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عنوان فارسی مقاله:
اپیتلیوم روده در پوست اندازی کرم ابریشم : تعادل ظریف میان رشد سلول، تمایز و بقا
عنوان انگلیسی مقاله:
Midgut epithelium in molting silkworm: A fine balance among cell growth, differentiation, and survival
222222
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مقدمه انگلیسی مقاله:
1. Introduction
In insects, postembryonic development is characterized by alternating between feeding and molting stages, the latter culminating in ecdysis. During this process, the insect loosens the connections between its living tissues and the extracellular cuticle, escapes from it, takes up water or air to expand the new, flexible exoskeleton, and then quickly hardens it for purposes of defense and locomotion (Wigglesworth, 1972). This is a life-threatening process since a failure in the sequence of events, which are triggered by hormones and involve the coordinated expression of a wide array of genes, can result in the insect's death (Riddiford et al., 2003; Zhao et al., 2006). Together with the growth that occurs during the intermolt period, the gain in size during the intramolt phase (molt increment) also contributes to the growth of the insect body (Gullan and Cranston, 2014). In insects, different types of stem cells are recruited during molting to promote the growth and remodeling of the larval organs (Corley and Lavine, 2006). In this context, the larval midgut of holometabolous insects is no exception. The alimentary canal of the larva is subdivided into three major regions, namely, the foregut, the midgut, and the hindgut, which have different functional roles in feeding and digestion. The foregut is primarily responsible for food ingestion and storage, the hindgut is implicated in the osmotic regulation of internal fluids, while the midgut is involved in nutrient digestion and absorption (Dow, 1986). In lepidopteran larvae, the midgut consists of a monolayered epithelium essentially formed by columnar cells, which produce digestive enzymes and absorb nutrients, and goblet cells, which are involved in ion transport (Terra and Ferreira, 2005). Two other cell types are found in the midgut, namely, endocrine and intestinal stem cells (ISCs). Endocrine cells are sparse in the epithelium and produce the gastrointestinal hormones needed to control the production and secretion of digestive enzymes and for proliferation and differentiation of ISCs (Sehnal and Zitnan, 1996; Rost-Roszkowska et al., 2008). ISCs reside on the basal lamina that supports the epithelium, among columnar and goblet cells. ISCs repair the damaged midgut by replacement in order to maintain the functional integrity of the tissue (Smagghe et al., 2005; Hakim et al., 2010). In addition to the repair function, ISCs proliferate extensively at each larvaelarva molt and then intercalate between the mature cells, differentiating into columnar and goblet cells (Baldwin and Hakim, 1991b; Baldwin et al., 1996). A third role of ISCs is to generate a new functional midgut at larvaepupa molting, which is maintained up to the adult stage (Tettamanti et al., 2007a; Franzetti et al., 2015). In the last few decades, studies on cultured stem cells derived from the midgut of different lepidopteran species have provided insights into the factors that control proliferation and differentiation of these cells (Smagghe et al., 2003; Blackburn et al., 2004; Loeb et al., 2004; Smagghe et al., 2005). This work yielded important information about the setup of midgut primary cultures (Casartelli et al., 2007; Hakim et al., 2009) and their use as a tool to study the physiological properties of midgut cells in vitro (Casartelli et al., 2008). While the in vitro investigation reported above has helped us to better understand some of the regulatory mechanisms involved in the proliferation and differentiation of ISCs, in vivo studies are scarce. In particular, although the behavior of these stem cells during the larvaepupa transition has been characterized in detail (Uwo et al., 2002; Tettamanti et al., 2007a, 2008; Franzetti et al., 2012; Franzetti et al., 2015), only little information is available on ISCs during the larvaelarva molting phase and, more in general, on the events occurring in the larval midgut epithelium during this larval developmental process (Baldwin and Hakim, 1991a, 1991b; Baldwin et al., 1993). Moreover, it is worthy of note that a proteomic study performed in Helicoverpa armigera molting larvae did not identify any obvious, differentially expressed protein spots in the midgut, thus suggesting that minor metabolic changes occur in this organ during larvaelarva molt (Zhao et al., 2006). This evidence undoubtedly adds further complexity to the analysis of the whole organ. This lack of, or only fragmentary knowledge could hinder the full exploitation of lepidopteran midgut as a model system to study stem cell biology. Furthermore, full characterization of the events that occur in the midgut during larvalelarval molting would provide additional advantages. In particular, during this developmental phase, the insect stops feeding, thus offering an opportunity to study the metabolic processes that are set in motion in this organ by physiological starvation. In the present work (i) we studied the morphology and functional activity of the midgut epithelium of the silkworm, Bombyx mori, during larvaelarva molting (IV to V larval instar), focusing our attention on ISCs; (ii) we analyzed the metabolic changes that occur in this organ; and (iii) we evaluated the activation of autophagy, a self-eating process that can be used by eukaryotic cells to cope with nutrient deprivation (He and Klionsky, 2009). To our knowledge, this study represents the first morphological and functional characterization of the changes that occur in the midgut of a lepidopteron during larvaelarva molt. Our results not only provide important insights into the field of stem cell biology, but also represent a useful reference for further studies on molt processes.
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کلمات کلیدی:
[PDF]Midgut epithelium in molting silkworm: A fine balance among cell ... iranarze.ir/wp-content/uploads/2016/10/E1179.pdf In the present study, we analyzed the larval midgut epithelium of the silkworm, Bombyx mori, during larvaelarva molting, focusing our attention on ISCs. A fine balance among cell growth, differentiation, and survival https://www.iris.unina.it/handle/11588/658317 Translate this page by E Franzetti - 2016 - Related articles Titolo: Midgut epithelium in molting silkworm: A fine balance among cell growth, differentiation, and survival. Autori interni: FRANZETTI, ELEONORA Midgut epithelium in molting silkworm: A fine balance among cell ... - خانه www.zoodyab.ir/.../110078-midgut-epithelium-in-molting-silkwor... - Translate this page In the present study, we analyzed the larval midgut epithelium of the silkworm, Bombyx mori, during larva–larva molting, focusing our attention on ISCs. Biology of the Insect Midgut - Page 259 - Google Books Result https://books.google.com/books?isbn=9400915195 M. Lehane, P. Billingsley - 2012 - Science An important question relates to the endocrine control of midgut function in the ... of each instar, remain turned off during the period of moulting, and are restored within ... phosphatase isozymes in the cell surface of silkworm midgut epithelium. Epizootiology of Insect Diseases - Page 82 - Google Books Result https://books.google.com/books?isbn=047187812X James R. Fuxa, Yoshinori Tanada - 1987 - Nature The antiviral activity of the gut juice, therefore, seems to play a minor role in the mechanism of resistance of the silkworm. ... may be one of the major factors preventing virus adsorption to the midgut epithelium. ... It is renewed at each molt. Insect Pathology - Page 307 - Google Books Result https://books.google.com/books?isbn=0080926258 Yoshinori Tanada, Harry K. Kaya, Fernando E. Vega - 2012 - Science by a virus that replicated in the nuclei of midgut epithelial cells and a secondary ... In a molting silkworm larva, the virus-specific polypeptides and mRNA change ... Viral Insecticides for Biological Control https://books.google.com/books?isbn=0323142370 Karl Maramorosch - 2012 - Technology & Engineering In young silkworm larvae the process of midgut infection appears to differ: in— fection ... Moreover, the midgut epithelium of young larvae does not have specific ... The replacement occurs most frequently at the larval molt (Yamaguchi, 1976a).
