Although some work has been done on the metabolism of the RNA and, to a lesser extent, of the protein in ribosomal particles (Roberts, 1960, 1961, 1962), little is known of their structure. The general physical characteristics of Escherichia coli ribosomes have been studied by Tissieres, Watson, Schlessinger & Hollingworth (1959), of yeast ribosomes by Chao & Schachman (1956), of peaseedling ri...

Ribosomes of physiologically nondividing human peripheral blood lymphocytes were studied by ultraviolet absorbance measurements of cytoplasmic extracts subjected to ultracentrifugation in sucrose gradients at high and low ionic strength. At least 70% of the total cytoplasmic ribosomes were free ribosomes which sedimented at 80 S in low salt and dissociated to 40 S and 60 S subunits in high salt...

Recently, we showed that Schwann cells transfer ribosomes to injured axons. Here, we demonstrate that Schwann cells transfer ribosomes to regenerating axons in vivo. For this, we used lentiviral vector-mediated expression of ribosomal protein L4 and eGFP to label ribosomes in Schwann cells. Two approaches were followed. First, we transduced Schwann cells in vivo in the distal trunk of the sciat...

1. Ribonuclease II of Escherichia coli degrades pulse-labelled RNA associated with ribosomes and polyuridylic acid on ribosomes and in solution to mononucleotides. 2. Ribosomal and pulse-labelled RNA in solution and ribosomal RNA in chloramphenicol particles (protein-deficient ribosomes) are degraded to oligonucleotides. 3. Ribosomal RNA in mature ribosomes is not attacked by the enzyme. 4. Fro...

The chloroplast ribosomes from five antibiotic resistant strains of Chlamydomonas, each carrying one mutant gene mapping in chloroplast DNA, have been shown to be resistant to the corresponding antibiotic in a poly(U)-directed amino-acid incorporating assay system. The alteration conferring resistance was localized to the 30S subunit in ribosomes from streptomycin, neamine, and spectinomycin re...

Membrane-bound and free ribosomes were prepared by discontinuous density gradient centrifugation from livers of rats 2-3 days after receiving alloxan (75 mg/kg) or streptozotocin (100 mg/kg). Hepatocytes from these animals were also examined by electron microscopy and subjected to quantitative morphometric analysis. The results indicated that the two populations of hepatic ribosomes respond dif...

We developed orthogonal ribosome-mRNA pairs in which the orthogonal ribosome (O-ribosome) specifically translates the orthogonal mRNA and the orthogonal mRNA is not a substrate for cellular ribosomes. O-ribosomes have been used to create new cellular circuits to control gene expression in new ways, they have been used to provide new information about the ribosome, and they form a crucial part o...