Harvard University is a private Ivy League research university in Cambridge, with about 6,700 undergraduate students and about 15,250 postgraduate students. Established in 1636 and named for its first benefactor, clergyman John Harvard, Harvard is the United States' oldest institution of higher learning, its history and wealth have made it one of the world's most prestigious universities; the Harvard Corporation is its first chartered corporation. Although never formally affiliated with any denomination, the early College trained Congregational and Unitarian clergy, its curriculum and student body were secularized during the 18th century, by the 19th century, Harvard had emerged as the central cultural establishment among Boston elites. Following the American Civil War, President Charles W. Eliot's long tenure transformed the college and affiliated professional schools into a modern research university. A. Lawrence Lowell, who followed Eliot, further reformed the undergraduate curriculum and undertook aggressive expansion of Harvard's land holdings and physical plant.
James Bryant Conant led the university through the Great Depression and World War II and began to reform the curriculum and liberalize admissions after the war. The undergraduate college became coeducational after its 1977 merger with Radcliffe College; the university is organized into eleven separate academic units—ten faculties and the Radcliffe Institute for Advanced Study—with campuses throughout the Boston metropolitan area: its 209-acre main campus is centered on Harvard Yard in Cambridge 3 miles northwest of Boston. Harvard's endowment is worth $39.2 billion, making it the largest of any academic institution. Harvard is a large residential research university; the nominal cost of attendance is high, but the university's large endowment allows it to offer generous financial aid packages. The Harvard Library is the world's largest academic and private library system, comprising 79 individual libraries holding over 18 million items; the University is cited as one of the world's top tertiary institutions by various organizations.
Harvard's alumni include eight U. S. presidents, more than thirty foreign heads of state, 62 living billionaires, 359 Rhodes Scholars, 242 Marshall Scholars. As of October 2018, 158 Nobel laureates, 18 Fields Medalists, 14 Turing Award winners have been affiliated as students, faculty, or researchers. In addition, Harvard students and alumni have won 10 Academy Awards, 48 Pulitzer Prizes and 108 Olympic medals, have founded a large number of companies worldwide. Harvard was established in 1636 by vote of the Great and General Court of the Massachusetts Bay Colony. In 1638, it acquired British North America's first known printing press. In 1639, it was named Harvard College after deceased clergyman John Harvard, an alumnus of the University of Cambridge, who had left the school £779 and his scholar's library of some 400 volumes; the charter creating the Harvard Corporation was granted in 1650. A 1643 publication gave the school's purpose as "to advance learning and perpetuate it to posterity, dreading to leave an illiterate ministry to the churches when our present ministers shall lie in the dust".
It offered a classic curriculum on the English university model—many leaders in the colony had attended the University of Cambridge—but conformed to the tenets of Puritanism. It was never affiliated with any particular denomination, but many of its earliest graduates went on to become clergymen in Congregational and Unitarian churches; the leading Boston divine Increase Mather served as president from 1685 to 1701. In 1708, John Leverett became the first president, not a clergyman, marking a turning of the college from Puritanism and toward intellectual independence. Throughout the 18th century, Enlightenment ideas of the power of reason and free will became widespread among Congregational ministers, putting those ministers and their congregations in tension with more traditionalist, Calvinist parties; when the Hollis Professor of Divinity David Tappan died in 1803 and the president of Harvard Joseph Willard died a year in 1804, a struggle broke out over their replacements. Henry Ware was elected to the chair in 1805, the liberal Samuel Webber was appointed to the presidency of Harvard two years which signaled the changing of the tide from the dominance of traditional ideas at Harvard to the dominance of liberal, Arminian ideas.
In 1846, the natural history lectures of Louis Agassiz were acclaimed both in New York and on the campus at Harvard College. Agassiz's approach was distinctly idealist and posited Americans' "participation in the Divine Nature" and the possibility of understanding "intellectual existences". Agassiz's perspective on science combined observation with intuition and the assumption that a person can grasp the "divine plan" in all phenomena; when it came to explaining life-forms, Agassiz resorted to matters of shape based on a presumed archetype for his evidence. This dual view of knowledge was in concert with the teachings of Common Sense Realism derived from Scottish philosophers Thomas Reid and Dugald Stewart, whose works were part of the Harvard curriculum at the time; the popularity of Agassiz's efforts to "soar with Plato" also derived from other writings to which Harvard students
American Academy of Arts and Sciences
The American Academy of Arts and Sciences is one of the oldest learned societies in the United States. Founded in 1780, the Academy is dedicated to honoring excellence and leadership, working across disciplines and divides, advancing the common good. Membership in the academy is achieved through a thorough petition and election process and has been considered a high honor of scholarly and societal merit since the academy was founded during the American Revolution by John Adams, John Hancock, James Bowdoin, others of their contemporaries who contributed prominently to the establishment of the new nation, its government, the United States Constitution. Today the Academy is charged with a dual function: to elect to membership the finest minds and most influential leaders, drawn from science, business, public affairs, the arts, from each generation, to conduct policy studies in response to the needs of society. Major Academy projects now have focused on higher education and research and cultural studies and technological advances, politics and the environment, the welfare of children.
Dædalus, the Academy's quarterly journal, is regarded as one of the world's leading intellectual journals. The Academy carries out nonpartisan policy research by bringing together scientists, artists, business leaders, other experts to make multidisciplinary analyses of complex social and intellectual topics; the Academy's current areas of work are Arts & Humanities, Democracy & Justice, Energy & Environment, Global Affairs, Science & Technology. David W. Oxtoby began his term as the organization’s President in January 2019. A chemist by training, he served as President of Pomona College from 2003 to 2017, he was elected a member of the American Academy in 2012. The Academy is headquartered in Massachusetts; the Academy was established by the Massachusetts legislature on May 4, 1780. Its purpose, as described in its charter, is "to cultivate every art and science which may tend to advance the interest, honor and happiness of a free and virtuous people." The sixty-two incorporating fellows represented varying interests and high standing in the political and commercial sectors of the state.
The first class of new members, chosen by the Academy in 1781, included Benjamin Franklin and George Washington as well as several international honorary members. The initial volume of Academy Memoirs appeared in 1785, the Proceedings followed in 1846. In the 1950s, the Academy launched its journal Daedalus, reflecting its commitment to a broader intellectual and socially-oriented program. Since the second half of the twentieth century, independent research has become a central focus of the Academy. In the late 1950s, arms control emerged as one of its signature concerns; the Academy served as the catalyst in establishing the National Humanities Center in North Carolina. In the late 1990s, the Academy developed a new strategic plan, focusing on four major areas: science and global security. In 2002, the Academy established a visiting scholars program in association with Harvard University. More than 75 academic institutions from across the country have become Affiliates of the Academy to support this program and other Academy initiatives.
The Academy has sponsored a number of awards and prizes, now numbering 11, throughout its history and has offered opportunities for fellowships and visiting scholars at the Academy. Charter members of the Academy are John Adams, Samuel Adams, John Bacon, James Bowdoin, Charles Chauncy, John Clarke, David Cobb, Samuel Cooper, Nathan Cushing, Thomas Cushing, William Cushing, Tristram Dalton, Francis Dana, Samuel Deane, Perez Fobes, Caleb Gannett, Henry Gardner, Benjamin Guild, John Hancock, Joseph Hawley, Edward Augustus Holyoke, Ebenezer Hunt, Jonathan Jackson, Charles Jarvis, Samuel Langdon, Levi Lincoln, Daniel Little, Elijah Lothrup, John Lowell, Samuel Mather, Samuel Moody, Andrew Oliver, Joseph Orne, Theodore Parsons, George Partridge, Robert Treat Paine, Phillips Payson, Samuel Phillips, John Pickering, Oliver Prescott, Zedekiah Sanger, Nathaniel Peaslee Sargeant, Micajah Sawyer, Theodore Sedgwick, William Sever, David Sewall, Stephen Sewall, John Sprague, Ebenezer Storer, Caleb Strong, James Sullivan, John Bernard Sweat, Nathaniel Tracy, Cotton Tufts, James Warren, Samuel West, Edward Wigglesworth, Joseph Willard, Abraham Williams, Nehemiah Williams, Samuel Williams, James Winthrop.
From the beginning, the membership and elected by peers, has included not only scientists and scholars, but writers and artists as well as representatives from the full range of professions and public life. Throughout the Academy's history, 10,000 fellows have been elected, including such notables as John Adams, Thomas Jefferson, John James Audubon, Joseph Henry, Washington Irving, Josiah Willard Gibbs, Augustus Saint-Gaudens, J. Robert Oppenheimer, Willa Cather, T. S. Eliot, Edward R. Murrow, Jonas Salk, Eudora Welty, Duke Ellington. International honorary members have included Jose Antonio Pantoja Hernandez, Leonhard Euler, Marquis de Lafayette, Alexander von Humboldt, Leopold von Ranke, Charles Darwin, Otto Hahn, Jawaharlal Nehru, Pablo Picasso, Liu Kuo-Sung, Lucian Michael Freud, Galina Ulanova, Werner Heisenberg, Alec Guinness and Sebastião Salgado. Astronomer Maria Mitchell was the first woman elected to the Academy, in 1848; the current membership encompasses over 5,700 members based across the United States and around the world.
Academy members include more than 60 Pulitzer Prize winners. The current membership is divided into five classes and twen
Eukaryotes are organisms whose cells have a nucleus enclosed within membranes, unlike prokaryotes, which have no membrane-bound organelles. Eukaryotes belong to Eukarya, their name comes from the Greek εὖ and κάρυον. Eukaryotic cells contain other membrane-bound organelles such as mitochondria and the Golgi apparatus, in addition, some cells of plants and algae contain chloroplasts. Unlike unicellular archaea and bacteria, eukaryotes may be multicellular and include organisms consisting of many cell types forming different kinds of tissue. Animals and plants are the most familiar eukaryotes. Eukaryotes can reproduce both asexually through mitosis and sexually through meiosis and gamete fusion. In mitosis, one cell divides to produce two genetically identical cells. In meiosis, DNA replication is followed by two rounds of cell division to produce four haploid daughter cells; these act as sex cells. Each gamete has just one set of chromosomes, each a unique mix of the corresponding pair of parental chromosomes resulting from genetic recombination during meiosis.
The domain Eukaryota appears to be monophyletic, makes up one of the domains of life in the three-domain system. The two other domains and Archaea, are prokaryotes and have none of the above features. Eukaryotes represent a tiny minority of all living things. However, due to their much larger size, their collective worldwide biomass is estimated to be about equal to that of prokaryotes. Eukaryotes evolved 1.6–2.1 billion years ago, during the Proterozoic eon. The concept of the eukaryote has been attributed to the French biologist Edouard Chatton; the terms prokaryote and eukaryote were more definitively reintroduced by the Canadian microbiologist Roger Stanier and the Dutch-American microbiologist C. B. van Niel in 1962. In his 1937 work Titres et Travaux Scientifiques, Chatton had proposed the two terms, calling the bacteria prokaryotes and organisms with nuclei in their cells eukaryotes; however he mentioned this in only one paragraph, the idea was ignored until Chatton's statement was rediscovered by Stanier and van Niel.
In 1905 and 1910, the Russian biologist Konstantin Mereschkowski argued that plastids were reduced cyanobacteria in a symbiosis with a non-photosynthetic host, itself formed by symbiosis between an amoeba-like host and a bacterium-like cell that formed the nucleus. Plants had thus inherited photosynthesis from cyanobacteria. In 1967, Lynn Margulis provided microbiological evidence for endosymbiosis as the origin of chloroplasts and mitochondria in eukaryotic cells in her paper, On the origin of mitosing cells. In the 1970s, Carl Woese explored microbial phylogenetics, studying variations in 16S ribosomal RNA; this helped to uncover the origin of the eukaryotes and the symbiogenesis of two important eukaryote organelles and chloroplasts. In 1977, Woese and George Fox introduced a "third form of life", which they called the Archaebacteria. In 1979, G. W. Gould and G. J. Dring suggested that the eukaryotic cell's nucleus came from the ability of Gram-positive bacteria to form endospores. In 1987 and papers, Thomas Cavalier-Smith proposed instead that the membranes of the nucleus and endoplasmic reticulum first formed by infolding a prokaryote's plasma membrane.
In the 1990s, several other biologists proposed endosymbiotic origins for the nucleus reviving Mereschkowski's theory. Eukaryotic cells are much larger than those of prokaryotes having a volume of around 10,000 times greater than the prokaryotic cell, they have a variety of internal membrane-bound structures, called organelles, a cytoskeleton composed of microtubules and intermediate filaments, which play an important role in defining the cell's organization and shape. Eukaryotic DNA is divided into several linear bundles called chromosomes, which are separated by a microtubular spindle during nuclear division. Eukaryote cells include a variety of membrane-bound structures, collectively referred to as the endomembrane system. Simple compartments, called vesicles and vacuoles, can form by budding off other membranes. Many cells ingest food and other materials through a process of endocytosis, where the outer membrane invaginates and pinches off to form a vesicle, it is probable that most other membrane-bound organelles are derived from such vesicles.
Alternatively some products produced by the cell can leave in a vesicle through exocytosis. The nucleus is surrounded with pores that allow material to move in and out. Various tube- and sheet-like extensions of the nuclear membrane form the endoplasmic reticulum, involved in protein transport and maturation, it includes the rough endoplasmic reticulum where ribosomes are attached to synthesize proteins, which enter the interior space or lumen. Subsequently, they enter vesicles, which bud off from the smooth endoplasmic reticulum. In most eukaryotes, these protein-carrying vesicles are released and further modified in stacks of flattened vesicles, the Golgi apparatus. Vesicles may be specialized for various purposes. For instance, lysosomes contain digestive enzymes that break down most biomolecules in the cytoplasm. Peroxisomes are used to break down peroxide, otherwise toxic. Many protozoans have contractile vacuoles, which collect and expel excess water, extrusomes, which expel material used to deflect predators or capture prey.
In higher plants, most of a cell's volume is taken up by a central vacuole, whi
Laboratory of Molecular Biology
The Medical Research Council Laboratory of Molecular Biology is a research institute in Cambridge, involved in the revolution in molecular biology which occurred in the 1950–60s. Since it has remained a major medical research laboratory with a much broader focus. A new £212m replacement building constructed close by to the original site on the Cambridge Biomedical Campus was opened in May 2013; the road outside the new building is named Francis Crick Avenue after the 1962 joint Nobel Prize winner, who co-discovered the helical structure of DNA in 1953. The LMB has a deliberately simple administrative environment. From outside the LMB, the parent MRC ensured that the quinquennial assessment had a light touch: only a brief explanation of past achievements and an indication of where future plans lay were required by the external committee, their recommendations were advisory, leaving the division leaders a free hand as to how to run their affairs: they were assumed to know best. Within the LMB, Perutz’s criterion of how to arrange things was that the act of doing science should be facilitated at all levels.
The LMB had a single budget: there were no personal budgets or equipment — everything was communal. It had state of the art equipment and was well financed by the MRC. Chemical reagents and other expendables could be withdrawn from a single store with only a signature required. Key to the smooth functioning of the lab was Michael Fuller, responsible for its day-to-day running. There was no overt hierarchy. Most members of the lab met in the canteen, said to assist inter-divisional communication and collaboration. Today the LMB has around 400 scientists, of whom 130 are 90 students; the new building was opened in 2013 and has four seminar rooms named after LMB scientists: Sydney Brenner, Aaron Klug, the late César Milstein and Frederick Sanger. as well as another lecture theatre named after the late Max Perutz. As of 2018 there are around fifty group leaders Groups are part of one of the four divisions of the LMB: Cell Biology, Neurobiology and Nucleic Acid Chemistry and Structural Studies; as of 2018 group leaders include the following people: The LMB is home to a number of Emeritus Scientists, pursuing their research interests in the Laboratory after their formal retirement including: Max Perutz, following an undergraduate training in organic chemistry, left Austria in 1936 and came to the University of Cambridge to study for a PhD, joining the X-ray crystallographic group led by J.
D. Bernal. Here, in the Cavendish laboratory, he started his lifelong work on hemoglobin; the death of Lord Rutherford led to his successor, Lawrence Bragg, a pioneer in X-ray crystallography, becoming the new Cavendish professor of physics in 1938. Bragg became his group in those early days. After World War II, many scientists from the physical side of science turned to biology, bringing with them a new way of thinking and expertise. John Kendrew joined Perutz’s group to study a protein related to hemoglobin — myoglobin — in 1946. In 1947, the Medical Research Council, under the guidance of its Secretary Harold Himsworth, decided to form and support the “MRC Unit for the Study of the Molecular Structure of Biological Systems”; the group, which by 1948 included Hugh Huxley working on muscle, was joined in 1949 by Francis Crick, who worked on protein crystallography. In 1951 they were joined by James Watson. 1953 was an annus mirabilis: Watson and Crick discovered the double-helical structure of DNA, which revealed that biological information was encoded in a linear structure and how this information could be duplicated during cell division.
Perutz discovered that the detailed three-dimensional structures of proteins, such as myoglobin and hemoglobin could, in principle, be solved by X-ray analysis using a heavy metal atom labeling technique. Hugh Huxley discovered. In 1957 the group’s name was changed to the “MRC Unit for Molecular Biology”; that year, Vernon Ingram discovered that the disease sickle cell anaemia is caused by a single amino acid change in the hemoglobin molecule and Sydney Brenner joined the Unit. In 1958, Crick’s review “On Protein Synthesis” appeared: this laid out, for the first time, the central dogma of molecular biology, the sequence hypothesis and the adaptor hypothesis. In 1961 Brenner helped discover messenger RNA and, in the same year, he and Crick established that the genetic code was read in triplets. All this work was accomplished in a single-storey temporary building, a few rooms in the Austin Wing, a room with a lean-to glass front and a short sealed off corridor within the Cavendish laboratory; the MRC built a new Laboratory on the outskirts of Cambridge — the LMB — into which the Unit from the Cavendish moved in early 1962.
Additionally, Fred Sanger’s Unit, housed in the University’s Biochemistry department joined them, as did Aaron Klug from London. Sanger had invented methods for determining the sequence of amino acids in a protein: he was awarded the Nobel prize for chemistry in 1958 for the first protein sequence, that of insulin; the new laboratory was opened by Queen Elizabeth II in 1962. That year and Perutz shared the Nobel prize for chemistry and Crick and Watson received a share of the Nobel prize for physiology or medicine; the LMB building was incorporated into the new Addenbrooke's Hospital complex as this was constructed in the 1970s. The new LMB had Perutz as its chairman and contained 3 divisions: Structural Studies, headed by Kendrew.
Enzymes are macromolecular biological catalysts. Enzymes accelerate chemical reactions; the molecules upon which enzymes may act are called substrates and the enzyme converts the substrates into different molecules known as products. All metabolic processes in the cell need enzyme catalysis in order to occur at rates fast enough to sustain life. Metabolic pathways depend upon enzymes to catalyze individual steps; the study of enzymes is called enzymology and a new field of pseudoenzyme analysis has grown up, recognising that during evolution, some enzymes have lost the ability to carry out biological catalysis, reflected in their amino acid sequences and unusual'pseudocatalytic' properties. Enzymes are known to catalyze more than 5,000 biochemical reaction types. Most enzymes are proteins; the latter are called ribozymes. Enzymes' specificity comes from their unique three-dimensional structures. Like all catalysts, enzymes increase the reaction rate by lowering its activation energy; some enzymes can make their conversion of substrate to product occur many millions of times faster.
An extreme example is orotidine 5'-phosphate decarboxylase, which allows a reaction that would otherwise take millions of years to occur in milliseconds. Chemically, enzymes are like any catalyst and are not consumed in chemical reactions, nor do they alter the equilibrium of a reaction. Enzymes differ from most other catalysts by being much more specific. Enzyme activity can be affected by other molecules: inhibitors are molecules that decrease enzyme activity, activators are molecules that increase activity. Many therapeutic drugs and poisons are enzyme inhibitors. An enzyme's activity decreases markedly outside its optimal temperature and pH, many enzymes are denatured when exposed to excessive heat, losing their structure and catalytic properties; some enzymes are used commercially, in the synthesis of antibiotics. Some household products use enzymes to speed up chemical reactions: enzymes in biological washing powders break down protein, starch or fat stains on clothes, enzymes in meat tenderizer break down proteins into smaller molecules, making the meat easier to chew.
By the late 17th and early 18th centuries, the digestion of meat by stomach secretions and the conversion of starch to sugars by plant extracts and saliva were known but the mechanisms by which these occurred had not been identified. French chemist Anselme Payen was the first to discover an enzyme, diastase, in 1833. A few decades when studying the fermentation of sugar to alcohol by yeast, Louis Pasteur concluded that this fermentation was caused by a vital force contained within the yeast cells called "ferments", which were thought to function only within living organisms, he wrote that "alcoholic fermentation is an act correlated with the life and organization of the yeast cells, not with the death or putrefaction of the cells."In 1877, German physiologist Wilhelm Kühne first used the term enzyme, which comes from Greek ἔνζυμον, "leavened" or "in yeast", to describe this process. The word enzyme was used to refer to nonliving substances such as pepsin, the word ferment was used to refer to chemical activity produced by living organisms.
Eduard Buchner submitted his first paper on the study of yeast extracts in 1897. In a series of experiments at the University of Berlin, he found that sugar was fermented by yeast extracts when there were no living yeast cells in the mixture, he named the enzyme that brought about the fermentation of sucrose "zymase". In 1907, he received the Nobel Prize in Chemistry for "his discovery of cell-free fermentation". Following Buchner's example, enzymes are named according to the reaction they carry out: the suffix -ase is combined with the name of the substrate or to the type of reaction; the biochemical identity of enzymes was still unknown in the early 1900s. Many scientists observed that enzymatic activity was associated with proteins, but others argued that proteins were carriers for the true enzymes and that proteins per se were incapable of catalysis. In 1926, James B. Sumner crystallized it; the conclusion that pure proteins can be enzymes was definitively demonstrated by John Howard Northrop and Wendell Meredith Stanley, who worked on the digestive enzymes pepsin and chymotrypsin.
These three scientists were awarded the 1946 Nobel Prize in Chemistry. The discovery that enzymes could be crystallized allowed their structures to be solved by x-ray crystallography; this was first done for lysozyme, an enzyme found in tears and egg whites that digests the coating of some bacteria. This high-resolution structure of lysozyme marked the beginning of the field of structural biology and the effort to understand how enzymes work at an atomic level of detail. An enzyme's name is derived from its substrate or the chemical reaction it catalyzes, with the word ending in -ase. Examples are alcohol dehydrogenase and DNA polymerase. Different enzymes that catalyze the same chemical reaction are called isozymes; the International Union of Biochemistry and Molecular Biology have developed a nomenclature for enzymes, the EC numbers. The first number broadly classifies the enzyme based on its mechanism; the top-level classification is: EC 1, Oxidoreductases: catalyze oxidation/reducti
Lomonosov Gold Medal
The Lomonosov Gold Medal, named after Russian scientist and polymath Mikhail Lomonosov, is awarded each year since 1959 for outstanding achievements in the natural sciences and the humanities by the USSR Academy of Sciences and the Russian Academy of Sciences. Since 1967, two medals are awarded annually: one to a foreign scientist, it is the Academy's highest accolade. Pyotr Leonidovich Kapitsa: cumulatively, for works in physics of low temperatures. Aleksandr Nikolaevich Nesmeyanov: accumulatively for works in chemistry. Sin-Itiro Tomonaga: for substantial scientific contributions to the development of physics. Hideki Yukawa: for outstanding merits in the development of theoretical physics. Sir Howard Walter Florey: for an outstanding contribution in the development of medicine. Nikolai Vasilevich Belov: accumulatively for works in crystallography. Igor Yevgenyevich Tamm: for outstanding achievements in the theory of elementary particles and other domain of theoretical physics Cecil Frank Powell: for outstanding achievements in the physics of elementary particles.
Vladimir Aleksandrovich Engelgardt: for outstanding achievements in biochemistry and molecular biology. István Rusznyák: for outstanding achievements in medicine. Nikolay Nikolaevich Semenov: for outstanding achievements in chemical physics. Giulio Natta: for outstanding achievements in the chemistry of polymers Ivan Matveevich Vinogradov: for outstanding studies in mathematics. Arnaud Denjoy: for outstanding achievements in mathematics. Viktor Amazaspovich Ambartsumian: for outstanding achievements in astronomy and astrophysics. Hannes Alfvén: for outstanding achievements in physics of plasma and astrophysics. Nikoloz Muskhelishvili: for outstanding achievements in mathematics and mechanics. Max Steenbeck: for outstanding achievements in the physics of plasma and applied physics. Aleksandr Pavlovich Vinogradov: for outstanding achievements in geochemistry. Vladimír Zoubek: for outstanding achievements in geology. Aleksandr Ivanovich Tselikov: for outstanding achievements in metallurgy and metal technology.
Angel Balevski: for outstanding achievements in metallurgy and metal technology. Mstislav Vsevolodovich Keldysh: for outstanding achievements in mathematics and space research. Maurice Roy: for outstanding achievements in mechanics and its applications. Semyon Isaakovich Volfkovich: for outstanding achievements in chemistry and the technology of phosphorus and the development of scientific foundations of chemicalization of agriculture in the USSR. Herman Klare: for outstanding achievements in the chemistry and technology of man-made fibers. Mikhail Alekseevich Lavrentiev: for outstanding achievements in mathematics and mechanics. Linus Carl Pauling: for outstanding achievements in chemistry and biochemistry. Anatolii Petrovich Aleksandrov: for outstanding achievements in nuclear science and technology. Alexander Robertus Todd: for outstanding achievements in organic chemistry. Aleksandr Ivanovich Oparin: for outstanding achievements in biochemistry. Béla Szőkefalvi-Nagy: for outstanding achievements in mathematics.
Boris Yevgenevich Paton: for outstanding achievements in metallurgy and metal technology. Jaroslav Kožešník: for outstanding achievements in applied mathematics and mechanics. Vladimir Aleksandrovich Kotelnikov: for outstanding achievements in radiophysics, radio engineering and electronics. Pavle Savić: for outstanding achievements in chemistry and physics. Julii Borisovich Khariton: for outstanding achievements in physics. Dorothy Crowfoot Hodgkin: for outstanding achievements in biochemistry and crystal chemistry. Andrei Lvovich Kursanov: for outstanding achievements in physiology and biochemistry of plants. Abdus Salam: for outstanding achievements in physics. Nikolai Nikolaevich Bogolyubov: for outstanding achievements in mathematics and theoretical physics. Rudolf Mössbauer: for outstanding achievements in physics. Mikhail Aleksandrovich Sadovsky: for outstanding achievements in geology and geophysics. Guillermo Haro: for outstanding achievements in astrophysics. Svyatoslav Nikolaevich Fyodorov: for outstanding achievements in ophthalmology and eye microsurgery.
Josef Řiman: for outstanding achievements in biochemistry. Aleksandr Mikhailovich Prokhorov: for outstanding achievements in physics. John Bardeen: for outstanding achievements in physics. Sergei Lvovich Sobolev: for outstanding achievements in mathematics. Jean Leray: for outstanding ach
Escherichia virus T4
Escherichia virus T4 is a species of bacteriophages that infect Escherichia coli bacteria. It is a member of virus subfamily Tevenvirinae and includes among other strains Enterobacteria phage T2, Enterobacteria phage T4 and Enterobacteria phage T6. T4 is capable of undergoing only a lytic lifecycle and not the lysogenic lifecycle; the T4 virus's double-stranded DNA genome encodes 289 proteins. The T4 genome is terminally redundant and is first replicated as a unit several genomic units are recombined end-to-end to form a concatemer; when packaged, the concatemer is cut at unspecific positions of the same length, leading to several genomes that represent circular permutations of the original. The T4 genome bears eukaryote-like intron sequences; the Shine-Dalgarno sequence GAGG dominates in virus T4 early genes, whereas the sequence GGAG is a target for the T4 endonuclease RegB that initiates the early mRNA degradation. T4 is a large virus, at 90 nm wide and 200 nm long; the DNA genome is held in an icosahedral head known as a capsid.
The T4’s tail is hollow so that it can pass its nucleic acid into the cell it is infecting after attachment. The tail attaches to a host cell with the help of tail fibres; the tail fibres are important in recognizing host cell surface receptors, so they determine if a bacterium is within the virus's host range. The structure of the 6 megadalton T4 baseplate that comprises 127 polypeptide chains of 13 different proteins has been described in atomic detail. An atomic model of the proximal region of the tail tube formed by gp54 and the main tube protein gp19 have been created; the tape measure protein gp29 is present in the baseplate-tail tube complexes, but it could not be modeled. The T4 virus initiates an Escherichia coli infection by binding OmpC porin proteins and lipopolysaccharide on the surface of E. coli cells with its long tail fibers. A recognition signal is sent through the LTFs to the baseplate; this unravels the short tail fibers. The baseplate changes conformation and the tail sheath contracts, causing GP5 at the end of the tail tube to puncture the outer membrane of the cell.
The lysozyme domain of GP5 degrades the periplasmic peptidoglycan layer. The remaining part of the membrane is degraded and DNA from the head of the virus can travel through the tail tube and enter the E. coli cell. The lytic lifecycle takes 30 minutes and consists of: Adsorption and penetration Arrest of host gene expression Enzyme synthesis DNA replication Formation of new virus particles After the life cycle is complete, the host cell bursts open and ejects the newly built viruses into the environment, destroying the host cell. T4 has a burst size of 100-150 viral particles per infected host. Complementation and recombination tests can be used to map out the rII gene locus by using T4; these Escherichia viruses infect a host cell with their information and blow up the host cell, thereby propagating themselves. Virus T4 genome is synthesized within the host cell using Rolling Circle Replication; the time it takes for DNA replication in a living cell was measured as the rate of virus T4 DNA elongation in virus-infected E. coli.
During the period of exponential DNA increase at 37 °C, the rate was 749 nucleotides per second. The mutation rate per base pair per replication during virus T4 DNA synthesis is 1.7 per 10−8, a accurate DNA copying mechanism, with only 1 error in 300 copies. The virus codes for unique DNA repair mechanisms; the T4 DNA packaging motor has been found to load DNA into virus capsids at a rate up to 2000 base pairs per second. The power involved, if scaled up in size, would be equivalent to that of an average automobile engine. Multiplicity reactivation is the process by which two or more virus genomes, each containing inactivating genome damage, can interact within an infected cell to form a viable virus genome. Salvador Luria, while studying UV irradiated virus T4 in 1946, discovered MR and proposed that the observed reactivation of damaged virus occurs by a recombination mechanism; this preceded the confirmation of DNA as the genetic material in 1952 in related virus T2 by the Hershey–Chase experiment.
As remembered by Luria the discovery of reactivation of irradiated virus started a flurry of activity in the study of repair of radiation damage within the early phage group. It turned out that the repair of damaged virus by mutual help that Luria had discovered was only one special case of DNA repair. Cells of all types, not just and their viruses, but all organisms studied, including humans, are now known to have complex biochemical processes for repairing DNA damages. DNA repair processes are now recognized as playing critical roles in protecting against aging and infertility. MR is represented by "survival curves" where survival of plaque forming ability of multiply infected cells is plotted against dose of genome damaging agent. For comparison, the survival of virus plaque forming ability of singly infected cells is plotted against dose of genome damaging agent; the top figure shows the survival curves for v