Journal: bioRxiv

Article Title: Division-arrest induced filamentation protects uropathogenic Escherichia coli from killing by the cathelicidin antimicrobial peptide LL-37

doi: 10.64898/2026.01.29.702582

Figure Lengend Snippet: LL-37 preferentially permeabilizes actively dividing cells. E. coli BW25113 cells were grown in M9-glucose minimal medium and mid-logarithmic phase bacteria were then placed on 1% agarose pads with A-C) SYTOX™ Green nucleic acid stain or D-E) propidium iodide. Live images were collected while 3 µl of 50-100 µg/ml LL-37 in water was added to the edge of the agarose pad. Arrows indicate dead cells with evidence of a mid-cell invagination consistent with the formation of a divisome A&B; C&D. Statistical significance was tested by unpaired Student’s t-test comparing the average percentage of dead cells that contained a visible mid-cell invagination consistent with divisome formation and activation from three independent biological replicates. N = 141 to 308 dead cells per replicate measured via SYTOX Green staining and N = 77 to 232 dead cells per replicate for PI mediated killing.

Article Snippet: Total lipid concentration of the E. coli Polar Lipid Extract (PLE) (Avanti Polar Lipids) was calculated based on the reported distribution of 67% (w/w) phosphatidylethanolamine, 23.2% (w/w) phosphatidylglycerol and 9.8% (w/w) Cardiolipin on the company website.

Techniques: Bacteria, Staining, Activation Assay

Journal: bioRxiv

Article Title: Division-arrest induced filamentation protects uropathogenic Escherichia coli from killing by the cathelicidin antimicrobial peptide LL-37

doi: 10.64898/2026.01.29.702582

Figure Lengend Snippet: Induction of minicells via deletion of minCD leads to aberrant polar localization of the divisome site and induces LL-37-mediated killing from non-septal regions. A) Deletion of minCD or overexpression of FtsZ alters E. coli cell length and the distribution of cell lengths within the population. At least 1700 cells total were measured per strain and cells from three independent experiments were measured. The means of lengths measured in each experiment were compared by a log normal Brown-Forsynthe and Welch’s ANOVA with Dunnett’s T3 post-hoc testing. B) BW2511311 minCD cells show LL-37 mediated killing from polar division sites. The site of LL-37-mediated killing of E. coli K12 vs K1211 minCD bacteria were compared via two-way ANOVA with Šídák’s post-hoc test to determine whether different strains showed different sites of killing C) dying BW25113 or D) filamentous E. coli BW2511311 minC D cell upon exposure to LL-37 in the presence of propidium iodide

Article Snippet: Total lipid concentration of the E. coli Polar Lipid Extract (PLE) (Avanti Polar Lipids) was calculated based on the reported distribution of 67% (w/w) phosphatidylethanolamine, 23.2% (w/w) phosphatidylglycerol and 9.8% (w/w) Cardiolipin on the company website.

Techniques: Over Expression, Bacteria

Journal: bioRxiv

Article Title: Division-arrest induced filamentation protects uropathogenic Escherichia coli from killing by the cathelicidin antimicrobial peptide LL-37

doi: 10.64898/2026.01.29.702582

Figure Lengend Snippet: - LL-37 induces fission in A) polar E. coli lipid derived supported membrane nanotubes and B) synthetic phosphatidyl choline derived nanotubes. C and D) LL-37 causes transient bulging and thinning of lipid nanotubes concomitant with membrane fission events. E) Polar lipid and POPC-derived nanotubes are disrupted at similar rates F) the presence of polar lipids in nanotube preparations increases the range of nanotube sizes that are disrupted by exposure to LL-37. Fission rates were compared by Student’s t-test while comparisons of nanotube sizes formed to nanotube sizes that underwent fission were compared by Kruskall-Wallis ANOVA with Dunn’s Multiple Comparison post-hoc tests to compare specific groups.

Article Snippet: Total lipid concentration of the E. coli Polar Lipid Extract (PLE) (Avanti Polar Lipids) was calculated based on the reported distribution of 67% (w/w) phosphatidylethanolamine, 23.2% (w/w) phosphatidylglycerol and 9.8% (w/w) Cardiolipin on the company website.

Techniques: Derivative Assay, Membrane, Comparison