A practical reference on Telomerase induction: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2025-09-20. Anything still debated is marked as such rather than presented as settled.
Published evidence comes mainly from Russian-language journals and from a single research group, with small sample sizes and limited independent replication. A few laboratories outside that group have examined related peptides and reported weaker or absent telomerase effects, so the central claim is best described as contested rather than settled. Rodent studies report modest changes in some ageing markers and in survival, but designs vary and control conditions are often sparse. No large randomised trial in humans has been published, and long-term safety data in healthy populations are correspondingly thin.
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.
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.
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.
| 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 |
The Salmonella Mutagenesis test (Ames test) uses multiple strains of Salmonella typhimurium that are auxotrophic to histidine to test whether a given chemical can cause mutations by observing its auxotrophic property in response to an added chemical compound. The mutation a chemical substance or compound causes is measured by applying it to the bacteria on a plate containing histidine then moving the bacteria to a new plate without sufficient histidine for continual growth. If the substance does not mutate the genome of the bacteria from auxotrophic to histidine back to prototrophic to histidine, then the bacteria would not show growth on the new plate. So by comparing the ratio of the bacteria on the new plate to the old plate and the same ratio for the control group, it is possible to quantify how mutagenic a substance is, or rather, how likely it is to cause mutations in DNA. A chemical is considered positive for Ames test if it causes mutations increasing the observed reversion rate and negative if presents similar to the control group. There is a normal, but small, number of revertant colonies expected when an auxotrophic bacteria is plated on a media without the metabolite it needs because it could mutate back to prototrophy. The chances of this are low and therefore cause very small colonies to be formed. If a mutagenic substance is added, however, the number of revertants would be visibly higher than without the mutagenic substance.
=== Protein purification === Polyhistidine-tags are often used for affinity purification of polyhistidine-tagged recombinant proteins expressed in Escherichia coli or other expression systems. Typically, cells are harvested via centrifugation and the resulting cell pellet lysed either by physical means or by means of detergents and enzymes such as lysozyme or any combination of these. At this stage, the lysate contains the recombinant protein among many endogenous proteins originating from the host cells. The lysate is exposed to affinity resin bound to a carrier matrix coupled with a divalent cation, either by direct addition of resin (batch binding) or by passing over a resin bed in a column format. The resin is then washed with buffer to remove proteins that do not specifically interact with bound cation and the protein of interest is eluted off the resin using buffer containing a high concentration of imidazole or a lowered pH. The purity and amount of protein can be assessed by methods such SDS-PAGE and Western blotting. Affinity purification using a polyhistidine-tag usually results in relatively pure protein. Protein purity can be improved by the addition of a low (20-40 mM) concentration of imidazole to the binding and/or wash buffers. However, depending on the requirements of the downstream application, further purification steps using methods such as ion exchange or size exclusion chromatography may be required. IMAC resins typically retain several prominent endogenous proteins as impurities. In E.
Other hormones (stimulating- or releasing -hormones) Plasma concentrations of ions or nutrients, as well as binding globulins Neurons and mental activity Environmental changes, e.g., of light or temperature One special group of hormones is the tropic hormones that stimulate the hormone production of other endocrine glands. For example, thyroid-stimulating hormone (TSH) causes growth and increased activity of another endocrine gland, the thyroid, which increases output of thyroid hormones. To release active hormones quickly into the circulation, hormone biosynthetic cells may produce and store biologically inactive hormones in the form of pre- or prohormones. These can then be quickly converted into their active hormone form in response to a particular stimulus. Eicosanoids are considered to act as local hormones. They are considered to be "local" because they possess specific effects on target cells close to their site of formation. They also have a rapid degradation cycle, making sure they do not reach distant sites within the body. Hormones are also regulated by receptor agonists. Hormones are ligands, which are any kinds of molecules that produce a signal by binding to a receptor site on a protein. Hormone effects can be inhibited, thus regulated, by competing ligands that bind to the same target receptor as the hormone in question. When a competing ligand is bound to the receptor site, the hormone is unable to bind to that site and is unable to elicit a response from the target cell. These competing ligands are called antagonists of the hormone.
They met personally for the last time in September 1913 at the Fourth International Psychoanalytical Congress in Munich. Jung gave a talk on psychological types, the introvert and extraverted types, in analytical psychology. It was the publication of Jung's book The Psychology of the Unconscious in 1912 that led to the final break with Freud. The letters they exchanged at the time show Freud's refusal to consider Jung's ideas. This rejection caused what Jung described in his posthumously published autobiography, Memories, Dreams, Reflections (1962) as a "resounding censure". However, the exact reasons for this final break between the two is debated between Jungians and Freudians to this day. After the culminating break in 1913, Jung went through a period of psychological strain and transformation. Henri Ellenberger called Jung's intense experience a "creative illness" and compared it favourably to Freud's own period of what he called neurasthenia and hysteria.
Sources: en.wikipedia.org
For separation, the denatured samples are loaded onto a gel of polyacrylamide, which is placed in an electrophoresis buffer with suitable electrolytes. Thereafter, a voltage (usually around 100 V, 10-20 V per cm gel length) is applied, which causes a migration of negatively charged molecules through the gel in the direction of the positively charged anode. The gel acts like a sieve. Small proteins migrate relatively easily through the mesh of the gel, while larger proteins are more likely to be retained and thereby migrate more slowly through the gel, thereby allowing proteins to be separated by molecular size. The electrophoresis lasts between half an hour to several hours depending on the voltage and length of gel used. The fastest-migrating proteins (with a molecular weight of less than 5 kDa) form the buffer front together with the anionic components of the electrophoresis buffer, which also migrate through the gel. The area of the buffer front is made visible by adding the comparatively small, anionic dye bromophenol blue to the sample buffer. Due to the relatively small molecule size of bromophenol blue, it migrates faster than proteins. By optical control of the migrating colored band, the electrophoresis can be stopped before the dye and also the samples have completely migrated through the gel and leave it. The most commonly used method is the discontinuous SDS-PAGE.
Nanowires and nanotubes: The elastic moduli of some nanowires namely lead and silver, decrease with increasing diameter. This has been associated with surface stress, oxidation layer, and surface roughness. However, the elastic behavior of ZnO nanowires does not get affected by surface effects but their fracture properties do. So, it is generally dependent on material behavior and their bonding as well. The reason why mechanical properties of nanomaterials are still a hot topic for research is that measuring the mechanical properties of individual nanoparticles is a complicated method, involving multiple control factors. Nonetheless, Atomic force microscopy has been widely used to measure the mechanical properties of nanomaterials. Adhesion and friction of nanoparticles When talking about the application of a material adhesion and friction play a critical role in determining the outcome of the application. Therefore, it is critical to see how these properties also get affected by the size of a material. Again, AFM is a technique most used to measure these properties and to determine the adhesive strength of nanoparticles to any solid surface, along with the colloidal probe technique and other chemical properties. Furthermore, the forces playing a role in providing these adhesive properties to nanomaterials are either the electrostatic forces, VdW, capillary forces, solvation forces, structure force, etc.
Gershwin Prize for Popular Song, was launched in 2007 to honor the work of an artist whose career reflects lifetime achievement in song composition. Winners have included Paul Simon, Stevie Wonder, Paul McCartney, Burt Bacharach and Hal David, Carole King, Billy Joel, and Willie Nelson, as of 2015. The library also launched the Living Legend Awards in 2000 to honor artists, activists, filmmakers, and others who have contributed to America's diverse cultural, scientific, and social heritage; Fiction Prize (now the Library of Congress Prize for American Fiction) was started in 2008 to recognize distinguished lifetime achievement in the writing of fiction. World Digital Library, established in association with UNESCO and 181 partners in 81 countries in 2009, makes copies of professionally curated primary materials of the world's varied cultures freely available online in multiple languages. National Jukebox, launched in 2011, provides streaming free online access to more than 10,000 out-of-print music and spoken-word recordings. BARD was started in 2013; it is a digital, talking books mobile app for braille and audio reading downloads, in partnership with the library's National Library Service for the Blind and Print Disabled. It enables free downloads of audio and braille books to mobile devices via the Apple App Store. During Billington's tenure, the library acquired General Lafayette's papers in 1996 from a castle at La Grange, France; they had previously been inaccessible.
=== Risk factors === A number of factors can potentially increase the risk of developing paracetamol toxicity. Chronic excessive alcohol consumption can induce CYP2E1, thus increasing the potential toxicity of paracetamol. In one study of patients with liver injury, 64% reported alcohol intakes of greater than 80 grams a day, while 35% took 60 grams a day or less. Whether chronic alcoholism should be considered a risk factor has been debated by some clinical toxicologists. For chronic alcohol users, acute alcohol ingestion at the time of a paracetamol overdose may have a protective effect. For non-chronic alcohol users, acute alcohol consumption had no protective effect. Fasting is a risk factor, possibly because of depletion of liver glutathione reserves. The concomitant use of the CYP2E1 inducer isoniazid increases the risk of hepatotoxicity, though whether 2E1 induction is related to the hepatotoxicity in this case is unclear. Concomitant use of other drugs that induce CYP enzymes, such as antiepileptics including carbamazepine, phenytoin, and barbiturates, have also been reported as risk factors.
Ablukast (INN) is an experimental drug that is a leukotriene antagonist. It was investigated for potential applications in the treatment of inflammatory conditions, including asthma, skin disorders, and inflammatory bowel disease. It reached Phase III clinical trials, but development was discontinued in 1996.
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.
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.