AUTHOR=Hoshiko Yuki , Nishiyama Yoshito , Moriya Tae , Kadokami Kiwao , López-Jácome Luis Esaú , Hirano Ryutaro , García-Contreras Rodolfo , Maeda Toshinari 

TITLE=Quinolone Signals Related to Pseudomonas Quinolone Signal-Quorum Sensing Inhibits the Predatory Activity of Bdellovibrio bacteriovorus

JOURNAL=Frontiers in Microbiology

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2021.722579

DOI=10.3389/fmicb.2021.722579

ISSN=1664-302X

ABSTRACT=<p><italic>Bdellovibrio bacteriovorus</italic> is one of the predatory bacteria; therefore, it can act as a novel “living antibiotic,” unlike the current antibiotics. Here the predation of <italic>Escherichia coli</italic> by <italic>B. bacteriovorus</italic> was inhibited in the presence of <italic>Pseudomonas aeruginosa</italic>. This study investigated whether <italic>P. aeruginosa</italic>-induced predation inhibition is associated with bacterial quorum sensing (QS). Each <italic>las</italic>, <italic>rhl</italic>, or <italic>pqs</italic> QS mutant in <italic>P. aeruginosa</italic> was used to check the predatory activity of <italic>E. coli</italic> cells using <italic>B. bacteriovorus</italic>. As a result, the predatory activity of <italic>B. bacteriovorus</italic> increased in a mutant <italic>pqs</italic> QS system, whereas wild-type PA14 inhibited the predatory activity. Moreover, the addition of 4-hydroxy-2-heptylquinoline (HHQ) or the analog triggered the low predatory activity of <italic>B. bacteriovorus</italic> and killed <italic>B. bacteriovorus</italic> cells. Therefore, a defensive action of <italic>P. aeruginosa</italic> against <italic>B. bacteriovorus</italic> is activated by the <italic>pqs</italic> QS system, which produces some quinolone compounds such as HHQ.</p>