.2 μm. (15). The second axoneme and nucleus. (16). Disorganization of the second axoneme and nucleus. (17). The nucleus surrounded by the doublets of the disorganized axoneme 2. (18). Cross-section in the posterior extremity of the spermatozoon showing only the posterior extremity of the second axoneme. N = nucleus, Pae 2 = posterior extremity of the second axoneme.

19. Transmission electron micrograph of spermatozoa of Lecithochirium microstomum showing glycogen granules (G) revealed by the test of Thiéry. Scale bar = 0.2 μm.
In the text
thumbnailthumbnail Figures 20–37.

20. A fragment of the seminal vesicle of Lecithochirium musculus containing spermatozoa. Scale bar = 2 μm. Spz = spermatozoon, V = seminal vesicle, Vw = seminal vesicle wall.

21–24. Region I of the spermatozoon of Lecithochirium musculus. Scale bars = 0.2 μm. (21). A longitudinal section of the anterior extremity of the spermatozoon showing the external ornamentation of the plasma membrane. (22). Cross-section in the anterior extremity of the spermatozoon showing the anterior extremity of the first axoneme and the external ornamentation of the plasma membrane. (23). Cross-section exhibiting the axoneme 1, the external ornamentation of the plasma membrane and singlets of the second axoneme. (24). Cross-section showing the two axonemes and the external ornamentation of the plasma membrane. Aae1 = anterior extremity of the first axoneme, Ase = anterior spermatozoon extremity, Ax1 = first axoneme, Ax2 = second axoneme, B = bulge, Eo = external ornamentation of the plasma membrane, S = singlet.

25–30. Cross-sections of Region II of the spermatozoon of Lecithochirium musculus. Scale bars = 0.2 μm. (25–26). Two axonemes and some cortical microtubules. (27–28). Two axonemes, cortical microtubules and the nucleus. (29). Two axonemes, cortical microtubules, the nucleus and the mitochondrion. (30). One axoneme, nucleus, mitochondrion, cortical microtubules and the posterior axonemal extremity 1. Ax2 = second axoneme, Cm = cortical microtubules, Mt = mitochondrion, N = nucleus, Pae1 = posterior extremity of the first axoneme.

31–32. Cross-section of Region III of the spermatozoon of Lecithochirium musculus. Scale bars = 0.2 μm. (31). The second axoneme, nucleus, mitochondrion and some cortical microtubules. (32). The second axoneme, nucleus and some microtubules. Ax2 = second axoneme, Cm = cortical microtubules, Mt = mitochondrion, N = nucleus.

33–36. Cross-section of Region IV of the spermatozoon of Lecithochirium musculus. Scale bars = 0.2 μm. (33). Cross-section of the spermatozoon showing the second axoneme, nucleus and one cortical microtubule. (34). Cross-section of the spermatozoon showing the second axoneme disorganized and the nucleus. (35). Cross-section of the spermatozoon showing the nucleus surrounded by doublets from the second axoneme. (36). Cross-section showing the posterior extremity of the spermatozoon with only the posterior extremity of the second axoneme. Cm = cortical microtubules, N = nucleus, Pae 2 = posterior extremity of the second axoneme.

37. Transmission electron micrograph of spermatozoa of Lecithochirium musculus showing glycogen granules (G) revealed by the test of Thiéry. Scale bar = 0.2 μm.
In the text
thumbnail Figure 38.

Schematic reconstruction of the spermatozoon in the genus Lecithochirium: L. musculus (in black), L. microstomum (in black + red). Aae1 = anterior extremity of the first axoneme, Aae2 = anterior extremity of the second axoneme, Ase = anterior spermatozoon extremity, Ax1 = first axoneme, Ax2 = second axoneme, B = bulge, Cm = cortical microtubules, Eo = external ornamentation of the plasma membrane, FEo = filamentous ornamentation, G = granules of glycogen, M = mitochondrion, N = nucleus, Pae1 = posterior extremity of the first axoneme, Pae2 = posterior extremity of the second axoneme, Pm = plasma membrane, Pse = posterior spermatozoon extremity.
In the text

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