ABSTRACT
Monitoring the extracellular environment for danger signals is a critical aspect of cellular survival. However, the danger signals released by dying bacteria and the mechanisms bacteria use for threat assessment remain largely unexplored. Here, we show that lysis of Pseudomonas aeruginosa cells releases polyamines that are subsequently taken up by surviving cells via a mechanism that relies on Gac/Rsm signaling. While intracellular polyamines spike in surviving cells, the duration of this spike varies according to the infection status of the cell. In bacteriophage-infected cells, intracellular polyamines are maintained at high levels, which inhibits replication of the bacteriophage genome. Many bacteriophages package linear DNA genomes and linear DNA is sufficient to trigger intracellular polyamine accumulation, suggesting that linear DNA is sensed as a second danger signal. Collectively, these results demonstrate how polyamines released by dying cells together with linear DNA allow P. aeruginosa to make threat assessments of cellular injury.
Subject(s)
Bacteriophages , Polyamines , Bacteriophages/genetics , Bacteria , Pseudomonas aeruginosa , DNAABSTRACT
vB_PaeP_CMS1 is a lytic bacteriophage that infects Pseudomonas aeruginosa. Whole-genome sequencing revealed that vB_PaeP_CMS1 has a linear double-stranded DNA (dsDNA) genome composed of 72,673 bp, with a GC content of 54.9%, that harbors 92 predicted open reading frames, with the greatest genome homology to members of the family Podoviridae, genus Litunavirus.
