''Polynucleobacter necessarius'' is a

bacterium Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were a ...

of the genus '' Polynucleobacter''.

Bacteria

These bacteria were discovered by the German microbiologist Klaus Heckmann in the cytoplasm of the ciliate ''Euplotes aediculatus'' and designated as ''Omikron'' (''Omicron'' in English literature). In 1987 ''Omikron'' / ''Omicron'' was scientifically described by Klaus Heckmann and Helmut Schmidt as the new species (and genus) ''Polynucleobacter necessarius''. Later free-living ''Polynucleobacter'' bacteria were discovered in the water columns of lakes and ponds. These planktonic, non-endosymbiontic members of the genus ''Polynucleobacter'' were initially assigned to a new subspecies of the species ''P. necessarius'' but later transferred to separate species. Since the last revision of the species, it contains exclusively obligate

endosymbionts An ''endosymbiont'' or ''endobiont'' is any organism that lives within the body or cells of another organism most often, though not always, in a mutualistic relationship. (The term endosymbiosis is from the Greek: ἔνδον ''endon'' "within" ...

dwelling in cells of the

ciliate The ciliates are a group of alveolates characterized by the presence of hair-like organelles called cilia, which are identical in structure to eukaryotic flagella, but are in general shorter and present in much larger numbers, with a differen ...

Euplotes ''Euplotes'' is a genus of ciliates in the subclass Euplotia. Species are widely distributed in marine and freshwater environments, as well as soil and moss. Most members of the genus are free-living, but two species have been recorded as comme ...

aediculatus'' and related species. This is in contrast to other species of the genus ''Polynucleobacter'', which exclusively harbour free-living bacteria dwelling in the water column of freshwater systems (lake, ponds, puddles and running waters). The

genome In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding ...

of ''P. necessarius'' has been completely

sequenced In genetics and biochemistry, sequencing means to determine the primary structure (sometimes incorrectly called the primary sequence) of an unbranched biopolymer. Sequencing results in a symbolic linear depiction known as a sequence which succi ...

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References

Burkholderiaceae Bacteria described in 1987 {{betaproteobacteria-stub

Bacteria

See also

References