Role of Yrn2 under oxidative stress in Deinococcus radiodurans.

Among the two Y RNAs in Deinococcus radiodurans, the functional properties of Yrn2 are still not known. Yrn2 although consists of a long stem-loop for Rsr binding, differs from Yrn1 in the effector binding site. An initial study on Yrn2 delineated it to be a UV-induced noncoding RNA. Apart from that Yrn2 has scarcely been investigated. In the current study, we identified Yrn2 as an γ-radiation induced Y RNA, which is also induced upon H2O2 and mitomycin treatment. Ectopically expressed Yrn2 appeared to be nontoxic to the cell growth. An overabundance of Yrn2 was found to ameliorate cell survival under oxidative stress through the detoxification of intracellular reactive oxygen species with a subsequent decrease in total protein carbonylation. A significant accumulation of intracellular Mn(II) with unaltered Fe(II) and Zn(II) with detected while Yrn2 is overabundant in the cells. This study identified the role of a novel Yrn2 under oxidative stress in D. radiodurans.

A novel ionizing radiation-induced small RNA, DrsS, promotes the detoxification of reactive oxygen species in Deinococcus radiodurans.

A plethora of gene regulatory mechanisms with eccentric attributes in Deinoccocus radiodurans confer it to possess a distinctive ability to survive under ionizing radiation. Among the many regulatory processes, small RNA (sRNA)-mediated regulation of gene expression is prevalent in bacteria but barely investigated in D. radiodurans. In the current study, we identified a novel sRNA, DrsS, through RNA-seq analysis in D. radiodurans cells while exposed to ionizing radiation. Initial sequence analysis for promoter identification revealed that drsS is potentially co-transcribed with sodA and dr_1280 from a single operon. Elimination of the drsS allele in D. radiodurans chromosome resulted in an impaired growth phenotype under γ-radiation. DrsS has also been found to be upregulated under oxidative and genotoxic stresses. Deletion of the drsS gene resulted in the depletion of intracellular concentration of both Mn2+ and Fe2+ by ~70% and 40%, respectively, with a concomitant increase in carbonylation of intracellular protein. Complementation of drsS gene in ΔdrsS cells helped revert its intracellular Mn2+ and Fe2+ concentration and alleviated carbonylation of intracellular proteins. Cells with deleted drsS gene exhibited higher sensitivity to oxidative stress than wild-type cells. Extrachromosomally expressed drsS in ΔdrsS cells retrieved its oxidative stress resistance properties by catalase-mediated detoxification of reactive oxygen species (ROS). In vitro binding assays indicated that DsrS directly interacts with the coding region of the katA transcript, thus possibly protecting it from cellular endonucleases in vivo. This study identified a novel small RNA DrsS and investigated its function under oxidative stress in D. radiodurans. IMPORTANCE: Deinococcus radiodurans possesses an idiosyncratic quality to survive under extreme ionizing radiation and, thus, has evolved with diverse mechanisms which promote the mending of intracellular damages caused by ionizing radiation. As sRNAs play a pivotal role in modulating gene expression to adapt to altered conditions and have been delineated to participate in almost all physiological processes, understanding the regulatory mechanism of sRNAs will unearth many pathways that lead to radioresistance in D. radiodurans. In that direction, DrsS has been identified to be a γ-radiation-induced sRNA, which is also induced by oxidative and genotoxic stresses. DrsS appeared to activate catalase under oxidative stress and detoxify intracellular ROS. This sRNA has also been shown to balance intracellular Mn(II) and Fe concentrations protecting intracellular proteins from carbonylation. This novel mechanism of DrsS identified in D. radiodurans adds substantially to our knowledge of how this bacterium exploits sRNA for its survival under stresses.

Reduced protein carbonylation on hormone therapy is associated with improved fibrinolysis in postmenopausal women: the impact of PAI-1 and TAFI activity.

Hormone therapy (HT) has been reported to reduce protein carbonylation (PC) in postmenopausal women, in whom fibrinolysis is impaired. We investigated whether PC affects fibrinolysis and if HT modulates this effect. We enrolled 150 women aged 55.5 ± 4.7 years in a randomized interventional open-label study, including 50 on standard oral HT, 50 on ultra-low-dose HT, and 50 controls. PC, along with global fibrinolysis (clot lysis time, CLT), fibrinolysis proteins, and prothrombotic markers were determined at baseline and at 24 weeks. Patients with the baseline top quartile PC (> 2.07 nM/mg protein) had 10.3% longer CLT, higher activity (but not antigen) of TAFI (+ 19.9%) and PAI-1 (+ 68.1%) compared to the remainder. No differences were observed in thrombin generation, factor VIII, plasminogen or α2-antiplasmin. On-treatment PC decreased by 16.4% (p < 0.0001), without differences related to the type of HT, compared to baseline and by 30% compared to controls, in whom PC and fibrinolysis markers remained unchanged. Patients with PC > 2.07 nM/mg had shortened CLT during HT compared to baseline, along with lower PAI-1 (-69%) and TAFI (-26%) activity. In this subgroup CLT was 5.8% shorter compared to controls with the highest PC. In postmenopausal women with increased PC, HT was accompanied by PC reduction and faster clot lysis together with decreased PAI-1 and TAFI activity.

Elevated plasma protein carbonylation increases the risk of ischemic cerebrovascular events in patients with atrial fibrillation: association with a prothrombotic state.

INTRODUCTION: Plasma protein carbonylation that reflects oxidative stress has been demonstrated to be associated with the prothrombotic fibrin clot phenotype. However, the role of protein carbonyls (PC) in predicting ischemic stroke in atrial fibrillation (AF) is largely unknown. This study aimed to investigate whether PC increase the risk of stroke in anticoagulated AF patients during follow-up. METHODS: In 243 AF patients on anticoagulation (median age 69 years; median CHA2DS2-VASc of 4), we measured plasma PC using the assay by Becatti, along with plasma clot permeability (Ks), clot lysis time (CLT), thrombin generation, and fibrinolytic proteins, including plasminogen activator inhibitor type 1 (PAI-1) and thrombin activatable fibrinolysis inhibitor (TAFI). Ischemic stroke, major bleeding, and mortality were recorded during a median follow-up of 53 months. RESULTS: Plasma PC levels (median, 3.16 [2.54-3.99] nM/mg protein) at baseline showed positive associations with age (P < 0.001), CHA2DS2-VASc (P = 0.003), and N-terminal B-type natriuretic peptide (P = 0.001), but not with type of AF or comorbidities except for heart failure (P = 0.007). PC levels were correlated with CLT (r = 0.342, P < 0.001), endogenous thrombin potential (r = 0.217, P = 0.001) and weakly with Ks (r = -0.145, P = 0.024), but not with fibrinogen, PAI-1, or TAFI levels. Stroke was recorded in 20 patients (1.9%/year), who had at baseline 36% higher PC levels (P < 0.001). Elevated PC (P = 0.003) at baseline were independently associated with stroke risk. CONCLUSION: Our findings suggest that in patients with AF enhanced protein carbonylation is associated with increased "residual" risk of stroke despite anticoagulation, which is at least in part due to unfavorably altered fibrin clot phenotype.

A novel two-way rebalancing strategy for identifying carbonylation sites.

BACKGROUND: As an irreversible post-translational modification, protein carbonylation is closely related to many diseases and aging. Protein carbonylation prediction for related patients is significant, which can help clinicians make appropriate therapeutic schemes. Because carbonylation sites can be used to indicate change or loss of protein function, integrating these protein carbonylation site data has been a promising method in prediction. Based on these protein carbonylation site data, some protein carbonylation prediction methods have been proposed. However, most data is highly class imbalanced, and the number of un-carbonylation sites greatly exceeds that of carbonylation sites. Unfortunately, existing methods have not addressed this issue adequately. RESULTS: In this work, we propose a novel two-way rebalancing strategy based on the attention technique and generative adversarial network (Carsite_AGan) for identifying protein carbonylation sites. Specifically, Carsite_AGan proposes a novel undersampling method based on attention technology that allows sites with high importance value to be selected from un-carbonylation sites. The attention technique can obtain the value of each sample's importance. In the meanwhile, Carsite_AGan designs a generative adversarial network-based oversampling method to generate high-feasibility carbonylation sites. The generative adversarial network can generate high-feasibility samples through its generator and discriminator. Finally, we use a classifier like a nonlinear support vector machine to identify protein carbonylation sites. CONCLUSIONS: Experimental results demonstrate that our approach significantly outperforms other resampling methods. Using our approach to resampling carbonylation data can significantly improve the effect of identifying protein carbonylation sites.

Protein Carbonylation Contributes to Prothrombotic Fibrin Clot Phenotype in Acute Ischemic Stroke: Clinical Associations.

BACKGROUND: Acute ischemic stroke (AIS) is associated with enhanced oxidative stress and unfavorably altered fibrin clot properties. We investigated determinants of plasma protein carbonylation (PC) in AIS, its impact on the prothrombotic state, and prognostic value during follow-up. METHODS: We included 98 consecutive AIS patients aged 74±12 years (male:female ratio, 50:48 [51%:49%]) at the Neurology Center in Warsaw, Poland, between January and December 2014. As many as 74 (75.5%) patients underwent thrombolysis, and 24 were unsuitable for thrombolysis. We determined plasma PC, along with thrombin generation, fibrin clot permeability, and clot lysis time on admission, at 24 hours, and 3 months. Stroke severity was assessed using the National Institutes of Health Stroke Scale and stroke outcome with the modified Rankin Scale. Hemorrhagic transformation was assessed on the computed tomography scan within 48 hours from the symptom onset, while stroke-related mortality was evaluated at 3 months. RESULTS: On admission, PC levels (median, 4.61 [3.81-5.70] nM/mg protein) were associated with the time since symptom onset (r=0.41; P<0.0001) and with the National Institutes of Health Stroke Scale score (P=0.36; P=0.0003). Higher PC levels on admission correlated with denser fibrin clot formation and prolonged clot lysis time but not with thrombin generation. In thrombolysed patients, lower PC levels were observed after 24 hours (-34%) and at 3 months (-23%; both P<0.001). PC levels at baseline and after 24 hours predicted the modified Rankin Scale score >2 at 3 months (OR, 1.90 [95% CI, 1.21-3.00]; OR, 2.19 [95% CI, 1.39-3.44], respectively). Higher PC at baseline predicted hemorrhagic transformation of stroke (OR, 1.95 [95% CI, 1.02-3.74]) and stroke-related mortality (OR, 2.02 [95% CI, 1.08-3.79]), while higher PC at 24 hours predicted solely stroke-related mortality (OR, 2.11 [95% CI, 1.28-3.46]). CONCLUSIONS: Elevated plasma PC levels in patients with AIS, related to prothrombotic fibrin clot properties, are associated with stroke severity. Thrombolysis reduces the extent of PC. The current study suggests a prognostic value of PC in AIS.

Ammonium sulfate-based prefractionation improved proteome coverage and detection of carbonylated proteins in Arabidopsis thaliana leaf extract.

MAIN CONCLUSION: Ammonium sulfate is well known to salt out proteins at high concentrations. The study revealed that it can serve to increase by 60% the total number of identified carbonylated proteins by LC-MS/MS. Protein carbonylation is a significant post-translational modification associated with reactive oxygen species signaling in animal and plant cells. However, the detection of carbonylated proteins involved in signaling is still challenging, as they only represent a small subset of the proteome in the absence of stress. In this study, we investigated the hypothesis that a prefractionation step with ammonium sulphate will improve the detection of the carbonylated proteins in a plant extract. For this, we extracted total protein from the Arabidopsis thaliana leaves and subjected the extract to stepwise precipitation with ammonium sulfate to 40%, 60%, and 80% saturation. The protein fractions were then analyzed by liquid chromatography-tandem mass spectrometry for protein identification. We found that all the proteins identified in the non-fractionated samples were also found in the prefractionated samples, indicating no loss was incurred during the prefractionation. About 45% more proteins were identified in the fractionated samples compared to the non-fractionated total crude extract. When the prefractionation steps were combined with the enrichment of carbonylated proteins labeled with a fluorescent hydrazide probe, several carbonylated proteins, which were unseen in the non-fractionated samples, became visible in the prefractionated samples. Consistently, the prefractionation method allowed to identify 63% more carbonylated proteins by mass spectrometry compared to the number of carbonylated proteins identified from the total crude extract without prefractionation. These results indicated that the ammonium sulfate-based proteome prefractionation can be used to improve proteome coverage and identification of carbonylated proteins from a complex proteome sample.

Analysis of optical absorption of photoaged human skin using a high-frequency illumination microscopy analysis system.

Skin is composed of different layers, including the stratum corneum, epidermal living layer and papillary and reticular dermis. Each has specific optical properties due to differences in their biological components. Alterations in the skin's cutaneous biological components resulting from photoaging caused by chronic exposure to UV light affect the deterioration of appearance associated with the skin's optical properties. Various methods for analysing cutaneous optical properties have been previously proposed, including mathematical models and computer simulations. However, these were insufficient to elucidate changes in each skin layer and comprehensively understand the skin's integrated optical properties. We focused on UV-induced yellowing of the facial skin. We evaluated site-specific optical absorption of human skin tissue sections to investigate the yellowish discoloration, which is suggested to be related to the photodamage process. The method includes our original technique of separating the transmitted and scattered light using high-frequency illumination microscopy, leading to microscopic analysis of the tissue's optical absorption in the regions of interest. In analysing the sun-exposed facial skin tissue sections, we successfully showed that dermal regions of aged skin have increased absorption at 450 nm, where yellowish colours are complemented. Furthermore, we confirmed that elastic fibres with observable histological disorder resulting from photodamage are a prominent source of high optical absorption. We detected changes in the skin's optical absorption associated with dermal degeneration resulting from photodamage using a novel optical microscopy technique. The results provide a base for the evaluation of optical property changes for both yellowing discoloration and other tissue disorders.

Oxidative stress effects are not correlated with differences in heat tolerance among congeners of Mytilus.

The physiological mechanisms that limit thermal tolerance are broadly relevant to comparative biology and global change. Species differences in macromolecular stability play important roles in evolved patterns of heat tolerance, but other mechanisms such as oxidative stress have also been hypothesized to contribute. For example, mussels in the genus Mytilus exhibit evolved physiological differences at several levels of organization that have been linked with interspecific differences in whole-organism heat tolerance. Both omics and behavioral studies suggested that variation in resistance to oxidative stress plays a role in these differences. Functional data are needed to test this hypothesis. Here, we compared three Mytilus congeners to examine whether susceptibility to oxidative stress contributes to acute heat tolerance. We assayed the activity of two antioxidant enzymes (catalase, superoxide dismutase), as well as levels of oxidative damage to lipids, DNA and individual proteins (using gel-based proteomics methods). In addition, we assessed these oxidative stress responses after repeated episodes of heat stress experienced in air or while immersed in seawater, given that survival and competitive outcomes between Mytilus congeners differ in these two contexts. The results are generally inconsistent with patterns that would be expected if oxidative stress contributes to thermal sensitivity. Rather, the more heat-tolerant congeners suffer comparable or even elevated levels of oxidative damage. As predicted, different treatment contexts led to distinct changes in proteome-wide abundance patterns and, to a lesser extent, protein carbonylation profiles. Overall, the results question the relevance of oxidative damage as a mediator of heat tolerance in this genus.

Specific detection of protein carbonylation sites by 473 nm photodissociation mass spectrometry.

The study of protein oxidation remains a challenge despite the biomedical interest in reliable biomarkers of oxidative stress. This is particularly true for carbonylations although, recently, liquid chromatography-mass spectrometry techniques (LC-MS) have been proposed to detect this non-enzymatic and poorly distributed oxidative modification of proteins using untargeted or carbonyl-reactive probe methods. These methods proved to be feasible but could not preserve the dynamic range of the protein sample, making it impossible to quantify oxidatively modified proteoforms compared with native proteoforms. Here, we propose an innovative method based on the implementation of a reactive carbonyl probe conjugated with a laser-sensitive chromophore, dabcyl-aminooxy, which confers optical specificity to the LC-MS approach. In addition, our protein carbonyl detection method allows us to localize individual carbonylation sites by observing fragments of derivatized oxidized peptides. Two model proteins, alpha-synuclein and beta-lactoglobulin, were oxidized and carbonylation sites were detected, resulting in the identification of respectively 34 and 77 different carbonylated amino acids. Thus, we demonstrated the application of a direct and sensitive method for studying protein carbonylation sites in complex protein extracts.

Oxidative damage in the Vesper mouse (Calomys laucha) exposed to a simulated oil spill-a multi-organ study.

Small wild mammals have been used to measure the damage caused by exposure to oil-contaminated soil, including deer mice. However, the study of toxic effects of crude oil using oxidative damage biomarkers in the wild rodent Calomys laucha (Vesper mouse) is absent. This investigation aimed to evaluate the effects of acute exposure to contaminated soil with different concentrations of crude oil (0, 1, 2, 4 and 8% w/w), simulating an accidental spill, using oxidative stress biomarkers in the liver, kidneys, lungs, testes, paw muscle, and lymphocytes of C. laucha. Animals exposed to the contaminated soil showed increases in lipid peroxidation and protein carbonylation at the highest exposure concentrations in most organ homogenates analyzed and also in blood cells, but responses to total antioxidant capacity were tissue-dependent. These results showed that acute exposure to oil-contaminated soil caused oxidative damage in C. laucha and indicate these small mammals may be susceptible to suffer the impacts of such contamination in its occurrence region, threatening the species' survival.

Metoprolol elicits neurobehavioral insufficiency and oxidative damage in nontarget Nauphoeta cinerea nymphs.

Metoprolol, a drug for hypertension and cardiovascular diseases, has become a contaminant of emerging concern because of its frequent detection in various environmental matrices globally. The dwindling in the biodiversity of useful insects owing to increasing presence of environmental chemicals is currently a great interest to the scientific community. In the current research, the toxicological impact of ecologically relevant concentrations of metoprolol at 0, 0.05, 0.1, 0.25, and 0.5 µg/L on Nauphoeta cinerea nymphs following exposure for 42 consecutive days was evaluated. The insects' behavior was analyzed with automated video-tracking software (ANY-maze, Stoelting Co, USA) while biochemical assays were done using the midgut, head and fat body. Metoprolol-exposed nymphs exhibited significant diminutions in the path efficiency, mobility time, distance traveled, body rotation, maximum speed and turn angle cum more episodes, and time of freezing. In addition, the heat maps and track plots confirmed the metoprolol-mediated wane in the exploratory and locomotor fitness of the insects. Compared with control, metoprolol exposure decreased acetylcholinesterase activity in insects head. Antioxidant enzymes activities and glutathione level were markedly decreased whereas indices of inflammation and oxidative injury to proteins and lipids were significantly increased in head, midgut and fat body of metoprolol-exposed insects. Taken together, metoprolol exposure induces neurobehavioral insufficiency and oxido-inflammatory injury in N. cinerea nymphs. These findings suggest the potential health effects of environmental contamination with metoprolol on ecologically and economically important nontarget insects.

Response to Cadmium in Silene vulgaris Ecotypes Is Distinctly Affected by Priming-Induced Changes in Oxidation Status of Macromolecules.

This study investigated the impact of several priming agents on metal-tolerant and sensitive Silene vulgaris ecotypes exposed to environmentally relevant cadmium dose. We analyzed how priming-induced changes in the level of lipid, protein, and DNA oxidation contribute to calamine (Cal) and non-calamine (N-Cal) ecotype response to Cd toxicity, and whether the oxidative modifications interrelate with Cd tolerance. In non-primed ecotypes, the levels of DNA and protein oxidation were similar whereas Cal Cd tolerance was manifested in reduced lipid peroxidation. In both ecotypes protective action of salicylic acid (SA) and nitric oxide (NO) priming was observed. SA stimulated growth and reduced lipid and DNA oxidation at most, while NO protected DNA from fragmentation. Priming with hydrogen peroxide reduced biomass and induced DNA oxidation. In N-Cal, priming diminished Cd accumulation and oxidative activity, whereas in Cal, it merely affected Cd uptake and induced protein carbonylation. The study showed that priming did not stimulate extra stress resistance in the tolerant ecotype but induced metabolic remodeling. In turn, the lack of adaptive tolerance made the sensitive ecotype more responsive to the benefits of the primed state. These findings could facilitate priming exploitation with a view of enhancing metallophyte and non-metallophyte suitability for phytoremediation and land revegetation.

Absence of endogenous carnosine synthesis does not increase protein carbonylation and advanced lipoxidation end products in brain, kidney or muscle.

Carnosine and other histidine-containing dipeptides are expected to be important anti-oxidants in vertebrates based on various in vitro and in vivo studies with exogenously administered carnosine or its precursor ß-alanine. To examine a possible anti-oxidant role of endogenous carnosine, mice lacking carnosine synthase (Carns1-/-) had been generated and were examined further in the present study. Protein carbonylation increased significantly between old (18 months) and aged (24 months) mice in brain and kidney but this was independent of the Carns1 genotype. Lipoxidation end products were not increased in 18-month-old Carns1-/- mice compared to controls. We also found no evidence for compensatory increase of anti-oxidant enzymes in Carns1-/- mice. To explore the effect of carnosine deficiency in a mouse model known to suffer from increased oxidative stress, Carns1 also was deleted in the type II diabetes model Leprdb/db mouse. In line with previous studies, malondialdehyde adducts were elevated in Leprdb/db mouse kidney, but there was no further increase by additional deficiency in Carns1. Furthermore, Leprdb/db mice lacking Carns1 were indistinguishable from conventional Leprdb/db mice with respect to fasting blood glucose and insulin levels. Taken together, Carns1 deficiency appears not to reinforce oxidative stress in old mice and there was no evidence for a compensatory upregulation of anti-oxidant enzymes. We conclude that the significance of the anti-oxidant activity of endogenously synthesized HCDs is limited in mice, suggesting that other functions of HCDs play a more important role.

Protein carbonylation in food and nutrition: a concise update.

Protein oxidation is a topic of indisputable scientific interest given the impact of oxidized proteins on food quality and safety. Carbonylation is regarded as one of the most notable post-translational modifications in proteins and yet, this reaction and its consequences are poorly understood. From a mechanistic perspective, primary protein carbonyls (i.e. α-aminoadipic and γ-glutamic semialdehydes) have been linked to radical-mediated oxidative stress, but recent studies emphasize the role alternative carbonylation pathways linked to the Maillard reaction. Secondary protein carbonyls are introduced in proteins via covalent linkage of lipid carbonyls (i.e. protein-bound malondialdehyde). The high reactivity of protein carbonyls in foods and other biological systems indicates the intricate chemistry of these species and urges further research to provide insight into these molecular mechanisms and pathways. In particular, protein carbonyls are involved in the formation of aberrant and dysfunctional protein aggregates, undergo further oxidation to yield carboxylic acids of biological relevance and establish interactions with other biomolecules such as oxidizing lipids and phytochemicals. From a methodological perspective, the routine dinitrophenylhydrazine (DNPH) method is criticized not only for the lack of accuracy and consistency but also authors typically perform a poor interpretation of DNPH results, which leads to misleading conclusions. From a practical perspective, the biological relevance of protein carbonyls in the field of food science and nutrition is still a topic of debate. Though the implication of carbonylation on impaired protein functionality and poor protein digestibility is generally recognized, the underlying mechanism of such connections requires further clarification. From a medical perspective, protein carbonyls are highlighted as markers of protein oxidation, oxidative stress and disease. Yet, the specific role of specific protein carbonyls in the onset of particular biological impairments needs further investigations. Recent studies indicates that regardless of the origin (in vivo or dietary) protein carbonyls may act as signalling molecules which activate not only the endogenous antioxidant defences but also implicate the immune system. The present paper concisely reviews the most recent advances in this topic to identify, when applicable, potential fields of interest for future studies.

Effect of a Ketogenic Diet on Oxidative Posttranslational Protein Modifications and Brain Homogenate Denaturation in the Kindling Model of Epilepsy in Mice.

This study focused on the ketogenic diet (KD) effects on oxidative posttranslational protein modification (PPM) as presumptive factors implicated in epileptogenesis. A 28-day of KD treatment was performed. The corneal kindling model of epileptogenesis was used. Four groups of adult male ICR mice (25-30 g) were randomized in standard rodent chow (SRC) group, KD-treatment group; SRC + kindling group; KD + kindling group (n = 10 each). Advanced oxidation protein products (AOPP) and protein carbonyl contents of brain homogenates together with differential scanning calorimetry (DSC) were evaluated. Two exothermic transitions (Exo1 and Exo2) were explored after deconvolution of the thermograms. Factor analysis was applied. The protective effect of KD in the kindling model was demonstrated with both decreased seizure score and increased seizure latency. KD significantly decreased glucose and increased ketone bodies (KB) in blood. Despite its antiseizure effect, the KD increased the AOPP level and the brain proteome's exothermic transitions, suggestive for qualitative modifications. The ratio of the two exothermic peaks (Exo2/Exo1) of the thermograms from the KD vs. SRC treated group differed more than twice (3.7 vs. 1.6). Kindling introduced the opposite effect, changing this ratio to 2.7 for the KD + kindling group. Kindling significantly increased glucose and KB in the blood whereas decreased the BW under the SRC treatment. Kindling decreased carbonyl proteins in the brain irrespectively of the diet. Further evaluations are needed to assess the nature of correspondence of calorimetric images of the brain homogenates with PPM.

Potential involvement of proline and flavonols in plant responses to ozone.

Ozone is considered to be a major phytotoxic pollutant. It is an oxidizing molecule with harmful effects that can affect human health and vegetation. Due to its phytotoxicity, it constitutes a threat to food security in a context of climate change. Proline accumulation is induced in response to numerous stresses and is assumed to be involved in plant antioxidant defense. We therefore addressed the question of the putative involvement of proline in plant ozone responses by analyzing the responses of two Arabidopsis mutants (obtained in the Col-0 genetic background) altered in proline metabolism and different ecotypes with various degrees of ozone sensitivity, to controlled ozone treatments. Among the mutants, the p5cs1 mutant plants accumulated less proline than the double prodh1xprodh2 (p1p2) mutants. Ozone treatments did not induce accumulation of proline in Col-0 nor in the mutant plants. However, the variation of the photosynthetic parameter Fv/Fm in the p1p2 mutant suggests a positive effect of proline. Proline accumulation induced by ozone was only observed in the most ozone-sensitive ecotypes, Cvi-0 and Ler. Contrary to our expectations, proline accumulation could not be correlated with variations in protein oxidation (carbonylation). On the other hand, flavonols content, measured here, using non-destructive methods, reflected exactly the genotypes ranking according to ozone sensitivity.

Increases in serum carbonylated protein levels of dogs with hypercortisolism.

Protein carbonylation is an irreversible and degenerative modification that can be used to evaluate oxidative stress caused by glucocorticoids. In this study, we focused on protein carbonylation in dogs with hypercortisolism (HC). Sera samples were collected from 14 dogs diagnosed with HC and treated with trilostane, 12 dogs with inflammatory diseases (disease control group), and eight clinically healthy dogs. When the carbonylated protein levels were detected by the immunoblot analysis, one band of approximately 40 kDa was predominantly increased in the dogs with HC. The band was identified as haptoglobin using the liquid chromatography tandem mass spectrometry method. Furthermore, haptoglobin immune reactivity was higher in the dogs with HC. Although the average protein carbonylation level of the HC group was not significantly different from that of the other groups, the carbonylation level was significantly higher for the poorly controlled HC cases than for the well-controlled HC group. Additionally, the primary culture of canine hepatocytes was used to clarify the direct effect of glucocorticoids on protein carbonylation in dog livers. Both the carbonylated protein and haptoglobin clearly increased after 72 h. These findings suggest that haptoglobin and its carbonylated form are increased with canine HC, and that the protein carbonylation ratio and/or haptoglobin level could be related to disease management. These factors could be useful as biomarkers for an oxidative stress reaction, at least in the liver, and for treatment monitoring of HC.

Naked mole-rats resist the accumulation of hypoxia-induced oxidative damage.

Naked mole-rats are among the few mammals with the ability to endure severe hypoxia. These unique rodents use metabolic rate depression along with various molecular mechanisms to successfully overcome the challenges of oxygen-limitation, which they experience in their underground borrows. While studies have reported that naked mole-rats exhibit inherently higher levels of oxidative damage across their lifespan as compared to mice, it has yet to be determined whether naked mole-rats are vulnerable to oxidative damage during periods of low oxygen exposure. To investigate this phenomenon, we examined cellular oxidative damage markers of macromolecules: DNA oxidation determined as 8-oxo-2'deoxyguanosine (8-OHdG8) levels, RNA oxidation as 8-hydroxyguanosine (8-OHG), protein carbonylation, and lipid peroxidation in normoxic (control), acute (4 h at 7% O2), and chronic (24 h at 7% O2) hypoxia-exposed naked mole-rats. Brain appears to be the most resilient to hypoxia-induced oxidative damage, with both brain and heart exhibiting enhanced antioxidant capacity during hypoxia. Levels of DNA and RNA oxidation were minimally changed in all tissues and no changes were observed in protein carbonylation. Most tissues experienced lipid peroxidation, with liver displaying a 9.6-fold increase during hypoxia. Concomitantly, levels of DNA damage repair proteins were dynamically regulated in a tissue-specific manner, with white adipose displaying a significant reduction during hypoxia. Our findings show that naked mole-rats largely avoid hypoxia-induced oxidative damage, possibly due to their high tolerance to redox stress, or to reduced oxidative requirements made possible during their hypometabolic response when oxygen supply is limited.

Hydrogen sulfide as a potent scavenger of toxicant acrolein.

Acrolein (ACR) is a metabolic byproduct in vivo and a ubiquitous environmental toxicant. It is implicated in the initiation and development of many diseases through multiple mechanisms, including the induction of oxidative stress. Currently, our understanding of the body defense mechanism against ACR toxicity is still limited. Given that hydrogen sulfide (H2S) has strong antioxidative actions and it shares several properties of ACR scavenger glutathione (GSH), we, therefore, tested whether H2S could be involved in ACR detoxification. Taking advantage of two cell lines that produced different levels of endogenous H2S, we found that the severity of ACR toxicity was reversely correlated with H2S-producing ability. In further support of the role of H2S, supplementing cells with exogenous H2S increased cell resistance to ACR, whereas inhibition of endogenous H2S sensitized cells to ACR. In vivo experiments showed that inhibition of endogenous H2S with CSE inhibitor markedly increased mouse susceptibility to the toxicity of cyclophosphamide and ACR, as evidenced by the increased mortality and worsened organ injury. Further analysis revealed that H2S directly reacted with ACR. It promoted ACR clearance and prevented ACR-initiated protein carbonylation. Collectively, this study characterized H2S as a presently unrecognized endogenous scavenger of ACR and suggested that H2S can be exploited to prevent and treat ACR-associated diseases.