Autoradiography: "Hole in the middle of Southern Bands"
Johan de Boer
jdboer at SOL.UVIC.CA
Fri Sep 10 14:02:26 EST 1993
> This was recently posted to bionet.molbio.methds-reagnts:
> + Here's a weird problem: recently we have started seeing empty centers to
> +intense bands in our PCR-Southerns (amplify, blot, probe with internal
> +fragment, autorad). Previous months of blotting never showed this. Now
> +past 2 weeks, several blots have it. Sometimes only in certain lanes of a
> +single blot, sometimes all. Sometimes appears as a clear area in the lane
> +(2 sides of band are hot), other times it's a "doughnut".
> I'm convinced (as at least one other poster was) that this was actually an
> autoradiographic/photographic effect. That is, the Xray film used is
> normally turned black from exposure to 32P betatron emissions (after the
> film is developed.) But in cases where there is a very hot "band" it can
> actually disappear off the film -- or even be a clear band in grey or
> black background.
> So I'm cross-posting this to sci.chem in the hopes of getting the details
> of the photochemical reactions going on here. Presumably a certain amount
> of energy causes the silver salts in the film to convert to a non-soluble,
> black form, but above a certain amount of energy the non-soluble products
> convert again into some (new?) soluble form.
Isn't that called solarization?
Johan de boer
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