Two new papers published in Science have contributed to the continuing debate on ongoing discussion on the role of arsenic in the bacterial isolate GFAJ-1.
In December 2010, Felisa Wolfe-Simon and colleagues published a paper, also in Science, which proposed that GFAJ-1 could substitute small amounts of phosphorus in its DNA with arsenic. This claim would have significant implications for our understanding of life, since all known forms of life on Earth typically use oxygen, carbon, hydrogen, phosphorus and sulfur.
Now, groups from ETH Zürich, and the University of British Columbia and Princeton University have conducted independent studies which show that GFAJ-1 cannot substitute arsenic for phosphorus to survive.
The ETH Zürich group, including JAAS Editorial Board Chair Detlef Günther, combined physiological experiments with ICP-OES and ICP-MS to provide evidence that whilst GFAJ-1 is highly resistant to arsenate, but still requires phosphate for growth. Rosie Redfield of the University of British Columbia and collaborators at Princeton demonstrated that GFAJ-1 does not require arsenate for growth in media with any level of phosphate, and used mass spectrometry to show no detectable covalently bound arsenate to its DNA.
GFAJ-1 Is an Arsenate-Resistant, Phosphate-Dependent Organism
Tobias J. Erb, Patrick Kiefer, Bodo Hattendorf, Detlef Günther, Julia A. Vorholt
Absence of Detectable Arsenate in DNA from Arsenate-Grown GFAJ-1 Cells
Marshall Louis Reaves, Sunita Sinha, Joshua D. Rabinowitz, Leonid Kruglyak, Rosemary J. Redfield
The discussion will undoubtedly go on, with many further avenues for research. If you’re on Twitter, follow us, and get the latest on this story using #arseniclife
Not as controversial, but still of interest, take a look at some recent content in Metallomics on arsenic:
Perspective: Carcinogenic metals and the epigenome: understanding the effect of nickel, arsenic, and chromium
Yana Chervona, Adriana Arita and Max Costa
Metallomics, 2012,4, 619-627
Perspective: Arsenic metabolism and thioarsenicals
Kanwal Rehman and Hua Naranmandura
Metallomics, 2012, Advance Article
Minireview: Genetic and epigenetic effects of environmental arsenicals
Toby G. Rossman and Catherine B. Klein
Metallomics, 2011,3, 1135-1141
Selenium effects on arsenic cytotoxicity and protein phosphorylation in human kidney cells using chip-based nanoLC-MS/MS
Orkun Alp, Yaofang Zhang, Edward J. Merino and Joseph A. Caruso
Metallomics, 2011,3, 482-490