Journal: Frontiers in Microbiology

Article Title: Systematically Studying the Optimal Amino Acid Distribution Patterns of the Amphiphilic Structure by Using the Ultrashort Amphiphiles

doi: 10.3389/fmicb.2020.569118

Figure Lengend Snippet: (A) Time-kill kinetic curves of W5 (A-1) , L5 (A-2) , and melittin (A-3) at 1× MBC against E. coli ATCC 25922 and S. aureus 29213. (B) Resistance proceedings in the presence of a sub-MBC concentration of the peptides against P. aeruginosa ATCC 27853. The graph was from three independent experiments, and each independent experiment contained three technical replicates.

Article Snippet: Mid-log phase E. coli ATCC 25922 cells (OD 600 = 0.2) were incubated with NPN (10 μM) in 5 mM HEPES buffer (pH 7.4, containing 5 mM glucose) for 30 min.

Techniques: Concentration Assay

Journal: Frontiers in Microbiology

Article Title: Systematically Studying the Optimal Amino Acid Distribution Patterns of the Amphiphilic Structure by Using the Ultrashort Amphiphiles

doi: 10.3389/fmicb.2020.569118

Figure Lengend Snippet: Super-resolution microscopy image analysis of S. aureus 29213 and E. coli ATCC 25922 treated with PI, FITC-labeled W5 and FITC-labeled L5. The green signal is from the FITC peptides, and the red signal is from PI. The FITC peptides mainly cover the surface of the membrane, and PI is a nucleic acid dye that can penetrate broken cells and release red fluorescence.

Article Snippet: Mid-log phase E. coli ATCC 25922 cells (OD 600 = 0.2) were incubated with NPN (10 μM) in 5 mM HEPES buffer (pH 7.4, containing 5 mM glucose) for 30 min.

Techniques: Super-Resolution Microscopy, Labeling, Membrane, Fluorescence

Journal: Frontiers in Microbiology

Article Title: Systematically Studying the Optimal Amino Acid Distribution Patterns of the Amphiphilic Structure by Using the Ultrashort Amphiphiles

doi: 10.3389/fmicb.2020.569118

Figure Lengend Snippet: (A) Peptide binding affinity to LPS from E. coli O111:B4. The fluorescence intensity was monitored at an excitation wavelength of 580 nm and an emission wavelength of 620 nm. (B) The outer membrane permeability induced by W5, L5, and melittin. The uptake of NPN by E. coli in the presence of different concentrations of W5, L5 and melittin was determined using the fluorescent dye (NPN) assay. The NPN uptake was monitored at an excitation wavelength of 350 nm and an emission wavelength of 420 nm. (C) The cytoplasmic membrane potential variation of E. coli treated with different concentrations of W5 (C-1) , L5 (C-2) , or melittin (C-3) , as assessed by the release of the membrane potential-sensitive dye DiSC 3 -5. The fluorescence intensity was monitored at an excitation wavelength of 622 nm and an emission wavelength of 670 nm as a function of time. (D) Inner membrane permeability of the peptides. The hydrolysis of ONPG due to the release of cytoplasmic β-galactosidase by E. coli treated with different concentrations of W5 (D-1) , L5 (D-2) , or melittin (D-3) was measured spectroscopically at an absorbance of 420 nm as a function of time. The graphs were derived from the average of three independent trials.

Article Snippet: Mid-log phase E. coli ATCC 25922 cells (OD 600 = 0.2) were incubated with NPN (10 μM) in 5 mM HEPES buffer (pH 7.4, containing 5 mM glucose) for 30 min.

Techniques: Binding Assay, Fluorescence, Membrane, Permeability, NPN Assay, Derivative Assay

Journal: Frontiers in Microbiology

Article Title: Systematically Studying the Optimal Amino Acid Distribution Patterns of the Amphiphilic Structure by Using the Ultrashort Amphiphiles

doi: 10.3389/fmicb.2020.569118

Figure Lengend Snippet: SEM micrographs of E. coli ATCC 25922 and S. aureus 29213. (A) E. coli -control, (B) E. coli treated with W5 (blebbing), (C) E. coli treated with L5 (hole and wrinkle formation), (D) S. aureus control, (E) S. aureus treated with W5 (content leakage), and (F) S. aureus treated with L5 (hole formation). Scale bar = 2.00 μm (A–E) , 1.00 μm (F) .

Article Snippet: Mid-log phase E. coli ATCC 25922 cells (OD 600 = 0.2) were incubated with NPN (10 μM) in 5 mM HEPES buffer (pH 7.4, containing 5 mM glucose) for 30 min.

Techniques: Control

Journal: Frontiers in Microbiology

Article Title: Systematically Studying the Optimal Amino Acid Distribution Patterns of the Amphiphilic Structure by Using the Ultrashort Amphiphiles

doi: 10.3389/fmicb.2020.569118

Figure Lengend Snippet: TEM micrographs of E. coli ATCC 25922 and S. aureus 29213. (A) E. coli control, (B) E. coli treated with W5 (content leakage), (C) E. coli treated with L5 (obviously clear areas), (D) S. aureus control, (E) S. aureus treated with W5 (sparse cytoplasmic distribution), and (F) S. aureus treated with L5 (cytoplasmic membrane and outer membrane separation and hole formation). Scale bar = 500 nm (A,B,D–F) , 1,000 nm (C) .

Article Snippet: Mid-log phase E. coli ATCC 25922 cells (OD 600 = 0.2) were incubated with NPN (10 μM) in 5 mM HEPES buffer (pH 7.4, containing 5 mM glucose) for 30 min.

Techniques: Control, Membrane