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Fwd: FW: Interesting Results Regarding Radioresistant Bacteria
I received this through another list server and
thought it might be of interest.
>
> >From: "Paul Blake"
> >Subject: [Navrhoret] Interesting Results From USUHS
> Research Regarding Radioresistant Bacteria
> >Date: Thu, 30 Sep 2004 15:40:20 -0400
> >
> >Colleagues:
> >
> >I thought you might find the attached article of
> interest. More details are
> >available at:
> >
> >http://www.usuhs.mil/pat/deinococcus/index_20.htm
> >
> >Very respectfully,
> >
> >CAPT Paul K. Blake, MSC, USN
> >Assistant Professor
> >Department of Radiology and Radiological Sciences
> >Uniformed Services University of the Health
> Sciences
> ATTACHMENT part 2 message/rfc822
> Date: Thu, 30 Sep 2004 14:39:18 -0400
> From: "Sharon Willis"
. . .
> Subject: USUHS Faculty in the News
>
> The following article just appeared on Nature.com
> and features Department of Pathology faculty member
> Dr. Michael Daly. The work of Dr. Daly and his team
> "Accumulation of Mn(II) in Deinococcus radiodurans
> Facilitates Gamma-Radiation Resistance" was
> published in the most recent edition of the journal
> Science.
>
> Sharon Willis
> Alumni Affairs
>
> Published online: 30 September 2004; |
> doi:10.1038/news040927-18 Secret of radiation-proof
> bugs proposed Helen Pearson
> Internal antioxidants may shield cells from
> radiation damage.
>
> US researchers have come up with a novel theory for
> how a tiny, tough bacterium can survive doses of
> radiation 2,000 times those that would fry a person.
> The unassuming red bacterium, called Deinococcus
> radiodurans, was discovered around 50 years ago in a
> batch of irradiated meat. Ever since, scientists
> have wondered how it can withstand radiation better
> than almost any other organism in the world.
> "They're better than cockroaches," says
> microbiologist James Imlay at the University of
> Illinois, Urbana.Researchers know that the bug is
> particularly good at patching up DNA damage wrought
> by radiation. Now Michael Daly of the Uniformed
> Services University of the Health Sciences in
> Bethesda, Maryland, and his team have come up with a
> possible explanation why. By comparing bacteria with
> different sensitivities to radiation, the team found
> that the most resistant bacteria tend to store up
> high levels of manganese and relatively low levels
> of iron. By contrast, the bacteria that shrivel up
> at a hint of radiation have little manganese and
> more iron. Artificially lowering the manganese
> levels also made bacteria more susceptible to
> radiation damage, the team reports report in
> Science1. "It was quite stunning to us," Daly
> says.The marvels of manganeseDaly suggests that the
> manganese helps to clear up damaging molecules, such
> as free radicals, that are released by the bugs'
> metabolism. This leaves the bacteria in a healthier
> state and better able to patch up DNA damaged by
> radiation. To test this theory, the team is now
> trying to create radiation-resistant strains of
> Escherichia coli by pumping up their levels of
> manganese.If manganese also proves protective in
> human cells, Daly foresees numerous uses. A dose of
> antioxidants that mimic some of the effects of
> manganese, such as vitamin E, might safeguard the
> cells of those who are exposed to radiation by a
> nuclear accident, for example. The discovery might
> also help those receiving radiation therapy for
> cancer, Daly speculates. A drug might be designed
> that boosts the amount of manganese in healthy
> cells, but leaves cancerous ones alone. This would
> render healthy tissue resistant to the radiation,
> and avoid some side-effects of the therapy. "There's
> some really important stuff here," Daly says.But
> Imlay cautions that such speculation is premature,
> because the radiation-resistant bacteria might have
> high manganese for another reason unconnected to
> their hardiness. The team needs to show exactly how
> manganese helps bacteria recover from radiation
> damage, he says.Before this, scientists have come up
> with other explanations for the robustness of the
> bacteria. Last year, a team of scientists proposed
> that peculiar circular rings of DNA in the bacteria
> help them patch up their damaged DNA2. But Daly grew
> bacteria in which these rings were missing and
> showed that they were just as hardy.
>
> References 1. Daly M., et al. Sciencexpress,
> doi:10.1126/science.1103185 (2004). 2. Levin-Zaidman
> S., Englander J., Shimoni E., Sharma A. K., Minton
> K. W. & Minsky A. Science, 299. 254 - 256 (2003). |
> Article | PubMed | ISI | ChemPort |
=====
+++++++++++++++++++
"A devotee of Truth may not do anything in deference to convention. He must always hold himself open to correction, and whenever he discovers himself to be wrong he must confess it at all costs and atone for it."
Monhandas K. Gandhi, in "Autobiography"
-- John
John Jacobus, MS
Certified Health Physicist
e-mail: crispy_bird@yahoo.com
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