When you sample I think you should take three subsamples for the different extractions (collagen, DNA, carbonate). For collagen stable isotope analysis it is very important to remove as much of the added organic carbon as possible. Collagen will survive strong acid, weak alkali, and most solvent treatments, so you can use quite vigorous methods to remove the consolidant in that subsample. For DNA I think the extraction can be done in the presence of the consolidant without attempting to remove it from the subsample. The same is probably true for carbonate, as acrylic polymers probably won't generate CO2 when exposed to concentrated phosphoric acid. If there is doubt about that, then a strong bleach treatment to remove all organic carbon may be needed.
However, with 30-year old consolidant there is likely to be extensive cross-linking and the removal will not necessarily be possible following the manufacturer's instructions. You should be prepared to sacrifice some bone for technique development and optimisation. It is not always possible to entirely remove acrylic polymers from bone, so it is quite possible you will not obtain reliable d13C measurements on collagen (see for example the work on Windover - Tuross & Fogel 1994).
Tuross N and Fogel ML (1994). Exceptional molecular preservation in the fossil record: the archaeological, conservation and scientific challenge. In Scott DA and Meyers P (eds) Archaeometery of Pre-Columbian Sites and Artefacts. Getty Conservation Institute: Marina del Rey, 367-80.
Best wishes
Andrew
--
Dr. Andrew Millard
e: [log in to unmask] | t: +44 191 334 1147
w: https://www.dur.ac.uk/archaeology/staff/?id=160
https://www.dur.ac.uk/imems/
Director of the Institute of Medieval &
Early Modern Studies, and
Senior Lecturer in Archaeology,
Durham University, UK
> -----Original Message-----
> From: Ancient DNA List [mailto:[log in to unmask]] On Behalf Of
> John Dudgeon
> Sent: 02 February 2017 19:57
> To: [log in to unmask]
> Subject: [ANCIENT-DNA] Best solvent for sample cleaning and DNA
> preservation
>
> Hi All,
>
>
>
>
> We have a collection of archaeological bones recovered from damp
> geological sand about 35 years ago, which we are preparing for collagen
> and carbonate stable isotope analysis. During recovery, the samples
> were consolidated with Acrysol WS-24 (Primal WS-24 in Europe), a
> polyacrylic acid suspension used by archaeologists and curators for its
> stability, non-toxicity and application on wet samples. We would like
> to remove this consolidant prior to sample preparation to avoid
> external carbon signals, but would also like to preserve the endogenous
> DNA molecules for later extraction.
>
>
>
>
> The manufacturer suggests removal with slightly alkaline solutions, and
> our question is which buffer solution would be better for DNA
> preservation in a 24 h soak with rotation. The options we’ve considered
> are TBS (50 mM Tris, 150 mM NaCl), low TE (10 mM Tris, 1 mM EDTA) and
> 0.4 M EDTA, all at pH 8.0. EDTA seems prudent to complex Mg, but we
> don’t want to do any demineralization on the specimens prior to
> sampling for isotopes.
>
>
>
>
> In the expected case of none here having experience with removal of
> this particular consolidant, can anyone give some opinions on the use
> of any of these (or other) solvent preparations for best preservation
> of nucleic acids in these specimens?
>
>
> Regards,
>
> John
>
>
> --
>
> John V. Dudgeon, Ph.D.
> Associate Professor, Department of Anthropology
> Director, Center for Archaeology, Materials and Applied Spectroscopy
> (CAMAS)
> -----------------------------------------------------------------------
> -------------------------
> Idaho State University, 921 S. 8th Avenue, Stop 8005, Pocatello, ID
> 83209-8005
> Phone: (208) 282-3862 - FAX: (208) 282-4944
> http://anthropology.isu.edu/dudgeon.shtml
> http://www.isu.edu/camas/
>
|