Transfer of the Gene Encoding the NapA Acid Phosphatase ofMorganella morganii to aBurkholderia cepacia Strain

Abstract

A composite plasmid was constructed using the broad-host-range vector pRK293 and the plasmid pPM9, the latter one harbouring a gene encoding the Nap A acid phosphatase from M. morganii. The recombinant construction was transformed and expressed in E. coli MC1061. Transformant clones were selected and characterized, showing that the relative orientation of both original plasmids with respect to each other affected the expression of the gene, with one of the plasmids (pT4) expressing significantly lower values of activity than the opposite orientation construction (pT5). Zymograms developed to detect acid phosphatase activity also corroborated the gene expression in the E. coli host. The genetic constructions (pT4 and pT5) were transferred to B. cepacia IS-16 by conjugation. The same effect of the original plasmid orientation in the construction was corroborated in the B. cepacia IS-16 strain. Compared with the strain lacking the recombinant plasmid, no signifi-cant improvement of cell-bound enzymatic activity was achieved by the exconjugant harbouring pT5. However, a significant increase in the extracellular enzyme activity was detected in the recombinant strains. Nometabolic load due to the presence of the recombinant plasmid was detected in both E. coli and Burkholderia hosts.