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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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Jezierska M, Miernik A, Sojka J, Student S, Śliwińska MA, Gross V, Poprawa I. Oogenesis in the tardigrade Hypsibius exemplaris Gąsiorek, Stec, Morek & Michalczyk, 2018 (Eutardigrada, Hypsibiidae). Micron 2021; 150:103126. [PMID: 34399159 DOI: 10.1016/j.micron.2021.103126] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 07/27/2021] [Accepted: 07/27/2021] [Indexed: 10/20/2022]
Abstract
Tardigrades are small, globally widespred invertebrates that need at least a thin layer of water to be active. There are gonochoric, hermaphroditic, and parthenogenetic species among them. The main aim of this study was to analyze the structure of the ovary, the structure of female germ cell clusters, and the course of oogenesis in the parthenogenetic species Hypsibius exemplaris, which in 2007 was recognized as a model organism. The material was analyzed using light and confocal microscopy as well as transmission and scanning electron microscopy. Histochemical and immunohistochemical methods were used. Our study showed that in the meroistic-polytrophic ovary of the examined species, branched germ cell clusters are formed in which one cell differentiates into an oocyte while the remaining cells become trophocytes. Vitellogenesis is of the mixed type: the first part of the yolk is synthesized by the oocyte (autosynthesis); the second part is synthesized by trophocytes and transported to the oocyte by cytoplasmic bridges; and the third part is synthesized outside the ovary (in storage cells) and transported to the oocyte by endocytosis. At the end of oogenesis, the trophocytes die by apoptosis. Parthenogenetic female of H. exemplaris lays from one to a dozen smooth eggs into exuviae.
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Affiliation(s)
- Marta Jezierska
- University of Silesia in Katowice, Faculty of Natural Sciences, Institute of Biology, Biotechnology and Environmental Protection, Bankowa 9, 40-007 Katowice, Poland; Department of Pathomorphology and Molecular Diagnostics, Medical University of Silesia, 40-055 Katowice, Poland.
| | - Aleksandra Miernik
- University of Silesia in Katowice, Faculty of Natural Sciences, Institute of Biology, Biotechnology and Environmental Protection, Bankowa 9, 40-007 Katowice, Poland
| | - Julia Sojka
- University of Silesia in Katowice, Faculty of Natural Sciences, Institute of Biology, Biotechnology and Environmental Protection, Bankowa 9, 40-007 Katowice, Poland
| | - Sebastian Student
- Silesian University of Technology, Institute of Automatic Control, Akademicka 16, 44-100 Gliwice, Poland; Silesian University of Technology, Biotechnology Centre, Krzywoustego 8, 44-100 Gliwice, Poland
| | - Małgorzata A Śliwińska
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Laboratory of Imaging Tissue Structure and Function, Ludwika Pasteura 3, 02-093, Warsaw, Poland
| | - Vladimir Gross
- University of Kassel, Institute of Biology, Department of Zoology, Heinrich-Plett-Straße 40, 34132 Kassel, Germany
| | - Izabela Poprawa
- University of Silesia in Katowice, Faculty of Natural Sciences, Institute of Biology, Biotechnology and Environmental Protection, Bankowa 9, 40-007 Katowice, Poland.
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Structure of the germarium and female germ-cell clusters in Thulinius ruffoi (Bertolani, 1982) (Tardigrada: Eutardigrada: Parachela). Zool J Linn Soc 2019. [DOI: 10.1093/zoolinnean/zlz108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
AbstractThulinius ruffoi is a freshwater species that has the ability to reproduce via parthenogenesis. A meroistic polytrophic ovary is present in this species. Analyses of the germarium structure, and formation and organization of female germ-cell clusters were performed using light, confocal laser scanning, transmission electron and serial block-face scanning electron microscopy. The germarium is the small, anterior part of an ovary that contains putative germ-line stem cells. In the studied species, the female germ-cell clusters are large and branched. Only one cell in each cluster develops into an oocyte, while all the other cells become trophocytes. In this paper, we present the first report on the presence of F-actin as a component of the intercellular bridges that connect the cells in the germ-cell cluster of T. ruffoi. Moreover, our results show that the female germ-cell clusters are formed as the result of both synchronous and asynchronous divisions and that their organization can vary not only between individuals of the investigated species, but also that clusters developing simultaneously within the same ovary can have a different spatial organization.
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Rost-Roszkowska M, Janelt K, Poprawa I. Ultrastructure of the midgut epithelium in three species of Macrobiotidae (Tardigrada: Eutardigrada: Parachela). Zool J Linn Soc 2019. [DOI: 10.1093/zoolinnean/zlz052] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
Three species of Macrobiotidae, Macrobiotus polonicus, Macrobiotus diversus and Macrobiotus pallarii, were selected for analysis of the fine structure of the midgut epithelium. They are gonochoric and carnivorous species that live in wet terrestrial and freshwater environments. The ultrastructure of the midgut epithelium of the investigated Macrobiotidae species was analysed in both males and females. Their digestive system is composed of fore- and hindguts that are covered by a cuticle, and the middle region, termed the midgut. It is lined with a simple epithelium that is formed by digestive cells that have a distinct brush border. Crescent-shaped cells that form an anterior ring in the border between the fore- and midgut were detected. The ultrastructure of the intestinal epithelium of the examined species differs slightly depending on sex. The digestive cells of the posterior segment of the intestine contain numerous lipid droplets, which are the reserve material. We concluded that the digestive cells of the Macrobiotidae midgut are responsible for its intracellular digestion owing to endocytosis. They also participate in the extracellular digestion owing to merocrine secretion (exocytosis). However, the midgut is not the main organ that accumulates reserve material. Additionally, the midgut epithelium does not participate in oogenesis.
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Affiliation(s)
- M Rost-Roszkowska
- University of Silesia in Katowice, Department of Animal Histology and Embryology, Katowice, Poland
| | - K Janelt
- University of Silesia in Katowice, Department of Animal Histology and Embryology, Katowice, Poland
| | - I Poprawa
- University of Silesia in Katowice, Department of Animal Histology and Embryology, Katowice, Poland
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Janelt K, Jezierska M, Poprawa I. The female reproductive system and oogenesis in Thulinius ruffoi (Tardigrada, Eutardigrada, Isohypsibiidae). ARTHROPOD STRUCTURE & DEVELOPMENT 2019; 50:53-63. [PMID: 31004762 DOI: 10.1016/j.asd.2019.04.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 04/15/2019] [Accepted: 04/16/2019] [Indexed: 06/09/2023]
Abstract
In this study, we describe the female reproductive system organization and oogenesis in the eutardigrade Thulinius ruffoi. Light, confocal and electron microscopy was used in this study. During oogenesis, three phases can be distinguished: previtellogenesis, vitellogenesis, and choriogenesis. Germ-line cells form cell clusters in which the cells are connected by intercellular (cytoplasmic) bridges. These structures are crucial for delivering the yolk materials, macromolecules, ribosomes, and organelles to the developing oocyte. Vitellogenesis is of a mixed type. Autosynthesis and heterosynthesis of the yolk material occur. Yolk precursors that have been synthesized outside the ovary are delivered to the oocyte via endocytosis. We also present data on cortical granules, and moreover, we describe the cortical reaction in tardigrades, possibly for the first time.
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Affiliation(s)
- Kamil Janelt
- University of Silesia in Katowice, Department of Animal Histology and Embryology, Bankowa 9, 40-007 Katowice, Poland.
| | - Marta Jezierska
- University of Silesia in Katowice, Department of Animal Histology and Embryology, Bankowa 9, 40-007 Katowice, Poland.
| | - Izabela Poprawa
- University of Silesia in Katowice, Department of Animal Histology and Embryology, Bankowa 9, 40-007 Katowice, Poland.
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