Polyamines Are Required for Virulence in Salmonella enterica Serovar Typhimurium
Figure 1
Gene organization and graphic representation of putrescine/spermidine transporters and biosynthesis pathways.
(A) The putrescine and spermidine transporters are localized at three distinct loci; potABCD interrupted by sifA, potFGHI, and potE. The genotype of the transporter mutant (potCD;I;E) is indicated by an asterix above deleted genes. Below is shown a graphic presentation of the transporters with their substrate affinity indicated by p for putrescine and s for spermidine. Expression during infection of cell-cultures is indicated above genes [36], [37]. (B) The putrescine and spermidine biosynthesis genes are localized at five distinct genetic loci; speA, speB, speC, speDE, and speF. The genotype of the biosynthesis mutant (speB;C;E;F) is indicated by an asterix above deleted genes. Below is shown a graphic presentation of the biosynthesis pathways present in bacteria, reviewed in [67]. SAM: S-adenosylmethionine.