There are more things in heaven and earth, Horatio, Than are dreamt by most scientists

A NASA Astro-biological research has undermined some of the basic thinking regarding life forms and  biochemistry.

It has been perceived for a long time that "Carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur are the six basic building blocks of all known forms of life on Earth."

Of these "Phosphorus is part of the chemical backbone of DNA and RNA, the structures that carry genetic instructions for life" and "is a central component of the energy-carrying molecule in all cells (adenosine triphosphate) and also the phospholipids that form all cell membranes".

But a little bacteria, at the bottom of lake Mono in California, wasn't taught these accepted scientific concepts, and it turns out it works differently.

Living in an environment very low with  phosphorus and highly rich with Arsenic (which is chemically similar to phosphorus), this bacteria has been building parts of itself out of arsenic.
While for us, Arsenic disrupts metabolic pathways because chemically it behaves similarly to phosphate, for the bacteria, arsenic was used as a building block.

As detailed in NASA's news release:
"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 key issue the researchers investigated was when the microbe was grown on arsenic did the arsenic actually became incorporated into the organisms' vital biochemical machinery, such as DNA, proteins and the cell membranes. A variety of sophisticated laboratory techniques were used to determine where the arsenic was incorporated. "

Good news for everyone who likes the idea of extra-terrestrial life forms. We might not be able to drink the same beverage together, but having a biochemical alien in our midst, surely strengthens the pro-life sect, in the long debate regarding the probability of man kind ever encountering Extraterrestrial life.

And as I'm one of those pro-extra-terrestrial-life folk, this news item, adding to the june news regarding suspicious methane activity on Titan, is causing me, despite recent sad events in Israel and a stubborn flu that is visiting me, to walk around today wearing a very silly smile.

[update, end of 2012:GFAJ-1 has become a huge controversy. Original research has not been retracted, but other researchers have not been able to support it, and it is now claimed by most scientists dealing with the matter, that it is an arsenic-resistent life form (and not an arsenic-based life form). The fact that the issue is a controversy does not mean that it has been a baseless claim - only time will tell. I still remember the way other paradigm-changing researches were received. Time will tell]