Probiotics and Antimicrobial Proteins最新文献

The study aimed to evaluate the effects of supplementation with Lacticaseibacillus casei CSL3 in Swiss mice immunosuppressed with cyclophosphamide on immunological, biochemical, oxidative stress, and histological parameters. The animals were distributed into four groups (control, CSL3, cyclophosphamide, and CSL3 + cyclophosphamide), where two groups were treated with L. casei CSL3 (10 log CFU mL^-1) for 30 days, and two groups received chemotherapy (days 27 and 30-total dose of 250 mg kg^-1). Counts of lactic acid bacteria (LAB) and bile-resistant LAB in stool samples; blood count (erythrogram, leukogram, and platelets); serum total cholesterol levels; catalase enzyme activity; and thiobarbituric acid reactive substances (TBARS) levels in liver, kidney, and brain; IL-4 expression; IL-23, TNF-α, NF-κβ in the spleen; and histological changes in the liver, kidneys, and intestine were evaluated. The CSL3 + cyclophosphamide group showed a significant increase in bile-resistant LAB counts in feces (p = 0.0001), leukocyte counts, and expression of IL-23, TNF-α, and NF-κβ (p < 0.05) significantly reduced total cholesterol levels (p = 0.001) and protected liver damage of supplemented animals. For oxidative stress damage, the bacterium did not influence the results. It is concluded that the bacterium is safe at a concentration of 10 log CFU mL^-1 and has probiotic potential due to its positive influence on the immune response and lipid metabolism.

The contamination of food with Listeria monocytogenes threatens food safety and human health, and developing a novel, green, and safe antimicrobial substance will offer a new food preservation strategy. FengycinA-M3 is a novel lipid peptide with low cytotoxicity and resistance and has effective antibacterial activity against L. monocytogenes with a minimum inhibitory concentration (MIC) of 4 µg/mL. Further combined transcriptomics and proteomics analysis yielded 20 differentially expressed genes (DEGs). The MICs of the combined use of FengycinA-M3 and Cefalexin on L. monocytogenes were further determined as FengycinA-M3 (2 µg/mL) and Cefalexin (8 µg/mL) using the checkerboard method. In addition, FengycinA-M3 was found to play a role in delaying pork deterioration. This study explored the inhibitory effect of FengycinA-M3 on L. monocytogenes and its mechanism of action. FengycinA-M3 interacted with penicillin-binding protein 2B on the cell membrane of L. monocytogenes, destroying the permeability of the membrane, causing cell membrane rupture, thereby inhibiting the growth of L. monocytogenes. Overall, FengycinA-M3 is a promising candidate for preventing the emergence and spread of L. monocytogenes with potential applications in food processing.

The increase in the prevalence of asthma, particularly in urban communities, has encouraged investigations into preventive strategies. The hygiene theory proposes that early exposure to infections and unhygienic conditions during childhood influences immune system development, potentially protecting against allergic diseases. The mechanisms involved are related to alterations in the intestinal microbiota, such as with probiotics. This study aimed to evaluate the preventive effect of Lacticaseibacillus rhamnosus, Lacticaseibacillus paracasei, and Bifidobacterium animalis ssp. lactis, administered isolated or in combination, at various concentrations, on asthma in an animal model. Mice received two concentrations (1 × 10⁹ and 1 × 10¹⁰ CFU/ml) of three probiotics, isolated and in combination, over 26 consecutive days, initiating 10 days before sensitizing and challenging with ovalbumin. In vivo bronchial hyperresponsiveness and airway and lung inflammation were assessed. The administration of L. paracasei, L. rhamnosus, and B. animalis spp. lactis in different concentrations, isolated or in combination, did not reduce hyperresponsiveness and airway and lung inflammation. As probiotic effects are strain and dose-dependents, specific studies are necessary to assess the effect of different probiotic strains, doses, and regimes.

Eubacterium rectale (E. rectale) has the ability to attenuate systemic and intestinal inflammation. Its naturally secreted membrane vesicles (MVs) likely play a crucial role in this process. The objective of this study is to investigate the anti-inflammatory effects of E. rectale and its membrane vesicles (MVs). An inflammation model was established by inducing an inflammatory response in Raw 264.7 cells using lipopolysaccharide (LPS). Subsequently, the cells were pre-treated with E. rectale and its MVs, and the expression levels of IL-1β, IL-6, TNF-α, and IL-10 in the cells were then detected using RT-qPCR. ELISA was used to measure the secretion levels of IL-1β, while western blot analysis was employed to assess the expression of key proteins in the IL-1β pathway, specifically ASC, Caspase 1, and NLRP3. The results revealed that both E. rectale and its MVs significantly reduced the expression of the inflammatory cytokines IL-1β and TNF-α in Raw 264.7 cells, which were induced by LPS. Additionally, they markedly upregulated the expression of the anti-inflammatory cytokine IL-10 and suppressed IL-1β expression via the NLRP3-Caspase 1-ASC signaling pathway. These findings suggest that E. rectale, through its membrane vesicles, can attenuate LPS-induced NLRP3 inflammasome activation, thereby mitigating the inflammatory response in Raw 264.7 cells.

Irritable bowel disease (IBD), also known as ulcerative colitis and Crohn's disease, is a chronic inflammatory disorder affecting millions of people worldwide. Herein, nano-encapsulated multi-strain probiotics formulation, comprising Bifidobacterium breve DSM24732 and B. coagulans SANK 70258 and L. plantarum DSM24730 (BBLNPs) is used as an effective intervention technique for attenuating IBD through gut microenvironment regulation. The efficacy of the prophylactic role of BBLNPs in alleviating injury induced by dextran sulfate sodium (DSS) was evaluated by assessing oxidative and inflammatory responses, levels of short-chain fatty acids (SCFAs) and their regulation on GPR41/43 pathway, expression of genes related to tight-junctions and autophagy, immunohistochemistry of IL1β and GPR43, and histological examination of inflamed colonic tissue. The severity of clinical signs and paracellular permeability to FITC (fluorescein isothiocyanate)-labeled dextran was significantly decreased after BBLNP treatment. Reduction of oxidative stress-associated biomarkers (MDA, ROS, and H₂O₂) and acceleration of antioxidant enzyme activities (SOD, CAT, and GSH-Px) were noted in the BBLNP-treated group. Subsiding of inflammatory markers (TNF-α, IL-18, IL-6, TRL-4, CD-8, NLRP3, and caspase 1) and upregulation of tight-junction-related genes (occludin and JAM) was detected in BBLNPs. Administration of BBLNPs remarkably resulted in a higher level of SCFAs which parrel with colonic upregulation of GPR41 and GPR43 expression compared to DSS-treated rats. Notable modulation of autophagy-related genes (p62, mTOR, LC3, and Beclin-1) was identified post BBLNP treatment. The mRNA expressions of p62 and mTOR were significantly downregulated, while LC3 and Beclin-1 were upregulated after prophylactic treatment with BBLNPs. Immune-stained labeled cells showed lower expression of IL-1β and higher expression levels of GPR43 in BBLNPs compared to the DSS-induced group. The intestinal damage caused by DSSwas effectively mitigated by oral BBLNP treatment, as supported by the restoration of healthy colonic tissue architecture. The findings suggest that BBLNPs have a promising avenue in the remission of IBD by modulating inflammation, oxidative stress, microbial metabolites such as SCFAs, and autophagy.

This study evaluated the probiotic characteristics of Lactiplantibacillus plantarum strains, revealing strong acid and bile salt tolerance and significant adhesion to HT-29 cells. In addition, the anti-melanogenic and antioxidant properties of their cell-free supernatants (CFS) were investigated in vitro. Melanogenesis assays were performed in α-melanocyte-stimulating hormone (α-MSH)-stimulated B16F10 melanoma cells, while antioxidant activity was evaluated in H₂O₂-stimulated HaCaT keratinocytes. CFS treatment inhibited melanin synthesis, tyrosinase activity, and expression of melanogenesis-related genes, including MITF, Tyr, Trp1, and Trp2. These effects were attributed to the suppression of cAMP-response element-binding protein (CREB)/microphthalmia-associated transcription factor (MITF) and mitogen-activated protein kinase (MAPK; ERK, JNK, and p38) signaling pathways. Antioxidant activity was observed via nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway activation, resulting in elevated levels of downstream targets such as HO-1, NAD(P)H:quinone oxidoreductase (NQO1), and thioredoxin reductase 1 (TXNRD1). High-performance liquid chromatography (HPLC) analysis identified lactic acid and acetic acid as the primary metabolites in the CFS associated with these biological effects. These findings suggest that culture supernatants derived from probiotics may serve as natural agents with skin-whitening and antioxidant properties, supporting their potential application in food, pharmaceutical, and cosmetic industries.

In this study, four lactic acid bacteria (LAB) strains demonstrating ciprofloxacin, bile salt, gastric fluid, and intestinal fluid tolerance as well as adhesion ability to Caco-2 and HT-29 cells were used to improve and recover the intestinal flora disorders caused by ciprofloxacin, among which, Lactobacillus brevis 505 exhibited excellent adhesion ability to two kinds of cells and colonization ability to mouse intestinal. After ciprofloxacin treatment, certain recovery effect on cecum caused by ciprofloxacin in the mice was found during natural recovery (group 5C2), but it was challenging to fully restore the intestinal integrity to the initial level. After L. brevis 505 intervention (group 5C5), the intestinal damage to the colon and ileum caused by ciprofloxacin in mice was significantly alleviated; the recovery effect was better than that of natural recovery. Additionally, L. brevis 505 could effectively regulate INF-γ, sIgA, and RegIIIγ increase induced by ciprofloxacin. Shannon and Simpson index of the intestinal flora of mice in 5C5 group were higher than those in other group, the relative abundance of Bifidobacterium and Lactobacillus in the mice in 5C5 group was increased, indicating that LAB can better restore the structure and abundance of intestinal microflora. Consequently, L. brevis 505 shows promise as a probiotic for gut microbiota restoration and rebuilding during antibiotic therapy.

Probiotics play an important role in animal growth, immunity, and gut microbial balance and are now widely used in agriculture, food, and medicine. This study analysed the effects of different concentrations of Tibetan sheep compound probiotics on the immunity, tissue morphology, and intestinal microbiota of mice using histological, molecular, and 16S rRNA techniques. The results showed that the composite probiotics sourced from Tibetan sheep improved the growth performance of mice, increased the length of small intestinal villi and mucosal thickness, and enhanced the intestinal barrier function of mice. DZ-L and DZ-M significantly increased the mRNA expression levels of ZO-1, Occludin, and Claudin-1 mRNA. They also up-regulated IL-10 and TNF-β, and down-regulated TNF-α, IL-1β, and IL-8. The immune function of mice was enhanced, with DZ-M treatment having an extremely significant effect, while the effect of DZ-H treatment was slightly lower compared to DZ-L and DZ-M. In addition, the composition and diversity of the intestinal microbiota were modulated, and at the phylum level, the relative abundance of Firmicutes was higher in the DZ-M group, the relative abundance of Desulfobacterota, Actinobacteriota, and Patescibacteria was reduced in the probiotic complex group, and the relative abundance of Verrucomicrobiota was higher. At the genus level, the relative abundance of Muribaculaceae was higher in the DZ-L and DZ-M groups, and the relative abundance of Lachnospiraceae_NK4A136_group in the DZ-H group; and the relative abundance of Bacteroides and Roseburia in the composite probiotic group. This study can improve the reference for the development of new green feed additives instead of antibiotics, which will also further promote the development of the livestock industry.

Though numerous bacteria have been used as probiotics by industries, at present, Saccharomyces boulardii and Saccharomyces cerevesiae are the only yeast probiotics which are industrially exploited. In view of this, yeast probiotics were isolated from traditional fermented foods and products collected from different parts of Karnataka, India. In this work, we have studied the probiotic attributes of ten yeast isolates isolated from different traditionally fermented foods and products. About 73 yeast isolates were initially isolated by serially diluting the samples and plating on the Potato Dextrose Agar (PDA) plates. The spot assay was performed to screen the yeast isolates against test pathogens. Ten isolates were selected based on their significant antimicrobial activity. These isolates were subjected to biochemical characterization and then assessed for probiotic properties. The ability of probiotics to endure at pH 2.0 and tolerate bile conditions (0.3%) are crucial attributes for the survival in the gastrointestinal tract (GIT). The yeast isolates were also assessed for cell surface hydrophobicity and autoaggregation capabilities. All the ten isolates showed endurance in GIT tract and > 40% of adhesion. The study further examined cholesterol assimilation, antioxidant and antagonistic properties of the yeasts. Subsequently, the molecular characterization was performed by isolating the DNA of yeast isolates by phenol-chloroform method and identified molecularly through sequencing of D1/D2 regions. The isolates tested negative for gelatinase and DNase and were non-haemolytic indicating they are safe for consumption. Among ten isolates, Meyerozyma guillermondii (MYSY23), Meyerozyma caribbica (MYSY22) and Meyerozyma guillermondii (MYSY19) showed significant results for all probiotic and functional characteristics with greater than 65% survivability in GIT tract and > 50% of antagonistic activity against test pathogens and also proved non-cytotoxic and safe. These findings suggest that yeasts with significant probiotic attributes could be recommended for various probiotic application.

The current study was designed to explore the biosynthetic potential of sevadicin in Bacillus pumilus species and its interaction with bacterial drug target molecules. The non-ribosomal peptide (NRP) cluster in B. pumilus SF-4 was preliminarily confirmed using PCR-based screening, and the bioactivity of strain SF-4 culture extract was assessed against a set of human pathogenic strains. The susceptibility assay showed that strain SF-4 extract had higher inhibitory concentrations (312-375 µg/mL) than ciprofloxacin. Genome mining of B. pumilus strains (n = 22) using AntiSMASH and BAGEL identified sevadicin coding biosynthetic gene cluster only in strain SF-4, constitutes of two core biosynthetic genes, three additional biosynthetic genes, two transport-related genes, and one regulatory gene. The molecular docking of sevadicin with various putative bacterial drug targets such as dihydropteroate, muramyl ligase E, topoisomerase, penicillin-binding protein, and in vitro safety analyses were conducted with detailed ADMET screening. The results showed that sevadicin makes hydrophobic interaction with MurE (PDB ID: 1E8C and 4C13) via hydrogen bonding, suggesting bacterial growth inhibition by disrupting the cell wall synthesis pathway and exhibiting a secure biosafety profile. The stability and compactness of sevadicin/MurE complexes were assessed via molecular dynamic simulation using RMSD, RMSF, and Rg. The simulation results revealed the binding stability of sevadicin/MurE complexes and indicated that the complexes can't be easily deformed. In conclusion, the current study explored the biosynthesis of sevadicin in B. pumilus for the first time and found that sevadicin inhibits bacterial growth by inhibiting cell wall synthesis via targeting the MurE enzyme and exhibits no toxicity.