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The Info List - Planctomycetes


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PLANCTOMYCETES are a phylum of aquatic bacteria and are found in samples of brackish , and marine and fresh water . They reproduce by budding . In structure, the organisms of this group are ovoid and have a holdfast , at the tip of a thin cylindrical extension from the cell body called the stalk, at the nonreproductive end that helps them to attach to each other during budding.

Cavalier-Smith has postulated that the Planctomycetes are within the clade Planctobacteria in the larger clade Gracilicutes , but this is not generally accepted.

CONTENTS

* 1 Structure * 2 Molecular Signatures * 3 Life cycle * 4 Phylogeny * 5 Taxonomy * 6 See also * 7 References * 8 External links

STRUCTURE

For a long time bacteria belonging to this group were considered to lack peptidoglycan , (also called murein) in their cell walls , which is an important heteropolymer present in most bacterial cell walls that serves as a protective component. It was thought that instead their walls were made up of glycoprotein which is rich in glutamate . Recently, however, representatives of all three clades within the Planctomycetes were found to possess peptidoglycan containing cell walls.

Planctomycetes have a distinctive morphology with the appearance of membrane -bound internal compartments, often referred to as the _paryphoplasm_ (ribosome-free space), _pirellulosome_ (ribosome-containing space) and _nucleoid_ (condensed nucleic acid region, in these species surrounded by a double membrane). Until the discovery of the Poribacteria , planctomycetes were the only bacteria known with these apparent internal compartments. Three-dimensional electron tomography reconstruction of a representative species, _ Gemmata obscuriglobus _, has yielded varying interpretations of this observation. One 2013 study found the appearance of internal compartments to be due to a densely invaginated but continuous single membrane, concluding that only the two compartments typical of Gram-negative bacteria - the cytoplasm and periplasm - are present. However, the excess membrane triples the surface area of the cell relative to its volume, which may be related to _Gemmata's_ sterol biosynthesis abilities. A 2014 study using similar methods reported confirmation of the earlier enclosed compartment hypothesis.

It has recently been shown that _ Gemmata obscuriglobus_ is able to take in large molecules via a process which in some ways resembles endocytosis , the process used by eukaryotic cells to engulf external items.

MOLECULAR SIGNATURES

Although the _Planctomycetes_ are renowned for their unusual cellular characteristics, their distinctness from all other bacteria is additionally supported by the shared presence of two conserved signature indels (CSIs). These CSIs demarcate the group from neighboring phyla within the PVC group . An additional CSI has been found that is shared by all _Planctomycetes_ species, with the exception of _Kuenenia stuttgartiensis _, which is in line with the observation that _K. stuttgartiensis_ forms a deep branch within the phylum.

A conserved signature indel has also been found to be shared by the entire PVC group , including Planctomycetes. Planctomycetes also harbours an important conserved signature protein that has been characterized to play an important housekeeping function that is exclusive to members belonging to the PVC clade.

LIFE CYCLE

The life cycle of many planctomycetes involves alternation between sessile cells and flagellated swarmer cells. The sessile cells bud to form the flagellated swarmer cells which swim for a while before settling down to attach and begin reproduction.

PHYLOGENY

See also: Bacterial taxonomy

The phylogeny based on the work of the All-Species Living Tree Project .

Phycisphaerae

_Phycisphaera mikrensis _

_Tepidisphaera mucosa _

"Planctomycetia"

_Planctopirus limnophila _

_Schlesneria paludicola _

_Gimesia maris _

_Planctomicrobium piriforme _

_Rubinisphaera brasiliensis _

_Rhodopirellula _

_R. rosea _

_R. baltica _

_R. rubra _

_R. lusitana _

_Pirellula staleyi _

_Blastopirellula _

_B. cremea _

_B. marina _

_ Gemmata obscuriglobus _

_Telmatocola sphagniphila _

_Zavarzinella formosa _

_Isosphaera pallida _

_Aquisphaera giovannonii _

_Singulisphaera _

_S. acidiphila _

_S. rosea _

TAXONOMY

The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LSPN) and the National Center for Biotechnology Information (NCBI).

* Phylum
Phylum
"PLANCTOMYCETES" Garrity & Holt 2001 emend. Ward 2011

* Class PHYCISPHAERAE Fukunaga et al. 2010

* Order TEPIDISPHAERALES Kovaleva et al. 2015

* Family TEPIDISPHAERACEAE Kovaleva et al. 2015

* Genus _Tepidisphaera _ Kovaleva et al. 2015

* Species _Tepidisphaera mucosa _ Kovaleva et al. 2015

* Order PHYCISPHAERALES Fukunaga et al. 2010

* Family PHYCISPHAERACEAE Fukunaga et al. 2010

* Genus _Algisphaera _ Yoon, Jang & Kasai 2014

* Species _Algisphaera agarilytica _ Yoon, Jang & Kasai 2014

* Genus _Phycisphaera _ Fukunaga et al. 2010

* Species _Phycisphaera mikurensis _ Fukunaga et al. 2010

* Class PLANCTOMYCETACIA Cavalier-Smith 2002

* Species ?"_Candidatus_ Nostocoida limicola III " ♠ Liu et al. 2001 * Species ?"_Candidatus_ Nostocoida acidiphila " ♠ Kulichevskaya et al. 2012

* Order "BROCADIALES " Jetten et al. 2011

* Family "BROCADIACEAE " Jetten et al. 2011

* Genus "_Candidatus_ Anammoxoglobus " Kartal et al. 2006

* Species "_Candidatus_ Anammoxoglobus propionicus " Kartal et al. 2006

* Genus "_Candidatus_ Brocadia " Jetten et al. 2001

* Species "_Candidatus_ B. anammoxidans " Jetten et al. 2001 * Species "_Candidatus_ B. brasiliensis " Araujo et al. 2011 * Species "_Candidatus_ B. caroliniensis " * Species "_Candidatus_ B. fulgida " Kartal et al. 2004 * Species "_Candidatus_ B. sinica " Hu et al. 2010

* Genus "_Candidatus_ Jettenia " Quan et al. 2008

* Species "_Candidatus_ Jettenia asiatica " Quan et al. 2008 * Species "_Candidatus_ Jettenia caeni " Ali et al. 2015 * Species "_Candidatus_ Jettenia moscovienalis " Nikolaev et al. 2015

* Genus "_Candidatus_ Kuenenia " Schmid et al. 2000

* Species "_Candidatus_ Kuenenia stuttgartiensis " Schmid et al. 2000

* Genus "_Candidatus_ Scalindua " Schmid et al. 2003

* Species "_Candidatus_ S. arabica " Woebken et al. 2008 * Species "_Candidatus_ S. marina " Van de Vossenberg et al. 2007 * Species "_Candidatus_ S. profunda " Van De Vossenberg et al. 2008 * Species "_Candidatus_ S. richardsii " Fuchsman et al. 2012 * Species "_Candidatus_ S. wagneri " Schmid et al. 2003 * Species "_Candidatus_ S. sorokinii " Kuypers et al. 2003 * Species _Candidatus_ S. brodae Schmid et al. 2003

* Order PLANCTOMYCETALES Schlesner & Stackebrandt 1987 emend. Ward 2011

* Family PLANCTOMYCETACEAE Schlesner & Stackebrandt 1987 emend. Scheuner et al. 2014

* Genus "_Bythopirellula _" ♠ Storesund & Ovreas 2013

* Species "_Bythopirellula goksoyri _" ♠ Storesund & Ovreas 2013

* Genus "_Candidatus_ Anammoximicrobium " ♠ Khramenkov et al. 2013

* Species "_Candidatus_ Anammoximicrobium moscowii " ♠ Khramenkov et al. 2013

* Genus _Aquisphaera _ Bondoso et al. 2011

* Species _Aquisphaera giovannonii _ Bondoso et al. 2011

* Genus _Blastopirellula _ Schlesner et al. 2004

* Species _B. cremea _ Lee et al. 2013 * Species _B. marina _ (Schlesner 1987) Schlesner et al. 2004

* Genus _ Gemmata _ Franzmann and Skerman 1985

* Species _ Gemmata obscuriglobus _ Franzmann & Skerman 1985

* Genus _Gimesia _ Scheuner et al. 2015

* Species _Gimesia maris _ Scheuner et al. 2015

* Genus _Paludisphaera _ Kulichevskaya et al. 2015

* Species _Paludisphaera borealis _ Kulichevskaya et al. 2015

* Genus _Pirellula _ Schlesner & Hirsch 1987 emend. Schlesner et al. 2004

* Species _Pirellula staleyi _ Schlesner & Hirsch 1987

* Genus _Planctomicrobium _ Kulichevskaya et al. 2015

* Species _Planctomicrobium piriforme _ Kulichevskaya et al. 2015

* Genus _Planctomyces _ Gimesi 1924

* Species _P. bekefii _ ♪ Gimesi 1924 (type sp.) * Species _P. guttaeformis _ ♪ (ex Hortobágyi 1965) Starr and Schmidt 1984 * Species _P. stranskae _ ♪ (ex Wawrik 1952) Starr and Schmidt 1984

* Genus _Planctopirus _ Scheuner et al. 2015

* Species _Planctopirus limnophila _ corrig. (Hirsch -webkit-column-width: 30em; column-width: 30em; list-style-type: decimal;">

* ^ Jeske, O., Schueler, M., Schumann, P., Schneider, A., Boedeker, C., Jogler, M., Bollschweiler, D., Rohde, M., Mayer, C., Engelhardt, H., Spring, S. & Jogler, C. (2015). " Planctomycetes do possess a peptidoglycan cell wall". _Nature Communications_. 6: 7116. PMC 4432640  _. PMID 25964217 . doi :10.1038/ncomms8116 . CS1 maint: Uses authors parameter (link ) * ^ van Teeseling, M.C.F., Mesman, R.J., Kuru, E., Espaillat, A., Cava, F., Brun, Y.V., VanNieuwenhze, M.S., Kartal, B & van Niftrik, L. (2015). " Anammox Planctomycetes have a peptidoglycan cell wall". Nature Communications_. 6: 6878. PMC 4432595  _. PMID 25962786 . doi :10.1038/ncomms787