1
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Ruperti F, Becher I, Stokkermans A, Wang L, Marschlich N, Potel C, Maus E, Stein F, Drotleff B, Schippers KJ, Nickel M, Prevedel R, Musser JM, Savitski MM, Arendt D. Molecular profiling of sponge deflation reveals an ancient relaxant-inflammatory response. Curr Biol 2024; 34:361-375.e9. [PMID: 38181793 DOI: 10.1016/j.cub.2023.12.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 11/03/2023] [Accepted: 12/07/2023] [Indexed: 01/07/2024]
Abstract
A hallmark of animals is the coordination of whole-body movement. Neurons and muscles are central to this, yet coordinated movements also exist in sponges that lack these cell types. Sponges are sessile animals with a complex canal system for filter-feeding. They undergo whole-body movements resembling "contractions" that lead to canal closure and water expulsion. Here, we combine live 3D optical coherence microscopy, pharmacology, and functional proteomics to elucidate the sequence and detail of shape changes, the tissues and molecular physiology involved, and the control of these movements. Morphometric analysis and targeted perturbation suggest that the movement is driven by the relaxation of actomyosin stress fibers in epithelial canal cells, which leads to whole-body deflation via collapse of the incurrent and expansion of the excurrent canal system. Thermal proteome profiling and quantitative phosphoproteomics confirm the control of cellular relaxation by an Akt/NO/PKG/PKA pathway. Agitation-induced deflation leads to differential phosphorylation of proteins forming epithelial cell junctions, implying their mechanosensitive role. Unexpectedly, untargeted metabolomics detect a concomitant decrease in antioxidant molecules during deflation, reflecting an increase in reactive oxygen species. Together with the secretion of proteinases, cytokines, and granulin, this indicates an inflammation-like state of the deflating sponge reminiscent of vascular endothelial cells experiencing oscillatory shear stress. These results suggest the conservation of an ancient relaxant-inflammatory response of perturbed fluid-carrying systems in animals and offer a possible mechanism for whole-body coordination through diffusible paracrine signals and mechanotransduction.
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Affiliation(s)
- Fabian Ruperti
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany; Collaboration for joint Ph.D. degree between EMBL and Heidelberg University, Faculty of Biosciences 69117 Heidelberg, Germany
| | - Isabelle Becher
- Genome Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | | | - Ling Wang
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany.
| | - Nick Marschlich
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany; Centre for Organismal Studies (COS), University of Heidelberg, 69120 Heidelberg, Germany
| | - Clement Potel
- Genome Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Emanuel Maus
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Frank Stein
- Proteomics Core Facility, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Bernhard Drotleff
- Metabolomics Core Facility, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Klaske J Schippers
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Michael Nickel
- Bionic consulting Dr. Michael Nickel, 71686 Remseck am Neckar, Germany
| | - Robert Prevedel
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany; Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Jacob M Musser
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520, USA.
| | - Mikhail M Savitski
- Genome Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany; Proteomics Core Facility, European Molecular Biology Laboratory, 69117 Heidelberg, Germany.
| | - Detlev Arendt
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany; Centre for Organismal Studies (COS), University of Heidelberg, 69120 Heidelberg, Germany.
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2
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Ruperti F, Becher I, Stokkermans A, Wang L, Marschlich N, Potel C, Maus E, Stein F, Drotleff B, Schippers K, Nickel M, Prevedel R, Musser JM, Savitski MM, Arendt D. Molecular profiling of sponge deflation reveals an ancient relaxant-inflammatory response. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.02.551666. [PMID: 37577507 PMCID: PMC10418225 DOI: 10.1101/2023.08.02.551666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
A hallmark of animals is the coordination of whole-body movement. Neurons and muscles are central to this, yet coordinated movements also exist in sponges that lack these cell types. Sponges are sessile animals with a complex canal system for filter-feeding. They undergo whole-body movements resembling "contractions" that lead to canal closure and water expulsion. Here, we combine 3D optical coherence microscopy, pharmacology, and functional proteomics to elucidate anatomy, molecular physiology, and control of these movements. We find them driven by the relaxation of actomyosin stress fibers in epithelial canal cells, which leads to whole-body deflation via collapse of the incurrent and expansion of the excurrent system, controlled by an Akt/NO/PKG/A pathway. A concomitant increase in reactive oxygen species and secretion of proteinases and cytokines indicate an inflammation-like state reminiscent of vascular endothelial cells experiencing oscillatory shear stress. This suggests an ancient relaxant-inflammatory response of perturbed fluid-carrying systems in animals.
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Affiliation(s)
- Fabian Ruperti
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
- Collaboration for joint Ph.D. degree between EMBL and Heidelberg University, Faculty of Biosciences 69117 Heidelberg, Germany
| | - Isabelle Becher
- Genome Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | | | - Ling Wang
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Nick Marschlich
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
- Centre for Organismal Studies (COS), University of Heidelberg, 69120 Heidelberg, Germany
| | - Clement Potel
- Genome Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Emanuel Maus
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Frank Stein
- Proteomics Core Facility, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Bernhard Drotleff
- Metabolomics Core Facility, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Klaske Schippers
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Michael Nickel
- Bionic Consulting Dr. Michael Nickel, 71686 Remseck am Neckar, Germany
| | - Robert Prevedel
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Jacob M Musser
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520, USA
| | - Mikhail M Savitski
- Genome Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
- Proteomics Core Facility, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Detlev Arendt
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
- Centre for Organismal Studies (COS), University of Heidelberg, 69120 Heidelberg, Germany
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3
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Santini S, Schenkelaars Q, Jourda C, Duchesne M, Belahbib H, Rocher C, Selva M, Riesgo A, Vervoort M, Leys SP, Kodjabachian L, Le Bivic A, Borchiellini C, Claverie JM, Renard E. The compact genome of the sponge Oopsacas minuta (Hexactinellida) is lacking key metazoan core genes. BMC Biol 2023; 21:139. [PMID: 37337252 DOI: 10.1186/s12915-023-01619-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 05/09/2023] [Indexed: 06/21/2023] Open
Abstract
BACKGROUND Explaining the emergence of the hallmarks of bilaterians is a central focus of evolutionary developmental biology-evodevo-and evolutionary genomics. For this purpose, we must both expand and also refine our knowledge of non-bilaterian genomes, especially by studying early branching animals, in particular those in the metazoan phylum Porifera. RESULTS We present a comprehensive analysis of the first whole genome of a glass sponge, Oopsacas minuta, a member of the Hexactinellida. Studying this class of sponge is evolutionary relevant because it differs from the three other Porifera classes in terms of development, tissue organization, ecology, and physiology. Although O. minuta does not exhibit drastic body simplifications, its genome is among the smallest of animal genomes sequenced so far, and surprisingly lacks several metazoan core genes (including Wnt and several key transcription factors). Our study also provides the complete genome of a symbiotic Archaea dominating the associated microbial community: a new Thaumarchaeota species. CONCLUSIONS The genome of the glass sponge O. minuta differs from all other available sponge genomes by its compactness and smaller number of encoded proteins. The unexpected loss of numerous genes previously considered ancestral and pivotal for metazoan morphogenetic processes most likely reflects the peculiar syncytial tissue organization in this group. Our work further documents the importance of convergence during animal evolution, with multiple convergent evolution of septate-like junctions, electrical-signaling and multiciliated cells in metazoans.
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Affiliation(s)
- Sébastien Santini
- Aix Marseille Univ, CNRS, IGS, UMR 7256, IMM, IM2B, IOM, Marseille, France
| | - Quentin Schenkelaars
- Aix Marseille Univ, Avignon Univ, CNRS, IRD, IMBE, Marseille, France
- Institut Jacques Monod, CNRS, UMR 7592, Univ Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Cyril Jourda
- Aix Marseille Univ, CNRS, IGS, UMR 7256, IMM, IM2B, IOM, Marseille, France
- CIRAD, UMR PVBMT, La Réunion, France
| | - Marc Duchesne
- Department of Biological Sciences, University of Alberta, Edmonton, AB, T6G 2E9, Canada
| | - Hassiba Belahbib
- Aix Marseille Univ, CNRS, IGS, UMR 7256, IMM, IM2B, IOM, Marseille, France
| | - Caroline Rocher
- Aix Marseille Univ, Avignon Univ, CNRS, IRD, IMBE, Marseille, France
| | - Marjorie Selva
- Aix Marseille Univ, Avignon Univ, CNRS, IRD, IMBE, Marseille, France
| | - Ana Riesgo
- Department of Biodiversity and Evolutionary Biology, Madrid, Spain
- Department of Life Sciences, Natural History Museum of London, London, SW7 5BD, UK
| | - Michel Vervoort
- Institut Jacques Monod, CNRS, UMR 7592, Univ Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Sally P Leys
- Department of Biological Sciences, University of Alberta, Edmonton, AB, T6G 2E9, Canada
| | - Laurent Kodjabachian
- Aix Marseille Univ, CNRS, IBDM, UMR 7288, Turing Center for Living Systems, Marseille, France
| | - André Le Bivic
- Aix Marseille Univ, CNRS, IBDM, UMR 7288, Marseille, France
| | | | | | - Emmanuelle Renard
- Aix Marseille Univ, Avignon Univ, CNRS, IRD, IMBE, Marseille, France.
- Aix Marseille Univ, CNRS, IBDM, UMR 7288, Marseille, France.
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4
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Penesyan A, Paulsen IT, Kjelleberg S, Gillings MR. Three faces of biofilms: a microbial lifestyle, a nascent multicellular organism, and an incubator for diversity. NPJ Biofilms Microbiomes 2021; 7:80. [PMID: 34759294 PMCID: PMC8581019 DOI: 10.1038/s41522-021-00251-2] [Citation(s) in RCA: 84] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 10/12/2021] [Indexed: 01/12/2023] Open
Abstract
Biofilms are organised heterogeneous assemblages of microbial cells that are encased within a self-produced matrix. Current estimates suggest that up to 80% of bacterial and archaeal cells reside in biofilms. Since biofilms are the main mode of microbial life, understanding their biology and functions is critical, especially as controlling biofilm growth is essential in industrial, infrastructure and medical contexts. Here we discuss biofilms both as collections of individual cells, and as multicellular biological individuals, and introduce the concept of biofilms as unique incubators of diversity for the microbial world.
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Affiliation(s)
- Anahit Penesyan
- Department of Biological Sciences, Faculty of Science and Engineering, Macquarie University, Sydney, NSW, 2109, Australia.
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, NSW, 2109, Australia.
- Department of Molecular Sciences, Faculty of Science and Engineering, Macquarie University, Sydney, NSW, 2109, Australia.
| | - Ian T Paulsen
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, NSW, 2109, Australia
- Department of Molecular Sciences, Faculty of Science and Engineering, Macquarie University, Sydney, NSW, 2109, Australia
| | - Staffan Kjelleberg
- Singapore Centre for Environmental Life Sciences Engineering, 60 Nanyang Drive, SBS-01N-27, Singapore, 637551, Singapore
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551, Singapore
- School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Michael R Gillings
- Department of Biological Sciences, Faculty of Science and Engineering, Macquarie University, Sydney, NSW, 2109, Australia
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, NSW, 2109, Australia
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5
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Jékely G, Godfrey-Smith P, Keijzer F. Reafference and the origin of the self in early nervous system evolution. Philos Trans R Soc Lond B Biol Sci 2021; 376:20190764. [PMID: 33550954 PMCID: PMC7934971 DOI: 10.1098/rstb.2019.0764] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/07/2020] [Indexed: 12/20/2022] Open
Abstract
Discussions of the function of early nervous systems usually focus on a causal flow from sensors to effectors, by which an animal coordinates its actions with exogenous changes in its environment. We propose, instead, that much early sensing was reafferent; it was responsive to the consequences of the animal's own actions. We distinguish two general categories of reafference-translocational and deformational-and use these to survey the distribution of several often-neglected forms of sensing, including gravity sensing, flow sensing and proprioception. We discuss sensing of these kinds in sponges, ctenophores, placozoans, cnidarians and bilaterians. Reafference is ubiquitous, as ongoing action, especially whole-body motility, will almost inevitably influence the senses. Corollary discharge-a pathway or circuit by which an animal tracks its own actions and their reafferent consequences-is not a necessary feature of reafferent sensing but a later-evolving mechanism. We also argue for the importance of reafferent sensing to the evolution of the body-self, a form of organization that enables an animal to sense and act as a single unit. This article is part of the theme issue 'Basal cognition: multicellularity, neurons and the cognitive lens'.
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Affiliation(s)
- Gáspár Jékely
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
| | - Peter Godfrey-Smith
- School of History and Philosophy of Science, University of Sydney, New South Wales 2006, Australia
| | - Fred Keijzer
- Department of Theoretical Philosophy, University of Groningen, Groningen, The Netherlands
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6
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Stevenson A, Archer SK, Schultz JA, Dunham A, Marliave JB, Martone P, Harley CDG. Warming and acidification threaten glass sponge Aphrocallistes vastus pumping and reef formation. Sci Rep 2020; 10:8176. [PMID: 32424237 PMCID: PMC7235243 DOI: 10.1038/s41598-020-65220-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 04/30/2020] [Indexed: 11/09/2022] Open
Abstract
The glass sponge Aphrocallistes vastus contributes to the formation of large reefs unique to the Northeast Pacific Ocean. These habitats have tremendous filtration capacity that facilitates flow of carbon between trophic levels. Their sensitivity and resilience to climate change, and thus persistence in the Anthropocene, is unknown. Here we show that ocean acidification and warming, alone and in combination have significant adverse effects on pumping capacity, contribute to irreversible tissue withdrawal, and weaken skeletal strength and stiffness of A. vastus. Within one month sponges exposed to warming (including combined treatment) ceased pumping (50–60%) and exhibited tissue withdrawal (10–25%). Thermal and acidification stress significantly reduced skeletal stiffness, and warming weakened it, potentially curtailing reef formation. Environmental data suggests conditions causing irreversible damage are possible in the field at +0.5 °C above current conditions, indicating that ongoing climate change is a serious and immediate threat to A. vastus, reef dependent communities, and potentially other glass sponges.
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Affiliation(s)
- A Stevenson
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, V6T 1Z4, Canada. .,Institute for the Oceans and Fisheries, University of British Columbia, Vancouver, British Columbia, Canada. .,Marine Evolutionary Ecology, GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105, Kiel, Germany.
| | - S K Archer
- Fisheries and Oceans Canada, Pacific Biological Station, 3190 Hammond Bay Road, Nanaimo, British Columbia, V9T 6N7, Canada.,Louisiana Universities Marine Consortium, 8124 Highway 56, Chauvin, Louisiana, 70344, USA
| | - J A Schultz
- Ocean Wise Research Institute, PO Box 3232, Vancouver, British Columbia, V6B3X8, Canada
| | - A Dunham
- Fisheries and Oceans Canada, Pacific Biological Station, 3190 Hammond Bay Road, Nanaimo, British Columbia, V9T 6N7, Canada
| | - J B Marliave
- Ocean Wise Research Institute, PO Box 3232, Vancouver, British Columbia, V6B3X8, Canada
| | - P Martone
- Department of Botany, University of British Columbia, Vancouver, British Columbia, V6T 1Z4, Canada
| | - C D G Harley
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, V6T 1Z4, Canada.,Institute for the Oceans and Fisheries, University of British Columbia, Vancouver, British Columbia, Canada
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7
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Wong E, Mölter J, Anggono V, Degnan SM, Degnan BM. Co-expression of synaptic genes in the sponge Amphimedon queenslandica uncovers ancient neural submodules. Sci Rep 2019; 9:15781. [PMID: 31673079 PMCID: PMC6823388 DOI: 10.1038/s41598-019-51282-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 09/28/2019] [Indexed: 12/13/2022] Open
Abstract
The synapse is a complex cellular module crucial to the functioning of neurons. It evolved largely through the exaptation of pre-existing smaller submodules, each of which are comprised of ancient sets of proteins that are conserved in modern animals and other eukaryotes. Although these ancient submodules themselves have non-neural roles, it has been hypothesized that they may mediate environmental sensing behaviors in aneural animals, such as sponges. Here we identify orthologues in the sponge Amphimedon queenslandica of genes encoding synaptic submodules in neural animals, and analyse their cell-type specific and developmental expression to determine their potential to be co-regulated. We find that genes comprising certain synaptic submodules, including those involved in vesicle trafficking, calcium-regulation and scaffolding of postsynaptic receptor clusters, are co-expressed in adult choanocytes and during metamorphosis. Although these submodules may contribute to sensory roles in this cell type and this life cycle stage, total synaptic gene co-expression profiles do not support the existence of a functional synapse in A. queenslandica. The lack of evidence for the co-regulation of genes necessary for pre- and post-synaptic functioning in A. queenslandica suggests that sponges, and perhaps the last common ancestor of sponges and other extant animals, had the ability to promulgate sensory inputs without complete synapse-like functionalities. The differential co-expression of multiple synaptic submodule genes in sponge choanocytes, which have sensory and feeding roles, however, is consistent with the metazoan ancestor minimally being able to undergo exo- and endocytosis in a controlled and localized manner.
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Affiliation(s)
- Eunice Wong
- School of Biological Sciences, University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Jan Mölter
- Queensland Brain Institute, University of Queensland, Brisbane, Queensland, 4072, Australia
- School of Mathematics and Physics, University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Victor Anggono
- Queensland Brain Institute, University of Queensland, Brisbane, Queensland, 4072, Australia
- Clem Jones Centre for Ageing Dementia Research, University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Sandie M Degnan
- School of Biological Sciences, University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Bernard M Degnan
- School of Biological Sciences, University of Queensland, Brisbane, Queensland, 4072, Australia.
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8
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Lavrov AI, Kosevich IA. Stolonial Movement: A New Type of Whole-Organism Behavior in Porifera. THE BIOLOGICAL BULLETIN 2018; 234:58-67. [PMID: 29694803 DOI: 10.1086/697113] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Sponges (phylum Porifera) traditionally are represented as inactive, sessile filter-feeding animals devoid of any behavior except filtering activity. However, different time-lapse techniques demonstrate that sponges are able to show a wide range of coordinated but slow whole-organism behavior. The present study concerns a peculiar type of such behavior in the psychrophilic demosponge Amphilectus lobatus: stolonial movement. During stolonial movement, sponges produce outgrowths (stolons) that crawl along a substrate with a speed of 4.4 ± 2.2 μm min-1 and branch, thus forming a complex net covering a considerable area of a substrate. This net is used by sponges to search for new points with appropriate environmental conditions for individual relocation. After such points are found, all cells of the parental sponge migrate through stolons, leaving a naked parental skeleton, forming one or several filial sponges in the new location. Thus, stolonial movement combines traits of crawling along the substrate and asexual reproduction. This behavior relies on massive cell dedifferentiation followed by coordinated cell migration to the point of new sponge body formation and their subsequent differentiation into specialized cell types.
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9
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Senatore A, Reese TS, Smith CL. Neuropeptidergic integration of behavior in Trichoplax adhaerens, an animal without synapses. J Exp Biol 2017; 220:3381-3390. [PMID: 28931721 PMCID: PMC5612019 DOI: 10.1242/jeb.162396] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 07/04/2017] [Indexed: 12/17/2022]
Abstract
Trichoplax adhaerens is a flat, millimeter-sized marine animal that adheres to surfaces and grazes on algae. Trichoplax displays a repertoire of different feeding behaviors despite the apparent absence of a true nervous system with electrical or chemical synapses. It glides along surfaces to find food, propelled by beating cilia on cells at its ventral surface, and pauses during feeding by arresting ciliary beating. We found that when endomorphin-like peptides are applied to an animal, ciliary beating is arrested, mimicking natural feeding pauses. Antibodies against these neuropeptides label cells that express the neurosecretory proteins and voltage-gated calcium channels implicated in regulated secretion. These cells are embedded in the ventral epithelium, where they comprise only 4% of the total, and are concentrated around the edge of the animal. Each bears a cilium likely to be chemosensory and used to detect algae. Trichoplax pausing during feeding or spontaneously in the absence of food often induce their neighbors to pause as well, even neighbors not in direct contact. Pausing behavior propagates from animal to animal across distances much greater than the signal that diffuses from just one animal, so we presume that the peptides secreted from one animal elicit secretion from nearby animals. Signal amplification by peptide-induced peptide secretion explains how a small number of sensory secretory cells lacking processes and synapses can evoke a wave of peptide secretion across the entire animal to globally arrest ciliary beating and allow pausing during feeding.
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Affiliation(s)
- Adriano Senatore
- University of Toronto Mississauga, Mississauga, ON, Canada L5L 1C6
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10
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Pineda MC, Strehlow B, Kamp J, Duckworth A, Jones R, Webster NS. Effects of combined dredging-related stressors on sponges: a laboratory approach using realistic scenarios. Sci Rep 2017; 7:5155. [PMID: 28701759 PMCID: PMC5507900 DOI: 10.1038/s41598-017-05251-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 05/31/2017] [Indexed: 01/26/2023] Open
Abstract
Dredging can cause increased suspended sediment concentrations (SSCs), light attenuation and sedimentation in marine communities. In order to determine the combined effects of dredging-related pressures on adult sponges, three species spanning different nutritional modes and morphologies were exposed to 5 treatment levels representing realistic dredging scenarios. Most sponges survived under low to moderate turbidity scenarios (SSCs of ≤ 33 mg L−1, and a daily light integral of ≥0.5 mol photons m−2 d−1) for up to 28 d. However, under the highest turbidity scenario (76 mg L−1, 0.1 mol photons m−2 d−1) there was 20% and 90% mortality of the phototrophic sponges Cliona orientalis and Carteriospongia foliascens respectively, and tissue regression in the heterotrophic Ianthella basta. All three sponge species exhibited mechanisms to effectively tolerate dredging-related pressures in the short term (e.g. oscula closure, mucus production and tissue regression), although reduced lipids and deterioration of sponge health suggest that longer term exposure to similar conditions is likely to result in higher mortality. These results suggest that the combination of high SSCs and low light availability can accelerate mortality, increasing the probability of biological effects, although there is considerable interspecies variability in how adult sponges respond to dredging pressures.
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Affiliation(s)
- Mari-Carmen Pineda
- Australian Institute of Marine Science (AIMS), Townsville, QLD and Perth, WA, Australia. .,Western Australian Marine Science Institution, Perth, WA, Australia.
| | - Brian Strehlow
- Australian Institute of Marine Science (AIMS), Townsville, QLD and Perth, WA, Australia.,Western Australian Marine Science Institution, Perth, WA, Australia.,School of Biological Sciences, Centre for Microscopy Characterisation and Analysis, and Oceans Institute, University of Western Australia, Crawley, WA, Australia
| | - Jasmine Kamp
- James Cook University, Townsville, QLD, Australia
| | - Alan Duckworth
- Australian Institute of Marine Science (AIMS), Townsville, QLD and Perth, WA, Australia.,Western Australian Marine Science Institution, Perth, WA, Australia
| | - Ross Jones
- Australian Institute of Marine Science (AIMS), Townsville, QLD and Perth, WA, Australia.,Western Australian Marine Science Institution, Perth, WA, Australia
| | - Nicole S Webster
- Australian Institute of Marine Science (AIMS), Townsville, QLD and Perth, WA, Australia.,Western Australian Marine Science Institution, Perth, WA, Australia
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11
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Brown RR, Davis CS, Leys SP. Clones or clans: the genetic structure of a deep-sea sponge,Aphrocallistes vastus,in unique sponge reefs of British Columbia, Canada. Mol Ecol 2017; 26:1045-1059. [DOI: 10.1111/mec.13982] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 11/21/2016] [Accepted: 11/28/2016] [Indexed: 11/28/2022]
Affiliation(s)
- Rachel R. Brown
- Department of Biological Sciences; University of Alberta; CW 422 Biological Sciences Building Edmonton Alberta Canada T6G 2E9
| | - Corey S. Davis
- Department of Biological Sciences; University of Alberta; CW 422 Biological Sciences Building Edmonton Alberta Canada T6G 2E9
| | - Sally P. Leys
- Department of Biological Sciences; University of Alberta; CW 422 Biological Sciences Building Edmonton Alberta Canada T6G 2E9
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12
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Strehlow BW, Jorgensen D, Webster NS, Pineda MC, Duckworth A. Using a thermistor flowmeter with attached video camera for monitoring sponge excurrent speed and oscular behaviour. PeerJ 2016; 4:e2761. [PMID: 27994973 PMCID: PMC5157188 DOI: 10.7717/peerj.2761] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 11/05/2016] [Indexed: 12/28/2022] Open
Abstract
A digital, four-channel thermistor flowmeter integrated with time-lapse cameras was developed as an experimental tool for measuring pumping rates in marine sponges, particularly those with small excurrent openings (oscula). Combining flowmeters with time-lapse imagery yielded valuable insights into the contractile behaviour of oscula in Cliona orientalis. Osculum cross-sectional area (OSA) was positively correlated to measured excurrent speeds (ES), indicating that sponge pumping and osculum contraction are coordinated behaviours. Both OSA and ES were positively correlated to pumping rate (Q). Diel trends in pumping activity and osculum contraction were also observed, with sponges increasing their pumping activity to peak at midday and decreasing pumping and contracting oscula at night. Short-term elevation of the suspended sediment concentration (SSC) within the seawater initially decreased pumping rates by up to 90%, ultimately resulting in closure of the oscula and cessation of pumping.
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Affiliation(s)
- Brian W Strehlow
- Centre for Microscopy, Characterisation and Analysis, School of Plant Biology, and Oceans Institute, University of Western Australia, Crawley, WA, Australia; Western Australian Marine Science Institution, Crawley, WA, Australia; Australian Institute of Marine Science, Townsville, QLD, Australia
| | - Damien Jorgensen
- Australian Institute of Marine Science , Townsville , QLD , Australia
| | - Nicole S Webster
- Western Australian Marine Science Institution, Crawley, WA, Australia; Australian Institute of Marine Science, Townsville, QLD, Australia
| | - Mari-Carmen Pineda
- Western Australian Marine Science Institution, Crawley, WA, Australia; Australian Institute of Marine Science, Townsville, QLD, Australia
| | - Alan Duckworth
- Western Australian Marine Science Institution, Crawley, WA, Australia; Australian Institute of Marine Science, Townsville, QLD, Australia
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13
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Ueda N, Richards GS, Degnan BM, Kranz A, Adamska M, Croll RP, Degnan SM. An ancient role for nitric oxide in regulating the animal pelagobenthic life cycle: evidence from a marine sponge. Sci Rep 2016; 6:37546. [PMID: 27874071 PMCID: PMC5118744 DOI: 10.1038/srep37546] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 11/01/2016] [Indexed: 01/08/2023] Open
Abstract
In many marine invertebrates, larval metamorphosis is induced by environmental cues that activate sensory receptors and signalling pathways. Nitric oxide (NO) is a gaseous signalling molecule that regulates metamorphosis in diverse bilaterians. In most cases NO inhibits or represses this process, although it functions as an activator in some species. Here we demonstrate that NO positively regulates metamorphosis in the poriferan Amphimedon queenslandica. High rates of A. queenslandica metamorphosis normally induced by a coralline alga are inhibited by an inhibitor of nitric oxide synthase (NOS) and by a NO scavenger. Consistent with this, an artificial donor of NO induces metamorphosis even in the absence of the alga. Inhibition of the ERK signalling pathway prevents metamorphosis in concert with, or downstream of, NO signalling; a NO donor cannot override the ERK inhibitor. NOS gene expression is activated late in embryogenesis and in larvae, and is enriched in specific epithelial and subepithelial cell types, including a putative sensory cell, the globular cell; DAF-FM staining supports these cells being primary sources of NO. Together, these results are consistent with NO playing an activating role in induction of A. queenslandica metamorphosis, evidence of its highly conserved regulatory role in metamorphosis throughout the Metazoa.
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Affiliation(s)
- Nobuo Ueda
- School of Biological Sciences, University of Queensland, Brisbane QLD 4072, Australia
| | - Gemma S. Richards
- School of Biological Sciences, University of Queensland, Brisbane QLD 4072, Australia
| | - Bernard M. Degnan
- School of Biological Sciences, University of Queensland, Brisbane QLD 4072, Australia
| | - Alexandrea Kranz
- School of Biological Sciences, University of Queensland, Brisbane QLD 4072, Australia
| | - Maja Adamska
- School of Biological Sciences, University of Queensland, Brisbane QLD 4072, Australia
| | - Roger P. Croll
- Department of Physiology & Biophysics, Dalhousie University, Halifax NS B3H 4R2, Canada
| | - Sandie M. Degnan
- School of Biological Sciences, University of Queensland, Brisbane QLD 4072, Australia
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14
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Senatore A, Raiss H, Le P. Physiology and Evolution of Voltage-Gated Calcium Channels in Early Diverging Animal Phyla: Cnidaria, Placozoa, Porifera and Ctenophora. Front Physiol 2016; 7:481. [PMID: 27867359 PMCID: PMC5095125 DOI: 10.3389/fphys.2016.00481] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 10/07/2016] [Indexed: 12/18/2022] Open
Abstract
Voltage-gated calcium (Cav) channels serve dual roles in the cell, where they can both depolarize the membrane potential for electrical excitability, and activate transient cytoplasmic Ca2+ signals. In animals, Cav channels play crucial roles including driving muscle contraction (excitation-contraction coupling), gene expression (excitation-transcription coupling), pre-synaptic and neuroendocrine exocytosis (excitation-secretion coupling), regulation of flagellar/ciliary beating, and regulation of cellular excitability, either directly or through modulation of other Ca2+-sensitive ion channels. In recent years, genome sequencing has provided significant insights into the molecular evolution of Cav channels. Furthermore, expanded gene datasets have permitted improved inference of the species phylogeny at the base of Metazoa, providing clearer insights into the evolution of complex animal traits which involve Cav channels, including the nervous system. For the various types of metazoan Cav channels, key properties that determine their cellular contribution include: Ion selectivity, pore gating, and, importantly, cytoplasmic protein-protein interactions that direct sub-cellular localization and functional complexing. It is unclear when these defining features, many of which are essential for nervous system function, evolved. In this review, we highlight some experimental observations that implicate Cav channels in the physiology and behavior of the most early-diverging animals from the phyla Cnidaria, Placozoa, Porifera, and Ctenophora. Given our limited understanding of the molecular biology of Cav channels in these basal animal lineages, we infer insights from better-studied vertebrate and invertebrate animals. We also highlight some apparently conserved cellular functions of Cav channels, which might have emerged very early on during metazoan evolution, or perhaps predated it.
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Affiliation(s)
- Adriano Senatore
- Department of Biology, University of Toronto Mississauga Mississauga, ON, Canada
| | - Hamad Raiss
- Department of Biology, University of Toronto Mississauga Mississauga, ON, Canada
| | - Phuong Le
- Department of Biology, University of Toronto Mississauga Mississauga, ON, Canada
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15
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Ryan JF, Chiodin M. Where is my mind? How sponges and placozoans may have lost neural cell types. Philos Trans R Soc Lond B Biol Sci 2015; 370:20150059. [PMID: 26554046 PMCID: PMC4650130 DOI: 10.1098/rstb.2015.0059] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/12/2015] [Indexed: 01/01/2023] Open
Abstract
Recent phylogenomic evidence suggests that ctenophores may be the sister group to the rest of animals. This phylogenetic arrangement opens the possibility that sponges and placozoans could have lost neural cell types or that the ctenophore nervous system evolved independently. We critically review evidence to date that has been put forth in support of independent evolution of neural cell types in ctenophores. We observe a reluctance in the literature to consider a lost nervous system in sponges and placozoans and suggest that this may be due to historical bias and the commonly misconstrued concept of animal complexity. In support of the idea of loss (or modification beyond recognition), we provide hypothetical scenarios to show how sponges and placozoans may have benefitted from the loss and/or modification of their neural cell types.
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Affiliation(s)
- Joseph F Ryan
- Whitney Laboratory for Marine Bioscience, University of Florida, 9505 Ocean Shore Blvd, St Augustine, FL 32080, USA Department of Biology, University of Florida, Gainesville, FL 32611, USA
| | - Marta Chiodin
- Whitney Laboratory for Marine Bioscience, University of Florida, 9505 Ocean Shore Blvd, St Augustine, FL 32080, USA Department of Biology, University of Florida, Gainesville, FL 32611, USA
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16
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Meech RW. Electrogenesis in the lower Metazoa and implications for neuronal integration. ACTA ACUST UNITED AC 2015; 218:537-50. [PMID: 25696817 DOI: 10.1242/jeb.111955] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Electrogenic communication appears to have evolved independently in a variety of animal and plant lineages. Considered here are metazoan cells as disparate as the loose three-dimensional parenchyma of glass sponges, the two-dimensional epithelial sheets of hydrozoan jellyfish and the egg cell membranes of the ctenophore Beroe ovata, all of which are capable of generating electrical impulses. Neuronal electrogenesis may have evolved independently in ctenophores and cnidarians but the dearth of electrophysiological data relating to ctenophore nerves means that our attention is focused on the Cnidaria, whose nervous systems have been the subject of extensive study. The aim here is to show how their active and passive neuronal properties interact to give integrated behaviour. Neuronal electrogenesis, goes beyond simply relaying 'states of excitement' and utilizes the equivalent of a set of basic electrical 'apps' to integrate incoming sensory information with internally generated pacemaker activity. A small number of membrane-based processes make up these analogue applications. Passive components include the decremental spread of current determined by cellular anatomy; active components include ion channels specified by their selectivity and voltage dependence. A recurring theme is the role of inactivating potassium channels in regulating performance. Although different aspects of cnidarian behaviour are controlled by separate neuronal systems, integrated responses and coordinated movements depend on interactions between them. Integrative interactions discussed here include those between feeding and swimming, between tentacle contraction and swimming and between slow and fast swimming in the hydrozoan jellyfish Aglantha digitale.
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Affiliation(s)
- Robert W Meech
- School of Physiology and Pharmacology, University of Bristol, Bristol BS8 1TD, UK
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17
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Abstract
Genomic and transcriptomic analyses show that sponges possess a large repertoire of genes associated with neuronal processes in other animals, but what is the evidence these are used in a coordination or sensory context in sponges? The very different phylogenetic hypotheses under discussion today suggest very different scenarios for the evolution of tissues and coordination systems in early animals. The sponge genomic 'toolkit' either reflects a simple, pre-neural system used to protect the sponge filter or represents the remnants of a more complex signalling system and sponges have lost cell types, tissues and regionalization to suit their current suspension-feeding habit. Comparative transcriptome data can be informative but need to be assessed in the context of knowledge of sponge tissue structure and physiology. Here, I examine the elements of the sponge neural toolkit including sensory cells, conduction pathways, signalling molecules and the ionic basis of signalling. The elements described do not fit the scheme of a loss of sophistication, but seem rather to reflect an early specialization for suspension feeding, which fits with the presumed ecological framework in which the first animals evolved.
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Affiliation(s)
- Sally P Leys
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
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18
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Stubler AD, Duckworth AR, Peterson BJ. The effects of coastal development on sponge abundance, diversity, and community composition on Jamaican coral reefs. MARINE POLLUTION BULLETIN 2015; 96:261-270. [PMID: 25979812 DOI: 10.1016/j.marpolbul.2015.05.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Revised: 04/25/2015] [Accepted: 05/04/2015] [Indexed: 06/04/2023]
Abstract
Over the past decade, development along the northern coast of Jamaica has accelerated, resulting in elevated levels of sedimentation on adjacent reefs. To understand the effects of this development on sponge community dynamics, we conducted surveys at three locations with varying degrees of adjacent coastal development to quantify species richness, abundance and diversity at two depths (8-10 m and 15-18 m). Sediment accumulation rate, total suspended solids and other water quality parameters were also quantified. The sponge community at the location with the least coastal development and anthropogenic influence was often significantly different from the other two locations, and exhibited higher sponge abundance, richness, and diversity. Sponge community composition and size distribution were statistically different among locations. This study provides correlative evidence that coastal development affects aspects of sponge community ecology, although the precise mechanisms are still unclear.
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Affiliation(s)
- Amber D Stubler
- Stony Brook University, School of Marine and Atmospheric Sciences, 239 Montauk Highway, Southampton, NY 11968, United States.
| | - Alan R Duckworth
- Australia Institute of Marine Science (AIMS), PMB 3 Townsville MC, Townsville 4810, Queensland, Australia.
| | - Bradley J Peterson
- Stony Brook University, School of Marine and Atmospheric Sciences, 239 Montauk Highway, Southampton, NY 11968, United States.
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19
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The hidden biology of sponges and ctenophores. Trends Ecol Evol 2015; 30:282-91. [DOI: 10.1016/j.tree.2015.03.003] [Citation(s) in RCA: 129] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2014] [Revised: 02/27/2015] [Accepted: 03/02/2015] [Indexed: 12/21/2022]
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20
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Nakanishi N, Stoupin D, Degnan SM, Degnan BM. Sensory Flask Cells in Sponge Larvae Regulate Metamorphosis via Calcium Signaling. Integr Comp Biol 2015; 55:1018-27. [PMID: 25898842 DOI: 10.1093/icb/icv014] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The Porifera (sponges) is one of the earliest phyletic lineages to branch off the metazoan tree. Although the body-plan of sponges is among the simplest in the animal kingdom and sponges lack nervous systems that communicate environmental signals to other cells, their larvae have sensory systems that generate coordinated responses to environmental cues. In eumetazoans (Cnidaria and Bilateria), the nervous systems of larvae often regulate metamorphosis through Ca(2+)-dependent signal transduction. In sponges, neither the identity of the receptor system that detects an inductive environmental cue (hereafter "metamorphic cues") nor the signaling system that mediates settlement and metamorphosis are known. Using a combination of behavioral assays and surgical manipulations, we show here that specialized epithelial cells-referred to as flask cells-enriched in the anterior third of the Amphimedon queenslandica larva are most likely to be the sensory cells that detect the metamorphic cues. Surgical removal of the region enriched in flask cells in a larva inhibits the initiation of metamorphosis. The flask cell has an apical sensory apparatus with a cilium surrounded by an apical F-actin-rich protrusion, and numerous vesicles, hallmarks of eumetazoan sensory-neurosecretory cells. We demonstrate that these flask cells respond to metamorphic cues by elevating intracellular Ca(2+) levels, and that this elevation is necessary for the initiation of metamorphosis. Taken together, these analyses suggest that sponge larvae have sensory-secretory epithelial cells capable of converting exogenous cues into internal signals via Ca(2+)-mediated signaling, which is necessary for the initiation of metamorphosis. Similarities in the morphology, physiology, and function of the sensory flask cells in sponge larvae with the sensory/neurosecretory cells in eumetazoan larvae suggest this sensory system predates the divergence of Porifera and Eumetazoa.
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Affiliation(s)
- Nagayasu Nakanishi
- School of Biological Sciences, University of Queensland, Brisbane QLD 4072, Australia
| | - Daniel Stoupin
- School of Biological Sciences, University of Queensland, Brisbane QLD 4072, Australia
| | - Sandie M Degnan
- School of Biological Sciences, University of Queensland, Brisbane QLD 4072, Australia
| | - Bernard M Degnan
- School of Biological Sciences, University of Queensland, Brisbane QLD 4072, Australia
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21
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Ecological constraints on the origin of neurones. J Math Biol 2015; 71:1299-324. [DOI: 10.1007/s00285-015-0862-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 01/14/2015] [Indexed: 12/20/2022]
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22
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Monk T, Paulin MG. Predation and the origin of neurones. BRAIN, BEHAVIOR AND EVOLUTION 2014; 84:246-61. [PMID: 25472692 DOI: 10.1159/000368177] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Accepted: 04/24/2014] [Indexed: 11/19/2022]
Abstract
The core design of spiking neurones is remarkably similar throughout the animal kingdom. Their basic function as fast-signalling thresholding cells might have been established very early in their evolutionary history. Identifying the selection pressures that drove animals to evolve spiking neurones could help us interpret their design and function today. We review fossil, ecological and molecular evidence to investigate when and why animals evolved spiking neurones. Fossils suggest that animals evolved nervous systems soon after the advent of animal-on-animal predation, 550 million years ago (MYa). Between 550 and 525 MYa, we see the first fossil appearances of many animal innovations, including eyes. Animal behavioural complexity increased during this period as well, as evidenced by their traces, suggesting that nervous systems were an innovation of that time. Fossils further suggest that, before 550 MYa, animals were either filter feeders or microbial mat grazers. Extant sponges and Trichoplax perform these tasks using energetically cheaper alternatives than spiking neurones. Genetic evidence testifies that nervous systems evolved before the protostome-deuterostome split. It is less clear whether nervous systems evolved before the cnidarian-bilaterian split, so cnidarians and bilaterians might have evolved their nervous systems independently. The fossil record indicates that the advent of predation could fit into the window of time between those two splits, though molecular clock studies dispute this claim. Collectively, these lines of evidence indicate that animals evolved spiking neurones soon after they started eating each other. The first sensory neurones could have been threshold detectors that spiked in response to other animals in their proximity, alerting them to perform precisely timed actions, such as striking or fleeing.
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Affiliation(s)
- Travis Monk
- Department of Zoology, University of Otago, Dunedin, New Zealand
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23
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Hammel JU, Nickel M. A new flow-regulating cell type in the Demosponge Tethya wilhelma - functional cellular anatomy of a leuconoid canal system. PLoS One 2014; 9:e113153. [PMID: 25409176 PMCID: PMC4237394 DOI: 10.1371/journal.pone.0113153] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 10/20/2014] [Indexed: 12/25/2022] Open
Abstract
Demosponges possess a leucon-type canal system which is characterized by a highly complex network of canal segments and choanocyte chambers. As sponges are sessile filter feeders, their aquiferous system plays an essential role in various fundamental physiological processes. Due to the morphological and architectural complexity of the canal system and the strong interdependence between flow conditions and anatomy, our understanding of fluid dynamics throughout leuconoid systems is patchy. This paper provides comprehensive morphometric data on the general architecture of the canal system, flow measurements and detailed cellular anatomical information to help fill in the gaps. We focus on the functional cellular anatomy of the aquiferous system and discuss all relevant cell types in the context of hydrodynamic and evolutionary constraints. Our analysis is based on the canal system of the tropical demosponge Tethya wilhelma, which we studied using scanning electron microscopy. We found a hitherto undescribed cell type, the reticuloapopylocyte, which is involved in flow regulation in the choanocyte chambers. It has a highly fenestrated, grid-like morphology and covers the apopylar opening. The minute opening of the reticuloapopylocyte occurs in an opened, intermediate and closed state. These states permit a gradual regulation of the total apopylar opening area. In this paper the three states are included in a theoretical study into flow conditions which aims to draw a link between functional cellular anatomy, the hydrodynamic situation and the regular body contractions seen in T. wilhelma. This provides a basis for new hypotheses regarding the function of bypass elements and the role of hydrostatic pressure in body contractions. Our study provides insights into the local and global flow conditions in the sponge canal system and thus enhances current understanding of related physiological processes.
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Affiliation(s)
- Jörg U. Hammel
- Institut für Spezielle Zoologie und Evolutionsbiologie mit Phyletischem Museum, Friedrich-Schiller-Universität Jena, Erbertstr. 1, 07743, Jena, Germany
| | - Michael Nickel
- Institut für Spezielle Zoologie und Evolutionsbiologie mit Phyletischem Museum, Friedrich-Schiller-Universität Jena, Erbertstr. 1, 07743, Jena, Germany
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24
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Milinkeviciute G, Gentile C, Neely GG. Drosophila as a tool for studying the conserved genetics of pain. Clin Genet 2012; 82:359-66. [PMID: 22880632 DOI: 10.1111/j.1399-0004.2012.01941.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Revised: 07/23/2012] [Accepted: 07/23/2012] [Indexed: 11/27/2022]
Abstract
Survival of all animals depends on an accurate representation of the world, and an organism must be capable of prioritizing and responding to potentially hazardous conditions. This ability is dependent on nociception, the sensory process allowing animals to detect and avoid potentially harmful stimuli. Nociception is the sensory process that results in the subjective experience of 'pain' in humans. Because of its vital and broad role in animal biology, pain/nociception is a complex, whole-body physiological process that is under stringent evolutionary pressure. Here, we discuss the utility of Drosophila melanogaster as an emerging model organism for studying the conserved genetics of nociception, particularly with respect to recently developed high-throughput Drosophila 'pain' paradigms.
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Affiliation(s)
- G Milinkeviciute
- Neuroscience Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
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25
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Conaco C, Neveu P, Zhou H, Arcila ML, Degnan SM, Degnan BM, Kosik KS. Transcriptome profiling of the demosponge Amphimedon queenslandica reveals genome-wide events that accompany major life cycle transitions. BMC Genomics 2012; 13:209. [PMID: 22646746 PMCID: PMC3447736 DOI: 10.1186/1471-2164-13-209] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Accepted: 04/02/2012] [Indexed: 11/22/2022] Open
Abstract
Background The biphasic life cycle with pelagic larva and benthic adult stages is widely observed in the animal kingdom, including the Porifera (sponges), which are the earliest branching metazoans. The demosponge, Amphimedon queenslandica, undergoes metamorphosis from a free-swimming larva into a sessile adult that bears no morphological resemblance to other animals. While the genome of A. queenslandica contains an extensive repertoire of genes very similar to that of complex bilaterians, it is as yet unclear how this is drawn upon to coordinate changing morphological features and ecological demands throughout the sponge life cycle. Results To identify genome-wide events that accompany the pelagobenthic transition in A. queenslandica, we compared global gene expression profiles at four key developmental stages by sequencing the poly(A) transcriptome using SOLiD technology. Large-scale changes in transcription were observed as sponge larvae settled on the benthos and began metamorphosis. Although previous systematics suggest that the only clear homology between Porifera and other animals is in the embryonic and larval stages, we observed extensive use of genes involved in metazoan-associated cellular processes throughout the sponge life cycle. Sponge-specific transcripts are not over-represented in the morphologically distinct adult; rather, many genes that encode typical metazoan features, such as cell adhesion and immunity, are upregulated. Our analysis further revealed gene families with candidate roles in competence, settlement, and metamorphosis in the sponge, including transcription factors, G-protein coupled receptors and other signaling molecules. Conclusions This first genome-wide study of the developmental transcriptome in an early branching metazoan highlights major transcriptional events that accompany the pelagobenthic transition and point to a network of regulatory mechanisms that coordinate changes in morphology with shifting environmental demands. Metazoan developmental and structural gene orthologs are well-integrated into the expression profiles at every stage of sponge development, including the adult. The utilization of genes involved in metazoan-associated processes throughout sponge development emphasizes the potential of the genome of the last common ancestor of animals to generate phenotypic complexity.
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Affiliation(s)
- Cecilia Conaco
- Neuroscience Research Institute and Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA 93106, USA
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26
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Abstract
Sponges have become the focus of studies on molecular evolution and the evolution of animal body plans due to their ancient branching point in the metazoan lineage. Whereas our former understanding of sponge function was largely based on a morphological perspective, the recent availability of the first full genome of a sponge (Amphimedon queenslandica), and of the transcriptomes of other sponges, provides a new way of understanding sponges by their molecular components. This wealth of genetic information not only confirms some long-held ideas about sponge form and function but also poses new puzzles. For example, the Amphimedon sponge genome tells us that sponges possess a repertoire of genes involved in control of cell proliferation and in regulation of development. In vitro expression studies with genes involved in stem cell maintenance confirm that archaeocytes are the main stem cell population and are able to differentiate into many cell types in the sponge including pinacocytes and choanocytes. Therefore, the diverse roles of archaeocytes imply differential gene expression within a single cell ontogenetically, and gene expression is likely also different in different species; but what triggers cells to enter one pathway and not another and how each archaeocyte cell type can be identified based on this gene knowledge are new challenges. Whereas molecular data provide a powerful new tool for interpreting sponge form and function, because sponges are suspension feeders, their body plan and physiology are very much dependent on their physical environment, and in particular on flow. Therefore, in order to integrate new knowledge of molecular data into a better understanding the sponge body plan, it is important to use an organismal approach. In this chapter, we give an account of sponge body organization as it relates to the physiology of the sponge in light of new molecular data. We focus, in particular, on the structure of sponge tissues and review descriptive as well as experimental work on choanocyte morphology and function. Special attention is given to pinacocyte epithelia, cell junctions, and the molecules present in sponge epithelia. Studies describing the role of the pinacoderm in sensing, coordination, and secretion are reviewed. A wealth of recent work describes gene presence and expression patterns in sponge tissues during development, and we review this in the context of the previous descriptions of sponge morphology and physiology. A final section addresses recent findings of genes involved in the immune response. This review is far from exhaustive but intends rather to revisit for non-specialists key aspects of sponge morphology and physiology in light of new molecular data as a means to better understand and interpret sponge form and function today.
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Affiliation(s)
- Sally P Leys
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
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27
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Renard E, Vacelet J, Gazave E, Lapébie P, Borchiellini C, Ereskovsky AV. Origin of the neuro-sensory system: new and expected insights from sponges. Integr Zool 2011; 4:294-308. [PMID: 21392302 DOI: 10.1111/j.1749-4877.2009.00167.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The capacity of all cells to respond to stimuli implies the conduction of information at least over short distances. In multicellular organisms, more complex systems of integration and coordination of activities are necessary. In most animals, the processing of information is performed by a nervous system. Among the most basal taxa, sponges are nerveless so that it is traditionally assumed that the integrated neuro-sensory system originated only once in Eumetazoa, a hypothesis not in agreement with some recent phylogenomic studies. The aim of this review is to show that recent data on sponges might provide clues for understanding the origin of this complex system. First, sponges are able to react to external stimuli, and some of them display spontaneous movement activities. These coordinated behaviors involve nervous system-like mechanisms, such as action potentials and/or neurotransmitters. Second, genomic analyses show that sponges possess genes orthologous to those involved in the patterning or functioning of the neuro-sensory system in Eumetazoa. Finally, some of these genes are expressed in specific cells (flask cells, choanocytes). Together with ultrastructural data, this gives rise to challenging hypotheses concerning cell types that might play neuro-sensory-like roles in sponges.
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Affiliation(s)
- Emmanuelle Renard
- Centre d'océanologie de Marseille, CNRS - Aix-Marseille Université, Marseille, France.
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Ramoino P, Ledda FD, Ferrando S, Gallus L, Bianchini P, Diaspro A, Fato M, Tagliafierro G, Manconi R. Metabotropic γ-aminobutyric acid (GABAB) receptors modulate feeding behavior in the calcisponge Leucandra aspera. ACTA ACUST UNITED AC 2010; 315:132-40. [PMID: 21370481 DOI: 10.1002/jez.657] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2010] [Revised: 10/12/2010] [Accepted: 11/03/2010] [Indexed: 11/07/2022]
Abstract
Here, we report the presence of the γ-aminobutyric acid (GABA)-ergic system in the calcisponge Leucandra aspera and examine the cellular localization of the components of this system, including GABA-like receptors using immunofluorescence and confocal microscopy. Furthermore, we demonstrate for the first time that GABA plays a functional role as a messenger in regulating sponge-feeding behavior. We found that both GABA(B) R1 and R2 subunits are present in the choanocytes of sponges as well as in the eso- and endopinacocytes. The functional role of GABA in the feeding behavior of this sponge was tested. The involvement of GABA receptors in the endocytic processes in L. aspera was demonstrated with dextran conjugated to Texas Red as a marker for material ingestion and by treating isolated sponge cells with a GABA(B) receptor agonist and an antagonist. The amount of dextran that was ingested increased in dissociated sponge cells when the GABA(B) receptor agonist baclofen was used, and this stimulatory effect was prevented by treatment with the GABA(B) receptor antagonist phaclofen. The baclofen effect on uptake was blocked by treatment with pertussis toxin, thus indicating a role for G proteins in modulating feeding behavior in L. aspera. Moreover, we found evidence that GABA receptors are involved in the consumption of dissolved organic matter by sponge cells. These findings suggest that GABA receptors and their functional role are highly conservative traits in the animal kingdom prenervous system evolution.
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Affiliation(s)
- Paola Ramoino
- Dipartimento per lo Studio del Territorio e delle sue Risorse (DIPTERIS), Università di Genova, Genova, Italy.
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Elliott GRD, Leys SP. Evidence for glutamate, GABA and NO in coordinating behaviour in the sponge, Ephydatia muelleri (Demospongiae, Spongillidae). ACTA ACUST UNITED AC 2010; 213:2310-21. [PMID: 20543130 DOI: 10.1242/jeb.039859] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The view that sponges lack tissue level organisation, epithelia, sensory cells and coordinated behaviour is challenged by recent molecular studies showing the existence in Porifera of molecules and proteins that define cell signalling systems in higher order metazoans. Demonstration that freshwater sponges can contract their canals in an organised manner in response to both external and endogenous stimuli prompted us to examine the physiology of the contraction behaviour. Using a combination of digital time-lapse microscopy, high-performance liquid chromatography-mass spectrometry (HPLC-MS) analysis, immunocytochemistry and pharmacological manipulations, we tested the role of the diffusible amino acids glutamate and gamma-aminobutyric acid (GABA) and a short-lived diffusible gas, nitric oxide (NO), in triggering or modulating contractions in Ephydatia muelleri. We identified pools of glutamate, glutamine and GABA used to maintain a metabotropic glutamate and GABA receptor signalling system. Glutamate induced contractions and propagation of a stereotypical behaviour inflating and deflating the canal system, acting in a dose-dependent manner. Glutamate-triggered contractions were blocked by the metabatropic glutamate receptor inhibitor AP3 and by incubation of the sponge in an allosteric competitive inhibitor of glutamate, Kynurenic acid. Incubation in GABA inhibited glutamate-triggered contractions of the sponge. Nitric oxide synthase, involved in the formation of the diffusible gas NO, was localised using NADPH-diaphorase to mesenchyme cells in the osculum and pinacoderm. A cGMP assay showed the same cells were labelled suggesting that the NO system is functional. Our findings suggest sponges coordinate behaviour using chemical messenger systems common to other animals.
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Affiliation(s)
- Glen R D Elliott
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada, T6G 2E9
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Müller WEG, Wang X, Schröder HC, Korzhev M, Grebenjuk VA, Markl JS, Jochum KP, Pisignano D, Wiens M. A cryptochrome-based photosensory system in the siliceous sponge Suberites domuncula (Demospongiae). FEBS J 2010; 277:1182-201. [DOI: 10.1111/j.1742-4658.2009.07552.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Björn LO, Rasmusson AG. Photosensitivity in sponge due to cytochrome c oxidase? Photochem Photobiol Sci 2009; 8:755-7. [PMID: 19492101 DOI: 10.1039/b904988f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An action spectrum for photosensitivity in sponge larvae published by Leys et al. [J. Comp. Physiol., A, 2002, 188, 199-202] was interpreted by the authors as being due to a combination of light absorption by flavin or carotenoid in the blue region, and another pigment such as pterin in the long-wavelength region. Here we show here that their action spectrum closely matches the absorption spectrum of reduced cytochrome c oxidase that is present in sponges, and compare with other photoreactions which are thought to be due to this chromoprotein.
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Affiliation(s)
- Lars Olof Björn
- Department of Cell and Organism Biology, Lund University, 223 62 Lund, Sweden.
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Gazave E, Lapébie P, Renard E, Bézac C, Boury-Esnault N, Vacelet J, Pérez T, Manuel M, Borchiellini C. NK homeobox genes with choanocyte-specific expression in homoscleromorph sponges. Dev Genes Evol 2008; 218:479-89. [PMID: 18704494 DOI: 10.1007/s00427-008-0242-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2008] [Accepted: 07/22/2008] [Indexed: 01/16/2024]
Abstract
Data on nonbilaterian animals (sponges, cnidarians, and ctenophores) have suggested that Antennapedia (ANTP) class homeobox genes played a crucial role in the early diversification of animal body plans. Estimates of ancestral gene diversity within this important class of developmental regulators have been mostly based on recent analyses of the complete genome of a demosponge species, leading to the proposal that all ANTP families found in nonsponges animals (eumetazoans) derived from an ancestral "proto-NK" six-gene cluster. However, a single sponge species cannot reveal ancestral metazoan traits, in particular because lineage-specific gene duplications or losses are likely to have occurred during the long history of the Porifera. We thus looked for ANTP genes by degenerate polymerase chain reaction search in five species belonging to the Homoscleromorpha, a sponge lineage recently phylogenetically classified outside demosponges and characterized by unique histological features. We identified new genes of the ANTP class called HomoNK. Our phylogenetic analyses placed HomoNK (without significant support) close to the NK6 and NK7 families of cnidarian and bilaterian ANTP genes and did not recover the monophyly of the proposed "proto-NK" cluster. Our expression analyses of the HomoNK gene OlobNK in adult Oscarella lobularis showed that this gene is a strict marker of choanocytes, the most typical sponge cell type characterized by an apical flagellum surrounded by a collar of microvilli. These results are discussed in the light of the predominant neurosensory expression of NK6 and NK7 genes in bilaterians and of the recent proposal that choanocytes could be the sponge homologs of sensory cells.
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Affiliation(s)
- Eve Gazave
- Centre d'Océanologie de Marseille, Aix-Marseille Université, CNRS-UMR 6540, Station marine d'Endoume, rue de la batterie des Lions, 13007, Marseille, France
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Riesgo A, Taylor C, Leys SP. Reproduction in a carnivorous sponge: the significance of the absence of an aquiferous system to the sponge body plan. Evol Dev 2008; 9:618-31. [PMID: 17976057 DOI: 10.1111/j.1525-142x.2007.00200.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Sponges usually produce, release, and capture gametes via the aquiferous system, and so the absence of both choanocytes and an aquiferous system in the carnivorous sponge Asbestopluma occidentalis has led to unusual characteristics of development for this Phylum. Sperm are highly specialized elongate cells tightly packed into spermatic cysts in the peripheral tissue of the sponge. Mature spermatozoa have proacrosomal vesicles at the anterior end and a ciliary pit surrounding the flagellum. Clusters of four to five oocytes are in synchronous stages of cleavage, suggesting that fertilization is synchronous. All stages of embryos occur in the same individual. Early cleavage was holoblastic and equal; blastomeres in two-, four- and eight-cell embryos were compact and 16-cell stage embryos were bi-layered. Late-stage embryos show three cellular regions along the anterior-posterior axis: the anterior hemisphere with heterogeneous cells, a mid-region with cells lying perpendicular to the A-P axis in a collagenous matrix, and small cells at the posterior pole. Unusually for Porifera, multiciliated cells cover all but the posterior pole. It is inferred that fertilization occurs by capture of intact spermatic cysts whose surrounding forceps spicules become trapped in the anisochelae of neighboring sponges. The elongate shape of sperm may be designed to penetrate the loose collagenous mesohyl, such that the arrival of a packet of sperm would lead to simultaneous fertilization of oocytes in a cluster. Loss of the water canal system in carnivorous sponges has allowed the evolution of features that are highly specialized for the habitat of this animal, but such modifications were not necessarily a prerequisite for the subsequent evolution of metazoans. Given the extremely versatile mechanisms of gametogenesis, embryogenesis, and tissue/body structure in sponges, generalizations regarding basal metazoan reproduction, development, and structure must be approached with caution.
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Affiliation(s)
- Ana Riesgo
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada T6G 2E9
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Ramoino P, Gallus L, Paluzzi S, Raiteri L, Diaspro A, Fato M, Bonanno G, Tagliafierro G, Ferretti C, Manconi R. The GABAergic-like system in the marine demosponge Chondrilla nucula. Microsc Res Tech 2008; 70:944-51. [PMID: 17661369 DOI: 10.1002/jemt.20499] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Gamma-amino butyric acid (GABA) is believed to be the principal inhibitory neurotransmitter in the mammalian central nervous system, a function that has been extended to a number of invertebrate systems. The presence of GABA in the marine demosponge Chondrilla nucula was verified using immunofluorescence detection and high-pressure liquid chromatography. A strong GABA-like immunoreactivity (IR) was found associated with choanocytes, exopinacocytes, endopinacocytes lining inhalant, and exhalant canals, as well as in archaeocytes scattered in the mesohyl. The capacity to synthesize GABA from glutamate and to transport it into the vesicles was confirmed by the presence in C. nucula of glutamate decarboxylase (GAD) and vesicular GABA transporters (vGATs), respectively. GAD-like and vGAT-like IR show the same distribution as GABA-like IR. Supporting the similarity between sponge and mammalian proteins, bands with an apparent molecular weight of about 65-67 kDa and 57 kDa were detected using antibodies raised against mammalian GAD and vGAT, respectively. A functional metabotropic GABA(B)-like receptor is also present in C. nucula. Indeed, both GABA(B) R1 and R2 isoforms were detected by immunoblot and immunofluorescence. Also in this case, IR was found in choanocytes, exopinacocytes, and endopinacocytes. The content of GABA in C. nucula amounts to 1225.75 +/- 79 pmol/mg proteins and GABA is released into the medium when sponge cells are depolarized. In conclusion, this study is the first indication of the existence of the GABA biosynthetic enzyme GAD and of the GABA transporter vGAT in sponges, as well as the first demonstration that the neurotransmitter GABA is released extracellularly.
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Affiliation(s)
- Paola Ramoino
- Department for the Study of the Territory and its Resources, University of Genoa, 16132 Genova, Italy.
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Elliott GRD, Leys SP. Coordinated contractions effectively expel water from the aquiferous system of a freshwater sponge. J Exp Biol 2007; 210:3736-48. [DOI: 10.1242/jeb.003392] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
SUMMARY
In response to mechanical stimuli the freshwater sponge Ephydatia muelleri (Demospongiae, Haplosclerida, Spongillidae) carries out a series of peristaltic-like contractions that is effective in expelling clumps of waste material from the aquiferous system. Rates of contraction depend on the region of tissue they are propagating through: 0.3–1 μm s–1 in the peripheral canals, 1–4 μm s–1 in central canals, and 6–122 μm s–1 in the osculum. Faster events include twitches of the entire sponge choanosome and contraction of the sheet-like apical pinacoderm that forms the outer surface of the animal. Contraction events are temporally and spatially coordinated. Constriction of the tip of the osculum leads to dilation of excurrent canals; fields of ostia in the apical pinacoderm close in unison just prior to contraction of the choanosome, apical pinacoderm and osculum. Relaxation returns the osculum, canals and the apical pinacoderm to their normal state, and three such coordinated `inflation–contraction'responses typically follow a single stimulus. Cells in the mesohyl arrest crawling as a wave of contraction passes, suggesting an extracellular signal may pass between cells. Bundles of actin filaments traverse endopinacocytes of the apical pinacoderm. Actin-dense plaques join actin bundles in adjacent pinacocytes to form continuous tracts spanning the whole sponge. The orchestrated and highly repeatable series of contractions illustrates that cellular sponges are capable of coordinated behavioural responses even in the absence of neurons and true muscle. Propagation of the events through the pinacocytes also illustrates the presence of a functional epithelium in cellular sponges. These results suggest that control over a hydrostatic skeleton evolved prior to the origin of nerves and true muscle.
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Affiliation(s)
- Glen R. D. Elliott
- Department of Biological Sciences, University of Alberta, Edmonton,Alberta T6G 2E9, Canada
| | - Sally P. Leys
- Department of Biological Sciences, University of Alberta, Edmonton,Alberta T6G 2E9, Canada
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Gaino E, Baldacconi R, Corriero G. Post-larval development of the commercial sponge Spongia officinalis L. (Porifera, Demospongiae). Tissue Cell 2007; 39:325-34. [PMID: 17826813 DOI: 10.1016/j.tice.2007.06.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2007] [Revised: 06/13/2007] [Accepted: 06/19/2007] [Indexed: 11/29/2022]
Abstract
This study investigated the development of the larvae of Spongia officinalis in experimental conditions, after settlement on plastic substrates, using electron and light microscopy. The released larvae show a dark pigmented ring distinguishes the posterior larval pole. The youngest larvae, covered with a flagellate epithelium, move onwards by rotating on their longitudinal axis. Over time a creeping-like motion prevails, probably linked to the need for settlement. After a free-swimming period of 24-48 h, larvae settle on the artificial substrate by the anterior pole. At settlement, the flagellate epithelium is substituted by flattened cells, which delimit the outermost surface. Post-larvae were reared to about three months. The early phase of post-larval differentiation shows a solid interior mainly consisting of granular cells varying in shape and size. They are included in a dense collagen matrix that contains a conspicuous amount of bacteria. Lacunae are already evident in the initial phase of metamorphosis. In several of them, cell debris and nucleate cells are visible. This feature is consistent with a progressive reduction of the cell mass (autolysis). Neither choanocyte chambers nor canals differentiate. The morphogenetic process leads to a metamorph only consisting of vacuolated cells and collagen fibrils included in a thin fibrous coat.
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Affiliation(s)
- E Gaino
- Università degli Studi di Perugia, Dipartimento di Biologia Cellulare e Ambientale--Via Elce di Sotto--06123 Perugia, Italy
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Abstract
As the most ancient extant metazoans, glass sponges (Hexactinellida) have attracted recent attention in the areas of molecular evolution and the evolution of conduction systems but they are also interesting because of their unique histology: the greater part of their soft tissue consists of a single, multinucleate syncytium that ramifies throughout the sponge. This trabecular syncytium serves both for transport and as a pathway for propagation of action potentials that trigger flagellar arrests in the flagellated chambers. The present chapter is the first comprehensive modern account of this group and covers work going back to the earliest work dealing with taxonomy, gross morphology and histology as well as dealing with more recent studies. The structure of cellular and syncytial tissues and the formation of specialised intercellular junctions are described. Experimental work on reaggregation of dissociated tissues is also covered, a process during which histocompatibility, fusion and syncytialisation have been investigated, and where the role of the cytoskeleton in tissue architecture and transport processes has been studied in depth. The siliceous skeleton is given special attention, with an account of discrete spicules and fused silica networks, their diversity and distribution, their importance as taxonomic features and the process of silication. Studies on particle capture, transport of internalised food objects and disposal of indigestible wastes are reviewed, along with production and control of the feeding current. The electrophysiology of the conduction system coordinating flagellar arrests is described. The review covers salient features of hexactinellid ecology, including an account of habitats, distribution, abundance, growth, seasonal regression, predation, mortality, regeneration, recruitment and symbiotic associations with other organisms. Work on the recently discovered hexactinellid reefs of Canada's western continental shelf, analogues of long-extinct Jurassic sponge reefs, is given special attention. Reproductive biology is another area that has benefited from recent investigations. Seasonality, gametogenesis, embryogenesis, differentiation and larval biology are now understood in broad outline, at least for some species. The process whereby the cellular early larva becomes syncytial is described. A final section deals with the classification of recent and fossil glass sponges, phylogenetic relationships within the Hexactinellida and the phylogenetic position of the group within the Porifera. Palaeontological aspects are covered in so far as they are relevant to these topics.
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Affiliation(s)
- S P Leys
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
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Leys SP, Eerkes-Medrano DI. Feeding in a calcareous sponge: particle uptake by pseudopodia. THE BIOLOGICAL BULLETIN 2006; 211:157-71. [PMID: 17062875 DOI: 10.2307/4134590] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Sponges are considered to be filter feeders like their nearest protistan relatives, the choanoflagellates. Specialized "sieve" cells (choanocytes) have an apical collar of tightly spaced, rodlike microvilli that surround a long flagellum. The beat of the flagellum is believed to draw water through this collar, but how particles caught on the collar are brought to the cell surface is unknown. We have studied the interactions that occur between choanocytes and introduced particles in the large feeding chambers of a syconoid calcareous sponge. Of all particles, only 0.1-microm latex microspheres adhered to the collar microvilli in large numbers, but these were even more numerous on the choanocyte surface. Few large particles (0.5- and 1.0-microm beads and bacteria) contacted the collar microvilli; most were phagocytosed by lamellipodia at the lateral or apical cell surface, and clumps of particles were engulfed by pseudopodial extensions several micrometers from the cell surface. Although extensions of the choanocyte apical surface up to 16 microm long were found, most were 4 microm long, twice the height of the collar microvilli. These observations offer a different view of particle uptake in sponges, and suggest that, at least in syconoid sponges, uptake of particles is less dependent on the strictly sieving function of the collar microvilli.
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Affiliation(s)
- Sally P Leys
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada, T6G 2E9.
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