Refute scientific study of bacteria that could live for arsenic
Two years ago, NASA announced with much fanfare a discovery that could help us find Life on other planets: a bacterium that lived on the basis of arsenic , unlike all other forms of life on Earth, which is based on carbon, hydrogen, oxygen, nitrogen, sulfur and phosphorus.
However, after 18 months of controversy, scientists have concluded that the bacteria in question actually requires phosphorus to exist, and can not survive without it.
In 2010, the study presented in Science indicated that the bacteria Halomonadaceae GFAJ-1 could replace the phosphorus atoms of arsenic. The bacterium was discovered in Mono Lake, a very salty lake in California.
arsenic has some similarities with phosphorus, but usually toxic to living things, so the idea that a way of life could be sustained in this item off a series of doubts and criticisms about the way it was given to this discovery, with great fanfare from NASA. The Space agency funded part of the investigation, with the idea of finding different ways of life might exist elsewhere in the universe.
Several scientists were devoted to checking then study and try to replicate it without success. The journal Science published in its issue of paper two papers that confirm that although the bacteria can tolerate arsenic, your life depends on the match.
The microbiologist Rosie Redfield and his collaborators indicate that when the bacteria grow in an environment very little arsenic and phosphorus, their DNA contains no detectable arsenic compounds. In another paper, microbiologist Julia Vorholt Federal Institute of Technology in Zurich, said that the bacteria can not grow in a medium containing no phosphate and having arsenate . However, it is permitted in low phosphate media and in the presence of arsenate.
Thus, the bacterium is resistant to arsenic, but anyway dependent phosphorus.
The results indicate that the original investigation, conducted by Felisa Wolfe-Simon, samples that had contained more phosphorus than they had originally thought.
Science magazine said about it: “This new research shows that GFAJ-1 does not break long-held rules of life, contrary to the manner in which Wolfe-Simon interpreted the data of his group.”
Wolfe-Simon dropped the controversial profile, ensuring that the results of these studies “are consistent with our original paper.” The researcher noted that his paper was “suggested that the cells require phosphorus,” however, “our data suggest that a small portion of arsenate can be incorporated into biomolecules and cells, helping cells to survive in high- arsenate and phosphate very little, “he said.
According to Wolfe-Simon, this story is not yet completed. “The key question is how these cells survive in lethal concentrations of arsenic? And, where does arsenic? “
– Absence of Detectable DNA from arsenate in arsenate-Grown GFAJ-1 Cells (Science)
– GFAJ-1 Is an arsenate-Resistant, Phosphate-Dependent Organism (Science)
– Arsenic-loving bacterium Needs phosphorus after all (Nature)