| Metallosphaera hakonensis | |
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| Species: | M. hakonensis |
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| Metallosphaera hakonensis (Takayanagi et al., 1996) Kurosawa et al., 2003 | |
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Metallosphaera hakonensis is a gram-negative, thermoacidophilic archaea discovered in the hot springs of Hakone National Park, Kanagawa, Japan. [1]
Metallosphaera hakonensis was isolated in 1996 by Takayanagi et al. from a hot spring in the Hakone National Park in Kanagawa, Japan. [1] Originally classified as a member of the genus Sulfolobus , [1] Kurosawa et al. determined through genetic testing that the organism belongs to the Metallosphaera genus in 2003. [2] Takayanagi et al. determined a 92% similarity with Sulfolobus species; however, Kurosawa et al. determined a 98% similarity with Metallosphaera species. [1] [2] Using the more accurate high-performance liquid chromatography method, Kurosawa et al. also determined a new G+C content (43.29%) that is characteristic of Metallosphaera species. [2]
Takayanagi et al. collected a water sample from a hot spring in the Hakone National Park in Kanagawa, Japan, with a pH 1.5 and a temperature of 91.5 °C. [1] A 1:10 mL dilution of the sample and modified Allen's medium, a media known to sustain Sulfolobus species, was made and incubated at 70 °C for about one week. [1] This sample was then used to form a 1:9 mL dilution with Allen's media, and a portion streaked onto 1.0% Geltrite plates containing Allen's media during exponential growth. [1] After incubation at 70 °C, an isolated colony of M. hakonensis was used to inoculate fresh broth, incubated, and plated. [1] This procedure was performed an additional time to isolate the archaea. [1]
M. hakonensis can grow in temperatures between 50 °C and 80 °C and between pH values 1.0 and 4.0. [1] M. hakonensis's optimal growth conditions are 70 °C and pH 3.0. [1] Some Metallosphaera species, such as M. prunae, are mobile by means of flagellum; however, M. hakonensis does not have a flagellum. [2] M. hakonensis is gram-negative and has either spherical or irregular polyhedron-shaped cells (lobe-shaped cells), that are 0.9 to 1.1 m in diameter. [1]
M. hakonensis has genome that is about 2.3 Mbp long and has a G+C content of 43.29% determined through Ion Torrent Sequencing and assembled using the Newbler v. 2.8 software. [3] [4] M.hakonensis’s genome contains 3,357 protein coding genes and 57 RNA genes determined using the Joint Genome Institute's gene calling methods and IMG's annotation pipeline [3] Near neighbors include Metallosphaera prunae, M. sedula, and M. yellowstonensis. [2] M. hakonensis has a 98% similarity in the 16S rRNA sequence to the other members of the genus Metallosphaera. [2]
Genome sequencing of M. hakonensis has revealed the presence of genes coding for enzyme Urease, with genes present for subunits A and B. [3] Urease catalyzes the degradation of urea to ammonia and bicarbonate. [5] Sequences also revealed the presence of genes for haloacetate dehalogenase. [3] Haloacetate dehalogenase catalyzes the conversion of haloacetate to glycolate and the halide ion(e.g. fluoride). [3] M. hakonensis also contains the gene for maleylacetate reductase, a key component in biological degradation of halogenated aromatic organic compounds. [6] [3]
Organisms belonging to the genus Metallosphaera are found in extreme environments such as volcanic fields [7] and hot waste material in mines. [8]
M. hakonensis is an obligate aerobic chemolithoautotroph that utilizes sulfur oxidation as its main source of energy. [1] M. hakonensis is capable of utilizing yeast extract (excluding sugars), L-glutamic acid, L-tryptophan, maltose, and sulfur compounds such as elemental sulfur and hydrogen sulfide as energy sources, similar to other Metallosphaera species. [1] [2] M. hakonensis exhibits poor growth in media containing L-glutamic acid, L-tryptophan, and maltose. [1] One unique feature of M. hakonensis is its ability to utilize FeS clusters and the sulfur anion, tetrathionate (O6S42-). [2]
M. hakonensis is an extremophile, exhibiting characteristics of both thermophiles and acidophiles. [1] The advancement in the research of M. hakonensis is important because extremophiles are widely thought to be more closely related to the "universal ancestor" on the tree of life than most organisms. [9] Sequencing data of this organism contributes to the attempt to reconstruct a genome similar to the last universal common ancestor (LUCA). [9] Future research into extremophiles will allow for advancements in the field of evolutionary biology and further insight into the last universal common ancestor (LUCA) and its developmental environment. [9] Furthermore, astrobiology also places great importance on the study of extremophiles. [9] It is believed that life began on Earth when the environment was anoxic and had a thin atmosphere with extreme temperatures, similar to Mars. [9] Due to the vastness of the universe and millions of planetary systems, it is plausible to believe that life exists outside of Earth. With many planets displaying extreme surface environments, the study of extremophiles (including M. hakonensis) allows scientists to develop hypotheses about environmental conditions required for the development of life, as well as the role of this new life on the evolution of other planets. [10]
Based on sequencing data, M. hakonensis contains the gene for maleylacetate reductase, a key component in biological degradation of halogenated aromatic organic compounds. [3] [6] Based on recent studies, halogenated aromatic compounds have become a pollutant of food products. [11] Other benzene derivatives have been known to pollute many environments including the air; these compounds are known as BTEX pollutants. [12] The study of the gene for and enzyme maleylacetate reductase can play a role in control of future pollution by aromatic organic compounds. Sequencing data of M. hakonensis also revealed the presence of the gene for Urease, a common virulence factor found in gastro-pathogenic bacteria such as Helicobacter pylori , a common infection causing about 14,500 deaths per year. [13] [3] Urease catalyzes the degradation of urea to ammonia and bicarbonate, increasing the pH of the stomach, which allows for survival and manifestation of the pathogens. [14] Recent studies have revealed that Urease also plays a role in fungal virulence, found in organisms such as C. neoformans and Co. posadasii. [14] Urease causes a shift in immune response from a Type 1 (Th1 cells) immune response to a Type 2 (Th2 cells) immune response, reducing the ability of the host immune response to prevent infection. [14] The knockout of Urease has also proven to decrease virulence capabilities of the fungi. [14] With its wide role in both fungal and bacterial infections, Urease has become an emerging target for current pharmaceutical advancements. [15]
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.
Sulfolobus is a genus of microorganism in the family Sulfolobaceae. It belongs to the archaea domain.
A thermoacidophile is an extremophilic microorganism that is both thermophilic and acidophilic; i.e., it can grow under conditions of high temperature and low pH. The large majority of thermoacidophiles are archaea or bacteria, though occasional eukaryotic examples have been reported. Thermoacidophiles can be found in hot springs and solfataric environments, within deep sea vents, or in other environments of geothermal activity. They also occur in polluted environments, such as in acid mine drainage.
Pyrococcus furiosus is a heterotrophic, strictly anaerobic, extremophilic, model species of archaea. It is classified as a hyperthermophile because it thrives best under extremely high temperatures, and is notable for having an optimum growth temperature of 100 °C. P. furiosus belongs to the Pyrococcus genus, most commonly found in extreme environmental conditions of hydrothermal vents. It is one of the few prokaryotic organisms that has enzymes containing tungsten, an element rarely found in biological molecules.
Paracoccus denitrificans, is a coccoid bacterium known for its nitrate reducing properties, its ability to replicate under conditions of hypergravity and for being a relative of the eukaryotic mitochondrion.
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.
Dehalococcoides is a genus of bacteria within class Dehalococcoidia that obtain energy via the oxidation of hydrogen and subsequent reductive dehalogenation of halogenated organic compounds in a mode of anaerobic respiration called organohalide respiration. They are well known for their great potential to remediate halogenated ethenes and aromatics. They are the only bacteria known to transform highly chlorinated dioxins, PCBs. In addition, they are the only known bacteria to transform tetrachloroethene to ethene.
Thermoproteales are an order of archaeans in the class Thermoprotei. They are the only organisms known to lack the SSB proteins, instead possessing the protein ThermoDBP that has displaced them. The rRNA genes of these organisms contain multiple introns, which can be homing endonuclease encoding genes, and their presence can impact the binding of "universal" 16S rRNA primers often used in environmental sequencing surveys.
Sulfolobaceae are a family of the Sulfolobales belonging to the domain Archaea. The family consists of several genera adapted to survive environmental niches with extreme temperature and low pH conditions.
Microbial biodegradation is the use of bioremediation and biotransformation methods to harness the naturally occurring ability of microbial xenobiotic metabolism to degrade, transform or accumulate environmental pollutants, including hydrocarbons, polychlorinated biphenyls (PCBs), polyaromatic hydrocarbons (PAHs), heterocyclic compounds, pharmaceutical substances, radionuclides and metals.
Rhodopseudomonas palustris is a rod-shaped, Gram-negative purple nonsulfur bacterium, notable for its ability to switch between four different modes of metabolism.
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.
Sulfolobus metallicus is a coccoid shaped thermophilic archaeon. It is a strict chemolithoautotroph gaining energy by oxidation of sulphur and sulphidic ores into sulfuric acid. Its type strain is Kra 23. It has many uses that take advantage of its ability to grow on metal media under acidic and hot environments.
Sulfolobus tokodaii is a thermophilic archaeon. It is acidophilic and obligately aerobic. The type strain is 7. Its genome has been sequenced.
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.
Sulfolobus acidocaldarius is a thermoacidophilic archaeon that belongs to the phylum Thermoproteota. S. acidocaldarius was the first Sulfolobus species to be described, in 1972 by Thomas D. Brock and collaborators. This species was found to grow optimally between 75 and 80 °C, with pH optimum in the range of 2-3.
Metallosphaera sedula is a species of Metallosphaera that is originally isolated from a volcanic field in Italy. Metallosphaera sedula can be roughly translated into “metal mobilizing sphere” with the word “sedulus” meaning busy, describing its efficiency in mobilizing metals. M. sedula is a highly thermoacidophilic Archaean that is unusually tolerant of heavy metals.
"Candidatus Aciduliprofundum boonei" is an obligate thermoacidophilic candidate species of archaea belonging to the phylum "Euryarchaeota". Isolated from acidic hydrothermal vent environments, "Ca. 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)".
Xenophilus azovorans is a bacterium from the genus Xenophilus which has been isolated from soil in Switzerland.
Sulfurisphaera tokodaii is a thermophilic archaeon of the Thermoproteota phylum. This species lives can grow as a chemoheterotroph and a lithoautotroph
