Thursday, 9 December 2010

Grow and prosper with Arsenic?

New Rochelle, NY, December 7, 2010—NASA-funded research has uncovered a new life form on Earth, a microorganism that can not only survive but can thrive and reproduce by metabolizing arsenic, a chemical that is highly toxic for most other earthly organisms. This finding will revolutionize the field of astrobiology—the study of the origins, evolution, distribution, and future of life in the universe.

The new form of life, discovered in Mono Lake in California, a harsh environment with high salt, pH, and arsenic levels, represents a new strain of a common family of bacteria. It is able to substitute arsenic for phosphorus, one of the six basic building blocks of all forms of life on Earth. The microbe utilizes arsenic in place of phosphorus to build critical cell components, including its DNA, proteins, cell membranes, and energy-producing machinery.

“The discovery of a bacterium capable of substituting arsenate for phosphate in essential biomolecules impacts astrobiology in a number of ways,” says Sherry L. Cady, Professor in the Department of Geology at Portland State University. “It is quite astonishing to learn that this life form has the capacity to function in a way no other known life form can. The directed search for this biochemistry, revealed by routine methods, was essential to this find and an important lesson. Astrobiology search strategies for environments that harbor microbes with such biochemistries now increase in a way few have predicted.

However, one external researcher expressed “lingering concerns that the arsenic is simply concentrated in the bacterial cell’s extensive vacuoles and not incorporated into its biochemistry, and another said that the claim of bacteria subbing arsenic for phosphorous “is, in my opinion, not established by this work.”