Ultrastructure of sperm development in the free-living marine nematodes of the family Chromadoridae (Chromadorida: Chromadorina)

Nematology ◽  
2000 ◽  
Vol 2 (3) ◽  
pp. 285-296 ◽  
Author(s):  
Vladimir Yushin ◽  
August Coomans
Keyword(s):  
Nuclear Envelope ◽  
Marine Nematodes ◽  
Large Nucleus ◽  
Free Living ◽  
Golgi Bodies ◽  
Microscopie Électronique ◽  
The Family ◽  
Sperm Development ◽  
Sperm Plasma Membrane ◽  
Filamentous Material

AbstractSpermatogenesis 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.La spermatogenèse a été étudiée en microscopie électronique à transmission chez deux espèces de nématodes libres marins (Panduripharynx pacifica et Euchromadora robusta) de la famille des Chromadoridae. Les spermatogonies, chez les deux espèces, sont des cellules indifférenciées avec un grand noyau entouré d'une petite quantité de cytoplasme. Chez P. pacifica, le cytoplasme des spermatocytes contient de nombreux corps de Golgi, des cisternae du RER, des ribosomes, des mitochondries et des corps sphériques denses. Le matériel filamenteux est accumulé dans les spermatides qui contiennent seulement des mitochondries et un noyau fragmenté (ou lobé) dépourvu d'enveloppe nucléaire. Le sperme immature resemble aux dernières spermatides: son aire centrale filamenteuse est entourée par des particules de chromatine et quelques mitochondries. La membrane plasmatique du sperme immature forme des invaginations profondes. Les spermatozoïdes matures, dans l'utérus, sont constitués par un petit corps cellulaire principal (MCB) portant un pseudopode proéminent rempli de filaments de cytosquelette. Le MCB contient un noyau et des mitochondries. La spermatogenèse chez E. robusta (étudiées seulement au niveau des testicules) ressemble à celle décrite chez P. pacifica, mais les spermatocytes d' E. robusta sont le siège d'une activité métabolique plus faible et, par conséquent, une masse plus faible de matériel filamenteux est stockée dans les spermatides et dans le sperme immature. Les spermatozoïdes de P. pacifica et le sperme immature d' E. robusta ont les mêmes caractéristiques ultrastructurales pour des nématodes (nature amiboïde, absence d'axonème, d'acrosome et d'enveloppe nucléaire) mais aucune des organelles aberrantes particuliéres à de nombreux spermes de nématodes (organelles membraneuses, corps fibreux paracrystallins et leurs complexes) n'ont été identifiées pendant le développement du sperme chez les Chromadorides étudiés. Par cet aspect, leur spermatogenèse diffère significativement de celle des Secernentes et des Monhysterides.

Two new species of free-living marine nematodes of the family Oxystominidae Chitwood, 1935 (Enoplida) with a review of the genus Thalassoalaimus de Man, 1893 from the Argentine coast 

Zootaxa ◽  
2017 ◽  
Vol 4250 (4) ◽  
pp. 347
Author(s):  
ANTONELA MARTELLI ◽  
VIRGINIA LO RUSSO ◽  
GABRIELA VILLARES ◽  
CATALINA T. PASTOR DE WARD
Keyword(s):  
New Species ◽  
San Antonio ◽  
Marine Nematodes ◽  
San Jose ◽  
Key To Species ◽  
Free Living ◽  
Rio Negro ◽  
The Family ◽  
Two New Species ◽  
De Man

Two new free-living marine nematodes of the family Oxystominidae are described from San Antonio Bay (Río Negro) and San José Gulf (Chubut). Litinium australis sp. n., is characterized by having a rounded tail, by the first and second crown of cephalic setae with different lengths, gubernaculum with apophysis and by the presence of at least four precloacal papillae; Thalassoalaimus nestori sp. n., is characterized by having a conical tail, cephalic setae equal in length, gubernaculum with rounded and dorso-caudally directed apophysis and two precloacal papillae. An emended diagnosis of the genus Thalassoalaimus and a key to species are given. 

scholarly journals New species ofEpacanthion(Nematoda: Thoracostomopsidae) from Patagonia coast, Río Negro and Chubut, Argentina

2012 ◽  
Vol 93 (4) ◽  
pp. 925-934 ◽  
Author(s):  
V. Lo Russo ◽  
G. Villares ◽  
A. Martelli ◽  
C.T. Pastor de Ward ◽  
C. Harguinteguy
Keyword(s):  
New Species ◽  
Coastal Areas ◽  
The Body ◽  
Cervical Region ◽  
Marine Nematodes ◽  
Free Living ◽  
Rio Negro ◽  
Body Diameter ◽  
The Family ◽  
Short Spicule

Two new free-living marine nematodes belonging to the family Thoracostomopsidae, subfamily Enoplolaiminae and the generaEpacanthionare described from Patagonian coastal areas, Río Negro and Chubut provinces of Argentina. InEpacanthion bicuspidatumsp. nov. the main features are: two cusps on distal mandible end; presence of two rings of eight setae in the cervical region; and eight crown-shaped setae along the body, presence of one supplement distant two cloacal body diameter (cbd) from cloacae, gubernaculum and short spicule.Epacanthion ampullatumsp. nov. is characterized by having a tubular and long pre-cloacal supplement, short spicule, presence of gubernaculum, presence of three long setae on the tip of the tail, the presence of one supplement distant three cbd from cloacae and the presence of two small cusps on the distal end of the mandible.

Systematics and DNA barcoding of free-living marine nematodes with emphasis on tropical desmodorids using nuclear SSU rDNA and mitochondrial COI sequences

Nematology ◽  
2014 ◽  
Vol 16 (8) ◽  
pp. 979-989 ◽  
Author(s):  
Maickel Armenteros ◽  
Ariadna Rojas-Corzo ◽  
Alexei Ruiz-Abierno ◽  
Sofie Derycke ◽  
Thierry Backeljau ◽  
...  
Keyword(s):  
Dna Barcoding ◽  
Sister Group ◽  
Ssu Rdna ◽  
Reference Database ◽  
Cryptic Diversity ◽  
Marine Nematodes ◽  
Free Living ◽  
Mitochondrial Coi ◽  
The Family ◽  
Coi Sequences

The diversity and phylogenetic relationships of the Desmodoridae, a widespread tropical family of free-living marine nematodes, is hitherto poorly known both from molecular and taxonomic points of view. We performed a molecular phylogenetic analysis of marine nematodes to: i) disentangle relationships among tropical desmodorid species; and ii) compare the performance of the nuclear SSU rDNA and mitochondrial COI nucleotide sequences in 42 and 45 nominal species, respectively, to identify species. We generated 27 new sequences of SSU rDNA belonging to five genera not previously sequenced, and 34 new sequences of COI belonging to six genera and four families not previously sequenced. The SSU rDNA tree confirmed the Enoplida to be a monophyletic sister group to the Chromadorida. The family Comesomatidae is a sister group of the Xyalidae within the Monhysterida. Both DNA markers confirmed the congruence between the morphology- and molecular-based phylogenetic inferences for most of the families. Desmodoridae was a monophyletic group, but the relationships within the family could not be recovered; the subfamilies Desmodorinae and Spiriniinae were not monophyletic meanwhile the monophyly of Stilbonematinae was not fully supported due to a few specimens of questionable identity. COI performed better than SSU rDNA to disentangle relationships among closely related species and suggested the presence of cryptic diversity within Desmodoridae. COI is effective to explore cryptic diversity and barcode species within Nematoda, with a possible threshold of genetic distance of 5% between conspecific and interspecific sequences, but DNA barcoding is limited by the poor knowledge of the diversity and taxonomy of the group and the lack of a good reference database of vouchered COI sequences.

Ciliate Hitch-hikers—Nematode ecto-commensals from tropical Australian sea grass meadows

2003 ◽  
Vol 83 (3) ◽  
pp. 445-446 ◽  
Author(s):  
R. Fisher
Keyword(s):  
Marine Nematodes ◽  
Free Living ◽  
The Family ◽  
Sea Grass

The presence of suctorian ciliates attached to the cuticle of heavily ornamented free-living marine nematodes, especially the family Desmodoridae, has been reported. Observations of nematode hosts and their attached ciliates were made from samples extracted from very fine muddy sands of tropical Australian sea grass meadows. Measurements of the point of attachment of the ciliates revealed that they tend to position themselves near the anus/cloaca of the nematode host.

Two new ovoviviparous species of the family Selachinematidae and Sphaerolaimidae (Nematoda, Chromadorida & Monhysterida) from the northern South China Sea

Zootaxa ◽  
2017 ◽  
Vol 4317 (1) ◽  
pp. 95
Author(s):  
SUJING FU ◽  
GUY BOUCHER ◽  
LIZHE CAI
Keyword(s):  
South China Sea ◽  
South China ◽  
Northern South China Sea ◽  
Nematode Species ◽  
Marine Nematodes ◽  
Free Living ◽  
China Sea ◽  
The Family

Two new ovoviviparous nematode species are described from South China Sea. Bendiella vivipara n. sp. belongs to the family Selachinematidae and is characterized by a cuticle with lateral differentiation of 2–4 longitudinal rows of dots, and the presence of 3 papillose precloacal supplements. Parasphaerolaimus jintiani n. sp. is characterized by a cuticle with lateral longitudinal unstriated band extending from about the middle of the pharynx to the anterior two-thirds of the tail and a vulva situated far posteriorly. The importance of ovoviviparity in free living marine nematodes is discussed. 

Ultrastructure of spermatogenesis in the free-living marine nematode Anticoma possjetica (Enoplida: Anticomidae)

Nematology ◽  
2003 ◽  
Vol 5 (5) ◽  
pp. 777-788 ◽  
Author(s):  
Vladimir Yushin
Keyword(s):  
Electron Microscopy ◽  
Nuclear Envelope ◽  
The Other ◽  
Residual Body ◽  
Marine Nematode ◽  
Free Living ◽  
Golgi Bodies ◽  
Late Spermatid ◽  
Mature Spermatozoa

Abstract- Spermatogenesis of the free-living marine nematode Anticoma possjetica was studied with electron microscopy. The spermatocyte cytoplasm is filled with numerous ribosomes, mitochondria, cisternae of RER and Golgi bodies. After completion of meiosis the nucleus of the spermatids is surrounded by a newly formed nuclear envelope. The first membranous organelles (MO) appear in the early spermatids, in the late spermatid they, together with mitochondria, surround the nucleus. The ribosomes, RER and Golgi bodies are concentrated inside the residual body. The nuclei of immature spermatozoa assume a bullet-like shape and are surrounded by mitochondria and a mass of MO. The mature spermatozoa possess a small anterior pseudopod anchoring them to the spermatheca wall. The spermatozoon cytoplasm is filled with densely packed MO interspersed with mitochondria. During spermatogenesis of A. possjetica, no organelles resembling the fibrous bodies (FB) found in the spermatozoa of other nematodes were observed. The ultrastructural peculiarities of spermatogenesis in A. possjetica differentiate it from many of the other nematodes studied, although important similarities with other enoplids (reconstitution of nuclear envelope) and other Enoplia (late MO formation) are present.

Ultrastructure of spermatogenesis in the free-living marine nematode Pontonema vulgare (Enoplida, Oncholaimidae)

2002 ◽  
Vol 80 (8) ◽  
pp. 1371-1382 ◽  
Author(s):  
Vladimir V Yushin ◽  
August Coomans ◽  
Vladimir V Malakhov
Keyword(s):  
Electron Microscopy ◽  
Nuclear Envelope ◽  
Residual Body ◽  
Marine Nematode ◽  
Free Living ◽  
Golgi Bodies ◽  
Main Cell ◽  
Paracrystalline Structure ◽  
Peripheral Cytoplasm ◽  
Large Nucleolus

Spermatogenesis in testes of the free-living marine nematode Pontonema vulgare was studied with electron microscopy. The nucleus of spermatocytes has a large nucleolus; the cytoplasm is filled with numerous ribosomes, mitochondria, cisternae of the rough endoplasmic reticulum (RER), Golgi bodies, and flattened osmiophilic cisternae, which are interpreted as the modified membranous organelles (MO) of the spermatozoa of other nematodes studied. After completion of the second meiotic telophase, the nucleus is surrounded by a newly formed nuclear envelope. Further nucleus transformation includes condensation of the chromatin and shrinkage of the nuclear envelope. The deep infoldings of the nuclear envelope give a starlike shape to the nuclei. The cytoplasm of the early spermatids contains the same organelles as in the late spermatocytes, including MO. Many of the latter assume a cuplike or pocketlike shape. During spermatogenesis the peripheral cytoplasm containing the ribosomes, RER, Golgi bodies, and transparent vesicles moves to one pole of the cell forming the residual body. The main cell body of the late spermatid includes the nucleus, mitochondria, and MO embedded in a dense filamentous matrix. The fibrous bodies (FB) of a paracrystalline structure occur in spermatids throughout their developmental transformations. The central part of the spermatozoa contains a starlike nucleus with a nuclear envelope. The filamentous cytoplasm of the spermatozoa includes mitochondria and MO. The spermatozoa extracted from the testes form numerous long filopodia. The dense filamentous cytoplasm of the spermatozoa is continuous with the content of the filipodia. The reconstitution of the nuclear envelope and separate development of MO and FB described in P. vulgare spermatogenesis are the special characters of enoplid nematodes. The reduced character of FB development and simplified structure of MO differentiate P. vulgare from other nematodes studied.

Four new species of free-living marine nematodes of the family Comesomatidae (Nematoda: Araeolaimida) from coast of Vietnam

Zootaxa ◽  
2013 ◽  
Vol 3608 (7) ◽  
pp. 547-560 ◽  
Author(s):  
VLADIMIR G. GAGARIN
Keyword(s):  
New Species ◽  
Littoral Zone ◽  
Nematode Species ◽  
Valid Species ◽  
Marine Nematodes ◽  
Free Living ◽  
The Family ◽  
Coast Of Vietnam ◽  
Amphidial Fovea

Specimens of four new nematode species of the family Comesomatidae were isolated from the sediments of littoral zone of South China Sea at the coast of Vietnam and described and illustrated. Sabatieria curvispiculata sp. n. is characterized by the long and slender tail, short cephalic setae and strongly curved spicules in males. Setosabatiera orientalis sp. n. is close to S. australis Riera, Nunez, Brito, 2006, but differs from it in the comparatively shorter and more slender tail, small-er number of amphidial fovea turns, greater number of precloacal supplements in males and shape and structure of spic-ules. Dorylaimopsis intermedia sp. n. is morphologically closest to D. mediterranea Grimaldi-de Zio, 1968 and D. magellanense Chen, Vincx, 1968, but differs from both species in the longer outer labial setae and absence of precloacal supplements in males. D. brevispiculata sp. n. is similar to D. turneri Zhang, 1992 and D. coomansi Muthumbi, Soetaert, Vincx, 1977, but differs from both species in the shape of outer labial sensillae and absence of precloacal supplements in males. A pictorial key for determination of valid species in the genus Setosabatieria Rouville, 1903 is given.

Sign in / Sign up

Export Citation Format

Share Document