2021 Year of the Ox

5-Fluoroorotic Acid (5-FOA) is widely used in the field of yeast molecular genetics. The toxicity of 5-FOA to yeast cells with a functioning URA3 gene which encodes orotidine-5′-P decarboxylase (OMP decarboxylase), makes it especially useful for the selection and identification of mutant yeast strains. 5-FOA is most often applied with Saccharomyces cerevisiae (URA3), although it has been used in other strains including Schizosaccharomyces pombe (URA4 and URA5), Candida albicans (URA3) and the bacterium E. coli (pyrF). The use of 5-FOA in the yeast 2-hybrid system allows for the construction of activation domain hybrid libraries to identify protein-protein interactions.

GoldBio's 6x Blue DNA Loading Dye is pre-mixed buffer designed for tracking the DNA sample during the electrophoresis on agarose or polyacrylamide gels. It contains two dyes (Xylene cyanol FF and Bromophenol blue) for tracking the DNA migration. The Xylene cyanol FF and Bromophenol blue migrate at approximately 4,000 bp and 500 bp on a standard 1% TAE agarose gel respectively (800 bp and 150 bp on a 2% TAE agarose gel respectively). The included glycerol keeps the DNA at the bottom of the well and the presence of EDTA chelates divalent metal ions to prevent the process of metal-dependent nuclease.

GoldBio's 6x Green DNA Loading Dye is a pre-mixed buffer for tracking DNA samples during the electrophoresis on agarose or polyacrylamide gels. It contains two dyes (Xylene cyanol FF and Orange G) for tracking the DNA migration. The Xylene cyanol FF and Orange G migrate at approximately 4,000 bp and 50 bp on a standard 1% TAE agarose gel respectively (800 bp and 30 bp on a 2% TAE agarose gel respectively). The included glycerol keeps the DNA at the bottom of the well and the presence of EDTA chelates divalent metal ions to prevent the process of metal-dependent nuclease.

AEBSF is an irreversible serine protease inhibitor. AEBSF has been shown to inhibit trypsin, chymotrypsin, plasmin, kallikrein and thrombin. It inhibits the active site of the enzyme through acylation. As an alternative to PMSF and DFP, AEBSF offers lower toxicity, improved solubility in water and improved stability in aqueous solutions. AEBSF has been used in cell culture in concentrations of up to 0.25 mM. Aqueous solutions are stable between pH 5-6; limited stability above pH 7.5.

Aprotinin is a monomeric globular polypeptide derived from bovine lung tissue. It consists of a chain of 58 amino acids that fold into a stable, compact tertiary structure of the 'small SS-rich" type, containing 3 disulfides, a twisted β-hairpin and a C-terminal α-helix.

Aprotinin inhibits several serine proteases, specifically trypsin, chymotrypsin, plasmin and kallikrein. Its action on kallikrein leads to the inhibition of the formation of factor XIIa. Binding is reversible with most aprotinin-protease complexes dissociating at pH >10 or < 3. Aprotinin is freely soluble in water (>10 mg/ml) as well as low ionic strength aqueous buffers.

Arginine is an essential amino acid found in food and plant sources, and many biological systems and is one of only 3 amino acids with basic side chains. Arginine is typically classified as a semi-essential or conditionally essential amino acid. Administered intravenously, Arginine has been shown to stimulate the secretion of human growth hormone and is frequently used in growth hormone stimulation tests. L-Arginine is a substrate of nitric oxide synthase, which is converted to citrulline and nitric oxide and is known to Induces insulin release by a nitric oxide-dependent mechanism.

Lysozyme is an enzyme capable of breaking down the bacterial cell wall, and is typically used to enhance protein extractions or nucleic acid extractions. It works by hydrolyzing the 1,4-β-linkages located between the N-acetylmuramic acid and the N-acetyl-D-glucosamine residues in peptidoglycan.

Gram-positive cells have an increased susceptibility to the actions of lysozyme since gram-positive cells have a higher quantity of peptidoglycan in the cell wall. Gram-negative cells are less vulnerable, but can still be hydrolyzed in the presence of EDTA.

MOPS is a buffering agent used in biochemistry and molecular biology that was selected and described by Good et al. It is a zwitterionic, morpholinic buffer that is useful for a pH range of 6.5 – 7.9 and commonly used for cell culture media, as a running buffer in electrophoresis, and for protein purification in chromatography. MOPS lacks the ability to form a complex with most metal ions and is recommended for use as a non-coordinating buffer in solutions with metal ions.

5-Bromo-4-chloro-3-indolyl β-D-galactopyranoside is most commonly known as X-Gal. X-gal is a histochemical substrate for β-galactosidase which cleaves X-Gal to yield an insoluble blue precipitate.

X-Gal is a mainstay in molecular biology cloning applications in which it is used to detect the activity of β-galactosidase. X-Gal is used to detect the insertion of foreign DNA into the lacZ region of a plasmid DNA. Insertion of DNA into the lacZ region results in the loss of β-galactosidase activity. Bacteria cells that retain active β-galactosidase will result in characteristic blue colonies. Successful disruption of the lacZα gene disrupts the α-complementation of the β-galactosidase gene and the precipitate does not form, resulting in white colonies.

Many other applications also use X-Gal as a substrate to detect β-galactosidase activity. These include β-galactosidase -antibody linked immunoassays and immunohistochemistry, coliphage detection based on β-galactosidase induction and the detection of micrometastasis formation during tumor progession.