Figure 3.

Characterization of growth on eDNA as a phosphorus source. (A) Growth on eDNA as a P source is concentration dependent. H. volcanii DS2 cultures in minimal medium lacking a phosphorus source were provided with unmethylated E. coli DNA at final concentrations of 50, 100, 150, 200, and 250 μg/ml (gray squares, increasing darkness). (B) Optical density achieved after 5 days of incubation at increasing DNA concentrations. (C) Growth on eDNA after 48 h during anaerobic nitrate respiration. H. volcanii DS2 cultures in minimal medium lacking a phosphorus source were prepared and grown under anaerobic conditions with unmethylated E. coli DNA at a final concentration of 200 μg/ml. All cultures other than the no nitrate eDNA control contained 50 mM sodium nitrate. Errors bars represent standard deviation of replicates.