Biology of archaea from a novel family Cuniculiplasmataceae (Thermoplasmata) ubiquitous in hyperacidic environments
Citations Over TimeTop 16% of 2016 papers
Abstract
The order Thermoplasmatales (Euryarchaeota) is represented by the most acidophilic organisms known so far that are poorly amenable to cultivation. Earlier culture-independent studies in Iron Mountain (California) pointed at an abundant archaeal group, dubbed 'G-plasma'. We examined the genomes and physiology of two cultured representatives of a Family Cuniculiplasmataceae, recently isolated from acidic (pH 1-1.5) sites in Spain and UK that are 16S rRNA gene sequence-identical with 'G-plasma'. Organisms had largest genomes among Thermoplasmatales (1.87-1.94 Mbp), that shared 98.7-98.8% average nucleotide identities between themselves and 'G-plasma' and exhibited a high genome conservation even within their genomic islands, despite their remote geographical localisations. Facultatively anaerobic heterotrophs, they possess an ancestral form of A-type terminal oxygen reductase from a distinct parental clade. The lack of complete pathways for biosynthesis of histidine, valine, leucine, isoleucine, lysine and proline pre-determines the reliance on external sources of amino acids and hence the lifestyle of these organisms as scavengers of proteinaceous compounds from surrounding microbial community members. In contrast to earlier metagenomics-based assumptions, isolates were S-layer-deficient, non-motile, non-methylotrophic and devoid of iron-oxidation despite the abundance of methylotrophy substrates and ferrous iron in situ, which underlines the essentiality of experimental validation of bioinformatic predictions.
Related Papers
- → Amino acid interactions in chick nutrition(1970)111 cited
- → Regulatory Role of Dietary Leucine on Plasma Branched-Chain Amino Acid Levels in Young Men(1976)45 cited
- → Valine May Be the First Limiting Branched-Chain Amino Acid in Egg Protein in Men(2003)18 cited
- → The Isoleucine, Leucine and Valine Requirements of the Chick(1946)28 cited
- → Plasma concentrations and dietary requirements of leucine, isoleucine and valine: Studies with the young chick(1974)22 cited