Biochemistry / chemistry

In December 2010, the discovery of a bacterium called GFAJ-1 in Mono Lake in California caused quite a sensation. The scientists who studied it declared that it was capable of using arsenic instead of phosphorus among the basic elements of its biochemistry. Now two new studies disprove that this bacterium uses arsenic in its DNA.

The Viking 2 on Mars at Utopia Planitia in 1976 (Image JPL/NASA)

In 1976, the Viking 1 and 2 landers carried out an experiment on Mars that aimed to test the possibility that there was life on the red planet. Some chemical reactions revealed were unexpected but they weren’t regarded as evidence of the existance of life forms. The issue remained controversial and now an international team of scientists who conducted new analysis on the data from that time concluded that probably there’s life on Mars.

Enceladus and the jets of water, ice and organic materials coming from its south pole (Image NASA/JPL/Space Science Institute)

On March 27, 2012, the Cassini space proble passed at a height of just 74 km (46 miles) from the south pole of Enceladus. In this way, the probe has been able to use its Ion and Neutral Mass Spectrometer (INMS) and its Plasma Spectrometer (CAPS) to analyze the particles of the jets coming from this satellite. It was found that these jets contain organic materials and salts with a salinity level very similar to the Earth’s oceans.

Complex organic molecules found in meteorites (artist concept NASA's Goddard Space Flight Center/Chris Smith)

At NASA Goddard Space Flight Center a new research have been carried out on twelve carbon-rich meteorites finding adenine and guanine, two nucleobases which are DNA components, but also nucleobases analogs such as 2,6-diaminopurine and 6,8-diaminopurine.