enterohemorrhagic e coli ehec o157 h7  (ATCC)

Journal: Nature

Article Title: Enteropathogenic bacteria evade ROCK-driven epithelial cell extrusion

doi: 10.1038/s41586-025-09645-0

Figure Lengend Snippet: a – c , Immunoblots of Caco-2 cells infected by E. coli strain EDL933. Infection with WT or NleL deficient strains ( a ). Where indicated, cells were cultured in 1 µM bortezomib (Btz) ( b ) or 10 µg ml −1 TRAIL ( c ). hpi, hours post-infection. Results are representative of three independent experiments. MOI, multiplicity of infection; p, phosphorylated; c, cleaved. d , Scheme for quantifying the cellular extrusion of dead PI + IECs from monolayers. e – g , m , Nearest neighbour internuclear distances in IEC monolayers. e , Cells from WT IEC organoids were treated for 30 min with FlaTox and DMSO vehicle, 2.5 mM cytochalasin D (CytoD) or 10 µM Y-27632. n = 8 monolayers per group. f , Cells from Rock1- and Rock2- knockout IEC organoids were stimulated with FlaTox. n = 4 monolayers per group. g , m , Cells from WT ( g ) or Villin.CreERT2 control and Rock1- and Rock2- knockout ( m ) IEC organoids were infected with Citrobacter strain DBS100 (WT, Δ nleL or +NleL). n = 4 monolayers per group. P values determined by two-tailed Mann–Whitney test. NS, not significant. Results are representative of three independent experiments. h , Quantification of extrusion time of individual cells in live-imaged WT IEC monolayers infected with Citrobacter strain DBS100 (Δ nleL or +NleL). P values determined by two-tailed Mann–Whitney test. Results are representative of two independent experiments. i – k , Colony-forming units (CFUs) in the mouse colon ( i ), colon lumen ( j ) and spleen ( k ) six days after infection with Citrobacter strain DBS100. Circles, different mice (data pooled from two experiments, n = 10 mice per group); lines, mean. P values determined by two-way ANOVA. LOD, limit of detection. l , Immunoblots of colon IECs from mice infected by Citrobacter strain DBS100. Results are representative of three independent experiments. n , Representative confocal z -stacks of the IEC cultures in m . Scale bar, 30 μm. For gel source data, see Supplementary Fig. .

Article Snippet: EHEC O157:H7 EDL933 (ATCC700927) and C. rodentium DBS100 (ATCC51459) were obtained from the American Type Culture Collection (ATCC).

Techniques: Western Blot, Infection, Cell Culture, Knock-Out, Control, Two Tailed Test, MANN-WHITNEY

Journal: Microorganisms

Article Title: Ribosomal Hibernation Factor Links Quorum-Sensing to Acid Resistance in EHEC

doi: 10.3390/microorganisms13081730

Figure Lengend Snippet: Quorum sensing-dependent enhancement of acid resistance in EHEC. ( A ) Exogenous AHL augments acid survival. Stationary-phase wild-type EDL933 was subjected to pH 2.5 with 0, 10, or 100 μM 3-oxo-C6-AHL for 1–3 h. Survival rates (relative CFU = CFUh/CFU0) were quantified through colony enumeration (n = 3 biological replicates; mean ± SEM; * p < 0.05, ** p < 0.01, *** p < 0.001 versus 0 μM at corresponding time points). ( B ) Endogenous AHL production confirmed by cross-streaking. WT/ pyenI (left plate) activated violacein biosynthesis in CV026, verifying functional signal synthesis. Controls: C6-HSL-positive control, EDL933 WT-negative control. ( C ) Endogenous AHL signaling promotes acid tolerance. Survival kinetics of WT versus yenI -expressing strain (WT/ pyenI ) under pH 2.5 exposure. Relative CFU data demonstrate significant protection by yenI -derived AHL ( p < 0.01 versus WT at matched durations).

Article Snippet: The enterohemorrhagic Escherichia coli (EHEC) O157:H7 strain EDL933 (ATCC 43895) [ ] and its isogenic mutants were preserved at −80 °C in Lysogeny Broth (LB; BD DifcoTM, Franklin Lakes, NJ, USA) supplemented with 20% ( v / v ) glycerol.

Techniques: Functional Assay, Positive Control, Negative Control, Expressing, Derivative Assay

Journal: Microorganisms

Article Title: Ribosomal Hibernation Factor Links Quorum-Sensing to Acid Resistance in EHEC

doi: 10.3390/microorganisms13081730

Figure Lengend Snippet: Transcriptomic profiling and functional validation of acid stress response in EHEC. ( A ) Differential expression analysis. Volcano plot identifies significantly altered transcripts between AHL-treated and untreated groups. X -axis: log 2 fold-change; Y -axis: −log 10 (adjusted p -value). Red points: up-regulated genes (log 2 FC > 1, FDR < 0.01); green points: down-regulated genes (log 2 FC < −1, FDR < 0.01); blue points: non-significant genes. ( B ) Gene ontology enrichment. Terms are categorized by biological process (red bars), cellular component (green bars), and molecular function (blue bars). Ribosomal pathways show peak enrichment (−log 10 [padj] = 12.1 for cellular components). ( C ) KEGG pathway analysis. Significantly enriched pathways include ribosome assembly (boxed in red; −log 10 [padj] = 10.5) and pathogenic E. coli infection. ( D ) Technical validation of RNA-seq data. Log 2 fold-change comparison between sequencing and RT-qPCR results for selected ribosomal genes ( rmf , raiA , rpsL , rplM …). Error bars: ±SD. ( E ) Acid resistance impairment in rmf mutant. Wild-type (WT), Δ rmf deletion mutant, and genetically complemented strain (Δ rmf / prmf ) were challenged at pH 2.5 for 1–3 h. Survival rates (relative CFU = CFU h /CFU 0 ; mean ± SEM; n = 3) reveal significant attenuation in Δ rmf ( ** p < 0.01, *** p < 0.001 versus WT at corresponding time points).

Article Snippet: The enterohemorrhagic Escherichia coli (EHEC) O157:H7 strain EDL933 (ATCC 43895) [ ] and its isogenic mutants were preserved at −80 °C in Lysogeny Broth (LB; BD DifcoTM, Franklin Lakes, NJ, USA) supplemented with 20% ( v / v ) glycerol.

Techniques: Functional Assay, Biomarker Discovery, Quantitative Proteomics, Infection, RNA Sequencing, Comparison, Sequencing, Quantitative RT-PCR, Mutagenesis

Journal: Microorganisms

Article Title: Ribosomal Hibernation Factor Links Quorum-Sensing to Acid Resistance in EHEC

doi: 10.3390/microorganisms13081730

Figure Lengend Snippet: RMF modulates acid-adaptive gene expression and stress survival in EHEC. ( A ) gad system dysregulation in Δ rmf under lethal acidity. After 2 h at pH 2.5, gad A, gad C, gad W, and gad E expression decreased in Δ rmf versus WT (* p < 0.05, ** p < 0.01, *** p < 0.001, **** p < 0.0001). Genetic complementation (Δ rmf / prmf ) restored baseline levels. ( B ) Impaired chaperone induction in Δ rmf . Under identical conditions, hdeA , hdeB , and adiA were downregulated (* p < 0.05, ** p < 0.01, *** p < 0.001, **** p < 0.0001). Error bars: ±SD. ( C ) Growth curves. Growth curves show comparable kinetics among WT, Δ rmf , and Δ rmf / prmf . ( D ) Catastrophic acid sensitivity in Δ rmf . ( E ) Δ rmf starvation vulnerability. In PBS, Δ rmf viability dropped versus WT.

Article Snippet: The enterohemorrhagic Escherichia coli (EHEC) O157:H7 strain EDL933 (ATCC 43895) [ ] and its isogenic mutants were preserved at −80 °C in Lysogeny Broth (LB; BD DifcoTM, Franklin Lakes, NJ, USA) supplemented with 20% ( v / v ) glycerol.

Techniques: Gene Expression, Expressing

Journal: Microorganisms

Article Title: Ribosomal Hibernation Factor Links Quorum-Sensing to Acid Resistance in EHEC

doi: 10.3390/microorganisms13081730

Figure Lengend Snippet: RMF is indispensable for AHL-enhanced acid survival in EHEC. ( A ) Exogenous AHL fails to rescue acid sensitivity in Δ rmf . The Δ rmf mutant exposed to pH 2.5 for 1–3 h showed minimal protection from 3-oxo-C6-AHL. Data: Relative CFU = CFU h /CFU 0 (mean ± SEM; * p < 0.05, ** p < 0.01, *** p < 0.001 vs. 0 μM at matched time points). ( B ) Endogenous AHL partially restores acid resistance. Complementation with yenI (Δ rmf / pyenI ) provided ≤3.9-fold protection after 3 h at pH 2.5 versus 7.0-fold in WT/ pyenI (* p < 0.05 vs. Δ rmf) . ( C ) Plate assay demonstrating exogenous AHL efficacy gap. WT maintained confluent growth at 10 6 dilution after 3 h acid stress with 100 μM AHL, while Δ rmf required 1000× higher cell concentrations for detection. ( D ) Endogenous AHL production enhances acid survival. WT/ pyenI and Δ rmf / pyenI exhibited denser colonization versus non-AHL-producing counterparts at standardized dilutions (10 4 –10 6 ) after 3 h exposure.

Article Snippet: The enterohemorrhagic Escherichia coli (EHEC) O157:H7 strain EDL933 (ATCC 43895) [ ] and its isogenic mutants were preserved at −80 °C in Lysogeny Broth (LB; BD DifcoTM, Franklin Lakes, NJ, USA) supplemented with 20% ( v / v ) glycerol.

Techniques: Mutagenesis