Fluorescence Intensity Measurements
Fluorescence Intensity Measurements - Related Videos
09:39
A Behavioral Assay to Measure Responsiveness of Zebrafish to Changes in Light Intensities
0 Views •
Cited by 222 •
2008
We developed the Visual-Motor Response to quantitate the motor output of larval zebrafish in response to light increments and decrements. We also examined zebrafish vision mutants, including the no optokinetic response (nrc) mutants, which were thought to be completely blind when tested by another vision assay, the optokinetic reflex.
14:39
Measuring Phagosome pH by Ratiometric Fluorescence Microscopy
0 Views •
Cited by 26 •
2015
Phagosomal pH influences phagosome maturation, oxidant production, phagosomal killing as well as antigen presentation. Here we describe a ratiometric method for measuring time-course and endpoint pH changes in individual phagosomes in living phagocytes using fluorescence microscopy.
08:17
Fluorescent Nanoparticles for the Measurement of Ion Concentration in Biological Systems
0 Views •
Cited by 24 •
2011
Fluorescent nanoparticles produced in our lab are used for imaging ion concentrations and ion fluxes in biological systems such as cells during signaling and interstitial fluid during physiological homeostasis.
04:02
An Assay to Measure the Accumulation of a Fluorescent Antibiotic Probe in Bacterial Cells
0 Views •
2025
This video demonstrates an assay to measure the accumulation of a fluorescent antibiotic probe in bacterial cells. Exposure to an efflux pump inhibitor disrupts the transmembrane proton gradient in bacterial cells, upon which a fluorophore-conjugated antibiotic is added. Inhibition of efflux pumps due to the disrupted proton gradient causes accumulation of the antibiotic inside the bacteria. Bacterial cells are lysed, and the fluorescence intensity is measured to confirm antibiotic accumulation.
07:03
In Situ Measurement of Vacuum Window Birefringence using 25Mg+ Fluorescence
0 Views •
2020
Presented here is a method to measure the birefringence of vacuum windows by maximizing the fluorescence counts emitted by Doppler cooled 25Mg+ ions in an ion trap. The birefringence of vacuum windows will change the polarization states of the laser, which can be compensated by changing the azimuthal angles of external wave plates.
FAQs
An excitation event raises a fluorophore to a higher electronic state, and its return toward the ground state produces emitted photons that the instrument collects. The measurement therefore depends on both the light used to excite the sample and the emitted light reaching the detector. Selecting and maintaining appropriate instrument settings helps make readings comparable across samples.
Photobleaching permanently reduces the available fluorescent signal during observation, whereas quenching lowers emission through interactions or conditions affecting the fluorophore. Background signal adds light that does not arise from the target. Because all three can distort apparent intensity, controlled acquisition and suitable background handling are essential when comparing biological samples.
Fluorescence intensity can indicate fluorophore amount only when relevant conditions remain controlled. Changes in excitation, detection settings, background, quenching, or photobleaching can alter the reading without a corresponding change in concentration. Calibration and standardized acquisition allow investigators to distinguish biological differences from measurement variation, strengthening quantitative comparisons between samples.
A fluorescence spectrometer provides an instrument-based way to collect emission from a sample, while a fluorescence microscope supports measurements within cellular images. Both rely on excitation and photon collection, but their biological uses differ in emphasis: spectrometric readings support protein or nucleic-acid assays, whereas microscopy helps examine fluorescence in cells and monitor molecular changes.
Researchers should establish consistent excitation and detection settings, calibrate the measurement system, and acquire samples using the same standardized conditions. They should also account for photobleaching, quenching, and background signal before comparing readings. This workflow reduces technical variation and makes changes in fluorescence more interpretable as differences among biological samples.
Protein and nucleic-acid assays can use fluorescence intensity to assess fluorescent signals associated with these biomolecules. The approach is also applicable to cellular imaging and monitoring molecular interactions. Its sensitivity makes changes in biological samples easier to detect, provided investigators control acquisition conditions and interpret signal changes alongside possible background, quenching, or photobleaching effects.
Changes in emitted intensity can be followed when fluorescently labeled biological components participate in molecular interactions. The resulting signal provides a way to monitor changes across samples or experimental conditions, but interpretation requires consistent acquisition and attention to quenching, photobleaching, background, and instrument settings. These controls help separate interaction-related fluorescence changes from measurement artifacts.