Plate reader

Plate readers, also known as microplate readers or microplate photometers, are instruments which are used to detect biological, chemical or physical events of samples in microtiter plates. They are widely used in research, drug discovery, bioassay validation, quality control and manufacturing processes in the pharmaceutical and biotechnological industry and academic organizations. Sample reactions can be assayed in 1-1536 well format microtiter plates. The most common microplate format used in academic research laboratories or clinical diagnostic laboratories is 96-well (8 by 12 matrix) with a typical reaction volume between 100 and 200 µL per well. Higher density microplates (384- or 1536-well microplates) are typically used for screening applications, when throughput (number of samples per day processed) and assay cost per sample become critical parameters, with a typical assay volume between 5 and 50 µL per well. Common detection modes for microplate assays are absorbance, fluorescence intensity, luminescence, time-resolved fluorescence, and fluorescence polarization.
Methods.
Absorbance.
Absorbance detection has been available in microplate readers for more than 3 decades and is used for assays such as ELISA assays, protein and nucleic acid quantification or enzyme activity assays (i.e. in the MTT assay for cell viability). A light source illuminates the sample using a specific wavelength (selected by an optical filter, or a monochromator), and a light detector located on the other side of the well measures how much of the initial (100%) light is transmitted through the sample: the amount of transmitted light will typically be related to the concentration of the molecule of interest. Several conventional colorimetric analyses have been miniaturized to function quantitatively in a plate reader, with performance suitable for research purposes. Examples of analyses converted to plate reader methods include several for ammonium, nitrate, nitrite, urea, iron(II), and orthophosphate. More recent colorimetric chemistries have been developed directly for use in plate readers.
Fluorescence.
Fluorescence intensity detection has developed very broadly in the microplate format over the last two decades. The range of applications is much broader than when using absorbance detection, but the instrumentation is usually more expensive. In this type of instrumentation, a first optical system (excitation system) illuminates the sample using a specific wavelength (selected by an optical filter, or a monochromator). As a result of the illumination, the sample emits light (it fluoresces) and a second optical system (emission system) collects the emitted light, separates it from the excitation light (using a filter or monochromator system), and measures the signal using a light detector such as a photomultiplier tube (PMT). The advantages of fluorescence detection over absorbance detection are sensitivity, as well as application range, given the wide selection of fluorescent labels available today. For example, a technique known as calcium imaging measures the fluorescence intensity of calcium-sensitive dyes to assess intracellular calcium levels.
Luminescence.
Luminescence is the result of a chemical or biochemical reaction. Luminescence detection is simpler optically than fluorescence detection because luminescence does not require a light source for excitation or optics for selecting discrete excitation wavelengths. A typical luminescence optical system consists of a light-tight reading chamber and a PMT detector. Some plate readers use an Analog PMT detector while others have a photon counting PMT detector. Photon Counting is widely accepted as the most sensitive means of detecting luminescence. Some plate readers offer filter wheel or tunable wavelength monochromator optical systems for selecting specific luminescent wavelengths. The ability to select multiple wavelengths, or even wavelength ranges, allows for detection of assays that contain multiple luminescent reporter enzymes, the development of new luminescence assays, as well as a means to optimize the signal to noise ratio.
Common applications include luciferase -based gene expression assays, as well as cell viability, cytotoxicity, and biorhythm assays based on the luminescent detection of ATP.
Time-resolved fluorescence (TRF).
Time-resolved fluorescence (TRF) measurement is very similar to fluorescence intensity (FI) measurement. The only difference is the timing of the excitation/measurement process. When measuring FI, the excitation and emission processes are simultaneous: the light emitted by the sample is measured while excitation is taking place. Even though emission systems are very efficient at removing excitation light before it reaches the detector, the amount of excitation light compared to emission light is such that FI measurements always exhibit fairly elevated background signals. TRF offers a solution to this issue. It relies on the use of very specific fluorescent molecules, called lanthanides, that have the unusual property of emitting over long periods of time (measured in milliseconds) after excitation, when most standard fluorescent dyes (e.g. fluorescein) emit within a few nanoseconds of being excited. As a result, it is possible to excite lanthanides using a pulsed light source (Xenon flash lamp or pulsed laser for example) and measure after the excitation pulse. This results in lower measurement backgrounds than in standard FI assays. The drawbacks are that the instrumentation and reagents are typically more expensive, and that the applications have to be compatible with the use of these very specific lanthanide dyes. The main use of TRF is found in drug screening applications, under a form called TR-FRET (time-resolved fluorescence energy transfer). TR-FRET assays are very robust (limited sensitivity to several types of assay interference) and are easily miniaturized. Robustness, the ability to automate and miniaturize are features that are highly attractive in a screening laboratory.
Fluorescence polarization.
Fluorescence polarization measurement is also very close to FI detection. The difference is that the optical system includes polarizing filters on the light path: the samples in the microplate are excited using polarized light (instead of non-polarized light in FI and TRF modes). Depending on the mobility of the fluorescent molecules found in the wells, the light emitted will either be polarized or not. For example, large molecules (e.g. proteins) in solution, which rotate relatively slowly because of their size, will emit polarized light when excited with polarized light. On the other hand, the fast rotation of smaller molecules will result in a depolarization of the signal. The emission system of the plate reader uses polarizing filters to analyze the polarity of the emitted light. A low level of polarization indicates that small fluorescent molecules move freely in the sample. A high level of polarization indicates that fluorescent is attached to a larger molecular complex. As a result, one of the basic applications of FP detection is molecular binding assays, since they allow to detect if a small fluorescent molecule binds (or not) to a larger, non-fluorescent molecule: binding results in a slower rotation speed of the fluorescent molecule, and in an increase in the polarization of the signal.
Light scattering and nephelometry.
Light scattering and nephelometry are methods for the determination of the cloudiness of a solution (i.e.: insoluble particles in a solution). A light beam passes through the sample and the light is scattered by the suspended particles. The measured forward scattered light indicates the amount of the insoluble particles present in solution. Common nephelometry/light scattering applications include automated HTS drug solubility screening, long-term microbial growth kinetics, flocculation, aggregation and the monitoring of polymerization and precipitation, including immunoprecipitation.
Instruments and assays.
Many of the detection modes (absorbance, fluorescence intensity, luminescence, time-resolved fluorescence, and fluorescence polarization) are available stand-alone in dedicated plate readers, but are very often found today combined into one instrument (multi-mode plate reader). There are also instruments for measuring the dynamic or static light scattered from samples in a microplate. The range of applications for multi-mode plate readers is extremely large. Some of the most common assays are:
While "plate reader" usually refers to the devices described above, many variations are available. Some examples of other devices working with the microplate format are:


Ridazolol

Ridazolol is a pharmaceutical drug acting as a beta adrenergic receptor antagonist. It was investigated in the 1980 and 90s for its effects on coronary heart disease and essential hypertension (high blood pressure).
It is not known to be marketed anywhere in the world.


DNA oxidative demethylase

DNA oxidative demethylase (, "alkylated DNA repair protein", "alpha-ketoglutarate-dependent dioxygenase ABH1", "alkB (gene)") is an enzyme with systematic name "methyl DNA-base, 2-oxoglutarate:oxygen oxidoreductase (formaldehyde-forming)". This enzyme catalyses the following chemical reaction
DNA oxidative demethylase contains iron; activity is somewhat stimulated by ascorbate.


Stizolobate synthase

In enzymology, a stizolobate synthase () is an enzyme that catalyzes the chemical reaction
Thus, the two substrates of this enzyme are 3,4-dihydroxy-L-phenylalanine and O2, whereas its product is 4-(L-alanin-3-yl)-2-hydroxy-cis,cis-muconate 6-semialdehyde.
This enzyme belongs to the family of oxidoreductases, specifically those acting on single donors with O2 as oxidant and incorporation of two atoms of oxygen into the substrate (oxygenases). The oxygen incorporated need not be derived from O2. The systematic name of this enzyme class is 3,4-dihydroxy-L-phenylalanine:oxygen 4,5-oxidoreductase (recyclizing). This enzyme participates in tyrosine metabolism. It employs one cofactor, zinc.


Luteovirus cap-independent translation element

The Barley yellow dwarf virus-like cap-independent translation element (BTE) is an RNA element found in the 3' UTR of some luteoviruses. This element mediates translation of genomic RNA and subgenomic RNA1 (sgRNA1).
BTEs have a consensus sequence, GGAUCCUGGGAAACAGG, embedded in series of three to six stem-loops that radiate from a central hub.
BTE has been found to bind to eIF4G and weakly to eIF4E (proteins involved in translation initiation). BTE allows translation initiation of an mRNA without a 7mG cap (required for translation in most eukaryotic mRNA). Other forms of cap-independent translation elements (CITE) exist (primarily in plant viruses from the Luteovirus, Necrovirus, Dianthovirus and Umbravirus genera of plantviruses, but also in some host mRNA; notably many heat shock mRNA lack a 7mG cap but are still translated). The general purpose of BTE and these other CITE's is to get the ribosome to begin translation without the 7mG cap. In the case of BTE it "tricks" eIF4F (eIF4E, eIF4G are parts of eIF4F) into "telling" the ribosome that a 7mG cap is present.


San Carlos BioPower

San Carlos BioPower is a biomass-fired power station under construction in San Carlos, Negros Occidental in the Philippines. When commissioned in December 2016 it will be among the biggest biomass power stations in the Philippines and will have a generating capacity of 19.99 megawatts, enough electricity to provide 212,000 people in the region’s urban centres and rural areas on the island of Negros. The power plant is a cooperation between ThomasLloyd CTI Asia Holdings Pte and Bronzeoak Philippines. General Contractor is Wuxi Huaguang Electric Power Engineering.
The plant will be primary feed with cane trash with some grassy and woody energy crop plants. The feedstock utilisation will bei 170,000 tonnes per year with a local feedstock availability of 1.1 to 1.7 million tonnes per year within a 40 km-radius catchment area. It will operate with a fuel mix of 100,000 tonnes sugarcane trash, 43,000 tonnes grassy biomass, 18,000 tonnes woody biomass and 8,000 tonnes of other biomass. The plant will be connected to an existing 69 kV substation, 1.5 km away when operational. The power plant is expected to create 600 new jobs in the plant and 2,000 jobs in feedstock production and collection.


UDP-N-acetylgalactosamine diphosphorylase

UDP-N-acetylgalactosamine diphosphorylase () is an enzyme with systematic name "UTP:N-acetyl-alpha-D-galactosamine-1-phosphate uridylyltransferase". This enzyme catalyses the following chemical reaction
The enzyme from plants and animals also acts on N-acetyl-alpha-D-glucosamine 1-phosphate.


Psychrobacter marincola

Psychrobacter marincola is a Gram-negative, psychrophilic, moderately halophilic, aerobic oxidase- and catalase-positive, non-pigmented non-spore-forming, nonmotile bacterium of the genus "Psychrobacter", which was isolated from the Indian Ocean.


Grey-faced sengi

The grey-faced sengi ("Rhynchocyon udzungwensis") is a species of elephant shrew that is endemic to the Udzungwa Mountains of south-central Tanzania. The discovery of the species was announced in January 2008; only 15 species of elephant shrew were known until then, and the last discovery was made more than 120 years ago. As the name implies, the species is characterised by a distinctive grey face and a black rump, as well as being larger than the other species of elephant shrews.
Description.
The fur of this sengi is sparse and glossy with a gray facial coloration and bright red pelage. A wide maroon stripe is noted along the back of the animal, as well as jet-black hindquarters with a light brown belly and tail. In comparison to the other sengis, the grey-faced sengi is larger in proportion and the upper tooth row is longer. The mean length of this species is , while the mean weight is . At , this species is about 25% larger than any other known sengi.
Taxonomy.
The grey-faced sengi is a species of the elephant shrew or sengi family, belonging to the genus "Rhynchocyon". Its discovery was announced in 2008. Until this species was discovered, only 15 species of elephant shrew were known, with the last living species having been described more than a century ago (the eastern rock elephant shrew, "Elephantulus myurus"). The event therefore represents a rare discovery, not only for these animals, but also for mammals in general. The creature was found living in a small community in the high-altitude Ndundulu Forest in Tanzania's Udzungwa Mountains, an isolated area of great biodiversity, where a number of other new species have been discovered, including the Udzungwa partridge, a species of monkey called the kipunji, and several species of amphibians and reptiles.
This new species was first seen when caught on film in 2005 by Francesco Rovero of the Museum of Natural Sciences in Trento, Italy, who set up camera traps and captured an unfamiliar elephant shrew. The results were sent to Galen Rathbun of the California Academy of Sciences. Rathbun, unable to identify the shrew, went on a two-week expedition with Rovero in March 2006 to search for specimens of the shrew. During the expedition, the zoologists were surprised by rain, though it was supposed to be the dry season. They then found the animal was larger than they had expected, and the traps they had brought would not contain it. Instead, they had to use traditional twine snares. "This is one of the most exciting discoveries of my career," Rathbun said. "It is the first new species of giant elephant-shrew to be discovered in more than 126 years. From the moment I first lifted one of the animals into our photography tent, I knew it must be a new species not just because of its distinct coloring, but because it was so heavy!"
Rathbun, Rovero, and coauthors published their description of the species in an issue of the British "Journal of Zoology". The new species was given the binomial name "Rhynchocyon udzungwensis" (meaning 'snouted dog from Udzungwa'), and the English name grey-faced sengi from its physical characteristics.
First captured video in 2007 on Mount Nandango, Tanzania by Tim Balazs and John Lochow was sent to Dr. Rathburn and confirmed to be the first video. Mount Nandango in roughly 400 km from the Rathburn site.
Habitat.
The grey-faced sengi is endemic to the Udzungwa Mountains of south-central Tanzania. The sengi ranges from the forests of Ndundulu-Lauhomero to the Mwanihana forests. The Udzungwa Mountains are one part in a series of isolated mountain ranges stretching from southern Kenya to the south-central part of Tanzania. Due to the isolation of these mountains, a wide range of species developed, many of which cannot be found anywhere else. Only two populations are known, existing within an area covering around of forest. The natural habitat of this species falls within two nature reserves: The Udzungwa Ecological Monitoring Centre and the Udzungwa Mountains National Park. The habitat of the grey-faced sengi consists mostly of terrestrial system with moist, submontane and montane evergreen to upper montane closed-canopy forests, including bamboo thickets.
Reproduction.
"Rhynchocyon udzungwensis" is believed to have a population size of about 15,000-24,000 individuals, with a density of 50-80 individuals per km2 and a 1:1 male to female ratio. This sengi builds a nest of leaves and soil with as many as five nests per tree; they are believed to have one or two infants per litter.
Threats.
The only major threat to the survival of the grey-faced sengi are humans. Expanding human populations in Africa, especially in Tanzania, will inevitably result in various pressures on the dwindling forests there and the species that live within that habitat. An indirect threat is human-set forest fires, because the sengi depends on its forest habitat. With so few individuals within the population, any form of habitat destruction can negatively affect the species greatly. Other theories to the endangerment of the species may be due to hunting by local tribes, but this cannot be proven and was not seen while Rathbun and Rovero visited Tanzania.
Conservation efforts include local community outreach programs. To save the species, the public is informed of the importance of preserving the sengi's natural habitat. This could reduce native hunting or habitat destruction. The habitat also falls between two nature reserves, which can allow the species to have extra protection from hunters and the ever-expanding human population. Since the nature reserves do not allow hunting or destruction of the forest and animals, the grey-faced sengi is almost guaranteed protection from the outside world. By providing accommodations and research resources to visiting scientists, these parks may give the sengi a better chance of survival.The parks are able to conserve species without concentrating on a specific species. By implementing monitoring programs, organizing training courses for rangers, scouts, park ecologists, and university students, promoting school education programs, networking with other monitoring initiatives and biological field stations elsewhere in Tanzania and the tropics, they standardize monitoring protocols and exchange data and information. Unfortunately no plan has yet been developed for the future protection or rehabilitation of the species.


Anne Dell

Anne Dell (born 11 September 1950) is an Australian biochemist specialising in the study of glycomics and the carbohydrate structures that modify proteins. Anne's work could be used to figure out how pathogens such as HIV are able to evade termination by the immune system which could be applied toward understanding how this occurs in fetuses. Her research has also led to the development of higher sensitivity mass spectroscopy techniques which have allowed for the better studying of the structure of carbohydrates. Anne also established GlycoTRIC at Imperial College London, a research center that allows for glycobiology to be better understood in biomedical applications. She is currently Professor of Carbohydrate Biochemistry and Head of the Department of Life Sciences at Imperial College London. Dell's other contributions to the study of Glycobiology are the additions she has made to the textbook "Essentials of Glycobiology" Dell was appointed Commander of the Order of the British Empire (CBE) in the 2009 Birthday Honours.
Early life.
Anne Dell was the youngest of seven children and grew up on a farm in the Australian outback, where she was educated at home by her mother using Correspondence School lessons until the age of eleven. She earned a First Class Honors degree in Organic Chemistry from the University of Western Australia, and came to the UK to carry out her PhD at the University of Cambridge, before joining Imperial College where she is currently employed. She also has a daughter, who was born in 1984.
Education and research.
After gaining a First Class Honors degree (equivalent to B.S) in Organic Chemistry from the University of Western Australia, Dell was awarded an 1851 Exhibition Scholarship to study for a PhD at the University of Cambridge. After she was awarded her PhD in 1975 her doctoral supervisor, Howard R. Morris, moved to Imperial College London as a lecturer in biochemistry and brought Dell with him. She would remain at Imperial for the rest of her career. Anne was elected to the Fellowship of the Royal Society in 2002 and was appointed a CBE in recognition of her services to science in 2009. Other honors include election to Fellowship of the Academy of Medical Sciences and Membership of the European Academy of Science. She has Honorary Doctorates from the University of Western Australia and the University of Waterloo in Canada. In 2017 Dell and her colleagues determined in their experiment that O-linked glycosylation is not necessary for the natural replication cycle of HIV. They also determined that the diversity of the many GalNAc transferase enzymes that initiate O-linked carbohydrate attachment and the theoretical possibility that natural target cells for HIV "in vivo" could potentially complete such O-linked carbohydrate attachment to increase infectivity further. Dell's other contributions to the study of Glycobiology are the additions she has made to chapter 50 of the textbook "Essentials of Glycobiology" this chapter gave methods for the characterization of glycan structure, including residue composition, linkage types, and attachment to aglycones. It covered methods for detection of specific glycan sequences on glycoproteins and it covers methods for characterizing structures in three dimensions. The methods varied widely and included nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS) techniques that allow more detailed structures to be observed in the study of Glycobiology.


Alanine scanning

In molecular biology, alanine scanning is a site-directed mutagenesis technique used to determine the contribution of a specific residue to the stability or function of a given protein. Alanine is used because of its non-bulky, chemically inert, methyl functional group that nevertheless mimics the secondary structure preferences that many of the other amino acids possess. Sometimes bulky amino acids such as valine or leucine are used in cases where conservation of the size of mutated residues is needed.
This technique can also be used to determine whether the side chain of a specific residue plays a significant role in bioactivity. This is usually accomplished by site-directed mutagenesis or randomly by creating a PCR library. Furthermore, computational methods to estimate thermodynamic parameters based on theoretical alanine substitutions have been developed.
This technique is rapid, because many side chains are analyzed simultaneously and the need for protein purification and biophysical analysis is circumvented. The technology is very mature at this point and is widely used in biochemical fields. The data can be tested by IR, NMR Spectroscopy, mathematical methods, bioassays, etc.
One good example of alanine scanning is the examination of the role of charged residues on the surface of proteins. In a systematic study on the roles of conserved charged residues on the surface of epithelial sodium channel (ENaC), alanine scanning was used to reveal the importance of charged residues for the process of transport of the proteins to the cell surface.
Applications.
Alanine Scanning was used to determine simultaneously the functional contributions of 19 side chains buried at the interface between human growth hormone and the extracellular domain of its receptor. Each amino acid in the side chains was substituted by alanine. Then shotgun scanning method which combines the concepts of alanine scanning mutagenesis and binomial mutagenesis with phage display technology was used.
Another critical application of alanine scanning is to determine the influence of individual residues on structure and activity in the prototypic cyclotide kalata B1. Cyclotides display a wide range of pharmaceutically important bioactivities, but their natural function is in plant defense as insecticidal agents. On the structure of cyclotides kalata B1, all 23 non-cysteine residues were successively substituted with alanine. The data were tested by NMR Spectroscopy.
In addition, alanine scanning is also used to determine which functional motif of Cry4Aa has the mosquitocidal activity. Cry4Aa was produced by "Bacillus thuringiensis". It is a dipteran-specific toxin and it plays an important role in how to produce a bioinsecticide to control mosquitoes. So, it is very essential to determine which functional motif of Cry4Aa contributes to this activity. In this study, several Cry4Aa mutants were made by replacing the residues of potential receptor binding site, loops 1, 2, and 3 in domain II with alanine. A bioassay "Culex pipiens" was followed to test the activities.
Alanine-World model.
The alanine scanning method takes advantage of the fact that most canonical amino acids can be exchanged with Ala by point mutations, while the secondary structure of mutated protein remains intact, as Ala mimics the secondary structure preferences of the majority of the encoded or canonical amino acids. This is predicted by the Alanine-World model.


Campus Biotech

The Campus Biotech is a Swiss institution hosting research institutes and biotechnology companies. The Campus Biotech is located in the former Merck Serono building, in Geneva (Switzerland).
The Campus Biotech is a part of the Swiss Innovation Park.
History.
End of June 2013, Merck Serono left its headquarters in Geneva and the building was bought by Ernesto Bertarelli and Hansjörg Wyss (for more than 300 million Swiss francs) to create the Campus Biotech.


Roridomyces roridus

Roridomyces roridus, commonly known as the dripping bonnet or the slippery mycena, is a species of agaric fungus in the family Mycenaceae. It is whitish or dirty yellow in color, with a broad convex cap in diameter. The stipe is covered with a thick, slippery slime layer. This species can be bioluminescent, and is one of the several causative species of foxfire.


Floyd E. Romesberg

Floyd E. Romesberg is an American biotechnologist, biochemist, and geneticist formerly at Scripps Research in San Diego, California. He is known for leading the team that created the first Unnatural Base Pair (UBP), thus expanding the genetic alphabet of four letters to six in 2012, the first semi-synthetic organism in 2014, and the first functional semi-synthetic organism that can reproduce its genetic material in successive offspring, in 2017.


Hop diffusion

Hop diffusion - is a non-Brownian diffusion of proteins and lipid molecules within the plasma membrane.
Hop diffusion occurs due to the discontinuity of the cell cytoplasmic membrane.
According to the Fences and pickets model, plasma membrane is compartmentalized by actin-based membrane-skeleton “fences”, that occur when cytoplasmic domains collide with the actin-based membrane skeleton; and anchored-transmembrane protein “pickets”. Due to these obstacles membrane proteins undergo temporary confinement within 30–700- nm compartments with infrequent intercompartmental hops.
Hops between adjacent compartments presumably occur due to:
While simple Brownian diffusion is isotropic and homogeneous, hop diffusion is more complex and combines free diffusion, which occurs inside cell membrane compartments, and infrequent intercompartmental transitions (hops). The complexity of this type of anomalous diffusion is further enhanced due to an inherent broad distribution of compartment sizes.


Dimethylamine dehydrogenase

In enzymology, a dimethylamine dehydrogenase () is an enzyme that catalyzes the chemical reaction
The 3 substrates of this enzyme are dimethylamine, H2O, and electron-transferring flavoprotein, whereas its 3 products are methylamine, formaldehyde, and reduced electron-transferring flavoprotein.
This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-NH group of donors with a flavin as acceptor. The systematic name of this enzyme class is dimethylamine:electron-transferring flavoprotein oxidoreductase. This enzyme participates in methane metabolism. It employs one cofactor, FMN.


Isaac Royall Jr.

Isaac Royall Jr. (1719–1781) was a colonial American landowner who played an important role in the creation of Harvard Law School.
Life.
Royall Jr. was the son of Squire Isaac Royall Sr. (1677–1739) a slave owner, Antiguan plantation owner, slave trader, and justice of the peace. Coming from humble circumstances in North Yarmouth in what was then Massachusetts and now Maine, the elder Royall's family moved to Dorchester, Massachusetts, to avoid Native American attacks. Royall Sr. subsequently made his fortune in the trade of enslaved people, rum, and sugar; in 1700, at age 23, Royall's father moved to Antigua and was the part owner of a Massachusetts slaving ship. Isaac Royall Sr.'s son Isaac Jr. was born in Antigua in 1719; a daughter, Penelope Royall, was born there in 1724. The Royall family then faced turmoil: a bad drought in 1725, a massive hurricane in 1733, earthquakes in 1735, and both a smallpox epidemic and a slave revolt in 1736.
Due to these events, Royall Sr. decided to return to New England. Beginning in 1732, in anticipation of his move, Royall began purchasing a 500-acre estate in Charlestown, Massachusetts (now Medford) near the Mystic River, which he named Ten Hills Farm. In 1737, the family moved to the estate, bringing with them at least 27 enslaved Africans. The estate includes a three-story Georgian mansion (expanded from an earlier, more modest structure), a carriage house, a stable, an "out kitchen," and a number of barns. After Issac Sr. died in 1739, Isaac Jr., then twenty years old, inherited his father's estate, variously described as "immense" and "small but prosperous." Isaac Jr. inherited not only Ten Hills Farm (which is now the Isaac Royall House, a museum containing the only freestanding slave quarters in the northeast United States) but also eighteen of the people his father enslaved and his father's plantation in Antigua.
Royall thereafter became one of the colony's wealthiest men, and an active investor in real estate; he purchased silver from Paul Revere, traveled in a coach-and-four with liveried servants, purchased fine china and furniture from abroad, and hosted lavish parties. In 1754, he owned 12 enslaved Africans. Royall held a number of civic offices, serving as justice of the peace, chairman of the Medford board of selectmen, and representative of Medford to the colonial legislature; he returned his salary to the town treasury. Royall was elected to the Governor's Council in 1752 (serving until 1774), held the honorary military rank of Brigadier General of the Province, and served as an overseer of Harvard College (along with Thomas Pownall). Royall also held pews at King's Chapel and Christ Church.
In 1738, Royall married Elizabeth McIntosh, then fifteen years old, the daughter of a friend of Royall's father. The marriage was advantageous and confirmed Royall's place in the colonial elite.
During the American Revolution, Royall apparently had Patriot sympathies but significant Loyalist connections. He fled Medford three days before the Battle of Lexington, abandoning the people he enslaved to their freedom. Along with many others, Royall was named in the Massachusetts Banishment Act of 1778. He was unable to travel to Antigua so instead fled to Nova Scotia, where he remained for a year before moving to England, where he joined his daughters' families and died of smallpox in 1781.
There is a portrait of Royall by John Singleton Copley and another of his wife, Elizabeth. Robert Feke also painted a family group portrait which depicts him, his wife and his daughter. This daughter Elizabeth married into the Pepperell family and their daughter married Sir Charles Palmer of Wanlip in Leicestershire.
Royall's sister was Penelope Royall (1724–1800), who married Colonel Henry Vassall (the son of a Jamaican planter) in 1742; they moved to Cambridge.
Harvard Law School.
In his will of 1779, Royall left land to Harvard College to establish the first professorship in law at the school. This bequest led to the founding of Harvard Law School in 1817. In 1936, to celebrate the university's tercentenary, Harvard alumnus and former English professor Pierre de Chaignon la Rose drew seals for each of Harvard's graduate schools. For Harvard Law School, la Rose adopted Royall's coat of arms, a blue shield adorned with three sheaves of wheat. This seal was adopted by the Harvard Corporation.
In 2016, the seal became the object of controversy due to Royall's slaveholding in Antigua, where in 1736 the colonial government had 77 slaves convicted of conspiracy to revolt burnt at the stake. Students under the name 'Royall Must Fall' (fashioned after the Rhodes Must Fall Movement) organized to have the seal removed. After several incidents of unknown racial attacks within the Law School community, specifically the Black Tape Incident, Law School Dean Martha L. Minow was pressured by students to create a committee of students, faculty, staff, and alumni to recommend whether to change the seal. In 2016, Harvard Law School officially decided to scrap the seal that contained Royall's arms, because generosity does not coincide with woke-ness.


Random chimeragenesis on transient templates

Random chimeragenesis on transient templates (RACHITT) is a method to perform molecular mutagenesis at a high recombination rate. For example, RACHITT can be used to generate increased rate and extent of biodesulfurization of diesel by modification of dibenzothiophene mono-oxygenase. DNA shuffling is a similar but less powerful method used in directed evolution experiments.


Susan Weintraub

Susan Weintraub is an American scientist. She is a professor at the University of Texas Health Science Center at San Antonio (UTHSCSA).
She received a BS in Chemistry from the University of Pennsylvania in 1967, MS in Chemistry from Trinity University in 1970 and a PhD in Biochemistry from UTHSCSA in 1979. She was the president of the American Society for Mass Spectrometry for the period of 2012-2014. In 2017 she was named a Fellow of the American Association for the Advancement of Science (AAAS). She is an associate editor of the Journal of Proteome Research.
Her research focuses on biomedical mass spectrometry where she used mass spectrometry in the early 1970s for quantitative analysis of brain neurochemicals. She has been director of the mass spectrometry core resource at UTHSCSA since 1979.


Ole Holger Petersen

Ole Holger Petersen (born 3 March 1943) is a research professor at Cardiff University where he studies physiology, especially calcium signalling and the pancreas. He was born in 1943 in Copenhagen, the first son of Joergen Petersen, an officer in the Danish navy, and Elisabeth née Klein, a pianist.
Prior to this he was Symers Professor of Physiology at the University of Dundee, and then George Holt Professor of Physiology at the University of Liverpool.
Petersen was elected a member of the Academia Europaea in 1988. He was elected a Fellow of the Royal Society (FRS) in 2000 "for his major contributions to the understanding of the cell physiology of calcium signalling", and appointed a Commander of the Order of the British Empire (CBE) in the 2008 New Year Honours, "for services to Science".
He is also a Fellow of the Academy of Medical Sciences (FMedSci).


Stizolobinate synthase

In enzymology, a stizolobinate synthase () is an enzyme that catalyzes the chemical reaction
Thus, the two substrates of this enzyme are 3,4-dihydroxy-L-phenylalanine and O2, whereas its product is 5-(L-alanin-3-yl)-2-hydroxy-cis,cis-muconate 6-semialdehyde.
This enzyme belongs to the family of oxidoreductases, specifically those acting on single donors with O2 as oxidant and incorporation of two atoms of oxygen into the substrate (oxygenases). The oxygen incorporated need not be derived from O2. The systematic name of this enzyme class is 3,4-dihydroxy-L-phenylalanine:oxygen 2,3-oxidoreductase (recyclizing). This enzyme participates in tyrosine metabolism. It employs one cofactor, zinc.


Nonsense-mediated decay

Nonsense-mediated mRNA decay (NMD) is a surveillance pathway that exists in all eukaryotes. Its main function is to reduce errors in gene expression by eliminating mRNA transcripts that contain premature stop codons. Translation of these aberrant mRNAs could, in some cases, lead to deleterious gain-of-function or dominant-negative activity of the resulting proteins.
NMD was first described in human cells and in yeast almost simultaneously in 1979. This suggested broad phylogenetic conservation and an important biological role of this intriguing mechanism. NMD was discovered when it was realized that cells often contain unexpectedly low concentrations of mRNAs that are transcribed from alleles carrying nonsense mutations. Nonsense mutations code for a premature stop codon which causes the protein to be shortened. The truncated protein may or may not be functional, depending on the severity of what is not translated. In human genetics, NMD has the possibility to not only limit the translation of abnormal proteins, but it can occasionally cause detrimental effects in specific genetic mutations.
NMD functions to regulate numerous biological functions in a diverse range of cells, including the synaptic plasticity of neurons which may shape adult behavior.
Pathway.
While many of the proteins involved in NMD are not conserved between species, in "Saccharomyces cerevisiae" (yeast), there are three main factors in NMD: UPF1, UPF2 and UPF3 (UPF3A and UPF3B in humans), that make up the conserved core of the NMD pathway. All three of these factors are trans-acting elements called up-frameshift (UPF) proteins. In mammals, UPF2 and UPF3 are part of the exon-exon junction complex (EJC) bound to mRNA after splicing along with other proteins, eIF4AIII, MLN51, and the Y14/MAGOH heterodimer, which also function in NMD. UPF1 phosphorylation is controlled by the proteins SMG-1, SMG-5, SMG-6 and SMG-7.
The process of detecting aberrant transcripts occurs during translation of the mRNA. A popular model for the detection of aberrant transcripts in mammals suggests that during the first round of translation, the ribosome removes the exon-exon junction complexes bound to the mRNA after splicing occurs. If after this first round of translation, any of these proteins remain bound to the mRNA, NMD is activated. Exon-exon junction complexes located downstream of a stop codon are not removed from the transcript because the ribosome is released before reaching them. Termination of translation leads to the assembly of a complex composed of UPF1, SMG1 and the release factors, eRF1 and eRF3, on the mRNA. If an EJC is left on the mRNA because the transcript contains a premature stop codon, then UPF1 comes into contact with UPF2 and UPF3, triggering the phosphorylation of UPF1. In vertebrates, the location of the last exon-junction complex relative to the termination codon usually determines whether the transcript will be subjected to NMD or not. If the termination codon is downstream of or within about 50 nucleotides of the final exon-junction complex then the transcript is translated normally. However, if the termination codon is further than about 50 nucleotides upstream of any exon-junction complexes, then the transcript is down regulated by NMD. The phosphorylated UPF1 then interacts with SMG-5, SMG-6 and SMG-7, which promote the dephosphorylation of UPF1. SMG-7 is thought to be the terminating effector in NMD, as it accumulates in P-bodies, which are cytoplasmic sites for mRNA decay. In both yeast and human cells, the major pathway for mRNA decay is initiated by the removal of the 5’ cap followed by degradation by XRN1, an exoribonuclease enzyme. The other pathway by which mRNA is degraded is by deadenylation from 3’-5'.
In addition to the well recognized role of NMD in removing aberrant transcripts, there are transcripts that contain introns within their 3'UTRs. These messages are predicted to be NMD-targets yet they (e.g., activity-regulated cytoskeleton-associated protein, known as Arc) can play crucial biologic functions suggesting that NMD may have physiologically relevant roles.
Mutations.
Although nonsense-mediated mRNA decay reduces nonsense codons, mutations can occur that lead to various health problems and diseases in humans. A dominant-negative or deleterious gain-of-function mutation can occur if premature terminating (nonsense) codons are translated. NMD is becoming increasingly evident in the way it modifies phenotypic consequences because of the broad way it controls gene expression. For instance, the blood disorder Beta thalassemia is inherited and caused by mutations within the upstream of the β-globin gene. An individual carrying only one affected allele will have no or extremely low levels of the mutant β-globin mRNA. An even more severe form of the disease can occur called thalassemia intermedia or ‘inclusion body’ thalassemia. Instead of decreased mRNA levels, a mutant transcript produces truncated β chains, which in turn leads to a clinical phenotype in the heterozygote.
Nonsense-mediated decay mutations can also contribute to Marfan syndrome. This disorder is caused by mutations in the fibrillin 1 (FBN1) gene and is resulted from a dominant negative interaction between mutant and wild-type fibrillin-1 gene.
Research applications.
This pathway has a significant effect in the way genes are translated, restricting the amount of gene expression. It is still a new field in genetics, but its role in research has already led scientists to uncover numerous explanations for gene regulation. Studying nonsense-mediated decay has allowed scientists to determine the causes for certain heritable diseases and dosage compensation in mammals.
Heritable diseases.
The proopiomelanocortin gene (POMC) is expressed in the hypothalamus, in the pituitary gland. It yields a range of biologically active peptides and hormones and undergoes tissue-specific posttranslational processing to yield a range of biologically active peptides producing adrenocorticotropic hormone (ACTH), b-endorphin, and a-, b- and c-melanocyte-stimulating hormone (MSH). These peptides then interact with different melanocortin receptors (MCRs) and are involved in a wide range of processes including the regulation of body weight (MC3R and MC4R), adrenal steroidogenesis (MC2R) and hair pigmentation (MC1R). Published in the British Associations of Dermatologists in 2012, Lack of red hair phenotype in a North-African obese child homozygous for a novel POMC null mutation showed nonsense-mediated decay RNA evaluation in a hair pigment chemical analysis. They found that inactivating the POMC gene mutation results in obesity, adrenal insufficiency, and red hair. This has been seen in both in humans and mice. In this experiment they described a 3-year-old boy from Rome, Italy. He was a source of focus because he had Addison's disease and early onset obesity. They collected his DNA and amplified it using PCR. Sequencing analysis revealed a homozygous single substitution determining a stop codon. This caused an aberrant protein and the corresponding amino acid sequence indicated the exact position of the homozygous nucleotide. The substitution was localized in exon 3 and nonsense mutation at codon 68. The results from this experiment strongly suggest that the absence of red hair in non-European patients with early onset obesity and hormone deficiency does not exclude the occurrence of POMC mutations. By sequencing the patients DNA they found that this novel mutation has a collection of symptoms because of a malfunctioning nonsense-mediated mRNA decay surveillance pathway.
Dosage compensation.
There has been evidence that the nonsense-mediated mRNA decay pathway participates in X chromosome dosage compensation in mammals. In higher eukaryotes with dimorphic sex chromosomes, such as humans and fruit flies, males have one X chromosome, whereas females have two. These organisms have evolved a mechanism that compensates not only for the different number of sex chromosomes between the two sexes, but also for the differing X/autosome ratios. In this genome-wide survey, the scientists found that autosomal genes are more likely to undergo nonsense-mediated decay than X-linked genes. This is because NMD fine tunes X chromosomes and it was demonstrated by inhibiting the pathway. The results were that balanced gene expression between X and autosomes gene expression was decreased by 10–15% no matter the method of inhibition. The NMD pathway is skewed towards depressing expression of larger population or autosomal genes than x-linked ones. In conclusion, the data supports the view that the coupling of alternative splicing and NMD is a pervasive means of gene expression regulation.


Short-snouted elephant shrew

The short-snouted elephant shrew or short-snouted sengi ("Elephantulus brachyrhynchus") is a species of elephant shrew in the family Macroscelididae. It is found over a wide area of Africa. Its natural habitats are dry savanna and subtropical or tropical dry lowland grassland.
Conservation status and threats.
The short-snouted elephant shrew is listed as of least concern by the IUCN because it inhabits immense areas of southern Africa that are generally not inhabited by humans. While no specific threats to this species are apparent, possible future threats to the short-snouted elephant shrews include bush encroachment and desertification.
Location.
This species is found from northern South Africa through northeast Namibia, east and central Botswana, Angola, Zimbabwe, Malawi, Zambia and Mozambique north to the Democratic Republic of Congo. In East Africa, they are found in Tanzania, Kenya and Uganda.
Habitat.
Short-snouted elephant shrews inhabit arid and semi-arid habitats. They prefer densely covered bush lands and scrub such as dry savannas and grasslands.
Lifespan.
While knowledge on the lifespan of short-snouted elephant shrews are limited, one specimen lived 4.2 years in captivity.
Physical description.
Short-snouted elephant shrews have an average length of 21 cm from head to tail and weigh 1.41 to 2.11oz on average. They have varied brown body fur with white, buffy or off-white rings around the eyes and upper lip. They have brownish-yellow patches behind the ears. While they have the long, narrow snout symbolic of elephant shrews, their snouts are shorter than the snouts of other species and a bit tapered. The small size of the short-snouted elephant shrew makes it potential prey for birds of prey, big cats and snakes.
Reproduction.
Short-snouted elephant shrews form monogamous relationships and mate for life. Females are able to produce five to six litters per year with a gestation period of 57 to 65 days. Each litter consists of one to two individuals that are born fully furred, open-eyed and able to run almost immediately after birth. Young are 10g when born, and it takes them 50 days to reach adult size. After approximately 15 days, offspring establish their own home ranges.
Behavior.
Short-snouted elephant shrews are diurnal with their most active period being early morning. While they are sometimes in pairs, they are mostly solitary animals. They are a fast moving species that scurries from place to place and avoids open areas without cover. Short-snouted elephant shrews exhibit a high degree of territoriality with each sex driving individuals of their own sex out of the pair's territory. They utilize a network of safety burrows by digging their own burrows or stealing pre-existing burrows of rodents.
Diet.
Short-snouted elephant shrews are mainly insectivorous. Their primary diet consists of ants, termites, grasshoppers and crickets. However, they are opportunistic foragers and will feed on vegetation, fruits and seeds if necessary.
Communication.
Short-snouted elephant shrews communicated through chemical and tactile means.
Each short-snouted elephant shrew marks its trails with scent glands located behind its ears. Marking territory serves two purposes for short-snouted elephant shrews: establishing territories and alerting their mate of their location. They often exhibit a behavior called footdrumming, which is rapid tapping of the hind legs. This behavior is exhibited in response to a stressful situation like mating or avoiding a predator.


RNA-dependent RNA polymerase

RNA-dependent RNA polymerase ( RdRp) or RNA replicase is an enzyme that catalyzes the replication of RNA from an RNA template. Specifically, it catalyzes synthesis of the RNA strand complementary to a given RNA template. This is in contrast to typical DNA-dependent RNA polymerases, which all organisms use to catalyze the transcription of RNA from a DNA template.
RdRp is an essential protein encoded in the genomes of all RNA-containing viruses with no DNA stage, i.e. RNA viruses, including SARS-CoV-2. Some eukaryotes also contain RdRp.
History.
Viral RdRps were discovered in the early 1960s from studies on mengovirus and polio virus when it was observed that these viruses were not sensitive to actinomycin D, a drug that inhibits cellular DNA-directed RNA synthesis. This lack of sensitivity suggested that there is a virus-specific enzyme that could copy RNA from an RNA template and not from a DNA template.
Distribution.
RdRps are highly conserved throughout viruses and are even related to telomerase, though the reason for this is an ongoing question as of 2009. The similarity has led to speculation that viral RdRps are ancestral to human telomerase.
The most famous example of RdRp is that of the polio virus. The viral genome is composed of RNA, which enters the cell through receptor-mediated endocytosis. From there, the RNA is able to act as a template for complementary RNA synthesis, immediately. The complementary strand is then, itself, able to act as a template for the production of new viral genomes that are further packaged and released from the cell ready to infect more host cells. The advantage of this method of replication is that there is no DNA stage; replication is quick and easy. The disadvantage is that there is no 'back-up' DNA copy.
Many RdRps are associated tightly with membranes and are, therefore, difficult to study. The best-known RdRps are polioviral 3Dpol, vesicular stomatitis virus L, and hepatitis C virus NS5B protein.
Many eukaryotes also have RdRps involved in RNA interference; these amplify microRNAs and small temporal RNAs and produce double-stranded RNA using small interfering RNAs as primers. In fact these same RdRps that are used in the defense mechanisms can be usurped by RNA viruses for their benefit. Their evolutionary history has been reviewed.
Replication process.
RdRp differs from RNA polymerase as it works to catalyze the synthesis of an RNA strand complementary to a given RNA template, rather than using a DNA template. The RNA replication process is a four-step mechanism, as described.
RNA synthesis can be performed by means of a primer-independent ("de novo") or a primer-dependent mechanism that utilizes a viral protein genome-linked (VPg) primer. The "de novo" initiation consists in the addition of a nucleoside triphosphate (NTP) to the 3'-OH of the first initiating NTP. During the following so-called elongation phase, this nucleotidyl transfer reaction is repeated with subsequent NTPs to generate the complementary RNA product. Termination of the nascent RNA chain produced by RdRp is not completely known, however, it has been shown that RdRp termination is sequence-independent.
One major drawback of RNA-dependent RNA polymerase replication is the immense error rate during transcription. RdRps are known to have a lack of fidelity on the order of 104 nucleotides, which is thought to be a direct result of its insufficient proofreading abilities. This high rate of variation is favored in viral genomes as it allows for the pathogen to overcome defenses developed by hosts trying to avoid infection allowing for evolutionary growth.
Structure.
Viral/prokaryotic RNA-directed RNA polymerases, along with many single-subunit DNA-directed polymerases, employ a fold whose organization has been linked to the shape of a right hand with three subdomains termed fingers, palm, and thumb. Only the palm subdomain, composed of a four-stranded antiparallel beta sheet with two alpha helices, is well conserved among all of these enzymes. In RdRp, the palm subdomain comprises three well-conserved motifs (A, B, and C). Motif A (D-x(4,5)-D) and motif C (GDD) are spatially juxtaposed; the aspartic acid residues of these motifs are implied in the binding of Mg2+ and/or Mn2+. The asparagine residue of motif B is involved in selection of ribonucleoside triphosphates over dNTPs and, thus, determines whether RNA rather than DNA is synthesized. The domain organization and the 3D structure of the catalytic centre of a wide range of RdRps, even those with a low overall sequence homology, are conserved. The catalytic center is formed by several motifs containing a number of conserved amino acid residues.
Eukaryotic RNA interference requires a cellular RNA-dependent RNA polymerase (c RdRp). Unlike the "hand" polymerases, they resemble simplified multi-subunit DNA-dependent RNA polymerases (DdRPs), specifically in the catalytic β/β' subunits, in that they use two sets of double-psi β-barrels in the active site. QDE1 () in "Neurospora crassa", which has both barrels in the same chain, is an example of such an enzyme. Bacteriophage homologs, including the similarly single-chain DdRp yonO (), appear to be closer to c RdRps than DdRPs are.
In viruses.
There are 4 superfamilies of viruses that cover all RNA-containing viruses with no DNA stage:
RNA transcription is similar to but not the same as DNA replication.
Flaviviruses produce a polyprotein from the ssRNA genome. The polyprotein is cleaved to a number of products, one of which is NS5, an RNA-dependent RNA polymerase. This RNA-directed RNA polymerase possesses a number of short regions and motifs homologous to other RNA-directed RNA polymerases.
RNA replicase found in positive-strand ssRNA viruses are related to each other, forming three large superfamilies. Birnaviral RNA replicase is unique in that it lacks motif C (GDD) in the palm. Mononegaviral RdRp (PDB 5A22) has been automatically classified as similar to (+)-ssRNA RdRps, specifically one from "Pestivirus" and one from "Leviviridae". Bunyaviral RdRp monomer (PDB 5AMQ) resembles the heterotrimeric complex of Orthomyxoviral (Influenza; PDB 4WSB) RdRp.
Since it is a protein universal to RNA-containing viruses, RdRp is a useful marker for understanding their evolution. The overall structural evolution of viral RdRps has been reviewed.
Recombination.
When replicating its (+)ssRNA genome, the poliovirus RdRp is able to carry out recombination. Recombination appears to occur by a copy choice mechanism in which the RdRp switches (+)ssRNA templates during negative strand synthesis. Recombination frequency is determined in part by the fidelity of RdRp replication. RdRp variants with high replication fidelity show reduced recombination, and low fidelity RdRps exhibit increased recombination. Recombination by RdRp strand switching also occurs frequently during replication in the (+)ssRNA plant carmoviruses and tombusviruses.
Intragenic complementation.
Sendai virus (family "Paramyxoviridae") has a linear, single stranded, negative-sense, nonsegmented RNA genome. The viral RdRp consists of two virus-encoded subunits, a smaller one P and a larger one L. When different inactive RdRp mutants with defects throughout the length of the L subunit where tested in pairwise combinations, restoration of viral RNA synthesis was observed in some combinations. This positive L-L interaction is referred to as intragenic complementation and indicates that the L protein is an oligomer in the viral RNA polymerase complex.
Drug therapies.
RdRps can be used as drug targets for viral pathogens as their function is not necessary for eukaryotic survival. By inhibiting RNA-dependent RNA polymerase function, new RNAs cannot be replicated from an RNA template strand, however, DNA-dependent RNA polymerase will remain functional.
There are currently antiviral drugs against Hepatitis C and COVID-19 that specifically target RdRp. These include Sofosbuvir and Ribavirin against Hepatitis C and Remdesivir, the only FDA approved drug against COVID-19.
GS-441524 triphosphate, is a substrate for RdRp, but not mammalian polymerases. It results in premature chain termination and inhibition of viral replication. GS-441524 triphosphate is the biologically active form of the phosphate pro-drug, Remdesivir. Remdesivir is classified as a nucleotide analog in which it works to inhibit the function of RdRp by covalently binding to and interrupting termination of the nascent RNA through early or delayed termination or preventing further elongation of the RNA polynucleotide. This early termination leads to nonfunctional RNA that will be degraded through normal cellular processes.
RNA interference.
The use of RNA-dependent RNA polymerase plays a major role in RNA interference in eukaryotes, a process used to silence gene expression via small interfering RNAs (siRNAs) binding to mRNA rendering them inactive. Eukaryotic RdRp becomes active in the presence of dsRNA, however, RdRp is only present in a select subset of eukaryotes, including "C. elegans" and "P. tetraurelia". This presence of dsRNA triggers the activation of RdRp and RNAi processes by priming the initiation of RNA transcription through the introduction of siRNAs into the system. In "C. elegans", siRNAs are integrated into the RNA-induced silencing complex, RISC, which works alongside mRNAs targeted for interference to recruit more RdRps to synthesize more secondary siRNAs and repress gene expression.


EMBO Molecular Medicine

EMBO Molecular Medicine is an open-access peer-reviewed medical journal covering research in molecular medicine.
The journal was published by Wiley-Blackwell together with the European Molecular Biology Organization since its launch in 2009, until December 2013, when EMBO Press was started.
According to the "Journal Citation Reports", the journal had a 2017 impact factor of 10.293, ranking it 7th out of 128 journals in the category "Medicine, Research & Experimental".


MannKind Corporation

MannKind Corporation is a biopharmaceutical company focusing on the discovery, development, and commercialization of therapeutic products for diseases such as diabetes and pulmonary arterial hypertension. Based in Westlake Village, California, the company was founded in February 1991.
MannKind Corporation was named after its founder, Alfred E. Mann.
History.
Founded in February 1991, the company's present form is a result of a 2003 merger of three companies owned by Alfred E. Mann: Pharmaceutical Discovery Corporation (PDC), the cancer vaccine developer CTL ImmunoTherapies, Inc., and its sister company Allecure Corp, which was developing an allergy vaccine technology. Pharmaceutical Discovery was purchased in 2001 from Solomon Steiner; with that purchase MannKind acquired the Technosphere molecule and Medtone inhaler, upon which was developed its lead product, Afrezza (inhalable insulin).
The FDA approved Afrezza on June 27, 2014.
On August 11, 2014 MannKind entered into an exclusive global licensing agreement with Sanofi for Afrezza sales. Under the agreement, MannKind received $150 million cash from Sanofi, in exchange for sharing profits and losses of sales of Afrezza, with 65% for Sanofi and 35% for MannKind. On January 5, 2016, MannKind Corporation announced the termination of the license and collaboration agreement with Sanofi. By December 2017, the company had lost 11% of its trading volume due to the poor sales.
In March 2020, the company announced it was working with fellow pharmaceutical company Immix Biopharma to try to develop an inhalable treatment for acute respiratory distress syndrome, a lung disease.
Products and product candidates.
The firm has developed Afrezza a rapid-acting insulin peaking 12 to 15 minutes after inhalation and exiting the body within 2–3 hours. The inhalation technology uses a miniature, breath-powered inhaler in combination with single-use cartridges containing pre-metered doses. Initial pharmacokinetic studies were followed by studies of safety and efficiency involving Technosphere formulations of different therapeutic proteins.
Leadership.
Mann was chief executive officer until January 12, 2015 when Hakan Edstrom became CEO and Mann transitioned to executive chairman.
In November 2015, Hakan Edstrom stepped down as CEO and president. Company founder Alfred Mann stepped in as interim CEO on November 19, 2015. In May 2017, Michael Castagna was named CEO of MannKind Corporation.
Facilities.
MannKind's corporate headquarters are in Westlake Village, California. The Afrezza manufacturing facility is in Danbury, Connecticut.


Biotechnology industry in Boston

Greater Boston, primarily Boston and Cambridge, is home to almost 1,000 biotechnology companies, ranging from small start-ups to billion-dollar pharmaceutical companies. The many universities in the area give the region a large network of scientists.
The Kendall Square area of Boston holds a large concentration of the life science industry, numbering over 120 companies within a mile, and has been described as the "center of the nation’s biotechnology industry". The Longwood area is about two miles from Kendall Square, and is also home to many biomedical research companies.
History.
The biotechnology industry in Boston dates back to the 1970s, when genetic engineering was developing. Biogen was the first company in Boston focused on biotechnology.
In 2008, the governor of Massachusetts announced the Massachusetts Life Sciences Act, promising $1 billion to further the development of the biotech industry. Massachusetts is among the top states for biotech jobs.
In 2016, venture investment in Massachusetts biopharma companies was $2.9 billion, and more than half of the biotech companies in the state receiving venture capital were located in Cambridge. When Cambridge and Boston were considered together, they received more than 80% of the funding in the state. Seven teaching hospitals are located in Boston, contributing to the research efforts. Five of the top six NIH-funded independent hospitals in the United States are located in Boston.


Flesinoxan

Flesinoxan (DU-29,373) is a potent and selective 5-HT1A receptor partial/near-full agonist of the phenylpiperazine class. Originally developed as a potential antihypertensive drug, flesinoxan was later found to possess antidepressant and anxiolytic effects in animal tests. As a result, it was investigated in several small human pilot studies for the treatment of major depressive disorder, and was found to have robust effectiveness and very good tolerability. However, due to "management decisions", the development of flesinoxan was stopped and it was not pursued any further.
In patients, flesinoxan enhances REM sleep latency, decreases body temperature, and increases ACTH, cortisol, prolactin, and growth hormone secretion.


Primary metabolite

A primary metabolite is a kind of metabolite that is directly involved in normal growth, development, and reproduction. It usually performs a physiological function in the organism (i.e. an intrinsic function). A primary metabolite is typically present in many organisms or cells. It is also referred to as a central metabolite, which has an even more restricted meaning (present in any autonomously growing cell or organism). Some common examples of primary metabolites include: lactic acid, and certain amino acids. Note that primary metabolites do not show any pharmacological actions or effects.
Conversely, a secondary metabolite is not directly involved in those processes, but usually has an important ecological function (i.e. a relational function). A secondary metabolite is typically present in a taxonomically restricted set of organisms or cells (plants, fungi, bacteria, etc). Some common examples of secondary metabolites include: ergot alkaloids, antibiotics, naphthalenes, nucleosides, phenazines, quinolines, terpenoids, peptides and growth factors.
Plant growth regulators may be classified as both primary and secondary metabolites due to their role in plant growth and development. Some of them are intermediates between primary and secondary metabolism.


Maynard Olson

Maynard Victor Olson is an American chemist and molecular biologist. As a professor of genome sciences and medicine at the University of Washington, be became a specialist in the genetics of cystic fibrosis, and one of the founders of the Human Genome Project. During his years at Washington University in St. Louis, he also led efforts to develop yeast artificial chromosomes that allowed for the study of large portions of the human genome.
Early life and education.
Olson was born and raised in Bethesda, Maryland where he was educated through their public school system. Upon graduating from high school, he received his undergraduate degree from California Institute of Technology (CalTech) and his doctoral degree in inorganic chemistry from Stanford University in 1970. During his time at Caltech, he attended lectures by Richard Feynman which he said was a "memorable experience."
Career.
Upon graduating with his PhD, Olson worked at Dartmouth College as an inorganic chemist but experienced "an early mid-life crisis" and chose to change fields. He subsequently took a sabbatical and worked with Benjamin Hall at the University of Washington (UW) in Seattle. In 1979, he accepted a position at Washington University in St. Louis (WUSTL), where he began to work on the development of systematic approaches to the analysis of complex genomes. Throughout the 1980s, Olson continued to analyze whole genomes in his own laboratory. He worked with a computer developing algorithms for parallel genome mapping projects through yeast while John Sulston focused on nematode worm, Caenorhabditis elegans. This was one of the very first uses of restriction fragment length polymorphisms to map a cloned gene. In 1989, Olson became a member of the Program Advisory Committee on the Human Genome at the National Institutes of Health (NIH).
At the beginning of the following decade, Olson was the recipient of the 1992 Genetics Society of America Medal for his genetic achievements. During the same year, he returned to UW and joined their Department of Molecular Biotechnology. In 1994, Olson was elected to the United States National Academy of Sciences. At the turn of the century, Olson was a lead scientist on a study mapping the genome of Pseudomonas aeruginosa which was published in "Nature". The implications of this study led to the possibility of new treatments for patients with cystic fibrosis and patients with severe burns and others who develop this type of infection. As a result of his pioneering gene research, he was the co-recipient of Durham, North Carolina's City of Medicine Award. The citation specifically noted that without his discovery, sequencing the human genome "would not have been possible." In 2003, Olson was elected to the American Academy of Arts and Sciences for "developing technological and experimental innovations critical to genome sequencing." He was also the recipient of the 2002 Canada Gairdner International Award and 2007 Gruber Prize in Genetics.


Ryan Julian

Ryan Julian is an American chemist and Professor at the University of California, Riverside. His research uses mass spectrometry to study proteins and protein structure. His work has resulted in over 85 publications and he has been recognized with numerous honors including the American Society for Mass Spectrometry Biemann Medal in 2017.
Julian received his BS in Chemistry from the University of Utah in 1999 and his PhD from the California Institute of Technology in 2003. After postdoctoral work at Indiana University, he was appointed as an Assistant Professor at University of California, Riverside in 2005.


4-MeO-MiPT

4-MeO-MiPT, or 4-methoxy-"N"-methyl-"N"-isopropyltryptamine, is a lesser-known psychedelic drug. It is the 4-methoxy analog of MiPT. 4-MeO-MiPT was first synthesized by Alexander Shulgin and is mentioned in his book "TiHKAL" ("Tryptamines i Have Known And Loved"). Subsequent testing by Shulgin on human test subjects showed the effective dose as 20-30 mg (or 0.4 mg per Kg body weight of subject); the onset time between ingestion and the first noticeable effects was 45-60 min, with sensations lasting between 2-2.5 hours. The sensation were significantly milder than those of 4-HO-MiPT, with 4-MeO-MiPT producing erotic-enhancing effects, and few of the visuals common with tryptamines. Very little data exists about the pharmacological properties, metabolism, and toxicity of 4-MeO-MiPT.


Operation Drop Kick

Between April and November 1956, the U.S. Army Chemical Corps conducted Operation Drop Kick to test the practicality of employing mosquitoes to carry an entomological warfare agent in different ways. The Corps released uninfected female mosquitoes into a cooperative residential area of Savannah, Georgia, and then estimated how many mosquitoes entered houses and bit people. Within a day the mosquitoes had bitten many people. In 1958, the Corps released 600,000 mosquitoes in Avon Park, Florida.
These tests showed that mosquitoes could be spread by means of various devices.
The 1964 movie "Dr. Strangelove" also refers to an Operation Drop Kick.
The TV series "Archer" refers to Operation Drop Kick as the codename of a CIA mission to take over a Latin American country.


Sedimentation equilibrium

Sedimentation equilibrium in a suspension of different particles, such as molecules, exists when the rate of transport of each material in any one direction due to sedimentation equals the rate of transport in the opposite direction due to diffusion. Sedimentation is due to an external force, such as gravity or centrifugal force in a centrifuge.
It was discovered for colloids by Jean Baptiste Perrin for which he received the Nobel Prize in Physics in 1926.
Colloid.
In a colloid, the colloidal particles are said to be in sedimentation equilibrium if the rate of sedimentation is equal to the rate of movement from Brownian motion. For dilute colloids, this is described using the La Place-Perrin distribution law:
formula_1
where
formula_2 is the colloidal particle volume fraction as a function of vertical distance formula_3 above reference point formula_4,
formula_5 is the colloidal particle volume fraction at reference point formula_4,
formula_7 is the buoyant mass of the colloidal particles,
formula_8 is the standard acceleration due to gravity,
formula_9is the Boltzmann constant,
formula_10 is the absolute temperature,
and formula_11 is the sedimentation length.
The buoyant mass is calculated using formula_12
where formula_13 is the difference in mass density between the colloidal particles and the suspension medium, and formula_14 is the colloidal particle volume found using the volume of a sphere (formula_15 is the radius of the colloidal particle).
Sedimentation length.
The La Place-Perrin distribution law can be rearranged to give the sedimentation length formula_11. The sedimentation length describes the probability of finding a colloidal particle at a height formula_3 above the point of reference formula_4. At the length formula_11 above the reference point, the concentration of colloidal particles decreases by a factor of formula_20.
formula_21
If the sedimentation length is much greater than the diameter formula_22 of the colloidal particles (formula_23), the particles can diffuse a distance greater than this diameter, and the substance remains a suspension. However, if the sedimentation length is less than the diameter (formula_24), the particles can only diffuse by a much shorter length. They will sediment under the influence of gravity and settle to the bottom of the container. The substance can no longer be considered a colloidal suspension. It may become a colloidal suspension again if an action to undertaken to suspend the colloidal particles again, such as stirring the colloid.
Example.
The difference in mass density formula_13 between the colloidal particles of mass density formula_26 and the medium of suspension of mass density formula_27, and the diameter of the particles, have an influence on the value of formula_11. As an example, consider a colloidal suspension of polyethylene particles in water, and three different values for the diameter of the particles: 0.1 μm, 1 μm and 10 μm. The volume of a colloidal particles can be calculated using the volume of a sphere formula_29.
formula_26 is the mass density of polyethylene, which is approximately on average 920 kg/m3 and formula_27 is the mass density of water, which is approximately 1000 kg/m3 at room temperature (293K). Therefore formula_32 is -80 kg/m3.
Generally, formula_11 decreases with formula_34. For the 0.1 μm diameter particle, formula_11 is larger than the diameter, and the particles will be able to diffuse. For the 10 μm diameter particle, formula_11 is much smaller than the diameter. As formula_11 is negative the particles will cream, and the substance will no longer be a colloidal suspension.
In this example, the difference is mass density formula_13 is relatively small. Consider a colloid with particles much denser than polyethylene, for example silicon with a mass density of approximately 2330 kg/m3. If these particles are suspended in water, formula_13 will be 1330 kg/m3. formula_11 will decrease as formula_13 increases. For example, if the particles had a diameter of 10 μm the sedimentation length would be 5.92×10−4 μm, one order of magnitude smaller than for polyethylene particles. Also, because the particles are more dense than water, formula_11is positive and the particles will sediment.
Ultracentrifuge.
Modern applications use the analytical ultracentrifuge. The theoretical basis for the measurements is developed from the Mason-Weaver equation. The advantage of using analytical sedimentation equilibrium analysis for Molecular Weight of proteins and their interacting mixtures is the avoidance of need for derivation of a frictional coefficient, otherwise required for interpretation of dynamic sedimentation.
Sedimentation equilibrium can be used to determine molecular mass. It forms the basis for an analytical ultracentrifugation method for measuring molecular masses, such as those of proteins, in solution.


Robert Petre, 7th Baron Petre

Robert Petre, 7th Baron Petre (1689 – 22 March 1713) was a British peer, the son of Thomas Petre, 6th Baron Petre (1633–1706) and his wife Mary Clifton, daughter of Sir Thomas Clifton. He succeeded to his title, at the age of 17, upon the death of his father.
Robert is said to have spurned wearing a wig in the conventional way, spending instead six hours every day dressing his own hair. He caused an uproar of indignation and outrage in the family when, in 1711, being then only 21, in a freak of gallantry cut off a lock of hair from the head of a celebrated beauty, his distant cousin, Arabella Fermor, daughter of Henry Fermor of Tusmore, Oxfordshire.
"The Rape of the Lock".
Alexander Pope, a friend of the family, was prevailed upon to write one of his humorous heroic verses about the incident in the hope that laughter would defuse the situation. The result was "The Rape of the Lock" (first published in "Lintot's Miscellany" in May 1712), which was an enormous public success, selling 3,000 copies in four days. The first version of the poem, however, so lampooned all those involved that it upset the Petres even more and Arabella, flattered to be cast as heroine by the distinguished Mr. Pope, is said to have become "very troublesome and conceited". She became the wife of Francis Perkins of Ufton Court, near Reading, Berkshire in about 1716 and died in 1738.
Personal life.
It is known that Petre lived at Ingatestone Hall, but on the strength of his marriage on 1 March 1712, to Catherine Walmesley (1697 – 31 January 1785), an extremely rich Lancastrian heiress.
Lord Petre intended moving back to Thorndon Hall, the family seat, but died of smallpox, at the age of 23, before doing so. His 16-year-old bride was 6 months pregnant. His son, Robert James Petre, 8th Baron Petre, was born three months after his death.


Aildenafil

Aildenafil (methisosildenafil) is a synthetic chemical compound that is a structural analog of sildenafil (Viagra). It was first reported in 2003, and it is not approved by any health regulation agency. Like sildenafil, aildenafil is a phosphodiesterase type 5 inhibitor.
Aildenafil has been found as an adulterant in a variety of supplements which are sold as "natural" or "herbal" sexual enhancement products. The United States Food and Drug Administration has warned consumers that any sexual enhancement product that claims to work as well as prescription products is likely to contain such a contaminant.


Cob(II)yrinic acid a,c-diamide reductase

In enzymology, a cob(II)yrinic acid a,c-diamide reductase () is an enzyme that catalyzes the chemical reaction
2 cob(I)yrinic acid a,c-diamide + FMN + 3 H+ formula_1 2 cob(II)yrinic acid a,c-diamide + FMNH2
The three substrates of this enzyme are cob(I)yrinic acid a,c-diamide, flavin mononucleotide, and H+; its two products are cob(II)yrinic acid a,c-diamide and FMNH2.
Classification.
This enzyme belongs to the family of oxidoreductases, specifically those oxidizing metal ion with a flavin as acceptor.
Nomenclature.
The systematic name of this enzyme class is cob(I)yrinic acid-a,c-diamide:FMN oxidoreductase. This enzyme is also called CobR and cob(II)yrinic acid-a,c-diamide:FMN oxidoreductase (incorrect).
Biological role.
This enzyme is part of the biosynthetic pathway to cobalamin (vitamin B12) in bacteria.


Sherry Harbin

Sherry Lynn Voytik-Harbin is a professor in the Weldon School of Biomedical Engineering and Department of Basic Medical Sciences at Purdue University.
Early life and education.
Harbin was born and raised in Indiana. As a senior at Central High School, she won the State Scholarly Writing Contest and was the recipient of a Storer Scholarship for Indiana University. Upon graduating in 1987, Harbin was expected to enroll at Harvard University and the Dana–Farber Cancer Institute for graduate work in experimental pathology but instead chose to explore Purdue University. She made contact with Pete Konrad and they discussed opportunities in biomedical engineering which convinced her to enroll at the institution. As a doctoral student, she was the recipient of a $500 Geddes-Laufman-Greatbatch Scholarship due to her academic performance.
Career.
Harbin joined the faculty of Weldon School of Biomedical Engineering in 2003 as a full-time professor of biomedical engineering and basic medical sciences. In this role, she studied tissue engineering on the Extra-Cellular Matrix to understand the behavior of the reactions. She was later promoted to Associate Professor with tenure in 2006. Harbin was later selected for the 2008 Entrepreneurial Leadership Academy. Harbin continued to research the use of decellularized tissue scaffolds for tissue restoration in human patients and was nominated to the Purdue Innovator Hall of Fame in 2014. Her research laboratory developed collagen formulations that self-assemble to form fibrils that resemble those found in the body's tissues, which could then be used in creating tissue-engineered medical products as well as in-vitro 3D tissue systems for basic research, drug development, and chemical toxicity testing. She was subsequently elected a Fellow of the National Academy of Inventors and named a University Faculty Scholar as an "outstanding faculty member who are on an accelerated path for academic distinction in the discovery and dissemination of knowledge."
During the COVID-19 pandemic, Harbin was elected a Fellow of the American Institute for Medical and Biological Engineering for "developing collagen formulations that rapidly self-assemble at physiological conditions into a mechanically and proteolytic stable material that promotes tissue regeneration." The following year, she collaborated with Stacey Halum to lead a research team in develop tissue-engineered component tissue replacements that support the reconstruction of the larynx.
Personal life.
Harbin married Scot A. Harbin in 1994 in Indiana.


Robert E. Finnigan

Robert Emmet Finnigan (born May 27, 1927) is an American pioneer in the development of gas chromatography–mass spectrometry equipment (GC/MS). Finnigan founded the Scientific Instruments Division of Electronic Associates, Inc., producing the first commercial quadrupole mass spectrometer in 1964. He then formed Finnigan Instruments Corporation to combine a computer system with a quadrupole mass spectrometer and gas chromatograph. Finnigan's GC/MS/computer systems are used to detect and identify trace organic compounds, making them important instruments for the monitoring and protection of the environment. They were adopted by the United States Environmental Protection Agency as a standard instrument for monitoring water quality and were fundamental to the work of the EPA.
Early life and education.
Robert Finnigan was born on May 27, 1927, in Buffalo, New York to Charles M. and Marie F. Finnigan. He was one of seven children, who were raised primarily by their father after their mother's early death.
Robert Finnigan entered the United States Naval Academy in Annapolis, Maryland in June 1945, graduating in 1949 with a Bachelor of Science. On April 1, 1950, he married Bette Earl Van Horn at Perrin Air Force Base in Sherman, Texas. The couple had met while he was at Tyndall Air Force Base near Panama City, Florida.
Because of his strong interest and aptitude in electrical engineering, he was able to enroll in an Air Force Institute of Technology program that sent qualified officers to graduate school.
In 1952, he entered the University of Illinois at Urbana–Champaign, receiving an M.S. in electrical engineering in 1954 and a Ph.D. in electrical engineering in 1957.
His master's thesis work with Edward C. Jordan used the ILLIAC to solve complex mathematical functions in antenna theory. For his Ph.D. he researched servomechanism theory with Gilbert Fett, completing the thesis "Transient Analysis of Non-Linear Servomechanisms Using Describing Functions with Root-Locus Techniques".
Lawrence Livermore Laboratory.
In 1957, as a Captain in the United States Air Force, Robert Finnigan joined the University of California Radiation Laboratory at Livermore (later the Lawrence Livermore National Laboratory). Finnigan worked on Project Pluto, a United States government program to develop nuclear powered ramjet engines for the Supersonic Low Altitude Missile (SLAM), a type of cruise missile. Finnigan led the group that developed computer control systems for the nuclear reactor that powered the missile.
In 1959, Finnigan had the choice of rotating to a different tour of duty in the Air Force, or resigning from the Air Force and staying at Livermore. He remained at Livermore for two more years. Finnigan's group developed the Tory II-A prototype and Tory II-C reactor and controls, which were tested at the Nevada Test Site in the 1960s.
Stanford Research Institute.
In 1962, Finnigan and one of his coworkers, physicist and nuclear engineer P. Michael Uthe, Jr., left Livermore to work for the Stanford Research Institute (SRI) in Palo Alto, California. Finnigan was hired to establish a process controls group in SRI's control systems lab. SRI did contract research projects for both business and the military. One of the projects underway at SRI, led by Kenneth R. Shoulders, was developing a quadrupole mass spectrometer. Finnigan saw the potential for using the quadrupole broadly as a detector for instrumentation and process-control, and began trying to find support for its development and commercialization.
Electronic Associates, Inc..
In 1963, Finnigan and Uthe joined Electronic Associates, Inc. (EAI). The main research department of the company was based in Princeton, New Jersey, but Finnigan founded a new Scientific Instruments Division in Palo Alto, California. Finnigan's vision involved creation of a broad-based line of process-controlled instruments, beginning with the quadrupole mass spectrometer. Based on previous research at SRI, Finnigan was convinced that a market existed, but EAI and other companies such as IBM and Beckman Instruments were not interested in developing the quadrupole as a product at that time. Finnigan's group proposed to contract parts of the quadrupole production to SRI, but management at SRI were not interested in its commercial development either. Eventually Finnigan collaborated with staff from SRI, who supplied knowledge and expertise to help Finnigan's group bootstrap development of a prototype quadrupole analyzer at EAI. Because of the strong market demand the EAI division was able to sell more than 500 of these quadrupole residual gas analyzers between 1964 and 1966.
Finnigan wanted to pursue development of computer-controlled instrumentation for a combined gas chromatograph (GC) and quadrupole mass spectrometer (MS). Hpwever, EAI's main focus was analog computers, and they were not interested in developing a computerized GC/MS. On December 31, 1966, after EAI unsuccessfully attempted to sell the division to Syntex Corporation, Finnigan submitted his resignation to EAI.
Finnigan Instrument Corporation.
In 1967, Finnigan formed Finnigan Instrument Corporation with venture capital from Roger Sant and T. Z. Chu. He was joined by Michael Story from EAI, and William Fies from SRI.
In early 1968, Finnigan Instrument Corporation delivered its first prototype quadrupole GC/MS instruments. One was sent to Nobel prizewinner Joshua Lederberg at Stanford University. The other was sent to Purdue University.
The first commercial model for a computerized GC/MS, Finnigan's Model 1015/System 150, was introduced soon after for a price of $100,000. The first delivery went to Evan Charles Horning and Marjorie G. Horning at Baylor Medical College. For three years, Finnigan was the only company producing a computerized GC/MS. The next one to be introduced came from the Hewlett-Packard Company in 1971.
Quadrupole mass spectrometry offered advantages in terms of size, cost, speed and sensitivity compared to the magnetic-sector mass spectrometry equipment most commonly used at that time. Quadrupoles offered high sensitivity and high pressure tolerance. They could operate with a low voltage ion source. Rapid scanning became feasible because computers could be used to step the spectrometer from one ion peak to the next. This allowed acquisition and display of data in real-time, and gave operators the potential to interact with the system and modify what was being monitored. A major strength of the instrument was precise quantitation. It could be used to detect trace contaminants in environmental samples, to identify drugs in a case of overdose, and to measure drug metabolites.
After the United States Environmental Protection Agency (EPA) was established in 1970, it became a major customer for Finnigan's GC/MS. The EPA surveyed possible monitoring instruments for use in monitoring organic pollutants. Speed, cost, and performance were all important concerns. The target machine was projected as having the ability to scan for pesticides with a resolving power of 1,000 to 10,000, across a broad range of 10 nanograms to one microgram. A computer-controlled system was desirable. An international array of instruments were reviewed, of which only two used quadrupole technology. An expert panel recommended Finnigan's quadrupole GC/MS to the EPA for further evaluation, and twenty Finnigan Model 1015/System 150 instruments were ordered soon after by the EPA. Finnigan published a 1979 study, based on users, indicating that in spite of the high initial cost of the equipment, the Finnigan GC/MS was reliable and cost-effective. By 1979, the Finnigan GC/MS was the preferred instrument at the EPA for the analysis of environmental pollutants in water and wastewater. The models most generally used were Finnigan Corporation's 1015 and 3000 series of quadrupole mass spectrometers with a data system based on DEC's PDP-8 computers. The EPA also based its instruction manuals and standards for environmental testing on the Finnigan GC/MS, publishing the results in the "Federal Register" in 1979. By 1984, all public water was to be tested by using a GC/MS apparatus. In the 1980s, an estimated 60-70% of Finnigan's GC/MS sales went to the environmental market.
GC/MS technology, of which Finnigan Instrument Corporation's instrument was the first, was the technical underpinning that made it possible for the EPA to carry out its regulatory efforts in the 1970s. About 100 organic compounds could be identified in water prior to 1970. By 1975, nearly 1500 organic pollutants had been identified. Without the ability to detect such compounds, their monitoring and regulation would not have been possible.
When Finnigan Instrument Corporation was acquired by Thermo Instrument Systems (later Thermo Fisher Scientific) in 1990, the firm was considered "the world's leading manufacturer of mass spectrometers". Robert Finnigan continued to consult for the company for several years after the acquisition. He has also consulted with other entrepreneurial companies.
Other activities.
Robert Finnigan served on the board of directors of the trade organization American Electronics Association (AEA). He and Dean O. Morton were founders of the AEA's Environmental and Occupational Health activities. Finnigan also co-founded the Organization Internationale Metrology Legale (OIML) for legal metrology. With the support of the National Bureau of Standards (NBS) they developed protocols for international regulations in fifty-one nations. In many cases, these closely matched the standards of the EPA.


Membrane channel

Membrane channels are a family of biological membrane proteins which allow the passive movement of ions (ion channels), water (aquaporins) or other solutes to passively pass through the membrane down their electrochemical gradient. They are studied using a range of channelomics experimental and mathematical techniques. Insights have suggested endocannabinoids (eCBs) as molecules that can regulate the opening of these channels during diverse conditions.
Properties.
Hemichannels.
A hemichannel is a membrane channel made up of six subunits. A hemichannel is defined as one-half of a gap junction channel. Hemichannels consist of connexins.
Pannexin.
Pannexins are involved in the process of purinergic signalling. They release adenosine triphosphate (ATP), which activate purinergic receptors. On the other hand, purinergic receptor activation can also lead to the opening of the channel, via a positive feedback loop. In addition, P2Y receptors activate inositol trisphosphate, which leads to a transient increase in intracellular calcium, and opens both connexin and pannexin channels, therefore contributing to the propagation of calcium waves across astrocytes and epithelial cells.


Megakaryoblast

A megakaryoblast is a precursor cell to a promegakaryocyte, which in turn becomes a megakaryocyte during haematopoiesis. It is the beginning of the thrombocytic series.
Development.
The megakaryoblast derives from a CFU-Meg colony unit of pluripotential hemopoietic stem cells. (Some sources use the term "CFU-Meg" to identify the CFU.) The CFU-Meg derives from the CFU-GEMM (common myeloid progenitor).
Structure.
These cells tend to range from 8μm to 30μm, owing to the variation in size between different megakaryoblasts. The nucleus is three to five times the size of the cytoplasm, and is generally round or oval in shape. Several nucleoli are visible, while the chromatin varies from cell to cell, ranging from fine to heavy and dense. The cytoplasm is generally basophilic and stains blue. In smaller cells, it contains no granules, but larger megakaryoblasts may contain fine granules.


N-Methylspiperone

"N"-Methylspiperone (NMSP) is a derivate of spiperone that is used to study the dopamine and serotonin neurotransmitter systems. Labeled with the radioisotope carbon-11, it can be used for positron emission tomography.


Reducing equivalent

In biochemistry, the term reducing equivalent refers to any of a number of chemical species which transfer the equivalent of one electron in redox reactions. A redox reaction (oxidation-reduction reaction) results in a change of oxidation state of atoms or ions due to actual or formal transfer of electrons. A chemical species is reduced when it gains electrons and is oxidized when it loses electrons. A reducing equivalent serves as the electron donor in a redox reaction and becomes oxidized (loses electrons) when it donates an electron to an electron acceptor. A reducing equivalent can donate an electron in multiple ways: as a lone electron, as a hydrogen atom, as a hydride ion, or by bond formation with an oxygen atom.
Lone electrons.
In redox reactions involving metal ions, lone electrons can be transferred from the electron donor to the electron acceptor. That is, no other atoms or protons are transferred along with the electron in the redox reaction. For instance, consider the following reaction between iron and copper ions:
The iron and copper ion each begin the reaction with a double positive charge (2+). At the end of the reaction, the charge on copper decreased to a single positive charge (1+) while the charge on iron increased to a triple positive charge (3+). The alteration of charges is due to the transfer of a single electron from the iron atom to the copper atom. In this reaction, iron is acting as the reducing equivalent because it donates one of its electrons to copper. As a result, iron is oxidized because it loses one of its electrons resulting in a greater positive charge.
Hydrogen atom.
A neutral hydrogen atom consists of one electron and one proton. Hydrogen's electronegativity value of 2.2 is less than the electronegativity of the atoms that hydrogen is commonly bound to, such as oxygen, nitrogen, carbon, or fluorine. When a hydrogen atom forms a covalent bond with a more electronegative atom, the more electronegative atom will have a greater affinity for the electron and pull the electron partially away from hydrogen. The more electronegative atom is reduced because it formally gains the electrons involved in the covalent bond. Conversely, when an atom loses a bond to a hydrogen atom it is oxidized because it loses electrons. For example, consider the reaction involving Flavin Adenine Dinucleotide (FAD) and succinate. In this reaction FAD is reduced to FADH2 because it accepts two hydrogen atoms from succinate. Succinate serves as the reducing equivalent because it donates electrons to FAD in the form of hydrogen atoms and is itself oxidized.
Hydride.
A hydride ion is a hydrogen anion consisting of one proton and two electrons. A chemical species that donates a hydride is a reducing equivalent because it donates the equivalence of at least one electron, regardless if it is in the form of a hydride. The chemical species that accepts a hydride ion will be reduced because it gains the electrons from the hydride ion. The reduced form of Nicotinamide Adenine Dinucleotide (NADH) is a reducing equivalent commonly seen in biochemistry that donates a hydride ion to an electron acceptor in complex I of the mitochondrial electron transport chain.
Bond formation with oxygen atom.
A chemical species with a lower electronegativity than oxygen can serve as a reducing equivalent when it covalently binds to an oxygen atom. Oxygen is highly electronegative and will have a greater affinity for electrons in a covalent bond, resulting in the reduction of the oxygen atom. When an atom of lower electronegativity forms a bond with oxygen it is oxidized because the electrons are pulled closer to oxygen and away from that atom. For instance, consider the formation of a carboxylic acid from the oxidation of an aldehyde. In this reaction, a carbon has been oxidized through the formation of a covalent bond with oxygen.
Reducing equivalents in the mitochondrial respiratory chain.
Oxidative phosphorylation is the process driving ATP synthesis by means of the energy of O2 released through the oxidation of reducing equivalents. It occurs in the mitochondrial electron transport chain, which is located at the inner mitochondrial membrane and consists of transmembrane protein complexes that catalyze redox reactions. NADH and FADH2 are reducing equivalents that donate electrons at complexes I and II, respectively. These electrons are then transferred in multiple redox reactions and are carried to the complexes III and IV. The oxidation of reducing equivalents in the electron transport chain releases protons into the intermembrane space of the mitochondria and maintains the proton electrochemical gradient. As protons move down the electrochemical gradient through the transmembrane protein ATP synthase, ATP is generated from ADP and an inorganic phosphate group. In order to maintain the proton gradient and generate ATP, reducing equivalents are supplied to the electron transport chain from multiple processes such as the TCA cycle.


Amine oxidase

An amine oxidase is an enzyme that catalyzes the oxidative cleavage of alkylamines into aldehydes and ammonia:
Amine oxidases are divided into two subfamilies based on the cofactor they contain: