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Janelt K, Wieczorkiewicz F, Poprawa I. The organisation of the digestive, excretory and reproductive systems in cysts of the freshwater tardigrade Thulinius ruffoi (Parachela, Isohypsibioidea: Doryphoribiidae). Micron 2024; 183:103660. [PMID: 38820862 DOI: 10.1016/j.micron.2024.103660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2024] [Revised: 05/18/2024] [Accepted: 05/20/2024] [Indexed: 06/02/2024]
Abstract
Tardigrades are invertebrates known to science for over 250 years. Although the ability of some species of tardigrades to form cysts has been reported, little is known about the encystment and internal organisation of the cysts. During cyst formation, contraction of the body affects the internal organs' morphology. The organs are compressed and have a compact appearance. The organisation of the digestive system, associated structures, and the reproductive system are analysed in cysts on indefinite and well-defined encystment periods - up to eleven months. The digestive system of encysted animals was organised into three main parts - a foregut, a midgut, and a hindgut. The presence of digestive system-associated structures, such as buccal glands or muscles, was noted and described. The excretory organs, called Malpighian tubules, open into the zone between the midgut and the hindgut. Furthermore, the oviduct opens into the hindgut. The first analysis of the reproductive system of cysts at the ultrastructural level is presented here, revealing interesting and undescribed aspects related to the physiology. Besides the anatomical and histological examination, the morphology and changes that occur during cyst formation are described.
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Affiliation(s)
- Kamil Janelt
- Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia in Katowice, Bankowa 9, Katowice 40-007, Poland; Department of Medical Genetics, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Medyków 18, Katowice 40-752, Poland.
| | - Filip Wieczorkiewicz
- Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia in Katowice, Bankowa 9, Katowice 40-007, Poland
| | - Izabela Poprawa
- Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia in Katowice, Bankowa 9, Katowice 40-007, Poland.
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Møbjerg N, Jørgensen A, Kristensen RM, Neves RC. Morphology and Functional Anatomy. WATER BEARS: THE BIOLOGY OF TARDIGRADES 2018. [DOI: 10.1007/978-3-319-95702-9_2] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Persson DK, Halberg KA, Jørgensen A, Møbjerg N, Kristensen RM. Neuroanatomy ofHalobiotus crispae(Eutardigrada: Hypsibiidae): Tardigrade brain structure supports the clade panarthropoda. J Morphol 2012; 273:1227-45. [DOI: 10.1002/jmor.20054] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Revised: 04/26/2012] [Accepted: 05/27/2012] [Indexed: 12/18/2022]
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Halberg KA, Møbjerg N. First evidence of epithelial transport in tardigrades: a comparative investigation of organic anion transport. J Exp Biol 2012; 215:497-507. [DOI: 10.1242/jeb.065987] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
SUMMARY
We investigated transport of the organic anion Chlorophenol Red (CPR) in the tardigrade Halobiotus crispae using a new method for quantifying non-fluorescent dyes. We compared the results acquired from the tardigrade with CPR transport data obtained from Malpighian tubules of the desert locust Schistocerca gregaria. CPR accumulated in the midgut lumen of H. crispae, indicating that organic anion transport takes place here. Our results show that CPR transport is inhibited by the mitochondrial un-coupler DNP (1 mmol l–1; 81% reduction), the Na+/K+-ATPase inhibitor ouabain (10 mmol l–1; 21% reduction) and the vacuolar H+-ATPase inhibitor bafilomycin (5 μmol l–1; 21% reduction), and by the organic anions PAH (10 mmol l–1; 44% reduction) and probenecid (10 mmol l–1; 61% reduction, concentration-dependent inhibition). Transport by locust Malpighian tubules exhibits a similar pharmacological profile, albeit with markedly higher concentrations of CPR being reached in S. gregaria. Immunolocalization of the Na+/K+-ATPase α-subunit in S. gregaria revealed that this transporter is abundantly expressed and localized to the basal cell membranes. Immunolocalization data could not be obtained from H. crispae. Our results indicate that organic anion secretion by the tardigrade midgut is transporter mediated with likely candidates for the basolateral entry step being members of the Oat and/or Oatp transporter families. From our results, we cautiously suggest that apical H+ and possibly basal Na+/K+ pumps provide the driving force for the transport; the exact coupling between electrochemical gradients generated by the pumps and transport of ions, as well as the nature of the apical exit step, are unknown. This study is, to our knowledge, the first to show active epithelial transport in tardigrades.
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Affiliation(s)
- Kenneth Agerlin Halberg
- Department of Biology, The August Krogh Building, University of Copenhagen, Universitetsparken 13, DK-2100 Copenhagen Ø, Denmark
| | - Nadja Møbjerg
- Department of Biology, The August Krogh Building, University of Copenhagen, Universitetsparken 13, DK-2100 Copenhagen Ø, Denmark
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Halberg KA, Larsen KW, Jørgensen A, Ramløv H, Møbjerg N. Inorganic ion composition in Tardigrada: cryptobionts contain large fraction of unidentified organic solutes. J Exp Biol 2012; 216:1235-43. [DOI: 10.1242/jeb.075531] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Summary
Many species of tardigrades are known to tolerate extreme environmental stress, yet detailed knowledge of the mechanisms underlying the remarkable adaptations of tardigrades is still lacking, as are answers to many questions regarding their basic biology. Here, we present data on the inorganic ion composition and total osmotic concentration of five different species of tardigrades (Echiniscus testudo, Milnesium tardigradum, Richtersius coronifer, Macrobiotus cf. hufelandi and Halobiotus crispae) using high-performance liquid chromatography and nanoliter osmometry. Quantification of the ionic content indicates that Na+ and Cl- are the principle inorganic ions in tardigrade fluids, albeit other ions, i.e. K+, NH4+, Ca2+, Mg2+, F-, SO42- and PO43- were also detected. In limno-terrestrial tardigrades, the respective ions are concentrated by a large factor compared to that of the external medium (Na+, ×70-800; K+, ×20-90; Ca2+ and Mg2+, ×30-200; F-, ×160-1040, Cl-, ×20-50; PO43-, ×700-2800; SO42-, ×30-150). In contrast, in the marine species H. crispae Na+, Cl- and SO42- are almost in ionic equilibrium with (brackish) salt water, while K+, Ca2+, Mg2+ and F- are only slightly concentrated (×2-10). An anion deficit of ~120 mEq 1-1 in M. tardigradum and H. crispae indicates the presence of unidentified ionic components in these species. Body fluid osmolality ranges from 361±49 mOsm kg-1 in R. coronifer to 961±43 mOsm kg-1 in H. crispae. Concentrations of most inorganic ions are largely identical between active and dehydrated groups of R. coronifer, suggesting that this tardigrade does not lose large quantities of inorganic ions during dehydration. The large osmotic and ionic gradients maintained by both limno-terrestrial and marine species are indicative of a powerful ion-retentive mechanism in Tardigrada. Moreover, our data indicate that cryptobiotic tardigrades contain a large fraction of unidentified organic osmolytes, the identification of which is expected to provide increased insight into the phenomenon of cryptobiosis.
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Møbjerg N, Halberg KA, Jørgensen A, Persson D, Bjørn M, Ramløv H, Kristensen RM. Survival in extreme environments - on the current knowledge of adaptations in tardigrades. Acta Physiol (Oxf) 2011; 202:409-20. [PMID: 21251237 DOI: 10.1111/j.1748-1716.2011.02252.x] [Citation(s) in RCA: 125] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Tardigrades are microscopic animals found worldwide in aquatic as well as terrestrial ecosystems. They belong to the invertebrate superclade Ecdysozoa, as do the two major invertebrate model organisms: Caenorhabditis elegans and Drosophila melanogaster. We present a brief description of the tardigrades and highlight species that are currently used as models for physiological and molecular investigations. Tardigrades are uniquely adapted to a range of environmental extremes. Cryptobiosis, currently referred to as a reversible ametabolic state induced by e.g. desiccation, is common especially among limno-terrestrial species. It has been shown that the entry and exit of cryptobiosis may involve synthesis of bioprotectants in the form of selective carbohydrates and proteins as well as high levels of antioxidant enzymes and other free radical scavengers. However, at present a general scheme of mechanisms explaining this phenomenon is lacking. Importantly, recent research has shown that tardigrades even in their active states may be extremely tolerant to environmental stress, handling extreme levels of ionizing radiation, large fluctuation in external salinity and avoiding freezing by supercooling to below -20 °C, presumably relying on efficient DNA repair mechanisms and osmoregulation. This review summarizes the current knowledge on adaptations found among tardigrades, and presents new data on tardigrade cell numbers and osmoregulation.
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Affiliation(s)
- N Møbjerg
- Department of Biology, University of Copenhagen, Copenhagen, Denmark.
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Smykla J, Kaczmarek Ł, Huzarska K, Michalczyk Ł. The first record of a rare marine tardigrade, Halobiotus crispae Kristensen, 1982 (Eutardigrada: Hypsibiidae), from the Svalbard Archipelago. Polar Biol 2011. [DOI: 10.1007/s00300-011-0986-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Halberg KA, Persson D, Møbjerg N, Wanninger A, Kristensen RM. Myoanatomy of the marine tardigrade Halobiotus crispae (Eutardigrada: Hypsibiidae). J Morphol 2009; 270:996-1013. [PMID: 19274743 DOI: 10.1002/jmor.10734] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The muscular architecture of Halobiotus crispae (Eutardigrada: Hypsibiidae) was examined by means of fluorescent-coupled phalloidin in combination with confocal laser scanning microscopy and computer-aided three-dimensional reconstruction, in addition to light microscopy (Nomarski), scanning electron microscopy, and transmission electron microscopy (TEM). The somatic musculature of H. crispae is composed of structurally independent muscle fibers, which can be divided into a dorsal, ventral, dorsoventral, and a lateral musculature. Moreover, a distinct leg musculature is found. The number and arrangement of muscles differ in each leg. Noticeably, the fourth leg contains much fewer muscles when compared with the other legs. Buccopharyngeal musculature (myoepithelial muscles), intestinal musculature, and cloacal musculature comprise the animal's visceral musculature. TEM of stylet and leg musculature revealed ultrastructural similarities between these two muscle groups. Furthermore, microtubules are found in the epidermal cells of both leg and stylet muscle attachments. This would indicate that the stylet and stylet glands are homologues to the claw and claw glands, respectively. When comparing with previously published data on both heterotardigrade and eutardigrade species, it becomes obvious that eutardigrades possess very similar numbers and arrangement of muscles, yet differ in a number of significant details of their myoanatomy. This study establishes a morphological framework for the use of muscular architecture in elucidating tardigrade phylogeny.
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Affiliation(s)
- Kenneth Agerlin Halberg
- Department of Biology, The August Krogh Building, University of Copenhagen, DK-2100 Copenhagen Ø, Denmark.
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Halberg KA, Persson D, Ramløv H, Westh P, Kristensen RM, Møbjerg N. Cyclomorphosis in Tardigrada: adaptation to environmental constraints. J Exp Biol 2009; 212:2803-11. [DOI: 10.1242/jeb.029413] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
Tardigrades exhibit a remarkable resilience against environmental extremes. In the present study, we investigate mechanisms of survival and physiological adaptations associated with sub-zero temperatures and severe osmotic stress in two commonly found cyclomorphic stages of the marine eutardigrade Halobiotus crispae. Our results show that only animals in the so-called pseudosimplex 1 stage are freeze tolerant. In pseudosimplex 1, as well as active-stage animals kept at a salinity of 20 ppt, ice formation proceeds rapidly at a crystallization temperature of around –20°C,revealing extensive supercooling in both stages, while excluding the presence of physiologically relevant ice-nucleating agents. Experiments on osmotic stress tolerance show that the active stage tolerates the largest range of salinities. Changes in body volume and hemolymph osmolality of active-stage specimens (350–500 μm) were measured following salinity transfers from 20 ppt. Hemolymph osmolality at 20 ppt was approximately 950 mOsm kg–1. Exposure to hypo-osmotic stress in 2 and 10 ppt caused(1) rapid swelling followed by a regulatory volume decrease, with body volume reaching control levels after 48 h and (2) decrease in hemolymph osmolality followed by a stabilization at significantly lower osmolalities. Exposure to hyperosmotic stress in 40 ppt caused (1) rapid volume reduction, followed by a regulatory increase, but with a new steady-state after 24 h below control values and (2) significant increase in hemolymph osmolality. At any investigated external salinity, active-stage H. crispaehyper-regulate, indicating a high water turnover and excretion of dilute urine. This is likely a general feature of eutardigrades.
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Affiliation(s)
- Kenneth Agerlin Halberg
- Department of Biology, University of Copenhagen, August Krogh Building,Universitetsparken 13, DK-2100 Copenhagen Ø, Denmark
| | - Dennis Persson
- Department of Biology, University of Copenhagen, August Krogh Building,Universitetsparken 13, DK-2100 Copenhagen Ø, Denmark
- Natural History Museum of Denmark, Zoological Museum, Invertebrate Department,Universitetsparken 15, DK-2100 Copenhagen Ø, Denmark
| | - Hans Ramløv
- Department of Nature, Systems and Models, University of Roskilde,Universitetsvej 1, DK-4000 Roskilde, Denmark
| | - Peter Westh
- Department of Nature, Systems and Models, University of Roskilde,Universitetsvej 1, DK-4000 Roskilde, Denmark
| | - Reinhardt Møbjerg Kristensen
- Natural History Museum of Denmark, Zoological Museum, Invertebrate Department,Universitetsparken 15, DK-2100 Copenhagen Ø, Denmark
| | - Nadja Møbjerg
- Department of Biology, University of Copenhagen, August Krogh Building,Universitetsparken 13, DK-2100 Copenhagen Ø, Denmark
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Lipovsek Delakorda S, Letofsky-Papst I, Novak T, Hofer F, Pabst MA. Structure of the Malpighian tubule cells and annual changes in the structure and chemical composition of their spherites in the cave cricket Troglophilus neglectus Krauss, 1878 (Rhaphidophoridae, Saltatoria). ARTHROPOD STRUCTURE & DEVELOPMENT 2009; 38:315-327. [PMID: 19303052 DOI: 10.1016/j.asd.2009.02.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2009] [Revised: 02/18/2009] [Accepted: 02/25/2009] [Indexed: 05/27/2023]
Abstract
Periodical changes in the structure of spherites in the Malpighian tubule cells of the cave cricket Troglophilus neglectus were studied to elucidate their role during the cricket's life cycle in natural circumstances. Special interest was given to the dormant overwintering period when we hypothesized that the primary role of spherites is to supply minerals for basic vital processes. The investigation was carried out by light and transmission electron microscopy, energy dispersive X-ray spectroscopy, electron energy-loss spectroscopy and energy-filtering TEM. Spherites are present only in the middle Malpighian tubule segment, consisting of Type 1 cells, characterized, among other features, by a round, apically placed nucleus and numerous spherites, and a few Type 2 cells with an elongated nucleus in the centre and sparse spherites. At the beginning of dormancy in November juveniles, minerals are accumulated in spherites and then decline until March. In one-year-old May larvae, spherites are commonly rich in minerals, and from July onwards they are progressively exploited in the adults. Spherite destruction starts with apoptosis in senile October individuals. The findings suggest that the mineral supply of spherites in Malpighian tubules is crucial to supporting vital processes throughout the life cycle of T. neglectus.
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Affiliation(s)
- Saska Lipovsek Delakorda
- Department of Biology, Faculty of Natural Sciences and Mathematics, University of Maribor, Koroska 160, SI-2000 Maribor, Slovenia.
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Eibye-Jacobson J. A New Method for Making SEM Preparations of the Tardigrade Buccopharyngeal Apparatus. ZOOL ANZ 2001. [DOI: 10.1078/0044-5231-00038] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Edgecombe GD, Wilson GD, Colgan DJ, Gray MR, Cassis G. Arthropod Cladistics: Combined Analysis of Histone H3 and U2 snRNA Sequences and Morphology. Cladistics 2000; 16:155-203. [DOI: 10.1111/j.1096-0031.2000.tb00352.x] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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