Eggshell coloration is an indicator of dietary calcium in Common Pheasants (Phasianus colchicus)

According to the structural-function hypothesis, the eggshell pigment protoporphyrin, deposited at weak spots, can strengthen the shell structure when calcium is lacking in avian species. However, this hypothesis has not been tested in species that produce pigmented eggs of uniform ground colour without spotting patterns. We tested the structural-function hypothesis using 435 eggs produced on seven calcium diets (0.2–4.5%) given to Common Pheasants Phasianus colchicus, a species that produces a large number of eggs on a low-calcium diet with unspotted eggshells composed of a uniform ground colour of mainly protoporphyrin. We found that pheasants on the lowest calcium diet (0.2%), which had thinner eggshells, produced eggs containing more protoporphyrin-based coloration than four of six other diets, suggesting this species employs pigmentation as ground colour to strengthen eggshells when available calcium is low. Our results provide the first, at least partial support for a structural function for eggshell pigments producing ground colour without spotting in a species that is often calcium-limited. This pattern may be more widespread in other ground-nesting taxa that also produce large numbers of eggs with protoporphyrin-based ground colour and are potentially limited by calcium during breeding.     

Prenatal exposure to testosterone impairs oxidative damage repair efficiency in the domestic chicken (Gallus gallus)

Elevated levels of maternal androgens in avian eggs affect numerous traits, including oxidative stress. However, current studies disagree as to whether prenatal androgen exposure enhances or ameliorates oxidative stress. Here, we tested how prenatal testosterone exposure affects oxidative stress in female domestic chickens (Gallus gallus) during the known oxidative challenge of an acute stressor. Prior to incubation, eggs were either injected with an oil vehicle or 5 ng testosterone. At either 17 or 18 days post-hatch, several oxidative stress markers were assessed from blood taken before and after a 20 min acute stressor, as well as following a 25 min recovery from the stressor. We found that, regardless of yolk treatment, during both stress and recovery all individuals were in a state of oxidative stress, with elevated levels of oxidative damage markers accompanied by a reduced total antioxidant capacity. In addition, testosterone-exposed individuals exhibited poorer DNA damage repair efficiencies in comparison with control individuals. Our work suggests that while yolk androgens do not alter oxidative stress directly, they may impair mechanisms of oxidative damage repair.     

线粒体锚定对凋亡诱导因子抗氧化应激功能的影响

目的:构建带线粒体锚定信号肽的凋亡诱导因子(AIF)融合表达载体,研究在A549细胞中AIF线粒体锚定与其抗氧化应激功能的关系。方法:利用PCR将AIF原有线粒体定位信号(1-120 aa)替换成具有锚定功能的细胞色素c氧化酶Ⅳ亚型(COXⅣ)线粒体定位信号,并将COX-AIF克隆至pEGFP-N1和pDsRed1-N1载体,构建COX-AIF-GFP和COX-AIF-RFP融合表达载体;利用免疫印迹和激光共聚焦技术检测COX-AIF-GFP和COX-AIF-RFP的表达及其与线粒体的共定位;利用DCF染色和流式细胞技术检测A549细胞内过氧化物的水平。结果:表达了COX-AIF-GFP和COX-AIF-RFP融合蛋白,COX-AIF-GFP/RFP及AIF-RFP/RFP均定位于线粒体;与野生型AIF-RFP相比,COX-AIF-RFP可显著提高A549细胞的抗氧化应激能力。结论:AIF抗氧化应激能力依赖其在线粒体内膜的锚定。     

Maternal exposure to multi-wall carbon nanotubes does not induce embryo-fetal developmental toxicity in rats

BACKGROUND: Although the potential risk of carbon nanotubes (CNTs) to humans has recently increased due to expanding production and widespread use, the potential adverse effects of CNTs on embryo–fetal development have not yet been determined. METHODS: This study investigated the potential effects of multi‐wall CNTs (MWCNTs) on pregnant dams and embryo–fetal development in rats. MWCNTs were administered to pregnant rats by gavage at 0, 40, 200, and 1,000 mg/kg/day. All dams were subjected to Cesarean section on day 20 of gestation, and the fetuses were examined for any morphological abnormalities. RESULTS: All animals survived to the end of the study. A decrease in thymus weight was observed in the high dose group in a dose‐dependent manner. However, maternal body weight, food consumption, and oxidant–antioxidant balance in the liver were not affected by treatment with MWCNTs. No treatment‐related differences in gestation index, fetal deaths, fetal and placental weights, or sex ratio were observed between the groups. Morphological examinations of the fetuses demonstrated no significant difference in incidences of abnormalities between the groups. CONCLUSIONS: The results show that repeated oral doses of MWCNTs during pregnancy induces minimal maternal toxicity and no embryo–fetal toxicity at 1,000 mg/kg/day in rats. The no‐observed‐adverse‐effect level of MWCNTs is considered to be 200 mg/kg/day for dams and 1,000 mg/kg/day for embryo–fetal development. In this study, the dosing formulation was not analyzed to determine the degree of reaggregation (or not), nor were blood levels of CNT's measured in the dosed animals to verify or characterize absorption. Birth Defects Res (Part B) 92:69–76, 2011. © 2011 Wiley‐Liss, Inc.     

Yolk testosterone reduces oxidative damages during postnatal development

Conditions experienced during early life can influence the development of an organism and several physiological traits, even in adulthood. An important factor is the level of oxidative stress experienced during early life. In birds, extra-genomic egg substances, such as the testosterone hormone, may exert a widespread influence over the offspring phenotype. Interestingly, testosterone can also upregulate the bioavailability of certain antioxidants but simultaneously increases the susceptibility to oxidative stress in adulthood. However, little is known about the effects of maternally derived yolk testosterone on oxidative stress in developing birds. Here, we investigated the role of yolk testosterone on oxidative stress of yellow-legged gull chicks during their early development by experimentally increasing yolk testosterone levels. Levels of antioxidants, reactive oxygen species and lipid oxidative damage were determined in plasma during nestlings'' growth. Our results revealed that, contrary to control chicks, birds hatched from testosterone-treated eggs did not show an increase in the levels of oxidative damage during postnatal development. Moreover, the same birds showed a transient increase in plasma antioxidant levels. Our results suggest that yolk testosterone may shape the oxidative stress-resistance phenotype of the chicks during early development owing to an increase in antioxidant defences and repair processes.     

Antioxidant composition of selected high alpine plant species from different altitudes

Selected high alpine plant species were collected from different elevations in the Obergurgl/Ötztal subnival and nival regions in Austria to investigate the content of antioxidants in plants growing under the particular in vivo conditions experienced in this area (e.g. chilling stress, short vegetation period and high irradiation). The contents of antioxidants (ascorbic acid, tocopherol and glutathionc) and photosynthetic pigments were measured throughout the day. The contents of most compounds were found to follow a diurnal rhythm, with the maximum occurring at midday and the minimum during the night. It was not clear whether these fluctuations were temperature-dependent or light-dependent. Analyses of the antioxidant spectrum in the same plant species at different altitudes (and thus under different environmental conditions: as altitude increases, for example, day temperature decreases and light intensity increases) revealed that the total amount of antioxidants increases as altitude increases. This enhancement was mainly due to ascorbic acid contents. Each plant species displayed a specific reaction to the increase in stress that accompanies an increase in altitude, resulting in a broad adaptation spectrum for these plants. The present study suggests that the combined effect of lower temperature and higher light intensity induces higher antioxidant contents.     

Maternal predator-exposure has lifelong consequences for offspring learning in threespined sticklebacks

Learning is an important form of phenotypic plasticity that allows organisms to adjust their behaviour to the environment. An individual''s learning performance can be affected by its mother''s environment. For example, mothers exposed to stressors, such as restraint and forced swimming, often produce offspring with impaired learning performance. However, it is unclear whether there are maternal effects on offspring learning when mothers are exposed to ecologically relevant stressors, such as predation risk. Here, we examined whether maternal predator-exposure affects adult offsprings’ learning of a discrimination task in threespined sticklebacks (Gasterosteus aculeatus). Mothers were either repeatedly chased by a model predator (predator-exposed) or not (unexposed) while producing eggs. Performance of adult offspring from predator-exposed and unexposed mothers was assessed in a discrimination task that paired a particular coloured chamber with a food reward. Following training, all offspring learned the colour-association, but offspring of predator-exposed mothers located the food reward more slowly than offspring of unexposed mothers. This pattern was not driven by initial differences in exploratory behaviour. These results demonstrate that an ecologically relevant stressor (predation risk) can induce maternal effects on offspring learning, and perhaps behavioural plasticity more generally, that last into adulthood.     

Cyclic oxidation and reduction of protein methionine residues is an important antioxidant mechanism

Almost all forms of reactive oxygen species (ROS) oxidize methionine residues of proteins to a mixture of the R- and S-isomers of methionine sulfoxide. Because organisms contain methionine sulfoxide reductases (Msr's) that can catalyze the thioredoxin-dependent reduction of the sulfoxides back to methionine, it was proposed that the cyclic oxidation/reduction of methionine residues might serve as antioxidants to scavenge ROS, and also to facilitate the regulation of critical enzyme activities. We summarize here results of studies showing that organisms possess two different forms of Msr – namely, MsrA that catalyzes reduction of the S-isomer and MsrB that catalyzes the reduction of the R-isomer. Deletion of the msrA gene in mice leads to increased sensitivity to oxidative stress and to a decrease (40%) in the maximum lifespan. This suggests that elimination of both Msr's would have more serious consequences.     

Salt-Induced Changes in Physio-Biochemical and Antioxidant Defense System in Mustard Genotypes

Salinity stress is a major factor limiting plant growth and productivity of many crops including oilseed. The present study investigated the identification of salt tolerant mustard genotypes and better understanding the mechanism of salinity tolerance. Salt stresses significantly reduced relative water content (RWC), chlorophyll (Chl) content, K⁺ and K⁺ /Na⁺ ratio, photosynthetic rate (P_N), transpiration rate (Tr), stomatal conductance (gs), intercellular CO₂ concentration (Ci) and increased the levels of proline (Pro) and lipid peroxidation (MDA) contents, Na⁺ , superoxide (O₂^•− ) and hydrogen peroxide (H₂O₂) in both tolerant and sensitive mustard genotypes. The tolerant genotypes maintained higher Pro and lower MDA content than the salt sensitive genotypes under stress condition. The activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), glutathione peroxidase (GPX), monodehydroascorbate reductase (MDHAR) and dehydroascorbate reductase (DHAR) were increased with increasing salinity in salt tolerant genotypes, BJ-1603, BARI Sarisha-11 and BARI Sarisha-16, but the activities were unchanged in salt sensitive genotype, BARI Sarisha-14. Besides, the increment of ascorbate peroxidase (APX) activity was higher in salt sensitive genotype as compared to tolerant ones. However, the activities of glutathione reductase (GR) and glutathione S-transferase (GST) were increased sharply at stress conditions in tolerant genotypes as compared to sensitive genotype. Higher accumulation of Pro along with improved physiological and biochemical parameters as well as reduced oxidative damage by up-regulation of antioxidant defense system are the mechanisms of salt tolerance in selected mustard genotypes, BJ-1603 and BARI Sarisha-16.     

Embryonic exposure to corticosterone modifies the juvenile stress response, oxidative stress and telomere length

Early embryonic exposure to maternal glucocorticoids can broadly impact physiology and behaviour across phylogenetically diverse taxa. The transfer of maternal glucocorticoids to offspring may be an inevitable cost associated with poor environmental conditions, or serve as a maternal effect that alters offspring phenotype in preparation for a stressful environment. Regardless, maternal glucocorticoids are likely to have both costs and benefits that are paid and collected over different developmental time periods. We manipulated yolk corticosterone (cort) in domestic chickens (Gallus domesticus) to examine the potential impacts of embryonic exposure to maternal stress on the juvenile stress response and cellular ageing. Here, we report that juveniles exposed to experimentally increased cort in ovo had a protracted decline in cort during the recovery phase of the stress response. All birds, regardless of treatment group, shifted to oxidative stress during an acute stress response. In addition, embryonic exposure to cort resulted in higher levels of reactive oxygen metabolites and an over-representation of short telomeres compared with the control birds. In many species, individuals with higher levels of oxidative stress and shorter telomeres have the poorest survival prospects. Given this, long-term costs of glucocorticoid-induced phenotypes may include accelerated ageing and increased mortality.     

Induction of Haem Oxygenase as a Defence Against Oxidative Stress

Cells respond to metabolic perturbations by producing specific stress proteins. Exposure of mammalian cells to various forms of oxidative stress induces haem oxygenase, the rate-limiting enzyme in haem degradation. This response is proposed to represent an antioxidant defence operating at two different stages simultaneously. It (i) decreases the levels of the potential pro-oxidants haem and haem proteins such as cytochrome P-450 and protoporphyrinogen oxidase, and (ii) increases the tissue concentrations of antio-xidatively active bile pigments.     

No evidence for an indirect benefit from female mate preference in Arctic charr Salvelinus alpinus,but female ornamentation decreases offspring viability

Female mate choice is considered an important evolutionary agent, but there has been an ongoing debate over the fitness consequences it produces, especially in species that have a resource‐free mating system. We examined a potential fitness benefit resulting from the pre‐spawning mate preference in Arctic charr Salvelinus alpinus, a salmonid fish with no parental care. The females were first allowed to discriminate behaviourally between two males presented to them in a free choice test. We then tested with controlled fertilizations whether the females would accrue indirect genetic benefits for their offspring, as measured by embryonic viability, if they had mated with the male they preferred. Both parental identities influenced offspring survivorship, but the females did not consistently prefer the male which gave her the higher reproductive success. Neither was the degree of male red breeding coloration associated with female preference or the observable genetic quality. In contrast, there was a negative relationship between female coloration and her offspring survivorship, suggesting a significant trade‐off in resource investment between sexual ornamentation and reproduction. To conclude, the potential indirect fitness consequences arising from females' pre‐spawning mate preference seem to be negligible in early stages of development of Arctic charr. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 103 , 602–611.     

Peroxiredoxin 2, glutathione peroxidase,and catalase in the cytosol and membrane of erythrocytes under H2O2-induced oxidative stress

Abstract

Erythrocytes are continuously exposed to risk of oxidative injury due to oxidant oxygen species. To prevent damage, they have antioxidant agents namely, catalase (Cat), glutathione peroxidase (GPx), and peroxiredoxin 2 (Prx2). Our aim was to contribute to a better understanding of the interplay between Prx2, Cat, and GPx under H₂O₂-induced oxidative stress, by studying their changes in the red blood cell cytosol and membrane, in different conditions. These three enzymes were quantified by immunoblotting. Malondialdehyde, that is, lipoperoxidation (LPO) in the erythrocyte membrane, and membrane-bound hemoglobin (MBH) were evaluated, as markers of oxidative stress. We also studied the erythrocyte membrane protein profile, to estimate how oxidative stress affects the membrane protein structure. We showed that under increasing H₂O₂ concentrations, inhibition of the three enzymes with or without metHb formation lead to the binding of Prx2 and GPx (but not Cat) to the erythrocyte membrane. Prx2 was detected mainly in its oxidized form and the linkage of metHb to the membrane seems to compete with the binding of Prx2. Catalase played a major role in protecting erythrocytes from high exogenous flux of H₂O₂, since whenever Cat was active there were no significant changes in any of the studied parameters. When only Cat was inhibited, Prx2 and GPx were unable to prevent H₂O₂-induced oxidative stress resulting in increasing MBH and membrane LPO. Additionally, the inhibition of one or more of these enzymes induced changes in the anchor/linker proteins of the junctional complexes of the membrane cytoskeleton–lipid bilayer, which might lead to membrane destabilization.     

Cerium oxide nanoparticles prevent apoptosis in primary cortical culture by stabilizing mitochondrial membrane potential

Abstract

Cerium oxide nanoparticles (CNPs) of spherical shape have unique antioxidant capacity primarily due to alternating + 3 and + 4 oxidation states and crystal defects. Several studies revealed the protective efficacies of CNPs in cells and tissues against the oxidative damage. However, its effect on mitochondrial functioning, downstream effectors of radical burst and apoptosis remains unknown. In this study, we investigated whether CNPs treatment could protect the primary cortical cells from loss of mitochondrial membrane potential (Δψ_m) and Δψ_m-dependent cell death. CNPs with spherical morphology and size range 7–10 nm were synthesized and utilized at a concentration of 25 nM on primary neuronal culture challenged with 50 μM of hydrogen peroxide (H₂O₂). We showed that optimal dose of CNPs minimized ROS content of the cells and also curbed related surge in cellular calcium flux. Importantly, CNPs treatment prevented apoptotic loss of cell viability. Reduction in the apoptosis could be successfully attributed to the maintenance of Δψ_m and restoration of major redox equivalents NADH/NAD⁺ ratio and cellular ATP. These findings, therefore, suggest possible route of CNPs protective efficacies in primary cortical culture.     

植物对锰的吸收运输及对过量锰的抗氧化响应

锰（Mn）毒是酸性土壤上限制作物生长的重要因素。植物体内Mn^2＋吸收运输的转运蛋白或将Mn^2＋分隔储存于内膜细胞器（如液泡）中,或在细胞内Mn^2＋运输及调节中起重要作用。近年,编码这些转运蛋白的基因已被分离鉴定。另外,高Mn胁迫极易诱导植物产生氧化胁迫,抗氧化系统在清除高蝴迫诱导产生的活性氧过程中起到重要作用。文章重点就承担Mn^2＋跨膜运输的膜转运蛋白以及植物抗氧化系统对高蝴迫的响应两方面进行了综述,并结合作者的研究提出看法和展望。     

Testing the carotenoid-based sexual signalling mechanism by altering CYP2J19 gene expression and colour in a bird species

Ornaments can evolve to reveal individual quality when their production/maintenance costs make them reliable as ‘signals’ or if their expression level is intrinsically linked to condition by some unfalsifiable mechanism (indices). The latter has been mostly associated with traits constrained by body size. In red ketocarotenoid-based colorations, that link could, instead, be established with cell respiration at the inner mitochondrial membrane (IMM). The production mechanism could be independent of resource (yellow carotenoids) availability, thus discarding costs linked to allocation trade-offs. A gene coding for a ketolase enzyme (CYP2J19) responsible for converting dietary yellow carotenoids to red ketocarotenoids has recently been described. We treated male zebra finches with an antioxidant designed to penetrate the IMM (mitoTEMPO) and a thyroid hormone (triiodothyronine) with known hypermetabolic effects. Among hormone controls, MitoTEMPO downregulated CYP2J19 in the bill (a red ketocarotenoid-based ornament), supporting the mitochondrial involvement in ketolase function. Both treatments interacted when increasing hormone dosage, indicating that mitochondria and thyroid metabolisms could simultaneously regulate coloration. Moreover, CYP2J19 expression was positively correlated to redness but also to yellow carotenoid levels in the blood. However, treatment effects were not annulated when controlling for blood carotenoid variability, which suggests that costs linked to resource availability could be minor.     

Antioxidant capacity of <Emphasis Type="Italic">Brassica juncea</Emphasis> plants exposed to elevated levels of copper

Brassica juncea L. eight-day-old seedlings treated with various concentrations (50–200 µM) of copper for 48 h accumulated Cu more in the roots than in leaves. Accumulation of copper resulted in more active lipid peroxidation and depletion of glutathione (GSH) pools in both roots and shoots, which was attributed to copper-induced additional oxidative stress. Activities of ascorbate peroxidase and superoxide dismutase were higher in both roots and shoots while catalase activity increased in leaves but remained unchanged in roots in response to copper accumulation. Changes in lipid peroxidation, GSH content, and antioxidant enzyme activities suggest that oxidative damage may be involved in copper toxicity.From Fiziologiya Rastenii, Vol. 52, No. 2, 2005, pp. 233–237.Original English Text Copyright © 2005 by Devi, Prasad.This article was submitted by the authors in English.This revised version was published online in April 2005 with a corrected cover date.     

Effect of iron supplementation on oxidative stress and antioxidant status in iron-deficiency anemia

This study was designed to measure the effect of iron supplementation on antioxidant status in iron-deficient anemia, including the time for hemoglobin normalization and at the time of filling of iron body stores. The extent of plasma lipid peroxidation was evaluated by measuring the levels of malondialdehyde and glutathione peroxidase (GSH-Px), and the activities of superoxide dismutase (SOD) and catalase in 63 patients with iron-deficiency anemia before and after 6 wk of iron supplementation and at the time when body iron stores are saturated. After 6 wk of iron supplementation, a significant decrease of oxidative stress was observed in the treated subjects relative to controls (p<0.05). No significant differences existed between treated patients at 6 wk and at the end of the study. The erythrocyte levels of catalase, SOD, and GSH-Px were significantly lower in treated patients relative to controls (p<0.05). These levels increased after 6 wk of supplementation (p<0.05) and showed no significant differences with those at the end of the study.