The short version of epithalamin fits in a sentence. The long version — which is the one that helps — is below.
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Laboratory work has examined effects on telomerase activity in cultured cells, on melatonin rhythms in animals, and on markers of oxidative stress. Some experiments report measurable changes while others show none, and the reported findings rest largely on small studies. The absence of large independent trials means the generality of these results is unresolved rather than settled. Review articles occasionally apply the label geroprotector, a term that reflects a research hypothesis about ageing rather than an established clinical finding.
Epitalon is the common name for a synthetic tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, usually abbreviated AEDG. All four residues are proteinogenic amino acids, and the free peptide has a calculated mass near 390 grams per mole. Because the chain is short and carries no modifications, it is assembled readily by solid-phase synthesis and is distributed mainly as a freeze-dried solid for laboratory work. Catalogue listings use the spellings epitalon, epithalone, and simply AEDG, and the three refer to the same sequence.
The compound is generally presented as a synthetic fragment of epithalamin, a pineal gland extract investigated in the former Soviet Union from the 1970s onward. Vladimir Khavinson and colleagues in Saint Petersburg developed short peptides modelled on such extracts, and epitalon became the most widely cited of those sequences. Most primary reports appeared in Russian-language journals or in proceedings with limited international circulation. Independent replication in laboratories outside that network remains sparse, and much repeated secondary material traces back to a small number of originating groups.
Laboratory-grade epitalon is typically supplied as a lyophilized powder. Purity is commonly assessed with reverse-phase high-performance liquid chromatography, often paired with mass spectrometry to confirm molecular identity. Amino acid analysis and peptide mapping can provide additional confirmation of sequence. Certificates of analysis for research materials frequently report purity above 95 percent, although the methods behind such figures vary between suppliers. The absence of a pharmacopeial monograph means that no single standardized assay defines the compound, so reported results depend on the analytical protocol chosen.
Storage recommendations center on limiting moisture, heat, and light. The dry powder is generally kept at minus 20 degrees Celsius, and some suppliers recommend minus 80 degrees for long-term archival. Once dissolved, solutions are usually aliquoted and frozen to avoid repeated freeze-thaw cycles, which can promote aggregation or degradation. Aqueous stability depends on pH and concentration, and buffered saline is often preferred over plain water for biological work. Stability data specific to epitalon remain limited, so general peptide-handling practices are applied by analogy rather than from product-specific validation.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C14H22N4O9 | Computed for the free acid of Ala-Glu-Asp-Gly |
| Molecular mass | About 390.35 g/mol | Free peptide; salt forms shift the value |
| Appearance | White to off-white solid | Typical of short peptides after freeze-drying |
| Solubility class | Freely soluble in water | Aqueous buffers are also commonly used |
| Common synonyms | Epitalon, epithalone, AEDG | AEDG is the single-letter sequence |
In its supplied form epitalon is a white to off-white powder, usually lyophilized and often hygroscopic. It dissolves readily in water and in aqueous buffers, and it is commonly handled as the acetate or trifluoroacetate salt to improve stability during purification and drying. The amide backbone is labile in aqueous media, so solutions are less durable than the dry solid. Handling notes in the chemical literature therefore emphasize keeping the powder dry, cool and shielded from light until it is dissolved.
Epitalon is a synthetic tetrapeptide whose sequence is alanine-glutamate-aspartate-glycine, written in single-letter code as AEDG. The four residues are joined by three peptide bonds, giving a linear backbone with no branching and no disulfide bridges. Its calculated molecular mass for the free form is approximately 390.3 daltons, a figure that rises when the compound is supplied as an acetate or trifluoroacetate salt. Because the chain is short, the molecule is defined entirely by its residue order rather than by any folded three-dimensional structure.
The parent extract epithalamin was characterised as a low-molecular-weight fraction of pineal tissue rather than a single defined chemical entity. Researchers fractionated it and tested successive fragments for activity, a screening approach typical of peptide discovery work in that era. Epitalon emerged from that process as one of the shorter sequences of interest. Because the original extract was never fully resolved into individual components, claims about which constituent drives a given effect rest on inference. This distinction matters when reading older reports that attribute extract observations to the tetrapeptide itself.
Epitalon is a synthetic tetrapeptide with the residue sequence alanine-glutamate-aspartate-glycine, commonly abbreviated AEDG. Its monoisotopic mass is approximately 390.35 daltons, and it is usually supplied as a lyophilised trifluoroacetate or acetate salt. The compound was derived from a pineal gland extract called epithalamin, a heterogeneous preparation investigated in the former Soviet Union. Researchers associated with the Saint Petersburg Institute of Bioregulation and Gerontology described the tetrapeptide as a constituent fragment of that extract. Commercial material is offered as a laboratory reagent rather than as a finished pharmaceutical product.
Virtually all infections with rabies resulted in death until two French scientists, Louis Pasteur and Émile Roux, developed the first rabies vaccination in 1885. Nine-year-old Joseph Meister (1876–1940), who had been mauled by a rabid dog, was the first human to receive this vaccine. The treatment started with a subcutaneous injection on 6 July 1885, at 8:00 pm, which was followed with 12 additional doses administered over the following 10 days. The first injection was derived from the spinal cord of an inoculated rabbit which had died of rabies 15 days earlier. All the doses were obtained by attenuation, but later ones were progressively more virulent. After the rabies vaccine created by Louis Pasteur was first introduced in France in 1885, its use soon spread to other countries, including outside of Europe. The vaccine was first used in the United States in 1886. In 1888, France established the Pasteur Institute. During the following decades, several similar specialized rabies prevention centers ("Pasteur Institutes") appeared around the world. By 1909 there were 75 such rabies centers worldwide, including in French Indochina. Victims of animal bites in Siam were already receiving the rabies vaccine as early as 1891, becoming the first patients to receive it in Asia. By the late 19th century, European jurisdictions were regulating rabies treatment by opening their own rabies centers or by directing patients to the nearest centers abroad.
== Definition == The chirality of a molecule is based on the molecular symmetry of its conformations. A conformation of a molecule is chiral if and only if it belongs to the Cn, Dn, T, O, or I point groups (the chiral point groups). However, whether the molecule itself is considered to be chiral depends on whether its chiral conformations are persistent isomers that could be isolated as separated enantiomers, at least in principle, or the enantiomeric conformers rapidly interconvert at a given temperature and timescale through low-energy conformational changes (rendering the molecule achiral). For example, despite having chiral gauche conformers that belong to the C2 point group, butane is considered achiral at room temperature because rotation about the central C–C bond rapidly interconverts the enantiomers (3.4 kcal/mol barrier). Similarly, cis-1,2-dichlorocyclohexane consists of chair conformers that are nonidentical mirror images, but the two can interconvert via the cyclohexane chair flip (~10 kcal/mol barrier). As another example, amines with three distinct substituents (R1R2R3N:) are also regarded as achiral molecules because their enantiomeric pyramidal conformers rapidly undergo pyramidal inversion. However, if the temperature in question is low enough, the process that interconverts the enantiomeric chiral conformations becomes slow compared to a given timescale. The molecule would then be considered to be chiral at that temperature.
== Definitions == Corrective rape is the use of rape against people who do not conform to perceived social norms regarding human sexuality or gender roles. The goal is to punish perceived abnormal behavior and reinforce societal norms. The crime was first identified in South Africa, where it is sometimes supervised by members of the woman's family or local community. One of the earliest known mentions of the term is by South African feminist activist Bernedette Muthien during an August 2001 interview by Human Rights Watch in Cape Town:
position effect Any effect on the expression or functionality of a gene or sequence that is a consequence of its location or position within a chromosome or other DNA molecule. A sequence's precise location relative to other sequences and structures tends to strongly influence its activity and other properties, because different loci on the same molecule can have substantially different genetic backgrounds and physical/chemical environments, which may also change over time. For example, the transcription of a gene located very close to a nucleosome, centromere, or telomere is often repressed or entirely prevented because the proteins that make up these structures block access to the DNA by transcription factors, while the same gene is transcribed at a much higher rate when located in euchromatin. Proximity to promoters, enhancers, and other regulatory elements, as well as to regions of frequent transposition by mobile elements, can also directly affect expression; being located near the end of a chromosomal arm or to common crossover points may affect when replication occurs and the likelihood of recombination. Position effects are a major focus of research in the field of epigenetics.
Sources: en.wikipedia.org
From May 1991 to the end of the year, the EPRDF is suspected to have committed dozens of summary executions despite the government's lack of information surrounding state-sanctioned executions. The 1992 elections for 14 new regional assemblies were widely criticized by international observers who asserted that instances of fraud and the arrests of opposition leaders rendered the elections' results, which overwhelmingly favored the EPRDF, meaningless. For instance, in many cases, candidates representing the All-Amhara People's Organization were prevented from registering themselves in various constituencies. Similarly, candidates representing the Oromo Liberation Front (OLF) were threatened, harassed, and detained by the EPRDF. Despite a law that lifted nearly all of the censorship restrictions enacted by the PDRE, much of the media was still controlled by the government and many journalists were still reluctant to risk challenging the TGE or raising awareness of the regime's abuses. Later, the TGE created a Special Prosecutor's Office to begin investigating government personnel associated with the previous regime or Mengistu's Worker's Party of Ethiopia, deciding to formally suspend habeas corpus from August 1992 to the end of the year. By the end of the year, however, none of the detainees had been charged with any crimes.
It is recommended that a water concentration of 2 μg Se/L be considered highly hazardous to sensitive fish and aquatic birds. Selenium poisoning can be passed from parents to offspring through the egg, and selenium poisoning may persist for many generations. Reproduction of mallard ducks is impaired at dietary concentrations of 7 μg Se/L. Many benthic invertebrates can tolerate selenium concentrations up to 300 μg/L of selenium in their diet. Bioaccumulation of selenium in aquatic environments causes fish kills depending on the species in the affected area. There are, however, a few species that have been seen to survive these events and tolerate the increased selenium. It has also been suggested that the season could have an impact on the harmful effects of selenium on fish. Substantial physiological changes may occur in fish with high tissue concentrations of selenium. Fish affected by selenium may experience swelling of the gill lamellae, which impedes oxygen diffusion across the gills and blood flow within the gills. Respiratory capacity is further reduced due to selenium binding to hemoglobin. Other problems include degeneration of liver tissue, swelling around the heart, damaged egg follicles in ovaries, cataracts, and accumulation of fluid in the body cavity and head. Selenium often causes a malformed fish fetus which may have problems feeding or respiring; distortion of the fins or spine is also common. Adult fish may appear healthy despite their inability to produce viable offspring.
The actions of Δ9-THC result from its partial agonist activity at the cannabinoid receptor CB1 (Ki = 40.7 nM), located mainly in the central nervous system, and the CB2 receptor (Ki = 36 nM), mainly expressed in cells of the immune system. The psychoactive effects of THC are primarily mediated by the activation of (mostly G-coupled) cannabinoid receptors, which result in a decrease in the concentration of the second messenger molecule cAMP through inhibition of adenylate cyclase. The presence of these specialized cannabinoid receptors in the brain led researchers to the discovery of endocannabinoids, such as anandamide and 2-arachidonoyl glyceride (2-AG). THC is a lipophilic molecule and may bind non-specifically to a variety of entities in the brain and body, such as adipose tissue (fat). THC, as well as other cannabinoids that contain a phenol group, possess mild antioxidant activity sufficient to protect neurons against oxidative stress, such as that produced by glutamate-induced excitotoxicity. THC targets receptors in a manner far less selective than endocannabinoid molecules released during retrograde signaling, as the drug has a relatively low cannabinoid receptor affinity. THC is also limited in its efficacy compared to other cannabinoids due to its partial agonistic activity, as THC appears to result in greater downregulation of cannabinoid receptors than endocannabinoids. Furthermore, in populations of low cannabinoid receptor density, THC may even act to antagonize endogenous agonists that possess greater receptor efficacy.
Most of these parameters cannot be determined quantitatively, at least during the early phases of a project. The best way to take advantage of a project portfolio is to develop and use it in an iterative way. By comparing the entries at regular intervals, for instance, every 3 months, the directions that the projects take can be visualized. If a negative trend persists with one particular project, the project should be put on the watch list.
Hamazaki H, Hotta K (1979). "Purification and characterization of an α-glucosidase specific for hydroxylysine-linked disaccharide of collagen". J. Biol. Chem. 254 (19): 9682–7. doi:10.1016/S0021-9258(19)83570-6. PMID 385589. Hamazaki H, Hotta K (1980). "Enzymatic hydrolysis of disaccharide unit of collagen. Isolation of 2-O-α-D-glucopyranosyl-O-β-D-galactopyranosyl-hydroxylysine glucohydrolase from rat spleens". Eur. J. Biochem. 111 (2): 587–91. doi:10.1111/j.1432-1033.1980.tb04975.x. PMID 7460918. Sternberg M, Spiro RG (1979). "Studies on the catabolism of the hydroxylysine-linked disaccharide units of basement membranes and collagens. Isolation and characterization of a rat kidney α-glucosidase of high specificity". J. Biol. Chem. 254 (20): 10329–36. doi:10.1016/S0021-9258(19)86713-3. PMID 385599.
Sources: en.wikipedia.org
Despite its feathers, palaeontologists do not consider Sinosauropteryx to be a bird. Phylogenetically, the genus is only distantly related to the clade Aves, usually defined as Archaeopteryx lithographica plus modern birds. The scientists who described Sinosauropteryx, however, used a character-based, or apomorphic, definition of the Class Aves, in which any animal with feathers is considered to be a bird. They argued that the filamentous plumes of Sinosauropteryx represent true feathers with a rachis and barbs, and thus that Sinosauropteryx should be considered a true bird. They classified the genus as belonging to a new biological order, Sinosauropterygiformes, family Sinosauropterygidae, within the subclass Sauriurae. These proposals have not been accepted, and Sinosauropteryx is generally classified in the family Compsognathidae, a group of small-bodied long-tailed coelurosaurian theropods known from the Late Jurassic and Early Cretaceous of Asia, Europe, and South America. Below is a cladogram showing the placement of Sinosauropteryx within Coelurosauria by Senter et al. in 2012.
Systemic scleroderma, or systemic sclerosis, is an autoimmune rheumatic disease characterised by excessive production and accumulation of collagen, called fibrosis, in the skin and internal organs and by injuries to small arteries. There are two major subgroups of systemic sclerosis based on the extent of skin involvement: limited and diffuse. The limited form affects areas below, but not above, the elbows and knees with or without involvement of the face. The diffuse form also affects the skin above the elbows and knees and can also spread to the torso. Visceral organs, including the kidneys, heart, lungs, and gastrointestinal tract can also be affected by the fibrotic process. Prognosis is determined by the form of the disease and the extent of visceral involvement. Patients with limited systemic sclerosis have a better prognosis than those with the diffuse form. Death is most often caused by lung, heart, and kidney involvement. The risk of cancer is increased slightly. Survival rates have greatly increased with effective treatment for kidney failure. Therapies include immunosuppressive drugs, and in some cases, glucocorticoids.
== Research == In both autoimmune and inflammatory diseases, the condition arises through aberrant reactions of the human adaptive or innate immune systems. In autoimmunity, the patient's immune system is activated against the body's own proteins. In chronic inflammatory diseases, neutrophils and other leukocytes are constitutively recruited by cytokines and chemokines, resulting in tissue damage. Mitigation of inflammation by activation of anti-inflammatory genes and the suppression of inflammatory genes in immune cells is a promising therapeutic approach. There is a body of evidence that once the production of autoantibodies has been initialized, autoantibodies have the capacity to maintain their own production.
Potassium (19K) has 25 known isotopes from 34K to 57K as well as 31K, as well as an unconfirmed report of 59K. Three of those isotopes occur naturally: the two stable forms 39K (93.26%) and 41K (6.72%), and the long-lived radioisotope 40K (0.012%). Naturally occurring radioactive 40K decays with a half-life of 1.248×109 years. 89% of those decays are to stable 40Ca by beta decay, whilst 11% are to 40Ar by either electron capture or positron emission. This latter decay branch has produced an isotopic abundance of argon on Earth which differs greatly from that seen in gas giants and stellar spectra. 40K has the longest known half-life for any positron-emitting nuclide. The long half-life of this primordial radioisotope is caused by a highly spin-forbidden transition: 40K has a nuclear spin of 4, while both of its decay daughters are even–even isotopes with spins of 0. 40K occurs in natural potassium in sufficient quantity that large bags of potassium chloride commercial salt substitutes can be used as a radioactive source for classroom demonstrations. 40K is the largest source of natural radioactivity in healthy animals and humans, greater even than 14C. In a human body of 70 kg mass, about 4,300 nuclei of 40K decay per second. The decay of 40K to 40Ar is used in potassium-argon dating of rocks. Minerals are dated by measurement of the concentration of potassium and the amount of radiogenic 40Ar that has accumulated. 40K has also been extensively used as a radioactive tracer in studies of weathering.
Sources: en.wikipedia.org
It is a four-amino-acid peptide with the sequence alanine-glutamate-aspartate-glycine. The chain is unmodified and contains only standard proteinogenic residues, which makes it straightforward to produce by solid-phase synthesis and to characterise by standard peptide methods.
Epitalon and epithalon both circulate, and the difference reflects transliteration of a name coined in Russian-language publications. Reference to the extract it derives from, epithalamin, explains the shared stem. Databases and suppliers are inconsistent, so a search for one spelling alone may miss relevant entries.
No. Epithalamin is a multi-component preparation obtained from pineal tissue, and its exact composition is not fully characterised. Epitalon is a single defined tetrapeptide described as a short synthetic counterpart of that extract, so the two are related in origin but not interchangeable in identity.
Epitalon is a synthetic tetrapeptide built from four amino acids: alanine, glutamate, aspartate, and glycine. It is not extracted from a natural source but made in the laboratory by chemical synthesis. Its short length makes it relatively straightforward to produce at high purity.