[RNA biosynthesis and regulation of protein biosynthesis in the liver of chicks with experimental coccidiosis].

The aim of this work was to investigate the interrelationship between RNA biosynthesis and that of protein in chick liver during experimental coccidiosis induced by E. tenella. The peculiarity of this model is that in the course of this disease protein synthesis is significantly intensified inspite of the fact that the rate of the biosynthesis is rather high under normal conditions. It has been shown that 4 to 6 days after infection incorporation of labeled amino acids into proteins from chick liver subcellular fractions is greatly increased. The most pronounced changes are in ribosomal and mitochondrial fractions as well as in the postribosomal supernatant. At the same time the specific radioactivity of serum albumin excreted by liver was increased by factor 3. These changes in protein biosynthesis are associated with a significant increase of both the content and intensity of biosynthesis of high molecular weight precursors of rRNA as well as with those of mature 18S rRNA. The amount of 28S rRNA and mRNA per cell is practically without any changes whereas the mRNA turnover is somewhat more extensive. The selective accumulation of 18S rRNA is suggested to be responsible for the intensification of protein biosynthesis.