Navigation Links
From toxicity to life: Arsenic proves to be a building block
Date:12/2/2010

LIVERMORE, Calif. - Arsenic - an element that triggers death for most Earthly life forms - is actually allowing for a bacterium to thrive and reproduce.

In a study that may prompt the rewriting of textbooks, a team of astrobiologists and chemists has found the first known living organism that can use arsenic in place of phosphorus in its major macromolecules. The new findings, published in the Dec. 2 Science Express, could redefine origins of life research and alter the way we describe life as we know it.

Oxygen, carbon, hydrogen, nitrogen, sulfur and phosphorous are the six basic building blocks of life on Earth. These elements make up nucleic acids, proteins and lipids - the bulk of living matter.

The new study by Lawrence Livermore National Laboratory and led by NASA and the U.S. Geological Survey has found that a bacterium isolated from Mono Lake may substitute arsenic for phosphorus to sustain its growth.

Mono Lake, located in eastern California, is an alkaline and hypersaline lake with high dissolved arsenic concentrations and is believed to have formed more than 760,000 years ago from neighboring volcanic eruptions.

Felisa Wolfe-Simon, a NASA astrobiology research fellow in residence at the USGS and the paper's lead author, has been studying possible arsenic based life forms at the lake for some time. Using samples from Mono Lake and a culture medium with reduced phosphorus levels, she showed that that a strain of Gamaproteobacteria can not only survive using arsenic but can grow as well.

"We know that some microbes can 'breathe' arsenic, but what we've found is a microbe doing something new - building parts of itself out of arsenic," Wolfe-Simon, said.

LLNL's Jennifer Pett-Ridge and Peter Weber were able to identify low concentrations of arsenic found in individual cells of bacteria and extracted DNA. NanoSIMS is a tool which allows precise, spatially explicit, elemental and isotopic analysis down to the 50-nanomenter scale; it also offers a range of advantages for sensitive and high-resolution measurements.

"It turned out the organism was able to tolerate these heavy metal concentrations (that are found in Mono Lake)," Pett-Ridge said. "Arsenic is right below phosphorous on the periodic table and it may have found a way to substitute arsenic for phosphorous in its biological makeup."

Cultures of the Mono Lake samples produced flourishing colonies of the bacterium cells, as expected, when fed a steady supply of phosphorus, along with other necessities. When researchers removed the phosphorus and replaced it with arsenic, however, the microbes continued to grow. Subsequent analyses indicated that the arsenic was being used to produce the building blocks of new cells.

"The team hasn't yet established how the organism uses arsenic as a building block when it's a poison to most other life forms," Pett-Ridge said. "It could be an ancestral trait or a unique kind of metabolism. Or it could be that it lives in an environment where arsenic is very high and it found a niche to survive."

"This organisms' metabolic lifestyle suggests that life based on non-typical elements may be possible," Wolfe-Simon said. "This is important to scientists looking for clues to life on other planets."

NanoSIMS not only measures the elemental concentrations, but it also images them. It collects a picture of the image and identifies how much of a specific element is found in the sample. "We found that arsenic was higher in the cells than in the environment outside the cells," Pett-Ridge said.

"It's very difficult to make these measurements because the sample concentrations of arsenic are very low," she said. "But it's clear that the cells are incorporating arsenic into them. There are not a lot of organisms on the planet that can do this. "

The next step is to conduct protein biochemistry to find out if there are specific enzymes that help transport arsenic into the cells. Other collaborators include NASA Astrobiology Institute, Arizona State University, Duquesne University, Stanford Synchrotron Radiation Lightsource and BEYOND: Center for Fundamental Concepts in Science at Arizona State University.


'/>"/>

Contact: Anne Stark
stark8@llnl.gov
925-422-9799
DOE/Lawrence Livermore National Laboratory
Source:Eurekalert

Related biology news :

1. UC Riverside biochemists devise method for bypassing aluminum toxicity effects in plants
2. Where theres wildfire smoke, theres toxicity
3. Nanoparticle toxicity doesnt get wacky at the smallest sizes
4. Countries unite to reduce animal use in product toxicity testing worldwide
5. Gene mutation increases drug toxicity, rejection risk in pediatric kidney transplants
6. Springer to publish Neurotoxicity Research
7. A breath of fresh air could improve drug toxicity screening
8. UR study reveals chemos toxicity to brain, possible treatment
9. Kill the cancer, not the patient: New toxicity testing approach could make chemo drugs safer
10. Gulf oil dispersants unlikely to be endocrine disruptors and have relatively low cell toxicity
11. Early-life experience linked to chronic diseases later in life: UBC research
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/2/2016)... Perimeter Surveillance & Detection Systems, Biometrics & ... & Other Service  The latest report from ... of the global Border Security market . Visiongain ... billion in 2016. Now: In November 2015 ... and hardware technologies for advanced video surveillance. ...
(Date:5/20/2016)... 20, 2016  VoiceIt is excited to announce ... By working together, VoiceIt and VoicePass ... and VoicePass take slightly different approaches to voice ... security and usability. ... new partnership. "This marketing and technology ...
(Date:5/9/2016)... May 9, 2016 Elevay is ... to expanding freedom for high net worth professionals seeking ... today,s globally connected world, there is still no substitute ... ever duplicate sealing your deal with a firm handshake. ... by taking advantage of citizenship via investment programs like ...
Breaking Biology News(10 mins):
(Date:6/24/2016)... , June 24, 2016 Epic Sciences ... detects cancers susceptible to PARP inhibitors by targeting ... cells (CTCs). The new test has already been ... in multiple cancer types. Over 230 ... damage response pathways, including PARP, ATM, ATR, DNA-PK ...
(Date:6/23/2016)... , ... June 23, 2016 , ... ... release of its second eBook, “Clinical Trials Patient Recruitment and Retention Tips.” Partnering ... retention in this eBook by providing practical tips, tools, and strategies for clinical ...
(Date:6/23/2016)... TORONTO , June 23, 2016 /PRNewswire/ - ... Ontario biotechnology company, Propellon ... the development and commercialization of a portfolio of ... cancers. Epigenetic targets such as WDR5 represent an ... contribute significantly in precision medicine for cancer patients. ...
(Date:6/23/2016)... ... 23, 2016 , ... Charm Sciences, Inc. is pleased to ... AOAC Research Institute approval 061601. , “This is another AOAC-RI approval of the ... Vice President of Regulatory and Industrial Affairs. “The Peel Plate methods perform comparably ...
Breaking Biology Technology: