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Adaptation at the Extremes of Life: Experimental Evolution with the Extremophile Archaeon Sulfolobus acidocaldarius
Published on: June 14, 2024
Ammonia-oxidising archaea--physiology, ecology and evolution.
Christa Schleper1, Graeme W Nicol
1Department of Genetics in Ecology, University of Vienna, Vienna, Austria.
Advances in Microbial Physiology
|November 17, 2010
Summary
Ammonia-oxidising archaea (AOA) are abundant, overlooked microorganisms crucial for nitrogen cycling. These archaea possess unique metabolic pathways and represent a novel phylum, Thaumarchaeota, offering insights into early life evolution.
Area of Science:
- Microbiology
- Environmental Science
- Biogeochemistry
Background:
- Nitrification, a key process in nitrogen cycling, is vital for agriculture and wastewater treatment.
- Ammonia-oxidising bacteria (AOB) were historically the primary known microorganisms responsible for the first step of nitrification.
- Recent discoveries reveal ammonia-oxidising archaea (AOA) are widespread and abundant, often outnumbering AOB.
Purpose of the Study:
- To investigate the ecological distribution and community dynamics of ammonia-oxidising archaea (AOA).
- To understand the physiological diversity and ecosystem functions of AOA.
- To explore the unique metabolic and evolutionary characteristics of AOA.
Main Methods:
- Metagenomic studies to identify AOA in various environments.
- Cultivation efforts to isolate and study AOA from marine and terrestrial hot spring environments.
- Genomic analysis of AOA to understand their metabolic pathways and evolutionary relationships.
Main Results:
- AOA are ubiquitous, abundant in diverse environments (marine, soil, sediments, hot springs), and often outnumber AOB.
- Cultivated AOA exhibit chemolithoautotrophic growth, high ammonia affinity, and can thrive in oligotrophic conditions.
- AOA possess distinct metabolisms, including copper-dependent ammonia oxidation, novel carbon fixation, and belong to the novel phylum Thaumarchaeota.
Conclusions:
- AOA are a dominant and ecologically significant group of ammonia oxidisers globally.
- Their unique physiology and metabolism highlight their crucial role in nitrogen cycling and adaptation to diverse environments.
- The discovery of Thaumarchaeota challenges existing archaeal taxonomy and provides insights into the evolution of archaea and ammonia oxidation.
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