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Re: [Killietalk] carbonates (probably)/my two cents
I wonder about two things:
1. I'm not sure that different proteins have even roughly the same affinities
for dyes like methylene blue or
acriflavine. I think it may be possible to essentially "fix" the chorion
proteins with too much dye. Methylene blue
used to be considered one of the"vital stains" that could be used on living
tissue. I have never read an
explanation for its bactericidal action (or is it just a fungicide?). I've
always assumed that because it can bind to
DNA (indeed, in can be a stain for both DNA and RNA on electrophoresis gels,
though it is not especially
sensitive) it tended to differentially limit the growth of organisms with a
high rate of DNA synthesis and cell
division, like bacteria. With acriflavine we are on perhaps firmer ground,
for the proflavins as a group are
intercalating dyes that can get between the paired bases of a DNA double helix
and distort it. Repair
mechanisms go to work which can then cause deletions and/or additions of
single bases, resulting in lethal
"frameshift" mutations. Although I've used large amounts of acriflavine in
the past, I would not now have iin
my fishroom. Please note, though, that much of the literature concerns
proflavin itself (a very powerful
mutagen) and that I can find nothing about acriflavine per se. My
generalization is based on chemical similarfity
and not on direct data. I know nothing of how the third major "fungicide" dye
we use, malachite green, acts
biologically. Some histologists that I knew considered it similar to methyl
green, a known general protein stain.
2. There is now a considerable literature on the hatching chorionase from
work with medaka, F. heterolclitus,
and some salmonids. I don't havge that literature here at my disposal, buyt i
think that some of the
investigators involved would be surprised at the hypothesis that CO2 levels
that trigger the hatching process
depend on exogenous bacteria. The "conventional wisdom" that I seem to have
derived from the literature
(perhaps incorrectly) is that increasing movements by the embryo and perhaps
increased metabolic rate
generate enough CO2 to induce the chorionase, or to release it from
intracellular storage vessicles (I can't
remember which).
>===== Original Message From
rgoldstein at rjgacarolina_com =====
>>>
>> High GH (8 or10+ degrees) seems to make eggs of rainforest species have
>> trouble hatching. It acts about like adding too much dye and the chorion
>> seems to get too tough to be broken down by the hatch enzymes. I have
>> never seen sound documentation of this, but it is common mythology that
>> seems to hold sorta true. IDK what effect it has on the ovaries, because
>> my fish simply won't let me fool with them.
>>
>
>First of all, shame on you for trying to fool with your fishes' ovaries
>:). But back to the dye interaction with chorions. The internal layers of
>the chorion are proteins subject to destruction by chorionase from the
>throats of the hatching fry. I don't know how dyes could affect these
>proteins and not the fry's other proteins, which would kill them. I think
>a more likely effect of too much dye (and I agree there can be too much)
>is that it prevents bacterial growth necesary to generate the carbon
>dioxide needed to stimulate the release of chorionase. No bacterial
>metabolism leads to no CO2 trigger, to no release of hatching enzyme, and
>no dissolution of the inner layers of the chorion. Like you, I have no
>evidence, but this is just a biologist's thought processes at work (a rare
>event in my case). - RJG
>
>
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