Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:1.6.5.4 (SOR)
720 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Changes in antioxidant metabolism because of the effect of salinity stress (0, 80, 160 or 240 mM NaCl) on protective enzyme activities under ambient (350 micromol mol(-1)) and elevated (700 micromol mol(-1)) CO(2) concentrations were investigated in two barley cultivars (Hordeum vulgare L., cvs Alpha and Iranis). Electrolyte leakage, peroxidation, antioxidant enzyme activities [superoxide dismutase (SOD), EC 1.15.1.1; ascorbate peroxidase (APX), EC 1.11.1.11; catalase (CAT), EC 1.11.1.6; dehydroascorbate reductase (DHAR), EC 1.8.5.1; monodehydroascorbate reductase (MDHAR), EC 1.6.5.4; glutathione reductase (GR), EC 1.6.4.2] and their isoenzymatic profiles were determined. Under salinity and ambient CO(2), upregulation of antioxidant enzymes such as SOD, APX, CAT, DHAR and GR occurred. However, this upregulation was not enough to counteract all ROS formation as both ion leakage and lipid peroxidation came into play. The higher constitutive SOD and CAT activities together with a higher contribution of Cu,Zn-SOD 1 detected in Iranis might possibly contribute and make this cultivar more salt-tolerant than Alpha. Elevated CO(2) alone had no effect on the constitutive levels of antioxidant enzymes in Iranis, whereas in Alpha it induced an increase in SOD, CAT and MDHAR together with a decrease of DHAR and GR. Under combined conditions of elevated CO(2) and salinity the oxidative damage recorded was lower, above all in Alpha, together with a lower upregulation of the antioxidant system. So it can be concluded that elevated CO(2) mitigates the oxidative stress caused by salinity, involving lower ROS generation and a better maintenance of redox homeostasis as a consequence of higher assimilation rates and lower photorespiration, being the response dependent on the cultivar analysed.
...
PMID:The oxidative stress caused by salinity in two barley cultivars is mitigated by elevated CO2. 1912 Oct 97

While polyamines (PAs) have been suggested to protect cells against Reactive Oxygen Species (ROS), their catabolism is known to generate ROS. We compared the activities of several enzymes and cellular metabolites involved in the ROS scavenging pathways in two isogenic cell lines of poplar (Populus nigraxmaximowiczii) differing in their PA contents. Whereas the control cell line was transformed with beta-glucuronidase (GUS), the other, called HP (High Putrescine), was transformed with a mouse ornithine decarboxylase (mODC) gene. The expression of mODC resulted in several-fold increased production of putrescine as well its enhanced catabolism. The two cell lines followed a similar trend of growth over the seven-day culture cycle, but the HP cells had elevated levels of soluble proteins. Accumulation of H(2)O(2) was higher in the HP cells than the control cells, and so were the activities of glutathione reductase and monodehydroascorbate reductase; the activity of ascorbate peroxidase was lower in the former. The contents of reduced glutathione and glutamate were significantly lower in the HP cells but proline was higher on some days of analysis. There was a small difference in mitochondrial activity between the two cell lines, and the HP cells showed increased membrane damage. In the HP cells, increased accumulation of Ca was concomitant with lower accumulation of K. We conclude that, while increased putrescine accumulation may have a protective role against ROS in plants, enhanced turnover of putrescine actually can make them vulnerable to increased oxidative damage.
...
PMID:Putrescine overproduction negatively impacts the oxidative state of poplar cells in culture. 1913 66

Dunaliella species accumulate carotenoids and their role in protection against photooxidative stress has been investigated extensively. By contrast, the role of other antioxidants in this alga, has received less attention. Therefore, the components of the ascorbate-glutathione cycle, along with superoxide dismutase (E.C. 1.15.1.1) and peroxidase (E.C. 1.11.1.11) activity were compared in two strains of Dunaliella salina. Strain IR-1 had two-fold higher chlorophyll and beta-carotene concentration than Gh-U. IR-1 had around four-fold higher superoxide dismutase, ascorbate peroxidase and pyrogallol peroxidase activities than Gh-U on a protein basis. Ascorbate and glutathione concentrations and redox state did not differ between strains and there was little difference in the activity of ascorbate-glutathione cycle enzymes (monodehydroascorbate reductase [E.C. 1.6.5.4], dehydroascorbate reductase [E.C. 1.8.5.1] and glutathione reductase [E.C. 1.8.1.7]). The response of these antioxidants to high light and low temperature was assessed by transferring cells from normal growth conditions (28 degrees C, photon flux density of 100 micromol m(-2) s(-1))to 28 degrees C/1200 micromol m(-2) s(-1); 13 degrees C/100 micromol m(-2) s(-1); 13 degrees C/1200 micromol m(-2) s(-1) and 28 degrees C/100 micromol m(-2) s(-1) for 24 h. Low temperature and combined high light-low temperature decreased chlorophyll and beta-carotene in both strains indicating that these treatments cause photooxidative stress. High light, low temperature and combined high light-low temperature treatments increased the total ascorbate pool by 10-50% and the total glutathione pool by 20-100% with no consistent effect on their redox state. Activities of ascorbate-glutathione cycle enzymes were not greatly affected but all the treatments increased superoxide dismutase activity. It is concluded that D. salina can partially adjust to photooxidative conditions by increasing superoxide dismutase activity, ascorbate and glutathione.
...
PMID:The effect of acute high light and low temperature stresses on the ascorbate-glutathione cycle and superoxide dismutase activity in two Dunaliella salina strains. 1923 61

Apple replant is a widespread agricultural problem documented in all of the major fruit-growing regions of the world. In order to better understand the phytotoxic mechanisms induced by allelochemicals involved with this problem, Malus prunifolia plants were grown hydroponically to the six-leaf-stage in the presence of phthalic acid (0 or 1 mM) for 5, 10, or 15 days. Apple plants were evaluated for: shoot and root length, fresh and dry weight, malondialdehyde (MDA) content, hydrogen peroxide (H(2)O(2)) content, superoxide radical (O(2) (*-)) generation rate, and antioxidant enzyme activities. Shoot and root lengths and fresh and dry weights of M. prunifolia decreased in plants exposed to phthalic acid. MDA and H(2)O(2) content increased in phthalic acid-treated plants as did the generation rate of O(2) (*-) in M. prunifolia roots. The activities of superoxide dismutase (EC 1.15.1.1), peroxidase (EC 1.11.1.7), catalase (EC 1.11.1.6), ascorbate peroxidase (EC 1.11.1.11), glutathione reductase (EC 1.6.4.2), dehydroascorbate reductase (EC 1.8.5.1), and monodehydroascorbate reductase (EC 1.6.5.4) increased in phthalic acid-stressed roots compared with control roots. These results suggest that activation of the antioxidant system by phthalic acid led to the formation of reactive oxygen species that resulted in cellular damage and the decrease of M. prunifolia growth.
...
PMID:Phthalic acid induces oxidative stress and alters the activity of some antioxidant enzymes in roots of Malus prunifolia. 1935 74

A pot experiment was carried out to investigate the effect of exogenous salicylic acid (SA) on the growth, photosynthesis, oxidative stress and responses of chloroplastic antioxidant defense system of maize (Zea mays L.) plants grown in a nickel (Ni)-contaminated soil. The results indicate that exogenous SA significantly decreased the reduction in dry weight, chlorophyll and beta-carotene contents, and net photosynthetic rate of the Ni-stressed maize, demonstrating an alleviating effect of SA on Ni toxicity of plants. Superoxide anion generation rate, H(2)O(2) and malondialdehyde (MDA) contents, and lipoxygenase (LOX, EC 1.13.11.12) activity significantly increased in the chloroplasts of maize exposed to Ni stress, revealing an oxidative damage occurred in maize chloroplasts, whereas, the values of these parameters were markedly lowered in the SA-treated plants under Ni stress. Application of SA significantly enhanced the activities of superoxide dismutase (SOD, EC 1.15.1.1), ascorbate peroxidase (APX, EC 1.11.1.11), monodehydroascorbate reductase (MDHAR, EC 1.6.5.4), dehydroascorbate reductase (DHAR, EC 1.8.5.1) and glutathione reductase (GR, EC 1.6.4.2), and the poll of reduced ascorbate and glutathione in chloroplasts of the Ni-stressed maize. Accordingly, the fact that SA up-regulates the capacity of antioxidant defense system in chloroplasts, thus reducing the oxidative damage, is involved in the SA-induced alleviation of Ni toxicity in maize.
...
PMID:Up-regulation of chloroplastic antioxidant capacity is involved in alleviation of nickel toxicity of Zea mays L. by exogenous salicylic acid. 1937 98

Removal of reproductive 'sink' i.e. spikelets from wheat at anthesis delays the rate of flag leaf senescence. In this work, the antioxidant defense was studied in the flag leaf of Triticum aestivum cv. Kalyansona plants showing normal (S + plants) and delayed senescence via removal of spikelets (S- plants). This was done by measurement of metabolites and activities of enzymes such as superoxide dismutase, catalase, guaiacol peroxidase, ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase and glutathione reductase. S- plants had higher reduced glutathione/oxidized glutathione (GSH/GSSG) ratio and antioxidant enzyme activities than the control plants and the differences were apparent from 21 days after anthesis (DAA). The removal of the reproductive sink led to an increased antioxidant defense which may be contributing towards the delayed flag leaf senescence in wheat. Chloroplasts and mitochondria, important sources of ROS, were isolated at two stages representing early (7 DAA) and late (21 DAA) senescence. Oxidative damage to proteins was studied in these organelles in relation to SOD and APX. Mitochondria had higher levels of damaged proteins than chloroplasts at 7 DAA in both S+ and S- plants. Higher damage was related to the lower antioxidant enzyme levels of SOD and APX in mitochondria as compared to chloroplasts.
...
PMID:Delayed wheat flag leaf senescence due to removal of spikelets is associated with increased activities of leaf antioxidant enzymes, reduced glutathione/oxidized glutathione ratio and oxidative damage to mitochondrial proteins. 1939 42

Lettuce plants were grown at low (LL), middle (ML), and high light (HL) conditions to examine the relationship between photoacclimatory plasticity, light energy utilization, and antioxidant capacity. With the increase in light intensity from LL to ML, the energy flux via DeltapH- and xanthophylls-regulated thermal dissipation, fluorescence and constitutive thermal dissipation, and electron transport for photorespiratory carbon oxidation all increased significantly. However, plants at HL exhibited reduced electron transport for photosynthetic carbon reduction and decreased maximal photochemical efficiency of photosytem II (PSII) as compared to that at ML. Increasing light level significantly increased the alternative electron transport, O(2)(*-) production rate, and H(2)O(2) and malondialdehyde (MDA) contents followed by increased ferric reducing antioxidant power (FRAP) and activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), and glutathione reductase (GR). Moreover, plants exposed to HL showed higher nutritional value as indicated by the high contents of ascorbate, glutathione, carotenoids, and alpha-tocopherol. It was concluded that absorption of excess photon energy at high light was associated with increased antioxidant capacity and that produce quality could be improved by short-term exposure to suboptimum irradiance.
...
PMID:Impact of light variation on development of photoprotection, antioxidants, and nutritional value in Lactuca sativa L. 1943 54

Plant homeobox genes play an important role in plant development, including embryogenesis. Recently, the function of a class I homeobox of knox 3 gene, HBK3, has been characterized in the conifer Picea abies (L.) Karst (Norway spruce) [8]. During somatic embryogenesis, expression of HBK3 is required for the proper differentiation of proembryogenic masses into somatic embryos. This transition, fundamental for the overall embryogenic process, is accelerated in sense lines over-expressing HBK3 (HBK3-S) but precluded in antisense lines (HBK3-AS) where the expression of this gene is experimentally reduced. Altered HBK3 expression resulted in major changes of ascorbate and glutathione metabolism. During the initial phases of embryogeny the level of reduced GSH was higher in the HBK3-S lines compared to their control counterpart. An opposite profile was observed for the HBK3-AS lines where the glutathione redox state, i.e. GSH/GSH + GSSG, switched towards its oxidized form, i.e. GSSG. Very similar metabolic fluctuations were also measured for ascorbate, especially during the transition of proembryogenic masses into somatic embryos (7 days into hormone-free medium). At this stage the level of reduced ascorbate (ASC) in the HBK3-AS lines was about 75% lower compare to the untransformed line causing a switch of the ascorbate redox state, i.e. ASC/ASC + DHA + AFR, towards its oxidized forms, i.e. DHA + AFR. Changes in activities of several ascorbate and glutathione redox enzymes, including dehydroascorbate reductase (EC 1.8.5.1), ascorbate free radical reductase (EC 1.6.5.4) and glutathione reductase (GR; EC 1.6.4.2) were responsible for these metabolic differences. Data presented here suggest that HBK3 expression might regulate somatic embryo yield through alterations in glutathione and ascorbate metabolism, which have been previously implicated in controlling embryo development and maturation both in vivo and in vitro.
...
PMID:Altered HBK3 expression affects glutathione and ascorbate metabolism during the early phases of Norway spruce (Picea abies) somatic embryogenesis. 1957 Jun 87

The effect of different cadmium (Cd) concentrations (5, 50 and 500 microM) on growth, Cd accumulation and antioxidative systems was studied in Paxillus involutus, grown in liquid medium. Cd was rapidly accumulated by P. involutus and resulted in growth inhibition within 24 h. Antioxidative enzymes (superoxide dismutase (SOD), EC 1.15.1.1; catalase (CAT), EC 1.11.1.6; monodehydroascorbate radical reductase (MDAR), EC 1.6.5.4; dehydroascorbate reductase (DAR) glutathione reductase (GR), EC 1.8.1.7 and glutathione-dependent peroxidase (GPx), EC 1.11.1.9) were active in the investigated fungus. Furthermore, high concentrations of glutathione but no ascorbate were detected. Cd exposure resulted in a significant induction of SOD activity. However, activities of enzymes responsible for the detoxification of H2O2 showed no Cd-dependent increase or were only transiently induced (CAT, GPx) and no accumulation of H2O2 was detected. Exposure to low Cd concentrations (5 and 50 microM) caused an increase in GR, while 500 microM Cd led to an inhibition of GR and CAT. Increased glutathione concentrations were observed as a consequence of all Cd treatments. These results suggest that the antioxidative protection of the investigated strain of P. involutus was sufficient to avoid Cd-mediated oxidative stress. It is likely that this strain was able to detoxify high concentrations of Cd by transport of Cd into the vacuole because a high correlation between Cd and sulphur in the vacuole was detected by EDX.
...
PMID:Characterisation of antioxidative systems in the ectomycorrhiza-building basidiomycete Paxillus involutus (Bartsch) Fr. and its reaction to cadmium. 1970 95

Plants have evolved mechanisms to avoid and repair UV radiation damage, and the free radicals caused by UV tend to be involved in the induction of antioxidant defense systems. In this study, changes in resveratrol and antioxidant enzymes were investigated in relation to UV damage in peanut seedlings. Accumulation of endogenous resveratrol and stilbene synthase mRNA occurred rapidly and significantly in response to UV-C irradiation. Applying resveratrol before UV-C irradiation mitigated rusty spots and wilting of peanut leaves, and inhibition of resveratrol by applying 3,4-methylenedioxycinnamic acid worsened UV-C damage, an effect that was found to be concentration dependent. Correspondingly, the effect of resveratrol on malondialdehyde was similar to changes in the apparent morphology of seedling leaves. Changes in H(2)O(2), O(2)(-), and antioxidant enzymes showed some similarities after either UV-C irradiation or resveratrol treatment. Activities of superoxide dismutases, glutathione reductase, and catalase were more than 2-fold higher during the first 1h after treatments. Ascorbate peroxidase activity increased to more than 3-fold higher 24h after irradiation, whereas it was more than 2-fold higher 8h after resveratrol treatment. Activities of dehydroascorbate reductase and monodehydroascorbate reductase increased by 40% during 8-24h after treatments. Consequently, we proposed that changes in endogenous resveratrol and in antioxidant enzymes may have been involved in oxidative stress induced by UV-C exposure in peanut seedlings.
...
PMID:Changes of resveratrol and antioxidant enzymes during UV-induced plant defense response in peanut seedlings. 1971 23


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---