Ecolog, Malcolm: In digging around the Internet, I unearthed the following references. I hope that y'all will help me to further understand the importance of this discovery, and any possible lines of relevance to evolution in general and arsenic "use" in other organisms and how those uses differ and resemble each other.
"Transmission electron microscopy revealed large vacuole-like regions in +As/-P grown cells that may account for this increase in size (Fig. 1E). These experiments demonstrated arsenate-dependent growth, morphological differences in GFAJ-1 driven by AsO4 3- in the growth medium, and the fact that the level of PO4 3- impurities in the medium was insufficient to elicit growth in the control (-As/-P)." A Bacterium That Can Grow by Using Arsenic Instead of Phosphorus Felisa Wolfe-Simon,1,2* Jodi Switzer Blum,2 Thomas R. Kulp,2 Gwyneth W. Gordon,3 Shelley E. Hoeft,2 Jennifer Pett-Ridge,4 John F. Stolz,5 Samuel M. Webb,6 Peter K. Weber,4 Paul C. W. Davies,1,7 Ariel D. Anbar,1,3,8 Ronald S. Oremland2 1NASA Astrobiology Institute, USA. 2U.S. Geological Survey, Menlo Park, CA, USA. 3School of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA. 4Lawrence Livermore National Laboratory, Livermore, CA, USA. 5Department of Biological Sciences, Duquesne University, Pittsburgh, PA, USA. 6Stanford Synchrotron Radiation Lightsource, Menlo Park, CA, USA. 7BEYOND: Center for Fundamental Concepts in Science, Arizona State University, Tempe, AZ, USA. 8Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ, USA. *To whom correspondence should be addressed. E-mail: felisawolfesi...@gmail.com http://lqma.ifas.ufl.edu/PUBLICATION/Lombi-02.pdf X-ray microanalyses also revealed that As was localized in the central intracellular portion of cut cells. Since the majority of this area is occupied by the vacuole, this suggests that As was mainly contained in the vacuoles (Fig. 4). This is supported by the differences between the distribution of Si and As (Fig. 3). Both elements are mainly concentrated in the epidermal cells but Si appears to be localized in the external cell walls whereas As is more evenly distributed in the epidermal cells. This finding is in agreement with observed distributions of heavy metals in hyperaccumulating plants and indicates that compartmentalization of both metals and metalloids in cell vacuoles plays a key role in terms of metal/metalloid tolerance in these plants. Thank you for your generosity in sharing your knowledge freely with the world through Ecolog. WT ----- Original Message ----- From: "malcolm McCallum" <malcolm.mccal...@herpconbio.org> To: <ECOLOG-L@LISTSERV.UMD.EDU> Sent: Thursday, December 02, 2010 4:56 PM Subject: [ECOLOG-L] life that uses Arsenic in place of phosphorus For those who have not heard.... NASA today announced that research done through their exobiology program discovered a that a bacterium living in Mono Lake, California can use Arsenic in place of phosphorus. This is being pretty hyped in the news as a new form of life. I think the aspect regarding its impact on extraterestrial life is over-hyped and frankly a stretch. We are not looking at an organism THAT USES Arsenic instead of phosporus. We are looking at an organism that CAN OPPORTUNISTICALLY USE Arsenic in place of phosphorus. This is pretty cool, and a huge scientific finding. however, I guess our anti-intellectual society would find it very difficult to appreciate that this is a big deal, so we have to promote the least interesting component of the study, the most speculative, and frankly the part that is hardly related to these findings,...that extraterrestrial life could use Arsenic. In fact, this DOES NOT REDEFINE our understanding of life, it REAFFIRMS our understanding!!! This is another adaptation that evolved from species with normal phosphorus-based physiology that resides in a high-arsenic environment. We long believed that organisms should be able to do this, and now they found one that could. Also, they have not established whether these organisms do this in the environment, only that they can do it in the lab. Understand, I am not taking away from the extreme importance of their findings, I just wish we would actually revel in their findings instead of speculation that has not been established. Here is a link to the NASA announcement: http://www.nasa.gov/topics/universe/features/astrobiology_toxic_chemical.html -- Malcolm L. McCallum Managing Editor, Herpetological Conservation and Biology "Peer pressure is designed to contain anyone with a sense of drive" - Allan Nation 1880's: "There's lots of good fish in the sea" W.S. Gilbert 1990's: Many fish stocks depleted due to overfishing, habitat loss, and pollution. 2000: Marine reserves, ecosystem restoration, and pollution reduction MAY help restore populations. 2022: Soylent Green is People! Confidentiality Notice: This e-mail message, including any attachments, is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply e-mail and destroy all copies of the original message. -------------------------------------------------------------------------------- No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.5.449 / Virus Database: 271.1.1/3291 - Release Date: 12/01/10 07:34:00
