Ribonucleic acid biosynthesis in adult and infant rat brain in vitro

The rate of biosynthesis of ribonucleic acid (as judged by the rate of incorporation of uridine into ribonucleic acid) in infant and adullt rat brain cortex slices, incubated (aerobically in tile presenice of various substrates, is directly proportionial to the adenosine triphosphate concentration. This suggests that the adenosine triphosphate concentration is one of the factors involved in the control of ribonucleic acid biosynthesis in infant and adult rat brain. Acetoacetate or beta-hydroxybutyrate is about 70 percent as effective as glucose, with both infant and adult brain, for the promotion of ribonucleic acid biosynthesis. but they are considerably mnore effective than succinate in infant brain than in adult brain.

Protein components in the 40s ribonucleoprotein particles in Escherichia coli

The 40S ribonucleoprotein particle in Escherichia coli cells, accumulated in the presence of a low concentration of chloramphenicol, lacks at least four ribosomal structural protein components which are present in the mature 50S ribosomal subunit. The 40S ribonucleoprotein prepared by exposing the 50S ribosomal subunit to a concentrated lithium chloride solution may also be deficient in the same protein components.

Effects of sodium phenylpyruvate on amino acid formation in brain

Rat brain cortex slices were incubated with glucose-U-C14in normal Krebs–Ringer phosphate media and also media 105 mM in potassium ions. Intracellular labelling of amino acids, such as glutamic acid, glutamine, γ-aminobutyric acid, aspartic acid, and alanine, was estimated by radioautography according to the method of Kini and Quastel. The respiration of brain cortex slices was little affected by the presence of phenylpyruvate. However, the formation of these amino acids was strongly suppressed. Moreover, in high-potassium media, the inhibitory effects of phenylpyruvate were greatly magnified. The addition of phenylalanine had no significant effect either on the oxygen consumption or on the amino acid formation when brain cortex slices were incubated with glucose-U-C14.