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.

Department of Animal Histology and Embryology Silesian University Katowice Poland

Faculty of Medicine Charles University Prague Czech Republic

Institute of Automatic Control Silesian University of Technology Gliwice Poland

Institute of Physiology Academy of Sciences of the Czech Republic Prague Czech Republic

School of Education and Environment Kristianstad University Kristianstad Sweden

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Tissue Cell. 1998 Jun;30(3):312-23 PubMed

J Morphol. 2003 Aug;257(2):246-53 PubMed

Tissue Cell. 2005 Oct;37(5):385-92 PubMed

Biol Bull. 2006 Dec;211(3):275-85 PubMed

Atti Accad Fisiocrit Siena Med Fis. 1968;17(2):1439-52 PubMed

Proc R Soc Lond B Biol Sci. 1959 Mar 17;150(939):149-91 PubMed

Curr Biol. 2008 Sep 9;18(17):R729-R731 PubMed

Parazitologiia. 2004 Jan-Feb;38(1):3-11 PubMed

Folia Biol (Krakow). 2005;53(3-4):173-7 PubMed

In Vitro Cell Dev Biol Anim. 2001 Jun;37(6):348-52 PubMed

Protoplasma. 2015 Jul;252(4):1019-29 PubMed

Biochim Biophys Acta. 2008 Dec;1783(12):2398-414 PubMed

Protoplasma. 2015 May;252(3):857-65 PubMed

Microbiol Rev. 1994 Dec;58(4):755-805 PubMed

J Cell Biol. 1963 Apr;17:208-12 PubMed

Prog Histochem Cytochem. 1985;16(2):1-84 PubMed

PLoS One. 2013 Dec 31;8(12):e85091 PubMed

Integr Comp Biol. 2005 Nov;45(5):810-20 PubMed

Arch Insect Biochem Physiol. 2001 Jun;47(2):47-61 PubMed

Micron. 2015 Mar;70:26-33 PubMed

Integr Comp Biol. 2005 Nov;45(5):710-4 PubMed

J Struct Biol. 2010 Jul;171(1):11-7 PubMed

J Ultrastruct Res. 1971 Feb;34(3):214-43 PubMed

Cell Tissue Res. 1976 Feb 25;166(3):339-51 PubMed

Folia Biol (Krakow). 2010;58(3-4):217-27 PubMed

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