Practical procedures Flashcards
1
Q
Serial dilutions
A
- Label universal bottles with 9ml PBS, 10-6 and 10-7 with name, date, organism and bench number
- Use a P1000 pipette to dispense 1ml of 10-5 e.coli into 10-6
- Replace lid and shake
- Transfer 1ml of this to 10-7
- Replace lid and shake
2
Q
Spread plate
A
- Label agar plates 10-6 and 10-7
- Use pipette to dispose 100µl of 10-6 dilution of e.coli onto agar
- Remove sterile spreader and touching only the handle, spread the bacterial culture over the agar surface
- Leave petri dish inverted so condensation will not spill down onto agar surface
- Repeat and incubate at 37 degrees
3
Q
Streak plate culture
A
- Label agar plate
- Flame inoculating loop and cool
- Dip into a single colony on supplied plate
- Zig zag over a small area and flame loop and cool
- 4 straight lines from zig zag, flame and cool
- Repeat until 3/5 plate is covered
- Create a final zig zag over untouched areas and leave agar plate inverted
4
Q
CFU calculation
A
Number of CFU’s x dilution with a positive power / the amount plated (0.1)
OR
Number of CFU’s / dilution x amount plater (0.1)
5
Q
Stock solution
A
- Weigh out solid using a weighing boat
- Transfer to a beaker and dissolve using water
- Transfer to a volumetric flask rinsing the beaker and funnel
- Make volume up to meniscuse line and invert 3 times
