Antimicrobial Peptides
Antimicrobial Peptides - Related Videos
10:35
Production and Testing of Antimicrobial Peptides and Their Mimics
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2026
This protocol describes a method for producing and evaluating the antimicrobial activity and cytotoxicity of the cationic peptide Mel4 and peptide mimic RK758. By integrating chemical synthesis, recombinant expression, and standardized functional assays, it provides a streamlined workflow for the production and testing of peptides and small-molecule mimics.
11:10
Expression, Purification, and Antimicrobial Activity of S100A12
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Cited by 14 •
2017
Here, we present a method to express and purify S100A12 (calgranulin C). We describe a protocol to measure its antimicrobial activity against the human pathogen H. pylori.
03:37
Assessing the Antimicrobial Activity of Nisin Variants Using an Agar Well Diffusion Assay
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2025
Source: Nickling, J. H., et.al. Antimicrobial Peptides Produced by Selective Pressure Incorporation of Non-canonical Amino Acids. J. Vis. Exp. (2018)This video demonstrates an agar well diffusion assay used to evaluate the antimicrobial activity of nisin variants. It shows how Lactococcus lactis expressing the membrane-bound peptidase NisP activates nisin precursors produced in E. coli, resulting in growth inhibition halos. The size of these halos reflects the bioactivity of each nisin variant.
10:13
Production and Visualization of Bacterial Spheroplasts and Protoplasts to Characterize Antimicrobial Peptide Localization
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Cited by 13 •
2018
Here we present a protocol to produce gram-negative Escherichia coli (E. coli) spheroplasts and gram-positive Bacillus megaterium (B. megaterium) protoplasts to clearly visualize and rapidly characterize peptide-bacteria interactions. This provides a systematic method to define membrane localizing and translocating peptides.
04:12
An In Vitro Technique to Study Antimicrobial Treatments on Bacterial Aggregates
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2025
This video demonstrates an in vitro technique to study the impact of antimicrobial treatment on Pseudomonas aeruginosa (Pa) aggregates. Fluorescently-labeled Pa cells are grown as aggregates, mimicking the growth pattern during infection. Upon challenging the aggregates with a sublethal concentration of the antibiotic colistin, the real-time assessment of the bacteria-antibiotic interaction is performed via fluorescence microscopy.
FAQs
Many antimicrobial peptides are attracted to negatively charged microbial membranes through electrostatic interactions. This initial association concentrates the molecules at the membrane surface, where their sequence, charge, and structure influence subsequent behavior. Depending on these properties, peptides may disrupt membrane organization, form pores, or penetrate the cell, making membrane recognition an important early step in antimicrobial activity.
Membrane-associated peptides can produce several outcomes rather than one universal response. Some disrupt the membrane directly, while others form pores or cross the membrane to affect intracellular targets. This distinction matters because antimicrobial activity may result from physical damage to the cell boundary, interference inside the microbe, or a combination of both mechanisms.
Activity depends on interconnected features of the peptide and its surroundings. Sequence influences the molecule's composition, while charge and structural organization affect how it interacts with microbial membranes. Environmental conditions can further modify these interactions. Consequently, the same peptide may not behave identically under every condition, and interpreting activity requires considering molecular and environmental factors together.
Natural peptides provide models for understanding biological defense, whereas synthetic molecules allow researchers to investigate how particular sequence, charge, or structural features relate to activity. Both can be examined through their effects on microbial membranes and intracellular targets. Comparing them helps connect molecular design with antimicrobial behavior and may inform research on alternative anti-infective strategies.
They reveal how organisms can respond to infectious microbes as part of innate immunity, the biological defense system that does not depend on the highly specific recognition associated with adaptive responses. Examining these molecules also clarifies host-microbe interactions across diverse organisms. Their activity links molecular membrane effects with broader questions about protection and infection biology.
Their relevance comes from mechanisms that can involve membrane disruption, pore formation, or intracellular effects rather than relying only on conventional antimicrobial targets. This makes them candidates for research into alternative anti-infective therapies. Studies also examine how sequence, charge, structure, and environmental conditions influence activity, with the goal of understanding whether peptide-based approaches can address resistant bacterial infections.
Antimicrobial peptides are being studied in several biological and technological contexts. Their selective activity supports research into anti-infective therapies, while their interactions with microbes can inform biomaterial design. They also provide experimental systems for investigating host-microbe relationships and biological defense. These applications connect peptide chemistry and membrane activity with broader biomedical and materials research.