Urgent:Radiation and mutation..

Wolf pianoman at mindless.com
Sun Oct 24 02:02:11 EST 1999


Thanks for the info....

well, I knew a couple of guys in the lab injected 59Fe into mice and
isolated the organs.
These organs have been stored in -80 freezer and they keep adding new
organs.
The way I found out about this was a few days ago I exposed my gel to the
film which was stored for 1 days on the top of this organs by accident.  The
film came out mostly dark.  First, I though some jerk exposed the film to
the light.
Today, I got my glycerol stocks from the freezer and isolated the plasmids.
Strangely, I could not digest DNA pieces with the enzymes which used to work
fine.
The strangth of Geiger reading is about 1-2 BMP.

But, I don't understand how DNA or molecules could be damaged by radiation
at -80 degree.

If this is the case, I have to throw out my whole glycerol stocks.

Thank you very much.
redflag wrote in message <381285A0.8A8AAC64 at videotron.ca>...
>Hi Wolf,
>
>59Fe is a beta(-) emitter with a period of 44.6 days. I have no
>information about its energy, but as the period is relatively short, this
>radionuclide probably has a strong activity.
>
>You says that radioactivity is sill very high. Have you got an idea of the
>level ? Did you get the radioactivity level with a Geiger-Muller meter ?
>Was the radioactive source inside the -80°C freezer ? Do you know its
>nature ? Is the source old or not ?
>
>Even without this information, I am pessimistic. If your stocks really
>have been exposed for more than 2 months, the DNA and others molecules has
>undoubtedly been damaged.
>Depending on the dose they received, cells might grow or not grow when put
>in culture. Double stranded  breaks (dsb) are lethal, when single strand
>breaks (ssb) can be repaired. Point mutations are mainly non-lethal.
>
>What you can do is extract a sample DNA from your irradiated stock and
>deposit it on gel for migration. PFGE would be better to see if the DNA is
>degradated. Many strips on your gel would mean that the DNA is fragmented,
>and thus there's nothing to do with, unless you want to study "hot points"
>of  induced mutations...
>
>You can also do a comet assay, which is a specific-damaged DNA
>measurement.
>You can get info about this assay at
>http://www-hotel.uu.se/occmed/forskning/scg/scg.html
>
>Hope this helps,
>
>Seb.
>
>Sébastien Charpentier, MSc, Radiation Biology.
>scharpen at videotron.ca
>
>Wolf a écrit :
>
>> Hello People...
>>
>> I don't think this is the proper site for posting but I think I might
>> get some answers for my question.
>>
>> I just find out that my E.Coli and yeast glycerol stocks have been
>> exposed to high radiation by 59Fe for more than  2 months.  The
>> radioactivity is still very very high.
>>
>> Is it possible to have any effects on my glycerol stock from radiation
>> such as mutation or whatever possible damage?
>>
>> Thank you very much for any comments.
>





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