title: Tetraether-linked membrane monolayers in Ferroplasma spp: a key to survival in acid.
abstract: Ferroplasma acidarmanus thrives in hot, extremely low pH, metal-rich solutions associated with dissolving metal sulfide ore deposits. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and thin layer chromatography analyses of F. acidarmanus membranes indicate that tetraether lipids predominate, with at least three core lipid structures. NMR measurements indicate that the cytoplasmic pH of F. acidarmanus is approximately 5.6. The optimal growth pH is approximately 1.2, and the lowest growth pH is approximately 0.0. Thus, these organisms maintain pH gradients across their membranes that approach 5 pH units. Tetraether lipids were originally thought to be specifically associated with thermophiles but are now known to be widely distributed within the archaeal domain. Our data, in combination with recently published results for thermophilic and mesothermophilic acidophilic archaea, indicate that there may be a stronger association between tetraether lipids and tolerance to acid and/or large metal ion gradients.
authors.affiliation: Department of Earth and Planetary Sciences, University of California Berkeley, McCone Hall, Berkeley, CA 94720-4767, USA. jmacalad@carleton.edu
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Macalady
authors.forename: Martha M
authors.initials: MM
authors.lastname: Vestling
authors.forename: David
authors.initials: D
authors.lastname: Baumler
authors.forename: Nick
authors.initials: N
authors.lastname: Boekelheide
authors.forename: Charles W
authors.initials: CW
authors.lastname: Kaspar
authors.forename: Jillian F
authors.initials: JF
authors.lastname: Banfield
mesh_terms: D000143:Acids / Q000378:metabolism*; D001105:Archaea / Q000378:metabolism; D002855:Chromatography, Thin Layer; D003593:Cytoplasm / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007477:Ions; D050356:Lipid Metabolism; D008055:Lipids / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D012965:Sodium Chloride / Q000737:chemistry; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013696:Temperature; D019603:Thermoplasmales / Q000235:genetics*; D013997:Time Factors
chemical_list: D000143:Acids; D007477:Ions; D008055:Lipids; D012965:Sodium Chloride