RESUMEN
A subset of food-borne Campylobacter jejuni strains utilizes amino acids asparagine and glutamine as carbon sources that may enhance the ability of this microaerophilic pathogen to colonize specific tissues. In this study, we analyzed the transcript sizes of the ansB and ggt genes encoding the periplasmic asparaginase and γ-glutamyltranspeptidase in C. jejuni 81-176, respectively, and compared the expression level of mRNAs at different time points during the growth in vitro. In addition, we included the housekeeping rpoA gene, encoding the α-subunit of DNA-directed RNA polymerase, to monitor sample processing as it has been described as a stable reference gene in gene expression studies in C. jejuni. Our results revealed that both the ansB and ggt genes were expressed in the end of the logarithmic growth phase and their corresponding monocistronic mRNAs were not affected by sample processing steps. In contrast, the mRNAs of the polycistronic operon containing rpoA gene were highly induced at earlier stage of the logarithmic growth and were clearly differentially responding to external factors during cell harvesting step.