Gene/Protein Disease Symptom Drug Enzyme Compound
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 720 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Up-regulation of the antioxidant system provides protection against NaCl-induced oxidative damage in plants. Antioxidants and activity of enzymes involved in the ascorbate-glutathione (ASC-GSH) cycle in tobacco Bright Yellow-2 (BY-2) were investigated to assess the antioxidant protection offered by exogenous proline and glycinebetaine (betaine from now on) against salt stress using cells grown in suspension culture. Reduced ascorbate (ASC) was detected in BY-2 cells but dehydroascorbate (DHA) was not. Large quantities of a reduced form of glutathione (GSH) and smaller quantities of an oxidized form of glutathione (GSSG) were detected in BY-2 cells. Salt stress significantly reduced the contents of ASC and GSH as well as activities of ASC-GSH cycle enzymes such as ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), and glutathione reductase (GR). Exogenous proline or betaine increased the activities of all enzymes except MDHAR involved in NaCl-induced ASC-GSH cycle. Levels of ASC and GSH in BY-2 cells under salt stress were lower in the presence of proline or betaine than in the absence of proline or betaine whereas there was no difference in redox status. Proline proved more effective than betaine in maintaining the activity of enzymes involved in NaCl-induced ASC-GSH cycle. Neither proline nor betaine had any direct protective effect on NaCl-induced enzyme activity involved in the antioxidant system; however, both improved salt tolerance by increasing enzyme activity. The present study, together with our earlier findings [Hoque MA, Okuma E, Banu MNA, Nakamura Y, Shimoishi Y, Murata Y. Exogenous proline mitigates the detrimental effects of salt stress more than exogenous betaine by increasing antioxidant enzyme activities. J Plant Physiol 2006;164:553-61.], suggests that proline offered greater protection against salt stress than betaine did because proline was more effective in increasing the activity of enzymes involved in the antioxidant system.
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PMID:Exogenous proline and glycinebetaine increase NaCl-induced ascorbate-glutathione cycle enzyme activities, and proline improves salt tolerance more than glycinebetaine in tobacco Bright Yellow-2 suspension-cultured cells. 1722 25

Bright red-flowered Canna indica L. plants were subjected to grow in nutrient solution supplemented with five different concentrations (0, 5, 10, 30 and 50 microM) of CuCl2 to study antioxidant defense responses of the plant. Accumulation of Cu was dose-dependent and much higher in the roots (108-191 microg g(-1) d. wt.) than in the leaves (23.36-40.43 microg g d.wt.). Total ascorbate content did not changed in both tissues, but ascorbate redox state decreased (0.570-0.640) in Cu-treated Canna roots. In contrast, both total and reduced glutathione contents increased (387-591.9 nmol g(-1) f. wt.) considerably in roots, accompanied with enhanced activities of dehydroascorbate reductase (153.3-160 nmol mg(-1) protein) and glutathione reductase (67-87.5 nmol mg(-1) protein). No significant change, however, was observed for monodehydroascorbate reductase activity in both tissues of the treated plant. The efficient scavenging of hydrogen peroxide was performed by normal (control level) activities of both ascorbate peroxidase and catalase in leaf and increased activity of only catalase in root, preventing its accumulation at toxic concentrations (despite high superoxide dismutase activity) and subsequent damage of membrane lipids by peroxidation. Together, these ensured normal dry weight of leaves and roots, indicating tolerance of Canna indica plant to Cu-induced oxidative stress.
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PMID:Studies on antioxidant enzymes in Canna indica plant under copper stress. 2400 13