Working with Pipettes

  • Pipette Models Used
    • Eppendorf pipettes: p1000 and p100.

Experiment Protocol

Step 1: Pipetting from Tube 2

  • Volume to Pipette: 0.1 mL (100 μL)

  • Method:

    • Pipette a straight line along a radius on plate A.
    • Use a bacteria spreader to cover the surface of the agar with the pipetted bacteria immediately after pipetting.
    • Make sure the radius does not sit on the plate for an extended period before spreading.

  • Sterilization of Equipment:

    • The bacteria spreader must be sterilized and cooled down before use to maintain sterility.

  • Technique:

    • Rotate the plate with your non-dominant hand while using your dominant hand to spread the bacteria.

  • Repeat:

    • Perform the same procedure for plate A2 after sterilizing the bacteria spreader again.

Step 2: Pipetting from Tube 3

  • Volume to Pipette: 0.1 mL (100 μL)

  • Method:

    • Pipette a straight line along a radius on plate B1.
    • Another 0.1 mL is placed along a radius on plate B2.

  • Sterilization of Equipment:

    • After use, sterilize the bacteria spreader before proceeding to the next plate.

  • Technique:

    • Similar to Step 1, rotate the plate with your non-dominant hand while utilizing the dominant hand for spreading.

Step 3: Pipetting from Tube 4

  • Volume to Pipette: 0.1 mL (100 μL)

  • Method:

    • Pipette a straight line along a radius on plate C1.
    • Another 0.1 mL is placed along a radius on plate C2.

  • Sterilization of Equipment:

    • Ensure the bacteria spreader is sterilized and cooled down before use.

  • Technique:

    • The same technique with rotation as previously described for plates A and B.

Important Considerations

  • Timing: Ensure the radius of bacteria does not sit for too long before spreading to prevent any unwanted bacteria growth or contamination.
  • Sterilization: Consistently sterilize equipment before each use to ensure accurate results and prevent cross-contamination.
  • Technique Consistency: Maintain a steady hand and technique while pipetting and spreading to achieve uniform distribution of bacteria across the plates.