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

Abstract

Quorum sensing is a cell-cell communication mechanism mediated by chemical signals that leads to differential gene expression in response to high population density. Salmonella is unable to synthesize the autoinducer-1 (AI-1), N-acyl homoserine lactone (AHL), but is able to recognize AHLs produced by other microorganisms through SdiA protein. This study aimed to evaluate the fatty acid and protein profiles of Salmonella enterica serovar Enteritidis PT4 578 throughout time of cultivation in the presence of AHL. The presence of N-dodecanoyl-homoserine lactone (C12-HSL) altered the fatty acid and protein profiles of Salmonella cultivated during 4, 6, 7, 12 and 36 h in anaerobic condition. The profiles of Salmonella Enteritidis at logarithmic phase of growth (4 h of cultivation), in the presence of C12-HSL, were similar to those of cells at late stationary phase (36 h). In addition, there was less variation in both protein and fatty acid profiles along growth, suggesting that this quorum sensing signal anticipated a stationary phase response. The presence of C12-HSL increased the abundance of thiol related proteins such as Tpx, Q7CR42, Q8ZP25, YfgD, AhpC, NfsB, YdhD and TrxA, as well as the levels of free cellular thiol after 6 h of cultivation, suggesting that these cells have greater potential to resist oxidative stress. Additionally, the LuxS protein which synthesizes the AI-2 signaling molecule was differentially abundant in the presence of C12-HSL. The NfsB protein had its abundance increased in the presence of C12-HSL at all evaluated times, which is a suggestion that the cells may be susceptible to the action of nitrofurans or that AHLs present some toxicity. Overall, the presence of C12-HSL altered important pathways related to oxidative stress and stationary phase response in Salmonella.

Inhibition of Staphylococcus aureus and Pseudomonas aeruginosa biofilms by quatsomes in low concentrations

“…Based on this, bacteria in the late logarithmic growth phase were selected for the anti-planktonic bacteria study. 21,22…”

“…Based on this, bacteria in the late logarithmic growth phase were selected for the anti-planktonic bacteria study. 21,22 For the anti-biofilm experiments, flat clear-bottom 96 well microplates (Corning Incorporated, Corning NY, USA) were used to grow biofilms. The microplates containing 150 mL of the bacterial suspension in each well were incubated for 48 h at 37 C on a gyratory shaker (Ratek Instruments, Boronia, VIC, Australia) at 70 r/min to allow for biofilm formation.…”

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

“…The choice of C12-HSL was based on studies showing its increased effect on biofilm formation by Salmonella compared to other AHLs with shorter carbon chains due to its higher affinity to SdiA. The concentration too was based on those same studies ( Campos-Galvão et al, 2015 , 2016 ; Almeida et al, 2016 , 2017b , 2018 ). The acetonitrile concentration was less than 1% (vol/vol) in the culture medium since according to Michael et al (2001) , this concentration does not exhibit an effect on the growth and response of Salmonella to AHL.…”

“…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 ). However, despite the evidence of the association between cell density-dependent gene expression, so far, there is a paucity of information related to the overall impact of AI-1 on the metabolism of Salmonella Enteritidis.…”

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

“…Changes in their expression levels are achieved once the signal molecules reach a given threshold (Fuqua et al, 1994). It controls bacterial functions such as biofilm formation, resistance to acid stress, motility, competence, and morphological modifications (Huang et al, 2016;Johansen and Jespersen, 2017;de Almeida et al, 2018). Gram-negative bacteria use small diffusible molecules called autoinducers such as indole (Lee et al, 2015), acylhomoserine lactones, autoinducer-2 (Galloway et al, 2011), and alkyl-quinolone (Pesci et al, 1999) among others-for example, P. aeruginosa also regulates the gene expression of some virulence factors by using four QS systems directly or indirectly: las regulation system, rhl regulation system, pqs regulation system, and iqs regulation system (Winson et al, 1995;Latifi et al, 1996;Pesci et al, 1997Pesci et al, , 1999McKnight et al, 2000;Gallagher et al, 2002;Kiratisin et al, 2002;Déziel et al, 2004;Xiao et al, 2006;Lee et al, 2013).…”