How can we get tissue samples for DNA studies from live marine shelled gastropods (small but not microscopic) when the shells have a narrow aperture, a small aperture and/or an operculum.
Although we want the tissue sample, at the same time we need to preserve both the shell and as much as possible of the soft parts as a voucher specimen.
Suggestions:
* Micowaving?
* Menthol?
Thanks!
The best method is microwaving, here you have a recent publication explaining how to do it and why: http://onlinelibrary.wiley.com/doi/10.1111/1755-0998.12231/abstract
This is the reference:
L. A. Galindo1,†,*, N. Puillandre1, E. E. Strong2 and P. Bouchet3. 2014. Using microwaves to prepare gastropods for DNA barcoding. Molecular Ecology Resources, Volume 14, Issue 4, pages 700–705.
That is the method we use for Pleuroceridae and have gotten great results.
Thank you Manuel and Art.
Unfortunately and surprisingly, there is no microwave here although there are two kitchens.
if they are still in sea water and relatively happy, you can slowly (very slowly) heat it up to 40 degrees.. (put it into a larger container with warm water). Snails will crawl around and die within short time after temperature becomes too hot. Than fix and preserve
That's an interesting method, and easy to do probably although one would have to watch the timing carefully because rotting starts immediately after death.
- Thanks Frank for the suggestion.
These answers are oriented at finding the most efficient method. I would consider DNA from saliva during feeding. Always less force.
Thanks Lachlan. Unfortunately we are on a 3-week expedition to the Caribbean island of Sint Eustatius, and so we don't have a lot of time or very much equipment. There is no aquarium, for example.
We will have to compromise I think and only take samples from the gastropods that are the easiest.
We have also used a tea strainer and placed the live snails in boiling/very hot water for 10-12 seconds which will have the same results as microwave.
There are so many good answers here that it is possible that they should be compared. I have removed my suggestion about retrieving gametes, because the nucleic acids would be single stranded (RNA) not DNA. This brings my corner of the suggestion-field to one head: Obtain a saliva inducing chemical (and handle with care). If this sounds feasible, see references 5, 9 and 22 of:
Babu JP, Abraham SN, Dabbous MK and Beachey EH (1986) Interaction of a 60-Kiladalton D- Mannose Containing Salivary Glycoprotein with Type 1 Fimbriae of Eschericia coli. Infection and Immunity 54(1), 104-108.
http://europepmc.org/backend/ptpmcrender.fcgi?accid=PMC260123&blobtype=pdf.
Accessed on: 13/06/2015.
there is still good old Magnesioum chloride. I volume of crystals to 13 volumes of FRESH water. Works beter when cold. Be patient, depending on the droup, the snail will get out of the shell in some time.
Thank you very much Yu. I will see if we have any Magnesium chloride in this lab. We are away on a small Caribbean island, and we don't have so many supplies with us.
Hi, you can try Epsom salt in substitution of magnesium chloride. Common in in small drug stores.
Thanks so much Prof Rios.
We have pretty much worked out a way now that is working OK for most species. Thank you to everyone for the assistance.
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