Figure 2

Effects of lrp null mutation on growth rates. Growth rates were determined from a fit to the exponential portion of the growth curve, extending in all but one case (P. mirabilis, glucose minimal medium) through at least four mass doublings. Open symbols refer to growth in MOPS glucose plus required supplements (nicotinate, panthothenate and thiamine; see Methods), while closed symbols represent growth in MOPS glucose defined-rich medium. A. lrp vs. lrp⁺growth rates. The values shown are the specific growth rate constants, k, calculated as ln2/(doubling time, in h). For comparison, k values of 0.5, 1, and 2 correspond respectively to doubling times of 83, 42, and 21 min. The rich medium results are clustered and therefore not labeled; for the minimal medium, the abbreviations used are Eco (E. coli), Pmi (P. mirabilis), and Vch (Vibrio cholerae). The diagonal line shows where points should fall if lrp mutation has no effect on the growth rate in these media. B. Complementation of the low P. mirabilis growth rate in the glucose minimal medium described in (A). The dashed lines indicate growth data for the P. mirabilis lrp mutant (open circles; 193 min doubling time) and the mutant bearing the vector control (gray circles; 191 min). Remaining lines show the WT P. mirabilis (closed circles; 66 min); and the lrp mutant bearing plasmids with the lrp⁺ genes from P. mirabilis (triangles; 69 min), V. cholerae (squares; 81 min), or E. coli (diamonds; 81 min).