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Abdelgawad H.,University of Antwerp | Abdelgawad H.,University of Beni Sueif | De Vos D.,University of Antwerp | Zinta G.,University of Antwerp | And 4 more authors.
New Phytologist | Year: 2015

Proline (Pro) is a versatile metabolite playing a role in the protection of plants against environmental stresses. To gain a deeper understanding of the regulation of Pro metabolism under predicted future climate conditions, including drought stress, elevated temperature and CO2, we combined measurements in contrasting grassland species (two grasses and two legumes) at multiple organisational levels, that is, metabolite concentrations, enzyme activities and gene expression. Drought stress (D) activates Pro biosynthesis and represses its catabolism, and elevated temperature (DT) further elevated its content. Elevated CO2 attenuated the DT effect on Pro accumulation. Computational pathway control analysis allowed a mechanistic understanding of the regulatory changes in Pro metabolism. This analysis indicates that the experimentally observed coregulation of multiple enzymes is more effective in modulating Pro concentrations than regulation of a single step. Pyrroline-5-carboxylate synthetase (P5CS) and pyrroline-5-carboxylate reductase (P5CR) play a central role in grasses (Lolium perenne, Poa pratensis), and arginase (ARG), ornithine aminotransferase (OAT) and P5CR play a central role in legumes (Medicago lupulina, Lotus corniculatus). Different strategies in the regulation of Pro concentrations under stress conditions were observed. In grasses the glutamate pathway is activated predominantly, and in the legumes the ornithine pathway, possibly related to differences in N-nutritional status. © 2015 New Phytologist Trust.

Pandey R.,Indian Agricultural Research Institute | Zinta G.,University of Antwerp | AbdElgawad H.,University of Antwerp | AbdElgawad H.,University of Beni Sueif | And 3 more authors.
Biotechnology Advances | Year: 2015

Atmospheric [CO2] has increased substantially in recent decades and will continue to do so, whereas the availability of phosphorus (P) is limited and unlikely to increase in the future. P is a non-renewable resource, and it is essential to every form of life. P is a key plant nutrient controlling the responsiveness of photosynthesis to [CO2]. Increases in [CO2] typically results in increased biomass through stimulation of net photosynthesis, and hence enhance the demand for P uptake. However, most soils contain low concentrations of available P. Therefore, low P is one of the major growth-limiting factors for plants in many agricultural and natural ecosystems. The adaptive responses of plants to [CO2] and P availability encompass alterations at morphological, physiological, biochemical and molecular levels. In general low P reduces growth, whereas high [CO2] enhances it particularly in C3 plants. Photosynthetic capacity is often enhanced under high [CO2] with sufficient P supply through modulation of enzyme activities involved in carbon fixation such as ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). However, high [CO2] with low P availability results in enhanced dry matter partitioning towards roots. Alterations in below-ground processes including root morphology, exudation and mycorrhizal association are influenced by [CO2] and P availability. Under high P availability, elevated [CO2] improves the uptake of P from soil. In contrast, under low P availability, high [CO2] mainly improves the efficiency with which plants produce biomass per unit P. At molecular level, the spatio-temporal regulation of genes involved in plant adaptation to low P and high [CO2] has been studied individually in various plant species. Genome-wide expression profiling of high [CO2] grown plants revealed hormonal regulation of biomass accumulation through complex transcriptional networks. Similarly, differential transcriptional regulatory networks are involved in P-limitation responses in plants. Analysis of expression patterns of some typical P-limitation induced genes under high [CO2] suggests that long-term exposure of plants to high [CO2] would have a tendency to stimulate similar transcriptional responses as observed under P-limitation. However, studies on the combined effect of high [CO2] and low P on gene expression are scarce. Such studies would provide insights into the development of P efficient crops in the context of anticipated increases in atmospheric [CO2]. © 2015 Elsevier Inc.

Abouzid S.F.,University of Beni Sueif | El-Bassuony A.A.,Beni Suef University | Nasib A.,University of Karachi | Khan S.,University of Karachi | And 2 more authors.
International Journal of Applied Research in Natural Products | Year: 2010

Root cultures of Withania coagulans (Solanaceae) were obtained from in vitro germinated sterile plantlets. The roots grew axenically in MS medium containing 0.25 mgL-1 indole-3-butyric acid and 30 gL-1 sucrose. A RP-HPLC method for the determination of withanolides in plant tissues was developed using a binary gradient solvent system comprising acetonitrile and water containing 0.1% (v/v) acetic acid. The method was validated according to ICH guidelines. The linearity was found to be in the range of 1.2-720 μLmL-1. The method described is simple, sensitive, accurate and reproducible. The developed method was applied for quantification of withanolides level in cultured roots of W. coagulans. The root cultures synthesized withanolides of which withaferin A was the major compound. The productivity of withaferin A in the threeweek-old cultured roots was 11.65 μgg-1. Withaferin A production showed consistent increase with root growth during the three weeks of culture period. Industrial relevance: Plant tissue culture can be a potential source for important secondary metabolites such as pharmaceuticals and food additives. This technology depends on using plant cultures in a similar manner to microbial fermentation for factory-type production of target metabolites. The technology bears many advantages over conventional agricultural methods: production is independent of variation in crop quality or failure, yield of target compounds would be constant and geared to demand, there is no difficulty in applying good manufacturing practice to the early stages of production, production would be possible anywhere under strictly controlled conditions, independency of political problems, free from risk of contamination with pesticides, herbicides, agrochemicals or fertilizers and new methods of production can be patented. © 2010 Healthy Synergies Publications.

Sinha A.K.,University of Antwerp | AbdElgawad H.,University of Antwerp | AbdElgawad H.,University of Beni Sueif | Zinta G.,University of Antwerp | And 5 more authors.
PLoS ONE | Year: 2015

Salinity fluctuation is one of the main factors affecting the overall fitness of marine fish. In addition, water borne ammonia may occur simultaneously with salinity stress. Additionally, under such stressful circumstances, fish may encounter food deprivation. The physiological and ion-osmo regulatory adaptive capacities to cope with all these stressors alone or in combination are extensively addressed in fish. To date, studies revealing the modulation of antioxidant potential as compensatory response to multiple stressors are rather lacking. Therefore, the present work evaluated the individual and combined effects of salinity challenge, ammonia toxicity and nutritional status on oxidative stress and antioxidant status in a marine teleost, European sea bass (Dicentrarchus labrax). Fish were acclimated to normal seawater (32 ppt), to brackish water (20 ppt and 10 ppt) and to hypo-saline water (2.5 ppt). Following acclimation to different salinities for two weeks, fish were exposed to high environmental ammonia (HEA, 20 mg/L representing 50% of 96h LC50 value for ammonia) for 12 h, 48 h, 84 h and 180 h, and were either fed (2% body weight) or fasted (unfed for 7 days prior to HEA exposure). Results show that in response to decreasing salinities, oxidative stress indices such as xanthine oxidase activity, levels of hydrogen peroxide (H2O2) and lipid peroxidation (malondialdehyde, MDA) increased in the hepatic tissue of fasted fish but remained unaffected in fed fish. HEA exposure at normal salinity (32 ppt) and at reduced salinities (20 ppt and 10 ppt) increased ammonia accumulation significantly (84 h-180 h) in both feeding regimes which was associated with an increment of H2O2 and MDA contents. Unlike in fasted fish, H2O2 and MDA levels in fed fish were restored to control levels (84 h-180 h); with a concomitant increase in superoxide dismutase (SOD), catalase (CAT), components of the glutathione redox cycle (reduced glutathione, glutathione peroxidase and glutathione reductase), ascorbate peroxidase (APX) activity and reduced ascorbate (ASC) content. On the contrary, fasted fish could not activate many of these protective systems and rely mainly on CAT and ASC dependent pathways as antioxidative sentinels. The present findings exemplify that in fed fish single factors and a combination of HEA exposure and reduced seawater salinities (upto 10 ppt) were insufficient to cause oxidative damage due to the highly competent antioxidant system compared to fasted fish. However, the impact of HEA exposure at a hypo-saline environment (2.5 ppt) also defied antioxidant defence system in fed fish, suggesting this combined factor is beyond the tolerance range for both feeding groups. Overall, our results indicate that the oxidative stress mediated by the experimental conditions were exacerbated during starvation, and also suggest that feed deprivation particularly at reduced seawater salinities can instigate fish more susceptible to ammonia toxicity. © 2015 Sinha et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Houssen M.E.,University of Beni Sueif | Ragab A.,Mansoura University | Mesbah A.,Mansoura University | El-Samanoudy A.Z.,Mansoura University | And 3 more authors.
Clinical Biochemistry | Year: 2010

ObjectiveTo assess the efficacy of a combination of Boswellia serrata, licorice root (Glycyrrhiza glabra) and Tumeric root (Curcuma longa) as natural leukotriene inhibitor, antiinflammatory and antioxidant products respectively in controlling bronchial asthma. Subjects and methodsThe study comprised 63 patients with bronchial asthma that are further subdivided into two groups .Group 1 receiving oral capsule (combined herb) in a soft-gelatin capsule 3 times daily for 4. weeks and group 2 receiving placebo.Plasma leukotriene C4 (LTC4), nitric oxide (NO) and malondialdehyde (MDA) levels were measured and pulmonary function was also assessed in all patients enrolled in the study. Results: There was a statistically significant decrease in the plasma levels of LTC4, (MDA), and NO in target therapy group when compared with placebo group. Conclusion: The used extract contained Boswellia serrata, Curcuma longa and Glycyrrhiza has a pronounced effect in the management of bronchial asthma. © 2010 The Canadian Society of Clinical Chemists.

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