The development of Spongilla lacustris from the oocyte to the free larva (Porifera, Spongillidae)

Saller, Uwe; Weissenfels, Norbert

doi:10.1007/bf00312280

Cited by 24 publications

(20 citation statements)

References 6 publications

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“…In the freshwater spongillids, sclerocytes and pinacocytes are the first cells to differentiate in the embryo (Saller and Weissenfels, 1985;Saller, 1988). In Ephydatia fluviatilis, spicules form before the larval cavity develops, and remain scattered throughout the embryo under the ciliated epithelial layer.…”

Section: Differentiation Of Scleroblastsmentioning

confidence: 99%

“…In Ephydatia fluviatilis, spicules form before the larval cavity develops, and remain scattered throughout the embryo under the ciliated epithelial layer. In Spongilla lacustris, the sclerocytes aggregate towards the posterior pole of the embryo and become embedded in spongin in the free-swimming larva (Saller and Weissenfels, 1985).…”

Section: Differentiation Of Scleroblastsmentioning

confidence: 99%

“…In sponges with a variety of spicule types, larvae often lack some of the adult spicules; in particular, microscleres are frequently absent. Furthermore, in only a few larvae are the spicules already embedded in spongin, a secondary organization of the skeleton that is a permanent structure in the juvenile (e.g., Saller and Weissenfels, 1985). In most larvae the spicules are either randomly distributed or are aggregated at the posterior pole, and in no way illustrate the characteristic architecture of the skeleton of the adult sponge.…”

Section: Introductionmentioning

confidence: 98%

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Comparative study of spiculogenesis in demosponge and hexactinellid larvae

Leys

2003

Microscopy Res & Technique

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Spicule deposition was studied by electron microscopy in fixed embryos and larvae of the haplosclerid sponge Reniera sp. and the hexactinellid Oopsacas minuta. Spicules form in centrally located vacuoles within cells and within syncytia, as in the adult sponges. In Reniera, scleroblasts differentiate from micromeres prior to gastrulation. At gastrulation the scleroblasts migrate to the periphery of the embryo and commence spicule deposition around a hexagonal axial filament. Sclerocytes have numerous pseudopodia and migrate to the posterior pole where they become aligned along the antero-posterior axis in the free-swimming larva. Reniera larvae possess some 40-50 oxeas, each 70-75 microm long and 1 microm wide. Mature Oopsacas larvae have up to 14 stauractin spicules, which are produced on a rectangular axial filament in tissues that lie under the smooth epithelium at the posterior pole of the larva. Young sclerocytes have many pseudopodia. The 4-rayed spicules elongate along both the antero-posterior and medial axes, until the longitudinal rays become anchored in a lipid-filled cytoplasm at the anterior of the larva and the lateral rays intersect around the midline. The length of the transverse rays of the stauractins in free-swimming larvae are 27-45 microm each, while the length of the two longitudinal rays is 40-80 microm. Although spicule deposition begins in cells with a similar morphology in both cellular and syncytial sponges, the elaboration and organization of the spicules differ markedly in cellular and syncytial sponges and appear to be an outcome of the very distinct cellular differentiation and larval morphogenesis that occur in each of these groups.

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Section: Differentiation Of Scleroblastsmentioning

confidence: 99%

Section: Differentiation Of Scleroblastsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

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Comparative study of spiculogenesis in demosponge and hexactinellid larvae

Leys

2003

Microscopy Res & Technique

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“…Formation of gemmules in freshwater sponges is fairly studied (Rasmont 1970, Simpson 1984, and references therein; Saller & Weissenfels 1985;Fell 1993, and references therein). Tolerance of gemmules to various conditions and the germination of gemmules though have been well studied (Simpson & Fell 1974;Harsha et al 1983;Rader 1984;Simpson 1984;Fell 1993, and references therein;Pronzato et al 1993;Pronzato & Manconi, 1995;Loomis et al 1996;Reiswig & Miller 1998;Gugel 2001).…”

Section: Discussionmentioning

confidence: 99%

Taxonomy of freshwater sponges of Maharashtra, India, with illustrated descriptions and notes on ecology and habitats (Porifera: Spongillida: Spongillidae)

Jakhalekar¹,

Ghate²

2016

Zootaxa

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We present additional taxonomic descriptions, with Scanning Electron Microscopy (SEM) illustrations, field observations documented by colour photographs, and notes on habitats and ecology of Corvospongilla ultima (Annandale), Eunapius crassissimus (Annandale), Stratospongilla bombayensis (Carter), S. gravelyi (Annandale) and S. indica (Annandale) from recent sponge collections made in western Maharashtra, India. Stratospongilla gravelyi is rediscovered after a century, and along with it, C. ultima and S. indica are illustrated with SEM images for the first time, unequivocally differentiating these two species. Additional taxonomic, ecological data and illustrations of Corvospongilla lapidosa (Annandale), Dosilia plumosa (Carter), Ephydatia meyeni (Carter), Eunapius carteri (Bowerbank) and Radiospongilla cerebellata (Bowerbank) are also provided to supplement the previously published SEM illustrations. All ten spongillid species treated here were originally described from India and three of them are known to be endemic to the Indian region. Present study is the first re-examination of these Indian spongillid species using SEM, providing greater resolution of their important taxonomic characters and careful documentation of their habitats.

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“…Archeocytes are mesenchymal pluripotent stem cells that can freely migrate throughout the sponge body, and are largely considered to be key components of regeneration in sponges (Simpson, 1984). In general, they are capable of differentiating into all cell types in the sponge body, including gametes (Simpson, 1984;Saller and Weissenfels, 1985;Saller, 1988;Kaye, 1991;Ereskovsky, 2010). They are also an important part of development in sponges, with metamorphosis in many species largely involving the movement and differentiation of archeocytes (Bergquist and Green, 1977;Kaye and Reiswig, 1991b;Ereskovsky, 2010;Nakanishi et al, 2014;Sogabe et al, 2016).…”

Section: The Stem Cell System Of Spongesmentioning

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 development of Spongilla lacustris from the oocyte to the free larva (Porifera, Spongillidae)

Cited by 24 publications

References 6 publications

Comparative study of spiculogenesis in demosponge and hexactinellid larvae

Comparative study of spiculogenesis in demosponge and hexactinellid larvae

Taxonomy of freshwater sponges of Maharashtra, India, with illustrated descriptions and notes on ecology and habitats (Porifera: Spongillida: Spongillidae)

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

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