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Calorimetry studies of a chemical oscillatory system
The effect of putrescine on KSCN-H2O2-CuSO4-NaOH reactions
Abstract
The effect of putrescine (PUT) on KSCN-H2O2-CuSO4-NaOH oscillating system was investigated by calorimetric method. The oscillating reaction was monitored in a closed reactor with stirring, and the result showed that the oscillating period was linearly related with putrescine concentration and the numbers of oscillation decreased with increase in putrescine concentration. When [PUT]=2.83�10−4 M, no oscillation was observed. A possible mechanism is proposed that putrescine is a scavenger of the active-oxygen species. The result of numerical simulation by a simplified mechanism consisting of 18 kinetic steps and 16 variables is consistent with the experimental findings.
/kg. Tryptamine (TRY), phenylethylamine (PHE), putrescine (PUT), cadaverine (CAD), histamine (HIS), tyramine (TYR), spermidine (SPD), and spermine (SPM) are the eight biogenic amines commonly existed in foods. In order to detect the content of biogenic amines in
The effect of cold-stress (2°C, 7 days cold-hardening) on the level of polyamines in different varieties of wheat and genetically modified wheat samples (chromosome substitution lines, deletion lines, recombinant lines) has been investigated. Biogenic amines (spermine, spermidine, putrescine, and agmatine) were determined as the dansyl derivatives by stepwise gradient elution with the Personal OPLC BS 50 Chromatograph. Short-term cold-hardening caused characteristic changes in free polyamine content of wheat genotypes. The total free polyamine content was significantly lower in the cold-hardened samples than in the control samples. It seems that accumulation of spermine and agmatine might be good markers of cold sensitivity.
Two wheat cultivars ( Triticum aestivum L. cv. Chinese Spring and Cappelle Desprez) differing in drought stress tolerance were treated with two concentrations of cadmium (10 −7 and 10 −3 m to investigate whether there is also any difference in their heavy-metal tolerance. Overpressured layer chromatography (OPLC) with off-line fluorescence detection was used to monitor cadmium stress-induced changes in the polyamine content of wheat seedlings. Significant differences were found between the spermidine (Spd) and putrescine (Put) content of the two wheat cultivars. The Spd content of the moderately drought-tolerant Chinese Spring increased both in shoots and roots at the higher Cd concentration compared with the control whereas in the drought-sensitive Cappelle Desprez the Spd level was reduced by both Cd treatments. Put content increased with the amount of Cd to which the roots of Chinese Spring wheat were exposed. In the Cappelle Desprez cultivar the Put content of both organs was higher at both Cd concentrations compared with the control.
Simple, rapid and selective NP-TLC and RP-TLC methods are described for analysis of l -arginine, its primary metabolites (l -citrulline, l -glutamine, l -ornithine, asymmetric N G , N G -dimethyl-l -arginine, symmetric N G , N G ′-dimethyl-l -arginine, N G -nitro-l -arginine, N G -hydroxy-l -arginine, N G -monomethyl-l -arginine, agmatine, putrescine, spermidine, spermine, and creatine) and selected drugs (dexamethasone, prednisolone, furosemide, vancomycin, amikacin, fluconazole, digoxin, captopril, dipyrone, metoprolol, and sildenafil), in different therapeutic groups, in model solutions and in spiked human urine. NP-TLC and RP-TLC methods have been used to study the retention of the substances. A variety of mobile phase systems were evaluated for separation of ARG and its metabolites — methanol-50% acetic acid 3:1 ( v/v ) on silica gel and 5% acetic acid-methanol-acetonitrile 50:35:15 ( v/v ) on RP-18 — and for separation of the drugs — acetonitrile-water 2:3 ( v/v ) on silica gel. The effects on selectivity of the polar modifier of mobile phases were also studied.
-007-8518-5 . 12. Jingyan , S , Yuwen , L , Jie , L , Zhiyong , W , Cunxin , W 2007 Calorimetry studies of a chemical oscillatory system: the effect of putrescine on KSCN–H 2 O 2 –CuSO 4 –NaOH reactions . J Therm Anal Calorim
biogenic amines are small molecular weight organic bases. They can have different structures, which are: aliphatic (putrescine, cadaverine, spermidine), aromatic (tyramine, phenylethylamine) or heterocyclic (histamine, tryptamine). They are formed during
Introduction Spermidine alkaloids are polyamine heterocycles, biosynthetically derived from L-Orn or L-Arg via putrescine. The interests in the isolation and synthesis of these alkaloids result from the structural complexity and therapeutical
, growing conditions, and season of harvest. A. tanguticus may have developed the ability to produce and accumulate secondary metabolites to adapt to its environment. Accordingly, important enzymes such as the putrescine N-methyltransferase and hyoscyamine