TY - JOUR T1 - The somatic female gonad of Cephalobidae (Nematoda): cellular architecture and associated function JF - NematologyNematology Y1 - 2007 A1 - Bert, W. A1 - Vangestel, S. A1 - Houthoofd, W. A1 - Van Gansbeke, R. A1 - Borgonie, G. SP - 285 EP - 297 KW - Acrobeloides KW - Caenorhabditis KW - Caenorhabditis elegans KW - caenorhabditis-elegans KW - CALIFORNIA KW - CELLS KW - CEPHALOBIDAE KW - Cephalobus KW - Chiloplacus KW - cytoskeleton KW - Evolution KW - FAMILY KW - gonad KW - gonoduct KW - HERMAPHRODITE KW - LINEAGES KW - microscopy KW - MODEL KW - Nematoda KW - NEMATODE KW - nematodes KW - paramyosin KW - PHYLOGENETIC SIGNIFICANCE KW - Prionchulus KW - propulsion KW - REDESCRIPTION KW - REPRODUCTIVE-SYSTEM KW - SPERMATHECA KW - THORNE KW - TYLENCHIDA KW - Zeldia AB - The female reproductive system of the free-living nematode family Cephalobidae is examined by means of differential interference contrast, scanning electron and fluorescent microscopy. The model nematode Caenorhabditis elegans and the predatory nematode Prionchulus punctatus are also included in this study; the former mainly to test our results with the very detailed knowledge of this model organism, the latter to provide a representative of the more distantly related Enoplea. In this comparative approach, the analysed gonad structures are discussed with respect to their functional and phylogenetic significance. The general cellular composition of the cephalobid gonad - namely an oviduct comprising two rows of four cells, a distinctly offset spermatheca consisting of 8-16 cells, and a uterus composed of distinct cell rows - differs from all known Nematoda except that of the plant-parasitic Tylenchomorpha. Despite the striking evolutionary conservation of the cellular architecture of the cephalobid gonad there is a complex subcellular specialisation, namely a significant and functionally relevant variation in myofilament organisation, both among Cephalobidae and between major groups of nematodes. We demonstrate the presence of microfilaments that vary in pattern among species and that may play an important role in egg propulsion. The phenomenon of endotokia matricida, in which eggs do not leave the female body, is found to be associated with a massive rupture of the cytoskeleton in the uterus wall. The complexity of the myofibril structure and the associated potential to propagate oocytes actively cannot be solely explained by differences in phylogenetic history, but is also linked to body diameter. In the larger Acrobeloides maximus, the proximal end of the ovary sheath is adorned with 12 distinct longitudinal bands, antibody binding positively for paramyosin, while in the smaller Cephalobus cubaensis myofilament organisation is at random VL - 9 SN - 1388-5545 N1 - Times Cited: 0 Article English Bert, W Univ Ghent, Dept Biol, Nematol Unit, Ledeganckstr 35, B-9000 Ghent, Belgium Cited References Count: 46 197FO BRILL ACADEMIC PUBLISHERS PLANTIJNSTRAAT 2, P O BOX 9000, 2300 PA LEIDEN, NETHERLANDS LEIDEN Part 2 ER - TY - JOUR T1 - Different roads to form the same gut in nematodes JF - Evolution & DevelopmentEvolution & Development Y1 - 2006 A1 - Houthoofd, W. A1 - Willems, M. A1 - Vangestel, S. A1 - Mertens, C. A1 - Bert, W. A1 - Borgonie, G. SP - 362 EP - 369 KW - C-ELEGANS KW - Caenorhabditis KW - Caenorhabditis elegans KW - caenorhabditis-elegans KW - CELLS KW - EMBRYOGENESIS KW - EMBRYONIC-CELL LINEAGE KW - Evolution KW - FATE KW - INDUCTION KW - microscopy KW - MODEL KW - NEMATODE KW - nematodes KW - SPECIFICATION AB - The morphogenesis of a gut from the endoderm has been well studied among the animal kingdom and is also well described in the nematode Caenorhabditis elegans. But are there other ways to build a nematode intestine? Sulston et al. (1983) described a different intestinal cell lineage in the species Panagrellus redivivus and Turbatrix aceti that includes two programmed cell deaths. However, no details are known about the three-dimensional (3D) configuration and the role of the cell deaths. Here, we describe the intestinal morphogenesis of P. redivivus and five other nematode species by means of four-dimensional microscopy, which gives us a 3D representation of gut formation at the cellular level. The morphological pathway of gut formation is highly conserved among these distantly related species. However, we found the P. redivivus pattern in another related species Halicephalobus gingivalis. In this pattern, the intestinal precursors migrate inward in concert with the mesoderm precursors. Based on the observations, we propose a hypothesis that could explain the differences. The positions of the mesoderm precursors create a possible spatial constraint, by which the establishment of bilateral symmetry in the intestine is delayed. This symmetry is corrected by cell migrations; other cells are eliminated and compensated by supplementary cell divisions. This pattern leads to the same result as in the other nematodes: a bilateral symmetrical intestine with nine rings. This illustrates how conserved body plans can be achieved by different developmental mechanisms VL - 8 SN - 1520-541X N1 - Times Cited: 1 Article English Borgonie, G Univ Ghent, Dept Biol, KL Ledeganckstr 35, B-9000 Ghent, Belgium Cited References Count: 40 058HC BLACKWELL PUBLISHING 9600 GARSINGTON RD, OXFORD OX4 2DQ, OXON, ENGLAND OXFORD ER - TY - JOUR T1 - Assessment of the configuration of the posterior cells of the nematode embryo as potential phylogenetic marker JF - Russian Journal of NematologyRussian Journal of Nematology Y1 - 2008 A1 - Vangestel, S. A1 - Houthoofd, W. A1 - Bert, W. A1 - Vanholme, B. A1 - Calderon-Urrea, A. A1 - Willems, M. A1 - Artois, T. A1 - Borgonie, G. SP - 107 EP - 120 KW - Belgium KW - C-ELEGANS EMBRYOS KW - Caenorhabditis KW - Caenorhabditis elegans KW - caenorhabditis-elegans KW - CELLS KW - CLEAVAGE KW - EARLY EMBRYOGENESIS KW - embryology KW - ENOPLIDA KW - Evolution KW - GUT KW - LINEAGE KW - MELOIDOGYNE KW - MOLECULAR PHYLOGENY KW - Nematoda KW - NEMATODE KW - phylogenetic marker KW - PHYLOGENIES KW - phylogeny KW - spatial configuration KW - SPECIFICATION AB - We have reconstructed the evolutionary history of an early developmental character by mapping the configuration of the posterior cells in the early embryo onto the SSU-based molecular phylogeny of Holterman (2006). We have analyzed the early embryonic development of 19 species, complemented with 20 species from the literature, covering representatives in each clade. We show that the Caenorhabditis elegans configuration, found in most species in clade III-X, is the ancestral state for these clades. alternative configurations arose inependently in clade IX, (Diploscapter coronatus), X (Halicephalobus gingivalis), XI (all investigated species) and XII (Meloidogyne incognita). A variable configuration of the posterior cells arose at least twice independently during nematode evolution, once in clade IX (D. coronatus) and once in an ancestor, shared by clade XI and XII and thus can be used as a phylogenetic marker to delineate these clades. Statistical tests based on our data-set show that the presence of a variable configuration is related to developmental tempo and egg shape VL - 16 SN - 0869-6918 N1 - Times Cited: 0 Article English Vangestel, S Univ Ghent, Dept Biol, Nematol Sect, KL Ledeganckstr 35, B-9000 Ghent, Belgium Cited References Count: 55 383BP MYLNEFIELD RESEARCH SERVICES INVERGOWRIE, DUNDEE DD2 5DA, SCOTLAND DUNDEE ER - TY - JOUR T1 - The early embryonic development of the satellite organism Pristionchus pacificus: differences and similarities with Caenorhabditis elegans JF - NematologyNematology Y1 - 2008 A1 - Vangestel, S. A1 - Houthoofd, W. A1 - Bert, W. A1 - Borgonie, G. SP - 301 EP - 312 KW - 4D microscopy KW - Belgium KW - C-ELEGANS KW - Caenorhabditis KW - Caenorhabditis elegans KW - caenorhabditis-elegans KW - cell lineage KW - CELL-CELL INTERACTIONS KW - development KW - EARLY EMBRYOGENESIS KW - EMBRYOGENESIS KW - Evolution KW - FATE KW - INDUCTION KW - LINEAGE KW - microscopy KW - MODEL KW - NEMATODE KW - neodiplogastridae KW - PATTERN-FORMATION KW - PHYLOGENETIC IMPLICATIONS KW - SEQUENCE KW - SPECIFICATION KW - VULVA DEVELOPMENT AB - As a comparative counterpart for the model organism Caenorhabditis elegans, the nematode Pristionchus pacificus was established as a satellite organism to study developmental processes. However, these studies mainly focused on post-embryonic development and little is known about the early embryonic development. Using 4D microscopy we reconstructed the early embryonic cell lineage of 12 individuals of P. pacificus. By analysing several parameters of early development, including the division sequence, the spatial arrangement of blastomeres, the cell cycle patterns of the AB lineage and cell-cell contacts in different cell stages of the embryo, it was shown that the early embryonic development is nearly identical to C. elegans. Known cell-cell contacts necessary for induction of blastomere fates in C. elegans are also present in P pacificus. Thus, the spatio-temporal conditions that would allow possible homologous inductions are present. However, at least one model for blastomere specification seems not to apply to P pacificus since the third division in the AB lineage differs from that of C elegans. Furthermore, naturally occurring variability of early development was demonstrated, which is clearly permitted since there seems to be no influence on further development into an adult worm VL - 10 SN - 1388-5545 N1 - Times Cited: 1 Article English Borgonie, G Univ Ghent, Dept Biol, Nematol Sect, KL Ledeganckstr 35, B-9000 Ghent, Belgium Cited References Count: 47 293NC BRILL ACADEMIC PUBLISHERS PLANTIJNSTRAAT 2, P O BOX 9000, 2300 PA LEIDEN, NETHERLANDS LEIDEN Part 3 ER -