Changes in the proteome of Salmonella enterica serovar Thompson as stress adaptation to sublethal concentrations of thymol

Abstract

Thymol is a natural biocide and component of some essential oils from herbs. Its inhibitory effect on the growth of different microorganisms is well documented. The precise targets of the antibacterial action of thymol is not yet been fully established, the action seems to take place in different ways. The strain Salmonella enterica serovar Thompson MCV1 was grown in the presence of a sublethal concentration (0.01%) of thymol. The proteins extracted from treated and untreated cells were subjected to 2-D PAGE, followed by in-gel spot digestion and subsequent MALDI-TOF analysis. The analysis of gels showed many proteins that were either upregulated or downregulated by the presence of thymol, with significant changes in proteins belonging to different functional classes. In particular, the thioredoxin-1 was not expressed in the treated cells, indicating that its absence could be a consequence of the stress caused by the presence of thymol. On the other hand, different chaperon proteins were upregulated or de novo synthesis such as GroEL and DnaK, key proteins in the protection mechanism toward thermal stress. Outer membrane proteins were upregulated in treated cells; indeed the bacterial envelope stress response is trigged by the accumulation of misfolded outer membrane proteins. Moreover, the thymol seems to impair the citrate metabolic pathway, as well as many enzymes involved in the synthesis of ATP. Definitely, thymol plays a role in altering very different pathways of cell metabolism.

Bioactivity of Essential Oils From Medicinal Plants of Cameroon and Their Combination Against Infant Diarrhea Induced by Bacteria

“…Aldehydes act against bacterial cells by inducing the inhibition of cell proliferation through DNA and enzyme proteins binding to enhance the bacterial death (Dorman and Deans, 2000). In, Escherichia coli, Salmonella typhimurium and Listeria monocitogenes, citral permeabilizes and damages the cell membrane (Di Pasqua et al, 2010;Nguefack et al, 2012). This could justify the bactericidal effect of its EO observed against the sensitive strains used.…”

Adaptation of Salmonella to Antimicrobials in Food-Processing Environments

“…Different chaperon proteins were up-regulated or de novo synthesized, such as GroEL and Dnak which are key proteins in protecting cells against stress. Outer membrane proteins were also up-regulated in the presence of thymol (Di Pasqua et al, 2010). Moreover, the membrane fatty acid composition was markedly modified during growth in the presence of plant-derived terpenes such as carvacrol, thymol, citral or eugenol (Dubois-Brissonnet et al, 2011).…”

“…Little is known today about bacterial adaptation to plant-derived compounds, notably in the case of Salmonella. Nevertheless, the presence of thymol during the growth of S. Thompson induced the up-or down-regulation of many proteins (Di Pasqua et al, 2010). Different chaperon proteins were up-regulated or de novo synthesized, such as GroEL and Dnak which are key proteins in protecting cells against stress.…”

Adaptação e adaptação cruzada de Listeria monocytogenes aos compostos eugenol e carvacrol

“…Geralmente quando as bactérias são expostas ao estresse induzido por substâncias tóxicas ocorre o aumento na síntese das proteínas de estresse ou HSPs. Essas proteínas (HSPs) pertencem as famílias das chaperones tendo papel importante na montagem de polipeptídeos recém sintetizados, em sua conformação nativa e no dobramento e reparação das proteínas do citosol (Di Pasqua et al, 2010) A adaptação de L.monocytogenes ao carvacrol e eugenol e a adaptação cruzada pode ter ocorrido por diversos fatores. Um deles poderia ser como o ocorrido em Bacillus cereus, onde seu cultivo em presença de concentrações subletais de carvacrol promoveu a diminuição da fluidez da membrana citiplasmática devido a alterações na constituição dos acidos graxos.…”