Nathans (Nathans), Daniel( American expert in the field of molecular biology, Nobel Prize in Physiology or Medicine, 1978)
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Biography Nathans (Nathans), Daniel
genus. October 30, 1928
American experts in the field of molecular biology, Daniel Nathan, the last of nine children, Sarah (Levitan) and Samuel Nathans, Jewish immigrants from Russia, was born in Wilmington (Delaware). During the economic crisis, his father's work collapsed. Among the earliest memories of Daniela - needs arising from the crisis, and the good humor of his parents in the face of trials.
. Primary education was a boy in public schools in Wilmington, while working part-time after school or on weekends
. In 1946, Mr.. He was enrolled in the University of Delaware, where he studied mathematics, chemistry, philosophy and literature, completing the course in 1950, Mr.. with the degree of Bachelor. Once, in the same year in medical school at Washington University in St. Louis, where classes were highly professional teachers, devoted to science, H. discovered medicine. In one 'perfect summer' under the influence of Oliver Lowry, professor of pharmacology, he decided to study instead of a medical practice start a career as a scientist and teacher. After receiving in 1954. medical degree, he joined the Columbia Presbyterian Medical Center in New York, where he observed the patients 'experienced clinician and medical scientist' Professor Robert Loeb. From 1955 to 1957. N. was an employee of the clinic of the National Cancer Institute (NCI) at the National Institute of Health in Bethesda (Maryland). There he studied the biosynthesis of proteins, in particular myeloma, which is synthesized by malignant plasma cells in multiple myeloma. Returning to Columbia Presbyterian Medical Center, he spent two years on probation again by Loeb. From 1959 to 1962. He was a visiting researcher in the laboratory of Fritz Lipmann at the Rockefeller Institute for Medical Research (now Rockefeller University) in New York. This university H. continued study of the biosynthesis of protein and identified some of the bacterial factors that accelerate the incorporation of amino acids - the building blocks of protein - a protein molecule. Working with a specialist in the field of molecular genetics Norton Zinder, he studied the role of ribonucleic acid (RNA) phages in the synthesis of proteins of phages in the test tube containing the cell extract.
. Genetics and life cycle of bacteriophage were identified in 40-bit and 50-ies
. Bacteriophages (viruses that infect bacterial cells) belong to the simplest forms of life and consist of the inner center of the nucleic acid and the outer protein shell. After penetration into the bacterial cell bacteriophage can continue to develop potential ways. First, he can use the biochemical machinery of the bacterial cells and release new phage particles, causing the destruction of cells. Secondly, it is possible to incorporate it into the genetic structure of cells, or deoxyribonucleic acid (DNA) (in this case is called a bacteriophage prophage), and further transfer to daughter cells during bacterial cell division. Third, the enzyme system of bacteriophage can decompose into its component parts under the influence of bacterial enzymes - a phenomenon known as 'induced host cell variation', or 'restriction-modification'.
. Restrikatsiya-modification carried a pair of enzymes of the bacterial cell, restriction endonuclease and methylase
. Restriction endonuclease defines a specific nucleotide sequence of bacteriophage DNA and cleaves, or cuts, the phage DNA into separate parts. At the same time methylase recognizes identical sequence of nucleotides in the DNA of the host cell, methylates it, and thus protects it from enzymatic cleavage of its own endonuclease. (Methylation involves the addition of a methyl group, consisting of a carbon atom and three hydrogen atoms to a molecule of DNA.)
In 1960, Mr.. Werner Arber, University of Geneva in Switzerland put forward the hypothesis that restriction-modification system are the main characteristics of bacteria. Arber also discovered restriction endonuclease in the intestinal bacterium Escherichia coli. However endonuclease Arber cut the phage DNA in the nonspecific sites. He called it endonuclease I-type and predicted that the site-specific restriction endonucleases are found in other bacterial systems and will be useful for accurate analysis of the genetic structure of DNA molecules.
In 1962. N. is an assistant professor of microbiology and head of the genetic department in medical school at Johns Hopkins. By 1965, Mr.. He reaches the adjunct professor, and two years later - a full professor. During this period, H. continues to examine the replication of bacteriophages in experimental systems, in particular the regulation of replication and the location of genes in DNA and RNA.
In the mid 60-ies. N. lectures to students on animal viruses that are similar to bacteriophages, except for the fact that they infect animal cells. Animal viruses can be infectious or oncogenic, ie. cause tumor. A more detailed study of such viruses H. particularly interested in virus-40 monkeys, . which causes the formation of tumors in monkeys, . and focused on the analysis of localization and function of genes of the virus DNA, . continuing to improve their knowledge on the genetics of animal viruses.,
. In a letter to N., written in 1969, when he, being a Fellow of the American Cancer Society, worked in the Weizmann Institute in Rehovot (Israel), Hamilton ON
. Smith, a colleague at the Institute of the Johns Hopkins University, reported on the isolation and purification of site-specific restriction endonuclease in the bacteria Haemophilus influenzae. This fact was for H. One thing to consider the possibility of using restriction enzymes for cleavage and analysis of the genome (the full nabopa inborn traits) DNA oncogenic viruses. Upon returning to the Institute of the Johns Hopkins University that summer N. a few months studying the genetic structure of DNA virus-40 monkeys, using endonuclease Smith and another, discovered by another researcher.
. DNA virus of monkeys is a suitable subject for study because it is small, consists of 5 thousand
. nucleotides (one of the components, which falls under the influence of nuclease nucleic acid) and includes several genes. N. and his colleagues first split the DNA molecule with two endonucleases, identified the individual parts and created a map of places of splitting. Then they set the line localization and function of specific genes and developed the first detailed genetic map of the DNA molecule, including sites (sites) beginning and end of the process of replication. (Since the DNA molecule of the virus of monkeys is circularly, . replication occurs in two directions around the circular DNA and ends at 180 б° from the start site of replication.) Scientists have also determined the nucleotide matrix for the mRNA and localization of genes, . directing the synthesis of protein shell of the virus, . using the selected mutant strain of monkeypox DNA to analyze the localization of some genes and their functions,
. Developed H. methods of analysis of genetic structure were later used for genetic mapping of more complex molecules of DNA, . and to develop methods of recombinant DNA to create a bacterial 'factories', . synthesizing the necessary preparations for medicine, . such, . as insulin and growth hormones.,
. shared the Nobel Prize in Physiology or Medicine 1978. with Arber and Smith for the 'discovery of enzymes restrikatsii and methods of their use for research in molecular genetics'. In his Nobel lecture H. described the study of virus-40 monkeys. 'Eventually, . - He concluded, . - Will be possible understanding of the basic regulatory mechanisms, . used by cells of plants and animals, . and ultimately the realization of some complex genetic programs, . managed growth, . development and specialized functions of higher organisms, . including man.,
. Since 1980
. N. - Professor of Molecular Biology and Genetics in medical school at Johns Hopkins and a senior researcher at the Medical Institute Howard Hug.
In 1956, Mr.. N. married Joan Komberg; they had three sons. 'My research is concerned with me, as always, - said H. - I have talented students, which causes a feeling of great satisfaction, "and I expect them to great success in the future."
Among the awards H. - Prize for Molecular Biology of the National Academy of Sciences (1976). He - a member of the American Academy of Arts and Sciences.