Niacin Biosynthesis in the Developing Chick Embryo

Niacin biosynthesis in the developing chick embryo.

In 1945, Krehl et al. (1) observed that tryptophan and nicotinic acid were mutually interchangeable, within limits, in supporting the growth of rats. Since that time considerable evidence has accumulated which demonstrates the biosynthesis of niacin from tryptophan in the rat and other animals. Studies with Neurospora and mammals have demonstrated that the pathway from tryptophan goes through k...

The Developing Chick Embryo

The RNA-P and DNA-P content of the nucleus and the RNA-P content of the whole cell of the livers of 8to 20-day chick embryos and of adult fowls have been determined. The DNA-P content of the liver nuclei was slightly higher in the 8and 10-day embryo than in all the other stages examined. A significant decrease in the RNA content of the cell occurred during embryonic development. The RNA content...

Glutamic dehydrogenase in the developing chick embryo.

1. The behaviour of serum albumin and yglobulin labelled with 131I has been investigated in the isolated perfused rat liver. 2. Such a liver has been found capable of preferentially removing and then breaking down very small proportions of altered protein molecules present in preparations of plasma proteins isolated by the usual methods. The proportions of such altered molecules actually presen...

Bacteriophagy in the Developing Chick Embryo.

Elastin biosynthesis in chick-embryo arteries

Electrophoretic analyses of the products of cell-free translation of elastin mRNA isolated from 17-day chick-embryo thoracic arteries have demonstrated that the elastin mRNA codes for polypeptides that are slightly larger than the cellular tropoelastin polypeptides synthesized and secreted by matrix-free artery cells. Pulse-chase experiments with cells labelled with [3H]proline established that...