Planctomycetes

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Planctomycetaceae
Systematics
Domain : Bacteria (bacteria)
Department : Planctobacteria
Class : Planctomycea
Order : Planctomycetales
Family : Planctomycetaceae
Scientific name of the  class
Planctomycea
Cavalier-Smith 2002
Scientific name of the  order
Planctomycetales
Schlesner & Stackebrandt 1987
Scientific name of the  family
Planctomycetaceae
Schlesner & Stackebrandt 1987

The Planctomycetes ( Planctomycetes ) or Planctobacteria form a well-defined division ( Divisio ), also known as the phylum , within the domain of the bacteria . One counts the class of Planctomycea (previously: Planctomycetacia) with the order of Planctomycetales and the family of Planctomycetaceae as well as the class of Phycisphaerae . Planctomycetes were discovered in the 1970s. Since then they have been found almost everywhere in the environment. Many species live aquatic, both in salt and fresh water. Some occur in hypersaline (very salty) waters, others also in the ground or in sewage sludge . The most important genera are Planctomyces , Pirellula , Isosphaera and Gemmata .

features

The Planctomycetes are unique in several ways. The cells of Planctomyces are extremely compartmentalized and often have - similar to eukaryotes - a membrane that surrounds the DNA . The cells are stalked and show a dimorphic life cycle, which is also known from Caulobacter , a type of alpha proteobacteria : A sessile cell constricts a daughter cell that forms a flagellum at the opposite pole . The swarming cell is mobile, but sheds the flagellum after a while and now in turn forms a stalk with which it attaches to a solid surface. The stalk of Planctomyces cells is structured differently than that of Caulobacter ; the two genera are not related.

Planktomycetes are also unusual because their cell wall does not have murein , but consists of a protein-rich S-layer .

The bacteria live chemoorganotrophically and are facultatively aerobic , in addition to stalked filamentous forms exist. The Isosphaera pallida species is a filamentous, sliding bacterium that occurs in hot springs at temperatures between 35 and 55 ° C.

ecology

Some Planctomycetes form associations with animals, such as B. Insects. Some unidentified planctomycetes were found in the digestive tracts of the termites Cubitermes ugandensis and Cubitermes orthognathus with the help of 16S rRNA analyzes . A planktomycete presumably of the genus Pirellula was found in the water flea Daphnia pulex . Another species was isolated from the Penaeus monodon shrimp . Planctomycetes were also found in the sponges Aplysina cavernicola and Aplysina aerophoba .

The connection between the bacteria and the host ( symbiosis or parasitism ) and what function they perform in the digestive tract is still unclear.

Furthermore, Planctomycetes could be detected on the surface of a large number of macroalgae. As part of the biofilm , they use molecules produced by the algae as nutrients. Some Planctomycete taxa have not been observed in any other habitat. Often they only make up a small proportion of the microbiome , but on the brown alga Laminaria hyperborea they make up a proportion of up to 53%.

Systematics

Analyzes of 16S rRNA gene sequences and further investigations have shown a close relationship between the Planctomycetes and the departments of Verrucomicrobia and Chlamydiae . Because of this, they together form the so-called PVC superphylum.

Genera:

swell

  1. ↑ Dirk Schmitt-Wagner, Michael W. Friedrich, Bianca Wagner, and Andreas Brune: Phylogenetic Diversity, Abundance, and Axial Distribution of Bacteria in the Intestinal Tract of Two Soil-Feeding Termites (Cubitermes spp.) In: Applied and Environmental Microbiology Vol 69, No. 10, October 2003, pp. 6007-6017 online .
  2. ↑ Andreas Brune: Symbiotic Associations Between Termites and Prokaryotes In: Martin Dworkin, Stanley Falkow, Eugene Rosenberg, Karl-Heinz Schleifer, Erko Stackebrandt (Eds.) The Prokaryotes, A Handbook of the Biology of Bacteria . Volume 1: Symbiotic Associations, Biotechnology, Applied Microbiology ISBN 0387254765 .
  3. ↑ Olga M. Lage, Joana Bondoso: Planctomycetes and macroalgae, a striking association. In: Frontiers in Microbiology. 5, 2014, doi : 10.3389 / fmicb.2014.00267 .
  4. ↑ RS Gupta, V. Bhandari, HS Naushad: Molecular Signatures for the PVC Clade (Planctomycetes, Verrucomicrobia, Chlamydiae, and Lentisphaerae) of Bacteria Provide Insights into Their Evolutionary Relationships. In: Frontiers in microbiology. Volume 3, 2012, ISSN  1664-302X , p. 327, doi : 10.3389 / fmicb.2012.00327 , PMID 23060863 , PMC 3444138 (free full text).

literature

  • Michael T. Madigan, John M. Martinko, Jack Parker: Brock - Microbiology . 11th edition. Pearson Studium, Munich 2006, ISBN 3-8274-0566-1
  • John A. Fuerst, Heather G. Gwilliam, Margaret Lindsay, Agnieszka Lichanska, Craig Belcher, Joan E. Vickers and Philip Hugenholtz: Isolation and Molecular Identification of Planctomycete Bacteria from Postlarvae of the Giant Tiger Prawn, Penaeus monodon In: Applied and Environmental Microbiology Vol. 63, No. 1, January 1997, pp. 254–262, PMC 168317 (free full text)
  • Naomi Ward, James T. Staley, John A. Fuerst, Stephen Giovannoni, Heinz Schlesner and Erko Stackebrandt: The Order Planctomycetales, including the Genera Planctomyces, Pirellula, Gemmata and Isosphaera and the Candidatus Genera Brocadia, Kuenenia and Scalindua. In: Martin Dworkin, Stanley Falkow, Eugene Rosenberg, Karl-Heinz Schleifer, Erko Stackebrandt (Eds.) The Prokaryotes, A Handbook of the Biology of Bacteria . Volume 7: Proteobacteria: Delta and Epsilon Subclasses. Deeply Rooting Bacteria .3. Edition. Springer, New York 2007, ISBN 978-0-387-25497-5 .

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