bio⁻

Requires biotin added as a supplement to minimal medium

arg⁻

Requires arginine added as a supplement to minimal medium

met⁻

Requires methionine added as a supplement to minimal medium

lac⁻

Cannot utilize lactose as a carbon source

gal⁻

Cannot utilize galactose as a carbon source

str^r

Resistant to the antibiotic streptomycin

str^s

Sensitive to the antibiotic streptomycin

Note: Minimal medium is the basic synthetic medium for bacterial growth without nutrient supplements.