Everything below concerns epithalamin. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-08-01. Where a claim depends on a specific study, the study is described rather than over-claimed.
Epitalon is a synthetic tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, commonly abbreviated AEDG. It was designed at the St. Petersburg Institute of Bioregulation and Gerontology as a short, chemically defined analogue of epithalamin, a fraction obtained from bovine pineal tissue. Small peptide bioregulators of this type formed a long-running line of work there from the 1980s onward. Because the molecule is produced by solid-phase synthesis rather than extraction, its composition is exact and its purity can be measured directly.
The most frequently cited proposed action is induction of telomerase, the enzyme that adds repeat sequences to chromosome ends. Cell-culture work from the originating group reported higher telomerase reverse transcriptase expression and measurable telomere elongation in human somatic cells after exposure. How a four-residue peptide would reach nuclear gene regulation is not established, and no cell-surface receptor or uptake route has been identified. Additional reports describe changes in melatonin secretion, antioxidant enzyme activity and lipid peroxidation in aged animals, but these findings remain mechanistically unconnected to the telomerase observation.
Epitalon is a synthetic tetrapeptide with the amino acid sequence alanine-glutamate-aspartate-glycine, abbreviated Ala-Glu-Asp-Gly or AEDG. It was developed by the Russian researcher Vladimir Khavinson and colleagues during work on peptide bioregulators derived from the pineal gland. The compound is short enough to be produced by standard solid-phase peptide synthesis and is typically handled as a lyophilized white powder. Its small size distinguishes it from larger pineal peptides such as epithalamin, a complex extract from which the tetrapeptide was conceptually derived.
The four residues give epitalon a molecular formula of C14H22N4O9 and a molecular weight near 390.35 daltons. The presence of two acidic residues, glutamate and aspartate, makes the free peptide strongly acidic, while the alanine and glycine ends provide neutral, nonpolar character. This combination produces a molecule with substantial water solubility. Because there are no cysteine, methionine, or tryptophan residues, the peptide lacks the most common oxidation-sensitive side chains, which simplifies handling compared with many longer peptides.
The proposed relationship between epitalon and pineal function is a central part of its background. Khavinson's group reported that short peptides corresponding to regions of larger pineal proteins could influence gene expression in cells. Epitalon was framed as a synthetic analogue of an active fragment rather than a direct isolation product. Whether the tetrapeptide reproduces the effects of the parent extract is an open question, because comparative studies are limited and the parent extract itself is not a single defined substance.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C14H22N4O9 | Calculated from the four residues with three water losses |
| Molecular mass | About 390.35 g/mol | Monoisotopic mass near 390.14, used for mass-spectrometric identification |
| Peptide sequence | Ala-Glu-Asp-Gly | Single-letter form AEDG; no disulfide bonds or modified residues |
| Appearance | White to off-white solid | Supplied as a dried powder |
| Isoelectric point | Around 4 | Estimated from aspartate and glutamate side-chain pKa values |
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 compound is described in the literature as a derivative of epithalamin, a preparation obtained from bovine pineal tissue. Work on this peptide family was carried out mainly by a research group in Saint Petersburg beginning in the 1980s, and the substance was later registered for clinical use in Russia under the name Epitalon. Outside that region it is generally treated as a research chemical rather than an approved medicine. Statements about its biological activity rest on a relatively small number of studies, and independent replication remains limited.
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 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.
Chemically, the molecule consists of four amino acid residues joined by three peptide bonds, with a free N-terminal amino group and a free C-terminal carboxyl group. Its molecular formula is C14H22N4O9, and its monoisotopic mass is approximately 390 daltons. The acidic glutamate and aspartate side chains give the peptide a net negative charge near neutral pH, a property that shapes its chromatographic behaviour and solubility profile. No disulfide bridges or other post-translational modifications are present, so the primary sequence alone defines the structure.
Most experimental work has been carried out in cell culture and animal models. Several reports describe changes in telomerase activity and proliferation in cultured cells, while rodent studies have examined lifespan, melatonin rhythm and reproductive endpoints. Human data remain limited, and much of the published clinical material consists of small trials with incomplete reporting of methods and controls. Whether the cell and animal findings translate into measurable effects in people is an open question, and the mechanistic basis of the reported telomerase changes is not fully established.
Published work on this compound consists mainly of in vitro experiments, animal studies, and small clinical investigations, a substantial share of which appeared in Russian-language journals. Sample sizes are generally small, control conditions differ between studies, and several endpoints rely on markers whose clinical meaning is itself debated. Reviews of the longevity field treat the peptide as an early example of telomerase-directed research rather than an established intervention. Regulatory treatment varies by country: some jurisdictions place it under prescription controls, others treat it as a laboratory material, and importation may be restricted regardless of local status.
Epitalon is a synthetic tetrapeptide whose sequence is alanine–glutamate–aspartate–glycine, commonly abbreviated AEDG. It was developed in Russia during the 1980s and 1990s by investigators associated with the St. Petersburg Institute of Bioregulation and Gerontology, who studied short peptides as regulators of gene expression and tissue function. The alternative spelling epithalon appears interchangeably in the literature, and the two names refer to the same molecule. Outside Russia it is encountered chiefly as a research chemical rather than a licensed medicine, and it holds no approval from the United States Food and Drug Administration or the European Medicines Agency.
==== Translation ==== Two different sets of proteins are translated from viral mRNAs. The first set is represented by six structural proteins that include nucleocapsid protein (NP), phosphoprotein (P), matrix protein (M), fusion protein (F), neuraminidase (NA) and large protein (L). All these proteins have variable functions and are incorporated into the viral capsid (see the section "Virion structure" above). The second set is represented by seven non structural or accessory proteins. These proteins are translated from the polycistronic mRNA of P gene. This mRNA encodes eight translation products, and P-protein is only one of them. Alternative variants of translation are represented by V, W, C, C′, Y, Y′ and X proteins. The proteins C′, C, Y1, Y2 are products of mRNA alternative reading frame, they collectively referred as C-proteins or C-nested proteins and they share common C-terminal end. The X protein also shares the same C-terminal end and its translation also independently initiated by ribosomes. The proteins V and W are products of cotranscriptional mRNA editing. All these non-structural proteins have multiple functions, including the organization of viral RNA synthesis and helping the virus to infect host cells by escaping host innate immunity (see "Virus-induced immunosuppression" section above).
The study of pathology, including the detailed examination of the body, dissection and inquiry into specific maladies, dates back to antiquity. Rudimentary understanding of many conditions was present in most early societies and is attested to in the records of the earliest historical societies, including those of the Middle East, India, and China. By the Hellenic period of ancient Greece, a concerted causal study of disease was underway (see Medicine in ancient Greece), with many notable early physicians (such as Hippocrates, for whom the modern Hippocratic Oath is named) having developed methods of diagnosis and prognosis for a number of diseases. The medical practices of the Romans and those of the Byzantines continued from these Greek roots, but, as with many areas of scientific inquiry, growth in understanding of medicine stagnated somewhat after the Classical Era, but continued to slowly develop throughout numerous cultures. Notably, many advances were made in the medieval era of Islam (see Medicine in medieval Islam), during which numerous texts of complex pathologies were developed, also based on the Greek tradition. Even so, growth in complex understanding of disease mostly languished until knowledge and experimentation again began to proliferate in the Renaissance, Enlightenment, and Baroque eras, following the resurgence of the empirical method at new centers of scholarship.
The total synthesis of bottromycin was accomplished in 2009. The synthesis was achieved in 17 steps. Although bottromycin is a peptide-based natural product, it contains an unusual macrocycle and thiazole heterocycle, so that the total synthesis could not be accomplished using traditional solid-phase peptide synthesis. The synthesis was accomplished using a combination of peptide coupling and other methods. To obtain the primary thia-β-Ala-OMe intermediate, a sequence of condensation, Mannich reaction, and palladium-catalyzed decarboxylation steps were performed. This intermediate was prepared stereoselectively. To obtain the amidine linkage, a tripeptide intermediate was coupled to a phthaloyl-protected thioamide via mercury-mediated condensation using mercury (II) trifluoromethanesulfonate (Hg(OTf)2) to yield a branched amidine intermediate. To obtain the final product macrocycle, macrolactamization of the amidine-containing intermediate was required. Macrolactamization was performed with 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDCI) and iPr2NEt yielded the final product, bottromycin A2. To confirm that the synthesized bottromycin A2 had the same stereochemistry as natural bottromycin A2, the product was studied by optical rotation, 1H and 13C NMR, IR, and HRMS. The data was found to match that of isolated bottromycin A2. Further, the synthetic sample of bottromycin was also found to have antibacterial activity against both MRSA and VRE, although quantitative data was not reported.
Sertraline is a selective serotonin reuptake inhibitor (SSRI). By binding to the serotonin transporter (SERT) it inhibits neuronal reuptake of serotonin and potentiates serotonergic activity in the central nervous system. Over time, this leads to a downregulation of pre-synaptic 5-HT1A receptors, which is associated with an improvement in passive stress tolerance, and delayed downstream increase in expression of brain-derived neurotrophic factor (BDNF), which may contribute to a reduction in negative affective biases. It does not significantly affect histamine, acetylcholine, GABA or benzodiazepine receptors. Sertraline also shows relatively high activity as an inhibitor of the dopamine transporter (DAT) occupying ~20% of DAT receptors at doses 200mg and above, and antagonist of the sigma σ1 receptor (but not the σ2 receptor). However, sertraline affinity for its main target (SERT) is much greater than its affinity for σ1 receptor and DAT. Although there could be a role for the σ1 receptor in the pharmacology of sertraline, the significance of this receptor in its actions is unclear. Similarly, the clinical relevance of sertraline's blockade of the dopamine transporter is uncertain. Sertraline is a REDD1-dependent mTOR inhibitor. It blocks AKT/mTOR pathway and has autophagy-inducing activity.
Sources: en.wikipedia.org
In 2017, the United Nations conducted a Bayesian sensitivity analysis of global population burden based on life expectancy projection at birth in future decades. The 95% prediction interval of average life expectancy rises as high as 106 years old by 2090, with ongoing and layered effects on world population and demography should that happen. However, the prediction interval is extremely wide.
==== Necessary and sufficient conditions ==== Ajahn Brahm has argued that the Buddhist doctrine of conditionality includes two main elements of the logical concepts of conditionality: necessity and sufficiency. According to Brahm, "when this is, that is; from the arising of this, that arises." refers to a "sufficient condition" while "when this is not, that is not; from the ceasing of this, that ceases" refers to a "necessary condition". Like Brahm, Bodhi also argues that there are two main characterizations of conditionality in the early sources. One is positive, indicating "a contributory influence passing from the condition to the dependent state," while the other is negative, indicating "the impossibility of the dependent state appearing in the absence of its condition." He compares these two with the first and second phrases of the general principle definition respectively. Regarding the second, positive characterization, other early sources also state that a condition "originates (samudaya) the dependent state, provides it with a source (nidāna), generates it (jātika), gives it being (pabhava), nourishes it (āhāra), acts as its foundation (upanisā), causes it to surge (upayāpeti)" (see: SN 12.11, 23, 27, 66, 69). However, according to Harvey and Brahm, while the 12 nidanas are necessary conditions for each other, not all of them are necessary and sufficient conditions (some are, some are not). As Harvey notes, if this was the case, "when a buddha or arahat experienced feeling they would inevitably experience craving" (but they do not).
Receptors of a particular type are linked to specific cellular biochemical pathways that correspond to the signal. While numerous receptors are found in most cells, each receptor will only bind with ligands of a particular structure. This has been analogously compared to how locks will only accept specifically shaped keys. When a ligand binds to a corresponding receptor, it activates or inhibits the receptor's associated biochemical pathway, which may also be highly specialised. Receptor proteins can be also classified by the property of the ligands. Such classifications include chemoreceptors, mechanoreceptors, gravitropic receptors, photoreceptors, magnetoreceptors and gasoreceptors.
Portal is a 2007 puzzle-platform game developed and published by Valve. It was originally released in a bundle, The Orange Box, for Windows, Xbox 360 and PlayStation 3, and has been ported to other systems, including Mac OS X, Linux, Android (via Nvidia Shield), and Nintendo Switch. Portal is a first person game. It consists primarily of a series of puzzles that must be solved by teleporting the player's character and simple objects using the "Aperture Science Handheld Portal Device", also referred to as the "portal gun", a device that can create portals between locations in the puzzles. The player character, Chell, is challenged and taunted by an artificial intelligence construct named GLaDOS (Genetic Lifeform and Disk Operating System) to complete each puzzle in the Aperture Science Enrichment Center using the portal gun with the promise of receiving cake when all the puzzles are completed. The Source engine's physics system allows kinetic energy to be retained through portals, requiring creative use of portals to maneuver through the test chambers. This gameplay element is based on a similar concept from the game Narbacular Drop; many of the team members from the DigiPen Institute of Technology who worked on Narbacular Drop were hired by Valve for the creation of Portal. Portal was acclaimed as one of the most original games of 2007, despite some criticism for its short duration. It received praise for its originality, unique gameplay, dark story and sense of comedy.
== Membrane Characterization == After casting and synthesis of membrane there is need to characterize the prepared membrane to know more details about membrane parameters, like pore size, functional groups, wettability, surface charge, etc. It is important to know membrane properties so we are able to remove and treat a particulate pollutant, which causes pollution in the environment. For characterization following different instruments are used:
Sources: en.wikipedia.org
== Modes of industrial operation == Most industrial fermentation uses batch or fed-batch procedures, although continuous fermentation can be more economical if various challenges, particularly the difficulty of maintaining sterility, can be met.
=== Nuclear magnetic resonance spectroscopy === In NMR spectroscopy, e.g. of the nuclei 1H, 13C and 29Si, frequencies depend on the magnetic field, which is not the same across all experiments. Therefore, frequencies are reported as relative differences to tetramethylsilane (TMS), an internal standard that George Tiers proposed in 1958 and that the International Union of Pure and Applied Chemistry has since endorsed. The relative difference to TMS is called chemical shift. TMS works as an ideal standard because it is relatively inert and its identical methyl protons produce a strong upfield signal, isolated from most other protons. It is soluble in most organic solvents and is removable via distillation due to its low boiling point. In practice, the difference between the signals of common solvents and TMS are known. Therefore, no TMS needs to be added to commercial deuterated solvents, as modern instruments are capable of detecting the small quantities of protonated solvent present. By specifying the lock solvent to be used, modern spectrometers are able to correctly reference the sample; in effect, the solvent itself serves as the internal standard.
==== Attention deficit hyperactivity disorder (ADHD) ==== A meta-analysis of observational studies showed that children with ADHD have lower vitamin D levels and that there was a small association between low vitamin D levels at the time of birth and later development of ADHD. Several small, randomized controlled trials of vitamin D supplementation indicated improved ADHD symptoms such as impulsivity and hyperactivity.
== Etymology == The word amputation is borrowed from Latin amputātus, past participle of amputāre "to prune back (a plant), prune away, remove by cutting (unwanted parts or features), cut off (a branch, limb, body part)," from am-, assimilated variant of amb- "about, around" + putāre "to prune, make clean or tidy, scour (wool)". The English word "Poes" was first applied to surgery in the 17th century, possibly first in Peter Lowe's A discourse of the Whole Art of Chirurgerie (published in either 1597 or 1612); his work was derived from 16th-century French texts and early English writers also used the words "extirpation" (16th-century French texts tended to use extirper), "disarticulation", and "dismemberment" (from the Old French desmembrer and a more common term before the 17th century for limb loss or removal), or simply "cutting", but by the end of the 17th century "amputation" had come to dominate as the accepted medical term.
Sources: en.wikipedia.org
No. Epithalamin is a peptide-containing extract of bovine pineal glands, while epitalon is a single synthetic tetrapeptide. The extract contains many peptides and other tissue components, so its composition varies between batches in ways that a synthesised sequence does not.
It is not recognised as an endogenous peptide hormone. The four-residue sequence can appear inside larger proteins and in digestive fragments of dietary protein, but no dedicated pathway producing it as a signalling molecule has been identified.
Several cell-culture reports describe increased telomerase activity after treatment, measured by enzyme assays or by transcript levels. Results differ between cell types and laboratories, and measured telomere lengthening has been reported in some studies but not in others, which leaves the physiological relevance open.
Epitalon is a synthetic tetrapeptide composed of four amino acids: alanine, glutamate, aspartate, and glycine. It is written as Ala-Glu-Asp-Gly. The free peptide has a molecular weight of about 390 daltons and is normally supplied as a lyophilized powder.