From owner-celegans@net.bio.net Mon Oct 27 22:00:00 1997
Path: biosci!biosci!not-for-mail
From: cdarby@u.washington.edu (Creg Darby)
Newsgroups: bionet.celegans
Subject: Re: isolating C. elegans from soil
Date: 27 Oct 1997 18:58:19 -0800
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Re the method abstract below, I STRONGLY advise contacting the authors
first. I got hold of some colloidal silica and tried their technique,
which called for pH'ing the silica. When I did this, the silica congealed
in the bottle like agarose. I recall trying to call DuPont, which provided
the silica, and never getting a call back from the chemist I was referred
to. I didn't contact the authors of the cited paper for help because the
technique became irrelevant for my work.

Creg Darby                                     cdarby@u.washington.edu
Department of Genetics
Box 357360                                           lab: 206-543-9446
University of Washington
Seattle, WA 98195                                    fax: 206-543-0754


fabian@airmail.net (dave) writes:

>>CGC Bibliography Paper 1746
>>
>>A soil toxicity test using the nematode Caenorhabditis elegans and an
>>effective method of recovery.
>>
>>Donkin SG;Dusenbery DB
>>
>>    Citation: Archives of Environmental Contamination and Toxicology 25:
>>             145-151  1993
>>       Type: ARTICLE
>>      Genes:
>>   Abstract: A new method for recovering nematodes from soils in an
>>             efficient, reproducible, and non-destructive manner has been
>>             developed. It was used to conduct short-term soil toxicity tests
>>             using the soil-dwelling nematode Caenorhabditis elegans and
>>             several different soil types spiked with copper chloride. The
>>             recovery method, which involves centrifugation through a
>>             colloidal silica suspension, allows the nematodes to be
>>             extracted from the soil matrix so that lethality can be
>>             assessed. The nematodes are unharmed by the recovery procedure,
>>             and both live and dead individuals are recovered with high
>>             efficiency (well over 80%), allowing reproducible
>>             concentration-response curves to be made after a 24-h exposure.
>>             The LC50s for copper were increased about tenfold by the
>>             presence of soil, and different soils had significantly
>>             different effects on toxicity. Toxicity of copper ion was also
>>             influenced by the concentration of sodium chloride and potassium
>>             chloride in the test solution, and the presence of bacteria
>>             increased the toxicity of copper ion in some soils. The LC50s in
>>             soil were close to the LC50 for the 2-week earthworm soil
>>             toxicity test, suggesting that a 24-h nematode toxicity test may
>>             be comparable to the 2-week earthworm test in terms of
>>             sensitivity.



>Does anyone have more informationg on this technique?


--
Creg Darby                                     cdarby@u.washington.edu
Department of Genetics
Box 357360                                           lab: 206-543-9446
University of Washington



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