Insights into the Mode of Action of Benzyl Isothiocyanate on Campylobacter jejuni

Abstract

cCampylobacter jejuni is a widespread pathogen responsible for most of the food-borne gastrointestinal diseases in Europe. The use of natural antimicrobial molecules is a promising alternative to antibiotic treatments for pathogen control in the food industry. Isothiocyanates are natural antimicrobial compounds, which also display anticancer activity. Several studies described the chemoprotective effect of isothiocyanates on eukaryotic cells, but the antimicrobial mechanism is still poorly understood. We investigated the early cellular response of C. jejuni to benzyl isothiocyanate by both transcriptomic and physiological approaches. The transcriptomic response of C. jejuni to benzyl isothiocyanate showed upregulation of heat shock response genes and an impact on energy metabolism. Oxygen consumption was progressively impaired by benzyl isothiocyanate treatment, as revealed by high-resolution respirometry, while the ATP content increased soon after benzyl isothiocyanate exposition, which suggests a shift in the energy metabolism balance. Finally, benzyl isothiocyanate induced intracellular protein aggregation. These results indicate that benzyl isothiocyanate affects C. jejuni by targeting proteins, resulting in the disruption of major metabolic processes and eventually leading to cell death.

Antibiotic and Antibiofilm Activities of Salvadora persica L. Essential Oils against Streptococcus mutans: A Detailed Comparative Study with Chlorhexidine Digluconate

“…It has been demonstrated that benzyl isothiocynate, the main constituent of the tested essential oils, results in impaired respiration and intracellular protein aggregation in Campylobacter jejuni, resulting in the inhibition of various metabolic activities [22]. This is supported by the observations that in MTT assays metabolic activity of S. mutans cells decreased when exposed to essential oils ( Figure 5A).…”

The antibacterial properties of isothiocyanates

“…jejuni and promoted protein aggregation in treated Ca. jejuni cells (Dufour et al, 2013). This effect may contribute to the antimicrobial action of ITC in bacterial cells (Fig.…”

“…We have recently performed a whole transcriptomic analysis of Campylobacter jejuni treated with subinhibitory concentrations of BITC (Dufour et al, 2013). We had previously determined the MIC and bactericidal action of BITC on several Ca.…”

“…It is interesting to note that this upregulation is correlated with an increase in ATP content in BITC-treated Ca. jejuni cells, along with an overexpression of genes from the TCA cycle and respiratory pathways such as nitrate reductase, lactate oxidase, hydrogenases and fumarate reductase (Dufour et al, 2013). In E. coli, an aerobic organism for which O 2 is the preferential electron acceptor, treatment with 2-(4-hydroxyphenyl)ethyl ITC decreased the cellular content of ATP (Tajima et al, 1998).…”

“…Interestingly, the transcriptomic analysis of Ca. jejuni exposed to BITC showed the upregulation of the thioredoxin gene trxA (Dufour et al, 2013). The thioredoxin/thioredoxin reductase systems are often redundant with the GSH/glutaredoxin/glutathione reductase system or can replace it (Toledano et al, 2007).…”