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Mapalo MA, Game M, Smith FW, Ortega-Hernández J. Expression of distal limb patterning genes in Hypsibius exemplaris indicate regionalization and suggest distal identity of tardigrade legs. EvoDevo 2024; 15:15. [PMID: 39538290 PMCID: PMC11562647 DOI: 10.1186/s13227-024-00235-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2024] [Accepted: 10/21/2024] [Indexed: 11/16/2024] Open
Abstract
BACKGROUND Panarthropods, a major group of invertebrate animals comprised of arthropods, onychophorans, and tardigrades, are the only limb-bearing members of Ecdysozoa. The complexity and versatility of panarthropod paired limbs has prompted great interest in their development to better understand the formation of these structures and the genes involved in this process. However, studies of limb patterning and development are overwhelmingly focused on arthropods, followed by select work on onychophorans but almost entirely lacking for tardigrades. This model organism bias is inherently limited and precludes a comparative analysis of how panarthropod legs originated, have evolved, and the likely limb patterning genes present in the earliest panarthropod ancestors. In this study, we investigated tardigrade homologs of seven arthropod distal limb patterning genes (apterous, aristaless, BarH1, clawless, Lim1, rotund, and spineless) to better characterize tardigrade limb development in a comparative context. RESULTS We detected homologs of all seven genes in the eutardigrade Hypsibius exemplaris and heterotardigrade Echiniscoides cf. sigismundi suggesting their conservation in both tardigrade lineages. Hybridization chain reaction experiments in H. exemplaris reveal a regionalized expression pattern for the genes aristaless, BarH1, clawless, rotund and spineless. CONCLUSION The observed regionalized expression of the distal limb patterning genes in H. exemplaris might reflect the external morphological features of tardigrade legs, such as the distal claws, sensory organs in the proximal region, and specific muscle attachment sites. The comparison between the expression of these limb patterning genes in H. exemplaris relative to other panarthropods suggests their conserved role in the last common panarthropod ancestor, such as establishing the distal limb end and the distribution of sensory structures. Our results support the hypothesis that tardigrade legs are homologous to the distal region of other panarthropod limbs, as suggested by previous work on the expression of leg gap genes in H. exemplaris.
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Affiliation(s)
- Marc A Mapalo
- Museum of Comparative Zoology, Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
| | - Mandy Game
- Department of Ecology & Evolutionary Biology, University of Connecticut, Storrs, CT, USA
| | - Frank W Smith
- Biology Department, University of North Florida, Jacksonville, FL, USA.
| | - Javier Ortega-Hernández
- Museum of Comparative Zoology, Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA.
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Chellapandian H, Jeyachandran S. Leveraging tardigrade proteins Dsup and CAHS D for enhanced neural protection in neurosurgery and neuroscience. Neurosurg Rev 2024; 47:686. [PMID: 39325258 DOI: 10.1007/s10143-024-02901-3] [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: 09/02/2024] [Revised: 09/04/2024] [Accepted: 09/15/2024] [Indexed: 09/27/2024]
Abstract
Tardigrades are microscopic organisms known for their remarkable resilience to extreme environmental conditions, including radiation and desiccation. Two key proteins, Dsup (Damage suppressor protein) and CAHS D (Cytoplasmic Abundant Heat Soluble protein D), play crucial roles in this resilience. Dsup protects DNA from radiation-induced damage, while CAHS D stabilizes cellular structures during desiccation by interacting with, but not retaining, water. These unique mechanisms have significant potential applications in neurosurgery and neuroscience. Dsup could inspire the development of protective agents for neural tissues during radiation-based treatments, minimizing collateral damage and improving patient outcomes. Meanwhile, CAHS D's stabilization properties could lead to new neuroprotective strategies, safeguarding brain cells under stress. Together, these tardigrade proteins offer innovative solutions for enhancing neural protection, opening new avenues for treating neurological conditions and improving the safety and efficacy of neurosurgical procedures.
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Affiliation(s)
- Hethesh Chellapandian
- Lab in Biotechnology and Biosignal Transduction, Department of Orthodontics, Saveetha Dental College and Hospital, Saveetha Institute of Medical and Technical Sciences (SIMATS), Saveetha University, Chennai-77, Tamil Nadu, India
| | - Sivakamavalli Jeyachandran
- Lab in Biotechnology and Biosignal Transduction, Department of Orthodontics, Saveetha Dental College and Hospital, Saveetha Institute of Medical and Technical Sciences (SIMATS), Saveetha University, Chennai-77, Tamil Nadu, India.
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Vecchi M, Calhim S. Patterns of sexual dimorphism in the armoured tardigrades. Biol Lett 2024; 20:20240301. [PMID: 39255843 PMCID: PMC11387062 DOI: 10.1098/rsbl.2024.0301] [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] [Received: 05/28/2024] [Revised: 07/05/2024] [Accepted: 07/30/2024] [Indexed: 09/12/2024] Open
Abstract
Sexual dimorphism is widespread among animals, with diverse patterns and proposed explanations observed across the Tree of Life. Here we present the first formal analysis of the patterns of sexual dimorphism in body size and cephalic sensory appendages across 40 species (from 10 genera) of armoured tardigrades (Echiniscidae). Phylogenetic signal was found for body size traits and the cephalic papilla relative size, indicating that the association between these traits between the sexes has high evolutionary persistence. The Echiniscidae body size dimorphism is generally female-biased, which would be in accordance with the fecundity hypothesis. No strong evidence of allometric patterns of body size sexual dimorphism was found. In contrast, some of the cephalic appendages show male-biased sexual dimorphism, particularly those that, by being more innervated, are thought to function as chemodetection organs used by males during mate search. The latter is consistent with the sexual selection hypothesis. As the first systematic quantification and analysis of the patterns of sexual dimorphism in the phylum Tardigrada, this study provides important insights into their ecology and evolution, such as corroborating the suggestion that cephalic appendages evolved for mate searching.
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Affiliation(s)
- Matteo Vecchi
- Department of Biological and Environmental Science, University of Jyväskylä, PO Box 35, JyväskyläFI-40014, Finland
- Institute of Systematics and Evolution of Animals, Polish Academy of Sciences, Sławkowska 17, Kraków31-016, Poland
| | - Sara Calhim
- Department of Biological and Environmental Science, University of Jyväskylä, PO Box 35, JyväskyläFI-40014, Finland
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Flinn BB, O'Dell HM, Joseph KM, Smythers AL, Neff DP, Hicks LM, Norton ML, Kolling DRJ. Fluorescence shadow imaging of Hypsibius exemplaris reveals morphological differences between sucrose- and CaCl 2-induced osmobiotes. Sci Rep 2024; 14:11845. [PMID: 38782941 PMCID: PMC11116526 DOI: 10.1038/s41598-024-61374-y] [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] [Received: 02/26/2024] [Accepted: 05/06/2024] [Indexed: 05/25/2024] Open
Abstract
Tardigrades are renowned for their ability to survive a wide array of environmental stressors. In particular, tardigrades can curl in on themselves while losing a significant proportion of their internal water content to form a structure referred to as a tun. In surviving varying conditions, tardigrades undergo distinct morphological transformations that could indicate different mechanisms of stress sensing and tolerance specific to the stress condition. Methods to effectively distinguish between morphological transformations, including between tuns induced by different stress conditions, are lacking. Herein, an approach for discriminating between tardigrade morphological states is developed and utilized to compare sucrose- and CaCl2-induced tuns, using the model species Hypsibius exemplaris. A novel approach of shadow imaging with confocal laser scanning microscopy enabled production of three-dimensional renderings of Hys. exemplaris in various physiological states resulting in volume measurements. Combining these measurements with qualitative morphological analysis using scanning electron microscopy revealed that sucrose- and CaCl2-induced tuns have distinct morphologies, including differences in the amount of water expelled during tun formation. Further, varying the concentration of the applied stressor did not affect the amount of water lost, pointing towards water expulsion by Hys. exemplaris being a controlled process that is adapted to the specific stressors.
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Affiliation(s)
- Brendin B Flinn
- Department of Chemistry, Marshall University, Huntington, WV, USA
| | - Hayden M O'Dell
- Department of Chemistry, Marshall University, Huntington, WV, USA
| | - Kara M Joseph
- Department of Chemistry, Marshall University, Huntington, WV, USA
| | - Amanda L Smythers
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - David P Neff
- Department of Chemistry, Marshall University, Huntington, WV, USA
| | - Leslie M Hicks
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Michael L Norton
- Department of Chemistry, Marshall University, Huntington, WV, USA
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Janelt K, Poprawa I. Organisation of the nervous system in cysts of the freshwater tardigrade Thulinius ruffoi (Parachela, Isohypsibioidea: Doryphoribiidae). J Anat 2024; 244:654-666. [PMID: 38131103 PMCID: PMC10941535 DOI: 10.1111/joa.13994] [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] [Received: 08/03/2023] [Revised: 11/26/2023] [Accepted: 11/27/2023] [Indexed: 12/23/2023] Open
Abstract
Encystment is a natural process that involves cyst formation, and at least some species of tardigrades can form cysts. However, the encystment process and cyst structure among tardigrades are still poorly understood. Despite some aspects of the encysted animals' systems organisation being examined in the past, the morphology and structure of the nervous system have never been thoroughly investigated. This study covers anatomical, histological and morphological details and proposes physiological aspects of the nervous system in encysted Thulinius ruffoi up to 11 months duration in encystment. This is the first record of the nervous system organisation in a species belonging to the family Doryphoribiidae. The cyst formation results in morphological changes in the nervous system. It comprises central and peripheral elements, which may be observable even after many months since the cyst formation. Based on the nervous system's organisation in cysts, there is no sign that histolysis is a part of encystment.
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Affiliation(s)
- Kamil Janelt
- Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia in Katowice, Katowice, Poland
- Department of Medical Genetics, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Katowice, Poland
| | - Izabela Poprawa
- Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia in Katowice, Katowice, Poland
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Kihm JH, Zawierucha K, Rho HS, Park TYS. Homology of the head sensory structures between Heterotardigrada and Eutardigrada supported in a new species of water bear (Ramazzottiidae: Ramazzottius). ZOOLOGICAL LETTERS 2023; 9:22. [PMID: 38012802 PMCID: PMC10680360 DOI: 10.1186/s40851-023-00221-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 10/05/2023] [Indexed: 11/29/2023]
Abstract
Phylum Tardigrada is represented by microscopic eight-legged panarthropods that inhabit terrestrial and marine environments. Although tardigrades are emerging model animals for areas of research including physiology, evolutionary biology, and astrobiology, knowledge of their external morphology remains insufficient. For instance, homologies between marine and terrestrial relatives largely remain unexplored. In the present study we provide detailed pictures of the head sensory organs in a new tardigrade, Ramazzottius groenlandensis sp. nov. Specimens were collected from a mixed moss and lichen sample on Ella Island, East Greenland. The new species differs from congeneric species in the presence of polygonal sculpturing on the dorsal cuticle, which is accentuated in the posterior region of the body, a lateral papilla on leg IV, and distinctive egg morphology. A Bayesian phylogenetic analysis (18S rRNA + 28S rRNA + COI) places the new species within the genus Ramazzottius with high confidence. Interestingly, the new species shows a full set of well-developed cephalic organs, which correspond to all sensory fields found in eutardigrades. Details on the full set of head organs were present only for heterotardigrades. The surface of these organs is covered with small pores, which presumably play a sensory role. This discovery suggests the homology of head sensory structures between heterotardigrades and eutardigrades, implying that the distinctive arrangement and positioning of sensory organs on the head is a plesiomorphic feature of tardigrades. Moreover, we find that the Ramazzottius oberhaeuseri morphotype forms a morphogroup, not a monophyletic species complex.
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Affiliation(s)
- Ji-Hoon Kihm
- Division of Earth Sciences, Korea Polar Research Institute, 26 Songdomirae-ro, Yeonsu-gu, Incheon, 21990, Korea.
| | - Krzysztof Zawierucha
- Department of Animal Taxonomy and Ecology, Faculty of Biology, Adam Mickiewicz University, Uniwersytetu Poznańskiego 6, Poznań, 61-614, Poland
| | - Hyun Soo Rho
- East Sea Environmental Research Center, East Sea Research Institute, Korea Institute of Ocean Science & Technology, 48 Haeyanggwahak-gil, Uljin, Gyeongsangbuk-do, 36315, Korea
| | - Tae-Yoon S Park
- Division of Earth Sciences, Korea Polar Research Institute, 26 Songdomirae-ro, Yeonsu-gu, Incheon, 21990, Korea
- Polar Sciences, University of Science and Technology, 217 Gajeong-ro, Yuseong-gu, Daejeon, 34113, Korea
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Grollmann MM, Jørgensen A, Møbjerg N. Actinarctus doryphorus (Tanarctidae) DNA barcodes and phylogenetic reinvestigation of Arthrotardigrada with new A. doryphorus and Echiniscoididae sequences. Zootaxa 2023; 5284:351-363. [PMID: 37518733 DOI: 10.11646/zootaxa.5284.2.7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Indexed: 08/01/2023]
Abstract
Little is still known about the diversity and evolution of marine arthrotardigrades, as they are generally difficult to sample, resulting in a limited amount of molecular data for barcoding and phylogenetic studies. With the current study, we provide the first investigation into COI haplotype diversity in a marine tanarctid and at the same time readdress arthrotardigrade phylogeny. Specifically, we provide COI mtDNA, 18S and 28S rDNA sequences from a population of Actinarctus doryphorus (Tanarctidae) sampled off the coast of Roscoff, France and further provide new 18S sequences from two marine echiniscoidids. A. doryphorus COI sequences confirmed the presence of a single species and further revealed five haplotypes shared among nine sequenced individuals. Our 18S and 28S rDNA datasets were individually and combined analysed with Bayesian inference and Maximum Likelihood. Actinarctus doryphorus was placed together with Tanarctus sequences within a maximally supported Tanarctidae, confirming previous interpretations that the clade is distinct from Halechiniscidae. Although several studies in recent decades have concluded that the marine arthrotardigrades are paraphyletic, recent studies have argued that the clade may not be paraphyletic. Our phylogenetic analyses consistently inferred Arthrotardigrada as paraphyletic, as the clade includes the monophyletic Echiniscoidea. Accordingly, we propose that it is time to suppress the order Arthrotardigrada as it clearly does not reflect tardigrade phylogeny.
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Affiliation(s)
| | | | - Nadja Møbjerg
- Department of Biology; University of Copenhagen; Denmark.
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Gąsiorek P. Eventually tested: Phylogenetic position of “Testechiniscus” meridionalis (Murray, 1906) (Heterotardigrada) revealed. ZOOL ANZ 2023. [DOI: 10.1016/j.jcz.2023.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
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Lev O, Edgecombe GD, Chipman AD. Serial Homology and Segment Identity in the Arthropod Head. Integr Org Biol 2022; 4:obac015. [PMID: 35620450 PMCID: PMC9128542 DOI: 10.1093/iob/obac015] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The anterior-most unit of the crown-group arthropod body plan includes three segments, the pre-gnathal segments, that contain three neuromeres that together comprise the brain. Recent work on the development of this anterior region has shown that its three units exhibit many developmental differences to the more posterior segments, to the extent that they should not be considered serial homologs. Building on this revised understanding of the development of the pre-gnathal segments, we suggest a novel scenario for arthropod head evolution. We posit an expansion of an ancestral single-segmented head at the transition from Radiodonta to Deuteropoda in the arthropod stem group. The expanded head subdivided into three segmental units, each maintaining some of the structures of the ancestral head. This scenario is consistent with what we know of head evolution from the fossil record and helps reconcile some of the debates about early arthropod evolution.
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Affiliation(s)
- Oren Lev
- The Dept. of Ecology, Evolution & Behavior, The Silberman Institute of Life Sciences, The Hebrew University of Jerusalem
| | - Gregory D Edgecombe
- Department of Earth Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD, UK
| | - Ariel D Chipman
- The Dept. of Ecology, Evolution & Behavior, The Silberman Institute of Life Sciences, The Hebrew University of Jerusalem
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Martin C, Jahn H, Klein M, Hammel JU, Stevenson PA, Homberg U, Mayer G. The velvet worm brain unveils homologies and evolutionary novelties across panarthropods. BMC Biol 2022; 20:26. [PMID: 35073910 PMCID: PMC9136957 DOI: 10.1186/s12915-021-01196-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 11/16/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The evolution of the brain and its major neuropils in Panarthropoda (comprising Arthropoda, Tardigrada and Onychophora) remains enigmatic. As one of the closest relatives of arthropods, onychophorans are regarded as indispensable for a broad understanding of the evolution of panarthropod organ systems, including the brain, whose anatomical and functional organisation is often used to gain insights into evolutionary relations. However, while numerous recent studies have clarified the organisation of many arthropod nervous systems, a detailed investigation of the onychophoran brain with current state-of-the-art approaches is lacking, and further inconsistencies in nomenclature and interpretation hamper its understanding. To clarify the origins and homology of cerebral structures across panarthropods, we analysed the brain architecture in the onychophoran Euperipatoides rowelli by combining X-ray micro-computed tomography, histology, immunohistochemistry, confocal microscopy, and three-dimensional reconstruction. RESULTS Here, we use this detailed information to generate a consistent glossary for neuroanatomical studies of Onychophora. In addition, we report novel cerebral structures, provide novel details on previously known brain areas, and characterise further structures and neuropils in order to improve the reproducibility of neuroanatomical observations. Our findings support homology of mushroom bodies and central bodies in onychophorans and arthropods. Their antennal nerve cords and olfactory lobes most likely evolved independently. In contrast to previous reports, we found no evidence for second-order visual neuropils, or a frontal ganglion in the velvet worm brain. CONCLUSION We imaged the velvet worm nervous system at an unprecedented level of detail and compiled a comprehensive glossary of known and previously uncharacterised neuroanatomical structures to provide an in-depth characterisation of the onychophoran brain architecture. We expect that our data will improve the reproducibility and comparability of future neuroanatomical studies.
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Affiliation(s)
- Christine Martin
- Department of Zoology, Institute of Biology, University of Kassel, 34132, Kassel, Germany.
| | - Henry Jahn
- Department of Zoology, Institute of Biology, University of Kassel, 34132, Kassel, Germany
| | - Mercedes Klein
- Department of Zoology, Institute of Biology, University of Kassel, 34132, Kassel, Germany
| | - Jörg U Hammel
- Institute of Materials Physics, Helmholtz-Zentrum hereon, 21502, Geesthacht, Germany
| | - Paul A Stevenson
- Physiology of Animals and Behaviour, Institute of Biology, University of Leipzig, 04103, Leipzig, Germany
| | - Uwe Homberg
- Department of Biology, Animal Physiology, Philipps-Universität Marburg, 35043, Marburg, Germany
- Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus Liebig University Giessen, 35032, Marburg, Germany
| | - Georg Mayer
- Department of Zoology, Institute of Biology, University of Kassel, 34132, Kassel, Germany.
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