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 Post subject: Re: THE GREAT QUIZ CHAT
Unread postPosted: Thu Dec 02, 2010 11:16 am 
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:shock: Sounds exciting :dance:


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 Post subject: Re: THE GREAT QUIZ CHAT
Unread postPosted: Fri Dec 03, 2010 8:30 am 
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It was an exciting announcement!! :dance: to think that there is life on earth that does not conform to what we believed to be the only building blocks of DNA is amazing! and will completely change the way of thinking in a number of fields of biology :dance:

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Poison Nil: Mono Lake Bacterium Exhibits Exotic Arsenic-Driven Biological Activity
A microbe in California's arsenic-rich lake can use the element, usually a poison, as a building block for DNA and other biomolecules
By John Matson December 2, 2010 18

POISON-PROOF: A scanning electron micrograph shows the GFAJ-1 strain grown with arsenic.
Image: Science/AAAS
Life as we know it is remarkably diverse and adaptive, permitting organisms to gain a toehold in some of the most outwardly inhospitable places on the planet. But it tends to rely on a tidy, predictable array of six nutrient elements, a modest alphabet of basic biology that leaves open the possibility of other combinations making up entirely different kinds of biological activity. Life as we know it, then, might not be all there is—for either terrestrial or extraterrestrial biology.

That possibility looks more promising in the light of a new study describing a bacterium isolated from California's Mono Lake that can use arsenic, which is usually poisonous to life, as one of its key nutrient elements. The microbe can even take up arsenic into its biomolecules, replacing phosphorus as a structural building block in DNA and possibly in energy-carrying molecules such as adenosine triphosphate (ATP) as well. The study appeared online December 2 in Science.

"This is a real breakthrough, a real surprise to me as well," says study co-author Ronald Oremland, a geomicrobiologist with the U.S. Geological Survey (USGS) in Menlo Park, Calif. "We have a new element in the group of six that, at least for this organism, can sustain life." The standard six nutrients are carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur.

Oremland had previously discovered bacteria in the hypersaline, arsenic-rich Mono Lake that use the usually toxic element in photosynthesis or respiration reactions, but no one had demonstrated the uptake of the element for internal use. He says that he kept running into fellow geomicrobiologist Felisa Wolfe-Simon, the new study's first author, at meetings, and that Wolfe-Simon raised a provocative question: What about arsenic, in the form of the arsenate ion, subbing for phosphate ions inside the cell? After all, arsenic is the downstairs neighbor to phosphorus on the periodic table of the elements, and phosphate and arsenate are chemical cousins. That similarity contributes to arsenic's toxicity—arsenate masquerades as the nutrient phosphate and thus gains access to the body's metabolic system.

Oremland was not initially convinced by Wolfe-Simon's idea. "I looked at her like she was a nutcase," he says. But Wolfe-Simon and her colleagues continued to develop the hypothesis, and earlier this year she joined Oremland at USGS on a NASA astrobiology fellowship.

To look for organisms that could use arsenic as a nutrient, the researchers inoculated sediments from Mono Lake into a growth medium, adding arsenic but not phosphorus. They isolated a strain of gammaproteobacteria called GFAJ-1 that grew in arsenate-rich conditions but did not grow when deprived of both arsenate and phosphate. "It grows better with phosphorus, but it grows just fine with arsenic," Oremland says.

"We kept on saying this can't be real, we must be missing something," he adds. But after a suite of high-tech analyses—x-ray spectroscopy, radioisotope tracers, mass spectroscopy—the researchers found that arsenate was indeed being incorporated into biomolecules, including the backbone of DNA, a slot usually occupied by phosphate.

The thoroughness of the analysis lends weight to the claim, says Dirk Schulze-Makuch, an astrobiologist at Washington State University in Pullman who was not involved in the research. "This is the first time that I've really seen good evidence that this has happened," he says. "You can't really look at one DNA molecule and say, okay, there's an arsenic, there's an arsenic." But the complementary tests can reveal the element's role within the microbes. "If you put this all together you can make a very convincing case," Schulze-Makuch says.

Just why the bacterium has a penchant for arsenic is not yet clear. Perhaps some life-forms evolved in an arsenic-rich environment and later migrated to a more typical region of Earth, where phosphorus is far more abundant. "Life might have been adapted for the use of arsenic and/or phosphorus," Oremland says. "Maybe that's one way to view this, but that's entirely conjecture."

Prior to the study's publication, speculation ran wild across Twitter and the blogosphere and in British newspapers after a NASA press release announced a December 2 news conference "to discuss an astrobiology finding that will impact the search for evidence of extraterrestrial life." One popular blog, kottke.org, stirred up a minor frenzy with the headline "Has NASA discovered extraterrestrial life?"

Some will undoubtedly be disappointed by the answer to that question and by the downright terrestrial nature of the new results. But the research nonetheless has implications for the myriad kinds of life that astrobiologists might someday find in the solar system or beyond. "This study really drives the point home of how adaptive life can be and that we should go out expecting the unexpected," Schulze-Makuch says. "If you look at other places, from the hydrocarbon lakes of Titan to the subsurface ocean of Europa to the deserts of Mars, we really should not underestimate the abilities of life to adapt to these places."
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 Post subject: Re: THE GREAT QUIZ CHAT
Unread postPosted: Tue Dec 21, 2010 9:00 am 
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It seems a lot of 'mites are already gone, and others are on their respective ways. I'll still be around for the week and again next week, but let me now, while there's at least still some people around, wish each and every one a Merry CHRISTmas, and a Happy New Year. It has been a touch year, but also a wonderful year. Enjoy the rest, even if you are resting only a day or two. If you travel, do so safely - come back home safely in your car, and not in the newpapers! And then let's tackle the new year, 2011, with zest!

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Hunter, nature lover, conservationist.

I believe that for man to survive, we must work with nature rather than against her. We need the land; the land doesn't need us. Too many people have lost sight of this fact. - Bruce Truter


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 Post subject: Re: THE GREAT QUIZ CHAT
Unread postPosted: Wed Dec 22, 2010 6:50 am 
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A merry and blessed Christmas and happy and prosperous New Year to all the quizzers!!!
Take care and drive safe and enjoy the festive season!!!
I've been appointed manager of Umtsalane Private Game Farm. so a very excited new year awaits me.

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Join SABAP2.........it is the right thing to do..........and submit the birds you see in the SAN-Parks.


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 Post subject: Re: THE GREAT QUIZ CHAT
Unread postPosted: Wed Dec 22, 2010 7:52 am 
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koedoe, congrats on the appointment! May you really enjoy it thoroughly, and make every success of the adventure.

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Marius
Hunter, nature lover, conservationist.

I believe that for man to survive, we must work with nature rather than against her. We need the land; the land doesn't need us. Too many people have lost sight of this fact. - Bruce Truter


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 Post subject: Re: THE GREAT QUIZ CHAT
Unread postPosted: Wed Dec 22, 2010 11:12 pm 
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Hiya! I am back. (I hope!, although I became quite addicted to ironing over the past few weeks. Image). :tongue:


First of all, congrats on your qualification and new appointment, Koedoe. :clap: :clap: :thumbs_up: (Remember, if you need a good ironing lady, you have my PM address). :tongue:


Does anyone know what has happened to Bosnimfie's results? Please? I am sure we are all very proud of Ods who has (obviously!) passed with flying colours. :clap: :clap: :clap:


And then, of course, let me add to the well wishes above. Wishing you and your loved ones abundant blessings and joy during the Festive Season. And B3006, I am looking forward to that promised zest of yours in 2011. :P :wink:

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 Post subject: Re: THE GREAT QUIZ CHAT
Unread postPosted: Wed Dec 22, 2010 11:51 pm 
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So glad you back E :dance: :dance: Im sure the forum addiction will iron out any other addiction soon enough :wink: I remember Micetta writing about you having problems logging in when the forum was upgraded??

Have not seen BF around either :?

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 Post subject: Re: THE GREAT QUIZ CHAT
Unread postPosted: Thu Dec 23, 2010 12:51 am 
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Welcome back Elzet. Looking forward to see some of your ironing! :dance:

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 Post subject: Re: THE GREAT QUIZ CHAT
Unread postPosted: Thu Dec 23, 2010 5:04 am 
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Award: Quiz Whiz of the Year (2013)
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Award: Musketeer of the Year, Quiz Whiz of the Year (2012)
Koedoe, a very well done there, mate! You've immersed yourself in conservation and it has paid off! I wish you a prosperous and forward-facing year! :clap: :clap: :clap:

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 Post subject: Re: THE GREAT QUIZ CHAT
Unread postPosted: Fri Dec 24, 2010 11:46 am 
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Starting to pack up here at work, so I'll only be around next week sometime again. Enjoy, and be safe. :thumbs_up:

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Marius
Hunter, nature lover, conservationist.

I believe that for man to survive, we must work with nature rather than against her. We need the land; the land doesn't need us. Too many people have lost sight of this fact. - Bruce Truter


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 Post subject: Re: THE GREAT QUIZ CHAT
Unread postPosted: Fri Dec 24, 2010 12:05 pm 
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:thumbs_up: Enjoy the break!

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Want to know more about the SANParks Honorary Rangers? Visit www.sanparkshr.org


One positive deed is worth more than a thousand critical words.


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 Post subject: Re: THE GREAT QUIZ CHAT
Unread postPosted: Fri Dec 24, 2010 12:18 pm 
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Thanks :thumbs_up: B3006, OWN and Elzet :dance:
Welcome back Zettie :dance: I'll consider you strongly for the ironing post....haha :twisted: jy weet jy is altyd wekom om net te kom kuier
BushFairy is in Kenton on Sea at present. After her exams she spent 2 weeks in Moz to catch that big barracuda. I haven't heard of any results.

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* Please support the anti-poaching campaign! *

Join SABAP2.........it is the right thing to do..........and submit the birds you see in the SAN-Parks.


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 Post subject: Re: THE GREAT QUIZ CHAT
Unread postPosted: Sat Dec 25, 2010 6:16 am 
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Merry Christmas to all the quizzers!!!!!

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Philip


* Please support the anti-poaching campaign! *

Join SABAP2.........it is the right thing to do..........and submit the birds you see in the SAN-Parks.


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 Post subject: Re: THE GREAT QUIZ CHAT
Unread postPosted: Sat Dec 25, 2010 8:30 am 
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Merry Christmas to all and may you all enjoy your holidays and drive safely. Looking forward to a new year on the forums.

[ Post made via Mobile Device ] Image


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 Post subject: Re: THE GREAT QUIZ CHAT
Unread postPosted: Fri Jan 28, 2011 10:49 pm 
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I have limited internet connectivity until Monday. Forgive me if I am not too active. Will be around, but not posting too much.

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Want to know more about the SANParks Honorary Rangers? Visit www.sanparkshr.org


One positive deed is worth more than a thousand critical words.


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