The nervous part of the retina of 4 days chicken embryos was disgregated and then it was let to reaggregate by culture in vitro for 28 days. The incomplete development of the photoreceptor outer segments obtained in these experimental conditions was related to the absence of melanic cells of tapetum, which are involved in the metabolism of Vitamin A necessary to the synthesis of the visual pigments localized in the outer segments and which determine their structural organization. In reaggregates of retina with the pigment epithelium, a further differentiation of the outer segments was observed and their characteristically arranged flat sacs or disks were found. Anyway, there was a delay in the differentiation process if compared with that of the controls: at 32 days the aggregates had the same structural organization found in chicken embryos of 17-19 days of age.
Referenze Bibliografiche
BROWN P. K., GIBBONS I. R. e WALD G., «J. Cell Biol.», 19, 79 (1963).
COULOMBRE A. F., «Am. J. Anat.», 96, 153 (1955).
DE ROBERTIS E., «J. Biophys. Biochem. Cytol.», 2 Suppl., 209 (1956).
DOWLING J. E. e GIBBONS I. R., The Structure of the Eye, G. K. Smelser ed., N. Y., Acad. Press, Inc., p. 85 (1961).
EAKIN R.M., «Vision. Res.», 4, 17 (1964).
EAKIN R. M. e WESTFALL J. A., «Embryologia (Nagoya)», 6, 84 (1961).
GRIGNOLO A., «Exp. Eye Res.», 5, 86 (1966).
LASANSKY A. e DE ROBERTIS E., «J. Bjophys. Biochem. Cytol.», 7, 679 (1960).
NILSSON S. E. G., «J. Ultrastr. Res.», 11, 581 (1964).
SJÖSTRAND F. S., «J. Cellular Physiol», 42, 15 (1953).
SORSBY A., READING H. W. e BUNYAN J., «Nature», 210, 1011 (1966).
SORSBY A., KOLLER P. C., ATTFIELD M., DAVEY J. B. e LUCAS D. R., «J. Exp. Zool.», 125, 171 (1954).
STEFANELLI A., ZACCHEI A. M. e CECCHERINI V., «Acta Embriol. Morphol. Exp.», 4, 47 (1961).
STEFANELLI A., ZACCHEI A. M., «Rend. Acc. Naz. Lincei», 30, 818 (1962).
STEFANELLI A., ZACCHEI A. M., CARAVITA S., CATALDI E. e IERALDI L., «Rend. Acc. Naz. Lincei», 40, 758 (1966).
Con il contributo del Ministero per i Beni e le Attività Culturali