T4 Bacteriophage

Plaque Forming Unit (PFU)

A single infectious virus particle that creates a visible area of clearing on a bacterial lawn

Purpose of 0.5% agar overlay

Soft agar that allows viruses to diffuse/move to neighboring cells while keeping the bacteria immobilized

Lytic cycle

The process where phages infect, replicate within, and burst the host bacteria, creating clear spots called plaques

Bacterial lawn

A solid, uniform layer of bacterial growth on an agar plate

Titer calculation formula

(PFU/volume used in ml)×Dilution Factor

Dilution Factor

The reciprocal of the total dilution

Total dilution calculation

The product of individual dilutions from the first tube to the tube being used

Required 15-minute incubation purpose

Allows time for the bacteriophages to adsorb (attach) to the surface of the E. coli cells

T4 bacteriophage host specificity

Only infects specific strains of E. coli; it is not capable of infecting human cells or the GI tract if ingested