Lecture 1, History of Microbiology

1. Leeuwenhoek and the founding of the science
   • A. Technical achievement-300X lens
   • B. Observations and publications in letters to Royal Society of London
     • He was able to observe and report about microbes he called "animalcules", little animals
     • from his meticulous drawings, today we are able to infer that he observed cyanobacteria, bacterial motility, etc.
2. Dark ages (attributed to Robert Hooke) of Microbiology
3. Spontaneous generation debate
   1. Long debate (biogenesis vs. spontaneous generation) came to a head in the mid-1800s
      1. triggered by the work of John Needham, who observed microorganisms in broth that had been boiled and then stoppered
      2. Spallanzani showed that, if exposure to air was avoided, there was no growth of microorganisms. Spallanzani hypothesized, but could not prove, that germs were getting in from the air.
      3. Pasteur vs. Pouchet
         1. Louis Pasteur (circa 1860) He started out as a chemist studying crystallization. He formed a theory about the fundamental difference between living and non-living as a result of his work with crystals. As a result, he approached the topic of spontaneous generation with a strong bias favoring biogenesis over abiogenesis. This is an example of "real" science, which is much more personal and complex than it is often depicted in textbooks.
         2. Swan necked flasks and sterile solutions
4. ( ASIDE: if you would like to read about this controversy, and the other contributions of Louis Pasteur, in a recent book based on Pasteur's notebooks, I highly recommend The Private Science of Louis Pasteur, by Geison.)
5. Germ theory of disease-first golden age
   • Pasteur and fermentation, silk worm disease
     • Pasteur was asked to solve problems affecting important French industries - wine making in particular. He was able to show that bad wine was the result of bacterial contamination of the yeast fermentations, and was able to prevent the contamination by raising the temperature of the yeast mix before fermentation. This process came to be known as pasteurization, and the rest, of course, is history.
     • Also showed that an important silk worm disease was caused by a protozoan, and this was the genesis of the "germ theory of disease"
   • Lister, phenol, and antisepsis
   • Koch
     • Pure culture techniques, Potato slices and Petri plates
     • Aside: Linnaeus, Binomial nomenclature, and the designation of microbes
       • Strain: descendant of a single colony from a pure culture
       • species: collection of strains with similar characteristics
       • genus: group of species with similar characteristics
     • Koch's postulates
       • a. microorganism must be found in every case of disease, and not in healthy individuals
       • b. suspect microbe must be isolated in pure culture on artificial medium
       • c. introduction of microbe into test host must cause same (or similar) disease
       • d. microbe must be re-isolated from test host, in pure culture.
     • Where we stand today re:Koch's postulates: still very useful, but one shouldn't take them as gospel
       • BJ Marshall and H. pylori
       • HIV and Hantavirus as cautionary tales
6. Treatments and prevention of infectious diseases
   • Pasteur, attenuated bacteria, and rabies vaccines
     • classic experiment of Pasteur's involved infecting a healthy chicken with an old bacterial culture
       • chicken not only lived, but was able to survive a subsequent inoculation with a fresh culture
       • so, Pasteur realized that the chicken was immune to cholera, and he called the old culure "attenuated", and he designated as "vaccination" the process of using the old culture to make the chicken immune.
     • Pasteur REALLY became famous after saving the lives of many rabies-infecting people. Part of the money for establishing the world-famous Institut Pasteur came from donations of those that had been saved
   • Koch's disaster with the tuberculosis "vaccine"

Key Concepts from the first lecture

1. Biogenesis vs. abiogenesis
2. Genus, species, strain
3. Koch's Postulates
4. Famous microbiologist from the past