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1861-1881
1882-1891
1892-1902
1903-1917
1918-1932
1932-1942
1943-1955
1956-1965
1966-1976
1977-1986
1988-present

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What you should know...

Milestones in Microbiology

Microbiology: A Centenary Perspective

Significant Events Of The Last 125 Years

1861 Pasteur introduced the terms aerobic and anaerobic in describing the growth of yeast at the expense of sugar in the presence or absence of oxygen. He observed that more alcohol was produced in the absence of oxygen when sugar is fermented, which is now termed the Pasteur effect. Pasteur, L. "Animalcules infusoires vivant sans gaz oxygene libre et determinant des fermentations." Compt. Rend. Acad. Sci. (Paris) 52:344-347, 1861

1870 Thomas H. Huxley's Biogenesis and Abiogenesis address is the first clear statement of the basic outlines of modern Darwinian science on the question of the origin of life. The terms "biogenesis" (for life only from pre-existing life) and "abiogenesis" (for life from nonliving materials, what had previously been called spontaneous generation) as used by Huxley in this speech have become the standard terms for discussing the subject of how life originates. The speech offered powerful support for Pasteur's claim to have experimentally disproved spontaneous generation. The speech was also Huxley's attempt to define an orthodox Darwinian position on the question, and attempt to define as "non-Darwinian" all those Darwin supporters who believed that spontaneous generation up to the present day was an essential requirement of evolutionary science. Henry Charlton Bastian was the most prominent leader of that faction of Darwinians, though Huxley was so successful in defining them out of the story that very few people today even realize that there WERE Darwinians who were serious, talented evolutionary scientists, yet also thought abiogenesis was necessary in evolution up to the present day. Biogenesis and Abiogenesis James Strick. 1999. Darwinism and the Origin of Life: the Role of H.C. Bastian in the British Spontaneous Generation Debates, 1868-1873. Journal of the History of Biology, 32:1-42 [PDF]

1872 Ferdinand J. Cohn contributes to the founding of the science of bacteriology. In the publication Ueber Bakterien, he discusses the role of microorganisms in the cycling of elements in nature. In 1875, Cohn will publish an early classification of bacteria, using the genus name, Bacillus, for the first time. Cohn, F. 1872. Ueber Bakterien, die kleinsten lebenden Wesen. Lüedritz’sche Verlagsbuchhandlung Carl Habel, Berlin. Cohn, F., 1875. Untersuchungen ueber Bakterien. Beitraege zur Biologie der Planzen 1:127-222 In Milestones in Microbiology: 1556 to 1940, translated and edited by Thomas D. Brock, ASM Press. 1998, p210 [PDF] Ferdinand Cohn, a Founder of Modern Microbiology,  ASM News 65. 1999.p.547 The German botanist Brefeld reported growing fungal colonies from single spores on gelatin surfaces. Prior to this innovation that resulted in the isolation of pure culture of microorganisms, pigmented bacterial colonies were isolated by the German biologist Schroeter on slices of potato incubated in a moist environment. Brefeld, O. Botanische Untersuchungen uber Schimmelpilze, Heft I, Mucor mucedo, Chaetocladium Jones ii, Piptocephalis Fresiana: Zygomyceten, Leipzig, 1872. Schroeter, J. "Ueber einige durch Bacterien gebildete Pigmente." Beitr. Z. Biol. D. Pflanzen 1:2, 109-126.

1876 Robert Koch publishes a paper on his work with anthrax, pointing explicitly to a bacterium as the cause of this disease. This validates the germ theory of disease. Prior, in 1872, he was approved as a district medical officer in Poland where he discovered anthrax was endemic. His work on anthrax was presented and his papers on the subject were published under the auspices of Ferdinand Cohn. Koch, R. 1876. Untersuchungen ueber Bakterien V. Die Aetiologie der Milzbrand-Krankheit, begruendent auf die Entwicklungsgeschichte des Bacillus Anthracis. Beitr. z. Biol. D. Pflanzen 2: 277-310. In Milestones in Microbiology: 1556 to 1940, translated and edited by Thomas D. Brock, ASM Press. 1998, p89 [PDF].

1877 Jean Jacques Theophile Schloesing proves that nitrification is a biological process in the soil by using chloroform vapors to inhibit the production of nitrate. One of the greatest practical applications of this knowledge was in the treatment of sewerage. Schloesing, J. and A. Muntz. 1877. Sur la Nitrification par les Ferments Organises. Comptes Rendus de l’Academie des Sciences, Paris, LXXXIV: 301-303. Robert Koch dries films of bacteria, stains them with methylene blue and then photographs them. He uses cover slips to prepare permanent visual records. Koch, R. 1877. Verfahren zur Untersuchung, zum Conservieren und Photogaphiren der Bakterien. Beitraege zur Biologie der Pflanzen. 2: 399-434 John Tyndall publishes his method for fractional sterilization and clarifies the role of heat resistant factors (spores) in putrefaction. Tyndall’s conclusion adds a final footnote to the work of Pasteur and others in proving that spontaneous generation is impossible. New Details Add to Our Understanding of Spontaneous Generation Controversies, ASM News 63, 1997. p.193 [PDF] Tyndall, J. 1877. On Heat as a Germicide when Discontinuously Applied," Proceedings of the Royal Society of London. 25:569

1878 Thomas Burrill demonstrates for the first time a bacterial disease of plants; Micrococcus amylophorous causes pear blight. Bacteria as the Cause of Disease in Plants: A Historical Perspective, ASM News 45, 1979. p.1  [PDF] Burrill, Thomas Jonathan. 1878. Pear blight. Trans. Ill. State Hort. Soc., 114-116. Joseph Lister publishes his study of lactic fermentation of milk, demonstrating the specific cause of milk souring. His research is conducted using the first method developed for isolating a pure culture of a bacterium, which he names Bacterium lactis. Lister, J. 1878. On lactic fermentation and its bearing on pathology. Trans Path. Soc., Lond. xxix: 425-67. In Milestones in Microbiology: 1556 to 1940, translated and edited by Thomas D. Brock, ASM Press. 1998, p58 [PDF] Serious attention to the trypanosomes of mammals was drawn by the work of Timothy Lewis on the parasite of Indian rats (Trypanosoma lewisi), the importance of which was realized after George Evans (1880) discovered the pathogenic trypanosome in horses and camels in India (Trypanosoma evansi) Lewis, T.R. (1878) "The microscopic organisms found in the blood of man and animals and their relation to disease." Ann. Rpt. San. Commis. Govt. India, Calcutta 14:157 Lewis, T.R. (1879) "Flagellated organisms in the blood of healthy rats." Quart. J. Micr. Sci. 19:109 Evans, G. "Report on the ‘surra’ disease in the Dera Ismail Khan District." Punjab Govt. Milit. Dept. No. 493:446

1879 Albert Neisser identifies Neisseria gonorrhoeoe, the pathogen that causes gonorrhea. He may be the first to attribute a chronic disease to a microbe. Neisser, A. 1879. Ueber eine der Gonorrhoe eigenthumliche Micrococcusform. Vorlaufige Mitteilung. Cbl. F. d. Med. Wiss. 28: 497-500.

1880 Louis Pasteur develops a method of attenuating a virulent pathogen, the agent of chicken cholera, so it would immunize and not cause disease. This is the conceptual break-though for establishing protection against disease by the inoculation of a weakened strain of the causative agent. Pasteur uses the word "attenuated" to mean weakened. As Pasteur acknowledged, the concept came from Jenner’s success at smallpox vaccination. Plasmids, Pasteur, and Anthrax, ASM News 49,1983. p.320 [PDF] Pasteur, L. 1880. Sur les maladies virulentes et en particulier sur la maladie appelee vulgairement cholera des poules. Compt. Rend. Acad. Sc. 90: 239-248. Pasteur, L. 1880. De l’attenuation du virus cholera des poules. Compte rend. Acad. se. 91: 673-680 In Milestones in Microbiology: 1556 to 1940, translated and edited by Thomas D. Brock, ASM Press. 1998, p126 [PDF] C. L. Alphonse Laveran finds malarial parasites in erythrocytes of infected individuals and shows that the parasite enters the organism and replicates. Laveran was awarded the Noble Prize in Medicine and Physiology in 1907 1907 Nobel Prize Laveran, A. 1880. A new parasite found in the blood of malarial patients. Parasitic origin of malarial attacks. Bull. mem. soc. med. hosp. Paris. 17: 158-164.

1881 Robert Koch struggles with the disadvantages of using liquid media for certain experiments. He seeks out alternatives, and first uses an aseptically cut slice of a potato as a solid culture medium. He also turns to gelatin, which is added to culture media; the resulting mixture is poured onto flat glass plates and allowed to gel. The plate technique is used to isolate pure cultures of bacteria from colonies growing on the surface of the plate. Koch publishes his Methods for the Study of Pathogenic Organisms in which he describes his success with solidified culture media. Koch, R. 1881. Zur Untersuchung von pathogenen Organismen. Mitth. a. d. Kaiserl. Gesundheitsampte 1: 1-48. In Milestones in Microbiology: 1556 to 1940, translated and edited by Thomas D. Brock, ASM Press. 1998, p101 [PDF] Paul Ehrlich refines the use of the dye methylene blue in bacteriological staining and uses it to stain the tubercule bacillus. He shows the dye binds to the bacterium and resists decoloration with an acid alcohol wash.. Ehrlich, P. 1881 Ueber das Methylenblau und seine klinisch-bakterioskopische Verwerthung. Ztschr. f. klin. Med. ii: 710-713. Ehrlich, P. 1882. Aus dem Verein fur innere Medicin zu Berlin. Deutsche medizinische Wochenschrift 8:269-270 In Milestones in Microbiology: 1556 to 1940, translated and edited by Thomas D. Brock, ASM Press. 1998, p118 [PDF] Koch systematically investigated the efficacy of chemical disinfectants demonstrating that carbolic acid used by Lister in aseptic surgery was merely bacteriostatic and not bactericidal. He first recognized that disinfection depended on the chemical concentration and contact time. Anthrax spores were dried on silk threads, exposed to disinfectants, washed with sterile water and cultured to evaluate a range of chemicals. Koch, R. "Ueber Desinfection." Mittheilungen aus dem kaiserlichen Gesundheitsamt 1:234-282, 1881

1882 Angelina Fannie and Walther Hesse in Koch?s laboratory use agar, an extract of algae, as a solidifying agent to prepare solid media for growing microbes. Fannie suggests the use of agar-agar after leanring of it from friends who cook. Agar replaces gelatin because it remains solid at temperatures up to 100 degrees centigrade, it is clear, and it resists digestion by bacterial enzymes. Walther and Angelina Hesse: Early Contributors to Bacteriology, ASM News 58, 1992. p.425 [PDF] No formal article was published but see: Hitchins, Arthur Parker and Morris C. Leikind, 1939. The Introduction of Agar-Agar Into Bacteriology. Journal of Bacteriology. 37: 485-493. Robert Koch also mentions the cultivation of bacteria in agar-agar in The Aetiology of Tuberculosis. See below. Robert Koch isolates the tubercule bacillus, Mycobacterium tuberculosis. The search for the tubercule bacillus is more difficult that anthrax. He finally isolates the bacillus from the tissues of a workman and stains them with methylene blue, yielding blue colored rods with bends and curves. He injects the tissues from people who had died into animals and then grows the bacilli he isolates into pure cultures. Koch, R. 1882. Die Aetiologie der Tuberculose. Berl. Klin. Wchnschr., xix: 221-230. In Milestones in Microbiology: 1556 to 1940, translated and edited by Thomas D. Brock, ASM Press. 1998, p109 [PDF]

1883 Edward Theodore Klebs and Fredrich Loeffler independently discover Corynebacterium diphtheriae, which causes diphtheria. Loeffler later shows that the bacterium secretes a soluble substance that affects organs beyond sites where there is physical evidence of the organism. Klebs, E. 1883. Ueber Diphtherie. Verh. D. Congresses f. Inn. Med., II. Congr.Bergmann Weisbaden. 139-154. Loeffler, F. 1884. Utersuchung uber die Bedeutung der Mikroorganismen fir die Entstehung der Diptherie beim Menschen, bei der taube und beim Kalbe. Mitth. a. d. kaiserl. Gesundheitsampte. Ii: 421-499. Ulysse Gayon and Gabriel Dupetit isolate in pure culture two strains of denitrifying bacteria. They show that individual organic compounds, such as sugars and alcohols, can replace complex organics and serve as reductants for nitrate, as well as serving as carbon sources. 1986: Centenary of the Isolation of Denitrifying Bacteria, ASM News 52, 1986. p.627 [PDF] Gayon, U., and G. Dupetit. 1883. La fermentation des nitrates. Mem. Soc. Sci. Phys. Nat. Bordeaux Ser. 2. 5: 35-36.

1884 Ilya Ilich Metchnikoff demonstrates that certain body cells move to damaged areas of the body where they consume bacteria and other foreign particles. He calls the process phagocytosis. He proposes a theory of cellular immunity. With Ehrlich, Metchnikoff is awarded the Noble Prize in Medicine and Physiology in 1908 1908 Nobel Prize Centennial of the Rise of Cellular Immunology: Discovery at Messina, ASM News 48, 1982. p.558 [PDF] Metschnikoff, E. 1884. Ueber eine Sprosspilzkrankheit der Daphnien. Beitrag zur Lehre uber den Kampf der Phagocyten gegen Krankheitserrenger, Archiv f. pathologische Anatomie und Physiologie und f. klinische Medicin, 96: 177-195. In Milestones in Microbiology: 1556 to 1940, translated and edited by Thomas D. Brock, ASM Press. 1998, p132 [PDF] Robert Koch puts forth what will become his best-known work, a set of postulates, or standards of proof involving the tubercle bacillus. Koch's postulates are published in a work titled the The Etiology of Tuberculosis. The paper includes a demonstration of three major facts: 1) the presence of the tubercule bacillus (as proved by staining) in tubercular lesions of various organs of humans and animals, 2) the cultivation of the organisms in pure culture on blood serum, and 3) the production of tuberculosis at will by its inoculation into guinea pigs. Koch was awarded the Nobel Prize in Medicine and Physiology in 1905 1905 Nobel Prize The Etiology of Tuberculosis: A Tribute to Robert Koch on the Occasion of the Centenary of His Discovery of the Tubercule Bacillus, ASM News 48, 1982. p.248 [PDF] Preface to Brock's Robert Koch: A Life in Medicine and Bacteriology by James Strick [PDF] Koch, Robert. 1884. Die Aetiologie der Tuberkulose, Mittheilungen aus dem Laiserlichen Gesundheitsampte. 2: 1-88. In Milestones in Microbiology: 1556 to 1940, translated and edited by Thomas D. Brock, ASM Press. 1998, p116 [PDF] Hans Christian J. Gram develops a dye system for identifying bacteria [the Gram stain]. Bacteria which retain the violet dye are classified as gram-positive. The distinction in staining is later correlated with other biochemical and morphological differences. Gram, C. 1884. Ueber die isolirte Farbung der Schizomyceten in Schitt-und Trockenpreparaten, Fortschritte der Medicin, 2: 185-189. In Milestones in Microbiology: 1556 to 1940, translated and edited by Thomas D. Brock, ASM Press. 1998, p215 [PDF] Together with Pasteur, the French firm Chamberland’s Autoclave, develops a chamber to sterilize materials using superheated steam. Chamberland, C. 1884. Sur un filtre donnant de l’eau physiologiquement pure. Compt. Rend. Acad. d. sc. Paris. xcix: 247.

1885 As part of his rabies research, Louis Pasteur oversees injections of the child Joseph Meister with "aged" spinal cord allegedly infected with rabies virus. Pasteur uses the term "virus" meaning poison, but has no idea of the nature of the causitive organism. Although the treatment is successful, the experiment itself is an ethical violation of research standards. Pasteur knew he was giving the child successively more dangerous portions. Pasteur: High Priest of Microbiology, ASM News 61, 1995. p.575 [PDF] Pasteur’s Dilemma: The Road Not Taken. ASM News vol. 40, 1974, p. 703 [PDF] Preface to René Dubos' Pasteur and Modern Science by Gerald L. Geison [PDF] Pasteur, L. 1885. Methode pour prevenir la rage apres morsure, Compt rend. Acd. Sc. 101: 765-773. Paul Ehrlich espouses the theory that certain chemicals, such as dyes, affect bacterial cells and reasoned that these chemicals could be toxic against microbes, work that lays the foundation for his development of arsenic as a treatment for syphilis. Ehrlich, P. 1885. Das Sauerstoff-Bedurfniss des Organismus, eine farbanalytische Studie. Hirschwald, Berlin. Theodor Escherich identifies a bacterium, that is a natural inhabitant of the human gut, which he names Bacterium coli. He shows that certain strains are responsible for infant diarrhea and gastroenteritis. Escherich, T. 1885. Die Darmbakterien des Neugeborenen und Sauglings, Fortschr.d. Med. 3: 515-522; 251-251,

1886 Theobald Smith and D. E. Salmon inject heated killed whole cell vaccine of hog cholera into pigeons and demonstrate immunity to subsequent administration of a live microbial culture. The organism is a bacterium and unrelated to hog cholera or swine plague disease, which is caused by a virus. Salmon, D. E. and T. Smith. On a new method of producing immunity from contagious diseases, Proceedings of the Biological Society, (Washington, D. C.) 3: 29-33.

1887 Sergei Winogradsky studies Beggiatoa and determines that it can use inorganic H2S as an energy source and CO2 as a carbon source. He establishes the concept of autotrophy and its relationship to natural cycles. Winogradsky, S. 1887. Uber Schwefelbacterien. Botanische Zeitung. XLV: 489-507. Julius Richard Petri working in Koch’s laboratory, introduces a new type of culture dish for semi-solid media. The dish has an overhanging lid that keeps contaminants out. Petri, R. J. 1887. Eine kleine Modification des Koch’schen Plattenverfahrens. Centralbl. F. Bakteriol., etc., 1: 279-280 In Milestones in Microbiology: 1556 to 1940, translated and edited by Thomas D. Brock, ASM Press. 1998, p218 [PDF]

1888 The Institut Pasteur is founded in France in November. Emile Roux and Alexandre Yersin show that Cornyebacterium diphtheriae affects tissues and organs by a toxin. They use a filtrate from cells that can directly kill laboratory animals. From "Diphtheritic" Poison to Molecular Toxinology, ASM News 53, 1987. p.547 [PDF] Roux E. and A. Yersin. 1888. Contribution a l’etude de la diphtherie. Ann. Inst. Pasteur 2: 629-661. 3: 273. Martinus Beijerinck uses enrichment culture, minus nitrogenous compounds, to obtain a pure culture of the root nodule bacterium Rhizobium, demonstrating that enrichment culture creates the conditions for optimal growth of a desired bacterium. Early Biotechnology: The Delft Connection, ASM News 59, 1993. p.401 [PDF] Beijerinck, M. 1888. Die Bakterien de Papilionaceenknollchen. Botanische Zeitung, Vol. 46: 725-804. In Milestones in Microbiology: 1556 to 1940, translated and edited by Thomas D. Brock, ASM Press. 1998, p220 [PDF] Hellriegel and Wilfarth describe symbiotic nitrogen fixation by nodulated legumes. Hellriegel first reported this to a scientific meeting in September 1886, and published a somewhat more extensive paper a few weeks later. The 1888 publication with Wilfarth is considered to be "the classical paper." Hellriegel, H, and Wilfarth, H. "Untersuchungen uber die Stickstoffnahrung der Gramineen und Leguminosen." Beilageheft zu der Zeitschrift des Vereins fur Rubenzucker-Industrie Deutschen Reichs, 234 pp., 1888

1889 A. Charrin and J. Roger discover that bacteria can be agglutinated by serum. Charrin, A. and J. Roger. 1889. Note sur le developpement des microbes pathogens dans le serum des animaux vaccines. Soc. De Biol. 9e ser., I: 667-669. Kitasato obtained the first pure culture of the strict anaerobic pathogen, the tetanus bacillus Clostridium tetani. Taking advantage of the fact that the spores of the organism are extremely heat-resistant, he heated a mixed culture of C. tetani and other bacteria at 80 degrees for one hour, then cultivated them in a hydrogen atmosphere. Kitasato, S. "Ueber den Tetanusbacillus." Ztschr. Hyg. u. Infektionskrank. 7:225-234, 1889

1890 Emil von Behring and Shibasaburo Kitasato working together in Berlin in 1890 announce the discovery of diphtheria antitoxin serum, the first rational approach to therapy of infectious diseases. They inject a sublethal dose of diphtheria filtrate into animals and produce a serum that is specifically capable of neutralizing the toxin. They then inject the antitoxin serum into an uninfected animal to prevent a subsequent infection. Behring, trained as a surgeon, was a researcher for Koch. Kitasato was Koch’s first student at the Institute of Hygiene. Behring was awarded the Nobel Prize in Medicine and Physiology in 1901 1901 Nobel Prize Behring, E. 1890. Untersuchungen ueber das Zustandekommen der Diphtherie-Immunitat bei Thieren. Dt. Med. Wochenschr. 16: 1145-1148. In Milestones in Microbiology: 1556 to 1940, translated and edited by Thomas D. Brock, ASM Press. 1998, p141 [PDF] Behring, E. and Kitasato, S. 1890. Ueber das Zustandekommen der Diphtherie-Immunitat und der Tetanus-Immunitat bei thieren. Deutsche medizinsche Wochenschrift 16:1113-1114 In Milestones in Microbiology: 1556 to 1940, translated and edited by Thomas D. Brock, ASM Press. 1998, p138 [PDF] Sergei Winogradsky succeeds in isolating nitrifying bacteria from soil. During the period 1890-1891, Winogradsky performs the major definitive work on the organisms responsible for the process of nitrification in nature. Winogradsky, S. 1890. Recherches sur les Organismes de la Nitrification. Computer Rendu Vol 110: 1013-1016 In Milestones in Microbiology: 1556 to 1940, translated and edited by Thomas D. Brock, ASM Press. 1998, p231 [PDF]

1891 Paul Ehrlich proposes that antibodies are responsible for immunity. He shows that antibodies form against the plant toxins ricin and abrin. With Metchnikoff, Ehrlich is jointly awarded the Nobel Prize in Medicine and Physiology in 1908 1908 Nobel Prize Ehrlich, P. 1891. Experimentelle Untersuchungen uber Immunitat, I. Ueber Ricin, II. Ueber Abrin. Deutsche med. Wchnschr. xvii. 976, 1218.

1892 Dmitri Ivanowski publishes the first evidence of the filterability of a pathogenic agent, the virus of tobacco mosaic disease, launching the field of virology. He passes the agent through candle filters that retain bacteria but isn't sure that he has identified a new region.. When Did Virology Start, ASM News 62, 1996. p.142 [PDF] Tobacco Mosaic Virus and Its Contributions to Virology, ASM News 65, 1999.p.675 Ivanowski, D. I. 1892. On two diseases of tobacco. Sel’. Khoz. Lesov. 169:108-121; an English translation appears as an appendix to Hughes, S. S. (1972). The origins and development of the concept of the virus in the late nineteenth century. Ph.D. thesis, London University. (13; 25; 115) William Welch and George Nuttall identify Clostridium perfringens, the organism responsible for causing gangrene. Welch W. H. and G. Nuttall. 1892. A gas-producing bacillus (b. aerogenes capsulatus, nov.spec.) , capable of rapid development in the blood vessels after death. Johns Hopkins Hosp. Bull. 3: 81-91.

1893 Theobald Smith and F.L. Kilbourne establish that ticks carry Babesia microti, which causes babesiosis in animals and humans. This is the first account of a zoonotic disease and also the foundation of all later work on the animal host and the arthropod vector. Smith, T. and F. L. Kilbourne. 1893. Investigations into the nature, causation and prevention of Texas or southern cattle fever. Bur. Anim. Ind. Bull. 1: 151-152.

1894 Richard Pfeiffer observes that a heat stable toxic material bound to the membrane of Vibrio Cholerae is released only after the cells are disintegrated. He calls the material endotoxin, to distinguish it from filterable material released by bacteria. Pfeiffer, R. 1894. Weitere Untersuchungen ueber das Wesen der Choleraimmunitat und ueber specifisch baktericide Processe. Ztschr. f. Hyg. u. Infektionskrankh. xviii: 1-16. Alexandre Yersin isolates Yersinia (Pasteurella) pestis, the organism that is responsible for bubonic plague. Shibasaburo Kitasato also observes the bacterium in cases of plague Yersin, A. 1894. La peste bubonique a Hong Kong. C. r. Acad. Sci. 119: 356. Yersin, A. 1894. La peste bubonique a Hong Kong. Ann. Inst. Pasteur. 8: 662-667. Kitasato, S. 1894. The bacillus of bubonic plague. Lancet 2: 428-430. Kitasato, S. 1894. Preliminary notice of the bacillus of bubonic plague. Practitioner 53: 311. Kitasato, S. 1894. Preliminary notice of the bacillus of bubonic plague. U. S. Marine Hosp. Serv. P. 343. Martinus Beijerinck isolates the first sulfate-reducing bacterium, Spirillum desulfuricans (Desulfovibrio desulfuricans). Beijerinck, M. 1894. Noty uber dur nacheveis vom protozoen und spirillum in trinkwasser. Centralbl. f. Bakteriol. 15: 10-15

1895 Sergei Winogradsky isolates the first free-living nitrogen-fixing organism, Clostridum pasteurianum. Winogradsky, S. 1895. Recherches sur l’assimilation de l’azote libre de l’atmosphere par les microbes. Arch. d. Sci. Biol., Institut Imperial de Medicine Experimentale, St. Petersburg, Vol. 4. David Bruce describes in great detail the Tsetse fly disease (Nagana - means loss of spirits, depression, in Zulu) in Zululand. He also describes the parasite (drawings of tryp and of tsetse) and demonstrates transmission by infected blood or fly bite. Bruce, D. "Preliminary Report on the Tsetse-Fly Disease, or Nagana, in Zululand." Durban: Bennett & David 1895.

1896 Max Gruber and Herbert Durham extend the 1889 observation of Charrin and Roger to show the agglutination of bacteria by serum is specific. This was recognized as a new disease diagnostic tool. Gruber, M. and H. E. Durham. 1896. Eine neue Methode zur raschen Erkennung des Choleravibrio und des Typhusbacillus. Munchen. Med. Wchnschr. xliii: 285-286.

1897 Paul Ehrlich proposes his "side-chain" theory of immunity and develops standards for toxin and antitoxin. Ehrlich, P. 1897. Zur Kenntniss der Antitoxinwirkung. Fortschr. d. Med. xv: 41. Edward Buchner helps launch the field of enzymology by publishing the first evidence of a cell-free fermentation process using extracts isolated from yeast. This discovery refutes Pasteur’s claim that fermentation requires the repsence of live cells. Buchner is awarded the Nobel Prize in Chemistry in 1907 1907 Nobel Prize Buchner, E. 1897. Alkoholische Gahrung ohne Hefezellen. Berichte der Deutschen Chemischen Gesellschaft, 30: 117-124. In Milestones in Microbiology: 1556 to 1940, translated and edited by Thomas D. Brock, ASM Press. 1998, p65 [PDF] Waldemar Haffkine produces immunity against the plague with killed organisms. Waldemar Haffkine: Pioneer of Cholera Vaccine, ASM News 53, 1987. p.366 [PDF] Haffkine, W. 1897. Remarks on the plague prophylactic fluid. Brit. Med. J. 1: 461. Almwroth Wright and David Sample develop an effective vaccine with killed cells of Salmonella typhi to prevent typhoid fever. Wright, A. E. and D. Sample. 1897. Remarks on vaccination against typhoid fever. British Medical Journal. I: 256-259.

1898 Friedrich Loeffler and Paul Frosch prove that foot-and-mouth disease in livestock is caused by organisms tiny enough to pass through bacteriological filters and too small to be seen through a light microscope. Friedrich Loeffler and His History of Bacteriology, ASM News 48 1982, p.297 [PDF] Loeffler, F. and P. Frosch. 1898. Berichte der Kommission zur Erforschung der Maul-und Klauenseuche bei dem Institut fur Infektionskrankheiten. Part I, 23: 371-391.In Milestones in Microbiology: 1556 to 1940, translated and edited by Thomas D. Brock, ASM Press. 1998, p149  [PDF] Jules Bordet discovers that hemolytic sera acts on foreign blood in a manner similar to the action of antimicrobic sera on microbes by precipitating the material from solution. He shows there are two factors, a heat-labile substance found in normal blood and a bacteriocidal material present in the blood of immunized animals.Bordet is awarded the Nobel Prize in medicine and Physiology in 1919 1919 Nobel Prize Bordet, J. 1898. Sur l’agglutination et la dissolution des globules rouges par le serum d’animaux injectes de sang defibrine. Ann. De l’Inst. Pasteur. xii: 688-695. B. R. Schenck presents the first unequivocal case of sporotrichosis and includes a description of the organism that was first isolated from the patient. This organism was later named Sporotrichum schenckii. Schenk, B. R. 1898. On refractory subcutaneous abscesses caused by a fungus possibly related to the sporotricha. Johns Hopkins Hosp. Bull. 9: 286-290.

1899 Ronald Ross shows that the malarial parasite undergoes a cycle of development in mosquitoes and that the disease is transmitted by the bite of female mosquitoes. Ross was awarded the Noble Prize in Medicine and Physiology in 1902 1902 Nobel Prize Ross, R. 1899. Mosquitoes and malaria. Brit. Med. J., 432-433. Martinus Beijerinck recognizes "soluble" living microbes, a term he applies to the discovery of tobacco mosaic virus. A filtrate free of bacteria retains ability to cause disease in plants even after repeated dilutions.In 1897 he had pressed the juice from tobacco leaves infected with tobacco mosaic disease, which gave the leaves a mottled appearance. Martinus Beijerinck (1851-1931), ASM News 62, 1996. p.539 [PDF] Beijerinck, M. 1899. Ueber ein Contagium vivum fluidum als Ursache der Fleckenkrankheit der Tabaksblatter. Centralblatt fur bacteriologie und Parasirenkunde, Part II, 5: 27-33. In Milestones in Microbiology: 1556 to 1940, translated and edited by Thomas D. Brock, ASM Press. 1998, p153 [PDF] The organizing meeting of the Society of American Bacteriologists is held at Yale, December 28, 1899. The Society is the first independent organization devoted to the promotion and service of bacteriology in the United States. It later becomes the American Society for Microbiology. There was no formal published paper but see: Conn, H.J. 1948. Professor Herbert William Conn and the founding of the American Society of American Bacteriologists. Bact. Reviews. 12: 275-296. Abstracts of the first meeting were published in SCIENCE N.S. Vol. XI, No. 273: 455-463, 1900 A Century of Society Meetings, ASM News 65, 1999. p.296 Society Founded by "Lost Souls" Among Naturalists, ASM News, 65 1999.p.266

1900 Based on work of Walter Reed, it is demonstrated that Yellow Fever is caused by a filterable virus transmitted by mosquitoes. The agent is similar to that reported in 1898 by Loffler and Frosch for foot and mouth disease of cattle. This is the first report of a viral agent known to cause human disease. Based on the findings of the Yellow Fever Commission the mosquito was eradicated. No account was published immediately, but the papers of the Yellow Fever Commission were published in 1911. Reed, W. 1911. Papers by various authors of the Yellow Fever Commission. Sen. Doc. 822. Washington, D. C. W. Ophuls and H. C. Moffitt correctly identify the etiologic agent of coccidioidomycosis, Coccidiodes immitis, as a mold. This was formerly described as a protozoan. Ophuls, W. and H. Moffitt. 1900. A new pathogenic mould. Philadelphia Med. J. 5: 1471-1472.

1901 Jules Bordet and Octave Gengou develop the complement fixation test. They show that any antigen-antibody reaction leads to the binding of complement to the target antigen. Bordet, J. and O. Gengou. 1901. Sur l’existencede substances sensibilisatrices dans la plupart des serums antimicrobiens. Ann. De l’Inst. Pasteur. xv: 289-303. E. Wildiers publishes the first description of a microbial growth factor, opening the field of vitamin research. He finds that a water soluble extract of yeast has a compund that is required for the growth of yeast. The material is later found to be a B vitamin. Wildiers, E. 1901. A new substance indispensable to the development of yeast. La Cellule. 18: 313-332. In Milestones in Microbiology: 1556 to 1940, translated and edited by Thomas D. Brock, ASM Press. 1998, p240 [PDF]

1903 William Leishman observes Leishmania donovani in the spleen of a soldier who dies from Dum-Dum fever. Charles Donovan helps to identify the protozoan causing the disease. Leishman, W. B. 1903. On the possibility of the occurrence of trypanosomiasis in India. Br. Med. J. i: 1252-1254. Donovan, C. 1903. On the possibility of the occurrence of trypanosomiasis in India. Br. Med. J. ii: 79. F. G. Novy cultivates trypanosomes isolated in the blood of rats. Novy, F. G. and W. J. MacNeal. 1903. On the cultivation of Trypanosoma lewisi. Contributions to Medical Research, Ann Arbor: George Wahr. 549-577.

1904 Martinus Beijerinck obtains the first pure culture of sulfur-oxidizing bacterium, Thiobacillus denitrificans. Under anaerobic conditions it uses carbon dioxide as a source of carbon. Beijerinck, M. 1904. Phenomenes de reduction produits par les microbes. Arch. Neerl. (section 2) 9: 131-157. Cornelius Johan Koning suggests that fungi play an important role in the decomposition of organic matter and the formation of humus. Koning, C. J. 1904. Beitrage zur kenntnis des lebens dur humuspilze und der chemischen vorgange bei der humusbildung. Arch. Neerland. Sci. Exact. Et Nat. 9:34-107.

1905 Franz Schardinger isolates aerobic bacilli which produce acetone, ethanol, and acetic acid. These are important industrial chemicals. Schardinger, F. 1904. Bacillus macerans. Centralblatt f. Backteriologie, II XIV: 772. Fritz R. Schaudinn and Erich Hoffman identify Treponema pallidum, the cause of syphilis. The bacterium is isolated from fluid leaking from a syphylitic chancre and is spiral in appearance. Metchnikoff and Syphilis Research during a Decade of Discovery, ASM News 62, 1966. p.307 [PDF] Schaudinn, F. R. and E. Hoffman. 1905. Uber Spirochatenbefunde in Lymphdrusensaft Syphilitischer. Dtsch. med. Wschr. 31: 711. Shigetane Ishiwata discovers that the cause of a disease outbreak in silkworms is a new species of bacteria, later called Bacillus thuringiensis, or Bt. Ishiwata called the organism "Sotto-Bacillen." ("Sotto" in Japanese signifies sudden collapse.) Ishiwata, S. 1905. Concerning "Sotto-Kin" a bacillus of a disease of the silkworm. Rept. Assoc. Seric. Japan. Pp. 160-161. Sir Roland Biffen shows that the ability of wheat to resist infection with a fungus is genetically inherited. Biffen, R.H. 1905 Experiments with wheat and barley hybrids, illustrating Mendel’s Laws of heredity. J. Roy. Agric. Soc. 65:337-45

1906 August von Wasserman describes the "Wasserman reaction" for the diagnosis of syphilis in monkeys. The test uses complement fixation and becomes the basis for the general uses of complement tests as diagnostics. Wasserman, A., Neisser, A., and C. Bruck. 1906. Eine serodiagnostische reaktion bei syphilis. Deutsche med. Wchnschr xxxii: 745. N. L. Sohngen presents groundbreaking work on methane-using and methane-producing bacteria. This is the first proof that methane can serve as an energy and carbon source. Sohngen, N. L. 1906. Ueber Bakterien, welche Methan als Kohlenstoffnahrung and energiequelle gebrauchen. Zentralbl. Bakteriol. Parasitik. Abt. I. 15: 513-517. A newly appointed pathologist in the Panama Canal Zone, Samuel Darling, performs an autopsy on a patient with a disease resembling tuberculosis and an agent resembling Leishmania sp. He recognizes significant differences between the etiologic agent and Leishmania sp., and names the organism Histoplasma capsulatum, believing that it is a protozoan. It is now known to be a fungus. Darling, S. T. 1906. A protozoan general infection producing pseudo tubercules in the lungs and focal necroses in the liver, spleen, and lymph nodes. JAMA. 46: 1283-1285. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.4 [PDF]

1907 Erwin Smith and C.O. Townsend discover that the cause of crown galls is a bacterium called Agrobacterium tumefaciens. Smith, Erwin, and C.O.1907. Townsend. A plant tumour of bacterial origin. Science 25: 671-673

1909 Howard Ricketts shows that Rocky Mountain spotted fever is caused by an organism that is intermediate in size between an virus and a bacterium. This organism, Rickettsia, is transmitted by ticks. Ricketts dies from typhus, another rickettsial disease, in 1910. Ricketts, H. 1909. A micro-organism which apparently has a specific relationship to Rocky Mountain spotted fever. J. Am. Med. Soc. 52: 379-380. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.8 [PDF] Sigurd Orla-Jensen proposes that physiological characteristics of bacteria are of primary importance in their classification. A primary example is a monograph he later publishes on lactic acid bacteria that establishes the criteria for assignment. Orla-Jensen, S. 1909. Die Hauptlinien des Naturlichen Bakterien-Systems. Centralblatt fur Bakteriologie. Section 2, XXII: 305-346. Carlos Chagas discovers the trypanosome, which he named Trypanosoma cruzi, and its mode of transmission, via reduviid bugs, as the cause of the human disease named for him. Chagas, C. "Ueber eine neue Trypanosomiasis des Menschen." Mem. Inst. Oswaldo Cruz 1:158-218

1910 Charles Henry Nicolle demonstrates that typhus fever is transmitted from person to person by the body louse. This information was used in both world wars to reduce the incidence of typhus. Nicolle is awarded the Noble Prize in Medicine and Physiology in 1928 1928 Nobel Prize Nicolle, C. H., C. Compte, and E. Conseil. 1910. Experimental Transmission of Exanthematous Typhus by body lice (Pediculus vestimenti). Ann. Past. Inst. 24: 261-267. Raimond Sabouraud summarizes about twenty years of his systematic and scientific studies of dermatophytes and dermatophytoses in a classic treatise, Les Teinges. He introduces a medium for the growth of pathogenic fungi. Sabouraud, R. 1910. Maladies du Cuir Chevelu III. Maladies Cryptogamiques. Les Teinges. Masson et Cie.

1911 Francis Peyton Rous discovers a virus that can cause cancer in chickens by injecting a cell free filtrate of tumors. This is the first experimental proof of an infectious etiologic agent of cancer. In 1909 a farmer brought Rous a hen that had a breast tumor. Rous performed an autopsy, extracted tumor cells and injected them in other hens, where sarcoma developed. Rous is awarded the Noble Prize in Medicine and Physiology in 1966 1966 Nobel Prize Rous, Peyton. 1911. Transmission of a malignant growth by means of a cell free filtrate. JAMA. 56: 198. Rous, Peyton. 1911. A sarcoma of the fowl transmissable by an agent separable from the tumor cells. J. Ex. Med. 13:397-411

1912 Paul Ehrlich announces the discovery of an effective cure (Salvarsan) for syphilis, the first specific chemotherapeutic agent for a bacterial disease. Ehrlich was a researcher in Koch’s lab, where he worked on immunology. In 1906 he became head of the Research Institute for Chemotherapy. He sought an arsenic derivative. The 606th compound worked. He brought news of the treatment to London, where Fleming became one of the few physicians to administer it. Ehrlich, P. 1912. Ueber Laboratoriumsversuche und klinische Erprobung von Heilstoffen. Chem. Ztg. 36: 637-638.

1915 The first discovery of bacteriophage, by Frederick Twort. Twort’s discovery was something of an accident. He had spent several years growing viruses and noticed that the bacteria infecting his plates became transparent. Twort, F. 1915. An investigation on the nature of ultra-microscopic viruses. Lancet, 2: 1241-1243. Chaim Weizmann, using the knowledge of Pasteur’s discovery that yeast ferments sugar, uses Clostridium acetobutylicum to produce acetone and butyl alcohol. These were essential to the British munitions program during World War I. Weizmann, C. 1915. British patent, 845. McCrady establishes a quantitative approach for analyzing water samples for coliforms using the most probable number, multiple-tube fermentation test. The test is based on the ability of coliforms to grow in selective broth at 35=F8C producing acid or gas within 24 to 48 hours. The number of coliforms and the 95% confidence limit can be determined using MPN tables for the volumes and number of fermentation tubes used McCrady, M.H. "The Numerical Interpretation of Fermentation Tube Results." J. Infect. Dis. 17:183

1917 Felix d'Herrelle independently describes bacterial viruses and coins the name "bacteriophage." Felix d’Herrelle: His Life and Work and the Foundation of a Bacteriophage Reference Center, ASM News 48, 1982. p.297 [PDF] D’Herrelle, F. 1917. Sur un microbe invisible antagoniste des bacilles dysenteriques. Comp. rend. Acad. Sci. 165: 373-375.In Milestones in Microbiology: 1556 to 1940, translated and edited by Thomas D. Brock, ASM Press. 1998, p157  [PDF] J. N. Currie discovers how to produce citric acid in large quantities from the mold Aspergillus niger-by employing a growth limiting medium rich in iron. Currie, J. N. 1917. The citric acid fermentation of Asperigillus niger. J. Bio. Chem. 31: 15-37.

1918 Alice Evans establishes that members of the genus Brucella. are responsible for the diseases of Malta Fever, cattle abortion, and swine abortion. She reports that the bacteria are bacilli and not micrococci. Evans, A. 1918. Further studies on Bacterium abortus and related bacteria. II. A comparison of Bacterium abortus with Bacterium bronchisepticus and with the organism that causes Malta Fever . J. Infect. Dis. 22: 580-593.

1919 Theobald Smith and M. S. Taylor describe the microbe, Vibrio fetus n. sp., responsible for fetal membrane disease in cattle. Smith and His Presidential Address to the Society of American Bacteriologists, ASM News 47, 1981, p.231 [PDF] Theobald Smith, 1859-1934: A Fiftieth Anniversary Tribute, ASM News 50, 1984. p.577 [PDF] Smith, T. and M. S. Taylor. 1919. Some morphological and biological characters of the Spirilla (Vibrio fetus, n. sp.) associated with the disease of the fetal membranes in cattle. J. Exp. Med. 30: 299-311. James Brown uses blood agar as a medium to study the hemolytic reactions for the genus Streptococcus and divides it into three types, alpha, beta, and gamma. Brown, J.H. 1919. The use of blood agar for the study of streptococci. Rockefeller Institute for Medical Research Monograph No.9. The Rockefeler Institute for Medical Research, New York.

1920 The SAB committee presents a report on the Characterization and classification of Bacterial Types that becomes the basis for the classic work of D. H. Bergey, later published in 1923.

1923 Michael Heidelberger and O. A. Avery show that carbohydrates from the pneumococcus can serve as virulence antigens and are serologically specific. This overturns the current wisdom that only proteins or glycoproteins are antigenic. Heidelberger, M. and O. T. Avery. 1923. The soluble specific substances of pnuemococcus, J. Exp. Med. 38: 73-79.

1924 George and Gladys Dick describe the "Dick test", a skin test for scarlet fever. They purify a soluble extoxin from hemolytic Streptococccus pyogenes and use it as a diagnostic. They use Koch’s postulates to show that scarlet fever is caused by streptocoocci, recover the bacteria from all cases of the disease and infect others with cultures of the bacterium. Dick, G. and G. Dick. 1924. A skin test for susceptibility to scarlet fever. JAMA. 82: 265-266. Albert Calmette and Camille Guerin introduce a living non-virulent strain of tuberculosis (BCG) to immunize against the disease. This is the result of work begun in 1906 on attenuating a strain of bovine tuberculosis bacillus. More than 200 subcultures were grown before the resulting strain was tested. Calmette, A. and C. Guerin. 1924. Vaccination of bovines against tuberculosis. Ann. Inst. Pasteur. 38: 371-398. Albert Jan Kluyver publishes an article "Unity and Diversity in the Metabolism of Micro-organisms" that demonstrates common metabolic events occur in different microbes. The processes he refers to are oxidation, fermentation and biosynthesis. Klyuver also points out that life on earth without microbes would not be possible. Klyuver, A. J. 1924. Eenheid en verscheidenheid in de stofwisseling der microben. Chem. Weekbl. 21, 266-80. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.188 [PDF] and also In Milestones in Microbiology: 1556 to 1940, translated and edited by Thomas D. Brock, ASM Press. 1998, p247 [PDF]

1926 Thomas Rivers distinguishes between bacteria and viruses, establishing virology as a separate area of study. This paper was published after he presented it at an SAB meeting held in December of 1926. Rivers, T. 1927. Filterable viruses. A critical review. J. Bact. 14: 217. Albert Jan Kluyver and Hendrick Jean Louis Donker propose a universal model for metabolic events in cells based on a transfer of hydrogen atoms. The model applies to aerobic and anaerobic organisms. Kluyver, A. J. and H. J. L. Donker. 1926. Die einheit in der biochemie. Chem. Zelle Geweke. 13: 134-190.   Everitt Murray isolates from rabbits a bacterium that is responsible for listeriosis in man. The organism can grow at low temperatures and frequently is found in food. He names it Bacterium monocytogenes. It is later renamed Listeria monocytogenes. Murray, E.G.D., R. A. Webb, and M.B.R. Swann. 1926. A disease of rabbits characterized by a large mononuclear leucocytosis, caused by a hitherto undescribed bacillus Bacterium monocytogenes. J. Pathol. Bacteriol. 29:407-39

1928 Frederick Griffith discovers transformation in bacteria and establishes the foundation of molecular genetics. He shows that injecting mice with a mixture of live, avirulent, rough Streptococcus pneumoniae Type I and heat-killed, virulent smooth S. pneumoniae Type II, leads to the death of the mice. Live, virulent, smooth S. pneumoniae Type II are isolated from the dead mice. Not until the 1930’s, did Avery, Macleod and McCarty take up Griffith’s work and try to explain the results. Griffith, F. 1928. The significance of pneumococcal types. J. Hyg. 27, 113-159.

1929 Alexander Fleming publishes the first paper describing penicillin and its effect on gram positive microorganisms. This finding is unique since it is a rare example of bacterial lysis and not just microbial antagonism brought on by the mold Penicillium. Fleming kept his cultures 2-3 weeks before discarding them. When he looked at one set he noticed that the staphylococcus bacteria seemed to be dissolving. The mold that contaminated the culture was a rare organism called penicillium. He left the culture on the lab bench and went on vacation. While he was away the culture was subjected to a cold spell followed by a warm one – the only conditions under which the discovery could be made. When penicillin is finally produced in major quantities in the 1940s, its power and availability effectively launch the "Antibiotics Era," a major revolution in public health and medicine. With Florey and Chain, Fleming is awarded the Noble prize in Medicine and Physiology in 1945 1945 Nobel Prize Fleming, A. 1929. On the antibacterial action of cultures of a Penicillium, with a special reference to their use in the isolation of B. influenze. Brit. J. Exp. Path. 10: 226-236. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.98 [PDF] and also In Milestones in Microbiology: 1556 to 1940, translated and edited by Thomas D. Brock, ASM Press. 1998, p185  [PDF] In Praise of Antibiotics, ASM News 65, 1999. p.304

1930 Henning Karstrom begins to identify the phenomena of enzyme adaptation and of constitutive synthesis, in which synthesis of an enzyme either is increased in response to the presence of the substrate of the environment or is independent of the growth medium. His work is based on studies of carbohydrate metabolism in Gram negative enteric bacteria. Karstrom, H. 1930. .Ann. Ueber die enzymbildung in Bakterien. Thesis, Helsinfors.

1931 Rene Dubos working with Oswald Avery discovers Bacillus brevis, an organism that breaks down the capsular polysaccharide of Type III S. pneumocci and protects mice against pneumonia. Dubos, R. and O. T. Avery. 1931. Decomposition of the capsular polysaccharide of pneumonococcus type III by a bacterial enzyme. J. Exper. Med. 54: 51-71. C. B. van Niel shows that photosynthetic bacteria use reduced compounds as electron donors without producing oxygen. Sulfur bacteria use H2S as a source of electrons for the fixation of carbon dioxide. He posits that plants use water as a source and release oxygen.At this time Van Niel begins the first independent ?general microbiology? course at the Hopkins Marine Station in Pacific Grove, California. van Niel Remembered, ASM News 53, 1987. p.75 [PDF] van Neil, C. B. 1931. On the morphology and physiology of the purple and green sulfur bacteria. Arch. Mikrobiol. 3: 1-112. Margaret Pittman identifies variation, such as encapsulated forms, and type specificity, such as type b, of the Haemophilus influenzae as determinants of pathogenicity. Pittman, M. 1931. Variation and type specificity in the bacterial species Haemophilus influenzae. J. Exp. Med. 53: 471-492. William Joseph Elford discovers that viruses range in size from large protein molecules to tiny bacteria. Elford, W. J. 1931. A new series of graded colloidal membranes suitable for general bacteriological use, especially in filterable virus studies. J. Pathol Bacteriol. 34: 505-521. Alice Woodruff and Ernest Goodpasture devise a technique of cultivating viruses in eggs. Woodruff, A. and E. Goodpasture. 1931. The susceptibility of the chorio-allantoic membrane of chick embryos to infection with the fowl-pox virus. Am. J. Path. 7: 209-222.

1932 R. Stewart and K. Meyer describe the isolation of Coccidiodes immitis from soil located near where several patients were thought to have become infected. This establishes that the soil is a reservoir for the fungus. Stewart, R. A. and K. F. Meyer. 1932. Isolation of Coccidiodes immitis (Stiles) from the soil. Proc. Soc. Exper. Biol. & Med. 29: 937-938.

1933 Rebecca Lancefield describes a method of producing streptococcal antigens and sera for use in precipitin tests and suggests that this approach can be used epidemiologically to identify the probable origin of a given strain. Rebecca Craighill Lancefield, Pioneer Microbiologist, ASM News. 41,1975. p.805 [PDF] Lancefield, R. C. 1933. A serological differentiation of human and other groups of hemolytic streptococci. J. Exper. Med. 57: 571-595.

1934 Ladislaus Laszlo Marton is the first to examine biological specimans with the electron microscope, which achieves magnifications of 200-300, 000x. Later in 1937, he publishes the first electron micrographs of bacteria. Marton, L. 1934. La microscopie electronique des onjectes biologiques. Bull. Acad. Belg. Cl. Sci. 20: 439-466. Alice Evans accomplishes the first typing of a strain of bacteria with bacteriophage. Evans, A. 1934. Streptococcus bacteriophage: A study of four serological types. Public Health Rep. 49: 1386-1401. William de Monbreun describes the dimorphic nature of Histoplasma capsulatum after being surprised by the growth of a mold from patient tissues displaying yeasts. de Monbreun, W. A. 1934. The cultivation and cultural characteristics of Darling’s Histoplasma capsulatum. Am. Jour. Trop. Med. 14: 93-125.

1935 Gerhard J. Domagk uses a chemically synthesized antimetabolite, Prontosil, to kill Streptococcus in mice. It is later shown that Prontosil is hydrolyzed in vivo to an active compound, sulfanilamide. One of the first patients to be treated with Protonsil was Domagk’s daughter who had a streptococcal infection that was unresponsive to other treatments. When she was near death, she was injected with large quantities of Protonsil and she made a dramatic recovery. Domagk is awarded the Nobel Prize in Medicine and Physiology in 1939 1939 Nobel Prize Domagk, G. J. 1935. Ein Beitrag zur Chemotherapie der bakteriellen infektionen. Dtsch. med. Wochenschr. 61: 250-253. In Milestones in Microbiology: 1556 to 1940, translated and edited by Thomas D. Brock, ASM Press. 1998, p195 [PDF] Wendell Stanley crystallizes tobacco mosaic virus and shows it remains infectious. However, he does not recognize that the infectious material is nucleic acid and not protein. Together with Northrop and Sumner, Stanley is awarded the Nobel Prize in Chemistry in 1946 1946 Nobel Prize Stanley, W. 1935. Isolation of a crystalline protein possessing the properties of tobacco-mosaic virus. Science. 81: 644-654.In Milestones in Microbiology: 1556 to 1940, translated and edited by Thomas D. Brock, ASM Press. 1998, p160  [PDF] William A. Hinton, chief of the Wasserman laboratory at Harvard, publishes the first major text on syphilis, Syphilis and its Treatment, which includes reference to the Davies-Hinton test to detect syphilis in spinal fluids.

1936 J. D. Bernal, F. C. Bauden, N. W, Pirie, and I. Pankuchen demonstrate that isolated preparations of tobacco mosaic virus contain phosphorus as a component of a phospho-ribonucleic acid. They also isolate ribonucleic acids.this challenges the claim by Stanley that the TMV is composed only of protein Bauden, F. C. , N. W. Pirie, J. D. Bernal, and I. Fankuchen. 1936. Liquid crystalline substances from virus infected plants. Nature 138:1051-1052. Harland Wood and Chester Werkman show that CO2 is consumed by Propionibacterium arabinosum duirng the fermentation of glycerol. This is the first report of carbon dioxide fixation by a heterotrophic bacterium. H.G. Wood and C.H. Werkman. 1936. The utilization of CO2 in the dissimilation of glycerol by propionic acid bacteria. Biochem. J. 30:48-53. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.202 [PDF]

1938 Field tests of Max Theiler’s vaccine against yellow fever prove successful. The vaccine is based on a mouse passaged virus. The Rockefeller Foundation manufactures more than 28 million doses by 1947. Theiler was awarded the Nobel Prize in Medicine and Physiology in 1951 1951 Nobel Prize Theiler, M. and H. H. Smith. 1937. J. Exp. Med. 65: 787. Smith, H. H., H. A Penna, and A. Paoliello. 1938. Yellow fever vaccination with cultured virus (17D) without immune serum. Am. J. Trop. Med. 18: 437-468.

1939 E. L. Ellis and Max Delbruck establish the concept of the one-step viral growth cycle for a bacteriophage active against E. coli. E.L Ellis and M.L. Delbruck. 1939. The growth of bacteriophage.J.Gen.Physiol. 22:36584. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p448 [PDF]

1940 Pathologist Howard Florey and biochemist Ernest Chain produce an extract of penicillin, the first powerful antibiotic. They isolate the antibiotic from Fleming’s mold cultures and demonstrate that it can cure infections in animals. Florey and Chain began their research by focusing on the discovery by Fleming of lysozyme. In the course of reviewing Fleming’s papers, Chain read the description of penicillin. With Fleming, Florey and Chain are awarded the Nobel Prize in Medicine and Physiology in 1945 1945 Nobel Prize Chain, E., H. W. Florey, A. D. Gardner, N. G. Heatley, M. A. Jennings, J. Orr-Ewing, and A. G. Sanders Penicillin as a chemotherapeutic agent. Lancet 2: 226-228.  In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.112 [PDF] Ernest Chain and E.P. Abraham describe a sustance from E. coli that can inactivate penicillin. It was the first bacterial product that was recognized to mediate resistance to an antibacterial agent. Abraham, E.P. and E. Chain. 1940. An enzyme from bacteria able to destroy penicillin. Nature 3713:837. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.115 [PDF] Helmuth Ruska uses an electron microscope to obtain the first pictures of a virus. Ruska, H. 1940. Die Sichtbarmachung der BakteriophagenLyse im Ubermikroskop. Naturwissenschaaften. 28: 45-6. Charles E. Smith and his colleagues demonstrate the usefulness of a tuberculin-like preparation of Coccidiodes immitis in detecting prior exposure to the fungus. This preparation allowed for the delineation of the endemic area for the fungus. Smith C. E. 1940. Epidemiology of acute coccidioidomycosis with erythema nodoosum ("San Joaquin" or "Valley Fever"). Am. Jour. Pub. Health 30: 600-611. Donald O. Woods describes the relation of para-aminobenzoic acid to the mechanism of action of sulfanilamide, which was used by Domagk to treat Streptococcal infections in mice. Woods, D. O. 1940. The relation of p-aminobenzoic acid to the mechanism of the action of sulphanilamide. Brit. J. Exp. Path. 21: 74-90.  In Milestones in Microbiology: 1556 to 1940, translated and edited by Thomas D. Brock, ASM Press. 1998, p199 [PDF] Selman Waksman and H. Boyd Woodruff discover actinomycin, the first antibiotic obtained pure from an actinomycete, leading to the discovery of many other antibiotics from that group of microorganisms. After Renee Dubos discovered two antibacterial substances in soil, Waksman decided to focus on the medicinal uses of antibacterial soil microbes. Waksman, S. and H. B. Woodruff. 1940. Bacteriostatic and bactericidal substances produced by soil Actinomyces. Proc. Soc. Explt. Biol. Med. 45: 609-614.

1941 George Beadle and Edward Tatum jointly publish a paper on their experiments using the fungus Neurospora crassa to establish that particular genes are expressed through the action of correspondingly specific enzymes. The first gene to be identified controlled the synthesis of an enzyme in a series that led to generation of niacin. This report is the genesis of the "one gene-one enzyme" concept. They chose Neurospora because it grew and reproduces quickly. They grew Neurospora on a culture medium that contained nutrients essential to its growth and then irradiated the colonies with x-rays. Some colonies that grew but failed to thrive. Only after adding vitamin B6 did the irradiated organisms begin to grow normally. By mating the defective organisms with normal organisms they showed the defect was inherited as a Mendelian recessive gene. With Lederberg, Beadle and Tatum are awarded the Nobel Prize in Medicine and Physiology in 1958 1958 Nobel Prize Beadle, G. and E. Tatum. 1941. Genetic control of biochemical reactions in Neurospora. Proc. Nat. Acad. Sci. 27: 499-506. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.308 [PDF] Charles Fletcher first demonstrates that penicillin is non-toxic to human volunteers, by injecting a police officer suffering with a lethal infection. Abraham, E. P., E. Chain, C. M. Fletcher, A. D. Gardner, N. G. Heatley, M. A. Jennings, and H. W. Florey. 1941. Further observations on penicillin. Lancet 2: 177-188. McFarlane Burnet proposes that descendents of antigen reacting cells produce antibodies specific to the antigen. Burnet, F. M., M. Freeman, A. Y. Jackson and D. Lush. 1941. The Production of antibodies. (Monographs of the Walton and Eliza Hall Institute No. 1.) London: Macmillan & Co. Ltd. George Hirst demonstrates that influenza virus agglutinates red blood cells. Since the cell attachment proteins of most viruses also agglutinate red blood cells, this property provides a rapid, accurate and quantitative method of counting virus particles. Hirst, G.K. 1941. The agglutination of red blood cells by allantoic fluid chick embryos infected with influenza virus. Science. 94:22-23

1942 Selman Waksman suggests the word "antibiotic" (coined in 1889 by P. Vuillemin) after Dr. J. E. Flynn, the editor of Biological Abstracts asked him to suggest a term for chemical substances, including compounds and preparations that are produced by microbes and have antimicrobial properties. Although there is no journal citation, Waksman recalled the incident in his book The Antibiotic Era. Because the word was accepted quickly and the meaning became confused, Waksman published a comprehensive definition in 1947: "an antibiotic is a chemical substance produced by microbes that inhibits the growth of and even destroys other microbes (and is active in dilute solutions)" was added later. Albert H. Coons, H.J. Creech, R.N. Jones, and E. Berliner use a fluorescent antibody to find antigens of pneumococci in human tissue. They chemically bind a fluorescent group to antipneumococcus type III antibody and use a fluorescence microscope to locate the antibody in histologic sections. They also provided some basic data on sensitivity and specificity. A.H. Coons, H.J. Creech, R.N. Jones, and E. Berliner. Demonstration of pneumoccocal antigen in tissues by use of fluorescent antibody. 1942 J. Immunol. 45:159-70. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999,p.12 [PDF] Thomas Anderson and Salvador Luria photograph bacteriophages with the aid of an electron microscope, confirming earlier work by Ruska. They demonstrate that an E. coli T2 phage has a head and a tail. Luria, S. E. and T. F. Anderson. 1942. The identification and characterization of bacteriophages with the electron microscope. Proc. Natl. Acad. Sci. USA. 28: 127-130. Jules Freund and Katherine McDermott identify adjuvants, such as paraffin oil, that can significantly boost antibody production. The preparation is composed of heat killed tubercule bacilli in a water-in-oil emulsion. Freund, J. and K. McDermott. 1942. Sensitization to horse serum by means of adjuvants. Proceedings of the Society for Experimental Biology and Medicine 49: 548-553.

1943 Salvador Luria and Max Delbruck provide a statistical demonstration that inheritance in bacteria follows Darwinian principles. Particular mutants, such as viral resistance, occur randomly in bacterial populations, even in the absence of the virus. More importantly, they occur in small numbers in some populations and in large numbers in other cultures. The results, known as fluctuation analysis, show that resistance occurs before exposure to the phage and argues against the adaptation hypothesis of mutations. With Delbruck and Hershey, Luria is awarded the Nobel Prize in Medicine and Physiology in 1969 1969 Nobel Prize Luria, S. E. and M. Delbruck. 1943. Mutations of bacteria from virus sensitivity to virus resistance. Genetics. 28: 491-511. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.318 [PDF] R. E. Hungate describes an anaerobic cellulose digesting bacterium in cattle. Hungate, R. E. 1943. Further experiments on cellulose digestion by the protozoa in the rumen of cattle. Biol. Bull. 84: 157-163.

1944 W. H. Feldman and H. C. Hinshaw at the Mayo Clinic are the first to demonstrate successful treatment of tuberculosis with streptomycin. Feldman, W. H. and H. C Hinshaw. 1944. Effects of streptomycin on experimental tuberculosis in guinea pigs. A preliminary report. Proc. Staff Meet. , Mayo Clin. December 24, 1944. 19: 593-599. Oswald Avery, Colin MacLeod, and Maclyn McCarty show that DNA is the transforming material in cells. They use the observations of Griffith and show the transformation of Streptococcus pneumoniae from an avirulent phenotype to a virulent phenotype is the result of the transfer of DNA from dead smooth organisms to live rough ones. They also show that the transforming principle is destroyed by pancreatic deoxyribonuclease, which hydrolyzes DNA, but is not affected by pancreatic ribonuclease or proteolytic enzymes. Macleod was Avery’s research assistant until 1941. By the time he left, he and Avery suspected that the vital substance in bacterial transformation was DNA. McCarty confirmed their hypothesis. Oswald T. Avery Collection Avery, O. T., C. M. Macleod, and M. McCarty. 1944. Studies on the chemical nature of the substance inducing transformation of pneumonococcal types. Induction of transformation by a deoxyribo-nucleic acid fraction isolated from pnuemococcus type III. J. Exp. Med. 79: 137-157. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.116 [PDF] Albert Schatz, E. Bugie, and Selman Waksman discover streptomycin, soon to be used against tuberculosis. Streptomycin has the same specific antibiotic effect against gram negative microorganisms as penicillin does on gram positives. Waksman is awarded the Nobel Prize in Medicine and Physiology in 1952 1952 Nobel Prize Schatz, A., E. Bugie, and S. A. Waksman. 1944. Streptomycin, a substance exhibiting antibiotic activity against gram-positive and gram-negative bacteria. Proc. Soc. Exp. Biol. Med. 55: 66-69.

1945 Salvador Luria and Alfred Day Hershey demonstrate that bacteriophages mutate, thereby making it difficult to develop immunity to such things as flu and colds. They also introduce criteria for distinguishing mutations from other modifications. With Delbruck and Luria, Hershey is awarded the Nobel Prize in Medicine and Physiology in 1969 1969 Nobel Prize Luria, S. E. 1945. Mutation of bacterial viruses affecting their host range. Genetics 30: 84-99. Colin MacLeod, Richard Hodges, Michael Heidelberger, and William Bernard show that an isolated capsular polysaccharide can immunize against Nesseria meningtitis. The vaccine is finally approved in 1977 after extensive international testing. MacLeod, C., R. Hodges, M. Heidelberger, and W. Bernhard. 1945. Prevention of pneumococcal pneumonia by immunization with specific capsular polysaccharides. J. Exp. Med. 82: 445-465.

1946 Joshua Lederberg and Edward L. Tatum publish on conjugation in bacteria. The proof is based on the generation of daughter cells able to grow in media that cannot support growth of either of the parent cells. Their experiments showed that this type of gene exchange requires direct contact between bacteria. At the time Lederberg began studying with Tatum, scientists believed that bacteria reproduced asexually, but from the work of Beadle and Tatum, Lederberg knew that fungi reproduced sexually and he suspected that bacteria did as well. Lederberg, J. and E. L. Tatum. 1946. Gene recombination in Eschericia coli. Nature. 58: 558.

1947 Armin Braun shows that A. tumefaciens introduces a factor into plant cells that permanently transforms them into cancer cells. Braun, A.C. 1947. Thermal studies on the factors responsible for tumour initiation in crown gall. Am. J. Botany 34:234-240

1948 Mary Shorb’s Lactobacillus lactis assay is employed at Merck & Co. to guide purification and crystallization of vitamin B12 from Streptomyces griseus culture. B12 is applied to the treatment of pernicious anemia in man, and as the animal protein factor, the promotion of growth in farm animals. Shorb, M. S. 1948. Activity of vitamin B12 for the growth of Lactobacillus lactis. Science 107: 397.

1949 Microbiologist John Franklin Enders, virologist Thomas H. Weller and physician Frederick Chapman Robbins together develop a technique to grow polio virus in test tube cultures of human tissues. This approach gave virologists a practical tool for the isolation and study of viruses. . Enders, Weller, and Robbins were awarded the Nobel Prize in Medicine and Physiology in 1954 1954 Nobel Prize Enders, J. F., T. H. Weller, and F. C. Chapman. 1949. Cultivation of the Lansing strain of poliomyelitis virus in cultures of various human embryonic tissues. Science 109: 85-87. Medical mycologist Chester Emmons confirms what many had suspected, that Histoplasma capsulatum resides in soil, by culturing the organism from rat burrows. Emmons, C. W. 1949. Isolation of Histoplasma capsulatum from soil. U. S. Pub. Hlth. Rep. 64: 892-896.

1950 Robert Hungate publishes a description of the roll-tube culture technique, which permits culturing anaerobes. The procedure eliminates oxygen by underlaying with it with carbon dioxide and then introducing agar. This is a key advance in studying anaerobic bacteria from cow rumen.. Hungate, R. E. 1950. The anaerobic mesophilic cellulolytic bacteria. Bact. Rev. 14: 1-49. Andre Lwoff and Louis Siminovitch demonstrate that irradiation with ultra-violet light terminates the lysogenic state in bacteria and permits bacteriophage to replicate and then lyse the host cell. This opens the field of lysogeny to molecular analysis. With Jacob and Monod, Lwoff is awarded the Nobel Prize in Medicine and Physiology in 1965 1965 Nobel Prize Genetics at the Institute Pasteur: Substance and Style, ASM News 53, 1987. p.547 [PDF]. A. Lwoff, L. Siminovitch, and N. Kjeldgaard. 1950. Comptes Rendus. 231:190-91. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.470 [PDF]

1952 Joshua Lederberg and Esther Lederberg publish their replica plating method and provide firm evidence that mutations in bacteria yielding resistance to antibiotics and viruses are not induced by the presence of selective agents. Replica plating or transfer of specific physical isolates allows for rapid screening of large numbers of genetic markers. With Beadle and Tatum, J. Lederberg is awarded the Noble Prize in Medicine and Physiology in 1958 1958 Nobel Prize Joshua Lederburg Collection Interview with Joshua Lederberg - (requires ISDN+ modem and RealPlayer) Bacterial Variation Since Pasteur, ASM News 58, 1992. p.261 [PDF] Lederberg, J. and E. Lederberg. 1952, Replica plating and indirect selection of bacterial mutants. J. Bact. 63: 399-406. Joshua Lederberg uses the term plasmid to describe extranuclear genetic elements that replicate autonomously. Lederberg, J. 1952. Cell genetics and hereditary symbiosis. Physiol. Rev. 32: 403-430. Joshua Lederberg and Norton Zinder report on transduction, or transfer of genetic information by viruses. They show that a phage of Salmonella typhimurium can carry DNA from one bacterium to another. Zinder, N and J. Lederberg, 1952. Genetic exchange in Salmonella. J. Bact. 64: 679-699. Renato Dulbecco shows that single particles of an animal virus can produce plaques. With Baltimore and Temin, Dulbecco is awarded the Nobel Prize in Mediicne and Physiology in 1975 1975 Nobel Prize Dulbecco, R. 1952. Production of plaques in monolayer tissue cultures by single particles of an animal virus. Proc. Natl. Acad. Sci. USA. 38: 747-752. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.494 [PDF] Coming of Age of Animal Virology, ASM News 65, 1999. p.334 Marvin Bryant isolates spirochetes from cattle rumen. Bryant, M. 1952. The isolation and characteristics of a spirochete from the bovine rumen. J. Bacteriol. 64: 325-335. Alfred Hershey and Martha Chase suggest that only DNA is needed for viral replication. They use radioactive isotopes 35S to track protein and 32P to track DNA and show that progeny T2 bacteriophage isolated from lysed bacterial cells have the labeled nucleic acid. Further, most of the labeled protein doesn’t enter the cells but remains attached to the bacterial cell membrane. Hershey, A. D. and M. Chase. 1952. Independent functions of viral protein and nucleic acid in growth of bacteriophage. J. Gen. Physiol. 36: 39-56. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p. 474 [PDF] Salvador Luria and Mary Human, and independently Jean Weigle, describe a non-genetic heritable variation in bacteriophage imposed on the host in which it was grown. They call this phenomenon host-controlled modification and note that the incorrectly modified phage are "restricted" in the inappropriate host. This later leads to study of bacterial systems of restriction and modification, and eventually the discovery of restriction endonucleases. Luria, S.E. and M. Human. 1952. A nonhereditary, host-induced variation of bacterial viruses. J. Bact. 64: 557-569. William Hayes proposes that bacterial conjugation involves the unidirectional transfer of genes from a donor to a recipient cell. Until then, most microbiologists believed that there was either a fusion of cells or an exchange of genetic information. Contemporaneous with Cavalli, Lederberg, and Lederberg, he also shows that a fertility factor, F, a non-chromosomal plasmid, is present only in donor cells. Lederberg, J., L.L. Cavalli, and E. M. Lederberg. 1952. Sex compatibility in Escherichia coli. Genetics 37: 720-730. Hayes, W. 1952. Recombination in Bact.coli. K-12: unidirectional transfer of genetic material. Nature 169: 118-119. James T. Park and Jack L. Strominger conclude that penicillin acts by inhibiting murein synthesis in the cell wall. This is the first discovery of the mode of action of a natural antibiotic. Park, J. T. 1952. J. Biol. Chem. 194: 877, 885, 897.

1953 Francis Crick and Maurice Wilkins, together with James Watson, describe the double-helix structure of DNA. The chemical structure is based on x-ray crystallography of DNA done by Rosalind Franklin. Crick, Wilkins and Watson are awarded the Nobel Prize in Medicine and Physiology in 1962 1962 Nobel Prize DNA Helix Turns 40, ASM News 60,1994. p.28 [PDF] Watson, J. D. and F. H. C. Crick, 1953. Molecular structure of nucleic acids: a structure for desoxyribonucleic acid. Nature 171: 737-738. Jonas Salk begins preliminary testing of polio vaccine. The vaccine is composed of three types of killed virus. Salk, J. E. 1953. Studies in human subjects on active immunization against poliomyelitis. A preliminary report of experiments in progress. JAMA. 151: 1081. Elizabeth Lee Hazen and Rachel Fuller Brown develop the first useful fungal antibiotic, NYSTATIN. The drug is developed through a long-distance collaboration with Brown in Albany and Hazen in New York City. Hazen, E. L., R. F. Brown, and A. Mason. 1953. Protective action of Fungicidin (Nystatin) in mice against virulence enhancing activity of oxytetracycline on Candida albicans. Antibiotics & Chemother. 3: 1125.

1955 H. Edwin Umbarger adds isoleucine to Escheria coli cells growing on minimal glucose and shows that synthesis of isoleucine by the cell is blocked. Arthur Pardee shows the same inhibition pattern with pyrimidines. This finding provides evidence for feedback inhibition. Umbarger, H. E., and B. Brown. 1955. Isoleucine and valine metabolism in Escherichia coli. Antagonism between isoleucine and valine. J. Bact. 70: 241-248. Pardee, A. D. 1955. Effect of energy supply on enzyme induction by pyramidine requiring mutants of Escherichia coli. J. Bact. 69: 233-239.

1956 Publication of The Microbe’s Contribution to Biology by A. J. Kluyver and C. B. Van Neil. The work hints at a future explosion of knowledge concerning the regulation of metabolism and its genetic machinery—A prophecy that will come true in less than two decades. Charles E. Smith and his colleagues, by correlating the results of the analysis of 39,500 sera of patients with coccidiodomycosis, establish the usefulness of serology in the diagnosis and prognosis of coccidiodomycosis. Smith, C. E., M. T. Saito, and S. A. Simmons. 1956. Pattern of 39500 serologic tests in coccidioidomycosis. JAMA 160: 546-552. D. L. D. Caspar and Rosalind Franklin independently show the location of the ribonucleic acid within the protein capsid in tobacco mosaic virus. Caspar, D. L. D. 1956. Radial density Distribution in the Tobacco Mosaic Virus particle. Nature 177: 928. Franklin, R. 1956. Location of the ribonucleic acid in the tobacco mosaic virus particle. Nature 177: 929. G. Schramm and A. Gierer show that RNA from tobacco mosaic virus is infectious and by itself can cause the disease and result in new viral particles.. Gierer, A. and G. Schramm. 1956. Infectivity of ribonucleic acid from tobacco mosaic virus. Nature 177: 702-702. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.502 [PDF]

1957 Seymour Benzer shows that recombination can occur between mutations within the same gene. He maps the mutations with the rII gene of phage T4 and demonstrates that genes are linear arrays of mutable sites. Benzer, S. 1955. Fine structure of a genetic region in bacteriophage. Proc. Natl. Acad. Sci. USA 41: 344-354. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p. 340 [PDF] Alick Isaacs and Jean Lindemann discover interferon, an antiviral protein produced by the body to fight viral infections. The first experiments take place with chick embryo tissue cultures infected with influenza virus. The interferon protects adjacent cells against the virus. Isaacs, A., and J. Lindenmann. 1957. Virus interference; I. The interferon. Proc. Roy. Soc. Series B 147: 258-267. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.506 [PDF] D. Carleton Gajdusek proposes that a slow virus is responsible for the wasting disease kuru. He shows that the course of the disease is similar to that of scrapie, which is transmitted among sheep. He also shows that kuru can be transmitted to chimpanzees.With Blumberg, Gajdusek is awarded the Nobel Prize in Medicine and Physiology in 1976 1976 Nobel Prize Gajdusek, D. C. and V. Zigas. 1957. Degenerative disease of the central nervous system in New Guinea. The endemic occurrence of "kuru" in the native population. N. Engl. J. Med. 257: 974-978. Heinz Fraenkal-Conrat demonstrates that viral RNA can act as a source of genetic information by mixing viral coat proteins and RNA from two viruses and showing that lesions on tobacco plants are entirely dependent on the source of RNA in the reassembled virus. Fraenkel-Conrat, H. and R. C. Williams. 1957. Virus reconstitution : combination of protein and nucleic acid from different strains. Biochim. Biophys. Acta. 24: 87. Shuko Kinoshita, S, Udaka, and M. Shimono discover that bacteria can be used to produce monosodium glutamate. This leads to a new industry; the microbial production of amino acids for human and animal nutrition as well as for food flavoring. Kinoshita, S., K. Tanaka, S. Udaka, and S. Akita. 1957. Proc. Intern. Symposium Enzyme Chem. 464-468. Francois Jacob and Elie Wollman provide evidence of the circular nature of the chromosome in Escherichia coli after analyzing data from interrupted mating experiments. Wollman, E. and F. Jacob. 1957. Sur les processus de conjugaison et de reconbinaison chez Escherichia coli. Ann. Inst. Pasteur 93: 323-339.

1958 The Soviet delegation to the World Health Organization proposes a global crusade to eradicate smallpox. Approved in 1959, the program finally begins in 1967. Joseph H. Burkhalter and Robert Seiwald make an essential contribution to the identification of antigens by developing the first antibody labeling agent, flourescein isothiocyanate (FITC). Widespread use of FITC catalyzed the generation of other labeling procedures such as the radio-immunoassay and enzyme-linked immuno-absorbant assay. Riggs, J. L., R. J. Seiwald, J. H. Burkhalter, et al. 1958. Isothiocyanate compounds as flourescent labeling agents for immune serum. Am. J. Path. 34: 1081-1097. Matthew Meselson and Franklin Stahl use density gradient equilibrium centrifugation to show that the two parental strands of DNA untwist during replication and combine with a newly synthesized daughter strand, just as predicted by Watson and Crick. Meselson, M. and F. Stahl. 1958. The replication of DNA in Escherichia coli. Proc. Natl. Acad. Sci. USA 44: 671-682. Ole Maaloe, Moselio Schaechter, and Nils O. Kjeldgard establish that bacteria can grow in a continuum of physiological states determined by the growth rate. This starts a new discipline, bacterial growth physiology. Schaechter, M., O. Maaloe, and N. O. Kjeldgard. 1958. Dependency on medium and temperature of cell size and chemical composition during balanced growth of Salmonella typhimurium. J. Gen. Microbiol. 19: 152.

1959 O. Sawada and others demonstrate that antibiotic resistance can be transferred between Shigella strains and Escherichia coli strains by extrachromosomal plasmids. The transfer does not involve either transformation or transduction. Ochiai, K., T. Yamanaka, K. Kimura, and O. Sawada. 1959. Nippon lji. 1861: 34. Arthur Pardee, Francois Jacob, and Jacque Monod show that the enzyme beta-galactosidase is induced by changes in culture conditions. This is the first example of negative control of induction and is due to the action of a repressor protein. This set the stage for other experiments aimed at further delineating the interaction of a regulatory protein with a site on DNA to control the expression of other genes. Pardee, A., F. Jacob, and J. Monod. 1959. The genetic control and cytoplasmic expression of ‘inducibility’ in the synthesis of beta-galactosidase by E. coli. J. Mol. Biol. I: 165. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.368 [PDF] Maxwell Finland, W. F. Jones, Jr., and M. W. Barnes comment on the development of antibiotic resistance, as a response to the introduction of antibacterial agents. Hirsch, H. and M. Finland. 1959. Antibacterial activity of serum of normal subjects after oral doses of demethylchlortetracycline, chlortetracycline and oxtetracycline. N. Engl. J. Med. 260: 1099-1104. Peter Mitchell proposes the chemiosmotic theory in which a molecular process is coupled to the transport of protons across a biological membrane. He argues that this principle explains ATP synthesis, solute accumulations or expulsions, and cell movement (flagellar rotation). Mitchell is awarded the Nobel Prize in Chemistry in 1978 1978 Nobel Prize Peter Mitchell and the Chemiosmotic Theory, ASM News 63, 1997. p.13 [PDF] Mitchell, P., and J. Moyle. 1959. Permeability of the envelopes of Staphylococcus aureus to some salts, amino acids and non-electrolytes. J. Gen. Microbiol. 20: 434-441. R.L. Riley, C.C. Mills, and W. Nyka prove that pulmonary tuberculosis is disseminated as an aerosol and so affected individuals are contagious. They used guinea pigs as the animal model and exposed them to air from patients with active pulmonary tuberculosis. R.L. Riley, C.C. Mills, W. Nyka, N. Weinstock, P.B. Storey, L.U. Sultan, M.C. Riley, and W.F. Wells. Aerial disseminations of pulmonary tuberculosis. A two-year study of contagion in a tuberculosis ward. 1959. Amer. J. Hyg. 70:185-96 In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.26 [PDF]

1960 Arthur Kornberg demonstrates DNA synthesis in cell-free bacterial extracts and later shows that a specific enzyme is necessary to link the nucleotide precursors of DNA. The enzyme works only in the presence of a DNA template. Kornberg, A. 1960. Biologic synthesis of deoxyribonucleic acid. Science 131: 1503-1508. Francois Jacob, David Perrin, Carmen Sanchez and Jacques Monod propose the operon concept for control of bacteria gene action. Jacob and Monod later propose that a protein repressor blocks RNA synthesis of a specific set of genes, the lac operon, unless an inducer, lactose, binds to the repressor. With Lwoff, Jacob and Monod are awarded the Noble Prize in Medicine and Physiology in 1965 1965 Nobel Prize Jacob, F., D. Perrin, C. Sanchez, and J. Monod. 1960. L’operon: Groupe de genes a l’expression coordonne par un operateur. Compt. Rendu. Acad. Sci. 245: 1727-`729. The oral polio vaccine developed by Albert Sabin is approved for use in the U. S. after trials are conducted abroad on more than 100 million people.

1961 Benjamin D. Hall and Sol Speigleman show that singled stranded T2 phage DNA can form a hybrid with RNA from T2 infected Escherichia coli, thus demonstrating the potential of DNA-RNA hybridization methods. Hall, B. D. and S. Speigelman. 1961. Sequence complemetarity of T2-DNA and T2-specific RNA. Proc. Natl. Acad. Sci. USA 47: 137-146. John Holland reports on the correlation between receptors for poliovirus on the surface of cells and the known pathogenicity of the virus for humans and animals. Holland, J. J. 1961. Receptor affinities as major determinants of enterovirus tissue tropisms in humans. Virology 15: 312-326. Francis Crick, Sydney Brenner, and colleagues propose the existence of transfer RNA that uses a three base code and mediates in the synthesis of proteins. Crick, H. F. C., L. Barnett, S. Brenner, and R. J. Watts-Tobin. 1961. General nature of genetic code for proteins. Nature 192: 1227-1232. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.384 [PDF] Marshall Nirenberg and J.H. Matthaei observe that a synthetic polynucleotide, poly U, directs the synthesis of a polypeptide composed only of phenylalanine. They conclude that the triplet UUU must code for phenylalanine. This is the start of successful efforts to decipher the genetic code. With Robert Holley and Har Gobind Khorana, Nirenberg is awarded the Noble Prize in Medicine and Physiology in 1968 1968 Nobel Prize Nirenberg, M. W. and H. J. Matthaei. 1961. The dependence of cell-free protein synthesis in E. coli upon naturally occurring or synthetic polyribonucleotides. Proc. Natl. Acad. Sci. USA 47: 1589. Sydney Brenner, Francois Jacob and Matthew Meselson use phage infected bacteria to show that ribosomes are the site of protein synthesis and confirm the existence of a messenger RNA. They demonstrate infection of Escherichia coli by phage T4 stops cell synthesis of host RNA and leads to T4 specific synthesis. The T4 RNA attaches to cellular ribosomes and directs protein synthesis. Brenner, S., F. Jacob, and M. Meselson. 1961. An unstable intermediate carrying information from genes to ribosomes for protein synthesis. Nature. 190: 576-581. Brian McCarthy and E. T. Bolton describe a method for quantitative determination of the extent of hybridization of DNA or RNA from different biological sources. By this means, it is possible to determine the extent of sequence homology in the genomes of the organisms. Aronson, A. and B. J. McCarthy. 1961. Studies of E. coli ribosomal RNA and its degradation products. Biophys. J. 1: 215-226.

1962 Daniel Nathans, Norton Zinder, and colleagues use E. coli cell-free system together with bacteriophage f2 RNA to produce viral coat protein identical in amino acid sequence to that isolated directly from the virus. With Arber and Smith, Nathans is awarded the Nobel Prize in Medicine and Physiology in 1978 1978 Nobel Prize Nathans, D., G. Notani, J. H. Schwartz, and N. D. Zinder. 1962. Biosynthesis of the coat protein of coliphage f2 by E. coli extracts. Proc. Natl. Acad. Sci. USA 48: 1424-1431. James Gowans determines that small lymphocytes can initiate both cellular and humoral immune responses to specific antigens. They are the units of selection in the Burnet theory of clonal selection. Gowans, J.L., D.D. McGregor, D.M. Cowen, and C.E. Ford. 1962. Initiation of Immune Responses by Small Lymphocytes. Nature 196:651-55 In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.140 [PDF]

1963 Baruch Blumberg describes the "Australia Antigen" (hepatitis B antigen) that is found in the blood of viral hepatitis sufferers. Together with Irving Millman, Blumberg develops a vaccine against the virus. Some consider it to be the first vaccine against cancer because of the strong association of hepatitis B with liver cancer. With Gadjusek, Blumberg is awarded the Nobel Prize in Medicine and Physiology in 1976 1976 Nobel Prize Blumberg, B. S. and N. M. Riddell. 1963. Inherited antigenic differences in human beta lipo-proteins. A second antiserum. J. Clin. Invest. 42: 867-875.

1964 Robin Holliday proposes that genetic recombination in yeast proceeds through two single stranded breaks made simultaneously at the same sites on the two DNA molecules to be recombined. The model appears to work for recombination of all organisms. Holliday, R. 1964. A mechanism for gene conversion in fungi. Gen. Res. 5: 282-304. Charles Yanofsky and coworkers define the relationship between the order of mutatable sites in the gene coding for Escherichia coli tryptophan synthetase and the corresponding amino acid replacements in the enzyme. It worked well for tyrptophan synthetase because the enzyme has two subunits, one of which could b emutated. The missense mutants in the alpha subunt could be mapped and related to the genetic fine strucutre of the gene. The property of correlating a mutation with an amino acid replacement is called colinearity. Yanofsky, C., B.C. Carlton, J.R. Guest, D.R. Helinski, and U. Henning. 1964. On the colinearity of gene structure and protein structure. Proc. Nat’l. Acad. Sci. 51:266-74 In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.392 [PDF] Earl Stadtman and colleagues demonstrate that methyl-B12 is involved in acetate synthesis and is the first step in the acetyl-Coa pathway. J.M. Poston, K. Kuratomi, and E.R. Stadtman. 1964. Methyl-vitamin B12 as a source of methyl groups for the syntesis of acetate by cell-free of Clostridium thermoaceticum. Ann. N.Y. Acad. Sci. 112:804-06. InMicrobiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.210 [PDF]

1965 Sol Speigleman and I. Haruna show that a virally coded replicase from phage Q beta can synthesize infectious viral RNA from precursor nucleotides. This establishes the concept of viral RNA acting as a genome. Spiegelman, S., I. Haruna, I. B. Holland, G. Beaudreau, and D. Mills. 1965. The synthesis of a self-propagating and infectious nucleic acid with a purified enzyme. Proc. Natl. Acad. Sci. USA 54: 919. Ellis Englesberg, J. Irr, J. Power, and N. Lee add to the repertoire of regulatory control mechanisms by showing that an activator protein is required for the expression of the genes determining arabinose metabolism in E. coli. Englesberg, E., J. Irr, J. Power, and N. Lee. 1965. Positive control of enzyme synthesis by gene C in the L-arabinose system. J. Bact. 90: 946-957. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.400 [PDF] The key to the whole field of nucleic acid -based identification of microorganisms was the introduction of the concept of molecular systematics using proteins and nucleic acids by the American Nobel laureate Linus Pauling. Since the sequence of nucleic acids in a particular microorganism is extremely conservative constant, even over geological time, and the DNA and RNA molecules are relatively stable, they are excellent materials for the detection and identification of microorganisms. Zuckerkandl, E., and L. Pauling. "Molecules as Documents of Evolutionary History." Journal of Theoretical Biology 8:357-366

1966 Bruce Ames uses autotrophic strains of Salmonella typhimurium to screen for mutagens and potential carcinogens. The test is based on a determination of whether exposure to a particular chemical alters the mutation rate of the microorganism. There is a high correlation between mutagenicity and carcinogenicity in the "Ames test". Smith, D. E., and B. N. Ames. 1966. Phosphoribosyladenosine monophosphate, an intermediate in histadine biosynthesis. J. Biol. Chem. 240: 3056-3063. Jon Beckwith and Ethan Signer transpose the lac region of E. coli into another microorganism to demonstrate genetic control. The implication of this work is the realization that chromosomes could be redesigned and genes moved. Beckwith, H. R.[sic] and E. T. Signer. 1966. Transposition of the lac region of E. coli. I. Inversion of the lac operon and transduction of the lacoperan by (phi)80. J. Mol. Biol. 19: 254. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.414 [PDF] William Kirby and Alfred Bauer establish standards for antibiotic susceptibility testing based on a single disc diffusion procedure that distinguishes susceptible strains of bacteria from their resistant variants. This method permits clinical laboratories to provide physicians with accurate, reproducible, and reliable information with which to chose antimicrobials. Bauer, A. W., W. M. M. Kirby, J. C. Sherris, and M. Turck. 1966. Antibiotic susceptibility testing by a standardized single disk method. Am. J. Clin. Path. 45: 493-496. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.40 [PDF]

1967 Walter Gilbert and Mark Ptashne isolate the repressor regulatory molecules postulated by Jacob and Monod. Gilbert isolates the lac repressor protein and Ptashne purifies the lamda repressor from bacteriophage. The repressor protein recognizes a specific site on the genome and binds to the site preventing transmission of DNA into RNA. Repressors are a key element of regulatory pathways and affect reaction by genes to environmental signals. Gilbert, W. and B. Muller-Hill. 1966. Isolation of the lac repressor. Proc. natl. Acad. Sci. USA 56: 1891-1898. Ptashne, M. 1967. Isolation of the phage repressor. Proc. Natl. Acad. Sci. USA 57: 306-313. J. Woodland Hastings shows that Vibrio fischeri, a luminous species of bacterium, produces a diffusible compound, termed an autioinducer, which accumulates in the medium during growth. This phenomenon allows the bacterium to sense its elevated density. The concept is analogous to the production of pheromones in higher organisms. Quorum Sensing in Gram Negative Bacteria, ASM News 63, 1997. p.371 [PDF] Hastings, J. W., and Q. H. Gibson. 1967. The role of oxygen in the photoexcited luminescence of bacterial luciferose [Photobacterium fischeri] J. Biol. Chem. 242: 720-726. Waclaw Szybalski and William Summers use the bacteriophage T7 to show that only one DNA strand acts as a template for RNA synthesis. They use the technique of DNA-RNA hybridization to anneal the newly synthesized RNA to a parent DNA strand. Summers, W. C. and W. Szybalski. 1967. Y-Irradiation of deoxyribonucleic acid in dilute solutions: I. A sensitive method for detection of single-strand breaks of polydisperse DNA samples (bacteriophage, Sarcina lutea, Escherichia coli, Bacillus subtilis, Crytophaga johnsoni). J. Mol. Biol. 26: 107-123. Summers, W. C. and W. Szybalski. 1967. Gamma-irradiation of deoxyribonucleic acid in dilute solutions: II. Molecular mechanisms responsible for inactivation of phage, its transfecting DNA, and bacterial transforming activity. J. Mol. Biol. 26: 227-235. Theodor O. Diener discovers viroids, plant viruses that do not have a protein capsid. The infectious agent is a low molecular weight RNA that contains no protein capsid. Among the plants that are affected are potatoes, coconuts, and tomatos. Diener, T. O. 1967. Potato spindle-tuber virus; a plant virus with properties of free nucleic acid. Science 158: 378-381. Thomas Brock identifies the thermophile bacterium Thermus aquaticus from which heat stable DNA polymerase is later isolated and used in the polymerase chain reaction. Brock became interested in microbial mats during a trip to Yellowstone. It was believed at the time that the upper limit for bacterial growth was 73 degrees centigrade. Brock isolated a pink material that was growing at 85 degrees centigrade. Later the bacterium was cultured and ultraviolet irradiation was used to prove growth was taking place. Isolation and culture of this organism later leads to the discovery of the domain Archea. Early Days in Yellowstone Microbiology, ASM News 64, 1998. p.137 [PDF] Brock, T. D. 1967. Micro-organisms adapted to high temperatures. Nature 214; 882-885. Brock, T.D. 1967. Life at high temperatures. Science 158:1012-19.  In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.214 [PDF] R. John Collier describes the mechanism by which diphtheria toxin inhibits protein synthesis in a cell-free system from recticulocytes. This is the first definition at the molecular level of the function of a bacterial protein virulence factor. Collier, R. J. 1967. Effect of diphtheria toxin on protein synthesis: Inactivation of one of the transfer factors. J. Mol. Biol. 25: 83-89. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.146 [PDF] Werner Arber shows that bacterial cells contain highly specific enzymes that add methyl groups to adenosine and cytosine at recognition sites. Methylation is a defensive mechanism of the cell preventing hydrolysis of the parent DNA by nucleases in the cell. These nucleases protect against the introduction of foreign DNA. With Nathans and Smith, Arber is awarded the Nobel Prize in Medicine and Physiology in 1978 1978 Nobel Prize Arber, W. and U. Kehnlein. 1967. Mutational loss of B-specific restriction of the bacteriophage fd. Path. Micro. 30: 946-952. Marvin Bryant, the Wolins, and Ralph Wolfe show that anaerobic bacteria can effect interspecies transfer of H2. One strain oxidizes ethanol to acetate and the other reduces carbon dioxide to methane. This provides an explanation for the interactions of anaerobes during the fermentation of complex organic compounds. M.P. Bryant, E.A. Wolin, M.J. Wolin, and R.S. Wolfe. 1967. Methanobacillus omelianskii, a symbiotic association of two species of bacteria. Archiv. Fur Mikrobiologie 59:20-31. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.224 [PDF]

1968 Lynn Margulis proposes that endosymbiosis has led to the generation of mitochondria and chloroplasts from bacterial progenitors. Margulis, L. 1968. Evolutionary criteria in Thallophytes: A radical alternative. Science 161: 1020-1022. Charles Helmstetter and Stephen Cooper, using the "baby machine" establish the rules for replication in the Escherichia coli cell cycle. Cooper, S. and C. Helmstetter. 1968. Chromosome replication and the division cycle of Escherichia coli B/r. J. Mol. Biol. 31: 519-540 From the Woods Hole Marine Station summer research program came the discovery by Levin and Bang that the lysate of the amebocytes from the hemolymph of the horseshoe crab, Limulus polyphermus clots in the presence of the lipopolysaccharides in the cell walls of gram-negative bacteria. This finding lead to the development of an in vitro assay for the pyrogens that contaminated injectable products that replaced the rabbit pyrogen test. Levin, J., and F. B. Bang. "Clottable Proetin in Limulus: Its Localization and Kinetics of its Coagulation by Endotoxin." Thrombosis et Diathesis Haemorrhagica 19:186 Bacterial Endotoxin Test:

1969 Julius Adler describes chemoreceptors in bacteria, a discovery demonstrating that bacteria can sense and process environmental information. His method involved inserting a tube of chemicals into a solution of bacteria and then counting the number of bacteria that swam to the chemical. Adler, J. 1969. Chemoreceptors in bacteria. Science 166: 1588-1597. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.428 [PDF] Don Brenner and colleagues establish a more reliable basis for the classification of clinical isolates among members of the Enterobacteriaceae. They use nucleic acid reassociation in which denatured DNA labelled DNA fragments of one organism are reacted under annealing conditions with DNA of another organism. Studies on many species have proven the value of DNA-DNA hybridization to define a species. Brenner, D.J., G.R. Fanning, K.E. Johnson, R.V. Citrella, and S. Falkow.1969. Polynucleotide sequence relationships among members of the Enteriobactiaceae. J. Bacteriol. 98:637-50. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.46 [PDF]

1970 Hamilton Smith and Kent W. Wilcox describe the action of restriction enzymes, which are a bacterial defense mechanism, but which quickly become tools for sizing DNA. They report the isolation of an enzyme capable of cleaving a double strand T7 DNA but not native DNA from the source organism, Haemophilus influenzae, or denatured DNA. They conclude that the enzyme has the ability to recognize specific DNA sequences. With Nathans and Arber, Smith is awarded the Nobel Prize in Medicine and Physiology in 1978 1978 Nobel Prize Smith, H. O. and K. W. Wilcox. 1970. A restriction enzyme from Haemophilus influenzae: I. Purification and general properties. J. Mol. Biol. 51: 379-391. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.164 [PDF] Howard Temin and David Baltimore independently discover reverse transcriptase in RNA viruses. The enzyme, reverse transcriptase, uses single stranded RNA as a template to synthesize a single stranded DNA complement . The latter then acts as a template for a complementary DNA chain consistent with general replication mechanisms. This process establishes a pathway for genetic information flow from RNA to DNA. Temin postulated that certain viruses possess an enzyme in their viral coat that facilitates the duplication of viral genes into the DNA of a cell. He called this gene a proviral gene and speculated that the genetic information was conveyed from RNA to DNA by the enzyme of the gene. With Dulbecco, Baltimore and Temin are awarded the Nobel Prize in Medicine and Physiology in 1975 1975 Nobel Prize Baltimore, D. 1970. Viral RNA-dependent DNA polymerase. Nature 226: 1209-1211. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.518 [PDF]  Temin, H. M. and S. Mizutani. 1970. RNA-dependent DNA polymerase in virions of Rous carcinoma virus. Nature 226: 1211-1213. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.522 [PDF]

1972 Joan Mertz and Ronald W. Davis establish that the R1 restriction endonuclease from Escherichia coli cuts DNA at a specific site four to six nucleotides long. The DNA sequence that is cut is complementary to other DNA cut by the same enzyme. This opens the way for cloning. Mertz, J. E. and R. W. Davis. 1972. Cleavage of DNA by R1 restriction endonuclease generates cohesive ends. Proc. Natl. Acad. Sci USA 69: 3370-3374. Paul Berg constructs a recombinant DNA molecule from viral and bacterial DNA. . With Gilbert and Sanger, Berg is awarded the Noble Prize in Chemistry in 1980 1980 Nobel Prize Jackson, D. A., R. H. Symons, and P. Berg. 1972. Biochemical method for inserting new genetic infromationinto DNA of simian virus 40: Circular SV 40 DNA molecules containing lamda phage genes and the galactose operon of Escherichia coli. Proc. Natl. Acad. Sci. 69: 2904-2909. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.528 [PDF]

1973 Stanley Cohen, Annie Chang, Robert Helling, and Herbert Boyer show that if DNA is broken into fragments and combined with plasmid DNA, such recombinant DNA molecules will reproduce if inserted into bacterial cells. They show that plasmids act as vectors for maintaining cloned genes. Boyer was researching restriction enzymes to determine whether they could cut the DNA at certain points. Cohen was isolating plasmids from E. coli. Cohen and Boyer met at a conference in Hawaii and shared their information.The discovery is a major breakthrough for genetic engineering, allowing for such advances as gene cloning and the modification of genes. The discovery also raised fears about accidental production of organisms with unexpected disease potential. Cohen, S. N., A. C. Y. Chang, H. W. Boyer, and R. B. Helling. 1973. Construction of biologically functional bacterial plasmids in vitro. Proc. Natl. Acad. Sci. USA 70: 3240-3244.  In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.178 [PDF] Daniel Nathans, George Khoury, Malcolm Martin use restriction enzymes to cleave SV40 DNA into specific segments and then construct a complete physical map of the virus. Adler, S. P., and D. Nathans. 1973. Studies of SV40 DNA: V. Conversion of circular to linear SV40 DNA by restriction endonuclease from Escherichia coli B. Biochim. Biophys. Acta. 299: 177-188. Khoury, G., M.A. Martin, T.N. Lee, K.J. Dana, and D. Nathans. 1973. A map of simian virus 40 transcription sites expressed in productively infected cells. J. Mol. Biol. 78:377-89. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.536 [PDF] George Laver and Robert Webster demonstrate that the genomes of influenza virus strains responsible for pandemics possess genome fragments acquired by genome segment reassortment from influenza strains circulating in animals. Laver, G. and R.G. Webster. 1973. Studies on the origin of pandemic influenza. III. Evidence implicating duck and equine influenza as possible progenitors of the Hong Kong strain of human influenza, Virology. 51:391-93 Peter Doherty and Rolf Zinkernagl show that the cellular immune system requires that lymphocytes recognize both the virus invader and major histocompatibility antigens in order to kill virus-infected cells. This establishes the principle of simultaneous recognition, of both self and non-self molecules, as the basis of the specificity of the cellular immune system. Doherty and Zinkernagl are awarded the Nobel Prize in Medicine and Physiology in 1996 1996 Nobel Prize Zinkernagel, R. M. and P. C. Doherty. 1973. Cytotoxic thymus-derived lymphocytes in cerebrospinal fluid of mice with lymphocytic choriomeningitis. J. Exp. Med. 138: 1266-1269. Viral Studies Illuminate the Nature of Immunity, ASM News 65, 1999,  p.340

1974 Paul Berg, David Baltimore, Herbert Boyer, Stanley Cohen, Ronald Davis, David Hogness, Richard Roblin, James Watson, Sherman Weissman, and Norton Zinder publish a letter in "Nature, Science, and the Proceedings of the National Academy of Sciences". They recommend that scientists defer from creating microorganisms with novel genes for drug resistance and toxin production, and also defer inserting cancer causing genes from viruses into bacterial host cells. They also suggest that the Federal government set guidelines for the conduct of research and that scientists themselves organize a conference to discuss these issues. This appeared in the letters to Science from Paul Berg et al as: Potential biohazards of recombinant DNA. Science 185: 303. Ralph Wolfe and Charles Taylor describe a novel coenzyme from a methanogen. This is the first of five new coenzymes, two of which are also widely distributed among the procaryotes. C.D. Taylor and R.S. Wolfe. 1974. Structure and methylation of coenzyme M (HSCH2CH2SO3). J. Biol. Chem. 249:4879-85. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.256 [PDF] David Hogness and Michael Grunstein develop colony hybridization, a technique to transfer bacterial colonies to filters, lyse, and fix the DNA. Labeled probes of single stranded DNA, complementary to the fixed DNA, can be applied to determine the identity of the unknown bacterium. Kreigstein, H. J. and D. S. Hogness. 1974. Mechanism of DNA replication in Drosophila chromosomes: Structure and replication forks and evidence for bidirectionality. Proc. Natl. Acad. Sci. USA 71: 131-139. Jeff Schell and Marc Van Montagu discover that a circular strand of DNA (a plasmid) carried by A. tumefaciens transforms plant cells into tumor cells. Van Larabeke, N., Engler, G., Holsters, M., Elcacker, SVD, Zaenen, I., Schilperoort, R.A., and Schell, J. 1974. Large plasmid in Agrobacterium tumefaciens essential for crown gall-inducing ability. Nature 252:169

1975 The Asilomar Conference is convened to discuss possible problems associated with gene cloning. A one-year moratorium, as well as guidelines for cloning research and for genetic engineering, is suggested. This is described in 1975 as: Genetics: Conference sets strict controls to replace moratorium. Science 187: 931-934. Kyung (June) Kwon-Chung describes sexual reproduction in the fungus, Cryptococcus neoformans. Kwon-Chung, K. J. 1975. Filobasidiella, the perfect state of Cryptococcus neoformans. Mycologia 57: 1197-12 C.M. Wei and Bernard Moss, and Aaron Shatkin and colleagues show that messenger RNA contains a specific nucleotide cap at its 5-prime end that affects correct processing during translation. C.M. Wei and B. Moss. 1975. Methylated nucleotides block the 5’-terminus of vaccinia virus mRNA. Proc. Nat’l. Acad. Sci. 72:318-22. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.550 [PDF] Y. Furuichi, M. Morgan, S. Muthukrishnan, and A. Shatkin. 1975. Reovirus messsenger RNA contains a methylated blocked 5’-terminal strucure: m7G(5’)ppp(5’)GmpCp. Proc. Nat’l. Acad. Sci. 72:362-67. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.556 [PDF] Georg Kohler and Cesar Milstein physically fuse mouse lymphocytes with neoplastic mouse plasma cells to yield hybridomas that can produce specific antibodies and can survive indefinitely in tissue culture. This approach offers a limitless supply of monoclonal antibodies. Monoclonal antibodies permit the generation of diagnostic tests that are highly specific and also function as probes to study cell function. With Jerne, Kohler and Milstein are awarded the Nobel Prize in Medicine and Physiology in 1984 1984 Nobel Prize Kohler, G. and C. Milstein. 1975. Continuous cultures of fused cells secreting antibody of predefined specificity. Nature 256: 495-497.

1976 Thomas Cech and Sidney Altman independently show that RNA can serve directly as a catalyst of hydrolytic reaction. Altman investigated RNase P from Escherichia coli and Cech studied the rRNA gene from Tetrahymena thermophilia. They each determined that an RNA component could be separated from protein while retaining catalytic activity. Cech and Altman are awarded the Nobel Prize in Chemistry in 1989 1989 Nobel Prize Altman, S. 1975. Biosynthesis of transfer RNA in Escherichia coli. Cell 4: 21-30. Cech, T. and M. L. Pardue. 1976. Electron microscopy of DNA crosslinked with trimethylpsorlen: Test of the secondary nature of eukaryotic inverted repeat sequences. Proc. Natl. Acad. Sci. USA 73: 2644-2648. J. Michael Bishop and Harold Varmus identify oncogenes from the Rous sarcoma virus that can also be found in the cells of normal animals, including humans. Proto-oncogenes appear to be essential for normal development but can become cancer genes when cellular regulators are damaged or modified. Bishop and Varmus are awarded the Nobel Prize in Medicine and Physiology in 1989 1989 Nobel Prize Stehelin, D., R. V. Guntaka, H. E. Varmus, and J. Michael Bishop. 1976. Purification of DNA complementary to nucleotide sequences required for neoplastic transformation of fibroblasts by avian sarcoma viruses. J. Mol. Biol. 101: 349-365. Stehelin,D. H.E. Varmus, J.M. Bishop, and P. Vogt. 1976. DNA related to the transforming gene(s) of avian sarcoma virus is present in normal avian DNA. Nature 260:170-73. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.562 [PDF] The National Institutes of Health issues guidelines for the conduct of NIH supported research using recombinant DNA technology. The guidelines define physical and biological containment levels for research. Recombinant DNA Research Guidelines, 41 Fed. Reg. 27902, 1976. William Trager and Jim Jensen succeed in cultivating the human malaria parasite Plasmodium falciparum, which allowed its study, in the laboratory, for the first time. Trager, W., Jensen, J. B. 1976. Human malaria parasites in continuous culture. Science 193: 673-5

1977 Carl Woese uses ribosomal RNA analysis to identify a third form of life, the Archea, whose genetic makeup is distinct from but related to both Bacteria and Eucaryea. Woese, C. R. and G. E. Fox. 1977. Phylogenetic structure of the prokaryotic domain: The primary kingdoms. Proc. Natl. Acad. Sci. USA 74: 5088-5090. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.440 [PDF] G.E. Fox, K.R. Pechman, and C.R. Woese. 1977. Comparative cataloging of 16S ribosomal ribonucleic acid: molecular approach to procaryotic systematics. Int. J. Syst. Bacteriol. 27:44-57. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.264 [PDF] Louise Chow and Richard Roberts, and independently Phillip Sharp show that genes are not uninterrupted strands of genes but are interspersed with non-coding segments that do not specify protein structure. Both make the discovery with adenovirus while looking at viral protein synthesis. This finding establishes a fundamental distinction in information processing between procaryotic and eucaryotic organisms. Roberts and Sharp are awarded the Nobel Prize in Medicine and Physiology in 1993 1993 Nobel Prize Chow, L. T., R. E. Gelinas, T. R. Broker and R. J. Roberts. 1977. An amazing sequence arrangement at the 5’ ends of adenovirus 2 messenger RNA. Cell 12: 1-8. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.574 [PDF] S.M. Berget, C. Moore, and P.A. Sharpe. 1977. Spliced segements at the 5’-terminus of adenovirus 2 late mRNA. Proc. Nat’l. Acad. Sci. 74:3171-75. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.568 [PDF] Walter Gilbert and Fred Sanger independently develop methods to determine the exact sequence of DNA. Gilbert uses the technique to determine the sequence of the operon of a bacterial genome. Sanger and colleagues use the technique to determine the sequence of all 5375 nucleotides of the bacteriophage phi-X174, the first complete determination of the genome of an organism. With Berg, Gilbert and Sanger are awarded the Nobel Prize in Chemistry in 1980 1980 Nobel Prize Maxam, A. M. and W. Gilbert. 1977. A new method for sequencing DNA. Proc. Natl. Acad. Sci. USA 74: 560. Sanger, F., G.M. Air, B.G. Barrell, N.L. Brown, A.R. Coulson, J.C. Fiddes, C.A.. Hutchison, P.M. Slocombe, and M. Smith. 1977. Nucleotide sequence of bacteriophage phi X174 DNA. Nature. 165:687-95 Centers for Disease Control researchers Joseph McDade and Charles C. Shepard isolate and identify Legionella pneumophilia as the bacterial pathogen in a newly discovered pulmonary disease. There are now known to be more that 40 species which occur in water settings. McDade, J. E., C. C. Sheperd, D. W. Fraser, T. R. Tsai, M. A. Redus, W. R. Dowdle, and Laboratory Investigation Team. 1977. Legionaire’s disease: Isolation of a bacterium and demonstration of its role in other respiratory disease. N. Engl. J. Med. 297: 1197-1203. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.62 [PDF] Mothers in Old Lyme (CT) describe a high level of illness among children, which is diagnosed as juvenile rheumatoid arthritis. A research group led by Alan Steere finally begins to investigate in 1977 and using an epidemiological approach finds that deer ticks are the vector. Steere, A. C., S. E. Malawista, D. R. Snydman, R. E. Shope, W. A. Andiman, M. R. Ross, and F. M. Steele. 1977. Lyme arthritis: An epidemic of oligoarticular arthritis in children and adults in three Connecticut communities. Arthritis Rheum. 20: 7-17. Eugene Nester, Milton Gordon and Mary-Dell Chilton show that genes on the A. tumefaciens plasmid are transferred into infected plant cells. Chilton, M.-D., M.H. Drummond, D.J. Merlo, Daniela Sciaky, A.L. Montoya, M.P. Gordon and E.W. Nester Stable incorporation of plasmid DNA into higher plant cells: the molecular basis of crown gall tumorigenesis. Cell 11:263-271 Plant Microbiology: Century of Discovery, with Golden Years Ahead,   ASM News 65, 1999, p.358 Holger Jannasch shows that microbial sulfur oxidation is a source of energy for dense animal colonies in the absence of light at deep sea hydrothermal vents. Jannasch and Wirsen use a device for sampling of microbial populations at depths of 6000 meters and then study the population without decompression. H.W. Jannasch and C.O. Wirsen. 1977. Retrieval of concentrated and undecompressed microbial populations from the deep sea. Appl. Environ. Microbiol. 33:642-46. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.280 [PDF] Wirsen, C. O. and H. W. Jannasch. 1978. Physiological and morphological observations on Thiovulum sp. J. Bacteriol. 136: 765-774.

1979 Smallpox (variola) is declared officially eliminated; last natural case seen in Somalia in 1977. Small quantities remain held under tightly controlled conditions in the U.S. and former U.S.S.R. THE ONLY MICROBIAL DISEASE EVER COMPLETELY DEFEATED. Victory Over Variola, ASM News 44, 1978. p. 639 [PDF] Arita, I. 1979. Virological evidence for the success of the smallpox eradication programme. Nature 279: 293-298. Henderson, D.A. 1979. The saga of smallpox eradication: an end and a beginning. Can. J. Pub. Hlth. 70:212-27

1980 The U. S. Supreme Court rules that microorganisms altered in the laboratory can be patented.

1981 Ananda Chakrabarty receives a patent for metabolizing Pseudomonads developed by conjugation that can degrade camphor, octene, salicylate, and naphthalene. United States Patent #425944. Issued March 31, 1981. Helen Whiteley and Ernest Schnepf at the University of Washington clone a Bt toxin gene. Schnepf, H.E., and H. R. Whiteley. Cloning and expression of the Bacillus thuringiensis crystal protein in Escherichia coli. Proc. Nat. Acad. Sci.78:2893-2897

1982 U. S. Pharmaceutical manufacturer Eli Lilly markets the first genetically-engineered human insulin. Stanley Prusiner finds evidence that a class of infectious proteins he call prions cause scrapie, a fatal neurodegenerative disease of sheep. Prusiner is awarded the Nobel Prize in Medicine and Physiology in 1997 1997 Nobel Prize Prusiner, S. B. 1982. Novel proteinaceaous particles cause scrapie. Science 216: 136-144. Karl Stetter isolates hydrothermophilic microbes (Archea) with optimal growth at 105 degrees C, first from shallow marine springs and later from deep sea smokers. Huber, H., M. Thomm, H. Koenig, G. Thies and Stetter, K. O. 1982. Methanococcus thermolithotrophicus, a novel thermophilic methanogen. Arch. Microbiol. 132: 47-50. Willy Burgdorfer and colleagues report successful investigation and treatment of Lyme Disease. They were able to isolate the organism, a treponema-like spirochete, and show antibody formation in patients with clinically diagnosed Lyme disease. Magnarelli, L. A., J. F. Anderson, R. N. Philip, W. Burgdorfer, and E. A. Caspar. 1982. Endemicity of spotted fever group rickettsiae in Connecticut, USA. Am. J. Trop. Med. Hyg. 30: 715-721. W. Burgdorfer, A.G. Barbour, S.F. Hayes, J.L. Benach, E. Grunwaldt, and J.D. Davis. 1982. Lyme disease – a tick borne spirochetosis?. Science. 216:1317-19. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.70 [PDF] Hartmut Michel succeeds in preparing highly ordered crystals of the photosynthetic reaction center from a purple bacterium. Together with Johann Diesendorfer and Robert Huber, Michel elucidates the details of the photosynthetically active components of protein, quinone, and iron. The structural picture agrees with the order of electron transfer steps established by other experiments. Michel, Diesenhofer, and Huber are awarded the Nobel Prize in Chemistry in 1988 1988 Nobel Prize Michel, H. 1982. Characterization and crystal packing of 3-dimensional bacteriorhodopsin crystals. EMBO J. 1: 1267-1272. Deisendorfer, J., H. Michel, and R. Huber. 1985. The structural basis of photosynthetic light reactions in bacteria. Trends Biochem. Sci. 10: 243-248.

1983 Luc Montaigner and Robert Gallo announce their discovery of the immunodeficiency virus (HIV) believed to cause AIDS. Gallo, R. C., P. S. Sarin, E. P. Gelmann, M. Robert-Guroff, E. Richardson, V. S. Ka lyanaraman, D. Mann, G. D. Sidhu, and R. E. Stahl. 1983. Isolation of human T-cell leukemia virus in acquired immune deficiency syndrome (AIDS). Science 220: 865-867. Montaigner, L., J., L. C. Duquet, C. Axler, S. Chamaret, J. Gruest, M. T. Nugeyre, F. Rey, F. Barne-Sinoussi and J. C. Chermann, 1984. A new type of retrovirus isolated from the patients presenting with lymphadenopathy and acquired immune deficiency syndrome: structural and antigenic relatedness with equine infectious anemia virus. Ann. Virol. (Paris) 135: 119-134. L. W. Riley and colleagues describe for the first time the involvement of E. coli O:157 as an infectious diarrhogenic agent. L.W. Riley, R.S. Remis, S.D. Helgerson, H.B. McGee, J.G. Wells, B.R. Davis, R.J. Hebert, E.S. Olcott, L.M. Johnson, N.T. Hargrett, P.A. Blake, and M.L. Cohen. 1983. Hemorrhagic colitis associated with a rare E. coli serotype. N. Engl. J. Med. 308:681-85. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.74 [PDF] Jeff Schell and Marc Van Montagu, Mary-Dell Chilton and colleagues, and scientists at Monsanto introduce genes into plants by using A. tumefaciens plasmid vectors. Zambryski, P., H. Joos, C. Genetello, J. Leemans, M. Van Montagu and J. Schell. Ti plasmid vector for the introduction of DNA into plant cells without the alteration of their normal regeneration capacity. EMBO J 2:2143

1984 Ralph Isberg and Stanley Falkow clone a gene (inv) from Yersinia psuedotuberculosis that confers an invasive phenotype on the non-invasive strain HB101 of E. coli. This is the first demonstration of transfer of such a virulence property by a single gene. Beeder, A. B., and S. Falkow. 1984. Characterization of common virulence plasmids in Yersinia species and their role in the expression of outer membrane proteins. Infect. Immun. 43: 108-114. Barry Marshall demonstrates that isolates from patients with ulcers all contain a bacterium called Campylobacter pylori, later called Helicobacter pylori. Marshall proves that the bacterium is the etiologic agent by swallowing a dose and developing gastritis, the precursor to ulcer disease. The bacterium uses a novel urease to produce ammonia, allowing it to survive at low pH. Warren, J. R., and B. Marshall. 1983. Unidentified curved bacilli on gastric epithelium in active chronic gastritis. Lancet 1: 1273. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.80 [PDF]

1985 Robert Gallo, Dani Bolognesi, Sam Broder, and others show that AZT inhibits the infectivity and cytopathic effects of HIV in vitro. This discovery is a significant advance in slowing the infective cycle of the virus. Mitsuya, H. K. W. Weinhold, S. N. Lehrman, R. C. Gallo, D. Bolognesi, D. W. Barry, and S. Broder. 1985. 3’-Azido-3’deoxythymidine(BWA509U). An agent that inhibits the infectivity and cytopathic effect of human T lymphotropic virus type III/lymphadenopathy-associated virus in vitro. Proc. Natl. Acad. Sci. USA 82: 7096-7100. U. S. Department of Agriculture grants first license to market a genetically-engineered living organism—a virus to vaccinate against a herpetic disease in swine.

1986 Roger Beachy, Rob Fraley and colleagues show that when tobacco plants are transformed with the gene of the coat protein of tobacco mosaic virus, the plants are resistant to the virus. This opened up a new field in which plants are transformed with the coat protein from other viruses or with other viral genes. Abel, P.P., R.S. Nelson, B. De, N. Hoffman, S.G. Rogers, R.T. Fraley, and R.N. Beachy. 1986. Delay of disease development in transgenic plants that express the tobacco mosaic virus coat protein gene. Science 232:738-43

1988 Kary Mullis uses a heat stable enzyme from Thermus aquaticus to establish polymerase chain reaction technology. The DNA polymerase replicates the DNA of interest plus oligonucleotide primers on either side. The primers are allowed to anneal and the reaction repeated to amplify the target DNA many-fold. Mullis is awarded the Nobel Prize in Chemistry in 1993 1993 Nobel Prize Saiki, R. K., D. H. Gelfand, S. Stoffel, S. J. Scharf, R. Higuchi, G. T. Horn, K. B. Mullis and H. A. Erlich. 1988. Primer-directed enzymatic amplification of DNA with a thermostable DNA polymerase. Science 239: 487-491.. Stanley Falkow proposes a molecular version of Koch’s postulates which has applicability to the assessment of whether a gene or its products are required for virulence. Shaw, J. H. and S. Falkow. 1988. Model for invasion of human tissue culture cells by Neisseria gonorrhoeae. Infect. Immun. 56: 1625-1632.

1990 D.A. Relman, J.S. Loutit, T.M. Schmidt, Stanley Falkow, and Lucy Tompkins show that cat scratch fever or bacillary angiomatosis is caused by a bacterium that can’t be cultured. The authors used two molecular techniques, analysis of 16S rRNA and polymerase chain reaction amplification to identify the causative agent. L.W. Relman, J.S. Loutit, T.M. Schmidt, S. Falkow, and L.S. Tompkins. 1990. The agents of bacillary angiomatosis. An approach to the identification of uncultured pathogens. N. Engl. J. Med. 323:1573-80. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.86 [PDF] The Application of Molecular Biology to Medical Bacteriology Yesterday, Today, and Tomorrow, ASM News 65, 199, p317

1992 The entire sequence of 315,000 units of one of the sixteen chromosomes of the yeast S. cerevisiae is identified, representing a major advance toward the sequencing of all the chromosomes of yeast, a eucaryote. Note: This breakthrough comes 6000 years after the first known use of yeast by humans. Oliver, S. G., et al. 1992. The complete DNA sequence of yeast chromosome III. Nature 357: 38.

1993 J. William Schopf demonstrates that cyanobacter-like taxa were extant 3.46 billion years ago, suggesting that oxygen-producing photoautotrophic organisms had already evolved by that time. Schopf, J. W. 1993. Microfossils of the early Archean apex chert: New evidence of the antiquity of life. Science 260: 640-646.

1995 Craig Venter, Hamilton Smith, Claire Fraser, and colleagues at TIGR elucidate the first complete genome sequence of a microorganism - Haemophilus influenza. R. D. Fleischmann, M. D. Adams, O. White, Etal. 1995.Whole-Genome Random Sequencing and Assembly of Haemophilus influenzae Rd.  In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.286 [PDF] Microbial Genomics: in the Beginning, ASM News 65, 1999, p.322 C. J. Peters, V. E. Chizhikov, S. F. Spiropoulou, S. P. Morzunov, and M. C. Monroe report the complete genome of the hantavirus Sin Nobra NMH10, detected in autopsy tissue of a patient who died of hantavius pulmonary syndrome. Morzunov, S. P., A. Feldman, C. F. Spiropoulou, V. A. Semenova, T. G. Kslazek, C. J. Peters, and S. T. Nichol. 1995. A newly recognized virus associated with a fatal case of hantavirus pulmonary syndrome in Louisiana. J. of Virology 69: 1980-1983.

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