Historical Highlights Of Microbiology

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Anton Von Leeuwenhoek

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1676-1687 used his self-made microscope to discover bacteria and described them in publications. Used the name "animalcules" to refer to these microorganisms.

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1766-77
Lazzaro Spallanzani

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-disproves the theory of spontaneous generation of microbes in a series of experiments contoured about boiling of "infusions" and sealing the necks of the glass vessels by melting the tips.

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Spallanzani thus carries Francesco Redi's 17th Century disproof of spontaneous generation of maggots down to the micro organismic level. Critics, however, point out that oxygen is excluded from the sealed flasks and that this is the real reason for the failure of microbes to grow.

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Edward Jenner

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1798-develops the technique of vaccination using cowpox virus (which cannot cause a serious human disease) against smallpox virus (which can) Pasteur's discoveries vastly increased the applicability of Jenner's techniques to a broad range of diseases (e.g.. rabies, flu, polio, etc.)

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Mattias Schleiden and Theodor Schwann

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1838-9 publish their CELL Theory; later enhanced by Rudolph Virchow's (1861) publication of his findings that all cells are derived from pre-existing cells (no spontaneous generation)

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Theodor Schwann, Franz Schulze, John Tyndall

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1850's develop methods of "treating" the air that entered unsealed flasks of boiled infusions (methods ranged from sucking air through acid baths, through red-hot glass tubing, through cotton plugs). These experiments also demonstrate that spontaneous generation does not occur. Critics insist, again, that the air has been "damaged" by these treatments.

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Ignaz Phillipp Semmelweis

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1861-pioneers the use of antiseptics (solutions of hypochlorite - similar to Clorox) in the prevention of "childbed fever" in Vienna.

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Louis Pasteur

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1861-64- Finally settles the issue in a series of experiments centered about the use of unsealed unfiltered, untreated-air flasks which have long, convoluted necks which he terms "swan-necked flasks". the spores and bacteria present in the air settle out in the lower portions of the necks, thus failing to reach the infusions.

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Ernst Haeckel

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1866- Proposes a three-kingdom system of classification with all microbes confined to a "protist" kingdom.

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1870's-1880's
Robert Koch

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becomes the first to isolate a disease-causing bacterium and demonstrate that the pure culture's can generate disease in healthy animals. the Organism is Bacillus anthraces, the causative agent of Anthrax.By virtue of his work, Koch becomes known as the "Father of Microbiology" and formulates his famous steps in demonstrating the causative agents of disease, known as "Koch's Postulates"

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Koch's Postulates

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a. a specific organism can always be found in association with a given disease;
b. the organism can be isolated and grown in a pure culture in the lab.
c. the pure culture will produce the disease when inoculated into a susceptible animal
c. it is possible to recover the organism in pure cutler from the experimentally infected animal

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Koch's Lab- 1870's-1880's

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pioneers the use of media solidified by agar (Hesse) and two-piece cutler dishes (Petri). Also developed the first stains that help to reveal the shape and morphology of microorganisms. The stains are derivatives of the coal tar (aniline) dyes whose production in Germany deals a fatal blow to the natural dye industries of the British Empire (especially India)

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1878
Joseph Lister

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becomes the first to produce a "pure culture" (entire culture of microbes derived from a single cell) by serial dilution (Bacillus lactis).

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1884
Hans Gram

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develops the first "differential stain" for use on bacteria, the famous "gram stain" still in use today. Mixtures of bacteria stain differently with the technique- some becoming purple (gram positive) and others becoming pink (gram negative). This technique splits the bacteria into two natural groups.

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1890's
Edwin Klebs, Frederick Loeffler, Emil Von Behring, Shibasuburo Kitasato

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find that diphtheria bacilli (Corynebacterium diphtheria) can produce their toxin in culture and discover that the toxin itself can be used to create immunity to the disease effects.

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1890's
Paul Ehrlich

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develops the first chemotherapeutic agent against disease- organic arsenicals against syphilis

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1890's
Joseph Lister

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pioneers the use of carbolic acid (phenol) as an antiseptic and disinfectant. He is much more successful in promulgating the use of antiseptics than was Semmelweis.

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1892
Dimitrii Ivanowski

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proposes that some diseases, which fail to respond to investigations following Koch's Postulates, might be caused by extremely small, "filterable' agents- so small that they could pass through the pores in ceramic filters. Tobacco mosaic disease was his example and some fifty years later (1935) Wendell Stanley Sr. becomes the first to isolate and crystallize "tobacco mosaic virus".

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1928
Fred Seymour Griffith

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discovers bacterial transformation by foreign DNA (working with Streptococcus pneumonia). Principle not understood until 1944 by Avery, MacLeod and McCarthy. Transformation is on of the key processes used in genetic engineering technology today.

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1930's and 1940's
Hans Krebs, Gustav Embden and Otto Meyerhof

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work out the essential pathways used by organisms in the oxidative breakdown of sugars for energy.

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1946
Joshua Lederberg and Edward Tatum

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discover bacterial conjugation, a pseudo-sexual process whereby bacteria exchange genetic information

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1952
Lederberg and Zinder

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discover the principle of bacterial transduction, whereby bacterial viruses can transfer genetic information from one cell to another during the infective and replicative cycle.

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1953
Watson and Crick

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discern the structure of DNA

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1969
R.H. Whittaker

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proposes the "5-Kingdom System" of classification; this reigned supreme until the work of Carl Woese (3 Domains), in the 1990s

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1977
Sanger, Niklen and Coulson

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develop methods for sequencing DNA, which aids in the development of "genetic engineering" in the 1980's and 90's

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1880
Louis Pasteur

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develops techniques for producing "attenuated" bacteria from the causative agent of chicken cholera. This led the way to producing vaccines against disease from live bacteria which would not kill the patient.