Fluorescence Ratio Imaging of Cytoplasmic pH in Plant Cells Using Fluorescein Diacetate
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Authors
Spillard, Kristine S.
Issue Date
1990
Type
Thesis
Language
en_US
Keywords
Alternative Title
Abstract
Cytoplasmic pH is extremely important in the regulation of a variety of
cellular processes. Microspectrofluorometry and fluorescence ratio imaging
has been used to measure cytoplasmic pH in soybean ( Glycine max L. )
protoplasts and suspension cells, using the pH-sensitive probe fluorescein
diacetate (FDA). The initially non-fluorescent derivative of fluorescein, FDA, is
freely diffusible across the cell membrane into the cytoplasm where cellular
esterases release the highly fluorescent chromophore. The fluorescein is
retained in the cytoplasm and slowly diffuses out of the cells. pH measurements
revealed a relatively acidic pH in normal protoplasts and cells, 6.4 + 0.2 and
6.5 ± 0.3 respectively, with a general increase in pHcyt upon treatment with
weak base, and decrease with weak acid. Fluorescence ratio imaging of onion
root epidermal cells shows higher cytoplasmic pH's from 6.0-7.0. In all cases
ratio imaging revealed spatial variations of pH within the cytoplasm and pH
differences between the cytoplasm and the nucleus were apparent.
Description
vi, 36 p.
Citation
Publisher
Kalamazoo College
License
U.S. copyright laws protect this material. Commercial use or distribution of this material is not permitted without prior written permission of the copyright holder.