Alginate Synthesis in Mucoid Pseudomonas aeruginosa: a Chromosomal Locus Involved in Control

Abstract

Mucoid variants of P. aeruginosa isolated in vitro or in vivo could be classified into 2 phenotypic groups based on whether alginate was produced on a chemically defined medium. Mucoid strains yielded lower recombination frequencies than the nonmucoid parent when used as donors in FP2-mediated plate matings. The mucoid characteristic (muc) was co-inherited by a proportion of recombinants selected for the inheritance of chromosomal markers his-5075+ or cys-5605+. The results of further experiments using either a mucoid recipient or a mucoid donor carrying plasmid R68.45 suggested that the control of alginate production in P. aeruginosa involves at least 1 chromosomal locus.