Full text loading...
K+-uptake genes of Vibrio alginolyticus were identified by cloning chromosomal DNA fragments of this organism into plasmids, followed by electroporation and selection for growth at low K+ concentrations of cells of an Escherichia coli strain defective in K+ uptake. A 4.1 kb DNA fragment contained a cluster of three ORFs on the same DNA strand: the previously identified trkA gene, a gene similar to E. coli trkH (V. alginolyticus trkH) and a new gene, orf1, whose function is not clear. Products of V. alginolyticus trkA and orf1 were detected in E. coli minicells. trkA and trkH from V. alginolyticus restored growth at low K+ concentrations of an E. coli ΔtrkA and an E. coli ΔtrkG ΔtrkH strain, respectively, suggesting that these V. alginolyticus genes can functionally replace their E. coli counterparts. In addition, a plasmid containing V. alginolyticus trkAH permitted growth of an E. coli ΔsapABCDF (ΔtrkE) strain at low K+ concentrations. This effect was mainly due to V. alginolyticus trkH and was enhanced by trkA from this organism. Measurements of net K+-uptake rates indicated that the presence of these genes in E. coli renders the Trk systems independent of products from the E. coli sapABCDF (trkE) operon.
Article metrics loading...
Full text loading...
References
Data & Media loading...