(P27-025-24) Physicochemical Conditions Affecting Production of Cyclo(L-Phe-L-Pro), a Signal for Pathogenicity in the Food-Poisoning Pathogen Vibrio vulnificus
Kun-Soo Kim: No relevant financial relationship(s) with ineligible companies to disclose.
Objectives: Vibrio vulnificus is a pathogen responsible for severe food poisoning and can cause septicemia in humans. This pathogen, along with other pathogenic Vibrio spp., produces cyclo(L-Phe-L-Pro)(cFP) as a signaling molecule closely associated with pathogenesis. Understanding the conditions that affect cFP production is crucial for the controlling the food-related diseases caused by Vibrioceaea. This study examines environmental conditions influencing cFP production in V. vulnificus.
Methods: cFP levels in culture supernatants of V. vulnificus grown under various conditions were assessed using HPLC with a C18 reverse-phase column and 30% methanol as the mobile phase. The amount of cFP fractionated was estimated using chemically syhthesized cFP as a standard.
Results: We observed that the production levels during the late stationary phase. Production was greater in cells grown in rich media compared to minimal media and was higher at 37oC than at 28oC or 30oC. Additionally, the production was at least 60% higher at physiological concentration (0.9%) compared to high concentration of NaCl (3.9%). Increased production was also noted in the absence of iron and in the presence of sheep blood, whereas bile salts, glucose, and Casamino acid did not significantly affect the production. Interestingly, cFP production was medium concentration-dependent when the cells were grown in Luria Bertani (LB) broth from Neogen but not in LB medium from Difco. Further investigation revealed that the yeast extract in LB broth from Neogen contains components that promote cFP production. We isolated these components from the ethyl acetate extract of the yeast extract from Neogen and HPLC fractionation, which facilitated cFP production in V. vulnificus.
Conclusions: Our findings suggest that cFP production is enhanced under conditions mimicking the human body, implying that avoiding these conditions could reduce the risk of diseases caused by these pathogens.
Funding Sources: Korean Research Foundation. The funding number: 2022R1A2C1008958.
