Germinal granules in archaeocytes of the sponge Oscarella malakhovi Ereskovsky, 2006

Isaeva, V. V.; Akhmadiev, A. V.

doi:10.1134/s1063074011030059

Cited by 6 publications

(3 citation statements)

References 45 publications

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“…Oscarella lobularis , like some other Oscarella species, does not possess archaeocytes in its mesohyl [ 25 , 27 , 48 ]. It is interesting to note that in Oscarella malakhovi , a species that possesses archaeocytes [ 49 ], these cells are thought to be stem cells for the germ cell line [ 50 ]. We show in the present work that during formation of new exopinacoderm and upper parts of inhalant canal (endopinacoderm), the main role is played by pinacocytes and, to a lesser extent, by choanocytes.…”

Section: Discussionmentioning

confidence: 99%

Oscarella lobularis (Homoscleromorpha, Porifera) Regeneration: Epithelial Morphogenesis and Metaplasia

et al. 2015

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Sponges are known to possess remarkable reconstitutive and regenerative abilities ranging from common wounding or body part regeneration to more impressive re-building of a functional body from dissociated cells. Among the four sponge classes, Homoscleromorpha is notably the only sponge group to possess morphologically distinct basement membrane and specialized cell-junctions, and is therefore considered to possess true epithelia. The consequence of this peculiar organization is the predominance of epithelial morphogenesis during ontogenesis of these sponges. In this work we reveal the underlying cellular mechanisms used during morphogenesis accompanying ectosome regeneration in the homoscleromorph sponge model: Oscarella lobularis. We identified three main sources of novel exopinacoderm during the processes of its regeneration and the restoration of functional peripheral parts of the aquiferous system in O. lobularis: (1) intact exopinacoderm surrounding the wound surface, (2) the endopinacoderm from peripheral exhalant and inhalant canals, and (3) the intact choanoderm found on the wound surface. The basic morphogenetic processes during regeneration are the spreading and fusion of epithelial sheets that merge into one continuous epithelium. Transdifferentiation of choanocytes into exopinacocytes is also present. Epithelial-mesenchymal transition is absent during regeneration. Moreover, we cannot reveal any other morphologically distinct pluripotent cells. In Oscarella, neither blastema formation nor local dedifferentiation and proliferation have been detected, which is probably due to the high morphogenetic plasticity of the tissue. Regeneration in O. lobularis goes through cell transdifferentiation and through the processes, when lost body parts are replaced by the remodeling of the remaining tissue. Morphogenesis during ectosome regeneration in O. lobularis is correlated with its true epithelial organization. Knowledge of the morphological basis of morphogenesis during Oscarella regeneration could have important implications for our understanding of the diversity and evolution of regeneration mechanisms in metazoans, and is a strong basis for future investigations with molecular-biological approaches.

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Section: Discussionmentioning

confidence: 99%

Oscarella lobularis (Homoscleromorpha, Porifera) Regeneration: Epithelial Morphogenesis and Metaplasia

et al. 2015

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“…2018 ). They have also been discovered in archaeocytes ( Isaeva and Akhmadieva 2011 ), reinforcing the idea that some stem cells in the adult sponge could potentially be predetermined for the germline. Here, we observed potential nuage in oocytes of G. macandrewii ( fig.…”

Section: Resultsmentioning

confidence: 74%

The Molecular Machinery of Gametogenesis inGeodiaDemosponges (Porifera): Evolutionary Origins of a Conserved Toolkit across Animals

Koutsouveli

Cárdenas

Santodomingo

et al. 2020

Molecular Biology and Evolution

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All animals are capable of undergoing gametogenesis. The ability of forming haploid cells from diploid cells through meiosis and recombination appeared early in eukaryotes, while further gamete differentiation is mostly a metazoan signature. Morphologically, the gametogenic process presents many similarities across animal taxa, but little is known about its conservation at the molecular level. Porifera are the earliest divergent animals and therefore are an ideal phylum to understand evolution of the gametogenic toolkits. While sponge gametogenesis is well known at the histological level, the molecular toolkits for gamete production are largely unknown. Our goal was to identify the genes and their expression levels which regulate oogenesis and spermatogenesis in five gonochoristic and oviparous species of the genus Geodia, using both RNAseq and proteomic analyses. In the early stages of both female and male gametogenesis, genes involved in germ cell fate and cell-renewal were upregulated. Then, molecular signals involved in retinoic acid pathway could trigger the meiotic processes. During later stages of oogenesis, female sponges expressed genes involved in cell growth, vitellogenesis and extracellular matrix reassembly, which are conserved elements of oocyte maturation in Metazoa. Likewise, in spermatogenesis, genes regulating the whole meiotic cycle, chromatin compaction, and flagellum axoneme formation that are common across Metazoa, were overexpressed in our sponges. Finally, molecular signals possibly related to sperm capacitation were identified during late stages of spermatogenesis for the first time in Porifera. In conclusion, the activated molecular toolkit during gametogenesis in sponges was remarkably similar to that deployed during gametogenesis in vertebrates.

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“…2; Rinkevich et al ., 2009; Wagner et al ., 2011). Emblematic structures in many of these ASCs are the so‐called chromatoid bodies [reported in neoblasts, i‐cells and archaeocytes, as well as most recently in a small pool of notochord cells in cephalochordates (Rossi et al ., 2008; Isaeva et al ., 2009; Isaeva & Akhmadiev, 2011; Holland & Somorjai, 2020)] – electron‐dense aggregates often adjacent to the nuclear envelope that resemble the germline granules of vertebrates and insects.…”

Section: The Wide Range Of Metazoan Asc Morphotypesmentioning

confidence: 99%

A pan‐metazoan concept for adult stem cells: the wobbling Penrose landscape

et al. 2021

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Adult stem cells (ASCs) in vertebrates and model invertebrates (e.g. Drosophila melanogaster) are typically long‐lived, lineage‐restricted, clonogenic and quiescent cells with somatic descendants and tissue/organ‐restricted activities. Such ASCs are mostly rare, morphologically undifferentiated, and undergo asymmetric cell division. Characterized by ‘stemness’ gene expression, they can regulate tissue/organ homeostasis, repair and regeneration. By contrast, analysis of other animal phyla shows that ASCs emerge at different life stages, present both differentiated and undifferentiated phenotypes, and may possess amoeboid movement. Usually pluri/totipotent, they may express germ‐cell markers, but often lack germ‐line sequestering, and typically do not reside in discrete niches. ASCs may constitute up to 40% of animal cells, and participate in a range of biological phenomena, from whole‐body regeneration, dormancy, and agametic asexual reproduction, to indeterminate growth. They are considered legitimate units of selection. Conceptualizing this divergence, we present an alternative stemness metaphor to the Waddington landscape: the ‘wobbling Penrose’ landscape. Here, totipotent ASCs adopt ascending/descending courses of an ‘Escherian stairwell’, in a lifelong totipotency pathway. ASCs may also travel along lower stemness echelons to reach fully differentiated states. However, from any starting state, cells can change their stemness status, underscoring their dynamic cellular potencies. Thus, vertebrate ASCs may reflect just one metazoan ASC archetype.

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Germinal granules in archaeocytes of the sponge Oscarella malakhovi Ereskovsky, 2006

Cited by 6 publications

References 45 publications

Oscarella lobularis (Homoscleromorpha, Porifera) Regeneration: Epithelial Morphogenesis and Metaplasia

Oscarella lobularis (Homoscleromorpha, Porifera) Regeneration: Epithelial Morphogenesis and Metaplasia

The Molecular Machinery of Gametogenesis inGeodiaDemosponges (Porifera): Evolutionary Origins of a Conserved Toolkit across Animals

A pan‐metazoan concept for adult stem cells: the wobbling Penrose landscape

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