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Candidatus Carsonella Ruddii
In prokaryote nomenclature, ''Candidatus'' (Latin for candidate of Roman office) is used to name prokaryotic phyla that are well characterized but yet-uncultured. Contemporary sequencing approaches, such as 16S sequencing or metagenomics, provide much information about the analyzed organisms and thus allow to identify and characterize individual species. However, the majority of prokaryotic species remain uncultivable and hence inaccessible for further characterization in ''in vitro'' study. The recent discoveries of a multitude of candidate taxa has led to candidate phyla radiation expanding the tree of life through the new insights in bacterial diversity. Nomenclature History The initial International Code of Nomenclature of Prokaryotes as well as early revisions did not account for the possibility of identifying prokaryotes which were not yet cultivable. Therefore, the term ''Candidatus'' was proposed in the context of a conference of the International Committee on Systemati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prokaryote
A prokaryote () is a single-celled organism that lacks a nucleus and other membrane-bound organelles. The word ''prokaryote'' comes from the Greek πρό (, 'before') and κάρυον (, 'nut' or 'kernel').Campbell, N. "Biology:Concepts & Connections". Pearson Education. San Francisco: 2003. In the two-empire system arising from the work of Édouard Chatton, prokaryotes were classified within the empire Prokaryota. But in the three-domain system, based upon molecular analysis, prokaryotes are divided into two domains: ''Bacteria'' (formerly Eubacteria) and '' Archaea'' (formerly Archaebacteria). Organisms with nuclei are placed in a third domain, Eukaryota. In the study of the origins of life, prokaryotes are thought to have arisen before eukaryotes. Besides the absence of a nucleus, prokaryotes also lack mitochondria, or most of the other membrane-bound organelles that characterize the eukaryotic cell. It was once thought that prokaryotic cellular components within the c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ectosymbiosis
Ectosymbiosis is a form of symbiotic behavior in which a parasite lives on the body surface of the host, including internal surfaces such as the lining of the digestive tube and the ducts of glands. The parasitic species is generally an immobile, or sessile, organism existing off of biotic substrate through mutualism, commensalism, or parasitism. Ectosymbiosis is found throughout a diverse array of environments and in many different species. In some species the symbiotic environment provided by both the parasite and host are mutually beneficial. In recent research it has been found that these micro-flora will evolve and diversify rapidly in response to a change in the external environment, in order to stabilize and maintain a beneficial ectosymbiotic environment. Evolutionary History Ectosymbiosis has evolved independently many times to fill a wide variety of ecological niches, both temperate and extreme. Such temperate regions include the seas off the coast of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Undescribed Taxon
In taxonomy, an undescribed taxon is a taxon (for example, a species) that has been discovered, but not yet formally described and named. The various Nomenclature Codes specify the requirements for a new taxon to be validly described and named. Until such a description has been published, the taxon has no formal or official name, although a temporary, informal name is often used. A published scientific name may not fulfil the requirements of the Codes for various reasons. For example, if the taxon was not adequately described, its name is called a '' nomen nudum''. It is possible for a taxon to be "undescribed" for an extensive period of time, even if unofficial descriptions are published. An undescribed species may be referred to with the genus name, followed by "sp"., but this abbreviation is also used to label specimens or images that are too incomplete to be identified at the species level. In some cases, there is more than one undescribed species in a genus. In this ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Taxa With Candidatus Status
This is a list of taxa with ''Candidatus'' status. For taxa not covered by this list, see also: * the GenBank taxonomy for "effective" names as published; * the ''Candidatus Lists'' and LPSN for latinate names, some sanitized to match the Code. Phyla * "''Ca.'' Absconditabacteria" (previously Candidate phylum SR1) * ABY1 aka OD1-ABY1, subgroup of OD1 ("''Ca.'' Parcubacteria")Kenly A. Hiller, Kenneth H. Foreman, David Weisman, Jennifer L. Bowen: Permeable Reactive Barriers Designed To Mitigate Eutrophication Alter Bacterial Community Composition and Aquifer Redox Conditions. In: Appl Environ Microbiol v.81(20); 2015 Oct; pp.7114–7124. doi:10.1128/AEM.01986-15. . . * Candidate phylum AC1 * "''Ca.'' Acetothermia" (previously Candidate phylum OP1) * "''Ca.'' Aerophobetes" (previously Candidate phylum CD12 or BHI80-139) * "''Ca.'' Aminicenantes" (previously Candidate phylum OP8) * aquifer1 * aquifer2 * "''Ca.'' Berkelbacteria" (previously Candidate phylum ACD58) * BRC ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Code Of Nomenclature Of Bacteria
The International Code of Nomenclature of Prokaryotes (ICNP) formerly the International Code of Nomenclature of Bacteria (ICNB) or Bacteriological Code (BC) governs the scientific names for Bacteria and Archaea.P. H. A. Sneath, 2003. A short history of the Bacteriological CodURL It denotes the rules for naming taxa of bacteria, according to their relative rank. As such it is one of the nomenclature codes of biology. Originally the ''International Code of Botanical Nomenclature'' dealt with bacteria, and this kept references to bacteria until these were eliminated at the 1975 International Botanical Congress. An early Code for the nomenclature of bacteria was approved at the 4th International Congress for Microbiology in 1947, but was later discarded. The latest version to be printed in book form is the 1990 Revision, but the book does not represent the current rules. The 2008 Revision has been published in the '' International Journal of Systematic and Evolutionary Microbiology'' ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glossary Of Scientific Naming
This is a list of terms and symbols used in scientific names for organisms, and in describing the names. For proper parts of the names themselves, see List of Latin and Greek words commonly used in systematic names. Note that many of the abbreviations are used with or without a stop. Naming standards and taxonomic organizations and their codes and taxonomies * ICTV – International Committee on Taxonomy of Viruses * ICSP – International Committee on Systematics of Prokaryotes ** formerly the ICSB – International Committee on Systematic Bacteriology ** publishes the ICNP – International Code of Nomenclature of Prokaryotes *** formerly the International Code of Nomenclature of Bacteria (ICNB) or Bacteriological Code (BC) * ICZN – International Commission on Zoological Nomenclature ** publishes ''ICZN'' the '' International Code of Zoological Nomenclature'' or "ICZN Code" * IBC – International Botanical Congress ** publishes ''ICN'' the '' International Code of Nomen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transcriptional Regulation
In molecular biology and genetics, transcriptional regulation is the means by which a cell regulates the conversion of DNA to RNA (transcription), thereby orchestrating gene activity. A single gene can be regulated in a range of ways, from altering the number of copies of RNA that are transcribed, to the temporal control of when the gene is transcribed. This control allows the cell or organism to respond to a variety of intra- and extracellular signals and thus mount a response. Some examples of this include producing the mRNA that encode enzymes to adapt to a change in a food source, producing the gene products involved in cell cycle specific activities, and producing the gene products responsible for cellular differentiation in multicellular eukaryotes, as studied in evolutionary developmental biology. The regulation of transcription is a vital process in all living organisms. It is orchestrated by transcription factors and other proteins working in concert to finely tune ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DNA Repair
DNA repair is a collection of processes by which a cell identifies and corrects damage to the DNA molecules that encode its genome. In human cells, both normal metabolic activities and environmental factors such as radiation can cause DNA damage, resulting in tens of thousands of individual molecular lesions per cell per day. Many of these lesions cause structural damage to the DNA molecule and can alter or eliminate the cell's ability to transcribe the gene that the affected DNA encodes. Other lesions induce potentially harmful mutations in the cell's genome, which affect the survival of its daughter cells after it undergoes mitosis. As a consequence, the DNA repair process is constantly active as it responds to damage in the DNA structure. When normal repair processes fail, and when cellular apoptosis does not occur, irreparable DNA damage may occur, including double-strand breaks and DNA crosslinkages (interstrand crosslinks or ICLs). This can eventually lead to malign ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genome Reduction
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 (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 non-coding DNA and C-value enigma). Origin of the term The term "genome size" is often erroneously attributed to a 1976 paper by Ralph Hinegardner, even in discussions dealing specifically with terminology in this area of research (e.g., Greilhuber 2005). Notably, Hinegardner us ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endosymbiont
An ''endosymbiont'' or ''endobiont'' is any organism that lives within the body or cells of another organism most often, though not always, in a mutualistic relationship. (The term endosymbiosis is from the Greek: ἔνδον ''endon'' "within", σύν ''syn'' "together" and βίωσις ''biosis'' "living".) Examples are nitrogen-fixing bacteria (called rhizobia), which live in the root nodules of legumes, single-cell algae inside reef-building corals and bacterial endosymbionts that provide essential nutrients to insects. There are two types of symbiont transmissions. In horizontal transmission, each new generation acquires free living symbionts from the environment. An example is the nitrogen-fixing bacteria in certain plant roots. Vertical transmission takes place when the symbiont is transferred directly from parent to offspring. It is also possible for both to be involved in a mixed-mode transmission, where symbionts are transferred vertically for some generation befor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Symbiosis
Symbiosis (from Greek , , "living together", from , , "together", and , bíōsis, "living") is any type of a close and long-term biological interaction between two different biological organisms, be it mutualistic, commensalistic, or parasitic. The organisms, each termed a symbiont, must be of different species. In 1879, Heinrich Anton de Bary defined it as "the living together of unlike organisms". The term was subject to a century-long debate about whether it should specifically denote mutualism, as in lichens. Biologists have now abandoned that restriction. Symbiosis can be obligatory, which means that one or more of the symbionts depend on each other for survival, or facultative (optional), when they can generally live independently. Symbiosis is also classified by physical attachment. When symbionts form a single body it is called conjunctive symbiosis, while all other arrangements are called disjunctive symbiosis."symbiosis." Dorland's Illustrated Medical Diction ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nomenclature Codes
Nomenclature codes or codes of nomenclature are the various rulebooks that govern biological taxonomic nomenclature, each in their own broad field of organisms. To an end-user who only deals with names of species, with some awareness that species are assignable to families, it may not be noticeable that there is more than one code, but beyond this basic level these are rather different in the way they work. The successful introduction of two-part names for species by Linnaeus was the start for an ever-expanding system of nomenclature. With all naturalists worldwide adopting this approach to thinking up names, there arose several schools of thought about the details. It became ever more apparent that a detailed body of rules was necessary to govern scientific names. From the mid-19th century onwards, there were several initiatives to arrive at worldwide-accepted sets of rules. Presently nomenclature codes govern the naming of: * Algae, Fungi and Plants – '' International C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
