Acyl homoserine lactone changes the abundance of proteins and the levels of organic acids associated with stationary phase in Salmonella Enteritidis

Abstract

Quorum sensing (QS) is cell-cell communication mechanism mediated by signaling molecules known as autoinducers (AIs) that lead to differential gene expression. Salmonella is unable to synthesize the AI-1 acyl homoserine lactone (AHL), but is able to recognize AHLs produced by other microorganisms through SdiA protein. Our study aimed to evaluate the influence of AI-1 on the abundance of proteins and the levels of organic acids of Salmonella Enteritidis. The presence of N-dodecyl-homoserine lactone (C12-HSL) did not interfere on the growth or the total amount of extracted proteins of Salmonella. However, the abundance of the proteins PheT, HtpG, PtsI, Adi, TalB, PmgI (or GpmI), Eno, and PykF enhanced while the abundance of the proteins RplB, RplE, RpsB, Tsf, OmpA, OmpC, OmpD, and GapA decreased when Salmonella Enteritidis was anaerobically cultivated in the presence of C12-HSL. Additionally, the bacterium produced less succinic, lactic, and acetic acids in the presence of C12-HSL. However, the concentration of extracellular formic acid reached 20.46 mM after 24 h and was not detected when the growth was in the absence of AI-1. Considering the cultivation period for protein extraction, their abundance, process and function, as well as the levels of organic acids, we observed in cells cultivated in presence of C12-HSL a correlation with what is described in the literature as entry into the stationary phase of growth, mainly related to nitrogen and amino acid starvation and acid stress. Further studies are needed in order to determine the specific role of the differentially abundant proteins and extracellular organic acids secreted by Salmonella in the presence of quorum sensing signaling molecules.

N-dodecanoyl-homoserine lactone influences the levels of thiol and proteins related to oxidation-reduction process in Salmonella

“…Based on these similarities, these results suggest that AI-1 can anticipate a stationary phase response. Moreover, these results corroborate our previous observation, in which the differentially abundant proteins and organic acids of Salmonella cultivated for 7 h in the presence of C12-HSL correlated with entry into the stationary phase of growth, mainly in relation to nitrogen and amino acid starvation as well as acid stress [ 35 ]. Schuster et al [ 36 ] showed that genes with expression influenced by the growth phase in P .…”

“…Inoculum was prepared according to Almeida et al [ 35 , 41 ]. Tryptone soy broth (TSB; Sigma-Aldrich, India) was prepared with CO 2 under O 2 -free conditions, dispensed in anaerobic bottles that were sealed with butyl rubber stoppers and then autoclaved (anaerobic TSB).…”

“…A global analysis was carried out on the influence of AHL on the abundance of proteins and the levels of extracellular organic acids of Salmonella Enteritidis [ 35 ]. It was shown that the abundance of proteins involved in translation (PheT), transport (PtsI), metabolic processes (TalB, PmgI, Eno and PykF) and response to stress (HtpG and Adi) increased while the abundance of other proteins related to translation (RplB, RplE, RpsB and Tsf), transport (OmpA, OmpC and OmpD) and metabolic processes (GapA) decreased at 7 h of cultivation in the presence of AI-1.…”

Salmonella enterica Optimizes Metabolism After Addition of Acyl-Homoserine Lactone Under Anaerobic Conditions

“…Similar behavior was observed in the etiological agent of bubonic plague Yersinia pestis , in which RNAseq analyses demonstrated that the ptsI gene was downregulated in the wild-type compared to an AHL-null strain during the logarithmic growth phase ( LaRock et al, 2013 ). The equal glucose absorption levels after 7 h of cultivation ( Figure 1 ) can be justified by a 1.57-fold increase in the abundance of PtsI protein (phosphoenolpyruvate protein phosphotransferase) in Salmonella Enteritidis PT4 578 at the same time and cultivation in TSB anaerobic medium supplemented with C12-HSL reported by Almeida et al (2017a) .…”

“…Besides C12-HSL, other AHLs tested did not influence the growth of Salmonella Enteritidis PT4 578 cultivated in anaerobic Tryptic Soy Broth (TSB) medium at 37°C ( Campos-Galvão et al, 2015 ; Almeida et al, 2017b ). Cultivation of Salmonella Enteritidis PT4 578 in anaerobic TSB medium supplemented with C12-HSL also led to alterations in protein abundance and levels of organic acids associated with the early stationary phase of growth ( Almeida et al, 2017a ). It also increases the expression of thiol-related proteins and thiol, as well as the alteration in the fatty acid profile ( Almeida et al, 2018 ).…”