Biochemistry and pathology of radical-mediated protein oxidation

Oxidative protein damage negatively affects protein-protein interaction: The case of KRAS-cRAF

Protein-protein interactions (PPIs) play crucial roles in cellular signaling, transmitting signals from the cell surface to its interior. One of the most important signaling cascades is the RAS-RAF-MEK-ERK pathway. This pathway is initiated by various upstream signaling reactions, including receptor tyrosine kinase (RTK) activation, and it controls many biological functions like cell proliferation, differentiation, and survival. Once RAS is activated, it binds RAF and relays the signal to downstream proteins. The RAS-binding domain (RBD) in RAF protein plays a crucial role in this process, facilitating the RAS-ERK pathway signaling. In this study, we explored the effect of oxidative stress induced by UV radiation on the KRAS-RBD interaction. Using the Split Intein-Mediated Protein Ligation (SIMPL) method, we assessed the impact of different UV doses on KRAS-RBD interactions and observed a disruption of this interaction at higher doses. UV-treated samples exhibited high levels of protein carbonylation, as detected by Oxime Blot and mass spectrometry (MS) analysis, indicating oxidative damage. The MS results provided detailed insights into specific carbonylation modifications on the KRAS protein. Our study demonstrates that protein oxidation and carbonylation can disrupt protein-protein interactions, specifically the KRAS/c-RAF interaction. These findings highlight the impact of oxidative stress on signaling pathways, such as those triggered by UV irradiation. A deeper understanding of these molecular changes may aid in developing therapies targeting diseases linked to oxidative stress, including cancer.

Effect of ozone oxidation on gastrointestinal digestion and absorption characteristics of silver carp (Hypophthalmichthys molitrix) surimi gels in vitro

To investigate the quality of different ozone-oxidized surimi gels and their in vitro digestion and absorption characteristics, surimi rinsed with different concentrations of ozonated water (0, 8, 26 mg/L) were prepared. Then, the degree of oxidation and gel structure of surimi were determined, the in vitro digestion and absorption of the gels were simulated, and the digestion and absorption products were analyzed by LC-MS/MS. The results showed that the quality of surimi gels was improved after proper ozone oxidation. After ozone water rinsing, the dry matter digestibility, peptide, and amino acid content increased, and the changes of all three were in line with the Logistic kinetic model (R2 = 0.95-0.99). Caco-2 cell absorption experiments showed that the absorption rate of peptides and amino acids decreased after ozone water rinsing. In summary, ozone oxidation can promote the digestion of surimi gels, but it also reduces the absorption of peptides and amino acids by Caco-2 cells. This study provides a reference for the application of ozone in the food field.

The effects of using sheep tail fat and cooking time on carboxymethyl-lysine formation and some quality characteristics of heat-treated sucuk

The study's aim was to determine the effect of using sheep tail fat (STF) on carboxymethyl-lysine (CML) content and other properties of heat-treated sucuk (HTS), a type of semi-dry fermented sausage. Three mixtures were prepared: 100% beef fat (BF), 50% BF + 50% STF, and 100% STF. After production (fermentation, heat treatment, and drying), the samples were cooked at 180°C for 0, 1, 3, and 5 min to determine the effect of cooking time on CML, thiobarbituric acid reactive substance (TBARS), total sulfhydryl, and carbonyl contents. The lowest pH value (5.50) was observed in the presence of STF. The most oleic acid (46.02%) was observed in the 100% STF group. The score of taste and general acceptability decreased with increasing STF. Using STF had no significant effect on TBARS, total sulfhydryl, carbonyl, or CML content. These parameters were affected by cooking time. The mean CML content increased from 55.77 to 72.90 μg/g after 5 min of cooking. CML correlated more strongly with TBARS than sulfhydryl or carbonyl.

Unveiling the metabolic landscape of pulmonary hypertension: insights from metabolomics

Pulmonary hypertension (PH) is regarded as cardiovascular disease with an extremely poor prognosis, primarily due to irreversible vascular remodeling. Despite decades of research progress, the absence of definitive curative therapies remains a critical challenge, leading to high mortality rates. Recent studies have shown that serious metabolic disorders generally exist in PH animal models and patients of PH, which may be the cause or results of the disease. It is imperative for future research to identify critical biomarkers of metabolic dysfunction in PH pathophysiology and to uncover metabolic targets that could enhance diagnostic and therapeutic strategies. Metabolomics offers a powerful tool for the comprehensive qualitative and quantitative analysis of metabolites within specific organisms or cells. On the basis of the findings of the metabolomics research on PH, this review summarizes the latest research progress on metabolic pathways involved in processes such as amino acid metabolism, carbohydrate metabolism, lipid metabolism, and nucleotide metabolism in the context of PH.

Role of Oxidative Stress in Periodontal Diseases

Periodontal disease, a significant worldwide health burden, is characterized by chronic inflammation and destruction of periodontal tissues, including the cementum, periodontal ligament (PDL), alveolar bone, and gingival tissue. Recent research has linked the development and progression of periodontal disease to oxidative stress. This study provides comprehensive explanations of the mechanisms behind oxidative stress in periodontal disease, with a focus on the generation of reactive oxygen species (ROS) and their effects on periodontal tissues. Oxidative stress triggers a number of detrimental reactions, including lipid peroxidation, protein oxidation, and damage to deoxyribonucleic acid (DNA). Alveolar bone resorption, connective tissue degradation, and periodontal inflammation are further conditions exacerbated by these processes. In addition, the delicate balance between antioxidants and oxidants is upset by oxidative stress, which impairs antioxidant defense systems and exacerbates periodontal tissue damage. This review highlights the negative effects of oxidative stress and enhances periodontal health outcomes.

The flavodiiron protein from Syntrophomonas wolfei has five domains and acts both as an NADH:O2 or an NADH:H2 O2 oxidoreductase

Flavodiiron proteins (FDPs) are a family of enzymes with a significant role in O2 /H2 O2 and/or NO detoxification through the reduction of these species to H2 O or N2 O, respectively. All FDPs contain a minimal catalytic unit of two identical subunits, each one having a metallo-β-lactamase-like domain harboring the catalytic diiron site, and a flavodoxin-like domain. However, more complex and diverse arrangements in terms of domains are found in this family, of which the class H enzymes are among the most complex. One of such FDPs is encoded in the genome of the anaerobic bacterium Syntrophomonas wolfei subsp. wolfei str. Goettingen G311. Besides the core domains, this protein is predicted to have three additional ones after the flavodoxin core domain: two short-chain rubredoxins and a NAD(P)H:rubredoxin oxidoreductase-like domain. This enzyme, FDP_H, was produced and characterized and the presence of the predicted cofactors was investigated by a set of biochemical and spectroscopic methodologies. Syntrophomonas wolfei FDP_H exhibited a remarkable O2 reduction activity with a kcat  = 52.0 ± 1.2 s-1 and a negligible NO reduction activity (~ 100 times lower than with O2 ), with NADH as an electron donor, that is, it is an oxygen-selective FDP. In addition, this enzyme showed the highest turnover value for H2 O2 reduction (kcat  = 19.1 ± 2.2 s-1 ) ever observed among FDPs. Kinetic studies of site-directed mutants of iron-binding cysteines at the two rubredoxin domains demonstrated the essential role of these centers since their absence leads to a significant decrease or even abolishment of O2 and H2 O2 reduction activities.

Sequestrase chaperones protect against oxidative stress-induced protein aggregation and [PSI+] prion formation

Misfolded proteins are usually refolded to their functional conformations or degraded by quality control mechanisms. When misfolded proteins evade quality control, they can be sequestered to specific sites within cells to prevent the potential dysfunction and toxicity that arises from protein aggregation. Btn2 and Hsp42 are compartment-specific sequestrases that play key roles in the assembly of these deposition sites. Their exact intracellular functions and substrates are not well defined, particularly since heat stress sensitivity is not observed in deletion mutants. We show here that Btn2 and Hsp42 are required for tolerance to oxidative stress conditions induced by exposure to hydrogen peroxide. Btn2 and Hsp42 act to sequester oxidized proteins into defined PQC sites following ROS exposure and their absence leads to an accumulation of protein aggregates. The toxicity of protein aggregate accumulation causes oxidant sensitivity in btn2 hsp42 sequestrase mutants since overexpression of the Hsp104 disaggregase rescues oxidant tolerance. We have identified the Sup35 translation termination factor as an in vivo sequestrase substrate and show that Btn2 and Hsp42 act to suppress oxidant-induced formation of the yeast [PSI+] prion, which is the amyloid form of Sup35. [PSI+] prion formation in sequestrase mutants does not require IPOD (insoluble protein deposit) localization which is the site where amyloids are thought to undergo fragmentation and seeding to propagate their heritable prion form. Instead, both amorphous and amyloid Sup35 aggregates are increased in btn2 hsp42 mutants consistent with the idea that prion formation occurs at multiple intracellular sites during oxidative stress conditions in the absence of sequestrase activity. Taken together, our data identify protein sequestration as a key antioxidant defence mechanism that functions to mitigate the damaging consequences of protein oxidation-induced aggregation.

The mitochondria‒paraspeckle axis regulates the survival of transplanted stem cells under oxidative stress conditions

Rationale: Stem cell-based therapies have emerged as promising tools for tissue engineering and regenerative medicine, but their therapeutic efficacy is largely limited by the oxidative stress-induced loss of transplanted cells at injured tissue sites. To address this issue, we aimed to explore the underlying mechanism and protective strategy of ROS-induced MSC loss. Methods: Changes in TFAM (mitochondrial transcription factor A) signaling, mitochondrial function, DNA damage, apoptosis and senescence in MSCs under oxidative stress conditions were assessed using real-time PCR, western blotting and RNA sequencing, etc. The impact of TFAM or lncRNA nuclear paraspeckle assembly transcript 1 (NEAT1) knockdown or overexpression on mitochondrial function, DNA damage repair, apoptosis and senescence in MSCs was also analyzed. The effect of mitochondrion-targeted antioxidant (Mito-TEMPO) on the survival of transplanted MSCs was evaluated in a mouse model of renal ischemia/reperfusion (I/R) injury. Results: Mitochondrial ROS (mtROS) bursts caused defects in TFAM signaling and overall mitochondrial function, which further impaired NEAT1 expression and its mediated paraspeckle formation and DNA repair pathways in MSCs, thereby jointly promoting MSC senescence and death under oxidative stress. In contrast, targeted inhibition of the mtROS bursts is a sufficient strategy for attenuating early transplanted MSC loss at injured tissue sites, and coadministration of Mito-TEMPO improved the local retention of transplanted MSCs and reduced oxidative injury in ischemic kidneys. Conclusions: This study identified the critical role of the mitochondria‒paraspeckle axis in regulating cell survival and may provide insights into developing advanced stem cell therapies for tissue engineering and regenerative medicine.

An Overview of Reactive Oxygen Species Damage Occurring during In Vitro Bovine Oocyte and Embryo Development and the Efficacy of Antioxidant Use to Limit These Adverse Effects

The in vitro production (IVP) of bovine embryos has gained popularity worldwide and in recent years and its use for producing embryos from genetically elite heifers and cows has surpassed the use of conventional superovulation-based embryo production schemes. There are, however, several issues with the IVP of embryos that remain unresolved. One limitation of special concern is the low efficiency of the IVP of embryos. Exposure to reactive oxygen species (ROS) is one reason why the production of embryos with IVP is diminished. These highly reactive molecules are generated in small amounts through normal cellular metabolism, but their abundances increase in embryo culture because of oocyte and embryo exposure to temperature fluctuations, light exposure, pH changes, atmospheric oxygen tension, suboptimal culture media formulations, and cryopreservation. When uncontrolled, ROS produce detrimental effects on the structure and function of genomic and mitochondrial DNA, alter DNA methylation, increase lipid membrane damage, and modify protein activity. Several intrinsic enzymatic pathways control ROS abundance and damage, and antioxidants react with and reduce the reactive potential of ROS. This review will focus on exploring the efficiency of supplementing several of these antioxidant molecules on oocyte maturation, sperm viability, fertilization, and embryo culture.

From amino-acid to disease: the effects of oxidation on actin-myosin interactions in muscle

Actin-myosin interactions form the basis of the force-producing contraction cycle within the sarcomere, serving as the primary mechanism for muscle contraction. Post-translational modifications, such as oxidation, have a considerable impact on the mechanics of these interactions. Considering their widespread occurrence, the explicit contributions of these modifications to muscle function remain an active field of research. In this review, we aim to provide a comprehensive overview of the basic mechanics of the actin-myosin complex and elucidate the extent to which oxidation influences the contractile cycle and various mechanical characteristics of this complex at the single-molecule, myofibrillar and whole-muscle levels. We place particular focus on amino acids shown to be vulnerable to oxidation in actin, myosin, and some of their binding partners. Additionally, we highlight the differences between in vitro environments, where oxidation is controlled and limited to actin and myosin and myofibrillar or whole muscle environments, to foster a better understanding of oxidative modification in muscle. Thus, this review seeks to encompass a broad range of studies, aiming to lay out the multi layered effects of oxidation in in vitro and in vivo environments, with brief mention of clinical muscular disorders associated with oxidative stress.

Diels-Alder Photoclick Patterning of Extracellular Matrix for Spatially Controlled Cell Behaviors

Strategies that mimic the spatial complexity of natural tissues can provide cellular scaffolds to probe fundamental questions in cell biology and offer new materials for regenerative medicine. Here, the authors demonstrate a light-guided patterning platform that uses natural engineered extracellular matrix (ECM) proteins as a substrate to program cellular behaviors. A photocaged diene which undergoes Diels-Alder-based click chemistry upon uncaging with 365 nm light is utilized. By interfacing with commercially available maleimide dienophiles, patterning of common ECM proteins (collagen, fibronectin Matrigel, laminin) with readily purchased functional small molecules and growth factors is achieved. Finally, the use of this platform to spatially control ERK activity and migration in mammalian cells is highlighted, demonstrating programmable cell behavior through patterned chemical modification of natural ECM.

Phenotypic molecular features of long-lived animal species

One of the challenges facing science/biology today is uncovering the molecular bases that support and determine animal and human longevity. Nature, in offering a diversity of animal species that differ in longevity by more than 5 orders of magnitude, is the best 'experimental laboratory' to achieve this aim. Mammals, in particular, can differ by more than 200-fold in longevity. For this reason, most of the available evidence on this topic derives from comparative physiology studies. But why can human beings, for instance, reach 120 years whereas rats only last at best 4 years? How does nature change the longevity of species? Longevity is a species-specific feature resulting from an evolutionary process. Long-lived animal species, including humans, show adaptations at all levels of biological organization, from metabolites to genome, supported by signaling and regulatory networks. The structural and functional features that define a long-lived species may suggest that longevity is a programmed biological property.

Tetrahydrobiopterin as a Trigger for Vitiligo: Phototransformation during UV Irradiation

Vitiligo is a type of hypomelanosis. Tetrahydrobiopterin (H4Bip), the coenzyme of the initial stage of melanogenesis, appears to be a trigger for vitiligo. H4Bip is present in vitiligo in 3-5-fold excess and causes oxidative stress by triggering an autocatalytic cycle of excess hydrogen peroxide synthesis. Using quantum-chemical calculations, we have evaluated the possibility of H4Bip reactions occurring in the dark and under ultraviolet (UV) irradiation, including the formation of dihydropterin dimers. In order to simulate the oxidative stress, oxidative modification of human serum albumin (HSA) has been carried out in the presence of excessive H4Bip using the fluorescence method. The fraction of oxidized protein (FOP) has been calculated. It has been established that there is a strong oxidative modification of amino acids chromophores (tryptophan and tyrosine) in the protein (FOP 0.64). Under UV irradiation of the system (HSA + H4Bip), FOP is reduced to 0.39. Apparently, a part of H4Bip transforms into dihydropterin dimers and does not participate in the oxidative modification of the protein. The data on oxidative modification of HSA are consistent with dynamic light scattering: H4Bip promotes HSA aggregation with the formation of particles with a hydrodynamic radius Rh ≥ 2000 nm, which can become immunogenic.

Blood biochemical changes upon subclinical intramammary infection and inflammation in Holstein cattle

The aim of this study was to investigate the associations between subclinical intramammary infection (IMI) from different pathogens combined with inflammation status and a set of blood biochemical traits including energy-related metabolites, indicators of liver function or hepatic damage, oxidative stress, inflammation, innate immunity, and mineral status in 349 lactating Holstein cows. Data were analyzed with a linear model including the following fixed class effects: days in milk, parity, herd, somatic cell count (SCC), bacteriological status (positive and negative), and the SCC × bacteriological status interaction. Several metabolites had significant associations with subclinical IMI or SCC. Increased SCC was associated with a linear decrease in cholesterol concentrations which ranged from -2% for the class ≥50,000 and <200,000 cells/mL to -11% for the SCC class ≥400,000 cells/mL compared with the SCC class <50,000 cells/mL. A positive bacteriological result was associated with an increase in bilirubin (+24%), paraoxonase (+11%), the ratio paraoxonase/cholesterol (+9%), and advanced oxidation protein product concentration (+23%). Increased SCC were associated with a linear decrease in ferric reducing antioxidant power concentrations ranging from -3% for the class ≥50,000 and <200,000 cells/mL to -9% for the SCC class ≥400,000 cells/mL (respect to the SCC class <50,000 cells/mL). A positive bacteriological result was associated with an increase in haptoglobin concentrations (+19%). Increased SCC were also associated with a linear increase in haptoglobin concentrations, which ranged from +24% for the class ≥50,000 and <200,000 cells/mL (0.31 g/L) to +82% for the SCC class ≥400,000 cells/mL (0.45 g/L), with respect to the SCC class <50,000 cells/mL (0.25 g/L). Increased SCC were associated with a linear increase in ceruloplasmin concentrations (+15% for SCC ≥50,000 cells/mL). The observed changes in blood biochemical markers, mainly acute phase proteins and oxidative stress markers, suggest that cows with subclinical IMI may experience a systemic involvement.

Metabolic Regulation of Copper Toxicity during Marine Mussel Embryogenesis

The development of new tools for assessing the health of cultured shellfish larvae is crucial for aquaculture industries to develop and refine hatchery methodologies. We established a large-volume ecotoxicology/health stressor trial, exposing mussel (Perna canaliculus) embryos to copper in the presence of ethylenediaminetetraacetic acid (EDTA). GC/MS-based metabolomics was applied to identify potential biomarkers for monitoring embryonic/larval health and to characterise mechanisms of metal toxicity. Cellular viability, developmental abnormalities, larval behaviour, mortality, and a targeted analysis of proteins involved in the regulation of reactive oxygen species were simultaneously evaluated to provide a complementary framework for interpretative purposes and authenticate the metabolomics data. Trace metal analysis and speciation modelling verified EDTA as an effective copper chelator. Toxicity thresholds for P. canaliculus were low, with 10% developmental abnormalities in D-stage larvae being recorded upon exposure to 1.10 μg·L-1 bioavailable copper for 66 h. Sublethal levels of bioavailable copper (0.04 and 1.10 μg·L-1) caused coordinated fluctuations in metabolite profiles, which were dependent on development stage, treatment level, and exposure duration. Larvae appeared to successfully employ various mechanisms involving the biosynthesis of antioxidants and a restructuring of energy-related metabolism to alleviate the toxic effects of copper on cells and developing tissues. These results suggest that regulation of trace metal-induced toxicity is tightly linked with metabolism during the early ontogenic development of marine mussels. Lethal-level bioavailable copper (50.3 μg·L-1) caused severe metabolic dysregulation after 3 h of exposure, which worsened with time, substantially delayed embryonic development, induced critical oxidative damage, initiated the apoptotic pathway, and resulted in cell/organism death shortly after 18 h of exposure. Metabolite profiling is a useful approach to (1) assess the health status of marine invertebrate embryos and larvae, (2) detect early warning biomarkers for trace metal contamination, and (3) identify novel regulatory mechanisms of copper-induced toxicity.

Characterization and Mechanism of Gel Deterioration of Egg Yolk Powder during Storage

Egg yolk forms have several health and industrial applications, but their storage characteristics and gel mechanisms have not been thoroughly studied. In order to investigate the relationship between the changes in structure and properties of egg yolk gel and egg yolk powder during storage, in this paper, egg yolk powder was stored at 37 °C for 0, 1, 3, and 6 months in an accelerated storage experiment, and the influence of storage time on the gel properties of egg yolk powder was analyzed. The results showed that the contents of protein carbonylation and sulfhydryl in the yolk decreased gradually with the extension of storage time. Circular dichroism and fluorescence spectra showed that the ordered structure and structural stability of egg yolk proteins decreased gradually. Oxidation led to the formation of intermolecular crosslinking in the egg yolk proteins and oxidized aggregates, resulting in a decrease in surface hydrophobicity, which affected the gel properties of the egg yolk powder after rehydration, resulting in the phenomenon of lipid migration and gel degradation. The results provide a theoretical basis for improving egg yolk powder's overall quality and storage stability.

Evaluation of Primary DNA Damage in Young Healthy Females Based on Their Dietary Preferences

DNA damage is known to be associated with many adverse health outcomes, including cancer and chronic diseases, but also with the process of aging. Empirical evidence has shown that environmental exposures, such as certain lifestyle factors, can affect a variety of health-related biomarkers and also impact the stability of DNA through the upregulation of the antioxidant defense system and alteration of its repair capacity. In addition to exercising, diet is an important lifestyle factor that can affect the development of a variety of chronic diseases and growing evidence suggests that plant-based diets, including vegetarianism, may promote health, longevity, and well-being. Therefore, we aimed to assess the primary DNA damage in 32 young healthy females from Zagreb, Croatia, based on their dietary preferences. The participants were divided into two groups: vegetarians and non-vegetarians, where the non-vegetarian group was further divided into omnivores (traditional mixed diet) and pescatarians (consumption of fish and seafood). According to statistical analysis, the DNA damage measured in whole blood cells expressed as the % tail DNA was significantly (p < 0.05) higher in vegetarians (3.6 ± 1.1%) compared to non-vegetarians (2.8 ± 1.0%). When further dividing the participants into specific sub-groups, lower DNA damage was observed amongst omnivorous subjects (3.2 ± 0.8%) compared to vegetarians, with the lowest DNA damage found in females practicing a pescatarian diet (2.4 ± 1.1%). Although a vegetarian diet can lead to a higher intake of specific vitamins and micronutrients, it can also lead to a deficiency of iron, calcium, and total proteins, which may affect genome stability and induce oxidative stress. Even though our results have shown that the pescatarian diet would be more beneficial in terms of maintaining DNA integrity, further research should be carried out to assess how specific dietary preferences affect DNA integrity on a larger scale.

Identification and characterisation of the tegument-expressed aldehyde dehydrogenase SmALDH_312 of Schistosoma mansoni, a target of disulfiram

Schistosomiasis is an infectious disease caused by blood flukes of the genus Schistosoma and affects approximately 200 million people worldwide. Since Praziquantel (PZQ) is the only drug for schistosomiasis, alternatives are needed. By a biochemical approach, we identified a tegumentally expressed aldehyde dehydrogenase (ALDH) of S. mansoni, SmALDH_312. Molecular analyses of adult parasites showed Smaldh_312 transcripts in both genders and different tissues. Physiological and cell-biological experiments exhibited detrimental effects of the drug disulfiram (DSF), a known ALDH inhibitor, on larval and adult schistosomes in vitro. DSF also reduced stem-cell proliferation and caused severe tegument damage in treated worms. In silico-modelling of SmALDH_312 and docking analyses predicted DSF binding, which we finally confirmed by enzyme assays with recombinant SmALDH_312. Furthermore, we identified compounds of the Medicine for Malaria Venture (MMV) pathogen box inhibiting SmALDH_312 activity. Our findings represent a promising starting point for further development towards new drugs for schistosomiasis.

Moderate Protein Oxidation Improves Bovine Myofibril Digestibility by Releasing Peptides in the S2 Region of Myosin: A Peptidomics Perspective

This study aimed to investigate the influence of protein oxidation on the digestive properties of beef myofibrillar protein (MP). MP was treated with a hydroxyl radical-generating system containing various concentrations of H₂O₂. The increased content in a free sulfhydryl group and surface hydrophobicity indicated that oxidation treatment with 1 mM H₂O₂ induced unfolding of MP. Reducing and nonreducing SDS-PAGE results suggested that 10 mM H₂O₂ oxidation treatment resulted in aggregation of MP; meanwhile, the disulfide bond was the major covalent bond involved in aggregation. Peptidomics showed that peptides in the digestion products of MP were mainly derived from myosin tail. Moderate oxidation (1 mM H₂O₂) facilitated the release of peptide in the rod portion (S2) of myosin, whereas excessive oxidation (10 mM H₂O₂) inhibited peptide release in the light meromyosin region. This work presents insightful information for the crucial impact of oxidation on meat protein digestibility from the peptidomics perspective.

Identification of the BcLEA Gene Family and Functional Analysis of the BcLEA73 Gene in Wucai (Brassica campestris L.)

Late embryogenesis abundant (LEA) proteins are important developmental proteins in the response of plants to abiotic stress. In our previous study, BcLEA73 was differentially expressed under low-temperature stress. Herein, we combined bioinformatics analysis, subcellular localization, expression assays, and stress experiments (including salt, drought, and osmotic stress) to identify and analyze the BcLEA gene family. Gene cloning and functional analysis of BcLEA73 were performed in tobacco and Arabidopsis. Based on the sequence homology and the available conservative motif, 82 BrLEA gene family members were identified and were divided into eight subfamilies in the genome-wide database of Chinese cabbage. The analysis showed that the BrLEA73 gene was located on chromosome A09 and belonged to the LEA_6 subfamily. Quantitative real-time PCR analysis indicated that the BcLEA genes were differentially expressed to varying degrees in the roots, stems, leaves, and petioles of Wucai. The overexpressed BcLEA73 transgenic plants exhibited no significant differences in root length and seed germination rates compared to the wild-type (WT) plants under control conditions. Under salt and osmotic stress treatment, the root length and seed germination rates of the BcLEA73-OE strain were significantly greater than those of WT plants. Under salt stress, the total antioxidant capacity (T-AOC) of the BcLEA73-OE lines increased significantly, and the relative conductivity, (REL), hydrogen peroxide (H2O2) content, and superoxide anion (O2-) production rate decreased significantly. Under drought treatment, the survival rate of the BcLEA73-OE lines was significantly higher than that of WT plants. These results showed that the BcLEA73 gene of Wucai functions in enhancing the tolerance of plants to salt, drought, and osmotic stress. This study provides a theoretical basis to explore the relevant functions of the BcLEA gene family members of Wucai.

Responses of Salmonella biofilms to oxidizing biocides: Evidence of spatial clustering

The spatial organization of biofilm bacterial communities can be influenced by several factors, including growth conditions and challenge with antimicrobials. Differential survival of clusters of cells within biofilms has been observed. In this work, we present a variety of methods to identify, quantify and statistically analyse clusters of live cells from images of two Salmonella strains with differential biofilm forming capacity exposed to three oxidizing biocides. With a support vector machine approach, we showed spatial separation between the two strains, and, using statistical testing and high-performance computing (HPC), we determined conditions which possess an inherent cluster structure. Our results indicate that there is a relationship between biocide potency and inherent biofilm formation capacity with the tendency to select for spatial clusters of survivors. There was no relationship between positions of clusters of live or dead cells within stressed biofilms. This work identifies an approach to robustly quantify clusters of physiologically distinct cells within biofilms and suggests work to understand how clusters form and survive is needed. SIGNIFICANCE STATEMENT: Control of biofilm growth remains a major challenge and there is considerable uncertainty about how bacteria respond to disinfection within a biofilm and how clustering of cells impacts survival. We have developed a methodological approach to identify and statistically analyse clusters of surviving cells in biofilms after biocide challenge. This approach can be used to understand bacterial behaviour within biofilms under stress and is widely applicable.

The Neuroprotective Potentiality of Flavonoids on Alzheimer's Disease

Alzheimer's disease (AD), due to its spread, has become a global health priority, and is characterized by senile dementia and progressive disability. The main cause of AD and other neurodegenerations (Huntington, Parkinson, Amyotrophic Lateral Sclerosis) are aggregated protein accumulation and oxidative damage. Recent research on secondary metabolites of plants such as polyphenols demonstrated that they may slow the progression of AD. The flavonoids' mechanism of action in AD involved the inhibition of acetylcholinesterase, butyrylcholinesterase, Tau protein aggregation, β-secretase, oxidative stress, inflammation, and apoptosis through modulation of signaling pathways which are implicated in cognitive and neuroprotective functions, such as ERK, PI3-kinase/Akt, NFKB, MAPKs, and endogenous antioxidant enzymatic systems. This review focuses on flavonoids and their role in AD, in terms of therapeutic potentiality for human health, antioxidant potential, and specific AD molecular targets.

Assessment of Protective Effects of Carvacrol on Haloperidol-Induced Oxidative Stress and Genotoxicity in Human Peripheral Blood Lymphocytes

Haloperidol is a first-generation antipsychotic drug that has several indications in a wide range of mental conditions. The extensive prescription of haloperidol is correlated with some less-known adverse effects such as genotoxicity. Carvacrol is a monoterpenoid mainly found in oregano and thyme. It has the potential to scavenge free radicals in addition to increasing antioxidant defense enzyme activities and glutathione levels. In this study, we attempted to explore the possible potential of haloperidol in inducing genotoxicity in human peripheral lymphocytes as well as the protective role of carvacrol against this effect. The lymphocytes were divided into separate groups as follows: control group (cosolvent and NS); carvacrol group (5 μM); haloperidol group (25, 50, and 100 ng/ml); haloperidol (25, 50, and 100 ng/ml) + carvacrol (5 μM); positive control (0.8 μg/ml Cisplatin). After 24 hours of treatment, we conducted a cytokinesis-Block micronucleus test and an alkaline comet assay in order to determine genetic damage. Additionally, we measured glutathione and MDA levels as the biomarkers associated with oxidative stress. Significant increases in the levels of genotoxicity biomarkers (micronucleus frequency, DNA percentage in tail and tail moment) were observed in haloperidol-treated cells. The result of our oxidative stress tests also demonstrated that haloperidol had the potential to induce oxidative stress via reducing the levels of glutathione and increasing lipid peroxidation. Treatment with carvacrol significantly decreased the genotoxic events. It can be presumed that the induction of oxidative stress by haloperidol is the critical event associated with haloperidol-mediated genotoxicity. Therefore, using carvacrol as a natural antioxidant protected human lymphocytes against haloperidol genetic damage.

Effect of Malondialdehyde-Induced Oxidation Modification on Physicochemical Changes and Gel Characteristics of Duck Myofibrillar Proteins

This paper focuses on the effect of malondialdehyde-induced oxidative modification (MiOM) on the gel properties of duck myofibrillar proteins (DMPs). DMPs were first prepared and treated with oxidative modification at different concentrations of malondialdehyde (0, 0.5, 2.5, 5.0, and 10.0 mmol/L). The physicochemical changes (carbonyl content and free thiol content) and gel properties (gel whiteness, gel strength, water holding capacity, rheological properties, and microstructural properties) were then investigated. The results showed that the content of protein carbonyl content increased with increasing MDA oxidation (p < 0.05), while the free thiol content decreased significantly (p < 0.05). Meanwhile, there was a significant decrease in gel whiteness; the gel strength and water-holding capacity of protein gels increased significantly under a low oxidation concentration of MDA (0−5 mmol/L); however, the gel strength decreased under a high oxidation concentration (10 mmol/L) compared with other groups (0.5−5 mmol/L). The storage modulus and loss modulus of oxidized DMPs also increased with increasing concentrations at a low concentration of MDA (0−5 mmol/L); moreover, microstructural analysis confirmed that the gels oxidized at low concentrations (0.5−5 mmol/L) were more compact and homogeneous in terms of pore size compared to the high concentration or blank group. In conclusion, moderate oxidation of malondialdehyde was beneficial to improve the gel properties of duck; however, excessive oxidation was detrimental to the formation of dense structured gels.

Mechanoresponsive diselenide-crosslinked microgels with programmed ultrasound-triggered degradation and radical scavenging ability for protein protection

In the context of controlled delivery and release, proteins constitute a delicate class of cargo requiring advanced delivery platforms and protection. We here show that mechanoresponsive diselenide-crosslinked microgels undergo controlled ultrasound-triggered degradation in aqueous solution for the release of proteins. Simultaneously, the proteins are protected from chemical and conformational damage by the microgels, which disintegrate to water-soluble polymer chains upon sonication. The degradation process is controlled by the amount of diselenide crosslinks, the temperature, and the sonication amplitude. We demonstrate that the ultrasound-mediated cleavage of diselenide bonds in these microgels facilitates the release and activates latent functionality preventing the oxidation and denaturation of the encapsulated proteins (cytochrome C and myoglobin) opening new application possibilities in the targeted delivery of biomacromolecules.

Head-to-Head Comparison of Oxidative Stress Biomarkers for All-Cause Mortality in Hemodialysis Patients

Oxidative stress (OS) presents even in the early chronic kidney disease (CKD) stage and is exacerbated in patients with end-stage renal disease (ESRD) undergoing maintenance hemodialysis (MHD). There is still a debate over the association between oxidative stress and mortality. Our study aims to compare head-to-head the prognostic value of different oxidative markers for all-cause mortality in hemodialysis (HD) patients. We thus enrolled 347 patients on HD in this prospective study. Four OS biomarkers were measured (carbonyl proteins, myeloperoxidase (MPO), advanced oxidation protein products (AOPPs), and oxidized low-density lipoprotein (ox-LDL)). During the 60-month follow-up period, 9 patients have been lost to follow-up and 168 (48.4%) patients died. Concerning the oxidative stress (ox-stress) byproducts, carbonyl proteins were lower in survivors (105.40 ng/mL (IQR 81.30−147.85) versus 129.65 ng/mL (IQR 93.20−180.33); p < 0.001), with similar results for male patients (103.70 ng/mL (IQR 76.90−153.33) versus 134.55 ng/mL (IQR 93.95−178.68); p = 0.0014). However, there are no significant differences in MPO, AOPP, and ox-LDL between the two groups. Kaplan−Meier survival analysis indicated that patients in the higher carbonyl proteins concentration (>117.85 ng/mL group) had a significantly lower survival rate (log-rank test, p < 0.001). Univariate Cox regression analysis showed a positive correlation between carbonyl proteins and all-cause mortality in the higher and lower halves. Even after adjustment for conventional risk factors, it remained a statistically significant predictor of an increased risk of death in MHD. Univariate Cox regression analysis of MPO showed that continuous MPO and Log MPO were significantly associated with all-cause mortality, except for binary MPO (divided according to the median of MPO). Multivariate Cox analysis for MPO showed that the mortality prediction remains significant after adjusting for multiple factors. In conclusion, not all ox-stress biomarkers predict all-cause mortality in HD patients to a similar extent. In the present study, carbonyl proteins and MPO are independent predictors of all-cause mortality in HD patients, whereas AOPPs and oxLDL are clearly not associated with all-cause mortality in HD patients.

Crosstalk between Sirtuins and Nrf2: SIRT1 activators as emerging treatment for diabetic neuropathy

About 50% of the diabetic patients worldwide suffer from Diabetic peripheral neuropathy (DPN) which is characterized by chronic pain and loss of sensation, frequent foot ulcerations, and risk for amputation. Numerous factors like hyperglycemia, oxidative stress (OS), impaired glucose signaling, inflammatory responses, neuronal cell death are known to be the various mechanisms underlying DACD and DPN. Development of tolerance, insufficient and inadequate relief and potential toxicity of classical antinociceptives still remains a challenge in the clinical setting. Therefore, there is an emerging need for novel treatments which are both without any potential side effects as well as which focus more on the pathophysiological mechanisms underlying the disease. Also, sirtuins are known to deacetylate Nrf2 and contribute to its action of reducing ROS by generation of anti-oxidant enzymes. Therefore, targeting sirtuins could be a favourable therapeutic strategy to treat diabetic neuropathy by reducing ROS and thereby alleviating OS in DPN. In the present review, we outline the potential use of SIRT1 activators as therapeutic alternatives in treating DPN. We have tried to highlight how sirtuins are interlinked with Nrf2 and NF-κB and put forth how SIRT activators could serve as potential therapy for DPN.

Group II truncated haemoglobin YjbI prevents reactive oxygen species-induced protein aggregation in Bacillus subtilis

Oxidative stress-mediated formation of protein hydroperoxides can induce irreversible fragmentation of the peptide backbone and accumulation of cross-linked protein aggregates, leading to cellular toxicity, dysfunction, and death. However, how bacteria protect themselves from damages caused by protein hydroperoxidation is unknown. Here, we show that YjbI, a group II truncated haemoglobin from Bacillus subtilis, prevents oxidative aggregation of cell-surface proteins by its protein hydroperoxide peroxidase-like activity, which removes hydroperoxide groups from oxidised proteins. Disruption of the yjbI gene in B. subtilis lowered biofilm water repellence, which associated with the cross-linked aggregation of the biofilm matrix protein TasA. YjbI was localised to the cell surface or the biofilm matrix, and the sensitivity of planktonically grown cells to generators of reactive oxygen species was significantly increased upon yjbI disruption, suggesting that YjbI pleiotropically protects labile cell-surface proteins from oxidative damage. YjbI removed hydroperoxide residues from the model oxidised protein substrate bovine serum albumin and biofilm component TasA, preventing oxidative aggregation in vitro. Furthermore, the replacement of Tyr⁶³ near the haem of YjbI with phenylalanine resulted in the loss of its protein peroxidase-like activity, and the mutant gene failed to rescue biofilm water repellency and resistance to oxidative stress induced by hypochlorous acid in the yjbI-deficient strain. These findings provide new insights into the role of truncated haemoglobin and the importance of hydroperoxide removal from proteins in the survival of aerobic bacteria.

Stress-Induced Premature Senescence Related to Oxidative Stress in the Developmental Programming of Nonalcoholic Fatty Liver Disease in a Rat Model of Intrauterine Growth Restriction

Metabolic syndrome (MetS) refers to cardiometabolic risk factors, such as visceral obesity, dyslipidemia, hyperglycemia/insulin resistance, arterial hypertension and non-alcoholic fatty liver disease (NAFLD). Individuals born after intrauterine growth restriction (IUGR) are particularly at risk of developing metabolic/hepatic disorders later in life. Oxidative stress and cellular senescence have been associated with MetS and are observed in infants born following IUGR. However, whether these mechanisms could be particularly associated with the development of NAFLD in these individuals is still unknown. IUGR was induced in rats by a maternal low-protein diet during gestation versus. a control (CTRL) diet. In six-month-old offspring, we observed an increased visceral fat mass, glucose intolerance, and hepatic alterations (increased transaminase levels, triglyceride and neutral lipid deposit) in male rats with induced IUGR compared with the CTRL males; no differences were found in females. In IUGR male livers, we identified some markers of stress-induced premature senescence (SIPS) (lipofuscin deposit, increased protein expression of p21WAF, p16INK4a and Acp53, but decreased pRb/Rb ratio, foxo-1 and sirtuin-1 protein and mRNA expression) associated with oxidative stress (higher superoxide anion levels, DNA damages, decreased Cu/Zn SOD, increased catalase protein expression, increased nfe2 and decreased keap1 mRNA expression). Impaired lipogenesis pathways (decreased pAMPK/AMPK ratio, increased pAKT/AKT ratio, SREBP1 and PPARγ protein expression) were also observed in IUGR male livers. At birth, no differences were observed in liver histology, markers of SIPS and oxidative stress between CTRL and IUGR males. These data demonstrate that the livers of IUGR males at adulthood display SIPS and impaired liver structure and function related to oxidative stress and allow the identification of specific therapeutic strategies to limit or prevent adverse consequences of IUGR, particularly metabolic and hepatic disorders.

Changes in Textural Quality and Water Retention of Spiced Beef under Ultrasound-Assisted Sous-Vide Cooking and Its Possible Mechanisms

The present study investigated the effects of ultrasound (28 kHz, 60 W at 71 °C for 37 min) combined with sous-vide cooking (at 71 °C for 40, 60, 80, 100, 120 min) on the textural quality, water distribution, and protein characteristics of spiced beef. Results showed that the spiced beef treated with conventional cooking (CT) had the highest cooking loss (41.31%), but the lowest value of shear force (8.13 N), hardness (55.66 N), springiness (3.98 mm), and chewiness (64.36 mJ) compared to ultrasound-assisted sous-vide (USV) and sous-vide cooking (SV) groups. Compared with long-time thermal treatment, USV heating within 100 min enhanced the water retention of spiced beef by maintaining the lower values of cooking loss (16.64~25.76%), T₂ relaxation time (242.79~281.19 ms), and free water content (0.16~2.56%), as evident by the intact muscle fibers. Moreover, the USV group had relatively lower carbonyl content, but higher sulfhydryl content compared to CT and SV groups. More protein bands coupled with a minor transformation from α-helixes to β-turns and random coils occurred in USV40~USV80. In conclusion, these results indicated that USV treatment within 100 min positively affected the textural quality and water retention of spiced beef by moderate protein oxidation.

Role of Oxidative Stress in the Pathogenesis of Atherothrombotic Diseases

Oxidative stress is generated by the imbalance between reactive oxygen species (ROS) formation and antioxidant scavenger system’s activity. Increased ROS, such as superoxide anion, hydrogen peroxide, hydroxyl radical and peroxynitrite, likely contribute to the development and complications of atherosclerotic cardiovascular diseases (ASCVD). In genetically modified mouse models of atherosclerosis, the overexpression of ROS-generating enzymes and uncontrolled ROS formation appear to be associated with accelerated atherosclerosis. Conversely, the overexpression of ROS scavenger systems reduces or stabilizes atherosclerotic lesions, depending on the genetic background of the mouse model. In humans, higher levels of circulating biomarkers derived from the oxidation of lipids (8-epi-prostaglandin F_2α, and malondialdehyde), as well as proteins (oxidized low-density lipoprotein, nitrotyrosine, protein carbonyls, advanced glycation end-products), are increased in conditions of high cardiovascular risk or overt ASCVD, and some oxidation biomarkers have been reported as independent predictors of ASCVD in large observational cohorts. In animal models, antioxidant supplementation with melatonin, resveratrol, Vitamin E, stevioside, acacetin and n-polyunsaturated fatty acids reduced ROS and attenuated atherosclerotic lesions. However, in humans, evidence from large, placebo-controlled, randomized trials or prospective studies failed to show any athero-protective effect of antioxidant supplementation with different compounds in different CV settings. However, the chronic consumption of diets known to be rich in antioxidant compounds (e.g., Mediterranean and high-fish diet), has shown to reduce ASCVD over decades. Future studies are needed to fill the gap between the data and targets derived from studies in animals and their pathogenetic and therapeutic significance in human ASCVD.

Oxidative stress, aging, antioxidant supplementation and their impact on human health: An overview

Aging is characterized by a progressive loss of tissue and organ function due to genetic and environmental factors, nutrition, and lifestyle. Oxidative stress is one the most important mechanisms of cellular senescence and increased frailty, resulting in several age-linked, noncommunicable diseases. Contributing events include genomic instability, telomere shortening, epigenetic mechanisms, reduced proteome homeostasis, altered stem-cell function, defective intercellular communication, progressive deregulation of nutrient sensing, mitochondrial dysfunction, and metabolic unbalance. These complex events and their interplay can be modulated by dietary habits and the ageing process, acting as potential measures of primary and secondary prevention. Promising nutritional approaches include the Mediterranean diet, the intake of dietary antioxidants, and the restriction of caloric intake. A comprehensive understanding of the ageing processes should promote new biomarkers of risk or diagnosis, but also beneficial treatments oriented to increase lifespan.

Changes in Carbon Partitioning and Pattern of Antioxidant Enzyme Activity Induced by Arginine Treatment in the Green Microalga Dunaliella salina Under Long-Term Salinity

In this work, the effects of arginine (Arg) on biochemical responses and antioxidant enzyme activity in the green microalga Dunaliella salina grown at different salt concentrations were investigated. Suspensions adapted with the concentrations of 1, 2, and 3 M NaCl were treated at the exponential growth phase with a concentration of 5 mM Arg. Salt stress was associated with a large decrease in the number of cells and non-reducing sugar levels but accumulated higher amounts of chlorophyll, β-carotene, reducing sugar, starch, total protein, free amino acid, and glycerol. Increased levels of protein carbonylation, lipid peroxidation, proteolysis, hydrogen peroxide, and antioxidant enzyme activity also occurred during salinity. Arg treatment changed the pattern of biochemical responses in the cells grown at high salinity by directing carbon flow to the biosynthesis of non-reducing sugars instead of starch, lowering levels of hydrogen peroxide, and downregulating antioxidant enzyme activity, but the levels of lipid peroxidation, glycerol, and β-carotene remained nearly unchanged. These results suggest that Arg treatment alleviates salinity-induced oxidative stress in D. salina cells by modifying carbon partitioning and inducing signaling molecules rather than antioxidant enzymes.

A Study on the Anti-NF-кB, Anti-Candida, and Antioxidant Activities of Two Natural Plant Hormones: Gibberellin A4 and A7

Introduction: Gibberellins (GA) are terpenoids that serve as important plant hormones by acting as growth and response modulators against injuries and parasitism. In this study, we investigated the in vitro anti-NF-κB, anti-Candida, and antioxidant activity of gibberellin A4 (GA4) and A7 (GA7) compounds, and further determined their toxicity in vivo. Methods: GA4 and GA7 in vitro toxicity was determined by MTT method, and nontoxic concentrations were then tested to evaluate the GA4 and GA7 anti-NF-κB activity in LPS-activated RAW-luc macrophage cell culture (luminescence assay). GA4 in silico anti-NF-κB activity was evaluated by molecular docking with the software “AutoDock Vina”, “MGLTools”, “Pymol”, and “LigPlot+”, based on data obtained from “The Uniprot database”, “Protein Data Bank”, and “PubChem database”. The GA4 and GA7 in vitro anti-Candida effects against Candida albicans (MYA 2876) were determined (MIC and MFC). GA7 was also evaluated regarding the viability of C. albicans preformed biofilm (microplate assay). In vitro antioxidant activity of GA4 and GA7 was evaluated against peroxyl radicals, superoxide anions, hypochlorous acid, and reactive nitrogen species. GA4 and GA7 in vivo toxicity was determined on the invertebrate Galleria mellonella larvae model. Results: Our data show that GA4 at 30 µM is nontoxic and capable of reducing 32% of the NF-κB activation on RAW-luc macrophages in vitro. In vitro results were confirmed via molecular docking assay (in silico), since GA4 presented binding affinity to NF-κB p65 and p50 subunits. GA7 did not present anti-NF-κB effects, but exhibited anti-Candida activity with low MIC (94 mM) and MFC (188 mM) values. GA7 also presented antibiofilm properties at 940 mM concentration. GA4 did not present anti-Candida effects. Moreover, GA4 and GA7 showed antioxidant activity against peroxyl radicals, but did not show scavenging activity against the other tested radicals. Both compounds did not affect the survival of G. mellonella larvae, even at extremely high doses (10 g/Kg). Conclusion: Our study provides preclinical evidence indicating that GA4 and GA7 have a favorable low toxicity profile. The study also points to GA4 and GA7 interference with the NF-κB via, anti-Candida activity, and a peroxyl radical scavenger, which we argue are relevant biological effects.

Efficacy of EPA-registered disinfectants against two human norovirus surrogates and Clostridioides difficile endospores

AIMS

To determine the efficacy of a panel of nine EPA-registered disinfectants against two human norovirus (HuNoV) surrogates (feline calicivirus [FCV] and Tulane virus [TuV]) and Clostridioides difficile endospores.

METHODS AND RESULTS

Nine EPA-registered products, five of which contained H2 O2 as active ingredient, were tested against infectious FCV, TuV and C. difficile endospores using two ASTM methods, a suspension and carrier test. Efficacy claims against FCV were confirmed for 8 of 9 products. The most efficacious product containing H2 O2 as ingredient achieved a >5.1 log reduction of FCV and >3.1 log reduction of TuV after 5 min, and >6.0 log reduction of C. difficile endospores after 10 min. Of the five products containing H2 O2 , no strong correlation (R2  = 0.25, p = 0.03) was observed between disinfection efficacy and H2 O2 concentration. Addition of 0.025% ferrous sulphate to 1% H2 O2 solution improved efficacy against FCV, TuV and C. difficile.

CONCLUSION

Disinfectants containing H2 O2 are the most efficacious disinfection products against FCV, TuV and C. difficile endospores. Product formulation, rather than the concentration of H2 O2 in a product, impacts the efficacy of a disinfection product.

SIGNIFICANCE AND IMPACT OF STUDY

H2 O2 -based disinfectants are efficacious against surrogate viruses for HuNoV and C. difficile endospores.

A dual-responsive probe for the simultaneous monitoring of viscosity and peroxynitrite with different fluorescence signals in living cells

We developed a dual-responsive fluorescent probe MC-V-P for the simultaneous detection of ONOO^- and viscosity by different imaging channels. MC-V-P has high sensitivity and selectivity, and shows good stability at different pH levels. Notably, the probe has two independent fluorescence signals toward ONOO^- and viscosity changes at 580 nm and 740 nm, respectively. Cell imaging experiment results demonstrated that MC-V-P exhibits low cytotoxicity and could be used to monitor viscosity and ONOO^- in living HepG2 cells simultaneously.

Is there a relationship between dynamic thiol/disulfide homeostasis and osteoarthritis progression?

We aim to determine serum dynamic thiol/disulphide homeostasis with novel methods in early-stage osteoarthritis and late-stage osteoarthritis patients and investigated whether it was associated with the progression of osteoarthritis risk or not. One hundred eighteen patients were included in this prospective study. Osteoarthritis patients were divided into five stages, according to the Kellgren-Lawrence scale. Dynamic thiol/disulphide homeostasis was determined with a novel spectrophotometric method. Late-stage osteoarthritis patients had significantly lower levels of native and total thiol than the patients of early-stage osteoarthritis. Disulphide, index-1, index-2 levels, and WOMAC score of late-stage osteoarthritis patients were significantly higher than the ones belonging to patients of early-stage osteoarthritis. Decreased native thiol and total thiol levels and increased WOMAC score and disulphide levels were independently associated with increased risk of late-stage osteoarthritis. We suggest that both WOMAC score and dynamic thiol/disulphide homeostasis may be implicated in the pathogenesis and progression of osteoarthritis. We also recommend that dynamic thiol/disulphide homeostasis may have clinical utility as possible markers of differential diagnosis of early-stage and late-stage osteoarthritis.

NUTRARET: Effect of 2-Year Nutraceutical Supplementation on Redox Status and Visual Function of Patients With Retinitis Pigmentosa: A Randomized, Double-Blind, Placebo-Controlled Trial

Oxidative stress plays a major role in the pathogenesis of retinitis pigmentosa (RP). The main goal of this study was to evaluate the effect of 2-year nutritional intervention with antioxidant nutraceuticals on the visual function of RP patients. Secondly, we assessed how nutritional intervention affected ocular and systemic redox status. We carried out a randomized, double-blind, placebo-controlled study. Thirty-one patients with RP participated in the study. RP patients randomly received either a mixture of nutraceuticals (NUT) containing folic acid, vitamin B6, vitamin A, zinc, copper, selenium, lutein, and zeaxanthin or placebo daily for 2 years. At baseline and after 2-year of the nutritional supplementation, visual function, dietetic-nutritional evaluations, serum concentration of nutraceuticals, plasma and aqueous humor concentration of several markers of redox status and inflammation were assessed. Retinal function and structure were assessed by multifocal electroretinogram (mfERG), spectral domain-optical coherence tomography (SD-OCT) and automated visual field (VF) tests. Nutritional status was estimated with validated questionnaires. Total antioxidant capacity, extracellular superoxide dismutase (SOD3), catalase (CAT), and glutathione peroxidase (GPx) activities, protein carbonyl adducts (CAR) content, thiobarbituric acid reactive substances (TBARS) formation (as indicator of lipid peroxidation), metabolites of the nitric oxide (NOX) and cytokine (interleukin 6 and tumor necrosis factor alpha) concentrations were assessed by biochemical and immunological techniques in aqueous humor or/and blood. Bayesian approach was performed to determine the probability of an effect. Region of practical equivalence (ROPE) was used. At baseline, Bayesian analysis revealed a high probability of an altered ocular redox status and to a lesser extent systemic redox status in RP patients compared to controls. Twenty-five patients (10 in the treated arm and 15 in the placebo arm) completed the nutritional intervention. After 2 years of supplementation, patients who received NUT presented better retinal responses (mfERG responses) compared to patients who received placebo. Besides, patients who received NUT showed better ocular antioxidant response (SOD3 activity) and lower oxidative damage (CAR) than those who received placebo. This study suggested that long-term NUT supplementation could slow down visual impairment and ameliorate ocular oxidative stress.

Capsaicin has potent anti-oxidative effects in vivo through a mechanism which is non-receptor mediated

Capsaicin (8-methyl-N-vanillyl-trans-6-nonenamide) is the active ingredient of chilli peppers and is responsible for the characteristic pungency. The ubiquitous human consumption of chilli peppers indicates their influence on human health. The effect of capsaicin through sensory neurons via TRPV1 activation has been well studied, but its non-neuronal effects are still not extensively explored. The purpose of this study was to investigate the in vivo antioxidant effect of capsaicin on erythrocytes of male Wistar rats. Markers of oxidative stress in blood were determined by assessing the plasma total antioxidant potential, activity of plasma membrane redox system, intracellular glutathione (GSH) level, ROS level, protein oxidation and lipid peroxidation. Results of this study suggest a significant protective effect of capsaicin against oxidative stress by enhancing FRAP, GSH level, PMRS activity and ameliorating ROS, MDA, PCO and AOPP.

Human γS-Crystallin Resists Unfolding Despite Extensive Chemical Modification from Exposure to Ionizing Radiation

Ionizing radiation has dramatic effects on living organisms, causing damage to proteins, DNA, and other cellular components. γ radiation produces reactive oxygen species (ROS) that damage biological macromolecules. Protein modification due to interactions with hydroxyl radical is one of the most common deleterious effects of radiation. The human eye lens is particularly vulnerable to the effects of ionizing radiation, as it is metabolically inactive and its proteins are not recycled after early development. Therefore, radiation damage accumulates and eventually can lead to cataract formation. Here we explore the impact of γ radiation on a long-lived structural protein. We exposed the human eye lens protein γS-crystallin (HγS) to high doses of γ radiation and investigated the chemical and structural effects. HγS accumulated many post-translational modifications (PTMs), appearing to gain significant oxidative damage. Biochemical assays suggested that cysteines were affected, with the concentration of free thiol reduced with increasing γ radiation exposure. SDS-PAGE analysis showed that irradiated samples form protein-protein cross-links, including nondisulfide covalent bonds. Tandem mass spectrometry on proteolytic digests of irradiated samples revealed that lysine, methionine, tryptophan, leucine, and cysteine were oxidized. Despite these chemical modifications, HγS remained folded past 10.8 kGy of γ irradiation as evidenced by circular dichroism and intrinsic tryptophan fluorescence spectroscopy.

Effects of the Incorporation of Calcium Chloride on the Physical and Oxidative Stability of Filled Hydrogel Particles

In this study, the effects of calcium chloride (CaCl2) addition on the physical and oxidative stabilities of filled hydrogel were investigated. The results revealed that CaCl2 significantly enhanced the particle size, interfacial layer thickness, apparent viscosity, and viscoelastic behavior of filled hydrogels and decreased their light and whiteness values (p < 0.05). This phenomenon was mainly attributed to the strong binding ability between Ca2+ and protein/pectin mixtures, which were present in the interfacial area or aqueous phase, as verified by cryo-scanning electron microscopy results. Moreover, lower levels of CaCl2 (2 or 4 mM) significantly enhanced the oxidative stability of filled hydrogels (p < 0.05), particularly at a concentration of 4 mM. However, a higher level of CaCl2 (6 or 8 mM) resulted in an electrostatic shielding effect, which resulted in the aggregation of multiple droplets and the flocculation of the filled hydrogels, which negatively affected the oxidative stability of filled hydrogels. The findings of this study indicated that appropriate Ca2+ levels (4 mM) improved the physical and oxidative stability of filled hydrogel, and this finding may provide useful insights for the development of effective delivery systems for specific applications.

Photo-activated proflavine degrades protein and impairs enzyme activity: Involvement of hydroxyl radicals

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Generation of hydroxyl radical (·OH) increased by proflavine upon illumination with fluorescent light.

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Proflavine resulted in oxidative modifications and degradation of protein and enzyme structure.

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The addition of Cu (II) augmented photo-illuminated proflavine to generate hydroxyl radicals.

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Proflavine-induced hydroxyl radicals have a deleterious influence on protein and enzyme activity.

Proflavine is a well-known antiseptic and bacteriostatic drug, however, it has the potential to be hazardous and mutagenic. Proflavine enters cells and intercalates between DNA base pairs, resulting in mutation and replication inhibition. Previously several investigators demonstrated that photo-activated proflavine generated double-stranded DNA breakage and protein structural alterations. The present study investigated the role of hydroxyl radical (·OH) due to activation of proflavine in the breakdown of protein and enzyme by photo-activated proflavine. The results show that the formation of hydroxyl radicals increased as the photo-illumination period increased, as did the concentrations of proflavine and Cu (II). As demonstrated by SDS-PAGE, the excess of free radicals due to proflavine resulted in oxidative modifications and degradation of BSA protein and trypsin enzyme. Additionally, with an increase in Cu (II) concentration, photo-illuminated proflavine induced a considerable loss of enzyme activity and also accelerated the degradation of the enzyme. Bathocuproine, a particular Cu (I)-sequestering agent, prevented protein degradation and enzyme inactivation. Hydroxyl radical scavengers inhibited the protein-damaging process, indicating that hydroxyl radicals play a substantial role in protein damage. The tryptophan moiety was quenched by proflavine, demonstrating that it binds to proteins and enzymes, changing their structure and activity. As a result, this study helps to better understand proflavine's deleterious influence on protein and enzyme degradation by oxygen-free radicals.

Use of metabolomics in refining the effect of an organic food intervention on biomarkers of exposure to pesticides and biomarkers of oxidative damage in primary school children in Cyprus: A cluster-randomized cross-over trial

BACKGROUND

Exposure to pesticides has been associated with oxidative stress in animals and humans. Previously, we showed that an organic food intervention reduced pesticide exposure and oxidative damage (OD) biomarkers over time; however associated metabolic changes are not fully understood yet.

OBJECTIVES

We assessed perturbations of the urine metabolome in response to an organic food intervention for children and its association with pesticides biomarkers [3-phenoxybenzoic acid (3-PBA) and 6-chloronicotinic acid (6-CN)]. We also evaluated the molecular signatures of metabolites associated with biomarkers of OD (8-iso-PGF2a and 8-OHdG) and related biological pathways.

METHODS

We used data from the ORGANIKO LIFE + trial (NCT02998203), a cluster-randomized cross-over trial conducted among primary school children in Cyprus. Participants (n = 149) were asked to follow an organic food intervention for 40 days and their usual food habits for another 40 days, providing up to six first morning urine samples (>850 samples in total). Untargeted GC-MS metabolomics analysis was performed. Metabolites with RSD ≤ 20% and D-ratio ≤ 50% were retained for analysis. Associations were examined using mixed-effect regression models and corrected for false-discovery rate of 0.05. Pathway analysis followed.

RESULTS

Following strict quality checks, 156 features remained out of a total of 610. D-glucose was associated with the organic food intervention (β = -0.23, 95% CI: -0.37,-0.10), aminomalonic acid showed a time-dependent increase during the intervention period (β_int = 0.012; 95% CI:0.002, 0.022) and was associated with the two OD biomarkers (β = -0.27, 95% CI:-0.34,-0.20 for 8-iso-PGF2a and β = 0.19, 95% CI:0.11,0.28 for 8-OHdG) and uric acid with 8-OHdG (β = 0.19, 95% CI:0.11,0.26). Metabolites were involved in pathways such as the starch and sucrose metabolism and pentose and glucuronate interconversions.

DISCUSSION

This is the first metabolomics study providing evidence of differential expression of metabolites by an organic food intervention, corroborating the reduction in biomarkers of OD. Further mechanistic evidence is warranted to better understand the biological plausibility of an organic food treatment on children's health outcomes.

Evaluation of the reactive oxygen metabolite levels in plasma, gingival crevicular fluid, and saliva in generalized chronic periodontitis patients before and after nonsurgical periodontal therapy: A case-control and interventional study

Background

Reactive oxygen metabolites (ROMs) produced in periodontitis could contribute to excessive tissue damage. Thus, treatment of chronic periodontitis may decrease the ROM levels. The aim of this study is to evaluate the ROM levels in plasma, saliva, and gingival crevicular fluid (GCF) in generalized chronic periodontitis (GCP) patients before and after nonsurgical periodontal treatment.

Materials and Methods

Two groups were included in this study. Group I consisted of 30 healthy controls (C) and Group II consisted of 30 subjects with GCP. Plaque index (PI), papillary bleeding index, Probing Depth (PD), and clinical attachment level were recorded. GCF, saliva, and plasma samples were collected from both groups. ROM levels were assessed. A baseline comparison was made between the two groups. Nonsurgical periodontal treatment was carried out for Group II subjects. Two months posttreatment, the clinical parameters and ROM levels in GCF, saliva, and plasma were reassessed in Group II, and the data were compared with their baseline values. Statistical analysis was done using SPSS 20 software and results were derived.

Results

Two months posttreatment, Group II exhibited significant reduction in ROM levels in plasma, saliva, and GCF with significant decrease in PI, bleeding on probing, probing depth, and attachment loss.

Conclusion

Thus, significant oxidative stress may occur in chronic periodontitis and nonsurgical periodontal therapy may be regarded as an effective treatment modality to treat the diseased periodontium, thereby preventing possible systemic diseases in future.