The pour plate differs from the streak plate in that the agar medium is inoculated while it is still liquid , but cooled to 45 degrees Celsius, and colonies develop throughout the medium, not just on the _____.
The idea is to make successive _____ of the cells and then on at least one of the poured plate colonies will be separated well enough to see them as isolated.
Move quickly; because..
If the medium ____ in the tube, remelting kills the organisms and re inoculation is required.
pour, spread, quadrant streak
Name the three ways to isolate colonies.
1) _____ plate
2) ____ plate
3) ____ ____
Pour Plate Advantages:
- Less ____ than streak methods
- May provide greater _____
reculturing, concentration, seen
Pour Plate Disadvantages:
1) most colonies grow below surface;
- difficult to access for _____
2) surface growth appears different than subsurface growth
3) difficult to get the right ______ of cells/plate for counting (30-300)
-Which means do multiple plates (different concentrations)
4) species with low numbers of colonies may not be _____
Work in groups of 2-3 to complete the procedure
Very important to follow directions and work _____
- Read protocol carefully
- Do not write directly on bottles
*label w/ tape & remove when done
- Prepare everything ahead of time
* Label everything and put inoculum in ____ before getting agar out of the water bath
- Wipe water and condensation off of agar tubes (even under lid), then ___ tube rim before pouring
* Make sure there is nothing growing in the tube
- Swirl gently to mix; leave on bench until solid
- Incubate 37°C
multiples, bench top
Pipets should NEVER:
1) Be removed in _____
2) Placed on a ____ ____ before or after use
A measure of viable cells in which a colony represents an aggregate of cells derived from a single progenitor cell.
- CFU is an ____ measurement
- Correlation of number of colonies to the number of bacteria in _____ culture
average, 30, 300
Count colonies on each of duplicate plates and _____
-choose dilution w/ ___-____ colonies
Quebec colony counter
If too many colonies to easily count, use ____ ____ ___;
-Petri plate is 56cm2
-count 4 squares (1cm2)
-average the counts from 4 squares
-multiply by 56 to get total for plate (56 cm2)
-Take colony count X _____ of dilution factor for the plate that was counted
Ex. 238 colonies counted from plate with 1 ml of 10-8
The measure of the amount of light absorbed by a suspension of bacterial cells or a solution of an organic molecule with the use of a colorimeter or spectrophotometer.
The streak plate method involves streaking the culture across a sterile agar gel surface. In the pour plate method, agar in a molten state is poured over the sample, and the plate is then inverted. The streak plate therefore produces only _____ colonies, whereas the poured plate shows those colonies AND _____colonies both on and within the agar layer.