A practical reference on research chemical: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-07-26 and is reviewed periodically as new material appears.
（TG:@pojiaai）Epitalon is a synthetic linear tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, abbreviated AEDG. It emerged from work on epithalamin, a peptide fraction prepared from bovine pineal tissue, and was designed as a short, chemically defined analogue of that extract. Early publications came mainly from Russian laboratories studying pineal peptides and aging-related endpoints. The compound appears in the literature under several spellings, including epithalon and epithalone, which complicates systematic searching. Its small size makes solid-phase assembly and routine analytical characterization straightforward.
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.
Epitalon appears in the literature primarily through a small number of research groups, most of them associated with the St. Petersburg Institute of Bioregulation and Gerontology. Publications describe cell culture experiments, animal studies, and a limited number of small human studies. Independent replication outside this network is sparse. As a result, reviews of the topic usually separate descriptive reports of observed effects from the question of whether those effects generalize, and they note the difficulty of comparing studies that use different preparations and endpoints.
Analytical characterization of epitalon relies on standard peptide methods. Reverse-phase high-performance liquid chromatography is used to assess purity, and mass spectrometry confirms identity by checking the observed mass against the expected value near 390 daltons. Amino acid analysis can verify composition. Because the peptide is short and hydrophilic, it elutes early on many reverse-phase columns, so method development often requires ion-pairing reagents to achieve adequate retention and resolution from related impurities.
Storage and handling follow conventional peptide practice. Lyophilized epitalon is typically kept refrigerated or frozen, protected from moisture and light, and allowed to equilibrate to room temperature before opening to avoid condensation. Once dissolved, aqueous solutions are usually stored cold and used within a short period, since dilute peptide solutions can support microbial growth and may slowly degrade. The absence of cysteine and methionine reduces, but does not eliminate, oxidation concerns during long-term storage.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Linear tetrapeptide | Four residues joined by three peptide bonds |
| Sequence | Ala-Glu-Asp-Gly | Commonly abbreviated AEDG |
| Molecular formula | C14H22N4O9 | Free acid form |
| Monoisotopic mass | Approximately 390 Da | Matches values reported from mass spectrometry |
| Net charge near neutral pH | Negative | Contributed by glutamate and aspartate side chains |
Epitalon is a synthetic tetrapeptide whose four residues are alanine, glutamate, aspartate and glycine, commonly abbreviated AEDG. Its molecular formula is C14H22N4O9 and its monoisotopic mass is near 390.35 daltons. The peptide carries two acidic side chains, so it is neutral to negatively charged in most aqueous buffers. Published reference summaries usually list it under both spellings, epitalon and epithalon, and treat the two names as the same material.
The compound is generally described as a synthetic analogue of a fragment isolated from a pineal gland extract. Researchers associated with the Saint Petersburg Institute of Bioregulation and Gerontology introduced it during the 1980s and 1990s while studying short peptides from animal tissue. The original extract, called epithalamin, is a heterogeneous mixture, whereas epitalon is a single defined sequence. That distinction matters because findings reported for the extract are not automatically findings about the pure tetrapeptide, and claims about broader biological effects remain a separate question from the chemical identity described here.
The most frequently cited laboratory finding is that AEDG increased telomerase activity and extended telomere length in cultured human somatic cells. That work used fetal fibroblast strains and reported changes in enzyme activity alongside altered division counts. Replication by unrelated groups has been limited, and the published record is largely a single-laboratory series rather than a multi-centre programme. The result supports a hypothesis about peptide influence on gene expression in cell culture; it does not by itself establish an effect on telomere length in living animals or in people.
Animal and clinical reports appear mainly in Russian-language journals from the 1990s and 2000s, covering endpoints such as melatonin rhythm, lifespan in aged rodents, and retinal function. Many of these papers involve small groups, lack blinding or placebo comparison, and are difficult to retrieve through indexed databases. Review articles published in English generally summarise the claims without reanalysing the underlying data. Because no large randomised trial exists, the clinical importance of these reported effects stays unresolved and is properly described as an open question.
The comparatively low molecular mass leads to a better permeability in tissues, and to a short plasma half-life since they are eliminated renally. Unlike whole antibodies, they do not show complement system triggered cytotoxicity because they lack an Fc region. Camelid and fish derived sdAbs are able to bind to hidden antigens that are not accessible to whole antibodies, for example to the active sites of enzymes. This property has been shown to result from their extended CDR3 loop, which is able to penetrate such buried sites.
== Biography == Woodroof was born in Dallas, Texas, on February 3, 1950, to Garland Odell Woodroof (March 17, 1917, in Texas – December 3, 1983, in Dallas) and Willie Mae Hughes (November 25, 1917, in Oklahoma – November 19, 1996, in Dallas). His first marriage was to Mary Etta Pybus on June 28, 1969, in Dallas; they had a daughter. They divorced on March 23, 1972. On May 6, 1972, he married a woman named Rory S. Flynn in Dallas. They divorced on May 21, 1973. He then married Brenda Shari Robin on October 4, 1982, in Lubbock. They divorced on March 4, 1986, after he was diagnosed with HIV. It was recorded that Woodroof had a mercurial personality. One reporter writes that "Woodroof took guns to his doctor’s office, prompting Steven Pounders to 'fire him as a patient.'" Woodroof later sent the doctor roses, and the doctor took him back. Woodroof was said to have lost all his friends after they found out he was HIV-positive. The movie Dallas Buyers Club depicts Woodroof as holding homophobic views prior to contracting HIV. Other people who knew Woodroof said that he did not harbor anti-gay beliefs and was openly bisexual. He was a member of the Dallas Gay Alliance.
He sailed for New York on the RMS Caronia on 19 September 1925, intending to study under Robert Chambers at Cornell University Medical College, but the micromanipulator he required for his research on the blood vessels of the brain was not available, so he arranged to work at the laboratory of Alfred Newton Richards at the University of Pennsylvania. He finally joined Chambers in March 1926. He hoped to be able to return to the UK via Australia and marry Ethel Reed in Adelaide, but in November 1925 he accepted an offer of a research position at London Hospital. The position came with five years' tenure and a salary of £850 per annum (equivalent to £45,000 in 2025), but they wanted him to start immediately. Florey managed to negotiate a delay, but only until May 1926. He returned to the UK on 13 May. Ethel joined him there in September, and they were married at Holy Trinity, Paddington, on 19 October.
Sources: en.wikipedia.org
Bioprinting also has possible uses in the future in assisting in wastewater treatment and in corrosion control. When humans come in contact with environmental biofilms, it is possible for infections and long-term health hazards to occur. Antibiotic penetration and expansion within a biofilm is an area of research which can benefit from bioprinting techniques, to further explore the effect of environmental biofilms on human health. Biofilm printing requires further research due to limited published data and complex protocols. 3D printing Bio-printing Biofabrication Cultured meat Ethics of bioprinting Regenerative medicine Bioinks
Osmium (76Os) has seven naturally occurring isotopes, five of which are stable: 187Os, 188Os, 189Os, 190Os, and (most abundant) 192Os. The other natural isotopes, 184Os and 186Os, have extremely long half-lives (1.12×1013 years and 2.0×1015 years, respectively) and for practical purposes can be considered to be stable as well. 187Os is the daughter of 187Re (half-life 4.12×1010 years) and is most often measured by the 187Os/188Os ratio. This ratio, as well as the 187Re/188Os ratio, have been used extensively in dating terrestrial as well as meteoric rocks. It has also been used to measure the intensity of continental weathering over geologic time and to fix minimum ages for stabilization of the mantle roots of continental cratons. There are also 31 artificial radioisotopes, the longest-lived of which are 194Os with a half-life of 6.0 years, 185Os with 92.95 days, and 191Os with 14.99 days; others are under 30 hours, with most under seven minutes. There are also 19 listed nuclear isomers, the longest-lived of which is 191mOs with a half-life of 13.10 hours. All isotopes and nuclear isomers of osmium are either radioactive or observationally stable, meaning that they are predicted to be radioactive but no actual decay has been observed.
14 September NASA releases its first public study on UAP (also known as UFOs), and appoints Mark McInerney as the first Director of UAP, to scientifically and transparently study further such occurrences. A new record time for quantum coherence is reported, with a single-photon qubit encoded in a novel superconducting cavity for 34 milliseconds. A genetically engineered marine microorganism is shown to break down polyethylene terephthalate in salt water. This plastic, used in everything from water bottles to clothing, is a significant contributor to microplastic pollution in oceans. A study finds that rivers are warming and losing oxygen faster than oceans. Of nearly 800 rivers, warming occurred in 87% and oxygen loss occurred in 70%. The study projects that within 70 years, river systems could "induce acute death" and extinctions of aquatic species due to long low oxygen levels. Astronomers report studies related to the Hubble tension, a disagreement in results attempting to measure the Hubble constant, and find that the results from the James Webb Space Telescope support earlier results from the Hubble Space Telescope. According to astronomer Adam Riess, "With Webb confirming the measurements from Hubble, the Webb measurements provide the strongest evidence yet that systematic errors in Hubble's Cepheid photometry do not play a significant role in the present Hubble tension ...
Sources: en.wikipedia.org
It is a synthetic tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, often abbreviated AEDG. The molecule is linear and contains no modified residues, so it is fully described by its sequence.
The compound came out of work on epithalamin, a peptide preparation derived from pineal tissue, conducted largely in Russian laboratories. Later studies in other countries examined it mainly in cell cultures and animal models.
The tetrapeptide sequence is a synthetic construct rather than a described circulating peptide. It was derived by analogy to peptide fractions obtained from tissue extracts, not isolated from blood or tissue as such.
Identity is normally confirmed by mass spectrometry, which checks the measured mass against the expected value near 390 daltons. Reverse-phase high-performance liquid chromatography is used alongside it to assess purity. Amino acid analysis can provide additional composition data.