salvage pathway raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2026-02-21. Anything still debated is marked as such rather than presented as settled.
In the NAD+ salvage pathway, the enzyme NAMPT converts nicotinamide and a phosphate-donor molecule into NMN. A second enzyme, NMNAT, then converts NMN into NAD+. Nicotinamide riboside can also enter this route after being converted to NMN by nicotinamide riboside kinases. Because NMN sits at a junction between precursor uptake and NAD+ formation, its cellular concentration is tightly linked to enzyme activity and tissue type. NAD+ participates in redox reactions, signaling, and DNA repair, and its levels decline with age in some animal models, though human evidence remains more limited and context-dependent.
Research interest in NMN increased after animal studies reported that oral or injected NMN can raise NAD+ levels in some tissues. How NMN is absorbed and distributed in humans is not fully established. Some evidence suggests extracellular NMN may be dephosphorylated to nicotinamide riboside before cellular uptake, while other studies propose specific transport routes. Direct human data on these mechanisms remain limited. Regulatory status also varies: in some countries NMN is treated as a dietary supplement, while elsewhere it is restricted or requires approval, and these differences affect labeling, sale, and research.
Quality control for NMN typically checks identity, assay purity, residual solvents, heavy metals, and microbial limits, depending on the intended use and market. A certificate of analysis may report appearance, solubility, water content, and storage recommendations. Independent verification can compare chromatographic retention time and mass spectrum against a certified reference standard. Regulatory expectations differ between research chemicals, dietary ingredients, and pharmaceutical products. Impurity profiles and stability data are often requested for product approval, and open questions remain about how best to standardize NMN measurements across laboratories.
NMN is a polar, water-soluble nucleotide. In solid form it is usually a white to off-white powder. The compound is sensitive to heat, light, moisture, and extremes of pH, and aqueous solutions tend to degrade faster than dry material. Recommended storage for research samples is typically -20 °C or below in a sealed, desiccated container protected from light. Repeated freeze-thaw cycles should be avoided, and these handling practices help maintain identity and purity during laboratory use.
Analytical identification of NMN commonly uses high-performance liquid chromatography with ultraviolet detection, liquid chromatography-mass spectrometry, and nuclear magnetic resonance spectroscopy; HPLC can estimate purity by peak area, while mass spectrometry confirms molecular mass and fragmentation. NMR provides structural confirmation. Because NMN is charged, ion-pairing reagents or hydrophilic interaction liquid chromatography columns can improve retention and peak shape. In biological samples, LC-MS/MS with stable isotope internal standards is often used to quantify NMN and related NAD+ metabolites. Method validation is important because matrix effects and rapid enzymatic interconversion can complicate measurements.
| Property | Value | Notes |
|---|---|---|
| Chemical name | Nicotinamide mononucleotide | Common name; beta form often denoted beta-NMN |
| Chemical formula | C11H15N2O8P | As free acid; salt forms differ |
| Molar mass | 334.22 g/mol | Calculated for the free acid |
| CAS Registry Number | 1094-61-7 | For beta-nicotinamide mononucleotide |
| Biochemical role | NAD+ intermediate | Participates in the salvage biosynthesis pathway |
Natural sources of NMN include mammals, plants, and microorganisms, where it functions as an intermediate in NAD+ salvage and biosynthesis pathways. In mammals, the enzyme nicotinamide phosphoribosyltransferase produces NMN from nicotinamide and phosphoribosyl pyrophosphate. NMN is then converted to NAD+ by nicotinamide mononucleotide adenylyltransferase. Some foods contain measurable NMN, but reported amounts vary widely by species, tissue, and analytical method. The extent to which dietary NMN contributes to cellular NAD+ pools remains an open research question.
Chemically, NMN is described by the molecular formula C11H15N2O8P and a molecular mass near 334.22 g/mol. The beta anomer has a CAS Registry Number of 1094-61-7. It is typically supplied as a white to off-white powder for laboratory use. The molecule carries a phosphate group and a positively charged nicotinamide ring, giving it polar and water-soluble character. These properties influence how it is detected, purified, and stored in research and analytical laboratories.
Common laboratory methods for NMN include high-performance liquid chromatography with ultraviolet detection, liquid chromatography coupled to mass spectrometry, and nuclear magnetic resonance spectroscopy. Because the nicotinamide ring absorbs ultraviolet light, HPLC-UV at wavelengths near 260 nm can be used for purity assessment. LC-MS and LC-MS/MS provide greater sensitivity and are often applied to biological samples. Identification typically relies on matching retention time, mass-to-charge ratio, and fragmentation pattern to a reference standard.
NMN is generally handled as a hygroscopic and light-sensitive solid in laboratory settings. Recommended storage is typically at -20°C or below, often under desiccation and protected from light. Aqueous solutions are less stable than the solid and may degrade through hydrolysis or other pathways, so fresh preparation is common for analytical work. Repeated freeze-thaw cycles can reduce sample integrity. Stability depends on pH, temperature, buffer composition, and the presence of metal ions, so specific shelf-life values should be determined experimentally rather than assumed.
Biosynthesis is chemical synthesis occurring in biological contexts. It most often refers to multi-step, enzyme-catalyzed processes where chemical substances absorbed as nutrients (or previously converted through biosynthesis) serve as enzyme substrates, with conversion by the living organism either into simpler or more complex products. Examples of biosynthetic pathways include those for the production of amino acids, lipid membrane components, and nucleotides, but also for the production of all classes of biological macromolecules, and of acetyl-coenzyme A, adenosine triphosphate, nicotinamide adenine dinucleotide and other key intermediate and transactional molecules needed for metabolism. Thus, in biosynthesis, any of an array of compounds, from simple to complex, are converted into other compounds, and so it includes both the anabolism and catabolism (building up and breaking down) of complex molecules (including macromolecules). Biosynthetic processes are often represented via charts of metabolic pathways. A particular biosynthetic pathway may be located within a single cellular organelle (e.g., mitochondrial fatty acid synthesis pathways), while others involve enzymes that are located across an array of cellular organelles and structures (e.g., the biosynthesis of glycosylated cell surface proteins).
Most young octopuses hatch as paralarvae, Octopus larvae in particular are planktonic for weeks or months. Larvae feed on shrimp, isopods and amphipods, eventually settling on the ocean floor to mature. Species that produce larger eggs instead hatch as benthic animals similar to the adults. These include the southern blue-ringed, Caribbean reef, California two-spot and Eledone moschata.
== Medical uses == Olaratumab is used in combination with doxorubicin for the treatment of adults with advanced soft-tissue sarcoma (STS) who cannot be cured by cancer surgery or radiation therapy, and who have not been previously treated with doxorubicin. In a randomised controlled trial with 133 STS patients, olaratumab plus doxorubicin improved the median of progression-free survival from 4.1 to 6.6 months as compared to doxorubicin alone (p = 0.0615, narrowly missing statistical significance), and overall survival from 14.7 to 26.5 months (p = 0.0003, highly significant). However, the ANNOUNCE phase 3 trial did not find any advantage in adding olaratumab to doxorubicin. Therefore, in January 2019, FDA and EMA decided to recommend against starting olaratumab for soft tissue sarcoma. In April 2019 the European Medicines Agency explicitly requested the marketing authorisation of the medicine to be revoked. Shortly afterwards the German Physician's Medicines Commission reported that olaratumab will be removed from the German market "in a few weeks" and asked doctors not to treat new patients with this drug outside of clinical trials. Lilly subsequently voluntarily withdrew its approval in the United States.
==== Mexico ==== Two types of cider (sidra) are sold in Mexico. One type is a popular apple-flavoured, carbonated soft drink, sold under a number of soft drink brands, such as Sidral Mundet and Manzana Lift (both Coca-Cola FEMSA brands), Manzanita Sol (owned by PepsiCo), and Sidral Aga from Group AGA. The other type, alcoholic sidra, is a sparkling cider typically sold in Champagne-style bottles with an alcohol content comparable to beer. Sidra was, due to the expense of imported champagne, sometimes used as a substitute for New Year's Eve toasts in Mexico, as it is also a sweet, fruity drink. However, now the practice is to drink cider on Christmas Eve, celebrated with the family, and champagne on New Year's celebrated with friends. Cider beverages form a very small share of the Mexican alcoholic beverage market, with the figures for 2009 volume sales amounting to only 3.8 million litres.
The column was adapted for the 2004 TV series House M.D., for which Sanders served as a medical consultant for the show. Her work also has resulted in a documentary series. A Netflix documentary series titled Diagnosis was released in August 2019. Produced by the New York Times, each episode follows Dr. Lisa Sanders as she seeks to diagnose patients with difficult symptoms. In addition to writing a column for The New York Times, Sanders has written 4 books related to medicine.
Sources: en.wikipedia.org
The EC-135 Looking Glass aircraft were equipped with the Airborne Launch Control System, capable of transmitting launch commands to U.S. ground-based intercontinental ballistic missiles (ICBMs) in the event that the ground launch control centers were rendered inoperable. The Looking Glass was also designed to help ensure continuity and reconstitution of the US government in the event of a nuclear attack on North America. Although the two types of aircraft are distinct, the Doomsday Plane nickname is also frequently associated with the Boeing E-4 "Nightwatch" Advanced Airborne Command Post mission and aircraft. The Looking Glass was the anchor in the World Wide Airborne Command Post (WWABNCP) network. This network of specially equipped EC-135 aircraft launched from ground alert status, and established air-to-air wireless network connections in the event of a U.S. national emergency. Members of the WWABNCP network included:
The anionic component of the salt has a certain significance in the manifestation of both general toxic and embryotoxic and teratogenic effects of lithium salts. For example, lithium oxybutyrate is characterized by a more pronounced general toxic effect at almost all times of administration and embryotoxic effect when administered during the period of organogenesis. Lithium carbonate has a more pronounced effect when administered at the early stages of embryogenesis.
TAAR1 also couples G-protein alpha subunit G13; when triggered by amphetamine, this pathway activates Ras homolog A (RhoA) and its downstream protein kinase, Rho-associated coiled-coil kinase (ROCK), an effect that internalizes both DAT and the neuronal glutamate transporter EAAT3. Transporter internalization via TAAR1's G13-coupled pathway is transient because Gs-cAMP-PKA signaling functionally inhibits RhoA's downstream activity; once intracellular cAMP sufficiently accumulates, PKA is activated and phosphorylates RhoA, thereby terminating ROCK-mediated transporter internalization. In addition to presynaptic actions that regulate DAT, TAAR1 activation exerts a somatodendritic inhibitory influence on midbrain dopamine neurons by reducing their firing rate via G protein-coupled inwardly-rectifying potassium channels, an effect that is expected to reduce action potential-dependent (vesicular) dopamine release into the synaptic cleft. Amphetamine's effect on intracellular calcium is associated with DAT phosphorylation through Ca2+/calmodulin-dependent protein kinase II alpha (CAMKIIα), in turn producing dopamine efflux. Because conventional PKC isoforms can be activated by Ca2+ and diacylglycerol, elevated intracellular calcium can promote PKC-dependent DAT phosphorylation independent of TAAR1.
JCAMP-DX are text-based file formats created by JCAMP for storing spectroscopic data. It started as a file format for Infrared spectroscopy. It was later expanded to cover Nuclear magnetic resonance spectroscopy, mass spectrometry, electron magnetic resonance and circular dichroism spectroscopy. Later extensions for good laboratory practice were added to cover contract laboratories needs. Despite all efforts to create an easy to comprehend standards, most vendor implementations differ slightly. An open source implementation exists in Java.
Sources: en.wikipedia.org
Cyclone Tam causes significant power outages in Northland and leads to the cancellation of flights and ferry services in Auckland. 17 April – Cyclone Tam causes over 6,000 properties in Northland, the Coromandel Peninsula, Bay of Plenty and Gisborne to lose power overnight. 18 April – Cyclone Tam causes flooding to roads and highways in the Coromandel Peninsula. Flooding and strong-winds are also reported in the Far North District, leading to road closures and flight disruptions. 19 April – Cyclone Tam causes flooding, thunderstorms and travel disruptions in Auckland. Local authorities issue an emergency alert. 20 April: Auckland authorities issue a second emergency alert in response to flooding and thunderstorms caused by Cyclone Tam. 70 protesters affiliated with the Happy Valley Coalition occupy a fast-tracked coal mine on the Denniston Plateau near Westport. 21 April – Cyclone Tam begins easing, despite heavy rain and thunderstorms across New Zealand. Power companies work on restoring power to Northland homes. The Auckland Council inspects 16 flood-damaged properties. 22 April – Power companies restore power to most houses in Northland, with 25 Far North homes remaining disconnected. 23 April – Police remove the last remaining protesters from a coal mine in the Denniston Plateau. Seven people were charged with trespassing while three were arrested. 24 April – A fire breaks out at a recycling plant in the Wairau Valley in Auckland's North Shore, causing significant damage including a chemical spill contaminating several beaches in the North Shore.
History of radiochemistry – history of the chemistry of radioactive materials, where radioactive isotopes of elements are used to study the properties and chemical reactions of non-radioactive isotopes (often within radiochemistry the absence of radioactivity leads to a substance being described as being inactive as the isotopes are stable). History of organic chemistry – history of the study of the structure, properties, composition, reactions, and preparation (by synthesis or by other means) of carbon-based compounds, hydrocarbons, and their derivatives. History of petrochemistry – history of the branch of chemistry that studies the transformation of crude oil (petroleum) and natural gas into useful products or raw materials. History of organometallic chemistry – history of the study of chemical compounds containing bonds between carbon and a metal. History of photochemistry – history of the study of chemical reactions that proceed with the absorption of light by atoms or molecules. History of physical chemistry – history of the study of macroscopic, atomic, subatomic, and particulate phenomena in chemical systems in terms of physical laws and concepts. History of chemical kinetics – history of the study of rates of chemical processes. History of chemical thermodynamics – history of the study of the interrelation of heat and work with chemical reactions or with physical changes of state within the confines of the laws of thermodynamics.
=== EC 1.3.5 With a quinone or related compound as acceptor === EC 1.3.5.1: succinate dehydrogenase (quinone) EC 1.3.5.2: dihydroorotate dehydrogenase (quinone) EC 1.3.5.3: protoporphyrinogen IX dehydrogenase (menaquinone) EC 1.3.5.4: fumarate reductase (quinol) EC 1.3.5.5: 15-cis-phytoene desaturase EC 1.3.5.6: 9,9'-dicis-zeta-carotene desaturase
Sources: en.wikipedia.org
Nicotinamide mononucleotide is a nucleotide intermediate in the biosynthesis of NAD+. It consists of nicotinamide attached to a ribose phosphate unit. NMN occurs naturally in cells and is present at low levels in some foods.
NMN is a direct precursor in the NAD+ salvage pathway. Enzymes called NMNAT convert NMN into NAD+, a coenzyme used in metabolism and cell signaling. Raising NMN may increase NAD+ in some experimental settings, but the effect depends on tissue and organism.
No. Nicotinamide riboside is a related compound that lacks the phosphate group present in NMN. Cells can convert nicotinamide riboside into NMN, and both compounds feed into NAD+ production through overlapping routes.
Solid NMN is generally stored in a sealed container at -20 °C or below, protected from light and moisture. Some suppliers recommend a desiccant and inert gas. Aqueous solutions are less stable and are often prepared fresh.