دانلود رایگان مقاله انگلیسی سیستم حسگر Quorum و اثر آن در فساد غذایی در شبه موناس فلورسنس سپرماهی - اشپرینگر 2018

Abstract

The spoilage of aquatic products is mainly caused by the bacterial growth, and the specific spoilage organism (SSO) plays an important role. Quorum sensing (QS) is a microbial cell–cell communication system which is coordinated with the population density, and is controlled by N-acyl-homoserine lactone (AHLs) as the Gramnegative bacteria communication signals. In this study, the SSO was Pseudomonas fluorescens (PF-04), isolated from the turbot (Scophthalmus maximus L.) during aerobically refrigerated storage. The supernatant extract of PF-04 tested the AHLs activities utilizing biosensor Chromobacterium violaceum CV026. AHL production was influenced by the environment temperature, and AHL production reduced obviously at 10 C compare with 25 C. In LuriaBertani (LB) supplemented with 0.5–1.0% NaCl, AHL production reached the maximum. The AHL production was also regulated by pH of culture medium, acidic condition was conducive to persistent existence of the AHL molecules, but the alkaline environment would cause chemically unstable of AHL molecules. QS system in P. flurosecens played an imperative role in biofilm formation, protease and siderophore production. AHLs could regulate above three factors in PF-04. In summary, this study showed that (1) the influence of different environmental conditions (temperature, NaCl and pH) on AHL production revealed the correlation of QS in foods and (2) that proved the effect of external AHLs to regulate the biofilm formation, protease and siderophore production in PF-04.

Conclusion

In the present study, the biosensor assays was an obviously semiquantitative method for detection of AHL production. AHL production was influenced by the different environment conditions. AHL production were reduced at 10 C when compared with 25 C. AHL production could reach maximum at 0.5–1.0% NaCl in LB supplemented. acidic conditions was conducive to the stable existence of the AHL molecules, but the alkaline environment was diametrically opposite. AHL-based quorum sensing system could up-regulate biofilm formation, production of protease and siderophore. Our group was currently building the LuxI/R genes deletion of P. fluorescens strain PF-04 to further demystify the correlation between quorum sensing and turbot spoilage.