Melainabacteria

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Melainabacteria
cells.

Scale bar, 5.0 μm.

Scientific classification Edit this classification
Domain: Bacteria
Clade: Cyanobacteria-Melainabacteria group
Phylum: Melainabacteria
Di Rienzi et al. 2013[1]
Orders
  • "Caenarcaniphilales"
  • "Gastranaerophilales"
  • "Obscuribacterales"
  • "Vampirovibrionales"
Synonyms
  • "Melainobacteriota" corrig. Di Rienzi et al. 2013

Melainabacteria is a phylum related to Cyanobacteria. Organisms belonging to this phylum have been found in the human gut and various aquatic habitats such as groundwater. By analyzing genomes of Melainabacteria, predictions are possible about the cell structure and metabolic abilities. The bacterial cell is similar to cyanobacteria in being surrounded by two membranes.[2] It differs from cyanobacteria in its ability to move by flagella (like gram-negative flagella), though some members (e.g. Gastranaerophilales) lack flagella.[2] Melainabacteria are not able to perform photosynthesis, but obtain energy by fermentation.

Phylogeny

16S rRNA based
LTP_12_2021[3][4][5]
120 single copy marker proteins based GTDB 08-RS214[6][7][8]
Terrabacteria

"Cyanobacteriota"

"Melainabacteria"

Vampirovibrio

Terrabacteria

"Margulisbacteria"

"Cyanobacteriota"

"

Sericytochromatia
"

Cyanobacteria

"Melainabacteria"
"Caenarcanales"

"Ca. Caenarcanum"

"Obscuribacterales"

"Ca. Obscuribacter"

"Vampirovibrionales"

Vampirovibrio

"Gastranaerophilales"
CAJFVJ01

"Ca. Adamsella"

RUG14156

"Ca. Galligastranaerophilus"

"Gastranaerophilaceae"

Classification

Ecological Niche

Melainabacteria can be found in a range of environments, including soil, water, and animal habitats. They can be often be found in the gut of humans and in the respiratory tract, oral environments, and skin surface, though rarely. Melainabacteria is often found in natural environments such as groundwater aquifers and lake sediment, as well as soil and bioreactors.[9] Melainabacteria are also found in the aphotic zone of aquatic environments such as lake sediment and aquifers.[9] Cyanobacteria bloom in freshwater systems as a result of excess nutrients and high temperatures, resulting in a scum on the water surface that resembles spilled paint.[9] Because Melainabacteria and Cyanobacteria are related, it has raised concern because Melainabacteria thrive in groundwater systems. The genomes of Melainabacteria were found to be bigger when found in aquifer systems and algal cultivation ponds than when in the mammalian gut environment.[9]

Origin

The Great Oxygenation Event (GOE) that occurred 2.4 billion years ago altered the course of life on Earth forever by increasing the abundance of oxygen in the atmosphere. [10][11]Bacteria that existed before the GEO did not rely on the presence of oxygen as a source for metabolism, such as the billion-year-old Cyanobacteria. Melainabacteria is a close relative to Cyanobacteria, though Melainabacteria diverged and do not photosynthesize.[12] Cyanobacteria produced atmospheric oxygen and supported the development of early plant cells.[13]

Genome

The genomes of Melainabacteria organisms isolated from ground water indicate that the organism has the capacity to fix nitrogen. Melainabacteria lack linked electron transport chains but have multiple methods to generate a membrane potential which can then produce

K vitamins, which suggests that these bacteria are beneficial to their host because they are consumed along with plant fibers.[2][14]

Animal Habitats

Melainabacteria have been found to potentially play a role in digesting fiber in the human gut,

References

  1. ^ Di Rienzi, S.C., Sharon, I., Wrighton, K.C., Koren, O., Hug, L.A., Thomas, B.C., Goodrich, J.K., Bell, J.T., Spector, T.D., Banfield, J.F., and Ley, R.E. "The human gut and groundwater harbor non-photosynthetic bacteria belonging to a new candidate phylum sibling to Cyanobacteria." eLife (2013) 2:e01102.
  2. ^
    PMID 24137540
    .
  3. ^ "The LTP". Retrieved 23 February 2021.
  4. ^ "LTP_all tree in newick format". Retrieved 23 February 2021.
  5. ^ "LTP_12_2021 Release Notes" (PDF). Retrieved 23 February 2021.
  6. ^ "GTDB release 08-RS214". Genome Taxonomy Database. Retrieved 10 May 2023.
  7. ^ "bac120_r214.sp_label". Genome Taxonomy Database. Retrieved 10 May 2023.
  8. ^ "Taxon History". Genome Taxonomy Database. Retrieved 10 May 2023.
  9. ^
    PMID 35454968
    .
  10. .
  11. .
  12. ^ Biello, David. "The Origin of Oxygen in Earth's Atmosphere". Scientific American. Retrieved 2022-10-03.
  13. ^ a b "New bacteria found in human gut". Cornell Chronicle. Retrieved 2022-10-03.
  14. PMID 24709563
    .

External links