Elucidation of the AI-2 communication system in the food-borne pathogen Campylobacter jejuni by whole-cell-based biosensor quantificationRamić, Dina (Avtor) Klančnik, Anja (Avtor) Smole Možina, Sonja (Avtor) Dogša, Iztok (Avtor) Campylobacter jejuniAI-2 quantificationbiosensor methodHPLC-FLDThe food-borne pathogen Campylobacter jejuni produces autoinducer-2 (AI-2) as an interspecies signalling molecule. AI-2 can trigger enhanced colonisation and biofilm formation, and this poses a serious risk to public health. To date, this communication system of C. jejuni is only partially understood, as detection and quantifi- cation of such autoinducer signalling molecules in complex media is hard to achieve. We have developed a whole-cell Vibrio harveyi-based biosensor assay to accurately quantify and follow production of AI-2 by C. jejuni 81–176 in a defined growth medium and in a model food system. Several V. harveyi strains were tested, but the most sensitive bioluminescent response to C. jejuni AI-2 was achieved with V. harveyi MM30, likely due to its ability to self-amplify the response to AI-2. The AI-2 concentrations measured by this biosensor were confirmed using an independent analytical method, HPLC-FLD, which we introduced for Campylobacter analytics for the first time. The AI-2 concentration produced by C. jejuni 81–176 in the model food system was ~5-fold that in the defined growth medium, at the same cell density. Together with the linear increments in AI-2 concentrations with cell density, this suggests that in C. jejuni, AI-2 represents a metabolic by-product rather than a true quorum- sensing molecule. This biosensor method is highly sensitive, as shown by the reduction in the limit of detection (by a factor of 100) compared to HPLC-FLD, and it enables quantification of AI-2 in complex matrices, such as food, which will help to improve the quality and safety of food production.20222022-09-05 13:32:30Članek v reviji139598UDK: 579.24/.26:53.082.9ISSN pri članku: 0956-5663DOI: 10.1016/j.bios.2022.114439COBISS_ID: 110249219sl