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Original-"Ultramicrobacteria"

Ultramicrobacteria are

nm) in diameter. This term was first used in 1981, to refer to cocci in seawater that were less than 0.3 μm in diameter.[1] These cells have also been recovered from soil and appeared to be a mixture of Gram-positive and -negative species.[2] Many, if not all, of these small bacteria are dormant forms of larger cells that allow survival under starvation conditions.[3] In this process, cells downregulate their metabolism, stop growing and stabilize their DNA, creating dormant non-growing cells that can remain viable for many years.[4] These starvation forms may be the most common type of ultramicrobacteria in seawater.[5]

These small living bacterial cells are distinct from the purported "

nanobacteria" or "calcifying nanoparticles", which were proposed to be living organisms that were 0.1 μm in diameter.[6] These structures are now thought to be non-living,[7] and are probably precipitated particles of inorganic material.[8][9]

In an article published in Nature Communications in 2015, a team of researchers concentrated and cultured cells that had passed through 200-nanometer filters. The cells have an average volume of 0.009 cubic microns. Among the cells that were imaged using 2-D and 3-D cryogenic electron microscopy were some that were caught in the process of dividing. The genomes of the organisms were sequenced and found to be about one million base pairs in length.[10][11]

Uh0hN0 (talk) 04:17, 9 October 2017 (UTC)

Original References

  1. PMID 16345721
    .
  2. PMID 12501296
    .
  3. doi:10.1264/jsme2.2001.67
    . Retrieved 2008-06-23.
  4. PMID 8561477
    .
  5. PMID 10640668
    .
  6. PMID 17530922.{{cite journal}}: CS1 maint: unflagged free DOI (link
    )
  7. PMID 16706890
    .
  8. PMID 18282102.{{cite journal}}: CS1 maint: unflagged free DOI (link
    )
  9. PMID 18385376
    .
  10. ^ "First detailed microscopy evidence of bacteria at the lower size limit of life". ScienceDaily. Retrieved 2 March 2015.
  11. PMID 25721682
    . Retrieved 2 March 2015.

Uh0hN0 (talk) 04:18, 9 October 2017 (UTC)

Edit-"Ultramicrobacteria"

Ultramicrobacteria are bacteria that are smaller than 0.1 μm3 under all growth conditions[1][2][3]. This term was coined in 1981, to refer to cocci in seawater that were less than 0.3 μm in diameter.[4] These cells have also been recovered from soil and appeared to be a mixture of Gram-positive, Gram-negative and cell wall lacking species.[5][2] Ultramicrobacteria possess a relatively high surface area to volume ratio due to their small size, which aids in growth under oligotrophic (ie. nutrient-poor) conditions[2]. The relatively small size of ultramicrobacteria also enables parasitism of other organisms that are larger than them[2]; some ultramicrobacteria have been observed to be obligate or facultative parasites of various eukaryotes and prokaryotes[1][2]. One factor allowing ultramicrobacteria to achieve their small size seems to be genome minimization[1][2]. For example, the ultramicrobacterium P. ubique contains a 1.3 Mb genome which is seemingly devoid of extraneous genetic elements like nonworking genes, transposons or extrachromosomal elements[2]. However, genomic data from ultramicrobacteria is overall lacking[2] since the study of ultramicrobacteria, like many other prokaryotes, is hindered by difficulties in cultivating them[3].

Ultramicrobacteria are commonly confused with ultramicrocells, the latter of which are the dormant, stress-resistant forms of larger cells that form under starvation conditions[1][2][6] (cells downregulate their metabolism, stop growing and stabilize their DNA, creating ultramicrocells that can remain viable for years[1][7]). In contrast, the small size of ultramicrobacteria is not a starvation response and is consistent even under nutrient-rich conditions[3].

The term "nanobacteria" is sometimes used synonymously with ultramicrobacteria in the scientific literature[2], but ultramicrobacteria are distinct from the purported nanobacteria or "calcifying nanoparticles", which were proposed to be living organisms that were 0.1 μm in diameter.[8] These structures are now thought to be non-living,[9] and likely precipitated particles of inorganic material.[10][11]

Edit References

The newly added references are [1][2][3]

Uh0hN0 (talk) 04:01, 9 October 2017 (UTC)

  1. ^
    ISBN 9780470015902
    . Retrieved September 26, 2017.
  2. ^ a b c d e f g h i j k Duda, V; Suzina, N; Polivtseva, V; Boronin, A (2012). "Ultramicrobacteria: Formation of the Concept and Contribution of Ultramicrobacteria to Biology". Microbiology. 81 (4): 379-390.
  3. ^ a b c d Janssen, Peter; Schuhmann, Alexandra; Mörschel, Erhard; Rainey, Frederick (April 1997). "Novel anaerobic ultramicrobacteria belonging to the verrucomicrobiales lineage of bacterial descent isolated by dilution culture from anoxic rice paddy soil". Applied and Environmental Microbiology. 63 (4): 1382–1388. {{cite journal}}: |access-date= requires |url= (help)
  4. PMID 16345721
    .
  5. PMID 12501296
    .
  6. doi:10.1264/jsme2.2001.67
    . Retrieved 2008-06-23.
  7. PMID 8561477
    .
  8. PMID 17530922.{{cite journal}}: CS1 maint: unflagged free DOI (link
    )
  9. PMID 16706890
    .
  10. PMID 18282102.{{cite journal}}: CS1 maint: unflagged free DOI (link
    )
  11. PMID 18385376
    .
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