[NHCOLL-L:1792] Re: Liquid nitrogen field collections and materials used

[Ross MacCulloch]

Hi Lex:

We've never collected whole "large" specimens, so I can't offer much help there. By "large" I mean animals that won't fit into a cryovial - we've collected many whole "small" vial-sized specimens. Perhaps if you elaborated on your subsampling procedures, we could suggest field protocols that would eliminate the need for freezing entire fishes. I assume that the tried-and-true "freeze a chunk of tissue & pickle the rest" method is not adequate for your purposes.

We stopped using Nunc brand vials for several reasons: 1) they are more expensive than other brands; 2) the white writing area consists of white "paint" applied to the very smooth exterior tube surface - this sometimes wears away, taking the writing with it, especially if the LN2 tank is transported a lot and the tubes jostle one another in the tank. (I've found that Sharpie ink adheres to the white surface better than the white surface adheres to the tube) 3) the thread for screwing on the cap is on the inside of the tube. Removing frozen tissue from this type of vial requires "unscrewing" the frozen gob of tissue from the vial. This is very annoying.

We now use tubes with the thread on the outside of the vial (and on the inside of the cap). They are transluscent, with a roughened square patch for writing. I personally have had no trouble with reading field numbers which are written on this patch (the penmanship of the field workers aside), regardless of the amount of handling that the LN2 tank has undergone. We use Sharpies.

We purchase these cryovials from Diamed, a lab supply company here in Toronto. I doubt that the vials are made locally, though, so your suppliers should be able to come up with some. I can mail you a sample if you wish. They come in 1.5 and 4.5 ml sizes, with a choice of blue or red caps. They're lots cheaper than Nunc tubes, too.

Some colleagues take the precaution of scratching the field number into the plastic of the vial using a pointy metal scriber.  I have never found this necessary, but if you want to be absolutely sure.....

Cheers,
Ross

Ross D. MacCulloch
Assistant Curator - Herpetology
Centre for Biodiversity and Conservation Biology
Royal Ontario Museum
100 Queen's Park
Toronto
Ontario M5S 2C6

>>> "Alexandra M. Snyder" <amsnyder at unm.edu> 11-Dec-02 1:04:41 pm >>>
I am trying to come up with materials that can be used in the field to 
collect whole fishes (small) for tissue subsampling.  These materials must 
hold up in liquid nitrogen.

Currently, I am testing the Tyvek 1422A, the light weight variety, for bags 
and the Uniball Deluxe pen or Sanford "Sharpie Industrial" inks for the 
outside info.  The idea is to write the info on the Tyvek bag (the sides 
sealed with a heat sealer we use for 4 mil bags), place the whole fish in 
the bag and secure the top (some how).  Then it all goes into the liquid 
nitrogen bath.

Normally, I receive these collections in tinfoil packets.   The researcher 
attempts to write the field number on the outside of the tinfoil packet 
using a pen.  This is not always successful and, since I cannot convince 
anyone to use internal labels, I need to come up with something that will 
be "permanent" or at least permanent enough for me to retrieve the 
information (field number) when pulling the fishes from the liquid 
nitrogen.

I am looking for more ideas or advice on materials for whole specimen field 
collections that are put into liquid nitrogen and how to secure field data 
to these collections.  I could also use some advice on a good pen that will 
write on the plastic nunc tubes and hold up in the liquid nitrogen.  The 
thicker nibs are problematic and the Sharpie Industrial has not passed my 
tests.  Again, the researchers will not put a backup label inside the nunc 
tube with the tissue leaving me to second guess the handwriting or the 
faded pen ink.

Thank you for your attention to this question.

Lex
================================
Alexandra M. Snyder, Collection Manager
Division of Fishes
Museum of Southwestern Biology
University of New Mexico
Albuquerque NM 87131 USA
Ph 505.277.6005  Fax 505.277.3218
amsnyder at unm.edu