Genetics - Use of Bacteriophage P22 with galE Strains

Jeff Lawrence (G04)

1. Prepare LB-Glu-Gal:
	100 mL 	LB
	0.4 mL	50% Glucose
	1 mL	2% Galactose
2. Grow galE mutants of Salmonella in LB-Glu-Gal prior to lysate preparation. The galE mutation prevents glucose epimerization into galactose. Since galactose is required for the O-antigen attachment of P22, galE strains are P22 resistant. The addition of small amounts of galactose allows O-antigen formation without a toxic buildup of UDP-galactose.

3. Spread 100µL 2% galactose on green plates prior to their use with galE strains.

4. The galE mutation also confer P1 sensitivity to Salmonella typhimurium. However, strains must be grown without galactose to make them P1 sensitive. Strains grown with galactose, or with a wild-type galE gene, are P1-resistant.
Last Update: Thursday June 19 2014
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