Carmen Michán

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The TOL plasmid upper pathway operon encodes enzymes involved in the catabolism of aromatic hydrocarbons such as toluene and xylenes. The regulator of the gene pathway, the XylR protein, exhibits a very broad effector specificity, being able to recognize as effectors not only pathway substrates but also a wide variety of mono- and disubstituted methyl-,(More)
By multiplex reverse transcription-PCR, we demonstrate that the SoxRS response, which protects cells against superoxide toxicity, is triggered also by hydrogen peroxide. SoxR-dependent inductions of 7. 3-, 7.6-, 4.6-, 2.2-, and 2.6-fold were quantified for soxS, micF, sodA, inaA, and fpr transcripts, respectively. This finding suggests an extensive and(More)
This study reports a genetic analysis of the interactions between a positive regulator of gene expression and its effector molecules. Transcription of the TOL plasmid meta-cleavage pathway operon is specifically stimulated by the XylS protein positive regulator either through activation of this regulator by benzoate effectors or through its hyperproduction.(More)
We report the co-ordinated fine-tune of mRNA molecules that takes place in yeast (Saccharomyces cerevisiae) in response to diverse environmental stimuli. We performed a systematic and refined quantification of the absolute expression patterns of 16 genes coding for thioredoxin- and glutathione-dependent redox system components. Quantifications were(More)
The XylS protein is the positive regulator of the promoter controlling the meta-cleavage pathway (Pm) for catabolism of certain alkylbenzoates on the TOL plasmid of Pseudomonas. Transcription from Pm is mediated by XylS either in the presence of benzoate effectors or through XylS hyperproduction. Two regions of the NH2 terminus of XylS (residues 37-45) had(More)
The XylS protein is the positive regulator of the TOL plasmid-encoded meta-cleavage pathway for the metabolism of alkylbenzoates in Pseudomonas putida. This protein is activated by a variety of benzoate analogues. To elucidate the functional domains of the regulator and their interactions, several fusions of the XylS C-terminus to MS2 polymerase and of the(More)
The Escherichia coli melR gene encodes MelR protein which is a member of the AraC/XylS family of bacterial transcription activators. The function of MelR was investigated by making a targeted deletion in the melR gene of the Escherichia coli chromosome. MelR is a transcription activator essential for melibiose- dependent expression of the melAB operon which(More)
At least twenty-seven proteins belong to the XylS/AraC family of prokaryote transcriptional regulators. All members of this family except CelD and TetD are positive transcriptional factors. Three subgroups were distinguished within the family in accordance with the Needleman and Wunsch algorithm. Multiple alignment of these proteins revealed that they(More)
Simultaneous expression of seven genes in Escherichia coli was measured by a reverse transcription-multiplex PCR fluorescence procedure. Genes studied were (i) oxyR (transcriptional regulator); (ii) katG, dps, gorA, and ahpCF (controlled by OxyR); (iii) sodA (controlled by SoxRS); and (iv) trxA (not related to OxyR or SoxRS). Except for trxA, transcription(More)
We report the absolute transcription profiles of 24 genes coding for putative thioredoxin (Trx)- and glutathione (GSH)-dependent redox system components, accompanying the Candida albicans batch culture growth, under either yeast or hyphal conditions. All mRNAs investigated (plus the housekeeping ACT1) displayed significant alterations in their steady-state(More)