A fraction of the ultrafilterable portion of chick embryo extract was isolated by alcohol extraction of a lyophilized powder of the ultrafiltrate followed by ion exchange removal of many of the inert components of the alcohol extract. This fraction contained 3 per cent of the ultrafilterable nitrogen but was capable of completely restoring the growth-promoting activity of dialyzed embryo extract, when tested with chick heart fibroblasts in roller tube cultures. The low nitrogen content, shape of the ultraviolet absorption spectrum, and presence of few free amino acids, suggest that non-dialyzable compounds serve as the chief source of nutrition for this system.

Animals↗

PubMed1953

Tissue culture studies; identification of components and synthetic replacements for the active fraction of chick embryo extract ultrafiltrate.

Some of the compounds in the active fraction of ultrafiltrates of chick embryo extract have been identified as taurine, serine, glutamic acid, xanthine, uracil, glucose-6-phosphate, glucose, ferrous iron, and inorganic phosphate. Based on the identity of these compounds a synthetic replacement for the ultrafilterable portion of chick embryo extract has been devised. There is an additional nutritional requirement that can be met by vitamin B(12). Folic acid appears to be beneficial to the system though the requirements of this or any of the above compounds except vitamin B(12) remain for future research. The low nitrogen content of the isolated fraction and the synthetic mixture suggests that the main nutrition of chick cells in roller tube cultures is derived from the non-dialyzable portion of the medium.

Animals↗

PubMed1953