[NHCOLL-L:4510] RE: resitivity for water used in wet collections?

[Dirk Neumann]

I wouldn't recommend this for many reasons already discussed here 
(leaching & decolouration, of specimens, etc.). Methanol denatured 
alcohol should be similar to Isopropyl alcohol, at least far better then 
camphor or ketones added in other countries. If the specimens are 
already stored in this alcohol, leave them. The DNA of the specimens 
included is degraded anyway, changing the alcohol is not improving the 
situation but possibly making things worse for the specimens. But you 
should consider to take separate tissue samples preserved in 96 % 
Ethanol from future specimens.

All the best
Dirk



BESSON Ludovic schrieb:
> In our collection we used 70% (obtained with denatured 95 %EtOH with 2% methanol) : Did I Must change all ethanol in wet collection ?
>
> Best regards 
>
> Ludovic Besson
> Responsable des collections
> Muséum Gabriel Foucher
> Les Rives d'Auron - Allée Ménard
> 18000 Bourges (France)
> Tél.: 02 48 65 37 34
> http://www.museum-bourges.net/
>
>
> -----Message d'origine-----
> De : Dirk Neumann [mailto:Dirk.Neumann at zsm.mwn.de] 
> Envoyé : lundi 7 septembre 2009 15:52
> À : BESSON Ludovic
> Cc : NHCOLL-L at lists.yale.edu
> Objet : Re: [NHCOLL-L:4508] RE: resitivity for water used in wet collections?
>
> Dear Ludovic,
>
> YES; depending on the denaturing agent, how polar it is and for how long 
> the tissue are stored in the denatured alcohol. An exemption would be 
> Isopropyl alcohol as denaturing agent.
> Polar additives tend to degrade the DNA-helix, resulting in low quality 
> row-DNA extracts and short fragments reading frames after amplification, 
> so that internal primer might be necessary.
>
> The same obviously applies for highly concentrated (technically dried) 
> absolute Ethanol  (e.g. 99.8 %). Residual Benzines used for water 
> extraction above Ethanol concentrations of 96% seems to degrade the DNA, 
> too. We had problems with tissues after being stored for 1 year in 99.8 
> % Ethanol. We changed our tissue collection to (destilled) Ethanol 
> (96%). This concentration is sufficient for DNA preservation & storage 
> if you don't exceed the ration 1:3 for initial preservation (1 part 
> tissue, 3 parts Ethanol).
>
> Hope this helps
> Dirk
>
>
> BESSON Ludovic schrieb:
>   
>> Is it a problem when you used for your wet collection denatured 
>> alcohol? Is it a problem for future DNA analyse ?
>>
>>  
>>
>> Best regards
>>
>>  
>>
>> Ludovic Besson
>>
>> Responsable des collections
>>
>> Muséum Gabriel Foucher
>>
>> Les Rives d'Auron - Allée Ménard
>>
>> 18000 Bourges (France)
>>
>> Tél.: 02 48 65 37 34
>>
>> http://www.museum-bourges.net/
>>
>>     
>
>
>   


-- 
Dirk Neumann

Tel: 089 / 8107-111
Fax: 089 / 8107-300
email: Dirk.Neumann(a)zsm.mwn.de

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---------

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