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Numerous bacteria communicate via a small interspecits-specific signalling molecule autoinducer-2 (AI-2) generated via LuxS. Many bacterial species use communication (Quorum sensing) modulating physiological functions and expression of virulence factors. However, little is known about AI-2 activity in Campylobacter species. In the literature the role of Quorum sensing in C. jejuni is discussed diversely. Analyses of ΔluxS mutant strains show various results. These are sometimes opposing results, which may be due to different experimental settings. For example temperature and growth phase seems to play an important role. Furthermore, the authors used different strains of C. jejuni ΔluxS mutant to confirm their studies. Additionally, most studies lack proof of complementing the ΔluxS mutant strains with AI-2 and/or a metabolic substance to confirm whether resulting phenotypes are due to metabolic function of LuxS or a consequence of disrupting cell communication. In this study we compare two ΔluxS mutant strains of C. jejuni in growth and motility, at different
temperatures (37°C, 42°C) in parallel. Furthermore we complemented each experiment with synthetic AI-2 or homocysteine as well as both combined. Moreover we examine the effect of AI-2 on C. jejuni wildtypt and ΔluxS mutant gene expression. Our results show that addition of AI-2 induces a change in gene expression patterns, so we hypothesize that either a receptor for AI-2 might exist in C. jejuni respectively an active AI-2 import into the cell takes place. However, our data show that AI2 in C. jejuni ΔluxS mutant is not imported through an ABC transporter system.