Candidatus gloeomargarita lithophora

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A Microbial Biorealm page on the genus Candidatus gloeomargarita lithophora

Classification

Higher order taxa

Domain (Bacteria); Phylum (Cyanobacteria); Class (Gloeobacteria); Order (Gloeobacterales); Genus (Candidatus Gloeomargarita)[1]

Species

Species (lithophora)

Candidatus Gloeomargarita lithophora

Description and significance

A cyanobacterium found growing in colonies at the bottom of a lake in Mexico in 2012. Actively transports strontium, barium, magnesium, and calcium into the cell from the environment and incorporates them into granules, which increase the density of the cell and help to keep the bacterium anchored at the bottom of the lake. First bacterium shown to produce internal mineralizations, as opposed to other cyanobacteria which can produce external structures as a byproduct of photosynthesis. The mechanism for this biomineralization is still unknown.[2] It is hypothesized that internal mineralization by this ancient order of cyanobacteria could help explain the lack of fossils from the early origins of cyanobacteria about 2.7 billion years ago, as evidenced by atmospheric oxygen levels, to the earliest fossil evidence of cyanobacteria about 1.2 billion years ago. [3]

Metabolism

Uses light as an energy source, but unlike other cyanobacteria does not contain thylakoids. Proton gradient forms along the plasma membrane, where phycobilisomes are attached to cytoplasmic side. Uses water as an electron donor and produces oxygen as a byproduct. [4]

Ecology

Found living in shallow water of a freshwater lake. As a cyanobacteria, is important in oxygen production and carbon fixation. The use of strontium by the cell may lead to the use of the bacterium in remediation of nuclear contamination. [2]

References

[1] ["Taxonomy Browser." NCBI. U.S. National Library of Medicine, n.d. Web. 9 Mar. 2013. <http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info>.]

[2] [E. Couradeau , K. Benzerara, E. Gérard, D. Moreira, S. Bernard, G.E. Brown Jr., and P. López-García. “An Early-Branching Microbialite Cyanobacterium Forms Intracellular Carbonates,” Science 336 (2012), 459.]

[3] [R. Riding. "A Hard Life for Cyanobacteria." Science 336 (2012): 427.]

[4] [Y. Nakamura, T. Kaneko, S. Sato, et al. "Complete genome structure of Gloeobacter violaceus PCC 7421, a cyanobacterium that lacks thylakoids". DNA Res. 10 (4): 137–45 (2003).]

Edited by Andy Nichols, student of Dr. Lisa R. Moore, University of Southern Maine, Department of Biological Sciences, http://www.usm.maine.edu/bio