A comprehensive study into the molecular methodology and molecular biology of methanogenic Archaea

Lange, Marianne; Ahring, Birgitte K.

doi:10.1111/j.1574-6976.2001.tb00591.x

Cited by 60 publications

(34 citation statements)

References 146 publications

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“…Methanosarcina and Methanococcus species are facultative autotrophs that readily take up amino acids, and are therefore compatible with auxotrophic markers 74 . To enable full exploitation of auxotrophic markers, it is best if the organism can be grown on chemically defined (minimal) medium, as is the case for P. abyssi 75 ,…”

Section: Transformationmentioning

confidence: 99%

Archaeal genetics — the third way

2005

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| For decades, archaea were misclassified as bacteria on account of their prokaryotic morphology. Molecular phylogeny eventually revealed that archaea, like bacteria and eukaryotes, are a fundamentally distinct domain of life. Genome analyses have confirmed that archaea share many features with eukaryotes, particularly in information processing, and therefore can serve as streamlined models for understanding eukaryotic biology. Biochemists and structural biologists have embraced the study of archaea but geneticists have been more wary, despite the fact that genetic techniques for archaea are quite sophisticated. It is high time for geneticists to start asking fundamental questions about our distant relatives.

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Section: Transformationmentioning

confidence: 99%

Archaeal genetics — the third way

2005

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“…While genetic methodology has been developed for methanogenic archaea (19,34) and extremely halophilic archaea (24,34), comparable to those of their bacterial counterparts, manipulative strategies for the hyperthermophilic archaea are still at an early stage. With respect to the genus Sulfolobus in the kingdom Crenarchaeota, various genetic elements have been identified (44), and natural gene transfer via conjugation (26,31) or virus infection (32) has been observed.…”

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Targeted Gene Disruption by Homologous Recombination in the Hyperthermophilic ArchaeonThermococcus kodakaraensisKOD1

et al. 2003

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In contrast to the high accumulation in sequence data for hyperthermophilic archaea, methodology for genetically manipulating these strains is still at an early stage. This study aimed to develop a gene disruption system for the hyperthermophilic euryarchaeon Thermococcus kodakaraensis KOD1. Uracil-auxotrophic mutants with mutations in the orotidine-5-monophosphate decarboxylase gene (pyrF) were isolated by positive selection using 5-fluoroorotic acid (5-FOA) and used as hosts for further transformation experiments. We then attempted targeted disruption of the trpE locus in the host strain by homologous recombination, as disruption of trpE was expected to result in tryptophan auxotrophy, an easily detectable phenotype. A disruption vector harboring the pyrF marker within trpE was constructed for double-crossover recombination. The host cells were transformed with the exogenous DNA using the CaCl 2 method, and several transformants could be selected based on genetic complementation. Genotypic and phenotypic analyses of a transformant revealed the unique occurrence of targeted disruption, as well as a phenotypic change of auxotrophy from uracil to tryptophan caused by integration of the wild-type pyrF into the host chromosome at trpE. As with the circular plasmid, gene disruption with linear DNA was also possible when the homologous regions were relatively long. Shortening these regions led to predominant recombination between the pyrF marker in the exogenous DNA and the mutated allele on the host chromosome. In contrast, we could not obtain trpE disruptants by insertional inactivation using a vector designed for single-crossover recombination. The gene targeting system developed in this study provides a long-needed tool in the research on hyperthermophilic archaea and will open the way to a systematic, genetic approach for the elucidation of unknown gene function in these organisms.Among the living organisms, hyperthermophiles belonging to the third domain of life, Archaea, are attractive subjects of research from various standpoints. Many efforts to understand the strategies for adaptation to extremely high temperature environments have revealed numerous physiologically intriguing and unique properties of hyperthermophilic archaea (30,36,37). They have also attracted attention from an industrial point of view as potential resources for highly thermostable enzymes (3,23,40).Along with the classical biochemistry and molecular cloning of structural genes, complete genome analyses in recent years have provided a new means of understanding the hyperthermophilic archaea. So far, entire genome sequences of 16 archaeal strains, including 10 hyperthermophiles, have been determined. This has revealed that genomes of hyperthermophilic archaea are rather small, and the small number of genes makes them ideal targets for studying the basic principles and evolution of life.In spite of the many attractive aspects of hyperthermophilic archaea, progress of research on these organisms has been constantly hampered by the limitation...

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“…have been isolated from cold habitats (Franzmann et al 1992(Franzmann et al , 1997Simankova et al 2003). Although the metabolism of methanogenic archaea has been studied in different environments (Ni and Boone 1998;Garcia et al 2000;Eicher 2001;Lange and Ahring 2001), only a few studies have focussed on the ecology of the methanogenic archaea in permafrost ecosystems (Vishnivetskaya et al 2000;Høj et al 2005). Studies have shown that methanogenic archaea from Siberian permafrost are well adapted to osmotic stress and are also highly resistant to inactivation by desiccation, radiation, extremely low temperatures (Morozova and Wagner, data under processing) and high oxygen partial pressure (Wagner et al 1999).…”

Section: Introductionmentioning

confidence: 99%

Survival of Methanogenic Archaea from Siberian Permafrost under Simulated Martian Thermal Conditions

Morozova

Möhlmann

Wagner

2006

Orig Life Evol Biosph

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Methanogenic archaea from Siberian permafrost complementary to the already well-studied methanogens from non-permafrost habitats were exposed to simulated Martian conditions. After 22 days of exposure to thermo-physical conditions at Martian low-and midlatitudes up to 90% of methanogenic archaea from Siberian permafrost survived in pure cultures as well as in environmental samples. In contrast, only 0.3% -5.8% of reference organisms from non-permafrost habitats survived at these conditions. This suggests that methanogens from terrestrial permafrost seem to be remarkably resistant to Martian conditions. Our data also suggest that in scenario of subsurface lithoautotrophic life on Mars, methanogenic archaea from Siberian permafrost could be used as appropriate candidates for the microbial life on Mars.

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A comprehensive study into the molecular methodology and molecular biology of methanogenic Archaea

Cited by 60 publications

References 146 publications

Archaeal genetics — the third way

Archaeal genetics — the third way

Targeted Gene Disruption by Homologous Recombination in the Hyperthermophilic ArchaeonThermococcus kodakaraensisKOD1

Survival of Methanogenic Archaea from Siberian Permafrost under Simulated Martian Thermal Conditions

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