Identification and characterization of a cryptic D-serine deaminase (DSD) gene from Burkholderia cepacia

Isolates of Burkholderia cepacia differed in their ability to utilize D-serine as a carbon and energy source. Strain 17616 is one of the strains which ordinarily fails to utilize D-serine. D-serine also inhibited the growth of this strain on alternative carbon sources such as mannitol. D-serine resistant (Dsd;Efforts were made to define the mechanism of activation of the cryptic dsd gene in strain 17616. Comparison of PCR products of the region upstream of the dsd gene in the wild type and Dsd;Analysis the region downstream of the dsd gene revealed the presence of a marR-like repressor gene and adjacent multi-drug resistance transporter gene. The orientation of the latter two genes was opposite to that of the dsd gene. We were interested in the possibility that the marR (multiple antibiotic resistance/multiple adaptive response) protein might control dsd gene expression. To explore this possibility, I compared the nucleotide sequences of the marR gene from the representative Dsd...