Multilayer film was fabricated on an electrode surface by alternate layer-by-layer（LBL） adsorption of polycationic redox polymer（PEI-Fc） and dye-linked L-proline dehydrogenase（L-proDH）.The electrochemistry of th...Multilayer film was fabricated on an electrode surface by alternate layer-by-layer（LBL） adsorption of polycationic redox polymer（PEI-Fc） and dye-linked L-proline dehydrogenase（L-proDH）.The electrochemistry of the PEI-Fc/L-proDH multilayer modified electrode was investigated by cyclic voltammetry,and the enzyme catalysis mediated by the redox polymer was studied in a solution containing L-proline.It was observed that electron communication between L-proDH and the electrode was achieved with the help of PEI-Fc.A mathematical expression for the current response was evaluated based on the Michaelis-Menten kinetics mode,and the calculated currents fitted well with the experimental data.The kinetic analysis indicates that only a small fraction of the immobilized enzyme was efficiently electrically wired by the redox polymer.展开更多
Peanut （Arachis hypogaea L.）, an improtant oil crop, usually encounters drought stress in the process of growth and development, especially at pre-flowering stage. In order to gain insight into the drought tolerance...Peanut （Arachis hypogaea L.）, an improtant oil crop, usually encounters drought stress in the process of growth and development, especially at pre-flowering stage. In order to gain insight into the drought tolerance potentials based on osmolyte accumulation and metabolism of proline aspects of peanut, pot experiments were conducted with a split-plot design in Tai＇an, Shangdong Province, China in 2013 and 2014. Pre-flowering drought （PFD） stress and optinum irrigation （control, CK） were served as the main plots and the two peanut cultivars Shanhua 11 and Hua 17 served as sub-plots. Shanhua 11 was drought-tolerant cultivar and Hua 17 was drought-sensitive. The content of soluble sugars, soluble protein, free proline and other free amino acids, the activities of enzymes involved in proline metabolism, and malondialdehyde （MDA） content and ion leakage were all investigated in the two cultivars at pre-flowering stage. Results showed that PFD stress significantly increased the levels of soluble protein, free proline and free amino acid, and increased Al-pyrroline-5-car- boxylate synthetase （P-5-CS, EC 2.7.2.11） activity in the leaves of drought-tolerant and drought-sensitive cultivars. The activity of proline dehydrogenase （proDH） （EC 1.5.99.8） decreased under PFD stress in both cultivars. The leaves of the tolerant cultivar maintained higher increments of osmolyte levels, lower increments of MDA content and ion leakage, as well as a higher increased proportion of P-5-CS activity and higher inhibited proportion of proDH activity under water stress compared with the drought-sensitive cultivar. The study suggests that proline accumulation in peanut leaves under PFD can be explained by the higher enhanced activities of P-5-CS and higher inhibition of proDH. The results will provide useful information for genetic improvement of peanut under drought tolerance.展开更多
基金Supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholars of the Ministry of Education,Chinathe Natural Science Foundation of Tianjin City,China(No.06YFJMJC15000)
文摘Multilayer film was fabricated on an electrode surface by alternate layer-by-layer（LBL） adsorption of polycationic redox polymer（PEI-Fc） and dye-linked L-proline dehydrogenase（L-proDH）.The electrochemistry of the PEI-Fc/L-proDH multilayer modified electrode was investigated by cyclic voltammetry,and the enzyme catalysis mediated by the redox polymer was studied in a solution containing L-proline.It was observed that electron communication between L-proDH and the electrode was achieved with the help of PEI-Fc.A mathematical expression for the current response was evaluated based on the Michaelis-Menten kinetics mode,and the calculated currents fitted well with the experimental data.The kinetic analysis indicates that only a small fraction of the immobilized enzyme was efficiently electrically wired by the redox polymer.
基金financial support from the National Natural Science Foundation of China (31201167)the earmarked foud for the China Agriculture Research System (CARS-14)Taishan Scholar Seed Industry Projects in Shandong Province,China (Shandong [2014] 126)
文摘Peanut （Arachis hypogaea L.）, an improtant oil crop, usually encounters drought stress in the process of growth and development, especially at pre-flowering stage. In order to gain insight into the drought tolerance potentials based on osmolyte accumulation and metabolism of proline aspects of peanut, pot experiments were conducted with a split-plot design in Tai＇an, Shangdong Province, China in 2013 and 2014. Pre-flowering drought （PFD） stress and optinum irrigation （control, CK） were served as the main plots and the two peanut cultivars Shanhua 11 and Hua 17 served as sub-plots. Shanhua 11 was drought-tolerant cultivar and Hua 17 was drought-sensitive. The content of soluble sugars, soluble protein, free proline and other free amino acids, the activities of enzymes involved in proline metabolism, and malondialdehyde （MDA） content and ion leakage were all investigated in the two cultivars at pre-flowering stage. Results showed that PFD stress significantly increased the levels of soluble protein, free proline and free amino acid, and increased Al-pyrroline-5-car- boxylate synthetase （P-5-CS, EC 2.7.2.11） activity in the leaves of drought-tolerant and drought-sensitive cultivars. The activity of proline dehydrogenase （proDH） （EC 1.5.99.8） decreased under PFD stress in both cultivars. The leaves of the tolerant cultivar maintained higher increments of osmolyte levels, lower increments of MDA content and ion leakage, as well as a higher increased proportion of P-5-CS activity and higher inhibited proportion of proDH activity under water stress compared with the drought-sensitive cultivar. The study suggests that proline accumulation in peanut leaves under PFD can be explained by the higher enhanced activities of P-5-CS and higher inhibition of proDH. The results will provide useful information for genetic improvement of peanut under drought tolerance.
