The spermatogenesis of Ephydatia fluviatilis (Porifera)

Paulus, Wolfgang; Weissenfels, Norbert

doi:10.1007/bf00312204

Cited by 48 publications

(24 citation statements)

References 8 publications

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“…However in some demosponges the ultrastructural data give evidence of the origin of spermatozoa from choanocytes (Tuzet et al 1970;Diaz et al 1973;Diaz & Connes, 1980;Gaino et al 1984Gaino et al , 1986Paulus & Weissenfels 1986;Paulus 1989;Barthel & Detmar 1990;Kaye & Reiswig 1991;Boury-Esnault & Jamieson 1999;Usher et al 2004), even though this feature is still controversial. Indeed, some observations suggest that archaeocytes may be at the origin of the germinal cell line ( Hoppe & Reichert 1987;Ilan 1995).…”

Section: Discussionmentioning

confidence: 99%

Some steps of spermatogenesis inHalichondria semitubulosa(Demospongiae, Halichondriidae)

Gaino

Lepore

Rebora

et al. 2007

Italian Journal of Zoology

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Spermatogenesis of the marine sponge Halichondria semitubulosa (formerly Pellina semitubulosa) has been investigated at the ultrastructural level. This process can be observed in March when, among the choanocyte chambers of the aquiferous system, spermatic cysts are visible. They are delimited by pinacocyte-like cells and include elements in progressive development: spermatocytes of the first and second order, spermatids and spermatozoa. The early phase of spermatogenesis was not detected. Spermatocytes of the first order show an elongated shape, several small mitochondria and patched chromatin; spermatocytes of the second order, frequently connected by bridges, show denser chromatin, a single large mitochondrion with numerous tightly adherent cristae, glycogen, and round-shaped inclusions with a central electron-dense core. In the spermatids the chromatin tends to be packed in the central region. Spermatozoa have a uniformly dense nucleus in close association with the large mitochondrion. Sperm maturation takes place synchronously within the same cyst but asynchronously within the same specimen.

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Section: Discussionmentioning

confidence: 99%

Some steps of spermatogenesis inHalichondria semitubulosa(Demospongiae, Halichondriidae)

Gaino

Lepore

Rebora

et al. 2007

Italian Journal of Zoology

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“…They were observed in almost all species of Demospongiae that had their spermatogenesis studied (e.g. Tuzet et al 1970;Paulus and Weissenfels 1986;Paulus 1989;Riesgo et al 2007b;Riesgo and Maldonado 2009b), but they were not found in P. magna. Nonetheless, the sequential divisions and the maintenance of cytoplasmic bridges between secondary spermatocytes after their division (Figs.…”

Section: Spermatocytogenesismentioning

confidence: 99%

“…4h, 5f, g) could be seen as evidences for meiosis in these gametes. These characteristics have been utilised by other authors to support the occurrence of reduction division in Porifera and other Metazoa (Reiswig 1983;Gaino et al 1984;Paulus and Weissenfels 1986;Riesgo et al 2007a). …”

Section: Spermatocytogenesismentioning

confidence: 99%

Oogenesis and spermatogenesis in Paraleucilla magna (Porifera, Calcarea)

Lanna

Klautau

2010

Zoomorphology

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Gametogenesis in Calcarea is still poorly known; therefore, in this work, we describe the gametogenesis of Paraleucilla magna (Porifera, Calcarea) using light and electron microscopy. Male and female gametes derived from choanocytes. Oocytes grew inside a follicle-like structure composed of pinacocyte-like cells and choanocytes. They were nourished through nutrient transfer from nurse cells and through bacteria phagocytosis, which was never documented for a calcarean species. Mature oocytes were typical, spherical, with nucleolated nuclei and a cytoplasm filled with different types of inclusions and digestive vesicles. Nuage was also found. Spermatogenesis occurred in the lumen of differentiated choanocyte chambers, and spermatic cysts were never formed. Spherical spermatogonia without flagellum or collar were derived from hourglass-shaped primordial germ cells. Spermatozoa were of the 'aberrant type', showed a compact electron-dense nucleus and a homogeneous granulated body in its cytoplasm. The gametogenesis of P. magna is similar to what has been observed for other Porifera and Eumetazoa.

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“…Since sponges have highly variable regenerative capacities, which can influence growth form characteristics (e.g. branching, encrusting, and cryptic) and susceptibility to disturbance (Wulff, 2006a), the specific processes involved in this stem cell system may be variable between species as well (Paulus and Weissenfels, 1986;Borisenko et al, 2015). The stem cell system in A. queenslandica appears to be an inherently dynamic system that relies on context-specific regulation of proliferation and transdifferentiation of choanocytes and archeocytes.…”

Section: Choanocytes Are An Essential Part Of the Amphimedon Stem Celmentioning

confidence: 99%

“…Archeocytes are multifunctional, amoebocytic cells that are pluripotent and capable of self-renewal; they are likely the predominant stem cell in sponges (De Sutter and Van de Vyver, 1977;Müller et al, 2006;Funayama, 2008Funayama, , 2010Okamoto et al, 2012). Choanocytes are also highly proliferative and can transdifferentiate into somatic and germ cells in a range of contexts including tissue regeneration, juvenile growth and remodeling, and sexual reproduction (Simpson, 1984;Paulus and Weissenfels, 1986;Leys and Ereskovsky, 2006;Funayama, 2010;Alexander et al, 2014;Nakanishi et al, 2014;Borisenko et al, 2015;Ereskovsky et al, 2015). Unlike many other metazoan stem cells, both archeocytes and choanocytes have additional specializations and physiological functions, including the capture of food by choanocytes and transportation of nutrients by archeocytes (Simpson, 1984;Funayama et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

The biology of choanocytes and choanocyte chambers and their role in the sponge stem cell system

Sogabe¹

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Metazoan multicellularity required the evolution of cellular processes such as cell differentiation, cell-cell adhesion and communication, along with complex gene regulatory networks and the emergence of a stem cell system. Choanocytes, the collared feeding cells in sponges, have been extensively compared to choanoflagellates, the closest sister group to metazoans due to their morphological similarities and their capacity to form multicellular structures. Recently available genomic and transcriptomic data alongside observational studies on the multicellular colonies in choanoflagellate Salpingoeca rosetta, revealed many genes shared with metazoans are upregulated only when the S. rosetta cells form colonies, while there has been little progress made on understanding the development of sponge choanocyte chambers. Choanocytes have also been suggested as playing a part in the sponge stem cell system, but again, there is limited knowledge on their general biology. To expand our understanding on this unique feeding cell that has potential stem cell capacities as well as a long-suggested homology with a closely related unicellular holozoan, I investigated molecular mechanisms underlying the development and maintenance of choanocyte chambers in the demosponge Amphimedon queenslandica.During my PhD, I have documented the formation and maintenance of choanocyte chambers in detail using cell trackers and proliferation assays, showing their dynamic nature in the sponge body as part of the stem cell system. Contrary to previous studies in sponges as well as choanoflagellates, I found that choanocyte chamber development is not always clonal, and a chamber is not always comprised of a clonal cell population. After metamorphosis, choanocytes in these chambers are also capable of dedifferentiating into archeocytes, which can subsequently differentiate into multiple cell types including new choanocyte chambers. I propose that choanocyte chambers in A. queenslandica are playing a central role in the stem cell system, increasing and maintaining the stem cell population. I have also identified genes uniquely expressed in choanocytes, as well as archeocytes (primary stem cells) and pinacocytes (epithelial cells) by manually isolating these cell types from adult sponges, which was sequenced using CEL-Seq. From this, I have obtained a reliable transcriptome for three major cell types comprising the sponge body plan. A number of analyses on the A. queenslandica choanocyte transcriptome and publicly available choanoflagellate datasets, show no strong evidence of a shared gene repertoire between choanocytes and choanoflagellates. This thesis provides a detailed documentation of choanocyte chambers and their biology in the sponge body, along with developing a number of lab-based III techniques and cell-type specific transcriptomes to be utilized for further investigation on the sponge stem cell system and the evolution of metazoan multicellularity.

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The spermatogenesis of Ephydatia fluviatilis (Porifera)

Cited by 48 publications

References 8 publications

Some steps of spermatogenesis inHalichondria semitubulosa(Demospongiae, Halichondriidae)

Some steps of spermatogenesis inHalichondria semitubulosa(Demospongiae, Halichondriidae)

Oogenesis and spermatogenesis in Paraleucilla magna (Porifera, Calcarea)

The biology of choanocytes and choanocyte chambers and their role in the sponge stem cell system

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