Regulatory peptide is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Updated 2025-08-31. Numbers and descriptions here follow the published literature rather than marketing material.
Published clinical work is concentrated in Russian-language journals and generally involves small samples without independent replication. Systematic reviews in English note the shortage of randomised, placebo-controlled trials and the difficulty of verifying methods from translated reports. Outcome measures vary between studies, which complicates pooling of results. Interest in the compound as a cognitive or anxiolytic agent therefore rests on a thinner evidence base than the volume of citations suggests. Replication in well-powered trials with preregistered endpoints would be needed before firm conclusions about efficacy can be drawn.
Proposed mechanisms centre on the GABAergic system. Animal and tissue studies report changes in GABA-A receptor expression and reduced activity of GABA transaminase, the enzyme that degrades GABA. Effects on monoamine turnover, including serotonin and dopamine pathways, are also described, and a separate line of work links the peptide to increased expression of brain-derived neurotrophic factor in hippocampal tissue. Most of these findings come from rodent models and cell preparations. How the individual observations combine into a single coherent mode of action is not settled.
Published clinical evidence is limited. Most controlled trials were conducted in Russia, enrolled modest numbers of participants, and appeared in Russian-language journals, which restricts independent verification. Reported outcomes include lower anxiety scores, improved attention and memory measures, and changes in fatigue ratings. Reviews written in English note methodological limitations such as small samples and inconsistent endpoints. Whether the compound produces clinically meaningful benefit relative to established anxiolytics is therefore an open question rather than an established finding.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences as a structural analogue of tuftsin, a naturally occurring tetrapeptide fragment of the immunoglobulin heavy chain. The added Pro-Gly-Pro tail was intended to slow enzymatic degradation and extend biological activity. In Russia it is registered as an anxiolytic nasal preparation, while regulators elsewhere have not approved it for clinical use.
Proposed mechanisms centre on modulation of the GABAergic system, with reports of altered expression of genes related to GABA-A receptor subunits and changed monoamine turnover. Some studies describe inhibition of enkephalinase, the enzyme that degrades endogenous enkephalins, which may prolong opioid peptide signalling. Effects on brain-derived neurotrophic factor and on cytokine expression have also been reported. These findings come largely from animal models and small human studies, and the precise primary target remains unresolved.
| Property | Value | Notes |
|---|---|---|
| Primary route studied | Intranasal | Also examined parenterally in animal work |
| Reported plasma half-life | Minutes to tens of minutes | Values vary widely between reports |
| Main model systems | Rodent behavioural and cell assays | Human trials are few and small |
| Principal proposed targets | GABA-A receptor, GABA transaminase | Monoamine and neurotrophic pathways also reported |
| Evidence grade | Preliminary | Limited independent replication |
Tuftsin, the parent structure, is a naturally occurring immunomodulatory tetrapeptide released from the Fc region of immunoglobulin G by spleen enzymes. Selank extends this four-residue sequence with three additional amino acids. The stated rationale is that the added tail slows enzymatic breakdown and may influence receptor interactions. How the full heptapeptide behaves at the molecular level is not firmly established, and proposed mechanisms often involve indirect modulation of neurotransmitter or immune signaling rather than a single defined target.
Selank is a synthetic heptapeptide developed in Russia. Its sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, a seven-residue chain built around the natural tetrapeptide tuftsin. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences first described the compound in the mid-1990s. The design combined the tuftsin core with an added Pro-Gly-Pro tail, a modification intended to extend the molecule's stability in biological fluids. Published work on the peptide has appeared mainly in Russian-language journals.
Reported activity for Selank centers on anxiolytic and nootropic effects. Russian clinical reports describe use in anxiety and in cognitive or attention-related complaints. Most of this evidence comes from studies conducted by the same research groups that developed the peptide. Independent replication in other countries remains limited, and no major Western regulatory agency has approved the compound for any indication. The gap between local reports and external verification is a recurring point in discussions of the peptide.
Peptide bonds in selank are susceptible to hydrolysis under strongly acidic or basic conditions, and the terminal proline residues are vulnerable to exopeptidase activity in biological samples. Lyophilized powder stored dry at -20 °C typically remains stable for extended periods, whereas aqueous solutions degrade faster and may lose measurable purity within days to weeks depending on pH, temperature, and microbial load. Repeated freeze-thaw cycles promote aggregation and adsorption to container surfaces. For analytical work, solutions are usually prepared fresh, kept cold, and used within a single working day.
Handling follows standard practice for research peptides. Material is weighed in a low-humidity environment because the powder absorbs atmospheric moisture. Purity is reported as the percentage area of the main peak in a chromatogram, with specifications commonly set at 95 percent or higher; values below that threshold indicate the presence of truncated or modified species. Residual trifluoroacetate from purification is often present and may affect mass balance. Certificates of analysis should state the analytical method, the column and gradient used, and the lot-specific retention time so that results can be compared across suppliers.
Identity and purity of selank are established with reversed-phase high-performance liquid chromatography coupled to mass spectrometry. The peptide elutes from C18 columns with acetonitrile gradients in water containing trifluoroacetic acid or formic acid, and detection is usually performed by ultraviolet absorbance near 214 nm. Electrospray ionization in positive mode gives a doubly protonated ion near m/z 377, consistent with a mass of about 752 Da. Amino acid analysis or tandem mass spectrometry of fragment ions confirms the sequence. Because the molecule has no aromatic residues, it lacks a usable 280 nm chromophore, so low-wavelength detection or mass spectrometry is required.
Purity assessment relies mainly on reverse-phase high-performance liquid chromatography with ultraviolet detection. Because the peptide lacks a strong chromophore, detection often uses backbone absorbance near 214 nm. Identity is confirmed by mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, comparing the measured mass against the expected value. Amino acid analysis can verify composition after acid hydrolysis. Diastereomer content and residual counterions are reported less often, although both can influence biological assays.
Lyophilized material is generally stable for extended periods when kept dry at or below minus twenty degrees Celsius. Working solutions are less stable, and common practice is to aliquot and freeze them so that repeated freeze-thaw cycles are avoided. Aqueous solutions are sensitive to pH extremes and to microbial growth, so short-term storage at refrigerator temperature is typical. Oxidation and hydrolysis are the principal degradation routes. Reconstitution with sterile water or a mild buffer is standard, and solutions should be protected from light.
Natural fibers are also used in composite materials, much like synthetic or glass fibers. These composites, called biocomposites, are a natural fiber in a matrix of synthetic polymers. One of the first biofiber-reinforced plastics in use was a cellulose fiber in phenolics in 1908. Usage includes applications where energy absorption is important, such as insulation, noise absorbing panels, or collapsable areas in automobiles. Natural fibers can have different advantages over synthetic reinforcing fibers. Most notably they are biodegradable and renewable. Additionally, they often have low densities and lower processing costs than synthetic materials. Design issues with natural fiber-reinforced composites include poor strength (natural fibers are not as strong as glass fibers) and difficulty with actually bonding the fibers and the matrix. Hydrophobic polymer matrices offer insufficient adhesion for hydrophilic fibers.
=== Triplexfpp === Triplexfpp is based on deep learning methods. This Python-based pipeline can help predict the most likely triplex-forming lncRNA. However since the lncRNA for training is limited, there is a long way to go before machine learning and deep learning methods can be applied.
Per Mendeleev's nomenclature for unnamed and undiscovered elements, flerovium is sometimes called eka-lead. In 1979, IUPAC published recommendations according to which the element was to be called ununquadium (symbol Uuq), a systematic element name as a placeholder, until the discovery of the element is confirmed and a permanent name is decided on. Most scientists in the field called it "element 114", with the symbol of E114, (114) or 114. Per IUPAC recommendations, the discoverer(s) of a new element has the right to suggest a name. After IUPAC recognized the discovery of flerovium and livermorium on 1 June 2011, IUPAC asked the discovery team at JINR to suggest permanent names for the two elements. The Dubna team chose the name flerovium (symbol Fl), after Russia's Flerov Laboratory of Nuclear Reactions (FLNR), named after Soviet physicist Georgy Flyorov (also spelled Flerov); earlier reports claim the element name was directly proposed to honour Flyorov. In accordance with the proposal received from the discoverers, IUPAC officially named flerovium after Flerov Laboratory of Nuclear Reactions, not after Flyorov himself. Flyorov is known for writing to Joseph Stalin in April 1942 and pointing out the silence in scientific journals in the field of nuclear fission in the United States, Great Britain, and Germany. Flyorov deduced that this research must have become classified information in those countries. Flyorov's work and urgings led to the development of the USSR's own atomic bomb project.
Israeli airstrikes hit Iranian oil storage facilities, killing four people. Strikes on fuel depots near Tehran caused a "river of fire" to pour out along the streets, and the city became engulfed in thick black smoke, causing toxic acidic rain to fall in the surrounding area. US Central Command announced the death of a seventh US service member from an Iranian attack. The UK confirmed its forces had intercepted an Iranian drone headed towards Iraq, and declared its intention to send a Merlin helicopter to the region to detect aerial threats. According to the Iranian Red Crescent Society, 65 schools and 32 medical facilities had been targeted, and more than 10,000 civilian sites damaged. On 9 March, NATO confirmed the interception of a second ballistic missile in Turkish airspace. Turkey deployed six F-16s and air defense systems to Northern Cyprus. Trump claimed that "the war is very complete, pretty much", after speaking with Russian president Putin, and said "we already won the war in many ways." Following Syrian president Ahmed al-Sharaa's support for Lebanon's objective to disarm Hezbollah, the group targeted the city of Inkhil in Syria. About a dozen B-1B bombers arrived at bases in Europe.
Some motorcyclists favor kangaroo leather for motorcycle leathers because of its light weight and abrasion resistance. Kangaroo leather is also used for falconry jesses, soccer footwear, (e.g. Adidas Copa Mundial) and boxing speed bags.
Sources: en.wikipedia.org
Pictures, movies and applets showing the anatomy of Mus musculus, from www.digimorph.org Michael Purdy: "Researchers add mice to list of creatures that sing in the presence of mates" Archived 2008-12-26 at the Wayback Machine-Study of male mouse "song" with mouse song recording (MP3), by Washington University Medical School "It's just in mice! This scientist is calling out hype in science reporting". STAT. 2019-04-15. Arkive Photographs.Short text. High-Resolution Brain Maps and Brain Atlases of Mus musculus Further reading
This suggests FEN1 suppresses H-DNA-induced mutagenesis in a replication-dependent manner. H-DNA has been implicated in human cancer etiology because of the prevalence of H-DNA-forming sequences near translocation breakpoints in cancer genomes. Replication-mediated nuclease activity with H-DNA highlights another way H-DNA-induced mutagenesis and lead to cancer growth.
The skin (integument) is a composite organ, made up of at least two major layers of tissue: the epidermis and the dermis. The epidermis is the outermost layer, providing the initial barrier to the external environment. It is separated from the dermis by the basement membrane (basal lamina and reticular lamina). The epidermis contains melanocytes and gives color to the skin. The deepest layer of the epidermis also contains nerve endings. Beneath this, the dermis comprises two sections, the papillary and reticular layers, and contains connective tissues, blood vessels, glands, follicles, hair roots, sensory nerve endings, and muscular tissue. Between the integument and the deep body musculature there is a transitional subcutaneous zone made up of very loose connective and adipose tissue, the hypodermis. Substantial collagen bundles anchor the dermis to the hypodermis in a way that permits most areas of the skin to move freely over the deeper tissue layers.
=== Etymology === Obesity is from the Latin obesitas, which means "stout, fat, or plump". Ēsus is the past participle of edere (to eat), with ob (over) added to it. The Oxford English Dictionary documents its first usage in 1611 by Randle Cotgrave.
Photorespiration (also known as the oxidative photosynthetic carbon cycle or C2 cycle) refers to a process in plant metabolism where the enzyme RuBisCO oxygenates ribulose 1,5-bisphosphate (RuBP), wasting some of the energy produced by photosynthesis. The desired reaction is the addition of carbon dioxide to RuBP (carboxylation), a key step in the Calvin–Benson cycle, but approximately 25% of reactions by RuBisCO instead add oxygen to RuBP (oxygenation), creating a product that cannot be used within the Calvin–Benson cycle. This process lowers the efficiency of photosynthesis, potentially lowering photosynthetic output by 25% in C3 plants. Photorespiration involves a complex network of enzyme reactions that exchange metabolites between chloroplasts, leaf peroxisomes and mitochondria. The oxygenation reaction of RuBisCO is a wasteful process because 3-phosphoglycerate is created at a lower rate and higher metabolic cost compared with RuBP carboxylase activity. While photorespiratory carbon cycling results in the formation of G3P eventually, around 25% of carbon fixed by photorespiration is re-released as CO2 and nitrogen, as ammonia. Ammonia must then be detoxified at a substantial cost to the cell. Photorespiration also incurs a direct cost of one ATP and one NAD(P)H. While it is common to refer to the entire process as photorespiration, technically the term refers only to the metabolic network which acts to rescue the products of the oxygenation reaction (phosphoglycolate).
Sources: en.wikipedia.org
==== Crosslinking reactions ==== The Arion subfuscus mucus protein matrix contains heavily oxidized protein and thus, carries a substantial number of carbonyl groups that form cross-links and serve as the primary backbone of the gel. Direct metal-based cross-links formed by trace amounts of zinc and divalent ions like calcium and magnesium contribute to stabilizing the gel. The adhesive force derived by this protein matrix can be increased by the presence of metal ions in the bioadhesive. Copper and zinc treated Arion subfuscus mucus protein bioadhesives has shown evidence of increase in adhesion energy over the course of 72 hours due to a slower rate of loss of protein and carbohydrate components. To determine the adhesion energy (w), researchers used the following formula, taking the integral of the adhesive stress (σ) vs. strain (ε) curve and then multiplying it by the sample thickness (d).
== Further reading == Mishra, NK; Agarwal, S; Raghava, GP (July 2010). "Prediction of cytochrome P450 isoform responsible for metabolizing a drug molecule". BMC Pharmacology. 10: 8. doi:10.1186/1471-2210-10-8. PMC 2912882. PMID 20637097.
=== Interwar years (1919-1941) === Following the Ottoman Empire's post-World War I dismemberment and the foundation of the successor Turkish Republic in 1923, Mustafa Kemal Atatürk banned all Sufi orders and installed the Directorate of Religious Affairs as sole governing entity over religion. Bektashi lodges in Turkey were subsequently closed in 1925, with the order's leadership relocating to Albania and establishing its headquarters in Tirana. Salih Nijazi was the last Dedebaba in Turkey and the first in Albania, formerly appointed to his role in the latter country on 30 March 1930. The order became involved in Albanian politics, and some of its members, including Ismail Qemali, were major leaders of the Albanian National Awakening (Rilindja). After the lodges in Turkey were shut down, the order's headquarters moved to Albania. On 20 March 1930, Salih Nijazi was elected as the Dedebaba of the Bektashi community in Albania. Before Nijazi, the Dedebaba was Haxhi Fejzullah in Turkey. Njazi established the Bektashi World Headquarters in Tirana. Its construction was finished in 1941 during the Italian occupation of Albania. Nijazi promoted Bektashi Islam by introducing major ceremonies at popular tekkes. After he was murdered in 1941, Ali Riza succeeded him as the Dedebaba.
Officers had their own brothels under the chief of police (1888–1895), known sex connoisseur Nikolai Kleigels (Russian: Николай Клейгельс) who was selling young Polish girls dressed in exotic costumes for 10 roubles a visit. The girls were categorized by the Russian authorities as either inexpensive, medium-priced, or exclusive based on age, beauty and demeanour. In all cities with the Russian garrisons, army-licensed brothels were required to provide so-called "patriotic duty" to their regiments by giving one free visit per soldier, at least once a week. The battalions of 186 men each, divided into 9 companies, were taken to brothels under the command of an infantry sergeant. Each girl was required to service 20-21 members of a battalion, after which she would be allowed to take other men to make money in order to buy food. Jewish girls were especially vulnerable due to the totality of the tsarist official antisemitism including mass expulsions of Litvaks commanded by Alexander III of Russia which led to desperation and hunger. There was nonetheless growth in the national consciousness, and the Revolution in the Kingdom of Poland (1905–1907) resulted in the general improvement of the situation soon before the dissolution of the Empire. Some major political parties of the Second Polish Republic developed around that time in the Russian partition (ex. Polish Socialist Party). The New York Times noted some aspects of society that were still "risky" or "distressing" in 1907.
Sources: en.wikipedia.org
Reports describe modulation of GABA signalling, changes in monoamine turnover and effects on neurotrophic factor expression. These observations come mainly from animal and cell studies. A single unifying mechanism has not been demonstrated.
The peptide enters plasma rapidly and is broken down by ordinary proteases into amino acids and shorter fragments. Reported half-lives are short. Whether meaningful amounts of the intact molecule reach the brain is an open question.
Most clinical reports are small, published in Russian and not independently replicated. English-language reviews highlight the absence of large randomised trials. Conclusions about efficacy should be treated as provisional.
It is a seven-amino-acid peptide, Thr-Lys-Pro-Arg-Pro-Gly-Pro, produced by chemical synthesis rather than extracted from biological tissue. Its design is based on tuftsin, a natural immunomodulatory tetrapeptide. The C-terminal Pro-Gly-Pro segment is a common stabilising motif in short regulatory peptides.