Specific Gene Expression in U Shows New Alternatives for Cadaverine and Putrescine Catabolism.

strain U can be grown using, as sole carbon sources, the biogenic amines putrescine or cadaverine, as well as their catabolic intermediates, ɣ-aminobutyrate or δ-aminovalerate, respectively. Several paralogs for the genes that encode some of the activities involved in the catabolism of these compounds, such as a putrescine-pyruvate aminotransferase ( and genes) and a ɣ-aminobutyrate aminotransferase ( and genes) have been identified in this bacterium. When the expression pattern of these genes is analyzed by qPCR, it is drastically conditioned by supplying the carbon sources. Thus, is upregulated by putrescine, whereas seems to be exclusively induced by cadaverine. However, increases its expression in response to different polyamines or aminated catabolic derivatives from them (i.e., ɣ-aminobutyrate or δ-aminovalerate), although does not change its expression level concerning no-amine unrelated carbon sources (citrate). These results reveal differences between the mechanisms proposed for polyamine catabolism in and concerning strain U, as well as allow a deeper understanding of the enzymatic systems used by this last strain during polyamine metabolism.