Question

Given a phage lysate with 5 x 10^10 pfu/ml and a bacterial culture with 10^9 cfu/ml, What dilution of phage lysate would you use to obtain an MOI = 10? (use equal volumes

Answer 1

Given, phage Lysate =5*10^1o pfu(plaque forming colony) / ml [plaque forming colony is the no.of infectious virus particle]

Bacterial culture =10⁹ cfu(colony forming unit) / ml [ie,the no.of viable bacteria]

given MOI(multiplicity of Infection) =10 (it is the average no.of virus particles infecting the cell)

MOI=Plaque forming colony / No.of bacterial Cell(given MOI = 10)

taking equal volume (say 1 ml) there is 5*10¹⁰ pfu & 10⁹ cfu

when x dilution of phage lysate is taken,it contains x*5*10¹⁰ virus

given MOI = 10

ie, x*5*10¹⁰/10⁹ =10

ie, x*50=10

x=10/50=1/5(0.2)

hence ,0.2 dilution of phage lysate can be used to obtain MOI in this case