Caldococcus | |
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Genus: | Caldococcus Aoshima et al. 1996 |
Type species | |
Caldococcus noboribetus Aoshima et al. 1996 | |
Species | |
Caldococcus is a genus of Archaea in the order Desulfurococcales. [1]
Caldococcus are a genus of Archaea found in the class Desulfurococcales. Members of the genus are strictly anaerobic, hyperthermophilic cocci that reduce sulfide and oxidize sulfur. They can be found in hyperthermal vents and hot springs such as those at Yellowstone National Park [2] [3]
Caldococcus noboribetus genes have been mutated to understand the characteristics of the isocitrate dehydrogenase ancestral protein. The mutant isocitrate dehydrogenase genes contain inferred ancestral sequences that have been expressed in E. coli cells. Expression of these genes resulted in proteins with ancestral amino acid sequences, which provided evidence for relationships with a hyperthermophilic universal ancestor. Thermostabilities of the purified enzymes had greater thermal stabilities than wild-type isocitrate dehydrogenase. This supports a hypothesis that last universal common ancestor was thermophilic or hyperthermophilic. This finding has implications for understanding the evolutionary history of other proteins as well for engineering protein thermostability for experimental or industrial purposes. [4]
A gene coding for isocitrate dehydrogenase (ICDH) was cloned from Caldococcus noboribetus and sequenced. An amino acid sequence of ICDH displayed similarities to bacterial ICDH genes found in both Vibrio and E. coli species. Sequences from the latter shared about 50% identity with the archaeal ICDH. The gene was expressed in E. coli by ligating it to a T7 promoter and the resulting molecular weight of the gene product was about 48,000. This estimate was consistent with an estimate from the deduced amino acid sequence. The gene product also displayed a NADP-dependency in order to function at 80 °C. The ICDH gene isolated from C. noboribetus demonstrated a higher thermostability than a host derived ICDH. [5] From this information, it is plausible that this species could provide information regarding an ancestral hyperthermophile. Such information would help build a complete phylogenetic tree of hyperthermophilic archeabacteria.
Caldococcus litoralis were published as a representative of a novel genus, based on a significant difference of 14% in the GC Content with Thermococcus celer, the only representative of Thermococcus known at the time the study was done in 1987. C. litoralis are irregularly shaped cocci, ranging from 0.7-2.1 μm in size. The species was isolated from hot volcanic vents at Hot Beach on the Kunashir Island, Japan It is a marine and extremely thermophilic archaebacterium capable of growth at 55-100 °C, with an optimum temperature of 88 °C. It is also capable of growth at pH values ranging from 5.9 -7.0 with an optimum at pH 6.4. Under optimal conditions, generation time is 44 minutes with 6 g of peptone per liter and elemental sulfur and an electron acceptor.
C. litoralis possesses monopolar filamentous bundles, and is strictly anaerobic. It utilizes peptides as a carbon and energy source; it grows in the presence of elemental sulfur, which it reduces to H2S.
C litoralis is resistant to vancomycin, chloramphenicol, benzylpenicillin, streptomycin and rifampicin. Its RNA polymerase does not react with antibodies against Desulfurococcus RNA polymerase. It has a GC-content of 41.0 ± 0. 2 mol%. Due to its GC-content and its morphological and physiological properties, the original isolate was assigned to a new genus, Caldococcus gen. nov., with the type strain C. litoralis sp. nov.; the type strain is Z-1301. [6]
It been suggested that C. litoralis be reclassified as Thermococcus litoralis Z-1301." T. litoralis is a more recently published species that was not known at the time the original study was performed. [7] This suggestion is supported by immunoblotting analyses indicating that the two are the same species. Additional support includes 96% homology between the two strains following DNA-DNA hybridization. [8]
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.
Isocitrate dehydrogenase (IDH) (EC 1.1.1.42) and (EC 1.1.1.41) is an enzyme that catalyzes the oxidative decarboxylation of isocitrate, producing alpha-ketoglutarate (α-ketoglutarate) and CO2. This is a two-step process, which involves oxidation of isocitrate (a secondary alcohol) to oxalosuccinate (a ketone), followed by the decarboxylation of the carboxyl group beta to the ketone, forming alpha-ketoglutarate. In humans, IDH exists in three isoforms: IDH3 catalyzes the third step of the citric acid cycle while converting NAD+ to NADH in the mitochondria. The isoforms IDH1 and IDH2 catalyze the same reaction outside the context of the citric acid cycle and use NADP+ as a cofactor instead of NAD+. They localize to the cytosol as well as the mitochondrion and peroxisome.
The Thermotogota are a phylum of the domain Bacteria. The phylum contains a single class, Thermotogae. The phylum Thermotogota is composed of Gram-negative staining, anaerobic, and mostly thermophilic and hyperthermophilic bacteria.
"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.
Sulfolobus is a genus of microorganism in the family Sulfolobaceae. It belongs to the archaea domain.
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.
Pyrococcus is a genus of Thermococcaceaen archaean.
In taxonomy, Thermococcus is a genus of thermophilic Archaea in the family the Thermococcaceae.
In taxonomy, Staphylothermus is a genus of the Desulfurococcaceae.[1]
Aeropyrum pernix is a species of extremophile archaea in the archaeal phylum Thermoproteota. It is an obligatorily thermophilic species. The first specimens were isolated from sediments in the sea off the coast of Japan.
Thermococcus litoralis is a species of Archaea that is found around deep-sea hydrothermal vents as well as shallow submarine thermal springs and oil wells. It is an anaerobic organotroph hyperthermophile that is between 0.5–3.0 μm (20–118 μin) in diameter. Like the other species in the order thermococcales, T. litoralis is an irregular hyperthermophile coccus that grows between 55–100 °C (131–212 °F). Unlike many other thermococci, T. litoralis is non-motile. Its cell wall consists only of a single S-layer that does not form hexagonal lattices. Additionally, while many thermococcales obligately use sulfur as an electron acceptor in metabolism, T. litoralis only needs sulfur to help stimulate growth, and can live without it. T. litoralis has recently been popularized by the scientific community for its ability to produce an alternative DNA polymerase to the commonly used Taq polymerase. The T. litoralis polymerase, dubbed the vent polymerase, has been shown to have a lower error rate than Taq but due to its proofreading 3’–5’ exonuclease abilities.
Thermococcus celer is a Gram-negative, spherical-shaped archaeon of the genus Thermococcus. The discovery of T. celer played an important role in rerooting the tree of life when T. celer was found to be more closely related to methanogenic Archaea than to other phenotypically similar thermophilic species. T. celer was the first archaeon discovered to house a circularized genome. Several type strains of T. celer have been identified: Vu13, ATCC 35543, and DSM 2476.
Thermococcus kodakarensis is a species of thermophilic archaea. The type strain T. kodakarensis KOD1 is one of the best-studied members of the genus.
Thermotoga maritima is a hyperthermophilic, anaerobic organism that is a member of the order Thermotogales. T. maritima is well known for its ability to produce hydrogen (clean energy) and it is the only fermentative bacterium that has been shown to produce Hydrogen more than the Thauer limit (>4 mol H2 /mol glucose). It employs [FeFe]-hydrogenases to produce hydrogen gas (H2) by fermenting many different types of carbohydrates.
Pyrococcus woesei is an ultra-thermophilic marine archaeon. It is sulfur-reducing and grows optimally between 100 and 103 °C. Its cells have a roughly spherical, elongated and constricted appearance, similar to Thermococcus celer. Frequently, they occur as diploforms. Cells grown on solid supports have dense tufts of flagella or pili attached to one pole.
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.
Thermotoga petrophila is a hyperthermophilic, anaerobic, non-spore-forming, rod-shaped, fermentative heterotroph, with type strain RKU-1T. T. petrophila was first discovered and isolated from an oil reservoir off of the coast of Japan and was deemed genetically distinct from its sister clades. Because these organism are found in deep, hot aquatic settings, they have become of great interest for biotechnology due to their enzymes functioning at high temperatures and pressures.
Thermococcus peptonophilus is a fast-growing hyperthermophilic archaeon. It is coccus-shaped, obligately anaerobic and about 0.7–2 μm in diameter. It is a strict anaerobe and grows exclusively on complex substrates, such as peptone, casein, tryptone, and yeast extract. It cannot use carbon dioxide as a source of carbon. Although it can grow somewhat in the absence of elemental sulfur, it prefers sulfur.
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.
Thermococcus hydrothermalis is a hyperthermophilic archaeon. It is strictly anaerobic and coccus-shaped, and its cells range from 0.8 to 2.0 μm in diameter, with type strain AL662T. It was isolated from a hydrothermal vent in the East Pacific Rise. This species is notable for its α-glucosidase, which functions optimally at a temperature of 110 °C.