NASA researchers discover arsenic-based life form on Earth

WASHINGTON - A new research has changed the fundamental knowledge about what comprises all known life on Earth.

NASA researchers conducting tests in the harsh environment of Mono Lake in California have discovered the first known micro-organism on Earth able to thrive and reproduce using the toxic chemical arsenic. The micro-organism substitutes arsenic for phosphorus in its cell components.

“The definition of life has just expanded. As we pursue our efforts to seek signs of life in the solar system, we have to think more broadly, more diversely and consider life as we do not know it,” said Ed Weiler, NASA’s associate administrator.

This finding of an alternative biochemistry makeup will alter biology textbooks and expand the scope of the search for life beyond Earth.

Carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur are the six basic building blocks of all known forms of life on Earth. Phosphorus is part of the chemical backbone of DNA and RNA, the structures that carry genetic instructions for life, and is considered an essential element for all living cells.

Arsenic, which is chemically similar to phosphorus, is poisonous for most life on Earth. Arsenic disrupts metabolic pathways because chemically it behaves similarly to phosphate.

“We know that some microbes can breathe arsenic, but what we’ve found is a microbe doing something new-building parts of itself out of arsenic,” said Felisa Wolfe-Simon, a NASA astrobiology research fellow in residence at the U.S. Geological Survey.

The newly discovered microbe, strain GFAJ-1, is a member of a common group of bacteria, the Gammaproteobacteria.

In the laboratory, the researchers successfully grew microbes from the lake on a diet that was very lean on phosphorus, but included generous helpings of arsenic.

When researchers removed the phosphorus and replaced it with arsenic the microbes continued to grow. Subsequent analyses indicated that the arsenic was being used to produce the building blocks of new GFAJ-1 cells.

The research was published in the Science Express. (ANI)