Foodborne Pathogen Inactivation by Cold Plasma Reactive Species

Cold plasma is implemented in the food industry for protecting the agricultural product from foodborne pathogens. In this case, dielectric barrier discharge cold plasma pen (DBD-CP) was applied to study its efficiency in inactivation of bacterial on oyster mushroom. The surface of the fresh oyster mushroom was treated with 5 kV of AC voltage with variable of treatment times (0-4 min). Data showed sufficient energy by DBD-CPP has inactivated the existence of bacterial on the oyster mushroom surface with undetectable of bacteria colony. The reactive species generated by cold plasma undoubtedly irreversibly damage the deoxyribonucleic acid, ribonucleic acid, and enzymes of gram bacterial, which eventually causes cell death. Above all, an understanding of the microorganism cell structure, the food surface types, and roughness is an essential in manipulating cold plasma processing parameters to achieve the maximum rate of microbial inactivation.

Oxidative Stress and Antioxidant Nanotherapeutic Approaches for Inflammatory Bowel Disease

Oxidative stress, caused by the accumulation of reactive species, is associated with the initiation and progress of inflammatory bowel disease (IBD). The investigation of antioxidants to target overexpressed reactive species and modulate oxidant stress pathways becomes an important therapeutic option. Nowadays, antioxidative nanotechnology has emerged as a novel strategy. The nanocarriers have shown many advantages in comparison with conventional antioxidants, owing to their on-site accumulation, stability of antioxidants, and most importantly, intrinsic multiple reactive species scavenging or catalyzing properties. This review concludes an up-to-date summary of IBD nanomedicines according to the classification of the delivered antioxidants. Moreover, the concerns and future perspectives in this study field are also discussed.

Understanding Cellular Redox Homeostasis: A Challenge for Precision Medicine

Living organisms use a large repertoire of anabolic and catabolic reactions to maintain their physiological body functions, many of which include oxidation and reduction of substrates. The scientific field of redox biology tries to understand how redox homeostasis is regulated and maintained and which mechanisms are derailed in diverse pathological developments of diseases, where oxidative or reductive stress is an issue. The term “oxidative stress” is defined as an imbalance between the generation of oxidants and the local antioxidative defense. Key mediators of oxidative stress are reactive species derived from oxygen, nitrogen, and sulfur that are signal factors at physiological concentrations but can damage cellular macromolecules when they accumulate. However, therapeutical targeting of oxidative stress in disease has proven more difficult than previously expected. Major reasons for this are the very delicate cellular redox systems that differ in the subcellular compartments with regard to their concentrations and depending on the physiological or pathological status of cells and organelles (i.e., circadian rhythm, cell cycle, metabolic need, disease stadium). As reactive species are used as signaling molecules, non-targeted broad-spectrum antioxidants in many cases will fail their therapeutic aim. Precision medicine is called to remedy the situation.

Preparation of magnetic copper ferrite nanoparticle as peroxymonosulfate activating catalyst for effective degradation of levofloxacin

The magnetic CuFe2O4 nanoparticles were successfully synthesized with a coprecipitation method at 500 °C calcination temperature, which were utilized to degrade levofloxacin (LEV) as peroxymonosulfate (PMS) activator. The structure and composition of nanocatalyst were characterized by a series of methods, including Scanning electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, Vibrating sample magnetometer and Thermogravimetric analysis. The effect of the PMS concentration, the catalyst dosage, the LEV initial concentration, the pH value and the inorganic anions on the LEV degradation was also explored. The results revealed that the designed CuFe2O4/PMS system had high activity and excellent stability in the complex conditions. The degradation efficiency of LEV still reached above 80% after four recycles of CuFe2O4 catalyst. The reactive species quenching experiments and electron paramagnetic resonance analysis suggested the existence of superoxide radicals, single oxygen, hydroxy radicals and sulfate radicals, and the first two were dominant radical oxygen species. Based on the mechanism analyses, the efficient degradation of LEV was probably due to the continuous generation of reactive species under the condition of Fe (III)/Fe (II) and Cu (II)/Cu (I) redox cycles. The research provided a reasonable reference for the PMS activation mechanism based spinel-type ferrite catalysis.

Reactive species from aviation in the multi-scale climate-chemistry model system MECO(n)

<p>Aviation aims to reduce its climate impact by identifying promising mitigation options which are able to reduce the overall climate effects of aviation considering CO<sub>2</sub> and non-CO<sub>2</sub> effects. While aiming to identify fuel optimal trajectories, aviation also aims to reduce the non-CO<sub>2</sub> effects comprising NO<sub>x</sub>-induced changes of atmospheric ozone and methane. Here climate-chemistry models are required which are able to quantify perturbations in atmospheric composition of reactive species (NO<sub>x</sub>, O<sub>3</sub>) and the associated radiative forcings of aviation emissions relying on advanced modelling capabilities, realistic emission inventory data and global-scale observational datasets from research infrastructures like IAGOS and DLR aircraft measurement campaign data.</p> <p>We use the multi-scale climate-chemistry MECO(n) system which is a “MESSy-fied ECHAM and COSMO nested n-times”, relying on the Modular Earth Submodel System (MESSy) framework. For this purpose, both models have been equipped with the MESSy infrastructure, implying that the same process formulations (MESSy submodels) are available for both models. Modelled atmospheric distributions are systematically compared to observational data from aircraft measurements in the upper troposphere and lower stratosphere. Nudging of meteorology to ERA5 interim data, and special diagnostics available within the modular MESSy infrastructure are implemented in the numerical simulations. Online sampling along aircraft trajectories allows to extract model data with a high temporal resolution (MESSy submodel S4D), in order to evaluate model representation and key processes.</p> <p>Beyond systematic evaluation with IAGOS scheduled aircraft measurements, episodes will be evaluated where dedicated measurements from aircraft campaigns are available, comprising Spring 2014 (ML-CIRRUS campaign), early summer 2020 (Blue Sky campaign) and summer 2021 (Cirrus-HL campaign). Our analysis of reactive species, NO<sub>y</sub> and ozone, identifies those weather pattern and synoptic situations where aviation contributes strong signals, resulting in recommendations on measurement strategies to detect aviation signal in the atmosphere. We evaluate model representation of the NO<sub>x</sub>-induces effect on radiatively active species ozone and methane in both model instances, ECHAM5 and COSMO. This is key for advancing the scientific understanding of NO<sub>x</sub>-induced effects from aviation which is required in order to quantify potential compensation and trade-offs when identifying robust mitigation options for sustainable aviation.</p> <p>This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 875036 (ACACIA, Advancing the Science for Aviation and Climate) and has been supported by the DLR-Projekt Eco2Fly. This work uses measurement data from the European Research Infrastructure IAGOS/CARIBIC. High-Performance Super Computing simulations have been performed by the Deutsches Klima-Rechenzentrum (DKRZ, Hamburg) and the Leibniz-Rechenzentrum (LRZ, München).</p>

Influence of Controlling Plasma Gas Species and Temperature on Reactive Species and Bactericidal Effect of the Plasma

In this study, plasma gas species and temperature were varied to evaluate the reactive species produced and the bactericidal effect of plasma. Nitrogen, carbon dioxide, oxygen, and argon were used as the gas species, and the gas temperature of each plasma was varied from 30 to 90 °C. Singlet oxygen, OH radicals, hydrogen peroxide, and ozone generated by the plasma were trapped in a liquid, and then measured. Nitrogen plasma produced up to 172 µM of the OH radical, which was higher than that of the other plasmas. In carbon dioxide plasma, the concentration of singlet oxygen increased from 77 to 812 µM, as the plasma gas temperature increased from 30 to 90 °C. The bactericidal effect of carbon dioxide and nitrogen plasma was evaluated using bactericidal ability, which indicated the log reduction per minute. In carbon dioxide plasma, the bactericidal ability increased from 5.6 to 38.8, as the temperature of the plasma gas increased from 30 to 90 °C. Conversely, nitrogen plasma did not exhibit a high bactericidal effect. These results demonstrate that the plasma gas type and temperature have a significant influence on the reactive species produced and the bactericidal effect of plasma.

Formation of Cyclobutane Pyrimidine Dimers after UVA Exposure (Dark-CPDs) Is Inhibited by an Hydrophilic Extract of Polypodium leucotomos

Exposure to sun and especially to ultraviolet radiation (UVR) exerts well known detrimental effects on skin which are implicated in malignancy. UVR induces production of cyclobutane pyrimidine dimers (CPDs), immediately during exposure and even hours after the exposure, these latter being called dark-CPDs, as consequence of the effects of different reactive species that are formed. Fernblock® (FB), an aqueous extract of Polypodium leucotomos, has proven to have photoprotective and antioxidant effects on skin. The aim of our work was to investigate the potential photoprotective effect of FB against dark-CPD formation. Murine melanocytes (B16-F10) were exposed to UVA radiation and the production of dark-CPDs and different reactive oxygen and nitrogen species (ROS and RNS) was measured. Significant dark-CPD formation could be seen at 3h after UVA irradiation, which was inhibited by the pre-treatment of cells with FB. Formation of nitric oxide, superoxide and peroxynitrite was increased after irradiation, consistent with the increased CPD formation. FB successfully reduced the production of these reactive species. Hence, these results show how dark-CPDs are formed in UVA irradiated melanocytes, and that FB acts as a potential antioxidant and ROS scavenger, preventing the DNA damage induced by sun exposure.