Researchers previously theorized that phosphorus, an essential building block of life, could be replaced with arsenic in basic life forms, since both elements are molecularly similar. The Mono Lake study though is the first to discover bacterium accomplishing this feat. NASA officials hope this means life can exist in areas of the universe previously ruled out because of a lack of certain elements such as phosphorus.
IU Biochemistry Chair Dr. Carl Bauer has a sample of bacterium from the highly arsenic Oregon Basalt Flats in his laboratory, and is trying to replicate the results announced by NASA.
“About six years ago we isolated a number of organisms highly resistant to arsenic. We never did anything with them other than freeze them away, we were very surprised by the Science paper. We never actually thought to look and ask the questions, ‘Are they using arsenic to substitute phosphate for their growth”
Indiana University Geology Provost’s Professor Dr. Lisa Pratt is former director of a NASA Astrobiological team searching for life below the surface of Earth and Mars. She says new life forms found on other planets may alter the perception of what life is.
“It’s very difficult to write a definition for what we recognize as life on earth. I think it will be even more problematic as we look for life that has originated and evolved on other planets.”
Dr. Bauer’s team hopes to have results from its arsenic replacement experiment in the next several months, and eventually find more organisms that can substitute one element of life for another.