English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The production of individual serum proteins by individual kinds of tissue is difficult to prove or to disprove in experiments with intact animals or with surviving organs, since these contain a multitude of different kinds of tissue, often of overlapping activities and capable of mutual interaction. It is therefore preferable to investigate uniform tissue in isolation, i.e. in culture. Such tissue proliferates, in principle, indefinitely. Its biochemical potentialities presumably do not exceed those of the same kind of tissue in vivo, though they might be more restricted; thus the positive proof that a particular protein is synthesized by tissue in culture indicates that such synthesis may also proceed in vivo. Intact animals or surviving organs are impregnated with fluids containing serum proteins, e.g. blood. It is therefore necessary when using them in experiments on protein synthesis to distinguish between pre-existing protein and newly synthesized protein. This can be done by the use of labelled amino acids, when only the newly formed protein will contain the label. Even in experiments with tissue cultivated in a medium originally free of serum proteins, however, the distinction between preformed and newly formed proteins is still needed in view of the protein contents of the cells themselves. For this reason, the use of isotopes is almost indispensable in this case as well. Moreover, the use of radioactive isotopes gives a method where the sensitivity of measurement is very high. Three kinds of tissue were used for our experiments, namely mesenchyma tissue from chick embryos, epithelial-tumour HeLa tissue and a transformed human-liver-cell strain HLM. The tissue was incubated with nutrient medium containing [14C]amino acid, and subsequently the soluble proteins of the tissue and medium were separated and fractionated by selective precipitation with ethanol. Electrophoresis in starch gel, followed by staining, was carried out as a test for the purity of the fractions. Finally, the radio* On leave from the Clinical Pathology Department, Faculty of Medicine, Alexandria University, Alexandria, Egypt, U.A.R.

The autonomous production of individual serum proteins by tissue in culture