[Histonet] Phosphate buffered saline (PBS) with and without Ca andMg

[Christine Mather]

I am using PBS for making paraformaldehyde fix and also for 30% sucrose for
cryoprotecting tissues for both immunostaining and for conventional
histochemistry. I have the idea that the calcium and magnesium is required
when you are working with tissues as opposed to cells, since the Ca and Mg
are important for cell adhesion. With cell culture you want the cells to
stay separate so that's when to use the Ca/Mg free PBS. Am I correct?

For the sucrose, which is used on fixed tissue, would it still be necessary
to use PBS with Ca/Mg, since now the tissues are fixed they should not
dissociate if Ca/Mg free PBS?

-----Original Message-----
From: Gayle Callis [mailto:gcallis <@t> montana.edu]
Sent: Friday, January 23, 2004 2:41 PM
To: cmather <@t> origentherapeutics.com
Subject: Re: [Histonet] Phosphate buffered saline (PBS) with and without
Ca andMg


I presume you are using the PBS for immunostaining?  You did not say what
application was needed. We use Dulbeccos PBS without Ca and Mg for
immunostaining of all kinds.  For Beta Galactosidase or Beta Gal stained
tissue sections/whole lungs, the Dulbeccos has Mg added, probably to aid
enzyme reaction and the method has stringent directions.

People who do cell cultures and some other molecular biology applications
in our department sometimes use Dulbeccos PBS with the Ca and Mg added as
essential nutrients? during cell growth. Not being a cell culture type, I
may have not answered this completely.

I think for most immunostaining purposes, rinses, etc, plain PBS is the
standard reagent unless otherwise specified for some special enzyme or
other method protocol. If a method calls for Mg and Ca, then you need it.

At 02:21 PM 1/23/2004 -0800, you wrote:
>What are the essential differences in the uses of PBS with and without
>calcium and magnesium. Why would you use one in favor of the other?
>
>Christine.
>
>biotech employee
>
>
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Gayle Callis
MT,HT,HTL(ASCP)
Research Histopathology Supervisor
Veterinary Molecular Biology
Montana State University - Bozeman
PO Box 173610
Bozeman MT 59717-3610
406 994-6367 (lab with voice mail)
406 994-4303 (FAX)