Researchers ID Earth-Birthing Enzyme
Univ. of Illinois crop sciences and Institute for Genomic Biology Prof. Gustavo Caetano-Anollés and his colleagues identified an oxygen-generating enzyme that likely was a key contributor to the rise of molecular oxygen on earth. A turning point in the history of life occurred 2 billion to 3 billion years ago with the unprecedented appearance and dramatic rise of molecular oxygen. Now researchers report they have identified an enzyme that was the first – or among the first – to generate molecular oxygen on Earth. The new findings, reported in the journal Structure, build on more than a dozen previous studies that aim to track the molecular evolution of life by looking for evidence of that history in present-day protein structures. These studies, led by Caetano-Anollés, focus on structurally and functionally distinct regions of proteins – called folds – that are part of the universal toolkit of living cells.
Read more: http://www.laboratoryequipment.com/news-Enzyme-that-Gave-Rise-of-Molecular-Oxygen-IDed-011112.aspx
Eruption early in human prehistory may have been more whimper than bang
If Hollywood’s right, the apocalypse will be brutal. Aliens, nuclear war, zombies, plague, enslavement by supersmart robots — none of them are good endings. Some archaeologists, however, believe an apocalypse has already come and gone. About 75,000 years ago, they say, a monster volcanic eruption nearly wiped out humankind, leaving behind only a few thousand people to repopulate the world.
The explosion of Indonesia’s Toba volcano was the largest eruption of the last 2 million years. The volcano coughed up some 2,000 to 3,000 cubic kilometers of ash, enough to fill almost three-quarters of the Grand Canyon. Unleashing hordes of light-blocking particles, an eruption that size should have cooled the planet and reduced rainfall, killing off plants and creating food shortages.
Archaeologists recognized in the late 1990s that the disaster might explain a population bottleneck recorded in modern people’s DNA. Read more.