Nitrospira moscoviensis: Difference between revisions

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Analysis of 16S rRNA places ''N. moscoviensis'' close to ''Nitrospira'' marina on a phylogenetic tree [1].
Analysis of 16S rRNA places ''N. moscoviensis'' close to ''Nitrospira'' marina on a phylogenetic tree [1].


Phylogenetic tree based on 16S ribosomal RNA.


''N. moscoviensis'' has high metabolic versatility. It is a chemolithoautotroph and a facultative aerobe. Under oxygenic conditions, it uses nitrite as its sole energy source and carbon dioxide as its sole carbon source. Organic matter does not induce mixotrophic or heterotrophic growth [1].
''N. moscoviensis'' has high metabolic versatility. It is a chemolithoautotroph and a facultative aerobe. Under oxygenic conditions, it uses nitrite as its sole energy source and carbon dioxide as its sole carbon source. Organic matter does not induce mixotrophic or heterotrophic growth [1].

Revision as of 22:27, 15 April 2018

Classification

Domain: Bacteria; Phylum: Nitrospirae; Class: Nitrospira; Order: Nitrospirales; Family: Nitrospiraceae

Species

NCBI: Nitrospira moscoviensis

Nitrospira moscoviensis

Description

Nitrospira moscoviensis is a gram-negative, non-motile, facultative aerobe. It is helical- and vibroid-shaped, but it often forms spirals. Cells are 0.9–2.2 µm × 0.2–0.4 µm in size, excrete polymers and form biofilms and grow optimally at 39°C and require a pH between 7.6-8.0 [1]. N. moscoviensis is a member of the phylum Nitrospira, which is the largest known class of nitrogen-oxidizing bacteria [2]. It the primary nitrite-oxidizer in soils, water treatment plants, and activated-sludge. N. moscoviensis also plays a significant role in the nitrogen cycle [1].

Genome Structure

N. moscoviensis has a circular chromosome [3], and its genome is 4.59 Mb in length. Its G+C content is 62% and it codes for approximately 4500 genes [4]. N. moscoviensis has been cultured although it is hard to culture, and therefore research on its genome structure has been slow [2]. It has no molecular functional marker, and detection methods have only recently been developed. Currently, the best available method is to track the gene encoding beta subunit of nitrite oxidoreductase or nxrB [5].

In 2010, the first complete genome of a Nitrospira species, Nitrospira defluvii, was sequenced. Currently, it remains the only Nitrospira species to be completely sequenced [4].

Cell Structure, Metabolism and Life Cycle

N. moscoviensis is an exclusively terrestrial, gram negative, and non-motile bacteria. Unique features of species structure are an enlarged periplasmic space, a lack of cytoplasmic membrane, and carboxysomes. It also excretes nondescript polymers to form biofilms[1][7]. When it is exposed to 7.5 mN nitrite within a mineral mixture, it takes 12 hrs to double in population size. N. moscoviensis undergoes binary fission to replicate[1].

Analysis of 16S rRNA places N. moscoviensis close to Nitrospira marina on a phylogenetic tree [1].


N. moscoviensis has high metabolic versatility. It is a chemolithoautotroph and a facultative aerobe. Under oxygenic conditions, it uses nitrite as its sole energy source and carbon dioxide as its sole carbon source. Organic matter does not induce mixotrophic or heterotrophic growth [1]. However, under anoxic conditions, N. moscoviensis uses hydrogen as an electron donor and nitrate as an electron acceptor. A solution containing soluble formate dehydrogenase allows it to use formate (CHOO-) as an electron acceptor as well. Furthermore, N. moscoviensis possesses the enzyme urease, which allows it to cleave urea into ammonia and carbon dioxide [7]. This is important for reciprocal feeding and other symbiotic relationships.

Ecology

N. moscoviensis is involved the second phase of the nitrogen cycle where it turns nitrite into nitrate. With its ability to use urea to oxidize nitrite makes it incredibly useful in wastewater treatment plants to break down urea. N. moscoviensis is usually present in the activated sludge in wastewater treatment plants. When in the presence of ammonia-oxidizing bacteria it forms a symbiotic relationship with ammonia-oxidizing bacteria, which occurs when it is used in wastewater treatment. The symbiosis is best described as reciprocal feeding. Where the N. moscoviensis provides ammonia as a product of oxidizing nitrite and the ammonia oxidizing bacteria provide the nitrite as a product in return. In aquatic environments other species of Nitrospira show evidence that this relationship has been present for a long time between the two types of bacteria [7].

References

[1] Ehrich, S., Behrens, D., Lebedeva, E., Ludwig, W., & Bock, E. (1995). A new obligately chemolithoautotrophic, nitrite-oxidizing bacterium, Nitrospira moscoviensis sp. nov. and its phylogenetic relationship. Archives of Microbiology,164(1), 16-23. [doi:https://doi.org/10.1007/BF02568729]

[2] Daims, H., Nielsen, J. L., & Schleifer, P. H. (2001). In situ characterization of Nitrospira-like nitrite-oxidizing bacteria active in wastewater treatment plants. Applied and Environmental Microbiology,67(11), 5273-5284. [1]

[3] KEGG Genome: Nitrospira moscoviensis. (n.d.). Retrieved from [2]

[4] Nitrospira moscoviensis (ID 39992). (n.d.). Retrieved from [Organism:noexp]

[5] Lücker, S., Wagner, M., Maixner, F., Pelletier, E., Koch, H., Vacherie, B., . . . Daims, H. (2010). A Nitrospira metagenome illuminates the physiology and evolution of globally important nitrite-oxidizing bacteria. PNAS,107(30), 13479-13484. [3]

[6] Maixner, F., Berry, D., Rattei, T., Koch, H., Lücker, S., Nowka, B., . . . Daims, H. (2013). NxrB encoding the beta subunit of nitrite oxidoreductase as functional and phylogenetic marker for nitrite‐oxidizing Nitrospira. Environmental Microbiology,16(10), 3055-3071. [4]

[7] Koch, H., Lücker, S., Albertsen, M., Kitzinger, K., Herbold, C., Spieck, E., . . . Daims, H. (2015). Expanded metabolic versatility of ubiquitous nitrite-oxidizing bacteria from the genus Nitrospira. PNAS,112(36), 11371-11376. [doi:https://doi.org/10.1073/pnas.1506533112]

Author

Page authored by Casey DeCaro and Ashley DeRidder, students of Prof. Jay Lennon at Indiana University.