Hafnia alvei,a predominant spoilage bacterium in aquatic products,regulates its spoilage phenotypes through an N-acyl homoserine lactone(AHL)-mediated quorum sensing(QS)system.Penicillin G acylase(PGA),an ecofriendly ...Hafnia alvei,a predominant spoilage bacterium in aquatic products,regulates its spoilage phenotypes through an N-acyl homoserine lactone(AHL)-mediated quorum sensing(QS)system.Penicillin G acylase(PGA),an ecofriendly quorum-quenching enzyme,and chlorogenic acid(CGA),a natural polyphenolic compound with antioxidant and antibacterial properties,were investigated for their combined inhibitory effects on QS and biofilm formation in H.alvei.Results showed that the PGA-CGA combination exhibited strong biofilm inhibition(29.88%-59.18%)and clearance(30.61%-55.45%)compared to individual treatments.Scanning electron microscopy revealed that PGA-CGA disrupted biofilm architecture,yielding thinner structures and dispersed bacterial col-onies.Furthermore,the combination significantly suppressed some spoilage phenotypes,including violacein production,extracellular polysaccharide synthesis,biogenic amine accumulation,siderophore secretion,lipase activity,and motility,with inhibition rates ranging from 28.94%to 100%.Real-time PCR analysis revealed that PGA-CGA synergistically downregulated QS-associated(halI and halR),biofilm-related(flgA),spoilage-related(dppF),and motility-related(motB and kdsD)genes by 30%-60%,surpassing the effects of individual treatments.Metabolomic profiling further demonstrated that the combination disrupted carbohydrate and energy metabolism,amino acid and nucleotide biosynthesis,and biotin metabolism.Additionally,the PGA-CGA reduced the levels of total viable counts and total volatile base nitrogen in salmon fillets,and maintained good sensory quality during 12 d of storage.Therefore,the PGA-CGA combination is proposed as a promising novel agent for fish preservation.展开更多
To mitigate food contamination caused by multi-species biofilms,the inhibitory effect of peptide SF on dual-species biofilms was investigated in the study.Vibrio parahaemolyticus frequently engages in intercommunica-t...To mitigate food contamination caused by multi-species biofilms,the inhibitory effect of peptide SF on dual-species biofilms was investigated in the study.Vibrio parahaemolyticus frequently engages in intercommunica-tion with other bacteria through the autoinducer-2(AI-2)/LuxS quorum sensing system,contributing to the biofilm formation.However,the knowledge of quorum sensing inhibitors(QSIs)that target dual-species biofilms involving V.parahaemolyticus has remained limited.Therefore,this study constructed dual-species biofilms of V.parahaemolyticus and Aeromonas sobria,assessed AI-2 activity,and investigated the inhibitory effect of the QSI peptide Ser-Phe(SF)on these biofilms.The results indicated that peptide SF(1 mg/mL)significantly inhibited AI-2 activity,production of extracellular polysaccharides,proteins,DNA,metabolic activity,hydrophobicity,and auto-aggregation of these biofilms.The inhibitory rates to the both dual-species and V.parahaemolyticus mono-species were 44.40%and 47.31%for AI-2 activity,31.29%and 63.84%for extracellular polysaccharides,53.64%and 48.61%for extracellular proteins,55.38%and 52.58%for extracellular DNA,46.18%and 24.46%for metabolic activity,67.46%and 50.61%for hydrophobicity,and 44.15%and 51.98%for auto-aggregation.Moreover,scanning electron microscopy revealed the disruption of the structure in dual-species biofilms treated with peptide SF.The qRT-PCR results demonstrated that peptide SF down-regulated the expression of key genes related to quorum sensing(luxS and luxP),flagellum(flaA),virulence factors(toxR),and extracellular polymeric substances(cpsA)in the dual-species.However,peptide SF did not inhibit AI-2 activity or biofilm formation in A.sobria.This study will provide a QSI for controlling multi-species biofilms caused by V.parahaemolyticus.展开更多
基金supported by the Open Foundation of Oceanology Research Institute of Bohai University(BDHYYJY2024001)the Key Research and Development Program Project of Liaoning Province Science and Technology Joint Plan(2025JH2/101800321).
文摘Hafnia alvei,a predominant spoilage bacterium in aquatic products,regulates its spoilage phenotypes through an N-acyl homoserine lactone(AHL)-mediated quorum sensing(QS)system.Penicillin G acylase(PGA),an ecofriendly quorum-quenching enzyme,and chlorogenic acid(CGA),a natural polyphenolic compound with antioxidant and antibacterial properties,were investigated for their combined inhibitory effects on QS and biofilm formation in H.alvei.Results showed that the PGA-CGA combination exhibited strong biofilm inhibition(29.88%-59.18%)and clearance(30.61%-55.45%)compared to individual treatments.Scanning electron microscopy revealed that PGA-CGA disrupted biofilm architecture,yielding thinner structures and dispersed bacterial col-onies.Furthermore,the combination significantly suppressed some spoilage phenotypes,including violacein production,extracellular polysaccharide synthesis,biogenic amine accumulation,siderophore secretion,lipase activity,and motility,with inhibition rates ranging from 28.94%to 100%.Real-time PCR analysis revealed that PGA-CGA synergistically downregulated QS-associated(halI and halR),biofilm-related(flgA),spoilage-related(dppF),and motility-related(motB and kdsD)genes by 30%-60%,surpassing the effects of individual treatments.Metabolomic profiling further demonstrated that the combination disrupted carbohydrate and energy metabolism,amino acid and nucleotide biosynthesis,and biotin metabolism.Additionally,the PGA-CGA reduced the levels of total viable counts and total volatile base nitrogen in salmon fillets,and maintained good sensory quality during 12 d of storage.Therefore,the PGA-CGA combination is proposed as a promising novel agent for fish preservation.
基金supported by the Open Foundation of Oceanology Research Institute of Bohai University(BDHYYJY2020002).
文摘To mitigate food contamination caused by multi-species biofilms,the inhibitory effect of peptide SF on dual-species biofilms was investigated in the study.Vibrio parahaemolyticus frequently engages in intercommunica-tion with other bacteria through the autoinducer-2(AI-2)/LuxS quorum sensing system,contributing to the biofilm formation.However,the knowledge of quorum sensing inhibitors(QSIs)that target dual-species biofilms involving V.parahaemolyticus has remained limited.Therefore,this study constructed dual-species biofilms of V.parahaemolyticus and Aeromonas sobria,assessed AI-2 activity,and investigated the inhibitory effect of the QSI peptide Ser-Phe(SF)on these biofilms.The results indicated that peptide SF(1 mg/mL)significantly inhibited AI-2 activity,production of extracellular polysaccharides,proteins,DNA,metabolic activity,hydrophobicity,and auto-aggregation of these biofilms.The inhibitory rates to the both dual-species and V.parahaemolyticus mono-species were 44.40%and 47.31%for AI-2 activity,31.29%and 63.84%for extracellular polysaccharides,53.64%and 48.61%for extracellular proteins,55.38%and 52.58%for extracellular DNA,46.18%and 24.46%for metabolic activity,67.46%and 50.61%for hydrophobicity,and 44.15%and 51.98%for auto-aggregation.Moreover,scanning electron microscopy revealed the disruption of the structure in dual-species biofilms treated with peptide SF.The qRT-PCR results demonstrated that peptide SF down-regulated the expression of key genes related to quorum sensing(luxS and luxP),flagellum(flaA),virulence factors(toxR),and extracellular polymeric substances(cpsA)in the dual-species.However,peptide SF did not inhibit AI-2 activity or biofilm formation in A.sobria.This study will provide a QSI for controlling multi-species biofilms caused by V.parahaemolyticus.
