SH-SY5Y NEUROBLASTOMA cells were used to study the effect of retinoic acid (RA)-induced differentiation on the expression of gangliosides and neuronal markers. In the presence of 10 μM RA, more than 70% of the cells differentiate to a neuronal phenotype within 8 days. They extend long neuritic processes and show an enhanced immuno-expression of neurone-specific enolase (NSE), neurofilament protein (NF-M), and polysialic acid (PSA). SH-SY5Y cells were found to express at least 12 different gangliosides. RA-induced neuronal differentiation led to a decrease in the content of GM2, GD3, and GD2 and to a 3–7 fold increased concentration of the ganglio-tetraosyl gangliosides GM1, GD1a, GT1a, GD1b, and GT1b. Thus, RA-induced neuronal differentiation of SH-SY5Y cells is accompanied by ganglioside changes similar to those observed during embryonic neuronal differentiation.
In der Oogenese von zwei Floharten tritt in den sekundären Oogonien regelmäßig extrachromo somales DNS-haltiges Material auf. Entstehung und Verhalten wird beschrieben.
Secondary mitotic human skin fibroblast populations in vitro underwent 53 +/- 6 cumulative population doublings (CPD) in 302 +/- 27 days. When the growth capacity of the mitotic fibroblasts is exhausted, and if appropriate methods are applied, the fibroblasts differentiate spontaneously into postmitotic fibroblast populations, which were kept in stationary culture for up to 305 +/- 41 additional days. Mitotic and postmitotic fibroblast populations are heterogeneous populations with reproducible changes in the proportions of mitotic fibroblasts F I, F II, and F III, and postmitotic fibroblasts F IV, F V, F VI, and F VII. This process makes it evident that the fibroblasts differentiate spontaneously along a seven-stage terminal cell lineage F I-F II-F III-F IV-F V-F VI-F VII. Shifts in the frequencies of the mitotic and postmitotic fibroblasts in mass populations are accompanied by alterations in the [35S]methionine polypeptide pattern of the developing mass populations. The [35S]methionine polypeptide patterns of homogeneous subpopulations of F I, F II, F III, F IV, F V, and F VI isolated from heterogeneous mass populations reveal that the six fibroblast morphotypes studied express their cell-type-specific [35S]methionine polypeptide pattern in the heterogeneous mass populations.
