The technique of JC-1 staining has been developed with the intent to detect DY in intact, viable cells. For this purpose JC-1 acts as a marker of mitochondrial activity, since the formation of J-aggregates, which give red emission, is reversible. Cells with high DY are those forming J-aggregates, thus showing high red fluorescence. On the other hand, cells with low DY are those in which JC-1 maintains (or re-acquire) monomeric form, thus showing only green fluorescence. - [Read Analysis of Mitochondrial Membrane Potential with the Sensitive Fluorescent Probe JC-1]
Flow cytometers must be calibrated prior to fluorescence intensity measurements because of inherent instrument variability. To correct for this variability, a standard particle (fixed chicken red blood cells, or CRBCs) must be analyzed on the instrument prior to each experiment and photomultiplier tube (PMT) voltages adjusted accordingly to place the CRBC fluorescence emission peaks into predetermined target channels. - [Read Calibration of Becton Dickinson Flow Cytometers for Relative Fluorescence Intensity Measurements]
Data for fluorescent dye properties. Includes: Fluorochrome, Excitation in(nm), Emission in (nm) and Color Application. - [Read Fluorescent Dye Properties Data]
Fluorescent dyes absorb light at certain wavelengths and in turn emit their fluorescence energy at a higher wavelength. Each dye has a distinct emission spectrum, which can be exploited for multicolor analysis. eBioscience antibodies are available conjugated to a wide variety of fluorochromes. - [Read Fluorescent Dyes for Flow Cytometric Analysis]
Positron emission tomography (PET) is a established quantitative and noninvasive imaging modality. With the PET reporter gene (PRG)/PET reporter probe (PRP) system, based on a mutant form of herpes simplex virus 1 thymidine kinase (HSV1-sr39tk), the PET signal is directly proportional to the enzymatic activity of sr39TK9-14. In this protocol, we describe in detail a method for reporter gene labeling of islets and quantitative scanning using a reporter probe. - [Read In Vivo Functional Real-Time Imaging of Transplanted Islets Using Positron Emission Tomography (PET)]
Article presents an introduction to fluorescence microscopy. Includes: Fundamentals of Excitation and Emission; Stokes' Shift; Fading, Quenching, and Photobleaching; Fluorescence Light Sources; Filter Terminology; The Fluorescence Light Budget; Detecting Single Molecules. - [Read Introduction to Fluorescence Microscopy]
Assay measures cell viability. It is a two-color fluorescence assay that simultaneously determines Live cell number and Dead cell number. This protocol is designed for use with the GEMINI XS Microplate Spectrofluorometer, a multi-well plate scanner with dual excitation/emission capabilities, but the assay is also adaptable for flow cytometry and fluorescence microscopy. Includes: Cell Culture; Preparation for the Assay; Live/Dead Assay; Reading the Plate; Data Analysis; Alternative protocol. - [Read Live/Dead Assay for Cell Viability Protoco]
The more commonly available single-laser cytometers can also be used to measure multicellular conjugates, but due to overlaps in emission spectra, the extent of labeling cells with fluorophores must be controlled much more carefully when the single-laser machines are used. This protocol describes the labeling of cells and analysis of conjugates with either dual-laser or single laser flow cytometers. - [Read Measurement of Intercellular Conjugates by Flow Cytometry Protocol]
Using excitation at 365 nm and measuring emission at 455 nm, the amount of 4-MU produced can be quantified. Under these conditions, background fluorescence from the substrate is negligible, especially if the appropriate filter is selected. - [Read Quantitative GUS Activity Assay of Plant Extracts]