Rashmi,

Yes, you should use the needle for seeding.
The first thing to do is to seed your control drop to make sure that the  
needles
are not bicine, as this buffer can give needles at certain pH at high  
PEG400
concentrations.
Next (or at the same time) also seed other protein drops that you have  
already set up
under similar conditions. I recommend streak seeding, so that even if  
crystal growth
is slow you will see the streak line early on.

Enrico.

On Fri, 29 Apr 2011 12:43:21 +0200, anita p <[log in to unmask]> wrote:

> Hi,
> I had set up crystallization with a bicine  as buffer and peg 400 as
> precipitant. I used the detergent DDAO/LDAO as an additive to the
> crystallization drop (one of the hampton additive screen condition, it  
> says
> 5% on the vial)
> I have a clear drop and in the centre there is a shiny precipitate (looks
> like granules attached to eah other).
> Then I opened the drop to touch those granules with a needle, but
> suprisingly its like a skin and the skin surrounded my needle, and then  
> some
> how I was able to but back the skin in the ppt.
> orelse the drop is clear if I remove the skin from the drop.
> I couldnot see the same on the control drop with no protein and just  
> buffer.
> Does anyone have any experience with  such kind of of shiny skins on
> crystallization drops??
>
> Is it protein? Can I go forward and use it for seeding??
>
> Please suggest
> with regards
> Rashmi


-- 
Enrico A. Stura D.Phil. (Oxon) ,    Tel: 33 (0)1 69 08 4302 Office
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