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n2doc Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Aug-31-11 08:51 AM
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Scientists sequence Black Death bacteria DNA, admit they were wrong
By John Timmer |


The bacteria behind the Black Death has a very unusual history. Its ancestor is an unassuming soil bacterium and the current strains of Yersinia pestis still infects thousands of people annually, but no longer cause the suite of horrifying symptoms associated with the medieval plagues. The radical differences between the two versions, in fact, led some to suggest that we have been blaming the wrong bacteria. Now, researchers have obtained DNA from some of London's plague victims and confirmed that Y. pestis appears to be to blame. But the sequences also suggest that the strains of bacteria we see today may be different from the ones that rampaged through Europe.

What transformed soil bacteria into a human pathogen? One key event seems to have been the fact that it picked up a plasmid, a short, circular piece of DNA that can be copied separately from the rest of the organism's DNA. In the case of Y. pestis, that plasmid contained three key genes: two that helped it kill off competing bacteria, and a third that helped it manipulate the human blood clotting system. So, when presented with the opportunity to obtain the DNA of plague victims, this is the DNA the authors decided to target.

The DNA came from 53 bones and 46 teeth from the East Smithfield, a mass burial site in London that dates to the first appearance of the Black Death in Europe, from 1347-1351. This is a key resource, since the different waves of plague that swept through Europe had somewhat different behavior, suggesting that Y. pestis was already adapting to its human hosts. To serve as controls, the authors obtained bones from a set of 10 human remains that predate the appearance of the plague.

To figure out the degree of contamination, each of the sets of bones were used to search for the DNA of human mitochondria, which should provide a degree of information about the levels of damage and contamination. Some of the samples contained no DNA, but a significant number did. Contamination levels were manageable, and the sequence had the sorts of changes that are typical for older, damaged DNA. With the samples looking good, the authors turned to sequencing the Y. pestis plasmid DNA.

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http://arstechnica.com/science/news/2011/08/scientists-sequence-black-death-bacteria-dna-admit-they-were-wrong.ars
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xchrom Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Aug-31-11 08:53 AM
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1. recommend
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villager Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Aug-31-11 09:20 AM
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2. So does this mean it was *not* "Bubonic" plague!?
:shrug:
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tblue37 Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Aug-31-11 09:30 AM
Response to Reply #2
3. It WAS Bubonic Plague, but the bacterium has changed slightly
since then, which is why the symptomology of modern victims is somewhat different from that of the victims during the epidemics in Europe.

The scientists were ones who had previously argued that the two had to be different bacteria because of the different symptomology, but after checking the earlier strain's DNA, they find that it is definitely the same bacterium, but with certain changes that were caused by the bacterium's evolution as it adjusted to its human hosts.
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RaleighNCDUer Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Aug-31-11 09:38 AM
Response to Reply #3
5. IOW, it evolved slightly to become one of the world's all-time big killers,
and then evolved again, or perhaps returned, to to somewhat less virulent strain we know today.

And the poo-pooers say all the worry about Avian Flu is just scare tactics. It would only take a minor change in its DNA to become more transmissable to humans to become a new Spanish Flu, killing millions.
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Avalux Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Aug-31-11 02:21 PM
Response to Reply #5
15. It's called microevolution.....bacteria do this but over a longer period of time than viruses.
Viruses can mutate or shift from one year to the next because they don't have DNA; only RNA and they're dependent on the DNA of a host cell to replicate. Approximately every 1000th copy of a virus is a variant; not identical to the original organism.

Bird influenza A (bird flu) can be transmitted from bird to human by contamination; but it must 'change' by combining with human influenza A in a vector to become a virus that can spread easily from human to human and cause a pandemic (and depending on the strain, may or may not have a high mortality rate).

It's really only a matter of time until it happens; we just don't know when.
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TheMadMonk Donating Member (1000+ posts) Send PM | Profile | Ignore Fri Sep-02-11 12:09 AM
Response to Reply #15
21. NO! It's called evolution. "Microevolution" is a Creationist copout,...
...which allows pathogen-host type evolutionary arms races, but lets them continue to deny the posibility of hominid evolution "culminating" in Mankind. Mankind remains "always was".

Some viruses cary their own DNA, some RNA.

And the most likely pathway by which a virulent (deadly) but not particularly infectious animal pathogen becomes infectious is through combination with an already infectious strain. However, a chance mutation in exactly the wrong place can do it too.

Pardon but your "slip" does appear to be showing.
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Recursion Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Aug-31-11 09:31 AM
Response to Reply #2
4. It means the theory that it was viral hemorrhagic fever was wrong
And it explains why the 14th-17th century outbreaks were so much worse than more recent ones.
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happyslug Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Aug-31-11 10:03 AM
Response to Reply #2
7. No, just a variation of "Normal" Bubonic plague
n/t
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Odin2005 Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Sep-04-11 12:05 AM
Response to Reply #2
23. No, it's the same germ. But pathogens tend to get less virulent over time.
Edited on Sun Sep-04-11 12:07 AM by Odin2005
When Syphilis was first brought to Europe from the Americas it killed it's victims quickly, but it rapidly evolved to become the slow, multi-stage disease we know today.
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starroute Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Aug-31-11 10:00 AM
Response to Original message
6. Syphilis did much the same thing
In the 1500's, it was a rapid killer, capable of ending wars by devastating entire armies. (As I recall, a French invasion of Italy ended in that manner.) But by the 1600's, it had become something that people could live with for decades before succumbing to its ravages.

Diseases that kill off their hosts too quickly hurt their own ability to spread and are easily out-competed by variants that are less destructive -- or, even better, by those that become entirely harmless. There are theories that large chunks of our own DNA comes from viruses that opted for peaceful coexistence, and that this process supplies much of the raw material for evolutionary change.

This new discovery about the plague does leave one loose end, however. When it was thought to be a disease similar to Ebola, which is caused by a retrovirus, there was speculation that the reason why some people of European descent have natural immunity to AIDS could be that they were descended from plague survivors. Now that theory goes out the window.

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raccoon Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Aug-31-11 10:24 AM
Response to Reply #6
8. That's what I don't get about rabies. "Diseases that kill off their hosts too quickly hurt their own

ability to spread and are easily out-competed by variants that are less destructive -- or, even better, by those that become entirely harmless."

It is 100% fatal without treatment and as far as we know, it always has been.

How come it never evolved to become less fatal? :shrug:





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Maine_Nurse Donating Member (688 posts) Send PM | Profile | Ignore Wed Aug-31-11 10:46 AM
Response to Reply #8
9. It doesn't have to become less fatal...
rabies is primarily a disease of animals. With the exception of domestic dogs, where extensive prevention programs have helped greatly, the virus doesn't ever run out of hosts. It also doesn't really kill quickly, only quickly after onset of symptoms. While humans typically show symptoms within a few weeks of infection (then rapid decline to death), it may take up to a year or two to show symptoms. In that latent period (humans or critters), there is ample opportunity to spread the disease. The disease lives in the brain and there is a good chance that other critters will eat the brain of prey or carrion (soon enough after death that the virus still lives).
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raccoon Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Aug-31-11 11:27 AM
Response to Reply #9
11. Thanks for your post. I've always wondered that about rabies.

I mean, I've always wondered why it was 100% fatal.


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Maine_Nurse Donating Member (688 posts) Send PM | Profile | Ignore Wed Aug-31-11 01:33 PM
Response to Reply #11
12. By the time you show symptoms...
you are beyond treatment as the disease is in the brain where the proper antibodies and most chemicals (medicine) can't penetrate the blood-brain barrier. Although there is one recorded case of a girl that survived with no treatment.
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raccoon Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Aug-31-11 01:39 PM
Response to Reply #12
13. Tell me about that case. I did hear of a teenager from WI who had rabies

who was put into a coma, and survived.

http://www.wisn.com/r/3896365/detail.html



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raccoon Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Aug-31-11 01:46 PM
Response to Reply #13
14. There have been other survivors besides Jeanna Giese.
(Jeanna Giese) is no longer alone, no longer the sole survivor.

Despite deep skepticism from some rabies experts, Willoughby pressed on, refining the Milwaukee protocol, sharing it online, guiding doctors around the world as they tried to use it.

Often the other cases were flawed. Doctors began the treatment too late in the disease progression, or departed from the protocol in significant ways. Just the same, Willoughby counted them all as attempts.
After 33 attempts, Jeanna has been joined by four more rabies survivors around the world, though only one was unvaccinated. The new survivors, treated with the Milwaukee protocol, come from Colombia, Brazil, Peru and Qatar. Willoughby defines survivors as patients who have cleared the rabies virus from their bodies and been able to leave intensive care. If they require a breathing machine, he does not count them as survivors. If patients leave intensive care, but die later during rehabilitation, he does count them.
Two of the four survivors have died during rehabilitation. In addition to Jeanna, the two living survivors are a teenage boy in Brazil and a girl in Qatar.

http://www.jsonline.com/news/wisconsin/121479779.html
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TheMadMonk Donating Member (1000+ posts) Send PM | Profile | Ignore Fri Sep-02-11 12:18 AM
Response to Reply #11
22. There is also the behaviour altering aspect of rabies.
In it's final stages, it imbues a great savagery in it's victims.

Just like toxoplasmosis brings infected rodents within reach of felines, rabies "works" to bring about its own transmission.

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Recursion Donating Member (1000+ posts) Send PM | Profile | Ignore Thu Sep-01-11 09:20 AM
Response to Reply #8
19. We aren't a vector for it, just collateral damage
Rabies isn't "trying" to spread through humans, so it's not a selective pressure on it that it kills us quickly.
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RaleighNCDUer Donating Member (1000+ posts) Send PM | Profile | Ignore Thu Sep-01-11 08:13 PM
Response to Reply #8
20. In humans, yes. But it has other natural hosts which act as carriers
without killing them.
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happyslug Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Aug-31-11 11:09 AM
Response to Reply #6
10. This may force researchers to revisit the theory on where AIDS developed
The present theory is that European resistance to AIDs (Which get stronger the further north and east you go) is a product of Europeans developing innate resistance to ALL disease including AIDS do to exposure to the Black Death in the 1300s. This finding does NOT kill off that theory, but puts some holes into it (I should say additional holes for it was a weak theory from day one).

The spread of Syphilis through Europe and Small Pox through the New World in the 1600s are example of a new disease being introduced into a population never before exposed to that disease. Rapid died offs is the norm in such situations. AIDS rapid spread in Africa and South East Asia looks more like the Spread of Small Pox in the New World in the 1500s AND the Spread of Syphilis in Europe during the same period. i.e. a New Disease into a population never exposed to that disease before. Not only must innate immunity be developed but social structures must be changed to fight off the new disease. Example of new Social Structure in Europe do to the Black Plague., was the further advancement of people living as families inside individual homes instead of in one big hall which had been the norm prior to the 1300s (And was the Norm Among Native Americans before Small Pox hit them hard).

The issue of where AIDS developed is hard to pinpoint, most research is aimed at a African starting point. Even the Russian trace AIDS to a Russian soldier who brought it back from Africa.

The biggest problem with this line of research is a British Case from 1959. A Doctor treated a patient for a disease the Doctor could NOT determined at that time. The Patient died but the doctor kept a sample of his blood for later research if needed. The Doctor forgot about it till the 1970s when AIDS his Britain. After a couple of years treating patients with AIDs, he remembered that case from 1959, looked up the blood sample and it came up positive for AIDS. Now this is generally dismissed as a possible contamination case, but what the doctor wrote in 1959 fits untreated AIDS. The biggest problem with this case is that the Patient had been a young Sailor on a Freighter, but only sailed once, to Leningrad and then back home to England, where the Patient came down with his aliment and died.

That case, the greater resistance to AIDs as you go north and East in Europe, the broader definition of Homosexuality in Northern and Eastern Europe, i.e. any people of the same sex who has sex with another person of that same sex (As oppose to the Southern European/Mediterranean/Arab definition, which restricts the term Homosexual to those males who are penetrated, the penetrating males are NOT viewed as Homosexual under this non-Northern European definition, a definition that has also developed in the US Prison system), all indicates some exposure to AIDS as a disease coming out of present day Russia. Given the controls the Czars and later the Communists imposed on the lower classes of Russia, AIDS may have been a very local disease that people caught, but could NOT spread beyond a certain group to to the broader definition of Homosexuality, the very strong restrictions on movement imposed by the Czars and the Communists, and the high level of resistance to AIDS among people outside of the group AIDS was restricted to (The reason for the high level of resistance is that AIDs would get out, expose the surrounding population, but the fall back to its corp group). These factors, along with the poor state of Medical care under the Czars, the Communists improved on it but under Stalin of anyone found anything bad, they knew the bearing of the bad news would be punished so anything NOT in the medical journal (i.e. AIDS cases) were just not reported and listed a something else UNTIL the 1970s after AIDS had been reported in the West, and thus the Soviet Doctors could report such cases in the Soviet Union.

Given the above, an argument can be made that AIDS may be a Russian or Eurasian disease. Someone with AIDS, took it with him to Africa in the early 1970s (another person with a different variation of AIDS took it with him to South East Asia at the same time, the Soviet Union was sending Advisers to both places at that time period, late 1960s to mid 1970s). In the virgin population of Africa and South East Asia (as to AIDS) AIDS took off, like Syphilis had done in the 1500s in Europe and Small Pox had done in the New World in the 1500s. This is by far the best explanation for the spread of AIDS, but it is unpopular for it would indicate a NON-African origin of the disease.

This latest discovery as to the Black Death puts even more holes in the theory that the Black Death made the Surviving Europeans better able to resist new diseases and thus force researchers to look elsewhere for where AIDS developed.

Side Note: We tend to view people as NOT moving prior to the 1800s, and most people did not move, but some people did move and moved thousands of miles. Among the Berbers of North Africa blonds occur, do to an influx of Blond people into the people who would become the Barbers about 5000 years ago (With additional blond blood lines with the influx of the Vandals around 450 AD into Northern Africa as the Roman Empire fell). The Reverse is also possible, a group of Africans, moving to what is now Russia about the same time period do to the drying up of what is now the Sahara Desert. The people living in that grasslands of 5000 years ago had to go somewhere, and may have skipped over Egypt (Where many other people from the Sahara moved to a developed Ancient Egypt) and then traveled north till they entered what is Now Russia, an area with low human population AND plenty of water at that time period. Nothing has been found to show such a move, but it is possible and that is how AIDs may have found its way into Russia.

Another alternative is during the expansion of the Persian Empire in the early 600s (Where, for the first time since the time of Alexander the great, a Persian army was on the Mediterranean Sea AND held Egypt, through only for about 10 years, then it collapsed under Pressure from what is called the Byzantine Empire, and 10 years afterward by the Arab conquest), Persia held onto not only Egypt but Yemen. Constantinople, capital of the Byzantine Empire, seeing this development asked and received help from Ethiopia in the form of Ethiopian troops being sent to Yemen in Southern Arabia to take Yemen back from Persia. In such an invasion AIDS could have come with the Ethiopia Troops and then taken North by the retreating Persians. Later one the Persians took it to the Persian speaking people of what is now referred to as the Former Soviet Central Asiatic Republics (Uzbek and Khazar are variations of Iranian the Language of Persia/Iran). The Ancient Scythians (By the late Rome Empire referred to as Avers, who were allied with the Slavs and the Persians during this period) could have been infected via Persia (If some Avars did NOT go directly to Yemen, something NOT unheard of at the time). Again prue speculation but could explain HOW AIDs entered Russia long after it had died out in Africa (If AIDs developed in Africa).

Just something to think about when it comes to diseases and their spread.

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Avalux Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Aug-31-11 02:26 PM
Response to Reply #10
16. Did you write this or is there a link? And BTW...it's HIV, not AIDs.
Human Immunodeficiency Virus (HIV) is the culprit and AIDs is the syndrome that describes the illnesses and symptoms that develop once the virus has destroyed a person's immune system.

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happyslug Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Aug-31-11 04:59 PM
Response to Reply #16
17. The report of increased immunity as you go north and east is from a 1990sScientific American Article
Now, that was at the time period where it was believed their was two types of HIV virus, a relatively minor one, that slowly attacked the body, then it evolved to a deadly form that killed the person affected.

Since that time, the theory on HIV has changed. Present theory is that AIDS infects a body, and then the White Blood cells attack the AIDS Virus. As the Body kills off more and more of the HIV infection, it changes its outer shell thus becoming a new infection. The body takes a while to recognize this as a new threat. During this period, the new form of HIV expands, then this new form is beaten back by the body. This repeats over and over again, with each new version of HIV making the body weaker and weaker. After several such ups and down, the body is overwhelmed by the latest version of HIV and that body dies.

I have read up on AIDS/HIV every since the days of Reagan. I have followed how the treatment for AIDS has changed over the years. I have had several clients with AIDS who I tried to get Social Security for (The test requires someone to meet certain requirements, I had one client who test were just short of the requirements and was denied Social Security Disability for that reason, I told him to re-apply and on his second application was awarded Social Security Disability do to how close he was to matching every requirement of the Social Security Listing for AIDS).

I have also read other things, including the history of Small Pox and Native Americans. The Persian Wars of the late Roman Empire and the Arab Conquest including who did what at that time period. Some of this has been done on line, but much of it predates the Net so it was from Books, books I no longer have ready access to thus no citation. In my opinion that is a problem for anyone reading what I wrote have no way to double check what I said (And neither do I), but at the same time some of this facts need to be brought up and discussed and thus I type what I type.
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Avalux Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Aug-31-11 09:42 PM
Response to Reply #17
18. What you've written is incorrect.
If you wish, I can provide you with information explaining how HIV infects cells, replicates, mutates; and how antiretrovirals work.

Until you understand the facts, please refrain from posting nonsense like this.

















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Odin2005 Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Sep-04-11 12:18 AM
Response to Reply #10
25. Your idea about HIV is total nonsense. HIV is derived from a chimpanzee disease...
Edited on Sun Sep-04-11 12:19 AM by Odin2005
that jumped to humans when folks involved in the bushmeat trade came in contact with the blood of infected chimps. The genetic evidence PROVES IT, HIV developed from the chimp virus very recently, no earlier than about 150 years ago.
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Odin2005 Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Sep-04-11 12:09 AM
Response to Reply #6
24. DOH, I posted the same thing about syphilis before seeing your post!
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