Figure 2

Second-round scoring of toxic phenotypes and control. (a) Selected clones from the first round were diluted and three drops (1/100, 1/1,000 and 1/10,000) were spotted and grown for 42 h at 30°C, with controls on same plates, for confirmation of toxicity. Growth levels in the presence and absence of doxycycline were scored as described in the text. Each clone was assigned a growth index where the first number represents the growth in uninduced conditions and second number the growth in induced conditions; for example, 3/3 indicates a non-toxic insert; 3/0 indicates a highly toxic insert. Clone numbers are the same as in the tables describing the toxic inserts (see Additional file 1,2,3,4). (b) After 5-FOA-induced plasmid loss, growth of surviving clones is scored in the same way as in (a). Wild-type phenotypes in overexpression conditions are indicative of plasmid-borne toxicity.