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Introduction to plant pathogenic microorganism
Learn Agricultural Microbiology with Braimy – B.Sc. agriculture
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  1. Father of bacteriology & protozoology: Antony Van Leeuwenhoek (1632-1723)
  • New world of microbes was discovered nearly 3 centuries ago by Antony Van Leeuwenhoek in 17th& 18th century.
  • With help of simplest microscope made by him, he discovered different forms of bacteria (small microbes) & named as animalcules collected from different body parts, water etc.
  1. Middle 18th century
  • Linnaeus created new genus vermes also known as chaos
  • Wirsbery described these organisms as infusoria.
  • Linnaeus classified chaos infusoria (1767)
  • F. Muller classified these bacteria as vibrio & monas

  1. 19th century
  • Ehrenberg established new genus Bacterium & found two more genera Spirillum & Spirochete.
  • Golden age of microbiology: (19th& last two decades of 19th)
  • Dominated by Louis Pastures & Robert Kotch
  • Louis Pasture created new theory of spontaneous generation of life.
  • He found from experiment that spoilage of beer was due to appearance of undesired germs in beer i.e. microorganism i.e. disease creating/pathogenic bacteria.
  • He demonstrated by (heated) bottled beer at 500C & 550C temp. & concluded that we could keep away this developing disease by heating
  • He coined such term as pasteurization, which is now in common use in dairy industry.
  • He was first bacteriologist who discovered germ causing disease “chicken cholera” & established new germ theory of immunization against disease.
  • To which bacteria on the process of growth become old and could lose their power of causing disease which helped to produce vaccines from bacilli.
  • Discovery of bacilli was made by German physician Robert Kotch (1843-1910) (19th-20th century)
  • He isolated anthrax in culture and liquid & solid culture media including blood serum and blood agar was used for culture
  • Organism grew in cluster called colonies & become visible by naked eye.
  • New approach in microbiology was made by English surgeon Lord Lister (19th-20thcenturies) by making practical application of bacteriology in the field of medical surgery.
  • Used sterilized appliances and antiseptic dressing preventing bacterial contamination.
  • 1888, Pasteur laid foundation for Pasteur institution, In Paris (A laboratory)
  • Russian scientist/microbiologist working together found that leucocytes eat disease causing bacteria in body & proposed theory of phagocytosis.

  1. Last two decade of 19th century were considered as golden age/years of development of microbiology.
  • Staining of bacteria was used in these years.
  • Methyl violet dye-used first by Weigert(1875).
  • Gram staining technique was widely used now, applied by Gram(1884)
  • Bacteria retaining primary dye after alcohol treatment are gram +ve & others as gram –ve bacteria.
  • In late 19th centuries, Biejernick (1888) isolated & studied the root nodule bacteria & found that they fixed atm. N. in root nodule of legumes.

  1. Last decade of 19th century:
  • Winogradsky, Omeliansky were able to discover those bacteria which fix nitrogen in form of ammonia after successive biological process naming Nitrosomonas, Nitrosococcus, Nitrobacter, and Nitrocystis.
  • In 1892, Ivanowski, Russian botanist, discovered tobacco mosaic virus

  1. Late 19th& 20th century
  • Emil Hansen (1842-1909) opened industrial fermentation by the help of yeast & bacteria.
  • Alexander Fleming(1929)-father of antibiotics
  • Discovered wonder drug-penicillin
  • In further years Streptomycin, polio causing viruses were discovered.
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