The influence of relative humidity (RH) on quasistatic current-voltage (I-V) characteristics of Bifidobacterium animalis subsp. lactis BB-12 thin layers was studied for the first time. The value of electrical conducti...The influence of relative humidity (RH) on quasistatic current-voltage (I-V) characteristics of Bifidobacterium animalis subsp. lactis BB-12 thin layers was studied for the first time. The value of electrical conductivity in 75% RH was found to be in the order of 10-7 (ohm·cm)-1, which was 106 orders of magnitude higher than that observed in dry atmosphere. It was concluded that RH played a key role in hysteresis behavior of the measured (I-V) characteristics. FTIR measurements showed that under water moisture environment, the associated bonds between amine and carboxyl group were greatly strengthened that was the source of free charge carries after ionization. The surface charge of Bifidobacterium animalis subsp. lactis BB-12 was found to be negative by zeta potential measurements, claiming that electrons were the charge carriers.展开更多
Sufu,a traditional fermented soybean curd,is prone to contamination by Bacillus cereus.In this study,133 lactic acid bacteria(LAB)strains were initially screened from spring and winter Mao-tofu samples for their abili...Sufu,a traditional fermented soybean curd,is prone to contamination by Bacillus cereus.In this study,133 lactic acid bacteria(LAB)strains were initially screened from spring and winter Mao-tofu samples for their ability to inhibit the growth of B.cereus ATCC 14579T.Among these strains,five Lactococcus lactis strains exhibited a good safety profile and were capable of growing in pH 4-9 and salt concentrations of 6%-8%.Antimicrobial experiments conducted on the B.cereus group from sufu factories showed that L.lactis LJL7m20 strain had the strongest inhibitory effect.Whole-genome sequencing revealed the presence of three genes associated with high osmotic stress response and eight distinct two-component systems that may contribute to the strain’s tolerance,enhancing its survival in high-salt environments.The strain was further identified as L.lactis subsp.lactis through a combination of phenotypic and genotypic analysis.Additionally,bacteriocins nisin Z and nisin A/Q were identified using the BAGEL4 and antiSMASH databases.ELISA further confirmed the strain’s ability to produce nisin.A fermentation validation study demonstrated that inoculation with the strain contributed to reduce the number of B.cereus group in sufu pehtzes.This study provides a theoretical foundation for the use of new biocontrol bacteria to improve the safety of traditional fermented soybean foods.展开更多
Lactic acid bacteria(LAB)are often exposed to ionizing radiation(IR)in the process of mutagenesis and food processing,and high doses of IR can cause damage and death to LAB.LlrG,a response regulator(RR)in twocomponent...Lactic acid bacteria(LAB)are often exposed to ionizing radiation(IR)in the process of mutagenesis and food processing,and high doses of IR can cause damage and death to LAB.LlrG,a response regulator(RR)in twocomponent system(TCS),holds a significant role in enabling LAB to adapt to the environment.In our previous study,the expression of LlrG protein in Lactococcus lactis subsp.lactis IL1403(L.lactis IL1403)was significantly increased after induction by IR.To explore the IR adaptation mechanism of L.lactis IL1403 regulated by LlrG,the gene llrG in L.lactis IL1403 was overexpressed(L.lactis IL1403-llrG)and the transcriptomics and proteomics were studied.Results showed that L.lactis IL1403-llrG had significantly higher survival rate and stronger antioxidant capacity under IR conditions compared with L.lactis IL1403-p(L.lactis IL1403 contained pMG36e).Meanwhile,the transcriptomics and proteomics analyses indicated that the overexpression of llrG resulted in the enhancement of oxidation-reduction process,response to stimulus and carbohydrate metabolism and the downregulation of amino acid biosynthesis.This research provided a new perspective on understanding the adaptive mechanism of L.lactis IL1403 response to IR based on LlrG.Furthermore,L.lactis strain with IRstress tolerance characteristic could act as a reference for the application in IR sterilization of probiotic fermented dairy products.展开更多
The target strain DB-8 in this study was isolated from naturally fermented yogurt residues in a herder’s house in Dangxiong County,Xizang.Multi-omics and genetic evolutionary analysis has been multidimensionally vali...The target strain DB-8 in this study was isolated from naturally fermented yogurt residues in a herder’s house in Dangxiong County,Xizang.Multi-omics and genetic evolutionary analysis has been multidimensionally validated the species attribute of DB-8,revealing traits in its metabolic properties and genetic evolution in high-altitude environments.In accordance with the data obtained from the whole genome sequence and genetic evolution of DB-8,the bacterium is confirmed to be Lactobacillus delbrueckii subsp.lactis.The results of genome functional annotation demonstrated that DB-8 possesses a multitude of distinctive genes pertaining to cell wall,membrane,envelope biosynthesis,carbohydrate metabolism,and energy metabolism.Comparative genomics analysis revealed that DB-8 has 122 specific genes that support its energy metabolism,cellular repair,and biofilm systems.It is also anticipated that these genes will have exceptionally strong acid resistance.Targeted metabolic studies confirm that DB-8 produces significantly more propionic acid and isobutyric acid than other reference strains.Furthermore,based on the results of the untargeted metabolomics study,44 different metabolites were screened to create support vector machine models based on t-test-based feature screening,with an accuracy of 0.92 for the model validation set and a prediction accuracy of 100%,which marks the first successful application of machine learning to predict subspecies characterization of Lactobacillus delbrueckii.This study offers novel ideas for the precise identification between Lactobacillus delbrueckii subsp.bulgaricus and subsp.lactis,while enhancing the understanding of the fermentation characteristics of DB-8,thereby offering a scientific basis for its in-depth application in the dairy industry.展开更多
Bifidobacterium animalis subsp.lactis is a well-known probiotic with potential benefits for alleviating sub-health symptoms,including immune dysfunction and anxiety.Given the strain-specific nature of its probiotic ef...Bifidobacterium animalis subsp.lactis is a well-known probiotic with potential benefits for alleviating sub-health symptoms,including immune dysfunction and anxiety.Given the strain-specific nature of its probiotic effects,identifying effective strains for sub-health alleviation is crucial.In this study,we characterized 16 B animalis subsp.lactis isolates from fecal samples and probiotic sources.We assessed the genotype-phenotype correlations related to growth,carbon source utilization,and stress tolerance in vitro.Subsequently,we profiled 107 metabolites(including 28 alcohols and 17 esters)and quantified the levels of short-chain fatty acids and three other organic acids.Three B.animalis strains,GOLDGUT-BB21,WLBA7,and WLBA6,were selected and evaluated in a sleep-deprived mouse model.In vivo,WLBA3 reduced inflammation and oxidative stress by inhibiting the NLRP3inflammasome pathway and modulating gut microbiota(e.g.,Lactobacillus and Alistipes),which in turn significantly improved weight gain and fatigue resistance,attenuated cognitive function,and anxiety-like behavior.These findings provide insights into the diversity of B.animalis subsp.lactis strain resources and highlight the potential of WLBA3 as a candidate for alleviating sub-health symptoms.展开更多
Depression is the main cause of the global mental health burden and was recently reported to be correlated with constipation[1,2].Scattered reports have demonstrated that the association between mood disorders and gas...Depression is the main cause of the global mental health burden and was recently reported to be correlated with constipation[1,2].Scattered reports have demonstrated that the association between mood disorders and gastrointestinal disturbances may be related to cross-talk between the gut and the central nervous system,referred to as the gut-brain axis[3].Recent studies reported that the gut microbiome facilitates gut-brain communication,and the importance of the microbiota–gut–brain axis in the pathogenesis of depression has become appreciated[4].展开更多
Lactococcus lactis subsp.lactis is a common starter culture in the dairy industry.In this study,the key pathway of five strains of Lactococcus lactis subsp.Lactis regarding their fermentation characteristics in milk s...Lactococcus lactis subsp.lactis is a common starter culture in the dairy industry.In this study,the key pathway of five strains of Lactococcus lactis subsp.Lactis regarding their fermentation characteristics in milk systems were studied by metabolomic approach,fermentation characterization and sensory evaluation.Strains DSCAB11M15 and DYNDL21-2,which express the cell wall proteinase PrtM/P,exhibited rapid proliferation and acidification,with significant differences in volatile and non-volatile metabolites including upregulation of flavor compounds such as ethyl butyrate and 2,3-butanedione.Additionally,DYNDL21-2,which carries theα-ketoacid decarboxylase gene,significantly increased the content of 3-methyl-butyric aldehyde,a compound that imparts a caramel-like flavor,in fermented milk.This study offers guidance for the comprehensive investigation of starter cultures with multiple approaches.展开更多
Among the low-cost nitrogen sources(dry spent yeast or DSY,rice bran,and soybean meal),DSY was identified as the most suitable supplement for lactic acid fermentation from sweet sorghum juice by Lactococcus lactis IO-...Among the low-cost nitrogen sources(dry spent yeast or DSY,rice bran,and soybean meal),DSY was identified as the most suitable supplement for lactic acid fermentation from sweet sorghum juice by Lactococcus lactis IO-1.However,lactic acid concentration(PL)using DSY was~22%lower than the control nitrogen source,yeast extract(YE).Statistical analysis using YE as a control nitrogen source revealed optimal conditions of 74.70 g/L of initial sugar and 15.20 g/L of YE,achieving a PL of 71.95 g/L and a 91.63%sugar consumption(SC).When DSY(22.61 g/L)containing an equivalent nitrogen content to the optimal YE was tested,PL and SC decreased to 55.13 g/L and 72.33%,respectively.Increasing DSY to 33.92 g/L(1.5 times)improved lactic acid productivity(QL)by~31%but did not enhance PL or SC.However,supplementing 33.92 g/L of DSY with 7.60 g/L of YE enhanced lactic acid production by~19-53%,achieving a PL of 70.11 g/L,SC of 92.33%,QL of 2.34 g/L⋅h,with a high lactic acid yield(YL/S),1.02 g/g.Scale-up fermentation in a 7.5-L fermenter demonstrated comparable results to those using 15.20 g/L of YE alone.These findings demonstrate that sweet sorghum juice supplemented with DSY and reduced YE is a promising medium for efficient lactic acid production,offering significant cost reduction potential for industrial applications while maintaining high productivity and yield.展开更多
Parkinson’s disease is characterized by synucleinopathy-associated neurodegeneration.Previous studies have shown that glucagon-like peptide-1(GLP-1)has beneficial effects in a mouse model of Parkinson’s disease indu...Parkinson’s disease is characterized by synucleinopathy-associated neurodegeneration.Previous studies have shown that glucagon-like peptide-1(GLP-1)has beneficial effects in a mouse model of Parkinson’s disease induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine.However,the effect of GLP-1 on intrinsic synuclein malfunction remains unclear.In this study,we investigated the effect of Lactococcus lactis MG1363-pMG36e-GLP-1 on parkinsonism in SncaA53T transgenic mice and explored the underlying mechanisms.Our data showed that Lactococcus lactis MG1363-pMG36e-GLP-1 inhibited dopaminergic neuronal death,reduced pathological aggregation ofα-synuclein,and decreased movement disorders in SncaA53T transgenic mice.Furthermore,Lactococcus lactis MG1363-pMG36e-GLP-1 downregulated lipopolysaccharide-related inflammation,reduced cerebral activation of microglia and astrocytes,and promoted cell survival via the GLP-1 receptor/PI3K/Akt pathway in the substantia nigra.Additionally,Lactococcus lactis MG1363-pMG36e-GLP-1 decreased serum levels of pro-inflammatory molecules including lipopolysaccharide,lipopolysaccharide binding protein,interleukin-1β,and interleukin-6.Gut histopathology and western blotting further revealed that Lactococcus lactis MG1363-pMG36e-GLP-1 increased the expression of gut integrity-related proteins and reduced lipopolysaccharide-related inflammation by reversing gut dysbiosis in SncaA53T transgenic mice.Our findings showed that the beneficial effect of Lactococcus lactis MG1363-pMG36e-GLP-1 on parkinsonism traits in SncaA53T transgenic mice is mediated by microglial polarization and the reversal of dysbiosis.Collectively,our findings suggest that Lactococcus lactis MG1363-pMG36e-GLP-1 is a promising therapeutic agent for the treatment of Parkinson’s disease.展开更多
文摘The influence of relative humidity (RH) on quasistatic current-voltage (I-V) characteristics of Bifidobacterium animalis subsp. lactis BB-12 thin layers was studied for the first time. The value of electrical conductivity in 75% RH was found to be in the order of 10-7 (ohm·cm)-1, which was 106 orders of magnitude higher than that observed in dry atmosphere. It was concluded that RH played a key role in hysteresis behavior of the measured (I-V) characteristics. FTIR measurements showed that under water moisture environment, the associated bonds between amine and carboxyl group were greatly strengthened that was the source of free charge carries after ionization. The surface charge of Bifidobacterium animalis subsp. lactis BB-12 was found to be negative by zeta potential measurements, claiming that electrons were the charge carriers.
基金supported by the Guangdong Major Project of Basic and Applied Basic Research[grant numbers 2020B0301030005].
文摘Sufu,a traditional fermented soybean curd,is prone to contamination by Bacillus cereus.In this study,133 lactic acid bacteria(LAB)strains were initially screened from spring and winter Mao-tofu samples for their ability to inhibit the growth of B.cereus ATCC 14579T.Among these strains,five Lactococcus lactis strains exhibited a good safety profile and were capable of growing in pH 4-9 and salt concentrations of 6%-8%.Antimicrobial experiments conducted on the B.cereus group from sufu factories showed that L.lactis LJL7m20 strain had the strongest inhibitory effect.Whole-genome sequencing revealed the presence of three genes associated with high osmotic stress response and eight distinct two-component systems that may contribute to the strain’s tolerance,enhancing its survival in high-salt environments.The strain was further identified as L.lactis subsp.lactis through a combination of phenotypic and genotypic analysis.Additionally,bacteriocins nisin Z and nisin A/Q were identified using the BAGEL4 and antiSMASH databases.ELISA further confirmed the strain’s ability to produce nisin.A fermentation validation study demonstrated that inoculation with the strain contributed to reduce the number of B.cereus group in sufu pehtzes.This study provides a theoretical foundation for the use of new biocontrol bacteria to improve the safety of traditional fermented soybean foods.
基金supported by the Zhongyuan Sci-Tech Innovation Leading Talents(254000510040)the National Natural Science Foun-dation of China(32172211)+2 种基金the Key Science Research Projects of Higher Education Institutions in Henan Province(21A530006)the Henan Provincial Natural Science Foundation General Program(252300421403)the Key Research and Development and Promo-tion Projects of Henan Province(232102310293).
文摘Lactic acid bacteria(LAB)are often exposed to ionizing radiation(IR)in the process of mutagenesis and food processing,and high doses of IR can cause damage and death to LAB.LlrG,a response regulator(RR)in twocomponent system(TCS),holds a significant role in enabling LAB to adapt to the environment.In our previous study,the expression of LlrG protein in Lactococcus lactis subsp.lactis IL1403(L.lactis IL1403)was significantly increased after induction by IR.To explore the IR adaptation mechanism of L.lactis IL1403 regulated by LlrG,the gene llrG in L.lactis IL1403 was overexpressed(L.lactis IL1403-llrG)and the transcriptomics and proteomics were studied.Results showed that L.lactis IL1403-llrG had significantly higher survival rate and stronger antioxidant capacity under IR conditions compared with L.lactis IL1403-p(L.lactis IL1403 contained pMG36e).Meanwhile,the transcriptomics and proteomics analyses indicated that the overexpression of llrG resulted in the enhancement of oxidation-reduction process,response to stimulus and carbohydrate metabolism and the downregulation of amino acid biosynthesis.This research provided a new perspective on understanding the adaptive mechanism of L.lactis IL1403 response to IR based on LlrG.Furthermore,L.lactis strain with IRstress tolerance characteristic could act as a reference for the application in IR sterilization of probiotic fermented dairy products.
基金supported by the grants from the project for science and technology in the Xizhang autonomous region,‘Research and development of highland probiotic resources in Shannan city’(No.QYXTCXZX-SNS.2022-2)。
文摘The target strain DB-8 in this study was isolated from naturally fermented yogurt residues in a herder’s house in Dangxiong County,Xizang.Multi-omics and genetic evolutionary analysis has been multidimensionally validated the species attribute of DB-8,revealing traits in its metabolic properties and genetic evolution in high-altitude environments.In accordance with the data obtained from the whole genome sequence and genetic evolution of DB-8,the bacterium is confirmed to be Lactobacillus delbrueckii subsp.lactis.The results of genome functional annotation demonstrated that DB-8 possesses a multitude of distinctive genes pertaining to cell wall,membrane,envelope biosynthesis,carbohydrate metabolism,and energy metabolism.Comparative genomics analysis revealed that DB-8 has 122 specific genes that support its energy metabolism,cellular repair,and biofilm systems.It is also anticipated that these genes will have exceptionally strong acid resistance.Targeted metabolic studies confirm that DB-8 produces significantly more propionic acid and isobutyric acid than other reference strains.Furthermore,based on the results of the untargeted metabolomics study,44 different metabolites were screened to create support vector machine models based on t-test-based feature screening,with an accuracy of 0.92 for the model validation set and a prediction accuracy of 100%,which marks the first successful application of machine learning to predict subspecies characterization of Lactobacillus delbrueckii.This study offers novel ideas for the precise identification between Lactobacillus delbrueckii subsp.bulgaricus and subsp.lactis,while enhancing the understanding of the fermentation characteristics of DB-8,thereby offering a scientific basis for its in-depth application in the dairy industry.
基金supported by National Key Research and Development Program of China(No.2022YFA1304103)。
文摘Bifidobacterium animalis subsp.lactis is a well-known probiotic with potential benefits for alleviating sub-health symptoms,including immune dysfunction and anxiety.Given the strain-specific nature of its probiotic effects,identifying effective strains for sub-health alleviation is crucial.In this study,we characterized 16 B animalis subsp.lactis isolates from fecal samples and probiotic sources.We assessed the genotype-phenotype correlations related to growth,carbon source utilization,and stress tolerance in vitro.Subsequently,we profiled 107 metabolites(including 28 alcohols and 17 esters)and quantified the levels of short-chain fatty acids and three other organic acids.Three B.animalis strains,GOLDGUT-BB21,WLBA7,and WLBA6,were selected and evaluated in a sleep-deprived mouse model.In vivo,WLBA3 reduced inflammation and oxidative stress by inhibiting the NLRP3inflammasome pathway and modulating gut microbiota(e.g.,Lactobacillus and Alistipes),which in turn significantly improved weight gain and fatigue resistance,attenuated cognitive function,and anxiety-like behavior.These findings provide insights into the diversity of B.animalis subsp.lactis strain resources and highlight the potential of WLBA3 as a candidate for alleviating sub-health symptoms.
基金supported by the National Key R&D Program of China(2022YFF1100100)the 111 Project of the Education Ministry of China 577(B18053)the National Center of Technology Innovation for Dairy(2022-KYGG-6).
文摘Depression is the main cause of the global mental health burden and was recently reported to be correlated with constipation[1,2].Scattered reports have demonstrated that the association between mood disorders and gastrointestinal disturbances may be related to cross-talk between the gut and the central nervous system,referred to as the gut-brain axis[3].Recent studies reported that the gut microbiome facilitates gut-brain communication,and the importance of the microbiota–gut–brain axis in the pathogenesis of depression has become appreciated[4].
基金supported by the National Natural Science Foundation of China(No.31871829,31820103010,and 32021005)the Collaborative Innovation Centre of Food Safety and Quality Control in Jiangsu Province(Jiangsu,China).
文摘Lactococcus lactis subsp.lactis is a common starter culture in the dairy industry.In this study,the key pathway of five strains of Lactococcus lactis subsp.Lactis regarding their fermentation characteristics in milk systems were studied by metabolomic approach,fermentation characterization and sensory evaluation.Strains DSCAB11M15 and DYNDL21-2,which express the cell wall proteinase PrtM/P,exhibited rapid proliferation and acidification,with significant differences in volatile and non-volatile metabolites including upregulation of flavor compounds such as ethyl butyrate and 2,3-butanedione.Additionally,DYNDL21-2,which carries theα-ketoacid decarboxylase gene,significantly increased the content of 3-methyl-butyric aldehyde,a compound that imparts a caramel-like flavor,in fermented milk.This study offers guidance for the comprehensive investigation of starter cultures with multiple approaches.
基金supported by Research Program Funding,from Research and Innovation Department,Khon Kaen University(RP68-6-FerVAAP-001),ThailandThe authors also thank Beer Thip Brewery Co.,Ltd.,Phra Nakhon Si Ayutthaya,Thailand for providing dried spent yeast(DSY).
文摘Among the low-cost nitrogen sources(dry spent yeast or DSY,rice bran,and soybean meal),DSY was identified as the most suitable supplement for lactic acid fermentation from sweet sorghum juice by Lactococcus lactis IO-1.However,lactic acid concentration(PL)using DSY was~22%lower than the control nitrogen source,yeast extract(YE).Statistical analysis using YE as a control nitrogen source revealed optimal conditions of 74.70 g/L of initial sugar and 15.20 g/L of YE,achieving a PL of 71.95 g/L and a 91.63%sugar consumption(SC).When DSY(22.61 g/L)containing an equivalent nitrogen content to the optimal YE was tested,PL and SC decreased to 55.13 g/L and 72.33%,respectively.Increasing DSY to 33.92 g/L(1.5 times)improved lactic acid productivity(QL)by~31%but did not enhance PL or SC.However,supplementing 33.92 g/L of DSY with 7.60 g/L of YE enhanced lactic acid production by~19-53%,achieving a PL of 70.11 g/L,SC of 92.33%,QL of 2.34 g/L⋅h,with a high lactic acid yield(YL/S),1.02 g/g.Scale-up fermentation in a 7.5-L fermenter demonstrated comparable results to those using 15.20 g/L of YE alone.These findings demonstrate that sweet sorghum juice supplemented with DSY and reduced YE is a promising medium for efficient lactic acid production,offering significant cost reduction potential for industrial applications while maintaining high productivity and yield.
基金supported by grants from the Jiangxi Provincial Natural Science Foundation,No.20242BAB26134(to XF)the National Natural Science Foundation of China,Nos.82060638(to TC),82060222(to XF),82460237(to XF)+1 种基金the Major Disciplines of Academic and Technical Leaders Project of Jiangxi Province,Nos.20194BCJ22032(to TC),20213BCJL22049(to XF)Science and Technology Plan of Jiangxi Health Planning Committee,No.202210390(to XF).
文摘Parkinson’s disease is characterized by synucleinopathy-associated neurodegeneration.Previous studies have shown that glucagon-like peptide-1(GLP-1)has beneficial effects in a mouse model of Parkinson’s disease induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine.However,the effect of GLP-1 on intrinsic synuclein malfunction remains unclear.In this study,we investigated the effect of Lactococcus lactis MG1363-pMG36e-GLP-1 on parkinsonism in SncaA53T transgenic mice and explored the underlying mechanisms.Our data showed that Lactococcus lactis MG1363-pMG36e-GLP-1 inhibited dopaminergic neuronal death,reduced pathological aggregation ofα-synuclein,and decreased movement disorders in SncaA53T transgenic mice.Furthermore,Lactococcus lactis MG1363-pMG36e-GLP-1 downregulated lipopolysaccharide-related inflammation,reduced cerebral activation of microglia and astrocytes,and promoted cell survival via the GLP-1 receptor/PI3K/Akt pathway in the substantia nigra.Additionally,Lactococcus lactis MG1363-pMG36e-GLP-1 decreased serum levels of pro-inflammatory molecules including lipopolysaccharide,lipopolysaccharide binding protein,interleukin-1β,and interleukin-6.Gut histopathology and western blotting further revealed that Lactococcus lactis MG1363-pMG36e-GLP-1 increased the expression of gut integrity-related proteins and reduced lipopolysaccharide-related inflammation by reversing gut dysbiosis in SncaA53T transgenic mice.Our findings showed that the beneficial effect of Lactococcus lactis MG1363-pMG36e-GLP-1 on parkinsonism traits in SncaA53T transgenic mice is mediated by microglial polarization and the reversal of dysbiosis.Collectively,our findings suggest that Lactococcus lactis MG1363-pMG36e-GLP-1 is a promising therapeutic agent for the treatment of Parkinson’s disease.
