Probiotics and Antimicrobial Proteins最新文献

The progressive implementation of worldwide restrictions on antibiotic use has necessitated the development of sustainable alternatives for controlling bacterial diarrhea in piglets. This study investigated the effects of a cell-free supernatant (CFS) from Limosilactobacillus reuteri SBC5-3 on growth performance, intestinal inflammation, and microbiota in weaned piglets challenged with enterotoxigenic Escherichia coli K88 (ETEC K88). Forty-eight piglets were randomly assigned to four groups: a control group (CON, basal diet + physiological saline), an ETEC-challenged group (ETEC K88, basal diet + ETEC K88), a prevention group (CFS + ETEC K88, basal diet with CFS supplementation + ETEC K88), and a CFS group (CFS, basal diet with CFS supplementation + physiological saline). The CFS was administered orally at 5 mL/kg body weight for 7 days prior to challenge. Results showed that CFS pretreatment significantly reduced diarrhea rate and fecal scores, improved average daily gain, and alleviated ETEC K88-induced villus damage and lymphocyte infiltration in the jejunum and ileum. Moreover, CFS downregulated the expression of intestinal mucosal pro-inflammatory cytokines (IL1B, IL6, TNFA) and suppressed the activation of the NF-κB pathway by reducing phosphorylation of TAK1, IκBα, and p65. Intestinal microbiota analysis revealed that CFS increased the abundance of Lactobacillus and reduced Escherichia-Shigella. These findings demonstrate that L. reuteri SBC5-3 CFS effectively mitigates ETEC K88-induced diarrhea and intestinal inflammation by inhibiting NF-κB signaling and modulating intestinal microbiota, highlighting its potential as an antibiotic alternative in piglet production.

The global rise in resistance to chemical fungicides and their strict regulation by the EU, has created an urgent need for alternative antifungal strategies in agriculture. Plant defensins represent promising alternatives owing to their broad-spectrum antifungal activity, structural stability, and low toxicity to mammalian cells and plants. In this study, we identified and characterized a novel antifungal defensin, K4CBP6, from Solanum lycopersicum L., along with its γ-core peptide derivatives, K4CBP6γ1 and K4CBP6γ2, as potential biofungicide agents. Protein database mining revealed a widespread distribution of K4CBP6 homologs within the Solanaceae family. Recombinant K4CBP6 (rK4CBP6) was successfully produced using a Komagataella phaffii-based expression system, while K4CBP6γ1 and K4CBP6γ2 were chemically synthesized. Structural analyses via electrospray ionization mass spectrometry and electronic circular dichroism spectroscopy confirmed a cysteine-stabilized α-helix β-strand folded structure for rK4CBP6. In vitro susceptibility assays demonstrated that both rK4CBP6 and K4CBP6γ2 exhibited antifungal activity against major tomato pathogens, Botrytis cinerea, Cladosporium herbarum, and Fusarium oxysporum with minimum inhibitory concentrations ranging from 12.5 to 25 µg ml^-1. Furthermore, neither rK4CBP6 nor K4CBP6γ2 exhibited cytotoxic effects on mammalian cell lines or adverse effects in animal and plant model systems even at concentrations of 200 and 400 µg ml^-1. Proof-of-concept experiments on tomato plants and fruits confirmed their protective efficacy against B. cinerea and C. herbarum. These findings highlight the potential of rK4CBP6 and K4CBP6γ2 as sustainable biofungicide candidates for plant disease management, owing to their antifungal efficacy both in vitro and in planta, along with their lack of cytotoxic effects.

The Pacific white shrimp (Litopenaeus vannamei) aquaculture faces emerging threats from novel pathogens and escalating antibiotic resistance. This study successfully isolated and identified the pathogenic bacterium Acinetobacter ursingii strain 31C2 from diseased L. vannamei using an integrated approach combining microbiological, biochemical, and molecular techniques. The pathogenicity of this strain was confirmed in L. vannamei and marine medaka (Oryzias melastigma) infection models, exhibiting a strong dose-dependent mortality, with median lethal doses (LD₅₀) of 2.83 × 10⁴ CFU/g shrimp and 2.58 × 10⁶ CFU/fish, respectively. Infection caused severe hepatopancreatic necrosis (tubular deformation and epithelial vacuolation) and intestinal villi destruction. Antimicrobial susceptibility testing revealed that the 31C2 strain was resistant to tetracycline and azithromycin. To identify effective agents targeting this strain, the antimicrobial peptide Scymicrosin_7-26 (derived from Scylla paramamosain) was evaluated. The peptide had potent antibacterial activity against A. ursingii 31C2 in vitro (MIC: 3-6 µM). In vivo application significantly enhanced survival of L. vannamei and O. melastigma infected with 31C2 by 30% and 20%, respectively. Treatment drastically reduced bacterial loads in the hepatopancreas and intestine, restored tissue integrity, and modulated the immune response by suppressing the hyperactivation of the Toll and IMD pathways and their downstream transcription factors, dorsal and relish, while upregulating penaeidin3 and propo expression. This study identified A. ursingii as an emerging shrimp pathogen and validated Scymicrosin_7-26 as a promising antibiotic-free therapeutic for disease control in aquaculture.

Probiotics are live microorganisms that provide health benefits to the host by improving digestion, enhancing nutrient absorption, and modulating the immune system. Among them, lactic acid bacteria are known for producing vitamins and short-chain fatty acids, both essential for intestinal health. In this in silico study, we performed high-fidelity (PacBio HiFi) whole-genome sequencing and comprehensive comparative genomic analysis of five Lactobacillales strains (Enterococcus lactis, Enterococcus mundtii, Ligilactobacillus agilis, Limosilactobacillus reuteri, Limosilactobacillus vaginalis) isolated from the intestinal microbiota of chickens and pigs. The assembled genomes ranged from 1.8 to 2.8 Mb, with more than 98% completeness and less than 1.31% contamination. Taxonomic classification, presence of antimicrobial resistance genes, bacteriocin biosynthetic potential, carbohydrate-active enzyme repertoires and vitamin biosynthesis pathways, and capacity to degrade plant polysaccharides were investigated. Functional characterization identified 65 families of carbohydrate-active enzymes, with E. mundtii presenting the greatest diversity (43 families) and absolute number (100 terms) of enzymes. Metabolic reconstruction suggested functional specialization among strains, with xylooligosaccharide degradation exclusive to E. mundtii and pectin utilization limited to E. lactis. Genes related to the biosynthesis of B-complex vitamins, including riboflavin, folate, and menaquinone, showed heterogeneous and complementary distribution among strains. These findings suggest the potential for metabolic complementarity and cross-feeding, where metabolites produced by one strain serve as precursors for biosynthetic pathways in others. Collectively, these genome-resolved insights offer a data-driven framework for designing multi-strain probiotics aimed at improving intestinal health and feed efficiency in poultry and swine.

Background: Plant-based yogurts are preferred as natural and healthy alternatives. This study provides a comprehensive bibliometric analysis of soy-based yogurt. The changes by fermentation of soy yogurt, starters, and potential effects of soy yogurt on the intestines were evaluated.

Methods: A Web of Science database was used to analyze 76 "soy yogurt-isoflavone related (A)" articles (1998-2025) and 48 "soy yogurt-amino acid related (B)" (1997-2025), and 14 "soy yogurt-gut microbiota related (C)" articles (2016-2025) using the Bibliometrix Package and Biblioshiny interface in RStudio.

Results: Studies A have been published primarily in Food Bioscience, the Journal of Food Science, and The Science of Food and Agriculture. Studies on B have been published primarily in Food Chemistry, Food Research International, and the International Journal of Food Microbiology. The authors who have conducted the most research on the subject are Astheimer L.B. (for A) and Li (for B). According to abstract keywords, genistein and daidzein were studied in A, while "amino acids and free amino acids" were frequently associated with soy yogurt. "Yogurt and fermented" was listed in the motor themes, while "soy, milk, soymilk, fermentation, acid, probiotic, and bacteria" was listed in the basic themes. Daidzein, genistein, glycosidase, protein isolates, Streptococcus thermophilus, Lactobacillus acidophilus, and Lactobacillus delbrueckii were among the trending topics. "Gut microbiota" and "microbiota modulation" are participate in the most used term in C.

Conclusion: This study is among the articles that comprehensively address alternative functional protein sources in sustainability. Journal performance, keywords, thematic development and author statuses will support new research on soy yogurt.

This study evaluated the effects of low-dose electron beam irradiation (EBI) at 50, 100, and 150 Gy on the membrane characteristics, growth, and antimicrobial activity of the One Health probiotic strain Lactiplantibacillus plantarum ZPZ. Findings were compared with those of Lactobacillus acidophilus DDS®-1 to assess strain-specific responses. Results indicated a dose-dependent reduction in growth, with untreated Lpb. plantarum ZPZ cultures averaged 1.26 × 10⁷ CFU/mL, decreasing to 1.45 × 10⁶ CFU/mL at 150 Gy (P < 0.05). Antimicrobial efficacy also decreased from 0.16 in untreated samples to 0.31 in samples treated with 150 Gy (P < 0.05, OD₆₀₀). While surface hydrophobicity was initially reduced by 50 Gy treatment, it was restored by 150 Gy treatment, which correlated with an 82.7% increase in biofilm formation (r = 0.67). The obtained results show that EBI modulates the functional properties of Lpb. plantarum ZPZ and therefore indicates the possibility of its application in food safety and One Health strategies. Further studies are needed to elucidate the underlying molecular mechanisms.

Intensive poultry farming has significantly increased the incidence of lipid metabolic disorders, severely compromising the economic benefits of poultry industry. Currently, gamma-aminobutyric acid (GABA) is primarily used to mitigate adverse effects of heat stress in poultry, while the effects and mechanisms of GABA on lipid metabolism disorders remain underexplored. Lactobacillus plantarum (L. plantarum) serves as a significant source of GABA and is widely used in the livestock industry. This study therefore examines the effects of postbiotic GABA and the GABA-producing probiotic L. plantarum 1-2-3 on abdominal adipose tissue of laying hens following corticosterone-induced stress. To this end, hens subjected to corticosterone subcutaneous injections (4 mg/kg of body weight) were respectively received GABA (100 mg/kg BW) or L. plantarum 1-2-3 (1 × 10⁹ CFU/day). Results demonstrated that both GABA and L. plantarum 1-2-3 alleviated corticosterone-induced lipid metabolism disorders and reduced adipocyte size in abdominal fat. Additionally, expression analyses of genes and proteins related to lipid metabolism (PPARγ, C/EBPα, CD36, LPL, ATGL, and HSL) further showed that GABA and L. plantarum 1-2-3 inhibited excessive deposition of abdominal lipids in laying hens by suppressing adipogenesis and lipogenesis, while promoting lipolysis. Moreover, GABA and L. plantarum 1-2-3 both mitigated lipid deposition-induced inflammation and oxidative damage by normalizing macrophage infiltration and improving antioxidative enzyme activities (GSH-Px, T-SOD, CAT). These findings demonstrate the efficacy of GABA and L. plantarum 1-2-3 in alleviating lipid metabolism disorders in the abdominal adipose tissue of laying hens, suggesting their promise as nutritional supplements for counteracting stress-induced metabolic dysfunction.

The widespread use of commercial antibiotics has led to the emergence of multidrug resistance in pathogenic bacteria, posing a significant threat to human health and underscoring the urgent need for alternative antimicrobial agents. In this study, a bacteriocin-producing strain, Bacillus velezensis FS-3 (B. velezensis FS-3), was isolated from soil in Changbaishan, China. Fermentation conditions were optimized to enhance both bacteriocin activity and yield. A novel bacteriocin, PFS-3, was purified from B. velezensis FS-3 using hydrochloric acid precipitation, organic solvent extraction, and preparative reversed-phase high-performance liquid chromatography. Liquid chromatography-mass spectrometry/mass spectrometry analysis determined its molecular weight to be 929.16 Da, and amino acid sequencing of this peptide revealed eight amino acids (STYLFEGL). To date, the biological properties of PFS-3 have not been reported. We demonstrate here that PFS-3 exhibits low toxicity and remarkable stability under diverse conditions, including variations in temperature, pH, and the presence of metal ions or organic reagents. PFS-3 displayed broad-spectrum antimicrobial activity, with particularly strong activity against Gram-negative bacteria. Notably, its minimum inhibitory concentration against multidrug-resistant Escherichia coli B2 (MDR E. coli B2) was 16 μg/mL. Mechanistic investigations revealed that bacteriocin PFS-3 exerts bactericidal effects on MDR E. coli B2 by disrupting cardiolipin in the outer membrane of the cells. Furthermore, in vivo experiments demonstrated that PFS-3 significantly improved survival rates in infection models of MDR E. coli. In conclusion, PFS-3 is a newly identified bacteriocin with strong antibacterial activity, high stability, safety, and a favorable therapeutic index, highlighting its potential applications in the food industry and biopharmaceuticals for combating MDR E. coli infections.

In this study, an in silico screening approach was employed to mine potential bacteriocin clusters in genome-sequenced isolates of Lacticaseibacillus zeae UD 2202 and Lacticaseibacillus casei UD 1001. Two putative undescribed bacteriocin gene clusters (Cas1 and Cas2) closely related to genes encoding class IIa bacteriocins were identified. No bacteriocin activity was recorded when cell-free supernatants of strains UD 2202 and UD 1001 were tested against Listeria monocytogenes. Genes encoding caseicin A1 (casA1) and caseicin A2 (casA2) were heterologously expressed in Escherichia coli BL21 (DE3) using the nisin leader peptide cloned in-frame to the C-terminal of the green fluorescent gene (mgfp5). Nisin protease (NisP) was used to cleave caseicin A1 (casA1) and caseicin A2 (casA2) from GFP-Nisin leader fusion proteins. Both heterologously expressed peptides (casA1 and casA2) inhibited the growth of L. monocytogenes, suggesting that casA1 and casA2 are either silent in the wild-type strains or are not secreted in an active form. The minimum inhibitory concentration (MIC) of casA1 and casA2, determined using HPLC-purified peptides, ranged from < 0.2 µg/mL to 12.5 µg/mL when tested against Listeria ivanovii, Listeria monocytogenes, and Listeria innocua, respectively. A higher MIC value (25 µg/mL) was recorded for casA1 and casA2 when Enterococcus faecium HKLHS was used as the target. The molecular weight of heterologously expressed casA1 and casA2 is 5.1 and 5.2 kDa, respectively, as determined with tricine-SDS-PAGE. Further research is required to determine if genes within Cas1 and Cas2 render immunity to other class IIa bacteriocins.