TBARS Accumulation Research Articles

Photocatalytic films with high ethylene degradation efficiency for strawberry preservation

The preservation of fruits has always been a research hotspot. In this research, titanium dioxide(TiO2) exhibiting diffraction peaks characteristic of both anatase and rutile phases was synthesized. Subsequently, photocatalytic films loaded with the TiO2 were fabricated using a twin-screw extruder combined with an extrusion casting technique. The films demonstrated a highest ethylene photocatalytic degradation efficiency of 88.57 %. The addition of TiO2 significantly enhanced the hydrophilicity of the films, with a maximum increase of 8.08 %. The tensile strength and elongation at break of the films were also improved. The optical properties, barrier properties and mechanical properties revealed that the film may make contributions to slowing down light aging, reducing weight loss of strawberries and increasing the load-bearing property. Furthermore, fresh-keeping experiment proved that the photocatalytic films could markedly slow down the appearance change, reduce weight loss and TBARS accumulation while decelerating the decline of TSS and antioxidant capacity in strawberries.

Molecular and Biochemical Evidence of the Toxic Effects of Terbuthylazine and Malathion in Zebrafish

Our research sought to determine the molecular and biochemical effects of environmentally relevant exposure to commonly used chloro-s-triazine herbicide terbuthylazine and organophosphate insecticide malathion on zebrafish. To this aim, mature zebrafish were exposed to 2 and 30 µg L-1 terbuthylazine and 5 and 50 µg L-1 malathion alone and in combination for 14 days. Aside from the accumulation of TBARS and protein carbonyls, a decrease in antioxidants and succinate dehydrogenase activity, an increase in oxidized glutathione, and enhanced apoptosis via Caspase-3 and BAX overexpression were observed. Furthermore, terbuthylazine and malathion induced mitochondrial swelling (up to 210% after single exposure and up to 470% after co-exposure) and lactate dehydrogenase leakage (up to 268% after single exposure and up to 570% after co-exposure) in a concentration-dependent manner. Significant upregulation of ubiquitin expression and increased cathepsin D activity were characteristics that appeared only upon terbuthylazine exposure, whereas the induction of IgM was identified as the specific characteristic of malathion toxicity. Meanwhile, no alterations in the zebrafish hypothalamic-pituitary-thyroid axis was observed. Co-exposure increased the adverse effects of individual pesticides on zebrafish. This study should improve the understanding of the mechanisms of pesticide toxicity that lead to fish impairment and biodiversity decline.

Ex-foliar applied extremolyte ectoine improves water management, photosystem, antioxidant system and redox homeostasis in Zea mays under cadmium toxicity

Stress-protective osmolytes stabilize biomolecules and mediate plant defense responses, which help to remove the negative effects of stress in plants. However, the responses of ectoine (ECT, 1,4,5,6-tetrahydro-2-methyl-4-pyrimidinecarboxylic acid), as an osmolyte, need to be investigated for a better understanding of the defense pathways on water status, antioxidant system, and photosynthetic machinery against heavy metal stress. The different ECT concentrations (0.25–0.5 mM) were applied to Zea mays L. cv Karadeniz Yildizi with/without cadmium stress (100–200 μM Cd). Stress caused an inhibition in growth (RGR), water content (RWC), and osmotic potential (ΨΠ). After stress exposure, ECTs provided effective water management by elevating RGR, RWC and ΨΠ. The maize exposed to stress exhibited notable repression in the photosynthetic system depending on decreasing Fv/Fm, qP and, ΦPSII and increasing NPQ. The consumption of excess energy on photosynthetic machinery was controlled by ECTs via reversing these parameters. Cd toxicity resulted in downregulated-transcript levels of psbA, psbD, and psaB, which impaired the stability of PSI and PSII. After both Cd treatments, ECTs markedly induced the expression levels of psaA and psaB, which showed effective protection of photochemical activity. Cd-applied plants exhibited a decrease in superoxide dismutase (SOD), catalase (CAT), peroxidase (POX), ascorbate peroxidase (APX), glutathione peroxidase (GPX), and glutathione reductase (GR), causing the accumulation of TBARS in lipid peroxidation. Under Cd+ECTs, SOD, glutathione S-transferase (GST) and POX had effective radical scavenging, thereby maintaining low contents of H2O2 and TBARS. ECTs alleviated the low Cd treatment-impaired redox state and participated in the ascorbate (AsA) and glutathione (GSH) regeneration. Consequently, ECT-mediated tolerance of maize was proved by increased growth, water potential, antioxidant capacity (especially SOD, POX), up-regulation of genes encoding proteins related to PSI, and PSII and AsA-GSH redox systems under Cd toxicity.

Salinity induced redox metabolic shift influence hormonal profile and germination performance of two contrasting indica rice cultivars

The role of redox deviations under salinity on metabolic dysfunction associated with progression of seed germination is well documented. However, the correlative evaluation of the salinity induced changes in the redox system and hormonal profile in regulating germination are least studied and hence is the subject of present investigation. Imposition of post imbibitional salinity stress (PISS) to two contrasting rice genotypes differing in sensitivity towards salinity (Oryza sativa L., Cultivars Patnai and IR29) caused differential and significant redox-metabolic shift and germination performances. Biomarkers of oxidative stress like, accumulation of total ROS, in situ localization of hydrogen peroxide, radical scavenging property, and lipid peroxidation are assessed for the determination of salinity induced differential changes in redox status of both the experimental cultivars. Salt resistant cultivar Patnai exhibiting better redox regulatory property under PISS in terms of controlled generation of ROS (DCFDA oxidation, H2O2 content) with greater elicitation of total antioxidant capacity (DPPH radical scavenging property), contends lipid peroxidation (accumulation of TBARS) as compared to the salt-sensitive cultivar IR 29. RP-HPLC based estimation of PISS-induced alteration in hormonal pools showed strong correlation between altered redox status (assessed in terms of redox biomarkers) and hormonal profile (endogenous titer of gibberellic acid (GA3), abscisic acid (ABA) and jasmonic acid (JA)) and germination and other physiological phenotypes (t50 value, allocation index, relative water content, and Na+ / K+ ratio) of the experimental rice germplasms, suggesting the influence of differential shift in redox status on germination hormones and early growth performances. Taken as a whole, the work proposes close connection between salinity induced changes in oxidative windows and hormonal profile of germinating seeds, necessary for better management of salinity stress in agriculture.

The Effect of Low Temperature on Physiological, Biochemical and Flowering Functions of Olive Tree in Relation to Genotype

Olive tree growth and reproduction are severely affected by temperature extremes, compromising fruit yield. In that aspect, the olive varieties “Koroneiki” and “Mastoidis” were employed in a mild cold stress experiment, imitating night frost incidents to assess their biochemical, physiological and reproductive functions in relation to genotype. The physiological performance of the stressed plants was not significantly altered, suggesting that both cultivars were well adapted to mild cold night stress. The biochemical response of the plants, regarding antioxidant enzymes, H2O2 and TBARS accumulation, confirmed that both cultivars could cope with the stress applied. The mRNA levels of the PPO gene, which participates in hydroxytyrosol biosynthesis and plant defense, were elevated after 24-h stress at 0 °C, in both cultivars with “Mastoidis” plants exhibiting higher levels for a longer period. Three more genes involved in hydroxytyrosol biosynthesis upregulated their expression levels as a response to cold stress. The numerous plant phenology aspects measured reinforced the conclusion that both cultivars responded to the stress applied. The results of the present study may contribute to better understanding olive tree adaptive responses to low temperature events, an abiotic stress condition that is often present in an open plantation, thus assisting farmers on breeding and cultivar selection.

In vivo effects of hemin and nitric oxide donors on parameters of heme metabolism in rat liver and serum

In vivo effects of hemin chloride (15 mg/kg body weight) and donors of nitrogen monoxide (NO) – sodium nitroprusside (SNP, 1 mg/kg) and substrate of NO-synthase L-arginine (L-Arg, 600 mg/kg) on the activity of key enzymes of heme synthesis (5-aminolevulinate synthase, ALAS) and heme degradation (heme oxygenase, HO), on the free heme level in liver and on the content of heme in blood serum of rats were studied. NO donors were administered alone or 30 min before hemin chloride injection. The level of free heme in liver was estimated by the ratio of holoenzyme and total tryptophan 2,3-dioxygenase (TDO) activities. Two hours after hemin chloride administration a significant increase in the level of heme-containing products and lipid peroxidation products (TBARS) was found in blood serum. These changes were accompanied by decrease in ALAS activity and by increase in holoenzyme activity and heme saturation of TDO, which was the result of free heme accumulation in liver. 24 hrs after administration of hemin chloride the content of heme in serum returned to normal level, while level of TBARS remained elevated. 24 hrs after hemin action a significant increase in the activities of HO and ALAS was observed in liver, while the degree of TDO heme saturation decreased, indicating the prevalence of heme degradation over its synthesis. Both NO donors did not affect the accumulation of heme in serum and liver first hours after hemin action. However, the specific features of SNP and L-Arg effects on the key enzyme of heme synthesis in liver and the TBARS level in serum were revealed. L-Arg, unlike SNP, prevented the accumulation of TBARS in serum, but did not prevent a decrease in ALAS activity 2 hrs after hemin chloride injection. The treatment by SNP itself caused an increase in TBARS level in serum, an increase in TDO activity and a decrease in ALAS activity in liver 2 hrs after action. Heme content in serum positively correlated with holoenzyme activity and heme saturation of TDO in liver. The pretreatment with NO donors did not affect the increase in HO activity, however, it blocked the induction of ALAS, a decrease in holoenzyme activity and heme saturation of TDO 24 hrs after the administration of hemin chloride. Thus, both SNP and Arg prevented a decrease in free heme level in liver, which might be due to heme nitrosylation in the presence of NO donors and, as a result, its slower degradation in the heme oxygenase reaction.

Characterization and storage stability of astaxanthin esters, fatty acid profile and α-tocopherol of lipid extract from shrimp (L. vannamei) waste with potential applications as food ingredient

In this work a lipid extract from shrimp waste was obtained and characterized. The most abundant fatty acids found were C16:0, C18:2n6c, C18:1n9c, C22:6n3, and C20:5n3. The extract contained all-trans-astaxanthin, two cis-astaxanthin isomers, 5 astaxanthin monoesters, and 10 astaxanthin diesters (7±1mg astaxanthin/g). C22:6n3 and C20:5n3 were the most frequent fatty acids in the esterified forms. Appreciable amounts of α-tocopherol and cholesterol were also found (126±11mg/g and 65±1mg/g, respectively). Little lipid oxidation was observed after 120days of storage at room temperature, revealed by a slight reduction of ω-3 fatty acids, but neither accumulation of TBARS nor formation of oxidized cholesterol forms was found. This is attributed to the antioxidant effect of astaxanthin and α-tocopherol, as their concentrations decreased as storage continued. The lipid extract obtained has interesting applications as food ingredient, owing to the coloring capacity and the presence of healthy components.

Trivalent chromium pretreatment alleviates the toxicity of oxidative damage in wheat plants exposed to hexavalent chromium

Treating plants with abiotic or biotic factors can lead to the establishment of a unique primed state of defense. Primed plants display enhanced defense reactions upon further challenge with environmental stressors. Here, we report that trivalent chromium (Cr(III)) pretreatment can alleviate hexavalent chromium (Cr(VI)) toxicity in 2-week-old wheat plants. The data indicate that Cr(III)-pretreated wheat displayed longer survival times and less heavy metal toxicity symptoms under Cr(VI) exposure than the control. To investigate the possible mechanism from an antioxidant defense perspective, we determined the H2O2 and lipid peroxide content (TBARS), the activities of antioxidant enzymes (SOD, CAT, APX and GR) and the antioxidant metabolite content (ascorbate and glutathione content, AsA/DHA and GSH/GSSG ratios) in pretreated wheat roots. The results showed that 0.5 μM Cr(III) pretreatment can alleviate oxidative damage, such as H2O2 and TBARS accumulation, in root tissues compared to the control during the first 3 days of Cr(VI) exposure. Furthermore, we determined that this pretreatment can significantly increase the antioxidant enzyme activities and total ascorbate and glutathione contents compared to the control treatment. In addition, redox homeostasis declined slightly in pretreated wheat compared to the control in the presence of Cr(VI). We discuss a possible mechanism for Cr(III)-mediated protection of wheat.

Oxidation and uptake of LDL by monocyte-derived macrophages from blood of patients with IHD

The main goal of this study was to test our hypothesis that monocyte-derived macrophages of patients with ischemic heart disease (IHD, MPIHD) are in vivo prestimulated (primed) or stimulated cells. Their capacity for LDL oxidation and uptake exceeds that of macrophages from healthy donors (MPN). Monocytes were isolated from blood of 18 healthy donors and 25 IHD patients and LDL preparations were obtained from plasma of 16 healthy donors (LDLN) and 15 patients with familial hypercholesterolemia (LDLH). Aerobic incubation of LDLN or LDLH with MPIHD resulted in earlier accumulation (by 1 h) of TBARS in LDL, earlier aggregation of LDL (1 h vs 3 h in the case of MPN), more pronounced LDL apoB fragmentation as well as increased LDL uptake with the increase in accumulation of total cholesterol (TCh; by 1.8–2.1-fold, p < 0.05–0.01) and the decrease in cell viability compared with MPN (p < 0.01). MPIHD and MPN exhibited more effective oxidation and uptake of LDLH than LDLN and in most tests this capacity (to oxidize and uptake LDL) increased under hypoxic conditions. These results demonstrate that macrophages of IHD patients are in vivo stimulated cells and that this stimulation, especially in combination with hypercholesterolemic LDL and local or generalized hypoxia, represent serious predisposition for onset or progression of atherosclerosis in IHD patients. The express test model based on MPIHD may be used for estimation of monocyte/macrophage stimulation in IHD patients as well as for optimization of drug therapy and screening new antiatherosclerotic and antiischemic drugs.

Antioxidant-mediated augmentation of ozone-induced membrane oxidation

The pulmonary epithelial lining fluid (ELF) contains substrates, e.g., ascorbic acid (AH2), uric acid (UA), glutathione (GSH), proteins, and unsaturated lipids, which undergo facile reaction with inhaled ozone (O3). Reactions near the ELF gas/liquid interface likely provide the driving force for O3 absorption (“reactive absorption”) and constrain O3 diffusion to the underlying epithelium. To investigate the potential mechanisms wherein O3/ELF interactions may induce cellular damage, we utilized a red cell membrane (RCM) model intermittently covered by an aqueous film to mimic the lung surface compartmentation, and evaluated exposure-mediated loss of acetylcholinesterase activity (AChE) and TBARS accumulation. In the absence of aqueous reactants, O3 exposure induced no detectable changes in AChE or TBARS. AH2 and GSH preferentially induced oxidative damage in a dose-dependent fashion. AH2-mediated RCM oxidation was not inhibited by superoxide dismutase, catalase, mannitol, or Fe chelators. O3 reaction with UA, Trolox, or albumin produced no RCM oxidation but oxidation occurred when AH2 was combined with UA or albumin. Rat bronchoalveolar lavage fluid (BALF) also induced RCM oxidation. However, in vivo O3 exposure dampened the extent of BALF-mediated RCM oxidation. Although we cannot completely rule out O3 diffusion to the RCM, product(s) derived from O3 + AH2/GSH reactions (possibly O3− or 1O2) likely initiated RCM oxidation and may suggest that in vivo, such secondary species account for O3 permeation through the ELF leading to cellular perturbations.

Oxymyoglobin oxidation and membranal lipid peroxidation initiated by iron redox cycle.

Oxymyoglobin is the main pigment in muscle tissues, responsible for the bright red color of fresh meat. Oxidation of the heme iron from the ferrous to the ferric metmyoglobin produces the brownish color that consumers find undesirable in fresh meat. The aim of this study was to elucidate the mechanism of oxymyoglobin oxidation in muscle tissues by using a model system containing oxymyoglobin and muscle membranes oxidized by an iron redox cycle. Oxidation of oxymyoglobin was determined from the decrease in absorption of the solution measured by a spectrophotometer at 582 nm. Lipid peroxidation was determined by accumulation of TBARS and conjugated dienes. The higher rates of oxidation of oxymyoglobin (20 microM) and lipid oxidation were achieved by using ferric iron and ascorbic acid at concentrations of 50 and 200 microM, respectively. Increasing the concentration of ascorbic acid to 2000 microM switched its effect to antioxidative. Increasing the concentration of oxymyoglobin from 20 to 80 microM inhibited lipid peroxidation by >90% and partially prevented oxymyoglobin oxidation.

UVA irradiation induces L-isoaspartyl formation in melanoma cell proteins

It has been reported that UVA effects are partly mediated by production of reactive oxygen species. Moreover, oxidative stress increases protein damage, involving the occurrence of isoaspartyl residues, a product of protein deamidation/isomerization reactions. This work was undertaken in order to study the effects of UVA irradiation, mediated by oxidation, on sensitive protein targets. Melanoma cells exposed to UVA rays have been chosen as a model for monitoring the occurrence of L-isoaspartyl sites. A dramatic increase of these abnormal residues, specifically recognized and methylated by the enzyme L-isoaspartate(D-aspartate) O-methyltransferase (PCMT; EC 2.1.1.77), can be detected after exposure of M14 cells to raising doses of UVA. The effect of UVA on NO and TBARS accumulation, as well as on DNA fragmentation, has also been investigated. NO formation parallels the increase in isoaspartyl formation, while lipid peroxidation occurs only at the highest UVA doses. No DNA fragmentation has been detected under the employed experimental conditions. These results, as a whole, indicate that protein damages are one of the early events on UVA-induced cell injury. The endogenous activity of PCMT remains remarkably stable under UVA treatment, suggesting that this enzyme might play a crucial role in the repair and/or disposal of damaged proteins in UVA-irradiated cells.

Tissue-Specific Fatty Acid and α-Tocopherol Profiles in Male Chickens Depending on Dietary Tuna Oil and Vitamin E Provision

The beneficial health-promoting effects of the long-chain polyunsaturated fatty acids (PUFA) of the n-3 series make them important constituents of human and animal diets. The effects of tuna oil or a combination of tuna oil with an increased level of vitamin E on the fatty acid profile and vitamin E distribution in tissues taken from cockerels were studied. Male chickens (Ross broiler breeders), penned on white wood shavings, were allocated into one of three groups with 12 birds per group and were fed from 10 wk of age on a commercial diet supplemented with 3% corn oil (control) or with 3% Tuna orbital oil (TO). Vitamin E was added at the rate of 40 mg/ kg, except in the third group in which the birds received a diet containing TO (3%) supplemented with 160 mg/kg vitamin E (TO+E). At 72 wk of age, the cockerels were killed, and tissues (liver, testes, heart, lung, kidney, spleen, thigh muscle, pancreas, internal fat, cerebellum, and cerebrum) were dissected for lipid and vitamin E analyses. Inclusion of TO in the cockerel diets significantly (P < 0.01) increased docosahexanoic acid (DHA) proportions in the major lipid fractions of the tissues with the brain being more resistant to lipid manipulation compared with the other tissues. Tissue enrichment with DHA took place at the expense of a decrease of n-6 PUFA. In the DHA-enriched tissues, vitamin E level decreased (P < 0.05), and susceptibility to peroxidation (TBARS accumulation) significantly (P < 0.01) increased. High vitamin E supplementation (160 mg/kg) in combination with TO prevented decrease of α-tocopherol concentration in the tissues and normalized or even increased their resistance to lipid peroxidation. There was tissue-specificity in response to dietary vitamin E supplementation; the liver was most responsive and the cerebellum was most resistant to vitamin E manipulation.

Hypochlorite-Induced Peroxidation of Egg Yolk Phosphatidylcholine is Mediated by Hydroperoxides

Using a chemiluminescent method, the consumption of HOCl/OCl was investigated during interaction with liposomes prepared from dimyristoylphos-phatidylcholine (DMPC) or egg yolk phosphatidylcholine (EYPC). The concentration of HOCl/OCl-decreased with time in the suspension of EYPC that contain unsaturated lipids and did not change in DMPC liposome suspensions. HOCl/OCl- was consumed more rapidly in peroxidized EYPC. The amount of double bonds was lowered by 40% in peroxidized liposomes and decreased by approximately one-third under the action of HOCl/OCl- in both native and peroxidized EYPC samples. Second-order rate constants for the interaction between HOCl and phospholipid double bonds of 0.50 M-1s-1 were calculated for native EYPC on basis of the consumption of HOCl/OCl- or from the decrease in concentration of double bonds. In peroxidized EYPC this reaction constant was similar as determined following changes in double bonds. It is concluded that the consumption of HOCl/OCl- increased in peroxidized liposomes due to additional reactions with lipid peroxidation products. tert-Butyl hydroperoxide and cumene hydroperoxide, or organic peroxides or epoxides (cis-9,10-epoxystearic acid; cholesterol-5α, bα-epoxide; trans-2,3-epoxy-butane; cis-2,3-epoxy-butane) were incorporated into liposomes and investigated in respect to their ability (1) to increase the consumption of HOCl/OCl- in DMPC liposomes, (2) to generate a non-enhanced chemiluminescence with HOCl/OCl- and (3) to evoke an accumulation of lipid peroxidation products (TBARS) in EYPC liposomes in the absence and presence of NaOCl. None of peroxides or epoxides tested showed any effect on the consumption of HOCI/OCl- or the generation of chemiluminescence. Nor increase of TBARS both in the absence or presence of HOCI/OCl-. In contrast, tert-butyl hydroperoxide and cumene hydroperoxide increased the consumption of HOCI/OCl- in DMPC liposomes and mediated a higher accumulation of TBARS in EYPC liposomes in the presence of HOCl/OCL- over the control. These data suggest that lipid peroxidation in EYPC can be initiated by the reaction of HOCI/OCL- with organic hydroperoxides.

Lipid Peroxidation Induced by H2O2-Activated Metmyoglobin and Detection of a Myoglobin-Derived Radical

The aim of this work was to better understand the oxidative processes which regulate lipid and myoglobin oxidation during an 8-day storage period of two bovine muscles: Longissimus lumborum (LL), stable from viewpoint of color stability, and Psoas major (PM), unstable. Lipid peroxidation (TBA-RS accumulation), induced by a H 2 O 2 -activated MetMb system, was greater in microsomal membranes from Psoas major muscle than from Longissimus lumborum muscle and particularly after 8 days of meat storage. These results could be partly explained by the differences in the phospholipids and fatty acids composition of microsomal fractions of two studied muscles. To better understand these oxidative processes in relation to muscle type and post-mortem storage time, it was measured in vitro, by optical and ESR spectroscopy, the formed radicals in a H 2 O 2 -activated MetMb system with or without microsomes. By optical spectroscopy, it was shown that the decay rate constant of the ferrylmyoglobin radical into ferric myoglobin was enhanced (6-fold) after addition of the microsomal membranes. No muscle effect was noted. With ESR spectroscopy, it was shown that a tyrosine peroxyl radical was formed. After addition of the microsomal membranes, the increase of the decay rate constant was very low (1.4-fold) but was greater when the microsomal fraction was extracted after 8 days of meat storage