Most Probable Number ( MPN ) Counts of Cyanophages
Label the dilution preparation plate using example in guidelines .
Label the sample plates with the date , host , phage name , and any other applicable information ( e . g . the light level ) .
Using a 8x1500 µL multi - channel pipettor , put 270 µL of Pro99 or SN medium in all wells of dilution plate .
Using a 100 µL pipettor , dispense 30 µL of virus sample into row H of the dilution plate .
Repeat this for each of the virus samples .
Using a 12x300 µL multi - channel pipettor set at 30 µL with 12 tips attached , pipette row H up and down to mix the dilution .
Replace the tips and pipette 30 µL from row H into row A ( the 10 - 2 row ) .
Pipette up and down several times to mix .
Replace the tips and transfer 30 µL into row B ( 10 - 3 row ) .
Repeat this mixing , replacing tips and transferring 4 more times until you are at row F ( 10 - 7 row ) .
Using a 12x300 µL multi - channel pipettor set to 30 µL with 8 tips attached , pipet 30 µL host cells into all appropriate wells of the sample plate .
Reset the pipettor to dispense 20 µL , put on 8 fresh tips and transfer 20 µL from the virus dilution plate to the same corresponding column in the sample test plate .
Put the lids on the sample test plates and place in incubator under appropriate light and temperature conditions for each host , and let the virus adsorb to the host for 1 hr .
Using the 8x1500 µL multi - channel pipettor set to step 6x200 µL , add 200 µL of Pro99 or SN medium to all wells in all sample plates .
Seal each plate with parafilm and return plates to the incubator
