Working with phage( T4 bacteriaphage) - several questions abt phage (May/18/2006 )
hi, please let me straight to my questions
1. Why were the phage diluted before they were used to infect the bacteria rather than after they infected the bacteria?
2. What would be the disadvantage of growing a lawn of bacteria, then spreading phage onto it to produce plaques?
Are you trying to do a plaque assay with the phage? If so, you are supposed to grow a lawn of bacteria first, then spread the phage onto it. The phage is dilluted so that you don't end up forming one solid plaque because they are too concentrated. If you dilute it enough, you can see each individual plaque where a phage landed. The number of plaques gives you a rough estimate of how many phages were in the sample.
Here is a passage from a book that may explain it better that I:
"The number of bacteriophages in a sample is assesed by spreading the sample out over a lawn of solid bacterial growth. When the phages replicate and destrooy the bacterial cells, they leave a clear spot, called a plaque, in the lawn. The number of plaques corresponds roughly to the nomber of phages that were initially present in the sample."
-PhageMaster
Here is a passage from a book that may explain it better that I:
"The number of bacteriophages in a sample is assesed by spreading the sample out over a lawn of solid bacterial growth. When the phages replicate and destrooy the bacterial cells, they leave a clear spot, called a plaque, in the lawn. The number of plaques corresponds roughly to the nomber of phages that were initially present in the sample."
-PhageMaster
hmm, your words make some sense and perhaps it was right afterall. I thank you very much for this.
By the way, is it we assume that 1 plaque = 1 phage when we count the phage colony ?
Yes, I believe if the phage preparation is diluted properly, one plaque usually corespondes to one phage.
-PhageMaster