Everything below concerns amino acid sequence. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2025-11-24. Numbers and descriptions here follow the published literature rather than marketing material.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter notation. Its structure consists of the immunomodulatory tetrapeptide tuftsin, Thr-Lys-Pro-Arg, extended at the carboxyl terminus by a Pro-Gly-Pro segment. The molecular formula is commonly given as C33H57N11O9, corresponding to a monoisotopic mass near 751.4 Da and an average molecular mass near 751.9 Da. All seven residues are proteinogenic amino acids, and the molecule carries no modified side chains or non-natural linkages.
The compound was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences during the 1980s and 1990s. The stated design goal was to retain the immunomodulatory and central nervous system activity attributed to tuftsin while improving resistance to enzymatic breakdown. Adding a proline-rich tail to the short parent peptide was a deliberate strategy, because proline residues restrict the conformations available to many peptidases. The same laboratory produced Semax, an ACTH fragment analog, and both compounds were developed in parallel as short, enzymatically stabilized peptides intended for intranasal use.
Selank is not a naturally occurring peptide and has no known endogenous counterpart in human physiology. Russian-language sources frequently call it TP-7, while English-language sources use the name Selank almost exclusively. Database indexing is uneven, partly because early reports appeared in regional journals that are not widely cataloged. Some summaries describe the material as a tuftsin analog and others as a synthetic heptapeptide; the labels overlap rather than conflict. Citing the primary sequence resolves ambiguity more reliably than the research or trade name alone.
Lyophilized selank is normally supplied as a dry powder and is considered stable for extended periods when kept cold and dry. Moisture uptake is the main practical threat, because absorbed water promotes both hydrolysis and aggregation in the solid state. Vials are usually warmed to room temperature before opening so that condensation does not form on the powder. Supplier documentation commonly specifies -20 °C for routine storage, with -80 °C used for material intended to be archived for years.
Once dissolved, the peptide is markedly less stable than the dry powder. Aqueous solutions are subject to backbone hydrolysis and to microbial growth when they are handled without sterile technique. Buffered solutions near neutral pH are common for short-term laboratory work, while acidic conditions are sometimes used to improve solubility. Analytical laboratories generally prepare working solutions fresh rather than storing them, and a residual water film left in a reopened vial can seed degradation even when the container appears dry.
| Property | Value | Notes |
|---|---|---|
| Peptide sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Seven residues; tuftsin plus a Pro-Gly-Pro tail |
| Molecular formula | C33H57N11O9 | Commonly reported value for the free peptide |
| Monoisotopic mass | Roughly 751.4 Da | Average molecular mass near 751.9 Da |
| Appearance | White to off-white powder | Typically supplied as a lyophilized solid |
| Solubility class | Freely soluble in water | Also dissolves in saline and other polar solvents |
Lyophilised material kept dry at minus 20 degrees Celsius or colder is the most stable form, and suppliers commonly state a shelf life of two years or more under those conditions. Once dissolved, degradation accelerates through hydrolysis and deamidation, particularly at alkaline pH or elevated temperature. Working solutions are usually divided into single-use aliquots to avoid repeated freeze-thaw cycles. The choice of reconstitution solvent affects both stability and the ionic strength of the final preparation.
Reverse-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometres is the standard purity method. Mass spectrometry, typically electrospray ionisation, confirms identity through the expected mass-to-charge pattern. Amino acid analysis can verify composition independently. Chiral purity requires separate techniques such as derivatisation followed by chromatographic separation, and such data are rarely reported for research-grade material.
Proposed mechanisms center on modulation of the GABA system, but no single molecular target has been confirmed. Rodent studies report changes in GABA-A receptor expression and in the turnover of serotonin, dopamine, and norepinephrine in several brain regions. Increases in brain-derived neurotrophic factor and its receptor have also been described after repeated administration. These findings come largely from animal models, and the degree to which they describe human neurochemistry remains an open question. The mechanism is best characterized as multi-system and not fully resolved.
Pharmacokinetic data are limited. Like most short peptides, Selank is vulnerable to plasma and tissue peptidases, and its measured half-life in circulation is short, on a minutes scale. The Pro-Gly-Pro tail slows this degradation but does not eliminate it. Intranasal administration is the route described in most reports, with absorption through the nasal mucosa and a hypothesized path into the central nervous system that avoids the blood-brain barrier. Direct measurements of human brain exposure are unavailable, so distribution claims rest on inference from animal work.
Clinical evidence comes mainly from small studies conducted in Russia, several of which were open-label or lacked robust blinding. Reported outcomes include lower anxiety scores, changes in attention measures, and effects on asthenic states following illness. Sample sizes are typically in the tens of participants, and independent replication outside the region is scarce. Reviews published in English generally note the limited methodological quality of the underlying trials. Whether the compound produces clinically meaningful effects under rigorous conditions remains unresolved.
Selank is a synthetic heptapeptide developed in Russia during the 1990s. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences designed it as a stabilized analog of tuftsin, a naturally occurring immunomodulatory tetrapeptide. The compound has been studied primarily for its reported anxiolytic and nootropic effects. It remains largely unknown in Western pharmacology and is not approved as a medicine by major regulators such as the FDA or the EMA.
The primary structure of Selank is Thr-Lys-Pro-Arg-Pro-Gly-Pro, corresponding to the molecular formula C33H57N11O9 and a monoisotopic mass of roughly 751.9 daltons. The N-terminal threonine and the arginine residue in the fourth position are shared with tuftsin, which carries the sequence Thr-Lys-Pro-Arg. The three additional residues at the C-terminus, Pro-Gly-Pro, extend the chain and are associated with greater resistance to enzymatic degradation. This extension also separates Selank from the shorter parent peptide.
Naming conventions place Selank in the same research family as Semax, another Russian-developed peptide investigated for cognitive effects. The two compounds share a lineage but differ in sequence and in the biological systems proposed as their targets. Semax descends from ACTH fragments, whereas Selank descends from tuftsin. Publications sometimes identify Selank by its full peptide sequence or by laboratory codes rather than one uniform trade name. Because replication outside Russia is limited, reports on its properties are best read alongside the study design and the purity of the material tested.
International Union of Biochemistry and Molecular Biology (IUBMB) An international non-governmental organization devoted to promoting scientific research and education in the disciplines of biochemistry and molecular biology, primarily by standardizing biochemical nomenclature, developing and publishing laboratory methods, and awarding grants and fellowships to students and researchers.
Originally this research on alternative forms of DNA was driven by the question of how life evolved on earth and why RNA and DNA were selected by (chemical) evolution over other possible nucleic acid structures. Two hypotheses for the selection of RNA and DNA as life's backbone are either they are favored under life on Earth's conditions, or they were coincidentally present in pre-life chemistry and continue to be used now. Systematic experimental studies aiming at the diversification of the chemical structure of nucleic acids have resulted in completely novel informational biopolymers. So far a number of XNAs with new chemical backbones or leaving group of the DNA have been synthesized, e.g.: hexose nucleic acid (HNA); threose nucleic acid (TNA), glycol nucleic acid (GNA) cyclohexenyl nucleic acid (CeNA). The incorporation of XNA in a plasmid, involving 3 HNA codons, has been accomplished already in 2003. This XNA is used in vivo (E coli) as template for DNA synthesis. This study, using a binary (G/T) genetic cassette and two non-DNA bases (Hx/U), was extended to CeNA, while GNA seems to be too alien at this moment for the natural biological system to be used as template for DNA synthesis. Extended bases using a natural DNA backbone could, likewise, be transliterated into natural DNA, although to a more limited extent. Aside being used as extensions to template DNA strands, XNA activity has been tested for use as genetic catalysts.
The rise of cyber as a warfighting domain has led to efforts to determine how cyberspace can be used to foster peace. For example, the German civil rights panel FIfF runs a campaign for cyberpeace − for the control of cyberweapons and surveillance technology and against the militarization of cyberspace and the development and stockpiling of offensive exploits and malware. Measures for cyberpeace include policymakers developing new rules and norms for warfare, individuals and organizations building new tools and secure infrastructures, promoting open source, the establishment of cyber security centers, auditing of critical infrastructure cybersecurity, obligations to disclose vulnerabilities, disarmament, defensive security strategies, decentralization, education and widely applying relevant tools and infrastructures, encryption and other cyberdefenses. The topics of cyber peacekeeping and cyber peacemaking have also been studied by researchers, as a way to restore and strengthen peace in the aftermath of both cyber and traditional warfare.
Sources: en.wikipedia.org
==== Household dust ==== PFOA is frequently found in household dust, making it an important exposure route for adults, but more substantially, children. Children have higher exposures to PFOA through dust compared to adults. Hand-to-mouth contact and proximity to high concentrations of dust make them more susceptible to ingestion, and increases PFOA exposure. One study showed significant positive associations were recognized between dust ingestion and PFOA serum concentrations. However, an alternate study found exposure due to dust ingestion was associated with minimal risk.
===== Fat-soluble vitamins ===== Vitamin A is required in kitten diets because cats cannot convert carotenes to retinol in the intestinal mucosa due to a lack of the necessary enzyme; therefore, this vitamin must be supplied in the diet. Vitamin E is another required vitamin in kitten diets; deficiency leads to steatitis, causing the depot fat to become firm and yellow-orange in colour, which is painful and leads to death. Also, vitamin D is essential because cats cannot convert it from precursors in the skin.
The commission was reconstituted and scaled down by the then environment secretary John Gummer in 1995. In the summer of 1991 Heseltine also launched a City Challenge process, whereby cities competed for government grants for capital projects, and played a key role in Major's decision to back Manchester's (unsuccessful as it turned out) bid to host the 1996 Olympic Games. He also proposed plans for developing an East Thames corridor (christened "Hezzaville" or "Heseltown" by the media). Heseltine received a standing ovation at the October 1991 Party Conference, seen as a sign of his rehabilitation with party activists, and was included on the A-Team to prepare for the 1992 election. He mocked Shadow Chancellor John Smith's "prawn cocktail offensive" to try to butter up City opinion ("Never have so many crustaceans died in vain"). He was a leading performer in the election and it was felt that had the Conservatives lost he might well have won the party leadership and been Leader of the Opposition, while if they won he would probably be given Trade and Industry, the job he had always wanted.
=== Bi–Bo === Klaus Biemann (1926–2016). Austrian chemist at MIT, the "father of organic mass spectrometry" and particularly noted for his role in advancing protein sequencing with tandem mass spectrometry. Member Natl. Acad. Sci. USA. Ethel Ronzoni Bishop (1890–1975). American biochemist and physiologist at Washington University in St. Louis who studied carbohydrate metabolism. Pamela J. Bjorkman (b. 1956). American biochemist at Caltech, who studies immune recognition of viral pathogens. Member Natl. Acad. Sci. USA. Elizabeth Blackburn AC FRS FAA FRSN (b. 1948). Australian-American biochemist, Nobel Laureate, co-discoverer of telomerase. Konrad Emil Bloch FRS (1912–2000). German-American biochemist at Harvard, who worked on the mechanism and regulation of cholesterol and fatty acid metabolism. Nobel Prize in Physiology or Medicine 1964. Elkan Blout (1919–2006). American biochemist at Harvard, who worked on peptide structure and conformation, including cyclic peptides. Member Natl. Acad. Sci. USA. David Mervyn Blow FRS (1931–2004). British X-ray crystallographer at Imperial College London, who worked on protein structure. Tom Blundell, FRS (b. 1942). British biochemist at the University of Cambridge, structural biologist, and science administrator. Aaron Bodansky (1887–1960). Russian-born American biochemist at the Hospital for Joint Diseases, New York, specializing in the area of calcium metabolism. Paul D. Boyer (1918–2018). American biochemist, at UCLA who studied ATP synthase. Nobel Prize in Chemistry in 1997. Member Natl. Acad. Sci. USA.
Sources: en.wikipedia.org
elegans this initiation response is amplified through the synthesis of a population of 'secondary' siRNAs during which the Dicer-produced initiating or 'primary' siRNAs are used as templates. These 'secondary' siRNAs are structurally distinct from Dicer-produced siRNAs and appear to be produced by an RNA-dependent RNA polymerase (RdRP).
A parathyroid adenoma is the most common cause of hyperparathyroidism. They are more commonly found in women than in men. In this form, the chief cells mutate to exhibit multiple nuclei. Chief cells in parathyroid adenomas also display acid phosphatase activity. It is a benign tumor of the gland that requires surgical removal. These benign adenomas are typically affect only one or two of the parathyroid glands, known respectively as a single adenoma or double adenoma. Typically, no disease is linked to the cause. A primary adenoma can only develop as a primary cause.
=== Medications === Medications that lower fevers are called antipyretics. The antipyretic ibuprofen is effective in reducing fevers in children. It is more effective than acetaminophen (paracetamol) in children. Ibuprofen and acetaminophen may safely be used together in children with fevers. The efficacy of acetaminophen by itself in children with fevers has been questioned. Ibuprofen is also superior to aspirin in children with fevers. Additionally, aspirin is not recommended in those under the age of 18 due to the risk of Reye's syndrome. Using both paracetamol and ibuprofen at the same time or alternating between the two is more effective at decreasing fever than using only paracetamol or ibuprofen. It is not clear if it increases child comfort. Response or nonresponse to medications does not predict whether or not a child has a serious illness. With respect to the effect of antipyretics on the risk of death in those with infection, studies have found mixed results, as of 2019.
Sources: en.wikipedia.org
The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter code. It combines the tetrapeptide tuftsin with a carboxyl-terminal Pro-Gly-Pro extension. This full sequence identifies the molecule more precisely than the research name.
No peptide with this exact sequence has been identified as an endogenous substance. It is a laboratory-designed analog of tuftsin, a naturally occurring immunomodulatory tetrapeptide. The Pro-Gly-Pro extension has no known natural source.
Proline introduces conformational constraints that make a peptide less accessible to common peptidases. This is a standard stabilization strategy in peptide design. The added residues also increase the distance between the active tuftsin portion and typical cleavage sites.
Sealed, desiccated storage at -20 °C or colder is the standard recommendation for research-grade material. Vials should reach room temperature before they are opened, which limits condensation. Repeated temperature cycling is discouraged.