To characterize and validate the gluteraldehyde fixation method, a live amoeba syringe-loaded with Rhodamine-N58C-profilin-II was monitored in a flow cell as the fixative was introduced. This time series of cooled CCD fluorescence micrographs shows a cell as it is being fixed in 20% Dulbecco's PBS at pH 6.5 containing 1% glutaraldehyde at room temperature. See publication below for details. Live cells were observed with a Zeiss Axiovert 135 fluorescence microscope. Electronic imaging of fluorescent specimens was performed using a Photometrics cooled, charge-coupled device (CCD) camera (PXL-1400) controlled with IPLab Spectrum 3.1P software (Scanolytics, Fairfax, VA) on Macintosh computers. Copyright © 1999 by Company of Biologists and reproduced/adapted with permission in 2011.