Radioactivity muddles the alphabet of DNA

[kristopher]

"The natural radioactivity in focus involved the decay of carbon atoms, Carbon-14, turning into nitrogen atoms, Nitrogen-14"

Radioactivity muddles the alphabet of DNA

Using high-performance computers, the research team from Curtin and Los Alamos National Laboratory were able to show radioactivity could alter molecular structures which encode genetic information, creating new molecules that do not belong to the four-letter alphabet of DNA.
Professor Nigel Marks from Curtin's Discipline of Physics and Astronomy and Curtin's Nanochemistry Research Institute said the new molecules may well generate mutations by confusing the replication mechanisms in DNA.
"This work takes an entirely new direction on research into natural radioactivity in biology and raises important questions about genetic mutation," Professor Marks said.
"We have discovered a subtle process that could easily be overlooked by the standard cell repair mechanisms in the body, potentially creating a new pathway for mutations to occur."
Professor Marks said the work was both exciting and unexpected, emerging as a spin-off from an Australian Research Council funded project on nuclear waste.


Read more at: http://phys.org/news/2013-12-radioactivity-alphabet-dna.html#jCp

[PamW]

1. Yes; this has been hypothesized for some time...

Yes; this has been hypothesized for some time.

And what if you discover that NATURAL radioactivity, such as that studied involving Carbon-14 decaying to Nitrogen-14

Are you going to somehow ban Carbon-14? Good luck with that; because Mother Nature makes OODLES of it all the time due to the solar radiation interacting with the atmosphere.

Additionally, the radiation given off in Carbon-14 decay is beta-minus particles; which are simply electrons!.

You going to ban electrons?

This is very interesting work; because it increases our understanding of such mechanisms.

However, there is NOTHING here of a sinister nature that we found out here that radiation or radioactivity is even more dangerous than we thought.

Quite the contrary; these mutations were with NATURAL radioactivity; so much for the anti-nuke's excuse that natural radiation is OK, because it is "natural".

"Natural" radiation is every bit as "bad" as the man-made stuff; but there's a LOT more of it.

For example, when we compare the amount of natural radiation to how much is man-made:

http://www.umich.edu/~radinfo/introduction/radrus.htm

We see that radiation from nuclear power ( "nuclear fuel cycle" in table ) is 3000 TIMES LESS than natural radiation.

We see that radiation from nuclear weapons testing ( "fallout" in table ) is 3000 TIMES LESS than natural radiation.

As much as the typical anti-nuke goes around screaming about Fukushima; we see from the following article by Professor Richard Muller of the University of California at Berkeley Physic Department, that the NATURAL radiation in Denver is THREE TIMES the contamination of Fukushima:

http://online.wsj.com/news/articles/SB10000872396390444772404577589270444059332

The real lesson should be that people should QUIT being so PHOBIC about radiation.

It is all around us; just like germs. Germs are all around us, and can give us debilitating and deadly diseases if not for our immune systems. It's these every day germs that actually kill the AIDS victim; not the HIV virus itself. HIV just destroys the immune system. The everyday germs do the rest.

The phobia that some have over radiation resembles the phobia that some people have about germs. It's called "OCD" and Howard Hughes was probably the most famous person afflicted with it. However, there is treatment.

So if someone finds themselves very radiation phobic; the best course of action is not to protest nuclear power; but go see a psychiatrist, because you may have a mental illness.

The good thing about science is that it is true, whether or not you believe in it.
--Neil deGrasse Tyson

PamW

[kristopher]

2. That's an interesting take on the new data...

Last edited Wed Dec 18, 2013, 12:18 PM - Edit history (1)

The article:

""This work takes an entirely new direction on research into natural radioactivity in biology and raises important questions about genetic mutation," Professor Marks said."

and

"Professor Marks said the work was both exciting and unexpected, emerging as a spin-off from an Australian Research Council funded project on nuclear waste."

PamGreg:

"Yes; this has been hypothesized for some time."

The article is discussing the naturally occurring carbon14 in all living organisms.

PamGreg writes:

Are you going to somehow ban Carbon-14? Good luck with that; because Mother Nature makes OODLES of it all the time due to the solar radiation interacting with the atmosphere.

There's no need to continue any further.

The reason I posted this in EE rather than the Science forum was that I'm wondering if these findings are going to be relevant to recent research on the effectiveness of cell repair mechanisms; research, I should add, that the nuclear industry delights in misusing by claiming it as "proof" invalidating the Linear No Threshold approach to understanding the risks of damage from ionizing radiation.
Even though it isn't dealing with ionizing radiation, this statement from the researcher piqued my curiosity.

"We have discovered a subtle process that could easily be overlooked by the standard cell repair mechanisms in the body, potentially creating a new pathway for mutations to occur."

[PamW]

3. Evidently you don't understand LINEARITY!!

kristopher states
I should add, that the nuclear industry delights in misusing by claiming it as "proof" invalidating the Linear No Threshold approach to understanding the risks of damage from ionizing radiation.

The existence of a repair mechanism DOES INVALIDATE Linearity.

If you don't know that; then you don't understand what is meant by "Linearity".

The initial damage IS proportional to the radiation dose. If that were ALL that was happening, then there would be linearity.

But if there is a repair mechanism; then the additional effect of the repair mechanism DEVIATES from the initial linearity.

It's as if we have a linear equation: y = ax

If I add an exponential term to it; y = ax + exp(cx)

then BY DEFINITION I've messed up linearity.

Sorry; but the experimentally demonstrated existence of a repair mechanism CONCLUSIVELY and BY DEFINITION invalidate linearity.

PamW

[darkangel218]

5. Pam, ffs

Why are you always so condescending??

Start your own "nuke praise " thread , rather then putting people down constantly. You called us "elementary school children who don't want to learn" in the other thread. Wtf??
Try to respect that not everyone agrees with you.

[PamW]

6. I CALL them as I SEE them!!!

darkangel,

It's simple. I call them as I see them.

You've got me all wrong. I DO respect people with well considered opinions that disagree with me. Not everyone can agree.

However, if someone has a well thought out opinion that is different from my own; they are welcome to that.

What I do NOT respect are the opinions of IDIOTS .

I do NOT respect the opinions of people whose mental process in forming those opinions would embarrass an elementary school child.

It's a corollary to the old adage, "You have a right to your own opinions, but NOT your own facts".

When I see childishly ignorant opinions because they were based on someone's "own facts" that are NOT true; then I have ABSOLUTELY ZERO respect for such boneheads.

Why should anyone respect "opinions" where an empty mind was just opened and a bunch of propaganda poured in?

That is so antithetical to the ways of scientists.

PamW

[darkangel218]

7. So Im an idiot because i oppose nuclear power??

I fucking lived through Chernobyl!!! I was a few hundred kilometers away!!! People died, and many more will die, due to that disaster.

It sickens me to my stomach to see how you promote nuke energy. You think you know it all, but you have no idea of the horror of a nuclear plant accident.

[PamW]

9. NOT at ALL!!!

NO - I did NOT say that.

You can have your own opinion of nuclear power that is different than mine.

Go back and read what I said. I didn't say that people were idiots for opposing nuclear power.

That's NOT the determining factor.

It's explained quite clearly in the above post. The determining factor is how well-reasoned someone's opinion is.

If you have a different opinion; that is based on good solid facts and your own experience; you are most certainly welcome to your opinion.

I can very well understand how living through the consequences of the Chernobyl accident could affect how one views nuclear power, and how one "weights" the various factors in arriving at an overall conclusion.

What I object to are people who don't do their own homework, they go to some "advocacy" website, one with an "axe to grind", and they just accept everything posted on the website as if it were handed down from the Almighty on stone tablets.

Armed with such "facts"; they then go forth as good little automatons and spread the propaganda of the website.

If that doesn't sound like what you are doing; and I don't believe it does; then I do NOT count you in the group of gullible idiots.

I think you are reading more into what I wrote than what I intended.

Actually, I DO know a lot about nuclear accidents. However, I have the advantage of being a trained scientist and I'm not affected by the "fear mongers" that exaggerate the accident.

PamW

[darkangel218]

11. I'm sorry, but you're contradicting yourself.

Which fear monger am I bowing to? Do you think my attitude against nuclear plants is solely based on my experience , and zero to do with actual facts???

Perhaps if you will stop referring to anyone who disagrees with you as "elementary school children" who need to be " taught" , then maybe we could have a conversation.

[kristopher]

8. That is the claim of the nuclear industry.

But the argument certainly isn't accepted by the broader scientific community not even the authors of the study themselves.

[PamW]

10. Certainly the argument about what IS / IS NOT LINEAR...

kristopher,

I believe you don't understand that the agreement on "linearity" is unanimous.

A "linear" model is a very specific, very limited, and very idealized model.

There's very few things that are truly linear; and anything as complex as the human response to radiation damage is not something one would even remotely expect as being something that was so trivially simple as being "linear".

PamW

[kristopher]

12. LNT theory is accepted by by everyone except those promoting the nuclear industry.

Even the authors of the study that you cite do not consider their work a refutation of the LNT theory.

[PamW]

13. NOOO...!!!

Last edited Wed Dec 18, 2013, 08:42 PM - Edit history (1)

kristopher,

LNT is accepted as a conservative overprediction that can be used for drafting things like regulations.

I don't know of ANY legitimate scientist in the medical radiation field that accepts LNT as an accurate model of what biological tissues ACTUALLY do.

The LNT model is an approximation and an approximation that will always OVER PREDICT the effect.

Therefore, it is useful in writing things like regulations; because it is conservative because it always over predicts.

Therefore, if you make a regulation that says someone can get no more than 10 mSv when calculated by the LNT model; then you know that the ACTUAL dose / radiation damage will be LESS than 10 mSV.

After all THINK about it. The original post of the thread is how scientists used the new supercomputers at Los Alamos to calculate all the physics that goes into determining the amount of biological damage. Then someone says that an EXACT SOLUTION is given by:

y = a*x

Give me a break!! The LNT model is a MODEL; nothing more.

The biological damage done by radiation involves extremely complex chemistry and physics; hence the use of the supercomputer.

It is NOT going to EXACTLY equal the result that comes from:

y = a*x

LNT is a MODEL and NOT reality.

PamW

[kristopher]

14. Yeeees!

Your blather notwithstanding.

[PamW]

15. Credentials??????

kristopher,

Have you been hiding more credentials in the sciences from us???

You studied radiation biology and obtained a degree in same from WHERE again????

PamW

[kristopher]

16. ROFLMAO

As has been pointed out to you before, the only credential required is the ability to read.
And that being the case it is glaringly obvious from your constant misapplication of information alongside an endless cascade of boneheaded blunders of comprehension, that most 7th grade drop-outs are more qualified in that area than you.

http://www.democraticunderground.com/112760174#post4
http://www.democraticunderground.com/112760174#post11
http://www.democraticunderground.com/112760174#post15
http://www.democraticunderground.com/112760174#post22
http://www.democraticunderground.com/112760174#post29

[madokie]

17. Kinda sucks the oxygen right out of the room huh

If pW don't know it it ain't worth knowing. I don't say that lightly either.

When do we get our degrees is what I want to know. Hell I'm afraid to ask her for the beat down I'd surely get.

this pw shit is not what the ee group is supposed to be about but somehow thats what its turned into.

[caraher]

18. That's pretty much the mission of a disruptor

If you're not getting entertainment value out of those posts the best move is to use the ignore list

[PamW]

21. BALONEY!!!

kristopher states
As has been pointed out to you before, the only credential required is the ability to read.

Of COURSE more is needed than just the ability to read.

One has to have the ability to analyze and understand what is being read.

Otherwise, it is just an empty mind with someone else's "facts" which may not even be true; poured in.

That's not a formula for intelligent discourse.

It's only a formula for being a "sheeple"; and a little automaton that thinks / behaves just as its propagandist master dictates.

PamW

[caraher]

19. The sad thing is that there is an actual intelligent scientific debate to be had about LNT

You'd think the handlers for the guest who likes to use "greenie" as an insult would offer much better arguments than this "Is not/Is too" stuff focused on the meaning of "linearity." I could supply some myself, but I'm much more entertained by waiting to see whether the research team eventually feeds them to the keyboard warrior.

The OP is about an interesting piece of computational chemistry. I wouldn't get overly excited about claims to groundbreaking novelty in a university press release announcing the paper (which is the real source for the article). We know there are damage mechanisms and repair mechanisms, but the LNT issue is less about identifying the exact details of one such mechanism (or even whether they've identified a particular kind of damage that might be harder to identify and fix) than about how all the mechanisms interact in a specific dose rate range.

The LNT hypothesis may be wrong. It has also formed the basis for decades of radiation protection policy as a conservative way to manage uncertainty about low-dose radiation effects, and has long guided the engineering practice in the nuclear industry. It's certainly not something dreamed up by anti-nuclear voices to drum up irrational fear of radiation.

[kristopher]

20. "how all the mechanisms interact in a specific dose rate range"

That makes sense and leads to the question I saw when reading the story. The efficiency of the cell repair mechanism IIRC was established reasonably well and the results produced an anomaly that was looking for an explanation. I'd be curious about whether this would explain the discrepancy between that observed rate of repair and the presence of statistical support for observed rates of cancer at low doses?
I wouldn't expect the answer to be part of the research reported on, but does it lay the groundwork for a more discerning look at specific low dose triggers? Would you expect they will be able to suss out the data for those individual pathways that are, as you say, interacting to produce the LNT guidelines?

[caraher]

22. I think there are two somewhat parallel lines of research here

The research in your OP is atomic-level computational work, and can be handy for identifying specific pathways for DNA change/damage. What's interesting about this study is its role as a sort of "existence proof" - that it is possible for damage to take a form not really considered before.

This would be potentially useful in guiding lab research on what happens on a cellular level, which would have implications for our understanding of why the dose response might be expected to take a particular form (whether the response is linear or not).

The particular C-14 decay mechanism they looked at probably doesn't translate well to radiation damage from things like nuclear waste because as I understand it, their concern is chiefly with the effects of a carbon atom transmuting into nitrogen within DNA (as opposed to the effect of a cell absorbing energy from a source external to the DNA). My understanding of the usual radiation damage pathway is that ionizing radiation creates free radicals, and the subsequent interaction of the free radicals with DNA causes most of the trouble. I think this is part of the claim to novelty in this research - it concerns effects of radioactive decay that originates in the DNA molecule itself. But it might be a great probe of what does and does not trigger repair mechanisms.

With respect to using LNT in radiation protection, I think what makes the whole issue complicated is that LNT is not based on ab initio chemistry and cell biology, but on epidemiology. Obviously one cannot ethically or even pragmatically do systematic controlled human studies of dose response so we're limited to trying to glean information from historical examples of mass exposure events. Except for a few cancers with obvious links to particular contaminants (e.g. I-131 and thyroid cancer), the "signal" is very hard to dig out of the high background cancer rate, which is why even the Chernobyl cancer death rate estimated by conventional LNT figures produces numbers that are hard to fish out of noise. The value of computational, in vitro and animal studies of radiation effects is that they might provide a sound theoretical basis for expected low-dose effects.

The last Biological Effects of Ionizing Radiation report, BEIR VII, came out in support of continued use of LNT:

Despite the challenges associated with understanding the health effects of low doses of low-LET radiation, current knowledge allows several conclusions. The BEIR VII committee concludes that current scientific evidence is consistent with the hypothesis that there is a linear dose-response relationship between exposure to ionizing radiation and the development of radiation-induced solid cancers in humans. The committee further judges it unlikely that a threshold exists for the induction of cancers but notes that the occurrence of radiation-induced cancers at low doses will be small. The committee maintains that other health effects (such as heart disease and stroke) occur at high radiation doses, but additional data must be gathered before an assessment can be made of any possible connection between low doses of radiation and noncancer health effects. Additionally, the committee concludes that although adverse health effects in children of exposed parents (attributable to radiation-induced mutations) have not been found, there are extensive data on radiation-induced transmissible mutations in mice and other organisms. Thus, there is no reason to believe that humans would be immune to this sort of harm.

The debate is ongoing. A medical physicist friend of mine who has studied this more than I have is quite convinced that a threshold model is more plausible (and he now works in ultrasound, so it's immaterial to his bread-and-butter). A good example of this line of argument is the unambiguously-titled editorial, "The Linear No-Threshold Relationship Is Inconsistent with Radiation Biologic and Experimental Data", which was published with a less-noted rebuttal, "Risks Associated with Low Doses and Low Dose Rates of Ionizing Radiation: Why Linearity May Be (Almost) the Best We Can Do."

[PamW]

23. EXACTLY what I was saying above...

caraher,

Your link above from the National Institutes of Health says precisely what I was saying above:

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2663584/

The LNT model was introduced as a concept to facilitate radiation protection (7). But the use of this model led to the claim that even the smallest dose (one electron traversing a cell) may initiate carcinogenesis—for instance, from diagnostic x-ray sources (8,9). This claim is highly hypothetical and has resulted in medical, economic, and other societal harm.

The French Academies report (10) concluded that the LNT model and its use for assessing the risks associated with low doses are not based on scientific evidence.

Thank you for the link.

PamW