title: Differential effects of culture media on normal and foreign differentiation pathways followed by chick embryo neuroretinal cells in vitro.
abstract: Three different culture media, Ham's F-12, medium 199, and Eagle's minimal essential medium (MEM), were compared with respect to the expression of neuronal (choline acetyl transferase activity: CAT) and glial (hydrocortisone-induced glutamine synthetase activity; GSase) markers of normal differentiation in cultures of 9-day chick embryo neuroretinal cells, and also with respect to the accumulation of a lens marker (delta crystallin) during so-called 'transdifferentiation' in these cultures. MEM allows transient expression of both CAT and GSase activities in early cultures, but also permits extensive delta crystallin accumulation at later stages. F-12 medium gives somewhat higher levels of CAT and GSase activities, the former being noticeably prolonged as compared with parallel MEM cultures; delta crystallin accumulation, however, is largely inhibited in F-12 cultures. By contrast, medium 199 permits only low levels of CAT and GSase activities, perhaps because the neuronal cells are distributed individually over the glial cell sheet in 199 cultures, rather than forming aggregates as in MEM or F-12 cultures. Medium 199 also blocks delta crystallin accumulation. The results of medium changeover between 'transdifferentiation'-permissive (MEM) and non-permissive (199, F-12) conditions suggest: (a) that potential lens precursor cells (whatever their nature) survive in F-12 medium for prolonged periods without extensive expression of the lens phenotype; (b) that such precursor cells become committed to subsequent differentiation as lens cells between 10 and 20 days of culture in permissive MEM medium (as judged by the accumulation of delta crystallin following transfer into F-12); and (c) that medium 199 can block expression of the lens phenotype even in cells already committed (by the above criteria) to lens differentiation, as for instance after 30 days of preculture in MEM.
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002478:Cells, Cultured; D002642:Chick Embryo; D002795:Choline O-Acetyltransferase / Q000378:metabolism; D003459:Crystallins / Q000378:metabolism; D003470:Culture Media; D005974:Glutamate-Ammonia Ligase / Q000378:metabolism; D012160:Retina / Q000166:cytology / Q000196:embryology* / Q000378:metabolism
chemical_list: D003459:Crystallins; D003470:Culture Media; D002795:Choline O-Acetyltransferase; D005974:Glutamate-Ammonia Ligase