caa a22 4500 469081880 CHVBK 20180323132952.0 cr unu---uuuuu 170328e19920601xx s 000 0 eng 10.1007/BF00319160 doi (NATIONALLICENCE)springer-10.1007/BF00319160 Biogenesis of myeloid bodies in regenerating newt ( Notophthalmus viridescens ) retinal pigment epithelium [Elektronische Daten] [Daniel Abran, D. Dickson] Summary: Myeloid bodies are believed to be differentiated areas of smooth endoplasmic reticulum membranes, and they are found within the retinal pigment epithelium in a number of lower vertebrates. Previous studies demonstrated a correlation between phagocytosis of outer segment disc membranes and myeloid body numbers in the retinal pigment epithelium of the newt. To test the hypothesis that myeloid bodies are directly involved in outer segment lipid metabolism and to further characterize the origin and functional significance of these organelles, we examined the effects on myeloid bodies of eliminating the source of outer segment membrane lipids (neural retina removal) and of the subsequent return of outer segments (retinal regeneration) in the newt Notophthalmus viridescens. Light- and electron-microscopic analysis demonstrated that myeloid bodies disappeared from the pigment epithelium within six days of neural retina removal. By week 6 of regeneration, rudimentary photoreceptor outer segments were present but myeloid bodies were still absent. However, at this time, the smooth endoplasmic reticulum in some areas of the retinal pigment epithelial cells had become flattened, giving rise to small (0.5 μm long), two-to-four layer-thick lamellar units, which are myeloid body precursors. Small myeloid bodies were first observed one week later at week 7 of retinal regeneration. This study revealed that newt myeloid bodies are specialized areas of smooth endoplasmic reticulum. It also showed that a contact between functional photoreceptors and the retinal pigment epithelium is essential to the presence of myeloid bodies in the epithelial cells. Springer-Verlag, 1992 Retinal pigment epithelium nationallicence Myeloid bodies nationallicence Regeneration nationallicence Notophthalmus viridescens (Urodela) nationallicence Abran Daniel Department of Anatomy, Dalhousie University, B3H 4H7, Halifax, Nova Scotia, Canada aut Dickson D. Department of Anatomy, Dalhousie University, B3H 4H7, Halifax, Nova Scotia, Canada aut Cell and Tissue Research Springer-Verlag 268/3(1992-06-01), 531-538 0302-766X 268:3<531 1992 268 441 https://doi.org/10.1007/BF00319160 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00319160 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Abran Daniel Department of Anatomy, Dalhousie University, B3H 4H7, Halifax, Nova Scotia, Canada aut NATIONALLICENCE 700 1- Dickson D. Department of Anatomy, Dalhousie University, B3H 4H7, Halifax, Nova Scotia, Canada aut NATIONALLICENCE 773 0- Cell and Tissue Research Springer-Verlag 268/3(1992-06-01), 531-538 0302-766X 268:3<531 1992 268 441 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer