Dye Diffusion Assay
Dye Diffusion Assay - Related Videos
06:01
A Dye Release Assay to Quantify Enzymatic Activity of Antimicrobial Proteins
0 Views •
2025
This video demonstrates the dye release assay for quantifying the enzymatic activity of antimicrobial proteins. The antimicrobial protein degrades the bacteria's dye-labeled cell wall and releases the dye molecules turning the solution blue. The absorbance of the solution correlates with the enzymatic activity of the antimicrobial protein.
03:16
Phospholipase Activity Assay: A Gel Diffusion Assay to Determine Phospholipase Activity in Crude Venom Extract from Anthopleura dowii
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2025
In this video, we demonstrate an assay to establish the presence of phospholipase in the crude venom extract from Anthopleura dowii—a marine sea anemone. The assay utilizes an agarose gel diffusion technique, in which the enzyme phospholipase diffuses and breaks down phospholipids incorporated in the solid media in a radial manner.
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.
06:13
Dyeing Insects for Behavioral Assays: the Mating Behavior of Anesthetized Drosophila
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Cited by 8 •
2015
This protocol describes a simple, cost effective way to individually identify Drosophila or other insects. Demonstration data investigating mating success across three species of Drosophila show that this method is comparable or better than the use of CO2 anaesthesia.
03:31
Diffusion and Osmosis - Concepts
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2019
Cell Membranes and Diffusion In order to function, cells are required to move materials in and out of their cytoplasm via their cell membranes. These membranes are semipermeable, meaning that certain molecules are allowed to pass through, but not others. This movement of molecules is mediated by the phospholipid bilayer and its embedded proteins, some of which act as transport channels for molecules that otherwise would not be able to pass through the membrane, such as ions and carbohydrates.
FAQs
Although individual dye molecules move randomly, the population shows a net movement from higher concentration toward lower concentration. A larger concentration difference creates a stronger driving condition for visible spreading, while the gradient decreases as the dye becomes more evenly distributed. This pattern connects changing color distribution with passive transport.
Diffusion rate depends on temperature, travel distance, concentration gradient, and the properties of the surrounding material. These variables must be considered when comparing observations, because a change in spreading may reflect altered conditions rather than a difference in the dye itself. Tracking these factors supports more accurate interpretation of color movement.
The assay can compare how a colored solute moves through different media. A gel provides a material in which spreading can be observed, whereas a membrane can be examined for permeability, meaning how readily the solute passes through it. Differences in movement help connect material properties with transport behavior in biological systems.
A basic procedure introduces a colored solute into a selected medium, allows time for spreading, and observes or measures the resulting color distribution. Researchers can compare how far or how quickly the dye travels under specified conditions. Repeating this approach with gels or membranes makes differences in diffusion easier to examine.
The distance traveled provides an observable measure of how far the solute has spread through the medium. Interpreting that distance alongside elapsed diffusion and the tested conditions can show whether changes in temperature, concentration gradient, or material properties influenced movement. It therefore helps convert visible color changes into comparative transport information.
Researchers can examine how readily a colored solute passes through a membrane and compare the resulting spread with movement through another material. Greater or lesser transport provides comparative information about permeability, rather than simply showing color change. This application helps characterize how surrounding materials influence molecular movement in a controlled model.
The assay links an easily observed color pattern with passive transport, giving students and researchers a model for molecular movement in cells and physiological systems. Comparisons involving gels or membranes extend that model by showing how the surrounding material affects spread. Results can therefore support investigations of transport principles without directly observing individual molecules.