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Sulfolobus solfataricus | |
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Species: | S. solfataricus |
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Sulfolobus solfataricus Zillig et al. 1980 | |
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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. [1]
It was first discovered and isolated from the Solfatara volcano (Pisciarelli-Campania, Italy) in 1980 by two German microbiologists Karl Setter and Wolfram Zillig. [2]
However, these organisms are not isolated to volcanoes but are found all over the world in places such as hot springs. The species grows best in temperatures around 80 °C, a pH level between 2 and 4, and with enough sulfur for S.solfataricus to metabolize in order to gain energy. These conditions qualify it as an extremophile and it is specifically known as a thermoacidophile because of its preference for high temperatures and low pH levels. It is also aerobic and heterotropic due to its metabolic system. [3] Being an autotroph, it receives energy by growing on sulfur or even a variety of organic compounds. [4] It usually has a spherical cell shape and it makes frequent lobes.
Currently, it is the most widely studied organism within the Thermoproteota branch. Solfataricus are examined for their methods of DNA replication, cell cycle, chromosomal integration, transcription, RNA processing, and translation. All of the data points to the organism having a large percent of archaeal-specific genes, which shows the differences between the three types of microbes: archaea, bacteria, and eukaryote.
Sulfolobus solfataricus is the most studied microorganism from a molecular, genetic, and biochemical point of view for its ability to thrive in extreme environments. It can grow easily in the laboratory; moreover, it can exchange genetic material through processes of transformation, transduction. and conjugation.
The major motivation for sequencing these microorganisms is the thermostability of proteins that normally denature at a high temperature. The complete sequence the genome of S. solfataricus was completed in 2001. [5] On a single chromosome, there are 2,992,245 base pairs which encode for 2,977 proteins and copious RNAs. One-third of S. solfataricus encoded proteins have no homologs in other genomes. For the remaining encoded proteins, 40% are specific to Archaea, 12% are shared with Bacteria, and 2.3% are shared with Eukaryote; [6] 33% of these proteins are encoded exclusively in Sulfolobus. A high number of open reading frame s (ORFs) are highly similar in Thermoplasma. [3]
Small nucleolar RNAs (snoRNAs), already present in eukaryotes, have also been identified in S. solfataricus and S. acidolcaldarius. They are already known for the role they play in post-transcriptional modifications and removal of introns from ribosomal RNA in Eukaryote. [7]
The genome of Sulfolobus is characterized by the presence of short tandem repeats, insertion and repetitive elements. It has a wide range of diversity with 200 different insertion sequence elements.
The stabilization of the double helix against denaturation, in the Archaea, is due to the presence of a particular thermophilic enzyme, reverse gyrase. It was discovered in hyper-thermophilic and thermophilic Archaea and Bacteria. There are two genes in Sulfolobus that each encode a reverse gyrase. [8] It is defined as an atypical DNA topoisomerase and the basic activity consists of the production of positive supercoils in a closed circular DNA. Positive supercoiling is important to prevent the formation of open complexes. Reverse gyrases are composed of two domains: the first one is the helicase and second one is the topoisomerase I. A possible role of reverse gyrase could be the use of positive supercoiling to assemble chromatin-like structures. [9] In 1997, scientists discovered another important feature of Sulfolobus: a type-II topoisomerase, called TopoVI, whose A subunit is homologous to the meiotic recombination factor, Spo11, which plays a predominant role in the initiation of meiotic recombination in all Eukaryotes. [10] [11]
S. solfataricus is composed of three topoisomerases of type I, TopA and two reverse gyrases, TopR1 and TopR2, and one topoisomerase of type II, TopoVI. [12]
In the phylum Thermoproteota, there are three proteins that bind to the minor groove of DNA-like histones, Alba, Cren7, and Sso7d, that are modified after the translation process. These histones are small and have been found in several strains of Sulfolobus but not in other genomes. Chromatin protein in Sulfolobus represent 1-5% of the total genome. They can have both structural and regulatory functions. These look like human HMG-box proteins, because of their influence on genomes, expression and stability, and epigenetic processes. [13] In species lacking histones, they can be acetylated and methylated like eukaryotic histones. [14] [15] [16] [17] Sulfolobus strains present different peculiar DNA binding proteins, such as the Sso7d protein family. They stabilize the double helix, preventing denaturation at high temperature and thus promoting annealing above the melting point. [18]
The major component of Archaea chromatin is represented by Sac10b family protein known as Alba (acetylation lowers binding affinity). [19] [20] These proteins are small, basic, and dimeric nucleic acid-binding proteins. Furthermore, it is conserved in most sequenced Archaea genomes. [21] [22] The acetylation state of Alba affects promoter access and transcription in vitro, whereas the methylation state of another Sulfolobus chromatin protein, Sso7D, is altered by culture temperature. [23] [24]
The work of Wolfram Zillig's group, representing early evidence of the eukaryotic characteristics of transcription in Archaea, has since made Sulfolobus an ideal model system for transcription studies. Recent studies in Sulfolobus, in addition to other Archaea species, mainly focus on the composition, function, and regulation of the transcription machinery and on fundamental conserved aspects of this process in both Eukaryotes and Archaea. [25]
Exposure of Saccharolobus solfataricus to the DNA damaging agents, ultraviolet (UV) irradiation, bleomycin, or mitomycin C, induces cellular aggregation. [26] Other physical stressors, such as changes in pH or temperature shift, do not induce aggregation, suggesting that the induction of aggregation is caused specifically by DNA damage. Ajon et al. [27] showed that UV-induced cellular aggregation mediates chromosomal marker exchange with high frequency. Recombination rates exceeded those of uninduced cultures by up to three orders of magnitude. Frols et al. [26] [28] and Ajon et al. [27] hypothesized that the UV-induced DNA transfer process and subsequent homologous recombinational repair represents an important mechanism to maintain chromosome integrity. This response may be a primitive form of sexual interaction, similar to the more well-studied bacterial transformation that is also associated with DNA transfer between cells, leading to homologous recombinational repair of DNA damage. [29]
Sulfolobus solfataricus is known to grow by chemoorganotrophy, in the presence of oxygen, on a variety of organic compounds such as sugars, alcohols, amino acids, and aromatic compounds like phenol. [30]
It uses a modified Entner-Doudroff pathway for glucose oxidation and the resulting pyruvate molecules can be totally mineralized in a TCA cycle. [30]
Molecular oxygen is the only known electron acceptor at the end of the electron transport chain. [31] Other than organic molecules, this Archaea species can also utilize hydrogen sulfide [6] and elementary sulfur as electron donors and fix CO2, possibly by means of the HP/HB cycle, [30] making it also capable of living by chemoautotrophy. Recent studies have also found the capability of growing, albeit slowly, by oxidizing molecular hydrogen. [1]
Ferredoxin is suspected to act as the major metabolic electron carrier in S. solfataricus. This contrasts with most species within the Bacteria and Eukaryote groups of organisms, which generally rely on nicotinamide adenine dinucleotide hydrogen (NADH) as the main electron carrier. S. solfataricus has strong eukaryotic features coupled with many uniquely archaeal-specific abilities. The results of the findings came from the varied methods of their DNA mechanisms, cell cycles, and transitional apparatus. Overall, the study was a prime example of the differences found in Thermoproteota and "Euryarchaeota". [6] [32]
S. solfataricus is an extreme thermophile Archaea, as the rest of the species of the genus Sulfolobus, has optimal growth conditions in strong volcanic activity areas, with high temperatures and very acidic pH. [33] These specific conditions are typical of volcanic areas such as geyser or thermal springs. In fact, the most studied countries where these microorganisms were found are U.S.A. (Yellowstone National Park), [34] New Zealand, [35] Island and Italy, notoriously famous for volcanic phenomena. A study conducted by a team of Indonesian scientists has also shown the presence of a Sulfolobus community in West Java, confirming that high temperatures, low pH, and the presence of sulfur are necessary conditions for the growth of these microbes. [36]
S. solfataricus is able to oxidize sulfur according to metabolic strategy. One of the products of these reactions is H+ and, consequentially, it results in a slowly acidification of the surrounding area. Soil acidification increases in places where there are emissions of pollutants from industrial activity, and this process reduces the number of heterotrophic bacteria involved in decomposition, which are fundamental to recycling organic matter and ultimately to fertilizing soil. [37]
Today, in many fields of application, there is interest in using S. sulfataricus as a source of thermal stability enzymes for research and diagnostics as well as in the food, textile, cleaning, and pulp and paper industries. Furthermore, this enzyme is overloaded due to its catalytic diversity, high pH, and temperature stability, increased to organic solvents and resistance to proteolysis. [38] [39]
At present, tetra ester lipids, membrane vesicles with antimicrobial properties, trehalose components, and new β-galactooligosaccharides are becoming increasingly important. [40]
The thermostable enzyme β-galactosidase was isolated from the extreme thermophile archaebacterial S. solfataricus, strain MT-4.
This enzyme is utilized in many industrial processes of lactose containing fluids by purifying and characterizing their physicochemical properties. [41]
The industry are interested in stable proteases as well as in many different Sulfolobus proteases that have been studied. [42]
An active aminopeptidase associated with the chaperonin of S. solfataricus MT4 was described. [43]
Sommaruga et al. (2014) [44] also improved the stability and reaction yield of a well-characterized carboxypeptidase from S. solfataricus MT4 by magnetic nanoparticles immobilizing the enzyme.
A new thermostable extracellular lipolytic enzyme serine arylesterase was originally discovered for their large action in the hydrolysis of organophosphates from the thermoacidophilic archaeon S. solfataricus P1. [45]
In reaction to temperature shock (50.4 °C) in E. coli cells, a tiny warm stun protein (S.so-HSP20) from S.solfataricus P2 has been effectively used to improve tolerance to temperature. [46]
In view of the fact that chaperonin Ssocpn (920 kDa), which includes adenosine triphosphate (ATP), K+, and Mg2 +, has not produced any additional proteins in S. solfataricus to supply collapsed and dynamic proteins from denatured materials, it was stored on an ultrafiltration cell, while the renatured substrates were moving through the film. [47]
Because of its tetraether lipid material, the membrane of extreme thermophilic Archaea is unique in its composition. Archaea lipids are a promising source of liposomes with exceptional stability of temperature, pH, and tightness against the leakage of solute. Such archaeosomes are possible instruments for the delivery of medicines, vaccines, and genes. [48]
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.
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.
DNA primase is an enzyme involved in the replication of DNA and is a type of RNA polymerase. Primase catalyzes the synthesis of a short RNA segment called a primer complementary to a ssDNA template. After this elongation, the RNA piece is removed by a 5' to 3' exonuclease and refilled with DNA.
A hyperthermophile is an organism that thrives in extremely hot environments—from 60 °C (140 °F) upwards. An optimal temperature for the existence of hyperthermophiles is often above 80 °C (176 °F). Hyperthermophiles are often within the domain Archaea, although some bacteria are also able to tolerate extreme temperatures. Some of these bacteria are able to live at temperatures greater than 100 °C, deep in the ocean where high pressures increase the boiling point of water. Many hyperthermophiles are also able to withstand other environmental extremes, such as high acidity or high radiation levels. Hyperthermophiles are a subset of extremophiles. Their existence may support the possibility of extraterrestrial life, showing that life can thrive in environmental extremes.
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.
Microbial genetics is a subject area within microbiology and genetic engineering. Microbial genetics studies microorganisms for different purposes. The microorganisms that are observed are bacteria and archaea. Some fungi and protozoa are also subjects used to study in this field. The studies of microorganisms involve studies of genotype and expression system. Genotypes are the inherited compositions of an organism. Genetic Engineering is a field of work and study within microbial genetics. The usage of recombinant DNA technology is a process of this work. The process involves creating recombinant DNA molecules through manipulating a DNA sequence. That DNA created is then in contact with a host organism. Cloning is also an example of genetic engineering.
Sulfolobales is an order of archaeans in the class Thermoprotei.
In taxonomy, Thermococcus is a genus of thermophilic Archaea in the family the Thermococcaceae.
Icerudivirus is a genus of viruses in the family Rudiviridae. These viruses are non-enveloped, stiff-rod-shaped viruses with linear dsDNA genomes, that infect hyperthermophilic archaea of the species Sulfolobus islandicus. There are three species in the genus.
Archaea is a domain of organisms. Traditionally, Archaea only included its prokaryotic members, but this sense 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.
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.
Methanocaldococcus jannaschii is a thermophilic methanogenic archaean in the class Methanococci. It was the first archaeon, and third organism, to have its complete genome sequenced. The sequencing identified many genes unique to the archaea. Many of the synthesis pathways for methanogenic cofactors were worked out biochemically in this organism, as were several other archaeal-specific metabolic pathways.
Thermococcus kodakarensis is a species of thermophilic archaea. The type strain T. kodakarensis KOD1 is one of the best-studied members of the genus.
The archaellum is a unique structure on the cell surface of many archaea that allows for swimming motility. The archaellum consists of a rigid helical filament that is attached to the cell membrane by a molecular motor. This molecular motor – composed of cytosolic, membrane, and pseudo-periplasmic proteins – is responsible for the assembly of the filament and, once assembled, for its rotation. The rotation of the filament propels archaeal cells in liquid medium, in a manner similar to the propeller of a boat. The bacterial analog of the archaellum is the flagellum, which is also responsible for their swimming motility and can also be compared to a rotating corkscrew. Although the movement of archaella and flagella is sometimes described as "whip-like", this is incorrect, as only cilia from Eukaryotes move in this manner. Indeed, even "flagellum" is a misnomer, as bacterial flagella also work as propeller-like structures.
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.
Betalipothrixvirus hveragerdiense (SIFV) is an archaeal virus, classified in the family Lipothrixviridae within the order Ligamenvirales. The virus infects hypethermophilic and acidophilic archaeon Sulfolobus islandicus.
Reverse gyrase is a type I topoisomerase that introduces positive supercoils into DNA, contrary to the typical negative supercoils introduced by the type II topoisomerase DNA gyrase. These positive supercoils can be introduced to DNA that is either negatively supercoiled or fully relaxed. Where DNA gyrase forms a tetramer and is capable of cleaving a double-stranded region of DNA, reverse gyrase can only cleave single stranded DNA. More specifically, reverse gyrase is a member of the type IA topoisomerase class; along with the ability to relax negatively or positively supercoiled DNA, type IA enzymes also tend to have RNA-topoisomerase activities. These RNA topoisomerases help keep longer RNA strands from becoming tangled in what are referred to as "pseudoknots." Due to their ability to interact with RNA, it is thought that this is one of the most ancient class of enzymes found to date.
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