Leptolyngbya

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Leptolyngbya
Systematics
Domain : Bacteria (bacteria)
Department : Cyanobacteria (Cyanobacteria)
Class : Cyanobacteria (Cyanobacteria)
Order : Synechococcales
Family : Leptolyngbyaceae
Genre : Leptolyngbya
Scientific name
Leptolyngbya
Anagnostidis and Komárek 1988

Leptolyngbya is a genus of blue-green algae (Cyanophyceae). The associated species are found in many different ecosystems. Some were found in hot springs ( thermal springs ) with temperatures in the range of 62-63 ° C; other finds come from cold deserts and the Antarctic .

features

Important features of the genus Leptolyngbya are the small diameter of the cell chains ( trichomes ) and the lack of clearly visible movement. The latter can be used to distinguish it from the very similar genus Geitlerinema .

The filamentous cells of Leptolyngbya form unbranched trichomes less than 5 μm in diameter. The individual cells are isodiametric or longer than wide. Constrictions between the cells are generally absent or flat and rarely exceed 1/8 the diameter.

The apical, d. H. Cells at the tip of the cell thread are rounded or conical (conical). Cell division occurs through a binary fission in a single plane at right angles to the longitudinal axis. There are no heterocysts . Persistence cells are not formed. For reproduction, Leptolyngbya forms so-called hormogonia , individual sections of the cell thread that peel off and grow again. With the exception of the temporarily mobile hormogonia, the trichomes are only very weak to immobile.

Many species can be infected by the bacteriophage LPP-1.

metabolism

Species of Leptolyngbya carry out oxygenic photosynthesis , during which molecular oxygen (O 2 ) is released. Some species of the genus are able to fix nitrogen (N2). During nitrogen fixation, atmospheric nitrogen (N 2 ) is converted to ammonia (NH 3 ). Ammonia can then be used for various metabolic processes. Species of Leptolyngbya (and some other blue-green algae) do not form special cells ( heterocysts ) for this. One speaks in English of "nonheterocystous cyanobacteria". The nitrogen fixation takes place here under low-oxygen conditions. Example species are Leptolyngbya boryana and Leptolyngbya foveolarum (formerly Phormidium foveolarum ).

Systematics

The genus Leptolyngbya represents a "form genus" within the phylogenetic system . DNA investigations have shown that it is a polyphyletic classification. Further phylogenetic investigations will probably lead to a division of the genus. Other polyphyletic genera of blue-green algae are z. B. Anabaena , Calothrix , Nodularia , Nostoc , Oscillatoria and Trichormus . Leptolyngbya is placed in the so-called group III within the morphological classification ( i.e. not based on genetic examinations, but on external characteristics). In English literature this is referred to as Subsection III. The genus Leptolyngbya belongs to the family Leptolyngbyaceae , which in turn belongs to the order of the Synechococcales.

Here is a list of some species (as of August 2020):

Some synonyms :

  • Leptolyngbya bijugata (Kongisser 1924) Anagnostidis and Komárek 1988 is a synonym for Nodosilinea bijugata (Kongisser 1924) Perkerson and Kovácik 2011
  • Leptolyngbya frigida (Fritsch 1912) Anagnostidis and Komárek 1988 for Pseudanabaena frigida (Fritsch 1912) Anagnostidis 2001
  • Leptolyngbya geysericola (Copeland 1936) Anagnostidis 2001 for Herpetosiphon geysericola (Copeland 1936) Lewin 1970 (Approved Lists 1980)
  • Leptolyngbya nodulosa Li and Brand 2007 for Nodosilinea nodulosa (Li and Brand 2007) Perkerson and Casamatta 2011.

The species "Leptolyngbya ohadii", described by Raanan et al. 2016, is under discussion.

ecology

The genus Leptolyngbya contains ecologically diverse blue-green algae. There are marine species, freshwater and soil bacteria in this genus. Many species of the genus Leptolyngbya are found in extreme ecosystems. These include thermal springs, lakes with high salinity and extremely cold environments.

These include B. Cold deserts . Species that live inside rocks have also been isolated here. Bacteria or fungi that occur in porous rocks are called endoliths . Bacteria that carry out photosynthesis such as Leptolyngybya have to get by with extremely little light. The small amount of photons penetrating the rock is sufficient for some types of bacteria and algae to carry out photosynthesis. They are called sciaphile ("shade-loving") species. Cyanobacteria-dominated endolithic communities in cold and arid regions consist mainly of Leptolyngbya and Chroococcidiopsis , while in hot deserts endolithic mainly Gloeocapsa and Chroococcidiopsis occur.

Leptolyngbya was u. a. found in samples within rocks in the eastern part of the Pamir Mountains . It is a cold desert, with low precipitation rates (between 50 and 150 mm per year). The average monthly air temperature is below zero between October and March. In addition, the environment is exposed to high levels of solar radiation and strong winds. The examined rock samples in the Pamir come from an altitude of 4000–4500 m. Within the rocks, actinobacteria , proteobacteria and cyanobacteria dominated. The most common genera of cyanobacteria cultivated from the samples taken were Chroococcidiopsis and Leptolyngbya . Further, uncultivated bacteria were identified by analyzing the DNA present in the rock samples. Here dominated Microcoleus , Acaryochloris , Chroococcidiopsis and Thermosynechococcus .

Other finds of the genus Leptolyngbya come from underground archaeological sites in Rome. Here too there are only weak lighting conditions.

The types Leptolyngbya erebi , L. scottii , L. glacialis , L. scottii and L. tenuis were in studies of the ground at Cierva Point , a headland of Graham Lands of the Antarctic Peninsula , isolated. These were ornithogenic soils, i.e. soils formed by guano and strong microbial activity. Most of the guano here came from penguins . Among other things, the investigation looked at the influence of global warming on the algae communities in a comparison of ornithogenic soils and mineral soils that formed without the influence of guano. It was found that the microbial communities of mineral soils are more susceptible to changes than those of ornithogenic soils due to the consequences of climate change.

The species Leptolyngbya frigida has also been found in hypolithic communities. These are bacteria and fungi that form ecosystems on the underside of rocks. The photosynthetic species occurring here used the few photons that penetrate the upper porous rock for photosynthesis. The conditions here are different from those outdoors. So water remains available here longer and the temperatures are somewhat more moderate. This applies to both desert areas and cold deserts. Hypolithic communities were z. B. investigated in the Miers Valley of the McMurdo Dry Valleys in Antarctica. During the initial colonization of such sites, cyanobacteria occur particularly during the first phase of the developmental sequence. Due to the increased nutrient enrichment as a result of the colonization, a subsequent fungal colonization takes place. Eventually, mosses can appear.

Other finds of Leptolyngbya come from the ice-free central plateau of the Byers Peninsula in the west of Livingston Island in Antarctica. Large lakes are formed here by meltwater. Microbial matting occurs within these waters. These consist of two layers. The upper one consists of dead biomass and the pigment Scytonemin secreted by blue-green algae . The pigment serves as protection against the high UV radiation that occurs there . The active part of the photosynthetic microorganisms is present in the lower, basal layer. In addition to Leptolyngbya , species of Phormidium , Anabaena , Tychonema , Synechococci , Oscillatoria and other blue layers have been identified. A comparison of samples from spring, summer and autumn showed seasonal differences in the communities.

The species Leptolyngbya foveolarum also occurs on the edge of thermal springs. Further locations are u. a. Greenhouses and ditches with polluted water.

The species “ Leptolyngbya ohadii ”, which is not yet recognized within the bacterial system, forms “biocrusts” on sand. This happens when there is very little water available. Finds of the species come from the Negev desert . For this purpose, the bacterium forms polysaccharides and can slide around within the sand. The soil is stabilized by the crust formation. This can be used to counteract the spread of desertification in arid areas.

Individual evidence

  1. ↑ a b c d e George M. Garrity (Ed.): The Archaea and the deeply branching and phototrophic Bacteria. Springer, New York 2001, ISBN 0-387-98771-1
  2. ↑ Hans Weisshaar, Helmar Almon and Peter Böger: Bioenergetics of Nitrogenase in Blue-Green Algae. I. Physiological Conditions for Nitrogenase Activity in Phormidium Foveolarum. In: Advances in Photosynthesis Research. Proceedings of the VIth International Congress on Photosynthesis , Brussels, Belgium, August 1–6, 1983 Volume 2. ISBN 978-9401763684 .
  3. ↑ Ryoma Tsujimoto, Narumi Kamiya and Yuichi Fujita: Identification of a cis-acting element in nitrogen fixation genes recognized by CnfR in the nonheterocystous nitrogen-fixing cyanobacterium Leptolyngbya boryana. In: Molecular Microbiology (2016) 101 (3), pp. 411-424
  4. ↑ Ryoma Tsujimoto, Narumi Kamiya and Yuichi Fujita: Transcriptional regulators ChlR and CnfR are essential for diazotrophic growth in nonheterocystous cyanobacteria. In: PNAS (2014), Volume 111, Issue 18, doi : 10.1073 / pnas.1323570111
  5. ↑ Jiří Komárek, Jan Kaštovský, Jan Mareš and Jeffrey R. Johansen: Taxonomic classification of cyanoprokaryotes (cyanobacterial genera), using a polyphasic approach . IN: Preslia (2014), 86: pp. 295-335. link
  6. ↑ Boon Fei Tan, Shu Harn Te, Chek Yin Boo, Karina Yew-Hoong Gin and Janelle Renee Thompson: Insights from the draft genome of the subsection V (Stigonematales) cyanobacterium Hapalosiphon sp. Strain MRB220 associated with 2-MIB production In: Standards in Genomic Sciences (2016), Volume 11, Article number 58. doi : 10.1186 / s40793-016-0175-5
  7. ^ Jean Euzéby, Aidan C. Parte: Genus Leptolyngbya. In: List of Prokaryotic names with Standing in Nomenclature (LPSN). Retrieved February 21, 2020 .
  8. ↑ a b Nataliia Khomutovska, Maja Jerzak, Iwona Kostrzewska-Szlakowska, Jan Kwiatowski, Małgorzata Suska-Malawska et al: Life in Extreme Habitats: Diversity of Endolithic Microorganisms from Cold Desert Ecosystems of Eastern Pamir. In: Polish Journal of Ecology , Volume 65, Issue 4, pp. 303-319 doi : 10.3161 / 15052249PJE2017.65.4.001
  9. ↑ E. Imre Friedmann: Endolithic Microbial Life in Hot and Cold Deserts. In: Limits of Life. Springer, Dordrecht. ISBN 978-9400990876
  10. ↑ Wong FK, Lau MC, Lacap DC, Aitchison JC, Cowan DA, Pointing SB: Endolithic microbial colonization of limestone in a high-altitude arid environment In: Appl. Microb. Ecol. (2010) 59: pp. 689-699, doi : 10.1007 / s00248-009-9607-8
  11. ^ Brian A. Whitton and Malcom Potts: The Ecology of Cyanobacteria. Kluwer Academic Publisher, ISBN 0306468557 .
  12. ↑ Patrizia Albertano and Lubomír Kováčik: Light and temperature responses of terrestrial sciaphilous strains of Leptolyngbya sp. in cross-gradient cultures. In: Algological Studies / Archives for Hydrobiology , Supplement Volumes No. 83 (1996), pp. 17-28
  13. ↑ G. González Garraza, G. Mataloni, P. and A. Fermani Vinocur: Ecology of algal communities of different soil types from Cierva Point, Antarctic Peninsula. In: Polar Biology (2011) Volume 34, pp. 339-351 doi : 10.1007 / s00300-010-0887-8
  14. ^ Cowan DA, Khan N, Pointin SB, Cary SG: Diversity of hypolithic refuge communities in the McMurdo Dry Valleys In: Antarctic Science , 2010, Volume 22, Issue 6, pp. 714-720. doi : 10.1017 / S0954102010000507
  15. ↑ Stephen B. Pointing, Yuki Chan, Donnabella C. Lacap, Maggie CY Lau, Joel A. Jurgens and Roberta L. Farrell: Highly specialized microbial diversity in hyper-arid polar desert In: PNAS (2009), November 24, Volume 106 , Issue 47, pp. 19964-19969. doi : 10.1073 / pnas.0908274106
  16. ↑ a b Rosa Margesin: Psychrophiles: From Biodiversity to Biotechnology , Springer, December 2017. ISBN 978-3319570570
  17. ↑ Jirí Komárek and Konstantinos Anagnostidis: Freshwater flora of Central Europe , Vol. 19/2: Cyanoprokaryota: Oscillatoriales. Spectrum Academic Publishing House, 2005. ISBN 3827409195
  18. ↑ a b Gianmarco Mugnai, Federico Rossi, Vincent John Martin Noah Linus Felde, Claudia Colesie, Burkhard Büdel, Stephan Peth, Aaron Kaplan and Roberto De Philippis: The potential of the cyanobacterium Leptolyngbya ohadii as inoculum for stabilizing bare sandy substrates. In: Soil Biology and Biochemistry , Volume 127, December 2018, pp. 318–328 doi : 10.1016 / j.soilbio.2018.08.007
  19. ↑ Leptolyngbya ohadii - LPSN

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