Fluorescence Digital Image Gallery

Transformed African Green Monkey Kidney Fibroblast Cells (COS-7)

Static or complex quenching arises from non-fluorescent complexes formed between the quencher and fluorophore that serve to limit absorption by reducing the population of active, excitable molecules. This effect occurs when the fluorescent species forms a reversible complex with the quencher molecule in the ground state, and does not rely on diffusion or molecular collisions. In static quenching, fluorescence emission is reduced without altering the excited state lifetime. A fluorophore in the excited state can also be quenched by a dipolar resonance energy transfer mechanism when in close proximity with an acceptor molecule to which the excited state energy can be transferred non-radiatively. In some cases, quenching can occur through non-molecular mechanisms, such as attenuation of incident light by an absorbing species (including the chromophore itself).

The cytoskeletal F-actin network and nuclear DNA present in the culture of COS-7 cells featured in the digital image above were targeted with Alexa Fluor 488 conjugated to phalloidin and the intercalating dye propidium iodide, respectively. The specimen was also labeled with Alexa Fluor 350 conjugated to wheat germ agglutinin, a fluorescent lectin that selectively binds to sialic acid residues, which are found in both mucoproteins and glycoproteins. Images were recorded in grayscale with a QImaging Retiga Fast-EXi camera system coupled to an Olympus BX-51 microscope equipped with bandpass emission fluorescence filter optical blocks provided by Omega Optical. During the processing stage, individual image channels were pseudocolored with RGB values corresponding to each of the fluorophore emission spectral profiles.

View a larger image of the African green monkey kidney (COS-7) cells.

© 1995-2013 by Michael W. Davidson and The Florida State University. All Rights Reserved. No images, graphics, software, scripts, or applets may be reproduced or used in any manner without permission from the copyright holders. Use of this website means you agree to all of the Legal Terms and Conditions set forth by the owners.
This website is maintained by our
Graphics & Web Programming Team
in collaboration with Optical Microscopy at the
National High Magnetic Field Laboratory.
Last modification: Thursday, Oct 14, 2004 at 09:34 AM
Access Count Since July 16, 2004: 7673
Microscopes, fluorescence filters, and digital imaging equipment provided by:
Visit the Olympus Microscopy Resource Center website. Visit the Omega Optical website. Visit the QImaging website.