The role of the luxS/autoinducer-2(AI-2)quorum sensing system in probiotic efficacy is controversial.This study investigated the therapeutic potential of a luxS-deficient mutant(△luxS)of Companilactobacillus crustoru...The role of the luxS/autoinducer-2(AI-2)quorum sensing system in probiotic efficacy is controversial.This study investigated the therapeutic potential of a luxS-deficient mutant(△luxS)of Companilactobacillus crustorum MN047 in a dextran sulfate sodium(DSS)-induced colitis mouse model.Unexpectedly,the△luxS mutant developed a pronounced auto-aggregation phenotype(>90%)and significantly enhanced bile salt tolerance in vitro.Mechanistically,these physical adaptations were driven by the redirection of carbon flux toward exopo-lysaccharide biosynthesis via the upregulation of specific phosphotransferase systems(PTS).In vivo,these traits translated into superior therapeutic efficacy compared to the wild-type.The mutant effectively alleviated colitis symptoms and restored intestinal barrier integrity.Furthermore,the mutant reshaped the gut microbiota,spe-cifically enriching short-chain fatty acid(SCFA)producers(Bacteroides and Marinifilaceae),which elevated anti-inflammatory metabolites.These findings indicate that targeted modulation of the LuxS/AI-2 system could be a viable strategy for engineering next-generation probiotics with enhanced physiological resilience.展开更多
Objectives:The screening of traditional fermented products is essential for the assessment of safety,security,and further development of functional foods for the well-being of human health.The aim of the present study...Objectives:The screening of traditional fermented products is essential for the assessment of safety,security,and further development of functional foods for the well-being of human health.The aim of the present study was to isolate and identify bacteria from fermented raw milk samples that exhibit health benefits upon consumption.Methods:In order to confirm the isolates as probiotics,several in vitro assays were conducted to assess the probiotic properties of isolated bacteria.The initial screening includes tolerance to acid,bile,pancreatin,and NaCl.The cell surface properties demonstrate their interaction with mucosal epithelium,which includes hydrophobicity and auto-aggregation assay.Safety assessment was done by performing haemolytic test and antibiotic susceptibility test.The antagonistic activity of probiotic strain was further evaluated against some pathogenic bacteria.Results:Lactobacillus plantarum(L.plantarum)isolated from fermented raw milk was preliminarily identified by biochemical tests and further confirmed using 16S rRNA identification.The isolate designated as L.plantarum strain GCC_19M1 demonstrated significant tolerance to low pH,0.3%bile,0.5%pancreatin,and 5%NaCl.In the presence of simulated gastric juice(at pH 3),the isolate exhibited a survival rate of 93.48-96.97%.Furthermore,the development of ecological niches in the human gut and their successful accumulation have been revealed by auto-aggregation and hydrophobicity properties.Absence of haemolytic activity ensures the non-virulent nature of the strain.Lactobacillus plantarum strain GCC_19M1 showed susceptibility towards gentamicin,tetracycline,kanamycin,meropenem,and ceftriaxone and exhibited an antagonistic effect on pathogenic bacteria.Conclusion:The obtained results conveyed that L.plantarum strain GCC_19M1 has strong probiotic potential,and its presence in the fermented raw milk products may serve as a potent functional probiotic food.展开更多
The objective of this study is to cultivate aerobic granules by pure bacterial strain,Bacillus thuringiensis,in a sequencing batch reactor.Stable granules sized 2.0–2.2 mm were formed in the reactor after a five-week...The objective of this study is to cultivate aerobic granules by pure bacterial strain,Bacillus thuringiensis,in a sequencing batch reactor.Stable granules sized 2.0–2.2 mm were formed in the reactor after a five-week cultivation.These granules exhibited excellent settling attributes,and degraded phenol at rates of 1.49 and 1.19 g phenol/(g VSS·d)at 250 and 1500 mg/L of phenol concentration,respectively.Confocal laser scanning microscopic test results show that Bacillus thuringiensis was distributed over the initial small aggregates,and the outer edge of the granule was away from the core regime in the following stage.展开更多
基金supported by the National Natural Science Foundation of China(No.32302260)the Scientific Research Program Funded by Shaanxi Provincial Education Department(No.25JC008)+1 种基金the Shaanxi Province Postdoctoral Science Foundation(No.2025BSHEDZZ031)Shandong Province postdoctoral Fund project(No.SDCX-ZG-202400136).
文摘The role of the luxS/autoinducer-2(AI-2)quorum sensing system in probiotic efficacy is controversial.This study investigated the therapeutic potential of a luxS-deficient mutant(△luxS)of Companilactobacillus crustorum MN047 in a dextran sulfate sodium(DSS)-induced colitis mouse model.Unexpectedly,the△luxS mutant developed a pronounced auto-aggregation phenotype(>90%)and significantly enhanced bile salt tolerance in vitro.Mechanistically,these physical adaptations were driven by the redirection of carbon flux toward exopo-lysaccharide biosynthesis via the upregulation of specific phosphotransferase systems(PTS).In vivo,these traits translated into superior therapeutic efficacy compared to the wild-type.The mutant effectively alleviated colitis symptoms and restored intestinal barrier integrity.Furthermore,the mutant reshaped the gut microbiota,spe-cifically enriching short-chain fatty acid(SCFA)producers(Bacteroides and Marinifilaceae),which elevated anti-inflammatory metabolites.These findings indicate that targeted modulation of the LuxS/AI-2 system could be a viable strategy for engineering next-generation probiotics with enhanced physiological resilience.
文摘Objectives:The screening of traditional fermented products is essential for the assessment of safety,security,and further development of functional foods for the well-being of human health.The aim of the present study was to isolate and identify bacteria from fermented raw milk samples that exhibit health benefits upon consumption.Methods:In order to confirm the isolates as probiotics,several in vitro assays were conducted to assess the probiotic properties of isolated bacteria.The initial screening includes tolerance to acid,bile,pancreatin,and NaCl.The cell surface properties demonstrate their interaction with mucosal epithelium,which includes hydrophobicity and auto-aggregation assay.Safety assessment was done by performing haemolytic test and antibiotic susceptibility test.The antagonistic activity of probiotic strain was further evaluated against some pathogenic bacteria.Results:Lactobacillus plantarum(L.plantarum)isolated from fermented raw milk was preliminarily identified by biochemical tests and further confirmed using 16S rRNA identification.The isolate designated as L.plantarum strain GCC_19M1 demonstrated significant tolerance to low pH,0.3%bile,0.5%pancreatin,and 5%NaCl.In the presence of simulated gastric juice(at pH 3),the isolate exhibited a survival rate of 93.48-96.97%.Furthermore,the development of ecological niches in the human gut and their successful accumulation have been revealed by auto-aggregation and hydrophobicity properties.Absence of haemolytic activity ensures the non-virulent nature of the strain.Lactobacillus plantarum strain GCC_19M1 showed susceptibility towards gentamicin,tetracycline,kanamycin,meropenem,and ceftriaxone and exhibited an antagonistic effect on pathogenic bacteria.Conclusion:The obtained results conveyed that L.plantarum strain GCC_19M1 has strong probiotic potential,and its presence in the fermented raw milk products may serve as a potent functional probiotic food.
文摘The objective of this study is to cultivate aerobic granules by pure bacterial strain,Bacillus thuringiensis,in a sequencing batch reactor.Stable granules sized 2.0–2.2 mm were formed in the reactor after a five-week cultivation.These granules exhibited excellent settling attributes,and degraded phenol at rates of 1.49 and 1.19 g phenol/(g VSS·d)at 250 and 1500 mg/L of phenol concentration,respectively.Confocal laser scanning microscopic test results show that Bacillus thuringiensis was distributed over the initial small aggregates,and the outer edge of the granule was away from the core regime in the following stage.
