TABLE 2.

Influence of BCAA, GTP, and glucose and CodY on BsrF transcriptiona

Mediumβ-Galactosidase activity (Miller units)
DB104::pACG6DB104::pACG6(ΔcodY::spc)
CSE305 ± 8308 ± 5
CSE + BCAA606 ± 16318 ± 30
CSE + Glc303 ± 21310 ± 25
CSE + Glc + BCAA909 ± 7301 ± 33
CSE + Glc + isoleucine744 ± 10305 ± 24
CSE + Glc + leucine445 ± 12310 ± 15
CSE + Glc + valine436 ± 15301 ± 12
CSE + Glc +/− GTP324 ± 22/312 ± 30304 ± 10/310 ± 16
CSE + Glc + BCAA +/− GTP903 ± 50/639 ± 27308 ± 21/306 ± 27
CSE + Glc +/− methanol316 ± 15/321 ± 22ND
CSE + Glc + BCAA +/− methanol896 ± 43/907 ± 59ND
  • a All values are averages of at least three independent determinations with five different integrants obtained from cultures grown until the OD600 was 0.3 (logarithmic growth phase). The influence of GTP was measured 30 min after addition of mycophenolic acid (a guanine nucleotide synthesis inhibitor) dissolved in methanol (final concentration, 100 μM) or methanol alone to cultures. The concentration of each BCAA (isoleucine, leucine, and valine) added was 10 mM, and the concentration of glucose (Glc) was 0.1 %. ND, not determined. In cases where no glucose was added, the carbon sources in the CSE medium were succinate and glutamate.