Related Research Articles
A thermophile is an organism—a type of extremophile—that thrives at relatively high temperatures, between 41 and 122 °C. Many thermophiles are archaea, though some of them are bacteria and fungi. Thermophilic eubacteria are suggested to have been among the earliest bacteria.
Nitrification is the biological oxidation of ammonia to nitrate via the intermediary nitrite. Nitrification is an important step in the nitrogen cycle in soil. The process of complete nitrification may occur through separate organisms or entirely within one organism, as in comammox bacteria. The transformation of ammonia to nitrite is usually the rate limiting step of nitrification. Nitrification is an aerobic process performed by small groups of autotrophic bacteria and archaea.
The Thermoproteota are prokaryotes that have been classified as a phylum of the domain Archaea. Initially, the Thermoproteota were thought to be sulfur-dependent extremophiles but recent studies have identified characteristic Thermoproteota environmental rRNA indicating the organisms may be the most abundant archaea in the marine environment. Originally, they were separated from the other archaea based on rRNA sequences; other physiological features, such as lack of histones, have supported this division, although some crenarchaea were found to have histones. Until 2005 all cultured Thermoproteota had been thermophilic or hyperthermophilic organisms, some of which have the ability to grow at up to 113 °C. These organisms stain Gram negative and are morphologically diverse, having rod, cocci, filamentous and oddly-shaped cells. Recent evidence shows that some members of the Thermoproteota are methanogens.
The Korarchaeota is a proposed phylum within the Archaea. The name is derived from the Greek noun koros or kore, meaning young man or young woman, and the Greek adjective archaios which means ancient. They are also known as Xenarchaeota. The name is equivalent to Candidatus Korarchaeota, and they go by the name Xenarchaeota or Xenarchaea as well.
Nitrifying bacteria are chemolithotrophic organisms that include species of genera such as Nitrosomonas, Nitrosococcus, Nitrobacter, Nitrospina, Nitrospira and Nitrococcus. These bacteria get their energy from the oxidation of inorganic nitrogen compounds. Types include ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB). Many species of nitrifying bacteria have complex internal membrane systems that are the location for key enzymes in nitrification: ammonia monooxygenase, hydroxylamine oxidoreductase, and nitrite oxidoreductase.
Acidophiles or acidophilic organisms are those that thrive under highly acidic conditions. These organisms can be found in different branches of the tree of life, including Archaea, Bacteria, and Eukarya.
Cenarchaeum is a monotypic genus of archaeans in the family Cenarchaeaceae. The marine archaean Cenarchaeum symbiosum is psychrophilic and is found inhabiting marine sponges. Cenarchaeum symbiosum was initially detected as a major symbiotic microorganism living within the sponge Axinella mexicana. It has been ubiquitously detected in the world oceans at lower abundances, while in some genera of marine sponges it is one of the most abundant microbiome members. Its genome sequence and diversity has been investigated in detail finding unique metabolic products and its role in ammonia-oxidizing activities.
Nitrosopumilus is a genus of archaea. The type species, Nitrosopumilus maritimus, is an extremely common archaeon living in seawater. It is the first member of the Group 1a Nitrososphaerota to be isolated in pure culture. Gene sequences suggest that the Group 1a Nitrososphaerota are ubiquitous with the oligotrophic surface ocean and can be found in most non-coastal marine waters around the planet. It is one of the smallest living organisms at 0.2 micrometers in diameter. Cells in the species N. maritimus are shaped like peanuts and can be found both as individuals and in loose aggregates. They oxidize ammonia to nitrite and members of N. maritimus can oxidize ammonia at levels as low as 10 nanomolar, near the limit to sustain its life. Archaea in the species N. maritimus live in oxygen-depleted habitats. Oxygen needed for ammonia oxidation might be produced by novel pathway which generates oxygen and dinitrogen. N. maritimus is thus among organisms which are able to produce oxygen in dark.
Archaea is a domain of organisms. Traditionally, Archaea only included its prokaryotic members, but this since has been found to be paraphyletic, as eukaryotes are now known to have evolved from archaea. Even though the domain Archaea includes eukaryotes, the term "archaea" in English still generally refers specifically to prokaryotic members of Archaea. Archaea were initially classified as bacteria, receiving the name archaebacteria, but this term has fallen out of use.
The Nitrososphaerota are a phylum of the Archaea proposed in 2008 after the genome of Cenarchaeum symbiosum was sequenced and found to differ significantly from other members of the hyperthermophilic phylum Thermoproteota. Three described species in addition to C. symbiosum are Nitrosopumilus maritimus, Nitrososphaera viennensis, and Nitrososphaera gargensis. The phylum was proposed in 2008 based on phylogenetic data, such as the sequences of these organisms' ribosomal RNA genes, and the presence of a form of type I topoisomerase that was previously thought to be unique to the eukaryotes. This assignment was confirmed by further analysis published in 2010 that examined the genomes of the ammonia-oxidizing archaea Nitrosopumilus maritimus and Nitrososphaera gargensis, concluding that these species form a distinct lineage that includes Cenarchaeum symbiosum. The lipid crenarchaeol has been found only in Nitrososphaerota, making it a potential biomarker for the phylum. Most organisms of this lineage thus far identified are chemolithoautotrophic ammonia-oxidizers and may play important roles in biogeochemical cycles, such as the nitrogen cycle and the carbon cycle. Metagenomic sequencing indicates that they constitute ~1% of the sea surface metagenome across many sites.
Nitrososphaera is a mesophilic genus of ammonia-oxidizing Crenarchaeota. The first Nitrososphaera organism was discovered in garden soils at the University of Vienna leading to the categorization of a new genus, family, order and class of Archaea. This genus is contains three distinct species: N. viennensis, Ca. N. gargensis, and Ca N. evergladensis. Nitrososphaera are chemolithoautotrophs and have important biogeochemical roles as nitrifying organisms.
Saccharolobus solfataricus is a species of thermophilic archaeon. It was transferred from the genus Sulfolobus to the new genus Saccharolobus with the description of Saccharolobus caldissimus in 2018.
Lokiarchaeota is a proposed phylum of the Archaea. The phylum includes all members of the group previously named Deep Sea Archaeal Group, also known as Marine Benthic Group B. Lokiarchaeota is part of the superphylum Asgard containing the phyla: Lokiarchaeota, Thorarchaeota, Odinarchaeota, Heimdallarchaeota, and Helarchaeota. A phylogenetic analysis disclosed a monophyletic grouping of the Lokiarchaeota with the eukaryotes. The analysis revealed several genes with cell membrane-related functions. The presence of such genes support the hypothesis of an archaeal host for the emergence of the eukaryotes; the eocyte-like scenarios.
Nitrososphaera gargensis is a non-pathogenic, small coccus measuring 0.9 ± 0.3 μm in diameter. N. gargensis is observed in small abnormal cocci groupings and uses its archaella to move via chemotaxis. Being an Archaeon, Nitrososphaera gargensis has a cell membrane composed of crenarchaeol, its isomer, and a distinct glycerol dialkyl glycerol tetraether (GDGT), which is significant in identifying ammonia-oxidizing archaea (AOA). The organism plays a role in influencing ocean communities and food production.
James Ivor Prosser is a British microbiologist who is a Professor in Environmental Microbiology in the Institute of Biological and Environmental Sciences at the University of Aberdeen.
Asgard or Asgardarchaeota is a proposed superphylum belonging to the domain Archaea that contain eukaryotic signature proteins. It appears that the eukaryotes, the domain that contains the animals, plants, and fungi, emerged within the Asgard, in a branch containing the Heimdallarchaeota. This supports the two-domain system of classification over the three-domain system.
Crenarchaeol is a glycerol biphytanes glycerol tetraether (GDGT) biological membrane lipid. Together with archaeol, crenarcheol comprises a major component of archaeal membranes. Archaeal membranes are distinct from those of bacteria and eukaryotes because they contain isoprenoid GDGTs instead of diacyl lipids, which are found in the other domains. It has been proposed that GDGT membrane lipids are an adaptation to the high temperatures present in the environments that are home to extremophile archaea
The two-domain system is a biological classification by which all organisms in the tree of life are classified into two domains, Bacteria and Archaea. It emerged from development of knowledge of archaea diversity and challenges the widely accepted three-domain system that classifies life into Bacteria, Archaea, and Eukarya. It was preceded by the eocyte hypothesis of James A. Lake in the 1980s, which was largely superseded by the three-domain system, due to evidence at the time. Better understanding of archaea, especially of their roles in the origin of eukaryotes through symbiogenesis with bacteria, led to the revival of the eocyte hypothesis in the 2000s. The two-domain system became more widely accepted after the discovery of a large group (superphylum) of Archaea called Asgard in 2017, which evidence suggests to be the evolutionary root of eukaryotes, thereby making eukaryotes members of the domain Archaea.
Archaea, one of the three domains of life, are a highly diverse group of prokaryotes that include a number of extremophiles. One of these extremophiles has given rise to a highly complex new appendage known as the hamus. In contrast to the well-studied prokaryotic appendages pili and fimbriae, much is yet to be discovered about archaeal appendages such as hami. Appendages serve multiple functions for cells and are often involved in attachment, horizontal conjugation, and movement. The unique appendage was discovered at the same time as the unique community of archaea that produces them. Research into the structure of hami suggests their main function aids in attachment and biofilm formation. This is accomplished due to their evenly placed prickles, helical structure, and barbed end. These appendages are heat and acid resistant, aiding in the cell's ability to live in extreme environments.
References
- ↑ "Curriculum Vitae - Christa Schleper" (PDF). Archived from the original (PDF) on 2021-05-05.
- ↑ "Pioneer in archaea research (Christa Schleper)". YouTube. Retrieved 3 November 2023.
- ↑ Albers, Sonja-Verena (2018). Christa Schleper: Enthusiasm and Insight in the World of Archaea. Washington, DC: American Society for Microbiology. pp. 253–256.
- ↑ Schleper, C.; Kubo, K.; Zillig, W. (1992-08-15). "The particle SSV1 from the extremely thermophilic archaeon Sulfolobus is a virus: demonstration of infectivity and of transfection with viral DNA". Proceedings of the National Academy of Sciences. 89 (16): 7645–7649. Bibcode:1992PNAS...89.7645S. doi: 10.1073/pnas.89.16.7645 . ISSN 0027-8424. PMC 49767 . PMID 1502176.
- ↑ Schleper, Christa (1995). "Picrophilus gen. nov., fam. nov.: a novel aerobic, heterotrophic, thermoacidophilic genus and family comprising archaea capable of growth around pH 0". Journal of Bacteriology. 177 (24): 7050–7059. doi:10.1128/jb.177.24.7050-7059.1995. PMC 177581 . PMID 8522509.
- ↑ Schleper, Christa; Piihler, Gabriela; Kuhlmorgen, Brigitte; Zillig, Wolfram (June 1995). "Life at extremely low pH". Nature. 375 (6534): 741–742. Bibcode:1995Natur.375..741S. doi:10.1038/375741b0. ISSN 1476-4687. PMID 7541113. S2CID 4341809.
- ↑ Quaiser, Achim; Ochsenreiter, Torsten; Lanz, Christa; Schuster, Stephan C.; Treusch, Alexander H.; Eck, Jürgen; Schleper, Christa (2003). "Acidobacteria form a coherent but highly diverse group within the bacterial domain: evidence from environmental genomics". Molecular Microbiology. 50 (2): 563–575. doi:10.1046/j.1365-2958.2003.03707.x. ISSN 1365-2958. PMID 14617179. S2CID 25162803.
- ↑ Schleper, C; Swanson, R V; Mathur, E J; DeLong, E F (1997). "Characterization of a DNA polymerase from the uncultivated psychrophilic archaeon Cenarchaeum symbiosum". Journal of Bacteriology. 179 (24): 7803–7811. doi:10.1128/JB.179.24.7803-7811.1997. ISSN 0021-9193. PMC 179745 . PMID 9401041.
- ↑ Leininger, S.; Urich, T.; Schloter, M.; Schwark, L.; Qi, J.; Nicol, G. W.; Prosser, J. I.; Schuster, S. C.; Schleper, C. (2006). "Archaea predominate among ammonia-oxidizing prokaryotes in soils". Nature. 442 (7104): 806–809. Bibcode:2006Natur.442..806L. doi:10.1038/nature04983. ISSN 1476-4687. PMID 16915287. S2CID 4380804.
- ↑ Tourna, Maria; Stieglmeier, Michaela; Spang, Anja; Könneke, Martin; Schintlmeister, Arno; Urich, Tim; Engel, Marion; Schloter, Michael; Wagner, Michael; Richter, Andreas; Schleper, Christa (2011-05-17). "Nitrososphaera viennensis, an ammonia oxidizing archaeon from soil". Proceedings of the National Academy of Sciences. 108 (20): 8420–8425. Bibcode:2011PNAS..108.8420T. doi: 10.1073/pnas.1013488108 . ISSN 0027-8424. PMC 3100973 . PMID 21525411.
- ↑ Kerou, Melina; Offre, Pierre; Valledor, Luis; Abby, Sophie S.; Melcher, Michael; Nagler, Matthias; Weckwerth, Wolfram; Schleper, Christa (2016-12-06). "Proteomics and comparative genomics of Nitrososphaera viennensis reveal the core genome and adaptations of archaeal ammonia oxidizers". Proceedings of the National Academy of Sciences. 113 (49): E7937 –E7946. Bibcode:2016PNAS..113E7937K. doi: 10.1073/pnas.1601212113 . ISSN 0027-8424. PMC 5150414 . PMID 27864514.
- ↑ "Which genes are crucial for the energy metabolism of Archaea?". EurekAlert!. Retrieved 2021-04-26.
- ↑ Spang, Anja; Saw, Jimmy H.; Jørgensen, Steffen L.; Zaremba-Niedzwiedzka, Katarzyna; Martijn, Joran; Lind, Anders E.; van Eijk, Roel; Schleper, Christa; Guy, Lionel; Ettema, Thijs J. G. (2015). "Complex archaea that bridge the gap between prokaryotes and eukaryotes". Nature. 521 (7551): 173–179. Bibcode:2015Natur.521..173S. doi:10.1038/nature14447. ISSN 1476-4687. PMC 4444528 . PMID 25945739.
- ↑ "Lokiarchaeota and the Origin of Complex Life". Quanta Magazine. Retrieved 2021-04-26.
- ↑ US US7749366,Quaiser, Achim; Ochsenreiter, Torsten& Treusch, Alexander H.et al.,"Isolation and cloning of DNA from uncultivated organisms",published 2010-07-06, assigned to Biotechnology Research and Information Network AG
- ↑ EP 1629100,Schleper, Christa; Jonuscheit, Melanie& Eck, Jürgenet al.,"Archaeon expression system",published 2010-09-15, assigned to Biotechnology Research and Information Network AG
- ↑ WO 0018909,Swanson, Ronald V.; Feldman, Robert A.& Schleper, Christa,"Nucleic acids and proteins from Cenarchaeum symbiosum",published 2000-07-27, assigned to Diversa Corp.
- ↑ "Find an EMBO Young Investigator / EMBO Installation Grantee / EMBO Global Investigator". yip-search.embo.org. Retrieved 2021-05-05.
- ↑ "American Academy of Microbiology Fellows". Archived from the original on 2019-01-04.
- ↑ "ÖAW Mitglieder Detail". www.oeaw.ac.at. Retrieved 2021-05-05.
- ↑ "Mikrobiologin Christa Schleper erhält den diesjährigen "Austro-Nobelpreis"". Der Standard (in German). 22 June 2022. Retrieved 23 June 2022.
