It is demonstrated that newborn rat retinal photoreceptor cells can differentiate in monolayer culture, and synthesize de novo photoreceptor‐specific proteins such as opsin. When maintained in serum supplemented medium on a laminin substrate, these cells survive for up to 3 weeks. The addition of acidic fibroblast growth factor stimulates an increase in the levels of opsin of 5–10‐fold control values, and prolongs cell survival by up to 6 days.
We examined the effect of basic fibroblast growth factor (FGF) on phosphorylation and lipocortin-like activity of the 34 kDa protein present in the basal membrane of epithelial peripheral cells which initiate growth and differentiation in the bovine lens. We found that: (i) the 34 kDa protein possesses anti-phospholipase A2 (PLA2) activity of lipocortin; (ii) in response to FGF, the anti-PLA2 activity of this protein is enhanced whereas its phosphorylation is markedly decreased. It is suggested that the 34 kDa protein might represent an important biological activity in controlling FGF induction of growth and differentiation in the adult eye lens.
The electrophoretic patterns of 35S-methionine-labelled proteins from long-term cultured adult bovine epithelial lens (BEL) cells and of primary calf myotube cultures were compared using two-dimensional gel electrophoresis. In the pH and molecular weight range examined, the two patterns differ in a number of polypeptide species. Desmin as well as other specific muscle proteins were absent in BEL cells but both cell types shared the same cytoskeletal proteins such as the α-, β-tubulins, β- and γ-actin and vimentin. The effect of a retinal extract on the morphology of BEL cells in culture has been previously described and was further studied here. Depending on the culture conditions and on the presence or absence of RE, we were able to induce and control three morphologically very distinct shapes of the same BEL cells.
This paper summarises a conceptual discussion of some aspects of biomarkers of aging and the logical strategy for developing them. A biomarker of aging is a biological parameter of an organism that either alone or in some multivariate composite will, in the absence of disease, better predict functional capability at some late age than with chronological age. The criteria for putative biomarker measurement and assessment of putative biomarkers are discussed.
quelque manière que ce soit, est interdite sauf accord préalable et écrit de l'éditeur, en dehors des cas prévus par la législation en vigueur en France.Il est précisé que son stockage dans une base de données est également interdit.
