Fig. 4.

Putative functions of orthologous prophages conserved in their hosts. (1) Functional prophages can be used as molecular weapons to kill nonlysogens through the production of infective particles. (2) Defective prophages can produce noninfective particles (phage killer particles and R/F-type bacteriocins) that kill sensitive cells. (3) Prophages can form transducing particles and gene transfer agents (GTAs) that promote host DNA exchange (displayed in green). (4) Degraded prophages might interfere with the assembly of other phages (represented in red) leading to the formation of defective particles. (5) Prophage structural proteins often display Ig-like domains that might be used by their hosts for adherence in niche colonization.