Fossil find shows life on Mars possible

Scientists have found Earth's oldest fossils in Australia and say their microscopic discovery is convincing evidence that cells and bacteria were able to thrive in an oxygen-free world more than 3.4 billion years ago.

The finding suggests early life was sulphur-based - living off and metabolizing sulphur rather than oxygen for energy - and supports the idea that similar life forms could exist on other planets where oxygen levels are low or non-existent.

A natural defense mechanism used by cells in the gut to neutralize harmful toxins may lead to new ways to fight Clostridium difficile, the most common cause of hospital-acquired bacterial infections, researchers said on Sunday. Tests of an experimental compound that mimics this defense mechanism that has shown promise in the lab and in mouse studies, and the researchers say they are already planning human clinical trials. (Reuters)