scholarly journals Antimicrobial peptide activity in asymmetric bacterial membrane mimics

2021 ◽  
Author(s):  
Lisa Marx ◽  
Moritz P. K. Frewein ◽  
Enrico Federico Semeraro ◽  
Gerald N Rechberger ◽  
Karl Lohner ◽  
...  
Keyword(s):  
Antimicrobial Peptide ◽  
Lipid Membranes ◽  
Bacterial Membrane ◽  
Membrane Mimics

We report on the response of asymmetric lipid membranes composed of palmitoyl oleoyl phosphatidylethanolamine and palmitoyl oleoyl phosphatidylglycerol to interactions with the frog peptides L18W-PGLa and magainin 2 (MG2a), as...

scholarly journals Towards designing globular antimicrobial peptide mimics: role of polar functional groups in biomimetic ternary antimicrobial polymers

Soft Matter ◽  
2021 ◽  
Author(s):  
Garima Rani ◽  
Kenichi Kuroda ◽  
Satyavani Vemparala
Keyword(s):  
Molecular Dynamics ◽  
Antimicrobial Peptide ◽  
Bacterial Membrane ◽  
Simulation Data ◽  
Antimicrobial Polymers ◽  
Polar Groups ◽  
Methacrylate Polymers ◽  
Dynamics Simulations ◽  
Polar Functional Groups

Using atomistic molecular dynamics simulations, we study the interaction of ternary methacrylate polymers, composed of charged cationic, hydrophobic and neutral polar groups, with model bacterial membrane. Our simulation data shows...

Mechanical properties that influence antimicrobial peptide activity in lipid membranes

2016 ◽  
Vol 100 (24) ◽  
pp. 10251-10263 ◽  
Author(s):  
Nathaly Marín-Medina ◽  
Diego Alejandro Ramírez ◽  
Steve Trier ◽  
Chad Leidy
Keyword(s):  
Mechanical Properties ◽  
Antimicrobial Peptide ◽  
Lipid Membranes

scholarly journals Synergism between Magainin 2 and PGLa in Bacterial Membrane Mimics Leads to Membrane Fusion and Sponge Phase Formation

2020 ◽  
Vol 118 (3) ◽  
pp. 343a ◽  
Author(s):  
Ivo Kabelka ◽  
Michael Pachler ◽  
Sylvain Prévost ◽  
Ilse Letofsky-Papst ◽  
Karl Lohner ◽  
...  
Keyword(s):  
Membrane Fusion ◽  
Phase Formation ◽  
Bacterial Membrane ◽  
Membrane Mimics ◽  
Sponge Phase

scholarly journals Endotoxin, Capsule, and Bacterial Attachment Contribute to Neisseria meningitidis Resistance to the Human Antimicrobial Peptide LL-37

2009 ◽  
Vol 191 (12) ◽  
pp. 3861-3868 ◽  
Author(s):  
Allison Jones ◽  
Miriam Geörg ◽  
Lisa Maudsdotter ◽  
Ann-Beth Jonsson
Keyword(s):  
Antimicrobial Peptide ◽  
Neisseria Meningitidis ◽  
Pathogenic Bacteria ◽  
Wild Type Strain ◽  
Bacterial Attachment ◽  
Bacterial Membrane ◽  
Wild Type ◽  
Human Immune System ◽  
Sublethal Doses ◽  
Human Immune

ABSTRACT Pathogenic bacteria have evolved numerous mechanisms to evade the human immune system and have developed widespread resistance to traditional antibiotics. We studied the human pathogen Neisseria meningitidis and present evidence of novel mechanisms of resistance to the human antimicrobial peptide LL-37. We found that bacteria attached to host epithelial cells are resistant to 10 μM LL-37 whereas bacteria in solution or attached to plastic are killed, indicating that the cell microenvironment protects bacteria. The bacterial endotoxin lipooligosaccharide and the polysaccharide capsule contribute to LL-37 resistance, probably by preventing LL-37 from reaching the bacterial membrane, as more LL-37 reaches the bacterial membrane on both lipooligosaccharide-deficient and capsule-deficient mutants whereas both mutants are also more susceptible to LL-37 killing than the wild-type strain. N. meningitidis bacteria respond to sublethal doses of LL-37 and upregulate two of their capsule genes, siaC and siaD, which further results in upregulation of capsule biosynthesis.

Orientation of the antimicrobial peptide PGLa in lipid membranes determined from 19F-NMR dipolar couplings of 4-CF3-phenylglycine labels

2004 ◽  
Vol 168 (1) ◽  
pp. 153-163 ◽  
Author(s):  
Ralf W. Glaser ◽  
Carsten Sachse ◽  
Ulrich H.N. Dürr ◽  
Parvesh Wadhwani ◽  
Anne S. Ulrich
Keyword(s):  
Antimicrobial Peptide ◽  
Lipid Membranes ◽  
Dipolar Couplings ◽  
19F Nmr

scholarly journals Modulation of host lipid membrane elasticity and dipole potential induced by bacterial membrane vesicles

2019 ◽  
Author(s):  
Ashutosh Prince ◽  
Anuj Tiwari ◽  
Titas Mandal ◽  
Kuldeep Sharma ◽  
Nikhil Kanik ◽  
...  
Keyword(s):  
Physicochemical Properties ◽  
Lipid Membranes ◽  
Lipid Membrane ◽  
Membrane Vesicles ◽  
Bacterial Membrane ◽  
Dipole Potential ◽  
Long Distance ◽  
Biologically Relevant ◽  
Host Membrane ◽  
Distance Delivery

AbstractBacterial membrane vesicles (MVs) facilitate long-distance delivery of virulence factors crucial for pathogenicity. The entry and trafficking mechanisms of virulence factors inside host cells is recently emerging, however, if bacterial MVs modulate the physicochemical properties of the host lipid membrane remains unknown. Here we reconstitute the interaction of bacterial MV with host cell lipid membranes and quantitatively show that bacterial MV interaction increases the fluidity, dipole potential and elasticity of a biologically relevant multi-component host membrane. The presence of cylindrical lipids such as phosphatidylcholine and phosphatidylinositol and a moderate acyl chain length of C16 helps the MV interaction. While significant binding of bacterial MVs to the raft-like lipid membranes with phase separated regions of the membrane was observed, however, MVs have a preference for binding to the liquid disordered regions of the membrane. Further, the elevated levels of cholesterol tend to hinder the interaction of bacterial MVs. We further quantify the change in excess Gibbs free energy of mixing of bacterial MVs with host lipid membranes driving the modulation of host membrane parameters. The findings may have significant implications on the regulation of host machineries by pathogen through manipulation of host membrane properties.Significance StatementBacterial membrane vesicles (MVs) act as the long-distance delivery tools for virulence factor and thus, directly implicated in host-pathogen interactions and pathogenicity. While the mechanisms of virulence transfer is only recently emerging, however, the interaction of MVs the host cell membrane remains largely unexplored. Whether the MVs interaction can locally modulate the host lipid membrane physicochemical properties (such as fluidity, dipole potential and elasticity) remains unknown. Here, we quantitatively investigate the lipid specificity of E. Coli MV interaction and this results in increase in the fluidity, dipole potential and in-plane elasticity of a biologically relevant multi-component host membrane. The findings could be important for numerous cell-signaling processes as well as downstream events involving membrane-membrane fusion during process of phagosome maturation.

scholarly journals Effects of Antibacterial Peptide F1 on Bacterial Liposome Membrane Integrity

2021 ◽  
Vol 8 ◽  
Author(s):  
Qun Wang ◽  
Bo Peng ◽  
Mingyue Song ◽  
Abdullah ◽  
Jun Li ◽  
...  
Keyword(s):  
Antimicrobial Peptide ◽  
Membrane Structure ◽  
Bacterial Membrane ◽  
Phospholipid Membranes ◽  
Phospholipid Membrane ◽  
Gram Positive ◽  
Liposome Membrane ◽  
Gram Negative ◽  
Bacterial Membranes ◽  
Gram Positive Bacteria

Previous studies from our lab have shown that the antimicrobial peptide F1 obtained from the milk fermentation by Lactobacillus paracasei FX-6 derived from Tibetan kefir was different from common antimicrobial peptides; specifically, F1 simultaneously inhibited the growth of Gram-negative and Gram-positive bacteria. Here, we present follow-on work demonstrating that after the antimicrobial peptide F1 acts on either Escherichia coli ATCC 25922 (E. coli) or Staphylococcus aureus ATCC 63589 (S. aureus), their respective bacterial membranes were severely deformed. This deformation allowed leakage of potassium and magnesium ions from the bacterial membrane. The interaction between the antimicrobial peptide F1 and the bacterial membrane was further explored by artificially simulating the bacterial phospholipid membranes and then extracting them. The study results indicated that after the antimicrobial peptide F1 interacted with the bacterial membranes caused significant calcein leakage that had been simulated by different liposomes. Furthermore, transmission electron microscopy observations revealed that the phospholipid membrane structure was destroyed and the liposomes presented aggregation and precipitation. Quartz Crystal Microbalance with Dissipation (QCM-D) results showed that the antimicrobial peptide F1 significantly reduced the quality of liposome membrane and increased their viscoelasticity. Based on the study's findings, the phospholipid membrane particle size was significantly increased, indicating that the antimicrobial peptide F1 had a direct effect on the phospholipid membrane. Conclusively, the antimicrobial peptide F1 destroyed the membrane structure of both Gram-negative and Gram-positive bacteria by destroying the shared components of their respective phospholipid membranes which resulted in leakage of cell contents and subsequently cell death.

The pH-Responsive Property of Antimicrobial Peptide GH12 Enhances Its Anticaries Effects at Acidic pH

2020 ◽  
pp. 1-11
Author(s):  
Wentao Jiang ◽  
Junyuan Luo ◽  
Yufei Wang ◽  
Xiangshu Chen ◽  
Xuelian Jiang ◽  
...  
Keyword(s):  
Antimicrobial Peptide ◽  
Lipid Membranes ◽  
Lactic Acid Production ◽  
Tryptophan Fluorescence ◽  
Term Treatment ◽  
Tooth Surface ◽  
Acidic Ph ◽  
Ph Responsive ◽  
Short Term Treatment ◽  
Minimal Inhibitory Concentrations

Dental caries is closely related to the acidification of the biofilms on the tooth surface, in which cariogenic bacteria bring about a dramatic pH decrease and disrupt remineralisation equilibrium upon the fermentation of dietary sugars. Thus, approaches targeting the acidified niches with enhanced anticaries activities at acidic pH are highly desirable. In our previous study, a cationic amphipathic α-helical antimicrobial peptide GH12 (Gly-Leu-Leu-Trp-His-Leu-Leu-His-His-Leu-Leu-His-NH<sub>2</sub>) was designed with good stability, low cytotoxicity, and excellent antibacterial effects. Considering its potent antibacterial activity against the acidogenic bacteria and its histidine-rich sequence, it was speculated that GH12 might show enhanced antimicrobial effects at an acidic pH. In this study, the pH-responsive property of GH12 was determined to evaluate its potential as a smart acid-activated anticaries agent. GH12 possessed much lower minimal inhibitory concentrations and minimal bactericidal concentrations against various kinds of bacteria at pH 5.5 than at pH 7.2. Employing <i>Streptococcus mutans</i>, the principal caries pathogen, as the model system, it was found that GH12 showed much stronger bactericidal effects on both planktonic <i>S. mutans</i> and <i>S. mutans</i> embedded in the biofilm at pH 5.5. In addition, short-term treatment with GH12 showed much more effective inhibitory effects on water-insoluble exopolysaccharides synthesis and lactic acid production of the preformed <i>S. mutans</i> biofilm at pH 5.5. As for the mechanism exploration, it was found that the net positive charge of GH12 increased and the tryptophan fluorescence intensity heightened with the peak shifting towards the short wavelength at pH 5.5, which demonstrated that GH12 could be more easily attracted to the anionic microbial cell membranes and that GH12 showed stronger interactions with the lipid membranes. In conclusion, acidic pH enhanced the antibacterial and antibiofilm activities of GH12, and GH12 is a potential smart anticaries agent targeting the cariogenic acidic microenvironment.

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