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

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

doi:10.3389/fmicb.2021.722579

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

Front Microbiol. 2021 Sep 10:12:722579. doi: 10.3389/fmicb.2021.722579. eCollection 2021.

Authors

Yuki Hoshiko¹, Yoshito Nishiyama¹, Tae Moriya¹, Kiwao Kadokami², Luis Esaú López-Jácome^{3

4}, Ryutaro Hirano¹, Rodolfo García-Contreras³, Toshinari Maeda¹

Affiliations

¹ Department of Biological Functions Engineering, Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, Kitakyushu, Japan.
² Institute of Environmental Science and Technology, The University of Kitakyushu, Kitakyushu, Japan.
³ Department of Microbiology and Parasitology, Faculty of Medicine, UNAM, Mexico City, Mexico.
⁴ Laboratory of Infectology, National Institute of Rehabilitation Luis Guillermo Ibarra Ibarra, Mexico City, Mexico.

Abstract

Bdellovibrio bacteriovorus is one of the predatory bacteria; therefore, it can act as a novel "living antibiotic," unlike the current antibiotics. Here the predation of Escherichia coli by B. bacteriovorus was inhibited in the presence of Pseudomonas aeruginosa. This study investigated whether P. aeruginosa-induced predation inhibition is associated with bacterial quorum sensing (QS). Each las, rhl, or pqs QS mutant in P. aeruginosa was used to check the predatory activity of E. coli cells using B. bacteriovorus. As a result, the predatory activity of B. bacteriovorus increased in a mutant pqs 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 B. bacteriovorus and killed B. bacteriovorus cells. Therefore, a defensive action of P. aeruginosa against B. bacteriovorus is activated by the pqs QS system, which produces some quinolone compounds such as HHQ.

Keywords: Bdellovibrio bacteriovorus; Escherichia coli; Pseudomonas aeruginosa; Pseudomonas quinolone signal; inhibition factors; predatory bacteria; quorum sensing.