Light Activation
Light Activation - Related Videos
03:19
Inactivation of Bacteria Using Light-Activated Flavin Mononucleotide
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2025
Source: Cheng, C., et al. Inactivation of Pathogens via Visible-Light Photolysis of Riboflavin-5′-Phosphate. J. Vis. Exp. (2022)This video demonstrates a method for evaluating the phototoxic effects of flavin mononucleotide (FMN) on pathogenic bacteria. Bacterial cultures are exposed to increasing concentrations of FMN and illuminated with visible light to generate reactive oxygen species (ROS) that damage cellular components. The surviving bacteria are then quantified to assess the...
02:59
Light-Activated Treatment of Bacterial Biofilms Using a Photosensitizer Precursor
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2026
Source: Zhao, K., et al. An In Vitro Model to Study the Effect of 5-Aminolevulinic Acid-mediated Photodynamic Therapy on Staphylococcus aureus Biofilm. J. Vis. Exp. (2018)The video demonstrates a photodynamic therapy protocol to assess antibacterial effects on Gram-positive bacterial biofilms. Biofilms are divided into four groups: two receive a photosensitizer precursor, and two receive a buffer. All are incubated in the dark, followed by red light exposure to one precursor-treated group and...
08:47
Lighting Up the Pathways to Caspase Activation Using Bimolecular Fluorescence Complementation
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Cited by 1 •
2018
This protocol describes caspase Bimolecular Fluorescence Complementation (BiFC); an imaging-based method that can be used to visualize induced proximity of initiator caspases, which is the first step in their activation.
09:32
Light-mediated Reversible Modulation of the Mitogen-activated Protein Kinase Pathway during Cell Differentiation and Xenopus Embryonic Development
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Cited by 7 •
2017
This protocol describes an optogenetic strategy to modulate mitogen-activated protein kinase (MAPK) activity during cell differentiation and Xenopus embryonic development. This method allows for the reversible activation of the MAPK signaling pathway in mammalian cell culture and in multicellular live organisms, like Xenopus embryos, with high spatial and temporal resolution.
Measuring Circadian and Acute Light Responses in Mice using Wheel Running Activity
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Cited by 14 •
2011
This article will review methods that can be used to determine circadian function and light responsiveness in mice.
FAQs
Photon absorption provides the initial trigger for a light-sensitive molecule or photoreceptor. That absorbed energy can produce a structural rearrangement or chemical change, which then couples the light-sensitive component to a downstream biological signal. Depending on the system, the resulting signal may alter an ion channel, activate an enzyme, or influence gene expression.
The response depends on the molecular component connected to the light-sensitive system. Light activation can open ion channels, stimulate enzyme activity, or alter gene expression. These outputs allow researchers to influence cell activity through different biological routes, rather than relying on a single universal signaling mechanism. The selected output determines which cellular process can be examined.
Precise timing and location allow researchers to connect a controlled stimulus with a specific biological response. This is especially valuable when studying cell activity, neural circuits, development, or signaling pathways, where responses may depend on which cells are affected and when stimulation occurs. Light-controlled systems therefore support more targeted manipulation than broadly applied biological interventions.
These platforms apply the same general control principle to different biological targets. Optogenetics is used to manipulate cell activity, photoswitchable proteins provide light-responsive molecular control, and light-controlled drugs or biomaterials extend the approach to therapeutic or material-based systems. Their distinction lies primarily in the controlled component and the biological or translational setting in which it operates.
In optogenetics, researchers use light-responsive biological systems to manipulate cell activity with precise timing and location. This makes it possible to examine how changes in selected cellular activity relate to neural-circuit behavior. The approach is useful for linking molecular light responses to larger-scale biological functions without treating neural activity as an undifferentiated process.
Light activation can be applied to studies of development and signaling pathways, where controlled stimulation helps researchers examine how cells respond to molecular cues. Light-controlled drug and biomaterial systems also support therapeutic strategies by making biological or material behavior responsive to light. These applications connect basic studies of cellular regulation with efforts to design controllable interventions.