Difference between revisions of "PhiX:Serial dilution"
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'''Stock Solution'''<br> | '''Stock Solution'''<br> | ||
The stock solution has a titer = x PFU/ml (PFU = plaque forming units)<br> | The stock solution has a titer = x PFU/ml (PFU = plaque forming units)<br> | ||
− | Alternatively = y | + | Alternatively = y PFU in z ul<br> |
− | ''' | + | '''Serial Dilution Procedure'''<br> |
− | Add 100ul (10<sup>-1</sup>x) phage to 900ul HFB and mix -> tube #1<br> | + | Prepare a set of labelled tubes from #1 to #8. Fill each tube with 900ul of HFB (or PBS will suffice).<br> |
+ | Add 100ul (10<sup>-1</sup>x) stock phage to 900ul HFB and mix -> tube #1<br> | ||
Transfer 100ul (10<sup>-2</sup>x) #1 to 900ul HFB and mix -> tube #2<br> | Transfer 100ul (10<sup>-2</sup>x) #1 to 900ul HFB and mix -> tube #2<br> | ||
Transfer 100ul (10<sup>-3</sup>x) #2 to 900ul HFB and mix -> tube #3<br> | Transfer 100ul (10<sup>-3</sup>x) #2 to 900ul HFB and mix -> tube #3<br> | ||
− | and so on... | + | and so on...Do not forget to change tips and mix between transfers. <br> |
− | |||
− | ''' | + | '''Plating'''<br> |
Tube #1 -> plate 100ul (1/10) -> 10<sup>-2</sup>x<br> | Tube #1 -> plate 100ul (1/10) -> 10<sup>-2</sup>x<br> | ||
Tube #2 -> plate 100ul (1/10) -> 10<sup>-3</sup>x<br> | Tube #2 -> plate 100ul (1/10) -> 10<sup>-3</sup>x<br> |
Revision as of 06:03, 20 February 2017
Summary
This protocol describes how to prepare serial dilutions in order to enumerate phage from a stock solution. Before you begin you should also prepare for the double agar overlay plaque assay onto which fresh dilutions should be plated.
Stock Solution
The stock solution has a titer = x PFU/ml (PFU = plaque forming units)
Alternatively = y PFU in z ul
Serial Dilution Procedure
Prepare a set of labelled tubes from #1 to #8. Fill each tube with 900ul of HFB (or PBS will suffice).
Add 100ul (10-1x) stock phage to 900ul HFB and mix -> tube #1
Transfer 100ul (10-2x) #1 to 900ul HFB and mix -> tube #2
Transfer 100ul (10-3x) #2 to 900ul HFB and mix -> tube #3
and so on...Do not forget to change tips and mix between transfers.
Plating
Tube #1 -> plate 100ul (1/10) -> 10-2x
Tube #2 -> plate 100ul (1/10) -> 10-3x
Tube #3 -> plate 100ul (1/10) -> 10-4x
and so on...
MATHS
E.g. count n plaques on plate from 10-7x plate:
x = n * 10-7
OR, if z = 200ul (e.g., mutagenesis)
y = (n * 10-7) * 200/1000