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Krivenko OV, Kuleshova ON, Baiandina IS. Light sensitivity in Beroidae ctenophores: Insights from laboratory studies and genomics. Comp Biochem Physiol A Mol Integr Physiol 2024; 296:111694. [PMID: 38992417 DOI: 10.1016/j.cbpa.2024.111694] [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: 01/24/2024] [Revised: 06/05/2024] [Accepted: 07/01/2024] [Indexed: 07/13/2024]
Abstract
Light detection underlies a variety of animal behaviors, including those related to spatial orientation, feeding, avoidance of predators, and reproduction. Ctenophores are likely the oldest animal group in which light sensitivity based on opsins evolved, so they may still have the ancestral molecular mechanisms for photoreception. However, knowledge about ctenophore photosensitivity, associated morphological structures, molecular mechanisms involved, and behavioral reactions is limited and fragmented. We present the initial experiments on the responses of adult Beroe ovata to high-intensity light exposure with different spectra and photosensitivity in various parts of the animal's body. Ctenophores have shown a consistent behavioral response when their aboral organ is exposed to a household-grade laser in the violet spectrum. To investigate the genes responsible for the photosensitivity of Beroidae, we have analyzed transcriptome and genome-wide datasets. We identified three opsins in Beroe that are homologous to those found in Mnemiopsis leidyi (Lobata) and Pleurobrachia bachei (Cydippida). These opsins form clades Ctenopsin1, 2, and 3, respectively. Ctenopsin3 is significantly distinct from other ctenophore opsins and clustered outside the main animal opsin groups. The Ctenopsin1 and Ctenopsin2 groups are sister clusters within the canonical animal opsin tree. These two groups could have originated from gene duplication in the common ancestor of the species we studied and then developed independently in different lineages of Ctenophores. So far, there is no evidence of additional expansion of the opsin family in ctenophore evolution. The involvement of ctenophore opsins in photoreception is discussed by analyzing their protein structures.
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Affiliation(s)
- Olga V Krivenko
- Laboratory of functional genomics, A.O. Kovalevsky Institute of Biology of the Southern Seas of RAS, Moscow, Russia.
| | - Olga N Kuleshova
- Laboratory of functional genomics, A.O. Kovalevsky Institute of Biology of the Southern Seas of RAS, Moscow, Russia
| | - Iuliia S Baiandina
- Laboratory of functional genomics, A.O. Kovalevsky Institute of Biology of the Southern Seas of RAS, Moscow, Russia
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Sachkova MY. Evolutionary origin of the nervous system from Ctenophora prospective. Evol Dev 2024; 26:e12472. [PMID: 38390763 DOI: 10.1111/ede.12472] [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: 08/23/2023] [Revised: 02/09/2024] [Accepted: 02/10/2024] [Indexed: 02/24/2024]
Abstract
Nervous system is one of the key adaptations underlying the evolutionary success of the majority of animal groups. Ctenophores (or comb jellies) are gelatinous marine invertebrates that were probably the first lineage to diverge from the rest of animals. Due to the key phylogenetic position and multiple unique adaptations, the noncentralized nervous system of comb jellies has been in the center of the debate around the origin of the nervous system in the animal kingdom and whether it happened only once or twice. Here, we discuss the latest findings in ctenophore neuroscience and multiple challenges on the way to build a clear evolutionary picture of the origin of the nervous system.
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Affiliation(s)
- Maria Y Sachkova
- School of Biological Sciences, University of Bristol, Bristol, UK
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Vargas A, DeBiasse M, Dykes L, Edgar A, Hayes T, Groso D, Babonis L, Martindale M, Ryan J. Morphological and dietary changes encoded in the genome of Beroe ovata, a ctenophore-eating ctenophore. NAR Genom Bioinform 2024; 6:lqae072. [PMID: 38895105 PMCID: PMC11184263 DOI: 10.1093/nargab/lqae072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Revised: 05/03/2024] [Accepted: 05/30/2024] [Indexed: 06/21/2024] Open
Abstract
As the sister group to all other animals, ctenophores (comb jellies) are important for understanding the emergence and diversification of numerous animal traits. Efforts to explore the evolutionary processes that promoted diversification within Ctenophora are hindered by undersampling genomic diversity within this clade. To address this gap, we present the sequence, assembly and initial annotation of the genome of Beroe ovata. Beroe possess unique morphology, behavior, ecology and development. Unlike their generalist carnivorous kin, beroid ctenophores feed exclusively on other ctenophores. Accordingly, our analyses revealed a loss of chitinase, an enzyme critical for the digestion of most non-ctenophore prey, but superfluous for ctenophorivores. Broadly, our genomic analysis revealed that extensive gene loss and changes in gene regulation have shaped the unique biology of B. ovata. Despite the gene losses in B. ovata, our phylogenetic analyses on photosensitive opsins and several early developmental regulatory genes show that these genes are conserved in B. ovata. This additional sampling contributes to a more complete reconstruction of the ctenophore ancestor and points to the need for extensive comparisons within this ancient and diverse clade of animals. To promote further exploration of these data, we present BovaDB (http://ryanlab.whitney.ufl.edu/bovadb/), a portal for the B. ovata genome.
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Affiliation(s)
- Alexandra M Vargas
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL 32080, USA
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC 28223, USA
| | - Melissa B DeBiasse
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL 32080, USA
- Department of Biology, Radford University, Radford, VA 24142, USA
| | - Lana L Dykes
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL 32080, USA
| | - Allison Edgar
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL 32080, USA
- Federated Department of Biological Sciences, New Jersey Institute of Technology, Newark, NJ 07102, USA
| | - T Danielle Hayes
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL 32080, USA
| | - Daniel J Groso
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL 32080, USA
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
- Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
| | - Leslie S Babonis
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA
| | - Mark Q Martindale
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL 32080, USA
- Department of Biology, University of Florida, Gainesville, FL 32611, USA
| | - Joseph F Ryan
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL 32080, USA
- Department of Biology, University of Florida, Gainesville, FL 32611, USA
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Burkhardt P, Colgren J, Medhus A, Digel L, Naumann B, Soto-Angel JJ, Nordmann EL, Sachkova MY, Kittelmann M. Syncytial nerve net in a ctenophore adds insights on the evolution of nervous systems. Science 2023; 380:293-297. [PMID: 37079688 DOI: 10.1126/science.ade5645] [Citation(s) in RCA: 25] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/22/2023]
Abstract
A fundamental breakthrough in neurobiology has been the formulation of the neuron doctrine by Santiago Ramón y Cajal, which stated that the nervous system is composed of discrete cells. Electron microscopy later confirmed the doctrine and allowed the identification of synaptic connections. In this work, we used volume electron microscopy and three-dimensional reconstructions to characterize the nerve net of a ctenophore, a marine invertebrate that belongs to one of the earliest-branching animal lineages. We found that neurons in the subepithelial nerve net have a continuous plasma membrane that forms a syncytium. Our findings suggest fundamental differences of nerve net architectures between ctenophores and cnidarians or bilaterians and offer an alternative perspective on neural network organization and neurotransmission.
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Affiliation(s)
- Pawel Burkhardt
- Michael Sars Centre, University of Bergen, 5008 Bergen, Norway
| | - Jeffrey Colgren
- Michael Sars Centre, University of Bergen, 5008 Bergen, Norway
| | - Astrid Medhus
- Michael Sars Centre, University of Bergen, 5008 Bergen, Norway
| | - Leonid Digel
- Michael Sars Centre, University of Bergen, 5008 Bergen, Norway
| | - Benjamin Naumann
- Institut für Biowissenschaften, Allgemeine und Spezielle Zoologie, Universität Rostock, 18055 Rostock, Germany
| | | | | | | | - Maike Kittelmann
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, UK
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