To investigate the role of polyamines in pre- and post-harvest fruit development of 'Akatsuki' peach (Prunus persica (L.) Batsch.) we measured polyamine concentrations, activities of polyamine biosynthetic enzymes and expression of genes encoding these enzymes. Concentrations of the free polyamines, putrescine (Put), spermidine (Spd) and spermine (Spm) in pre-harvest fruit peaked 16 days after ...

Although gastric and intestinal contents from rats failed to show amino acid decarboxylase activity when tested against five different amino acids (glutamic acid, arginine, lysine, tyrosine, and histidine), the feces contained at least seven different amines, some known to be pharmacologically active. Putrescine, histamine, and tyramine were identified by means of paper chromatography in both i...

The metabolisms of arginine (Arg), ornithine (Orn), and putrescine were compared in a nontransgenic and a transgenic cell line of carrot (Daucus carota L.) expressing a mouse Orn decarboxylase cDNA. [14C]Arg, [14C]Orn, and [14C]putrescine were fed to cells and their rates of decarboxylation, uptake, metabolism into polyamines, and incorporation into acid-insoluble material were determined. Tran...

The amino acid L-arginine is a component of proteins and is involved in several metabolic pathways, including the urea cycle, the synthesis of creatine and the generation of nitric oxide [1]. In the last 2 years it has been established that arginine can also be decarboxylated, resulting in the formation of agmatine, 4(aminobutyl)guanidine. The enzyme arginine decarboxylase was thought to be pre...

Until recently, conversion of arginine to agmatine by arginine decarboxylase (ADC) was considered important only in plants and bacteria. In the following, we demonstrate ADC activity in the membrane-enriched fraction of brain, liver, and kidney cortex and medulla by radiochemical assay. Diamine oxidase, an enzyme shown here to metabolize agmatine, was localized by immunohistochemistry in kidney...

Treatment of the first leaves of barley (Hordeum vulgare L. cv. Golden Promise) seedlings with methyl jasmonate (MJ) led to small, but significant increases in levels of free putrescine and spermine 1 d later and to significant increases in levels of free putrescine, spermidine and spermine by 4 d following treatment. MJ-treated first leaves also exhibited significant increases in the amounts o...

This article presents an overview of the role of polyamines (PAs) in plant growth and developmental processes. The PAs, putrescine, spermidine and spermine are low molecular weight cations present in all living organisms. PAs and their biosynthetic enzymes have been implicated in a wide range of metabolic processes in plants, ranging from cell division and organogenesis to protection against st...

Polyamine (PA) titers and biosynthesis follow a basipetal decrease along the tobacco (Nicotiana tabacum) plant axis, and they also correlate negatively with cell size. On the contrary, the titers of arginine (Arg), ornithine (Orn), and arginase activity increase with age. The free (soluble)/total-PA ratios gradually increase basipetally, but the soluble conjugated decrease, with spermidine (Spd...

To understand dynamic changes in polyamines (PAs) forms and components of polyamine metabolism in zoysiagrass (Zoysia japonica Steud.) response to salt stress with exogenous spermidine (Spd) application, two Chinese zoysia cultivars, z081 and z057, were exposed to sodium chloride stress for 2, 4, 6, and 8 days. The z057 cultivar possesses higher salinity tolerance than the z081 cultivar. Salt s...

Colon epithelium is renewed within few days through asymmetric mitosis of pluripotent cells followed by differentiation and exfoliation. Absorptive colonocytes do not transport amino acids from lumen to bloodstream but import amino acids from plasma. Among amino acids, colonocytes can use L-arginine as a precursor for nitric oxide (NO) synthesis and also for polyamine synthesis through the step...