분자유전학실험실 (단국대학교 분자생물학과)



 이성욱 ( 2012-07-16 12:10:30 , Hit : 2482
 Arsenic-loving bacterium needs phosphorus after all

Two teams repeat much-debated study, and find that the chemical rules of life remain unbroken.

Quirin Schiermeier 09 July 2012
  

After 18 months of controversy, the official verdict is in: an arsenic-tolerant bacterium found in California’s Mono Lake cannot live without phosphorus.

In 2010, a group led by Felisa Wolfe-Simon, a microbiologist now at the Lawrence Berkeley National Laboratory in Berkeley, California, reported online in Science1 that the Halomonadaceae bacterium GFAJ-1 could include atoms of arsenic instead of phosphorus in crucial biochemicals such as DNA.


GFAJ-1 bacteria can live in high concentrations of arsenic — but do not incorporate the element in to their DNA.

Science/AAAS
The bacteria were discovered thriving in the arsenic-rich sediment of the shallow saline Mono Lake, famed for its appearance on a picture-postcard insert to Pink Floyd’s 1975 album Wish You Were Here.

All known forms of life depend on at least six elements: hydrogen, carbon, nitrogen, oxygen, phosphorus and sulphur. Arsenic has some chemical similarities with phosphorus, but is usually toxic to life, so the suggestion that it could sustain life triggered a storm of questions, as well as criticism about how the find was revealed at an enthusiastic NASA press conference (see ‘Microbe gets toxic response’).

As a result of the controversy, when Wolfe-Simon's paper appeared in print in Science last June, it was accompanied by eight technical comments2–9 from scientists responding to it.

Related stories
Study challenges existence of arsenic-based life
Open research casts doubt on arsenic life
Microbe gets toxic response
More related stories
Rosie Redfield, a microbiologist at the University of British Columbia in Vancouver, Canada, set about testing the finding. Earlier this year, she said that she could not reproduce Wolfe-Simon’s results in laboratory experiments (see ‘Study challenges existence of arsenic-based life’).

Redfield is now a co-author of one of two papers that confirm that, although the bacteria can tolerate arsenic, they do depend on phosphorus. The papers were published10, 11 by Science on 8 July.

Toxicity tolerance
Redfield and her colleagues report10 that when GFAJ-1 bacteria were grown in a medium containing arsenic and a very small amount of phosphorus, their DNA contained no detectable arsenic compounds, such as arsenate (the arsenic analogue of phosphate). In the second paper, Julia Vorholt, a microbiologist at the Federal Institute of Technology in Zurich, Switzerland, and her colleagues report11 that the bacterium cannot grow in a phosphorus-free medium in the presence of arsenate. It can, however, grow in low-phosphate conditions in the presence of arsenate. GFAJ-1 “is an arsenate-resistant, but still a phosphate-dependent bacterium”, the team writes.

“I think we have now very solid evidence that the metabolism of GFAJ-1 is as dependent on phosphorus, as are all other known forms of organic life,” says Vorholt. “These very robust and very well-adapted microbes appear to be able to efficiently extract nutrients from their extremely phosphorus-poor environments.”

The samples that Wolfe-Simon’s team had used for their original experiments apparently contained larger concentrations of phosphorus than was first thought, Vorholt adds.

In a statement, Science said: “The new research shows that GFAJ-1 does not break the long-held rules of life, contrary to how Wolfe-Simon had interpreted her group’s data.”

"The original GFAJ-1 paper emphasized tolerance to arsenic, but suggested the cells required phosphorus, as seen in these two new papers," says Wolfe-Simon. "However, our data implied that a very small amount of arsenate may be incorporated into cells and biomolecules, helping cells to survive in environments of high arsenate and very low phosphate. Such low amounts of arsenic incorporation may be challenging to find and unstable once cells are opened."

The story of GFAJ-1 is far from over, she adds. "The key questions are: how do these cells thrive in lethal concentrations of arsenic? And where does the arsenic go?"

Journal name:
Nature
DOI:
doi:10.1038/nature.2012.10971
References
Wolfe-Simon, F. et al. Science 332, 1163–1166 (2011).

ArticlePubMedISIChemPortShow context
Cotner, J. B. & Hall, E. K. Science http://dx.doi.org/10.1126/science.1201943 (2011).

ArticlePubMedChemPortShow context
Benner, S. A. Science http://dx.doi.org/10.1126/science.1201304 (2011).

Show context
Schoepp-Cothenet, B. et al. Science http://dx.doi.org/10.1126/science.1201438 (2011).

Show context
Foster, P. L. Science http://dx.doi.org/10.1126/science.1201551 (2011).

Show context
Csabai, I. & Szathmáry, E. Science http://dx.doi.org/10.1126/science.1201399 (2011).

Show context
Borhani, D. W. Science http://dx.doi.org/10.1126/science.1201255 (2011).

Show context
Redfield, R. J. Science http://dx.doi.org/10.1126/science.1201482 (2011).

Show context
Oehler, S. Science http://dx.doi.org/10.1126/science.1201381 (2011).

Show context
Reaves, M. L., Sinha, S., Rabinowitz, J. D., Kruglyak, L. & Redfield, R. J. Science http://dx.doi.org/10.1126/science.1219861 (2012).

Show context
Erb, T. J., Kiefer, P., Hattendorf, B., Günther, D. & Vorholt, J. A. Science http://dx.doi.org/10.1126/science.1218455 (2012).

Show contextRelated stories and links







667   인간게놈 정밀 분석한 ‘게놈 세밀지도’ 완성  이성욱 2012/09/06 2681
666   유전자 치료를 통한 실험쥐 후각능력의 회복  이성욱 2012/09/06 3296
665   Scientists create sperm from skin sample  이성욱 2012/08/31 2471
664   미국 연구진, '여성행복 유전자' 존재 규명  이성욱 2012/08/30 3125
663   새롭게 밝혀진 정액(semen)의 비밀  이성욱 2012/08/24 3129
662   암 유전자를 차단하는 새로운 나노 입자  이성욱 2012/08/20 2683
661   혈액형에 따라 다른 심장병 발병 위험성  이성욱 2012/08/17 3101
660   여성이 남성보다 편두통을 더 자주 앓는 이유는?  이성욱 2012/08/17 2718
659   Stem-cell pioneer banks on future therapies  이성욱 2012/08/14 2268
658   세계 첫 ‘항체 바이오복제약’ 국내서 나온다  이성욱 2012/08/03 3486
657   항바이러스 효과를 보인 우울증 치료제 프로작  이성욱 2012/08/01 3485
656   세균을 이용하여 악성 뇌종양을 치료할 수 있을까?  이성욱 2012/08/01 3323
655   European regulators back first gene therapy drug  이성욱 2012/07/24 2669
654   유럽서 유전자치료 가능해 질 듯  이성욱 2012/07/23 3020
653   Global pharma spending "to hit nearly $1.2 trillion by 2016"  이성욱 2012/07/17 2783
  Arsenic-loving bacterium needs phosphorus after all  이성욱 2012/07/16 2482
651   Five Mutations Make H5N1 Airborne  이성욱 2012/06/23 2229
650   배아 발달 동안 돌연변이와 성인에서 암 발병 관련성  이성욱 2012/06/18 2940
649   일본 연구팀이 면역 결핍 돼지의 개발에 세계 최초로 성공  이성욱 2012/06/18 3067
648   감염에 의한 발암 방법  이성욱 2012/06/15 2770

[이전 10개] [1].. 31 [32][33][34][35][36][37][38][39][40]..[64] [다음 10개]
 

Copyright 1999-2021 Zeroboard / skin by ROBIN