Fluorescein diacetate fluorescence, seemingly largely cytoplasmic, gave
the pHi value of 6.9-7.0 years ago (no effect seen of pHo using
phosphate buffers spanning pH5- pH7.5)
Ratner (1986), Nature 321, pp180-2. (also not in PubMed).
http://www.nature.com/nature/journal/v321/n6066/pdf/321180a0.pdf
The lower values observed for developing cell types, despite my best
efforts at the time, may well be spuriously low as a result of
fluorescein diacetate accumulation/acidification. All covered in Kei's
1988 paper also reviewing the earlier literature.
David
Dear Ralph,
Marin and Rothman (1980, JCB 87, 823) give ionic contents of A3
vegetative cells measured by flame photometry (Na 8.2, K 46.5 meq/L).
Maeda (1983, Bot Mag 96, 193) reports ionic contents of D. d. NC-4
vegetative cells by atomic absorption spectroscopy (35.0, 3.6, 10.6,
and 2.3 for K, Na, Mg, and Ca, respectively). She further
demonstrates the effects of external Na and K concentrations. I
measured Na, K and Cl of NC-4 and D. mucoroides veg cells by flame
photometry and chloridometry (unpublished) and obtained Na and K
values comparable to Maeda's values. The Cl concentration was always
about twice that of Na.
Cytosolic pH is most likely between 7 and 7.5. See appendix of Inouye
(1988, JCS 91, 109).
Maeda (1983)
http://springerlink.com/content/t106081564836261/fulltext.pdf
Inouye (1988)
http://jcs.biologists.org/cgi/reprint/91/1/109
These papers somehow cannot be found on Pubmed.
Best wishes,
Kei
_____________________________
Kei Inouye
Department of Botany
Graduate School of Science
Kyoto University
Sakyo-ku, Kyoto 606-8502
Japan
_____________________________
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http://cosmos.bot.kyoto-u.ac.jp/csm/
_____________________________
On 2010/06/24, at 20:54, Ralph Gräf wrote:
> Dear Dicty Researchers,
>
> I was trying to find a publication where somebody has measured or
> estimated the cytosolic salt concentrations of prominent cations
> and anions but I was not successful. I doubt that the commonly used
> low ionic strength Soerenson phosphate buffer reflects a
> physiological situation for cytosolic proteins. We would like to
> use an optimal physiological buffer for cytosolic proteins with
> regard to pH, ion concentration and ion composition. Any helpful
> hints are welcome.
>
> All the best,
>
> Ralph
>
>
> ---------------------------------------------------------
>
> Prof. Dr. Ralph Gräf
>
> University of Potsdam
> Institute of Biochemistry and Biology
> Department of CELL BIOLOGY
>
> Karl-Liebknecht-Strasse 24-25, Haus 26
> 14476 Potsdam
> Germany
>
> Tel.: +49-(0)331 9775520
> FAX: +49-(0)331 9775522
>
> http://www.bio.uni-potsdam.de/professuren/zellbiologie/aktivitaten
--
David I. Ratner
Department of Biology
Amherst College, Amherst MA, USA 01002-5000
phone: 413-542-2248
fax: 413-542-7955
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