Journal: BMC Microbiology

Article Title: Global transcriptional regulation by the CodY gene: identification of critical compounds that enhance oxidative stress resistance in Lactobacillus delbrueckii subsp. Bulgaricus

doi: 10.1186/s12866-025-04478-3

Figure Lengend Snippet: Impact of S. thermophilus codY status on L. delbrueckii subsp. bulgaricus ATCC 11842 physiology in the Transwell co-culture system. A 24-h growth curve of L. delbrueckii . Lower chamber was inoculated at 2 % (v/v) with L. delbrueckii alone; upper chamber contained either WT ST-1 (black circles) or Δ codY (red triangles) or no bacterium (open squares, C-group). Samples were taken every 2 h and enumerated on MRS agar. Δ codY co-culture reduced final cell density by ~1 log (p < 0.01, two-way ANOVA). B Viable counts at 6 h and 12 h (mean ± SD, n = 3). Letters a–c denote significant differences (p < 0.05, Tukey’s HSD). C Hydrogen-peroxide challenge. Exponential-phase L. delbrueckii from (A) were exposed to 5 mM or 10 mM H 2 O 2 for 30 min, serially diluted, spotted on MRS, and counted after 48 h anaerobic incubation at 42 °C. Survival is expressed as % of untreated control. Grey bars: WT ST-1 co-culture; red bars: Δ codY co-culture. Asterisks indicate p < 0.01 versus WT (Student’s t-test). Note: the absolute CFU ml-1 at t = 0 min differed slightly between WT and Δ codY co-cultures (6.18 ± 0.36 vs 5.26 ± 0.04 log CFU ml-1, respectively) because OD 600 normalization equalises cell density but not historical viability; all survival percentages are therefore normalised to their own t = 0 min count to isolate the effect of H 2 O 2 exposure.

Article Snippet: Fig. 3 Impact of S. thermophilus codY status on L. delbrueckii subsp. bulgaricus ATCC 11842 physiology in the Transwell co-culture system.

Techniques: Co-Culture Assay, Incubation, Control

Journal: BMC Microbiology

Article Title: Global transcriptional regulation by the CodY gene: identification of critical compounds that enhance oxidative stress resistance in Lactobacillus delbrueckii subsp. Bulgaricus

doi: 10.1186/s12866-025-04478-3

Figure Lengend Snippet: PCA and metabolite classification overview of UPLC-Q-TOF MSE datasets. Group codes A – F are defined in Table A PCA score plot (PC1 vs PC2) of intracellular metabolomes from groups A , B and C (cells of L. delbrueckii ). Ellipses represent 95 % confidence regions. PC1 (23 %) and PC2 (21.8%) clearly separate the three nutritional environments. B PCA score plot of extracellular metabolomes groups D , E , F). Separation pattern analogous to A , confirming CodY-dependent metabolic footprints. C Relative contribution of major chemical classes across all detected features (positive-ion mode, intracellular). “Organic acids & derivatives” and “Lipids & lipid-like molecules” dominate (~20 % and ~15 %, respectively). D Same as C but for extracellular fraction; similar distribution, indicating substantial metabolite release.

Article Snippet: Fig. 3 Impact of S. thermophilus codY status on L. delbrueckii subsp. bulgaricus ATCC 11842 physiology in the Transwell co-culture system.

Techniques:

Journal: BMC Microbiology

Article Title: Global transcriptional regulation by the CodY gene: identification of critical compounds that enhance oxidative stress resistance in Lactobacillus delbrueckii subsp. Bulgaricus

doi: 10.1186/s12866-025-04478-3

Figure Lengend Snippet: Differences in oxidative stress capacity after addition of oxidative stress signaling molecules to culture L. delbrueckii subsp. bulgaricus ATCC11842.

Article Snippet: Fig. 3 Impact of S. thermophilus codY status on L. delbrueckii subsp. bulgaricus ATCC 11842 physiology in the Transwell co-culture system.

Techniques: