Differentiation of somatic cells in the ovariuteri of the apoikogenic scorpion Euscorpius italicus (Chelicerata, Scorpiones, Euscorpiidae)

• Published in: Arthropod structure & development 2014-07, Vol.43 (4), p.361-370
• Main Authors: Jędrzejowska, Izabela, Szymusiak, Kamil, Mazurkiewicz-Kania, Marta, Garbiec, Arnold
• Format: Article
• Language: English
• Subjects: Animals; Arthropoda; Cell Differentiation; Cell–cell adhesion; Chelicerata; Chelicerate type ovary; Epithelial morphogenesis; Euscorpiidae; Euscorpius italicus; Female; Follicular cells; Microscopy, Electron, Transmission; Nymph - anatomy & histology; Nymph - growth & development; Nymph - ultrastructure; Oocytes - cytology; Oocytes - growth & development; Ovary - anatomy & histology; Ovary - growth & development; Ovary - ultrastructure; Scorpiones; Scorpions - anatomy & histology; Scorpions - growth & development; Scorpions - ultrastructure; Stalk cells; Uterus - anatomy & histology; Uterus - growth & development; Uterus - ultrastructure
• ISSN: 1467-8039; 1873-5495
• DOI: 10.1016/j.asd.2013.11.004

In apoikogenic scorpions, growing oocytes protrude from the gonad (ovariuterus) and develop in follicles exposed to the mesosomal (i.e. hemocoelic) cavity. During subsequent stages of oogenesis (previtellogenesis and vitellogenesis), the follicles are connected to the gonad surface by prominent somatic stalks. The aim of our study was to analyze the origin, structure and functioning of somatic cells accompanying protruding oocytes. We show that these cells differentiate into two morphologically distinct subpopulations: the follicular cells and stalk cells. The follicular cells gather on the hemocoelic (i.e. facing the hemocoel) surface of the oocyte, where they constitute a cuboidal epithelium. The arrangement of the follicular cells on the oocyte surface is not uniform; moreover, the actin cytoskeleton of these cells undergoes significant modifications during oocyte growth. During initial stages of the stalk formation the stalk cells elongate and form F-actin rich cytoplasmic processes by which the stalk cells are tightly connected to each other. Additionally, the stalk cells develop microvilli directed towards the growing oocyte. Our findings indicate that the follicular cells covering hemocoelic surfaces of the oocyte and the stalk cells represent two distinct subpopulations of epithelial cells, which differ in morphology, behavior and function. •In the apoikogenic ovariuterus, oocyte growth is accompanied by follicle and stalk cells.•Follicular and stalk cells originate from epithelial cells of the ovariuterus.•Stalk cells form non-tubular stalks.•Follicular and stalk cells differ in position, morphology, behavior and function.•Stalk cells share some features with follicular cells.