Pores found in 'platypus of microbiology' bacterium push boundaries of evolution 1
Gemmata obscuriglobus is exceptional for its unusual morphology and for the unusual features in its genome, often considered to represent large differences in internal organization compared with most prokaryotes. G. obscuriglobus has been described as "the platypus of microbiology" 2 G. obscuriglobus is a freshwater bacterium, originally described on the basis of a single strain isolated from the littoral region near the Maroon Dam in Queensland, Australia. 3
Gemmata has a complex membrane structure, and previous studies of its 3D configuration have suggested that this bacterium has a compartmentalized cell, eukaryote-style, its genetic material encapsulated in a nucleus-like body
A bacterium dubbed the "platypus of microbiology" is even stranger than first thought, with the discovery it contains structures normally only found in more complex cells.
Bacterium Gemmata obscuriglobus originally found in Queensland in 1984. Closer inspection of its structure reveals it is the most complex bacterium ever discovered. Finding sheds light on a major problem in evolutionary cell biology
The find, by an international team led by University of Queensland researcher Emeritus Professor John Fuerst, adds to the debate about how complex cells evolved and casts doubt on long-held theories of evolution. According to the dominant theory, there are three domains of life: bacteria and archaea, which are single-celled organisms without a nucleus, and eukaryotes, organisms that include everything from yeast to us. However, the bacterium Gemmata obscuriglobus has been described as the "platypus of microbiology" because it appears to defy this theory by containing features associated with eukaryotes. These include a membrane-bounded nucleus, the ability to transport molecules such as proteins into the cell, and its ability to reproduce by a unique way of budding. Now Professor Fuerst and his team have discovered G. obscuriglobus has pore-like structures in its internal membrane that have elements structurally similar to eukaryote nuclear pores, which are found in the membrane surrounding the nucleus.
"This is a remarkable evolutionary finding since most bacteria do not possess these structures," Professor Fuerst said. He said nuclear pore complexes were important in transporting molecules between the nucleus containing the DNA and the rest of the cell contents in eukaryote organisms. "They are dotted over the surface of the membranes separating the nucleus from the rest of the cell and enable communication between the nucleus and other parts of the cell," he said. "Like the membrane-bounded nucleus, nuclear pore complexes had been thought to be restricted to eukaryotes."
New Kingdom of Life
A newly-discovered life form is so strange it doesn't fit anywhere else on the tree of life. Researchers in Nova Scotia have found a unique species that appears to be from a completely new kingdom of life, separate from plants, animals, or pretty much everything else. Hemimastigotes are so distant from all other forms of life that they likely deserve their own kingdom designation. hemimastigotes are so strange and different that they can’t fit into any of these categories—even the catch-all one—leading the researchers at Dalhousie to propose a new kingdom just for them. 4
Hemimastigophora is a novel supra-kingdom-level lineage of eukaryotes
Almost all eukaryote life forms have now been placed within one of five to eight supra-kingdom-level groups using molecular phylogenetics1,2,3,4. The ‘phylum’ Hemimastigophora is probably the most distinctive morphologically defined lineage that still awaits such a phylogenetic assignment. 5