Increase In Peroxidation Levels Research Articles

The phytoremediator capacity of Quercus cerris L. against heavy metals contamination in the Ezer forest, Lebanon

Abstract The uncontrolled rise in heavy metal pollution due to anthropogenic activities has become a global environmental concern. Lebanon's Ezer forest, dominated by Quercus cerris L., is exposed to vehicular activity along its northern edge due to an unpaved public road and intensive recreational activities in its center. This study aimed to determine the concentrations of metals in Q. cerris leaves and soil across three distinct forest stands: S1 and S2 (polluted sites) and Ctrl (control site). Cadmium, chromium, lead, and aluminium were extracted via the wet digestion method and analyzed by Atomic Absorption Spectrometry. Additionally, hydrogen peroxide levels, the total carbohydrate and phenolic content in Q. cerris leaves, as well as the activity of antioxidant enzymes, were measured. The results revealed that Ezer forest is at risk of heavy metal contamination, with a significant increase in hydrogen peroxide levels at the polluted sites compared to the Ctrl site. The total carbohydrate and phenolic content was notably reduced at the polluted sites, while peroxidase and catalase activity increased, indicating that Q. cerris has developed adaptive mechanisms to cope with oxidative stress. National strategies to raise public awareness and reduce heavy metal contamination in the forest are urgently needed to protect the rare Q. cerris species.

Rapid changes in stress-related gene expression after short exposure of Arabidopsis leaves to cold plasma

Cold Atmospheric Plasma (CAP) technology has emerged as a promising tool in various biological applications due to its ability to generate a composite signal comprising reactive oxygen and nitrogen species, ultraviolet radiation, and electromagnetic fields, all while maintaining a stable temperature. Although CAP treatments have demonstrated significant effects on seed germination and plant growth, the direct molecular responses of plants to CAP exposure remain poorly understood. In this study, young Arabidopsis thaliana leaves were exposed to a brief 5- or 30-s localized CAP treatment, resulting in rapid and localized tissue damage without causing lethal effects on the entire plant. Molecular analyses conducted on the entire plant rosette revealed a notable increase in hydrogen peroxide levels, along with the upregulation of stress-related genes, akin to a wound response. Of particular interest, the activation of RelA/SpoT Homolog (RSH) genes encoding proteins that regulate the synthesis of the stress marker (p)ppGpp, also known as alarmone, and playing a major role in the energic regulation of photosynthesis, occurred shortly after CAP exposure. The expression of RSH genes was up-regulated after 5s CAP exposure, while the wound stress marker ZAT12 remained unaffected, highlighting a specific signalling pathway to activate RSH genes. This finding suggests the potential involvement of the alarmone signalling pathway in the plant's response to CAP exposure, thereby opening avenues for further exploration of metabolic pathways and signalling cascades induced by CAP treatment.

Investigation into the effect of acute exposure to chlorogenic acid in male wistar mice

Chlorogenic acid (CGA) is a natural polyphenolic compound widely present in various fruits, vegetables, and plant-based foods. It has gained considerable attention due to its potential health benefits including antioxidant, hepatoprotective, antibacterial, anti-inflammatory, anti-obesity, cardioprotective, neuroprotective, central nervous system stimulator, and anti-hypertensive amongst others. There is a dearth of information about acute exposure to chlorogenic acid which is also used as a food supplement. Ninety-six male Wistar mice were weight-matched into 8 groups (n=12). Group 1 was treated with distilled water, Group 2 received 1% ethanol, while Groups 3-8 were treated with 30, 60, 120, 240, 480 and 1,000 mg/kg body weight doses of CGA, respectively. Six animals were bled and sacrificed per group 24 hours post-treatment, and the liver and kidney were excised. Sections of the organs were fixed in 10% formalin for histopathological examination. Various antioxidant parameters were assayed in the liver and kidney samples using standard methods. A liver function test was also carried out on the liver samples. Haematological analysis was carried out as well as histopathology analysis of the liver and kidney samples. The remainder of the treated mice in each group were observed for mortality 24 hours post-treatment and for two weeks. Statistical analysis was performed using one-way analysis of variance (ANOVA) with p-values less than 0.05 considered to be significant. The results of this study show that chlorogenic acid led to dose-dependent increased levels of hydrogen peroxide and albumin, increased activity of alkaline phosphatase with decreased activities and levels of alanine aminotransferase, aspartate aminotransferase and bilirubin in the liver function while there were increased hydrogen peroxide levels in the kidney. The haematological parameters were not affected and the histopathological examination complemented the results with mild to moderate lesions in the liver and none in the kidney. Although, the lethal dose (LD 50-i.e., the dose at 50% mortality) was not established in this study. Therefore, chlorogenic acid should be ingested with caution.

Eccentric contraction increases hydrogen peroxide levels and alters gene expression through Nox2 in skeletal muscle of male mice.

Hydrogen peroxide (H2O2) is one of the key signaling factors regulating skeletal muscle adaptation to muscle contractions. Eccentric (ECC) and concentric (CONC) contractions drive different muscle adaptations with ECC resulting in greater changes. The present investigation tested the hypothesis that ECC produces higher cytosolic and mitochondrial H2O2 concentrations [H2O2] and alters gene expression more than CONC. Cytosolic and mitochondrial H2O2-sensitive fluorescent proteins, HyPer7 and MLS-HyPer7, were expressed in the anterior tibialis muscle of C57BL6J male mice. Before and for 60 min after either CONC or ECC (100 Hz, 50 contractions), [H2O2]cyto and [H2O2]mito were measured by in vivo fluorescence microscopy. RNA sequencing was performed in control (noncontracted), CONC, and ECC muscles to identify genes impacted by the contractions. [H2O2]cyto immediately after ECC was greater than after CONC (CONC: +6%, ECC: +11% vs. rest, P < 0.05) and remained higher for at least 60 min into recovery. In contrast, the elevation of [H2O2]mito was independent of the contraction modes (time; P < 0.0042, contraction mode; P = 0.4965). The impact of ECC on [H2O2]cyto was abolished by NADPH oxidase 2 (Nox2) inhibition (GSK2795039). Differentially expressed genes were not present after CONC or ECC + GSK but were found after ECC and were enriched for vascular development and apoptosis-related genes, among others. In conclusion, in mouse anterior tibialis, ECC, but not CONC, evokes a pronounced cytosolic H2O2 response, caused by Nox2, that is mechanistically linked to gene expression modifications.NEW & NOTEWORTHY This in vivo model successfully characterized the effects of eccentric (ECC) and concentric (CONC) contractions on cytosolic and mitochondrial [H2O2] in mouse skeletal muscle. Compared with CONC, ECC induced higher and more sustained [H2O2]cyto-an effect that was abolished by Nox2 inhibition. ECC-induced [H2O2]cyto elevations were requisite for altered gene expression.

Precise partial root-zone irrigation technique and potassium-zinc fertigation management improve maize physio-biochemical responses, yield, and water use in arid climate

BackgroundTo optimize irrigation water use and productivity, understanding the interactions between plants, irrigation techniques, and fertilization practices is crucial. Therefore, the experiment aims to assess the effectiveness of two application methods of potassium humate combined with chelated zinc under partial root-zone drip irrigation techniques on maize nutrient uptake, yield, and irrigation water use efficiency across two irrigation levels.MethodsOpen-field experiments were carried out in two summer seasons of 2021 and 2022 under alternate and fixed partial root-zone drip irrigation techniques to investigate their impacts at two irrigation levels and applied foliar and soil applications of potassium humate or chelated zinc in a sole and combinations on maize.ResultsDeficit irrigation significantly increased hydrogen peroxide levels and decreased proline, antioxidant enzymes, carbohydrate, chlorophyll (a + b), and nutrient uptake in both partial root-zone techniques. The implementation of combined soil application of potassium humate and chelated zinc under drought conditions on maize led to varying impacts on antioxidant enzymes and nutritional status, depending on the type of partial root-zone technique. Meanwhile, the results showed that fixed partial root-zone irrigation diminished the negative effects of drought stress by enhancing phosphorus uptake (53.8%), potassium uptake (59.2%), proline (74.4%) and catalase (75%); compared to the control. These enhancements may contribute to improving the defense system of maize plants in such conditions. On the other hand, the same previous treatments under alternate partial root zone modified the defense mechanism of plants and improved the contents of peroxidase, superoxide dismutase, and the uptake of magnesium, zinc, and iron by 81.3%, 82.3%, 85.1%, 56.9%, and 80.2%, respectively.ConclusionsAdopting 75% of the irrigation requirements and treating maize plants with the soil application of 3 g l−1 potassium humate combined with 1.25 kg ha−1 chelated zinc under alternate partial root-zone technique, resulted in the maximum root length, leaf water content, chlorophyll content, yield, and irrigation water use efficiency.

Interplay of miRNAs and molecular pathways in spaceflight-induced depression: Insights from a rat model using simulated complex space environment.

Depression is a significant concern among astronauts, yet the molecular mechanisms underlying spaceflight-induced depression remain poorly understood. MicroRNAs (miRNAs) have emerged as potential regulators of neuropsychiatric disorders, including depression, but their specific role in space-induced depression remains unexplored. This study aimed to elucidate the involvement of candidate miRNAs (miR-455-3p, miR-206-3p, miR-132-3p, miR-16-5p, miR-124-3p, and miR-145-3p) and their interaction with differentially expressed genes (DEGs) in the neurobiology of spaceflight-induced depressive behavior. Using a simulated space environmental model (SCSE) for 21 days, depressive behavior was induced in rats, and candidate miRNA expressions and DEGs in the cortex region were analyzed through qRT-PCR and HPLC, respectively. Results showed that SCSE-exposed rats exhibited depressive behaviors, including anhedonia, increased immobility, and anxiousness compared to controls. Further analysis revealed increased hydrogen peroxide levels and decreased superoxide dismutase levels in the SCSE group, indicating abnormal oxidative stress in the cerebral cortex. Moreover, miRNA analysis demonstrated significant upregulation of miR-455-3p, miR-206-3p, miR-132-3p, and miR-16-5p expression. Among the DEGs identified, the in silico analysis highlighted their involvement in crucial pathways such as glutamatergic signaling, GABA synaptic pathway, and calcium signaling, implicating their role in spaceflight-induced depression. Protein-protein interaction analysis identified hub genes, including DLG4, DLG3, GRIN1, GRIN2B, GRIN2A, SYNGAP1, DLGAP1, GRIK2, and GRIN3A, impacting neuronal dysfunction functions in the cortex region of SCSE depressive rats. DLG4 emerged as a core gene regulated by miR-455-3p and miR-206-3p. Overall, this study underscores the potential of miRNAs as biomarkers for mood disorders and neurological abnormalities associated with spaceflight, advancing health sciences, and space health care.

Polyols induce acute oxidative stress and mortality in Indian malaria vector Anopheles stephensi (Diptera: Culicidae): potential for use as sugar-cum-toxin source in toxic sugar baits.

Development of insecticide resistance in the major malaria vectors has necessitated the development of novel vector control tools. One such strategy involves the use of toxic sugar baits that targets the sugar-feeding behaviour of mosquito vectors. In this study, we investigated the potential of polyols, as a toxic food (sugar) source in toxic sugar baits against the malaria vector Anopheles stephensi Liston. We examined the acute toxicity of six polyols, namely, erythritol, glycerol, mannitol, propylene glycol (PG), sorbitol, and xylitol on adult female An. stephensi mosquitoes at two different concentrations - 2% and 10%. We also studied changes in fecundity, egg hatchability and mid-gut peroxide levels induced by polyol exposure. Among the six polyol compounds tested, PG was most toxic and lethal followed by glycerol and erythritol (P < 0.001) compared to the control (sucrose). PG induced acute mortality at different tested concentrations. In the erythritol- and glycerol-fed groups, a dose-dependent effect on mortality was observed. Glycerol evidently reduced fecundity and egg-hatchability in gonotrophic cycles G1 and G2. Sucrose was the preferred food source (48%), followed by erythritol (18%), PG (10%) and glycerol (8%). Ingestion of polyols increased peroxide levels in mosquito guts, which persisted for extended durations ultimately resulting in rapid mortality (P < 0.05). The present study highlights the usefulness of sugar polyols for the development of toxic sugar baits with minimal yet effective ingredients. Further research could be focused on field experiments and on the exploration of synergistic effects of different polyols for optimization of field applications. © 2024 Society of Chemical Industry.

2-iodohexadecanal induces autophagy during goiter involution

BackgroundIodine plays an important role in thyroid physiology and biochemistry. The thyroid is capable of producing different iodolipids such as 2-iodohexadecanal (2-IHDA). Data from different laboratories have shown that 2-IHDA inhibits several thyroid parameters and it has been postulated as intermediary on the action of iodide function. ObjectiveTo explore different mechanisms involved during the involution of the hyperplastic thyroid gland of Wistar rats towards normality induced by 2-IHDA. Methods: Goiter was induced by the administration of MMI for 10 days, then the treatment was discontinued and Wistar rats were injected with 2-IHDA or KI. ResultsDuring involution, 2-IHDA treatment reduced PCNA expression compared to spontaneous involution. KI treatment caused an increase of Caspase-3 activity and TUNEL-positive cells. In contrast, 2-IHDA failed to alter this value but induced an increase of LC3B expression. KI but not 2-IHDA led to an increase in peroxides levels, catalase and glutathione peroxidase activity. ConclusionsWe demonstrated that 2-IHDA, in contrast to iodide, did not lead to an increase in oxidative stress or apoptosis induction, indicating that the involution triggered by 2-IHDA in Wistar rats, is primarily due to the inhibition of cell proliferation and the induction of autophagy.

Nitro-oxidative response to internalized multi-walled carbon nanotubes in Brassica napus and Solanum lycopersicum

In addition to their beneficial effects on plant physiology, multi-walled carbon nanotubes (MWCNTs) are harmful to plants in elevated concentrations. This study compared the effects of two doses of MWCNT (10 and 80 mg/L) in Brassica napus and Solanum lycopersicum seedlings focusing on nitro-oxidative processes. The presence of MWCNTs was detectable in the root and hypocotyl of both species. Additionally, transmission electron microscopy analysis revealed that MWCNTs are heavily transformed within the root cells forming large aggregates. The uptake of MWCNTs negatively affected root viability and root cell proliferation of both species, but more intense toxicity was observed in S. lycopersicum compared to B. napus. The presence of MWCNT triggered more intense protein carbonylation in the relative sensitive S. lycopersicum, where increased hydrogen peroxide levels were observed. Moreover, MWCNT exposure increased the level of physiological protein tyrosine nitration which was more intense in S. lycopersicum where notable peroxynitrite accumulation occurred. These suggest for the first time that MWCNT triggers secondary nitro-oxidative stress which contributes to its toxicity. Moreover, the results indicate that the extent of the nitro-oxidative processes is associated with the extent of MWCNT toxicity.

The primary neurotoxic factor, Lansamide I, from Clausena lansium fruits and metabolic dysfunction invoked

Wampee (Clausena lansium) is a common fruit in South Asia. The pulp is a tasty food, and the seed is a typical traditional herb in China. However, we identified a primary toxic compound, Lansamide I, by NMR and X-ray diffraction of single-crystal. The compound occurred at 4.17 ± 0.16 mg/kg of dried seed and 0.08 ± 0.01 g/kg of fresh fruit. In our phenotype-based toxicity investigation, the compound caused decreased hatchability of zebrafish eggs, increased malformations such as enlarged yolk sacs and pericardial edema, and delayed body length development. Moreover, the compound also caused nerve cell damage and decreased locomotor activity. The compound caused an increase in peroxidation levels in vivo, with increases in both malondialdehyde and superoxide dismutase levels, but did not interfere with acetylcholinesterase levels. Metabolomic studies found that the compound caused significant up-regulation of 16 metabolites, mainly amino acids and peptides, which were involved in the nucleotide metabolism pathway and the betaine biosynthesis module. The qRT-PCR revealed that the substance interfered with the mRNA expression of tat and dctpp. These discoveries offer fresh perspectives on the toxicity mechanisms and metabolic response to the primary harmful molecules in wampee, which could inform the rational usage of wampee resources.

Nickel chloride generates cytotoxic ROS that cause oxidative damage in human erythrocytes

BackgroundNickel is a heavy metal that is regarded as a possible hazard to living organisms due to its toxicity and carcinogenicity. Nickel chloride (NiCl2), an inorganic divalent Ni compound, has been shown to cause oxidative stress in cells by altering the redox equilibrium. We have investigated the effect of NiCl2 on isolated human erythrocytes under in vitro condition. MethodsIsolated erythrocytes were treated with different concentrations of NiCl2 (25–500 µM) for 24 h at 37 ºC. Hemolysates were prepared and several biochemical parameters were analyzed in them. ResultsTreatment of erythrocytes with NiCl2 enhanced the intracellular generation of reactive oxygen species (ROS). A significant increase in hydrogen peroxide levels and oxidation of proteins and lipids was also seen. This was accompanied by a reduction in levels of nitric oxide, glutathione, free amino groups and total sulfhydryl groups. NiCl2 treatment impaired both enzymatic and non-enzymatic defense systems, resulting in lowered antioxidant capacity and diminished ability of cells to quench free radicals and reduce metal ions. NiCl2 exposure also had an inhibitory effect on the activity of enzymes involved in pathways of glucose metabolism (glycolytic and pentose phosphate shunt pathways). Increased level of methemoglobin, which is inactive in oxygen transport, was also seen. The rate of heme breakdown increased resulting in the release of free iron. Exposure to NiCl2 led to considerable cell lysis, indicating damage to the erythrocyte membrane. This was supported by the inhibition of membrane bound enzymes and increase in the osmotic fragility of NiCl2 treated cells. NiCl2 treatment caused severe morphological alterations with the conversion of normal discocytes to echinocytes. All changes were seen in a NiCl2 concentration-dependent manner. ConclusionNiCl2 generates cytotoxic ROS in human erythrocytes which cause oxidative damage that can decrease the oxygen carrying capacity of blood and also lead to anemia.

Redox status of juvenile Nile tilapia, Oreochromis niloticus (Linnaeus, 1758), fed diets supplemented with poultry liver protein hydrolysate as feed aditive

Plant ingredients, when used as substitutes for animal protein ingredients, can negatively influence fish growth. Thus, feed additives have been used to enhance feed consumption, nutrient utilization efficiency and stress tolerance under intensive management conditions. One such potential feed additive in aquafeeds is poultry liver protein hydrolysate (PLPH), which is rich in essential amino acids and has in vitro antioxidant and antibacterial properties. In this study, we aimed to evaluate the effect of poultry liver protein hydrolysate as feed additive on the productive performance of Nile tilapia reared in a water recirculation system and investigate stress responses and redox status after an air exposure challenge. Nile tilapia juveniles were randomly distributed in 24 aquariums and fed plant-based diets supplemented with increasing levels of PLPH (0, 10, 20, and 40 g/kg) over a 45-day period. At the end of the experiment, we did not observe a significant effect of PLPH on productive performance variables or body indices (P > 0.05). Air exposure triggered stress responses in fish, as evidenced by an increase in blood glucose (P < 0.05). However, PLPH supplementation did not mitigate this effect (P > 0.05). Regarding redox status, a quadratic effect of PLPH supplementation was observed on malondialdehyde (P = 0.003) levels, as well as the activities of superoxide dismutase (P = 0.015), catalase (P = 0.015), and glutathione S-transferase (P = 0.001). Optimum PLPH supplementation levels were estimated at 25.14, 25.91, 22.57, and 18.83 g/kg, respectively, for these redox parameters. Increasing PLPH levels decreased carbonylated protein contents (P = 0.001) but increased hydrogen peroxide levels in the gills (P = 0.006). Although PLPH supplementation improved antioxidant enzyme activity, and attenuated protein damage, it concurrently increased reactive oxygen species production and lipid peroxidation. Further studies are necessary to elucidate the underlying mechanisms of action by which protein hydrolysates influence the redox status of fish reared under intensive management.

Constitutive knock-in of MnSODK68R causes dilated cardiomyopathy and senescence in mice

The mitochondrial superoxide dismutase (SOD2 or MnSOD) is an essential enzyme for managing oxidative stress, particularly by removing the highly reactive superoxide generated during the normal functioning of the electron transport chain. The activity of MnSOD is regulated post-translationally by acetylation, specifically at lysine 68. The deacetylated form of MnSOD is catalytically active, and it has been shown that the deacetylation mimic, MnSOD K68R in which lysine 68 has been replaced with arginine, has upregulated dismutase activity in MCF7 and T47D human breast cancer cells. Overexpression of MnSOD has been shown to increase lifespan and protect against oxidative stress in the aging heart. We investigated a MnSOD K68R knock-in mouse with ubiquitous expression of the mutant enzyme and expected similar effects as the MnSOD overexpressing mice. However, we have found that MnSOD K68R homozygous knock-in mice develop dilated cardiomyopathy and have significantly decreased ejection fraction as evidenced by echocardiography at a young age. These mice also exhibit lower blood pressure compared to wild-type mice. Strikingly, these mice exhibit higher body weight, with increased lean mass and food consumption. Mitochondria isolated from MnSOD K68R knock-in mouse hearts showed higher respiratory capacity than WT counterparts. Biochemical analysis revealed increased lipid peroxidation, oxidized peroxiredoxin and senescence markers, possibly indicative of a premature aging phenotype. We conclude that MnSOD constitutive function upregulation may produce a sustained increase in hydrogen peroxide levels that could cause senescence and lead to dilated cardiomyopathy. This research was funded by NCI grant R01CA152601 and, R01CA214025, and the Cancer Prevention and Research Institute of Texas grant number RR20012. JS is supported by T32 AG 021890. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

An aqueous olive leaf extract (OLE) ameliorates parameters of oxidative stress associated with lipid accumulation and induces lipophagy in human hepatic cells.

Fatty liver is a disease characterized by a buildup of lipids in the liver, often resulting from excessive consumption of high-fat-containing foods. Fatty liver can degenerate, over time, into more severe forms of liver diseases, especially when oxidative stress occurs. Olive leaf extract (OLE) is a reliable source of polyphenols with antioxidant and hypolipidemic properties that have been successfully used in medicine, cosmetics, and pharmaceutical products. Using "green" solvents with minimal impact on the environment and human health, which simultaneously preserves the extract's beneficial properties, represents one of the major challenges of biomedical research. In the present study, we assayed the potential antioxidant and lipid-lowering effect of a "green" OLE obtained by a water ultrasound-assisted extraction procedure, on the human hepatic HuH7 cell line, treated with a high concentration of free fatty acids (FFA). We found that high FFA concentration induced lipid accumulation and oxidative stress, as measured by increased hydrogen peroxide levels. Moreover, the activity of antioxidant enzymes, catalase, superoxide dismutase, and glutathione peroxidase, was reduced upon FFA treatment. Coincubation of high FFA with OLE reduced lipid and H2O2 accumulation and increased the activity of peroxide-detoxifying enzymes. OLE ameliorated mitochondrial membrane potential, and hepatic parameters by restoring the expression of enzymes involved in insulin signaling and lipid metabolism. Electron microscopy revealed an increased autophagosome formation in both FFA- and FFA + OLE-treated cells. The study of the autophagic pathway indicated OLE's probable role in activating lipophagy.

Identification of the Citrus Superoxide Dismutase Family and Their Roles in Response to Phytohormones and Citrus Bacterial Canker

Superoxide dismutases (SODs) play critical roles in plants, especially in the maintenance of redox homeostasis. The response of SODs in Citrus (Citrus sinensis (L.) Osbeck) to citrus bacterial canker (CBC) infection were investigated. The CsSODs were identified, and their gene structures, phylogeny, conserved domains and motifs, predicted interactions, and chromosomal distribution were analyzed. CsSOD expression in response to stress-related plant hormones (salicylic acid, SA; methyl jasmonate, MeJA; and abscisic acid, ABA) and Xanthomonas citri subsp. citri (Xcc) infection were also investigated. Thirteen CsSODs were identified in C. sinensis, including four Fe/MnSODs and nine Cu/ZnSODs with typical functional domains. The CsSODs were distributed on chromosomes 3, 5, 7, and 8. Specific hormone-response motifs were identified in the gene promoter regions. Ten genes were induced by MeJA treatment, as shown by qRT-PCR, and were upregulated in the CBC-susceptible Wanjincheng citrus variety, while CsSOD06 and CsSOD08 were upregulated by ABA in both the Wanjincheng and the CBC-resistant Kumquat varieties. Xcc infection significantly altered the levels of most CsSODs. The overexpression of CsSOD06 and CsSOD08 resulted in increased hydrogen peroxide levels and SOD activity. Our findings highlight the significance of SOD enzymes in the plant response to pathogen infection and have a potential application for breeding CBC-tolerant citrus varieties.

Exogenous seed treatment with proline and its consequences to Norway spruce (Picea abies (L.) H. Karst) seedling establishment

Accumulation of proline is a defense mechanism against external stress conditions, preventing damage to the structure and function of cells and improving plant development processes, such as germination. The purpose of this study was to investigate proline treatment as a means of improving the germination and development of Norway spruce seedlings. The effect of exogenous proline has been studied in three stages of initial plant development. The collected seeds were soaked in water or 8 mM proline solution and placed on the germinators. The germination capacity and the mean germination time were determined. Seedlings with radicles &gt;10 mm were transferred to the sand-peat substrate at a constant temperature of 20 °C. Seedlings at 3 subsequent developmental stages (S1 – germinated seeds with radicles &gt; 3 mm; S2 – seedlings with radicles &gt;10 mm; S3 – established seedlings grown for 90 days) were examined for the oxygen consumption rate, total antioxidant capacity, hydrogen peroxide level, malondialdehyde level and intracellular proline content. Proline treatment was conducive to lowering the levels of hydrogen peroxide and malondialdehyde at stage S1. At the subsequent stages of development, the levels of hydrogen peroxide and malondialdehyde increased, and at the S3 stage, there was also a marked increase in total antioxidant capacity. At stage S3, the seedlings of the proline treatment were characterized by a lower total mass, and the response to exogenous proline was stronger in the root tissues than in the leaves. The oxygen consumption rate was higher for the proline treatment at all stages of development. Seedlings at the analyzed stages of establishment differed in response to proline treatment. Exogenous proline had some beneficial effects during the first phase of germination by reducing the level of hydrogen peroxide and improving the condition of lipid membranes. In the subsequent stages of seedling development, in response to the same concentration of proline solution, undesirable effects, such as an increase in hydrogen peroxide levels and damage to cytoplasmic membranes, were observed. Optimal concentrations of exogenous proline should be determined prior to commercial use of proline treatment to improve plant stress tolerance.

The RelB-BLNK Axis Determines Cellular Response to a Novel Redox-Active Agent Betamethasone during Radiation Therapy in Prostate Cancer.

Aberrant levels of reactive oxygen species (ROS) are potential mechanisms that contribute to both cancer therapy efficacy and the side effects of cancer treatment. Upregulation of the non-canonical redox-sensitive NF-kB family member, RelB, confers radioresistance in prostate cancer (PCa). We screened FDA-approved compounds and identified betamethasone (BET) as a drug that increases hydrogen peroxide levels in vitro and protects non-PCa tissues/cells while also enhancing radiation killing of PCa tissues/cells, both in vitro and in vivo. Significantly, BET increases ROS levels and exerts different effects on RelB expression in normal cells and PCa cells. BET induces protein expression of RelB and RelB target genes, including the primary antioxidant enzyme, manganese superoxide dismutase (MnSOD), in normal cells, while it suppresses protein expression of RelB and MnSOD in LNCaP cells and PC3 cells. RNA sequencing analysis identifies B-cell linker protein (BLNK) as a novel RelB complementary partner that BET differentially regulates in normal cells and PCa cells. RelB and BLNK are upregulated and correlate with the aggressiveness of PCa in human samples. The RelB-BLNK axis translocates to the nuclear compartment to activate MnSOD protein expression. BET promotes the RelB-BLNK axis in normal cells but suppresses the RelB-BLNK axis in PCa cells. Targeted disruptions of RelB-BLNK expressions mitigate the radioprotective effect of BET on normal cells and the radiosensitizing effect of BET on PCa cells. Our study identified a novel RelB complementary partner and reveals a complex redox-mediated mechanism showing that the RelB-BLNK axis, at least in part, triggers differential responses to the redox-active agent BET by stimulating adaptive responses in normal cells but pushing PCa cells into oxidative stress overload.

No-ozone cold plasma can kill oral pathogenic microbes in H2O2-dependent and independent manner

To apply the sterilisation effect of low-temperature plasma to the oral cavity, the issue of ozone from plasma must be addressed. In this study, a new technology for generating cold plasma with almost no ozone is developed and is named Nozone (no-ozone) Cold Plasma (NCP) technology. The antimicrobial efficacy of the NCP against four oral pathogens is tested, and its specific mechanism is elucidated. The treatment of NCP on oral pathogenic microbes on a solid medium generated a growth inhibition zone. When NCP is applied to oral pathogens in a liquid medium, the growth of microbes decreased by more than 105 colony forming units, and the bactericidal effect of NCP remained after the installation of dental tips. The bactericidal effect of NCP in the liquid medium is due to the increase in hydrogen peroxide levels in the medium. However, the bactericidal effect of NCP in the solid medium depends on the charged elements of the NCP. Furthermore, the surface bactericidal efficiency of the dental-tip-installed NCP is proportional to the pore size of the tips and inversely proportional to the length of the tips. Overall, we expect this NCP device to be widely used in dentistry in the near future.

SARS-CoV-2 induces mitochondrial dysfunction and cell death by oxidative stress/inflammation in leukocytes of COVID-19 patients

The inflammation and activation of the immune system induced by SARS-CoV-2 are mediated by a pro-oxidant microenvironment that can induce cytotoxic effects that enhance tissue damage, favoring organic deterioration. We investigated whether the induction of oxidative stress and inflammation by COVID-19 infection could inhibit mitochondrial function and cause cellular damage in leukocytes. We evaluated levels of oxidative/inflammation markers and their correlation with mitochondrial function and leukocyte cell death in COVID-19 patients at two moments: viremia and severe sepsis with multi-organ failure. COVID-19 induces increased oxidative stress and inflammation markers that activate cellular damage processes. In the viremia stage, an increase in peroxide, nitric oxide, carbonylated proteins, and IL-6 was observed, which was correlated with a marked inhibition of mitochondrial function, decreased cell viability, early apoptosis, necrosis, and leukocytes-reactivity. The severe sepsis stage with multi-organ failure also showed a further increase in levels of peroxide, carbonylated proteins, and IL-6, with a slight decrease in nitric oxide. This oxidative process and inflammation were correlated with less inhibition of mitochondrial function, decreased cell viability and an increase in late apoptosis, and morphology changes evidencing damage in the leukocytes. SARS-CoV-2 induced damage promotes levels of oxidative stress and inflammation markers and mitochondrial dysfunction that potentiate morphological changes and cell death in leukocytes. These processes explain the rapid changes in the immune system, and that present an initial over-activation and early massive death due to SARS-CoV-2 infection, promoting endothelial-alveolar damage that would cause multi-organ failure, sustained by oxidative stress and inflammation.

Cellular antioxidant mechanisms control immunoglobulin light chain-mediated proximal tubule injury

A major cause of morbidity and mortality in multiple myeloma is kidney injury from overproduction of monoclonal immunoglobulin light chains (FLC). FLC can induce damage through the production of hydrogen peroxide, which activates pro-inflammatory and pro-apoptotic pathways. The present study focused on catalase, a highly conserved antioxidant enzyme that degrades hydrogen peroxide. Initial findings were that FLC increased hydrogen peroxide levels but also decreased catalase levels and activity in proximal tubule epithelium. In order to clarify, we showed that the phosphatidylinositol 3-kinase inhibitor, LY294002, inhibited FLC-induced Akt-mediated deactivation of Forkhead box O class 3a (FoxO3a) and increased catalase activity in proximal tubule cells. Augmented catalase activity decreased FLC-mediated production of hydrogen peroxide as well as the associated increase in High Mobility Group Box 1 (HMGB1) protein release and caspase-3 activity. Coincubation of cells with FLC and an allosteric activator of Sirtuin 1 (SIRT1) was also sufficient to increase catalase activity and promote similar cytoprotective effects. Our studies confirmed that the mechanism of downregulation of catalase by FLC involved deactivation of FoxO3a and inhibition of SIRT1. Mechanistic understanding of catalase regulation allows for future treatments that target pathways that increase catalase in the setting of proximal tubule injury from FLC.