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Nagwani AK, Melosik I, Kaczmarek Ł, Kmita H. Recovery from anhydrobiosis in the tardigrade Paramacrobiotus experimentalis: Better to be young than old and in a group than alone. Heliyon 2024; 10:e26807. [PMID: 38434295 PMCID: PMC10907786 DOI: 10.1016/j.heliyon.2024.e26807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 12/10/2023] [Accepted: 02/20/2024] [Indexed: 03/05/2024] Open
Abstract
Desiccation-tolerant organisms can survive dehydration in a state of anhydrobiosis. Tardigrades can recover from anhydrobiosis at any life stage and are considered among the toughest animals on Earth. However, the factors that influence recovery from anhydrobiosis are not well understood. The study aimed to evaluate the effect of sex, age, the presence of other individuals and the combination of the number and duration of anhydrobiosis episodes on the recovery of Paramacrobiotus experimentalis. The activity of 1200 individuals for up to 48 h after rehydration was evaluated using analysis of variance (ANOVA). Age was the main factor influencing return to activity, followed by the combination of number and duration of anhydrobiosis episodes, influence of the presence of other individuals, and sex. More individuals returned to activity after repeated short than repeated long anhydrobiosis episodes and older individuals were less likely to recover than younger individuals. In addition, when compared to single animals, the presence of other individuals resulted in higher number of active animals after dehydration and rehydration. The effect of sex was significant, but there was no general tendency for one sex to recover from anhydrobiosis better than the other one. The results contribute to a better understanding of the anhydrobiosis ability of Paramacrobiotus experimentalis and provide background for full explanation of molecular, cellular and environmental mechanisms of anhydrobiosis.
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Affiliation(s)
- Amit Kumar Nagwani
- Department of Bioenergetics, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University in Poznań, Poland
| | - Iwona Melosik
- Department of Genetics, Institute of Experimental Biology, Faculty of Biology, Adam Mickiewicz University in Poznań, Poland
| | - Łukasz Kaczmarek
- Department of Animal Taxonomy and Ecology, Institute of Environmental Biology, Faculty of Biology, Adam Mickiewicz University in Poznań, Poland
| | - Hanna Kmita
- Department of Bioenergetics, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University in Poznań, Poland
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2
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Vecchi M, Stec D, Rebecchi L, Michalczyk Ł, Calhim S. Ecology explains anhydrobiotic performance across tardigrades, but the shared evolutionary history matters more. J Anim Ecol 2024; 93:307-318. [PMID: 37994566 DOI: 10.1111/1365-2656.14031] [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: 06/21/2023] [Accepted: 10/21/2023] [Indexed: 11/24/2023]
Abstract
Desiccation stress is lethal to most animals. However, some microinvertebrate groups have evolved coping strategies, such as the ability to undergo anhydrobiosis (i.e. survival despite the loss of almost all body water). Tardigrades are one such group, where the molecular mechanisms of anhydrobiosis have been more thoroughly studied. Despite the ecological, evolutionary and biotechnological importance of anhydrobiosis, little is known about its inter- and intra-specific variability nor its relationship with natural habitat conditions or phylogenetic history. We developed a new index-anhydrobiotic recovery index (ARI)-to evaluate the anhydrobiotic performance of tardigrade populations from the family Macrobiotidae. Moreover, we compared the explanatory role of habitat humidity and phylogenetic history on this trait using a variance partitioning approach. We found that ARI is correlated with both microhabitat humidity and yearly rainfall, but it is mostly driven by phylogenetic niche conservatism (i.e. a high portion of ARI variation is explained by phylogeny alone). Finally, we showed that anhydrobiotic performance is highly variable, even between closely related species, and that their response to local ecological conditions is tightly linked to their phylogenetic history. This study not only presents key insights into an emerging model system, but also provides a new methodological approach for wider scale studies of the ecological and evolutionary implications of anhydrobiosis.
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Affiliation(s)
- M Vecchi
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
- Institute of Systematics and Evolution of Animals, Polish Academy of Sciences, Kraków, Poland
| | - D Stec
- Institute of Systematics and Evolution of Animals, Polish Academy of Sciences, Kraków, Poland
| | - L Rebecchi
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
- National Biodiversity Future Center (NBFC), Palermo, Italy
| | - Ł Michalczyk
- Department of Invertebrate Evolution, Faculty of Biology, Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków, Poland
| | - S Calhim
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
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3
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Kayastha P, Wieczorkiewicz F, Pujol M, Robinson A, Michalak M, Kaczmarek Ł, Poprawa I. Elevated external temperature affects cell ultrastructure and heat shock proteins (HSPs) in Paramacrobiotus experimentalis Kaczmarek, Mioduchowska, Poprawa, & Roszkowska, 2020. Sci Rep 2024; 14:5097. [PMID: 38429316 PMCID: PMC10907573 DOI: 10.1038/s41598-024-55295-z] [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: 07/25/2023] [Accepted: 02/22/2024] [Indexed: 03/03/2024] Open
Abstract
Increasing temperature influences the habitats of various organisms, including microscopic invertebrates. To gain insight into temperature-dependent changes in tardigrades, we isolated storage cells exposed to various temperatures and conducted biochemical and ultrastructural analysis in active and tun-state Paramacrobiotus experimentalis Kaczmarek, Mioduchowska, Poprawa, & Roszkowska, 2020. The abundance of heat shock proteins (HSPs) and ultrastructure of the storage cells were examined at different temperatures (20 °C, 30 °C, 35 °C, 37 °C, 40 °C, and 42 °C) in storage cells isolated from active specimens of Pam. experimentalis. In the active animals, upon increase in external temperature, we observed an increase in the levels of HSPs (HSP27, HSP60, and HSP70). Furthermore, the number of ultrastructural changes in storage cells increased with increasing temperature. Cellular organelles, such as mitochondria and the rough endoplasmic reticulum, gradually degenerated. At 42 °C, cell death occurred by necrosis. Apart from the higher electron density of the karyoplasm and the accumulation of electron-dense material in some mitochondria (at 42 °C), almost no changes were observed in the ultrastructure of tun storage cells exposed to different temperatures. We concluded that desiccated (tun-state) are resistant to high temperatures, but not active tardigrades (survival rates of tuns after 24 h of rehydration: 93.3% at 20 °C, 60.0% at 35 °C, 33.3% at 37 °C, 33.3% at 40 °C, and 20.0% at 42 °C).
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Affiliation(s)
- Pushpalata Kayastha
- Department of Animal Taxonomy and Ecology, Faculty of Biology, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego 6, 61-614, Poznań, Poland.
| | - Filip Wieczorkiewicz
- Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia in Katowice, Bankowa 9, 40-007, Katowice, Poland
| | - Myriam Pujol
- Department of Biochemistry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Alison Robinson
- Department of Biochemistry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Marek Michalak
- Department of Biochemistry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Łukasz Kaczmarek
- Department of Animal Taxonomy and Ecology, Faculty of Biology, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego 6, 61-614, Poznań, Poland
| | - Izabela Poprawa
- Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia in Katowice, Bankowa 9, 40-007, Katowice, Poland.
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4
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Hvidepil LKB, Møbjerg N. New insights into osmobiosis and chemobiosis in tardigrades. Front Physiol 2023; 14:1274522. [PMID: 37929212 PMCID: PMC10620314 DOI: 10.3389/fphys.2023.1274522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 10/02/2023] [Indexed: 11/07/2023] Open
Abstract
Tardigrades are renowned for their ability to enter the extremotolerant state of latent life known as cryptobiosis. While it is widely accepted that cryptobiosis can be induced by freezing (cryobiosis) and by desiccation (anhydrobiosis), the latter involving formation of a so-called tun, the exact mechanisms underlying the state-as well as the significance of other cryptobiosis inducing factors-remain ambiguous. Here, we focus on osmotic and chemical stress tolerance in the marine tidal tardigrade Echiniscoides sigismundi. We show that E. sigismundi enters the tun state following exposure to saturated seawater and upon exposure to locality seawater containing the mitochondrial uncoupler DNP. The latter experiments provide evidence of osmobiosis and chemobiosis, i.e., cryptobiosis induced by high levels of osmolytes and toxicants, respectively. A small decrease in survival was observed following simultaneous exposure to DNP and saturated seawater indicating that the tardigrades may not be entirely ametabolic while in the osmobiotic tun. The tardigrades easily handle exposure to ultrapure water, but hypo-osmotic shock impairs tun formation and when exposed to ultrapure water the tardigrades do not tolerate DNP, indicating that tolerance towards dilute solutions involves energy-consuming processes. We discuss our data in relation to earlier and more contemporary studies on cryptobiosis and we argue that osmobiosis should be defined as a state of cryptobiosis induced by high external osmotic pressure. Our investigation supports the hypothesis that the mechanisms underlying osmobiosis and anhydrobiosis are overlapping and that osmobiosis likely represents the evolutionary forerunner of cryptobiosis forms that involve body water deprivation.
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Affiliation(s)
| | - Nadja Møbjerg
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
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5
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Roszkowska M, Gołdyn B, Wojciechowska D, Księżkiewicz Z, Fiałkowska E, Pluskota M, Kmita H, Kaczmarek Ł. How long can tardigrades survive in the anhydrobiotic state? A search for tardigrade anhydrobiosis patterns. PLoS One 2023; 18:e0270386. [PMID: 36630322 PMCID: PMC9833599 DOI: 10.1371/journal.pone.0270386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 12/12/2022] [Indexed: 01/12/2023] Open
Abstract
Anhydrobiosis is a desiccation tolerance that denotes the ability to survive almost complete dehydration without sustaining damage. The knowledge on the survival capacity of various tardigrade species in anhydrobiosis is still very limited. Our research compares anhydrobiotic capacities of four tardigrade species from different genera, i.e. Echiniscus testudo, Paramacrobiotus experimentalis, Pseudohexapodibius degenerans and Macrobiotus pseudohufelandi, whose feeding behavior and occupied habitats are different. Additionally, in the case of Ech. testudo, we analyzed two populations: one urban and one from a natural habitat. The observed tardigrade species displayed clear differences in their anhydrobiotic capacity, which appear to be determined by the habitat rather than nutritional behavior of species sharing the same habitat type. The results also indicate that the longer the state of anhydrobiosis lasts, the more time the animals need to return to activity.
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Affiliation(s)
- Milena Roszkowska
- Faculty of Biology, Department of Animal Taxonomy and Ecology, Adam Mickiewicz University, Poznań, Poland
- Faculty of Biology, Department of Bioenergetics, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznań, Poland
| | - Bartłomiej Gołdyn
- Faculty of Biology, Department of General Zoology, Adam Mickiewicz University, Poznań, Poland
| | - Daria Wojciechowska
- Faculty of Physics, Department of Biomedical Physics, Adam Mickiewicz University, Poznań, Poland
| | - Zofia Księżkiewicz
- Faculty of Biology, Department of General Zoology, Adam Mickiewicz University, Poznań, Poland
| | - Edyta Fiałkowska
- Institute of Environmental Sciences, Jagiellonian University, Kraków, Poland
| | - Mateusz Pluskota
- Faculty of Biology, Department of General Zoology, Adam Mickiewicz University, Poznań, Poland
| | - Hanna Kmita
- Faculty of Biology, Department of Bioenergetics, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznań, Poland
| | - Łukasz Kaczmarek
- Faculty of Biology, Department of Animal Taxonomy and Ecology, Adam Mickiewicz University, Poznań, Poland
- * E-mail:
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6
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Sieger J, Brümmer F, Ahn H, Lee G, Kim S, Schill RO. Reduced ageing in the frozen state in the tardigrade
Milnesium inceptum
(Eutardigrada: Apochela). J Zool (1987) 2022. [DOI: 10.1111/jzo.13018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- J. Sieger
- Institute of Biomaterials and Biomolecular Systems, University of Stuttgart Stuttgart Germany
| | - F. Brümmer
- Institute of Biomaterials and Biomolecular Systems, University of Stuttgart Stuttgart Germany
| | - H. Ahn
- Department of Life Sciences Pohang University of Science and Technology Pohang South Korea
| | - G. Lee
- Department of Life Sciences Pohang University of Science and Technology Pohang South Korea
| | - S. Kim
- Department of Life Sciences Pohang University of Science and Technology Pohang South Korea
| | - R. O. Schill
- Institute of Biomaterials and Biomolecular Systems, University of Stuttgart Stuttgart Germany
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7
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Poprawa I, Bartylak T, Kulpla A, Erdmann W, Roszkowska M, Chajec Ł, Kaczmarek Ł, Karachitos A, Kmita H. Verification of Hypsibius exemplaris Gąsiorek et al., 2018 (Eutardigrada; Hypsibiidae) application in anhydrobiosis research. PLoS One 2022; 17:e0261485. [PMID: 35303010 PMCID: PMC8932574 DOI: 10.1371/journal.pone.0261485] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Accepted: 02/25/2022] [Indexed: 01/03/2023] Open
Abstract
Anhydrobiosis is considered to be an adaptation of important applicative implications because it enables resistance to the lack of water. The phenomenon is still not well understood at molecular level. Thus, a good model invertebrate species for the research is required. The best known anhydrobiotic invertebrates are tardigrades (Tardigrada), considered to be toughest animals in the world. Hypsibius. exemplaris is one of the best studied tardigrade species, with its name "exemplaris" referring to the widespread use of the species as a laboratory model for various types of research. However, available data suggest that anhydrobiotic capability of the species may be overestimated. Therefore, we determined anhydrobiosis survival by Hys. exemplaris specimens using three different anhydrobiosis protocols. We also checked ultrastructure of storage cells within formed dormant structures (tuns) that has not been studied yet for Hys. exemplaris. These cells are known to support energetic requirements of anhydrobiosis. The obtained results indicate that Hys. exemplaris appears not to be a good model species for anhydrobiosis research.
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Affiliation(s)
- Izabela Poprawa
- Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia in Katowice, Bankowa, Katowice, Poland
| | - Tomasz Bartylak
- Department of Animal Taxonomy and Ecology, Faculty of Biology, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego, Poznań, Poland
- Department of Bioenergetics, Faculty of Biology, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego, Poznań, Poland
| | - Adam Kulpla
- Center for Advanced Technology, Adam Mickiewicz University, Uniwersytetu Poznańskiego, Poznań, Poland
- Faculty of Biology, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego, Poznań, Poland
| | - Weronika Erdmann
- Department of Animal Taxonomy and Ecology, Faculty of Biology, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego, Poznań, Poland
| | - Milena Roszkowska
- Department of Bioenergetics, Faculty of Biology, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego, Poznań, Poland
| | - Łukasz Chajec
- Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia in Katowice, Bankowa, Katowice, Poland
| | - Łukasz Kaczmarek
- Department of Animal Taxonomy and Ecology, Faculty of Biology, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego, Poznań, Poland
| | - Andonis Karachitos
- Department of Bioenergetics, Faculty of Biology, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego, Poznań, Poland
| | - Hanna Kmita
- Department of Bioenergetics, Faculty of Biology, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego, Poznań, Poland
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8
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Giovannini I, Boothby TC, Cesari M, Goldstein B, Guidetti R, Rebecchi L. Production of reactive oxygen species and involvement of bioprotectants during anhydrobiosis in the tardigrade Paramacrobiotus spatialis. Sci Rep 2022; 12:1938. [PMID: 35121798 PMCID: PMC8816950 DOI: 10.1038/s41598-022-05734-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 12/06/2021] [Indexed: 12/30/2022] Open
Abstract
Water unavailability is an abiotic stress causing unfavourable conditions for life. Nevertheless, some animals evolved anhydrobiosis, a strategy allowing for the reversible organism dehydration and suspension of metabolism as a direct response to habitat desiccation. Anhydrobiotic animals undergo biochemical changes synthesizing bioprotectants to help combat desiccation stresses. One stress is the generation of reactive oxygen species (ROS). In this study, the eutardigrade Paramacrobiotus spatialis was used to investigate the occurrence of ROS associated with the desiccation process. We observed that the production of ROS significantly increases as a function of time spent in anhydrobiosis and represents a direct demonstration of oxidative stress in tardigrades. The degree of involvement of bioprotectants, including those combating ROS, in the P. spatialis was evaluated by perturbing their gene functions using RNA interference and assessing the successful recovery of animals after desiccation/rehydration. Targeting the glutathione peroxidase gene compromised survival during drying and rehydration, providing evidence for the role of the gene in desiccation tolerance. Targeting genes encoding glutathione reductase and catalase indicated that these molecules play roles during rehydration. Our study also confirms the involvement of aquaporins 3 and 10 during rehydration. Therefore, desiccation tolerance depends on the synergistic action of many different molecules working together.
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Affiliation(s)
- Ilaria Giovannini
- Department of Life Sciences, University of Modena and Reggio Emilia, Via G. Campi 213/D, 41125, Modena, Italy.
| | - Thomas C Boothby
- Department of Molecular Biology, University of Wyoming, Laramie, WY, USA.,Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Michele Cesari
- Department of Life Sciences, University of Modena and Reggio Emilia, Via G. Campi 213/D, 41125, Modena, Italy
| | - Bob Goldstein
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Roberto Guidetti
- Department of Life Sciences, University of Modena and Reggio Emilia, Via G. Campi 213/D, 41125, Modena, Italy
| | - Lorena Rebecchi
- Department of Life Sciences, University of Modena and Reggio Emilia, Via G. Campi 213/D, 41125, Modena, Italy
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9
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Wojciechowska D, Karachitos A, Roszkowska M, Rzeźniczak W, Sobkowiak R, Kaczmarek Ł, Kosicki JZ, Kmita H. Mitochondrial alternative oxidase contributes to successful tardigrade anhydrobiosis. Front Zool 2021; 18:15. [PMID: 33794934 PMCID: PMC8015188 DOI: 10.1186/s12983-021-00400-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 03/15/2021] [Indexed: 12/14/2022] Open
Abstract
Anhydrobiosis can be described as an adaptation to lack of water that enables some organisms, including tardigrades, to survive extreme conditions, even some that do not exist on Earth. The cellular mechanisms underlying anhydrobiosis are still not completely explained including the putative contribution of mitochondrial proteins. Since mitochondrial alternative oxidase (AOX), described as a drought response element in plants, was recently proposed for various invertebrates including tardigrades, we investigated whether AOX is involved in successful anhydrobiosis of tardigrades. Milnesium inceptum was used as a model for the study. We confirmed functionality of M. inceptum AOX and estimated its contribution to the tardigrade revival after anhydrobiosis of different durations. We observed that AOX activity was particularly important for M. inceptum revival after the long-term tun stage but did not affect the rehydration stage specifically. The results may contribute to our understanding and then application of anhydrobiosis underlying mechanisms.
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Affiliation(s)
- Daria Wojciechowska
- Department of Macromolecular Physics, Faculty of Physics, Adam Mickiewicz University, Poznań, Poland.,Department of Bioenergetics, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland
| | - Andonis Karachitos
- Department of Bioenergetics, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland
| | - Milena Roszkowska
- Department of Bioenergetics, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland.,Department of Animal Taxonomy and Ecology, Institute of Environmental Biology, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland
| | - Wiktor Rzeźniczak
- Department of Bioenergetics, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland
| | - Robert Sobkowiak
- Department of Cell Biology, Institute of Experimental Biology, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland
| | - Łukasz Kaczmarek
- Department of Animal Taxonomy and Ecology, Institute of Environmental Biology, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland
| | - Jakub Z Kosicki
- Department of Avian Biology and Ecology, Institute of Experimental Biology, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland
| | - Hanna Kmita
- Department of Bioenergetics, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland.
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10
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Thermotolerance experiments on active and desiccated states of Ramazzottius varieornatus emphasize that tardigrades are sensitive to high temperatures. Sci Rep 2020; 10:94. [PMID: 31919388 PMCID: PMC6952461 DOI: 10.1038/s41598-019-56965-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 12/19/2019] [Indexed: 11/09/2022] Open
Abstract
Global warming is already having harmful effects on habitats worldwide and it is therefore important to gain an understanding of how rising temperatures may affect extant animals. Here, we investigate the tolerance to high temperatures of Ramazzottius varieornatus, a tardigrade frequently found in transient freshwater habitats. Using logistic modelling on activity we evaluate the effect of 24 hour temperature exposures on active tardigrades, with or without a short acclimation period, compared to exposures of desiccated tardigrades. We estimate that the 50% mortality temperature for non-acclimated active tardigrades is 37.1 °C, with a small but significant increase to 37.6 °C following acclimation. Desiccated specimens tolerate much higher temperatures, with an estimated 50% mortality temperature of 82.7 °C following 1 hour exposures, but with a significant decrease to 63.1 °C following 24 hour exposures. Our results show that metabolically active tardigrades are vulnerable to high temperatures, yet acclimatization could provide a tolerance increase. Desiccated specimens show a much higher resilience—exposure-time is, however, a limiting factor giving tardigrades a restricted window of high temperature tolerance. Tardigrades are renowned for their ability to tolerate extreme conditions, but their endurance towards high temperatures clearly has an upper limit—high temperatures thus seem to be their Achilles heel.
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11
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Jönsson KI. Radiation Tolerance in Tardigrades: Current Knowledge and Potential Applications in Medicine. Cancers (Basel) 2019; 11:E1333. [PMID: 31505739 PMCID: PMC6770827 DOI: 10.3390/cancers11091333] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 09/04/2019] [Accepted: 09/06/2019] [Indexed: 11/17/2022] Open
Abstract
Tardigrades represent a phylum of very small aquatic animals in which many species have evolved adaptations to survive under extreme environmental conditions, such as desiccation and freezing. Studies on several species have documented that tardigrades also belong to the most radiation-tolerant animals on Earth. This paper gives an overview of our current knowledge on radiation tolerance of tardigrades, with respect to dose-responses, developmental stages, and different radiation sources. The molecular mechanisms behind radiation tolerance in tardigrades are still largely unknown, but omics studies suggest that both mechanisms related to the avoidance of DNA damage and mechanisms of DNA repair are involved. The potential of tardigrades to provide knowledge of importance for medical sciences has long been recognized, but it is not until recently that more apparent evidence of such potential has appeared. Recent studies show that stress-related tardigrade genes may be transfected to human cells and provide increased tolerance to osmotic stress and ionizing radiation. With the recent sequencing of the tardigrade genome, more studies applying tardigrade omics to relevant aspects of human medicine are expected. In particular, the cancer research field has potential to learn from studies on tardigrades about molecular mechanisms evolved to maintain genome integrity.
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Affiliation(s)
- K Ingemar Jönsson
- Department of Environmental Science and Bioscience, Kristianstad University, 291 88 Kristianstad, Sweden.
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12
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13
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Jönsson KI, Holm I, Tassidis H. Cell Biology of the Tardigrades: Current Knowledge and Perspectives. Results Probl Cell Differ 2019; 68:231-249. [PMID: 31598859 DOI: 10.1007/978-3-030-23459-1_10] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The invertebrate phylum Tardigrada has received much attention for containing species adapted to the most challenging environmental conditions where an ability to survive complete desiccation or freezing in a cryptobiotic state is necessary for persistence. Although research on tardigrades has a long history, the last decade has seen a dramatic increase in molecular biological ("omics") studies, most of them with the aim to reveal the biochemical mechanisms behind desiccation tolerance of tardigrades. Several other aspects of tardigrade cell biology have been studied, and we review some of them, including karyology, embryology, the role of storage cells, and the question of whether tardigrades are eutelic animals. We also review some of the theories about how anhydrobiotic organisms are able to maintain cell integrity under dry conditions, and our current knowledge on the role of vitrification and DNA protection and repair. Many aspects of tardigrade stress tolerance have relevance for human medicine, and the first transfers of tardigrade stress genes to human cells have now appeared. We expect this field to develop rapidly in the coming years, as more genomic information becomes available. However, many basic cell biological aspects remain to be investigated, such as immunology, cell cycle kinetics, cell metabolism, and culturing of tardigrade cells. Such development will be necessary to allow tardigrades to move from a nonmodel organism position to a true model organism with interesting associations with the current models C. elegans and D. melanogaster.
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Affiliation(s)
- K Ingemar Jönsson
- Department of Environmental Science and Bioscience, Kristianstad University, Kristianstad, Sweden.
| | - Ingvar Holm
- Department of Environmental Science and Bioscience, Kristianstad University, Kristianstad, Sweden
| | - Helena Tassidis
- Department of Environmental Science and Bioscience, Kristianstad University, Kristianstad, Sweden
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Gross V, Müller M, Hehn L, Ferstl S, Allner S, Dierolf M, Achterhold K, Mayer G, Pfeiffer F. X-ray imaging of a water bear offers a new look at tardigrade internal anatomy. ZOOLOGICAL LETTERS 2019; 5:14. [PMID: 31110777 PMCID: PMC6511223 DOI: 10.1186/s40851-019-0130-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 04/09/2019] [Indexed: 05/03/2023]
Abstract
BACKGROUND Tardigrades (water bears) are microscopic invertebrates of which the anatomy has been well studied using traditional techniques, but a comprehensive three-dimensional reconstruction has never been performed. In order to close this gap, we employed X-ray computed tomography (CT), a technique that is becoming increasingly popular in zoology for producing high-resolution, three-dimensional (3D) scans of whole specimens. While CT has long been used to scan larger samples, its use in some microscopic animals can be problematic, as they are often too small for conventional CT yet too large for high-resolution, optics-based soft X-ray microscopy. This size gap continues to be narrowed with advancements in technology, with high-resolution imaging now being possible using both large synchrotron devices and, more recently, laboratory-based instruments. RESULTS Here we use a recently developed prototype lab-based nano-computed tomography device to image a 152 μm-long tardigrade at high resolution (200-270 nm pixel size). The resulting dataset allowed us to visualize the anatomy of the tardigrade in 3D and analyze the spatial relationships of the internal structures. Segmentation of the major structures of the body enabled the direct measurement of their respective volumes. Furthermore, we segmented every storage cell individually and quantified their volume distribution. We compare our measurements to those from published studies in which other techniques were used. CONCLUSIONS The data presented herein demonstrate the utility of CT imaging as a powerful supplementary tool for studies of tardigrade anatomy, especially for quantitative volume measurements. This nanoCT study represents the smallest complete animal ever imaged using CT, and offers new 3D insights into the spatial relationships of the internal organs of water bears.
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Affiliation(s)
- Vladimir Gross
- Department of Zoology, Institute of Biology, University of Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany
| | - Mark Müller
- Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748 Garching, Germany
| | - Lorenz Hehn
- Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748 Garching, Germany
| | - Simone Ferstl
- Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748 Garching, Germany
| | - Sebastian Allner
- Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748 Garching, Germany
| | - Martin Dierolf
- Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748 Garching, Germany
| | - Klaus Achterhold
- Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748 Garching, Germany
| | - Georg Mayer
- Department of Zoology, Institute of Biology, University of Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany
| | - Franz Pfeiffer
- Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748 Garching, Germany
- Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany
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15
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Czerneková M, Janelt K, Student S, Jönsson KI, Poprawa I. A comparative ultrastructure study of storage cells in the eutardigrade Richtersius coronifer in the hydrated state and after desiccation and heating stress. PLoS One 2018; 13:e0201430. [PMID: 30096140 PMCID: PMC6086413 DOI: 10.1371/journal.pone.0201430] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 07/16/2018] [Indexed: 02/03/2023] Open
Abstract
Tardigrades represent an invertebrate phylum with no circulatory or respiratory system. Their body cavity is filled with free storage cells of the coelomocyte-type, which are responsible for important physiological functions. We report a study comparing the ultrastructure of storage cells in anhydrobiotic and hydrated specimens of the eutardigrade Richtersius coronifer. We also analysed the effect of temperature stress on storage cell structure. Firstly, we verified two types of ultrastructurally different storage cells, which differ in cellular organelle complexity, amount and content of reserve material and connection to oogenetic stage. Type I cells were found to differ ultrastructurally depending on the oogenetic stage of the animal. The main function of these cells is energy storage. Storage cells of Type I were also observed in the single male that was found among the analysed specimens. The second cell type, Type II, found only in females, represents young undifferentiated cells, possibly stem cells. The two types of cells also differ with respect to the presence of nucleolar vacuoles, which are related to oogenetic stages and to changes in nucleolic activity during oogenesis. Secondly, this study revealed that storage cells are not ultrastructurally affected by six months of desiccation or by heating following this desiccation period. However, heating of the desiccated animals (tuns) tended to reduce animal survival, indicating that long-term desiccation makes these animals more vulnerable to heat stress. We confirmed the degradative pathways during the rehydration process after desiccation and heat stress. Our study is the first to document two ultrastructurally different types of storage cells in tardigrades and reveals new perspectives for further studies of tardigrade storage cells.
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Affiliation(s)
- Michaela Czerneková
- Department of Environmental Science and Bioscience, Kristianstad University, Kristianstad, Sweden
- Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
- Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Kamil Janelt
- Department of Animal Histology and Embryology, University of Silesia in Katowice, Katowice, Poland
| | - Sebastian Student
- Silesian University of Technology, Institute of Automatic Control, Gliwice, Poland
| | - K. Ingemar Jönsson
- Department of Environmental Science and Bioscience, Kristianstad University, Kristianstad, Sweden
| | - Izabela Poprawa
- Department of Animal Histology and Embryology, University of Silesia in Katowice, Katowice, Poland
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16
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Sørensen-Hygum TL, Stuart RM, Jørgensen A, Møbjerg N. Modelling extreme desiccation tolerance in a marine tardigrade. Sci Rep 2018; 8:11495. [PMID: 30065347 PMCID: PMC6068186 DOI: 10.1038/s41598-018-29824-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 07/18/2018] [Indexed: 11/17/2022] Open
Abstract
It has recently been argued that the enigmatic tardigrades (water bears) will endure until the sun dies, surviving any astrophysical calamities in Earth's oceans. Yet, our knowledge of stress tolerance among marine tardigrade species is very limited and most investigations revolve around species living in moist habitats on land. Here, we investigate desiccation tolerance in the cosmopolitan marine tidal tardigrade, Echiniscoides sigismundi, providing the first thorough analysis on recovery upon desiccation from seawater. We test the influence on survival of desiccation surface, time spent desiccated (up to 1 year) and initial water volume. We propose analysis methods for survival estimates, which can be used as a future platform for evaluating and analysing recovery rates in organisms subjected to extreme stress. Our data reveal that marine tidal tardigrades tolerate extremely rapid and extended periods of desiccation from seawater supporting the argument that these animals are among the toughest organisms on Earth.
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Affiliation(s)
- Thomas L Sørensen-Hygum
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Robyn M Stuart
- Data Science Laboratory, Department of Mathematical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Aslak Jørgensen
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Nadja Møbjerg
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
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17
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Hygum TL, Clausen LKB, Halberg KA, Jørgensen A, Møbjerg N. Tun formation is not a prerequisite for desiccation tolerance in the marine tidal tardigradeEchiniscoides sigismundi. Zool J Linn Soc 2016. [DOI: 10.1111/zoj.12444] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Thomas L. Hygum
- Department of Biology; University of Copenhagen; August Krogh Building, Universitetsparken 13 Copenhagen Denmark
| | - Lykke K. B. Clausen
- Department of Biology; University of Copenhagen; August Krogh Building, Universitetsparken 13 Copenhagen Denmark
| | - Kenneth A. Halberg
- Department of Biology; University of Copenhagen; August Krogh Building, Universitetsparken 13 Copenhagen Denmark
- Institute of Molecular, Cell and Systems Biology; College of Medical, Veterinary and Life Sciences, University of Glasgow; Davidson Building Room 324 Glasgow G12 8QQ UK
| | - Aslak Jørgensen
- Department of Biology; University of Copenhagen; August Krogh Building, Universitetsparken 13 Copenhagen Denmark
| | - Nadja Møbjerg
- Department of Biology; University of Copenhagen; August Krogh Building, Universitetsparken 13 Copenhagen Denmark
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18
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Czernekova M, Jönsson KI. Mitosis in storage cells of the eutardigradeRichtersius coronifer. Zool J Linn Soc 2016. [DOI: 10.1111/zoj.12440] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Michaela Czernekova
- School of Education and Environment; Kristianstad University; Kristianstad Sweden
- Institute of Physiology; Academy of Sciences of the Czech Republic; Prague Czech Republic
- Faculty of Medicine; Charles University; Prague Czech Republic
| | - K. Ingemar Jönsson
- School of Education and Environment; Kristianstad University; Kristianstad Sweden
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19
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Hyra M, Rost-Roszkowska MM, Student S, Włodarczyk A, Deperas M, Janelt K, Poprawa I. Body cavity cells of Parachela during their active life. Zool J Linn Soc 2016. [DOI: 10.1111/zoj.12463] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Marta Hyra
- Department of Animal Histology and Embryology; University of Silesia; Bankowa 9 Katowice 40-007 Poland
| | | | - Sebastian Student
- Institute of Automatic Control; Silesian University of Technology; Akademicka 16 Gliwice 44-100 Poland
| | - Agnieszka Włodarczyk
- Department of Animal Histology and Embryology; University of Silesia; Bankowa 9 Katowice 40-007 Poland
| | - Marcin Deperas
- Department of Animal Histology and Embryology; University of Silesia; Bankowa 9 Katowice 40-007 Poland
| | - Kamil Janelt
- Department of Animal Histology and Embryology; University of Silesia; Bankowa 9 Katowice 40-007 Poland
| | - Izabela Poprawa
- Department of Animal Histology and Embryology; University of Silesia; Bankowa 9 Katowice 40-007 Poland
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20
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Czernekova M, Jönsson KI. Experimentally Induced Repeated Anhydrobiosis in the Eutardigrade Richtersius coronifer. PLoS One 2016; 11:e0164062. [PMID: 27828978 PMCID: PMC5102368 DOI: 10.1371/journal.pone.0164062] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 09/19/2016] [Indexed: 11/19/2022] Open
Abstract
Tardigrades represent one of the main animal groups with anhydrobiotic capacity at any stage of their life cycle. The ability of tardigrades to survive repeated cycles of anhydrobiosis has rarely been studied but is of interest to understand the factors constraining anhydrobiotic survival. The main objective of this study was to investigate the patterns of survival of the eutardigrade Richtersius coronifer under repeated cycles of desiccation, and the potential effect of repeated desiccation on size, shape and number of storage cells. We also analyzed potential change in body size, gut content and frequency of mitotic storage cells. Specimens were kept under non-cultured conditions and desiccated under controlled relative humidity. After each desiccation cycle 10 specimens were selected for analysis of morphometric characteristics and mitosis. The study demonstrates that tardigrades may survive up to 6 repeated desiccations, with declining survival rates with increased number of desiccations. We found a significantly higher proportion of animals that were unable to contract properly into a tun stage during the desiccation process at the 5th and 6th desiccations. Also total number of storage cells declined at the 5th and 6th desiccations, while no effect on storage cell size was observed. The frequency of mitotic storage cells tended to decline with higher number of desiccation cycles. Our study shows that the number of consecutive cycles of anhydrobiosis that R. coronifer may undergo is limited, with increased inability for tun formation and energetic constraints as possible causal factors.
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Affiliation(s)
- Michaela Czernekova
- School of Education and Environment, Kristianstad University, Kristianstad, Sweden
- Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
- Faculty of Medicine, Charles University, Prague, Czech Republic
- * E-mail:
| | - K. Ingemar Jönsson
- School of Education and Environment, Kristianstad University, Kristianstad, Sweden
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21
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Wełnicz W, Grohme MA, Kaczmarek L, Schill RO, Frohme M. Anhydrobiosis in tardigrades--the last decade. JOURNAL OF INSECT PHYSIOLOGY 2011; 57:577-583. [PMID: 21440551 DOI: 10.1016/j.jinsphys.2011.03.019] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Revised: 03/15/2011] [Accepted: 03/16/2011] [Indexed: 05/30/2023]
Abstract
The current state of knowledge about anhydrobiosis in tardigrades is presented. In response to adverse environmental conditions tardigrades arrest their metabolic activity and after complete dehydration enter the so-called "tun" state. In this ametabolic state they are able to tolerate exposure to various chemical and physical extremes. These micrometazoans have evolved various kinds of morphological, physiological and molecular adaptations to reduce the effects of desiccation. In this review we address behavioral adaptation, morphological features and molecules which determine the anhydrobiotic survival. The influence of the time spent in anhydrobiotic state on the lifespan and DNA and the role of the antioxidant defense system are also considered. Finally we summarize recent input from the "omics" sciences.
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Affiliation(s)
- Weronika Wełnicz
- Molecular Biology and Functional Genome Analysis, University of Applied Sciences Wildau, Germany.
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22
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Nilsson EJC, Jönsson KI, Pallon J. Tolerance to proton irradiation in the eutardigrade Richtersius coronifer--a nuclear microprobe study. Int J Radiat Biol 2010; 86:420-7. [PMID: 20397847 DOI: 10.3109/09553000903568001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE The tardigrade Richtersius coronifer has previously been shown to tolerate very high doses of low linear energy transfer (low-LET) radiation (gamma rays). The purpose of this study was to extend our knowledge on radiation tolerance in this species by investigating the dose-response to high-LET radiation in terms of protons. MATERIALS AND METHODS Dehydrated tardigrades of the species R. coronifer were irradiated with 2.55 MeV (megaelectronvolts) protons at doses ranging from 500 gray (Gy) to 15,000 Gy, to investigate the dose-viability relationship. In addition, a focused proton microbeam was utilised to determine the areal mass distribution, using the ion beam analytical technique STIM (Scanning Transmission Ion Microscopy). RESULTS The experiment suggests that R. coronifer is unaffected by doses of proton irradiation up to 10,000 Gy, but shows very little viability at higher doses. The STIM analysis revealed that the thickness of the dehydrated tardigrades exceeds 150 microm, and that a fraction of the protons may not be fully absorbed. CONCLUSION Our results are in line with previous studies of exposure to high-LET radiation in tardigrades, indicating that these animals are equally or even more tolerant to high-LET compared to low-LET gamma radiation. The physiological background to this remarkable result is currently unknown, but deserves investigation.
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23
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Faurby S, Jönsson KI, Rebecchi L, Funch P. Variation in anhydrobiotic survival of two eutardigrade morphospecies: a story of cryptic species and their dispersal. J Zool (1987) 2008. [DOI: 10.1111/j.1469-7998.2008.00420.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Jönsson KI, Schill RO. Induction of Hsp70 by desiccation, ionising radiation and heat-shock in the eutardigrade Richtersius coronifer. Comp Biochem Physiol B Biochem Mol Biol 2007; 146:456-60. [PMID: 17261378 DOI: 10.1016/j.cbpb.2006.10.111] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2006] [Revised: 09/18/2006] [Accepted: 10/21/2006] [Indexed: 10/23/2022]
Abstract
The physiology and biochemistry behind the extreme tolerance to desiccation shown by the so-called anhydrobiotic animals represents an exciting challenge to biology. The current knowledge suggests that both carbohydrates and proteins are often involved in protecting the dry cell from damage, or in the repair of induced damage. Tardigrades belong to the most desiccation-tolerant multicellular organisms, but very little research has been reported on the biochemistry behind desiccation tolerance in this group. We quantified the induction of the heat-shock protein Hsp70, a very wide-spread stress protein, in response to desiccation, ionising radiation, and heating, in the anhydrobiotic tardigrade Richtersius coronifer using an immuno-westernblot method. Elevated levels of Hsp70 were recorded after treatment of both heat and ionising radiation, and also in rehydrated tardigrades after a period of desiccation. In contrast, tardigrades in the desiccated (dry) state had reduced Hsp70 levels compared to the non-treated control group. Our results suggest that Hsp70 may be involved in the physiological and biochemical system underlying desiccation (and radiation) tolerance in tardigrades, and that its role may be connected to repair processes after desiccation rather than to biochemical stabilization in the dry state.
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Affiliation(s)
- K Ingemar Jönsson
- Department of Mathematics and Natural Science, Kristianstad University, S-291 88 Kristianstad, Sweden.
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25
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Jönsson KI, Harms-Ringdahl M, Torudd J. Radiation tolerance in the eutardigrade Richtersius coronifer. Int J Radiat Biol 2006; 81:649-56. [PMID: 16368643 DOI: 10.1080/09553000500368453] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
PURPOSE Tardigrades have a reputation of being extremely tolerant to extreme environmental conditions including tolerance to ionizing radiation while in a desiccated, anhydrobiotic state. However, the evidence for radio-tolerance in tardigrades is based on only one previous report, and there is an obvious need for complementary studies. In this paper we report an investigation on radio-tolerance in desiccated and hydrated specimens of the eutardigrade Richtersius coronifer. MATERIALS AND METHODS Groups of 30 - 50 tardigrades were exposed to gamma-radiation at doses between 1.0 - 9.0 (anhydrobiotic animals) or 0.5 - 5.0 (hydrated animals) kGy and the animals were followed until all were dead. Radiation tolerance of both desiccated and hydrated tardigrades was studied. RESULTS Both desiccated and hydrated animals irradiated with 0.5 and 1 kGy did not deviate in survival from the control groups. Animals from all exposed groups underwent their moulting and egg production cycle, but at decreasing frequency for doses above 1 kGy. No eggs laid by irradiated animals hatched, while eggs laid by controls did so. CONCLUSION Our study suggests that radiation tolerance in tardigrades is not due to biochemical protectants connected with the desiccated state. Rather, cryptobiotic tardigrades may rely on efficient mechanisms of DNA repair, the nature of which is currently unknown.
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Horikawa DD, Higashi S. Desiccation tolerance of the tardigrade Milnesium tardigradum collected in Sapporo, Japan, and Bogor, Indonesia. Zoolog Sci 2004; 21:813-6. [PMID: 15333992 DOI: 10.2108/zsj.21.813] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A tardigrade Milnesium tardigradum showed anhydrobiotic capacity, in which the desiccation tolerance, given by the mean survival rate under desiccation at different relative humidity levels, was significantly higher in the Sapporo (Japan) population than that in the Bogor (Indonesia) population. Accordingly, the surviving tardigrades took a significantly longer time for revival in Bogor than those in Sapporo. The higher tolerance of the Sapporo population is thought to be related to the low relative humidity and low temperature such that the animals experience 41% RH in May and often -10 degrees C or lower in winter.
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Affiliation(s)
- Daiki D Horikawa
- Graduate School of Environmental Earth Science, Hokkaido University, Sapporo 060-0810, Japan.
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27
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Ivarsson H, Jönsson KI. Aggregation effects on anhydrobiotic survival in the tardigrade Richtersius coronifer. ACTA ACUST UNITED AC 2004; 301:195-9. [PMID: 14743519 DOI: 10.1002/jez.a.20018] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
For anhydrobiotic metazoans the rate of desiccation is an important factor influencing the probability of survival in a dry anhydrobiotic state. Formation of animal aggregations, in which the exposed body surface area of individual animals is reduced, represents one way to reduce the rate of evaporation. Such aggregations have earlier been documented in e.g., nematodes. We experimentally evaluate the effect of aggregation size (number of animals in a group of desiccating animals) on anhydrobiotic survival in the eutardigrade Richtersius coronifer. The experiment shows that aggregation provides a clear improvement on anhydrobiotic survival. The most likely explanation for this is that aggregated animals were exposed to a lower rate of desiccation. Although the empirical evidence of aggregation in tardigrades is scarce, our study suggests that aggregation could potentially be an important survival factor for tardigrades living in environments characterized by periods of rapid desiccation.
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Affiliation(s)
- Helen Ivarsson
- Department of Theoretical Ecology, Lund University, 223 62 Lund, Sweden.
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