| 1. |
- Jönsson, K. Ingemar, 1959-, et al.
(author)
-
Environmental adaptations : radiation tolerance
- 2019
-
In: Water bears. - : Springer. - 9783319957012 - 9783319957029 ; , s. 311-330
-
Book chapter (other academic/artistic)abstract
- Several studies in different species have documented that tardigrades are among the most radiation-tolerant animals on Earth, surviving doses of ionizing radiation on the order of kGy. Both low-LET and high-LET radiation have been used with no apparent differences in the tolerance of the animals. Tolerance to ionizing radiation in tardigrades also seems to be independent of whether the animal has entered a dry anhydrobiotic state or is hydrated with normal activity. However, when exposed to UV radiation, desiccated tardigrades show a higher tolerance than hydrated animals. Recent studies in several species have shown that tardigrade embryos have considerably lower tolerance to ionizing radiation compared to adults, and embryos in the early stage of development are clearly more sensitive to radiation than those in the late developmental stage. The molecular mechanisms behind radiation tolerance in tardigrades are still largely unclear, but available evidence suggests that mechanisms related to both the avoidance of DNA damage and the repair of damage are involved.
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| 2. |
- Jönsson, K. Ingemar, 1959-, et al.
(author)
-
The fate of the TARDIS offspring : no intergenerational effects of space exposure
- 2016
-
In: Zoological Journal of the Linnean Society. - 0024-4082 .- 1096-3642. ; 178:4, s. 924-930
-
Journal article (peer-reviewed)abstract
- In September 2007 tardigrades became the first animal in history to survive the combined effect of exposure to space vacuum, cosmic radiation and ultraviolet radiation in low Earth orbit. The main results from this experiment were reported in 2008, but some of the results have remained unpublished. Here we report that descendant generations of space-exposed tardigrades of the species Milnesium tardigradum did not show reduced performance. This indicates that individual tardigrades that survived the exposure to environmental extremes in space, and were able to reproduce, did not transfer any damage to later generations. Repair of environmentally induced damage may therefore follow a ‘make or break’ rule, such that a damaged animal either fails to repair all damage and dies, or repairs damage successfully and leaves no mutations to descendants. We also report that two additional tardigrade species, Echiniscus testudo and Ramazzottius oberhaeuseri, showed high survival after exposure to space vacuum and cosmic radiation within the TARDIS experiment.
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| 3. |
- Söderquist, Pär
(author)
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Large-scale releases of native species : the mallard as a predictive model system
- 2015
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Doctoral thesis (other academic/artistic)abstract
- Human alteration of natural systems, and its consequences are of great concern and the impact on global ecosystems is one of the biggest threats that biodiversity stands before. Translocations of invasive species, as well as intraspecific contingents with non-native genotypes, whether they are deliberate or unintentional, are one such alteration and its consequences are continuously being assessed. The mallard (Anas platyrhynchos) is the most numerous and widespread duck in the world and a flagship in wetland conservation. It is also an important game species which is heavily restocked for hunting purposes, especially in Europe where over three million ducklings are released every year. Because of its hunted status, its abundance, and the number of released individuals, it can serve as a model species to study effects of releases, both for conservation and restocking for hunting, on wild populations. In this thesis the status of the mallard was assessed in the Nordic countries and the effects of releases on the wild populations were studied by mining historical ringing data, comparing morphology of present-day wild, farmed, and historical mallards, and analyzing phylogeography of wild and farmed mallards in Europe. The status of the mallard population in the Nordic countries are generally good, however, a joint effort of European countries is needed to monitor and manage the population. A significant difference between wild and farmed mallards concerning longevity, migration, bill morphology and genetic structure was also found, together with signs of cryptic introgression of farmed genotypes in the wild population with potential fitness reduction as a result. The effect is however limited by that only a fraction of released farmed mallards reach the breeding season due to low survival. A natural captive environment is crucial to keep individuals wild-like with high survival rates after release. However, with an introgression of potentially maladapted farmed genotypes leading to a reduction in fitness, a low survival of released mallards would favor the wild population. A legislative change regarding obligation to report numbers, provenance, and release sites of farmed mallard should be considered, together with practical solutions of ringing and genetic monitoring of released mallards.
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| 4. |
- Arzel, Céline, et al.
(author)
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Time use and foraging behaviour in pre-breeding dabbling ducks Anas spp. in sub-arctic Norway
- 2015
-
In: Journal of Ornithology. - 2193-7192 .- 2193-7206. ; 156:2, s. 499-513
-
Journal article (peer-reviewed)abstract
- We studied time budgets and foraging methods in pre-breeding Mallard Anas platyrhynchos, (Eurasian) Teal Anas crecca, Wigeon Anas penelope, Pintail Anas acuta, Shoveler Anas clypeata and Gadwall Anas strepera in subarctic Norway in May. Among all six species studied, foraging accounted for the most common use of time, ranging from 19 % in male Pintail to 40–60 % in female Mallard, Teal, Pintail and Gadwall. Comfort behaviours amounted to 20–34 % of the time budget, and interaction and disturbance were marginal. Vigilance time ranged from 8 % in female Mallard to 20 % in male Pintail. Movement amounted to some 20 % of the time in most species and sexes. In Wigeon, sexes did not differ in time use, whereas in Mallard, Pintail and, in particular, Teal, females foraged more and engaged less in vigilance and interactions than did males. In addition, Teal and Mallard males engaged in the riskier foraging methods less than females, but more in those permitting vigilance. Although overlap in feeding methods was large among these species, Mallard and Teal were generalists, feeding at all depths, Wigeon foraged mainly in shallow water and Pintail foraged essentially in deep water. Our results support the income/capital breeder hypothesis with respect to males only; compared to lighter species, heavier species allocated less time to foraging but more to vigilance. We found no support for the hypothesis that long-distance migrants forage more to compensate for energy loss due to migratory flight. Foraging time in females was related to breeding phenology; early nesters spent more time feeding than later nesters.
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| 5. |
- Czernekova, Michaela, et al.
(author)
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A comparative ultrastructure study of storage cells in the eutardigrade Richtersius coronifer in the hydrated state and after desiccation and heating stress
- 2018
-
In: PLOS ONE. - 1932-6203. ; 13:8
-
Journal article (peer-reviewed)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 longterm 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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| 6. |
- Czernekova, Michaela, et al.
(author)
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Evaluation of extraction methods for quantitative analysis of tardigrade populations in soil and leaf litter
- 2018
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In: Pedobiologia. - : Elsevier. - 0031-4056 .- 1873-1511. ; 70, s. 1-5
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Journal article (peer-reviewed)abstract
- Accurate quantitative analysis of soil tardigrades depends on a relevant extraction method. Over the years, a number of different methods have been used, but the efficiency of these methods has rarely been evaluated for soil and leaf litter tardigrades. Four methods of extraction were compared in this study: the light-cooling (L-C) extractor, the high-gradient (H-G), Baermann extractor, the non-gradient (N-G) Baermann extractor and sieves.The results indicate that light and temperature are significant factors influencing tardigrade extraction. The L-C and H-G extractors were more effective than sieves for all substrate categories. These extraction methods (L-C and H-G) therefore seem to be appropriate for quantitative studies of soil and leaf litter tardigrades.
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| 7. |
- Czernekova, Michaela, et al.
(author)
-
Experimentally induced repeated anhydrobiosis in the Eutardigrade Richtersius coronifer
- 2016
-
In: PLOS ONE. - 1932-6203. ; 11:11
-
Journal article (peer-reviewed)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 numberof 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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| 8. |
- Czernekova, Michaela, et al.
(author)
-
Mitosis in storage cells of the eutardigrade Richtersius coronifer
- 2016
-
In: Zoological Journal of the Linnean Society. - 0024-4082 .- 1096-3642. ; 178:4, s. 888-896
-
Journal article (peer-reviewed)abstract
- Although tardigrades are sometimes reported as eutelic animals, mitosis has been reported in several somatic tissues of adult eutardigrades. The occurrence of cell division in storage cells is particularly interesting in light of the important role that these cells play in the physiology of tardigrades. We present data on the occurrence of mitosis in storage cells of the eutardigrade Richtersius coronifer (Richters, 1903), and analyse mitotic cells in relation to different body characteristics, including egg development stage, moulting, gut content, body length, number and size of oocytes, and shape and size of the storage cells. Mitosis was present in ~20% of all animals, and was more frequent in juveniles than in adults. The proportion of cells with mitosis (‘mitotic index’) was low: 0.76% in juveniles and 1.47% in adults. In juveniles, none of the measured phenotypic characters had significant predictive power for mitosis, whereas in adult animals in moult or in late egg developmental or post-laying stage were more likely to have mitotic storage cells. The association with the later part of the moulting process was particularly strong. The low mitotic index and the strong association with moulting suggests that mitosis in storage cells may be connected with somatic growth rather than cell renewal, and that the purpose of cell division may relate to a need of more cells to support the enlarged body after moulting. However, the specific life cycle of tardigrades, where energy intake and depletion, egg development, and moulting is highly intertwined and synchronized, make conclusions about the functional role of mitosis in storage cells difficult, however, and more studies are needed to reveal the mechanisms inducing mitosis in these interesting cells.
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| 9. |
- Czernekova, Michaela, et al.
(author)
-
Mitosis in storage cells of the eutardigrade Richtersius coronifer
- 2015
-
Conference paper (peer-reviewed)abstract
- Tardigrades are often reported as eutelic animals, characterized by a constant cell number after maturity and growing by cell enlargement rather than by increased cell number. However, mitosis has been reported in some of the somatic tissues of adult eutardigrades, including the storage cells, and are therefore not strictly eutelic. Very few studies have investigated the presence of mitosis in tardigrades, and the occurrence of cell division in storage cells is particularly interesting in light of the important role that these cells may play in the physiology and immunology of tardigrades. We present data on the occurrence of mitosis in storage cells of the eutardigrade Richtersius coronifer and provide an analysis of storage cell mitosis in relation to different body characteristics. Specimens were examined for mitotic cells using in toto staining with aceto-lactic orcein, and the same animals were characterized with respect to egg development stage, number of oocytes, gut content, body size, and shape and size of the storage cells. Mitosis was present in ca. 30% of the animals. A large majority (3/4) of the animals with mitotic cells were found in specimens at moulting or directly after egg laying. Amount of gut content was associated with mitosis, with highest mitosis frequency (ca. 50%) in animals with an empty gut. These results for egg developmental stage (incl. moulting) and gut content are however not independent, since gut content generally decrease towards the end of the reproductive cycle. Other measured body characteristics did not influence the frequency of mitosis. In juveniles, mitotic cells were found in about half of the examined specimens. Our results suggest that proliferation of storage cells in R. coronifer is connected to the general life cycle dynamics, and provide a basis for more in depth analyses of the functional role and dynamics of storage cells in tardigrades.
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| 10. |
- Czernekova, Michaela, et al.
(author)
-
Primary Culture of Tardigrade Storage Cells from Richtersius coronifer Richters, 1903
- 2016
-
Conference paper (peer-reviewed)abstract
- Coelomocytes are macrophage-like cells in the body cavity or the coelomic spaces of many invertebrates and play major roles in their physiology and immunology. Their structure, function and diversity, however, is still poorly understood.Tardigrades are micrometazoans inhabiting a wide variety of environments and with an ability to survive extreme conditions. Coelomocytes (“storage cells”) represent an important part of tardigrade physiology, storing and distributing energy and possibly also having immunological functions. Few studies of tardigrade cell biology have been reported and neither primary nor continuous cell cultures have been established. Tardigrades are normally found and also cultured in an environment rich in microorganisms, some of which may even be of symbiotic value.In this study we have tried to establish a primary culture of storage cells in the eutardigrade Richtersius coronifer. Different cell media and concentrations of fetal bovine serum (FBS) were tested. Extracting cells from the tardigrades in an antiseptical environment is challenging since it has to be done under a microscope and contamination from the tardigrades surface is also a problem. To avoid this we tried culturing with high concentrations of antibiotics and antimycotics. We managed to keep the cells viable for up to 18 days in Grace insect medium with 10 % FBS at 20-22°C. The medium was changed every third day. 10x Antibiotic-Antimycotic and 5x of Penicillin-Streptomycin were used to minimize contamination. These concentrations reduce the bacterial abundance, but contamination with fungi was still an issue. Cell morphology evaluation was performed daily and no obvious toxic effects on the cells was observed. Cell viability and cell division were evaluated with Trypan blue staining and cell counting in a haemocytometer. The results indicate that the cells are viable and that some cell division occurs, however more studies need to be performed to confirm this. Still, this study provides the first evidence that primary cultures of storage cells from tardigrades are possible to establish, but the culturing method has to be refined to avoid contamination.
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| 11. |
- Czernekova, Michaela, et al.
(author)
-
The structure of the desiccated Richtersius coronifer (Richters, 1903)
- 2017
-
In: Protoplasma. - 0033-183X .- 1615-6102. ; 254:3, s. 1367-1377
-
Journal article (peer-reviewed)abstract
- Tun formation is an essential morphological adaptation for entering the anhydrobiotic state in tardigrades, but its internal structure has rarely been investigated. We present the structure and ultrastructure of organs and cells in desiccated Richtersius coronifer by transmission and scanning electron microscopy, confocal microscopy, and histochemical methods. A 3D reconstruction of the body organization of the tun stage is also presented. The tun formation during anhydrobiosis of tardigrades is a process of anterior-posterior body contraction, which relocates some organs such as the pharyngeal bulb. The cuticle is composed of epicuticle, intracuticle and procuticle; flocculent coat; and trilaminate layer. Moulting does not seem to restrict the tun formation, as evidenced from tardigrade tuns that were in the process of moulting. The storage cells of desiccated specimens filled up the free inner space and surrounded internal organs, such as the ovary and digestive system, which were contracted. All cells (epidermal cells, storage cells, ovary cells, cells of the digestive system) underwent shrinkage, and their cytoplasm was electron dense. Lipids and polysaccharides dominated among reserve material of storage cells, while the amount of protein was small. The basic morphology of specific cell types and organelles did not differ between active and anhydrobiotic R. coronifer.
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| 12. |
- Czernekova, Michaela, et al.
(author)
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Ultrastructure and 3D reconstruction of the tun in Richtersius coronifer (Richters, 1903)
- 2016
-
Conference paper (peer-reviewed)abstract
- Anhydrobiosis is one of the types of cryptobiosis that is caused by lack of water (desiccation). Formation of a tun seems to be the most important morphological adaptation for entering anhydrobiotic state. During this process the tardigrade body undergo anterior-posterior contraction that causes relocation of some organs such as the pharyngeal bulb. The tun wall of Richtersius coronifer (Eutardigrada, Macrobiotidae) was composed of multilayered cuticle and epidermis. The epidermis consisted of the single squamous epithelium whose cells were shrunken whereas the cuticle was composed of epi-, intra- and procuticle, flocculent coat and trilaminate layer. The storage cells of desiccated specimens filled up free inner space and surrounded the internal organs (ovary, digestive system) that were contracted. All cells of the body underwent shrinking and their metabolism was arrested. The cytoplasm of all cells was electron dense but the basic morphology of cells and organelles did not differ between active and anhydrobiotic animals. The structure and the ultrastructure of the desiccated Richtersius coronifer have been described with light and confocal microscopy as well as transmission and scanning electron microscopy. 3D reconstruction of tun based on the series of semi-thin sections was prepared with IMARIS 8.2 software (Bitplane).
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| 13. |
- Elmberg, Johan, 1960-
(author)
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Goose poop in the park
- 2018
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In: Bottom Line Health. - 1092-0129. ; 32:6
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Journal article (peer-reviewed)
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| 14. |
- Elmberg, Johan, 1960-, et al.
(author)
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Passage patterns of seabirds in October at Cabo Carvoeiro Portugal, with special reference to the Balearic Shearwater Puffinus mauretanicus
- 2016
-
In: Marine Ornithology. - 1018-3337 .- 2074-1235. ; 44:2, s. 151-156
-
Journal article (peer-reviewed)abstract
- Land-based counts of migrating seabirds remain essential to increase knowledge about their numbers and movements. To assess the value of Cabo Carvoeiro (Peniche, Portugal) as a monitoring site in the East Atlantic, we studied seabird species composition, passage patterns and flock size during mid-October 2014. During standardized counts, we observed nearly 8 000 seabirds of 17 species. The ratio of individuals passing in a southerly to southwesterly direction was >96% in all species, showing that genuine migrants were counted. The passage rate (birds/hour) was higher for Northern Gannets Morus bassanus than for any other species, by a factor of approximately 50 (morning mean 906/h, afternoon mean 1 153/h). The globally endangered Balearic Shearwaters Puffinus mauretanicus, Great Skuas Stercorarius skua and Pomarine Skuas S. pomarinus had passage rates of 10–25/h. Flock size distribution in the 11 most numerous species showed that most migrated singly or in groups of two. Flock size was larger in Balearic Shearwaters than in both Cory’s Calonectris borealis and Manx Shearwaters P. puffinus. Among skuas, flock size was larger in Pomarine than in Great Skuas. The passage rate of Manx Shearwaters was positively correlated with that of Northern Gannets, Great Skuas and Sandwich Terns Sterna sandvicensis. Northern Gannets showed a positive co-variation with Pomarine Skuas. Balearic and Sooty Shearwaters Ardenna griseus were the only species that did not show any significant co-variation with another species. Morning and afternoon passage rates did not differ significantly in any of the six most numerous species (Northern Gannets, Cory’s and Balearic Shearwaters, Great and Pomarine Skuas, and Sandwich Terns), or in Sooty Shearwaters (less numerous). Thus, the passage rates at Cabo Carvoeiro in October of Balearic Shearwaters and five other species were as high or higher than those reported from any other seawatch in Portugal, indicating the international value of seabird monitoring at Cabo Carvoeiro during the autumn migration.
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| 15. |
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| 16. |
- Golas, Marta, et al.
(author)
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Organisation of the capsule of Macrobiotus pallari and Richtersius coronifer (Tardigrada, Eutardigrada, Parachela)
- 2016
-
In: ACTA BIOLOGICA CRACOVIENSIA. ; , s. 74-
-
Conference paper (peer-reviewed)abstract
- Organisation of the egg capsule of two species of tardigrades belonging to the family Macrobiotidae, Macrobiotus pallari and Richtersius coronifer, was analysed using light, transmission and scanning electron microscopy. In both cases, similar to other Macrobiotidae (Węglarska, 1982; Poprawa etal., 2015) egg capsule was composed of thin vitelline envelope and three-layered chorion. The chorion consisted of: (1) the inner, medium electron-dense layer – endochorion, (2) the middle, labyrinthine layer and (3) the outer, medium electron-dense layer – exochorion. The yellow chorion of Richtersius coronifer was covered with elongated processes having irregular granulation ontheir surface. These processes were empty inside. They were formed by evagination of exochorion. The basic chorion connecting processes was smooth and covered with irregular granulation. The chorion of Macrobiotus pallari was white. Its surface was covered with conical processes and areolation between them. The tips of processes were elongated and formed bushy structure. The surface of conical processes has a form of sculpture composed of thin rings. The processes that were empty inside, were formed by evagination of exochorion and labyrinthine layer.
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| 17. |
- Guidetti, Roberto, et al.
(author)
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Morphological and molecular analyses on Richtersius (Eutardigrada) diversity reveal its new systematic position and lead to the establishment of a new genus and a new family within Macrobiotoidea
- 2016
-
In: Zoological Journal of the Linnean Society. - 0024-4082 .- 1096-3642. ; 178:4, s. 834-845
-
Journal article (peer-reviewed)abstract
- Important contributions have been made to the systematics of Eutardigrada in recent years, but these have also revealed that several taxa are polyphyletic and that cryptic species are present. To shed light on the taxonomy and systematic position of the genus Richtersius (Eutardigrada, Macrobiotoidea), six populations attributed to Richtersius coronifer were collected and analysed from morphological (light and scanning electron microscopy) and molecular (mitochondrial cytochrome oxidase subunit 1, 18S, 28S) points of view. In particular, a new morphometric index (claw common tract: length of the common tract of the claw/total claw length × 100) and a new morphological character (stalk system) were introduced. Our integrative study was able to unveil the ‘cryptic’ species diversity within Richtersius, showing that the genus contains more than one evolutionary lineage. A morphological peculiarity in the animals of all lineages is the dimorphism in the morphology of the cuticle. Cuticular pores are present in the newborns and are lost with the first moult; this morphological change represents a novelty in the life cycle of eutardigrades. The phylogenetic analyses carried out on Richtersius populations and other Macrobiotoidea show that Richtersius is closely related to Macrobiotus islandicus, whereas Adorybiotus granulatus is more related to Richtersius and M. islandicus than to other members of the genus Macrobiotus (type genus of Macrobiotidae); therefore, the genus Macrobiotus and the family Macrobiotidae are not monophyletic. Based on these results, the new genus Diaforobiotus (for M. islandicus) and the new family Richtersiidae (composed of Richtersius, Diaforobiotus gen. nov., and Adorybiotus) are established.
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| 18. |
- Jönsson, K. Ingemar, 1959-
(author)
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Radiation tolerance in tardigrades : current knowledge and potential applications in medicine
- 2019
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In: Cancers. - 2072-6694. ; 11:9
-
Research review (peer-reviewed)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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| 19. |
- Jönsson, K. Ingemar, et al.
(author)
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The fate of the TARDIS offspring : no intergenerational effects of space exposure in Milnesium tardigradum
- 2015
-
Conference paper (peer-reviewed)abstract
- In September 2007 tardigrades became the first animal in the history to survive the combined effect of exposure to space vacuum, cosmic radiation, and ultra-violet radiation in low Earth orbit. The main results from this experiment were reported in 2008, but some of the results have remained unpublished. Here we report that no delayed effects of the exposure to space could be detected in the descendants (up to F3 generation) of space exposed Milnesium tardigradum. This indicates that individual tardigrades that survived the damage induced by environmental agents in space, and were able to reproduce, did not transfer any delayed damage to later generations. Repair of environmentally induced damage may therefore follow a “make or break” rule, such that a damaged animal either fails to repair all damage and dies, or repairs damage successfully and leaves no mutations to descendants. We also provide previously unreported data on two tardigrade species, Echiniscus testudo and Ramazzottius oberhaeuseri, that showed high survival after exposure to space vacuum and cosmic radiation within the TARDIS experiment.
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| 20. |
- Jönsson, K. Ingemar, 1959-, et al.
(author)
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Tolerance to gamma radiation in the marine heterotardigrade, Echiniscoides sigismundi
- 2016
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In: PLOS ONE. - 1932-6203. ; 11:12
-
Journal article (peer-reviewed)abstract
- Tardigrades belong to the most radiation tolerant animals on Earth, as documented by a number of studies using both low-LET and high-LET ionizing radiation. Previous studies have focused on semi-terrestrial species, which are also very tolerant to desiccation. The predominant view on the reason for the high radiation tolerance among these semi-terrestrial species is that it relies on molecular mechanisms that evolved as adaptations for surviving dehydration. In this study we report the first study on radiation tolerance in a marine tardigrade, Echiniscoides sigismundi. Adult specimens in the hydrated active state were exposed to doses of gamma radiation from 100 to 5000 Gy. The results showed little effect of radiation at 100 and 500 Gy but a clear decline in activity at 1000 Gy and higher. The highest dose survived was 4000 Gy, at which ca. 8% of the tardigrades were active 7 days after irradiation. LD50 in the first 7 days after irradiation was in the range of 1100±1600 Gy. Compared to previous studies on radiation tolerance in semi-terrestrial and limnic tardigrades, Echiniscoides sigismundi seems to have a lower tolerance. However, the species still fits into the category of tardigrades that have high tolerance to both desiccation and radiation, supporting the hypothesis that radiation tolerance is a by-product of adaptive mechanisms to survive desiccation. More studies on radiation tolerance in tardigrade species adapted to permanently wet conditions, both marine and freshwater, are needed to obtain a more comprehensive picture of the patterns of radiation tolerance.
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| 21. |
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| 22. |
- Pöysä, Hannu, et al.
(author)
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Habitat associations and habitat change : seeking explanation for population decline in breeding Eurasian wigeon Anas penelope
- 2017
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In: Hydrobiologia. - : Springer Verlag (Germany). - 0018-8158 .- 1573-5117. ; 785:1, s. 207-217
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Journal article (peer-reviewed)abstract
- We explored whether the recent large-scale population decline of Eurasian wigeon (Anas penelope) in Europe may be linked to long-term vegetation changes in their boreal breeding wetlands. First, we assessed the importance of Equisetum, Phragmites, and Carex stands in lake selection by pairs and in foraging habitat selection by broods. Second, in 2013–2014 we revisited 58 lakes in Sweden and Finland studied in 1990–1991, to examine if there had been any long-term change in the abundance of habitat types preferred by wigeon. Finally, using continuous long-term data on breeding numbers of wigeon in 18 of the lakes studied in 1990–1991, we examined if wigeon numbers had changed at lakes where the habitat also had changed. We found that lake occupation of nesting wigeon pairs and foraging habitat use of broods were associated with the extent of Equisetum stands. The presence and abundance of this preferred habitat declined dramatically from 1990–1991 to 2013–2014 in the lakes from which the presence–absence data of wigeon emanate. Breeding numbers of wigeon showed a long-term declining trend in lakes where Equisetum has decreased. Our results imply that the recent population decline of wigeon in Europe may be linked to decrease of Equisetum habitat.
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| 23. |
- Tuvendal, Magnus, et al.
(author)
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A handshake between markets and hierarchies : geese as an example of successful collaborative management of ecosystem services
- 2015
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In: Sustainability. - 2071-1050. ; 7:12, s. 15937-15954
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Journal article (peer-reviewed)abstract
- An important task in research about natural resource management is to communicate the utility of different approaches from various settings. Using ecosystem services as a conceptual frame, we study a local solution to alleviate goose-human conflicts in an agricultural region in Sweden. Increasing goose numbers and crop damage led to the foundation of a goose management group (GMG), comprising landowners, farmers, hunters, ornithologists, conservation NGOs, and local and county level administration. The GMG was not given any formal or legal authority. We asked: is this management solution successful? Which problems can be solved and which remain? Can the GMG stand as a model for management of other species and in other landscapes? We interviewed present members of the GMG and analyzed minutes from its meetings. We found that the GMG has autonomy to self-organize and shows adaptive capacity over time in handling variability and complexity in its socio-ecological system. This makes the GMG a sustainable solution for local management of a resource in which goose population growth and legislation are decided at other (national or international) levels. We assessed what constitutes perceived success and found that GMG is geared toward “mediation of opposing preferences” by establishing a figurative handshake between stakeholders. By comparing how four general challenges in ecosystem service management align with formative attributes of the GMG, we discuss in which ways this management solution is applicable to other ecosystem services in other contexts.
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| 24. |
- Vecchi, Matteo, et al.
(author)
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Integrative systematic studies on tardigrades from Antarctica identify new genera and new species within Macrobiotoidea and Echiniscoidea
- 2016
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In: Invertebrate systematics. - 1445-5226 .- 1447-2600. ; 30:4, s. 303-322
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Journal article (peer-reviewed)abstract
- Tardigrades represent one of the most abundant groups of Antarctic metazoans in terms of abundance and diversity, thanks to their ability to withstand desiccation and freezing; however, their biodiversity is underestimated. Antarctic tardigrades from Dronning Maud Land and Victoria Land were analysed from a morphological point of view with light microscopy and scanning electron microscopy, and from a molecular point of view using two genes (18S, 28S) analysed in Bayesian inference and maximum-likelihood frameworks. In addition, indel-coding datasets were used for the first time to infer tardigrade phylogenies. We also compared Antarctic specimens with those from Italy and Greenland. A combined morphological and molecular analysis led to the identification of two new evolutionary lineages, for which we here erect the new genera Acanthechiniscus, gen. nov. (Echiniscidae, Echiniscoidea) and Mesobiotus, gen. nov. (Macrobiotidae, Macrobiotoidea). Moreover, two species new to science were discovered: Pseudechiniscus titianae,sp. nov. (Echiniscidae : Echiniscoidea) and Mesobiotus hilariae, sp. nov. (Macrobiotidae : Macrobiotoidea). This study highlights the high tardigrade diversity in Antarctica and the importance of an integrated approach in faunal and taxonomic studies.
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