Organisms that breathe arsenic discovered in the Pacific Ocean

newatlas.com

40 points·sahin-boydas··5 comments

This article links to an uncritical report on the controversial GFAJ-1 finding, which is widely considered to be erroneous:

https://en.wikipedia.org/wiki/GFAJ-1#Criticism

Why should I believe it's correct this time?

The Felisa Wolfe-Simon / NASA debacle from 2010 was trying to claim that GFAJ was using Arsenic in place of Phosphorus in biomolecules (especially the DNA backbone). This was quickly debunked.

The paper (indirectly) cited here is claiming that some micro-organisms use simple Arsenic-containing ions for electron transport as part of their metabolic cycles. This is a much less outrageous claim and, I think, already documented in high-Arsenic environments. The only big deal here is, I believe, that this is a low-Arsenic environment.

Original paper: http://sci-hub.tw/https://doi.org/10.1073/pnas.1818349116

> they are expressing the genes for it in an environment that is fairly low in arsenic

How does one measure this?

The arsenic or the genes?

Arsenic would probably be via mass spectroscopy, the genes would be via transcrptomics.

I meant the combination of both. You'd have to perform transcriptomics on a live microbial organism in the right environment, which (I suspect) is quite challenging. Every attempt at taking a sample or performing a measurement could (I suppose) trigger the organism to shut down the pathways that you're interested in.

Reply on news.ycombinator.com