[Zbrafish] Re: Problems in Tuebingen

Leviathan jason.cockington at adelaide.edu.au
Mon Jun 26 02:36:57 EST 2006


Well the standard procedure we use is as follows:

Embryos are collected either via a marble tray in a tank, or via a pair
mating, from tanks in the primary systems.

Unfortunately we are currently experiencing a problem with our main
systems as they seem to have some form of fungal growth.  We have not
been able to kill the fungus at this stage, as we are not currently set
up to allow a system shut down for mainetnance (this is something we
are working on at the moment).

The embryos are collected by pouring through a strainer, and then
transferring the embryos into a petri dish, where they are suspended in
Embryo Medium (3.43ml 4M NaCl, 0.54ml 1M KCl, 0.125ml 0.2M Na2HPO4,
0.22ml 0.2M K2HPO4, 1.0ml 1M CaCL2, 1.0ml 1M MgSO4, and 0.35g NaHCO3,
topped up to 1L with dH2O).

The petri dish is then placed at 28.5oC, and the water is replaced with
fresh EM daily, with any dead embryos being removed from the petri
dish.

Once the fry hatch, they are transferred into a larger container, but
remain in EM until they enter the water column.  Once swimming
(~10days), the fry are transferred to a Max Hatch facility, where they
remain for upto 2 months.

The only thing i could think with regards to the possibility of a toxin
in the water, would be if it was something passed down from the parents
like heavy metal build up, or something like that.

I have noticed that after the first day, anywhere from a few - 3/4 of
the embryos may have died, but i just remove them and replace the
water.  Do you think it would be more appropriate to completely replace
the petridish with a fresh one, and only transfer the live embryos?

many thanks,

leviathan


eas at stowers-institute.org wrote:
> Leviathan,
>
> You may be on the right track with respect to a toxin. I'm curious to
> know a bit more about your procedures and material choices for the
> storage of embryos and larvae, as some materials are quite toxic to
> embryos.
>
>
>
> Leviathan wrote:
> > Hi guys,
> >
> > i maintain a zebrafish facility in australia, for use in scientific
> > research at adelaide university.  I am still fairly new to the
> > facility.
> >
> > recently I have been having problems with a mutation appearing in my
> > offspring.  Originally i thought the mutation was specific to one
> > strain of fish (tuebingen), and began a program to out breed the
> > mutation until i am able to aquire a new source of the fish.  More
> > recently however, i have discovered the same phenotype in two
> > completely seperate strains of fish (WT and WIK).  This has made me
> > think that the phenotype i have been seeing may not be related to the
> > genetics of the individual fish lines, but rather to a toxin in the
> > water or something like that.
> >
> > to see a photo of the mutation click:
> > http://forum.fish.com/tm.asp?m=2236&mpage=1&key=&#2670
> >
> > The fish with the 'curly' phenotype, never develop a swim bladder, and
> > so are unable to enter the water column.  Which is handy for seperating
> > out the deformed fish.  The phenotype is exactly the same in all three
> > lines of fish.
> >
> > The occurence in the Tuebingen line of fish was about 1/4 of the
> > progeny, which is why i thought it was likely to be a recessive
> > mutation that had been amplified by inbreeding after a major population
> > bottleneck, but the fact that the penotype has now appeared in two
> > seperate strains of zf makes me think that it might be something else.
> > 
> > does anyone have any thoughts on my problem?



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