Levels Of Reactive Nitrogen Species Research Articles

Hematopoiesis Revolves Around the Primordial Evolutional Rhythm of Purinergic Signaling and Innate Immunity – A Journey to the Developmental Roots

A cell's most significant existential task is to survive by ensuring proper metabolism, avoiding harmful stimuli, and adapting to changing environments. It explains why early evolutionary primordial signals and pathways remained active and regulate cell and tissue integrity. This requires energy supply and a balanced redox state. To meet these requirements, the universal intracellular energy transporter purine nucleotide-adenosine triphosphate (ATP) became an important signaling molecule and precursor of purinergic signaling after being released into extracellular space. Similarly, ancient proteins involved in intracellular metabolism gave rise to the third protein component (C3) of the complement cascade (ComC), a soluble arm of innate immunity. These pathways induce cytosol reactive oxygen (ROS) and reactive nitrogen species (RNS) that regulate the redox state of the cells. While low levels of ROS and RNS promote cell growth and differentiation, supra-physiological concentrations can lead to cell damage by pyroptosis. This balance explains the impact of purinergic signaling and innate immunity on cell metabolism, organogenesis, and tissue development. Subsequently, along with evolution, new regulatory cues emerge in the form of growth factors, cytokines, chemokines, and bioactive lipids. However, their expression is still modulated by both primordial signaling pathways. This review will focus on the data that purinergic signaling and innate immunity carry on their ancient developmental task in hematopoiesis and specification of hematopoietic stem/progenitor cells (HSPCs). Moreover, recent evidence shows both these regulatory pathways operate in a paracrine manner and inside HSPCs at the autocrine level.Graphical

Hormetic action of cyanide: plant gasotransmitter and poison

AbstractHydrogen cyanide (HCN) occurs in living organisms and in the environment. This is a widely known poison but is also considered as a gasotransmitter. For most higher plants, microorganisms and animals HCN is toxic, especially at elevated concentrations. However, plants’ sensitivity to this compound is lower than animals’ due to the activity of an alternative oxidase in the mitochondrial respiration chain. All higher plants synthesize HCN as a co-product during the final step of ethylene biosynthesis, whilst some plant species release it from cyanogenic compounds, accumulated for diverse physiological purposes. This molecule is used as a toxic bomb against herbivores, as a source of nitrogen in N-deficient plants, or as a regulator of seed dormancy state. The toxicity of HCN is mainly due to the inhibition of the activity of several metalloenzymes: iron-containing enzymes, molybdoenzymes and enzymes that contain zinc or copper. HCN impacts cellular metabolism by modulation of the reactive oxygen species and reactive nitrogen species levels, and via modifications of proteins (S-cyanylation, oxidation). The aim of this work is to describe the dual (toxic and signalling) mode of cyanide action in plants at a cellular level.

FeTPPS, a Peroxynitrite Decomposition Catalyst, Ameliorates Nitrosative Stress in Human Spermatozoa.

Excessive levels of reactive nitrogen species (RNS), such as peroxynitrite, promote nitrosative stress, which is an important cause of impaired sperm function. The metalloporphyrin FeTPPS is highly effective in catalyzing the decomposition of peroxynitrite, reducing its toxic effects in vivo and in vitro. FeTPPS has significant therapeutic potential in peroxynitrite-related diseases; however, its effects on human spermatozoa under nitrosative stress have not been described. This work aimed to evaluate the in vitro effect of FeTPPS against peroxynitrite-mediated nitrosative stress in human spermatozoa. For this purpose, spermatozoa from normozoospermic donors were exposed to 3-morpholinosydnonimine, a molecule that generates peroxynitrite. First, the FeTPPS-mediated peroxynitrite decomposition catalysis was analyzed. Then, its individual effect on sperm quality parameters was evaluated. Finally, the effect of FeTPPS on ATP levels, motility, mitochondrial membrane potential, thiol oxidation, viability, and DNA fragmentation was analyzed in spermatozoa under nitrosative stress conditions. The results showed that FeTPPS effectively catalyzes the decomposition of peroxynitrite without affecting sperm viability at concentrations up to 50 μmol/L. Furthermore, FeTPPS mitigates the deleterious effects of nitrosative stress on all sperm parameters analyzed. These results highlight the therapeutic potential of FeTPPS in reducing the negative impact of nitrosative stress in semen samples with high RNS levels.

The Impact of Serum Levels of Reactive Oxygen and Nitrogen Species on the Disease Severity of COVID-19.

Elucidation of the redox pathways in severe coronavirus disease 2019 (COVID-19) might aid in the treatment and management of the disease. However, the roles of individual reactive oxygen species (ROS) and individual reactive nitrogen species (RNS) in COVID-19 severity have not been studied to date. The main objective of this research was to assess the levels of individual ROS and RNS in the sera of COVID-19 patients. The roles of individual ROS and RNS in COVID-19 severity and their usefulness as potential disease severity biomarkers were also clarified for the first time. The current case-control study enrolled 110 COVID-19-positive patients and 50 healthy controls of both genders. The serum levels of three individual RNS (nitric oxide (NO•), nitrogen dioxide (ONO-), and peroxynitrite (ONOO-)) and four ROS (superoxide anion (O2•-), hydroxyl radical (•OH), singlet oxygen (1O2), and hydrogen peroxide (H2O2)) were measured. All subjects underwent thorough clinical and routine laboratory evaluations. The main biochemical markers for disease severity were measured and correlated with the ROS and RNS levels, and they included tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), the neutrophil-to-lymphocyte ratio (NLR), and angiotensin-converting enzyme 2 (ACE2). The results indicated that the serum levels of individual ROS and RNS were significantly higher in COVID-19 patients than in healthy subjects. The correlations between the serum levels of ROS and RNS and the biochemical markers ranged from moderate to very strongly positive. Moreover, significantly elevated serum levels of ROS and RNS were observed in intensive care unit (ICU) patients compared with non-ICU patients. Thus, ROS and RNS concentrations in serum can be used as biomarkers to track the prognosis of COVID-19. This investigation demonstrated that oxidative and nitrative stress play a role in the etiology of COVID-19 and contribute to disease severity; thus, ROS and RNS are probable innovative targets in COVID-19 therapeutics.

Oxidative stress and inflammation: the root causes of aging

Oxygen free radicals [reactive oxygen species (ROS)] and nitrogen free radicals [reactive nitrogen species (RNS)] are generated by mitochondria during adenosine triphosphate synthesis, and catalytic activities of cytochrome P450, nicotinamide adenine dinucleotide phosphate oxidases (NOXs), cyclooxygenases, and nitric oxide synthases during drug catabolism, phagocytosis, and acute inflammation. Under normal circumstances, low levels of ROS and RNS provide redox signalings that control many essential physiological processes. As age progresses ROS and RNS increase excessively due to dysfunctional mitochondria, dysregulated NOX, and other free-radical generating sources, leading to oxidative stress, which causes oxidation and denaturation of key cellular components including DNA, proteins, and lipids, which become abnormal, constituting damage-associated molecular pattern (DAMP), recognized as ‘non-self’ by immune cells, leading to inflammation which is mediated by nuclear factor kappa B-inflammasome, p38-c-Jun N-terminal kinase and Janus kinase-signal transducer and activator of transcription pathways. DAMPs are continuously released from damaged and senescent cells, causing an otherwise normally transient inflammation turning into systemic chronic inflammation, the root cause of aging and age-associated diseases (AADs). Cells restore redox balance by activating the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway that induces the synthesis and release of antioxidation molecules and enzymes including haem oxygenase-1, which also inhibits the three inflammatory pathways. Furthermore, upregulation of autophagy (AP) can get rid of abnormal molecules, prevent the generation of DAMPs, and attenuate inflammation. Both AP and Nrf2 signalings decrease with age. The upregulations of Nrf2, AP, and downregulation of inflammation are controlled by sensors of energy and stress levels, i.e., adenosine monophosphate-activated protein kinase, silent information regulator 1, and Sestrins, as well as the extracellular matrix, while mammalian targets for rapamycin complex 1, a nutrient sensor, act in the opposite direction. If the balance of these sensor systems becomes dysregulated, aging process accelerates, and the risk of AADs increases.

Limited Zn supply affects nutrient distribution, carbon metabolism and causes nitro-oxidative stress in sensitive Brassica napus

Despite being a worldwide problem, responses of crops to zinc (Zn) deficiency is largely unknown. This study examines the effects of limited Zn supply in Brassica napus . The decreased Zn content of the nutrient solution caused reduced tissue Zn concentrations and reduced K, Ca, Mg levels were detected in the leaves. For Ca, Zn, Fe, Mo inhomogeneous distribution was induced by Zn limitation. Suboptimal Zn supply decreased the shoot and root biomass and altered the root structure. The levels of sugars and sugar phosphates (e.g. glucose, glucose-6-phosphate etc.) were decreased suggesting disturbance in carbon metabolism. Limited Zn availability induced organ-dependent superoxide anion and hydrogen peroxide production and triggered altered NADPH oxidase, superoxide dismutase activities, ascorbate peroxidase abundance and ascorbate and glutathione contents indicating oxidative stress. Moreover, nitric oxide, peroxynitrite and S-nitrosoglutathione (GSNO) levels and GSNO reductase gene expression, protein level and activity were modified by Zn limitation. As a consequence, protein tyrosine nitration and protein carbonylation were intensified in B. napus grown with suboptimal Zn supply. Collectively, these results provide the first evidence for Zn deficiency-induced imbalances in nutrient status, sugar contents, reactive oxygen and nitrogen species metabolisms and for the secondary nitro-oxidative stress in sensitive Brassica napus . • Brassica napus is sensitive to Zn limitation. • Zn deficiency is accompanied by disturbed nutrient homeostasis in Brassica leaves. • Zn limitation disturbs carbon metabolism indicated by reduced sugar contents. • Zn deficiency induces oxidative stress due to disturbed antioxidant defence. • Zn limitation disturbs reactive nitrogen species levels leading to nitro-oxidative stress.

Oxidative and Nitrosative Stress Detection in Human Sperm Using Fluorescent Probes.

As a natural by-product of mitochondrial respiration, reactive oxygen species (ROS) in sperm play a role in promoting fertilization, by intervening in a series of events. Nevertheless, an abnormal and uncounteracted increase in ROS production leads to oxidative stress (OS) which can, ultimately, culminate in cell death. An established relationship between OS and male infertility highlights the importance of an accurate detection method for ROS content that can be easily implemented and reproduced in any andrology lab. More recently, reactive nitrogen species (RNS) production and subsequent nitrosative stress have also been described. Here we describe the use of fluorescent probes, including some that targeted to the mitochondria due to the coupling of a cation (TPP+), in order to assess the levels of different ROS and RNS in human sperm using flow cytometry and/or fluorescent microscopy. This methodology is user friendly and accurate and can be safely applied in research- and/or clinical-based contexts.

Reactive Nitrogen Species and Male Reproduction: Physiological and Pathological Aspects.

Reactive nitrogen species (RNS), like reactive oxygen species (ROS), are useful for sustaining reproductive processes such as cell signaling, the regulation of hormonal biosynthesis, sperm capacitation, hyperactivation, and acrosome reaction. However, endogenous levels of RNS beyond physiological limits can impair fertility by disrupting testicular functions, reducing gonadotropin production, and compromising semen quality. Excessive RNS levels cause a variety of abnormalities in germ cells and gametes, particularly in the membranes and deoxyribonucleic acid (DNA), and severely impair the maturation and fertilization processes. Cell fragmentation and developmental blockage, usually at the two-cell stage, are also connected with imbalanced redox status of the embryo during its early developmental stage. Since high RNS levels are closely linked to male infertility and conventional semen analyses are not reliable predictors of the assisted reproductive technology (ART) outcomes for such infertility cases, it is critical to develop novel ways of assessing and treating oxidative and/or nitrosative stress-mediated male infertility. This review aims to explicate the physiological and pathological roles of RNS and their relationship with male reproduction.

Sustained Release of Nitric Oxide and Cascade Generation of Reactive Nitrogen/Oxygen Species via an Injectable Hydrogel for Tumor Synergistic Therapy (Adv. Funct. Mater. 36/2022)

Injectable Hydrogels In article number 2206554, Lin Yu and co-workers develop an injectable and thermosensitive hydrogel with inherent long-acting NO-releasing capacity. The hydrogel system loaded with β-lapachone and CuCys nanoparticles can synchronously boost intracellular reactive oxygen species and reactive nitrogen species levels, thereby synergistically enhancing the anti-tumor efficacy. This hydrogel is suitable as a platform for extending NO-associated medical applications.

Enzymatic and Non-Enzymatic Response during Nitrosative Stress in Escherichia coli

Abstract Nitrosative stress is an adverse physiological condition mediated by an excessive level of reactive nitrogen species (RNS). RNS react with the different macromolecules in vivo and result in the inactivation of these molecules. But the mechanism to counteract the effect of nitrosative stress is poorly understood. Escherichia coli is one of the best understood and well-studied microorganism. Although several studies have been reported on Escherichia coli to characterize the effect of various stress response but fewer works are there to see the effect of nitrosative stress. Escherichia coli encounter numerous stresses during its growth, survival, and infection. They respond to various stress conditions by activating common regulator proteins and thiols. These stress conditions result in the accumulation of these regulator proteins and thiols that allow cells to adjust to specific stress situations, conferring stress tolerance and survival. In this review, different enzymatic and non-enzymatic mechanisms to counteract the effect of nitrosative stress in Escherichia coli have been discussed and a hypothesis for the working mechanism of hybrid cluster protein that helps to combat nitrosative stress has been proposed. Here, we have tried to give a clear scenario about the mode of action of stress-responsive elements present in Escherichia coli.

Redox status of the plant cell determines epigenetic modifications under abiotic stress conditions and during developmental processes

BackgroundThe oxidation-reduction (redox) status of the cell influences or regulates transcription factors and enzymes involved in epigenetic changes, such as DNA methylation, histone protein modifications, and chromatin structure and remodeling. These changes are crucial regulators of chromatin architecture, leading to differential gene expression in eukaryotes. But the cell’s redox homeostasis is difficult to sustain since the production of reactive oxygen species (ROS) and reactive nitrogen species (RNS) is not equal in plants at different developmental stages and under abiotic stress conditions. Exceeding optimum ROS and RNS levels leads to oxidative stress and thus alters the redox status of the cell. Consequently, this alteration modulates intracellular epigenetic modifications that either mitigate or mediate the plant growth and stress response. Aim of reviewRecent studies suggest that the altered redox status of the cell reform the cellular functions and epigenetic changes. Recent high-throughput techniques have also greatly advanced redox-mediated gene expression discovery, but the integrated view of the redox status, and its associations with epigenetic changes and subsequent gene expression in plants are still scarce. In this review, we accordingly focus on how the redox status of the cell affects epigenetic modifications in plants under abiotic stress conditions and during developmental processes. This is a first comprehensive review on the redox status of the cell covering the redox components and signaling, redox status alters the post-translational modification of proteins, intracellular epigenetic modifications, redox interplay during DNA methylation, redox regulation of histone acetylation and methylation, redox regulation of miRNA biogenesis, redox regulation of chromatin structure and remodeling and conclusion, future perspectives and biotechnological opportunities for the future development of the plants. Key Scientific Concepts of ReviewThe interaction of redox mediators such as ROS, RNS and antioxidants regulates redox homeostasis and redox-mediated epigenetic changes. We discuss how redox mediators modulate epigenetic changes and show the opportunities for smart use of the redox status of the cell in plant development and abiotic stress adaptation. However, how a redox mediator triggers epigenetic modification without activating other redox mediators remains yet unknown.

Identification and Functional Analysis of GTP Cyclohydrolase II in Candida glabrata in Response to Nitrosative Stress.

Reactive nitrogen species (RNS) are signal molecules involved in various biological events; however, excess levels of RNS cause nitrosative stress, leading to cell death and/or cellular dysfunction. During the process of infection, pathogens are exposed to nitrosative stress induced by host-derived RNS. Therefore, the nitrosative stress resistance mechanisms of pathogenic microorganisms are important for their infection and pathogenicity, and could be promising targets for antibiotics. Previously, we demonstrated that the RIB1 gene encoding GTP cyclohydrolase II (GCH2), which catalyzes the first step of the riboflavin biosynthesis pathway, is important for nitrosative stress resistance in the yeast Saccharomyces cerevisiae. Here, we identified and characterized the RIB1 gene in the opportunistic pathogenic yeast Candida glabrata. Our genetic and biochemical analyses indicated that the open reading frame of CAGL0F04279g functions as RIB1 in C. glabrata (CgRIB1). Subsequently, we analyzed the effect of CgRIB1 on nitrosative stress resistance by a growth test in the presence of RNS. Overexpression or deletion of CgRIB1 increased or decreased the nitrosative stress resistance of C. glabrata, respectively, indicating that GCH2 confers nitrosative stress resistance on yeast cells. Moreover, we showed that the proliferation of C. glabrata in cultures of macrophage-like cells required the GCH2-dependent nitrosative stress detoxifying mechanism. Additionally, an infection assay using silkworms as model host organisms indicated that CgRIB1 is indispensable for the virulence of C. glabrata. Our findings suggest that the GCH2-dependent nitrosative stress detoxifying mechanism is a promising target for the development of novel antibiotics.

Alternative oxidase plays a role in minimizing ROS and RNS produced under salinity stress in Arabidopsis thaliana.

Under stress conditions, the overproduction of different reactive oxygen species (ROS) and reactive nitrogen species (RNS) causes imbalance in the redox homeostasis of the cell leading to nitro-oxidative stress in plants. Alternative oxidase (AOX) is a conserving terminal oxidase of the mitochondrial electron transport chain, which can minimize the ROS. Still, the role of AOX in the regulation of RNS during nitro-oxidative stress imposed by salinity stress is not known. Here, we investigated the role of AOX in minimizing ROS and RNS induced by 150 mM NaCl in Arabidopsis using transgenic plants overexpressing (AOX OE) and antisense lines (AOX AS) of AOX. Imposing NaCl treatment leads to a 4-fold enhanced expression of AOX accompanied by enhanced AOX capacity in WT Col-0. Further AOX-OE seedlings displayed enhanced growth compared with the AOX-AS line under stress. Examination of NO levels by DAF-FM fluorescence and chemiluminescence revealed that AOX overexpression leads to reduced levels of NO. The total NR activity was elevated under NaCl, but no significant change was observed in wild-type (WT), AOX OE, and AS lines. The total ROS, superoxide, H2 O2 levels, and lipid peroxidation were higher in the AOX-AS line than in WT and AOX-OE lines. The peroxynitrite levels were also higher in the AOX-AS line than in WT and AOX-OE lines; further, the expression of antioxidant genes was elevated in AOX-AS. Taken together, our results suggest that AOX plays an important role in the mitigation of ROS and RNS levels and enhances plant growth, thus providing tolerance against nitro-oxidative stress exerted by NaCl.

Redox-modulation, Suppression of “Oncogenic” Superoxide and Induction of Apoptosis in Burkitt’s Lymphoma Cells Using Geum urbanum L. Extracts

Burkitt’s lymphoma is a highly aggressive type of non-Hodgkin’s lymphoma, linked to the Epstein-Barr virus, which induces oxidative stress and DNA damage in the infected cells. We investigated the cytotoxicity and redox-modulating ability of ethyl acetate (EtOAc) and n-butanol (n-BuOH) extracts from Geum urbanum L. roots and aerial parts on Burkitt`s lymphoma cells (BLC), to elucidate their impact on oxidative stress and cell survival. BLC Raji was treated with EtOAc and n-BuOH extracts to analyze: cell viability; induction of apoptosis; hydroperoxides and reactive nitrogen species (RNS) by 2’,7’-dichlorodihydrofluorescein assay; superoxide by dihydroethidium assay; total antioxidant capacity by TAC assay. All extracts suppressed cell growth and induce apoptosis. n-BuOH extracts possessed higher cytotoxicity and pro-apoptotic activity compared to EtOAc. The fractions decreased the hydroperoxides and RNS levels. There was no correlation between the DCF fluorescence in the treated cells and their viability (R = -0.3722; p > 0.05). Root extracts decreased the superoxide level, while the leaf extracts did not. There was a good correlation between the dihydroethidium fluorescence in the treated cells and their viability (R = 0.9843; p < 0.01). All extracts increased the TAC of BLC. G. urbanum extracts serve as redox-modulators and anti-inflammatory compounds, decreasing the intracellular level of “oncogenic” superoxide and cell proliferation.

Amelioration of nitrosative stress to reduce pericarp browning of harvested longan by chlorine dioxide

Reactive nitrogen species (RNS) play a crucial role for plants to respond to environmental fluctuations. High formation of RNS leads to nitrosative stress and disorders in the higher plant. The use of gaseous chlorine dioxide (ClO2) treatments for postharvest application has grown in recent years due to its advantages over other methods, including its powerful antibrowning and antimicrobial activities and low environmental impacts. The purpose of this research was to determine the influence of ClO2 on RNS generation and nitrosative stress associated with browning of longan (Dimocarpus longan cv. Daw) pericarp after harvest. Longan were harvested and fumigated with ClO2 (0 and 10 mg L−1) for 10 min before being put in cardboard boxes and stored at 25±1°C for 7 d. The findings revealed that rapid pericarp browning was evident in the control at 6 h and the intensity increased steadily during storage. Browning developed in tandem with a significant rise in RNS levels (nitric oxide, nitrogen dioxide, peroxynitrite and S-nitrosoglutathione) and nitrosative stress (S-nitrosothiol, 3-nitrotyrosine, 8-nitroguanine and nitro fatty acid). Nitric oxide producing enzyme activities, including nitric oxide synthase (NOS) and nitrate reductase (NR), increased with a decline in their substrate contents (L-arginine and nitrate) and their product (L-citrulline and nitrite) and pH were also raised during severe pericarp browning. However, ClO2 fumigation reduced the activities of RNS producing enzymes and maintained their substrates for up to 5-6 d of storage. These reductions were correlated to lower RNS levels, nitrosative stress and pericarp browning, indicating that ClO2 treatment could diminish postharvest browning of ‘Daw' longan pericarp by lowering the activity of the RNS-producing enzyme, causes a reduction in RNS to counteract nitrosative stress.

Nitric Oxide Increases Mitomycin-C Cytotoxicity by Generation of Reactive Oxygen Species and Induces Cell Death by Apoptosis in FancC-/- Cells

Fanconi Anemia (FA) is a rare genetic disorder and patients of FA exhibit progressive bone marrow failure, developmental defects and cancer predisposition. Mitochondrial dysfunction due to oxidative stress and higher levels of Reactive Oxygen Species (ROS) has been well documented in FA. Increase in the levels of Reactive Nitrogen Species (RNS) and Nitric Oxide Synthase (NOS) activity is often correlated with OS- related disorders which have altered mitochondrial function. Biological effects of Nitric Oxide (NO) and nitrosative stress depend on the cell type, concentration of NO, the time of incubation and cellular homeostasis. NO is known to have both prooncogenic as well as tumour -suppressing effects which are a result of regulation of S- nitrosylation, genome wide epigenetic changes and posttranslational modification of protein. NO plays strategic roles in metabolic and signalling pathways, making NO metabolism a key mediator in pathways that are responsible for supporting tumorigenesis. NO is also known to have important regulatory roles in the process of autophagy, which is an important mediator in the cross-talk with ROS and RNS. In the present study, we examined the interaction between ROS and NO, induction of apoptosis by NO and the possible role of NO in the pathogenesis of FA. Investigating the involvement of NO and NS and their interactions with the known hallmarks of FA will give a more comprehensive understanding of pathogenesis of FA.

4-Chlorothymol Exerts Antiplasmodial Activity Impeding Redox Defense System in Plasmodium falciparum

Malaria remains one of the major health concerns due to the resistance of Plasmodium species toward the existing drugs warranting an urgent need for new antimalarials. Thymol derivatives were known to exhibit enhanced antimicrobial activities; however, no reports were found against Plasmodium spp. In the present study, the antiplasmodial activity of thymol derivatives was evaluated against chloroquine-sensitive (NF-54) and -resistant (K1) strains of Plasmodium falciparum. Among the thymol derivatives tested, 4-chlorothymol showed potential activity against sensitive and resistant strains of P. falciparum. 4-Chlorothymol was found to increase the reactive oxygen species and reactive nitrogen species level. Furthermore, 4-chlorothymol could perturb the redox balance by modulating the enzyme activity of GST and GR. 4-Chlorothymol also showed synergy with chloroquine against chloroquine-resistant P. falciparum. 4-Chlorothymol was found to significantly suppress the parasitemia and increase the mean survival time in in vivo assays. Interestingly, in in vivo assay, 4-chlorothymol in combination with chloroquine showed higher chemosuppression as well as enhanced mean survival time at a much lower concentration as compared to individual doses of chloroquine and 4-chlorothymol. These observations clearly indicate the potential use of 4-chlorothymol as an antimalarial agent, which may also be effective in combination with the existing antiplasmodial drugs against chloroquine-resistant P. falciparum infection. In vitro cytotoxicity/hemolytic assay evidently suggests that 4-chlorothymol is safe for further exploration of its therapeutic properties.

Diagnostics of a large volume pin‐to‐plate atmospheric plasma source for the study of plasma species interactions with cancer cell cultures

AbstractA large gap pin‐to‐plate, atmospheric‐pressure plasma reactor is demonstrated as means of in vitro study of plasma species interactions with cell cultures. By employing optical emission and optical absorption spectroscopy, we report that the pin‐to‐pate plasma array had an optimal discharge frequency for cell death of 1000 Hz in ambient air for the target cancer cell line, human glioblastoma multiform (U‐251MG). The detected plasma chemistry contained reactive oxygen and nitrogen species including OH, N2, N2+ and O3. We show that by varying the plasma discharge frequency, the plasma chemistry can be tailored to contain up to 8.85 times higher levels of reactive oxygen species (ROS) as well as a factor increase of up to 2.86 for levels of reactive nitrogen species (RNS). At higher frequencies, ROS are more dominant than RNS, which allows for a more dynamic and controlled environment for sample study without modifying the inducer gas conditions. When used for treatment of culture media and cell cultures, variation of the plasma discharge frequency over the range 1000–2500 Hz demonstrated a clear dependence of the responses, with the highest cytotoxic responses observed for 1000 Hz. We propose that the reactor offers a means of studying plasma–cell interactions and possible cofactors such as pro‐drugs and nanoparticles for a large volume of samples and conditions due to the use of well plates.

Altitude healing effect in severe asthmatic children

BackgroundThe beneficial effect of a climatic treatment in children with asthma was established quite some time ago, but the mechanism of this beneficial effect has not been fully elucidated. We investigated the role of the cytokines of the TH2 pathway, reactive oxygen species (ROS) and reactive nitrogen species (RNS) over the course of a high-altitude climatic therapy. MethodsA group of 67 children originating from various French towns suffering from uncontrolled severe asthma was sent via their medical specialists, to the Briançon climatic area. They were monitored over the course of an entire school year. During this time, they returned home for 15 days during the Christmas holidays. At each stage, assessment of asthma control, lung function examination (peak flow meter and spirometry), and measurement of exhaled NO, ROS and RNS in exhaled breath condensate (EBC), and the level of cytokines in the plasma of the TH2 pathway were carried out. ResultsThe degree of asthma control improved at high altitude and worsened upon returning home. The average value of the peak expiratory flow also improved during the first 3 months but then worsened upon returning home, while the other spirometric parameters did not change. The level of expired NO and the scores for quality of life underwent a similar change. The level of RNS and ROS in the EBC did not change significantly. Besides, a marked and statistically significant decrease in the level of IL-13 and IL-10 was noted. ConclusionThe beneficial effect of a climatic stay of children suffering from allergic asthma at altitude appears to be linked with less allergenic stimulation.

Cyst Nematode Infection Elicits Alteration in the Level of Reactive Nitrogen Species, Protein S-Nitrosylation and Nitration, and Nitrosoglutathione Reductase in Arabidopsis thaliana Roots.

Reactive nitrogen species (RNS) are redox molecules important for plant defense against pathogens. The aim of the study was to determine whether the infection by the beet cyst nematode Heterodera schachtii disrupts RNS balance in Arabidopsis thaliana roots. For this purpose, measurements of nitric oxide (NO), peroxynitrite (ONOO−), protein S-nitrosylation and nitration, and nitrosoglutathione reductase (GSNOR) in A. thaliana roots from 1 day to 15 days post-inoculation (dpi) were performed. The cyst nematode infection caused generation of NO and ONOO− in the infected roots. These changes were accompanied by an expansion of S-nitrosylated and nitrated proteins. The enzyme activity of GSNOR was decreased at 3 and 15 dpi and increased at 7 dpi in infected roots, whereas the GSNOR1 transcript level was enhanced over the entire examination period. The protein content of GSNOR was increased in infected roots at 3 dpi and 7 dpi, but at 15 dpi, did not differ between uninfected and infected roots. The protein of GSNOR was detected in plastids, mitochondria, cytoplasm, as well as endoplasmic reticulum and cytoplasmic membranes. We postulate that RNS metabolism plays an important role in plant defense against the beet cyst nematode and helps the fine-tuning of the infected plants to stress sparked by phytoparasitic nematodes.