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Two-domain System
The two-domain system is a biological classification by which all organisms in the tree of life are classified into two domains, Bacteria and Archaea. It emerged from development of knowledge of archaea diversity and challenges the widely accepted three-domain system that classifies life into Bacteria, Archaea, and Eukarya. It was preceded by the eocyte hypothesis of James A. Lake in the 1980s, which was largely superseded by the three-domain system, due to evidence at the time. Better understanding of archaea, especially of their roles in the origin of eukaryotes through symbiogenesis with bacteria, led to the revival of the eocyte hypothesis in the 2000s. The two-domain system became more widely accepted after the discovery of a large kingdom of archaea called Promethearchaeati in 2017, which evidence suggests to be the evolutionary root of eukaryotes, thereby making eukaryotes members of the domain Archaea. While the features of promethearchaea do not completely rule out th ...
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A Novel Representation Of The Tree Of Life
A, or a, is the first letter and the first vowel letter of the Latin alphabet, used in the modern English alphabet, and others worldwide. Its name in English is '' a'' (pronounced ), plural ''aes''. It is similar in shape to the Ancient Greek letter alpha, from which it derives. The uppercase version consists of the two slanting sides of a triangle, crossed in the middle by a horizontal bar. The lowercase version is often written in one of two forms: the double-storey and single-storey . The latter is commonly used in handwriting and fonts based on it, especially fonts intended to be read by children, and is also found in italic type. In English, '' a'' is the indefinite article, with the alternative form ''an''. Name In English, the name of the letter is the ''long A'' sound, pronounced . Its name in most other languages matches the letter's pronunciation in open syllables. History The earliest known ancestor of A is ''aleph''—the first letter of the Phoenician ...
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Pasteur Institute
The Pasteur Institute (, ) is a French non-profit private foundation dedicated to the study of biology, micro-organisms, diseases, and vaccines. It is named after Louis Pasteur, who invented pasteurization and vaccines for anthrax and rabies. The institute was founded on 4 June 1887 and inaugurated on 14 November 1888. For over a century, the Institut Pasteur has researched infectious diseases. This worldwide biomedical research organization based in Paris was the first to isolate HIV, the virus that causes AIDS, in 1983. It has also been responsible for discoveries that have enabled medical science to control diseases such as diphtheria, tetanus, tuberculosis, poliomyelitis, influenza, yellow fever, and Plague (disease), plague. Since 1908, ten Institut Pasteur scientists have been awarded the Nobel Prize for medicine and physiology—the 2008 Nobel Prize in Physiology or Medicine was shared between two Pasteur scientists. History The Institut Pasteur was founded in 1887 by ...
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Ford Doolittle
W. Ford Doolittle (born in November 30, 1941 in Urbana, Illinois) is an evolutionary and molecular biologist. He is a member of the US National Academy of Sciences a Fellow of the Royal Society of Canada, a Fellow of the Royal Society (UK] and of the Norwegian Academy of Science and Letters. He is also the winner of the 2013 Gerhard Herzberg Canada Gold Medal for Science and Engineering, Herzberg Medal of the Natural Sciences and Engineering Research Council of Canada and the 2017 Killam Prize. Doolittle has made significant contributions to the study of cyanobacteria. He found evidence for the endosymbiont origins of chloroplasts, and developed a theoretical basis for the initial evolution of eukaryotes. He has shown the importance of horizontal gene transfer in prokaryotic evolution. , he has been professor emeritus at Dalhousie University in Halifax, Nova Scotia. He received his BA in biochemical sciences from Harvard University in 1963 and his PhD from Stanford Universit ...
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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 ...
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Mark Wheelis
Mark L. Wheelis is an American microbiologist. Wheelis is currently a professor in the College of Biological Sciences, University of California, Davis. Carl Woese and Otto Kandler with Wheelis wrote the important paper '' Towards a natural system of organisms: proposal for the domains Archaea, Bacteria, and Eucarya'' that proposed a change from the Two-empire system of Prokaryotes and Eukaryotes to the Three-domain system of the domains Eukaryota, Bacteria and Archaea. Wheelis's research interests include the history of biological warfare Biological warfare, also known as germ warfare, is the use of biological toxins or Pathogen, infectious agents such as bacteria, viruses, insects, and Fungus, fungi with the intent to kill, harm or incapacitate humans, animals or plants as an .... He co-authored (with Larry Gonick) ''The Cartoon Guide to Genetics'' (1983). Wheelis provided the scientific knowledge and text, while Gonick contributed the illustrations and humor.Larry Gonic ...
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Otto Kandler
Otto Kandler (23 October 1920 in Deggendorf – 29 August 2017 in Munich, Bavaria) was a Germans, German botanist and microbiologist. Until his retirement in 1986 he was professor of botany at the Ludwig Maximilian University of Munich. His most important research topics were photosynthesis, plant carbohydrate metabolism, analysis of the structure of bacterial cell walls (murein/peptidoglycan), the systematics of ''Lactobacillus'', and the chemotaxonomy of plants and microorganisms. He presented the first experimental evidence for the existence of photophosphorylation ''in vivo''. His discovery of the basic differences between the cell walls of bacteria and archaea (up to 1990 called "archaebacteria") convinced him that archaea represent an autonomous group of organisms distinct from bacteria. This was the basis for his cooperation with Carl Woese and made him the founder of research on the ''Archaea'' in Germany. In 1990, together with Woese, he proposed the three Domain (biolo ...
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Halobacteria
Haloarchaea (halophilic archaea, halophilic archaebacteria, halobacteria) are a class (biology), class of prokaryotic archaea under the phylum Euryarchaeota, found in water Saturated and unsaturated compounds, saturated or nearly saturated with salt. 'Halobacteria' are now recognized as archaea rather than bacteria and are one of the largest groups of archaea. The name 'halobacteria' was assigned to this group of organisms before the existence of the Domain (biology), domain Archaea was realized, and while valid according to Taxonomy (biology), taxonomic rules, should be updated. Halophilic archaea are generally referred to as haloarchaea to distinguish them from halophilic bacteria. These Halophile, halophilic microorganisms require high salt concentrations to grow, with most species requiring more than 2M NaCl for growth and survival. They are a distinct evolutionary branch of the Archaea distinguished by the possession of ether-linked lipids and the absence of murein in their ...
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Parakaryon
''Parakaryon myojinensis'', also known as the Myojin parakaryote, is a highly unusual species of single-celled organism known only from a single specimen, described in 2012. It has features of both prokaryotes and eukaryotes but is apparently distinct from either group, making it unique among organisms discovered thus far. It is the sole species in the genus ''Parakaryon''. Etymology The generic name ''Parakaryon'' comes from Greek παρά (''pará'', "beside", "beyond", "near") and κάρυον (''káryon'', "nut", "kernel", "nucleus"), and reflects its distinction from eukaryotes and prokaryotes. The specific name ''myojinensis'' reflects the locality where the only sample was collected: from the bristle of a scale worm collected from hydrothermal vents at Myōjin Knoll (明神海丘, ), about deep in the Pacific Ocean, near Aogashima island, southeast of the Japanese archipelago. The authors explain the full binomial as "next to (eu)karyote from Myojin". Structure '' ...
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University Of California, Los Angeles
The University of California, Los Angeles (UCLA) is a public university, public Land-grant university, land-grant research university in Los Angeles, California, United States. Its academic roots were established in 1881 as a normal school then known as the southern branch of the California State Normal School which later evolved into San Jose State University, San José State University. The branch was transferred to the University of California to become the Southern Branch of the University of California in 1919, making it the second-oldest of the ten-campus University of California system after the University of California, Berkeley. UCLA offers 337 undergraduate and graduate degree programs in a range of disciplines, enrolling about 31,600 undergraduate and 14,300 graduate and professional students annually. It received 174,914 undergraduate applications for Fall 2022, including transfers, the most of any Higher education in the United States, university in the United Stat ...
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Eric Henderson
Eric Charles Henderson (born January 8, 1983) is an American football coach who is the co-defensive coordinator, defensive line coach, and run game coordinator for the USC Trojans of the Big Ten Conference (NCAA). He previously served as an assistant coach for the Los Angeles Rams. Henderson played college football at Georgia Tech as a defensive end and was signed by the Cincinnati Bengals as an undrafted free agent in 2006 and played professionally for six seasons. Playing career College While playing for the Georgia Tech Yellow Jackets, Henderson set a team career record with 59.5 tackles-for-loss (TFL), and he ranks fourth in school history in sacks (25). He had a breakout sophomore season in 2003, starting all 13 games and earning first-team All-Atlantic Coast Conference honors with 11 sacks and 24 TFL. He earned second-team All-ACC nods as both a junior and a senior. As a senior, he led the team with six sacks, despite missing four games with an ankle injury, and caused f ...
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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 ...
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Methanogens
Methanogens are anaerobic archaea that produce methane as a byproduct of their energy metabolism, i.e., catabolism. Methane production, or methanogenesis, is the only biochemical pathway for ATP generation in methanogens. All known methanogens belong exclusively to the domain Archaea, although some bacteria, plants, and animal cells are also known to produce methane. However, the biochemical pathway for methane production in these organisms differs from that in methanogens and does not contribute to ATP formation. Methanogens belong to various phyla within the domain Archaea. Previous studies placed all known methanogens into the superphylum Euryarchaeota. However, recent phylogenomic data have led to their reclassification into several different phyla. Methanogens are common in various anoxic environments, such as marine and freshwater sediments, wetlands, the digestive tracts of animals, wastewater treatment plants, rice paddy soil, and landfills. While some methanogens are ex ...
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