Isolation of Arthrobacter Bacteriophages from a Soil Sample

Take a soil extract containing bacteriophages, including Arthrobacter phages, pre-mixed with a growth medium.

Add Arthrobacter bacteria and incubate under agitation.

Arthrobacter phages attach to the bacterial surface and inject their DNA to produce new phages.

The host cells lyse to release progeny phages, enriching the medium with Arthrobacter phages.

Dilute this medium to reduce the phage concentration.

Add fresh Arthrobacter cells and calcium ions, which aid in phage infection.

Mix with a soft agar and pour onto a nutrient agar plate. The solidifying soft agar immobilizes the bacteria and restricts the phage spread.

Upon incubation, each phage infects a nearby host cell. It then produces progeny phages that infect neighboring bacteria, allowing localized infection.

The uninfected bacterial cells grow, while the infected bacterial cells lyse, detected as clear zones called plaques over a bacterial lawn.

These plaques contain progeny phages, ready for downstream use.

Begin this procedure by adding 1 to 2.5 milliliters of late exponential or early stationary phase bacteria culture to each of the flasks containing filter sterilized LB soil extract mixture. If the OD 600 of the culture is 0.5