Arsenic Life

There's been several articles about this recently, and I've been remiss in not actually writing about them. Last year an article (http://www.sciencemag.org/content/332/6034/1163.long) was published that described a bacterium that broke the basic rules of biology and was able to grow in the presence of arsenic, with no phosphorous present. Phosphorous is one of the basic building blocks of life and is required for DNA synthesis (among other things). The authors reported that the bacteria GFAJ-1 substituted arsenic for phosphorous to sustain growth. This article sparked a lot of controversy and several labs tried to independently verify the original study. None were able to do so.

http://www.jbc.org/content/early/2012/07/13/jbc.C112.394403.full.pdf+html
This article describes the arsenic causing ribosome breakdown, that released phosphorous that the bacteria was able to use to survive. They show the same phenomena occurs with E. coli.

http://www.sciencemag.org/content/337/6093/470.abstract
In this paper they state that they were unable to detect arsenic from the DNA of cells grown in the presence of arsenic, refuting the original paper.

http://www.sciencemag.org/content/337/6093/467.abstract
A paper published at the same time as the above also refutes the original paper. The authors found that the bacteria was able to grow in low phosphorous, high arsenic environments, but that phosphorous was necessary for growth. They conclude that GFAJ-1 is an arsenic resistant, phosphorous dependent bacteria.


I've started playing Scrabble online, so I will now include a Scrabble Word of the Day and points it earned with each post. Today's Scrabble Word of the Day "zeroth" for 76 points.

Christina