Everything below concerns synthetic peptide. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-03-04. Where a claim depends on a specific study, the study is described rather than over-claimed.
The molecule consists of 28 amino acid residues with an acetyl group attached to the N-terminal serine. Its sequence is acidic overall, with several glutamic and aspartic acid residues distributed along the chain and no cysteine, so disulfide bridges do not form. The peptide carries a net negative charge at physiological pH. Because the N-terminus is blocked, the intact molecule resists degradation by many aminopeptidases, which contributes to its stability in biological fluids.
The peptide is generated in cells by cleavage of prothymosin alpha, a larger acidic protein encoded by the PTMA gene. Prothymosin alpha is expressed in many tissues, not only in the thymus, and its functions include nuclear roles in chromatin-related processes. The 28-residue fragment corresponds to the N-terminal portion of that precursor. How the cleavage occurs and how the fragment's concentration is regulated remain open questions; circulating amounts are small and difficult to measure reliably with routine assays.
Most published studies on thymosin alpha-1 report changes in immune measurements rather than clinical outcomes, and findings differ across designs and populations. Whether the peptide signals through one defined receptor or through several less specific interactions remains an open question. Its reported circulation half-life of a few hours complicates comparison of dosing schedules across trials. Mechanistic claims are frequently drawn from isolated cell cultures, and how far those results extend to whole organisms is unresolved.
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 |
|---|---|---|
| Chemical class | Acetylated peptide | N-terminal acetyl group blocks aminopeptidase attack |
| Residue count | 28 amino acids | Matches the N-terminus of prothymosin alpha |
| Molecular mass | About 3,108 Da | Value for the free, unmodified peptide |
| Isoelectric point | Approximately 4.2 | Acidic; net negative charge at neutral pH |
| Encoding gene | PTMA | Human gene for the precursor protein |
Immune signaling studies link thymosin alpha 1 to Toll-like receptor pathways, particularly TLR2 and TLR9, on dendritic cells and other antigen-presenting cells. Activation of these receptors promotes maturation of T cells and increases natural killer cell activity. The peptide shifts cytokine output toward a T helper 1 profile, raising interferon gamma and interleukin 2 while modulating interleukin 10. Whether these effects translate into clinical benefit for any specific disease remains a subject of debate. Reported outcomes vary across trials and populations.
Thymosin alpha 1 is approved as a medicine in several countries, including Italy and China, for indications such as chronic hepatitis B and as an immune adjuvant. It is not approved by the United States Food and Drug Administration as a therapeutic product. In research settings the peptide appears in studies of sepsis, vaccine response, and oncology support, often with mixed or inconclusive results. The evidence base is uneven, and reviews note that many trials were small. Regulatory status therefore differs widely between jurisdictions.
Thymosin alpha 1 is a short peptide of 28 amino acid residues that derives from the amino terminal region of a larger precursor protein known as prothymosin alpha. The peptide carries an acetyl group on its first residue and contains no disulfide bonds or carbohydrate chains. Its sequence is highly conserved across mammalian species, which is one reason laboratories treat it as a molecule with a defined and reproducible structure rather than a variable tissue extract. The name follows an early naming convention for thymus-derived fractions and does not imply that the peptide acts as a hormone in the classical endocrine sense.
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.
Histology image: 09601loa – Histology Learning System at Boston University – "Digestive System: Oral Cavity and Teeth – lip, oral mucosa" Histology image: 95_04 at the University of Oklahoma Health Sciences Center – "Lip" Histology image: 95_07 at the University of Oklahoma Health Sciences Center – "Lip" Common Dental and Oral Mucosal Disorders, Duke University at https://web.archive.org/web/20160303221658/http://pamodules.mc.duke.edu/Oral_Health/Print.asp?CourseNum=1&LessonNum=3
Rates of MI for a given age have decreased globally between 1990 and 2010. In 2011, an MI was one of the top five most expensive conditions during inpatient hospitalizations in the US, with a cost of about $11.5 billion for 612,000 hospital stays.
=== Novel technologies and mechanisms of cognitive function === Technologies for imaging brain activity The Sur laboratory developed high resolution two-photon microscopy in the intact mouse brain to show that synapses on visual cortex pyramidal neurons are highly dynamic structures whose form and function can change under the influence of electrical activity. They have continued to develop advanced multi-photon technologies for imaging the calcium activity of cells and their processes across multiple cortical areas and depths. Mechanisms of learning and cognition Combined with cell- and projection-specific manipulations, high-density recordings and computational analyses, these technologies have demonstrated principles of information representation, decisions and action selection in higher (parietal and prefrontal) cortex in mice performing perceptual discrimination and memory-guided decision tasks. The lab has elucidated distinct roles of prefrontal cortex subregions that provide feedback to V1 across behavioral states, demonstrating exquisite specificity of top-down projections in cortical networks. The lab is opening up new ways to address longstanding questions about the neural architecture of cognition. For example, they have shown that pulvinar inputs to prefrontal cortex encode sensory history as a low-dimensional activity manifold that forms a substrate for attention, and modular subsets of prefrontal cortex neurons representing specific functions are computationally recombined across tasks to generate flexible behavior.
== Function == Msr is ubiquitous and highly conserved. Human and animal studies have shown the highest levels of expression in kidney and liver. It carries out the enzymatic reduction of methionine sulfoxide (MetO), the oxidized form of the amino acid methionine (Met), back to methionine, using thioredoxin to catalyze the enzymatic reduction and repair of oxidized methionine residues. Its proposed function is thus the repair of oxidative damage to proteins to restore biological activity. Oxidation of methionine residues in tissue proteins can cause them to misfold or otherwise render them dysfunctional.
== Chemistry == Pseudoephedrine, also known structurally as (1S,2S)-α,N-dimethyl-β-hydroxyphenethylamine or as (1S,2S)-N-methyl-β-hydroxyamphetamine, is a substituted phenethylamine, amphetamine, and β-hydroxyamphetamine derivative. It is a diastereomer of ephedrine. Pseudoephedrine is a small-molecule compound with the molecular formula C10H15NO and a molecular weight of 165.23 g/mol. It has an experimental log P of 0.89, while its predicted log P values range from 0.9 to 1.32. The compound is relatively lipophilic, but is also more hydrophilic than other amphetamines. The lipophilicity of amphetamines is closely related to their brain permeability. For comparison to pseudoephedrine, the experimental log P of methamphetamine is 2.1, of amphetamine is 1.8, of ephedrine is 1.1, of phenylpropanolamine is 0.7, of phenylephrine is -0.3, and of norepinephrine is -1.2. Methamphetamine has high brain permeability, whereas phenylephrine and norepinephrine are peripherally selective drugs. The optimal log P for brain permeation and central activity is about 2.1 (range 1.5–2.7). Pseudoephedrine is readily reduced into methamphetamine or oxidized into methcathinone.
Sources: en.wikipedia.org
Polonium has few applications, and those are related to its radioactivity: heaters in space probes, antistatic devices, sources of neutrons and alpha particles, and poison (e.g., poisoning of Alexander Litvinenko). It is extremely dangerous to humans.
1900 marked the so-called rediscovery of Mendel by Carl Correns, who arrived at Mendel's laws (which were not actually present in Mendel's work). Soon after, cytologists (cell biologists) proposed that chromosomes were the hereditary material. This was taken up by Carl Correns and others between 1910 and 1915 as the "Mendelian-chromosome theory" of heredity. Thomas Hunt Morgan and the "Drosophilists" in his fly lab applied this to a new model organism. They hypothesized crossing over to explain linkage and constructed genetic maps of the fruit fly Drosophila melanogaster, which became a widely used model organism. Hugo de Vries tried to link the new genetics with evolution; building on his work with heredity and hybridization, he proposed a theory of mutationism, which was widely accepted in the early 20th century. Lamarckism, or the theory of inheritance of acquired characteristics also had many adherents. Darwinism was seen as incompatible with the continuously variable traits studied by biometricians, which seemed only partially heritable. In the 1920s and 1930s—following the acceptance of the Mendelian-chromosome theory— the emergence of the discipline of population genetics, with the work of R.A. Fisher, J.B.S. Haldane and Sewall Wright, unified the idea of evolution by natural selection with Mendelian genetics, producing the modern synthesis. The inheritance of acquired characters was rejected, while mutationism gave way as genetic theories matured.
Amino acid dating is a dating technique used to estimate the age of a specimen in paleobiology, archaeology, forensic science, taphonomy, sedimentary geology and other fields. This technique relates changes in amino acid molecules to the time elapsed since they were formed. All biological tissues contain amino acids. All amino acids except glycine (the simplest one) are optically active, having an asymmetric carbon atom. This means that the amino acid can have two different configurations, "D" or "L" which are mirror images of each other. With a few important exceptions, living organisms keep all their amino acids in the "L" configuration. When an organism dies, control over the configuration of the amino acids ceases, and the ratio of D to L moves from a value near 0 towards an equilibrium value near 1, a process called racemization. Thus, measuring the ratio of D to L in a sample enables one to estimate how long ago the specimen died.
Afropop Worldwide's public radio program on Zulu Music, "The Zulu Factor" People of Africa, Zulu marriage explained An article on Piet Retief, including his interactions with Dingane History section of the official page for the Zululand region Archived 26 September 2008 at the Wayback Machine Human Rights Watch report on KwaZulu, just before the 1994 elections – This includes detailed, well-referenced, sections on recent Zulu history.
Sources: en.wikipedia.org
== Taxonomy == The death cap is named in Latin as such in the correspondence between the English physician Thomas Browne and Christopher Merrett. It was described by French botanist Sébastien Vaillant in 1727, who gave a succinct phrase name "Fungus phalloides, annulatus, sordide virescens, et patulus" (a phallus-shaped, ring-stemmed, dirty green mushroom with a large 'spreading' cap). In 1821, Elias Magnus Fries described it as Agaricus phalloides, but included all white amanitas within its description. Finally, in 1833, Johann Heinrich Friedrich Link settled on the name Amanita phalloides, after Persoon had named it Amanita viridis 30 years earlier. Although Louis Secretan's use of the name A. phalloides predates Link's, it has been rejected for nomenclatural purposes because Secretan's works did not use binomial nomenclature consistently; some taxonomists have, however, disagreed with this opinion. Amanita phalloides is the type species of Amanita section Phalloideae, a group that contains all of the deadly poisonous Amanita species thus far identified. Most notable of these are the species known as destroying angels, including A. virosa, A. bisporigera, A. ocreata, A. verna, and more than a dozen others. The term "destroying angel" has been applied to A. phalloides at times, but "death cap" is by far the most common vernacular name used in English. Other common names also listed include "stinking amanita" and "deadly amanita". A rarely appearing, all-white form was initially described A. phalloides f. alba by Max Britzelmayr, though its status has been unclear.
Real advancement came in the early 1800s, when Linnaeus's student Erik Acharius—later hailed as the "father of lichenology"—re-examined the group. From 1798 to 1814, Acharius published four influential monographs that divided Lichen into numerous genera and sketched a finer hierarchy: Lichenographiae Suecicae Prodromus (1798), Methodus (1803), Lichenographia Universalis (1810), and Synopsis Methodica Lichenum (1814). Beyond cataloguing hundreds of species, he introduced microscopic characters—such as the structure of the spore-producing bodies (apothecia)—as classificatory tools. His anatomical focus freed lichenology from its old dependence on thallus form (crustose, foliose, fruticose) and laid the groundwork for a multi-character "natural" system. During the early–mid 1800s, lichen taxonomists steadily wove fresh microscopic insights into their work. With compound microscopes common by the 1830s, researchers saw that lichens contain distinct internal layers and reproductive organs. A cadre of European "microscope taxonomists"—Antoine Fée, Giuseppe De Notaris, Vittore Trevisan, Camille Montagne, Ernst Stizenberger and Edward Tuckerman—used those details to delimit genera on ascospore shape, septation and exciple anatomy, giving lichenology its first genuinely anatomical classification. Meanwhile, William Nylander drew on micro‑anatomy to craft a far richer hierarchical scheme, describing hundreds of new taxa yet largely ignoring spore data.
Ansuvimab was developed by the Vaccine Research Center with support of the United States National Institutes of Health and the Defense Advanced Projects Agency. The heavy and light chain sequences of ansuvimab mAb were cloned into CHO cell lines to enable large-scale production of antibody product for use in humans. In early 2018, a Phase 1 clinical trial of ansuvimab's safety, tolerability and pharmacokinetics was conducted by Dr. Martin Gaudinski within the Vaccine Research Center Clinical Trials Program that is led by Dr. Julie E. Ledgerwood. The study was performed in the United States at the NIH Clinical Center and tested single dose infusions of ansuvimab infused over 30 minutes. The study showed that ansuvimab was safe, had minimal side effects and had a half-life of 24 days. A license for ansuvimab was obtained by Ridgeback Biotherapeutics in 2018, from the National Institutes of Health-National Institute of Allergy and Infectious Diseases. Ansuvimab was given orphan drug status in May 2019 and March 2020.
Sources: en.wikipedia.org
Thymosin fraction 5 is a mixture of many peptides obtained from thymus tissue, while thymosin alpha 1 is a single defined 28-residue molecule. The two names appear together in older literature because the purified peptide was first obtained from that mixture.
The precursor, prothymosin alpha, is encoded by the PTMA gene in humans. The 28-residue peptide corresponds to the N-terminal segment released from that larger protein.
It is produced as a fragment of prothymosin alpha and is present in many tissues. Circulating concentrations are low, which makes routine measurement difficult.
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.