Mitochondria-free animals live in oxygen-starved basin
Researchers have discovered three species of Loricifera living in an oxygen-starved basin at the bottom of the Mediterranean Sea. Loricifera are marine sediment-dwelling animals consisting of a head, mouth, digestive system and outer shell called a lorica.
The unnamed Loricifera species appears to have a large number of hydrogenosome-like organelles. Mitochondria supply energy to eukaryotic cells which are essential to most living organisms. While mitochondria rely on oxygen to function, Roberto Danovaro from the Polytechnic University of Marche in Ancona, Italy and his colleagues suggest the hydrogenosome-like organelles play a similar role but use hydrogen instead. Hydrogenosomes are in many ways the hydrogen-based equivalent of mitochondria in some single-celled organisms, such as fungi.
While the researchers had located multi-celled animals in other anoxic environments, this is the first discovery of oxygen-independent, mitochondria-less metazoa—multi-celled animals—living in this particular basin. And these are the first that researchers believe are permanent residents of an oxygen-starved environment. In a Nature article today, Danovaro described the exploration of biodiversity in this anoxic environment like “going to the Moon to collect rocks.”
Roberto Danovaro, Antonio Dell’Anno, Antonio Pusceddu, Cristina Gambi, Iben Heiner, & Reinhardt Mobjerg Kristensen (2010). The first metazoa living in permanently anoxic conditions BMC Biology, 8 (3)