Everything below concerns heptapeptide. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-02-19. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C33H57N11O9 | Free peptide form |
| Molecular mass | About 751.9 Da | Calculated average mass |
| Amino acid sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Single-letter form TKPRPGP |
| Structural basis | Tuftsin analogue | Extended version of a natural tetrapeptide |
| Development origin | Russian Academy of Sciences | Work carried out from the 1980s onward |
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.
Quantification in biological matrices relies on liquid chromatography coupled to tandem mass spectrometry with stable-isotope internal standards. Low plasma concentrations and adsorption to container surfaces both complicate measurement. Solid-phase extraction is often needed to reduce matrix interference before injection. Reported limits of quantification differ widely between laboratories, which makes direct comparison of pharmacokinetic results difficult and limits meta-analysis.
Peptide bonds are vulnerable to protease attack, and Selank is no exception. Measured half-life in serum is short, on the order of minutes in several reports, which explains why intranasal administration is the common route described in the literature. Absorption across the nasal mucosa partially bypasses first-pass hepatic metabolism. Quantitative data on human bioavailability remain limited and are difficult to compare across studies.
Reversed-phase high-performance liquid chromatography is the standard technique for estimating peptide purity. The result is a peak-area percentage, which describes how much of the detected material elutes as the main peak in one run. Mass spectrometry confirms the molecular mass and can reveal truncated, adducted, or otherwise modified species. Amino acid analysis or tandem mass spectrometry can address sequence fidelity when identity is in doubt. None of these measurements, taken alone, establishes that a sample is fit for any specific purpose.
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.
Hunkapiller's idea would require competing against his own customers, to all of whom Applied Biosystems sold its sequencing machines and their chemical reagents. However, he calculated that it would also mean doubling the market for that equipment. Hunkapiller brought in Dr. J. Craig Venter to direct the project. Tony White, president of the Perkin-Elmer Corporation backed Hunkapiller on the venture. They organized the new company to accomplish the task. In May 1998, Celera Genomics was formed, to rapidly accelerate the human DNA sequencing process. Dr. Venter boldly declared to the media that he would complete the genome decoding by 2001. That bold announcement prompted the academic consortium to accelerate their own deadline by a couple years, to 2003. Also in 1998, PE Biosystems partnered with Hitachi, Ltd. to develop electrophoresis-based genetic analysis systems, which resulted in their chief new genomics instrument, the ABI PRISM 3700 DNA Analyzer, which advanced the Human Genome sequencing project by nearly five years ahead of schedule. The partnerships sold hundreds of the 3700 analyzers to Celera, and also to others worldwide. The new machine cost US$300,000 each, but was a major leap beyond its predecessor, the 377, and was fully automated, allowing genetic decoding to run around the clock with little supervision. According to Venter, the machine was so revolutionary that it could decode in a single day the same amount of genetic material that most DNA labs could produce in a year.
=== Legal status === Icatibant received orphan drug status in Australia, the EU, Switzerland, and the US for the treatment of hereditary angioedema (HAE). In the EU, the approval by the European Commission (July 2008) allows Jerini to market Firazyr in the European Union's 27 member states, as well as Switzerland, Liechtenstein and Iceland, making it the first product to be approved in all EU countries for the treatment of hereditary angioedema. In the US, the drug was granted FDA approval in August 2011.
== Supplementation == α-Ketoglutaric acid is naturally generated and consumed via the citric acid cycle. Nevertheless, studies that are primarily preclinical (i.e., conducted in animal models of disease or on animal or human tissues) have examined the effects of adding this molecule to biological systems in amounts beyond what is naturally present. Middle‐aged, i.e., 10‐month‐old, mice had lower serum levels of α-ketoglutarate than 2‐month‐old mice. Oral supplementation restores blood levels of α-ketoglutarate in these mice.
1993/3173) Education (Individual Pupils' Achievements) (Information) Regulations 1993 (S.I. 1993/3182) Education (European Economic Area) (Amendment) Regulations 1993 (S.I. 1993/3183) Education (European Economic Area) (Scotland) Regulations 1993 (S.I. 1993/3184) Liquor Licensing (Fees) (Scotland) Order 1993 (S.I. 1993/3185) Advice and Assistance (Assistance by Way of Representation) (Scotland) Amendment (No. 2) Regulations 1993 (S.I. 1993/3186) Advice and Assistance (Financial Limit) (Scotland) Regulations 1993 (S.I. 1993/3187) Education (Grant–maintained Schools) (Initial Sponsor Governors) Regulations 1993 (S.I. 1993/3188) Education (Acquisition of Grant-maintained Status) (Ballot Information) Regulations 1993 (S.I. 1993/3189) Supreme Court Fees (Amendment) Order 1993 (S.I. 1993/3191) Cod and Saithe (Specified Sea Areas) (Prohibition of Fishing) Order 1993 (S.I. 1993/3192) Haddock, Hake, Nephrops, Plaice and Sole (Specified Sea Areas) (Prohibition of Fishing) Order 1993 (S.I. 1993/3193) Social Security (Severe Disablement Allowance) Amendment Regulations 1993 (S.I. 1993/3194) Doncaster Borough Council (North Bridge Relief Road) (Crossing of Navigable Waterway (Sheffield and South Yorkshire Navigation River Don New Cut)) Scheme 1991 Confirmation Instrument 1993 (S.I. 1993/3195) Education (Distribution by Schools of Information about Further Education Institutions) (England) Regulations 1993 (S.I. 1993/3197) Nitrate Sensitive Areas (Designation) (Amendment) Order 1993 (S.I. 1993/3198) Broadcasting (Restrictions on the Holding of Licences) (Amendment) Order 1993 (S.I.
The chemosynthetic bacteria grow into a thick mat which attracts other organisms, such as amphipods and copepods, which graze upon the bacteria directly. Larger organisms, such as snails, shrimp, crabs, tube worms, fish (especially eelpout, cutthroat eel, Ophidiiformes and Symphurus thermophilus), and octopuses (notably Vulcanoctopus hydrothermalis), form a food chain of predator and prey relationships above the primary consumers. The main families of organisms found around seafloor vents are annelids, gastropods, and crustaceans, with large bivalves, vestimentiferan worms, and "eyeless" shrimp making up the bulk of nonmicrobial organisms.
Sources: en.wikipedia.org
Z-DNA binding protein 1, also known as Zuotin, is a Saccharomyces cerevisiae yeast gene. Zuo1 has been identified in vitro as a tRNA and Z-DNA binding protein. The name "zuotin" is derived from the Chinese word "zuo" meaning "left". It is a member of Hsp40 family. Like all other Hsp40 members it also contains a classic J domain. In 1990, Shuguang Zhang of MIT made a serendipitous discovery of a self-assembling peptide in yeast protein Zuotin. This discovery led to the development of a new field of peptide nanobiotechnology and to designs of a variety of self-assembling peptides for widespread uses, including peptide hydrogels in materials science, 3D tissue cell culture and tissue engineering, nanomedicine, sustained molecular releases, clinical and surgical applications. Zuotin and related proteins contain a unique Zuotin homology domain (ZHD). It associates with the Hsp70 family Ssz1 to form a ribosome associated complex (RAC). In such a complex, the N-terminal domains (including the J domain) associates with Ssz1p on the surface of the large (60S) ribosomal subunit. ZHD provides further contacts with the 60S subunit and connects to a subunit-spanning medium domain (MD), the "neck" of RAC. The four-helix-bundle RAC head domain is located at the C-terminus and binds the small (40S) subunit. The J domain-Ssz1p complex, located over the peptide exit tunnel of the large ribosomal subunit, helps the nascent peptide fold.
Erasistratus was also responsible for naming and describing the function of the epiglottis and the heart's valves, including the tricuspid. During the third century, Greek physicians were able to differentiate nerves from blood vessels and tendons and to realize that the nerves convey neural impulses. It was Herophilus who made the point that damage to motor nerves induced paralysis. Herophilus named the meninges and ventricles in the brain, appreciated the division between cerebellum and cerebrum and recognized that the brain was the "seat of intellect" and not a "cooling chamber" as propounded by Aristotle. Herophilus is also credited with describing the optic, oculomotor, motor division of the trigeminal, facial, vestibulocochlear and hypoglossal nerves. Incredible feats were made during the third century BCE in both the digestive and reproductive systems. Herophilus discovered and described not only the salivary glands but also the small intestine and liver. He showed that the uterus is a hollow organ and described the ovaries and uterine tubes. He recognized that spermatozoa were produced by the testes and was the first to identify the prostate gland. The anatomy of the muscles and skeleton is described in the Hippocratic Corpus, an Ancient Greek medical work written by unknown authors. Aristotle described vertebrate anatomy based on animal dissection. Praxagoras identified the difference between arteries and veins.
American chemist and psychopharmacologist Alexander Shulgin reported he synthesized MDMA in 1965 while researching methylenedioxy compounds at Dow Chemical Company, but did not test the psychoactivity of the compound at this time. Around 1970, Shulgin sent instructions for N-methylated MDA (MDMA) synthesis to the founder of a Los Angeles chemical company who had requested them. This individual later provided these instructions to a client in the Midwest. Shulgin may have suspected he played a role in the emergence of MDMA in Chicago. Shulgin first heard of the psychoactive effects of N-methylated MDA around 1975 from a young student who reported "amphetamine-like content". Around 30 May 1976, Shulgin again heard about the effects of N-methylated MDA, this time from a graduate student in a medicinal chemistry group he advised at San Francisco State University who directed him to the University of Michigan study. She and two close friends had consumed 100 mg of MDMA and reported positive emotional experiences. Following the self-trials of a colleague at the University of San Francisco, Shulgin synthesized MDMA and tried it himself in September and October 1976. Shulgin and David E. Nichols first reported on MDMA and its psychoactive effects in humans in a presentation at a conference in Bethesda, Maryland in December 1976. This conference paper was subsequently formally published in 1978.
== Reverse vaccinology with Meningococcus B == Attempts at reverse vaccinology first began with Meningococcus B (MenB). Meningococcus B caused over 50% of meningococcal meningitis, and scientists had been unable to create a successful vaccine for the pathogen because of the bacterium's unique structure. This bacterium's polysaccharide shell is identical to that of a human self-antigen, but its surface proteins vary greatly; and the lack of information about the surface proteins caused developing a vaccine to be extremely difficult. As a result, Rino Rappuoli and other scientists turned towards bioinformatics to design a functional vaccine. Rappuoli and others at the J. Craig Venter Institute first sequenced the MenB genome. Then, they scanned the sequenced genome for potential antigens. They found over 600 possible antigens, which were tested by expression in Escherichia coli. The most universally applicable antigens were used in the prototype vaccines. Several proved to function successfully in mice, however, these proteins alone did not effectively interact with the human immune system due to not inducing a good immune response in order for the protection to be achieved. Later, by addition of outer membrane vesicles that contain lipopolysaccharides from the purification of blebs on gram negative cultures. The addition of this adjuvant (previously identified by using conventional vaccinology approaches) enhanced immune response to the level that was required. Later, the vaccine was proven to be safe and effective in adult humans.
Sources: en.wikipedia.org
== External links == MedlinePlus drug information - Aminoglycosides (Systemic) Science Daily Bacterial 'Battle for Survival' - Rhodostreptomycin Wikiversity page for the International Ototoxicity Management Group
==== Other health effects ==== Breastfeeding may reduce the risk of necrotizing enterocolitis (NEC) in premature babies. Breastfeeding or introduction of gluten while breastfeeding does not protect against celiac disease among at-risk children. Breast milk of healthy human mothers who eat gluten-containing foods presents high levels of non-degraded gliadin (the main gluten protein). Early introduction of traces of gluten in babies to potentially induce tolerance does not reduce the risk of developing celiac disease. Delaying the introduction of gluten does not prevent, but is associated with a delayed onset of the disease. About 14 to 19 percent of leukemia cases may be prevented by breastfeeding for six months or longer. However, breastfeeding is also the primary cause of adult T-cell leukemia/lymphoma, as the HTLV-1 virus is transmitted through breastmilk. Breastfeeding is associated with a lower chance of developing diabetes mellitus type 1 in the offspring. Breastfed babies also appear to have a lower likelihood of developing diabetes mellitus type 2 later in life. Breastfeeding may decrease the risk of cardiovascular disease in later life, as indicated by lower cholesterol and C-reactive protein levels in breastfed adult women. Breastfed infants have somewhat lower blood pressure later in life, but it is unclear how much practical benefit this provides. A 1998 study suggested that breastfed babies have a better chance of good dental health than formula-fed infants because of the developmental effects of breastfeeding on the oral cavity and airway.
=== Psychological support === Psychological support, often in the form of cognitive-behavioral therapy (CBT), family-based treatment, or psychotherapy aims to change distorted thoughts and behaviors around food, body image, and self-worth, with family-based therapy also being a key approach for younger patients.
=== Mycorrhizal associations === Boletus edulis is mycorrhizal—it is in a mutualistic relationship with the roots of plants (hosts), in which the fungus exchanges nitrogen and other nutrients extracted from the environment for fixed carbon from the host. Other benefits for the plant are evident: in the case of the Chinese chestnut, the formation of mycorrhizae with B. edulis increases the ability of plant seedlings to resist water stress, and increases leaf succulence, leaf area, and water-holding ability. The fungus forms a sheath of tissue around terminal, nutrient-absorbing root tips, often inducing a high degree of branching in the tips of the host, and penetrating into the root tissue, forming, to some mycologists, the defining feature of ectomycorrhizal relationships, a hartig net. The ectomycorrhizal fungi are then able to exchange nutrients with the plant, effectively expanding the root system of the host plant to the furthest reaches of the symbiont fungi. Compatible hosts may belong to multiple families of vascular plants that are widely distributed throughout the Northern Hemisphere; according to one 1995 estimate, there are at least 30 host plant species distributed over more than 15 genera. Examples of mycorrhizal associates include Chinese red pine, Mexican weeping pine, Scots pine, Norway spruce, Coast Douglas-fir, mountain pine, and Virginia pine. The fungus has also been shown to associate with gum rockrose, a pioneer early stage shrub that is adapted for growth in degraded areas, such as burned forests.
Respiratory burst (or oxidative burst) is the rapid release of the reactive oxygen species (ROS), superoxide anion (O−2) and hydrogen peroxide (H2O2), from different cell types. This is usually utilised for mammalian immunological defence, but also plays a role in cell signalling. The respiratory burst is also implicated in the ovum of animals following fertilization. It may also occur in plant cells.
Sources: en.wikipedia.org
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.
The core four residues correspond to tuftsin, which occurs naturally as part of immunoglobulin G. The full seven-residue sequence, however, is not a known endogenous peptide. It is a laboratory-designed analogue intended to combine tuftsin-like activity with greater resistance to breakdown.
No single receptor has been confirmed as the primary target. Reports describe involvement of the GABAergic system, interference with enkephalin degradation, and shifts in neurotrophic factor expression. Because these observations come from different models and assays, they have not yet been integrated into one accepted mechanism.
Selank is a synthetic heptapeptide designed as a stabilized analog of the natural tetrapeptide tuftsin. It has been investigated mainly for anxiolytic and cognitive effects. It is not an approved pharmaceutical in most countries.