Everything below concerns prothymosin alpha. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2025-10-10. Where a claim depends on a specific study, the study is described rather than over-claimed.
Biologically, the peptide is studied mainly in the context of immune cell development and regulation. It is produced in the thymus and in several other tissues, and it appears to influence the maturation and activity of T cells and other immune populations. Laboratory work describes effects on cytokine production, on the balance between T cell subsets, and on the function of dendritic cells. Much of this evidence comes from cell culture and animal models, so the extent to which the same pathways operate in humans remains an open question.
Clinical interest has centered on chronic viral hepatitis, on immune restoration in various conditions, and on use as an adjuvant intended to improve responses to vaccines. Trials have reported mixed results, and regulatory status differs sharply between countries; in some places it is a prescription product, while elsewhere it is sold without an approved therapeutic indication. Because published studies vary widely in design, population, and endpoints, comparisons across them are difficult and no single conclusion covers the whole literature.
Thymosin alpha-1 is a synthetic peptide of 28 amino acids whose sequence matches the amino-terminal region of prothymosin alpha. The chain is acetylated at its first residue and contains one disulfide bridge between two cysteine residues, which folds the molecule into a compact loop. Its molecular formula, C129H215N33O55, corresponds to a monoisotopic mass of roughly 3,106 daltons. Material used in laboratories is made by solid-phase synthesis rather than isolated from animal tissue.
Early work on thymic extracts in the 1960s described a heat-stable acidic fraction containing many polypeptides. Separation of that mixture yielded individual components, and thymosin alpha-1 was named as one of them on the basis of assays for T-cell activity. The first preparations came from calf thymus, while subsequent research and clinical material has been chemically synthesized. Nomenclature in older papers is inconsistent, and the same peptide sometimes appears under different designations, which complicates literature searches.
| Property | Value | Notes |
|---|---|---|
| Molecular mass | Approximately 3,108 Da | Consistent with a 28-residue acetylated peptide |
| Residue count | 28 | Corresponds to the amino terminal region of prothymosin alpha |
| Appearance of dry powder | White to off-white solid | Slight variation between lots is normal |
| Solubility class | Freely soluble in water | Low solubility in most organic solvents |
| Common synonyms | Thymosin alpha 1, T alpha 1 | The numeral reflects an early fraction numbering scheme |
Thymosin alpha 1 was identified in 1977 as a component of thymosin fraction 5, a heterogeneous preparation used in early studies of thymic function. Investigators purified the active material and determined its amino acid sequence, which enabled chemical synthesis. Work in the following decades concentrated on T-cell maturation and immune reconstitution in animals and small human cohorts. Early preparations varied in composition, so results from that period are difficult to compare with studies using defined synthetic peptide.
Clinical research has examined the peptide in chronic hepatitis B and C, as a vaccine adjuvant, and in sepsis and oncology settings. Findings across trials are mixed; some report changes in selected immune markers, while others find no clear clinical benefit. Many studies are small and define outcomes differently, which limits comparison. Regulatory approval is confined to a few countries, and the compound is not an approved drug in the United States or most of Europe.
Overall evidence quality varies considerably. A large share of published reports come from single centers, rely on surrogate immunological markers, or lack adequate control groups. Systematic reviews have highlighted this heterogeneity as a barrier to pooling results. Open questions include which patients, if any, might benefit, what treatment duration is appropriate, and whether any effect is independent of standard care. The peptide is often described as an immune modulator rather than a therapy for one disease, which complicates confirmatory trial design.
Whether the free 28-residue peptide circulates in human tissue remains debated. The best-documented human source is prothymosin alpha, a larger acidic protein that carries the sequence at its N-terminus. Reports of measurable peptide levels in serum and lymphoid tissue exist, yet some of that signal may come from cross-reacting fragments or from the parent protein. Most reviews therefore treat prothymosin alpha as the established human molecule and describe independent circulation of the small peptide as an unresolved question.
Immunological studies connect the peptide to multiple parts of the immune response. It has been reported to engage Toll-like receptor signaling, to promote dendritic cell maturation, and to influence the balance of T helper cell subsets. Changes in natural killer cell activity and in cytokine release appear in cell culture and animal models. These observations describe broad immunomodulatory behavior rather than a single defined receptor target, and the primary molecular interaction has not been settled.
Thymosin beta-4 is a separate 43-residue peptide that binds actin and participates in cell migration; it shares no sequence similarity with thymosin alpha-1 despite the common family name. Other preparative materials, such as thymosin fraction 5 and thymopoietin, contain distinct mixtures or peptides. The shared thymosin label reflects the tissue of origin used in early purification, not a common structural core. Treating these molecules as interchangeable is a frequent source of confusion in laboratory reports and in popular summaries alike.
Thymosin alpha-1 is a synthetic peptide of 28 amino acid residues that corresponds to a naturally occurring fragment first isolated from thymus tissue. Its chain is acetylated at the amino terminus, a modification that shields the peptide from rapid cleavage by aminopeptidases. The molecule carries a net negative charge at physiological pH and dissolves freely in water. Researchers classify it as an immune-modulating agent rather than a classical hormone, because it acts on several cell types of both the innate and the adaptive immune system.
The peptide was identified during work in the 1970s on thymosin fraction 5, a partially purified extract of calf thymus. Investigators separated that mixture and characterized individual components, one of which they named thymosin alpha-1. The same compound later received the international nonproprietary name thymalfasin. Commercial material is produced by solid-phase peptide synthesis rather than by extraction, so synthetic and natural forms share an identical sequence. Naming conventions vary across the literature, and readers should distinguish the alpha-1 peptide from other thymosins that have unrelated sequences and functions.
Brian David Strahl (born 1970) is an American biochemist and molecular biologist. He is currently a professor in the Department of Biochemistry & Biophysics at the University of North Carolina at Chapel Hill. Strahl is known for his research in the field of chromatin biology and histone modifications. Strahl, with C. David Allis proposed the “histone code hypothesis”.
Decreasing heroin purity, competition from increased access to prescription medications, and dissemination of "The Siegfried Method" (a relatively simple and cost-effective method of fentanyl production) were major factors in street suppliers' inclusion of fentanyl in their products. The current, fourth wave, which began in 2016, has been characterized by polysubstance overdose due to synthetic opioids like fentanyl mixed with stimulants such as methamphetamine or cocaine. In 2010, around 0.5% of opioid-related deaths were attributed to mixture with stimulants. This figure increased more than 50-fold by 2021, when about a third of opioid-related deaths, or 34,000, involved stimulant use. In 2017, the U.S. Department of Health and Human Services (HHS) announced a public health emergency due to an increase in the misuse of opioids. The administration introduced a strategic framework called the Five-Point Opioid Strategy, which includes providing access recovery services, increasing the availability of reversing agents for overdose, funding opioid misuse and pain research, changing treatments of people managing pain, and updating public health reports related to combating opioid drug misuse. Studies done in the U.S. from 2010 to 2019 revealed that about 86.6% of people in the U.S. who could have benefited from opioid use disorder treatment were not receiving it. Over the past decade, the uptake of medications for opioid use disorder has increased, but there are still many regions with a prevalence of opioid use disorder and lack of medical support. The U.S.
== Mechanism of action == Gallium (68Ga) gozetotide binds with prostate-specific membrane antigen (PSMA). This binds to cells that express PSMA, including malignant prostate cancer cells. The radioactive isotope of gallium, 68Ga is responsible for emitting β+ radiations and X-rays. This helps in recording images by positron emission tomography (PET) and CT scan.
Sources: en.wikipedia.org
== MrBayes software == MrBayes is a free software tool that performs Bayesian inference of phylogeny. It was originally written by John P. Huelsenbeck and Frederik Ronquist in 2001. As Bayesian methods increased in popularity, MrBayes became one of the software of choice for many molecular phylogeneticists. It is offered for Macintosh, Windows, and UNIX operating systems and it has a command-line interface. The program uses the standard MCMC algorithm as well as the Metropolis coupled MCMC variant. MrBayes reads aligned matrices of sequences (DNA or amino acids) in the standard NEXUS format. MrBayes uses MCMC to approximate the posterior probabilities of trees. The user can change assumptions of the substitution model, priors and the details of the MC³ analysis. It also allows the user to remove and add taxa and characters to the analysis. The program includes, among several nucleotide models, the most standard model of DNA substitution, the 4x4 also called JC69, which assumes that changes across nucleotides occur with equal probability. It also implements a number of 20x20 models of amino acid substitution, and codon models of DNA substitution. It offers different methods for relaxing the assumption of equal substitutions rates across nucleotide sites. MrBayes is also able to infer ancestral states accommodating uncertainty to the phylogenetic tree and model parameters. MrBayes 3 was a completely reorganized and restructured version of the original MrBayes. The main novelty was the ability of the software to accommodate heterogeneity of data sets.
==== Drugs ==== The ability to maintain functional telomeres may be one mechanism that allows cancer cells to grow in vitro for decades. Telomerase activity is necessary to preserve many cancer types and is inactive in somatic cells, creating the possibility that telomerase inhibition could selectively repress cancer cell growth with minimal side effects. If a drug can inhibit telomerase in cancer cells, the telomeres of successive generations will progressively shorten, limiting tumor growth. Telomerase is a good biomarker for cancer detection because about 85% of human cancer cells express high levels of it. Telomerase activity can be identified by its catalytic protein domain (hTERT). hTERT is believed to be the rate-limiting step in telomerase activity, and as a consequence, increased hTERT expression is associated with elevated telomerase activity in many cancer types. Various cancer cells and fibroblasts transformed with hTERT cDNA have high telomerase activity, while somatic cells do not. Cells testing positive for hTERT have positive nuclear signals. Epithelial stem cell tissue and its early daughter cells are the only noncancerous cells in which hTERT can be detected. Since hTERT expression is dependent only on the number of tumor cells within a sample, the amount of hTERT indicates the severity of cancer. The expression of hTERT can also be used to distinguish benign tumors from malignant tumors. Malignant tumors have higher hTERT expression than benign tumors.
Parental care came about independently in: mammals, most birds, some insects, some fish and crocodilians. Regeneration, many different unrelated species can grow new limbs, tail or other body parts, if body parts are lost. The statocyst is a balance sensory receptor independently found in different organisms like: some aquatic invertebrates, including bivalves, cnidarians, echinoderms, cephalopods, and crustaceans. Also found in single-cell ciliate. A similar structure is also found in Xenoturbella. Hearing came about in many different unrelated species with the: tympanal organ, Johnston's organ and mammal/bird ears. Also the simpler hearing found in reptiles, with only the stapes bone. Pincushion-form starfish have evolved at least four times. Infrared vision is in many different unrelated species: pit viper snakes (rattlesnakes), pythons, vampire bats, and wood-boring wasps and fire beetles.
Sources: en.wikipedia.org
This all-or-nothing property of the action potential sets it apart from graded potentials such as receptor potentials, electrotonic potentials, subthreshold membrane potential oscillations, and synaptic potentials, which scale with the magnitude of the stimulus. A variety of action potential types exist in many cell types and cell compartments as determined by the types of voltage-gated channels, leak channels, channel distributions, ionic concentrations, membrane capacitance, temperature, and other factors. The principal ions involved in an action potential are sodium and potassium cations; sodium ions enter the cell, and potassium ions leave, restoring equilibrium. Relatively few ions need to cross the membrane for the membrane voltage to change drastically. The ions exchanged during an action potential, therefore, make a negligible change in the interior and exterior ionic concentrations. The few ions that do cross are pumped out again by the continuous action of the sodium–potassium pump, which, with other ion transporters, maintains the normal ratio of ion concentrations across the membrane. Calcium cations and chloride anions are involved in a few types of action potentials, such as the cardiac action potential and the action potential in the single-cell alga Acetabularia, respectively. Although action potentials are generated locally on patches of excitable membrane, the resulting currents can trigger action potentials on neighboring stretches of membrane, precipitating a domino-like propagation.
While some early bird-like species may have already been arboreal as well (including dromaeosaurids) such as Microraptor) most non-avialan dinosaurs seem to have relied on land-based locomotion. A good understanding of how dinosaurs moved on the ground is key to models of dinosaur behavior; the science of biomechanics, pioneered by Robert McNeill Alexander, has provided significant insight in this area. For example, studies of the forces exerted by muscles and gravity on dinosaurs' skeletal structure have investigated how fast dinosaurs could run, whether diplodocids could create sonic booms via whip-like tail snapping, and whether sauropods could float.
=== Early life: 1946–1966 === Bantu Stephen Biko was born on 18 December 1946, at his grandmother's house in Tarkastad, Cape Province (now the Eastern Cape). The third child of Mzingaye Mathew Biko and Alice 'Mamcete' Biko, he had an older sister, Bukelwa, an older brother, Khaya, and a younger sister, Nobandile. His parents had married in Whittlesea, where his father worked as a police officer. Mzingaye was transferred to Queenstown, Port Elizabeth, Fort Cox, and finally King William's Town, where he and Alice settled in Ginsberg township. This was a settlement of around 800 families, with every four families sharing a water supply and toilet. Both Africans and Coloured people lived in the township, where Xhosa, Afrikaans, and English were all spoken. After resigning from the police force, Mzingaye worked as a clerk in the King William's Town Native Affairs Office, while studying for a law degree by correspondence from the University of South Africa. Alice was employed first in domestic work for local white households, then as a cook at Grey Hospital in King William's Town. According to his sister, it was this observation of his mother's difficult working conditions that resulted in Biko's earliest politicisation.
Relamorelin (INN, USAN) (developmental code names RM-131, BIM-28131, BIM-28163) is a synthetic peptide, centrally penetrant, selective agonist of the ghrelin/growth hormone secretagogue receptor (GHSR) which is under development by Allergan pharmaceuticals for the treatment of diabetic gastroparesis, chronic idiopathic constipation, and anorexia nervosa. It is a pentapeptide and an analogue of ghrelin with improved potency and pharmacokinetics. In humans, relamorelin produces increases in plasma growth hormone, prolactin, and cortisol levels, and, like other GHSR agonists, increases appetite. As of June 2015, relamorelin is in phase II clinical trials for diabetic gastroparesis and constipation. The United States Food and Drug Administration (FDA) has granted Fast Track designation to relamorelin for diabetic gastroparesis. The development of the drug is uncertain as the most recent mention of it was in a 2019 SEC filing from the drug manufacturer lists the drug's expected launch year as 2024, but not in subsequent filings or press releases.
Sources: en.wikipedia.org
The name reflects an early convention for naming thymus-derived fractions. The peptide is characterized and measured as a defined molecule, and it does not operate through a single classical endocrine axis.
Its sequence corresponds to the amino-terminal portion of prothymosin alpha, a larger protein present in many cell types. The isolated 28-residue peptide is a fragment of that protein rather than a separately encoded molecule, and laboratory material is produced by synthesis.
The single bridge between two cysteine residues holds the chain in a folded loop that influences its shape and its behavior in solution. Loss of the bridge through reduction or oxidation shifts chromatographic retention and is tracked during stability work.
It is a defined 28-residue sequence derived from a larger precursor, whereas many other thymic preparations are mixtures of several polypeptides. Its acetylated amino terminus and single disulfide bridge distinguish it chemically from unrelated thymic extracts.