Peroxidation Of Unsaturated Fatty Acids Research Articles

Peroxidation of unsaturated fatty acids is associated with poor storability in onion seed

Peroxidation of unsaturated fatty acids is associated with poor storability in onion seed

Inhibitory effect of tannic acid on the growth of Apiospora arundinis and 3-Nitropropionic acid production.

This study aimed to investigate the inhibitory effect of tannic acid (TA) on the growth of Apiospora arundinis and 3-Nitropropionic acid (3-NPA) production. To investigate the antifungal mechanism, the effects of TA on the hypha growth, electrical conductivity, hypha morphology, defense-related enzymes, and 3-NPA production of A. arundinis were studied. TA concentrations of 640 and 1280 μg ml-1 exhibited strong antifungal activity against A. arundinis. The results of scanning electron microscopy and transmission electron microscopy showed that the hypha of the A. arundinis was severely deformed after TA treatment, and the cell membrane was blurred and thin, vacuoles were obviously shrunken and smaller, and most of the organelles were decomposed into irregular fragments. The increased electrical conductivity and malondialdehyde content indicated that TA caused peroxidation of unsaturated fatty acids and damaged the structure of the cell membrane. The decrease of intracellular ATPase and succinate dehydrogenase content indicated that TA damaged the function of mitochondria, and participated in the inhibition of respiratory metabolism. In addition, TA significantly reduced 3-NPA production and completely inhibited 3-NPA production at 640 and 1280 μg ml-1. TA effectively inhibited both growth of A. arundinis in vitro and 3-NPA production.

From linoleic acid to hexanal and hexanol by whole cell catalysis with a lipoxygenase, hydroperoxide lyase and reductase cascade in Komagataella phaffii.

Green leaf volatiles (GLVs) cover a group of mainly C6-and C9-aldehydes, -alcohols and -esters. Their name refers to their characteristic herbal and fruity scent, which is similar to that of freshly cut grass or vegetables. Lipoxygenases (LOXs) catalyze the peroxidation of unsaturated fatty acids. The resulting hydroperoxy fatty acids are then cleaved into aldehydes and oxo acids by fatty acid hydroperoxide lyases (HPLs). Herein, we equipped the yeast Komagataella phaffii with recombinant genes coding for LOX and HPL, to serve as a biocatalyst for GLV production. We expressed the well-known 13S-specific LOX gene from Pleurotus sapidus and a compatible HPL gene from Medicago truncatula. In bioconversions, glycerol induced strains formed 12.9mM hexanal using whole cells, and 8mM hexanol was produced with whole cells induced by methanol. We applied various inducible and constitutive promoters in bidirectional systems to influence the final ratio of LOX and HPL proteins. By implementing these recombinant enzymes in Komagataella phaffii, challenges such as biocatalyst supply and lack of product specificity can finally be overcome.

Improving the catalytic efficiency of Pseudomonas aeruginosa lipoxygenase by semi-rational design

Lipoxygenase (LOX) catalyzes the peroxidation of unsaturated fatty acids to produce hydroperoxides, which had been widely used in food, medicine and chemical industries due to its decoloration of food and conversion of renewable oils. Thus, higher catalytic activity and stability is desired for low-cost and expanded industrial applications of LOX. To improve the catalytic activity of LOX, a mutant library of Pseudomonas aeruginosa lipoxygenase (PaLOX) was firstly built via semi-rational design. The kcat/Km of mutant increased by 9.2-fold and the half-life (t1/2) at 50 °C increased by 4.6 min. Molecular dynamics (MD) simulation indicated that mutation reduced steric hindrance to substrate binding and increased the flexibility of the lid domain that covered the bound unsaturated fatty acid substrate. In addition, van der Waals interactions between the substrate and amino acid residues of the binding pocket increased and alkyl and Pi-alkyl interactions decreased, which might improve the flexibility and substrate binding affinity. These findings promoted understanding of the structure-function relationship of LOX and increase its catalytic efficiency and stability for further industrial application.

Lipid Peroxidation Produces a Diverse Mixture of Saturated and Unsaturated Aldehydes in Exhaled Breath That Can Serve as Biomarkers of Lung Cancer-A Review.

The peroxidation of unsaturated fatty acids is a widely recognized metabolic process that creates a complex mixture of volatile organic compounds including aldehydes. Elevated levels of reactive oxygen species in cancer cells promote random lipid peroxidation, which leads to a variety of aldehydes. In the case of lung cancer, many of these volatile aldehydes are exhaled and are of interest as potential markers of the disease. Relevant studies reporting aldehydes in the exhaled breath of lung cancer patients were collected for this review by searching the PubMed and SciFindern databases until 25 May 2022. Information on breath test results, including the biomarker collection, preconcentration, and quantification methods, was extracted and tabulated. Overall, 44 studies were included spanning a period of 34 years. The data show that, as a class, aldehydes are significantly elevated in the breath of lung cancer patients at all stages of the disease relative to healthy control subjects. The type of aldehyde detected and/or deemed to be a biomarker is highly dependent on the method of exhaled breath sampling and analysis. Unsaturated aldehydes, detected primarily when derivatized during preconcentration, are underrepresented as biomarkers given that they are also likely products of lipid peroxidation. Pentanal, hexanal, and heptanal were the most reported aldehydes in studies of exhaled breath from lung cancer patients.

Determination of toxic effects of deltamethrin on the primary gill cell culture of Lake Van fish [Alburnus tarichi (Güldenstadt 1814)

Lake Van fish is one of few vertebrate species living in the lake, therefore it plays a very useful role as an indicator in determining lake pollution. Deltamethrin (DLT) is one of the pesticides used extensively in the Lake Van basin. In this study, it was aimed to determine the effects of DLT on the primary gill cell culture. Different concentrations of DLT (0.01, 0.1, 1, and 10 µM) were added to primary gill cell culture and the total antioxidant and oxidant levels, malondialdehyde (MDA), and 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels were determined at the end of 24 and 48 h of administration. While the highest concentration of applied DLT (10 µM) caused a significant increase in the total oxidant level at 48 h, a decrease in the total antioxidant level was detected at 24 and 48 h (P < 0.05). The increase in MDA level, which is the product of lipid peroxidation of unsaturated fatty acids, with DLT concentrations of 1–10 µM at the end of 24 and 48 h was found to be significant (P < 0.05). As a result, it can be said that DLT caused oxidative stress in the primary gill cell culture of Lake Van fish exposed to concentrations of 1 and 10 µM, but no genotoxic effect was observed.

Role of Edaravone as a Treatment Option for Patients with Amyotrophic Lateral Sclerosis.

Amyotrophic Lateral Sclerosis (ALS), also known as Lou Gehrig’s disease, is a progressive and fatal neurodegenerative disease that leads to a loss of muscle control due to nerve cells being affected in the brain and spinal cord. Some of the common clinical presentations of ALS include weakness of muscles, changes in behavior, dysfunction in speech, and cognitive difficulties. The cause of ALS is uncertain, but through several studies, it is known that mutations in SOD1 or C9orf72 genes could play a role as a factor of ALS. In addition, studies indicate that an excessive amount of free radicals, the reactive oxygen species (ROS), leads to neuronal damage by the peroxidation of unsaturated fatty acids in the neuronal cells. Edaravone, the newly approved antioxidant drug for ALS, halts the progression of ALS in the early stages through its cytoprotective effect and protects the nerves by reducing ROS. In this review, different aspects of ALS will be discussed, including its pathology, genetic aspect, and diagnosis. This review also focuses on edaravone as a treatment option for ALS, its mechanism of action, and its pharmacological properties. Clinical trials and adverse effects of edaravone and care for ALS patient are also discussed.

Secretion of Pseudomonas aeruginosa Lipoxygenase by Pichia pastoris upon Glycerol Feed.

Pseudomonas aeruginosa lipoxygenase (PaLOX) catalyzes the peroxidation of unsaturated fatty acids. Not only linoleic acid, but also linolenic acid and oleic acid are oxidized. The natural host secretes PaLOX into the periplasmic space. Herein, the aim is to secrete PaLOX to the culture supernatant of Pichia pastoris. Since protein background in the culture supernatant is typically rather low, this strategy allows for almost pure production of PaLOX applicable for the valorization of renewable fatty acids, for example for the production of green leaf volatiles. Using the CAT1 promoter system and the well-established α-factor signal sequence for secretion, methanol- and glycerol-induced secretion are compared and the latter shows four times more LOX activity in the culture supernatant under methanol-free conditions. In addition, secreted PaLOX is purified and the specific activity with enzyme in culture supernatant is compared. Notably, the predominant specific activity is achieved for enzyme in culture supernatant - 11.6 U mg-1 - reaching five times higher specific activity than purified PaLOX.

Content of natural antioxidants depending on typological features of autonomous regulation in chickens

Secondary antioxidants inhibit the development of chain reactions of peroxidation of unsaturated fatty acids. In turn, the autonomous nervous system regulates the functioning of internal organs and affects the intensity of metabolic processes in the animal body. However, the question of the content of natural antioxidants in birds, depending on the typological features of autonomous regulation, is not well understood. The purpose of the work was to research the content of natural antioxidants depending on the typological features of the tone of the autonomic nervous system in chickens. For research, chickens of the 35-day-old Cobb-500 cross were used. A study of the typological features of autonomous tone in a research bird was carried out by recording an electrocardiogram and counting one hundred R-R cardio intervals, which were processed by the method of variational pulsometry according to R. M. Baevsky. To determine the effect of autonomic nervous regulation types on the activity of secondary antioxidants in experimental birds, blood samples were taken and the content of tocopherol and retinol was determined. As a result of the researches, it was found that the content of tocopherol and retinol in vagotonic chickens of 35 days old was significantly higher by 13.4 % (P &lt; 0.001) and 14.06 % (P &lt; 0.01) than in sympathotonic chickens, respectively. Reliable correlations between the increase in tocopherol activity and the level of retinol in chickens with a sympathotonic type of autonomic nervous system were revealed. Determination of the content of natural antioxidants of chickens depending on the types of the atomic nervous system makes it possible to identify the bird with the highest stress resistance and antioxidant protection. This creates the conditions for the distribution of chickens depending on typological characteristics and makes it possible to identify chickens at an early stage of development; they need more vitamin supplements with antioxidant properties, as well as to prevent a decrease in growth due to the formation of oxidative stress during the entire growing period.

Lipoxygenase Inhibition Activity of Coumarin Derivatives-QSAR and Molecular Docking Study.

Lipoxygenases (LOXs) are a family of enzymes found in plants, mammals, and microorganisms. In animals and plants, the enzyme has the capability for the peroxidation of unsaturated fatty acids. Although LOXs participate in the plant defense system, the enzyme’s metabolites can have numerous negative effects on human health. Therefore, many types of research are searching for compounds that can inhibit LOXs. The best quantitative structure–activity relationship (QSAR) model was obtained using a Genetic Algorithm (GA). Molecular docking was performed with iGEMDOCK. The inhibition of lipoxygenase was in the range of 7.1 to 96.6%, and the inhibition of lipid peroxidation was 7.0–91.0%. Among the synthesized compounds, the strongest inhibitor of soybean LOX-3 (96.6%) was found to be 3-benzoyl-7-(benzyloxy)-2H-chromen-2-one. A lipid peroxidation inhibition of 91.0% was achieved with ethyl 7-methoxy-2-oxo-2H-chromene-3-carboxylate. The docking scores for the soybean LOX-3 and human 5-LOX also indicated that this compound has the best affinity for these LOX enzymes. The best multiple linear QSAR model contains the atom-centered fragment descriptors C-06, RDF035p, and HATS8p. QSAR and molecular docking studies elucidated the structural features important for the enhanced inhibitory activity of the most active compounds, such as the presence of the benzoyl ring at the 3-position of coumarin’s core. Compounds with benzoyl substituents are promising candidates as potent lipoxygenase inhibitors.

Recombinant Lipoxygenases and Hydroperoxide Lyases for the Synthesis of Green Leaf Volatiles.

Green leaf volatiles (GLVs) are mainly C6- and in rare cases also C9-aldehydes, -alcohols, and -esters, which are released by plants in response to biotic or abiotic stresses. These compounds are named for their characteristic smell reminiscent of freshly mowed grass. This review focuses on GLVs and the two major pathway enzymes responsible for their formation: lipoxygenases (LOXs) and fatty acid hydroperoxide lyases (HPLs). LOXs catalyze the peroxidation of unsaturated fatty acids, such as linoleic and α-linolenic acids. Hydroperoxy fatty acids are further converted by HPLs into aldehydes and oxo-acids. In many industrial applications, plant extracts have been used as LOX and HPL sources. However, these processes are limited by low enzyme concentration, stability, and specificity. Alternatively, recombinant enzymes can be used as biocatalysts for GLV synthesis. The increasing number of well-characterized enzymes efficiently expressed by microbial hosts will foster the development of innovative biocatalytic processes for GLV production.

Special aspects of systemic inflammation course in animals.

Aim:In this study, we identified characteristics of systemic inflammation associated with surgical sepsis in animals. We evaluated the role of purine metabolism, functionally associated lipoperoxidation processes of membrane structures, and the antioxidant system in the development of surgical sepsis in dogs.Materials and Methods:Dogs with a provisional exclusion of sepsis were included in the study. The control group (Group 1) included clinically healthy dogs (n=5), and medium-breed dogs with systemic inflammation response syndrome (n=30) were categorized in the experimental group (Group 2). Along with hemogram and biochemical analysis, we determined the amount of malondialdehyde, glutathione, superoxide dismutase, catalase, glutathione reductase, and glucose-6-phosphate dehydrogenase on the 1st and 14th day of the study. Treatment included a thorough reorganization of the septic focus, followed by antibacterial therapy. Sick animals were injected with a drug (dexamethasone) that suppresses the synthesis and inhibits the action of inflammatory mediators. Decompensation of the functions of organs and systems was carried out using symptomatic therapy.Results:We found that enhanced lipid peroxidation of unsaturated fatty acids of membrane structures stimulates the generalization of inflammatory process, as evidenced by the significant deviation from the physiologically normal values of lipid peroxidation, C-reactive protein, blood cell count, etc. The course of systemic inflammation associated with surgical sepsis in animals can be attributed to several consistently developing processes that function as a result of increased purine mononucleotide catabolism, peroxide compound formation, and their excessive breakdown in reactions associated with the consumption of glutathione due to the insufficient recovery of glutathione disulfide.Conclusion:The amount of uric acid, glycosaminoglycans, hyaluronic acid in blood plasma, and the content of malondialdehyde, glutathione, and glutathione reductase in erythrocytes should be considered when assessing the severity of the systemic inflammatory process. The increased glutathione requirement in dogs with surgical sepsis requires intervention with pharmacological agents, and further research is needed in this aspect.

Salicylic acid as an effective elicitor for improved taxol production in endophytic fungus Pestalotiopsis microspora.

Salicylic acid (SA) is an effective elicitor to increase taxol production in Pestalotiopsis microspora. Addition of SA at the concentration of 300 μM yielded taxol 625.47 μg L-1, 45- fold higher than that of the control. Elicitation of the role of SA in the fungal taxol biosynthetic pathway revealed that SA enhanced reactive oxygen species and lipid peroxidation of unsaturated fatty acids of P. microspora mycelia. This oxidative process stimulates isoprene biosynthetic pathway by triggering expression of the geranylgeranyl pyrophosphate synthase gene leading to improved biosynthesis of taxol in P. microspora.

8 - Supplementation with omega-3 fatty acids potentiates glutathione oxidation in human airway epithelial cells exposed to ozone

The health benefits of dietary fish oil consumption have been widely reported. Eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids, two omega-3 fatty acids found in fish oil, have been associated with anti-inflammatory and pro-resolving effects through their metabolism to specialized pro-resolving mediators (SPMs) and displacement of arachidonic acid (AA). However, the 5 and 6 double bonds in EPA and DHA respectively are targets for lipid peroxidation by ozone (O3), a major photochemical pollutant to which millions of Americans are exposed. Products of unsaturated fatty acid peroxidation by O3 have been proposed to mediate functional and inflammatory effects of O3 exposure. Thus, cellular supplementation with omega-3s has the potential to both promote and help resolve inflammation during O3 exposure. To investigate this paradox, we supplemented 16-HBE human airway epithelial cells (HAEC) expressing the fluorogenic glutathione redox potential (EGSH) sensor roGFP overnight with EPA, DHA, the monounsaturated fatty acid oleic acid (OA), or the saturated fatty acid stearic acid (SA). Alterations in EGSH were monitored in real time using live-cell microscopy during exposure to O3. We found that supplementation with EPA and DHA, but not OA or SA, caused a marked potentiation of the O3-induced increases in EGSH, evident as both an accelerated response time and increase in the magnitude of response. Notably, the potentiation of GSH oxidation occurred at O3 concentrations as low as 0.08 ppm, the current National Ambient Air Quality Standard level. These results suggest that membrane fatty acid saturation is a determinant of the oxidative responses to O3 in HAEC. These findings may have implications for dietary recommendations for populations exposed to O3. This abstract does not necessarily reflect EPA policy.

Antifungal Activity and Action Mechanism of Ginger Oleoresin Against Pestalotiopsis microspora Isolated From Chinese Olive Fruits

Pestalotiopsis microspora (P. microspora) is one of dominant pathogenic fungi causing rotten disease in harvested Chinese olive (Canarium album Lour.) fruits. The purposes of this study were to evaluate the antifungal activities of ginger oleoresin (GO) against P. microspora and to illuminate the underlying action mechanisms. The in vitro assays indicate that GO exhibited strong antifungal activity against mycelial growth of P. microspore, and with 50%-inhibition concentration (EC50) and 90%-inhibition concentration (EC90) at 2.04 μL GO and 8.87 μL GO per mL propylene glycol, respectively, while the minimal inhibitory concentration (MIC) and minimal fungicidal concentration were at 10 μL GO and 30 μL GO per mL propylene glycol, respectively. Spore germination of P. microspora was inhibited by GO in a dose-dependent manner, and with 100% inhibition rate at the concentration of 8 μL GO per mL propylene glycol. Compared to the control, the cellular membrane permeability of P. microspora increased due to severe leakage of intercellular electrolytes, soluble proteins, and total sugars with the treatments (EC50, EC90) by GO during incubation. In addition, analysis of fatty acid contents and compositions in cellular membrane by GC-MS indicated that GO could significantly promote the degradation or peroxidation of unsaturated fatty acids in P. microspore, resulting in the enhancement of membrane fluidity. Moreover, observations of microstructure further showed the damage to plasma membrane and morphology of P. microspora caused by GO, which resulted in distortion, sunken and shriveled spores and mycelia of the pathogen. Furthermore, in vivo assay confirmed that over 3 MIC GO treatments remarkably suppressed disease development in P. microspore inoculated-Chinese olive fruit. These results demonstrate that owing to its strong antifungal activity, GO can be used as a promising antifungal agent to inhibit the growth of pathogenic fungi in Chinese olives.

Design and synthesis of new esters of terpenoid alcohols as 15-lipoxygenase inhibitors.

Objective(s):15-Lipoxygenases are one of the iron-containing proteins capable of performing peroxidation of unsaturated fatty acids in animals and plants. The critical role of enzymes in the formation of inflammations, sensitivities, and some cancers has been demonstrated in mammals. The importance of enzymes has led to the development of mechanistic studies, product analysis, and synthesis of inhibitors. Materials and Methods:The inhibitory activity of all synthetic compounds against SLO (soybean 15-lipoxygenase: L1; EC 1,13,11,12) was determined using the peroxide formation method. In this method, the basis of evaluation of lipoxygenase activity is measuring the concentration of fatty acid peroxide. All measurements were compared with 4-​methyl-​2-​(4-​methylpiperazinyl)pyrimido[4,​5-​b]benzothiazine (4-MMPB) as one of the known lipoxygenase inhibitors. The radical scavenging ability of all synthetic compounds using stable free radicals (DPPH: 2,2-diphenyl-1-picrylhydrazyl) was measured for further investigation.Results: In this study, a series of esters from phenolic acids with terpenoid alcohols was synthesized and their inhibitory potency against soybean 15-lipoxygenase and their free radical scavenging properties were determined. Among the synthetic compounds, adamantyl protocatetuate 2j and bornyl protocatetuate 2o showed the most potent inhibitory activity with IC50 values of 0.95 and 0.78 μm, respectively.Conclusion:By changing the alcohol and acyl portions of stylosin, it was found that electronic properties play main role in lipoxygenase inhibition potency in contrast with steric features. Insertion of more reductive phenolic moiety such as catechuate and gallate lead to more lipoxygenase inhibition potency of the esters as observed in their radical scavenging activity.

Hens ranked as highly feed efficient have an improved albumen quality profile and increased polyunsaturated fatty acids in the yolk1

The shelf life of eggs that contain elevated levels of polyunsaturated fatty acids (PUFA) is compromised due to the relative instability and therefore greater potential for lipid peroxidation of unsaturated fatty acids (FA). Poultry that is highly feed efficiency (HFE) exhibits higher systemic levels of antioxidant enzymes and therefore may produce eggs with improved albumen quality and favorable FA profiles that are stable over time. We tested the hypothesis that HFE-laying hens produce eggs with improved internal egg quality and a favorable yolk FA profile prior to and following storage. Following an initial screening phase (7 wk) using 140 Isa Brown layers (28 wk old), the 10 most efficient (FCR < 1.99 ± 0.05) and the 10 least efficient (FCR > 2.30 ± 0.05) hens were identified and designated as HFE and low feed efficiency (LFE) groups, respectively. Internal quality and composition were determined on eggs (n = 10 per group) stored at 15 °C for 0, 14, and 28 d. At 0, 14, and 28 d, the albumen weight, albumen height, Haugh unit (HU), and albumen:yolk ratio of eggs from the HFE group were significantly higher (P < 0.01), whereas the eggs from the LFE group had heavier (P < 0.01) yolk than the HFE group. After 28-d storage, the yolk color score of the LFE group was lower (paler; P < 0.05) compared with that of the HFE group. The relative proportions of total PUFA and the ratio of total PUFA and total saturated fatty acids (SFA) were higher (P < 0.05) in HFE group of eggs. The LFE group of eggs contained higher (P < 0.05) levels of lipid peroxidation marker (thiobarbituric acid reactive substances; TBARS) values both in fresh and in stored eggs. The results suggest that HFE hens produce eggs with greater albumen quality and higher levels of yolk PUFA both at lay and after storage.

2-Prenylated m-dimethoxybenzenes as potent inhibitors of 15-lipo-oxygenase: inhibitory mechanism and SAR studies.

15-lipo-oxygenases are one of the iron-containing proteins capable of performing peroxidation of unsaturated fatty acids in animals and plants. The critical role of enzymes in the formation of inflammations, sensitivities, and some cancers has been demonstrated in mammals. The importance of enzymes has led to the development of mechanistic studies, product analysis, and synthesis of inhibitors. In this study, a series of allyl and prenyl dimethoxybenzenes were synthesized and their inhibitory potency against soybean 15-Lipo-oxygenase (L1; EC 1,13,11,12) was determined. Among the synthetic compounds, 2,6-dimethoxy-1-isopentenyl-4-methylbenzene, 2,6-dimethoxy-1-geranyl-4-methylbenzene, and 2,6-dimethoxy-1-farnesyl-4-methylbenzene showed the most potent inhibitory activity with IC50 values of 7.6, 5.3, and 0.52μm, respectively. For some of the compounds, SAR studies showed acceptable relationship between inhibitory potency and enzyme-ligand interactions. Radical scavenging assessment results apart from the SAR studies indicate that electronic properties are the major factors for lipo-oxygenase inhibition potency of the mentioned compounds. Based on the theoretical studies, it was suggested that CH…O intramolecular hydrogen bond between ortho-methoxy oxygen and methine hydrogen atoms is one of the major factors in the stability of 2,6-dimethoxyallyl(or prenyl)benzenes radical via the planarity fixation between phenyl and allyl (or prenyl) pi orbitals.

Oxidative Stress in Plants Under Drought Conditions and the Role of Different Enzymes

The effects of drought stresses on plant metabolism are either direct or secondary. Oxidative stress is induced by a wide range of biotic and abiotic stresses including UV-light, pathogen invasion (hypersensitive reaction), herbicide action, oxygen shortage, among others. Drought and salt stresses usually lead to the production of reacting oxygen species (ROS) such as hydrogen peroxide (H2O2) and superoxide (O2 ·–), both produced in a number of cellular reactions, including the iron-catalysed Fenton reaction, and by various enzymes such as lipoxygenases, peroxidases, NADPH oxidase and xanthine oxidase. To control the level of ROS under stress conditions, plant tissues contain a series of enzyme scavengers of ROS. The main cellular components susceptible to damage by free radicals are lipids (peroxidation of unsaturated fatty acids in membranes), proteins and enzymes (denaturation), carbohydrates and nucleic acids. Plant carbon balance during a period of salt/water stress and subsequent recovery may depend as much on the speed and degree of photosynthetic recovery, as it depends on the degree and speed of photosynthesis decline during water reduction. Current knowledge about physiological limitations to photosynthetic recovery after different intensities of water and salt stress is still scarce. From the large amount of data available on transcript-profiling studies in plants subjected to drought it is becoming apparent that plants perceive and respond to these stresses by quickly altering gene expression in parallel with physiological and biochemical alterations; this occurs even under mild to moderate stress conditions. From a recent comprehensive study that compared salt and drought stress it is apparent that both stresses led to down-regulation of some photosynthetic genes, with most of the changes being small possibly reflecting the mild stress imposed. Drought and salt stresses are significant challenges for mankind. The utilization of different strategies, namely genetic and enzyme engineering, can contribute to the alleviation of the associated oxidative stresses. Regulating the expression of genes encoding for specific proteins and enzymes can result into drought and salt tolerance. Different crop genotypes, such as sugarcane, soybean, and wheat have already been engineered for drought tolerance. Wheat genotypes showed alterations in antioxidant enzymes as well as in enzymes associated with carbon metabolism. These important strategies will be a vitally important tool in the quest to alleviate the earth’s future problems concerning food, energy, and the environment. The present review focus on oxidative stresses associated with drought and salt conditions addressing the metabolomics involved in such constraints.

Visible Light-Induced Lipid Peroxidation of Unsaturated Fatty Acids in the Retina and the Inhibitory Effects of Blueberry Polyphenols

The lipid peroxidation of unsaturated fatty acids (UFAs) in the retina not only threatens visual cells but also affects the physiological health of the retina. In this work, the potential damages caused by daily visible light exposure on retinal UFAs were evaluated via a simulated in vitro model. At the same time, the benefits of dietary supplementation of blueberries to the eyes were also assessed. After prolonged light exposure, lipid peroxidation occurred for both docosahexaenoic and arachidonic acids (DHA and AA, respectively). The oxidized UFAs presented obvious cytotoxicity and significantly inhibited cell growth in retinal pigment epithelium cells. Among the different blueberry polyphenol fractions, the flavonoid-rich fraction, in which quercetin was discovered as the main component, was considerably better in preventing visible light-induced DHA lipid peroxidation than the anthocyanin- and phenolic acid-rich fractions. Then the retinal protective activity of blueberry polyphenols against light-induced retinal injury was confirmed in vivo. On the basis of the above results, inhibiting lipid peroxidation of UFAs in the retina is proposed to be another important function mechanism for antioxidants to nourish eyes.