V PLASTIC BOMBS IN PARIS ye POLICE MEDICS ON RUN See Page 2 / 1 Medical Tribune Vol. 3, No. 13 ©1962, Medical Tribune, Inc. er Experts Challenge, Support Nucleic Acid ‘Code’ Concepts Medical Tribune Photo-—-Roy Stevens ! Nobel Laureate Dr, Severo Ochoa, New York University, leads session at symposium | on neoplasms marking Columbia University, Francis Delafield Hospital anniversaries. ' Medical Tribune—World Wide Report New York—Current concepts concerning the chemical code of inheritance, and the role of nucleic acids in directing the manufacture of proteins from specific amino acid sequences, were challenged—and as vigorously defended—at a sym- . posium here. The symposium, “Basic Problems in Neoplastic Disease,” was spon- sored by Columbia University College to be true on the basis of present experi- | Chargaff observed, : they can carry it alone.” of Physicians and Surgeons. Dr. Erwin Chargaff, Columbia Profes- sor of Bioc! cmistry, cite cited with consider- SYMPOSIUM ON . NEOPLASTIC DISEASES Nucleic Acids and Protein Synthesis. Genetic Coding of Amino Acids. Studies of Neoplastic Transformation. able skepticism the prevailing view that genetic instructions controlling the ar- rangement of amino acids along the pro- tein molecule are encoded in the structure of DNA in the cell nucleus and trans- mitted by an RNA “messenger” to the ri- bosomes where protein is synthesized. The postulation that such a chain of biologic information universally exists and Continued on page 21 world news of medicine and its practice—fast, accurate, complete Monday, March 26, 1962 Continued from page I is transmitted in this manner through the — “entire realm of life” cannot be assumed mental evidence, Dr. Chargaff said. He ex- pressed doubt that principles derived pri- marily from studies of lower forms of life such as phages and viruses could be prop- erly supplied to higher forms “about which astonishingly little is now known.” The nucleic acids “now seem to play the role played by the philosopher’s stone in the alchemy of the Middle Ages,” Dr, “and I am not sure “A Fairy Tale Picture’ bm In comment, Dr. Severo Ochoa, New | York University Professor of Biochemis- try, one of the principal investigators who : have been working on deciphering the genetic code, noted his agreement with Dr. Chargaff that “modern genetics, enzymol- ogy, and molecular biology have indeed painted a fairy tale picture of the events under discussion. However, I do not share his skepticism as to the accuracy of this picture.” It was the work of Dr.-Ochoa and col- leagues at New York University, proceed- ing along similar lines as investigators at the National Institutes of Health, that led some months ago to their determination of the nucleic acid coding for the amino acid phenylalanine and subsequently to codes for all 20 amino acids. In these studies, a synthetic RNA tem- plate made with the enzyme polynucleo- tide phosphorylase and composed entirely of uracil bases produced a protein consist- ing only of phenylalanine. Later, small amounts of other nucleic acid bases were . added to the synthetic RNA, the resultant: protein was compared with the original‘ protein produced, and code letters were assigned to the other amino acids. In support of the coding system as | worked out thus far, Dr. Ochoa cited studies of tobacco mosaic virus in which mutation induced by treatment with HNO, produced changes in amino acid components. The changes correlated “very — well” with the code letter assignments, Dr. Ochoa said. In his report Dr. Chargaff emphasized apparent discrepancies between the known chemical composition of certain proteins and the postulated coding system. For example, in the case of bovine ribonu- ‘ clease and salmine, he calculated the com- ' ponents of messenger RNA that “should have coded” for these proteins and found a ‘very bizarre” pattern. Two Messenger Chains Needed Moreover, a “main unsolved problem,” according to Dr. Chargaff, is that “if there really is a messenger RNA which is sup- posed to reflect the composition of DNA, one must assume the existence of two chains of messenger RNA since DNA is a double-stranded molecule.” Yet current theory holds that only one strand of RNA codes for protein, Dr. Chargaff noted. m At another symposium session, Dr. Renato Dulbecco, of the California Insti- tute of Technology, advanced his hypoth- esis, based on studies of virus-induced tumors, that the process of neoplastic transformation involves different mecha- nisms depending on whether the virus con- tains principally RNA or DNA. Studies with Rous sarcoma, produced by an RNA virus, indicate that the continuously replicating virus produces changes in the cell surface and antigenic structure that are characteristic findings in neoplastic cells. In the case of polyoma, containing a | DNA virus, the virus affects the nucleus ; and the mitotic system rather than syn- | thetic processes within the cell. Evidence - indicates that the virus either attaches to the genes within the cell or itself induces a mutation, Dr. Dulbecco said. '