Microbiology Notes

Intro to Microbiology

Microbiology

• Study of microorganisms (bacteria, algae, protozoans, fungus, helminthes, virus).
• Microorganisms are too small to see with the naked eye; magnification is required.

Microbes and the Planet

• Two basic cell types:
  • Eukaryotic: nucleus, organelles, bigger.
  • Prokaryotic: no nucleus, no organelles, smaller.
  • Only bacteria are prokaryotic.
• Microbes exist everywhere, even in places where other organisms cannot survive.
• Ecology: bacteria recycle nutrients (decomposers).
• Photosynthesis: some bacteria and protozoans use the sun to make food; oxygen producers.
• Microbes produce gases (CO2, NO, CH3) that regulate Earth's temperature.

Microbes and Humans

• Historical uses: bread, alcohol, cheese, antibiotics.
• Biotechnology: using microbes (bacteria, yeast) in industry (cloning, GMO foods, medicine production).
• Bioremediation: using microbes to clean up the environment (heavy metals, radiation, toxic waste).

Microbes Harming Humans

• Pathogens: microbes that cause disease.
• Emerging diseases: AIDS, Hep. C, Mad Cow, West Nile, Zika, COVID-19, MERS, SARS.
• Drug resistant bacteria: MRSA, TB.
• Super Bugs: H1N1.

History of Microbiology

• Robert Hooke:
  • Discovered the "Cell".
• Anton Van Leeuwenhoek:
  • First to describe microorganisms.
• Miasma Theory: the belief that sick or dying people exude a miasma; if it gets on/in you, you die too.
• Spontaneous Generation: The belief that non-living things can give rise to living things.

Louis Pasteur

• Discovered fermentation.
• Invented pasteurization.
• Proposed the Germ Theory of Disease.
• Invented the Swan-necked flask.
• Vaccine for chicken cholera.
• Vaccine for anthrax.
• Human vaccine for Rabies.

Robert Koch

• Developed Koch’s Postulates.
• Proved the Germ Theory of Disease.
• Invented heat fixed slides.
• Invented the Simple Stain technique.

Other Important Figures

• Joseph Lister: Aseptic Technique in surgery.
• Ignaz Semmelweis: Hand Washing before surgery.

Taxonomy

• Science of categorizing and naming unknown organisms.
• Binomial system uses:
  • Genus (capitalized)
  • Species (lowercase)
• Italicized or underlined.
• Example: Bacillus subtilis, Staphylococcus aureus.

Viruses

• Viruses can infect any cell type.
• Non-living and non-cellular.
• No metabolism of their own, requiring a host cell for replication.
• Not killed by antibiotics.

Microbes and the Planet

• Ecology: Some bacteria recycle nutrients for the planet (decomposers), including nitrate, nitrite, and nitrogen gas (Nitrogen Fixers).
• Photosynthesis: Some bacteria and protozoans can use the sun to make their own food, acting as Oxygen Producers.
• Microbes in the air, soil and water produce gases such as CO2, NO, and CH3 that help regulate the temperature on earth.