Dr. Duncan Clark duncan at nospam.demon.co.uk
Tue Jul 7 09:24:16 EST 1998

In article <35A22449.490A67AC at uni-koeln.de>, akd38 <Holger.Stalz at uni-
koeln.de> writes
>I'm looking for a method of isolating  genomic DNA from the siliceous
>sponge Geodia cydonium. I tried the QIAGEN Blood & Cell culture Kit but
>wasn't succesful at all.
>The main problem is caused by the silica pieces which I achieved after
>producing single cells and the gemmulae which couldn't be lysed due to
>the membrane associated silica pieces.
>If anyone had ever heard of someone who had ever lysed any kind of
>membranes of siliceous sponges, it would be nice if YOU could inform

Even if you manage to lyse the sponge, the silica is going to bind the
DNA if any salt is present ie this is the basis for all GeneClean and
similar silica DNA prep kits. You will have to back extract the silica
particles with say just TE, maybe at 65C to get at the DNA.
Alternatively make sure you get rid of the silica by low speed
centrifugation at the start (so long as this doesn't remove your sponge
as well!). 

The problem with being on the cutting edge is that you occasionally get 
sliced from time to time....

Duncan Clark
DNAmp Ltd.
TEl/FAX 01252376288

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