Journal: Microorganisms

Article Title: Saccharomyces cerevisiae TAD1 Mutant Strain As Potential New Antimicrobial Agent: Studies on Its Antibacterial Activity and Mechanism of Action

doi: 10.3390/microorganisms13122848

Figure Lengend Snippet: Growth curve measurement. ( A ) Loss of TAD1 does not impair S. cerevisiae growth. Growth curves of parental strain BY4743, S. boulardii , and S. cerevisiae TAD1-KO cultivated in YPD at 30 °C, 200 rpm for 24 h. The superimposable curves indicate that TAD1 deletion is growth-neutral under standard laboratory conditions. ( B – D ) S. cerevisiae TAD1-KO elicits potent metabolite-mediated growth suppression. Growth curves of E. coli , S. aureus , and S. typhi exposed to 90% ( v / v ) S. cerevisiae TAD1-KO , BY4743, or nutrient controls at 37 °C, 200 rpm. S. cerevisiae TAD1-KO CFS significantly delayed lag-to-log transition, reduced µmax, and lowered stationary-phase density. Equivalent growth in sterile water and YPD controls excludes nutrient limitation, confirming inhibition by secreted bioactive metabolites. Data are means ± SD (n = 3); ** p < 0.01; *** p < 0.001; ns denotes no statistically significant difference.

Article Snippet: Even at 25% ( v / v ), CFS reduced the CV-stainable biomass below the untreated control, while 90% CFS suppressed biofilm formation to ≤16% for all tested strains: E. coli ATCC 25922 (10.5%), E. coli mcr-1 (11.1%), S. aureus ATCC 29213 (9.0%), MRSA (10.8%), and S. typhi SL1344 (15.9%).

Techniques: Sterility, Inhibition

Journal: Microorganisms

Article Title: Saccharomyces cerevisiae TAD1 Mutant Strain As Potential New Antimicrobial Agent: Studies on Its Antibacterial Activity and Mechanism of Action

doi: 10.3390/microorganisms13122848

Figure Lengend Snippet: S. cerevisiae TAD1-KO CFS inhibits biofilm formation and downregulates biofilm-associated genes: ( A ) Quantitative CV assay showing dose-dependent suppression of biofilms in E. coli ATCC25922, E. coli ( mcr-1 ), S. aureus ATCC29213, MRSA, and S. typhi SL1344 after 24 h exposure to 25–90% ( v / v ) S. cerevisiae TAD1-KO CFS. ( B ) 96-well plate images confirming progressive biofilm disruption with increasing CFS concentration. ( C ) Light-microscopy images confirming progressive biofilm disruption with increasing CFS concentration. ( D ) qRT-PCR demonstrating significant downregulation of key biofilm genes ( fimH , fliC , csgA , csgD ) in E. coli treated with 50% S. cerevisiae TAD1-KO CFS versus untreated control. Data are means ± SD (n = 3); * p < 0.05; ** p < 0.01; *** p < 0.001.

Article Snippet: Even at 25% ( v / v ), CFS reduced the CV-stainable biomass below the untreated control, while 90% CFS suppressed biofilm formation to ≤16% for all tested strains: E. coli ATCC 25922 (10.5%), E. coli mcr-1 (11.1%), S. aureus ATCC 29213 (9.0%), MRSA (10.8%), and S. typhi SL1344 (15.9%).

Techniques: Disruption, Concentration Assay, Light Microscopy, Quantitative RT-PCR, Control

Journal: Microorganisms

Article Title: Saccharomyces cerevisiae TAD1 Mutant Strain As Potential New Antimicrobial Agent: Studies on Its Antibacterial Activity and Mechanism of Action

doi: 10.3390/microorganisms13122848

Figure Lengend Snippet: S. cerevisiae TAD1-KO CFS impairs adhesion, hydrophobicity, and EPS production: ( A ) Adhesion to glass after 24 h, ( B ) cell-surface hydrophobicity, and ( C ) EPS yield of E. coli , S. aureus , and S. typhi following 24 h exposure to 50% ( v / v ) S. cerevisiae TAD1-KO CFS. All parameters were significantly reduced versus untreated controls, confirming that CFS targets the early physical determinants of biofilm formation. Data are means ± SD (n = 3); * p < 0.05; ** p < 0.01; *** p < 0.001.

Article Snippet: Even at 25% ( v / v ), CFS reduced the CV-stainable biomass below the untreated control, while 90% CFS suppressed biofilm formation to ≤16% for all tested strains: E. coli ATCC 25922 (10.5%), E. coli mcr-1 (11.1%), S. aureus ATCC 29213 (9.0%), MRSA (10.8%), and S. typhi SL1344 (15.9%).

Techniques: Cell Surface Hydrophobicity

Journal: Microorganisms

Article Title: Saccharomyces cerevisiae TAD1 Mutant Strain As Potential New Antimicrobial Agent: Studies on Its Antibacterial Activity and Mechanism of Action

doi: 10.3390/microorganisms13122848

Figure Lengend Snippet: Time–kill kinetics and ultrastructural damage induced by S. cerevisiae TAD1-KO CFS. ( A ) Viable counts of E. coli exposed to 90% S. cerevisiae TAD1-KO CFS, 90% BY4743 CFS, or LB at 37 °C; bactericidal effect could be achieved within 4 h, with maximum bactericidal activity at 8 h. ( B ) Representative TEM micrographs after 6 h treatment with 50% S. cerevisiae TAD1-KO CFS: E. coli and S. aureus exhibit swelling, membrane rupture, cytoplasmic leakage, and plasmolysis compared with intact untreated cells, confirming metabolite-mediated envelope disruption. The black scale in the image represents 2 µm and 500 nm. Data are means ± SD (n = 3); *** p < 0.001.

Article Snippet: Even at 25% ( v / v ), CFS reduced the CV-stainable biomass below the untreated control, while 90% CFS suppressed biofilm formation to ≤16% for all tested strains: E. coli ATCC 25922 (10.5%), E. coli mcr-1 (11.1%), S. aureus ATCC 29213 (9.0%), MRSA (10.8%), and S. typhi SL1344 (15.9%).

Techniques: Activity Assay, Membrane, Disruption

Journal: Microorganisms

Article Title: Saccharomyces cerevisiae TAD1 Mutant Strain As Potential New Antimicrobial Agent: Studies on Its Antibacterial Activity and Mechanism of Action

doi: 10.3390/microorganisms13122848

Figure Lengend Snippet: S. cerevisiae TAD1-KO CFS sequentially disrupts envelope integrity and elicits intracellular ROS. ( A ) Time-dependent leakage of periplasmic AKP (OD 520 ) after 50% S. cerevisiae TAD1-KO CFS exposure; significant increase from 4 h onward. ( B ) NPN fluorescence assay: 50% S. cerevisiae TAD1-KO CFS raises outer-membrane permeability to the level of 1 mg mL −1 EDTA-2Na (positive control). ( C ) ONPG hydrolysis (OD 415 ), indicating inner-membrane permeabilization; slightly higher but statistically different from control (* p < 0.05). ( D ) DCFH-DA fluorescence: 90% S. cerevisiae TAD1-KO CFS triggers robust intracellular ROS accumulation (*** p < 0.001), contributing to rapid bacterial killing. ( E , F ) ROS scavengers do not impair S. cerevisiae TAD1-KO CFS bactericidal efficacy. E. coli (1 × 10 7 CFU mL −1 ) were cultured with 90% S. cerevisiae TAD1-KO CFS alone or supplemented with 1 mmol L −1 or 2 mmol L −1 VC, thiourea, or both. Viable counts (CFU mL −1 ) were determined at 0, 4 and 8 h (37 °C, 200 rpm). No statistically significant difference between groups ( p > 0.05) indicates that ROS contributes minimally to CFS-mediated killing; the lethal effect is primarily attributable to direct envelope disruption. Data are means ± SD (n = 3); * p < 0.05; ** p < 0.01; *** p < 0.001; ns denotes no statistically significant difference.

Article Snippet: Even at 25% ( v / v ), CFS reduced the CV-stainable biomass below the untreated control, while 90% CFS suppressed biofilm formation to ≤16% for all tested strains: E. coli ATCC 25922 (10.5%), E. coli mcr-1 (11.1%), S. aureus ATCC 29213 (9.0%), MRSA (10.8%), and S. typhi SL1344 (15.9%).

Techniques: Fluorescence, Membrane, Permeability, Positive Control, Control, Cell Culture, Disruption

Journal: Microorganisms

Article Title: Saccharomyces cerevisiae TAD1 Mutant Strain As Potential New Antimicrobial Agent: Studies on Its Antibacterial Activity and Mechanism of Action

doi: 10.3390/microorganisms13122848

Figure Lengend Snippet: S. cerevisiae TAD1-KO tolerates simulated gastrointestinal stress and displays superior aggregation traits. ( A ) Survival after 3 h in simulated gastric fluid (pH 3.0, pepsin 3 mg mL −1 ); S. cerevisiae TAD1-KO retained 86.0% viability. ( B ) Survival after 4 h in intestinal fluid (pH 8.0, trypsin 1 mg mL −1 , 0.3% bile); 80.7% cells remained viable. ( C ) Auto-aggregation at 5 h; S. cerevisiae TAD1-KO exceeded BY4743 by 23%. ( D ) Co-aggregation increments with E. coli , S. aureus , and S. typhi (28%, 17%, and 30% higher than BY4743, respectively). Data are means ± SD (n = 3); ** p < 0.01; *** p < 0.001; ns denotes no statistically significant difference.

Article Snippet: Even at 25% ( v / v ), CFS reduced the CV-stainable biomass below the untreated control, while 90% CFS suppressed biofilm formation to ≤16% for all tested strains: E. coli ATCC 25922 (10.5%), E. coli mcr-1 (11.1%), S. aureus ATCC 29213 (9.0%), MRSA (10.8%), and S. typhi SL1344 (15.9%).

Techniques:

Journal: Microorganisms

Article Title: Saccharomyces cerevisiae TAD1 Mutant Strain As Potential New Antimicrobial Agent: Studies on Its Antibacterial Activity and Mechanism of Action

doi: 10.3390/microorganisms13122848

Figure Lengend Snippet: G. mellonella toxicity and therapeutic efficacy of S. cerevisiae TAD1-KO . ( A ) Survival curves after a single injection of live yeast, heat-killed yeast, or CFS (n = 5 per group); no larval mortality within 5 days confirms low toxicity. ( B , C ) Models of infection with E. coli and S. aureus : live S. cerevisiae TAD1-KO and its CFS significantly extended survival (*** p < 0.001 vs. PBS), whereas heat-inactivated yeast had no effect, demonstrating that protection requires metabolically active cells. ( D ) Survival rates of G. mellonella in each group on the first day of the E. coli infection model and the S. aureus infection model. ( E , F ) On the fifth day post-infection, homogenize G. mellonella and calculate the bacterial load within each group. ( G ) After homogenization, each group was spread onto LB agar plates for counting. ** p < 0.01; *** p < 0.001; ns denotes no statistically significant difference.

Article Snippet: Even at 25% ( v / v ), CFS reduced the CV-stainable biomass below the untreated control, while 90% CFS suppressed biofilm formation to ≤16% for all tested strains: E. coli ATCC 25922 (10.5%), E. coli mcr-1 (11.1%), S. aureus ATCC 29213 (9.0%), MRSA (10.8%), and S. typhi SL1344 (15.9%).

Techniques: Drug discovery, Injection, Infection, Metabolic Labelling, Homogenization

Journal: Microorganisms

Article Title: Saccharomyces cerevisiae TAD1 Mutant Strain As Potential New Antimicrobial Agent: Studies on Its Antibacterial Activity and Mechanism of Action

doi: 10.3390/microorganisms13122848

Figure Lengend Snippet: ( A – C ) Direct co-culture reveals enhanced pathogen suppression by live S. cerevisiae TAD1-KO . Viable counts (CFU mL −1 ) of E. coli , S. aureus , and S. typhi after 16 h contact with live S. cerevisiae TAD1-KO or BY4743 at 37 °C, 200 rpm. Inhibition rates: 89.5%, 55.1%, and 52.2% for S. cerevisiae TAD1-KO versus ≤ 20% for BY4743, confirming the contribution of TAD1 deletion to antimicrobial competence. Data are means ± SD; * p < 0.05; ** p < 0.01; *** p < 0.001; ns denotes no statistically significant difference.

Article Snippet: Even at 25% ( v / v ), CFS reduced the CV-stainable biomass below the untreated control, while 90% CFS suppressed biofilm formation to ≤16% for all tested strains: E. coli ATCC 25922 (10.5%), E. coli mcr-1 (11.1%), S. aureus ATCC 29213 (9.0%), MRSA (10.8%), and S. typhi SL1344 (15.9%).

Techniques: Co-Culture Assay, Inhibition

Journal: Microorganisms

Article Title: Saccharomyces cerevisiae TAD1 Mutant Strain As Potential New Antimicrobial Agent: Studies on Its Antibacterial Activity and Mechanism of Action

doi: 10.3390/microorganisms13122848

Figure Lengend Snippet: Transwell assay confirms metabolite-mediated antibacterial activity of S. cerevisiae TAD1-KO . ( A , B ) Viable counts of E. coli and S. aureus after 16 h at 37 °C. Inhibition rates: mixed culture 81.7%, separated culture 83.7%; no significant difference between regimes ( p > 0.05, n = 3), demonstrating that diffusible metabolites, not direct contact, drive antibacterial activity. Data are means ± SD; ** p < 0.01; *** p < 0.001; ns denotes no statistically significant difference.

Article Snippet: Even at 25% ( v / v ), CFS reduced the CV-stainable biomass below the untreated control, while 90% CFS suppressed biofilm formation to ≤16% for all tested strains: E. coli ATCC 25922 (10.5%), E. coli mcr-1 (11.1%), S. aureus ATCC 29213 (9.0%), MRSA (10.8%), and S. typhi SL1344 (15.9%).

Techniques: Transwell Assay, Activity Assay, Inhibition

Journal: Microorganisms

Article Title: Saccharomyces cerevisiae TAD1 Mutant Strain As Potential New Antimicrobial Agent: Studies on Its Antibacterial Activity and Mechanism of Action

doi: 10.3390/microorganisms13122848

Figure Lengend Snippet: Antimicrobial activity of S. cerevisiae TAD1-KO is pH-dependent. Inhibitory efficacy against E. coli and S. aureus (OD 600 , 24 h) declined sharply as the native CFS (pH 4.0 ± 0.37) was stepwise neutralized to pH 7.0, demonstrating that the bactericidal effect is mediated predominantly by acidic metabolites identified in the metabolomic analysis. Data are means ± SD; *** p < 0.001; ns denotes no statistically significant difference.

Article Snippet: Even at 25% ( v / v ), CFS reduced the CV-stainable biomass below the untreated control, while 90% CFS suppressed biofilm formation to ≤16% for all tested strains: E. coli ATCC 25922 (10.5%), E. coli mcr-1 (11.1%), S. aureus ATCC 29213 (9.0%), MRSA (10.8%), and S. typhi SL1344 (15.9%).

Techniques: Activity Assay

Journal: Microorganisms

Article Title: Saccharomyces cerevisiae TAD1 Mutant Strain As Potential New Antimicrobial Agent: Studies on Its Antibacterial Activity and Mechanism of Action

doi: 10.3390/microorganisms13122848

Figure Lengend Snippet: Mechanism diagram of S. cerevisiae TAD1-KO against E. coli . S. cerevisiae TAD1-KO CFS secretes large quantities of organic acids, causing a reduction in the expression of biofilm-associated genes in E. coli (blue arrow); CFS disrupts the normal cellular structure of E. coli , leading to increased leakage of AKP (blue arrow) and NPN (pink arrow) into the extracellular space, alongside elevated intracellular ONP levels (yellow arrow). Concurrently, organic acids promote intracellular ROS accumulation (red arrow), inducing oxidative stress damage within the cell.

Article Snippet: Even at 25% ( v / v ), CFS reduced the CV-stainable biomass below the untreated control, while 90% CFS suppressed biofilm formation to ≤16% for all tested strains: E. coli ATCC 25922 (10.5%), E. coli mcr-1 (11.1%), S. aureus ATCC 29213 (9.0%), MRSA (10.8%), and S. typhi SL1344 (15.9%).

Techniques: Expressing