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Combatting the antigenicity of common ragweed pollen and its primary allergen Amb a 1 with cold atmospheric pressure air plasma

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Cold atmospheric plasma (CAP) has been widely applied for microbe inactivation. Previous studies revealed that the inactivation efficiency could be improved with the sequential use of plasma-activated water (PAW) after the direct CAP treatment, while the mechanism requires further exploration. In this work, we employed a CAP jet device and investigated the inactivation effect of CAP combined with PAW treatment on two kinds of fungi (Saccharomyces cerevisiae and Aspergillus flavus), and particularly, we examined the synergistic effect by scrutinizing the roles of varied reactive species. Our experimental results showed that short-term CAP treatment combined with the continued long-term (e.g., 120 min) PAW treatment led to about significant reduction of Saccharomyces cerevisiae/Aspergillus flavus, with the disinfection effect equivalent to the single CAP approach with much longer treatment time. The comparative analysis revealed that the inactivation of fungi was induced by different reactive oxygen and nitrogen species (RONS) during the combination of CAP and PAW treatments, which had different influences on the fungal morphology, membrane permeability, intracellular RONS and energy metabolism. In the first stage of CAP treatment, the plasma produced ·OH and ¹O2, could directly destroy the structure of fungal wall and membrane, leading to cell death. While in the subsequent PAW treatment, the reactive nitrogen species (RNS) could enter cell and influence metabolic activities, leading inactivation of more fungi. The synergistic effect was attributed to the increasing of intracellular ¹O2 and ONOO⁻ induced membrane damage, causing the irreparable oxidative damage to mitochondria and energy metabolic system. This mechanistic study may thus provide a new guidance for the optimal application of low-temperature plasma technology in the application of fungal disinfection with high efficiency.
Article
In this study, soy protein isolate (SPI) was treated by modified atmosphere packaging (MAP) assisted dielectric barrier discharge (DBD) cold plasma (CP) to improve its functional properties. For this reason, SPI powders were treated with DBD-CP at the oxygen ratio of 20%, 30%, 40%, 50% and 60%, respectively. The results showed that with the increase of oxygen content, the structure of SPI was destroyed, protein macromolecule depolymerized. However, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) confirmed that the primary structure of SPI was not disrupted. In addition, when the oxygen content was greater than 40%, the solubility, water holding capacity, gelling, emulsifying and foaming properties of SPI were significantly improved (p<0.05). The results showed that high-oxygen packaging can increase the active particles generated during processing, thereby optimizing the structural and functional properties of SPI. Therefore, MAP can serve as a more efficient method for DBD-CP to modify soybean protein.
Article
The effect of atmospheric pressure cold plasma was investigated on jackfruit seed flour (JSF) for functionality modification. Dynamic radicals and reactive species of cold plasma tend to initiate effective interactions with the food matrix which incur significant changes in the properties. The prepared jackfruit seed flour was treated with varying plasma voltages of 170, 200, and 230 V for 5–15 min and then analyzed for various physicochemical (Moisture, pH, flour compressibility, color) and functional properties (Water holding capacity, water/oil binding capacity, gel hydration properties). The modification in the morphology with increased surface roughness, loss in the degree of crystallinity (25.75% to 21.31%), and starch-protein modifications were observed after plasma treatment with the increase in the intensity of plasma at higher input voltage and exposure time. Because of this, the increase in the hydration properties such as water solubility (9.65 g/g to 14.11 g/g), absorption (6.39 g/g to 7.66 g/g), swelling power (7.28 g/g to 8.79 g/g), water-holding (2.93 g/g to 3.48 g/g), and flowability (reduction in Hausner's ratio), decrease in the pH (6.59 to 6.05), moisture (8.14% to 5.26%), and paste viscosity was acquired. Such modified properties unfold wide application opportunities for the treated JSF. Thus, cold plasma treatment was identified as a potential technology for functionality modification to employ the underutilized ingredients.
Article
This study aimed to investigate the effect of atmospheric pressure non-thermal pin-to-plate plasma on the functional, rheological, thermal, and morphological properties of mango seed kernel starch. As cold plasma contains highly reactive species and free radicals, it is expected to cause noticeable modifications in the attributes of starch treated. The isolated mango seed kernel starch was subjected to the plasma treatment of input voltages 170 and 230 V for 15 and 30 min of exposure. Water adsorption, swelling, and solubility at lower temperatures. There has been a significant reduction (p < 0.05) in pH values of starch from 7.09 to 6.16 and also the desirable reduction in turbidity values by 42.60%. However, there has been no significant change in the oil and water binding behavior of the starch. The FTIR spectra of MSKS demonstrate the formation of amines which contributes to the better hydrophilic nature of the starch. The structural modification has been adequately confirmed by SEM images. The maximum voltage and time combination, lead to depolymerization of starch which is supported by NMR spectra thus affecting thermal and rheological properties. The application of cold plasma-modified MSKS in food would facilitate stable and smooth textural development.
Article
While atmospheric cold plasma has successfully inactivated biohazardous proteinaceous molecules (unwanted enzymes, prions, and allergens) and modified proteins with improved functionality, few studies have characterized plasma-protein interactions. This study investigates the physicochemical interactions, structural alteration, and reaction mechanisms of bovine serum albumin (BSA) subjected to high voltage atmospheric cold plasma (HVACP) generated by a dielectric barrier discharge in sealed bags packed with air or modified air (65% O2, 30% N2, 5% CO2). Treating 10 mL of BSA solution (50 mg/mL) with HVACP for 60 min changed the sample from transparent to yellow and induced protein precipitation. HVACP also induced protein unfolding, altered secondary structure (27% loss of α-helix), and increased disorder structure (10% increase of random coil). HVACP-treated protein increased in average size from 10 nm to 113 μm, with a broader size distribution after 60 min of HVACP treatment. SDS-PAGE and mass spectrometry showed the formation of new peptides from 1 to 10 kDa, indicating plasma-triggered peptide bond cleavage. Chemical analysis and mass spectrometry demonstrated oxidation and deamidation in HVACP-treated samples. This study illustrates that interactions between HVACP-induced reactive species and proteins may introduce structural alterations, protein aggregation, peptide cleavage, and side-group modifications to proteins in aqueous conditions.
Article
Pollen allergens, widely present in the atmosphere, are the main cause of seasonal respiratory diseases that affect millions of people worldwide. Although previous studies have reported that nitrogen dioxide (NO2) and ozone (O3) promote pollen allergy, the specific biological processes and underlying mechanisms remain less understood. In this study, Platanus pollen grains were exposed to gaseous pollutants (NO2 and O3). We employed environmental electron microscopy, flow cytometry, western blot assay, enzyme-linked immunoassay, ultraviolet absorption spectrometry, circular dichroism, and protein mass spectrometry to characterise the subpollen particles (SPPs) released from pollen grains. Furthermore, we determined the immunogenicity and pathogenicity induced by Platanus pollen allergen a 3 (Pla a 3). Our results demonstrated that NO2 and O3 could damage the pollen cell membranes in SPPs and increase the amount of Pla a 3 allergen released into the atmosphere. Additionally, NO2 and O3 altered the structure of Pla a3 protein through nitrification and oxidation, which not only enhanced the immunogenicity of allergens but also increased the stability of the protein. In vivo analysis using an animal model indicated that NO2 and O3 greatly aggravated pollen-induced pneumonia. Thus, our study provides guidance for the prevention of pollen allergic diseases.
Article
Casein, β-lactoglobulin and α-lactalbumin are major milk protein allergens. In the present study, the structural modifications and antigenic response of these bovine milk allergens as induced by non-thermal treatment by atmospheric cold plasma were investigated. Spark discharge (SD) and glow discharge (GD), as previously characterized cold plasma systems, were used for protein treatments. Casein, β-lactoglobulin and α-lactalbumin were analyzed before and after plasma treatment using SDS-PAGE, FTIR, UPLC-MS/MS and ELISA. SDS-PAGE results revealed a reduction in the casein and α-lactalbumin intensity bands after SD or GD treatments; however, the β-lactoglobulin intensity band remained unchanged. FTIR studies revealed alterations in protein secondary structure induced by plasma, particularly contents of β-sheet and β-turn. The UPLC-MS/MS results showed that the amino acid compositions decreased after plasma treatments. ELISA of casein and α-lactalbumin showed a decrease in antigenicity post plasma treatment, whereas ELISA of β-lactoglobulin showed an increase in antigenicity. The study indicates that atmospheric cold plasma can be tailored to mitigate the risk of bovine milk allergens in the dairy processing and ingredients sectors.
Article
Fungal contamination is a concern for the food industry. Fungal spores resist food sterilization treatments and produce mycotoxins that are toxic for animals and humans. Technologies that deactivate spores and toxins without impacting food quality are desirable. This study demonstrates the efficiency of a high voltage atmospheric cold plasma (HVACP) technology using air to generate reactive oxygen (ROS) and nitrogen (RNS) species for the degradation of Aspergillus flavus cultures and the deoxynivalenol (DON) mycotoxin. Optical emission and absorption spectroscopy demonstrate ionization of hydroxyl groups, atomic oxygen and nitrogen, and confirm production of ROS and RNS, e.g. O3, NO2, NO3, N2O4, and N2O5. Fungal cultures show a depletion in pigmentation and an ~50% spore inactivation after 1-min treatments. Treated spores show surface ablation and membrane degradation by scanning electron microscopy. Twenty-minute direct HVACP treatments of 100 μg of DON in one mL aqueous suspensions resulted in a greater than 99% reduction in DON structure and rescued over 80% of Caco-2 cell viability; however, the same treatment on 100 μg of powdered DON toxin only showed a 33% reduction in DON and only rescued 15% of cell viability. In summary, HVACP air treatment can inactivate both fungal spores and toxins in minutes.
Article
Vibrational spectroscopy was applied to determine macronutrient levels, total polyphenols (TPs) content, antioxidant activity, pH and color parameters in bee pollens. Raman, attenuated total reflection and diffuse reflectance spectra in the mid- and near-infrared regions were recorded for the homogenized pollen granules. Combining spectral data and the results of reference analyses, partial least squares (PLS) models were constructed and validated. The relative standard errors of prediction (RSEP) were calculated for the calibration and validation sets. Regarding macronutrient analysis, the latter were found to be in the 1.7-2.3%, 2.5-3.6% and 2.6-3.3% ranges for protein, reducing sugars and fat determination, respectively. These errors amounted to 3.1-3.5% for TPs and 2.2-3.4% for antioxidant activity quantification, respectively, whereas they were found to be in the 1.5-2.3% and 1.6-3.2% ranges for pH and the color parameters' determination.
Article
Since the initial discovery of aeroallergens in the 20th century, our understanding of their properties including sources and factors influencing their spread continues to expand. Both habits of daily living and the presence of environmental factors such as exposure to animals or pollution can influence susceptibility to atopic disease. Because relevant allergens may vary in individuals and communities, it is necessary to understand the physical properties of environmental aeroallergens that are associated with clinical disease to explain symptoms and to implement successful integrated interventions. The objective of this review was to present an overview of aeroallergens and the environmental factors influencing their current distribution. Using historical studies along with recent advancements, we will give an up-to-date description of the physical characteristics and aerodynamics of aeroallergens in addition to location, quantities, and timing of exposure.
Article
Cold plasma is an emerging technology increasingly applied in the agri-food industry. For fruit and vegetables, enzymatic browning is a common phenomenon, causing quality deterioration. The objective of this study was to illustrate the effect of microscale atmospheric-pressure plasma jet (µAPPJ) plasma on the horseradish peroxidase (HRP). Results showed that after plasma treatment for 10 min, the residual activity of HRP was decreased to around 17%, and modification of secondary and tertiary structures were confirmed. The atomic force microscope (AFM) analysis revealed that the aggregation of enzyme protein was enhanced with prolonging treatment time. It was concluded that the activity of HRP could be reduced with destruction of structures and deformation of microstructure induced by µAPPJ plasma. The current study attempted to provide new idea for inhibiting browning enzymes of fruit and vegetables with plasma technology through deeper understanding of the interaction mechanism of plasma active species with enzymes.
Article
Tropomyosin (TM), a myofibrillar protein, is a major allergen in most crustaceans including king pawn (Litopenaeus vannamei). In this study, the structural modifications and allergenic response of TM in fresh king prawn as induced by cold argon plasma jet (CAPJ) were examined. The result showed that the level of α-helix structures declined as treatment time progressed, while the level of β-sheets and random coils increased. The free sulfhydryl groups decreased as CAPJ treatment progressed due to the formation of disulphide bonds while surface hydrophobicity increased until equilibrium values. In addition, after 15 min of plasma exposure, the maximum reduction recorded for IgE and IgG binding capacities were 17.6% and 26.87% respectively as revealed by ELISA test. These findings correlated with the occurrence of protein unfolding and denaturation, evident by complementary structural analyses conducted. The study indicates that non-thermal plasma maybe a promising tool for developing hypoallergenic food products.
Article
Common ragweed is a highly allergenic invasive species in Europe, expected to become widespread under climate change. Allergy to ragweed manifests as eye, nasal and lung symptoms, and children may retain these throughout life. The dose-response relationship between symptoms and pollen concentrations is unclear. We undertook a longitudinal study, assessing the association between ragweed pollen concentration and allergic eye, nasal and lung symptoms in children living under a range of ragweed pollen concentrations in Croatia. Over three years, 85 children completed daily diaries, detailing allergic symptoms alongside daily location, activities and medication, resulting in 10,130 individual daily entries. The daily ragweed pollen concentration for the children's locations was obtained, alongside daily weather and air pollution. Parents completed a home/lifestyle/medical questionnaire. Generalised Additive Mixed Models established the relationship between pollen concentrations and symptoms, alongside other covariates. Eye symptoms were associated with mean daily pollen concentration over four days (day of symptoms plus 3 previous days); 61 grains/m³/day (95%CI: 45, 100)was the threshold at which 50% of children reported symptoms. Nasal symptoms were associated with mean daily pollen concentration over 12 days (day of symptoms plus 11 previous days); the threshold for 50% of children reporting symptoms was 40 grains/m³/day (95%CI: 24, 87). Lung symptoms showed a relationship with mean daily pollen concentration over 19 days (day of symptoms plus 18 previous days), with a threshold of 71 grains/m³/day (95%CI: 59, 88). Taking medication on the day of symptoms showed higher odds, suggesting responsive behaviour. Taking medication on the day prior to symptoms showed lower odds of reporting, indicating preventative behaviour. Different symptoms in children demonstrate varying dose-response relationships with ragweed pollen concentrations. Each symptom type responded to pollen exposure over different time periods. Using medication prior to symptoms can reduce symptom presence. These findings can be used to better manage paediatric ragweed allergy symptoms.
Article
The objective of this study was to investigate the effects of cold atmospheric plasma on the antigenicity of protein Ara h 1. Dry, defatted peanut flour (DPF), whole peanut (WP) were subjected to cold atmospheric plasma at voltage of 80 kV for different treatment durations (0, 15, 30, 45 and 60 min). The allergen samples were analyzed using SDS-PAGE, immunoblot and competitive ELISA. Furthermore, the secondary structure was examined using circular dichroism. SDS-PAGE results revealed no change in the protein intensity bands corresponding to Ara h 1 for both DPF and WP. Competitive ELISA of samples showed a reduction in antigenicity up to 43% for DPF and 9.3% for WP. Circular dichroism studies revealed modifications in secondary structure induced by plasma reactive species. Industrial relevance: Cold plasma has emerged as a novel processing technique. This study provides evidence for reduction of antigenicity of Ara h1 in peanuts using cold plasma. This study also demonstrated the plasma-induced changes in protein structure at high treatment duration. The work described in this research is relevant to the processing of cereal grains and legumes wherein allergenicity is a major concern. This results provide the basis for possible industrial implementation.
Article
Pollen allergy risk is modified by air pollutants, including ozone, but the chemical modifications induced on pollen grains are poorly understood. Pollen lipidic extract has been shown to act as an adjuvant to the allergenic reaction and therefore, the modification of lipids by air pollutants could have health implications. Birch pollen was exposed in vitro to ozone to explore the reactivity of O3 on its surface and on its lipidic fraction. Uptake coefficients of ozone were determined for ozone concentration of 117 ppb on the surface of native birch pollen (8.6 ± 0.8 × 10-6), defatted pollen (9.9 ± 0.9 × 10-6), and for crushed pollen grains (34±3 × 10-6). The mass of ozone uptaken was increased by a factor of four for crushed pollen compared to native pollen showing a higher susceptibility to ozone of cytoplasmic granules and broken pollen grains. A total mass of extractible lipids of 27 mg per gram of birch pollen was found and a fraction of these lipids was identified and quantified (fatty acids, alkanes, alkenes and aldehydes). The distribution of lipids was modified by ozone exposure of 115 and 1000 ppb for 16 h with the following reactivity: consumption of alkene, formation of aldehydes and formation of nonanoic acid and octadecanoic acid. The quantity of ozone trapped in the lipidic fraction during 15 min at 115 ppb is enough to contribute to the reactivity of one-third of the alkenes demonstrating that pollen could be susceptible to an atmospheric increase of ozone concentration even for a very short duration complicating the understanding of the link between pollen allergy and pollution.
Article
Air is obligatorily used as a supply gas in most of the plasma-aided processing (e.g., plasma-catalysis) systems because it is the most cost-effective approach, but the simultaneous production of gaseous ozone and nitrogen oxides is an unavoidable issue. Consequently, facilitating the separate production of ozone and nitrogen oxides is the primary requirement for achieving the desired plasma performance for specific purposes, yet it is poorly studied. Here, we report the chemical interplay among ozone and nitrogen oxides (i.e., NO, NO2, NO3, N2O4, N2O5) in air-based plasmas using surface dielectric barrier discharge (DBD) actuators as a reference plasma. A gas-tight chamber containing a DBD apparatus was designed for in-situ optical absorption spectroscopy to measure the concentrations of the chemicals. The temporal evolution of each chemical was successfully observed, and a rapid change in the plasma-chemistry mode (i.e., O3- to NO2-dominant mode) was clearly demonstrated. As a control parameter, the gas temperature, which ranged from 25 °C to 250 °C, was set in separate experiments. As the gas temperature was increased, ozone decomposed faster, while NO2 became a dominant chemical species in the reactor earlier. All experimental results were compared with zero-dimensional modeling results, and the interplay among ozone and nitrogen oxides in air plasma was qualitatively analyzed. The gas temperature, which can be influenced by ohmic heating of the plasma itself, convective cooling from external or internal gas flow, or external settings, should be carefully considered for future study and commercialization.
Article
Ambrosia artemisiifolia, also known as common or short ragweed, is an invasive annual flowering herbaceous plant that has its origin in North America. Nowadays, ragweed can be found in many areas worldwide. Ragweed pollen is known for its high potential to cause type I allergic reactions in late summer and autumn and represents a major health problem in America and several countries in Europe. Climate change and urbanization, as well as long distance transport capacity, enhance the spread of ragweed pollen. Therefore ragweed is becoming domestic in non-invaded areas which in turn will increase the sensitization rate. So far 11 ragweed allergens have been described and, according to IgE reactivity, Amb a 1 and Amb a 11 seem to be major allergens. Sensitization rates of the other allergens vary between 10 and 50%. Most of the allergens have already been recombinantly produced, but most of them have not been characterized regarding their allergenic activity, therefore no conclusion on the clinical relevance of all the allergens can be made, which is important and necessary for an accurate diagnosis. Pharmacotherapy is the most common treatment for ragweed pollen allergy but fails to impact on the course of allergy. Allergen-specific immunotherapy (AIT) is the only causative and disease-modifying treatment of allergy with long-lasting effects, but currently it is based on the administration of ragweed pollen extract or Amb a 1 only. In order to improve ragweed pollen AIT, new strategies are required with higher efficacy and safety.
Article
A systematic study of the high-pressure effect on the pyrolysis of solid α-amino acids L-leucine (C6H13NO2), L-alanine (C3H7NO2), L-aspartic acid (C4H7NO4) and glycine (C2H5NO2) is presented. The experiments were performed at 7.7 GPa during 1 min in the temperature range from 300 to 800 °C. The effect of the pyrolysis under high pressure on the electronic structure of carbon and nitrogen was investigated by X-ray photoelectron spectroscopy (XPS). The effect on the atomic bonding configuration was studied by infrared and Raman spectroscopy. The obtained results suggested that the thermal decomposition of amino acids under pressure at 300 and 400 °C started with dehydration followed by polymerization. For temperatures above 600 °C it was observed the formation of graphite-like structures functionalized with nitrogen and oxygen atoms.
Article
Background: This review will inform updated National Asthma Education and Prevention Program clinical practice guidelines. Objective: To evaluate the effectiveness of allergen reduction interventions on asthma outcomes. Methods: We systematically searched the gray literature and five bibliographic databases. Eligible studies included systematic reviews, randomized controlled trials, and nonrandomized interventional studies. Risk of bias was assessed using the Cochrane Risk of Bias instrument and the Newcastle-Ottawa scale. The evidence base was assessed using the approach of the Agency for Healthcare Research and Quality's Evidence-based Practice Center program. Results: Fifty-nine randomized and 8 non-randomized trials addressed 8 interventions: acaricide, air purification, carpet removal, high-efficiency particulate air-filtration (HEPA) vacuums, mattress covers, mold removal, pest control, and pet removal. Thirty-seven studies evaluated single component interventions, and 30 studies assessed multicomponent interventions. Heterogeneity precluded meta-analysis. For most interventions and outcomes, the evidence base was inconclusive or showed no effect. No interventions were associated with improvement in validated asthma control measures or pulmonary physiology. Exacerbations were diminished in multicomponent studies that included HEPA vacuums or pest control (moderate strength of evidence [SOE] for both). Quality of life improved in studies of air purifiers (low SOE), and in multicomponent studies that included HEPA vacuums (moderate SOE) or pest control (low SOE). Conclusions: Single interventions were generally not associated with improvement in asthma measures, with most strategies showing inconclusive results or no effect. Multicomponent interventions improved various outcomes, but no combination of specific interventions appears to be more effective. The evidence was often inconclusive because of a lack of studies. Further research is needed comparing the effect of indoor allergen reduction interventions on validated asthma measures, with sufficient population sizes to detect clinically meaningful differences.
Article
Carbohydrates are widespread and naturally occurring compounds, and essential constituents for living organisms. They are quite often reported when biological systems are studied and their role is discussed. However surprisingly, up till now there is no database collecting vibrational spectra of carbohydrates and their assignment, as has been done already for other biomolecules. So, this paper serves as a comprehensive review, where for selected 14 carbohydrates in the solid state both FT-Raman and ATR FT-IR spectra were collected and assigned. Carbohydrates can be divided into four chemical groups and in the same way is organized this review. First, the smallest molecules are discussed, i.e. monosaccharides (d-(−)-ribose, 2-deoxy-d-ribose, l-(−)-arabinose, d-(+)-xylose, d-(+)-glucose, d-(+)-galactose and d-(−)-fructose) and disaccharides (d-(+)-sucrose, d-(+)-maltose and d-(+)-lactose), and then more complex ones, i.e. trisaccharides (d-(+)-raffinose) and polysaccharides (amylopectin, amylose, glycogen). Both Raman and IR spectra were collected in the whole spectral range and discussed looking at the specific regions, i.e. region V (3600–3050 cm− 1), IV (3050–2800 cm− 1) and II (1200–800 cm− 1) assigned to the stretching vibrations of the OH, CH/CH2 and C-O/C-C groups, respectively, and region III (1500–1200 cm− 1) and I (800–100 cm− 1) dominated by deformational modes of the CH/CH2 and CCO groups, respectively. In spite of the fact that vibrational spectra of saccharides are significantly less specific than spectra of other biomolecules (e.g. lipids or proteins), marker bands of the studied molecules can be identified and correlated with their structure.