Emergence of special fields of Microbiology:

Immunology:

•  Immunization was first used against small pox. Edward Jenner used fluid from cowpox blisters to immunize against it.

•  Pasteur developed techniques to weaken organisms so they would produce immunity without producing disease.

•  Elie Metchnikoff discovered that certain cells in the body would ingest microbes and named them as phagocytes.

 

Industrial Microbiology and Microbial ecology:

•  Pasteur – fermentation technology and pasteurization. One of his most important discoveries was that some fermentative microorganisms were anaerobic and others were able to live either aerobically or anaerobically.

Microbial ecology – Two pioneers –

•  Sergei N. Winogradsky (1856-1953) – Soil microbiology – discovered that soil bacteria could oxidize iron, sulfur and ammonia to obtain energy and many bacteria incorporate CO2 into organic matter. He also isolated anaerobic nitrogen fixing soil bacteria and studied the decomposition of cellulose.

•    Martinus Beijerinck (1851-1931) – He isolated aerobic nitrogen fixing bacterium Azotobacte r, a root nodule bacterium also capable of fixing nitrogen (later renamed as Rhizobium ); and sulfate reducing bacteria. Both of them developed enrichment culture technique and use of selective media, which have been of great importance in microbiology.

Virology:

•  Beijerinck characterized viruses as pathogenic molecules that could take over a host cells mechanisms for their own use

•  Wendell Stanley (1935) – crystallized TMV and crystals consisted of protein and RNA.

•  Viruses were first observed with an EM in 1939.

•  Alfred Hershey and Martha Chase (1952) – demonstrated that the genetic material of some viruses is DNA

•  James Watson and Francis Crick (1953) -determined the structure of DNA