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Moroz LL. Syncytial nets vs. chemical signaling: emerging properties of alternative integrative systems. Front Cell Dev Biol 2023; 11:1320209. [PMID: 38125877 PMCID: PMC10730927 DOI: 10.3389/fcell.2023.1320209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 11/22/2023] [Indexed: 12/23/2023] Open
Affiliation(s)
- Leonid L. Moroz
- Department of Neuroscience, University of Florida, Gainesville, FL, United States
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL, United States
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Moroz LL, Romanova DY. Chemical cognition: chemoconnectomics and convergent evolution of integrative systems in animals. Anim Cogn 2023; 26:1851-1864. [PMID: 38015282 PMCID: PMC11106658 DOI: 10.1007/s10071-023-01833-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/16/2023] [Indexed: 11/29/2023]
Abstract
Neurons underpin cognition in animals. However, the roots of animal cognition are elusive from both mechanistic and evolutionary standpoints. Two conceptual frameworks both highlight and promise to address these challenges. First, we discuss evidence that animal neural and other integrative systems evolved more than once (convergent evolution) within basal metazoan lineages, giving us unique experiments by Nature for future studies. The most remarkable examples are neural systems in ctenophores and neuroid-like systems in placozoans and sponges. Second, in addition to classical synaptic wiring, a chemical connectome mediated by hundreds of signal molecules operates in tandem with neurons and is the most information-rich source of emerging properties and adaptability. The major gap-dynamic, multifunctional chemical micro-environments in nervous systems-is not understood well. Thus, novel tools and information are needed to establish mechanistic links between orchestrated, yet cell-specific, volume transmission and behaviors. Uniting what we call chemoconnectomics and analyses of the cellular bases of behavior in basal metazoan lineages arguably would form the foundation for deciphering the origins and early evolution of elementary cognition and intelligence.
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Affiliation(s)
- Leonid L Moroz
- Department of Neuroscience, University of Florida, Gainesville, USA.
- Whitney Laboratory for Marine Bioscience, University of Florida, Saint Augustine, USA.
| | - Daria Y Romanova
- Institute of Higher Nervous Activity and Neurophysiology of RAS, Moscow, Russia
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Maegele I, Rupp S, Özbek S, Guse A, Hambleton EA, Holstein TW. A predatory gastrula leads to symbiosis-independent settlement in Aiptasia. Proc Natl Acad Sci U S A 2023; 120:e2311872120. [PMID: 37748072 PMCID: PMC10556626 DOI: 10.1073/pnas.2311872120] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 08/19/2023] [Indexed: 09/27/2023] Open
Abstract
The planula larvae of the sea anemone Aiptasia have so far not been reported to complete their life cycle by undergoing metamorphosis into adult forms. This has been a major obstacle in their use as a model for coral-dinoflagellate endosymbiosis. Here, we show that Aiptasia larvae actively feed on crustacean nauplii, displaying a preference for live prey. This feeding behavior relies on functional stinging cells, indicative of complex neuronal control. Regular feeding leads to significant size increase, morphological changes, and efficient settlement around 14 d postfertilization. Surprisingly, the presence of dinoflagellate endosymbionts does not affect larval growth or settlement dynamics but is crucial for sexual reproduction. Our findings finally close Aiptasia's life cycle and highlight the functional nature of its larvae, as in Haeckel's Gastrea postulate, yet reveal its active carnivory, thus contributing to our understanding of early metazoan evolution.
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Affiliation(s)
- Ira Maegele
- Molecular Evolution and Genomics, Centre for Organismal Studies, Heidelberg University, 69120Heidelberg, Germany
| | - Sebastian Rupp
- Quantitative Organismic Networks, Department of Biology, Ludwig-Maximilians-University Munich, 82152Martinsried, Germany
| | - Suat Özbek
- Molecular Evolution and Genomics, Centre for Organismal Studies, Heidelberg University, 69120Heidelberg, Germany
| | - Annika Guse
- Quantitative Organismic Networks, Department of Biology, Ludwig-Maximilians-University Munich, 82152Martinsried, Germany
| | - Elizabeth A. Hambleton
- Division of Microbial Ecology, Centre for Microbiology and Environmental Systems Science, University of Vienna, 1030Vienna, Austria
| | - Thomas W. Holstein
- Molecular Evolution and Genomics, Centre for Organismal Studies, Heidelberg University, 69120Heidelberg, Germany
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Moroz LL, Romanova DY, Kohn AB. Neural versus alternative integrative systems: molecular insights into origins of neurotransmitters. Philos Trans R Soc Lond B Biol Sci 2021; 376:20190762. [PMID: 33550949 PMCID: PMC7935107 DOI: 10.1098/rstb.2019.0762] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/23/2020] [Indexed: 12/18/2022] Open
Abstract
Transmitter signalling is the universal chemical language of any nervous system, but little is known about its early evolution. Here, we summarize data about the distribution and functions of neurotransmitter systems in basal metazoans as well as outline hypotheses of their origins. We explore the scenario that neurons arose from genetically different populations of secretory cells capable of volume chemical transmission and integration of behaviours without canonical synapses. The closest representation of this primordial organization is currently found in Placozoa, disk-like animals with the simplest known cell composition but complex behaviours. We propose that injury-related signalling was the evolutionary predecessor for integrative functions of early transmitters such as nitric oxide, ATP, protons, glutamate and small peptides. By contrast, acetylcholine, dopamine, noradrenaline, octopamine, serotonin and histamine were recruited as canonical neurotransmitters relatively later in animal evolution, only in bilaterians. Ligand-gated ion channels often preceded the establishment of novel neurotransmitter systems. Moreover, lineage-specific diversification of neurotransmitter receptors occurred in parallel within Cnidaria and several bilaterian lineages, including acoels. In summary, ancestral diversification of secretory signal molecules provides unique chemical microenvironments for behaviour-driven innovations that pave the way to complex brain functions and elementary cognition. This article is part of the theme issue 'Basal cognition: multicellularity, neurons and the cognitive lens'.
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Affiliation(s)
- Leonid L. Moroz
- Department of Neuroscience, McKnight Brain Institute and Whitney laboratory, University of Florida, 9505 Ocean shore Blvd, St Augustine, FL 32080, USA
| | - Daria Y. Romanova
- Laboratory of Cellular Neurobiology of Learning, Institute of Higher Nervous Activity and Neurophysiology of RAS, 5A Butlerova Street, Moscow 117485, Russia
| | - Andrea B. Kohn
- Department of Neuroscience, McKnight Brain Institute and Whitney laboratory, University of Florida, 9505 Ocean shore Blvd, St Augustine, FL 32080, USA
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Leys SP, Mah JL, McGill PR, Hamonic L, De Leo FC, Kahn AS. Sponge Behavior and the Chemical Basis of Responses: A Post-Genomic View. Integr Comp Biol 2020; 59:751-764. [PMID: 31268144 DOI: 10.1093/icb/icz122] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Sponges perceive and respond to a range of stimuli. How they do this is still difficult to pin down despite now having transcriptomes and genomes of an array of species. Here we evaluate the current understanding of sponge behavior and present new observations on sponge activity in situ. We also explore biosynthesis pathways available to sponges from data in genomes/transcriptomes of sponges and other non-bilaterians with a focus on exploring the role of chemical signaling pathways mediating sponge behavior and how such chemical signal pathways may have evolved. Sponge larvae respond to light but opsins are not used, nor is there a common photoreceptor molecule or mechanism used across sponge groups. Other cues are gravity and chemicals. In situ recordings of behavior show that both shallow and deep-water sponges move a lot over minutes and hours, and correlation of behavior with temperature, pressure, oxygen, and water movement suggests that at least one sponge responds to changes in atmospheric pressure. The sensors for these cues as far as we know are individual cells and, except in the case of electrical signaling in Hexactinellida, these most likely act as independent effectors, generating a whole-body reaction by the global reach of the stimulus to all parts of the animal. We found no evidence for use of conventional neurotransmitters such as serotonin and dopamine. Intriguingly, some chemicals synthesized by symbiont microbes could mean other more complex signaling occurs, but how that interplay might happen is not understood. Our review suggests chemical signaling pathways found in sponges do not reflect loss of a more complex set.
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Affiliation(s)
- Sally P Leys
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada T6G 2E9
| | - Jasmine L Mah
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada T6G 2E9.,Department of Ecology and Evolutionary Biology, Yale University, 165 Prospect Street, New Haven, CT 06511, USA
| | - Paul R McGill
- Monterey Bay Aquarium Research Institute, 7700 Sandholdt Road, Moss Landing, CA 95039, USA
| | - Laura Hamonic
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada T6G 2E9
| | - Fabio C De Leo
- Ocean Networks Canada, University of Victoria, Queenswood Campus 100-2474 Arbutus Road, Victoria, British Columbia, Canada V8N 1V8.,Department of Biology, University of Victoria, PO Box 3080, Victoria, British Columbia, Canada V8W 2Y2
| | - Amanda S Kahn
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada T6G 2E9.,Monterey Bay Aquarium Research Institute, 7700 Sandholdt Road, Moss Landing, CA 95039, USA.,Moss Landing Marine Laboratories, 8272 Moss Landing Road, Moss Landing, CA 95039, USA
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