Pathogens

• Virus

  • Hepatitis, SARS, Herpes, Mono, AIDS

• Bacteria

  • Tuberculosis, pneumonia, anthrax, urinary tract

• Fungi

  • Ringworm, yeast infection

• Protozoa

• Parasites

The earliest humans used microorganisms for…

• Preservation - but happened mysteriously for some time

• Neolithic human societies did it to make beer and wine through fermentation

  • 7000-6600 BCE in China

  • 6000 BCE in Georgia

  • 3150 BE in ancient Egypt

  • 2000 BCE in pre-Hispanic Mexico

Seeing is believing

• Robert hooke

  • Saw the first cells and coined the term cell when he noticed that cork tree bark looked like monk’s chambers

  • Published Micrographia, spurring a new interest in the microscopic world

• Anton Van Leeuwenhoek (1674-1676)

  • Known as the founder of microbiology as he discovered microorganisms and improved the microscope

  • Made glass lenses and coined the term animalcules

  • Methods kept private, but he shared his accurate drawings and aroused interest in microbiology and challenges the theory of Abiogenesis

    • Corresponded with a scientific institution

    • Abiogenesis: spontaneous generation

      • The thinking was that they don’t know how microorganisms came about, but we know that they do

      • Therefore, they came up with something like observing that bees were burrowed in the rotted flesh of dead animals, making them think that that’s how you make bees

      • Started with Socrates as he believed life could be born spontaneously from dead things

        • Aristotle continued this saying insects grew in mud or dung (thought that all living things came from things like this)

  • Looked at protists, pond water, and sperm (was seen as weird and wished he hadn’t seen it)

• Francesco Redi -1665

  • First scientist who documented that he challenged Abiogenesis

  • Used flies and flesh

    • Demonstrated spontaneous generation did not occur at the macroscopic level

    • But other scientists said no

  • John Needham - 1749

    • Boiled and stoppered flasks but later found the flasks to be teeming with microorganisms

    • Told him spontaneous generation was true

  • Lazzaro Spallanzani -1766

    • Repeated Needham’s experiments, but boiled the flasks longer than the vital force

    • Proved spontaneous generation did not occur

• Theodor Schwan and Franz Schultz (1830s - Germany)

  • Boiled broth and exposed the flasks to open air - no microorganisms were found

  • Schwann agreed with others’ proposition that products of fermentation were created by microorganisms

  • Schwann also said that all animals were made of cells

  • Test to prove Abiogenesis is wrong

    • He lets air into broth and shows that there were no microorganisms (before we knew that microorganisms could travel in air)

    • Louis Pasteur came up with a better method

      • Used a glass with a curved arm, allowing water to condense in the arm of flask and seal it

      • Won the prize from Paris Academy of Sciences for ending Abiogenesis

      • Known as the founder of bacteriology

        • Fermentation was caused by desirable ones

        • Perfected the boiling method for preservation of dairy products

      • Pasteurization

      • Supporter of germy theory of disease

        • Experiments showed bacteria can cause disease and grow in tissues

• Jakob Mathias Schleiden (1830s - Sweden)

  • Said that all plants are made of cells

• Rudolf Virchow (1850s)

  • Founder of cellular pathology

  • Said that new cells arise from pre-existing cells

  • His experiments were accepted because the scientists thought he was right, but we believe that he plagiarized Jewish scientist Robert Remak

Edward Jenner (1749-1823)

• Discovered a safe and efficient vaccination against smallpox

• Known as the founder of immunology

  • Led to the eradication of smallpox when he noticed that dairy workers exposed to cowpox never got smallpox

  • Proved that experimentally that resistance to smallpox can be induced by injecting material from diseases pustules into humans

John Snow (1853-1854, London)

• English physician considered the founder of epidemiology

  • The study of epidemics and how they affect a community

• Cholera outbreaks were a major issue

  • Bacterial disease manifested by diarrhea, which was so severe that life threatening amounts of water are lost from the body

• Identified the broad street pump as the contaminated source of water