Field of Science

Now no growth in arsenate

Results from growing phosphate-limited GFAJ-1 with and without 40 mM arsenate for 40 hr, in new screw-capped plastic tubes:

This is good in that growth in the absence of arsenate is cleanly limited by the amount of phosphate the medium contains.  A parallel culture with 1500 ┬ÁM phosphate reached an OD of 0.63.  But the cells in medium with 40 mM arsenate don't appear to have grown at all.

I'm away for the rest of the week (Science Online London!), so I put the tubes back into the incubator, to see if the arsenate cultures just grow  v-e-r-y  s-l-o-w-l-y.

Two weeks later:  No, the arsenate cultures didn't grow at all.


  1. Screw-capped plastic tubes are kewl

  2. Jest to let Rosie know, many of us (including me) are still very excited about this stuff.

    What troubles me is that you saw growth in As+ conditions in your previous experiments...I am having trouble coming up with an explanation that makes sense...


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