Main sol. 257

Bottom layer: Dissolve 12.0 g Bacto agar in 900 ml distilled water and autoclave. After cooling to 60°C add 100 ml of sterile YP medium (autoclaved at 121°C for 15 min) and pour plates. Dry plates at room temperature for 2 - 3 days .

Top layer: Grow prey bacterium on agar slants using medium 54. Prepare 5 ml aliquots of 0.6% Bacto agar in distilled water and autoclave in test tubes. After cooling to 45°C in a water bath add 0.5 ml sterile YP medium (autoclaved at 121°C for 15 min) and 0.5 ml cell suspension of host organism, mix and pour top layer. For the top layer of one plate use one 24 h old agar slant culture and wash off grown cells in 0.5 ml sterile water.