Genus ( / ˈ dʒ iː n ə s / ; pl. : genera / ˈ dʒ ɛ n ər ə / ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses . In binomial nomenclature , the genus name forms the first part of the binomial species name for each species within the genus.
46-411: Sulfolobus is a genus of microorganism in the family Sulfolobaceae . It belongs to the archaea domain. Sulfolobus species grow in volcanic springs with optimal growth occurring at pH 2–3 and temperatures of 75–80 °C, making them acidophiles and thermophiles respectively. Sulfolobus cells are irregularly shaped and flagellar . Species of Sulfolobus are generally named after
92-557: A species : see Botanical name and Specific name (zoology) . The rules for the scientific names of organisms are laid down in the nomenclature codes , which allow each species a single unique name that, for animals (including protists ), plants (also including algae and fungi ) and prokaryotes ( bacteria and archaea ), is Latin and binomial in form; this contrasts with common or vernacular names , which are non-standardized, can be non-unique, and typically also vary by country and language of usage. Except for viruses ,
138-432: A circular chromosome that consists of 2,992,245 bp. Another sequenced species, S. tokodaii has a circular chromosome as well but is slightly smaller with 2,694,756 bp. Both species lack the genes ftsZ and minD, which has been characteristic of sequenced Crenarchaeota. They also code for citrate synthase and two subunits of 2-oxoacid:ferredoxin oxidoreductase, which plays the same role as alpha-ketoglutarate dehydrogenase in
184-492: A glycolytic pathway, a pentose phosphate pathway, and the TCA cycle. All Archaea have lipids with ether links between the head group and side chains, making the lipids more resistant to heat and acidity than bacterial and eukaryotic ester-linked lipids. The Sulfolobales are known for unusual tetraether lipids. In Sulfolobales, the ether-linked lipids are joined covalently across the "bilayer," making tetraethers. Technically, therefore,
230-651: A later homonym of a validly published name is a nomen illegitimum or nom. illeg. ; for a full list refer to the International Code of Nomenclature for algae, fungi, and plants and the work cited above by Hawksworth, 2010. In place of the "valid taxon" in zoology, the nearest equivalent in botany is " correct name " or "current name" which can, again, differ or change with alternative taxonomic treatments or new information that results in previously accepted genera being combined or split. Prokaryote and virus codes of nomenclature also exist which serve as
276-628: A long time and redescribed as new by a range of subsequent workers, or if a range of genera previously considered separate taxa have subsequently been consolidated into one. For example, the World Register of Marine Species presently lists 8 genus-level synonyms for the sperm whale genus Physeter Linnaeus, 1758, and 13 for the bivalve genus Pecten O.F. Müller, 1776. Within the same kingdom, one generic name can apply to one genus only. However, many names have been assigned (usually unintentionally) to two or more different genera. For example,
322-409: A reference for designating currently accepted genus names as opposed to others which may be either reduced to synonymy, or, in the case of prokaryotes, relegated to a status of "names without standing in prokaryotic nomenclature". An available (zoological) or validly published (botanical) name that has been historically applied to a genus but is not regarded as the accepted (current/valid) name for
368-427: A taxon; however, the names published in suppressed works are made unavailable via the relevant Opinion dealing with the work in question. In botany, similar concepts exist but with different labels. The botanical equivalent of zoology's "available name" is a validly published name . An invalidly published name is a nomen invalidum or nom. inval. ; a rejected name is a nomen rejiciendum or nom. rej. ;
414-400: A template. Thus it is thought that the ups system in combination with homologous recombination provide a DNA damage response which rescues Sulfolobales from DNA damaging threats. Lysogenic viruses infect Sulfolobus for protection. The viruses cannot survive in the extremely acidic and hot conditions that Sulfolobus lives in, and so the viruses use Sulfolobus as protection against
460-455: A total of c. 520,000 published names (including synonyms) as at end 2019, increasing at some 2,500 published generic names per year. "Official" registers of taxon names at all ranks, including genera, exist for a few groups only such as viruses and prokaryotes, while for others there are compendia with no "official" standing such as Index Fungorum for fungi, Index Nominum Algarum and AlgaeBase for algae, Index Nominum Genericorum and
506-518: Is also associated with DNA transfer between cells leading to homologous recombinational repair of DNA damage. The ups operon of Sulfolobus species is highly induced by UV irradiation . The pili encoded by this operon are employed in promoting cellular aggregation, which is necessary for subsequent DNA exchange between cells, resulting in homologous recombination . A study of the Sulfolobales acidocaldarius ups operon showed that one of
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#1732772316045552-612: Is discouraged by both the International Code of Zoological Nomenclature and the International Code of Nomenclature for algae, fungi, and plants , there are some five thousand such names in use in more than one kingdom. For instance, A list of generic homonyms (with their authorities), including both available (validly published) and selected unavailable names, has been compiled by the Interim Register of Marine and Nonmarine Genera (IRMNG). The type genus forms
598-422: Is important for an aerobic microorganism like Sulfolobus , it probably uses a different molecule for the same function or has a different pathway. Sulfolobus can grow either lithoautotrophically by oxidizing sulfur, or chemoheterotrophically using sulfur to oxidize simple reduced carbon compounds. Heterotrophic growth has only been observed, however, in the presence of oxygen. The principle metabolic pathways are
644-537: Is now used as a model to study the molecular mechanisms of DNA replication in Archaea. And because the system of DNA replication in Archaea is much simpler than that in Eukaryota, it was suggested that Archaea could be used as a model to study the much more complex DNA replication in Eukaryota. Sulfolobus proteins are of interest for biotechnology and industrial use due to their thermostable nature. One application
690-460: Is somewhat arbitrary. Although all species within a genus are supposed to be "similar", there are no objective criteria for grouping species into genera. There is much debate among zoologists about whether enormous, species-rich genera should be maintained, as it is extremely difficult to come up with identification keys or even character sets that distinguish all species. Hence, many taxonomists argue in favor of breaking down large genera. For instance,
736-474: Is the type species , and the generic name is permanently associated with the type specimen of its type species. Should the specimen turn out to be assignable to another genus, the generic name linked to it becomes a junior synonym and the remaining taxa in the former genus need to be reassessed. In zoological usage, taxonomic names, including those of genera, are classified as "available" or "unavailable". Available names are those published in accordance with
782-447: Is the creation of artificial derivatives from S. acidocaldarius proteins, named affitins . Intracellular proteins are not necessarily stable at low pH however, as Sulfolobus species maintain a significant pH gradient across the outer membrane. Sulfolobales are metabolically dependent on sulfur: heterotrophic or autotrophic , their energy comes from the oxidation of sulfur and/or cellular respiration in which sulfur acts as
828-621: The International Code of Zoological Nomenclature ; the earliest such name for any taxon (for example, a genus) should then be selected as the " valid " (i.e., current or accepted) name for the taxon in question. Consequently, there will be more available names than valid names at any point in time; which names are currently in use depending on the judgement of taxonomists in either combining taxa described under multiple names, or splitting taxa which may bring available names previously treated as synonyms back into use. "Unavailable" names in zoology comprise names that either were not published according to
874-824: The International Plant Names Index for plants in general, and ferns through angiosperms, respectively, and Nomenclator Zoologicus and the Index to Organism Names for zoological names. Totals for both "all names" and estimates for "accepted names" as held in the Interim Register of Marine and Nonmarine Genera (IRMNG) are broken down further in the publication by Rees et al., 2020 cited above. The accepted names estimates are as follows, broken down by kingdom: The cited ranges of uncertainty arise because IRMNG lists "uncertain" names (not researched therein) in addition to known "accepted" names;
920-404: The platypus belongs to the genus Ornithorhynchus although George Shaw named it Platypus in 1799 (these two names are thus synonyms ) . However, the name Platypus had already been given to a group of ambrosia beetles by Johann Friedrich Wilhelm Herbst in 1793. A name that means two different things is a homonym . Since beetles and platypuses are both members of the kingdom Animalia,
966-596: The DNA damaging agents UV-irradiation, bleomycin or mitomycin C induced cellular aggregation. Other physical stressors, such as pH or temperature shift, did not induce aggregation, suggesting that induction of aggregation is caused specifically by DNA damage. Ajon et al. showed that UV-induced cellular aggregation mediates chromosomal marker exchange with high frequency in S. acidocaldarius . Recombination rates exceeded those of uninduced cultures by up to three orders of magnitude. Wood et al. also showed that UV-irradiation increased
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#17327723160451012-473: The French botanist Joseph Pitton de Tournefort (1656–1708) is considered "the founder of the modern concept of genera". The scientific name (or the scientific epithet) of a genus is also called the generic name ; in modern style guides and science, it is always capitalised. It plays a fundamental role in binomial nomenclature , the system of naming organisms , where it is combined with the scientific name of
1058-443: The TCA (tricarboxylic/Krebs/citric acid) cycle. This indicates that Sulfolobus has a TCA cycle system similar to that found in mitochondria of eukaryotes. Other genes in the respiratory chain which partake in the production of ATP were not similar to what is found in eukaryotes. Cytochrome c is one such example that plays an important role in electron transfer to oxygen in eukaryotes. This was also found in A. pernix K1. Since this step
1104-442: The base for higher taxonomic ranks, such as the family name Canidae ("Canids") based on Canis . However, this does not typically ascend more than one or two levels: the order to which dogs and wolves belong is Carnivora ("Carnivores"). The numbers of either accepted, or all published genus names is not known precisely; Rees et al., 2020 estimate that approximately 310,000 accepted names (valid taxa) may exist, out of
1150-1318: The final electron acceptor. For example, S. tokodaii is known to oxidize hydrogen sulfide to sulfate intracellularly. The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) and National Center for Biotechnology Information (NCBI) Acidianus Acidianus brierleyi Metallosphaera Saccharolobus Sulfodiicoccus Sulfuracidifex Sulfolobus acidocaldarius Stygiolobus Sulfurisphaera Sulfodiicoccus Sakai & Kurosawa 2017 Sulfurisphaera Kurosawa et al. 1998 Stygiolobus Segerer et al. 1991 Sulfolobus acidocaldarius Brock et al. 1972 Sulfuracidifex Itoh et al. 2020 Saccharolobus Sakai & Kurosawa 2018 Metallosphaera Huber et al. 1989 Acidianus brierleyi " Ca. Aramenus " Servín-Garcidueñas & Martínez-Romero 2014 Acidianus Segerer et al. 1986 The complete genomes have been sequenced for S. acidocaldarius DSM 639 (2,225,959 nucleotides ), S. solfataricus P2 (2,992,245 nucleotides), and S. tokodaii str. 7 (2,694,756 nucleotides). The archaeon Sulfolobus solfataricus has
1196-446: The form "author, year" in zoology, and "standard abbreviated author name" in botany. Thus in the examples above, the genus Canis would be cited in full as " Canis Linnaeus, 1758" (zoological usage), while Hibiscus , also first established by Linnaeus but in 1753, is simply " Hibiscus L." (botanical usage). Each genus should have a designated type , although in practice there is a backlog of older names without one. In zoology, this
1242-517: The frequency of recombination due to genetic exchange in S. acidocaldarius . Frols et al. and Ajon et al. hypothesized that the UV-inducible DNA transfer process and subsequent homologous recombinational repair represents an important mechanism to maintain chromosome integrity in S. acidocaldarius and S. solfataricus . This response may be a primitive form of sexual interaction, similar to the more well-studied bacterial transformation that
1288-737: The generic name (or its abbreviated form) still forms the leading portion of the scientific name, for example, Canis lupus lupus for the Eurasian wolf subspecies, or as a botanical example, Hibiscus arnottianus ssp. immaculatus . Also, as visible in the above examples, the Latinised portions of the scientific names of genera and their included species (and infraspecies, where applicable) are, by convention, written in italics . The scientific names of virus species are descriptive, not binomial in form, and may or may not incorporate an indication of their containing genus; for example,
1334-406: The genes of the operon, saci-1497 , encodes an endonuclease III that nicks UV-damaged DNA; and another gene of the operon, saci-1500 , encodes a RecQ-like helicase that is able to unwind homologous recombination intermediates such as Holliday junctions . It was proposed that Saci-1497 and Saci-1500 function in an homologous recombination-based DNA repair mechanism that uses transferred DNA as
1380-402: The harsh elements. This relationship allows the virus to replicate inside the archaea without being destroyed by the environment. The Sulfolobus viruses are temperate or permanent lysogens. Permanent lysogens differ from lysogenic bacteriophages in that the host cells are not lysed after the induction of Fuselloviridae production and eventually return to the lysogenic state. They are also unique in
1426-432: The idea that a newly defined genus should fulfill these three criteria to be descriptively useful: Moreover, genera should be composed of phylogenetic units of the same kind as other (analogous) genera. The term "genus" comes from Latin genus , a noun form cognate with gignere ('to bear; to give birth to'). The Swedish taxonomist Carl Linnaeus popularized its use in his 1753 Species Plantarum , but
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1472-633: The largest component, with 23,236 ± 5,379 accepted genus names, of which 20,845 ± 4,494 are angiosperms (superclass Angiospermae). By comparison, the 2018 annual edition of the Catalogue of Life (estimated >90% complete, for extant species in the main) contains currently 175,363 "accepted" genus names for 1,744,204 living and 59,284 extinct species, also including genus names only (no species) for some groups. The number of species in genera varies considerably among taxonomic groups. For instance, among (non-avian) reptiles , which have about 1180 genera,
1518-491: The location from which they were first isolated, e.g. Sulfolobus solfataricus was first isolated in the Solfatara volcano. Other species can be found throughout the world in areas of volcanic or geothermal activity, such as geological formations called mud pots , which are also known as solfatare (plural of solfatara). When the first Archaeal genome, Methanococcus jannaschii , had been sequenced completely in 1996, it
1564-403: The most (>300) have only 1 species, ~360 have between 2 and 4 species, 260 have 5–10 species, ~200 have 11–50 species, and only 27 genera have more than 50 species. However, some insect genera such as the bee genera Lasioglossum and Andrena have over 1000 species each. The largest flowering plant genus, Astragalus , contains over 3,000 species. Which species are assigned to a genus
1610-428: The name could not be used for both. Johann Friedrich Blumenbach published the replacement name Ornithorhynchus in 1800. However, a genus in one kingdom is allowed to bear a scientific name that is in use as a generic name (or the name of a taxon in another rank) in a kingdom that is governed by a different nomenclature code. Names with the same form but applying to different taxa are called "homonyms". Although this
1656-416: The origins of DNA replication of Sulfolobus solfataricus and Sulfolobus acidocaldarius were identified. It showed that both species contained two origins in their genome. This was the first time that more than a single origin of DNA replication had been shown to be used in a prokaryotic cell. The mechanism of DNA replication in archaea is evolutionary conserved, and similar to that of eukaryotes. Sulfolobus
1702-541: The provisions of the ICZN Code, e.g., incorrect original or subsequent spellings, names published only in a thesis, and generic names published after 1930 with no type species indicated. According to "Glossary" section of the zoological Code, suppressed names (per published "Opinions" of the International Commission of Zoological Nomenclature) remain available but cannot be used as the valid name for
1748-624: The sense that the genes encoding the structural proteins of the virus are constantly transcribed and DNA replication appears to be induced. The viruses infecting archaea like Sulfolobus have to use a strategy to escape prolonged direct exposure to the type of environment their host lives in, which may explain some of their unique properties. Genus The composition of a genus is determined by taxonomists . The standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. There are some general practices used, however, including
1794-497: The specific name particular to the wolf. A botanical example would be Hibiscus arnottianus , a particular species of the genus Hibiscus native to Hawaii. The specific name is written in lower-case and may be followed by subspecies names in zoology or a variety of infraspecific names in botany . When the generic name is already known from context, it may be shortened to its initial letter, for example, C. lupus in place of Canis lupus . Where species are further subdivided,
1840-412: The standard format for a species name comprises the generic name, indicating the genus to which the species belongs, followed by the specific epithet, which (within that genus) is unique to the species. For example, the gray wolf 's scientific name is Canis lupus , with Canis ( Latin for 'dog') being the generic name shared by the wolf's close relatives and lupus (Latin for 'wolf') being
1886-403: The taxon is termed a synonym ; some authors also include unavailable names in lists of synonyms as well as available names, such as misspellings, names previously published without fulfilling all of the requirements of the relevant nomenclatural code, and rejected or suppressed names. A particular genus name may have zero to many synonyms, the latter case generally if the genus has been known for
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1932-650: The temperature is about 80 °C with a pH at about 3 and sulfur present. Another species, S. tokodaii , has been located in an acidic spa in Beppu Hot Springs , Kyushu , Japan . Sediments from ~90m below the seafloor on the Peruvian continental margin are dominated by intact archaeal tetraethers, and a significant fraction of the community is sedimentary archaea taxonomically linked to the crenarchaeal Sulfolobales (Sturt, et al. , 2004). Exposure of Sulfolobus solfataricus or Sulfolobus acidocaldarius to
1978-405: The tetraethers form a monolayer, not a bilayer. The tetraethers help Sulfolobus species survive extreme acid as well as high temperature. S. solfataricus has been found in different areas including Yellowstone National Park , Mount St. Helens , Iceland , Italy , and Russia to name a few. Sulfolobus is located almost wherever there is volcanic activity . They thrive in environments where
2024-576: The values quoted are the mean of "accepted" names alone (all "uncertain" names treated as unaccepted) and "accepted + uncertain" names (all "uncertain" names treated as accepted), with the associated range of uncertainty indicating these two extremes. Within Animalia, the largest phylum is Arthropoda , with 151,697 ± 33,160 accepted genus names, of which 114,387 ± 27,654 are insects (class Insecta). Within Plantae, Tracheophyta (vascular plants) make up
2070-429: The virus species " Salmonid herpesvirus 1 ", " Salmonid herpesvirus 2 " and " Salmonid herpesvirus 3 " are all within the genus Salmonivirus ; however, the genus to which the species with the formal names " Everglades virus " and " Ross River virus " are assigned is Alphavirus . As with scientific names at other ranks, in all groups other than viruses, names of genera may be cited with their authorities, typically in
2116-557: Was found that the genes in the genome of Methanococcus jannaschii involved in DNA replication, transcription, and translation were more related to their counterparts in eukaryotes than to those in other prokaryotes. In 2001, the first genome sequence of Sulfolobus , Sulfolobus solfataricus P2, was published. In P2's genome, the genes related to chromosome replication were likewise found to be more related to those in eukaryotes. These genes include DNA polymerase, primase (including two subunits), MCM, CDC6/ORC1, RPA, RPC, and PCNA . In 2004,
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