Bifidobacterium longum subsp.infantis and Bifidobacterium adolescentis play important roles in the guts of infants and adolescents,respectively.In this study,using a neonatal rat model,we compared the protective effec...Bifidobacterium longum subsp.infantis and Bifidobacterium adolescentis play important roles in the guts of infants and adolescents,respectively.In this study,using a neonatal rat model,we compared the protective effects of these 2 bifidobacterial species against Salmonella infection.The results demonstrated that B.longum subsp.infantis was more effective than B.adolescentis in alleviating the severity of infection in newborn rats exposed to Salmonella enterica serovar Typhimurium strain SL1344.B.longum subsp.infantis attenuated intestinal inflammation and mucosal damage induced by Salmonella infection,as well as protecting intestinal nerves and intestinal barrier function through TLR4/My D88 signalling.B.longum subsp.infantis also displayed the potential to modulate gut metabolites by promoting the biosynthesis of unsaturated fatty acids(arachidonic acid,eicosapentaenoic acid andα-linolenic acid)and purine metabolism(guanine,adenine,inosine and adenosine),thereby regulating metabolic disturbances.Additionally,the benefits of B.longum subsp.infantis were also observed in the liver,spleen and brain,improving nerve reflexes and suppressing hepatosplenomegaly.Overall,these findings provide novel insights into the prevention and treatment of gutrelated diseases in newborns,highlighting the potentially significant role of B.longum subsp.infantis in clinical applications.展开更多
Bifidobacterium longum subsp.infantis is a commensal bacterium that predominates in the infant gut,playing a critical role in both preventing foreign infections and facilitating immune development.This study aimed to ...Bifidobacterium longum subsp.infantis is a commensal bacterium that predominates in the infant gut,playing a critical role in both preventing foreign infections and facilitating immune development.This study aimed to explore the effects of B.longum subsp.infantis supplementation on interferon-beta(IFN-β)secretion and intestinal barrier improvement in growing mice.Female and male mice were orally administered either saline or B.longum subsp.infantis CCFM1269 or I5TI(1×10^(9) CFU/mice per day,n=8)from 1-week-age until 3-,4-,and 5-week-age.RNA sequencing analysis revealed that CCFM1269 exhibited potential antiviral capacity through increasing 2'-5'oligoadenylate synthetase(OAS).Additionally,CCFM1269 supplementation significantly increased colonic IFN-β levels which combined with OAS in 3-week-old female and male mice by activating the TLR4-TRIF-dependent signaling pathway.However,this effect was not observed in 4-and 5-week-old mice.Furthermore,both CCFM1269 were found to modulate the gut microbiota composition and enhance the intestinal barrier function in 3-,4-,and 5-week-old mice.In summary,the results of this study suggested that B.longum subsp.infantis CCFM1269 promoting intestinal barrier and releasing IFN-β in growing mice was in a strain-specific and time-dependent manner.展开更多
Objective： To construct Bifidobacterium Infantis/CD targeting gene therapy system. Methods： CD gene was amplified from E. Coli K12λ using PCR method, pGEX-1LamdaT plasmid and CD gene were digested with dual restric...Objective： To construct Bifidobacterium Infantis/CD targeting gene therapy system. Methods： CD gene was amplified from E. Coli K12λ using PCR method, pGEX-1LamdaT plasmid and CD gene were digested with dual restriction endonucleas of EcoR Ⅰ and BamH Ⅰ and two segments of 4.9 kb and 1.3 kb were obtained. T4 DNA ligase was added to these two segments to make a recombinant CD/pGEX-1LamdaT plasmid. Then the recombinant plasmid was transfected into Bifidobacterium Infantis by electroporation. The recombinant plasmid was extracted from the positively transfected Bifidobacterium Infantis and digested with dual restriction endonucleases. Then the size of digested fragments was detected and sequencing of the gene segment inserted in extracted recombinant plasmid was performed according to the method of Sanger dideoxynucleotide triphosphate chain termination. Results： 6.2 kb recombinant plasmid was obtained from the positively transfected bacterial colony of Bifidobacterium Infantis. After being digested with dual restriction endonucleases, two segments of approximate 4.9 kb and 1.3 kb were gained from the extracted recombinant plasmid, which were equal to the size of pGEX-1LamdaT plasmid and CD gene, respectively. The full length and sequence of nucleotide acid of the inserted gene in extracted recombinant plasmid was completely identical to the CD gene. Conclusion： The foreign gene, CD gene was correctly inserted into pGEX-1LambdaT plasmid and transferred into Bifidobacterium Infantis. Bifidobacterium Infantis/CD targeting gene therapy system was successfully constructed.展开更多
AIM To determine whether oral administration of Bifidobacterium infantis CGMCC313-2(B.infantis CGMCC313-2)inhibits allergen-induced airway inflammation and food allergies in a mouse model.METHODS Ovalbumin(OVA)-induce...AIM To determine whether oral administration of Bifidobacterium infantis CGMCC313-2(B.infantis CGMCC313-2)inhibits allergen-induced airway inflammation and food allergies in a mouse model.METHODS Ovalbumin(OVA)-induced allergic asthma and b-lactoglobulin-induced food allergy mouse models were used in this study.Following oral administration of B.infantis CGMCC313-2 during or after allergen sensitization,histopathologic changes in the lung and intestine were evaluated by hematoxylin and eosin(HE)staining.In the allergic asthma mouse model,we evaluated the proportion of lung-infiltrating inflammatory cells.OVAspecific IgE and IgG1 levels in serum and cytokine levels in bronchoalveolar lavage fluid(BALF)were also assessed.In the food allergy mouse model,the levels of total Ig E and cytokines in serum were measured.RESULTS Oral administration of B.infantis CGMCC313-2 during or after allergen sensitization suppressed allergic inflammation in lung and intestinal tissues,while the proportion of infiltrating inflammatory cells was significantly decreased in the BALF of allergic asthma mice.Moreover,B.infantis CGMCC313-2 decreased the serum levels of total Ig E in food allergy mice,and reductions in IgE and IgG1 were also observed in OVA-induced allergic asthma mice.The expression of interleukin-4(IL-4)and IL-13 in both serum and BALF was suppressed following the administration of B.infantis CGMCC313-2,while an effect on serum IL-10 levels was not observed.CONCLUSION B.infantis CGMCC313-2 inhibits the secretion of allergen-induced IgE,IL-4 and IL-13,and attenuates allergic inflammation.展开更多
BACKGROUND Inflammatory bowel disease(IBD)is caused by an abnormal immune response.Programmed cell death 1(PD-1)is an immunostimulatory molecule,which interacts with PD ligand(PD-L1)playing a prime important role amon...BACKGROUND Inflammatory bowel disease(IBD)is caused by an abnormal immune response.Programmed cell death 1(PD-1)is an immunostimulatory molecule,which interacts with PD ligand(PD-L1)playing a prime important role among autoimmune diseases.Bifidobacterium infantis(B.infantis)can promote the differentiation of CD(cluster of differentiation)4^(+)T cells into regulatory T cells(Tregs).Tregs participate in the development of IBD and may be related to disease activity.B.infantis amplify the expression level of PD-1,PD-L1 and Tregs’nuclear transcription factor forkhead box protein 3(Foxp3).But the mechanism of B.infantis on PD-1/PD-L1 signaling remains unclear.AIM To explore the mechanism of B.infantis regulating the immune response in IBD.METHODS Forty-eight-week-old BALB/c mice were randomly divided into five groups:The control group,dextran sulphate sodium(DSS)model group,DSS+B.infantis group,DSS+B.infantis+anti-PD-L1 group,and DSS+anti-PD-L1 group.The control group mice were given drinking water freely,the other four groups were given drinking water containing 5%DSS freely.The control group,DSS model group,and DSS+anti-PD-L1 group were given normal saline(NS)400μL daily by gastric lavage,and the DSS+B.infantis group and DSS+B.infantis+anti-PDL1 group were given NS and 1×109 colony-forming unit of B.infantis daily by gastric lavage.The DSS+B.infantis+anti-PD-L1 group and DSS+anti-PD-L1 group were given 200μg of PD-L1 blocker intraperitoneally at days 0,3,5,and 7;the control group,DSS+anti-PD-L1 group,and DSS+B.infantis group were given an intraperitoneal injection of an equal volume of phosphate buffered saline(PBS).Changes in PD-L1,PD-1,Foxp3,interleukin(IL)-10,and transforming growth factorβ(TGF-β)1 protein and gene expression were observed.Flow cytometry was used to observe changes in CD4^(+),CD25^(+),Foxp3^(+)cell numbers in the blood and spleen.RESULTS Compared to the control group,the expression of PD-1,Foxp3,IL-10,and TGF-β1 was significantly decreased in the intestinal tract of the DSS mice(P<0.05).Compared to the control group,the proportion of CD4^(+),CD25^(+),Foxp3^(+)cells in spleen and blood of DSS group was visibly katabatic(P<0.05).B.infantis upgraded the express of PD-L1,PD-1,Foxp3,IL-10,and TGF-β1(P<0.05)and increased the proportion of CD4^(+),CD25^(+),Foxp3^(+)cells both in spleen and blood(P<0.05).After blocking PD-L1,the increase in Foxp3,IL-10,and TGF-β1 protein and gene by B.infantis was inhibited(P<0.05),and the proliferation of CD4^(+),CD25^(+),Foxp3^(+)cells in the spleen and blood was also inhibited(P<0.05).After blocking PD-L1,the messenger ribonucleic acid and protein expression of PD-1 were invariant.CONCLUSION It is potential that B.infantis boost the proliferation of CD4^(+),CD25^(+),Foxp3^(+)T cells in both spleen and blood,as well as the expression of Foxp3 in the intestinal tract by activating the PD-1/PD-L1 pathway.展开更多
Objective:We recombine the suicide gene CD,UPRT into plasmid pTRKH2 and clone the recombinant dual suicide gene therapy system into tumor-hypoxia-targeting vector Bifidobacterium infantis and characterize its function...Objective:We recombine the suicide gene CD,UPRT into plasmid pTRKH2 and clone the recombinant dual suicide gene therapy system into tumor-hypoxia-targeting vector Bifidobacterium infantis and characterize its function.Methods:CD gene,UPRT gene and lactic acid bacteria expression plasmid pTRKH2 were digested by restriction endonuclease BamH I and Sal I,and constructed recombinant plasmids pTRKH2/CD and pTRKH2/UPRT in E.coli.The recombinant plasmids were then transfected into Bifidobacterium Infantis by electroporation.Identification of pTRKH2/CD and pTRKH2/UPRT was processed by dual restriction endonuclease digesting and sequencing.RT-PCR and SDS-PAGE were used to examine the expression of CD and UPRT genes at RNA and protein levels.The killing effects on Melanoma B16-F10 cells by pTRKH2/CD and pTRKH2/UPRT suicide gene therapy system with 5-FC were examined by MTT assay.Results:The CD gene and UPRT gene was successfully recombined into lactic acid bacteria expression plasmid pTRKH2.After dual endonuclease digestion of plasmid purified from the positively transfected E.coli,two fragments of 6.9 Kb and 1.3 Kb were found for CD gene and two fragments of 6.9 Kb and 620 bp were found for UPRT gene.The sequencing of CD gene and UPRT gene proved consistent sequences with Genebank published data.A fragment of 1.3 Kb for CD gene and fragment of 620 bp for UPRT gene was found in recombinant Bifidobacterium by RT-PCR.A 52 KDa protein for CD gene was identified in whole-cell protein of recombinant Bifidobacterium and a 26 KDa protein for UPRT gene was identified in supernatant fluid of recombinant Bifidobacterium.The survival rate of tumor cells treated by extracts from culture of recombinant Bifidobacterium with 5-FC showed a strong killing effects of pTRKH2/CD and pTRKH2/UPRT dual suicide gene therapy system on Melanoma B16-F10 cells.Conclusion:CD gene and UPRT gene are successfully inserted into pTRKH2 and transfected into tumor-hypoxia-targeting vector Bifidobacterium Infantis.This dual suicide gene therapy system shows a high efficiency for tumor cells killing.展开更多
Bifidobacterium longum subsp.infantis(B.infantis)is the most active consumer of human milk oligosaccharides(HMOs),which can promote the development and maturation of the infant’s intestinal immune system.In this stud...Bifidobacterium longum subsp.infantis(B.infantis)is the most active consumer of human milk oligosaccharides(HMOs),which can promote the development and maturation of the infant’s intestinal immune system.In this study,we collected information on B.infantis isolated from human feces in the NCBI database to analyze their whole genome.We found that the whole genome of the tested strains and the functional genes utilizing the HMOs showed geographical clustering.Comparison of the genes encodingα-L-fucosidase between B.infantis H11 and BINF revealed that strain H11 had moreα-L-fucosidase genes,and further heterologous expression ofα-Lfucosidase showed that only the glycoside hydrolase(GH)95 family could hydrolyze 2’-fucosyllactose(2’-FL).At the same time,FUC95A(derived from strain H11)was more efficient in catalyzing 2’-FL than FUC95B(derived from strain BINF).In addition,metabolites in the 2’-FL fermentation supernatants were analyzed based on untargeted metabolomics,and it was found that strain H11 could utilize 2’-FL to produce more beneficial metabolites compared to strain BINF.In conclusion,we hypothesized that the enhancement ofα-L-fucosidase activity of B.infantis is one of the essential requirements to improve the utilization of 2’-FL and increase the contents of beneficial metabolites to perform the probiotic function.展开更多
The early life period is a critical phase for the colonization of initial gut microbes in infants,during which the immune system develops and matures.These processes have long-lasting implications that may extend into...The early life period is a critical phase for the colonization of initial gut microbes in infants,during which the immune system develops and matures.These processes have long-lasting implications that may extend into adolescence and even adulthood.Bifidobacterium longum subsp.infantis,recognized as an ideal probiotic during infancy,has the potential to modulate intestinal immunity and mitigate immune-mediated diseases.This research explored the potential of various B.longum subsp.infantis strains to modulate the balance between T helper(Th)1 and Th2 responses,immune cell populations,Immunoglobulin A(IgA),and the related genes expression in mice.Notably,B.longum subsp.infantis FHNFQ4M11 and CCFM1269 demonstrated more robust regulatory capabilities.These two strains,which exhibited higher ILA production,activated the aryl hydrocarbon receptor(AHR)signaling pathway,upregulated the levels of galectin-1(Gal-1)and galectin-3(Gal-3),and modulated Th1/Th2 differentiation markers in the colon.Additionally,these strains significantly elevated IgA concentrations in both serum and colon and modulated the gut microbiota composition.These findings underscored the potential of specific B.longum subsp.infantis strains as targeted probiotic interventions in early life,providing a promising strategy for promoting immune homeostasis and gut health in infants.展开更多
Human milk oligosaccharides(HMOs)are considered the“golden ingredients”of human milk,and Bifidobacte-rium longum subsp.infantis(B.infantis)is not only indigenous probiotics of the infant gut,but also efficiently uti...Human milk oligosaccharides(HMOs)are considered the“golden ingredients”of human milk,and Bifidobacte-rium longum subsp.infantis(B.infantis)is not only indigenous probiotics of the infant gut,but also efficiently utilizes HMOs.The aim of this study was to investigate the potential manners in which B.infantis interacts with HMOs to promote intestinal health.We found that all strains of B.infantis tested had varying degrees of pro-tective effects on the cellular barrier,with B.infantis H11 being the most effective.The whole genome results of strain H11 revealed that it was enriched in genes related to HMOs consumption,and it could efficiently utilize HMOs,especially fully utilizing 2′-FL,3-FL,and DFL,utilizing about 60%of 3′-SL and 6′-SL,while the utilization of LNnT was lowest.By performing untargeted metabolomics analyses on the fermentation supernatant of strain H11 that utilized HMOs or lactose as a carbon source,it was found that strain H11 could utilize both HMOs and lactose to produce indole-3-lactic acid,indoleacetic acid,and other substances with potential probiotic functions.Furthermore,the tryptophan metabolic pathway was enriched with a variety of significantly different metabo-lites and had a large impact on the metabolic process,especially the serotonin pathway branch.In the fermentation supernatant of strain H11 utilizing HMOs as a carbon source,there was a significant increase in the levels of beneficial metabolites in the serotonin pathway.This may be one of the essential manners for the utilization of HMOs by strain H11 to exert probiotic potential.展开更多
Although all strains of Bifidobacterium longum subsp.infantis(B.infantis)can utilize 2′-fucosyllactose(2′-FL)as a carbon source,they exhibit notable strain-level differences in utilization efficiency and genetic mec...Although all strains of Bifidobacterium longum subsp.infantis(B.infantis)can utilize 2′-fucosyllactose(2′-FL)as a carbon source,they exhibit notable strain-level differences in utilization efficiency and genetic mechanisms.To investigate these intra-subspecific variations,we compared 2′-FL metabolism in B.infantis Y46 and the type strain B.infantis ATCC 15697 using phenotypic assays and whole-genome sequencing.Both strains were able to grow on 2′-FL as the sole carbon source,although Y46 demonstrated markedly higher growth and metabolic activity than ATCC 15697.Genomic analysis revealed Y46 has more carbohydrate metabolism genes,including 10 carbohydrate-active enzyme(CAZyme)genes absent in ATCC 15697.Despite lacking the 2′-FL transporter gene FL1_SBP,Y46 showed significantly upregulated expression of FL2_SBP,another 2′-FL transporters,and enhanced 2′-FL metabolism,suggesting an adaptive mechanism that compensates for FL1_SBP loss.These findings highlight the metabolic flexibility and ecological adaptability of Y46 and provide insight into the genomic basis of strain-specific 2′-FL utilization,offering a reference for future probiotic development.展开更多
Objectives:Constipation is a prevalent gastrointestinal issue,and the efficacy of probiotics in alleviating constipation has been well demonstrated.This study aimed to investigate the impact of Bifidobacterium longum ...Objectives:Constipation is a prevalent gastrointestinal issue,and the efficacy of probiotics in alleviating constipation has been well demonstrated.This study aimed to investigate the impact of Bifidobacterium longum subsp.infantis NKU FB3-14 on loperamide-induced constipation by focusing on improving intestinal barrier function and modulating gut microbiota composition.Materials and Methods:The constipated model mice induced by loperamide were treated with NKU FB3-14,and the laxative effect was assessed based on fecal water content,first black stool time and gastrointestinal transit rate.Gastrointestinal regulatory peptides in serum and intestinal neurotransmitter and inflammatory cytokines in colon tissues were measured using enzyme-linked immunosorbent assay kits.Changes in the composition of gut microbiota were analyzed through 16S ribosomal DNA(rDNA)sequencing.Additionally,high-performance liquid chromatography(HPLC)was performed to quantify levels of short-chain fatty acids(SCFAs)in feces.Results:Treatment with NKU FB3-14 increased fecal water content,shortened the first black stool time,and improved the small intestine transit rate.Motilin and substance-P significantly decreased in the model group,and only motilin increased in the FB3-14 group;somatostatin and vasoactive intestinal peptide were decreased in the model mice and both increased in the FB3-14 group;5-hydroxytryptamine(5-HT)levels in the colon tissue were upregulated following NKU FB3-14 treatment.Histological examination revealed thinner colonic mucosa in the model group along with significant increases in tumor necrosis factorα(TNF-α),interleukin 1β(IL-1β),and interleukin 17(IL-17)levels in the colon tissues,which were alleviated by NKU FB 3-14 treatment.Furthermore,NKU FB3-14 intervention resulted in reduced abundance of Desulfobacterota and Desulfovibrio while increasing the abundance of Ruminococcaceae and Eubacterium;a higher level of butyric acid was observed in feces.Conclusions:In summary,our findings demonstrated that NKU FB3-14 treatment significantly enhanced intestinal motility,regulated the expression levels of gastrointestinal regulatory peptides,prevented damage to colonic barriers,and ameliorated gut microbiota imbalance associated with loperamide-induced constipation.展开更多
Global seafood demand has continued to rise amidst challenges to traditional aquaculture operations.Current shrimp aquaculture practice requires high water exchange and discharges toxic effluent to the environment.Bio...Global seafood demand has continued to rise amidst challenges to traditional aquaculture operations.Current shrimp aquaculture practice requires high water exchange and discharges toxic effluent to the environment.Biofloc technology(BFT)is self-sustaining and emphasizes nutrient cycling through microbial activity to maintain water quality.The effect of BFT on water quality and profitability of shrimp(Litopenaeus vannamei)culture was determined over a 70-day period.Ponds P1,P2,and P3 were treated with BFT and compared to a control group(P4)without BFT.Bacillus infantis cultured inoculum initiated biofloc development while molasses-maintained C:N ratio of 15:1.One-way ANOVA determined the mean differences in Temperature,pH,dissolved oxygen(DO),total dissolved solid,alkalinity,salinity,ammonia(NH_(3)),nitrates,nitrites(NO_(2)^(-)),calcium,magnesium,as well as shrimp body weight(BW)and total length(TL)across treatments.Profitability was determined by comparing the cost of production with sales and plotting it on a bar chart.BFT shrimp exhibited significantly higher BW(13.6 g)compared to 8.1 g in the control,and maintained a higher survival rate(80–90%)by day 70.Water quality was better managed in BFT,with NH_(3) consistently kept below 0.5mg/L;transient peaks of NO_(2)^(-),more stable pH(averaging at 7.5),and better DO management,maintained above 5 mg/L.BFT provided higher profitability of Ringgit Malaysia(RM)11,019.67(P1)and RM 8651.83(P2)compared to financiallosses in the non-biofloc system.Although operational challenges were reported,BFT showed superior resilience,suggesting that proper technical training and farm management are crucial for its optimization.展开更多
Colorectal cancer is often accompanied by multiple organ metastasis.Anaerobic Bifidobacterium Infantis(BI)bacterial can selectively grow in hypoxic colorectal tumor microenvironment(TME),to own the natural advantage o...Colorectal cancer is often accompanied by multiple organ metastasis.Anaerobic Bifidobacterium Infantis(BI)bacterial can selectively grow in hypoxic colorectal tumor microenvironment(TME),to own the natural advantage of preferentially colorectal tumor targeting.Herein,a self-guidance biological hybrid drug delivery system(BI-ES-Fe Alg/DOX)based on BI was constructed to inhibit the proliferation and metastasis of colon cancer.Results demonstrated that BI-ES-Fe Alg/DOX could overcome physical barriers to target and accumulate in colon tumor tissues.Then DOX was released to kill tumor cells along with the phase transition(solid to liquid)of Fe Alg hydrogel,due to Fe3+was reduced to Fe^(2+)by intracellular GSH.Meanwhile,BI-ES selectively colonized into tumors and expressed endostatin(ES)protein to down-regulate VEGF and b FGF expression,exerting anti-angiogenic effect.Moreover,Fe Alg catalyzed H_(2)O_(2)in the local tumor to generate cytotoxic·OH,further enhancing the antitumor effect.The pharmacodynamic result in AOM/DSS model proved that BI-ES-Fe Alg/DOX had the best therapeutic effect,with the final V/V0of 2.19±0.57,which was significantly lower than the other groups.Meanwhile,on CT-26tumor-bearing model,it also showed an outstanding anti-tumor effect with inhibition rate of 82.12%±3.08%.In addition,lung metastases decreased significantly in tumor metastasis model after BI-ES-Fe Alg/DOX treatment.展开更多
The LTB of enterotoxigenic Escherichia coli (ETEC) expressed in Bifidobacterium infantis (BI) has been testified as mucosal adjuvant with co-vaccination BI-CfaB (the major fimbrial subunit) together in vivo in our pre...The LTB of enterotoxigenic Escherichia coli (ETEC) expressed in Bifidobacterium infantis (BI) has been testified as mucosal adjuvant with co-vaccination BI-CfaB (the major fimbrial subunit) together in vivo in our previous study. In order to investigate the mucosal adjuvant effect of BI-LTB to purified antigens, we oral vaccinated SD rats with recombinant BI-LTB plus OVA (rBI-LTB + OVA), and wild type BI plus OVA (wBI + OVA), OVA and PBS (Phosphate buffered saline) were vaccinated as controls, respectively. The OVA-specific sIgA in jejunal mucosa and specific IgG in serium were measured with ELISA (Enzyme-linked immunosorbent assay) and the sIgA producing cells were detected with immunohistochemistry technology (IHC) and Qwin image manipulation tools subsequently. The results shown rBI-LTB could stimulate SD rats produce high titer OVA-specific sIgA in rBI-LTB + OVA group and the OVA-specific sIgA titer in rBI-LTB + OVA group was found significant greater than that of the wBI + OVA group or OVA single group (p < 0.05). However no such significant difference was detected between the group wBI + OVA and OVA. IHC results suggested that intestinal mucosa and submucosa was the main field of sIgA secretion. These results suggested that recombinant LTB expression in BI could be used as a wide range mucosal adjuvant with different form antigens.展开更多
The most common foodborne infection in the world that leads to hospitalizations is caused by Salmonella enterica.Most Salmonella testing workflows are qualitative and only determine the presence or absence of Salmonel...The most common foodborne infection in the world that leads to hospitalizations is caused by Salmonella enterica.Most Salmonella testing workflows are qualitative and only determine the presence or absence of Salmonella,failing to quantify the contamination load present.This study aimed to standardize and validate a novel varying amplification efficiency real-time PCR assay for the detection and estimation of broad Salmonella contamination levels.The approach relies on the use of two Salmonella-specific primer-probe pairs(i.e.,invA and ttrR)with different amplification efficiencies to detect and differentiate between samples contaminated with low(1 log CFU/30 mL)or high(2-4 log CFU/30 mL)levels of Salmonella.The standardized multiplex PCR assay was validated with 131 pure culture strains and 260 laboratory-inoculated chicken-rinse samples.The multiplex assay specifically identified all Salmonella strains.The invA and ttrR primer-probe showed amplification effi-ciency of 128%and 90%,resulting in an analytic sensitivity of 0.01 and 0.1 pg/reaction for pure culture DNA samples,respectively.After a 5-h enrichment,the assay detected Salmonella in all inoculated samples and accurately identified high and low contamination levels in 87%(n=226/260)of samples.This varying amplification efficiency(VAE)assay offers a simple approach enabling the food industry to detect and identify high-risk samples contaminated by Salmonella.展开更多
基金supported by the National Natural Science Foundation of China(32021005,32272332)the Fundamental Research Funds for the Central Universities(JUSRP622020,JUSRP51501)+1 种基金the Program of Collaborative Innovation Centre of Food Safety and Quality Control in Jiangsu ProvincePostgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX22_2391)。
文摘Bifidobacterium longum subsp.infantis and Bifidobacterium adolescentis play important roles in the guts of infants and adolescents,respectively.In this study,using a neonatal rat model,we compared the protective effects of these 2 bifidobacterial species against Salmonella infection.The results demonstrated that B.longum subsp.infantis was more effective than B.adolescentis in alleviating the severity of infection in newborn rats exposed to Salmonella enterica serovar Typhimurium strain SL1344.B.longum subsp.infantis attenuated intestinal inflammation and mucosal damage induced by Salmonella infection,as well as protecting intestinal nerves and intestinal barrier function through TLR4/My D88 signalling.B.longum subsp.infantis also displayed the potential to modulate gut metabolites by promoting the biosynthesis of unsaturated fatty acids(arachidonic acid,eicosapentaenoic acid andα-linolenic acid)and purine metabolism(guanine,adenine,inosine and adenosine),thereby regulating metabolic disturbances.Additionally,the benefits of B.longum subsp.infantis were also observed in the liver,spleen and brain,improving nerve reflexes and suppressing hepatosplenomegaly.Overall,these findings provide novel insights into the prevention and treatment of gutrelated diseases in newborns,highlighting the potentially significant role of B.longum subsp.infantis in clinical applications.
基金funded by the National Key R&D Program of China(2021YFD2100700)National Natural Science Foundation of China(32021005)+1 种基金111 project(BP0719028)Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province。
文摘Bifidobacterium longum subsp.infantis is a commensal bacterium that predominates in the infant gut,playing a critical role in both preventing foreign infections and facilitating immune development.This study aimed to explore the effects of B.longum subsp.infantis supplementation on interferon-beta(IFN-β)secretion and intestinal barrier improvement in growing mice.Female and male mice were orally administered either saline or B.longum subsp.infantis CCFM1269 or I5TI(1×10^(9) CFU/mice per day,n=8)from 1-week-age until 3-,4-,and 5-week-age.RNA sequencing analysis revealed that CCFM1269 exhibited potential antiviral capacity through increasing 2'-5'oligoadenylate synthetase(OAS).Additionally,CCFM1269 supplementation significantly increased colonic IFN-β levels which combined with OAS in 3-week-old female and male mice by activating the TLR4-TRIF-dependent signaling pathway.However,this effect was not observed in 4-and 5-week-old mice.Furthermore,both CCFM1269 were found to modulate the gut microbiota composition and enhance the intestinal barrier function in 3-,4-,and 5-week-old mice.In summary,the results of this study suggested that B.longum subsp.infantis CCFM1269 promoting intestinal barrier and releasing IFN-β in growing mice was in a strain-specific and time-dependent manner.
文摘Objective： To construct Bifidobacterium Infantis/CD targeting gene therapy system. Methods： CD gene was amplified from E. Coli K12λ using PCR method, pGEX-1LamdaT plasmid and CD gene were digested with dual restriction endonucleas of EcoR Ⅰ and BamH Ⅰ and two segments of 4.9 kb and 1.3 kb were obtained. T4 DNA ligase was added to these two segments to make a recombinant CD/pGEX-1LamdaT plasmid. Then the recombinant plasmid was transfected into Bifidobacterium Infantis by electroporation. The recombinant plasmid was extracted from the positively transfected Bifidobacterium Infantis and digested with dual restriction endonucleases. Then the size of digested fragments was detected and sequencing of the gene segment inserted in extracted recombinant plasmid was performed according to the method of Sanger dideoxynucleotide triphosphate chain termination. Results： 6.2 kb recombinant plasmid was obtained from the positively transfected bacterial colony of Bifidobacterium Infantis. After being digested with dual restriction endonucleases, two segments of approximate 4.9 kb and 1.3 kb were gained from the extracted recombinant plasmid, which were equal to the size of pGEX-1LamdaT plasmid and CD gene, respectively. The full length and sequence of nucleotide acid of the inserted gene in extracted recombinant plasmid was completely identical to the CD gene. Conclusion： The foreign gene, CD gene was correctly inserted into pGEX-1LambdaT plasmid and transferred into Bifidobacterium Infantis. Bifidobacterium Infantis/CD targeting gene therapy system was successfully constructed.
基金Supported by Basic Science Research Program funded by The Innovation of Science and Technology Commission of Shenzhen Municipality,China,No.JCYJ20120828092009036Shenzhen Science and Technology Project,No.JCYJ20150403100317067
文摘AIM To determine whether oral administration of Bifidobacterium infantis CGMCC313-2(B.infantis CGMCC313-2)inhibits allergen-induced airway inflammation and food allergies in a mouse model.METHODS Ovalbumin(OVA)-induced allergic asthma and b-lactoglobulin-induced food allergy mouse models were used in this study.Following oral administration of B.infantis CGMCC313-2 during or after allergen sensitization,histopathologic changes in the lung and intestine were evaluated by hematoxylin and eosin(HE)staining.In the allergic asthma mouse model,we evaluated the proportion of lung-infiltrating inflammatory cells.OVAspecific IgE and IgG1 levels in serum and cytokine levels in bronchoalveolar lavage fluid(BALF)were also assessed.In the food allergy mouse model,the levels of total Ig E and cytokines in serum were measured.RESULTS Oral administration of B.infantis CGMCC313-2 during or after allergen sensitization suppressed allergic inflammation in lung and intestinal tissues,while the proportion of infiltrating inflammatory cells was significantly decreased in the BALF of allergic asthma mice.Moreover,B.infantis CGMCC313-2 decreased the serum levels of total Ig E in food allergy mice,and reductions in IgE and IgG1 were also observed in OVA-induced allergic asthma mice.The expression of interleukin-4(IL-4)and IL-13 in both serum and BALF was suppressed following the administration of B.infantis CGMCC313-2,while an effect on serum IL-10 levels was not observed.CONCLUSION B.infantis CGMCC313-2 inhibits the secretion of allergen-induced IgE,IL-4 and IL-13,and attenuates allergic inflammation.
基金Supported by the Doctoral Start-up Foundation of Liaoning Province,No.2021-BS-114.
文摘BACKGROUND Inflammatory bowel disease(IBD)is caused by an abnormal immune response.Programmed cell death 1(PD-1)is an immunostimulatory molecule,which interacts with PD ligand(PD-L1)playing a prime important role among autoimmune diseases.Bifidobacterium infantis(B.infantis)can promote the differentiation of CD(cluster of differentiation)4^(+)T cells into regulatory T cells(Tregs).Tregs participate in the development of IBD and may be related to disease activity.B.infantis amplify the expression level of PD-1,PD-L1 and Tregs’nuclear transcription factor forkhead box protein 3(Foxp3).But the mechanism of B.infantis on PD-1/PD-L1 signaling remains unclear.AIM To explore the mechanism of B.infantis regulating the immune response in IBD.METHODS Forty-eight-week-old BALB/c mice were randomly divided into five groups:The control group,dextran sulphate sodium(DSS)model group,DSS+B.infantis group,DSS+B.infantis+anti-PD-L1 group,and DSS+anti-PD-L1 group.The control group mice were given drinking water freely,the other four groups were given drinking water containing 5%DSS freely.The control group,DSS model group,and DSS+anti-PD-L1 group were given normal saline(NS)400μL daily by gastric lavage,and the DSS+B.infantis group and DSS+B.infantis+anti-PDL1 group were given NS and 1×109 colony-forming unit of B.infantis daily by gastric lavage.The DSS+B.infantis+anti-PD-L1 group and DSS+anti-PD-L1 group were given 200μg of PD-L1 blocker intraperitoneally at days 0,3,5,and 7;the control group,DSS+anti-PD-L1 group,and DSS+B.infantis group were given an intraperitoneal injection of an equal volume of phosphate buffered saline(PBS).Changes in PD-L1,PD-1,Foxp3,interleukin(IL)-10,and transforming growth factorβ(TGF-β)1 protein and gene expression were observed.Flow cytometry was used to observe changes in CD4^(+),CD25^(+),Foxp3^(+)cell numbers in the blood and spleen.RESULTS Compared to the control group,the expression of PD-1,Foxp3,IL-10,and TGF-β1 was significantly decreased in the intestinal tract of the DSS mice(P<0.05).Compared to the control group,the proportion of CD4^(+),CD25^(+),Foxp3^(+)cells in spleen and blood of DSS group was visibly katabatic(P<0.05).B.infantis upgraded the express of PD-L1,PD-1,Foxp3,IL-10,and TGF-β1(P<0.05)and increased the proportion of CD4^(+),CD25^(+),Foxp3^(+)cells both in spleen and blood(P<0.05).After blocking PD-L1,the increase in Foxp3,IL-10,and TGF-β1 protein and gene by B.infantis was inhibited(P<0.05),and the proliferation of CD4^(+),CD25^(+),Foxp3^(+)cells in the spleen and blood was also inhibited(P<0.05).After blocking PD-L1,the messenger ribonucleic acid and protein expression of PD-1 were invariant.CONCLUSION It is potential that B.infantis boost the proliferation of CD4^(+),CD25^(+),Foxp3^(+)T cells in both spleen and blood,as well as the expression of Foxp3 in the intestinal tract by activating the PD-1/PD-L1 pathway.
基金Supported by a grant from the Science and Technology Bureau of Sichuan Province (No. 04JY029-020-2)
文摘Objective:We recombine the suicide gene CD,UPRT into plasmid pTRKH2 and clone the recombinant dual suicide gene therapy system into tumor-hypoxia-targeting vector Bifidobacterium infantis and characterize its function.Methods:CD gene,UPRT gene and lactic acid bacteria expression plasmid pTRKH2 were digested by restriction endonuclease BamH I and Sal I,and constructed recombinant plasmids pTRKH2/CD and pTRKH2/UPRT in E.coli.The recombinant plasmids were then transfected into Bifidobacterium Infantis by electroporation.Identification of pTRKH2/CD and pTRKH2/UPRT was processed by dual restriction endonuclease digesting and sequencing.RT-PCR and SDS-PAGE were used to examine the expression of CD and UPRT genes at RNA and protein levels.The killing effects on Melanoma B16-F10 cells by pTRKH2/CD and pTRKH2/UPRT suicide gene therapy system with 5-FC were examined by MTT assay.Results:The CD gene and UPRT gene was successfully recombined into lactic acid bacteria expression plasmid pTRKH2.After dual endonuclease digestion of plasmid purified from the positively transfected E.coli,two fragments of 6.9 Kb and 1.3 Kb were found for CD gene and two fragments of 6.9 Kb and 620 bp were found for UPRT gene.The sequencing of CD gene and UPRT gene proved consistent sequences with Genebank published data.A fragment of 1.3 Kb for CD gene and fragment of 620 bp for UPRT gene was found in recombinant Bifidobacterium by RT-PCR.A 52 KDa protein for CD gene was identified in whole-cell protein of recombinant Bifidobacterium and a 26 KDa protein for UPRT gene was identified in supernatant fluid of recombinant Bifidobacterium.The survival rate of tumor cells treated by extracts from culture of recombinant Bifidobacterium with 5-FC showed a strong killing effects of pTRKH2/CD and pTRKH2/UPRT dual suicide gene therapy system on Melanoma B16-F10 cells.Conclusion:CD gene and UPRT gene are successfully inserted into pTRKH2 and transfected into tumor-hypoxia-targeting vector Bifidobacterium Infantis.This dual suicide gene therapy system shows a high efficiency for tumor cells killing.
基金supported financially by the National Natural Science Foundation of China(No.32272291)Heilongjiang Province Key Research and Development Program(Innovation Base)(No.JD2023SJ15).
文摘Bifidobacterium longum subsp.infantis(B.infantis)is the most active consumer of human milk oligosaccharides(HMOs),which can promote the development and maturation of the infant’s intestinal immune system.In this study,we collected information on B.infantis isolated from human feces in the NCBI database to analyze their whole genome.We found that the whole genome of the tested strains and the functional genes utilizing the HMOs showed geographical clustering.Comparison of the genes encodingα-L-fucosidase between B.infantis H11 and BINF revealed that strain H11 had moreα-L-fucosidase genes,and further heterologous expression ofα-Lfucosidase showed that only the glycoside hydrolase(GH)95 family could hydrolyze 2’-fucosyllactose(2’-FL).At the same time,FUC95A(derived from strain H11)was more efficient in catalyzing 2’-FL than FUC95B(derived from strain BINF).In addition,metabolites in the 2’-FL fermentation supernatants were analyzed based on untargeted metabolomics,and it was found that strain H11 could utilize 2’-FL to produce more beneficial metabolites compared to strain BINF.In conclusion,we hypothesized that the enhancement ofα-L-fucosidase activity of B.infantis is one of the essential requirements to improve the utilization of 2’-FL and increase the contents of beneficial metabolites to perform the probiotic function.
基金supported by the National Natural Science Foundation of China(32394051)the Fundamental Research Funds for the Central Universitiesthe Collaborative Innovation Centre of Food Safety and Quality Control in Jiangsu Province.
文摘The early life period is a critical phase for the colonization of initial gut microbes in infants,during which the immune system develops and matures.These processes have long-lasting implications that may extend into adolescence and even adulthood.Bifidobacterium longum subsp.infantis,recognized as an ideal probiotic during infancy,has the potential to modulate intestinal immunity and mitigate immune-mediated diseases.This research explored the potential of various B.longum subsp.infantis strains to modulate the balance between T helper(Th)1 and Th2 responses,immune cell populations,Immunoglobulin A(IgA),and the related genes expression in mice.Notably,B.longum subsp.infantis FHNFQ4M11 and CCFM1269 demonstrated more robust regulatory capabilities.These two strains,which exhibited higher ILA production,activated the aryl hydrocarbon receptor(AHR)signaling pathway,upregulated the levels of galectin-1(Gal-1)and galectin-3(Gal-3),and modulated Th1/Th2 differentiation markers in the colon.Additionally,these strains significantly elevated IgA concentrations in both serum and colon and modulated the gut microbiota composition.These findings underscored the potential of specific B.longum subsp.infantis strains as targeted probiotic interventions in early life,providing a promising strategy for promoting immune homeostasis and gut health in infants.
基金supported financially by the National Natural Science Foundation of China(No.32272291)Heilongjiang Province Key Research and Development Program(Innovation Base)(No.JD2023SJ15).
文摘Human milk oligosaccharides(HMOs)are considered the“golden ingredients”of human milk,and Bifidobacte-rium longum subsp.infantis(B.infantis)is not only indigenous probiotics of the infant gut,but also efficiently utilizes HMOs.The aim of this study was to investigate the potential manners in which B.infantis interacts with HMOs to promote intestinal health.We found that all strains of B.infantis tested had varying degrees of pro-tective effects on the cellular barrier,with B.infantis H11 being the most effective.The whole genome results of strain H11 revealed that it was enriched in genes related to HMOs consumption,and it could efficiently utilize HMOs,especially fully utilizing 2′-FL,3-FL,and DFL,utilizing about 60%of 3′-SL and 6′-SL,while the utilization of LNnT was lowest.By performing untargeted metabolomics analyses on the fermentation supernatant of strain H11 that utilized HMOs or lactose as a carbon source,it was found that strain H11 could utilize both HMOs and lactose to produce indole-3-lactic acid,indoleacetic acid,and other substances with potential probiotic functions.Furthermore,the tryptophan metabolic pathway was enriched with a variety of significantly different metabo-lites and had a large impact on the metabolic process,especially the serotonin pathway branch.In the fermentation supernatant of strain H11 utilizing HMOs as a carbon source,there was a significant increase in the levels of beneficial metabolites in the serotonin pathway.This may be one of the essential manners for the utilization of HMOs by strain H11 to exert probiotic potential.
基金supported by National Key R&D Program of China(2024YFD2100900).
文摘Although all strains of Bifidobacterium longum subsp.infantis(B.infantis)can utilize 2′-fucosyllactose(2′-FL)as a carbon source,they exhibit notable strain-level differences in utilization efficiency and genetic mechanisms.To investigate these intra-subspecific variations,we compared 2′-FL metabolism in B.infantis Y46 and the type strain B.infantis ATCC 15697 using phenotypic assays and whole-genome sequencing.Both strains were able to grow on 2′-FL as the sole carbon source,although Y46 demonstrated markedly higher growth and metabolic activity than ATCC 15697.Genomic analysis revealed Y46 has more carbohydrate metabolism genes,including 10 carbohydrate-active enzyme(CAZyme)genes absent in ATCC 15697.Despite lacking the 2′-FL transporter gene FL1_SBP,Y46 showed significantly upregulated expression of FL2_SBP,another 2′-FL transporters,and enhanced 2′-FL metabolism,suggesting an adaptive mechanism that compensates for FL1_SBP loss.These findings highlight the metabolic flexibility and ecological adaptability of Y46 and provide insight into the genomic basis of strain-specific 2′-FL utilization,offering a reference for future probiotic development.
基金funded by the Fundamental Research Funds for the Central Universities,Nankai University,China(Nos.63241340 and 63241341).
文摘Objectives:Constipation is a prevalent gastrointestinal issue,and the efficacy of probiotics in alleviating constipation has been well demonstrated.This study aimed to investigate the impact of Bifidobacterium longum subsp.infantis NKU FB3-14 on loperamide-induced constipation by focusing on improving intestinal barrier function and modulating gut microbiota composition.Materials and Methods:The constipated model mice induced by loperamide were treated with NKU FB3-14,and the laxative effect was assessed based on fecal water content,first black stool time and gastrointestinal transit rate.Gastrointestinal regulatory peptides in serum and intestinal neurotransmitter and inflammatory cytokines in colon tissues were measured using enzyme-linked immunosorbent assay kits.Changes in the composition of gut microbiota were analyzed through 16S ribosomal DNA(rDNA)sequencing.Additionally,high-performance liquid chromatography(HPLC)was performed to quantify levels of short-chain fatty acids(SCFAs)in feces.Results:Treatment with NKU FB3-14 increased fecal water content,shortened the first black stool time,and improved the small intestine transit rate.Motilin and substance-P significantly decreased in the model group,and only motilin increased in the FB3-14 group;somatostatin and vasoactive intestinal peptide were decreased in the model mice and both increased in the FB3-14 group;5-hydroxytryptamine(5-HT)levels in the colon tissue were upregulated following NKU FB3-14 treatment.Histological examination revealed thinner colonic mucosa in the model group along with significant increases in tumor necrosis factorα(TNF-α),interleukin 1β(IL-1β),and interleukin 17(IL-17)levels in the colon tissues,which were alleviated by NKU FB 3-14 treatment.Furthermore,NKU FB3-14 intervention resulted in reduced abundance of Desulfobacterota and Desulfovibrio while increasing the abundance of Ruminococcaceae and Eubacterium;a higher level of butyric acid was observed in feces.Conclusions:In summary,our findings demonstrated that NKU FB3-14 treatment significantly enhanced intestinal motility,regulated the expression levels of gastrointestinal regulatory peptides,prevented damage to colonic barriers,and ameliorated gut microbiota imbalance associated with loperamide-induced constipation.
基金supported by Ministry of Higher Education,Malaysia through the Translational Research Program entitled Program Traslasional Sektor Makanan Laut Malaysia untuk Kelestarian Pengeluaran Udang Marin dan Penjanaan Pendapatan-Tinggi:Aplikasi Teknologi“Rapid Biofloc”(UMT/PPIJIM/2-2/68/Trans-KPT)grant number[Vot.No:58932].
文摘Global seafood demand has continued to rise amidst challenges to traditional aquaculture operations.Current shrimp aquaculture practice requires high water exchange and discharges toxic effluent to the environment.Biofloc technology(BFT)is self-sustaining and emphasizes nutrient cycling through microbial activity to maintain water quality.The effect of BFT on water quality and profitability of shrimp(Litopenaeus vannamei)culture was determined over a 70-day period.Ponds P1,P2,and P3 were treated with BFT and compared to a control group(P4)without BFT.Bacillus infantis cultured inoculum initiated biofloc development while molasses-maintained C:N ratio of 15:1.One-way ANOVA determined the mean differences in Temperature,pH,dissolved oxygen(DO),total dissolved solid,alkalinity,salinity,ammonia(NH_(3)),nitrates,nitrites(NO_(2)^(-)),calcium,magnesium,as well as shrimp body weight(BW)and total length(TL)across treatments.Profitability was determined by comparing the cost of production with sales and plotting it on a bar chart.BFT shrimp exhibited significantly higher BW(13.6 g)compared to 8.1 g in the control,and maintained a higher survival rate(80–90%)by day 70.Water quality was better managed in BFT,with NH_(3) consistently kept below 0.5mg/L;transient peaks of NO_(2)^(-),more stable pH(averaging at 7.5),and better DO management,maintained above 5 mg/L.BFT provided higher profitability of Ringgit Malaysia(RM)11,019.67(P1)and RM 8651.83(P2)compared to financiallosses in the non-biofloc system.Although operational challenges were reported,BFT showed superior resilience,suggesting that proper technical training and farm management are crucial for its optimization.
基金supported by National Natural Science Foundation of China(82102918)Youth Talent Promotion Project in Henan Province(2020HYTP011)。
文摘Colorectal cancer is often accompanied by multiple organ metastasis.Anaerobic Bifidobacterium Infantis(BI)bacterial can selectively grow in hypoxic colorectal tumor microenvironment(TME),to own the natural advantage of preferentially colorectal tumor targeting.Herein,a self-guidance biological hybrid drug delivery system(BI-ES-Fe Alg/DOX)based on BI was constructed to inhibit the proliferation and metastasis of colon cancer.Results demonstrated that BI-ES-Fe Alg/DOX could overcome physical barriers to target and accumulate in colon tumor tissues.Then DOX was released to kill tumor cells along with the phase transition(solid to liquid)of Fe Alg hydrogel,due to Fe3+was reduced to Fe^(2+)by intracellular GSH.Meanwhile,BI-ES selectively colonized into tumors and expressed endostatin(ES)protein to down-regulate VEGF and b FGF expression,exerting anti-angiogenic effect.Moreover,Fe Alg catalyzed H_(2)O_(2)in the local tumor to generate cytotoxic·OH,further enhancing the antitumor effect.The pharmacodynamic result in AOM/DSS model proved that BI-ES-Fe Alg/DOX had the best therapeutic effect,with the final V/V0of 2.19±0.57,which was significantly lower than the other groups.Meanwhile,on CT-26tumor-bearing model,it also showed an outstanding anti-tumor effect with inhibition rate of 82.12%±3.08%.In addition,lung metastases decreased significantly in tumor metastasis model after BI-ES-Fe Alg/DOX treatment.
文摘The LTB of enterotoxigenic Escherichia coli (ETEC) expressed in Bifidobacterium infantis (BI) has been testified as mucosal adjuvant with co-vaccination BI-CfaB (the major fimbrial subunit) together in vivo in our previous study. In order to investigate the mucosal adjuvant effect of BI-LTB to purified antigens, we oral vaccinated SD rats with recombinant BI-LTB plus OVA (rBI-LTB + OVA), and wild type BI plus OVA (wBI + OVA), OVA and PBS (Phosphate buffered saline) were vaccinated as controls, respectively. The OVA-specific sIgA in jejunal mucosa and specific IgG in serium were measured with ELISA (Enzyme-linked immunosorbent assay) and the sIgA producing cells were detected with immunohistochemistry technology (IHC) and Qwin image manipulation tools subsequently. The results shown rBI-LTB could stimulate SD rats produce high titer OVA-specific sIgA in rBI-LTB + OVA group and the OVA-specific sIgA titer in rBI-LTB + OVA group was found significant greater than that of the wBI + OVA group or OVA single group (p < 0.05). However no such significant difference was detected between the group wBI + OVA and OVA. IHC results suggested that intestinal mucosa and submucosa was the main field of sIgA secretion. These results suggested that recombinant LTB expression in BI could be used as a wide range mucosal adjuvant with different form antigens.
文摘The most common foodborne infection in the world that leads to hospitalizations is caused by Salmonella enterica.Most Salmonella testing workflows are qualitative and only determine the presence or absence of Salmonella,failing to quantify the contamination load present.This study aimed to standardize and validate a novel varying amplification efficiency real-time PCR assay for the detection and estimation of broad Salmonella contamination levels.The approach relies on the use of two Salmonella-specific primer-probe pairs(i.e.,invA and ttrR)with different amplification efficiencies to detect and differentiate between samples contaminated with low(1 log CFU/30 mL)or high(2-4 log CFU/30 mL)levels of Salmonella.The standardized multiplex PCR assay was validated with 131 pure culture strains and 260 laboratory-inoculated chicken-rinse samples.The multiplex assay specifically identified all Salmonella strains.The invA and ttrR primer-probe showed amplification effi-ciency of 128%and 90%,resulting in an analytic sensitivity of 0.01 and 0.1 pg/reaction for pure culture DNA samples,respectively.After a 5-h enrichment,the assay detected Salmonella in all inoculated samples and accurately identified high and low contamination levels in 87%(n=226/260)of samples.This varying amplification efficiency(VAE)assay offers a simple approach enabling the food industry to detect and identify high-risk samples contaminated by Salmonella.
