The controversy of arsenic

We are taught that life is based on phosphate for being an essential part of DNA and RNA. The phosphorus chemical has properties like arsenic, but being a semi-metal, is toxic to living organisms. A study carried out under the supervision of geo-microbiology Geological Survey Agency (USGS) evidence that a proteobacterium of the family Halomonadaceae could prove a kind of life forms that not only tolerate it.


According to the quote of Mary Voytek, the program director of the NASA Astrobiology: “In our mind this is like the equivalent of finding a creature as Horta from Star Trek.”


Scientist isolate bacteria from Mono Lake, located in the mountains of Mammoth, eastern California. Was formed as a consequence of a volcanic eruption more than 760,000 years, so it is considered one of the oldest lakes in America. This bacterias were submit to a different phosphorus and arsenic concentrations. The results that were detached were conclusive: this organisms continued to live and multiply only with arsenicUnlike other organisms, rather than breathe arsenic, it seems that it invests in its structures, its DNA, replacing phosphorus in all its functions.


The results will be applied in the research for life on other planets, to understand the evolution of life on Earth and to advance fields as organic chemistry, biogeochemical cycles and microbiology among others.

But there were mixed reviews and opinions. First, should be studied in detail where arsenic was internalized, in the genetic material or in the vacuoles (sulfobacterias are an exception because vacuoles are not common in bacteria)? It was observed that when bacteria grew in a medium rich in arsenic, acquired a larger size. It could be explained by the increased size of the vacuoles, where it accumulates intracellular structures that can not be deleted.

In any case, this experiment, expanded the horizons of knowledge.


2 responses to “The controversy of arsenic

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