A novel kingdom of parasitic archaea

Authors

Karl O. Stetter, University of Regensburg, GermanyFollow
Michael J. Hohn, University of Regensburg, GermanyFollow
Harald Huber, University of Regensburg, GermanyFollow
Reinhard Rachel, University of Regensburg, GermanyFollow
Eric Mathur, Diversa Corporation
Brian P. Hedlund, University of Nevada, Las VegasFollow
Ulrike Jahn, University of Regensburg, Germany

Editors

W.P. Inskeep and T.R. McDermott

Document Type

Chapter

Publication Date

2005

Publication Title

Geothermal Biology and Geochemistry in Yellowstone National Park

Publisher

Montana State University Publications

First page number:

249

Last page number:

259

Abstract

A nano-sized obligate symbiont obtained from a submarine hydrothermal system north of Iceland represents a novel kingdom of Archaea—the Nanoarchaeota. Cells of Nanoarchaeum equitans are only 400 nm in diameter, resulting in a cell volume of less than 1% of an Escherichia coli cell. They grow attached to the surface of a new Ignicoccus species under strict anaerobic conditions at temperatures between 75°C and 98°C. In contrast to the Ignicoccus host cell, N. equitans possesses an S-layer. The small subunit SSU rRNA gene exhibits a unique sequence characterized by base exchanges even in segments previously thought to be identical for all organisms (“universal” signatures). N. equitans harbours a genome of only 490 kb, one of the smallest genomes known so far. The analysis of its gene content reveals only very limited biosynthetic and metabolic capacities, indicating that the symbiotic relationship to Ignicoccus is parasitic. Comparison of the membrane lipids of N. equitans and its host Ignicoccus reveals that both organisms harboured qualitatively identical lipids suggesting that the N. equitans lipids are synthesized by the Ignicoccus host. Unlike many small genome bacterial parasites, N. equitans has few pseudogenes or regions of non-coding DNA. Examination of environmental DNAs from terrestrial hot springs at Yellowstone National Park; Uzon Caldera, Russia; and from an abyssal vent system at the East Pacific Rise resulted in the finding of further novel nanoarchaeotal SSU rRNA gene sequences, demonstrating great diversity and worldwide distribution of the Nanoarchaeota which had been completely overlooked, so far.

Keywords

16S rDNA; Genome sequencing; Genomes; Hot springs; Hyperthermophilic; Nanoarchaeota; Parasites; Phylogeny; Russia – Uzon Caldera; Thermophilic bacteria; Thermophilic microorganisms; United States – Yellowstone National Park

Disciplines

Bacteriology | Genetics and Genomics | Life Sciences | Microbiology

Language

English

Repository Citation

Stetter, K. O., Hohn, M. J., Huber, H., Rachel, R., Mathur, E., Hedlund, B. P., Jahn, U. (2005). A novel kingdom of parasitic archaea. In W.P. Inskeep and T.R. McDermott, Geothermal Biology and Geochemistry in Yellowstone National Park 249-259. Montana State University Publications.