Figure 1.

The velocity of Pi uptake as a function of substrate concentration. ³³Pi uptake of the wild-type strain CC125 was performed as described in Methods. Cultures in the early logarithmic phase of growth were either transferred to TAP (+P, •) or TA (−P, ○) medium and allowed to continue growth for 24 h before measuring Pi uptake. The insets are double-reciprocal plots of the data, and the K_m values estimated from these plots are 0.16 μm for the high-affinity component and 10 μm for the low-affinity component. chl, Chlorophyll.