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Updated 2026-05-29. Numbers and descriptions here follow the published literature rather than marketing material.
After reconstitution, solutions are usually divided into single-use aliquots to limit repeated handling. Each aliquot is stored at a temperature appropriate for the peptide, with -20 °C or -80 °C common for longer-term laboratory storage. Freeze-thaw cycles are minimized because they can cause aggregation, precipitation, or loss of activity. Temperature monitoring and documented storage conditions support reproducibility across experiments. When a peptide is removed from storage, it is typically allowed to equilibrate before opening to reduce condensation.
Receiving a peptide begins with recording its identity, lot number, quantity, and arrival condition. Dry material is often kept in sealed containers with desiccant and an inert headspace to limit moisture and oxygen. Containers should be compatible with the peptide and solvent; some peptides adsorb to certain plastics or glass. Labels should include date, concentration, solvent, and storage location. A centralized inventory with temperature logs helps prevent loss and mix-ups.
Temperature is a primary factor in peptide storage. Lower temperatures reduce molecular motion and slow degradation reactions, but freezing can concentrate solutes and promote aggregation. Lyophilized powders are commonly held at -20°C, whereas solutions are often kept at -80°C. Repeated freeze-thaw cycles are harmful because ice crystal formation and pH shifts can damage the peptide. The glass transition temperature of a lyophilized cake influences its stability; below this temperature, molecular mobility is restricted. For solutions, the choice between -20°C and -80°C depends on the peptide's sensitivity and the intended storage duration.
Moisture, oxygen, and light also affect peptide integrity. Lyophilized powders absorb water from the air, which can enable hydrolysis and conformational changes. Oxygen promotes oxidation of sensitive residues, so storage under inert gas or in sealed vials is common. Light exposure can cause photodegradation, particularly for peptides containing aromatic amino acids. Buffer choice and pH influence charge state and solubility; extremes of pH accelerate deamidation and hydrolysis. Adding stabilizers such as sugars or polyols can protect the peptide during freezing and drying. Optimal conditions are determined empirically for each peptide.
Peptides are short chains of amino acids that can undergo both chemical and physical degradation. Chemical pathways include hydrolysis of peptide bonds, oxidation of methionine or cysteine residues, deamidation of asparagine or glutamine, and isomerization of aspartate. Physical instability leads to aggregation, precipitation, or adsorption to surfaces. The rate of these processes depends on the peptide sequence, the formulation, and the storage environment. Because each peptide has a unique composition, no single storage condition applies to all peptides. Stability studies are therefore conducted to define suitable conditions for each specific molecule.
| Property | Value | Notes |
|---|---|---|
| Container material | Glass or inert plastic | Compatibility depends on peptide and solvent |
| Headspace gas | Nitrogen or argon | Used to limit oxygen exposure |
| Common reconstitution solvent | Water or buffered aqueous solution | Organic co-solvents may be needed for hydrophobic peptides |
| Freeze-thaw stability | Varies by peptide | Aliquoting reduces repeated cycles |
| Documentation | Lot, date, concentration, storage location | Supports traceability and reproducibility |
Handling begins before a peptide arrives at the bench. Containers should be inspected for cracks, loose caps, or visible moisture, and labels should record identity, lot, and receipt date. Lyophilized material is often allowed to equilibrate to room temperature before opening to prevent condensation on the powder. Gloves and a clean workspace reduce contamination and static-related loss. Once opened, the vial may be purged with inert gas and resealed if the peptide is sensitive to oxygen or humidity. These steps are procedural safeguards rather than guarantees of stability.
Reconstitution introduces new risks because the peptide contacts solvent, air, and container surfaces. The chosen solvent should match the peptide's solubility profile, and buffer salts, pH, and ionic strength can affect dissolution and subsequent stability. Gentle mixing is preferred over vigorous vortexing, which can create interfaces and shear. If the solution is not clear, the cause may be incomplete dissolution, aggregation, or insoluble counter-ions rather than a simple concentration problem. Filtration is sometimes used, but filters can adsorb peptides and alter measured concentration.
Peptides are short chains of amino acids whose physical and chemical stability depends on sequence, length, and conformation. The amide backbone can hydrolyze under acidic or basic conditions, while side chains such as methionine, cysteine, and tryptophan are prone to oxidation. Aggregation may occur when hydrophobic regions associate, especially near surfaces or at high concentration. Because these pathways differ among peptides, no single storage condition applies to all sequences. Stability studies therefore examine each peptide under defined temperature, pH, and humidity ranges.
Temperature is a primary variable because most degradation reactions slow as thermal energy decreases. Lyophilized powders are commonly held at -20 °C for routine work and at -80 °C for longer archival periods, though exact recommendations depend on the peptide. Solutions are less stable than dry powders in many cases, and repeated freeze-thaw cycles can promote aggregation or precipitation. Inert atmospheres, such as argon or nitrogen, can limit oxidation for oxygen-sensitive sequences. Desiccants reduce water activity, which lowers hydrolysis rates during storage.
Light exposure can damage aromatic residues and certain labels, so amber vials or opaque containers are often used. pH control matters in solution, as extreme acidity or alkalinity accelerates backbone cleavage; buffers may also introduce ions that affect solubility. Microbial growth is a concern for aqueous preparations that lack preservatives, though many research peptides are handled in sterile or low-bioburden conditions. Container materials can adsorb peptides, particularly hydrophobic or positively charged sequences, reducing recovery. These factors interact, meaning storage decisions balance chemical stability, physical state, and intended use.
Reconstitution is the process of dissolving a dried peptide in a suitable solvent. The choice of solvent depends on solubility, charge, and sequence; sterile water is common, while buffers or small amounts of organic solvent may be needed for hydrophobic peptides. Adding solvent gently down the vial wall and mixing by inversion or gentle swirling reduces foaming and shear. Vortexing or vigorous pipetting can denature some peptides or promote aggregation. The resulting solution should be visually inspected for particles, turbidity, and complete dissolution before use.
After reconstitution, solutions are usually divided into single-use aliquots to avoid repeated freeze-thaw cycles. Aliquots should be labeled with peptide identity, concentration, solvent, and date, then stored at the temperature specified by the supplier or protocol. Many peptides tolerate -20 °C for short periods, while -80 °C is preferred for longer storage. Frost-free freezers are generally avoided because temperature fluctuations can stress samples. Aseptic technique and sterile filters reduce microbial contamination, though filtration can also remove aggregated material or bind some peptides.
Maisie Mosco (7 December 1924 – 31 October 2011) wrote 16 novels between 1979 and 1998. These include the 'Almonds and Raisins' series (Almonds & Raisins, Scattered Seed, Children's Children, Out of the Ashes, and New Beginnings), about a Jewish family who around 1900 fled anti-Jewish pogroms in the Russian Empire and emigrated to north Manchester in England. These books contained elements of her own family history and were dramatized for BBC Radio 4. Michael Moritz (b. 1954) billionaire venture capitalist, philanthropist, author, journalist; works for Sequoia Capital, wrote history of Apple Inc., The Little Kingdom, and Going for Broke: Lee Iacocca's Battle to Save Chrysler; was writer at Time magazine and member of board of directors of Google; founded Technologic Partners; named as the No. 1 venture capitalist on the Forbes Midas List; appointed Knight Commander of the Order of the British Empire (KBE). Claus Moser, Baron Moser, (24 November 1922 – 4 September 2015) was a British statistician, scholar and author who made major contributions in both academia and the Civil Service.
== Discovery == Identified as a marker of epithelial differentiation upon its discovery in the 1990s, galectin-7 was first characterized for its increased expression in keratinocytes following UVB irradiation. Only later was its dual role in cancers recognized.
=== International rail transport resumption === In January 2022, the first freight trains between North Korea and China resumed after a two-year hold. Uiju Air Base was converted to a cargo decontamination facility for containers brought in by freight trains. A South Korean–based humanitarian organisation, the Inter-Korean Economic Cooperation Research Center (남북경제협력연구소, IKECRC), received a UN sanctions exemption to send 20 thermal imaging cameras to North Phyongan province for detection of fever symptoms, while the WHO was granted 18 more months to deliver shipments for stalled projects. In November 2022, use of the rail Korea–Russia Friendship Bridge resumed.
=== Expansion and acquisition === By 1997, Reddy's made the transition from being an API and bulk drug supplier to regulated markets like the US and the UK, and a branded formulations supplier in unregulated markets like India and Russia, into producing generics, by filing an Abbreviated New Drug Application (ANDA) in the USA. The same year, Reddy's out-licensed a molecule for clinical trials to Novo Nordisk, a Danish pharmaceutical company. It strengthened its Indian manufacturing operations by acquiring American Remedies Ltd. in 1999. This acquisition made Reddy's the third largest pharmaceutical company in India, after Ranbaxy and Glaxo (I) Ltd., with a full spectrum of pharmaceutical products, which included bulk drugs, intermediates, finished dosages, chemical synthesis, diagnostics and biotechnology. Reddy's also started exploiting Para 4 filing as a strategy in bringing new drugs to the market at a faster pace. In 1999 it submitted a Para 4 application for omeprazole, the drug that had been the cornerstone of its success in India. In December 2000, Reddy's had undertaken its first commercial launch of a generic product in the US, and its first product with market exclusivity was launched there in August 2001. The same year, it also became the first non-Japanese pharmaceutical company from the Asia-Pacific region to obtain a New York Stock Exchange listing. In 2001 Reddy's became the first Indian company to launch the generic drug, fluoxetine (a generic version of Eli Lilly and Company’s Prozac) with 180-day market exclusivity in the USA.
Sources: en.wikipedia.org
Corn (maize) became a staple food in the southeast United States and in parts of Europe. A disease that was characterized by dermatitis of sunlight-exposed skin was described in Spain in 1735 by Gaspar Casal. He attributed the cause to poor diet. In northern Italy it was named pellagra from the Lombard language (agra = holly-like or serum-like; pell = skin). In time, the disease was more closely linked specifically to corn. In the US, Joseph Goldberger was assigned to study pellagra by the Surgeon General of the United States. His studies confirmed a corn-based diet as the culprit, but he did not identify the root cause. Nicotinic acid was extracted from the liver by biochemist Conrad Elvehjem in 1937. He later identified the active ingredient, referring to it as "pellagra-preventing factor" and the "anti-blacktongue factor." It was also referred to as "vitamin PP", "vitamin P-P" and "PP-factor", all derived from the term "pellagra-preventive factor". In the late 1930s, studies by Tom Douglas Spies, Marion Blankenhorn, and Clark Cooper confirmed that nicotinic acid cured pellagra in humans. The prevalence of the disease was greatly reduced as a result. In 1942, when flour enrichment with nicotinic acid began, a headline in the popular press said "Tobacco in Your Bread." In response, the Council on Foods and Nutrition of the American Medical Association approved of the Food and Nutrition Board's new names niacin and niacin amide for use primarily by non-scientists.
Agarose is a preferred matrix for work with proteins and nucleic acids as it has a broad range of physical, chemical and thermal stability, and its lower degree of chemical complexity also makes it less likely to interact with biomolecules. Agarose is most commonly used as the medium for analytical scale electrophoretic separation in agarose gel electrophoresis. Gels made from purified agarose have a relatively large pore size, making them useful for separation of large molecules, such as proteins and protein complexes >200 kilodaltons, as well as DNA fragments >100 basepairs. Agarose is also used widely for a number of other applications, for example immunodiffusion and immunoelectrophoresis, as the agarose fibers can function as anchor for immunocomplexes.
24395Am + 2210Ne → 265−x105 + x n (x = 4, 5) After observing the alpha decays of element 105, the researchers aimed to observe spontaneous fission (SF) of the element and study the resulting fission fragments. They published a paper in February 1970, reporting multiple examples of two such activities, with half-lives of 14 ms and 2.2±0.5 s. They assigned the former activity to 242mfAm and ascribed the latter activity to an isotope of element 105. They suggested that it was unlikely that this activity could come from a transfer reaction instead of element 105, because the yield ratio for this reaction was significantly lower than that of the 242mfAm-producing transfer reaction, in accordance with theoretical predictions. To establish that this activity was not from a (22Ne,xn) reaction, the researchers bombarded a 243Am target with 18O ions; reactions producing 256103 and 257103 showed very little SF activity (matching the established data), and the reaction producing heavier 258103 and 259103 produced no SF activity at all, in line with theoretical data. The researchers concluded that the activities observed came from SF of element 105. In April 1970, a team at Lawrence Berkeley Laboratory (LBL), in Berkeley, California, United States, claimed to have synthesized element 105 by bombarding californium-249 with nitrogen-15 ions, with an alpha activity of 9.1 MeV. To ensure this activity was not from a different reaction, the team attempted other reactions: bombarding 249Cf with 14N, Pb with 15N, and Hg with 15N. They stated no such activity was found in those reactions.
Sources: en.wikipedia.org
Dry peptides are generally kept in sealed, desiccated containers at low temperature, often -20 °C or colder. Protection from light, moisture, and oxygen helps slow degradation. The exact condition depends on the peptide sequence and supplier guidance.
Aliquoting divides a solution into smaller portions so that each portion is handled once. This reduces repeated freeze-thaw cycles and limits contamination risk. It also makes it easier to track usage and maintain consistent test conditions.
Refreezing is possible for some peptides but can promote aggregation or precipitation. The effect depends on the peptide, solvent, concentration, and freezing rate. Many laboratory protocols therefore recommend single-use aliquots instead of repeated refreezing.
Removing water reduces hydrolytic degradation and limits microbial growth. Lyophilized powders are generally more stable at higher temperatures than aqueous solutions. They also tolerate shipping with less risk of degradation.