AW: [ RadSafe ] Bacterium can survive doses of ionising radiationthousands of times stronger than would kill a human

[Rainer.Facius at dlr.de]

>From WIKIPEDIA: "Michael Daly of the Uniformed Services University of the Health Sciences suggests that the bacterium uses manganese to protect itself against radiation damage."

John, 

thank you for this additional pointer. In the meantime Daly et al (2007) corroborated the above conjecture by showing that Mn protects the repair enzymes(!) from being degraded by high doses.

<quote>We present the case that protein, rather than DNA, is the principal target of the biological action of IR in sensitive bacteria, and extreme resistance in Mn-accumulating bacteria is based on protein protection. <endquote>


Once more you see the by now common place finding that - contrary to still most text-books and to the credo of LNT proponents - not the primary DNA damage determines the fate of the irradiated organism but the sophistications of its repair systems. Therefore I also thank Fred Dawson for his pointer which led me to the PLoS article.

Kind regards, Rainer 


Daly MJ, Gaidamakova EK, Matrosova VY, Vasilenko A, Zhai M, et al. Protein oxidation implicated as the primary determinant of bacterial radioresistance. PLoS Biol 5#4 (2007)e92.

Dr. Rainer Facius
German Aerospace Center
Institute of Aerospace Medicine
Linder Hoehe
51147 Koeln
GERMANY
Voice: +49 2203 601 3147 or 3150
FAX:   +49 2203 61970

 


________________________________

Von: radsafe-bounces at radlab.nl im Auftrag von John Jacobus
Gesendet: Fr 13.04.2007 18:59
An: Dawson, Fred Mr; radsafe at radlab.nl; srp-uk at yahoogroups.com
Betreff: Re: [ RadSafe ] Bacterium can survive doses of ionising radiationthousands of times stronger than would kill a human



Fred,
I would look at
http://en.wikipedia.org/wiki/Deinococcus_radiodurans

Many "simple" organsims have mechanism to withstand
the effects of toxins, radiation, salinity, pH, etc.
There are probably more that resist ionizing radiation
that have not been identified.

It is interesting to note that Deinococcus radiodurans
was identified in the 1950s.  Yet, everytime it is
mentioned it is like a new discovery.

--- "Dawson, Fred Mr" <Fred.Dawson199 at mod.uk> wrote:

> New Scientist reports:-
>
> Nicknamed Conan the Bacterium, Deinococcus
> radiodurans can survive doses
> of ionising radiation thousands of times stronger
> than would kill a
> human. So how does it do it?
>
http://www.newscientist.com/article/dn11447-tough-bug-reveals-key-to-rad
> iation-resistance.html
>
> Fred Dawson
> Fwp_dawson at hotmail.com