Reactive Oxygen And Nitrogen Species Research Articles

Effects of Nitro-Oxidative Stress on Biomolecules: Part 1-Non-Reactive Molecular Dynamics Simulations.

Plasma medicine, or the biomedical application of cold atmospheric plasma (CAP), is an expanding field within plasma research. CAP has demonstrated remarkable versatility in diverse biological applications, including cancer treatment, wound healing, microorganism inactivation, and skin disease therapy. However, the precise mechanisms underlying the effects of CAP remain incompletely understood. The therapeutic effects of CAP are largely attributed to the generation of reactive oxygen and nitrogen species (RONS), which play a crucial role in the biological responses induced by CAP. Specifically, RONS produced during CAP treatment have the ability to chemically modify cell membranes and membrane proteins, causing nitro-oxidative stress, thereby leading to changes in membrane permeability and disruption of cellular processes. To gain atomic-level insights into these interactions, non-reactive molecular dynamics (MD) simulations have emerged as a valuable tool. These simulations facilitate the examination of larger-scale system dynamics, including protein-protein and protein-membrane interactions. In this comprehensive review, we focus on the applications of non-reactive MD simulations in studying the effects of CAP on cellular components and interactions at the atomic level, providing a detailed overview of the potential of CAP in medicine. We also review the results of other MD studies that are not related to plasma medicine but explore the effects of nitro-oxidative stress on cellular components and are therefore important for a broader understanding of the underlying processes.

Assessing Curcumin Uptake and Clearance and Their Influence on Superoxide Dismutase Activity in Drosophila melanogaster.

While normal levels of reactive oxygen and nitrogen species (RONS) are required for proper organismal function, increased levels result in oxidative stress. Oxidative stress may be managed via the scavenging activities of antioxidants (e.g., curcumin) and the action of enzymes, including superoxide dismutase (SOD). In this work, the uptake and clearance of dietary curcuminoids (consisting of curcumin, demethoxycurcumin, and bisdemethoxycurcumin) was assessed in Drosophila melanogaster larvae following chronic or acute exposure. High levels of curcuminoid uptake and loss were observed within a few hours and leveled off within eight hours post treatment onset. The addition or removal of curcuminoids from media resulted in corresponding changes in SOD activity, and the involvement of each of the three SOD genes was assessed for their contribution to total SOD activity. Taken together, these data provide insight into the uptake and clearance dynamics of curcuminoids and indicate that, while SOD activity generally increases following curcuminoid treatment, the individual SOD genes appear to contribute differently to this response.

Anticancer Effects of Plasma-Treated Water Solutions from Clinically Approved Infusion Liquids Supplemented with Organic Molecules.

Water solutions treated by cold atmospheric plasmas (CAPs) currently stand out in the field of cancer treatment as sources of exogenous blends of reactive oxygen and nitrogen species (RONS). It is well known that the balance of RONS inside both eukaryotic and prokaryotic cells is directly involved in physiological as well as pathological pathways. Also, organic molecules including phenols could exert promising anticancer effects, mostly attributed to their pro-oxidant ability in vitro and in vivo to generate RONS like O2-, H2O2, and a mixture of potentially cytotoxic compounds. By our vision of combining the efficacy of plasma-produced RONS and the use of organic molecules, we could synergistically attack cancer cells; yet, so far, this combination, to the best of our knowledge, has been completely unexplored. In this study, l-tyrosine, an amino acid with a phenolic side chain, is added to a physiological solution, often used in clinical practice (SIII) to be exposed to plasma. The efficacy of the gas plasma-oxidized SIII solution, containing tyrosine, was evaluated on four cancer cell lines selected from among tumors with poor prognosis (SHSY-5Y, MCF-7, HT-29, and SW-480). The aim was to induce tumor toxicity and trigger apoptosis pathways. The results clearly indicate that the plasma-treated water solution (PTWS) reduced cell viability and oxygen uptake due to an increase in intracellular ROS levels and activation of apoptosis pathways in all investigated cancer cells, which may be related to the activation of the mitochondrial-mediated and p-JNK/caspase-3 signaling pathways. This research offers improved knowledge about the physiological mechanisms underlying cancer treatment and a valid method to set up a prompt, adequate, and effective cancer treatment in the clinic.

Effect of lipid oxidation on the channel properties of Cx26 hemichannels: A molecular dynamics study

Intercellular communication plays a crucial role in cancer, as well as other diseases, such as inflammation, tissue degeneration, and neurological disorders. One of the proteins responsible for this, are connexins (Cxs), which come together to form a hemichannel. When two hemichannels of opposite cells interact with each other, they form a gap junction (GJ) channel, connecting the intracellular space of these cells. They allow the passage of ions, reactive oxygen and nitrogen species (RONS), and signaling molecules from the interior of one cell to another cell, thus playing an essential role in cell growth, differentiation, and homeostasis. The importance of GJs for disease induction and therapy development is becoming more appreciated, especially in the context of oncology. Studies have shown that one of the mechanisms to control the formation and disruption of GJs is mediated by lipid oxidation pathways, but the underlying mechanisms are not well understood. In this study, we performed atomistic molecular dynamics simulations to evaluate how lipid oxidation influences the channel properties of Cx26 hemichannels, such as channel gating and permeability. Our results demonstrate that the Cx26 hemichannel is more compact in the presence of oxidized lipids, decreasing its pore diameter at the extracellular side and increasing it at the amino terminus domains, respectively. The permeability of the Cx26 hemichannel for water and RONS molecules is higher in the presence of oxidized lipids. The latter may facilitate the intracellular accumulation of RONS, possibly increasing oxidative stress in cells. A better understanding of this process will help to enhance the efficacy of oxidative stress-based cancer treatments.

Comparison of plasma-activated water and free chlorine in disinfecting Escherichia coli O157:H7- and Salmonella Typhimurium-inoculated blueberry, cherry tomato, fresh-cut lettuce, and baby spinach

The concentration of reactive oxygen and nitrogen species (RONS) in plasma-activated water (PAW) can be increased by increasing the input power, discharge voltage, and discharge time under a constant discharge frequency. However, knowledge regarding RONS concentration prepared under different discharge frequencies is lacking. This study investigated how decreasing the discharge frequency affects the chemical and physical properties of PAW. The highest plasma output efficiency (57%) was observed when the discharge frequency was decreased to 200 Hz, resulting in highest concentrations of hydrogen peroxide (675 μM) and nitrate (32 mg/L), as well as highest oxidation-reduction potential (547 mV) and conductivity (870 μs/cm). Fresh-cut lettuce, baby spinach, blueberry, and cherry tomato inoculated with Escherichia coli O157:H7 and Salmonella Typhimurium were washed with 200 Hz-PAW and 10 ppm free chlorine (FC) for 1–2 min. The pathogens on the produce were inactivated by 1.8–2.5 log CFU/g using PAW, which was higher than that achieved using FC. The residual pathogens were 1.5–3.1 log CFU/mL in PAW washing water, whereas in FC water, they were inactivated below the detection limit (2 CFU/mL). Thus, decreasing the discharge frequency can increase plasma output efficiency to improve PAW properties and confirms that PAW is limited at controlling pathogen cross-contamination.

Plasma-activated water for inactivation of Salmonella Typhimurium avirulent surrogate: Applications in produce and shell egg and understanding the modes of action

Plasma-activated water (PAW) is gaining interest as a novel sanitizer for foods. However, the sanitizing efficacy of PAW varies under different conditions, and its modes of action and impacts on food quality need further investigation for it to be applied in the food industry. This study evaluated the inactivation efficacy of PAW against a Salmonella Typhimurium avirulent surrogate, investigated the underlying mechanisms, and assessed the impacts of PAW on the safety and quality of cherry tomatoes and shell eggs. PAW was effective in inactivating S. Typhimurium in a planktonic state (1.5–5.8 log CFU reduction in 2–5 min) and on the food surface (>5 log CFU reduction in 5 min). PAW prepared with deionized water vs. tap water did not differ significantly in sanitizing efficacy. Various reactive oxygen and nitrogen species (RONS) contributed to the antimicrobial property of PAW, with nitric oxide playing the most significant role. The acidic nature of PAW might synergistically affect bacteria by disrupting cell membrane and enhancing RONS permeation. PAW did not modify the visual appearance and internal pH of the treated foods. This study demonstrates that PAW has the potential to be applied as a novel sanitizer for fresh produce and egg washing.

Cold Atmospheric Pressure Plasma Jet and Plasma Lamp Interaction with Plants: Electrostimulation, Reactive Oxygen and Nitrogen Species, and Side Effects

Cold atmospheric pressure plasma (CAPP) treatment is a highly effective method of protecting seeds, plants, flowers, and trees from diseases and infection and significantly increasing crop yields. Here we found that cold atmospheric pressure He-plasma jet (CAPPJ) can also cause side effects and damage to plants if the plasma exposure time is too long. Reactive oxygen and nitrogen species (RONS), electromagnetic fields, and ultraviolet photons emitted by CAPPJ can cause both positive and negative effects on plants. CAPPJ can interact with biological tissue surfaces. The plasma lamp has no visible side effects on Aloe vera plants, cabbage, and tomatoes. A plasma lamp and a cold atmospheric pressure plasma He-jet cause strong electrical signaling in plants with a very high amplitude with frequencies equal to the frequency of plasma generation. The use of plasma lamps for electrostimulation of biological tissues can help to avoid side processes in biological tissues associated with the generation of RONS, UV photons, and direct interaction with cold plasma. CAPP technology can play an important role in agriculture, medicine, the food industry, chemistry, surface science, material science, and engineering applications without side effects if the plasma exposure is short enough.

Determinants of the maximal functional reserve during repeated supramaximal exercise by humans: The roles of Nrf2/Keap1, antioxidant proteins, muscle phenotype and oxygenation

When high-intensity exercise is performed until exhaustion a “functional reserve” (FR) or capacity to produce power at the same level or higher than reached at exhaustion exists at task failure, which could be related to reactive oxygen and nitrogen species (RONS)-sensing and counteracting mechanisms. Nonetheless, the magnitude of this FR remains unknown. Repeated bouts of supramaximal exercise at 120% of VO2max interspaced with 20s recovery periods with full ischaemia were used to determine the maximal FR. Then, we determined which muscle phenotypic features could account for the variability in functional reserve in humans. Exercise performance, cardiorespiratory variables, oxygen deficit, and brain and muscle oxygenation (near-infrared spectroscopy) were measured, and resting muscle biopsies were obtained from 43 young healthy adults (30 males). Males and females had similar aerobic (VO2max per kg of lower extremities lean mass (LLM): 166.7 ± 17.1 and 166.1 ± 15.6 ml kg LLM−1.min−1, P = 0.84) and anaerobic fitness (similar performance in the Wingate test and maximal accumulated oxygen deficit when normalized to LLM). The maximal FR was similar in males and females when normalized to LLM (1.84 ± 0.50 and 2.05 ± 0.59 kJ kg LLM−1, in males and females, respectively, P = 0.218). This FR depends on an obligatory component relying on a reserve in glycolytic capacity and a putative component generated by oxidative phosphorylation. The aerobic component depends on brain oxygenation and phenotypic features of the skeletal muscles implicated in calcium handling (SERCA1 and 2 protein expression), oxygen transport and diffusion (myoglobin) and redox regulation (Keap1). The glycolytic component can be predicted by the protein expression levels of pSer40-Nrf2, the maximal accumulated oxygen deficit and the protein expression levels of SOD1. Thus, an increased capacity to modulate the expression of antioxidant proteins involved in RONS handling and calcium homeostasis may be critical for performance during high-intensity exercise in humans.

Effect of Humidity on the Inactivation of Bacillus Subtilis Spore by Non-thermal Atmospheric Air Plasma

Objective: If a medical device is not properly disinfected, it will pose a potential danger to patients. Spore is an experimental strain to verify the effect of disinfection on medical devices. It has a complex structure and is somewhat resistant to conventional disinfection techniques. Based on the advantages of simple structure and abundant reactive oxygen and nitrogen species (RONS), surface dielectric barrier discharge (SDBD) has been used to deal with inactivate spores, which provided experimental support for the application of sterilization spores in medical devices. Methods: The sterilization efficiency of the plasma was evaluated by calculating the number of viable colonies on Tryptose Soya Agar. RONS including ozone, nitrogen oxides and other reactive species produced in SDBD were measured by ozone analyzer, Fourier infrared spectrometer and chemical probes, respectively. Ultraviolet-visible spectrophotometer was used to determine the concentration of protein and nucleic acid. Results: After 20min of SDBD treatment, the number of inactivated spores could reach more than 4 log at high humidity (>6g/m3), while the spores were hardly inactivated at low humidity (<6g/m3). Ozone production was inhibited with increasing humidity while OH radicals and peroxynitrous acid increased with increasing humidity. The optical density values of protein and nucleic acid released from spores treated with SDBD was detected and a strong correlation was found with the spore inactivation trend. The protein shell and membrane structure of the spores were destroyed by SDBD, and more leakage and destruction of proteins and nucleic acids in the spores were obtained under the high humidity. Conclusion: With the increase of air humidity (from 0.15g/m3 to 70.16g/m3), stable SDBD is obtained showing a typical filamentous discharge pattern. Compared with low humidity, high humidity is more favorable to SDBD inactivation of spores.

Different RONS Generation in MTC-SK and NSCL Cells Lead to Varying Antitumoral Effects of Alpha-Ketoglutarate + 5-HMF.

Carbonylated proteins (CPs) serve as specific indicators of increased reactive oxygen and nitrogen species (RONS) production in cancer cells, attributed to the dysregulated mitochondrial energy metabolism known as the Warburg effect. The aim of this study was to investigate the potential of alpha-ketoglutarate (aKG), 5-hydroxymethylfurfural (5-HMF), and their combination as mitochondrial-targeting antioxidants in MTC-SK or NCI-H23 cancer cells. MTC-SK and NCI-H23 cells were cultured in the absence or presence of varying concentrations (0-500 µg/mL) of aKG, 5-HMF, and the combined aKG + 5-HMF solutions. After 0, 24, 48, and 72 h, mitochondrial activity, cancer cell membrane CP levels, cell growth, and caspase-3 activity were assessed in aliquots of MTC-SK and NCI-H23 cells. The mitochondrial activity of MTC-SK cells exhibited a concentration- and time-dependent reduction upon treatment with aKG, 5-HMF, or the combined aKG + 5-HMF. The half-maximal inhibitory concentration (IC50%) for mitochondrial activity was achieved at 500 µg/mL aKG, 200 µg/mL 5-HMF, and 200 µg/mL aKG + 66.7 µg/mL 5-HMF after 72 h. In contrast, NCI-H23 cells showed a minimal reduction (10%) in mitochondrial activity even at the highest combined concentration of aKG + 5-HMF. The CP levels in MTC-SK cells were measured at 8.7 nmol/mg protein, while NCI-H23 cells exhibited CP levels of 1.4 nmol/mg protein. The combination of aKG + 5-HMF led to a decrease in CP levels specifically in MTC-SK cells. The correlation between mitochondrial activity and CP levels in the presence of different concentrations of combined aKG + 5-HMF in MTC-SK cells demonstrated a linear and concentration-dependent decline in CP levels and mitochondrial activity. Conversely, the effect was less pronounced in NCI-H23 cells. Cell growth of MTC-CK cells was reduced to 60% after 48 h and maintained at 50% after 72 h incubation when treated with 500 µg/mL aKG (IC50%). Addition of 500 µg/mL 5-HMF inhibited cell growth completely regardless of the incubation time. The IC50% for 5-HMF on MTC-CK cell growth was calculated at 375 µg/mL after 24 h incubation and 200 µg/mL 5-HMF after 72 h. MTC-SK cells treated with 500 µg/mL aKG + 167 µg/mL 5-HMF showed no cell growth. The calculated IC50% for the combined substances was 250 µg/mL aKG + 83.3 µg/mL 5-HMF (48 h incubation) and 200 µg/mL aKG + 66.7 µg/mL 5-HMF (72 h incubation). None of the tested concentrations of aKG, 5-HMF, or the combined solution had any effect on NCI-H23 cell growth at any incubation time. Caspase-3 activity increased to 21% in MTC-CK cells in the presence of 500 µg/mL aKG, while an increase to 59.6% was observed using 500 µg/mL 5-HMF. The combination of 500 µg/mL aKG + 167.7 µg/mL 5-HMF resulted in a caspase-3 activity of 55.2%. No caspase-3 activation was observed in NCI-H23 cells when treated with aKG, 5-HMF, or the combined solutions. CPs may serve as potential markers for distinguishing between cancer cells regulated by RONS. The combination of aKG + 5-HMF showed induced cell death in high-RONS-generating cancer cells compared to low-RONS-generating cancer cells.

A reactive oxygen/nitrogen species-eliminating natural product-based nanomedicine for prevention and treatment of inflammatory liver injury

Reactive oxygen and nitrogen species (RONS) are key signaling molecules that play an important role in the progression of inflammatory diseases. Although various antioxidants have RONS scavenging properties, they are difficult to be used to cope with acute inflammation which requires inflammatory site-targeting, effective anti-inflammatory activity, and low toxicity. In this work, we developed a safe and effective nano-antioxidant ZMF formed by simply self-assembly of natural plant protein zein and natural drug mangiferin for the synergistic treatment of inflammation-related acute liver injury. ZMF could eliminate RONS, inhibit the activation of macrophages, and modulate the level of inflammatory cytokines through the synergistic effects of mangiferin and zein. In addition, in the mouse models of inflammation-related acute liver injury, ZMF showed superior efficacy in reducing inflammatory reactions. Importantly, the preliminary in vitro and in vivo experiments proved the good safety of ZMF. This study proved the remarkable anti-inflammatory activities of nanomedicine self-assembled by RONS-eliminating natural products, which could provide a reference for the green development of efficient nano-antioxidant from natural products for the treatment of inflammation-related diseases.

Plasma-Activated Water: Physicochemical Properties, Generation Techniques, and Applications

Plasma-activated water (PAW) is water that has been treated with atmospheric pressure plasma. Due to the presence of reactive oxygen and nitrogen species (RONS), PAW can be used in various applications such as (1) surface disinfection and food decontamination, (2) enhancement in seed germination, and (3) enhancement in surface cooling in the nucleate boiling regime. Briefly, for surface disinfection, the reactive species in PAW can induce oxidative stress on microbes; for enhancement of seed germination, the reactive species in PAW can trigger seed germination and provide nutrients; for enhancement in surface cooling, the reactive species cause a reduction in the surface tension of PAW, facilitating the phase-change heat transfer and, quite unexpectedly, minimizing the surface oxidation. Here, we review the physicochemical properties of PAW, the three commonly used techniques (plasma jet, dielectric barrier discharge, and corona discharge) for generating atmospheric pressure plasma, and the use of PAW for the above three applications. In particular, we review the recent development of the miniaturization of the plasma generator integrated with an acoustic neutralizer to produce plasma-activated aerosols, elimination of the need for storage, and the interesting physicochemical properties of PAW that lead to cooling enhancement.

3-Indolepropionic acid mitigates sub-acute toxicity in the cardiomyocytes of epirubicin-treated female rats.

Epirubicin (EPI) is an effective chemotherapeutic against breast cancer, though EPI-related cardiotoxicity limits its usage. Endogenously derived 3-indolepropionic acid (3-IPA) from tryptophan metabolism is of interest due to its antioxidant capabilities which may have cardioprotective effects. Supplementation with 3-IPA may abate EPI's cardiotoxicity, and herein we studied the possibility of lessening EPI-induced cardiotoxicity in Wistar rats. Experimental rats (n = 30; BW 180-200g) were randomly distributed in five cohorts (A-E; n = 6 each). Group A (control), Group B (EPI 2.5mg/mL), and group C (3-IPA 40mg/kg) while Groups D and E were co-treated with EPI (2.5mg/mL) together with 3-IPA (D: 20 and E: 40mg/kg). Following sacrifice, oxidative status, lipid profile, transaminases relevant to cardiac function, and inflammatory biomarkers were analysed. Also, 8-hydroxyl-2'-deoxyguanosine (8-OHdG) and cardiac troponin T (cTnT) levels were assessed using an enzyme-linked immunosorbent assay (ELISA). EPI-initiated increases in cardiotoxicity biomarkers were significantly (p < 0.05) reduced by 3-IPA supplementation. Decreased antioxidant and increases in reactive oxygen and nitrogen species (RONS), 8-OHdG and lipid peroxidation were lessened (p < 0.05) in rat hearts co-treated with 3-IPA. EPI-induced increases in nitric oxide and myeloperoxidase were reduced (p < 0.05) by 3-IPA co-treatment. In addition, 3-IPA reversed EPI-mediated alterations in alanine aminotransferase (ALT), aspartate amino transaminases (AST), lactate dehydrogenase (LDH), cardiac troponin T (cTnT), and serum lipid profile including total cholesterol and triglycerides. Microscopic examination of the cardiac tissues showed that histopathological lesions severity induced by EPI was lesser in 3-IPA co-treated rats. Our findings demonstrate that supplementing endogenously derived 3-IPA can enhance antioxidant protection in the cardiac tissue susceptible to EPI toxicity in female rats. These findings may benefit breast cancer patients undergoing chemotherapy by further validating these experimental data.

Efficient treatment of bio-contaminated wastewater using plasma technology for its reuse in sustainable agriculture

Water-related crisis represents one of the significant challenges of the rapidly growing world population. This study demonstrates an example of the novel technology of Non-Thermal Plasma (NTP) wastewater treatment for its sustainable recovery and reuse in agriculture. NTP treatment of wastewater not only causes microbial decontamination but produces Reactive Oxygen and Nitrogen Species (RONS), which can consequently improve seed germination and plant growth. We investigated the effects of the new Fountain Dielectric Barrier Discharge air plasma reactor for the treatment of bulk quantity water contaminated by Staphylococcus epidermidis or Escherichia coli bacteria. Then, employing the treated water for barley seed germination showed >20% enhancement compared to using tap water. The inactivation of bacteria in water was determined in dependence on pH, Oxidation-Reduction Potential, and correlated with chemical RONS produced in the water (hydrogen peroxide, nitrites, and especially nitrates). By utilizing the Responses Surface Methodology, we identified the optimal plasma treatment time per litre required for efficient RONS production and bactericidal effect in the wastewater treatment, which was linearly scalable with water volume. After the optimum plasma treatment time, a sharp drop in pH, and the concentrations of nitrites and hydrogen peroxide were observed, which is related to the peroxynitrite formation leading to the significant bacterial reduction up to 7-log.

An RNA modification enzyme directly senses reactive oxygen species for translational regulation in Enterococcus faecalis

Bacteria possess elaborate systems to manage reactive oxygen and nitrogen species (ROS) arising from exposure to the mammalian immune system and environmental stresses. Here we report the discovery of an ROS-sensing RNA-modifying enzyme that regulates translation of stress-response proteins in the gut commensal and opportunistic pathogen Enterococcus faecalis. We analyze the tRNA epitranscriptome of E. faecalis in response to reactive oxygen species (ROS) or sublethal doses of ROS-inducing antibiotics and identify large decreases in N2-methyladenosine (m2A) in both 23 S ribosomal RNA and transfer RNA. This we determine to be due to ROS-mediated inactivation of the Fe-S cluster-containing methyltransferase, RlmN. Genetic knockout of RlmN gives rise to a proteome that mimics the oxidative stress response, with an increase in levels of superoxide dismutase and decrease in virulence proteins. While tRNA modifications were established to be dynamic for fine-tuning translation, here we report the discovery of a dynamically regulated, environmentally responsive rRNA modification. These studies lead to a model in which RlmN serves as a redox-sensitive molecular switch, directly relaying oxidative stress to modulating translation through the rRNA and the tRNA epitranscriptome, adding a different paradigm in which RNA modifications can directly regulate the proteome.

The Fabrication of a La2Sn2O7/f-HNT Composite for Non-Enzymatic Electrochemical Detection of 3-Nitro-l-tyrosine in Biological Samples.

Reactive oxygen and nitrogen species (RONS), including 3-nitro-l-tyrosine, play a dual role in human health, inducing oxidative damage and regulating cellular functions. Early and accurate detection of such molecules, such as L-tyrosine in urine, can serve as critical biomarkers for various cancers. In this study, we aimed to enhance the electrochemical detection of these molecules through the synthesis of La2Sn2O7/f-HNT nanocomposites via a simple hydrothermal method. Detailed structural and morphological characterizations confirmed successful synthesis, consistent with our expected outcomes. The synthesized nanocomposites were utilized as nanocatalysts in electrochemical sensors, showing a notable limit of the detection of 0.012 µM for the real-time detection of 3-nitro-l-tyrosine. These findings underscore the potential of nanomaterial-based sensors in advancing early disease detection with high sensitivity, furthering our understanding of cellular oxidative processes.

Numerous Trigger-like Interactions of Kinases/Protein Phosphatases in Human Skeletal Muscles Can Underlie Transient Processes in Activation of Signaling Pathways during Exercise.

Optimizing physical training regimens to increase muscle aerobic capacity requires an understanding of the internal processes that occur during exercise that initiate subsequent adaptation. During exercise, muscle cells undergo a series of metabolic events that trigger downstream signaling pathways and induce the expression of many genes in working muscle fibers. There are a number of studies that show the dependence of changes in the activity of AMP-activated protein kinase (AMPK), one of the mediators of cellular signaling pathways, on the duration and intensity of single exercises. The activity of various AMPK isoforms can change in different directions, increasing for some isoforms and decreasing for others, depending on the intensity and duration of the load. This review summarizes research data on changes in the activity of AMPK, Ca2+/calmodulin-dependent protein kinase II (CaMKII), and other components of the signaling pathways in skeletal muscles during exercise. Based on these data, we hypothesize that the observed changes in AMPK activity may be largely related to metabolic and signaling transients rather than exercise intensity per se. Probably, the main events associated with these transients occur at the beginning of the exercise in a time window of about 1-10 min. We hypothesize that these transients may be partly due to putative trigger-like kinase/protein phosphatase interactions regulated by feedback loops. In addition, numerous dynamically changing factors, such as [Ca2+], metabolite concentration, and reactive oxygen and nitrogen species (RONS), can shift the switching thresholds and change the states of these triggers, thereby affecting the activity of kinases (in particular, AMPK and CaMKII) and phosphatases. The review considers the putative molecular mechanisms underlying trigger-like interactions. The proposed hypothesis allows for a reinterpretation of the experimental data available in the literature as well as the generation of ideas to optimize future training regimens.

Plasma-generated nitric oxide radical (NO•) promotes the proliferation of fibroblast cells in liquid

The promotion of cell proliferation by non-equilibrium atmospheric-pressure plasma is a promising technology for regenerative medicine. The fibroblast suspension was irradiated with electrically neutral radicals. Radial irradiation was performed using an atmospheric-pressure radical generator with a working gas mixture of Ar, O2, and N2. Carboxy-PTIO (c-PTIO), a scavenger of nitric oxide radical (NO•), was dissolved in the fibroblast suspension. Selective irradiation with electrically neutral radicals promoted fibroblast proliferation by 36% without c-PTIO in liquid. In contrast, proliferation-promoting effects were significantly reduced to 13% with c-PTIO. Fluorescence probes for reactive oxygen and nitrogen species (RONS) and NO• showed that intracellular RONS and NO• levels were increased by radical irradiation and reduced with c-PTIO in the fibroblast suspension. NO• was detected in the radical-irradiated solutions using ERS. These results suggested that plasma-generated NO• promotes fibroblast proliferation in liquids.

Bactericidal efficacy difference between air and nitrogen cold atmospheric plasma on Bacillus cereus: Inactivation mechanism of Gram-positive bacteria at the cellular and molecular level

As an emerging food processing technology, cold atmospheric plasma (CAP) has attracted great attention in the field of microbial inactivation. Although CAP has been proven to effectively inactivate a variety of foodborne pathogens, there is less research on the inactivation of Bacillus cereus, and the exact inactivation mechanism is still unclear. Elucidating the inactivation mechanism will help to develop and optimize this sterilization method, with the prospective application in industrialized food production. This study aims to explore the bactericidal efficacy difference between air and nitrogen CAP on B. cereus, a typical Gram-positive bacterium, and reveals the inactivation mechanism of CAP at the cellular and molecular level, by observing the change of the cell membrane, cell morphological damage, intracellular antioxidant enzyme activity and cellular biomacromolecules changes. The results showed that both air CAP and nitrogen CAP could effectively inactivate B. cereus, which was due to the reactive oxygen and nitrogen species (RONS) generated by the plasma causing bacterial death. The damage pathways of CAP on Gram-positive bacteria could be explained by disrupting the bacterial cell membrane and cell morphology, disturbing the intracellular redox homeostasis, and destroying biomacromolecules in the cells. The differences in active species generated by the plasma were the main reason for the different bactericidal efficiencies of air CAP and nitrogen CAP, where air CAP producing RONS with stronger oxidative capacity in a shorter time. This study indicates that air CAP is an effective, inexpensive and green technology for B. cereus inactivation, providing a basis for industrial application in food processing.

Unraveling the Transport Properties of RONS across Nitro-Oxidized Membranes.

The potential of cold atmospheric plasma (CAP) in biomedical applications has received significant interest, due to its ability to generate reactive oxygen and nitrogen species (RONS). Upon exposure to living cells, CAP triggers alterations in various cellular components, such as the cell membrane. However, the permeation of RONS across nitrated and oxidized membranes remains understudied. To address this gap, we conducted molecular dynamics simulations, to investigate the permeation capabilities of RONS across modified cell membranes. This computational study investigated the translocation processes of less hydrophilic and hydrophilic RONS across the phospholipid bilayer (PLB), with various degrees of oxidation and nitration, and elucidated the impact of RONS on PLB permeability. The simulation results showed that less hydrophilic species, i.e., NO, NO2, N2O4, and O3, have a higher penetration ability through nitro-oxidized PLB compared to hydrophilic RONS, i.e., HNO3, s-cis-HONO, s-trans-HONO, H2O2, HO2, and OH. In particular, nitro-oxidation of PLB, induced by, e.g., cold atmospheric plasma, has minimal impact on the penetration of free energy barriers of less hydrophilic species, while it lowers these barriers for hydrophilic RONS, thereby enhancing their translocation across nitro-oxidized PLB. This research contributes to a better understanding of the translocation abilities of RONS in the field of plasma biomedical applications and highlights the need for further analysis of their role in intracellular signaling pathways.