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Prions Observed Jumping Species Barrier
Posted by
timothy
on Sun Sep 07, 2008 08:40 PM
from the only-applies-if-you-have-brain-tissue dept.
from the only-applies-if-you-have-brain-tissue dept.
palegray.net writes "Nature is reporting on new findings that prions jump species barriers. Believed to be responsible for ailments such as Creutzfeld-Jakob disease and 'mad cow' disease, prions are thought to disrupt biological processes by causing normal proteins to fold abnormally. Researchers at the University of Texas Medical Branch in Galveston have observed infectious prions from hamsters causing abnormal protein development in mice, along with a range of other observations on prion actions in test tube environments. From the article: '... they also found that when a prion jumps species, it produces a new kind of prion. "This is very worrisome," says Claudio Soto, who led the research, published in Cell. "The universe of possible prions could be much larger than we thought."' Sounds like another good reason to donate your spare CPU cycles to projects like Folding@home."
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Your Rights Online: Appeals Court Rules US Can Block Mad Cow Testing 455 comments
fahrbot-bot tips a story of mad cow disease, a private meat packer that wants to test all of its beef for the disease, and the USDA, which controls access to the test kits and just won an appeals court ruling that the government has the authority to block testing above and beyond the 1% the agency performs. Creekstone Farms Premium Beef sought to test 100% of its beef, in order to reassure its export markets, especially Japan and South Korea, that its beef is safe. Large meat packers opposed any such private testing, because they feared they would be forced into 100% testing and would have to raise prices. The appeals court ruled, 2 to 1, that under a 1913 law, test kits that are used only after an animal is killed still constitute "diagnosis" and "treatment" — this for a disease that has no treatment and is 100% fatal — and therefore fall under the USDA's authority to regulate.
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Corrected article link (Score:5, Informative)
Those with subscriptions to Cell can also get the full text [cell.com], Full Text in PDF [cell.com], and the Supplementary Data [cell.com].
Re: (Score:2)
The bigger story (Score:2, Funny)
Nature is reporting on new findings that prions jump species barriers
It's confirmed. Our planet (i.e. Nature) is sentient and into science journalism!
Oh No! (Score:2, Funny)
Help feed a hungry test tube. (Score:2, Funny)
"The universe of possible prions could be much larger than we thought."' Sounds like another good reason to donate your spare CPU cycles to projects like Folding@home."
Can I donate my spare prions instead?
While troubling, also cool. (Score:5, Insightful)
It seems like any sufficiently complex system(biological proteins in this case), is at considerable risk of having something analogous to life spring up and cause trouble.
Re:While troubling, also cool. (Score:5, Interesting)
Parent
Re:While troubling, also cool. (Score:5, Interesting)
Have you heard of Cairn's-Smith's clay theory of abiogenesis
http://en.wikipedia.org/wiki/Graham_Cairns-Smith#Clay_theory [wikipedia.org]
In simplified form, clay theory runs as follows: Clays form naturally from silicates in solution. Clay crystals, as other crystals, preserve their external formal arrangement as they grow, snap and grow further. Masses of clay crystals of a particular external form may happen to affect their environment in ways which affect their chances of further replication â" for example, a 'stickier' clay crystal is more likely to silt a stream bed, creating an environment conducive to further sedimentation. It is conceivable that such effects could extend to the creation of flat areas likely to be exposed to air, dry and turn to wind-borne dust, which could fall at random in other streams. Thus by simple, inorganic, physical processes, a selection environment might exist for the reproduction of clay crystals of the 'stickier' shape.
There follows a process of natural selection for clay crystals which trap certain forms of molecules to their surfaces (those which enhance their replication potential). Quite complex proto-organic molecules can be catalysed by the surface properties of silicates. The final step occurs when these complex molecules perform a 'Genetic Takeover' from their clay 'vehicle', becoming an independent locus of replication - an evolutionary moment that might be understood as the first exaptation.
Richard Dawkins said of this that he doesn't believe this particular theory of abiogenesis but something like this must have happened.
He memorably said that one day a robot equivalent of Cairns Smith may note wryly that silicon based machines like him eventually took over from carbon based life like us that built them as tools in the same way that carbon based replicators took over from silicon based clay lifeforms that built them as tools.
Parent
Re:While troubling, also cool. (Score:5, Informative)
These prions are single molecules that have a harmful effect on the host. I believe the word 'toxin' is a better description.
Prions don't self replicate, it's a substance that catalyzes (speeds up) the reaction of refolding an existing protein into another shape, not the formation of a protein out of other substances. If it catalyzed a different kind of reaction, you'd call it a toxic enzyme, not something on the continuum of life.
Parent
Re: (Score:3, Insightful)
That's the best description I've heard so far. Bad prions are a particulary nasty biological toxin because they can survive conditions that destroy other biological toxins. They can apparantly pass through digestion repeatedly, aren't destroyed by an ordinary autoclave, and survive for a long time exposed to sun and oxygen. It's apparantly hard to sterilize medical equipment in such a way that prions are destroyed.
The good news is that prion-based diseases are vanishingly rare. Avoid cannibalism and you
Re: (Score:3, Insightful)
The good news is that prion-based diseases are vanishingly rare. Avoid cannibalism and you're safe: so far meteor strikes are about as dangerous a threat, along with heart-attack induced by the stress of winning the lottery.
Don't overestimate the threat of meteor strikes. While there have been a lot of near misses and property damage, there are apparently no recorded instances of somebody being killed by a meteorite since 1929.
Just so you know.
Re:While troubling, also cool. (Score:5, Informative)
You're mistaken. Prions self-replicate by inducing other proteins to fold into prions like themselves. Prions thereby replicate and increase their numbers exponentially until they damage the organism. When symptoms appear, this process of exponential growth is already 95% complete and the organism will soon be dead. At that point, the organism is much more infectious because the number of prions is far higher than originally.
Because prions replicate themselves, they bio-accumulate over time. Since organisms can "inherit" the prions of other organisms by ingesting them, the prions can accumulate across generations. Which means that you can feed cows to other cows continuously, and the number of prions in the cow population will increase over generations. It may take several generations of cow cannibalism before disease will become apparent.
The prion hypothesis was interesting precisely because it proposed a mechanism of replication and infectivity which was not based upon DNA or RNA.
Parent
Re:While troubling, also cool. (Score:5, Funny)
Your name is not "Murphy" by any chance?
Parent
Why is this news again? (Score:3, Insightful)
So prions can make proteins into prions in other species, e.a. cross the species barrier? Big deal. We knew this in the nineties when the whole mad-cow disease was all over the news.
I'm sure it has some scientific significance, but I think the real question is how (ingested) prions reach the central nervous system, where the damage is done. And why it takes so long or doesn't happen at all in most cases.
Now that would shed some light on the amount of risk that eating a possibli infected piece of meat would pose. That would be news.
Re: (Score:3, Interesting)
i may have read the article wrong, but i'll give this a shot.
you're right that we know that prions from cows can cause problems in humans. but i think what the article said is that it creates a new kind of prion as well. so where there used to be just one mis-folded protein messing with you, now there are two mis-folded proteins messing with you, and each is mis-folded in a different way and can do a different thing to you. so while you used to just have apples, now you have apples and oranges to deal with.
Folding a bit too close to home (Score:2)
I guess prions take the Folding@Home idea a bit too literally.
The science of fear. (Score:2, Interesting)
I work for one of Claudio Soto's former PhD students. From my brief skimming of this paper, it seems to be a simple proof-of-concept transmission between mice and hampsters. The discussion section, like a lot of science, is pure speculation - logical, but no need for slashdotters to scream "OMG we're all going to die!"
I'm an avid MN deer hunter (and consumer...) and I've done a significant amount of work with PrP infected mice. While not worried about going crazy and having my brain melt in 15 years, I h
Ailment? (Score:5, Informative)
I'm sorry, but Creutzfeld-Jakob disease is a bit more than an "ailment." It's deadly and incurable. I think a slightly stronger word would be in order.
Prof. X got a name for them (Score:4, Funny)
"This process is slow, and normally taking thousands and thousands of years. But every few hundred millennia, evolution leaps forward."
"We called them, X-Prions"
Been known for quit some time (Score:5, Interesting)
I couple of years back, I did a lot of reading on Mad Cow. There were so many examples of it jumping the species barrier...and some of them many, many years old.
Here is an example from 18 years ago:
-=-=-=
http://www.highbeam.com/doc/1G1-111779850.html [highbeam.com]
WASHINGTON -- Eighteen years before last week's first confirmed case of mad cow disease in the United States, investigators concluded that an epidemic of a brain-wasting disease on a Wisconsin mink farm was probably caused by a malady similar to mad cow disease.
The Wisconsin farmer had fed his mink a steady supply of "downer" cows -- too sick or injured to move on their own -- like the one that tested positive for mad cow disease in Washington state last week. On Tuesday, the Department of Agriculture banned such animals for human consumption.
Long before the USDA action, the mink industry began discouraging farmers ..
-=-=-=
It is basically that anyone who did a little study would know that it could jump the species barrier...but it just can't do that until some people in white coats tell us it can do that...then it can.
transporter_ii
Re:Been known for quit some time (Score:5, Interesting)
Parent
Re:Been known for quit some time (Score:4, Insightful)
Uhuh. The summary is just wrong, is what's going on here. If you read the article, what it's actually about is a new way to study prions in vitro and test them to determine whether there's a possibility of them crossing a particular species barrier.
Which is, when you think about it, a very useful test to have available.
Parent
Scary (Score:5, Interesting)
It made me wonder, if it changes when it jumps species, maybe prion diseases are something new, so I did some quick checking on Wikipedia. I didn't track down more stuff yet, but I plan on following up. I didn't realize this, but it appears that a lot of prion diseases are fairly recent developments. Scrapie showed up in 1732, Bovine Spongiform Encephalopathy in the 1800s, CJD showed up around 1920, Kuru in 1957, Chronic Wasting Disease in 1967, Feline Spongiform Enecephalopathy 1990.
And these are more than half of the diseases caused by prions, I believe. That's more than a bit disconcerting.
Re:Scary (Score:5, Insightful)
I didn't realize this, but it appears that a lot of prion diseases are fairly recent developments.
People didn't eat as much meat as they do today, didn't live as long, and they certainly didn't feed their livestock with slaughterhouse waste. The latter is what got prions into the food chain in significant amounts.
Parent
Mark Purdey's alternative hypothesis (Score:5, Interesting)
... Mark Purdey [markpurdey.com] was, of course, the British beef farmer who had a different theory about Mad Cow. In the 80's the British government required all cattle to be dosed with an Organo-phostate pesticide, to combat a warble fly epidemic (these bugs punch holes in cattle skin, making the hides less suitable for leather seats).
Purdey was an organic farmer, and sued to protect his right to keep synthetic pesticides away from his herd. He won. A few years later Chernobyl went off, and some time after that the first Mad Cow epidemic occured. Purdey's cows were mostly immune. He had a few mad cows, but these were mostly transplants to his herd which had, presumably, been dosed with the pestacide.
As the years went by, Purdey turned into a scientist himself, doing the research that the british government wouldn't do because of their potential liability in having caused the mad-cow epidemic (by require farmers to poison their herds).
Basically, the pesticide used chellated (removed) copper from the treated body. Somehow manganese substitutes for copper, but it isn't a good subsitute. The radioactive fallout from Chernobyl didn't help things either. It's been years since I first read Purdey's site, so I don't remember the details.
He commented that the Mad Cow in Washington (the northwest state) came from a copper-deficient pasture in Canada, into an area where quite a bit of nuclear weapons research had been done in decades past. The mad deer in Colorado also occupy a site with extensive radiologic environmental poisoning.
So basically, Purdey's theory is that prions are an effect of environmental poisoning, not the cause of Mad-Cow-esque disease.
Purdey is deceased now (brain cancer?), but his site's still live. Definitely recommended reading.
Re:Mark Purdey's alternative hypothesis (Score:4, Insightful)
Parent
Re:Mark Purdey's alternative hypothesis (Score:5, Interesting)
Yes, but now I'm wondering... DNA can be damaged/mutated by environmental factors; proteins can be damaged by chemicals (when I was in college, we used the crude method of boiling proteins in a saturated lye solution to break them down into their various amino acids); why should prions be immune?
Which says nothing pro or con re this Purdey fellow's theory of the origin of BSE; he could be dead-wrong on that, yet correct as applied elsewhere. Or he may be completely off-base in every way, yet we should still look at *what* causes prions to "fold wrong"; who knows what we'll learn?
Parent
Re:Mark Purdey's alternative hypothesis (Score:4, Interesting)
Purdey's theory is that prions are an effect of environmental poisoning, not the cause of Mad-Cow-esque disease.
First off, those two statements are unrelated. Prions can cause TSEs regardless of if copper or manganese from the environment causes them. Secondly, it is pretty well accepted by the scientific community that prions are the cause of TSEs. You can infect animals with PrP-Sc (the misfolded form of the prion protein (PrP-C being the normally folded version) and cause TSE. If you knock out the PrP protein, mice are not susceptible to PrP-Sc.
What causes the first misfolding of PrP-C to PrP-Sc is unknown (unfortunately), and it is clear that PrP-C has copper-binding repeats, so an effect of Cu on the protein is a very likely possibility.
-Ted
Parent
Is that surprising ? (Score:3, Interesting)
Folding for Someone Else's Pocket (Score:5, Insightful)
Sounds like another good reason to donate your spare CPU cycles to projects like Folding@home."
So the public is donating a lot of computing time and electrical energy. What does the public get back?
If Folding@Home goes towards lining the pockets of a university endowment or a drug company's coffers, count me out. If the research product is required to be free from patents, and available for public good...full speed ahead. Somehow, I seriously doubt that any successful results will be freely available.
Re:Folding for Someone Else's Pocket (Score:5, Informative)
So the public is donating a lot of computing time and electrical energy. What does the public get back?
If Folding@Home goes towards lining the pockets of a university endowment or a drug company's coffers, count me out. If the research product is required to be free from patents, and available for public good...full speed ahead. Somehow, I seriously doubt that any successful results will be freely available.
The project is run by a non-profit company. Results are routinely made public. I don't see any reason to be concerned here.
Parent
idle cpu? (Score:4, Insightful)
There is not such a thing as "spare CPU cycles" since when you run a *@home program, CPU power consumption pikes.
In a laptop, when running any CPU intensive distributed program, battery level is stuck since all the power goes to the CPU instead of charging the battery.
Re: (Score:3, Funny)
Re:Folding@Home (Score:5, Insightful)
Instead of donating energy to run Folding on your inefficient PC, where the results have to be triple-checked - consider just donating money directly to the project instead of via your power bill.
Runtime on a trusted supercomputer / local cluster is going to be an order of magnitude more efficient in terms of data crunched per watt-hour.
Parent
Re: (Score:2)
That's a good point, I've never thought about that route before.
Re:Folding@Home (Score:5, Insightful)
Parent
Rosetta @ home (Score:5, Informative)
For this issue Rosetta at home (Boinc) might be a better choice for protein structure. It's already wokring on the prion problem.
Parent
Re:Folding@Home (Score:5, Informative)
>Runtime on a trusted supercomputer / local cluster is going to be an order of magnitude more efficient in terms of data crunched per watt-hour.
Problem is, there ain't no such thing on this planet.
From Wikipedia: http://en.wikipedia.org/wiki/Folding@home [wikipedia.org]
"On September 16, 2007, the Folding@home project officially attained a performance level higher than one petaFLOPS, becoming the first computing system of any kind to do so, although it had briefly peaked above one petaFLOPS in March 2007.[14][15]. In comparison, the fastest supercomputer in the world (as of June 2008, IBM's Roadrunner) peaks at 1.026 petaFLOPS[16]. In early May 2008 the project attained a sustained performance level higher than two petaFLOPS, again being the first computing system of any kind to do so. Now Folding@home computing cluster operates at above 2 petaFLOPS at all times, with a large majority of the performance coming from PlayStation 3 and GPU clients.[2] On August 20, 2008, the Folding@home project broke the three petaFLOPS milestone, once again being the first computing project of any kind in history to ever do so.[2]"
Parent
Re:Folding@Home (Score:4, Insightful)
Parent
Re:Folding@Home (Score:5, Informative)
Depends on when you run it. Coal plants burn more coal at night than they need for electricity to keep the furnaces hot for peak usage periods. If you run F@H between 9PM and 6AM, you're actually not having much impact on fossil fuel use, pollution or carbon footprint.
That's why electric utilities and some companies [google.org] are developing programs to make the best use of off-peak power. Electric cars, for example, are exciting because they could engage timers that charge them only during off-peak [greencarcongress.com].
F@H could do the same in principle, with a check-box to run only during late hours. I don't know if they have that feature now.
Parent
Re: (Score:2, Insightful)
It's like every /. article is an opportunity to espouse the same posts in a previous article. Let me save all the future posters their breathe...
Dirty energy is bad.
Global Warming.
Creationists are dumb.
DMCA is stoopid.
OMG zero day is here!
There, someone e-mail me when there's a comment worth reading.
Re:Folding@Home (Score:4, Funny)
Your email isn't shown publicly, so I have decided to reply instead.
There is a very insightful comment here [slashdot.org]
Parent
Re: (Score:3, Interesting)
It's like every /. article is an opportunity to espouse the same posts in a previous article. Let me save all the future posters their breathe...
Dirty energy is bad.
Global Warming.
Creationists are dumb.
DMCA is stoopid.
OMG zero day is here!
There, someone e-mail me when there's a comment worth reading.
I think there's some inherent vulnerability of internet discussion sites to virulent memes. If you look at Digg at the moment it's got to the point where 50% of the stories on the front page are some dubious looking slur on Palin. A few months ago 50% of them where dubious looking slurs on Hilary. And a few months before that they were all posts containing that 09 F9 magic key. 4chan is plagued by self replicating javascripts because it doesn't have a CAPTCHA, but digg and slashdot get a different sort of r
Re: (Score:3, Funny)
It's like the Republican convention, without the funny hats.
Re: (Score:3, Funny)
Re:Rudimentary (Score:5, Informative)
That's been illegal in the U.S. for cows for many years. I'm not sure about the current law for chickens. From a 2003 USAToday [usatoday.com] article:
Parent
Re: (Score:3, Informative)
Mad cow disease, just so you understand it, is prion based. It does not just randomly happen. It is impossible for the brain to just make up prions. It must first come in contact with them by consumption or injection. Considering the fact that no one goes around injecting the bovine population with syringes filled with prions we must conclude a cow get's them by ingestion. That would mean that a "mad cow" infected anim
Re: (Score:3, Informative)
Since both sheep and cows are ruminants, that would mean that they aren't fed to each other. At least sheep wouldn't be fed to cows, the quote doesn't state anything about sheep feed.
Re:Rudimentary (Score:5, Informative)
That's been illegal in the U.S. for cows for many years.
Not so. The FDA ban on feeding cattle protein to cattle excepts proteins derived from blood products and fat, and beef tallow is still used as a feed supplement at cattle farms. Also, since the bovine meat and bonemeal that used to be fed to cattle are still fed to other food stock like pigs and chickens - whose meal is, in turn, an accepted protein supplement for cattle - there is still a chance that infectious prions could find their way back into cattle (and us). Check out Michael Pollan's book, The Omnivore's Dilemma, for more info.
Parent
Re: (Score:3)
"Become a vegetarian and loose the risk of contracting a scary prion disease from your food."
The incidence of that scary prion disease in humans is extremely low. Even the the UK, where 400,000 infected cattle entered the food chain in the 1980s, has only had 193 cases (suspected and confirmed) over 25 years in a population of over 60 million people, and their figures are more accurate than anyone else's because they're the only country to have instituted mandatory reporting of cases with symptoms that even