Contributions to Microbiology
- Antonie Van Leeuwenhoek
- Father of Microbiology
- First one to observe living cells under microscope – 1673
- Discovered Infusoria (protist) – 1674
- Discovered Selenomonads in mouth – 1676
- Discovered spermatozoa
- Sacharis Jansen
- Discovered compound microscope
- Louis Pasteur
- Gave the ‘Germ theory of Disease’
- Gave the ‘Law of biogenesis’
- Disproved Spontaneous generation theory
- Developed Pasteurization
- Developed vaccines for Rabies, Diphtheria and Anthrax
- Opposed Darwinism
- Showed lactic acid fermentation by microbes
- Developed attenuation (heat killing of microbes) to produce vaccines
- Robert Koch
- Father of Bacteriology
- Isolated Bacillus anthracis, Vibrio cholera, Mycobacterium tuberculosis
- Supported ‘Germ theory of Disease’
- Gave Koch’s postulate using B.anthracis as his test organism
- Cultured bacteria on gelatin
- Charles Chamberland
- Invented autoclave
- Invented bacteria proof filter- Chamberland filter
- Emil Adolf Von Behring
- Invented Diphtheria toxoid (weakened form of the toxin)
- Pierre Paul Emile Roux
- Worked in Pasteur Institute in Paris
- Developed anti-diphtheria serum
- Sergei Winogradsky
- Father of Soil Microbiology
- Studied S and N utilizing bacteria
- Isolated anaerobic nitrogen fixing bacteria
- Studied decomposition of cellulose
- Martinus Beijerinck
- Isolated Azotobacter – aerobic nitrogen fixing, free-living bacterium; Rhizobium – symbiotic nitrogen fixer; sulfate reducing bacteria
Conflict Over Spontaneous Generation
According to the famous notion of Spontaneous generation, in earlier times, people believed that living organisms arose from non-living objects. This concept was challenged by an Italian physician, Francesco Redi. Redi placed meat in three containers – one uncovered, second one covered with paper and the third container was covered with a wire gauze. Flies laid eggs on the exposed meat and maggots were formed. The other meats in the two containers did not produce maggots spontaneously. However, flies were attracted to the one covered with the gauze and laid eggs on the gauze, producing maggots. Thus, the maggots arose, as a result of the eggs and not by the meat pieces directly. John Needham, a firm believer of spontaneous generation, boiled mutton broth followed by tight stoppering of the flasks. Eventually many of the flasks turned cloudy and had microbes. He concluded that organic matter contained a vital force that could confer life to inanimate matter. Lazzaro Spallanzani, improved Needham’s experiment by first sealing glass flasks containing water and seeds. If the sealed flasks were kept in heat for ¾ of an hour, no growth occurred in them only as long as they were sealed. He deciphered that air carried germs but external air might also be needed for the growth of organisms already in the culture medium. Theodore Schwann was however, against spontaneous generation. Louis Pasteur attempted to settle this matter once and for all. He first filtered air through cotton and if that cotton was placed in a culture medium, growth was observed. He then placed nutrient broth in flasks, heated their necks and drew them into a variety of shapes but kept their mouth open. Pasteur boiled the solutions for a few minutes and allowed them to cool. No growth occurred. He pointed out to the fact that dust and germs in air, were trapped on the walls of the curved necks. If the necks were broken, growth commenced immediately.
Notes To Remember
- Golden Age of microbiology – 1857-1914
- Leeuwenhoek – Saw microbes first (called animacules), although Robert Hooke drew microbes first
- Ferdinand Cohn – Discovered endospores
- Kary Mullis – Invented PCR
- V.cholerae – has 2 chromosomes
- Jansen – Discovered compound microscope
- John Semmelweis – Introduced the concept of antisepsis
- Joseph Lister – Introduced antiseptic surgery
- Elie Metchnikoff – Discovered phagocytosis
- Laveran – Discovered Plasmodium
- Pasteur – Developed rabies vaccine
- Escherich- Discovered E.coli
- Kitasato & Yersin – Discovered Yersinia pestis
- Bordet – Discovered complement system
- Walter Reed – Proved yellow fever is transmitted by mosquito
- D’Herelle & Twort – Discovered bacteriophages
- Wright – Discovered antibodies
- Ruska – Invented electron microscope
- Jacob & Wollman – Discovered F-plasmid
- Arber & Smith – Discovered restriction endonuclease
- Pasteur & Chamberland – Discovered anthrax vaccine
- Fannie Hesse – Discovered agar could be used as a growth medium
- Richard Petri – Invented petri plates