| Polynucleobacter | |
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| Genus: | Polynucleobacter Heckmann & Schmidt 1987 |
| Type species | |
| Polynucleobacter necessarius | |
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P. acidiphobus Hahn et al. 2011 Contents | |
Polynucleobacter is a genus of bacteria, originally established by Heckmann and Schmidt (1987) [1] to exclusively harbor obligate endosymbionts of ciliates belonging to the genus Euplotes .
Recently, several new Polynucleobacter species were described, [2] [3] [4] [5] [6] [7] [8] [9] [10] which all represent free-living (i.e. not host-associated) planktonic freshwater bacteria. Thus, the genus Polynucleobacter currently includes one species containing obligate endosymbionts of ciliates and nine species representing free-living planktonic strains. The type strains of the planktonic species were isolated from freshwater systems located in Antarctica, Armenia, Austria, China, Czech Republic, Finland, France, Germany, Norway, Spain, Uganda, and the United States. Currently, the genus harbors 31 species.
Free-living Poynucleobacter bacteria represent important members of bacterioplankton in freshwater systems such as lakes, ponds, and streams. [11]
Two genome projects are finished on P. necessarius strains: one project on an obligately freeliving strain isolated from an acidic freshwater pond, [12] and one project on an obligate endosymbiont of the ciliate Euplotes aediculatus. [13]
Analyses of the genome sequences resulted in the discovery of a conserved RNA motif.
Limnohabitans is a genus of bacteria established by Hahn et al. (2010). The genus contains four species which all represent planktonic bacteria dwelling in the water column of freshwater lakes, reservoirs, and streams.
Limnohabitans curvus is an aerobic, nonmotile bacterium from the genus Limnohabitans and family Comamonadaceae, which was isolated from the pelagic zone from a freshwater lake in Mondsee in Austria.
Limnohabitans parvus is a Gram-negative, aerobic, oxidase- and catalase-positive, unpigmented, short-rod-shaped, nonmotile bacterium from the genus Limnohabitans, which was isolated with Limnohabitans planktonicus from the mesoeutrophic freshwater reservoir in Římov in the Czech Republic.
Polynucleobacter necessarius is a bacterium of the genus Polynucleobacter.
Polynucleobacter acidiphobus is an aerobic, chemo-organotrophic, catalase- and oxidase-positive, nonmotile bacterium of the genus Polynucleobacter. The type strain was isolated from a rock pool which was filled with fresh water in a mountain brook in Corsica in France.
Polynucleobacter difficilis is an aerobic, catalase- and oxidase-positive, chemo-organotrophic, nonmotile, freshwater bacterium of the genus Polynucleobacter, isolated from the Lake Sevan from a depth of 60 m in Armenia.
Polynucleobacter rarus is an aerobic, chemo-organotrophic, catalase- and oxidase-positive, nonmotile bacterium of the genus Polynucleobacter, isolated from an acidic lake in Wisconsin.
Polynucleobacter asymbioticus is an aerobic, catalase- and oxidase-positive, chemo-organotrophic, nonmotile, free-living bacterium of the genus Polynucleobacter. The type strain was isolated from a small pond located in the Austrian Alps in the area of Salzburg and described as a new subspecies of Polynucleobacter necessarius in 2009. The classification of the type strain was hampered by the fact that its closest described relative represented obligate endosymbionts, i.e. P. necessarius, not available as a pure culture suitable for standard tests for delineation of prokaryotic species. Therefore, the strain was preliminarily placed in the subspecies P. necessarius subsp. asymbioticus. Later sequencing of the genome of the type strain revealed that the strain represented a novel species within the genus Polynucleobacter. Therefore, its taxonomic rank was lifted from the subspecies to the species level. Strains of P. asymbioticus dwell as planktonic organisms in acidic, humic-rich freshwater systems. Comparative genome analyses revealed that P. asymbioticus represents an atypical member of the family Burkholderiaceae regarding its small genome size and its passive lifestyle. A recent study used a collection of 37 P. asymbioticus strains isolated from various ponds located in a larger region of the Austrian Alps to gain insights in the evolution of Polynucleobacter bacteria.
Polynucleobacter wuianus is an aerobic, chemo-organotrophic, catalase- and oxidase-positive, free-living bacterium of the genus Polynucleobacter, isolated from a small pond located in the Austrian Alps in the area of Salzburg. Bacteria affiliated with this species represent planktonic bacteria (bacterioplankton) dwelling in acidic freshwater systems. The species was named after the Chinese limnologist and microbiologist Qinglong L. Wu who isolated the type strain.
Polynucleobacter yangtzensis is an aerobic, chemo-organotrophic, catalase- and oxidase-positive, sometimes motile, free-living bacterium of the genus Polynucleobacter, isolated from Yangtze River in the City of Nanjing (China). The species represents planktonic bacteria (bacterioplankton) dwelling in alkaline freshwater systems. The species name refers to the origin of the type strain.
The Silvanigrellaceae are the only family of the order Silvanigrellales, of the class Oligoflexia, of the phylum Pseudomonadota. This family currently harbors the two genera Silvanigrella and Fluviispira
Silvanigrella is a genus of the phylum Bdellovibrionota. The genus currently contains two described species: Silvanigrella aquatica and Silvanigrella paludirubra.
Rhodoluna is a Gram-positive, non-spore-forming and non-motile genus of bacteria from the family of Microbacteriaceae. The type strain of the only species Rhodoluna lacicola encodes an actinorhodopsin, which is a light-diven proton pump enabling light energy conversion, potentially resulting in a mixotrophic physiology. The type strain of R. lacicola was isolated from Lake Tai in China. The type strain MWH-Ta8 is remarkable for its very small cell size ultramicrobacterium and its small genome size of only 1.4 Mbp. The type strain has a planktonic lifestyle, that is freely floating the water column of aquatic systems. Currently, the genus Rhodoluna contains two described species.
Polynucleobacter campilacus is an aerobic, catalase- and oxidase-positive, chemo-organotrophic, nonmotile, free-living bacterium of the genus Polynucleobacter., The type strain was isolated from Lake Feldsee located in the Southern Black Forest in Germany. The species epithet "campilacus" refers to the origin of the type strain from this lake. The complete genome sequence of the strain was determined. Among the described Polynucleobacter species, P. campilacus is closest related to P. hirudinilacicola.
Polynucleobacter aenigmaticus is an aerobic, facultatively anaerobic, chemo-organotrophic, non-motile, free-living bacterium of the genus Polynucleobacter.
Polynucleobacter sphagniphilus is an aerobic, chemo-organotrophic, non-motile, free-living bacterium of the genus Polynucleobacter.
Polynucleobacter hirudinilacicola is an aerobic, chemo-organotrophic, non-motile, free-living bacterium of the genus Polynucleobacter.
Polynucleobacter paneuropaeus is an aerobic, facultatively anaerobic, chemo-organotrophic, non-motile, free-living bacterium of the genus Polynucleobacter.
Aquirufa is a genus of red-pigmented freshwater bacteria affiliated with the family of Cytophagaceae.
Aquiluna is a genus of bacteria from the order Actinomycetales. As of 2022, Aquiluna is a monotypic genus, with the only validly published species being Aquiluna borgonia. The genus was first proposed in 2009, but its type species Candiatus Aquiluna rubra was not validly published.