Fig 3.

Effect of copper on development. (A) M. xanthus DK1622 cells were grown in the absence of copper and concentrated to an OD₆₀₀ of 15. Ten microliters of cells was spotted onto CF agar plates containing the indicated copper concentrations. Aggregation was monitored by taking pictures under a dissecting microscope. (B) To quantify the number of spores, cells were concentrated as indicated in panel A. Ten drops of 20 μl each were then spotted onto CF agar plates containing the indicated copper concentrations. After incubation for 72 h, fruiting bodies were harvested from the plates and disrupted by sonication, and spores were quantified in a Petroff-Hausser chamber. Experiments were performed in triplicate. Error bars indicate standard deviations.