Ther do not seem to be any special conditions for plaque formation on FMB agar with nonfermenting indicators. Although pour
plates with a nutrient or tryptone surface layer are preferable, surface spreadings have also been successfully used for rough
It is difficult to suggest strains for the mixture experiments you describe without more details. But for a start, why not
try the follwing: W-1485 as a iambda-sensitive fermenter (Lps Lac+ prototroph) and W-2264 as the lysogenic nonfermenter (Lp
+ Lac4- prototroph) on FMB lactose agar. Certain complications arise with Lac1-4. You already have W-1485, and the series
of Lac- prototrophs (W-2261, W-2262, W-2264, and W-2267) may be obtained from Sol.
If these prove to be unsuitable, let me know, and I will dig up something else from our collection. Best regards from us