Figure 5

Manipulating F colonies via the gas phase. a. Cross-septum effects. Colonies are shown 4 days after planting into a compartment of a septum-divided Petri dish containing in its other compartment (i) bacterial (F) suspension; (ii) F- macula previously grown for 3days on a cellulose membrane; (iii) macula-conditioned agar obtained by growing a macula as in (ii), but removing it (with the membrane) immediately before colony planting; (iv) macula-conditioned agar obtained as in (iii), but colonies planted on a virgin agar (i.e. the agar medium in the colony compartment has been exchanged prior to colony plating). Insets: controls grown with uninoculated agar across the septum. b. Cross-septum effects (8 days after planting) of free agar, water, 20% citric acid, or 30% KOH (5 ml each). Bar = 1 cm.