Cadaverine dihydrochloride

All chemicals, unless otherwise stated, were of the highest quality and were used as supplied. All the standard biogenic amines (putrescine dihydrochloride, agmatine sulfate, histamine dihydrochloride, 2-phenylethylamine, tyramine hydrochloride, spermine tetrahydrochloride, tryptamine hydrochloride, spermidine trihydrochloride and cadaverine dihydrochloride) were purchased from Sigma-Aldrich (St. Louis, MO, USA). High-performance liquid chromatography (HPLC) grade ammonium acetate and acetonitrile were purchased from Merck (Damstadt, Germany).

All chemicals and solvents were of the analytical and chromatographic grade. Standard biogenic amines (agmatine sulfate, tryptamine hydrochloride, 2-phenylethylamine, putrescine dihydrochloride, cadaverine dihydrochloride, histamine dihydrochloride, tyramine hydrochloride, spermidine trihydrochloride, and spermine tetrahydrochloride), dansyl chloride, and acetone were purchased from Sigma-Aldrich (St. Louis, MO, USA). Sodium hydroxide, sodium hydrogen carbonate, ammonium hydroxide, and perchloric acid were purchased from Junsei Chemicals (Tokyo, Japan). High-performance liquid chromatography (HPLC) grade acetonitrile and ammonium acetate were obtained from Merck (Darmstadt, Germany). Nutrient agar was purchased from Difco (Sparks, MD, USA). API kits were purchased from BioMerieux (Marcy I’ Etoile, France).

Biogenic amine standards (histamine dihydrochloride (HIS), tryptamine hydrochloride (TRP), 2-phenylethylamine (2-PHE), putrescine dihydrochloride (PUT), cadaverine dihydrochloride (CAD), tyramine hydrochloride (TYR), spermidine trihydrochloride (SPD), and spermine tetrahydrochloride (SPM)) and dansyl chloride were obtained from Sigma-Aldrich Chemical Co. (St. Louis, MO, USA). Perchloric acid, 25% ammonium hydroxide solution, sodium hydroxide sodium hydrogen carbonate, and diethyl ether were acquired from Daejung Chemical Co. (Siheung, Korea). Acetone and acetonitrile (High-performance liquid chromatography (HPLC) grade) were purchased from Tedia Co. (Fairfield, OH, USA). Compound mixtures of amino acids, borate buffer, o-phthalaldehyde (OPA) and 9-fluorenylmethoxycarbonyl chloride (FMOC-Cl) were obtained from Agilent Technologies (Andover, MA, USA).

Chloroauric acid tetrahydrate (HAuCl₄·4H₂O) was purchased from Sangon Biotech (Shanghai, China). Histamine dihydrochloride, histidine, putrescine dihydrochloride, cadaverine dihydrochloride, 2-Phenylethylamine hydrochloride, and tyramine hydrochloride were obtained from Sigma (St. Louis, MO, USA) (http://www.sigmaaldrich.com). Trisodium citrate and NaCl were purchased from Tianjin Chemical Reagent Co., Ltd. (Tianjin, China). Salmon samples were purchased from a local aquatic products market. Moreover, Milli-Q-purified water (18.2 MΩcm) was used throughout the experiments.

Rabbit anti-occludin polyclonal IgG was acquired from Santa Cruz Biotechnology (CA, USA). Rabbit anti-glyceraldehyde 3-phosphate dehydrogenase (GAPDH) polyclonal IgG was purchased from XianZhi Biotechnology (Hangzhou, China). Rabbit anti-β-actin polyclonal IgG was acquired from Biosynthesis Biotechnology (Beijing, China), Horseradish peroxidase-labeled goat anti-rabbit IgG was obtained from ZSGB-Bio (Beijing, China).
Unconjugated bilirubin (UCB), biliverdin hydrochloride, peroxidase (POD), o-dianisidine dihydrochloride, cadaverine dihydrochloride, nicotinamide adenine dinucleotide (NAD), diamine oxidase (DAO) standard and D-Lactic dehydrogenase (D-Lac) standard were obtained from Sigma-Aldrich (Shanghai, China). Bilirubin ditaurate disodium was purchased from Frontier Scientific (Logan, Utah, USA). Dulbecco's phosphate buffered saline (PBS) and pentobarbital sodium were purchased from Solarbio (Beijing, China). All other reagents and solvents were purchased from J&k scientific (Beijing, China).

Stock standard solutions of BA, including tryptamine, β-phenylethylamine hydrochloride, putrescine dihydrochloride, cadaverine dihydrochloride, histamine dihydrochloride, tyramine hydrochloride, spermidine trihydrochloride, and spermine tetrahydrochloride (all from Sigma-Aldrich), were separately prepared at 10,000 mg/L concentration in deionized water. Working solutions at 1000 mg/L concentration were prepared by diluting 1 mL of each stock solution in deionized water to bring to a final volume of 10 mL. The concentrations of all standard solutions used were 0, 10, 50, 100, and 1000 mg/L. In addition, 1,7-diaminoheptane (Sigma-Aldrich) served as an internal standard.