Six lactic acid bacterial （LAB） strains were isolated from traditionally fermented Xinjiang cheese and evaluated for functional and probiotic properties and potentials as starter cultures. The isolated six LAB strai...Six lactic acid bacterial （LAB） strains were isolated from traditionally fermented Xinjiang cheese and evaluated for functional and probiotic properties and potentials as starter cultures. The isolated six LAB strains com- prised Lactobacillus rhamnosus （one strain）, Lactobacillus helveticus （one strain）, and Enterococcus hirae （four strains）. All of the six strains were tolerant to acidic and bile salt conditions. Among which, the L. rhamnosus R4 strain showed more desirable antimicrobial, auto-aggregation, and hydrophobic activity. In addition, the strain L. rhamnosus R4 exhibited the highest level of free radical scavenging activity （53.78% of 1,1-dipheny1-2-picrylhydrazyl （DPPH） free radicals and 45.79% of hydroxyl radicals）. L. rhamnosus R4 also demonstrated cholesterol and triglyceride degrada- tion by 50.97% and 28.92%, respectively. To further examine the health-promoting effects of these LAB strains on host lifespan, Caenorhabditis elegans was used as an in vivo model. Worms fed LAB as a food source had significant differences in lifespan compared to those fed Escherichia coil OP50 （as a negative control）. Feeding of L. rhamnosus R4 extended the mean lifespan of C. elegans by up to 36.1% compared to that of the control. The results suggest that the strains isolated from Xinjiang fermented dairy products have high potential as starter cultures in the cheese industry.展开更多
Several of the fungal species associated with Fuzhuan brick tea(FBT)are considered as potential probiotics,but few studies have investigated the probiotic properties of these fungi.Here,we isolated 18 fungal strains f...Several of the fungal species associated with Fuzhuan brick tea(FBT)are considered as potential probiotics,but few studies have investigated the probiotic properties of these fungi.Here,we isolated 18 fungal strains from two types of FBT and identified these strains based on internal transcribed spacer(ITS)fragment sequence similarity to reference strains(sequence similarity>98%).Of the 18 strains,10 tolerated simulated human digestive conditions for sufficient periods in vitro:pH 2-3,0.3%-0.5%(m/V)bile salts,and artificial gastrointestinal juices.We then measured the antimicrobial activity of the remaining 10 strains against 5 enteropathogenic bacteria and tested the bacteriostatic effects of the thalli and fermentation broth extracts.Of the 6 strains with strong bacteriostatic effects,we eliminated Eurotium cristatum S-9 due to its low hydrophobicity of(26.12±0.35)%.Finally,2 exhibited good adhesion abilities to human cells(>100%).Notably,2 strains can survive in vivo,because they can be isolated from C57BL/6 mice feces.Thus,2 strains,Aspergillus cristatus H-1 and A.cristatus H-5,are herein identified as promising candidate probiotic strains.It may be put forward a novel research focus on evaluating potential probiotic fungi from FBT.展开更多
Brevibacillus laterosporus has been used as a direct-fed microbial additive in chicken feed owing to its strain safety and the ability to produce broad-spectrum antimicrobial peptides.To assess the efficacy and persis...Brevibacillus laterosporus has been used as a direct-fed microbial additive in chicken feed owing to its strain safety and the ability to produce broad-spectrum antimicrobial peptides.To assess the efficacy and persistence of Brevibacillus laterosporus,it is necessary to track the supplied strains throughout the gastrointestinal tract.This study aims to evaluate the in vitro probiotic properties of Brevibacillus laterosporus S62-9 and its capacity to colonize and persist in the intestines of broiler chickens.Results indicated that the spores of Brevibacillus laterosporus S62-9 exhibited higher tolerance to the digestive condition,and higher adhesion rate to mucus and intestinal cells compared to vegetative cells.The spores remained dormant during digestion in the crop and stomach but germinate in the small intestine with a germination rate exceeding 70%.Subsequently,the whole genome of S62-9 was sequenced,and specific primers were designed and validated based on comparative genome analysis.The quantitative PCR-based method had a detection limit ranging from 2.71 to 7.71 log10 CFU/mL in pure culture and from 3.25 to 9.25 log10 CFU/g in broiler cecal content.In vivo colonization assay indicated that the Brevibacillus laterosporus S62-9 can transiently colonize the broiler cecum.In summary,our results indicated that the Brevibacillus laterosporus S62-9 spores exhibited high tolerance to the digestive tract environment,germinated in the intestine,and establish colonization in the cecum of broilers.The findings provide a theoretical basis for the future application of Brevibacillus laterosporus S62-9 in broiler farming.展开更多
Hyperuricemia(HUA)is a chronic condition resulting from abnormal purine metabolism.The consumption of foods rich in uric acid precursors significantly contributes to the worsening of HUA.The application of lactic acid...Hyperuricemia(HUA)is a chronic condition resulting from abnormal purine metabolism.The consumption of foods rich in uric acid precursors significantly contributes to the worsening of HUA.The application of lactic acid bacteria(LAB)by breaking down uric acid precursor substances in alleviating HUA has received widespread attention in recent years.This study investigated the ability of 51 LAB strains to degrade different nucleosides and purine bases.The results showed that 16 LAB strains exhibited better ability to degrade uric acid to produce precursor substances.Among these,the intracellular and extracellular metabolites of 9 LAB strains demonstrated relatively high xanthine oxidase(XOD)inhibitory activity(inhibition rates were 6.97-37.24%and 0.90-67.57%,respectively).Subsequently,the 9 LAB strains were evaluated for probiotic properties.More importantly,4 strains of Bifidobacterium animalis subsp.lactis(B.lactis HNU212,HNU329,H22B982,and H22B963)had better probiotic properties as assessed by acid tolerance,bile salt tolerance,gastrointestinal digestion,cell surface hydrophobicity,auto-aggregation,and antibiotic sensitivity.Meanwhile,B.lactis HNU329 and its cell-free culture supernatant(CFS)attenuated the inflammatory response induced by monosodium urate in RAW 264.7 cells.These findings revealed that B.lactis HNU329 can be used as probiotic in the development of fermented foods or probiotic preparations to prevent HUA.展开更多
In this study,α-amylase andα-glucosidase inhibition activities of cell-free supernatant(CFS)of 216 lactic acid bacteria were measured to screen lactic acid bacteria resources with potential hypoglycemic functions.Si...In this study,α-amylase andα-glucosidase inhibition activities of cell-free supernatant(CFS)of 216 lactic acid bacteria were measured to screen lactic acid bacteria resources with potential hypoglycemic functions.Significant inhibition activities were detected in Pediococcus acidilactici FM-Pa-JXM94,L15,GC215 and L31,and their probiotic properties were further assessed.Following the inhibitory activities onα-glucosidase andα-amylase,the viability of simulated gastric juice and adhesive ability,FM-Pa-JXM94 was screened and identified as Pediococcus acidilactici by 16S rDNA nucleotide sequencing,and the potential hypoglycemic mechanism was explored using IR-HepG2.CFS,cell-free extract(CFE)and bacterial cells of FM-Pa-JXM94 demonstrated a strong potential to induce glucose consumption,glycogen synthesis,and pyruvate kinase activity,as well as decrease phosphoenolpyruvate carboxykinase activity of IR-HepG2 cells.Additionally,RT-qPCR results showed that CFS,CFE and bacteria cells upregulated the mRNA expression of IRS1,AKT,GYS2 and PI3K genes and downregulated the mRNA expression of GSK3β,FOXO1,PEPCK and G-6-Pase genes of IRS-1/PI3K/AKT/GSK3β/GYS2 and PI3K/AKT/FOXO1/PEPCK-G6Pase signal pathways.These findings illustrate that the different FM-Pa-JXM94 derivatives could alleviate insulin resistance of IR-HepG2 cells from key enzyme activity and gene levels.This study showcases FM-Pa-JXM94 as a promising probiotic candidate for preparing functional foods and hypoglycemic function supplements.展开更多
Due to the rising global demand for natural food additives and their critical role in public health security,lactic acid bacteria(LAB)have garnered significant attention as natural biocontrol agents.This study utilize...Due to the rising global demand for natural food additives and their critical role in public health security,lactic acid bacteria(LAB)have garnered significant attention as natural biocontrol agents.This study utilized the Oxford cup method to screen LAB strains based on inhibition zone diameters against Salmonella,followed by comprehensive characterization of growth kinetics and probiotic potential.The results demonstrated that the selected strains exhibited gamma-hemolytic activity(non-pathogenic phenotype),susceptibility to seven clinically relevant antibiotics,robust environmental resilience(>85% survival under simulated gastrointestinal stress),and potent antimicrobial efficacy.Notably,Pediococcus acidilactici OE-9 cell-free supernatant(CFS)showed exceptional performance,eliminating Salmonella within 6 h at 28℃,with antibacterial effects persisting for 7 days,while also inhibiting biofilm formation on common food-contact surfaces in high-level contamination scenarios(10^(6) CFU/mL Salmonella in eggshells),treatment with OE-9 CFS resulted in a 3-log reduction in pathogen viability.Based on these findings,the P.acidilactici OE-9 strain emerges as a novel LAB strain with remarkable antibacterial and bacteriostatic properties,holding significant potential for application in food preservation.展开更多
Enterococci are an important member of lactic acid bacteria due to their presence in fermented foods,tolerance to low pH and bile salts,bile salt hydrolase(BSH)activity,reducing cholesterol,and producing bacteriocin.H...Enterococci are an important member of lactic acid bacteria due to their presence in fermented foods,tolerance to low pH and bile salts,bile salt hydrolase(BSH)activity,reducing cholesterol,and producing bacteriocin.However,probiotic and safety issues of enterococci are still debated.It is important to investigate probiotic properties and safety evaluation of these genus because they are intentionally or unintentionally present in foods.In this study,probiotic properties(tolerance to bile salts and simulated gastric juice,antimicrobial and BSH activity,cholesterol lowering potential,auto/co-aggregation,and cell surface hydrophobicity)and safety eval-uation(antibiotic resistance,virulence factor,haemolysis and DNase activity,Galleria mellonella infection model,gelatinase activity,and biofilm formation)of Enterococcus faecium(E.faecium)BH04,BH12,BH84,and BH99 isolated raw cow’s milk were determined.All strains had high tolerance to bile salts(47.70%-103.84%)and simulated gastric juice(76.80%-82.05%),and antimicrobial activity on L.monocytogenes ATCC 7644 by protein-like substances such as bacteriocin.The strains had strong BSH property and reduced cholesterol by 69.47%-95.00%.The strains were resistant only to gentamicin,kanamycin,and streptomycin and did not have hae-molysis and DNase activity.Only gelE and esp genes were detected in some strains.According to the results,it is thought that the E.faecium strains could be possible probiotic candidates.Moreover,this study is the first report on Enterococcus faecium strains isolated from raw cow’s milk,which tolerate to bile salt and simulated gastric juice,have BSH potential and antimicrobial activity by protein-like substances,and reduce cholesterol level.展开更多
The indigenous starter cultures isolated from fermented food can compete with spoilage and pathogenic bacteria and improve the flavor and organoleptic properties of products.The purposes of this work were to screen an...The indigenous starter cultures isolated from fermented food can compete with spoilage and pathogenic bacteria and improve the flavor and organoleptic properties of products.The purposes of this work were to screen and assess the safety,potential probiotic,and fermentation properties of indigenous starter cultures isolated from dry-cured ducks.The properties of indigenous starter cultures were investigated by antibiotic resistance,virulence genes,in vivo toxicity,simulated gastrointestinal,adhesion capacity to Caco-2 cells,inoculation fermentation,etc.Overall,six strains were isolated and identified,including Lactobacillus sakei D15,Weissella hellenica D20,Lactobacillus curvatus D2,Staphylococcus simulans D12,Staphylococcus equorum D19,and Staphylococcus edaphicus D17.The obtained strains showed high safety.Additionally,most strains displayed excellent probiotic properties,including tolerance to lower pH,lysozyme,bile salt,and a high survival rate of the simulated gastrointestinal phase.The adhesion ability of strain cells to Caco-2 cells was 9.22%-14.21%.And the probiotic properties of strains can be strengthened by the expression of specific enzymes.The inoculation with the isolated strains(LS-D15,LC-D2 and SS-D12)could contribute to the formation of volatile flavor compounds in samples.Overall,results demonstrated that strains possessed excellent safety and probiotic properties,and can be used as starter cultures to enhance the quality and flavor of the dry-cured duck.展开更多
This study aimed to investigate the safety and probiotic properties of Lactobacillus paraplantarum LS-5 isolated from traditional northeastern sauerkraut,and to assess the antioxidant capacity of different solvent ext...This study aimed to investigate the safety and probiotic properties of Lactobacillus paraplantarum LS-5 isolated from traditional northeastern sauerkraut,and to assess the antioxidant capacity of different solvent extracts(ethanol,water,and hot water)of L.paraplantarum LS-5-inoculated sauerkraut.L.paraplantarum LS-5 was shown to have various probiotic characteristics,such as good survival ability under artificial gastrointestinal conditions,antagonistic activity of various pathogens,non-biogenic amines,antibiotic susceptibility,and non-hemolytic.The 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulfonate(ABTS)radical scavenging activity of the L.paraplantarum LS-5-inoculated sauerkraut alcohol extract(71.13%)was significantly higher than water extract(59.59%)(p<0.05).The ferric reducing antioxidant power(FRAP)of sauerkraut alcohol extract(614.93 Troloxμmol L^(-1))exhibited a slightly stronger ability compared to water extract(388.53 Troloxμmol L^(-1))and the heated sauerkraut water extract(383.20 Troloxμmol L^(-1))at extract concentrations of 5.0 mg mL^(-1).Its 1,1-diphenyl1-2-picrylhydrazyl(DPPH)radical scavenging activity was also stronger.It was found by principal component analysis(PCA)and Pearson that the DPPH radical-scavenging activities of sauerkraut extracts were significantly correlated with the content of polyphenols and flavonoids(p<0.05).Unlike kimchi,Northeastern sauerkraut is consumed mainly by heating,so this study could contribute to understanding the antioxidant capacity of different solvent extracts of sauerkraut,and before and after heating water extracts.展开更多
In this study,high-throughput sequencing was used to analyze the microbial diversity and relative abundance of the blueberry epidermis and found that lactic acid bacteria(LAB)represent a relatively abundant group.Puta...In this study,high-throughput sequencing was used to analyze the microbial diversity and relative abundance of the blueberry epidermis and found that lactic acid bacteria(LAB)represent a relatively abundant group.Putative LAB strains were isolated and purified from the blueberry epidermis by traditional biological methods.Thirty LAB strains were identified by genotype identification,physiological and biochemical test,and 16 S rDNA sequence analysis revealed 100% sequence identity between 8 isolated strains and the representative LAB in the blueberry epidermis.Of the 8 strains,ZYN-0417(Lactobacillus rhamnosus)and ZYN-0221(Lactobacillus plantarum)showed strong tolerance in the probiotic test.Under gastric acid conditions with a pH of 2.0,the respective survival rate reached 65.71% and 68.85%.The respective survival rate reached 96.45% and 98.37% in 1.8% bile salt.After incubation in vitro gastrointestinal fluid for 240 min,the respective survival rate reached 91.00% and 86.26%.The antioxidant capacity test showed that the DPPH scavenging rate of ZYN-0417 and ZYN-0221 reached 85.45% and 87.45%,with ABTS free radical scavenging rate of 76.03% and 66.17%,OH scavenging rate of 57.30% and 46.93%,and Fe2+chelating ability of 46.34% and 43.70%,respectively.Fermentation study showed that ZYN-0417 and ZYN-0221 were capable of strong acid production with respective pH values and total acid content of 3.64 and 3.63,14.88 mg·L^(-1) and 14.85 mg·L^(-1) after 36 h of fermentation.Moreover,ZYN-0417 and ZYN-0221 showed strong extracellular protease activity(82.99 U·mL^(-1) and 95.17 U·mL^(-1),respectively).Blueberry juice fermentation showed robust growth of ZYN-0417 and ZYN-0221 and the viable bacterial number of LAB reached 13-14 log CUF·mL^(-1) at the end of fermentation.In summary,blueberry-derived LAB have good probiotic and antioxidant properties,and strong fermentation properties in low acid environments,thus showing the potential of their use for the lactobacillus fermentation of fruit and vegetables.展开更多
Hyperglycemia and diabetes are widely recognized as prevalent metabolic disorders,often associated with various complications,including hepatic and renal dysfunction as well as cardiovascular damage.Lactic acid bacter...Hyperglycemia and diabetes are widely recognized as prevalent metabolic disorders,often associated with various complications,including hepatic and renal dysfunction as well as cardiovascular damage.Lactic acid bacteria(LAB)strains have been proposed as potential agents for ameliorating hyperglycemia without causing adverse effects.In this study,we established a multi-target,comprehensive in vitro methodology to screen LAB strains with enhanced potential against hyperglycemia,using Lactobacillus rhamnosus(LGG)as a reference strain.We initially selected 43 strains isolated from the human gastrointestinal tract based on theirα-glucosidase inhibitory activity;subsequently,their capacity to inhibitα-amylase was evaluated throughα-amylase inhibition assays.Furthermore,insulin sensitization was assessed via tyrosine phosphatase 1B inhibition,along with antioxidant capabilities.To thoroughly evaluate the efficacy of LAB strains in improving abnormal glucose metabolism,we developed an insulin-resistant HepG2 cell model.Principal component analysis revealed that NCUH012072(Lacticaseibacillus paracasei),NCUH003081(Limosilactobacillus fermentum),NCUH064006(Limosilactobacillus reuteri),and two strains of NCUH001099(Lactiplantibacillus plantarum)exhibited superior hypoglycemic properties.Concurrently,these LAB strains demonstrated robust acid resistance and bile salt tolerance while showing neither hemolytic activity nor antibiotic resistance.These findings suggested that NCUH012072(Lacticaseibacillus paracasei),NCUH003081(Limosilactobacillus fermentum),and NCUH064006(Limosilactobacillus reuteri)are promising probiotic candidates for glycemic control.展开更多
[Objective] The paper was to isolate and identify probiotics in the intestine of laying hens. [Method] The intestinal probiotics in laying hens at peak period were isolated using conventional separation methods; the p...[Objective] The paper was to isolate and identify probiotics in the intestine of laying hens. [Method] The intestinal probiotics in laying hens at peak period were isolated using conventional separation methods; the physical and chemical properties of target strains and in vitro antibacterial effects were measured. Moreover, the safety test of chicks was conducted. [Result] Four strains of lactobacillus were isolated from the jejunum of laying hens, including Lactobacillus plantarum, Bacillus acidophilus, L. delbrueckii subsp. Delbrueckii and L. delbrueckii subsp. Lactis, and their inhibition zone diameters were 18.30, 16.07, 11.45, 17.26 mm, respectively. One strain of Lactobacillus, L. brevis, was isolated from the cecum, with the inhibition zone diameter of 10.26 mm. Three strains of bacillus were isolated from the cecum, including Bacillus subtilis, B. cereus and B. licheniformis, and their inhibition zone diameters were 9.25, 8.46 and 8.37 mm, respectively. Daily drinking 2 billion units of viable bacteria was the safe dosage for chicks. [Conclusion] Eight strains of probiotics had certain inhibitory effect on Escherichia coli O;, and had no toxic side effects to chicks. Lactobacillus had strong antibacterial effect on E. coli O;, while the antibacterial effect of bacillus was relatively weak.展开更多
This study aimed to screen chicken-derived Bacillus strains suitable for fermentation of Pseudostellaria heterophylla fibrous roots.Bacillus strains were isolated from cecal chyme samples of healthy chicken and fermen...This study aimed to screen chicken-derived Bacillus strains suitable for fermentation of Pseudostellaria heterophylla fibrous roots.Bacillus strains were isolated from cecal chyme samples of healthy chicken and fermented with P.heterophylla fibrous roots for re-screening.Biological characterization,safety evaluation,and identification based on morphological characteristics,physiological and biochemical properties,and molecular biological identification were carried out for the strains screened out.The results showed that five Bacillus strains X1-X5 were isolated from the cecal chyme samples in primary screening,and two elite strains X1 and X4 were obtained by re-screening.Both strains X1 and X4 had the ability to produce amylase and protease,adapt to pH value of 6-8,and tolerate bile salt of 0.1%-0.3%and simulated gastric and intestinal fluid environments.The safety evaluation results showed that the strains had no hemolytic activity,which indicated good biological safety.Strains X1 and X4 were identified as Bacillus subtilis and Bacillus licheniformis,respectively,based on the morphological characteristics,physiological and biochemical properties,and molecular biological identification.In summary,strains X1 and X4 with strong stress resistance,probiotic properties,and safety can be used as candidate probiotic strains for the fermentation of P.heterophylla fibrous roots.展开更多
Lacticaseibacillus rhamnosus Lr-CPU2205,isolated from traditional Sichuan pickled vegetables,demonstrates promising probiotic properties,as revealed through integrated genomic and phenotypic analyses.The strain exhibi...Lacticaseibacillus rhamnosus Lr-CPU2205,isolated from traditional Sichuan pickled vegetables,demonstrates promising probiotic properties,as revealed through integrated genomic and phenotypic analyses.The strain exhibited robust gastrointestinal tolerance,with 70.4%survival at pH 4.0 and 31%survival in the presence of 0.1%bile salts.It also showed significant in vitro antibacterial activity against Salmonella Typhimurium and Escherichia coli,along with potent free radical scavenging capacity against 1,1-diphenyl-2-picrylhydrazyl(DPPH)(20.47%),hydroxyl(46.74%),and superoxide anion(38.09%)radicals.Whole-genome sequencing identified a 2.96 Mbp chromosome encoding key genes involved in carbohydrate metabolism(e.g.,Carbohydrate-active enzymes(CAZymes)),stress adaptation(e.g.,nhaK,napA,bsaA),and antimicrobial peptide synthesis.In vivo studies using Caenorhabditis elegans revealed that Lr-CPU2205 enhanced resistance to S.Typhimurium infection,improved oxidative stress survival under H_(2)O_(2)challenge(50%lifespan extension),and extended normal life-span by 42.11%.Safety assessments indicated no detectable virulence factors and general antibiotic suscepti-bility,except for intrinsic resistance to co-trimoxazole and ampicillin.These findings highlight L.rhamnosus Lr-CPU2205 as a safe and multi-functional probiotic candidate suitable for application in functional foods and health-promoting formulations.展开更多
The worldwide obesity epidemic has imposed human being a huge burden and attention had been drawn to manipulating the lactic acid bacteria (LAB) to improve obesity symptoms.In this study,a more comprehensive and relia...The worldwide obesity epidemic has imposed human being a huge burden and attention had been drawn to manipulating the lactic acid bacteria (LAB) to improve obesity symptoms.In this study,a more comprehensive and reliable in vitro method was established to screen LAB with greater potential against obesity.Firstly,twenty-eight human feces-derived LAB strains were selected by assessing bile salt-acid tolerance and cholesterol lowering capacity.Subsequently,the triglyceride lowering capacity,bile salt hydrolase (BSH) activity,α-glucosidase activity inhibition capacity and Enterobacter cloacae (E.cloacae) growth inhibition capacity were tested for further evaluating the anti-obesity properties of LAB strains.Principal component analysis (PCA) of these results indicated that Limosilactobacillus reuteri (L.reuteri) NCUH003,Lactiplantibacillus plantarum (L.plantarum) NCUH046 and Limosilactobacillus fermentum (L.fermentum) NCUH068 exhibited favorable anti-obesity properties.Besides,the LAB displayed good gastrointestinal adaptability and antioxidant activity but no hemolytic activity,and they were sensitive to various antibiotics.These results indicated that L.reuteri NCUH003,L.plantarum NCUH046 and L.fermentum NCUH068 are potential for application in obesity treatment.展开更多
This study characterized Lactiplantibacillus plantarum LY-21,a strain isolated from kimchi,focusing on its pro-biotic traits and antimicrobial potential.The cell-free supernatant(CFS)exhibited excellent antibacterial ...This study characterized Lactiplantibacillus plantarum LY-21,a strain isolated from kimchi,focusing on its pro-biotic traits and antimicrobial potential.The cell-free supernatant(CFS)exhibited excellent antibacterial activity against ten Gram-positive and Gram-negative pathogens.Critically,biochemical validation through protease treatment confirmed the presence of bacteriocins,which retained antimicrobial activity after the removal of organic acids and hydrogen peroxide.Genomic analysis further identified key gene clusters responsible for the synthesis of multiple antimicrobial metabolites,including dipeptide bacteriocin clusters(plnEF),extracellular polysaccharide(EPS)gene clusters(cps2,cps3,cps4),and enzymes essential for the biosynthesis of phenyllactic acid(aminotransferase,lactate dehydrogenase)and indole-3-lactic acid(aromatic amino acid transferase,indole-lactate dehydrogenase).These compounds are speculated to possess potential synergistic effects through com-plementary mechanisms such as membrane disruption,DNA damage and metabolic inhibition,collectively enhancing the overall antibacterial efficacy.Combined with its high gastrointestinal tolerance,favorable anti-biotic susceptibility,and absence of hemolytic or biogenic amine production,these findings support the potential of L.plantarum LY-21 as a safe probiotic and a natural antimicrobial agent for therapeutic and food preservation.展开更多
Hypercholesterolemia is a great threat to humans.Bile salt hydrolase(BSH)-producing lactic acid bacteria(LAB)may alleviate it,but current screening methods are inadequate.This study aimed to establish a more comprehen...Hypercholesterolemia is a great threat to humans.Bile salt hydrolase(BSH)-producing lactic acid bacteria(LAB)may alleviate it,but current screening methods are inadequate.This study aimed to establish a more comprehensive in vitro method to screen BSH-producing LAB with greater potential for anti-hypercholesterolemia.Fortyone LAB were initially isolated from infant feces and 37 strains could produce BSH.Strains with BSH over 2 U/mg for sodium glycodeoxycholate and sodium taurodeoxycholate were used to analyse cholesterol degradation rate,hydrophobicity,self-aggregation,gastric fluid tolerance,and intestinal fluid tolerance.Based on the results of these indicators,Lactococcus lactis Y17,L.rhamnosus Q2,and L.fermentum Q11 with the top scores were considered anti-hypercholesterolemia candidates using a principal component analysis evaluation.Antioxidant and Caco-2 adhesion assays showed that these three strains exhibited excellent antioxidant ability and Caco-2 adhesion ability.Their total antioxidant capacity was above 0.99μmol/L,while the Caco-2 adhesion rate was higher than 8.22%.Safety assessments,via antibiotic susceptibility and hemolysis tests,confirmed their safety.In the HepG2 cells assay,the total cholesterol content of the Y17,Q2,and Q11 groups was reduced by 0.525 mmol/L,0.426 mmol/L,and 0.581 mmol/L,which verified the potential of the three LAB in anti-hypercholesterolemia.In addition,they could enhance cholesterol uptake and bile acid synthesis in HepG2 cells by upregulating the mRNA expression of bile acid synthase(CYP7A1 and CYP8B1)and cholesterol uptake receptors(NPC1L1 and LDLR).The results showed that the three LAB could be developed into anti-hypercholesterolemia foods with beneficial properties.展开更多
Selecting probiotic strains from maternal and infant sources,combined with processes tailored for early-life applications,may enhance probiotic efficacy.In this study,26 Bifidobacterium strains(five species)isolated f...Selecting probiotic strains from maternal and infant sources,combined with processes tailored for early-life applications,may enhance probiotic efficacy.In this study,26 Bifidobacterium strains(five species)isolated from infant and maternal feces,and breast milk were systematically assessed for physiological traits,techno-logical potential,functionality,and safety.Distinct source-and species-specific differences were observed.Breast milk-derived strains showed lower tolerance to simulated gastric fluid than those from feces.Regarding anti-biotic susceptibility,B.longum subsp.longum was sensitive to tetracycline and streptomycin but resistant to erythromycin,while B.breve showed the opposite profile.A comprehensive evaluation model integrating nine assessment parameters identified one B.breve and one B.longum subsp.longum strain with superior potential for application.Correlation analyses revealed significant relationships among physiological traits and between traits and functional genes.For instance,antibacterial activity and organic acid production showed positive correla-tions with each other,as well as with genes encoding specific virulence factors and transport proteins.These findings offer mechanistic and genomic insights for selecting probiotics tailored to early-life health.展开更多
Lactic acid bacteria(LAB)represent a category of probiotics commonly found in the gastrointestinal tracts of both humans and animals.The bacteriocins synthesized by LAB strains are believed to play a crucial role in p...Lactic acid bacteria(LAB)represent a category of probiotics commonly found in the gastrointestinal tracts of both humans and animals.The bacteriocins synthesized by LAB strains are believed to play a crucial role in promoting intestinal health.Bacteriocin ZFM216-ab,comprised of two distinct components,was purified from the cell-free supernant of Lacticaseibacillus rhamnosus ZFM216(CCTCC NO:M2020325).The molecular weights of these components were determined to be 991.58 Da and 1150.63 Da.Bacteriocin ZFM216-ab exhibits broadspectrum antibacterial activity,exhibiting minimum inhibitory concentrations(MICs)of 7.50μg/mL and 3.75μg/mL against Listeria monocytogenes and Salmonella paratyphi B,respectively,in a concentration-dependent manner.In an in vitro human intestinal microbiota model,an increase in the population of Lacticaseibacillus was observed following intervention with L.rhamnosus ZFM216.In contrast,direct intervention with Bacteriocin ZFM216-ab led to a significant enhancement of Lactobacillus,Streptococcus and Faecalibacterium abundance.In both intervention groups,a reduction in Clostridium_sensu_stricto_1 and Paraclostridium was noted.Furthermore,the metabolic levels of short-chain fatty acids(SCFAs)in fecal samples were significantly elevated,particularly acetic acid and isobutyric acid.These findings highlight the potential of L.rhamnosus ZFM216 and its bacteriocin as promising candidates for the modulation of gut microbiota homeostasis.展开更多
Limosilactobacillus fermentum JL-2 with high production of exopolysaccharide(EPS)was screened from the traditional fermented dairy product in Xinjiang district(China)in our previous work.In this study,the whole genome...Limosilactobacillus fermentum JL-2 with high production of exopolysaccharide(EPS)was screened from the traditional fermented dairy product in Xinjiang district(China)in our previous work.In this study,the whole genome of L.fermentum JL-2 was sequenced and the genomic information and function were studied to excavate its genotype,safety and probiotic properties.The safety evaluation in vitro showed that L.fermentum JL-2 was not hemolytic,sensitive to common antibiotics,and it had a weak biogenic amine production capacity.The genes related to EPS biosynthesis and their relationship with EPS production were discussed.The EPS production of L.fermentum JL-2 was 553.6 mg/L.The genome of L.fermentum JL-2 consisted of a circular 1.98 Mbp chromosome.A variety of genes related to probiotic properties such as acid tolerance,bile salt tolerance,adhesion to gut mucosa and environmental stress resistance were contained.A complete EPS gene cluster was found in the genome of L.fermentum JL-2,and the genes related to EPS biosynthesis such as epsA and epsB were found in L.fermentum JL-2.It is worth noting that EPS biosynthesis protein(gene0099)seemed to play a key role in the EPS synthesis of L.fermentum JL-2.These results revealed the potential of L.fermentum JL-2 as a probiotic at the gene level.Therefore,this study laid a theoretical foundation for further research into its potential probiotic function and its application in practice.展开更多
基金supported by the National Key Technology R&D Program of China(No.2012BAD33B08)the Zhejiang Provincial Natural Science Foundation of China(No.LY12B06006)+1 种基金the Research Program of Education Department of Zhejiang Province(No.Y201122061)the National Natural Science Foundation of China(No.20906060)
文摘Six lactic acid bacterial （LAB） strains were isolated from traditionally fermented Xinjiang cheese and evaluated for functional and probiotic properties and potentials as starter cultures. The isolated six LAB strains com- prised Lactobacillus rhamnosus （one strain）, Lactobacillus helveticus （one strain）, and Enterococcus hirae （four strains）. All of the six strains were tolerant to acidic and bile salt conditions. Among which, the L. rhamnosus R4 strain showed more desirable antimicrobial, auto-aggregation, and hydrophobic activity. In addition, the strain L. rhamnosus R4 exhibited the highest level of free radical scavenging activity （53.78% of 1,1-dipheny1-2-picrylhydrazyl （DPPH） free radicals and 45.79% of hydroxyl radicals）. L. rhamnosus R4 also demonstrated cholesterol and triglyceride degrada- tion by 50.97% and 28.92%, respectively. To further examine the health-promoting effects of these LAB strains on host lifespan, Caenorhabditis elegans was used as an in vivo model. Worms fed LAB as a food source had significant differences in lifespan compared to those fed Escherichia coil OP50 （as a negative control）. Feeding of L. rhamnosus R4 extended the mean lifespan of C. elegans by up to 36.1% compared to that of the control. The results suggest that the strains isolated from Xinjiang fermented dairy products have high potential as starter cultures in the cheese industry.
基金supported by the Shaanxi Special Project of China(2018ZDXM-NY-084)。
文摘Several of the fungal species associated with Fuzhuan brick tea(FBT)are considered as potential probiotics,but few studies have investigated the probiotic properties of these fungi.Here,we isolated 18 fungal strains from two types of FBT and identified these strains based on internal transcribed spacer(ITS)fragment sequence similarity to reference strains(sequence similarity>98%).Of the 18 strains,10 tolerated simulated human digestive conditions for sufficient periods in vitro:pH 2-3,0.3%-0.5%(m/V)bile salts,and artificial gastrointestinal juices.We then measured the antimicrobial activity of the remaining 10 strains against 5 enteropathogenic bacteria and tested the bacteriostatic effects of the thalli and fermentation broth extracts.Of the 6 strains with strong bacteriostatic effects,we eliminated Eurotium cristatum S-9 due to its low hydrophobicity of(26.12±0.35)%.Finally,2 exhibited good adhesion abilities to human cells(>100%).Notably,2 strains can survive in vivo,because they can be isolated from C57BL/6 mice feces.Thus,2 strains,Aspergillus cristatus H-1 and A.cristatus H-5,are herein identified as promising candidate probiotic strains.It may be put forward a novel research focus on evaluating potential probiotic fungi from FBT.
基金further supported by the National Natural Science Foundation of China(grant numbers 32072199).
文摘Brevibacillus laterosporus has been used as a direct-fed microbial additive in chicken feed owing to its strain safety and the ability to produce broad-spectrum antimicrobial peptides.To assess the efficacy and persistence of Brevibacillus laterosporus,it is necessary to track the supplied strains throughout the gastrointestinal tract.This study aims to evaluate the in vitro probiotic properties of Brevibacillus laterosporus S62-9 and its capacity to colonize and persist in the intestines of broiler chickens.Results indicated that the spores of Brevibacillus laterosporus S62-9 exhibited higher tolerance to the digestive condition,and higher adhesion rate to mucus and intestinal cells compared to vegetative cells.The spores remained dormant during digestion in the crop and stomach but germinate in the small intestine with a germination rate exceeding 70%.Subsequently,the whole genome of S62-9 was sequenced,and specific primers were designed and validated based on comparative genome analysis.The quantitative PCR-based method had a detection limit ranging from 2.71 to 7.71 log10 CFU/mL in pure culture and from 3.25 to 9.25 log10 CFU/g in broiler cecal content.In vivo colonization assay indicated that the Brevibacillus laterosporus S62-9 can transiently colonize the broiler cecum.In summary,our results indicated that the Brevibacillus laterosporus S62-9 spores exhibited high tolerance to the digestive tract environment,germinated in the intestine,and establish colonization in the cecum of broilers.The findings provide a theoretical basis for the future application of Brevibacillus laterosporus S62-9 in broiler farming.
基金supported by the National Natural Science Foundation of China(No.U23A20259)“Nan Hai Xin Xing”Science and Technology Innovation Talent Platform Project Funding of Hainan Province(NHXXRCXM202312).
文摘Hyperuricemia(HUA)is a chronic condition resulting from abnormal purine metabolism.The consumption of foods rich in uric acid precursors significantly contributes to the worsening of HUA.The application of lactic acid bacteria(LAB)by breaking down uric acid precursor substances in alleviating HUA has received widespread attention in recent years.This study investigated the ability of 51 LAB strains to degrade different nucleosides and purine bases.The results showed that 16 LAB strains exhibited better ability to degrade uric acid to produce precursor substances.Among these,the intracellular and extracellular metabolites of 9 LAB strains demonstrated relatively high xanthine oxidase(XOD)inhibitory activity(inhibition rates were 6.97-37.24%and 0.90-67.57%,respectively).Subsequently,the 9 LAB strains were evaluated for probiotic properties.More importantly,4 strains of Bifidobacterium animalis subsp.lactis(B.lactis HNU212,HNU329,H22B982,and H22B963)had better probiotic properties as assessed by acid tolerance,bile salt tolerance,gastrointestinal digestion,cell surface hydrophobicity,auto-aggregation,and antibiotic sensitivity.Meanwhile,B.lactis HNU329 and its cell-free culture supernatant(CFS)attenuated the inflammatory response induced by monosodium urate in RAW 264.7 cells.These findings revealed that B.lactis HNU329 can be used as probiotic in the development of fermented foods or probiotic preparations to prevent HUA.
基金supported by Exploring and Overturning Innovation Program of Jiangsu Academy of Agricultural Sciences(ZX(21)1225)Key R&D Program Project of the Autonomous Region(2023B02028-2)。
文摘In this study,α-amylase andα-glucosidase inhibition activities of cell-free supernatant(CFS)of 216 lactic acid bacteria were measured to screen lactic acid bacteria resources with potential hypoglycemic functions.Significant inhibition activities were detected in Pediococcus acidilactici FM-Pa-JXM94,L15,GC215 and L31,and their probiotic properties were further assessed.Following the inhibitory activities onα-glucosidase andα-amylase,the viability of simulated gastric juice and adhesive ability,FM-Pa-JXM94 was screened and identified as Pediococcus acidilactici by 16S rDNA nucleotide sequencing,and the potential hypoglycemic mechanism was explored using IR-HepG2.CFS,cell-free extract(CFE)and bacterial cells of FM-Pa-JXM94 demonstrated a strong potential to induce glucose consumption,glycogen synthesis,and pyruvate kinase activity,as well as decrease phosphoenolpyruvate carboxykinase activity of IR-HepG2 cells.Additionally,RT-qPCR results showed that CFS,CFE and bacteria cells upregulated the mRNA expression of IRS1,AKT,GYS2 and PI3K genes and downregulated the mRNA expression of GSK3β,FOXO1,PEPCK and G-6-Pase genes of IRS-1/PI3K/AKT/GSK3β/GYS2 and PI3K/AKT/FOXO1/PEPCK-G6Pase signal pathways.These findings illustrate that the different FM-Pa-JXM94 derivatives could alleviate insulin resistance of IR-HepG2 cells from key enzyme activity and gene levels.This study showcases FM-Pa-JXM94 as a promising probiotic candidate for preparing functional foods and hypoglycemic function supplements.
基金supported by National Key Research and Development Program of China(2023YFF1104100&2023YFD1801000)Guangdong Major Project of Basic and Applied Basic Research(2020B0301030005)the Talent Support Project of Guangdong(2021TQ06N119).
文摘Due to the rising global demand for natural food additives and their critical role in public health security,lactic acid bacteria(LAB)have garnered significant attention as natural biocontrol agents.This study utilized the Oxford cup method to screen LAB strains based on inhibition zone diameters against Salmonella,followed by comprehensive characterization of growth kinetics and probiotic potential.The results demonstrated that the selected strains exhibited gamma-hemolytic activity(non-pathogenic phenotype),susceptibility to seven clinically relevant antibiotics,robust environmental resilience(>85% survival under simulated gastrointestinal stress),and potent antimicrobial efficacy.Notably,Pediococcus acidilactici OE-9 cell-free supernatant(CFS)showed exceptional performance,eliminating Salmonella within 6 h at 28℃,with antibacterial effects persisting for 7 days,while also inhibiting biofilm formation on common food-contact surfaces in high-level contamination scenarios(10^(6) CFU/mL Salmonella in eggshells),treatment with OE-9 CFS resulted in a 3-log reduction in pathogen viability.Based on these findings,the P.acidilactici OE-9 strain emerges as a novel LAB strain with remarkable antibacterial and bacteriostatic properties,holding significant potential for application in food preservation.
文摘Enterococci are an important member of lactic acid bacteria due to their presence in fermented foods,tolerance to low pH and bile salts,bile salt hydrolase(BSH)activity,reducing cholesterol,and producing bacteriocin.However,probiotic and safety issues of enterococci are still debated.It is important to investigate probiotic properties and safety evaluation of these genus because they are intentionally or unintentionally present in foods.In this study,probiotic properties(tolerance to bile salts and simulated gastric juice,antimicrobial and BSH activity,cholesterol lowering potential,auto/co-aggregation,and cell surface hydrophobicity)and safety eval-uation(antibiotic resistance,virulence factor,haemolysis and DNase activity,Galleria mellonella infection model,gelatinase activity,and biofilm formation)of Enterococcus faecium(E.faecium)BH04,BH12,BH84,and BH99 isolated raw cow’s milk were determined.All strains had high tolerance to bile salts(47.70%-103.84%)and simulated gastric juice(76.80%-82.05%),and antimicrobial activity on L.monocytogenes ATCC 7644 by protein-like substances such as bacteriocin.The strains had strong BSH property and reduced cholesterol by 69.47%-95.00%.The strains were resistant only to gentamicin,kanamycin,and streptomycin and did not have hae-molysis and DNase activity.Only gelE and esp genes were detected in some strains.According to the results,it is thought that the E.faecium strains could be possible probiotic candidates.Moreover,this study is the first report on Enterococcus faecium strains isolated from raw cow’s milk,which tolerate to bile salt and simulated gastric juice,have BSH potential and antimicrobial activity by protein-like substances,and reduce cholesterol level.
基金supported by the Major Science and Technology Program of Anhui,China(2021d06050001)the Anhui Provincial Natural Science Foundation of China(2108085QC148)the Fundamental Research Funds for the Central Universities of China(JZ2021HGQA0242,JZ2022HGTB0263 and JZ2021HGQB0278).
文摘The indigenous starter cultures isolated from fermented food can compete with spoilage and pathogenic bacteria and improve the flavor and organoleptic properties of products.The purposes of this work were to screen and assess the safety,potential probiotic,and fermentation properties of indigenous starter cultures isolated from dry-cured ducks.The properties of indigenous starter cultures were investigated by antibiotic resistance,virulence genes,in vivo toxicity,simulated gastrointestinal,adhesion capacity to Caco-2 cells,inoculation fermentation,etc.Overall,six strains were isolated and identified,including Lactobacillus sakei D15,Weissella hellenica D20,Lactobacillus curvatus D2,Staphylococcus simulans D12,Staphylococcus equorum D19,and Staphylococcus edaphicus D17.The obtained strains showed high safety.Additionally,most strains displayed excellent probiotic properties,including tolerance to lower pH,lysozyme,bile salt,and a high survival rate of the simulated gastrointestinal phase.The adhesion ability of strain cells to Caco-2 cells was 9.22%-14.21%.And the probiotic properties of strains can be strengthened by the expression of specific enzymes.The inoculation with the isolated strains(LS-D15,LC-D2 and SS-D12)could contribute to the formation of volatile flavor compounds in samples.Overall,results demonstrated that strains possessed excellent safety and probiotic properties,and can be used as starter cultures to enhance the quality and flavor of the dry-cured duck.
基金The work was supported by Science and Technology Innovation Fund of Dalian(2022JJ13SN091)Liaoning Province Natural Science Foundation of China(2020-MZLH-39).
文摘This study aimed to investigate the safety and probiotic properties of Lactobacillus paraplantarum LS-5 isolated from traditional northeastern sauerkraut,and to assess the antioxidant capacity of different solvent extracts(ethanol,water,and hot water)of L.paraplantarum LS-5-inoculated sauerkraut.L.paraplantarum LS-5 was shown to have various probiotic characteristics,such as good survival ability under artificial gastrointestinal conditions,antagonistic activity of various pathogens,non-biogenic amines,antibiotic susceptibility,and non-hemolytic.The 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulfonate(ABTS)radical scavenging activity of the L.paraplantarum LS-5-inoculated sauerkraut alcohol extract(71.13%)was significantly higher than water extract(59.59%)(p<0.05).The ferric reducing antioxidant power(FRAP)of sauerkraut alcohol extract(614.93 Troloxμmol L^(-1))exhibited a slightly stronger ability compared to water extract(388.53 Troloxμmol L^(-1))and the heated sauerkraut water extract(383.20 Troloxμmol L^(-1))at extract concentrations of 5.0 mg mL^(-1).Its 1,1-diphenyl1-2-picrylhydrazyl(DPPH)radical scavenging activity was also stronger.It was found by principal component analysis(PCA)and Pearson that the DPPH radical-scavenging activities of sauerkraut extracts were significantly correlated with the content of polyphenols and flavonoids(p<0.05).Unlike kimchi,Northeastern sauerkraut is consumed mainly by heating,so this study could contribute to understanding the antioxidant capacity of different solvent extracts of sauerkraut,and before and after heating water extracts.
基金supported by grants from the Ministry of Fundamental Research Funds in Heilongjiang Provincial Universities(No.145109318).
文摘In this study,high-throughput sequencing was used to analyze the microbial diversity and relative abundance of the blueberry epidermis and found that lactic acid bacteria(LAB)represent a relatively abundant group.Putative LAB strains were isolated and purified from the blueberry epidermis by traditional biological methods.Thirty LAB strains were identified by genotype identification,physiological and biochemical test,and 16 S rDNA sequence analysis revealed 100% sequence identity between 8 isolated strains and the representative LAB in the blueberry epidermis.Of the 8 strains,ZYN-0417(Lactobacillus rhamnosus)and ZYN-0221(Lactobacillus plantarum)showed strong tolerance in the probiotic test.Under gastric acid conditions with a pH of 2.0,the respective survival rate reached 65.71% and 68.85%.The respective survival rate reached 96.45% and 98.37% in 1.8% bile salt.After incubation in vitro gastrointestinal fluid for 240 min,the respective survival rate reached 91.00% and 86.26%.The antioxidant capacity test showed that the DPPH scavenging rate of ZYN-0417 and ZYN-0221 reached 85.45% and 87.45%,with ABTS free radical scavenging rate of 76.03% and 66.17%,OH scavenging rate of 57.30% and 46.93%,and Fe2+chelating ability of 46.34% and 43.70%,respectively.Fermentation study showed that ZYN-0417 and ZYN-0221 were capable of strong acid production with respective pH values and total acid content of 3.64 and 3.63,14.88 mg·L^(-1) and 14.85 mg·L^(-1) after 36 h of fermentation.Moreover,ZYN-0417 and ZYN-0221 showed strong extracellular protease activity(82.99 U·mL^(-1) and 95.17 U·mL^(-1),respectively).Blueberry juice fermentation showed robust growth of ZYN-0417 and ZYN-0221 and the viable bacterial number of LAB reached 13-14 log CUF·mL^(-1) at the end of fermentation.In summary,blueberry-derived LAB have good probiotic and antioxidant properties,and strong fermentation properties in low acid environments,thus showing the potential of their use for the lactobacillus fermentation of fruit and vegetables.
基金supported by Key Research and Development Projects of Jiangxi Province(Project No.20243BCC31004)National Key Laboratory Project(20232BCD44005)+3 种基金State Key Laboratory of Food Science and Resources,ChinaNanchang University,China(Project No.SKLFZZB-202326)Agricultural key core technology research project of Jiangxi Province(Project No.JXNK202303-05)Vegetable Industry Technology System Post Expert Project of Jiangxi Province(Project No.JXARS-06).
文摘Hyperglycemia and diabetes are widely recognized as prevalent metabolic disorders,often associated with various complications,including hepatic and renal dysfunction as well as cardiovascular damage.Lactic acid bacteria(LAB)strains have been proposed as potential agents for ameliorating hyperglycemia without causing adverse effects.In this study,we established a multi-target,comprehensive in vitro methodology to screen LAB strains with enhanced potential against hyperglycemia,using Lactobacillus rhamnosus(LGG)as a reference strain.We initially selected 43 strains isolated from the human gastrointestinal tract based on theirα-glucosidase inhibitory activity;subsequently,their capacity to inhibitα-amylase was evaluated throughα-amylase inhibition assays.Furthermore,insulin sensitization was assessed via tyrosine phosphatase 1B inhibition,along with antioxidant capabilities.To thoroughly evaluate the efficacy of LAB strains in improving abnormal glucose metabolism,we developed an insulin-resistant HepG2 cell model.Principal component analysis revealed that NCUH012072(Lacticaseibacillus paracasei),NCUH003081(Limosilactobacillus fermentum),NCUH064006(Limosilactobacillus reuteri),and two strains of NCUH001099(Lactiplantibacillus plantarum)exhibited superior hypoglycemic properties.Concurrently,these LAB strains demonstrated robust acid resistance and bile salt tolerance while showing neither hemolytic activity nor antibiotic resistance.These findings suggested that NCUH012072(Lacticaseibacillus paracasei),NCUH003081(Limosilactobacillus fermentum),and NCUH064006(Limosilactobacillus reuteri)are promising probiotic candidates for glycemic control.
文摘[Objective] The paper was to isolate and identify probiotics in the intestine of laying hens. [Method] The intestinal probiotics in laying hens at peak period were isolated using conventional separation methods; the physical and chemical properties of target strains and in vitro antibacterial effects were measured. Moreover, the safety test of chicks was conducted. [Result] Four strains of lactobacillus were isolated from the jejunum of laying hens, including Lactobacillus plantarum, Bacillus acidophilus, L. delbrueckii subsp. Delbrueckii and L. delbrueckii subsp. Lactis, and their inhibition zone diameters were 18.30, 16.07, 11.45, 17.26 mm, respectively. One strain of Lactobacillus, L. brevis, was isolated from the cecum, with the inhibition zone diameter of 10.26 mm. Three strains of bacillus were isolated from the cecum, including Bacillus subtilis, B. cereus and B. licheniformis, and their inhibition zone diameters were 9.25, 8.46 and 8.37 mm, respectively. Daily drinking 2 billion units of viable bacteria was the safe dosage for chicks. [Conclusion] Eight strains of probiotics had certain inhibitory effect on Escherichia coli O;, and had no toxic side effects to chicks. Lactobacillus had strong antibacterial effect on E. coli O;, while the antibacterial effect of bacillus was relatively weak.
文摘This study aimed to screen chicken-derived Bacillus strains suitable for fermentation of Pseudostellaria heterophylla fibrous roots.Bacillus strains were isolated from cecal chyme samples of healthy chicken and fermented with P.heterophylla fibrous roots for re-screening.Biological characterization,safety evaluation,and identification based on morphological characteristics,physiological and biochemical properties,and molecular biological identification were carried out for the strains screened out.The results showed that five Bacillus strains X1-X5 were isolated from the cecal chyme samples in primary screening,and two elite strains X1 and X4 were obtained by re-screening.Both strains X1 and X4 had the ability to produce amylase and protease,adapt to pH value of 6-8,and tolerate bile salt of 0.1%-0.3%and simulated gastric and intestinal fluid environments.The safety evaluation results showed that the strains had no hemolytic activity,which indicated good biological safety.Strains X1 and X4 were identified as Bacillus subtilis and Bacillus licheniformis,respectively,based on the morphological characteristics,physiological and biochemical properties,and molecular biological identification.In summary,strains X1 and X4 with strong stress resistance,probiotic properties,and safety can be used as candidate probiotic strains for the fermentation of P.heterophylla fibrous roots.
基金funded by Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘Lacticaseibacillus rhamnosus Lr-CPU2205,isolated from traditional Sichuan pickled vegetables,demonstrates promising probiotic properties,as revealed through integrated genomic and phenotypic analyses.The strain exhibited robust gastrointestinal tolerance,with 70.4%survival at pH 4.0 and 31%survival in the presence of 0.1%bile salts.It also showed significant in vitro antibacterial activity against Salmonella Typhimurium and Escherichia coli,along with potent free radical scavenging capacity against 1,1-diphenyl-2-picrylhydrazyl(DPPH)(20.47%),hydroxyl(46.74%),and superoxide anion(38.09%)radicals.Whole-genome sequencing identified a 2.96 Mbp chromosome encoding key genes involved in carbohydrate metabolism(e.g.,Carbohydrate-active enzymes(CAZymes)),stress adaptation(e.g.,nhaK,napA,bsaA),and antimicrobial peptide synthesis.In vivo studies using Caenorhabditis elegans revealed that Lr-CPU2205 enhanced resistance to S.Typhimurium infection,improved oxidative stress survival under H_(2)O_(2)challenge(50%lifespan extension),and extended normal life-span by 42.11%.Safety assessments indicated no detectable virulence factors and general antibiotic suscepti-bility,except for intrinsic resistance to co-trimoxazole and ampicillin.These findings highlight L.rhamnosus Lr-CPU2205 as a safe and multi-functional probiotic candidate suitable for application in functional foods and health-promoting formulations.
基金supported by National Natural Science Foundation of China(Project No.32160547)Central Government Guide Local Special Fund Project(Project No.20212ZDD02008)+2 种基金Vegetable Industry Technology System Post Expert Project of Jiangxi Province(Project No.JXARS-06)State Key Laboratory of Food Science and Technology Nanchang University(Project No.SKLF-ZZA-201910)State Key Laboratory of Food Science and Technology Nanchang University(Project No.SKLF-ZZB-202132).
文摘The worldwide obesity epidemic has imposed human being a huge burden and attention had been drawn to manipulating the lactic acid bacteria (LAB) to improve obesity symptoms.In this study,a more comprehensive and reliable in vitro method was established to screen LAB with greater potential against obesity.Firstly,twenty-eight human feces-derived LAB strains were selected by assessing bile salt-acid tolerance and cholesterol lowering capacity.Subsequently,the triglyceride lowering capacity,bile salt hydrolase (BSH) activity,α-glucosidase activity inhibition capacity and Enterobacter cloacae (E.cloacae) growth inhibition capacity were tested for further evaluating the anti-obesity properties of LAB strains.Principal component analysis (PCA) of these results indicated that Limosilactobacillus reuteri (L.reuteri) NCUH003,Lactiplantibacillus plantarum (L.plantarum) NCUH046 and Limosilactobacillus fermentum (L.fermentum) NCUH068 exhibited favorable anti-obesity properties.Besides,the LAB displayed good gastrointestinal adaptability and antioxidant activity but no hemolytic activity,and they were sensitive to various antibiotics.These results indicated that L.reuteri NCUH003,L.plantarum NCUH046 and L.fermentum NCUH068 are potential for application in obesity treatment.
基金funded by National Key Research and Development Program of China(2023YFD1801000).
文摘This study characterized Lactiplantibacillus plantarum LY-21,a strain isolated from kimchi,focusing on its pro-biotic traits and antimicrobial potential.The cell-free supernatant(CFS)exhibited excellent antibacterial activity against ten Gram-positive and Gram-negative pathogens.Critically,biochemical validation through protease treatment confirmed the presence of bacteriocins,which retained antimicrobial activity after the removal of organic acids and hydrogen peroxide.Genomic analysis further identified key gene clusters responsible for the synthesis of multiple antimicrobial metabolites,including dipeptide bacteriocin clusters(plnEF),extracellular polysaccharide(EPS)gene clusters(cps2,cps3,cps4),and enzymes essential for the biosynthesis of phenyllactic acid(aminotransferase,lactate dehydrogenase)and indole-3-lactic acid(aromatic amino acid transferase,indole-lactate dehydrogenase).These compounds are speculated to possess potential synergistic effects through com-plementary mechanisms such as membrane disruption,DNA damage and metabolic inhibition,collectively enhancing the overall antibacterial efficacy.Combined with its high gastrointestinal tolerance,favorable anti-biotic susceptibility,and absence of hemolytic or biogenic amine production,these findings support the potential of L.plantarum LY-21 as a safe probiotic and a natural antimicrobial agent for therapeutic and food preservation.
基金Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX23_1892)A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)are gratefully acknowledged.
文摘Hypercholesterolemia is a great threat to humans.Bile salt hydrolase(BSH)-producing lactic acid bacteria(LAB)may alleviate it,but current screening methods are inadequate.This study aimed to establish a more comprehensive in vitro method to screen BSH-producing LAB with greater potential for anti-hypercholesterolemia.Fortyone LAB were initially isolated from infant feces and 37 strains could produce BSH.Strains with BSH over 2 U/mg for sodium glycodeoxycholate and sodium taurodeoxycholate were used to analyse cholesterol degradation rate,hydrophobicity,self-aggregation,gastric fluid tolerance,and intestinal fluid tolerance.Based on the results of these indicators,Lactococcus lactis Y17,L.rhamnosus Q2,and L.fermentum Q11 with the top scores were considered anti-hypercholesterolemia candidates using a principal component analysis evaluation.Antioxidant and Caco-2 adhesion assays showed that these three strains exhibited excellent antioxidant ability and Caco-2 adhesion ability.Their total antioxidant capacity was above 0.99μmol/L,while the Caco-2 adhesion rate was higher than 8.22%.Safety assessments,via antibiotic susceptibility and hemolysis tests,confirmed their safety.In the HepG2 cells assay,the total cholesterol content of the Y17,Q2,and Q11 groups was reduced by 0.525 mmol/L,0.426 mmol/L,and 0.581 mmol/L,which verified the potential of the three LAB in anti-hypercholesterolemia.In addition,they could enhance cholesterol uptake and bile acid synthesis in HepG2 cells by upregulating the mRNA expression of bile acid synthase(CYP7A1 and CYP8B1)and cholesterol uptake receptors(NPC1L1 and LDLR).The results showed that the three LAB could be developed into anti-hypercholesterolemia foods with beneficial properties.
基金supported by the National Key Technologies Research and Development Program[No.2022YFD2100703]the National Natural Science Foundation of China[No.32021005 and 32122067]+1 种基金supported by the Fundamental Research Funds for the Central Universities JUSRP622013Collaborative innovation center of food safety and quality control in Jiangsu Province.
文摘Selecting probiotic strains from maternal and infant sources,combined with processes tailored for early-life applications,may enhance probiotic efficacy.In this study,26 Bifidobacterium strains(five species)isolated from infant and maternal feces,and breast milk were systematically assessed for physiological traits,techno-logical potential,functionality,and safety.Distinct source-and species-specific differences were observed.Breast milk-derived strains showed lower tolerance to simulated gastric fluid than those from feces.Regarding anti-biotic susceptibility,B.longum subsp.longum was sensitive to tetracycline and streptomycin but resistant to erythromycin,while B.breve showed the opposite profile.A comprehensive evaluation model integrating nine assessment parameters identified one B.breve and one B.longum subsp.longum strain with superior potential for application.Correlation analyses revealed significant relationships among physiological traits and between traits and functional genes.For instance,antibacterial activity and organic acid production showed positive correla-tions with each other,as well as with genes encoding specific virulence factors and transport proteins.These findings offer mechanistic and genomic insights for selecting probiotics tailored to early-life health.
基金funded by the National Natural Science Foundation of China(grant numbers U20A2066)the Key Project of Zhejiang Gongshang University“Digital+”Discipline Construction(grant numbers SZJ2022A006).
文摘Lactic acid bacteria(LAB)represent a category of probiotics commonly found in the gastrointestinal tracts of both humans and animals.The bacteriocins synthesized by LAB strains are believed to play a crucial role in promoting intestinal health.Bacteriocin ZFM216-ab,comprised of two distinct components,was purified from the cell-free supernant of Lacticaseibacillus rhamnosus ZFM216(CCTCC NO:M2020325).The molecular weights of these components were determined to be 991.58 Da and 1150.63 Da.Bacteriocin ZFM216-ab exhibits broadspectrum antibacterial activity,exhibiting minimum inhibitory concentrations(MICs)of 7.50μg/mL and 3.75μg/mL against Listeria monocytogenes and Salmonella paratyphi B,respectively,in a concentration-dependent manner.In an in vitro human intestinal microbiota model,an increase in the population of Lacticaseibacillus was observed following intervention with L.rhamnosus ZFM216.In contrast,direct intervention with Bacteriocin ZFM216-ab led to a significant enhancement of Lactobacillus,Streptococcus and Faecalibacterium abundance.In both intervention groups,a reduction in Clostridium_sensu_stricto_1 and Paraclostridium was noted.Furthermore,the metabolic levels of short-chain fatty acids(SCFAs)in fecal samples were significantly elevated,particularly acetic acid and isobutyric acid.These findings highlight the potential of L.rhamnosus ZFM216 and its bacteriocin as promising candidates for the modulation of gut microbiota homeostasis.
基金funded by National Key R&D Program of China(2022YFD2100701)the Liaoning Provincial Department of Education Funding for Basic Scientific Research Project in University,China(LJKZZ20220062).
文摘Limosilactobacillus fermentum JL-2 with high production of exopolysaccharide(EPS)was screened from the traditional fermented dairy product in Xinjiang district(China)in our previous work.In this study,the whole genome of L.fermentum JL-2 was sequenced and the genomic information and function were studied to excavate its genotype,safety and probiotic properties.The safety evaluation in vitro showed that L.fermentum JL-2 was not hemolytic,sensitive to common antibiotics,and it had a weak biogenic amine production capacity.The genes related to EPS biosynthesis and their relationship with EPS production were discussed.The EPS production of L.fermentum JL-2 was 553.6 mg/L.The genome of L.fermentum JL-2 consisted of a circular 1.98 Mbp chromosome.A variety of genes related to probiotic properties such as acid tolerance,bile salt tolerance,adhesion to gut mucosa and environmental stress resistance were contained.A complete EPS gene cluster was found in the genome of L.fermentum JL-2,and the genes related to EPS biosynthesis such as epsA and epsB were found in L.fermentum JL-2.It is worth noting that EPS biosynthesis protein(gene0099)seemed to play a key role in the EPS synthesis of L.fermentum JL-2.These results revealed the potential of L.fermentum JL-2 as a probiotic at the gene level.Therefore,this study laid a theoretical foundation for further research into its potential probiotic function and its application in practice.
