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Related Experiment Video

Updated: Jun 1, 2026

Knee Arthrocentesis in Adults

Knee Arthrocentesis in Adults

Published on: February 25, 2022

Editor's Note.

Bruce Alberts¹

¹Editor-in-Chief, Science, American Association for the Advancement of Science, 1200 New York Avenue NW, Washington, DC 20005, USA.

Science (New York, N.Y.)

|May 31, 2011

Summary

This summary is machine-generated.

A microbe was discovered that can substitute arsenic for phosphorus in its biomolecules. This finding challenges the fundamental definition of life and its essential chemical requirements.

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Last Updated: Jun 1, 2026

Knee Arthrocentesis in Adults

Knee Arthrocentesis in Adults

Published on: February 25, 2022

Area of Science:

Microbiology
Biochemistry
Astrobiology

Background:

All known life uses phosphorus in essential biomolecules like DNA and ATP.
The search for extraterrestrial life often relies on identifying life's fundamental chemical requirements.

Purpose of the Study:

To investigate whether any known organism could incorporate arsenic into its biomolecules.
To challenge the established biochemical definition of life.

Main Methods:

Culturing bacteria in environments with high arsenic and low phosphorus concentrations.
Analyzing the bacteria's cellular components using advanced spectroscopic techniques.

Main Results:

The bacterium GFAJ-1 was shown to incorporate arsenate into its DNA, RNA, and proteins.
Evidence suggested arsenic replaced phosphorus in key cellular structures.

Conclusions:

The study suggested a potential expansion of the known biochemical requirements for life.
The findings opened new avenues for astrobiological research and the search for alternative life forms.