Antimicrobial Diffusion Measurement
Antimicrobial Diffusion Measurement - Related Videos
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.
10:50
Qualitative and Quantitative Assays for Detection and Characterization of Protein Antimicrobials
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Cited by 11 •
2016
Here, we present protocols to rapidly screen and characterize enzymes for antimicrobial activity. The microslide diffusion assay and the dye-release assay utilize target bacterial substrates for qualitative and quantitative enzymatic activity evaluation.
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.
07:00
Measuring Diffusion Coefficients via Two-photon Fluorescence Recovery After Photobleaching
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Cited by 4 •
2010
In this article we will describe the procedure for measuring diffusion coefficients using multi-photon fluorescence recovery after photobleaching. We will begin by aligning the laser along the optical path to the sample and determining the proper experimental parameters, then continue generating and finally fitting fluorescence recovery curves.
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.
FAQs
An antimicrobial released from a disc or well moves outward through the agar, creating a concentration gradient. Microbial growth is prevented in the region where the compound remains sufficiently effective. The visible boundary between inhibited and growing microorganisms therefore reflects the area reached by effective antimicrobial concentrations under the assay conditions.
Zone diameter converts growth inhibition into a measurable result that supports comparisons among antimicrobial agents, concentrations, and microbial strains. A difference in diameter indicates that the tested conditions produced different areas where growth was prevented. The measurement is therefore most useful for comparative analysis rather than as an isolated description of microbial growth.
The antimicrobial agent, its concentration, and the microbial strain can each influence the measured inhibition zone. The agar provides the medium through which the compound diffuses, while the microorganisms create the growth pattern used for assessment. Comparing these variables under controlled conditions helps distinguish differences in antimicrobial activity from differences in the test setup.
The assay begins by spreading microorganisms across an agar surface. Antibiotic-containing discs or wells are then positioned so the compounds can be released into the medium and diffuse outward. After growth develops, the investigator measures the resulting inhibition zones and compares their diameters across the tested agents, concentrations, or strains.
Researchers apply antimicrobial diffusion measurement for antimicrobial screening, resistance investigations, and controlled evaluation of treatments. It can show whether different drugs or concentrations produce distinguishable inhibition patterns against selected microbial strains. In infection research, these comparisons help organize experimental evidence about how microbes respond to candidate or established antimicrobial conditions.
Within immunology and infection research, the method provides a controlled way to examine antimicrobial activity against microorganisms relevant to infection studies. Measuring inhibition zones supports comparisons between strains and treatments, while repeated testing under defined conditions can contribute to investigations of resistance and treatment performance. Its main outcome is a measurable comparative record of growth inhibition.