New and old tools to evaluate new antimicrobial peptides

Rudilla, Héctor; Merlos, Alexandra; Sans-Serramitjana, Eulàlia; Fusté, Ester; Sierra, Josep M.; Zalacain, Antonio; Vinuesa, Teresa; Viñas, Miguel

doi:10.3934/microbiol.2018.3.522

Cited by 22 publications

(15 citation statements)

References 58 publications

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“…This result may be due to the different metabolism of the microorganism in each of its growth phases. In the lag phase the microorganism adapts to a new environment, synthesizes new components, there is no cell replication, and prepares for cell division [32], while in the exponential phase it grows at a high rate under optimal conditions of temperature, availability of nutrient and oxygen [33]. Another factor associated with Ib-M activity in the two growth phases would be the quantitative relationship between the concentration of the peptide and the number of bacteria; since the concentration of the inoculum in the lag phase was 5x10 5 CFU / mL while in the log phase it was 1x10 8 CFU / mL.…”

Section: Discussionmentioning

confidence: 99%

Antimicrobial activity of Ib-M peptides against Escherichia coli O157: H7

Prada-Prada¹,

Flórez-Castillo

Farfán-García³

et al. 2020

PLoS ONE

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The development of new antimicrobial peptides has become an attractive alternative to conventional antibiotics due to the increasing rates of microbial drug resistance. Ib-M corresponds to a family of cationic synthetic peptides, 20 amino acids in length, that have shown inhibitory effect against the non-pathogenic strain Escherichia coli K-12. This work evaluated the antimicrobial potential of Ib-M peptides against the pathogenic E. coli O157: H7 using a reference strain and a clinical isolate. The Ib-M peptides showed antibacterial activity against both strains of E. coli O157: H7; the minimum inhibitory concentration of Ib-M peptides ranged from 1.6 to 12.5 μM and the minimum bactericidal concentration ranged from 3.7 to 22.9 μM, being Ib-M1 and Ib-M2 the peptides that presented the highest inhibitory effect. Time-kill kinetics assay showed a reduction of the bacterial population by more than 95% after 4 hours of exposure to 1xMIC of Ib-M1. Low cytotoxicity was observed in VERO cells with 50% cytotoxic concentration in the range from 197.5 to more than 400 μM. All peptides showed a random structure in hydrophilic environments, except Ib-M1, and all of them transitioned to an α-helical structure when the hydrophobicity of the medium was increased. In conclusion, these findings support the in vitro antimicrobial effect of Ib-M peptides against the pathogenic bacteria E. coli O157: H7 and prove to be promising molecules for the development of new therapeutic alternatives.

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Section: Discussionmentioning

confidence: 99%

Antimicrobial activity of Ib-M peptides against Escherichia coli O157: H7

Prada-Prada¹,

Flórez-Castillo

Farfán-García³

et al. 2020

PLoS ONE

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“…Broad-spectrum AMPs have thus been suggested as an alternative to conventional antibiotics for combatting bacterial infections, as AMPs have rapid killing kinetics, low levels of induced resistance and low host toxicity [68,77,78,79,80]. Time-kill studies [81] for evaluating sarconesin II antimicrobial activity against E. coli (Figure 2a) demonstrated that the peptide totally killed the bacterium after 240 min, thereby confirming its bactericidal activity.…”

Section: Discussionmentioning

confidence: 94%

Sarconesin II, a New Antimicrobial Peptide Isolated from Sarconesiopsis magellanica Excretions and Secretions

et al. 2019

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Antibiotic resistance is at dangerous levels and increasing worldwide. The search for new antimicrobial drugs to counteract this problem is a priority for health institutions and organizations, both globally and in individual countries. Sarconesiopsis magellanica blowfly larval excretions and secretions (ES) are an important source for isolating antimicrobial peptides (AMPs). This study aims to identify and characterize a new S. magellanica AMP. RP-HPLC was used to fractionate ES, using C18 columns, and their antimicrobial activity was evaluated. The peptide sequence of the fraction collected at 43.7 min was determined by mass spectrometry (MS). Fluorescence and electronic microscopy were used to evaluate the mechanism of action. Toxicity was tested on HeLa cells and human erythrocytes; physicochemical properties were evaluated. The molecule in the ES was characterized as sarconesin II and it showed activity against Gram-negative (Escherichia coli MG1655, Pseudomonas aeruginosa ATCC 27853, P. aeruginosa PA14) and Gram-positive (Staphylococcus aureus ATCC 29213, Micrococcus luteus A270) bacteria. The lowest minimum inhibitory concentration obtained was 1.9 μM for M. luteus A270; the AMP had no toxicity in any cells tested here and its action in bacterial membrane and DNA was confirmed. Sarconesin II was documented as a conserved domain of the ATP synthase protein belonging to the Fli-1 superfamily. The data reported here indicated that peptides could be alternative therapeutic candidates for use in infections against Gram-negative and Gram-positive bacteria and eventually as a new resource of compounds for combating multidrug-resistant bacteria.

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“…These long response times can further introduce inconsistencies. Depending on the duration, antimicrobial depletion and bacterial regrowth can further contribute to variability 4 . Mechanistic information is also limited, as observations often only describe end effects.…”

Section: Introductionmentioning

confidence: 99%

Detection of Cell Membrane Interactions with Lipid-functionalized Single-walled Carbon Nanotubes

Kallmyer¹,

Eeg²,

Khor³

et al. 2021

Preprint

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Membrane-active molecules are of great importance to drug delivery and antimicrobials applications. While the ability to prototype new membrane-active molecules has improved greatly with the advent of automated chemistries and rapid biomolecule expression techniques, testing methods are still limited by throughput, cost, and modularity. Existing methods suffer from feasibility constraints of working with pathogenic, living cells and by intrinsic limitations of model systems. Herein, we demonstrate an abiotic sensor that uses semiconducting single-walled carbon nanotubes (SWNT) as near infrared fluorescent transducers to report membrane interactions. This sensor is comprised of SWNT aqueously suspended in a phospholipid monolayer; these SWNT probes are very sensitive to solvent access (changes in permittivity) and thus report morphological changes to the membrane by modulation of fluorescent signal where binding and disruption are reported as brightening and attenuation, respectively. This mechanism is first demonstrated with chemical and physical membrane-disruptive agents including ethanol, sodium dodecyl sulfate, and application of electrical pulses. Known cell-penetrating and antimicrobial peptides are then used to demonstrate how the dynamic response of these sensors can be deconvoluted to evaluate different, parallel mechanisms of interaction. Lastly, SWNT functionalized in several different bacterial lipopolysaccharides (P aeruginosa, K pneumoniae, and E coli) are used to evaluate a panel of known membrane-disrupting antimicrobials to demonstrate that drug selectivity can be assessed by suspension of SWNT with different membrane materials.

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New and old tools to evaluate new antimicrobial peptides

Cited by 22 publications

References 58 publications

Antimicrobial activity of Ib-M peptides against Escherichia coli O157: H7

Antimicrobial activity of Ib-M peptides against Escherichia coli O157: H7

Sarconesin II, a New Antimicrobial Peptide Isolated from Sarconesiopsis magellanica Excretions and Secretions

Detection of Cell Membrane Interactions with Lipid-functionalized Single-walled Carbon Nanotubes

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