Strominger’s laboratory and subsequently in Dr. Luckily, our discovery of the novel nucleotide sugar compound provided us with an opportunity to work in Dr. Kornberg’s laboratory at Stanford University could afford such research environment. Only a few privileged laboratories such as Dr. It was impossible for us to study mechanisms of DNA synthesis in vitro, since even radioactive substrates were not commercially available then and should be prepared by ourselves and we didn’t have enough technologies for that. In retrospect, such kinetic analyses of conversion from -thymidine to nucleotide and DNA in vivo by pulse labeling experiment later served our strong background for the analyses of synthetic reactions at replication forks and lead to the discovery of the discontinuous mechanism of DNA synthesis. coli cells detected first in nucleosides, then in TMP, TDP, and TTP in this order, and about 20 seconds after the administration to the culture medium it began to be detected in DNA fraction and accumulated with time in it. When -thymidine became available for us, we traced the fate of -thymidine added to the culture medium of Escherichia coli cells. 4) Later on, we began to conduct experiments with bacteria and Escherichia coli became the favorite experimental materials. We could recover various nucleotides from the column and fortunately enough discovered a novel sugar-linked nucleotide which was identified to be thymidine-diphosphate rhamnose. A fraction collector driven by balancing mechanism was our important instrument which we bought with our pocket money. We extracted nucleotides from those eggs with ice cold TCA solution, purified by charcoal treatments and then separated by column chromatography. Eggs of sea urchins and frogs were popular materials in the Developmental Biology Laboratory we belonged to then. We thought that unfertilized eggs must store high level of nucleotides required for rapid syntheses of DNA and RNA for the cleavage stage after fertilization. Reiji and I decided to analyze nucleotides in sea urchin and frog eggs. We could expect little financial support, if any, for research from the government. 3) Since buildings of Nagoya University were burned down during the war, laboratories were in a barrack and libraries equipped not enough journals from abroad so that we had to visit American Cultural Center to read them. They demonstrated that polynucleotide chains complementary to the template DNA were synthesized with deoxyribonucleoside-5′triphosphates (dNTPs) in reaction mixtures. coli (now called DNA polymerase I) was reported by Arthur Kornberg and the basic concepts and technologies to study DNA biosynthesis seemed to be established by his colleagues. In 1956, discovery of DNA polymerase of E. I remember the surprise when I read Watson and Crick’s paper on the structure of DNA, which even explained the semi-conservative DNA replication and genetic phenomena solely by the principles of physical chemistry, although no biochemical mechanisms were there. In 1956, when I entered graduate school of Nagoya University, Institute Molecular Biology, I got married with Reiji Okazaki (1930–1975). Japanese universities as well as society in general were still suffering the damages received during the war time in those days. 2) Thus, my research career overlaps with the history of Molecular Biology. The Hershey-Chase experiment was reported when I was a freshman 1) and the next year double helical model of DNA was proposed. I was admitted to study at Nagoya University, School of Science in 1952 and majored Biology. Thus, I became the first generation Japanese women who received coeducation with man in high schools and universities. In 1945, when I was in the sixth grade of elementary school, Japan was defeated in the World War II, and few years later new Japanese Constitution declared equal rights for women and men under the law. Prologue: Days before the research on DNA replication
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