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Nanoarchaeum Equitans
''Nanoarchaeum equitans'' is a species of marine archaea that was discovered in 2002 in a hydrothermal vent off the coast of Iceland on the Kolbeinsey Ridge by Karl Stetter. It has been proposed as the first species in a new phylum, and is the only species within the genus ''Nanoarchaeum''. Strains of this microbe were also found on the Sub-polar Mid Oceanic Ridge, and in the Obsidian Pool in Yellowstone National Park. Since it grows in temperatures approaching boiling, at about , it is considered to be a thermophile. It grows best in environments with a pH of 6, and a salinity concentration of 2%. ''Nanoarchaeum'' appears to be an obligate symbiont on the archaeon '' Ignicoccus''; it must be in contact with the host organism to survive. ''Nanoarchaeum equitans'' cannot synthesize lipids but obtains them from its host. Its cells are only 400 nm in diameter, making it the smallest known living organism, and the smallest known archaeon. ''N. equitans'' genome consists of a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ignicoccus
''Ignicoccus'' is a genus of hyperthermophillic Archaea living in marine hydrothermal vents. They were discovered in samples taken at the Kolbeinsey Ridge north of Iceland, as well as at the East Pacific Rise (at 9 degrees N, 104 degrees W) in 2000. Systematics According to the comparisons of 16S rRNA genes, ''Ignicoccus'' represents a new, deeply branching lineage within the family of the Desulfurococcaceae. Three species are known: ''I. islandicus'', ''I. pacificus'' and ''I. hospitalis'' strain KIN4I. Cell structure The archaea of the genus ''Ignicoccus'' have tiny coccoid cells with a diameter of about 2 μm, that exhibit a smooth surface, an outer membrane and no S-layer. They have a previously unknown cell envelope structure—a cytoplasmic membrane, a periplasmic space (with a variable width of 20 to 400 nm, containing membrane-bound vesicles), and an outer membrane (approximately 10 nm wide, resembling the outer membrane of gram-negative bacteria). The l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nucleotides
Nucleotides are Organic compound, organic molecules composed of a nitrogenous base, a pentose sugar and a phosphate. They serve as monomeric units of the nucleic acid polymers – deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), both of which are essential biomolecules within all Life, life-forms on Earth. Nucleotides are obtained in the diet and are also synthesized from common Nutrient, nutrients by the liver. Nucleotides are composed of three subunit molecules: a nucleobase, a pentose, five-carbon sugar (ribose or deoxyribose), and a phosphate group consisting of one to three phosphates. The four nucleobases in DNA are guanine, adenine, cytosine, and thymine; in RNA, uracil is used in place of thymine. Nucleotides also play a central role in metabolism at a fundamental, cellular level. They provide chemical energy—in the form of the nucleoside triphosphates, adenosine triphosphate (ATP), guanosine triphosphate (GTP), cytidine triphosphate (CTP), and uridine triph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nanoarchaeota
Nanoarchaeota (Greek, "dwarf or tiny ancient one") is a proposed phylum (''Candidatus'' Nanoarchaeota) in the domain Archaea that currently has only one representative, '' Nanoarchaeum equitans'', which was discovered in a submarine hydrothermal vent and first described in 2002. Taxonomy Members of the Nanoarchaeota are associated with different host organisms and environmental conditions. Despite small size, a reduced genome and limited respiration, members of the Nanoarchaeota have unusual metabolic features. For example, ''N. equitans'' has a complex and highly developed intercellular communication system. The phylogeny of the Nanoarchaeota is anchored by its only cultured representative, ''Nanoarchaeum equitans'', which clusters in a separate evolutionary group than other archaea, which have recently been reclassified. Further analysis has shown that ''N. equitans'' diverged early on in the evolution of Archaea, as indicated by the 16S rRNA sequence. This suggests that they ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermoproteota
The Thermoproteota are prokaryotes that have been classified as a phylum (biology), 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, Filamentation, filamentous and oddly-shaped cells. Recent evidence shows that some members of the Thermoproteota are methanogens. Thermoproteota were initially classif ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Euryarchaeota
Methanobacteriota is a phylum in the domain Archaea. Taxonomy The phylum ''Methanobacteriota'' was introduced to prokaryotic nomenclature in 2023. It contains following classes: *Archaeoglobi Garrity & Holt (2002) *Halobacteria Grant ''et al.'' (2002) *Methanobacteria Boone (2002) (contains type genus ''Methanobacterium'') *Methanococci Boone (2002) *Methanonatronarchaeia Sorokin ''et al.'' (2018) *Methanopyri Garrity & Holt (2002) *Methanosarcinia Chuvochina ''et al.'' (2024) *Thermococci Zillig & Reysenbach (2002) *Thermoplasmata Reysenbach (2002) References Archaea phyla {{Archaea-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phylum (biology)
In biology, a phylum (; : phyla) is a level of classification, or taxonomic rank, that is below kingdom and above class. Traditionally, in botany the term division has been used instead of phylum, although the International Code of Nomenclature for algae, fungi, and plants accepts the terms as equivalent. Depending on definitions, the animal kingdom Animalia contains about 31 phyla, the plant kingdom Plantae contains about 14 phyla, and the fungus kingdom Fungi contains about eight phyla. Current research in phylogenetics is uncovering the relationships among phyla within larger clades like Ecdysozoa and Embryophyta. General description The term phylum was coined in 1866 by Ernst Haeckel from the Greek (, "race, stock"), related to (, "tribe, clan"). Haeckel noted that species constantly evolved into new species that seemed to retain few consistent features among themselves and therefore few features that distinguished them as a group ("a self-contained unity"): "perhap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archaea
Archaea ( ) is a Domain (biology), domain of organisms. Traditionally, Archaea only included its Prokaryote, prokaryotic members, but this has since been found to be paraphyletic, as eukaryotes are known to have evolved from archaea. Even though the domain Archaea Cladistics, cladistically includes eukaryotes, the term "archaea" (: archaeon , from the Greek "ἀρχαῖον", which means ancient) in English still generally refers specifically to prokaryotic members of Archaea. Archaea were initially Taxonomy (biology), classified as bacteria, receiving the name archaebacteria (, in the Archaebacteria Kingdom (biology), kingdom), but this term has fallen out of use. Archaeal cells have unique properties separating them from Bacteria and Eukaryote, Eukaryota. Archaea are further divided into multiple recognized phylum, phyla. Classification is difficult because most have not been Isolation (microbiology), isolated in a laboratory and have been detected only by their Gene, gene s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ribosomal RNA
Ribosomal ribonucleic acid (rRNA) is a type of non-coding RNA which is the primary component of ribosomes, essential to all cells. rRNA is a ribozyme which carries out protein synthesis in ribosomes. Ribosomal RNA is transcribed from ribosomal DNA (rDNA) and then bound to ribosomal proteins to form SSU rRNA, small and LSU rRNA, large ribosome subunits. rRNA is the physical and mechanical factor of the ribosome that forces transfer RNA (tRNA) and messenger RNA (mRNA) to process and Translation (biology), translate the latter into proteins. Ribosomal RNA is the predominant form of RNA found in most cells; it makes up about 80% of cellular RNA despite never being translated into proteins itself. Ribosomes are composed of approximately 60% rRNA and 40% ribosomal proteins, though this ratio differs between Prokaryote, prokaryotes and Eukaryote, eukaryotes. Structure Although the primary structure of rRNA sequences can vary across organisms, Base pair, base-pairing within these sequ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
16S Ribosomal RNA
16S ribosomal RNA (or 16 S rRNA) is the RNA component of the 30S subunit of a prokaryotic ribosome ( SSU rRNA). It binds to the Shine-Dalgarno sequence and provides most of the SSU structure. The genes coding for it are referred to as 16S rRNA genes and are used in reconstructing phylogenies, due to the slow rates of evolution of this region of the gene. Carl Woese and George E. Fox were two of the people who pioneered the use of 16S rRNA in phylogenetics in 1977. Multiple sequences of the 16S rRNA gene can exist within a single bacterium. Terminology The descriptor ''16S'' refers to the size of these ribosomal subunits as reflected indirectly by the speed at which they sediment when samples are centrifuged. Thus ''16S'' means 16 Svedburg units. Functions * Like the large (23S) ribosomal RNA, it has a structural role, acting as a scaffold defining the positions of the ribosomal proteins. * The 3-end contains the anti- Shine-Dalgarno sequence, which binds upstream ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genome Size
Genome size is the total amount of DNA contained within one copy of a single complete genome. It is typically measured in terms of mass in picograms (trillionths or 10−12 of a gram, abbreviated pg) or less frequently in daltons, or as the total number of nucleotide base pairs, usually in megabases (millions of base pairs, abbreviated Mb or Mbp). One picogram is equal to 978 megabases. In diploid organisms, genome size is often used interchangeably with the term C-value. An organism's complexity is not directly proportional to its genome size; total DNA content is widely variable between biological taxa. Some single-celled organisms have much more DNA than humans, for reasons that remain unclear (see Junk DNA and C-value). Variation in genome size and gene content Since the 1950s, with the emergence of various molecular techniques, the genome sizes of thousands of eukaryotes have been analyzed, and these data are available in online databases for animals, plants, and fung ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mycoplasma Genitalium
''Mycoplasma genitalium'' (also known as ''MG','' Mgen, or since 2018, ''Mycoplasmoides genitalium'') is a sexually transmitted, small and pathogenic bacterium that lives on the mucous epithelial cells of the urinary and genital tracts in humans. Medical reports published in 2007 and 2015 state that Mgen is becoming increasingly common. Resistance to multiple antibiotics, including the macrolide azithromycin, which until recently was the most reliable treatment, is becoming prevalent. The bacterium was first isolated from the urogenital tract of humans in 1981, and was eventually identified as a new species of '' Mycoplasma'' in 1983. It can cause negative health effects in men and women. It also increases the risk for HIV spread with higher occurrences in those previously treated with the azithromycin antibiotics. Symptoms of infection Mgen is a bacterium recognized for causing urethritis in both men and women along with cervicitis and pelvic inflammation in women ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
S-layer
An S-layer (surface layer) is a part of the cell envelope found in almost all archaea, as well as in many types of bacteria. The S-layers of both archaea and bacteria consists of a Monolayer, monomolecular layer composed of only one (or, in a few cases, two) identical proteins or glycoproteins. This structure is built via self-assembly and encloses the whole cell surface. Thus, the S-layer protein can represent up to 15% of the whole protein content of a cell. S-layer proteins are poorly conserved or not conserved at all, and can differ markedly even between related species. Depending on species, the S-layers have a thickness between 5 and 25 nm and possess identical pores 2–8 nm in diameter. The terminology "S-layer" was used the first time in 1976. The general use was accepted at the "First International Workshop on Crystalline Bacterial Cell Surface Layers, Vienna (Austria)" in 1984, and in the year 1987 S-layers were defined at the European Molecular Biology Organiz ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
