sparsomycin and Carcinoma--Ehrlich-Tumor

Topics: Animals; Antibiotics, Antineoplastic; Carcinoma, Ehrlich Tumor; Mice; Sparsomycin; Structure-Activity Relationship

The effect of a number of inhibitors of protein synthesis on ppGpp and pppGpp synthesis in vitro has been examined. As expected from in vivo results, chloramphenicol is without effect on this reaction. Aurintricarboxylic acid and chlortetracycline, on the other hand rapidly and specifically inhibit ppGpp synthesis. Fusidic acid in the presence of saturating amounts of EF G also inhibits the reaction completely, suggesting that an empty ribosomal acceptor site is necessary for this reaction. On the other hand, the 50-S subunit proteins L7 and L12 are not required for stringent factor activity. Ribosomes from Pseudomonas fluorescens can replace those from Escherichia coli in the complete system, while ribosomes from Ehrlich ascites cannot. A small but reproducible synthesis of ppGpp is observed when the ribosomal wash from E. coli is complemented with ribosomes from wheat germ cytoplasm.

Topics: Animals; Carcinoma, Ehrlich Tumor; Chloramphenicol; Chlortetracycline; Escherichia coli; Fusidic Acid; Guanine Nucleotides; Mice; Peptide Biosynthesis; Phenylalanine; Plants; Pseudomonas fluorescens; Puromycin; Ribosomes; Sparsomycin; Species Specificity; Time Factors; Transcription, Genetic

With mRNA prepared from induced human fibroblasts biologically active human interferon was synthesized de novo in a cell-free extract from mouse cells. The identity of the antiviral activity as human interferon was demonstrated by its species and antigenic specificity.

Topics: Animals; Carcinoma, Ehrlich Tumor; Chickens; Cycloheximide; Fibroblasts; Humans; Interferons; Mice; Poly I-C; Protein Biosynthesis; RNA, Messenger; Sparsomycin; Species Specificity