Just a remark (not really on confocal microscopy),

To help prevent damage from freeze/thaw cycles one can use portable -20C
coolers. One can keep the antibodies/enzymes in the freezer in these units
(passive ones) and these should help keep the sensitive substances frozen,
even if the rest of the freezer thaws.
I have not tested this idea in practice, since I use these units to keep
sensitive solutions outside of the freezer for a few hours. However, many
of the manufacturers state this as one of the uses of these units.

Sincerely,
Daniel Gitler


>I agree with Martin overall - we use a really big range of secondaries
>(anti mouse / sheep / rabbit / rat conjugated to AMCA / Cy3 / Texas Red
>/ Cy5 / FITC /biotin / Alexas etc). We have found consistently over many
>years that you can get away with one freeze / thaw cycle as long as the
>volume is small (eg up to about 5 microlitres), there is a bit of
>glycerol in in the mix, and you use at least a -20C freezer.
>
>IAN
>
>
>Martin Wessendorf wrote:
>>
>> Tom Phillips wrote:
>> >
>> > The other big problem with -20 freezers is that they so often are
>> > "frost-free" these days.  The auto defrost cycles on these types of
>> > freezers are very tough on antibodies and sensitive enzymes.  I
>> > believe Jackson recommends diluting their antibodies in 50% glycerol
>> > if you want to store at -20 so that they don't "freeze" but yet are
>> > kept cold.  I don't know if that limits the damage by a frost-free
>> > freezer but do know that the molecular biology types all stress that
>> > their enzymes diluted in glycerol are still very labile if stored in
>> > a frost-free freezer.
>>
>> We typically store ours at -20 in glycerol and have no problems.  It's a
>> good compromise, since you can pipette out just what you need.
>>
>> Martin
>> --
>> Martin Wessendorf, Ph.D.                        office: (612) 626 0145
>> Associate Professor                             lab:    (612) 624 2991
>> Dept. Neuroscience                      Preferred FAX:  (612) 624 8118
>> University of Minnesota                 Dept FAX:       (612) 626 5009
>> Minneapolis, MN  55455                e-mail: [log in to unmask]
>
>--
>Professor Ian Gibbins
>Anatomy & Histology
>Flinders University of South Australia
>GPO Box 2100, Adelaide, SA 5001
>Australia
>
>Phone:  +61-8-8204 5271
>FAX:    +61-8-8277 0085
>Email:  [log in to unmask]


------------------------------------------------------------
Daniel Gitler
Department of Neurobiology
Box 3209
Duke University Medical Center
Durham, NC 27710
USA
Tel 1-919-681-6165
Fax 1-919-681-9866