When it comes to the cellular level, all organisms are divided into either prokaryotes, which have simple cells like bacteria, or eukaryotes, which have larger, more complex cells, covering the spectrum from fungi to humans. Now a new microbe has been found which appears to have a connection between both types of cell.
The key difference between the two types of cells is the complexity of their nature, with eukaryotic cells possessing a nucleus and being the building blocks to higher forms of life. Another difference is that eurkaryotes possess structures called mitochondria, which acts as “power houses” for the cells. Some theories are that mitochondria were once bacteria. The distinction is one of the most important in biological science.
These cells have been named Lokiarchaeota. The name derives from Loki’s Castle volcanic vent system. It was close to here that the microbes’ genetic material was first isolated. Loki’s castle describes a system of cold marine sediments of the Arctic Mid-Ocean Ridge. Importantly, scientists have not yet isolated the new microbe in cellular form; they have found the genetic material and have used this to model the microbial cell. Finding the cell and attempting to culture it could be difficult, given the harshness of the environmental conditions within which the microbes are thought to reside.
According to the BBC, scientists are looking for other “Loki-like” organisms in extreme environments, including hot springs in Yellowstone National Park, in the US, and New Zealand.
What is fascinating biologists, aside from the discovery of a hitherto unknown microbe, is that Lokiarchaeota possess genes that can code for proteins. These genes have only been found in eukaryotes. They types of proteins coded for include parts of the cytoskeleton (the matrix that supports cell shape and movement.)
This means that Lokiarchaeota are the closest prokaryotic organisms to the eukaryote state. It is possible, the authors of an associate research paper argue, Lokiarchaeota once shared a common ancestor with eukaryotes.
The discovery of the new microbes has been described in the journal Nature. The paper is called “Complex archaea that bridge the gap between prokaryotes and eukaryotes.”
