What is Euryarchaeota in biology?
Euryarchaeota. Euryarchaeota (Greek for "broad old quality") is a phylum of archaea. The Euryarchaeota are highly diverse and include methanogens, which produce methane and are often found in intestines, halobacteria, which survive extreme concentrations of salt, and some extremely thermophilic aerobes and anaerobes.
Are Euryarchaeota obligate or facultative aerobes?
The euryarchaeota Halobacteria, Thermoplasma, and many species of the crenarchaeota comprising genera as Sulfolobus, Acidianus, Metallosphera, or Pyrobaculum are obligate or facultative aerobes. Their respiratory systems essentially resemble modular components of respiratory chains as found in oxygen-respiring bacteria.
What are the different divisions of the Euryarchaeota?
…subdivisions, the Crenarchaeota and the Euryarchaeota, and one minor ancient lineage, the Korarchaeota. Other subdivisions have been proposed, including Nanoarchaeota and Thaumarchaeota.
Is Euryarchaeota Gram positive or negative?
Euryarchaeota may appear either gram-positive or gram-negative depending on whether pseudomurein is present in the cell wall. Euryarchaeota also demonstrate diverse lifestyles, including methanogens, halophiles, sulfate-reducers, and extreme thermophiles in each.
What is Euryarchaeota common name?
Euryarchaeota (Greek for "broad old quality") is a phylum of archaea. It is one of two phyla of archaea, the other being crenarchaeota.
What species is Euryarchaeota?
The phylum Euryarchaeota includes several distinct classes. Species in the classes Methanobacteria, Methanococci, and Methanomicrobia represent Archaea that can be generally described as methanogens.
What domain is Euryarchaeota?
ArchaeansEuryarchaeota / DomainArchaea constitute a domain of single-celled organisms. These microorganisms lack cell nuclei and are therefore prokaryotes. Archaea were initially classified as bacteria, receiving the name archaebacteria, but this term has fallen out of use. Wikipedia
What is Euryarchaeota used for?
classification and characteristics of archaea In the subdivision Euryarchaeota, uncultivated organisms in deep-sea marine sediments are responsible for the removal of methane, a potent greenhouse gas, via anaerobic oxidation of methane stored in these sediments.
What is an example of Euryarchaeota?
Haloarcha...Methanob...Methanos...Halobacter...Thermoco...Thermopla...Euryarchaeota/Lower classifications
What is the difference between Crenarchaeota and Euryarchaeota?
Euryarchaeota appeared as a physiologically diverse group, which included extreme halophiles, thermophiles, and methanogens. Crenarchaeota exclusively included sulfur-dependent hyperthermophiles [2].
What are the characteristics of Euryarchaeota?
Euryarchaeota are highly diverse and include methanogens, which produce methane and are often found in intestines, halobacteria, which survive extreme concentrations of salt, and some extremely thermophilic aerobes and anaerobes, which generally live at temperatures between 41 and 122 °C.
Are Euryarchaeota thermophiles?
Many Euryarchaeota are extreme thermophiles. Some Euryarchaeota are acidophilic or thermoacidophilic.
How does Euryarchaeota reproduce?
They occur where sea water is trapped and allowed to evaporate. As the water level decreases so the salt concentration increases. All known extremely Halophilic Archaea stain gram negative, do not form resting stages or spores and reproduce by binary fission.
Are Methanobacteria bacteria?
4.6 Methanogenic bacteria Methanogens are archaea bacteria that produce methane as a metabolic by-product. Examples of methane-producing genera are Methanobacterium, Methanosarcina, Methanococcus, and Methanospirillum.
What are the different types of archaea?
Euryarcha...Bathyarch...Thermopro...Nitrososph...Natronoru...Methanos...Archaeans/Lower classifications
Where is Bathyarchaeota found?
The archaeal phylum Bathyarchaeota (formerly known as Miscellaneous Crenarchaeotal Group (MCG)) is one of the most abundant and ubiquitously distributed microorganisms living in diverse habitats such as marine/freshwater sediment, soil, bioreactor, animal-associated habitats, and the deep subsurface biosphere [1], [2], ...
Are Euryarchaeota thermophiles?
Many Euryarchaeota are extreme thermophiles. Some Euryarchaeota are acidophilic or thermoacidophilic.
What are the characteristics of Euryarchaeota?
Euryarchaeota are highly diverse and include methanogens, which produce methane and are often found in intestines, halobacteria, which survive extreme concentrations of salt, and some extremely thermophilic aerobes and anaerobes, which generally live at temperatures between 41 and 122 °C.
How does Euryarchaeota reproduce?
They occur where sea water is trapped and allowed to evaporate. As the water level decreases so the salt concentration increases. All known extremely Halophilic Archaea stain gram negative, do not form resting stages or spores and reproduce by binary fission.
Is halobacterium Salinarum a bacteria?
Halobacterium salinarum, formerly known as Halobacterium cutirubrum or Halobacterium halobium, is an extremely halophilic marine obligate aerobic archaeon. Despite its name, this is not a bacterium, but a member of the domain Archaea. It is found in salted fish, hides, hypersaline lakes, and salterns.
Where are euryarchaea found?
Microorganisms belonging to the phylum Euryarchaeota inhabit diverse environments: halophilic euryarchaea dominate in hypersaline environments such as solar salterns and salt lakes, methanogenic euryarchaea are found in intestines, anoxic sediments, and sludge digesters, while thermophilic euryarchaea thrive in thermal environments, e.g., hot springs and deep-sea hydrothermal vents. Euryarchaea are also abundant and active in oceanic surface waters.
What are the respiratory systems of euryarchaeota?
Their respiratory systems essentially resemble modular components of respiratory chains as found in oxygen-respiring bacteria. A significant difference is the lack of a proton translocating NADH:quinol oxidoreductase. Instead, type-II NADH dehydrogenases were found, whereas complex-II analogous succinate dehydrogenases are present in all aerobic archaea. Two groups of enzymes can be distinguished: one group resembles the properties of SDHs from bacteria and mitochondria, and the other represents a novel class with unusual iron–sulfur clusters, as well as additional ones in a subunit with homology to methanobacterial heterodisulfide reductase, suggesting a novel electron pathway to the quinone pool. In Halobacteria, menaquinone and ubiquinone function as membrane-integral electron acceptors; in Thermoplasma and thermoacidophilic crenarchaeota like Sulfolobales, these are replaced by caldariella quinone and a variety of similar sulfur-containing thiopheno-benzoquinones. Several archaea such as A. ambivalens contain only fragmentary respiratory chains established from NADH- and succinate-quinone reductases and a heme/Cu-type quinol oxidase as terminal electron acceptor; the latter serves as the only energy-conserving proton pump. Rieske Fe–S proteins are present in Halobacteria, Sulfolobales, and Pyrobaculum for example, but cytochrome c and regular quinol:cytochrome c reductases are absent in many species. Instead, analogous functions are replaced by alternate membrane protein assemblies, for example, the SoxLN complex of S. acidocaldarius, using different electron acceptors as, for example, a mono-heme b-type cytochrome and/or blue copper proteins like sulfocyanine from various Sulfolobus species, or halocyanines from Natronomonas or Halobacterium salinarum. The proton pumping terminal heme/Cu-type oxidases are organized as supercomplexes in some thermoacidophilic crenarchaeota that combine features of quinol- and cytochrome c oxidases. The best-investigated examples are the SoxM complex and the SoxABCD complex from Sulfolobus.
What are the methanogenic archaea?
Methanogenic archaea constitute a phylogenetically diverse group of strictly anaerobic Euryarchaeota with an energy metabolism that is restricted to the production of methane from CO2 + H 2, methanol, methylamines, formate, and/or acetate ( Thauer, 1988). Five orders of methanogens have been identified: Methanosarcinales, Merthanococcales, Methanomicrobiales, Methanopyrales, and Methanobacteriales. A recent review by Thauer and colleagues compared the physiological and biochemical properties of methanogenic archaea with and without cytochromes (Thauer et al., 2008 ). Methanogenic archaea with cytochromes all belong to the order of Methanosarcinales including the Methanosarcina, Methanolobus, and Methanosaeta genera. All members of the Methanosarcinales order also have a broad substrate spectrum and contain methanophenazine (a functional analogue of menaquinone) ( Abken et al., 1998 ). Methanogens with cytochromes have a much higher growth yield on CO 2 + H 2 and a higher threshold concentration for H 2 than methanogens without cytochromes. Methanogenic archaea with cytochromes contain no hyperthermophilic species and have doubling times generally higher than 10 h ( Thauer et al., 2008 ).
What kingdom is Haloarchaea?
All salt-loving halophilic Archaea (also called haloarchaea) belong to the kingdom Euryarchaeota and have been classified into a single order (Halobacteriales) and family (Halobacteriaceae); however, a diverse and increasing number of genera (28 at present) have been described (Table 1). Haloarchaea have been isolated from numerous environments of varying salinity and generally dominate over Bacteria and a few Eucarya at the highest salinity extremes. Haloarchaea predominate in environments such as artificial crystallizer ponds, shallow ponds for isolating salts from the sea, as well as natural solar salterns, where isolates of Halobacterium, Halorubrum, Haloarcula, Halogeometricum, and Haloquadratum (including a square-shaped species) are typically detected. The microbial composition of the Dead Sea, which contains an unusually high concentration of magnesium, and ancient salt deposits, some as old as 200 million years (from the Permian period), have yielded haloarchaeal isolates, such as Haloarcula, Halobacterium, Halococcus, Haloferax, and Halorubrum. The true age of isolates from ancient salt deposits is quite controversial, since some metabolic activity occurring in the entrapped state cannot be strictly ruled out. Another typical environmental niche for haloarchaea are other neutral and alkaline hypersaline lakes, for example, the north arm of Great Salt Lake in the western United States (separated from the south arm by a railroad causeway), Lake Assal in Djibouti, and Lake Magadi in the Rift Valley of Africa, where species of Haloarcula, Natronococcus, and Natronomonas have been isolated. Species of Halobiforma, Halomicrobium, Halogeometricum, and Haloterrigena have been isolated from less salty environments such as coastal oceans, marshes, and soils. Traditionally, halophilic Archaea, such as Halobacterium, were isolated from salted protein sources such as fish sauces and animal hides.
What are the two morphotypes of Archaea?
The morphotypes of archaeal viruses reflect the division of the domain Archaea into two kingdoms, the Euryarchaeota and the Crenarchaeota. All but two viruses of euryarchaeotes are typical head-and-tail phages, including virions with contractile and noncontractile tails, thus belonging to the families Myoviridae and Siphovoridae. All have double-stranded DNA genomes. Circular permutation and terminal redundancy of the genomes of some phages indicate a headful mechanism of packaging from concatemeric precursors.
How many euryarchaeal viruses are there?
Today, more than 110 euryarchaeal virus isolates or virus-like particles (VLPs) are described.
What phylum are halophilic archaea in?
Until 2012, all extremely halophilic archaea were included within the phylum Euryarchaeota. However, that year a new group of unusually small extremely halophilic Archaea was discovered in Australian solar salterns. This group turned out to be very widespread and rather abundant in hypersaline systems worldwide. It was later named as Nanohalorcheaota and included within the archaeal superphylum DPANN, formed by phyla belonging to the so-called “microbial dark matter”, since no culture representatives are available so far. Soon after, metagenomic analyses allowed the tentative assignment of new haloviruses to this newly discovered host.
Where are euryarchaea found?
Microorganisms belonging to the phylum Euryarchaeota inhabit diverse environments: halophilic euryarchaea dominate in hypersaline environments such as solar salterns and salt lakes, methanogenic euryarchaea are found in intestines, anoxic sediments, and sludge digesters, while thermophilic euryarchaea thrive in thermal environments, e.g., hot springs and deep-sea hydrothermal vents. Euryarchaea are also abundant and active in oceanic surface waters.
What are the respiratory complexes of the euryarchaeota?
Respiratory Complexes#N#The euryarchaeota Halobacteria, Thermoplasma, and many species of the crenarchaeota comprising genera as Sulfolobus, Acidianus, Metallosphera, or Pyrobaculum are obligate or facultative aerobes. Their respiratory systems essentially resemble modular components of respiratory chains as found in oxygen-respiring bacteria. A significant difference is the lack of a proton translocating NADH:quinol oxidoreductase. Instead, type-II NADH dehydrogenases were found, whereas complex-II analogous succinate dehydrogenases are present in all aerobic archaea. Two groups of enzymes can be distinguished: one group resembles the properties of SDHs from bacteria and mitochondria, and the other represents a novel class with unusual iron–sulfur clusters, as well as additional ones in a subunit with homology to methanobacterial heterodisulfide reductase, suggesting a novel electron pathway to the quinone pool. In Halobacteria, menaquinone and ubiquinone function as membrane-integral electron acceptors; in Thermoplasma and thermoacidophilic crenarchaeota like Sulfolobales, these are replaced by caldariella quinone and a variety of similar sulfur-containing thiopheno-benzoquinones. Several archaea like A. ambivalens contain only fragmentary respiratory chains established from NADH- and succinate-quinone reductases and a heme/Cu-type quinol oxidase as terminal electron acceptor; the latter serves as the only energy-conserving proton pump. Rieske Fe–S proteins are present in Halobacteria, Sulfolobales, and Pyrobaculum for example, but cytochrome c and regular quinol:cytochrome c reductases are absent in many species. Instead, analogous functions are replaced by alternate membrane protein assemblies, e.g., the SoxLN complex of S. acidocaldarius, using different electron acceptors as, for example, a mono-heme b-type cytochrome and/or blue copper proteins like sulfocyanine from various Sulfolobus species, or halocyanines from Natronomonas or Halobacterium salinarum. The proton pumping terminal heme/Cu-type oxidases are organized as supercomplexes in some thermoacidophilic creanarchaeota that combine features of quinol- and cytochrome c oxidases. The best-investigated examples are the SoxM complex and the SoxABCD complex from Sulfolobus.
How many species are in the halobacteria class?
The class Halobacteria, affiliated with the archaeal phylum Euryarchaeota, currently (May 2018) encompasses 3 orders and 6 families with a total of 59 genera and 246 species ( Table 1 ). The class was circumscribed on the basis of small subunit rRNA gene sequence similarity, the high salt requirement of its members, and their physiological and chemotaxonomic features.
What is the T. kodakaraensis genome?
T. kodakaraensis KOD1 is a sulfur-reducing hyperthermophilic Euryarchaeote that cohabits environments with Pyrococcus. Annotation of the 2.09 Mbp T. kodakaraensis genome revealed 2306 putative genes, half of which could be annotated. The presence of transposable genetic elements similar to Pyrococcus species suggested transfer of genes between the two related genera. However, a substantial number of genes (about 30%) were absent from Pyrococcus and unique to T. kodakaraensis. A facile gene knockout system has been developed for postgenomic analysis of this hyperthermophile and it has become a popular model for postgenomic studies among thermophiles.
Which order of marine generalists are both archaea and a heterotroph?
There are two Orders of marine generalist that are both archaea: the Archaeoglobales in the Euryarchaeota and the Desulfurococcales in the Crenarchaeota ( Table 1 ). They are obligate heterotrophs or facultative autotrophs that use a wide range of electron donors and acceptors. The Archaeoglobales reduce sulfate, thiosulfate, iron, and nitrate; although elemental sulfur inhibits their growth. Archaeoglobus are facultative autotrophs or heterotrophs that reduce sulfate and thiosulfate to hydrogen sulphide. In contrast, neither Ferroglobus nor Geoglobus can reduce sulfate. Ferroglobus species can oxidize Fe (II), hydrogen, sulphide, acetate, and aromatic compounds and reduce nitrate, thiosulfate, Fe 3+ -citrate, and ferrihydrite. Geoglobus species grow autotrophically by hydrogen oxidation and are obligately dependent on either Fe 3+ -citrate or ferrihydrite as terminal electron acceptors.
Is Euryarchaeota hyperthermophilic?
No virus has ever been reported to infect the hyperthermophilic Euryarchaeota. However, two major groups of VLPs, rod-shaped particles and spindle-shaped particles, have been observed in enrichment cultures of samples obtained from deep-sea hydrothermal vents. In 2003, such spindle-shaped VLPs were discovered in supernatant of a ‘Pyrococcus abysii ’ culture and were designated ‘ P. abysii ’ virus 1 (PAV1). PAV1 is continuously released, but does not cause lysis of host cells and cannot be induced to infectivity using ultraviolet or γ irradiation, mitomycin C, or heat or pressure shock. No viral genomes integrated into the host chromosome have been detected.
Where are euryarchaea found?from sciencedirect.com
Microorganisms belonging to the phylum Euryarchaeota inhabit diverse environments: halophilic euryarchaea dominate in hypersaline environments such as solar salterns and salt lakes, methanogenic euryarchaea are found in intestines, anoxic sediments, and sludge digesters, while thermophilic euryarchaea thrive in thermal environments, e.g., hot springs and deep-sea hydrothermal vents. Euryarchaea are also abundant and active in oceanic surface waters.
What are the respiratory complexes of the euryarchaeota?from sciencedirect.com
Respiratory Complexes#N#The euryarchaeota Halobacteria, Thermoplasma, and many species of the crenarchaeota comprising genera as Sulfolobus, Acidianus, Metallosphera, or Pyrobaculum are obligate or facultative aerobes. Their respiratory systems essentially resemble modular components of respiratory chains as found in oxygen-respiring bacteria. A significant difference is the lack of a proton translocating NADH:quinol oxidoreductase. Instead, type-II NADH dehydrogenases were found, whereas complex-II analogous succinate dehydrogenases are present in all aerobic archaea. Two groups of enzymes can be distinguished: one group resembles the properties of SDHs from bacteria and mitochondria, and the other represents a novel class with unusual iron–sulfur clusters, as well as additional ones in a subunit with homology to methanobacterial heterodisulfide reductase, suggesting a novel electron pathway to the quinone pool. In Halobacteria, menaquinone and ubiquinone function as membrane-integral electron acceptors; in Thermoplasma and thermoacidophilic crenarchaeota like Sulfolobales, these are replaced by caldariella quinone and a variety of similar sulfur-containing thiopheno-benzoquinones. Several archaea like A. ambivalens contain only fragmentary respiratory chains established from NADH- and succinate-quinone reductases and a heme/Cu-type quinol oxidase as terminal electron acceptor; the latter serves as the only energy-conserving proton pump. Rieske Fe–S proteins are present in Halobacteria, Sulfolobales, and Pyrobaculum for example, but cytochrome c and regular quinol:cytochrome c reductases are absent in many species. Instead, analogous functions are replaced by alternate membrane protein assemblies, e.g., the SoxLN complex of S. acidocaldarius, using different electron acceptors as, for example, a mono-heme b-type cytochrome and/or blue copper proteins like sulfocyanine from various Sulfolobus species, or halocyanines from Natronomonas or Halobacterium salinarum. The proton pumping terminal heme/Cu-type oxidases are organized as supercomplexes in some thermoacidophilic creanarchaeota that combine features of quinol- and cytochrome c oxidases. The best-investigated examples are the SoxM complex and the SoxABCD complex from Sulfolobus.
What are the methanogenic archaea?from sciencedirect.com
Methanogenic archaea constitute a phylogenetically diverse group of strictly anaerobic Euryarchaeota with an energy metabolism that is restricted to the production of methane from CO2 + H 2, methanol, methylamines, formate, and/or acetate ( Thauer, 1988). Five orders of methanogens have been identified: Methanosarcinales, Merthanococcales, Methanomicrobiales, Methanopyrales, and Methanobacteriales. A recent review by Thauer and colleagues compared the physiological and biochemical properties of methanogenic archaea with and without cytochromes (Thauer et al., 2008 ). Methanogenic archaea with cytochromes all belong to the order of Methanosarcinales including the Methanosarcina, Methanolobus, and Methanosaeta genera. All members of the Methanosarcinales order also have a broad substrate spectrum and contain methanophenazine (a functional analogue of menaquinone) ( Abken et al., 1998 ). Methanogens with cytochromes have a much higher growth yield on CO 2 + H 2 and a higher threshold concentration for H 2 than methanogens without cytochromes. Methanogenic archaea with cytochromes contain no hyperthermophilic species and have doubling times generally higher than 10 h ( Thauer et al., 2008 ).
What kingdom is Haloarchaea?from sciencedirect.com
All salt-loving halophilic Archaea (also called haloarchaea) belong to the kingdom Euryarchaeota and have been classified into a single order (Halobacteriales) and family (Halobacteriaceae); however, a diverse and increasing number of genera (28 at present) have been described (Table 1). Haloarchaea have been isolated from numerous environments of varying salinity and generally dominate over Bacteria and a few Eucarya at the highest salinity extremes. Haloarchaea predominate in environments such as artificial crystallizer ponds, shallow ponds for isolating salts from the sea, as well as natural solar salterns, where isolates of Halobacterium, Halorubrum, Haloarcula, Halogeometricum, and Haloquadratum (including a square-shaped species) are typically detected. The microbial composition of the Dead Sea, which contains an unusually high concentration of magnesium, and ancient salt deposits, some as old as 200 million years (from the Permian period), have yielded haloarchaeal isolates, such as Haloarcula, Halobacterium, Halococcus, Haloferax, and Halorubrum. The true age of isolates from ancient salt deposits is quite controversial, since some metabolic activity occurring in the entrapped state cannot be strictly ruled out. Another typical environmental niche for haloarchaea are other neutral and alkaline hypersaline lakes, for example, the north arm of Great Salt Lake in the western United States (separated from the south arm by a railroad causeway), Lake Assal in Djibouti, and Lake Magadi in the Rift Valley of Africa, where species of Haloarcula, Natronococcus, and Natronomonas have been isolated. Species of Halobiforma, Halomicrobium, Halogeometricum, and Haloterrigena have been isolated from less salty environments such as coastal oceans, marshes, and soils. Traditionally, halophilic Archaea, such as Halobacterium, were isolated from salted protein sources such as fish sauces and animal hides.
How do haloarchaea resist denaturation?from sciencedirect.com
Haloarchaea have been shown to resist the denaturing effects of high salt concentrations through a process of selective uptake of salts known as ‘salting in’ , which is used by few nonarchaeal organisms. The accumulation of salts internally, mainly KCl, reduces osmotic stress to the cell membrane but creates an intracellular milieu that is harsh and challenging for biological macromolecules. The internal salt concentration of most halophilic species, like Halobacterium, has been measured to be as high as the natural environment, up to 5 M salts, which would result in desolvation, aggregation, denaturation, and precipitation (via salting out) of most nonhaloarchaeal proteins. Some DNA sequences, for example, alternating GC sequences, morph into a left-handed form, called Z-DNA. Haloarchaeal cells maintain high internal KCl concentration and relatively low NaCl concentration, via both membrane potential and ATP-driven potassium uptake systems and sodium–proton antiporters ( Figure 5 ). The sodium-motive force is important for metabolic activities, like the uptake of amino acids, which generally are present in high concentrations during periods of increased salinity due to evaporation and resulting decline and decomposition of less halophilic species. Genomic analysis has also shown that the proteins of haloarchaea are highly acidic, and structural studies have revealed that surface negative charges facilitate the formation of a hydration shell, increasing their solubility and decreasing aggregation and precipitation. The high solar illumination of many hypersaline environments has also resulted in development of tolerance to radiation for haloarchaea via active DNA repair mechanisms, including both light repair (photolyase) and dark repair (nucleotide excision repair) systems. In fact, the most radiation-resistant strain as well as the most space condition-tolerant vegetative cells to have been found thus far are both haloarchaea.
What are the two morphotypes of Archaea?from sciencedirect.com
The morphotypes of archaeal viruses reflect the division of the domain Archaea into two kingdoms, the Euryarchaeota and the Crenarchaeota. All but two viruses of euryarchaeotes are typical head-and-tail phages, including virions with contractile and noncontractile tails, thus belonging to the families Myoviridae and Siphovoridae. All have double-stranded DNA genomes. Circular permutation and terminal redundancy of the genomes of some phages indicate a headful mechanism of packaging from concatemeric precursors.
What are the carbon sources of haloarchaea?from sciencedirect.com
Other carbon sources utilized by haloarchaea include sugars, glycerol, and hydrocarbons. Since their natural environments often have low oxygen concentrations (oxygen solubility is reduced by high salinity), many haloarchaea are able to grow anaerobically. Terminal electron acceptors during anaerobic growth include dimethylsulfoxide, trimethylamine, fumarate, nitrogen oxide, and in some cases nitrate. Certain species of haloarchaea are able to grow anaerobically via the fermentation of arginine.
What is the temperature of Euryarchaeota?from en.wikipedia.org
Euryarchaeota are highly diverse and include methanogens, which produce methane and are often found in intestines, halobacteria, which survive extreme concentrations of salt, and some extremely thermophilic aerobes and anaerobes, which generally live at temperatures between 41 and 122 °C.
Is Euryarchaeota gram positive or negative?from en.wikipedia.org
The phylum contains organisms of a variety of shapes, including both rods and cocci. Euryarchaeota may appear either gram-positive or gram-negative depending on whether pseudomurein is present in the cell wall.
Is euryarchaeota dependent on mycorrhizal fungi?from en.wikipedia.org
In rhizospheres, the presence of euryarchaeota seems to be dependent on that of mycorrhizal fungi; a higher fungal population was correlated with higher euryarchaeotal frequency and diversity, while absence of mycorrihizal fungi was correlated with absence of euryarchaeota.
Where are euryarchaea found?from sciencedirect.com
Microorganisms belonging to the phylum Euryarchaeota inhabit diverse environments: halophilic euryarchaea dominate in hypersaline environments such as solar salterns and salt lakes, methanogenic euryarchaea are found in intestines, anoxic sediments, and sludge digesters, while thermophilic euryarchaea thrive in thermal environments, e.g., hot springs and deep-sea hydrothermal vents. Euryarchaea are also abundant and active in oceanic surface waters.
What are the respiratory complexes of the euryarchaeota?from sciencedirect.com
Respiratory Complexes#N#The euryarchaeota Halobacteria, Thermoplasma, and many species of the crenarchaeota comprising genera as Sulfolobus, Acidianus, Metallosphera, or Pyrobaculum are obligate or facultative aerobes. Their respiratory systems essentially resemble modular components of respiratory chains as found in oxygen-respiring bacteria. A significant difference is the lack of a proton translocating NADH:quinol oxidoreductase. Instead, type-II NADH dehydrogenases were found, whereas complex-II analogous succinate dehydrogenases are present in all aerobic archaea. Two groups of enzymes can be distinguished: one group resembles the properties of SDHs from bacteria and mitochondria, and the other represents a novel class with unusual iron–sulfur clusters, as well as additional ones in a subunit with homology to methanobacterial heterodisulfide reductase, suggesting a novel electron pathway to the quinone pool. In Halobacteria, menaquinone and ubiquinone function as membrane-integral electron acceptors; in Thermoplasma and thermoacidophilic crenarchaeota like Sulfolobales, these are replaced by caldariella quinone and a variety of similar sulfur-containing thiopheno-benzoquinones. Several archaea like A. ambivalens contain only fragmentary respiratory chains established from NADH- and succinate-quinone reductases and a heme/Cu-type quinol oxidase as terminal electron acceptor; the latter serves as the only energy-conserving proton pump. Rieske Fe–S proteins are present in Halobacteria, Sulfolobales, and Pyrobaculum for example, but cytochrome c and regular quinol:cytochrome c reductases are absent in many species. Instead, analogous functions are replaced by alternate membrane protein assemblies, e.g., the SoxLN complex of S. acidocaldarius, using different electron acceptors as, for example, a mono-heme b-type cytochrome and/or blue copper proteins like sulfocyanine from various Sulfolobus species, or halocyanines from Natronomonas or Halobacterium salinarum. The proton pumping terminal heme/Cu-type oxidases are organized as supercomplexes in some thermoacidophilic creanarchaeota that combine features of quinol- and cytochrome c oxidases. The best-investigated examples are the SoxM complex and the SoxABCD complex from Sulfolobus.
What are the methanogenic archaea?from sciencedirect.com
Methanogenic archaea constitute a phylogenetically diverse group of strictly anaerobic Euryarchaeota with an energy metabolism that is restricted to the production of methane from CO2 + H 2, methanol, methylamines, formate, and/or acetate ( Thauer, 1988). Five orders of methanogens have been identified: Methanosarcinales, Merthanococcales, Methanomicrobiales, Methanopyrales, and Methanobacteriales. A recent review by Thauer and colleagues compared the physiological and biochemical properties of methanogenic archaea with and without cytochromes (Thauer et al., 2008 ). Methanogenic archaea with cytochromes all belong to the order of Methanosarcinales including the Methanosarcina, Methanolobus, and Methanosaeta genera. All members of the Methanosarcinales order also have a broad substrate spectrum and contain methanophenazine (a functional analogue of menaquinone) ( Abken et al., 1998 ). Methanogens with cytochromes have a much higher growth yield on CO 2 + H 2 and a higher threshold concentration for H 2 than methanogens without cytochromes. Methanogenic archaea with cytochromes contain no hyperthermophilic species and have doubling times generally higher than 10 h ( Thauer et al., 2008 ).
What kingdom is Haloarchaea?from sciencedirect.com
All salt-loving halophilic Archaea (also called haloarchaea) belong to the kingdom Euryarchaeota and have been classified into a single order (Halobacteriales) and family (Halobacteriaceae); however, a diverse and increasing number of genera (28 at present) have been described (Table 1). Haloarchaea have been isolated from numerous environments of varying salinity and generally dominate over Bacteria and a few Eucarya at the highest salinity extremes. Haloarchaea predominate in environments such as artificial crystallizer ponds, shallow ponds for isolating salts from the sea, as well as natural solar salterns, where isolates of Halobacterium, Halorubrum, Haloarcula, Halogeometricum, and Haloquadratum (including a square-shaped species) are typically detected. The microbial composition of the Dead Sea, which contains an unusually high concentration of magnesium, and ancient salt deposits, some as old as 200 million years (from the Permian period), have yielded haloarchaeal isolates, such as Haloarcula, Halobacterium, Halococcus, Haloferax, and Halorubrum. The true age of isolates from ancient salt deposits is quite controversial, since some metabolic activity occurring in the entrapped state cannot be strictly ruled out. Another typical environmental niche for haloarchaea are other neutral and alkaline hypersaline lakes, for example, the north arm of Great Salt Lake in the western United States (separated from the south arm by a railroad causeway), Lake Assal in Djibouti, and Lake Magadi in the Rift Valley of Africa, where species of Haloarcula, Natronococcus, and Natronomonas have been isolated. Species of Halobiforma, Halomicrobium, Halogeometricum, and Haloterrigena have been isolated from less salty environments such as coastal oceans, marshes, and soils. Traditionally, halophilic Archaea, such as Halobacterium, were isolated from salted protein sources such as fish sauces and animal hides.
How do haloarchaea resist denaturation?from sciencedirect.com
Haloarchaea have been shown to resist the denaturing effects of high salt concentrations through a process of selective uptake of salts known as ‘salting in’ , which is used by few nonarchaeal organisms. The accumulation of salts internally, mainly KCl, reduces osmotic stress to the cell membrane but creates an intracellular milieu that is harsh and challenging for biological macromolecules. The internal salt concentration of most halophilic species, like Halobacterium, has been measured to be as high as the natural environment, up to 5 M salts, which would result in desolvation, aggregation, denaturation, and precipitation (via salting out) of most nonhaloarchaeal proteins. Some DNA sequences, for example, alternating GC sequences, morph into a left-handed form, called Z-DNA. Haloarchaeal cells maintain high internal KCl concentration and relatively low NaCl concentration, via both membrane potential and ATP-driven potassium uptake systems and sodium–proton antiporters ( Figure 5 ). The sodium-motive force is important for metabolic activities, like the uptake of amino acids, which generally are present in high concentrations during periods of increased salinity due to evaporation and resulting decline and decomposition of less halophilic species. Genomic analysis has also shown that the proteins of haloarchaea are highly acidic, and structural studies have revealed that surface negative charges facilitate the formation of a hydration shell, increasing their solubility and decreasing aggregation and precipitation. The high solar illumination of many hypersaline environments has also resulted in development of tolerance to radiation for haloarchaea via active DNA repair mechanisms, including both light repair (photolyase) and dark repair (nucleotide excision repair) systems. In fact, the most radiation-resistant strain as well as the most space condition-tolerant vegetative cells to have been found thus far are both haloarchaea.
What are the two morphotypes of Archaea?from sciencedirect.com
The morphotypes of archaeal viruses reflect the division of the domain Archaea into two kingdoms, the Euryarchaeota and the Crenarchaeota. All but two viruses of euryarchaeotes are typical head-and-tail phages, including virions with contractile and noncontractile tails, thus belonging to the families Myoviridae and Siphovoridae. All have double-stranded DNA genomes. Circular permutation and terminal redundancy of the genomes of some phages indicate a headful mechanism of packaging from concatemeric precursors.
What are the carbon sources of haloarchaea?from sciencedirect.com
Other carbon sources utilized by haloarchaea include sugars, glycerol, and hydrocarbons. Since their natural environments often have low oxygen concentrations (oxygen solubility is reduced by high salinity), many haloarchaea are able to grow anaerobically. Terminal electron acceptors during anaerobic growth include dimethylsulfoxide, trimethylamine, fumarate, nitrogen oxide, and in some cases nitrate. Certain species of haloarchaea are able to grow anaerobically via the fermentation of arginine.
Does Euryarchaeota have nucleus?
Thermoplasma. Thermoplasma, (genus Thermoplasma), any of a group of prokaryotic organisms (organisms whose cells lack a defined nucleus) in the domain Archaea that are noted for their ability to thrive in hot, acidic environments.
What is the difference between crenarchaeota and Euryarchaeota?
Euryarchaeota appeared as a physiologically diverse group, which included extreme halophiles, thermophiles, and methanogens. Crenarchaeota exclusively included sulfur-dependent hyperthermophiles [2].
Where would you likely find Euryarchaeota bacteria?
Methanogens are commonly found in the guts of animals, deep layers of marine sediment, hydrothermal vents, and wetlands. They are responsible for the methane in the belches of ruminants, as in, the flatulence in humans, and the marsh gas of wetlands.
Is archaebacteria eukaryotic or prokaryotic?
The archaebacteria are a group of prokaryotes which seem as distinct from the true bacteria (eubacteria) as they are from eukaryotes.
What is the cell structure of archaebacteria?
Basic Archaeal Structure : The three primary regions of an archaeal cell are the cytoplasm, cell membrane, and cell wall. Above, these three regions are labelled, with an enlargement at right of the cell membrane structure.
Why archaebacteria are called living fossils?
They are called so as they represent one of the earliest forms of life that experimented on the absorption of solar rays for the first time, thrived under anaerobic conditions and adapted techniques to oxidize chemicals found in the substratum in the presence of oxygen.
What is Fimbriae microbiology?
Fimbriae are long filamentous polymeric protein structures located at the surface of bacterial cells. They enable the bacteria to bind to specific receptor structures and thereby to colonise specific surfaces.
