• Temperature, pH, oxygen and available nutrients influence cell growth

• Liquid media gives cells better access to nutrients

Bacterial Transfer

• Pick up bacteria with an inoculating loop

• Start in the 1st quadrant and draw a zig-zag

  • Continue by dragging this to the 2nd quadrant, and repeat for the rest

• You can also continuously streak across the whole plate

Agar Prep

1. Mix agar and water and then heat

2. Wait until it is cooled down to add additives

3. Pour agar when it has cooled down by holding the lid on the petri dish slightly above it (do not set the lid down)

4. Store agar upside down

Koch’s Postulates

• Used to determine the relationship between diseases and pathogens

  • 1st Postulate- Microbe should be in diseased person, but not healthy person

  • 2nd Postulate- Microbe can be cultured from diseased person

  • 3rd Postulate- Microbe from culture will cause disease when put into healthy person

  • 4th Postulate- Microbe can be re-isolated and it will be the same as before

• If something fulfills these 4 postulates, it is the causative agent of the disease

  • Today there are some discrepancies with the original postulate, such as unculturable microorganisms or multiple pathogens causing the same disease

Aseptic Techniques

• Methods of preventing contamination by microorganisms

  • Using gloves

  • Not setting lids down

  • Keeping lid of petri dish over it

  • Use of alcohol or other cleaners

Vocabulary

• Cell culture- process of growing cells in a laboratory

• Agar- solid media

• Broth cultures- liquid media (better access to nutrients)

• Simple media- has only a few nutrients (no special requirements)

• Selective media- has additives that allow only certain cells to grow

• Enriched media- additional growth factors (blood agar)

• Differential media- allows multiple microbes to grow but form individual colonies

• Koch’s postulates-four criteria that are used to to identify the causative agent of a particular disease

• Autoclave- sterilizes things using heat, pressure, & steam

• Lyophilization- Where the water is removed from the thing (ex. dried bacteria)

• Primary cells- Cells taken directly from animals

• Cell lines- Primary cells that are made immortal

• Contact inhibition- Where eukaryotic cells stop growing when they touch each other

• Fermenters- where large-scale cell cultures are grown in suspension broth cultures

• Microbiological tools- inoculating loops & needles

  • Used to transfer cultures

• Serial dilution- diluting petri dish by a known factor (used to count numer of cells)

• Quadrant streak- Inoculating 4 quadrants on petri dish to isolate colonies

  • Drag loop between each quadrant

  • Used to isolate colonies

• T-streak- Same as quadrant streak but only 3 quadrants are used

• Colony forming units- number of cells

• Continuous streak- One zig-zag on petri dish

• Sterilization- to destroy all microbial life + endospores

• Disinfection- to destroy microbial life but NOT endospores

• Antisepsis- use of liquid antimicrobial chemical on skin or living tissue to destroy microorganisms

• Decontamination- process to make something safe to handle

• Cleaning- use of water and detergent to remove materials & reduce number of microorganisms

• Pluripotent stem cells- Can differentiate into any cell in the human body

• Adult stem cells- In tissue/organ and can specialize only to cells in that tissue/organ