Ultrastructure of sperm development in the free-living marine nematodes of the family Chromadoridae (Chromadorida: Chromadorina)
Yushin, V.V.; Coomans, A. (2000). Ultrastructure of sperm development in the free-living marine nematodes of the family Chromadoridae (Chromadorida: Chromadorina). Nematology (Leiden) 2(3): 285-296. dx.doi.org/10.1163/156854100509150 In: Nematology (Leiden). Brill: Köln; Leiden; Boston. ISSN 1388-5545; e-ISSN 1568-5411, more |  |
| Keywords | Euchromadora robusta Kulikov, Dashchenko, Koloss & Yushin, 1998 [WoRMS]; Panduripharynx pacifica Belogurov, Daschenko & Fadeeva, 1985 [WoRMS]
Marine/Coastal | | Author keywords | Euchromadora robusta; Panduripharynx pacifica; spermatogenesis |
| Authors | | Top | - Yushin, V.V.
- Coomans, A., more
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| Abstract | Spermatogenesis in two species of free-living marine nematodes from the family Chromadoridae (Panduripharynx pacifica and Euchromadora robusta) was studied electron-microscopically. The spermatogonia of both species are undifferentiated polygonal cells with a large nucleus surrounded by a small amount of cytoplasm. In P. pacifica the cytoplasm of spermatocytes contains many Golgi bodies, cisternae of RER, ribosomes, mitochondria and dense spherical bodies. Filamentous material is accumulated in spermatids, which contain only mitochondria and a fragmented (or lobed) nucleus devoid of the nuclear envelope. The immature sperm resembles the late spermatid: its central filamentous area is surrounded by chromatine particles and occasional mitochondria. The immature sperm plasma membrane forms deep infoldings. Mature spermatozoa from the uterus consist of a small main cell body (MCB) bearing a prominent pseudopod filled with cytoskeleton filaments. The MCB contains a nucleus and mitochondria. Spermatogenesis in E. robusta (studied only in testes) resembles that described for P. pacifica, but spermatocytes of E. robusta show much lower metabolic activity and, as a result, a smaller mass of filamentous material is stored in the spermatids and immature sperm. The spermatozoa of P. pacifica and the immature sperm of E. robusta have the main ultrastructural features characteristic for nematodes (amoeboid nature, absence of axoneme, acrosome and nuclear envelope). No aberrant organelles special for many nematode sperm (membranous organelles, paracrystalline fibrous bodies and their complexes) were found during sperm development of the chromadorids studied. In this respect their spermatogenesis differs significantly from that in secernents and monhysterids. |
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