title: Autophagic activity in the midgut gland of the overwintering harvestmen Gyas annulatus (Phalangiidae, Opiliones).
abstract: Juvenile harvestmen Gyas annulatus overwinter in dormancy in hypogean habitats for 4-5 months. The ultrastructure of the autophagic structures in their midgut epithelium cells was studied by light microscopy, transmission electron microscopy (TEM) and immunofluorescence microscopy (IFM) during this non-feeding period. Before overwintering (November), autophagic structures were scarce. In the middle (January) and at the end of overwintering (March), phagophores, autophagosomes and autolysosomes were present in the cytoplasm of both the secretory and the digestive midgut epithelium cells, gradually increasing their abundance during overwintering. In addition, vacuolization of the cytoplasm intensified. Both processes are induced by starvation. Autophagic structures and cytoplasm vacuolization enable the reuse of the cell's own components required for the maintenance of vital processes during dormancy. While TEM is a much more convenient method for recognition of the autophagic structure types and their ultrastructure, IFM enables exact counting of these structures.
authors.affiliation: Medical Faculty, University of Maribor, Taborska ulica 8, SI-2000 Maribor, Slovenia; Department of Biology, Faculty of Natural Sciences and Mathematics, University of Maribor, Koroška cesta 160, SI-2000 Maribor, Slovenia; Faculty of Chemistry and Chemical Engineering, University of Maribor, Smetanova ulica 17, 2000 Maribor, Slovenia. Electronic address: sasa.lipovsek@uni-mb.si.
authors.forename: Saška
authors.initials: S
authors.lastname: Lipovšek
authors.affiliation: Department of Biology, Faculty of Natural Sciences and Mathematics, University of Maribor, Koroška cesta 160, SI-2000 Maribor, Slovenia.
authors.forename: Franc
authors.initials: F
authors.lastname: Janžekovič
authors.affiliation: Department of Biology, Faculty of Natural Sciences and Mathematics, University of Maribor, Koroška cesta 160, SI-2000 Maribor, Slovenia.
authors.forename: Tone
authors.initials: T
authors.lastname: Novak
mesh_terms: D000818:Animals; D001097:Arachnida / Q000502:physiology* / Q000648:ultrastructure; D001343:Autophagy; D059552:Caves; D004064:Digestive System / Q000648:ultrastructure; D005088:Exocrine Glands / Q000502:physiology / Q000648:ultrastructure; D005508:Food Deprivation; D008247:Lysosomes / Q000378:metabolism; D046529:Microscopy, Electron, Transmission; D008856:Microscopy, Fluorescence; D012621:Seasons
keywords: Arachnids; Autophagosomes; Degradation processes; Dormancy; Midgut gland