Gemmata obscuriglobus
| Gemmata obscuriglobus | |
|---|---|
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| Electron micrographs of representative examples illustrating G. obscuriglobus internal morphology. Scale bar = 500nm. | |
| Scientific classification | |
| Domain: | Bacteria |
| Phylum: | Planctomycetes |
| Class: | Planctomycetacia |
| Order: | Planctomycetales |
| Family: | Planctomycetaceae |
| Genus: | Gemmata |
| Species: | G. obscuriglobus |
| Binomial name | |
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Gemmata obscuriglobus Franzmann and Skerman, 1985 |
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Gemmata obscuriglobus is a Gram-negative, aerobic, heterotrophic, motile bacterium of the phylum Planctomycetes, first described in 1984 as the only described species in the genus Gemmata. It 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".
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.
G. obscuriglobus is a large, roughly spherical bacterium with a cell diameter of 1–2μm. It is motile and possesses multiple flagella per cell (that is, it is multitrichous). Dense, compact DNA and a deeply invaginated membrane are characteristics of the species.
Among the most notable features of G. obscuriglobus is its highly complex and morphologically distinctive cell membrane system, including deep invaginations of its membrane that historically have been described as closed internal membranes that may surround the bacterium's DNA by analogy to a eukaryotic cell nucleus. The concept of membrane-bound genetic material has been described as a "cell plan" unique to a proposed superphylum composed of the Planctomycetes, Verrucomicrobia, and Chlamydiae (PVC) and distinct from the rest of the Gram-negative bacteria. The question of whether G. obscuriglobus and other members of the PVC group possess closed internal membranes and therefore have a unique "cell plan" is considered important in understanding the evolution of membrane-bound compartments, which are often considered a distinguishing feature between eukaryotes and prokaryotes; the lineage that gave rise to the PVC superphylum is speculated to be related to an "intermediate" state between prokaryotes and eukaryotes. The question of how the PVC superfamily membranes are organized and how they relate to eukaryotes is an active and controversial area of research.
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