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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 they can be bacteria. Thermophilic eubacteria are suggested to have been among the earliest bacteria.
A mesophile is an organism that grows best in moderate temperature, neither too hot nor too cold, with an optimum growth range from 20 to 45 °C. The term is mainly applied to microorganisms. Organisms that prefer extreme environments are known as extremophiles. Mesophiles have diverse classifications, belonging to two domains: Bacteria, Archaea, and to kingdom Fungi of domain Eucarya. Mesophiles belonging to the domain Bacteria can either be gram-positive or gram-negative. Oxygen requirements for mesophiles can be aerobic or anaerobic. There are three basic shapes of mesophiles: coccus, bacillus, and spiral.
In biochemistry, chemosynthesis is the biological conversion of one or more carbon-containing molecules and nutrients into organic matter using the oxidation of inorganic compounds or ferrous ions as a source of energy, rather than sunlight, as in photosynthesis. Chemoautotrophs, organisms that obtain carbon from carbon dioxide through chemosynthesis, are phylogenetically diverse. Groups that include conspicuous or biogeochemically-important taxa include the sulfur-oxidizing gamma and epsilon proteobacteria, the Aquificae, the methanogenic archaea and the neutrophilic iron-oxidizing bacteria.
A hydrothermal vent is a fissure on the seafloor from which geothermally heated water discharges. Hydrothermal vents are commonly found near volcanically active places, areas where tectonic plates are moving apart at spreading centers, ocean basins, and hotspots. Hydrothermal deposits are rocks and mineral ore deposits formed by the action of hydrothermal vents.
Aquifex is a bacterial genus, belonging to phylum Aquificota. There is one species of Aquifex with a validly published name – A. pyrophilus – but "A. aeolicus" is sometimes considered as species though it has no standing as a name given it has not been validly or effectively published. Aquifex spp. are extreme thermophiles, growing best at temperature of 85 °C to 95 °C. They are members of the Bacteria as opposed to the other inhabitants of extreme environments, the Archaea.
"Aquifex aeolicus" is a chemolithoautotrophic, Gram-negative, motile, hyperthermophilic bacterium. "A. aeolicus" is generally rod-shaped with an approximate length of 2.0-6.0μm and a diameter of 0.4-0.5μm. "A. aeolicus" is neither validly nor effectively published and, having no standing in nomenclature, should be styled in quotation marks. It is one of a handful of species in the Aquificota phylum, an unusual group of thermophilic bacteria that are thought to be some of the oldest species of bacteria, related to filamentous bacteria first observed at the turn of the century. "A. aeolicus" is also believed to be one of the earliest diverging species of thermophilic bacteria. "A. aeolicus" grows best in water between 85 °C and 95 °C, and can be found near underwater volcanoes or hot springs. It requires oxygen to survive but has been found to grow optimally under microaerophilic conditions. Due to its high stability against high temperature and lack of oxygen, "A. aeolicus" is a good candidate for biotechnological applications as it is believed to have potential to be used as hydrogenases in an attractive H2/O2 biofuel cell, replacing chemical catalysts. This can be useful for improving industrial processes.
Sulfur-reducing bacteria are microorganisms able to reduce elemental sulfur (S0) to hydrogen sulfide (H2S). These microbes use inorganic sulfur compounds as electron acceptors to sustain several activities such as respiration, conserving energy and growth, in absence of oxygen. The final product or these processes, sulfide, has a considerable influence on the chemistry of the environment and, in addition, is used as electron donor for a large variety of microbial metabolisms. Several types of bacteria and many non-methanogenic archaea can reduce sulfur. Microbial sulfur reduction was already shown in early studies, which highlighted the first proof of S0 reduction in a vibrioid bacterium from mud, with sulfur as electron acceptor and H2 as electron donor. The first pure cultured species of sulfur-reducing bacteria, Desulfuromonas acetoxidans, was discovered in 1976 and described by Pfennig Norbert and Biebel Hanno as an anaerobic sulfur-reducing and acetate-oxidizing bacterium, not able to reduce sulfate. Only few taxa are true sulfur-reducing bacteria, using sulfur reduction as the only or main catabolic reaction. Normally, they couple this reaction with the oxidation of acetate, succinate or other organic compounds. In general, sulfate-reducing bacteria are able to use both sulfate and elemental sulfur as electron acceptors. Thanks to its abundancy and thermodynamic stability, sulfate is the most studied electron acceptor for anaerobic respiration that involves sulfur compounds. Elemental sulfur, however, is very abundant and important, especially in deep-sea hydrothermal vents, hot springs and other extreme environments, making its isolation more difficult. Some bacteria – such as Proteus, Campylobacter, Pseudomonas and Salmonella – have the ability to reduce sulfur, but can also use oxygen and other terminal electron acceptors.
In taxonomy, Staphylothermus is a genus of the Desulfurococcaceae.[1]
Sulfurimonas is a bacterial genus within the class of Campylobacterota, known for reducing nitrate, oxidizing both sulfur and hydrogen, and containing Group IV hydrogenases. This genus consists of four species: Sulfurimonas autorophica, Sulfurimonas denitrificans, Sulfurimonas gotlandica, and Sulfurimonas paralvinellae. The genus' name is derived from "sulfur" in Latin and "monas" from Greek, together meaning a “sulfur-oxidizing rod”. The size of the bacteria varies between about 1.5-2.5 μm in length and 0.5-1.0 μm in width. Members of the genus Sulfurimonas are found in a variety of different environments which include deep sea-vents, marine sediments, and terrestrial habitats. Their ability to survive in extreme conditions is attributed to multiple copies of one enzyme. Phylogenetic analysis suggests that members of the genus Sulfurimonas have limited dispersal ability and its speciation was affected by geographical isolation rather than hydrothermal composition. Deep ocean currents affect the dispersal of Sulfurimonas spp., influencing its speciation. As shown in the MLSA report of deep-sea hydrothermal vents Campylobacterota, Sulfurimonas has a higher dispersal capability compared with deep sea hydrothermal vent thermophiles, indicating allopatric speciation.
Thermoplasma volcanium is a moderate thermoacidophilic archaea isolated from acidic hydrothermal vents and solfatara fields. It contains no cell wall and is motile. It is a facultative anaerobic chemoorganoheterotroph. No previous phylogenetic classifications have been made for this organism. Thermoplasma volcanium reproduces asexually via binary fission and is nonpathogenic.
Thermotoga elfii is a rod-shaped, glucose-fermenting bacterium. The type strain of T. elfii is SEBR 6459T. The genus Thermotoga was originally thought to be strictly found surrounding submarine hydrothermal vents, but this organism was subsequently isolated in African oil wells in 1995. A protective outer sheath allows this microbe to be thermophilic. This organism cannot function in the presence of oxygen making it strictly anaerobic. Some research proposes that the thiosulfate-reducing qualities in this organism could lead to decreased bio-corrosion in oil equipment in industrial settings.
This article discusses the Unique properties of hyperthermophilic archaea. Hyperthermophiles are organisms that can live at temperatures ranging between 70 and 125 °C. They have been the subject of intense study since their discovery in 1977 in the Galapagos Rift. It was thought impossible for life to exist at temperatures as great as 100 °C until Pyrolobus fumarii was discovered in 1997. P. fumarii is a unicellular organism from the domain Archaea living in the hydrothermal vents in black smokers along the Mid-Atlantic Ridge. These organisms can live at 106 °C at a pH of 5.5. To get energy from their environment these organisms are facultatively aerobic obligate chemolithoautotrophs, meaning these organisms build biomolecules by harvesting carbon dioxide (CO2) from their environment by using hydrogen (H2) as the primary electron donor and nitrate (NO3−) as the primary electron acceptor. These organisms can even survive the autoclave, which is a machine designed to kill organisms through high temperature and pressure. Because hyperthermophiles live in such hot environments, they must have DNA, membrane, and enzyme modifications that help them withstand intense thermal energy. Such modifications are currently being studied to better understand what allows an organism or protein to survive such harsh conditions. By learning what lets these organisms survive such harsh conditions, researchers can better synthesize molecules for industry that are harder to denature.
Persephonella guaymasensis is a thermophilic, hydrogen-oxidizing microaerophile first isolated from a deep-sea hydrothermal vent. It is strictly chemolithoautotrophic, microaerophilic, motile, 2-4 micrometres in size, rod-shaped, Gram-negative and non-sporulating. Its type strain is EX-H2T.
Thermococcus barophilus is a barophilic and hyperthermophilic archaeon isolated from a deep-sea hydrothermal vent. It is anaerobic and sulfur-metabolising, with type strain MPT.
Balnearium lithotrophicum is a species of bacterium described in 2003 and classified as belonging to the Aquificota.
Desulfurobacterium atlanticum is a thermophilic, anaerobic and chemolithoautotrophic bacterium from the family Aquificaceae. In 2006 it was isolated from marine hydrothermal systems and proposed to become a new bacterial species.
Aciduliprofundum boonei is an obligate thermoacidophilic archaea belonging to the phylum Euryarchaeota. Isolated from acidic hydrothermal vent environments, A. boonei is the first cultured representative of a biogeochemically significant clade of thermoacidophilic archaea known as the “Deep-Sea Hydrothermal Vent Euryarchaeota 2 (DHVE2)”.
Caloranaerobacter azorensis is a Gram-negative, thermophilic, anaerobic, chemoorganotrophic and motile bacterium from the genus of Caloranaerobacter which has been isolated from a deep-sea hydrothermal vent from the Lucky Strike hydrothermal vent site from the Mid-Atlantic Ridge.
The hydrothermal vent microbial community includes all unicellular organisms that live and reproduce in a chemically distinct area around hydrothermal vents. These include organisms in the microbial mat, free floating cells, or bacteria in an endosymbiotic relationship with animals. Chemolithoautotrophic bacteria derive nutrients and energy from the geological activity at Hydrothermal vents to fix carbon into organic forms. Viruses are also a part of the hydrothermal vent microbial community and their influence on the microbial ecology in these ecosystems is a burgeoning field of research.
Thermodesulfobacterium hveragerdense is a bacterial species belonging to genus Thermodesulfobacterium, which are thermophilic sulfate-reducing bacteria. This species is found in aquatic areas of high temperature, and lives in freshwater like most, but not all Thermodesulfobacterium species It was first isolated from hotsprings in Iceland.
References
- 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 Götz, D; Banta, A; Beveridge, T J; Rushdi, A I; Simoneit, B R T; Reysenbach, A L (2002-01-01). "Persephonella marina gen. nov., sp. nov. and Persephonella guaymasensis sp. nov., two novel, thermophilic, hydrogen-oxidizing microaerophiles from deep-sea hydrothermal vents". International Journal of Systematic and Evolutionary Microbiology. 52 (4): 1349–1359. doi: 10.1099/00207713-52-4-1349 . PMID 12148650.
- ↑ Reysenbach, Anna-Louise; Hamamura, N.; Podar, M.; Griffiths, E.; Ferreira, S.; Hochstein, R.; Heidelberg, J.; Johnson, J.; Mead, D. (2009-03-15). "Complete and Draft Genome Sequences of Six Members of the Aquificales". Journal of Bacteriology. 191 (6): 1992–1993. doi:10.1128/JB.01645-08. ISSN 0021-9193. PMC 2648382 . PMID 19136599.
- ↑ Costa, Joana; Empadinhas, Nuno; Costa, Milton S. da (2007-03-01). "Glucosylglycerate Biosynthesis in the Deepest Lineage of the Bacteria: Characterization of the Thermophilic Proteins GpgS and GpgP from Persephonella marina". Journal of Bacteriology. 189 (5): 1648–1654. doi:10.1128/JB.00841-06. ISSN 0021-9193. PMC 1855766 . PMID 17189358.
- 1 2 3 4 5 6 7 8 Lamosa, Pedro; Rodrigues, Marta V.; Gonçalves, Luís G.; Carr, Jean; Ventura, Rita; Maycock, Christopher; Raven, Neil D.; Santos, Helena (2013-01-01). "Organic solutes in the deepest phylogenetic branches of the Bacteria: identification of α(1–6)glucosyl-α(1–2)glucosylglycerate in Persephonella marina". Extremophiles. 17 (1): 137–146. doi:10.1007/s00792-012-0500-x. ISSN 1431-0651. PMID 23179593. S2CID 17761508.