Are extreme halophiles actually “bacteria”?

  title={Are extreme halophiles actually “bacteria”?},
  author={Linda J. Magrum and Kenneth R. Luehrsen and Carl R. Woese},
  journal={Journal of Molecular Evolution},
SummaryComparative cataloging of the 16S rRNA ofHalobacterium halobium indicates that the organism did not arise, as a halophilic adaptation, from some typical bacterium. Rather,H. halobium is a member of the Archaebacteria, an ancient group of organisms that are no more related to typical bacteria than they are to eucaryotes. 
Taxonomy of the family Halobacteriaceae: a paradigm for changing concepts in prokaryote systematics.
  • A. Oren
  • Biology
    International journal of systematic and evolutionary microbiology
  • 2012
An overview of the taxonomy of the family Halobacteriaceae is given, showing the impact that methods of phenotypic characterization, numerical taxonomy, chemotaxonomy and especially polar lipid analysis, 16S rRNA gene sequence comparisons, multilocus type analysis and comparative genomics have had on their classification.
Evolution of major metabolic innovations in the Precambrian
A composite phylogenetic tree depicting an overview of prokaryote evolution based on the sequences of bacterial ferredoxin, 2Fe−2S ferred toxin, 5S ribosomal RNA, andc-type cytochromes shows three zones of major metabolic innovation in the Precambrian.
Halophilic Microorganisms from Man-Made and Natural Hypersaline Environments: Physiology, Ecology, and Biotechnological Potential
Current applications of halophilic prokaryotes are presented, including bioremediation, extracellular enzymes, exopolysaccharides, and halocins, and promising developments such as S-layers and bionanotechnology are discussed.
A Short History of the Symposia on Halophilic Microorganisms: From Rehovot 1978 to Beijing 2010
This chapter provides a short history of the international symposia on all aspects of the microbiology of halophilic microorganisms held, from the first event (Rehovot, Israel, 1978) until the most
A comprehensive history of motility and Archaellation in Archaea
A historical overview on archaella and motility research in Archaea is provided, beginning with the first simple observations of motile extreme halophilic archaea a century ago up to state-of-the-art cryo-tomography of the archaellum motor complex and filament observed today.
Major players on the microbial stage: why archaea are important.
Evidence is outlined by an increasingly large and productive group of scientists that demonstrates not only that the Archaea contribute significantly to global nutrient cycling, but also that they compete successfully in 'mainstream' environments.
Phylogenetic Diversities and Community Structure of Members of the Extremely Halophilic Archaea (Order Halobacteriales) in Multiple Saline Sediment Habitats
The phylogenetic diversity and community structure of members of the halophilic Archaea (order Halobacteriales) in five distinct sediment habitats that experience various levels of salinity and salinity fluctuations are investigated, suggesting the presence of an enormous, yet-untapped supply of novel Halob bacteriales genera within the rare biosphere of various saline ecosystems.
Squalenes, phytanes and other isoprenoids as major neutral lipids of methanogenic and thermoacidophilic “archaebacteria”
The neutral lipid compositions from these bacteria, many of which exist in evironmental conditions like those described for the various evolutionary stages of the archean ecology, resemble the isoprenoid distribution isolated from ancient sediments and petroleum, and may have major implications to biological and biogeochemical evolution.


An ancient divergence among the bacteria
These two organisms are found to be sufficiently related that they can be considered members of the same genus or family and bear only slight resemblance to “typical” Procaryotic genera; such asEschericbia, Bacillus andAnacystis.
Classification of methanogenic bacteria by 16S ribosomal RNA characterization.
Comparative analysis of methanogens to constitute a distinct phylogenetic group containing two major divisions, and these organisms appear to be only distantly related to typical bacteria.
Procaryote phylogeny IV: Concerning the phylogenetic status of a photosynthetic bacterium
The 16S ribosomal RNA (30S subunit) of Rhodopseudomonas spheroides has been characterized in terms of T1 ribonuclease digestion products, and one can tentatively place the Athiorhodaceae closer to the Vibrio-Enteric group than to the Bacillaceae or Cyanophyta.
Phylogenetic structure of the prokaryotic domain: The primary kingdoms
  • C. Woese, G. Fox
  • Biology
    Proceedings of the National Academy of Sciences of the United States of America
  • 1977
A phylogenetic analysis based upon ribosomal RNA sequence characterization reveals that living systems represent one of three aboriginal lines of descent: the eubacteria, comprising all typical bacteria, the archaebacteria, and the urkaryotes, now represented in the cytoplasmic component of eukaryotic cells.
Sequence studies on 16S ribosomal RNA from a blue-green alga
SummaryThe 16S ribosomal RNA of the blue green algaAnacystis nidulans has been characterized in terms of the oligomers generated by digestion with T1 ribonuclease.A. nidulans by this criterion is
Lack of peptidoglycan in the cell walls of Methanosarcina barkeri
Neither muramic acid and glucosamine nor d-glutamic acid or other amino acids typical of peptidoglycan were found in cell walls of two strains of Methanosarcina barkeri, and the structural component of the cell wall most likely consists of an acid heteropolysaccharide, resembling that of Halococcus morrhuae.
Sulfolobus: A new genus of sulfur-oxidizing bacteria living at low pH and high temperature
Sulfolobus apparently has no close relationship with any previously described bacteria, either heterotrophic or autrotrophic, and may be an important geochemical agent in the production of sulfuric acid from sulfur in high temperature hydrothermal systems.
Comparative Cataloging of 16S Ribosomal Ribonucleic Acid: Molecular Approach to Procaryotic Systematics
A molecular approach to systematics is shown to give results in essential agreement with traditional techniques for this group of organisms, and appears well suited for higher order classification, an area which has been difficult to approach withTraditional techniques.
A Thermophilic, Acidophilic Mycoplasma Isolated from a Coal Refuse Pile
A thermophilic, acidophilic procaryote lacking a cell wall has been isolated from a coal refuse pile which had undergone self-heating and is proposed to call Thermoplasma acidophila.