| 1. |
- Czernekova, Michaela, et al.
(författare)
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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
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Ingår i: PLOS ONE. - 1932-6203. ; 13:8
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Tidskriftsartikel (refereegranskat)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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| 2. |
- Czernekova, Michaela, et al.
(författare)
-
A comparative ultrastructure study of storage cells in the eutardigrade Richtersius coronifer in the hydrated state and after desiccation and heating stress
- 2018
-
Ingår i: PLoS ONE. - : Public Library of Science. - 1932-6203. ; 13:8
-
Tidskriftsartikel (refereegranskat)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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| 3. |
- Czernekova, Michaela, et al.
(författare)
-
Ultrastructure and 3D reconstruction of the tun in Richtersius coronifer (Richters, 1903)
- 2016
-
Konferensbidrag (refereegranskat)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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| 4. |
- Czernekova, Michaela, et al.
(författare)
-
Ultrastructure and 3D reconstruction of the tun in Richtersius coronifer (Richters, 1903)
- 2016
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)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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| 5. |
- Golas, Marta, et al.
(författare)
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Organisation of the capsule of Macrobiotus pallari and Richtersius coronifer (Tardigrada, Eutardigrada, Parachela)
- 2016
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Ingår i: ACTA BIOLOGICA CRACOVIENSIA. ; , s. 74-
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Konferensbidrag (refereegranskat)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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| 6. |
- Golas, Marta, et al.
(författare)
-
Organisation of the capsule of Macrobiotus pallari and Richtersius coronifer (Tardigrada, Eutardigrada, Parachela)
- 2016
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)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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