Lactiplantibacillus plantarum 104,which was previously screened in the laboratory,has been confirmed to have the effect of lowering lipids and regulating intestinal microbial homeostasis.However,the mechanism of actio...Lactiplantibacillus plantarum 104,which was previously screened in the laboratory,has been confirmed to have the effect of lowering lipids and regulating intestinal microbial homeostasis.However,the mechanism of action of its fermentation supernatant in alleviating metabolic disorders is unclear.L.plantarum 104 cell-free supernatant(LP104s)was fed to high-fat diet C57BL/6N mice for 8 weeks.The intervention of LP104s increased the concentration of conjugated bile acids in the ileum,especially taur-α/β-muricholic acid sodium salt(T-α-MCA or T-β-MCA),inhibited intestinal farnesoid X receptor(FXR)-related signaling pathways.LP104s reduced cholesterol levels by increasing the synthesis of hepatic cholic acid(CA),chenodeoxycholic acid(CDCA),and the excretion of bile acids in feces.Moreover,Western blotting results showed that TLR2/NF-κB signaling pathway expression was inhibited.In addition,16S r RNA sequencing results showed that LP104s regulated the relative abundance of bacteria associated with inflammatory response and obesity(Prevotella,Ruminococcus,and Clostridium).Therefore,this paper further elaborates the role of gut microbiology and bile acids in improving metabolism from the perspective of secondary bile acids and intestinal chronic inflammation and also lays a theoretical foundation for the next step in the development of fermentation products of this strain.展开更多
BACKGROUND Bacillus subtilis(B.subtilis),Enterococcus faecium(E.faecium),and Enterococcus faecalis(E.faecalis)are probiotics that are widely used in the clinical treatment of irritable bowel syndrome(IBS).Whether the ...BACKGROUND Bacillus subtilis(B.subtilis),Enterococcus faecium(E.faecium),and Enterococcus faecalis(E.faecalis)are probiotics that are widely used in the clinical treatment of irritable bowel syndrome(IBS).Whether the supernatants of these three probiotics can improve gastrointestinal sensation and movement by regulating the serotonin transporter(SERT)expression needs to be clarified.AIM To investigate whether B.subtilis,E.faecium,and E.faecalis supernatants can upregulate SERT expression in vitro and in vivo.METHODS Caco-2 and HT-29 cells were stimulated with probiotic culture supernatants for 12 and 24 h,respectively.A male Sprague-Dawley rat model of post-infectious irritable bowel syndrome(PI-IBS)was established and the rats were treated with phosphate-buffered saline(group A)and three probiotics culture supernatants(groups B,C,and D)for 4 wk.The levels of SERT were detected by quantitative PCR and western blotting.RESULTS The levels of SERT at post-treatment 12 and 24 h were significantly elevated in Caco-2 cells treated with B.subtilis supernatant compared with those in the control group(aP<0.05).Those levels were markedly upregulated in Caco-2 cells stimulated with E.faecium and E.faecalis supernatants at 24 h(aP<0.05).In addition,SERT expression in groups B,C,and D was significantly higher than that in group A in the 2nd wk(aP<0.05).Increased SERT expression was only found in group D in the 3rd wk(aP<0.05).However,there was no significant difference in SERT expression between the groups in the last week(P>0.05).CONCLUSION The supernatants of B.subtilis,E.faecium,and E.faecalis can upregulate SERT expression in intestinal epithelial cells and the intestinal tissues in the rat model of PI-IBS.展开更多
A novel technology using Fe powder as reducing agent for Ge and Cu recovery from precipitating vitriol supernatant in Zn hydrometallurgical plant was investigated. The results show that reaction time, temperature, agi...A novel technology using Fe powder as reducing agent for Ge and Cu recovery from precipitating vitriol supernatant in Zn hydrometallurgical plant was investigated. The results show that reaction time, temperature, agitation speed, initial pH value of solution and the amount of reducing Fe have significant effects on recovering Ge and Cu, and the optimum process operating parameters are established as follows： time 120 min, initial pH value 1.5, the dosage of reducing Fe powder 4 g/L, agitation speed 600 r/min and temperature 80 °C. Under these experimental conditions, the recovery ratios of Ge and Cu from precipitating vitriol supernatant in Zn hydrometallurgical plant can reach 96% and 100%, respectively. The content of Ge in the reduced residue reaches up to 2.06% （mass fraction）, indicating that the separation and enrichment of Ge from the Zn sulfate solution is realized. The grade of Ge and Cu can reach up to 4.88% and 56.75%, respectively, when the reduced residue is further processed.展开更多
AIM To evaluate the effect of Lactobacillus rhamnosus GG supernatant(LGG-s) on the expression of serotonin transporter(SERT) in rats with post-infectious irritable bowel syndrome(PI-IBS).METHODS Campylobacter jejuni 8...AIM To evaluate the effect of Lactobacillus rhamnosus GG supernatant(LGG-s) on the expression of serotonin transporter(SERT) in rats with post-infectious irritable bowel syndrome(PI-IBS).METHODS Campylobacter jejuni 81-176(1010 CFU/m L) was used to induce intestinal infection to develop a PI-IBS model. After evaluation of the post-infectious phase by biochemical tests, Dn A agarose gel electrophoresis, abdominal withdrawal reflex(AWR) test, and the intestinal motility test, four PI-IBS groups received different concentrations of LGG-s for 4 wk. The treatments were maintained for 1.0, 2.0, 3.0 or 4.0 wk during the experiment, and the colons and brains were removed for later use each week. SERT m Rn A and protein levels were detected by real-time PCR and Western blot, respectively.RESULTS The levels of SERT m Rn A and protein in intestinal tissue were higher in rats treated with LGG-s than in control rats and PI-IBS rats gavaged with PBS during the whole study. Undiluted LGG-s up-regulated SERT m Rn A level by 2.67 times compared with the control group by week 2, and SERT m Rn A expression kept increasing later. Double-diluted LGG-s was similar to undiluted-LGG-s, resulting in high levels of SERT m Rn A. Triple-diluted LGG-s up-regulated SERT m Rn A expression level by 6.9-times compared with the control group, but SERT m Rn A expression decreased rapidly at the end of the second week. At the first week, SERT protein levels were basically comparable in rats treated with undiluted LGG-s, double-diluted LGG-s, and triplediluted LGG-s, which were higher than those in the control group and PBS-treated PI-IBS group. SERT protein levels in the intestine were also comparable in rats treated with undiluted LGG-s, double-diluted LGG-s, and triple-diluted LGG-s by the second and third weeks. SERT m Rn A and protein levels in the brain had no statistical difference in the groups during the experiment.CONCLUSION LGG-s can up-regulate SERT m Rn A and protein levels in intestinal tissue but has no influence in brain tissue in rats with PI-IBS.展开更多
N-dodecanoyl homoserine lactone（C（12）-HSL）was detected in the supernatant of an anammox granular sludge reactor（AGSR）.C（12）-HSL could enhance the specific anammox activity of anammox biomass.Adding C（12）-HSL...N-dodecanoyl homoserine lactone（C（12）-HSL）was detected in the supernatant of an anammox granular sludge reactor（AGSR）.C（12）-HSL could enhance the specific anammox activity of anammox biomass.Adding C（12）-HSL-containing AGSR supernatant into the continuously stirred tank reactors reduced the start-up time of the anammox process from80 to 66 days.Moreover,the nitrogen loading rate was also enhanced to 1.6 times that of the control reactor.AHLs could increase the secretion of extracellular polymeric substances and anammox obtained better enrichment with the addition of AHLs-containing AGSR supernatant.Denaturing gradient gel electrophoresis analysis further revealed that AHLs played a role in mediating microbial community parameters.In conclusion,adding AHL-containing supernatant could be an effective and economical way to accelerate the start-up of anammox.展开更多
The rheological properties in the supernatant of peach gum from Prunnus dulcis were discussed in order to provide more scientific technical parameters and references for developing peach gum as a kind of medicinal gum...The rheological properties in the supernatant of peach gum from Prunnus dulcis were discussed in order to provide more scientific technical parameters and references for developing peach gum as a kind of medicinal gum.The rheological properties in the supernatant of peach gum were comparatively studied in different material ratios,temperatures,shaking times,pH values and salinities.The results show that,1) the mathematical model of shear rate with material ratio and shear stress is Y=0.069X12+0.035X2 -1.174,R2=0.942;2) the mathematical model of shear rate with temperature and shear stress is Y=4.936X12+0.023 2X2-1.688,R2=0.937;3) the mathematical model of shear rate with shaking time and shear stress is Y=0.005 192 X13-0.140 73X12+1.249 045X1+ 0.036 546 X2-3.644 29,R2=0.954 3;4) the effects of pH value on the rheological properties in the supernatant of peach gum are comparatively complicated with a varying range of 3-11 and the shear rate shows a change trend of saddle model;5) the mathematical model of shear rate with the concentration of NaCl and shear stress is Y=-0.037 44X1+0.012 93 X2,R2=0.998;6) the mathematical model of shear rate with the concentration of CaCl2 and shear stress is Y=0.025 789X1+0.016 19X2,R2 =0.999;and 7) the mathematical model of shear rate with the concentration of sorbic acid potassium and shear stress is Y=0.079 5X1+0.017 3X2,R2=0.998.The results show that the material ratio,temperature,shaking time,pH value significantly affect the rheological properties in the supernatant of peach gum,and the concentrations of NaCl and CaCl2 also significantly affect the rheological properties expect the concentration of sorbic acid potassium.展开更多
A combined nitritation–anammox reactor was developed to treat the digestion supernatant under various C/N ratios. Due to the difficulties for heterotroph to utilize the refractory organics, the reactor presented rela...A combined nitritation–anammox reactor was developed to treat the digestion supernatant under various C/N ratios. Due to the difficulties for heterotroph to utilize the refractory organics, the reactor presented relatively stable performance with increasing supernatant addition. Nevertheless, the adverse effects of supernatant would accumulate during the long-term operation and thus weakened the activity and shock resistance of microbes,which further led to the gradual decrease of reactor performance after 92 days＇ operation.Under this circumstance, supernatant with volatile fatty acids（VFAs） residuals was further introduced into the reactor to investigate the performance of combined nitritation–anammox process with VFA addition. With the appearance of VFAs, the nitrogen removal performance gradually restored and the reactor finally achieved stable and efficient performance with C/N ratio of 0.35. The VFA residuals within 150 mg/L in the supernatant served as the extra electron donors and stimulated the heterotrophic denitrification process, which was vital for the enhancement of reactor. The nitrogen removal rate and total nitrogen removal efficiency reached 0.49 kg N/（m^3·day） and 88.8% after 140 days＇ operation, respectively. The combined nitritation–anammox reactor was proved suitable to treat digestion supernatant.展开更多
The bioactivities of culture supernatants from retroviral packaging cells carrying the mouse Fas ligand (mFasL) gene was investigated. FasLcDNA was cloned into PLXIN with an internal ribosome entry site to link two ci...The bioactivities of culture supernatants from retroviral packaging cells carrying the mouse Fas ligand (mFasL) gene was investigated. FasLcDNA was cloned into PLXIN with an internal ribosome entry site to link two cistrons through gene recombination technology, PLXIN and the recombinant vector PLFIN were separately transfected into PA317 retrovirus packing cell line by lipofectamine 2000, and the resistant clones were selected with G418 selective medium. The integration of genome DNA was assayed by genomic DNA PCR. NIH3T3 cells were transduced by the culture supernatants from PA317 carrying the mFasLcDNA gene, and were selected with G418 selective medium, so as to select the PLFIN-PA317 clone capable of producing higher titer of supernatants. The levels of mFasL protein on NIH3T3 cells membrane were assayed by flow cytometry (FCM). The biological activity of mFasL on NIH3T3 cells membrane was investigated by the inducing apoptosis of Fas + Yac-1 cells co-cultured with NIH3T3 cells expressing Fas ligand. To explore the direct mFasL cytotoxicity of culture supernatants from retroviral packaging cells carrying the mFasL gene, the culture supernatants from PLFIN-PA317 and PLXIN-PA317 were separately co-cultured with Yac-1 cells in parallel. The recombinant PLFIN was successfully constructed. The highest titer of supernatants from twelve resistant clones was 8.5×10 5 colony-forming-unit (CFU)/ml. The NIH3T3 cells transfected by above supernatants had a higher level of mFasL (53.81±6.9 %), and significantly induced the apoptosis of Fas + Yac-1 cells (56.78±4.5 %), as both were cocultured for 5 h at 1∶1 ratio, whereas it is 7.08±3.4 % in control group (P<0.01). Supernatant from PLFIN-PA317 could also directly induce the apoptosis of Yac-1 within 5 h of incubation. Thus, the culture supernatants from PLFIN-PA317 possessed both infectivity and cytotoxicity of mFasL.展开更多
The proliferation of splenocytes from health adults was induced by anti-CD3 McAb and IL-2.The proliferative potential of the splenocytes and antitumor activity of their culture supernatants of splenocytes were studie...The proliferation of splenocytes from health adults was induced by anti-CD3 McAb and IL-2.The proliferative potential of the splenocytes and antitumor activity of their culture supernatants of splenocytes were studied.The results showed that anti-CD3 McAb not only enhanced the proliferation of the splenocytes directly,but also enhanceil that of induced by IL-2.Their enhancing effect was more significant when the incubation time in vitro was prolonged.The culture supernatants of anti-CD3 and IL-2 induced splenocytes also had the antitumor activity and enhancing capability to the antitumor activity of LAK tells.The results suggested that LAK cells could secret lymphokine,and this effect would be synergically promoted when anti-CD3 and IL-2 were simultaneously used.展开更多
Phosphorus is an irreplaceable and depletable element. Furthermore, it has an almost one-way circulation on earth, so it is necessary to close the phosphorus cycle loop. Phosphorus could be recovered as struvite, whic...Phosphorus is an irreplaceable and depletable element. Furthermore, it has an almost one-way circulation on earth, so it is necessary to close the phosphorus cycle loop. Phosphorus could be recovered as struvite, which is a good slow-released fertilizer for agriculture. The supernatant of anaerobic digestion used to treat sludge from wastewater treatment plant is one main source from which phosphorus can be recovered. Studies have proven that phosphorus recovery from digester supematant is a feasible choice to preserve phosphorus rock technically and economically. A modified ＂PHOSNIX＂ P-recovery process was applied under the operating conditions of a 9.0 pH value and a 1.8 mg： P ratio with the influent of the centrate coming from the sludge centrifuge of the Songjiang Wastewater Treatment Plant in Shanghai. More than 80% influent phosphorus was recovered as struvite. Crystal products with good purity and low heavy metal content were gained. The largest crystal had a length of up to 0.26 mm. It was found in our study that the reaction time did not play an important role in crystal growth. Therefore, the optimization of the reaction condition for crystal growth should be examined in future study.展开更多
Aspergillus parasiticus, a common fungal contaminant in food, produces aflatoxin B1, which is classified as human carcinogen. Kefir is an ancient fermented beverage obtained by the fermentation of different substrates...Aspergillus parasiticus, a common fungal contaminant in food, produces aflatoxin B1, which is classified as human carcinogen. Kefir is an ancient fermented beverage obtained by the fermentation of different substrates with kefir grains. A very important waste produced by the dairy cheese industry is the whey permeate, which nowadays is a strong ambient contaminant. The aim of this work was to assess the effect of whey permeates fermented with kefir grains against A. parasiticus growth, aflatoxin B1 biosynthesis, and the kefir microorganisms protection against the cell damage produced by aflatoxin B1. It was observed that kefir-cell-free-supernatants (CFS) produced fungal inhibition. A fungicidal effect was observed with 65% v/v of CFS in the culture medium (final pH 4.55 and total undissociated lactic and acetic acid concentration 34.08 mM). Under these conditions, aflatoxin production was not detected. Finally, it was found that non-viable kefir microorganisms protected HepG2 cells from the damage produced by aflatoxin B1.展开更多
Background Our previous study showed the 150 mg/mL fetal cardiac supernatant （FCS） could induce differentiation of BMSCs into cardiomyocye-like cells without cardiomyocyte touch,but differentiation efficiency is not...Background Our previous study showed the 150 mg/mL fetal cardiac supernatant （FCS） could induce differentiation of BMSCs into cardiomyocye-like cells without cardiomyocyte touch,but differentiation efficiency is not high enough.Inhibition of glycogen synthase kinase-3 enhanced the proliferation and survives of stem cells.We tested if 6-bromoindirubin-3-oxime （BIO,glycogen synthase kinase-3 inhibitor） enhances the effects of FCS on differentiation of BMSCs and explore the growth factors in FCS.Methods BMSCs were isolated from the femur and tibia of four-week-old male Sprague-Dawley rats and co-cultured with FCS （150 mg/mL） that was made from fetal hearts from nineteen-day pregnant Wistar rats.BIO with different concentration （0,1,10,and 100 nM） was introduced in culture dishes.Transforming growth factor beta 1 （TGF-β1）,bone morphogenetic protein 2 （BMP-2） and Akt in cardiac supernatant and culture medium were assayed with ELISA methods.Results After co-culturing with FCS,beating myotubes were observed in 25.9 % BMSCs dishes after 1 to 2 weeks＇ culture.The levels of TGF-β1 and BMP-2 in FCS concentrations were no more than that in young and adult cardiac supernatant.All BIO groups significantly enhanced the effects of FCS on differentiation of BMSCs into the cardiomyocyte-like cells （1 nM,83 %;10 nM,73 %;100 nM,100 %）.Akt levels were higher in BMSCs cultural medium with FCS.Conclusions FCS could induce the differentiation of BMSCs into the cardiomyocyte-like cells.TGF-β1 and BMP-2 might not play a role in the differentiation of BMSCs induced by FCS.BIO enhanced the effects of FCS on the differentiation of BMSCs into cardiomyocyte-like cells,which might involve the Akt pathway.展开更多
[Objective] Pseudomonas as one of the dominant spoilage bacteria highly form biofilms in chilled meat products and processing environment when contaminating single or mixed with other species.This study aims to invest...[Objective] Pseudomonas as one of the dominant spoilage bacteria highly form biofilms in chilled meat products and processing environment when contaminating single or mixed with other species.This study aims to investigate the antibiofilm properties of the cell-free supernatants(CFSs) of three Bacillus species isolated from fermented food and rice seeds on Pseudomonas lundensis(PL) or and Acinetobacter johnsonii(AJ) as mono-or dual-species.[Methods] Biofilm biomass,extracellular polymeric substances(EPSs),and biofilm structure were measured by crystal violet staining,spectrophotometry,confocal laser scanning microscopy(CLSM),respectively,as well as transcription of biofilm-related genes determined by qPCR.[Results] The CFSs of Bacillus amyloliquefaciens ZG08,B.velezensis B5,and B.subtilis YB11 inhibited the biofilm formation of PL and AJ without affecting their growth.The treatment with 50% CFSs of ZG08 and B5 decreased the cell viability of two biofilms by 12.73%–21.04%,which was higher than that of YB11(0.15%–4.38%).The inhibition rates of 50% CFSs of the three strains were 59.75%–79.59% against the PL biofilm and 63.62%–78.57% against the biofilm of PL+AJ,in which the CFS of YB11 had weaker activity.The content of exopolysaccharides and exoprotein in the two biofilms treated with these CFSs were reduced by 53.77%–73.30% and 54.84%–62.38%,respectively.The treatment with the three CFSs also reduced the adhesive cells,loosened biofilm structures,and thinned their thickness by 57.63%–74.49% and 60.43%–64.64%,respectively.Moreover,the CFSs of ZG08 and B5 effectively eradicated by 41.77%–69.79% against the mature biofilms of PL and PL+AJ,compared to weak activity of YB11.In addition,the antibiofilm activities of the three CFSs were stable under four enzyme digestion and heating conditions.Compared with the control,the CFSs of ZG08 and B5 significantly down-regulated the expression of six biofilm-related genes,lapA,alg44,pelG,luxR,wspR,and rpoS.[Conclusion] The CFSs of ZG08 and B5 have strong antibiofilm activities against PL and AJ as mono-or dual-species.展开更多
The biotechnological industry faces a crucial demand for novel bioactive compounds,particularly antimicrobial agents,to address the rising challenge of bacterial resistance to current available antibiotics.Traditional...The biotechnological industry faces a crucial demand for novel bioactive compounds,particularly antimicrobial agents,to address the rising challenge of bacterial resistance to current available antibiotics.Traditional strate-gies for cultivating naturally occurring microorganisms often limit the discovery of novel antimicrobial producers.This study presents a protocol for targeted selection of bacterial strains using the supernatant of Paenibacillus el-gii,which produces abundant signal molecules and antimicrobial peptides.Soil samples were inoculated in these enriched culture media to selectively cultivate bacteria resistant to the supernatant,indicating their potential to produce similar compounds.The bacterial strains isolated through this method were assessed for their antibac-terial activity.In addition,the functional annotation of the genome of one of these strains revealed several gene clusters of biotechnological interest.This study highlights the effectiveness of using this approach for selective cultivation of microorganisms with potential for biotechnological applications.展开更多
This research aimed to study the evolution of ATP-related compounds in dry-cured ham and to assess their suitability as chemical markers of food contamination.A rapid high-performance liquid chromatography(HPLC)method...This research aimed to study the evolution of ATP-related compounds in dry-cured ham and to assess their suitability as chemical markers of food contamination.A rapid high-performance liquid chromatography(HPLC)method was developed for the analysis of five ATP-related compounds namely,ATP,ADP,AMP,hypoxanthine,and Ino in sliced dry-cured ham.Moreover,a positive correlation between ATP content and microbial load was found in ham during storage.In addition,the method developed herein was employed to quantify ATP-related compounds in sliced dry-cured ham wrapped in a novel antibacterial packaging film containing the cell-free supernatant(CFS)of a probiotic Lactiplantibacillus plantarum strain.The contents of ATP-related compounds in ham samples wrapped in the antibacterial packaging film were lower than in control samples during the 7 days of storage(181 vs 269 mg/kg on day 2;247 vs 286 mg/kg on day 5;272 vs 297 mg/kg on day 7).Thus,the evaluated CFS could be considered in packaging material applications for the preservation of sliced ham.This study presents an effective method to assess the quality of sliced ham,which might also contribute to the adoption of active packaging in the food industry.展开更多
Helicobacter pylori,a carcinogenic bacterium,poses a significant health risk and raises concerns about food safety,particularly through transmission via dairy products.Lactic acid bacteria(LAB)fermentation supernatant...Helicobacter pylori,a carcinogenic bacterium,poses a significant health risk and raises concerns about food safety,particularly through transmission via dairy products.Lactic acid bacteria(LAB)fermentation supernatants have shown antibacterial activity against H.pylori,but their metabolites and mechanisms remain unclear.In this study,the cell-free fermentation supernatant of Latilactobacillus sakei LZ217(LZ217-CFS)exhibited superior antibacterial effects compared to colloidal bismuth subcitrate,inducing H.pylori apoptosis with nucleic acid and protein leakage.Metabolomics,network pharmacology,and molecular docking identified key antibacterial metabolites(such as L-glyceraldehyde and niacin)in LZ217-CFS and their targets.The results suggested that the activities of two enzymes,IMP dehydrogenase and GTP cyclohydrolase II identified as the primary targets,were significantly inhibited by LZ217-CFS.Moreover,LZ217-CFS significantly affected H.pylori’s central carbon metabolism,purine metabolism,and riboflavin metabolism.This discovery unveils a novel mechanism for H.pylori inhibition,supporting LAB fermentation supernatants’potential as natural preservatives in food safety,enhancing quality.展开更多
Ferns,a common class of wild edible plants(WEPs),are highly nutritious,but they are prone to rapid spoilage.Thus,developing effective preservation methods for ferns is necessary.Initially,this study confirmed that Pse...Ferns,a common class of wild edible plants(WEPs),are highly nutritious,but they are prone to rapid spoilage.Thus,developing effective preservation methods for ferns is necessary.Initially,this study confirmed that Pseudomonas spp.primarily causes the decay of ferns.Subsequently,the potential of combining the cell-free supernatant(CFS)of lactic acid bacteria with natural aromatic compounds as a green preservative agent was explored.In particular,this study focused on the combined use of Lactobacillus paracasei Z21 CFS(LCFS)and thymol(LCFS-T)to target spoilage bacteria Pseudomonas aeruginosa and Pseudomonas putida,and to elucidate their antibacterial and antibiofilm mechanisms.Results indicated that LCFS-T significantly enhanced bactericidal activity while reducing dosages compared with either agent alone.Bacterial content leakage,cell membrane permeability assays,and scanning electron microscopy analysis indicated that LCFS-T caused remarkable changes in cell membrane permeability and integrity.The swimming motility assay and light microscopy observation of biofilms demonstrated that the antibiofilm activity of LCFS-T was due to the inhibition of flagellar motility.Notably,treatment with LCFS-T effectively delayed spoilage in ferns,thereby extending their shelf life by an additional 9 days.Compared with the control group,the ferns treated with LCFS-T maintained their color,texture,and overall quality.This study highlights LCFS-T as a promising natural food preservative,providing an effective strategy to mitigate food safety risks associated with WEPs and to support the development of sus-tainable preservation methods.展开更多
Aflatoxin,a harmful secondary metabolite produced by Aspergillus flavus and Aspergillus parasiticus,poses a significant risk to human health and food safety.Therefore,the development of safe and environmentally friend...Aflatoxin,a harmful secondary metabolite produced by Aspergillus flavus and Aspergillus parasiticus,poses a significant risk to human health and food safety.Therefore,the development of safe and environmentally friendly techniques for controlling A.flavus and its aflatoxin production is imperative.In this study,Bacillus velezensis 906 cell-free fermentation supernatant(CFS)inhibited the germination of A.flavus spores and myce-lium growth.Scanning electron microscopy and fluorescence microscopy revealed that CFS altered cell morphology and damaged the cell membrane of A.flavus leading to cell death.Fourier transform infrared spectroscopy indicated changes in the functional groups of A.flavus filaments treated with CFS.The trend in ergosterol content demonstrated that CFS effectively inhibited the normal growth of A.flavus cell membranes.The CFS exhibited remarkable efficacy in degrading aflatoxin B1(AFB1),achieving a degradation rate of up to 60%after 48 h of interaction.The addition of 0.2 mg/mL Cu^(2+)or Fe^(3+)metal ions to CFS significantly increased the degradation rate of AFB1 up to 90%.Furthermore,the analysis indicated that the active components responsible for AFB1 degradation might be heat-resistance and exhibit resistance to protease K.These findings underscore the potential of CFS as a green,safe,and economically viable strategy for controlling aflatoxin production by A.flavus,offering promising prospects for mitigating mold contamination in food and feed applications.展开更多
This study reports the development of a novel oil-in-water nanoemulsion system composed of Lactobacillus plantarum SC21 cell-free supernatant(LCFS),Litsea cubeba essential oil(LCEO),and soy lecithin(SL).Through system...This study reports the development of a novel oil-in-water nanoemulsion system composed of Lactobacillus plantarum SC21 cell-free supernatant(LCFS),Litsea cubeba essential oil(LCEO),and soy lecithin(SL).Through systematic characterization,this study revealed that the nanoemulsions exhibited a uniform spherical morphology,stable dispersion,and minimal aggregation.These findings demonstrated the formation of a robust interfacial structure,likely via molecular interactions such as hydrogen bonds and electrostatic forces.The encapsulation of bioactive compounds within this system significantly enhanced their functional performance.Specifically,LCFS-LCEO nanoemulsions(LCFS-LCEO-NEs)showed improved antioxidant activity and stronger antibacterial effects against common spoilage microorganisms(Pseudomonas aeruginosa and Pseudomonas putida)in fiddlehead ferns than LCFS and LCEO alone,and it outperformed the simple physical mixture of LCFS and LCEO,highlighting the crucial role of the nanoencapsulation process.When applied to fiddlehead ferns during storage at 4℃,LCFS-LCEO-NEs effectively hindered quality loss by delaying browning,senescence,and moisture loss,thereby extending the postharvest shelf life to 24 days.Additionally,the textural properties and key nutritional components of fiddlehead ferns were also maintained during refrigerated storage,and key browningrelated enzymes such as polyphenol oxidase and peroxidase were inhibited.Overall,this study demonstrated that LCFS-LCEO-NEs function as multifunctional preservatives through multiple integrated mechanisms,including structural encapsulation,enhanced antioxidant activity,additive antibacterial effects,and browning enzyme inhibition.Thus,they offer a sustainable and innovative strategy for the postharvest management and quality control of wild vegetables.展开更多
基金supported by the Jilin Province Science and Technology Plan Project(20230402032GH)。
文摘Lactiplantibacillus plantarum 104,which was previously screened in the laboratory,has been confirmed to have the effect of lowering lipids and regulating intestinal microbial homeostasis.However,the mechanism of action of its fermentation supernatant in alleviating metabolic disorders is unclear.L.plantarum 104 cell-free supernatant(LP104s)was fed to high-fat diet C57BL/6N mice for 8 weeks.The intervention of LP104s increased the concentration of conjugated bile acids in the ileum,especially taur-α/β-muricholic acid sodium salt(T-α-MCA or T-β-MCA),inhibited intestinal farnesoid X receptor(FXR)-related signaling pathways.LP104s reduced cholesterol levels by increasing the synthesis of hepatic cholic acid(CA),chenodeoxycholic acid(CDCA),and the excretion of bile acids in feces.Moreover,Western blotting results showed that TLR2/NF-κB signaling pathway expression was inhibited.In addition,16S r RNA sequencing results showed that LP104s regulated the relative abundance of bacteria associated with inflammatory response and obesity(Prevotella,Ruminococcus,and Clostridium).Therefore,this paper further elaborates the role of gut microbiology and bile acids in improving metabolism from the perspective of secondary bile acids and intestinal chronic inflammation and also lays a theoretical foundation for the next step in the development of fermentation products of this strain.
基金Supported by the National Natural Science Foundation of China,No.81570489and the Youth Project of National Natural Science Foundation of China,No.81900487.
文摘BACKGROUND Bacillus subtilis(B.subtilis),Enterococcus faecium(E.faecium),and Enterococcus faecalis(E.faecalis)are probiotics that are widely used in the clinical treatment of irritable bowel syndrome(IBS).Whether the supernatants of these three probiotics can improve gastrointestinal sensation and movement by regulating the serotonin transporter(SERT)expression needs to be clarified.AIM To investigate whether B.subtilis,E.faecium,and E.faecalis supernatants can upregulate SERT expression in vitro and in vivo.METHODS Caco-2 and HT-29 cells were stimulated with probiotic culture supernatants for 12 and 24 h,respectively.A male Sprague-Dawley rat model of post-infectious irritable bowel syndrome(PI-IBS)was established and the rats were treated with phosphate-buffered saline(group A)and three probiotics culture supernatants(groups B,C,and D)for 4 wk.The levels of SERT were detected by quantitative PCR and western blotting.RESULTS The levels of SERT at post-treatment 12 and 24 h were significantly elevated in Caco-2 cells treated with B.subtilis supernatant compared with those in the control group(aP<0.05).Those levels were markedly upregulated in Caco-2 cells stimulated with E.faecium and E.faecalis supernatants at 24 h(aP<0.05).In addition,SERT expression in groups B,C,and D was significantly higher than that in group A in the 2nd wk(aP<0.05).Increased SERT expression was only found in group D in the 3rd wk(aP<0.05).However,there was no significant difference in SERT expression between the groups in the last week(P>0.05).CONCLUSION The supernatants of B.subtilis,E.faecium,and E.faecalis can upregulate SERT expression in intestinal epithelial cells and the intestinal tissues in the rat model of PI-IBS.
基金Project(2011TT2057)supported by Science&Technology Department of Hunan Province,China
文摘A novel technology using Fe powder as reducing agent for Ge and Cu recovery from precipitating vitriol supernatant in Zn hydrometallurgical plant was investigated. The results show that reaction time, temperature, agitation speed, initial pH value of solution and the amount of reducing Fe have significant effects on recovering Ge and Cu, and the optimum process operating parameters are established as follows： time 120 min, initial pH value 1.5, the dosage of reducing Fe powder 4 g/L, agitation speed 600 r/min and temperature 80 °C. Under these experimental conditions, the recovery ratios of Ge and Cu from precipitating vitriol supernatant in Zn hydrometallurgical plant can reach 96% and 100%, respectively. The content of Ge in the reduced residue reaches up to 2.06% （mass fraction）, indicating that the separation and enrichment of Ge from the Zn sulfate solution is realized. The grade of Ge and Cu can reach up to 4.88% and 56.75%, respectively, when the reduced residue is further processed.
基金the National Natural Science Foundation of China,No.81570489
文摘AIM To evaluate the effect of Lactobacillus rhamnosus GG supernatant(LGG-s) on the expression of serotonin transporter(SERT) in rats with post-infectious irritable bowel syndrome(PI-IBS).METHODS Campylobacter jejuni 81-176(1010 CFU/m L) was used to induce intestinal infection to develop a PI-IBS model. After evaluation of the post-infectious phase by biochemical tests, Dn A agarose gel electrophoresis, abdominal withdrawal reflex(AWR) test, and the intestinal motility test, four PI-IBS groups received different concentrations of LGG-s for 4 wk. The treatments were maintained for 1.0, 2.0, 3.0 or 4.0 wk during the experiment, and the colons and brains were removed for later use each week. SERT m Rn A and protein levels were detected by real-time PCR and Western blot, respectively.RESULTS The levels of SERT m Rn A and protein in intestinal tissue were higher in rats treated with LGG-s than in control rats and PI-IBS rats gavaged with PBS during the whole study. Undiluted LGG-s up-regulated SERT m Rn A level by 2.67 times compared with the control group by week 2, and SERT m Rn A expression kept increasing later. Double-diluted LGG-s was similar to undiluted-LGG-s, resulting in high levels of SERT m Rn A. Triple-diluted LGG-s up-regulated SERT m Rn A expression level by 6.9-times compared with the control group, but SERT m Rn A expression decreased rapidly at the end of the second week. At the first week, SERT protein levels were basically comparable in rats treated with undiluted LGG-s, double-diluted LGG-s, and triplediluted LGG-s, which were higher than those in the control group and PBS-treated PI-IBS group. SERT protein levels in the intestine were also comparable in rats treated with undiluted LGG-s, double-diluted LGG-s, and triple-diluted LGG-s by the second and third weeks. SERT m Rn A and protein levels in the brain had no statistical difference in the groups during the experiment.CONCLUSION LGG-s can up-regulate SERT m Rn A and protein levels in intestinal tissue but has no influence in brain tissue in rats with PI-IBS.
基金supported by the Major State Science and Technology Water Projects (No. 2013ZX07202010)
文摘N-dodecanoyl homoserine lactone（C（12）-HSL）was detected in the supernatant of an anammox granular sludge reactor（AGSR）.C（12）-HSL could enhance the specific anammox activity of anammox biomass.Adding C（12）-HSL-containing AGSR supernatant into the continuously stirred tank reactors reduced the start-up time of the anammox process from80 to 66 days.Moreover,the nitrogen loading rate was also enhanced to 1.6 times that of the control reactor.AHLs could increase the secretion of extracellular polymeric substances and anammox obtained better enrichment with the addition of AHLs-containing AGSR supernatant.Denaturing gradient gel electrophoresis analysis further revealed that AHLs played a role in mediating microbial community parameters.In conclusion,adding AHL-containing supernatant could be an effective and economical way to accelerate the start-up of anammox.
基金Project(2006BAD18B02) supported by the 11th Five-Year Plan of National Key Technology R&D Program of ChinaProject(07006B) supported by Youth Fund of Central South University of Forestry and Technology,ChinaProject(080929) supported the Education Fund of Hunan Province,China
文摘The rheological properties in the supernatant of peach gum from Prunnus dulcis were discussed in order to provide more scientific technical parameters and references for developing peach gum as a kind of medicinal gum.The rheological properties in the supernatant of peach gum were comparatively studied in different material ratios,temperatures,shaking times,pH values and salinities.The results show that,1) the mathematical model of shear rate with material ratio and shear stress is Y=0.069X12+0.035X2 -1.174,R2=0.942;2) the mathematical model of shear rate with temperature and shear stress is Y=4.936X12+0.023 2X2-1.688,R2=0.937;3) the mathematical model of shear rate with shaking time and shear stress is Y=0.005 192 X13-0.140 73X12+1.249 045X1+ 0.036 546 X2-3.644 29,R2=0.954 3;4) the effects of pH value on the rheological properties in the supernatant of peach gum are comparatively complicated with a varying range of 3-11 and the shear rate shows a change trend of saddle model;5) the mathematical model of shear rate with the concentration of NaCl and shear stress is Y=-0.037 44X1+0.012 93 X2,R2=0.998;6) the mathematical model of shear rate with the concentration of CaCl2 and shear stress is Y=0.025 789X1+0.016 19X2,R2 =0.999;and 7) the mathematical model of shear rate with the concentration of sorbic acid potassium and shear stress is Y=0.079 5X1+0.017 3X2,R2=0.998.The results show that the material ratio,temperature,shaking time,pH value significantly affect the rheological properties in the supernatant of peach gum,and the concentrations of NaCl and CaCl2 also significantly affect the rheological properties expect the concentration of sorbic acid potassium.
基金supported by the Mega-Projects of Science Research for Water Environment Improvement (No. 2012ZX07205-001)
文摘A combined nitritation–anammox reactor was developed to treat the digestion supernatant under various C/N ratios. Due to the difficulties for heterotroph to utilize the refractory organics, the reactor presented relatively stable performance with increasing supernatant addition. Nevertheless, the adverse effects of supernatant would accumulate during the long-term operation and thus weakened the activity and shock resistance of microbes,which further led to the gradual decrease of reactor performance after 92 days＇ operation.Under this circumstance, supernatant with volatile fatty acids（VFAs） residuals was further introduced into the reactor to investigate the performance of combined nitritation–anammox process with VFA addition. With the appearance of VFAs, the nitrogen removal performance gradually restored and the reactor finally achieved stable and efficient performance with C/N ratio of 0.35. The VFA residuals within 150 mg/L in the supernatant served as the extra electron donors and stimulated the heterotrophic denitrification process, which was vital for the enhancement of reactor. The nitrogen removal rate and total nitrogen removal efficiency reached 0.49 kg N/（m^3·day） and 88.8% after 140 days＇ operation, respectively. The combined nitritation–anammox reactor was proved suitable to treat digestion supernatant.
基金This project was supported by a grant from National Natural Sciences Foundation of China(No.39770 76 7)
文摘The bioactivities of culture supernatants from retroviral packaging cells carrying the mouse Fas ligand (mFasL) gene was investigated. FasLcDNA was cloned into PLXIN with an internal ribosome entry site to link two cistrons through gene recombination technology, PLXIN and the recombinant vector PLFIN were separately transfected into PA317 retrovirus packing cell line by lipofectamine 2000, and the resistant clones were selected with G418 selective medium. The integration of genome DNA was assayed by genomic DNA PCR. NIH3T3 cells were transduced by the culture supernatants from PA317 carrying the mFasLcDNA gene, and were selected with G418 selective medium, so as to select the PLFIN-PA317 clone capable of producing higher titer of supernatants. The levels of mFasL protein on NIH3T3 cells membrane were assayed by flow cytometry (FCM). The biological activity of mFasL on NIH3T3 cells membrane was investigated by the inducing apoptosis of Fas + Yac-1 cells co-cultured with NIH3T3 cells expressing Fas ligand. To explore the direct mFasL cytotoxicity of culture supernatants from retroviral packaging cells carrying the mFasL gene, the culture supernatants from PLFIN-PA317 and PLXIN-PA317 were separately co-cultured with Yac-1 cells in parallel. The recombinant PLFIN was successfully constructed. The highest titer of supernatants from twelve resistant clones was 8.5×10 5 colony-forming-unit (CFU)/ml. The NIH3T3 cells transfected by above supernatants had a higher level of mFasL (53.81±6.9 %), and significantly induced the apoptosis of Fas + Yac-1 cells (56.78±4.5 %), as both were cocultured for 5 h at 1∶1 ratio, whereas it is 7.08±3.4 % in control group (P<0.01). Supernatant from PLFIN-PA317 could also directly induce the apoptosis of Yac-1 within 5 h of incubation. Thus, the culture supernatants from PLFIN-PA317 possessed both infectivity and cytotoxicity of mFasL.
文摘The proliferation of splenocytes from health adults was induced by anti-CD3 McAb and IL-2.The proliferative potential of the splenocytes and antitumor activity of their culture supernatants of splenocytes were studied.The results showed that anti-CD3 McAb not only enhanced the proliferation of the splenocytes directly,but also enhanceil that of induced by IL-2.Their enhancing effect was more significant when the incubation time in vitro was prolonged.The culture supernatants of anti-CD3 and IL-2 induced splenocytes also had the antitumor activity and enhancing capability to the antitumor activity of LAK tells.The results suggested that LAK cells could secret lymphokine,and this effect would be synergically promoted when anti-CD3 and IL-2 were simultaneously used.
文摘Phosphorus is an irreplaceable and depletable element. Furthermore, it has an almost one-way circulation on earth, so it is necessary to close the phosphorus cycle loop. Phosphorus could be recovered as struvite, which is a good slow-released fertilizer for agriculture. The supernatant of anaerobic digestion used to treat sludge from wastewater treatment plant is one main source from which phosphorus can be recovered. Studies have proven that phosphorus recovery from digester supematant is a feasible choice to preserve phosphorus rock technically and economically. A modified ＂PHOSNIX＂ P-recovery process was applied under the operating conditions of a 9.0 pH value and a 1.8 mg： P ratio with the influent of the centrate coming from the sludge centrifuge of the Songjiang Wastewater Treatment Plant in Shanghai. More than 80% influent phosphorus was recovered as struvite. Crystal products with good purity and low heavy metal content were gained. The largest crystal had a length of up to 0.26 mm. It was found in our study that the reaction time did not play an important role in crystal growth. Therefore, the optimization of the reaction condition for crystal growth should be examined in future study.
文摘Aspergillus parasiticus, a common fungal contaminant in food, produces aflatoxin B1, which is classified as human carcinogen. Kefir is an ancient fermented beverage obtained by the fermentation of different substrates with kefir grains. A very important waste produced by the dairy cheese industry is the whey permeate, which nowadays is a strong ambient contaminant. The aim of this work was to assess the effect of whey permeates fermented with kefir grains against A. parasiticus growth, aflatoxin B1 biosynthesis, and the kefir microorganisms protection against the cell damage produced by aflatoxin B1. It was observed that kefir-cell-free-supernatants (CFS) produced fungal inhibition. A fungicidal effect was observed with 65% v/v of CFS in the culture medium (final pH 4.55 and total undissociated lactic and acetic acid concentration 34.08 mM). Under these conditions, aflatoxin production was not detected. Finally, it was found that non-viable kefir microorganisms protected HepG2 cells from the damage produced by aflatoxin B1.
文摘Background Our previous study showed the 150 mg/mL fetal cardiac supernatant （FCS） could induce differentiation of BMSCs into cardiomyocye-like cells without cardiomyocyte touch,but differentiation efficiency is not high enough.Inhibition of glycogen synthase kinase-3 enhanced the proliferation and survives of stem cells.We tested if 6-bromoindirubin-3-oxime （BIO,glycogen synthase kinase-3 inhibitor） enhances the effects of FCS on differentiation of BMSCs and explore the growth factors in FCS.Methods BMSCs were isolated from the femur and tibia of four-week-old male Sprague-Dawley rats and co-cultured with FCS （150 mg/mL） that was made from fetal hearts from nineteen-day pregnant Wistar rats.BIO with different concentration （0,1,10,and 100 nM） was introduced in culture dishes.Transforming growth factor beta 1 （TGF-β1）,bone morphogenetic protein 2 （BMP-2） and Akt in cardiac supernatant and culture medium were assayed with ELISA methods.Results After co-culturing with FCS,beating myotubes were observed in 25.9 % BMSCs dishes after 1 to 2 weeks＇ culture.The levels of TGF-β1 and BMP-2 in FCS concentrations were no more than that in young and adult cardiac supernatant.All BIO groups significantly enhanced the effects of FCS on differentiation of BMSCs into the cardiomyocyte-like cells （1 nM,83 %;10 nM,73 %;100 nM,100 %）.Akt levels were higher in BMSCs cultural medium with FCS.Conclusions FCS could induce the differentiation of BMSCs into the cardiomyocyte-like cells.TGF-β1 and BMP-2 might not play a role in the differentiation of BMSCs induced by FCS.BIO enhanced the effects of FCS on the differentiation of BMSCs into cardiomyocyte-like cells,which might involve the Akt pathway.
文摘[Objective] Pseudomonas as one of the dominant spoilage bacteria highly form biofilms in chilled meat products and processing environment when contaminating single or mixed with other species.This study aims to investigate the antibiofilm properties of the cell-free supernatants(CFSs) of three Bacillus species isolated from fermented food and rice seeds on Pseudomonas lundensis(PL) or and Acinetobacter johnsonii(AJ) as mono-or dual-species.[Methods] Biofilm biomass,extracellular polymeric substances(EPSs),and biofilm structure were measured by crystal violet staining,spectrophotometry,confocal laser scanning microscopy(CLSM),respectively,as well as transcription of biofilm-related genes determined by qPCR.[Results] The CFSs of Bacillus amyloliquefaciens ZG08,B.velezensis B5,and B.subtilis YB11 inhibited the biofilm formation of PL and AJ without affecting their growth.The treatment with 50% CFSs of ZG08 and B5 decreased the cell viability of two biofilms by 12.73%–21.04%,which was higher than that of YB11(0.15%–4.38%).The inhibition rates of 50% CFSs of the three strains were 59.75%–79.59% against the PL biofilm and 63.62%–78.57% against the biofilm of PL+AJ,in which the CFS of YB11 had weaker activity.The content of exopolysaccharides and exoprotein in the two biofilms treated with these CFSs were reduced by 53.77%–73.30% and 54.84%–62.38%,respectively.The treatment with the three CFSs also reduced the adhesive cells,loosened biofilm structures,and thinned their thickness by 57.63%–74.49% and 60.43%–64.64%,respectively.Moreover,the CFSs of ZG08 and B5 effectively eradicated by 41.77%–69.79% against the mature biofilms of PL and PL+AJ,compared to weak activity of YB11.In addition,the antibiofilm activities of the three CFSs were stable under four enzyme digestion and heating conditions.Compared with the control,the CFSs of ZG08 and B5 significantly down-regulated the expression of six biofilm-related genes,lapA,alg44,pelG,luxR,wspR,and rpoS.[Conclusion] The CFSs of ZG08 and B5 have strong antibiofilm activities against PL and AJ as mono-or dual-species.
文摘The biotechnological industry faces a crucial demand for novel bioactive compounds,particularly antimicrobial agents,to address the rising challenge of bacterial resistance to current available antibiotics.Traditional strate-gies for cultivating naturally occurring microorganisms often limit the discovery of novel antimicrobial producers.This study presents a protocol for targeted selection of bacterial strains using the supernatant of Paenibacillus el-gii,which produces abundant signal molecules and antimicrobial peptides.Soil samples were inoculated in these enriched culture media to selectively cultivate bacteria resistant to the supernatant,indicating their potential to produce similar compounds.The bacterial strains isolated through this method were assessed for their antibac-terial activity.In addition,the functional annotation of the genome of one of these strains revealed several gene clusters of biotechnological interest.This study highlights the effectiveness of using this approach for selective cultivation of microorganisms with potential for biotechnological applications.
基金financially supported by the Key Research Projects of the Science and Technology Department of Henan Province(No.222102110352)the Doctor fund project of Zhengzhou University of Light Industry(No.2022BSJJZK08).
文摘This research aimed to study the evolution of ATP-related compounds in dry-cured ham and to assess their suitability as chemical markers of food contamination.A rapid high-performance liquid chromatography(HPLC)method was developed for the analysis of five ATP-related compounds namely,ATP,ADP,AMP,hypoxanthine,and Ino in sliced dry-cured ham.Moreover,a positive correlation between ATP content and microbial load was found in ham during storage.In addition,the method developed herein was employed to quantify ATP-related compounds in sliced dry-cured ham wrapped in a novel antibacterial packaging film containing the cell-free supernatant(CFS)of a probiotic Lactiplantibacillus plantarum strain.The contents of ATP-related compounds in ham samples wrapped in the antibacterial packaging film were lower than in control samples during the 7 days of storage(181 vs 269 mg/kg on day 2;247 vs 286 mg/kg on day 5;272 vs 297 mg/kg on day 7).Thus,the evaluated CFS could be considered in packaging material applications for the preservation of sliced ham.This study presents an effective method to assess the quality of sliced ham,which might also contribute to the adoption of active packaging in the food industry.
基金funding from the National Natural Science Foundation of China(U20A2066)the Key Project of Zhejiang Gongshang University“Digital+”Discipline Construction+2 种基金(SZJ2022A006)the National Key R&D Program of China(2022YFD2100701)the“Sannongjiufang”Research Joint Project of Zhejiang Province(2023SNJF017).
文摘Helicobacter pylori,a carcinogenic bacterium,poses a significant health risk and raises concerns about food safety,particularly through transmission via dairy products.Lactic acid bacteria(LAB)fermentation supernatants have shown antibacterial activity against H.pylori,but their metabolites and mechanisms remain unclear.In this study,the cell-free fermentation supernatant of Latilactobacillus sakei LZ217(LZ217-CFS)exhibited superior antibacterial effects compared to colloidal bismuth subcitrate,inducing H.pylori apoptosis with nucleic acid and protein leakage.Metabolomics,network pharmacology,and molecular docking identified key antibacterial metabolites(such as L-glyceraldehyde and niacin)in LZ217-CFS and their targets.The results suggested that the activities of two enzymes,IMP dehydrogenase and GTP cyclohydrolase II identified as the primary targets,were significantly inhibited by LZ217-CFS.Moreover,LZ217-CFS significantly affected H.pylori’s central carbon metabolism,purine metabolism,and riboflavin metabolism.This discovery unveils a novel mechanism for H.pylori inhibition,supporting LAB fermentation supernatants’potential as natural preservatives in food safety,enhancing quality.
基金supported by the Jilin Provincial Scientific and Technological Development Program(No.20230202049NC).
文摘Ferns,a common class of wild edible plants(WEPs),are highly nutritious,but they are prone to rapid spoilage.Thus,developing effective preservation methods for ferns is necessary.Initially,this study confirmed that Pseudomonas spp.primarily causes the decay of ferns.Subsequently,the potential of combining the cell-free supernatant(CFS)of lactic acid bacteria with natural aromatic compounds as a green preservative agent was explored.In particular,this study focused on the combined use of Lactobacillus paracasei Z21 CFS(LCFS)and thymol(LCFS-T)to target spoilage bacteria Pseudomonas aeruginosa and Pseudomonas putida,and to elucidate their antibacterial and antibiofilm mechanisms.Results indicated that LCFS-T significantly enhanced bactericidal activity while reducing dosages compared with either agent alone.Bacterial content leakage,cell membrane permeability assays,and scanning electron microscopy analysis indicated that LCFS-T caused remarkable changes in cell membrane permeability and integrity.The swimming motility assay and light microscopy observation of biofilms demonstrated that the antibiofilm activity of LCFS-T was due to the inhibition of flagellar motility.Notably,treatment with LCFS-T effectively delayed spoilage in ferns,thereby extending their shelf life by an additional 9 days.Compared with the control group,the ferns treated with LCFS-T maintained their color,texture,and overall quality.This study highlights LCFS-T as a promising natural food preservative,providing an effective strategy to mitigate food safety risks associated with WEPs and to support the development of sus-tainable preservation methods.
基金supported by grants from the Major Science and Technology Fund of Guangxi Province(AB23026035)the Hubei Province Health and Family Planning Scientific Research Project(No.WJ2023M168).
文摘Aflatoxin,a harmful secondary metabolite produced by Aspergillus flavus and Aspergillus parasiticus,poses a significant risk to human health and food safety.Therefore,the development of safe and environmentally friendly techniques for controlling A.flavus and its aflatoxin production is imperative.In this study,Bacillus velezensis 906 cell-free fermentation supernatant(CFS)inhibited the germination of A.flavus spores and myce-lium growth.Scanning electron microscopy and fluorescence microscopy revealed that CFS altered cell morphology and damaged the cell membrane of A.flavus leading to cell death.Fourier transform infrared spectroscopy indicated changes in the functional groups of A.flavus filaments treated with CFS.The trend in ergosterol content demonstrated that CFS effectively inhibited the normal growth of A.flavus cell membranes.The CFS exhibited remarkable efficacy in degrading aflatoxin B1(AFB1),achieving a degradation rate of up to 60%after 48 h of interaction.The addition of 0.2 mg/mL Cu^(2+)or Fe^(3+)metal ions to CFS significantly increased the degradation rate of AFB1 up to 90%.Furthermore,the analysis indicated that the active components responsible for AFB1 degradation might be heat-resistance and exhibit resistance to protease K.These findings underscore the potential of CFS as a green,safe,and economically viable strategy for controlling aflatoxin production by A.flavus,offering promising prospects for mitigating mold contamination in food and feed applications.
基金support from the Jilin Provincial Scientific and Technological Development Program(No.20230202049NC).
文摘This study reports the development of a novel oil-in-water nanoemulsion system composed of Lactobacillus plantarum SC21 cell-free supernatant(LCFS),Litsea cubeba essential oil(LCEO),and soy lecithin(SL).Through systematic characterization,this study revealed that the nanoemulsions exhibited a uniform spherical morphology,stable dispersion,and minimal aggregation.These findings demonstrated the formation of a robust interfacial structure,likely via molecular interactions such as hydrogen bonds and electrostatic forces.The encapsulation of bioactive compounds within this system significantly enhanced their functional performance.Specifically,LCFS-LCEO nanoemulsions(LCFS-LCEO-NEs)showed improved antioxidant activity and stronger antibacterial effects against common spoilage microorganisms(Pseudomonas aeruginosa and Pseudomonas putida)in fiddlehead ferns than LCFS and LCEO alone,and it outperformed the simple physical mixture of LCFS and LCEO,highlighting the crucial role of the nanoencapsulation process.When applied to fiddlehead ferns during storage at 4℃,LCFS-LCEO-NEs effectively hindered quality loss by delaying browning,senescence,and moisture loss,thereby extending the postharvest shelf life to 24 days.Additionally,the textural properties and key nutritional components of fiddlehead ferns were also maintained during refrigerated storage,and key browningrelated enzymes such as polyphenol oxidase and peroxidase were inhibited.Overall,this study demonstrated that LCFS-LCEO-NEs function as multifunctional preservatives through multiple integrated mechanisms,including structural encapsulation,enhanced antioxidant activity,additive antibacterial effects,and browning enzyme inhibition.Thus,they offer a sustainable and innovative strategy for the postharvest management and quality control of wild vegetables.
