Objectives:Staphylococcus aureus(MRSA)is widely acknowledged as a significant threat to food safety and human health.This research focused on the characteristics of bacteriocin Q13 produced by Lactococcus lactis Q13 i...Objectives:Staphylococcus aureus(MRSA)is widely acknowledged as a significant threat to food safety and human health.This research focused on the characteristics of bacteriocin Q13 produced by Lactococcus lactis Q13 isolated from the traditional Chinese fermented food hairy tofu.Materials and Methods:The biosynthetic gene clusters of bacteriocins were identified through whole-genome sequencing of L.lactis Q13.The antibacterial activity of its cell-free supernatant was assessed against MRSA and other Gram-positive bacteria.Subsequently,bacteriocin Q13 was purified through ammonium sulfate precipitation,Sephadex G-50 gel filtration chromatography,and reversed-phase high-performance liquid chromatography.Its molecular weight was determined via matrix-assisted laser desorption/ionization time-of-flight mass spectrometry,and structural features were analyzed by Fourier-transform infrared spectroscopy.Stability of bacteriocin Q13 under various conditions(enzymes,organic solvents,surfactants,metal ions,UV exposure,Na Cl concentration,and storage time and temperature)was evaluated.The antimicrobial mode of action was investigated via scanning electron microscopy(SEM).Results:Bacteriocin Q13 exhibited a significant bacteriostatic effect against MRSA and a broad spectrum of Gram-positive bacteria.Its molecular weight was 19367.97 Da,with dominant secondary structures identified asβ-turn andβ-sheet.Bacteriocin Q13 demonstrated remarkable stability under different conditions.SEM analysis showed that bacteriocin Q13 was able to induce significant morphological changes in MRSA,including disruption of cellular morphology,impairment of membrane integrity,and leakage of cytoplasmic contents,revealing the bacteriostatic mechanism of bacteriocin Q13 against MRSA.Conclusions:Bacteriocin Q13 from L.lactis Q13 exhibits considerable potential as a natural antimicrobial compound for controlling MRSA contamination in food products.These results lay a scientific foundation for the application of L.lactis Q13 and its bacteriocin in the food industry as potential probiotics and preservatives.展开更多
基金supported by the WeiZhou Team Funds,Southwest Minzu University(No.SMUWZ202409),China。
文摘Objectives:Staphylococcus aureus(MRSA)is widely acknowledged as a significant threat to food safety and human health.This research focused on the characteristics of bacteriocin Q13 produced by Lactococcus lactis Q13 isolated from the traditional Chinese fermented food hairy tofu.Materials and Methods:The biosynthetic gene clusters of bacteriocins were identified through whole-genome sequencing of L.lactis Q13.The antibacterial activity of its cell-free supernatant was assessed against MRSA and other Gram-positive bacteria.Subsequently,bacteriocin Q13 was purified through ammonium sulfate precipitation,Sephadex G-50 gel filtration chromatography,and reversed-phase high-performance liquid chromatography.Its molecular weight was determined via matrix-assisted laser desorption/ionization time-of-flight mass spectrometry,and structural features were analyzed by Fourier-transform infrared spectroscopy.Stability of bacteriocin Q13 under various conditions(enzymes,organic solvents,surfactants,metal ions,UV exposure,Na Cl concentration,and storage time and temperature)was evaluated.The antimicrobial mode of action was investigated via scanning electron microscopy(SEM).Results:Bacteriocin Q13 exhibited a significant bacteriostatic effect against MRSA and a broad spectrum of Gram-positive bacteria.Its molecular weight was 19367.97 Da,with dominant secondary structures identified asβ-turn andβ-sheet.Bacteriocin Q13 demonstrated remarkable stability under different conditions.SEM analysis showed that bacteriocin Q13 was able to induce significant morphological changes in MRSA,including disruption of cellular morphology,impairment of membrane integrity,and leakage of cytoplasmic contents,revealing the bacteriostatic mechanism of bacteriocin Q13 against MRSA.Conclusions:Bacteriocin Q13 from L.lactis Q13 exhibits considerable potential as a natural antimicrobial compound for controlling MRSA contamination in food products.These results lay a scientific foundation for the application of L.lactis Q13 and its bacteriocin in the food industry as potential probiotics and preservatives.
