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Globally distributed archaea comprising ammonia oxidizers of moderate terrestrial and marine environments are considered the most abundant archaeal organisms on Earth. Based on 16S rRNA phylogeny, initial assignment of these archaea was to the Crenarchaeota. By contrast, features of the first genome sequence from a member of this group suggested that they(More)
Genes of archaea encoding homologues of ammonia monooxygenases have been found on a widespread basis and in large amounts in almost all terrestrial and marine environments, indicating that ammonia oxidizing archaea (AOA) might play a major role in nitrification on Earth. However, only one pure isolate of this group from a marine environment has so far been(More)
The origin of the eukaryotic cell remains one of the most contentious puzzles in modern biology. Recent studies have provided support for the emergence of the eukaryotic host cell from within the archaeal domain of life, but the identity and nature of the putative archaeal ancestor remain a subject of debate. Here we describe the discovery of(More)
Rumen methanogens are major sources of anthropogenic methane emissions, and these archaea are targets in strategies aimed at reducing methane emissions. Here we show that the poorly characterised Thermoplasmata archaea in bovine rumen are methylotrophic methanogens and that they are reduced upon dietary supplementation with rapeseed oil in lactating cows.(More)
Archaea constitute a considerable fraction of the microbial biomass on Earth. Like Bacteria they have evolved a variety of energy metabolisms using organic and/or inorganic electron donors and acceptors, and many of them are able to fix carbon from inorganic sources. Archaea thus play crucial roles in the Earth's global geochemical cycles and influence(More)
The cohort of the ammonia-oxidizing archaea (AOA) of the phylum Thaumarchaeota is a diverse, widespread and functionally important group of microorganisms in many ecosystems. However, our understanding of their biology is still very rudimentary in part because all available genome sequences of this phylum are from members of the Nitrosopumilus cluster. Here(More)
Based on phylogenetic analyses and gene distribution patterns of a few complete genomes, a new distinct phylum within the Archaea, the Thaumarchaeota, has recently been proposed. Here we present analyses of six archaeal fosmid sequences derived from a microbial hot spring community in Kamchatka. The phylogenetic analysis of informational components(More)
Recent cultivation-independent studies have revealed a considerable diversity of uncultured and uncharacterized archaeal lineages. The genomic characterization of these lineages will be instrumental in order to shed light on their physiology and ecological significance and to provide an overall insight on the genomic diversity and evolution of the archaeal(More)
Insertion sequence (IS) elements are important mediators of genome plasticity and are widespread among bacterial and archaeal genomes. The 1.88 Mbp genome of the obligate intracellular amoeba symbiont Amoebophilus asiaticus contains an unusually large number of transposase genes (n = 354; 23% of all genes). The transposase genes in the A. asiaticus genome(More)
Archaeal viruses, or archaeoviruses, display a wide range of virion morphotypes. Whereas the majority of those morphotypes are unique to archaeal viruses, some are more widely distributed across different cellular domains. Tailed double-stranded DNA archaeoviruses are remarkably similar to viruses of the same morphology (order Caudovirales) that infect many(More)