Ignicoccus

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Ignicoccus
Urzwerg.jpg
Ignicoccus hospitalis (with two smaller, symbiotic Nanoarchaeum equitans)
Scientific classification
Domain:
Archaea
Phylum:
Thermoproteota
Class:
Thermoprotei
Order:
Desulfurococcales
Family:
Desulfurococcaceae
Genus:
Ignicoccus

Huber, Burggraf, Mayer, Wyschkony, Rachel & Stetter, 2000
Species
  • I. islandicus
  • I. pacificus
  • I. hospitalis

Ignicoccus is a genus of Archaea living in marine hydrothermal vents. They were discovered in Kolbeinsey Ridge north of Iceland and in the Pacific Ocean (at 9 degrees N, 104 degrees W) in 2000 (Huber et al., 2000).

Systematics[]

According to the comparisons of 16S rRNA genes, Ignicoccus represents a new, deeply branching lineage within the family of the Desulfurococcaceae (Huber et al., 2002). Three species are known, I. islandicus, I. pacificus and strain .

Cell structure[]

The archaea of the genus Ignicoccus have tiny coccoid cells with a diameter of about 2 µm, that exhibit a smooth surface, an outer membrane and no S-layer.

They have a previously unknown cell envelope structure—a cytoplasmic membrane, a periplasmic space (with a variable width of 20 to 400 nm, containing membrane-bound vesicles), and an outer membrane (approximately 10 nm wide, resembling the outer membrane of gram-negative bacteria). The latter contains numerous tightly, irregularly packed single particles (about 8 nm in diameter) and pores with a diameter of 24 nm, surrounded by tiny particles, arranged in a ring (with a diameter of 130 nm) and clusters of up to eight particles (each particle 12 nm in diameter) (Rachel et al. 2002).

The two layers of membrane previously reported is actually a type of endomembrane system consisting of cytoplasmic protutions. In I. hospitalis, these structures harbor the endosymbiotic archaeon Nanoarchaeum equitans.[1]

Physiology[]

Ignicocci live in a temperature range of 70–98 °C (optimum around 90 °C). They gain energy by reduction of elemental sulfur to hydrogen sulfide using molecular hydrogen as the electron donor (Huber et al., 2002). A unique symbiosis with (or parasitism by) Nanoarchaeum equitans has also been reported (Huber et al., 2002).

References[]

  1. ^ Heimerl T, Flechsler J, Pickl C, Heinz V, Salecker B, Zweck J, Wanner G, Geimer S, Samson RY, Bell SD, Huber H, Wirth R, Wurch L, Podar M, Rachel R (13 June 2017). "A Complex Endomembrane System in the Archaeon Ignicoccus hospitalis Tapped by Nanoarchaeum equitans". Frontiers in Microbiology. 8: 1072. doi:10.3389/fmicb.2017.01072. PMC 5468417. PMID 28659892.

Further reading[]

External links[]

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