NtrX expression is induced under phosphate-replete conditions.

<p>The expression of NtrX in different media was determined by qRT-PCR and Western blot. (A) qRT-PCR to determine the level of <i>ntrX</i> transcripts in <i>C</i>. <i>crescentus</i> wild type grown in M2G and M5G until stationary phase. Data represent the mean ± standard deviation of three independent experiments, each performed by triplicate. The <i>p</i>-value was determined by a two-tailed Student’s t-test (**<i>p</i><0.01). (B) The CC_NtrX_myc strain was grown in M2G or M5G and samples of these cultures were analyzed after 16 h. Also, at this point an aliquot of the M5G culture was taken, 10 mM sodium phosphate was added and it was further incubated for 1 h or 24 h when samples were withdrawn to be analyzed by Western blot. (C) Initial cultures of CC_NtrX_myc were grown overnight in M2G or M5G, and samples were taken at time zero (lane ‘-’), or they were centrifuged and resuspended in fresh M2G or M5G. After an 8 h incubation aliquots of these samples were analyzed by Western blot. Each experiment from (B) and (C) was performed independently three times, and the result of one of these repetitions is shown.