20 results on '"Virág, D."'
Search Results
2. Antibacterial activity of Hungarian varietal honeys against respiratory pathogens as a function of storage time
- Author
-
Lilla Nagy-Radványi, Viktória L. Balázs, Béla Kocsis, Eszter Csikós, Virág D. Ángyán, Péter Szabó, Viktória Biró, Marianna Kocsis, and Ágnes Farkas
- Subjects
Medicine ,Science - Abstract
Abstract Today, antibiotic therapies that previously worked well against certain bacteria due to their natural sensitivity, are becoming less effective. Honey has been proven to inhibit the biofilm formation of some respiratory bacteria, however few data are available on how the storage time affects the antibacterial effect. The activity of black locust, goldenrod, linden and sunflower honeys from three consecutive years (2020, 2021, 2022) was analyzed in 2022 against Gram-negative (Haemophilus influenzae, H. parainfluenzae, Pseudomonas aeruginosa) and Gram-positive (Streptococcus pneumoniae) bacteria using in vitro microbiological methods. After determining the physicochemical parameters of honey, broth microdilution was applied to determine the minimum inhibitory concentration of each honey type against each bacterium, and crystal violet assay was used to test their antibiofilm effect. The possible mechanism of action was explored with membrane degradation test, while structural changes were illustrated with scanning electron microscopy. Honeys stored for one or two years were darker than fresh honeys, while older honeys had significantly lower antibacterial activity. The most remarkable inhibitory effect was exerted by linden and sunflower honeys, and P. aeruginosa proved to be the most resistant bacterium. Based on our results, honey intended for medicinal purposes should be used as fresh as possible during a treatment.
- Published
- 2024
- Full Text
- View/download PDF
3. How much infrastructure is required to support decent mobility for all? An exploratory assessment
- Author
-
Virág, D., Wiedenhofer, D., Baumgart, A., Matej, S., Krausmann, F., Min, J., Rao, N.D., Haberl, H., Virág, D., Wiedenhofer, D., Baumgart, A., Matej, S., Krausmann, F., Min, J., Rao, N.D., and Haberl, H.
- Abstract
Decarbonizing transport is crucial for achieving climate targets, which is challenging because mobility is growing rapidly. Personal mobility is a key societal service and basic need, but currently not available to everyone with sufficient quality and quantity. The basis for mobility and accessibility of desired destinations is infrastructure, but its build-up and maintenance require a substantial fraction of global resource use. The question arises, how much mobility and how much infrastructure are required to deliver decent, sustainable mobility. We explore the relations between mobility levels, mobility infrastructure and well-being. We synthesize definitions of decent mobility and assess mobility measurements and provide a novel estimate of mobility infrastructure stocks for 172 countries in the year ~2021. We then explore the relations between infrastructure, travelled distances, accessibility, economic activity and several ‘beyond GDP’ well-being indicators. We find that travelled distances and mobility infrastructure levels are significantly correlated. Above levels of ~92–207 t/cap of mobility infrastructure no further significant gains in well-being can be expected from a further increase of infrastructure. We conclude that high mobility in terms of distances travelled as well as buildi
- Published
- 2022
4. Interpretation and modelling of environmental behaviour of diverse pesticides by revealing photodecomposition mechanisms
- Author
-
Kiss, A. and Virág, D.
- Published
- 2009
- Full Text
- View/download PDF
5. Reviewing the scope and thematic focus of 100 000 publications on energy consumption, services and social aspects of climate change: A big data approach to demand-side mitigation *
- Author
-
Creutzig, F., Callaghan, M., Ramakrishnan, A., Javaid, A., Niamir, L., Minx, J., Müller-Hansen, F., Sovacool, B., Afroz, Z., Andor, M., Antal, M., Court, V., Das, N., Díaz-José, J., Döbbe, F., Figueroa, M.J., Gouldson, A., Haberl, H., Hook, A., Ivanova, D., Lamb, W.F., Maïzi, N., Mata, É., Nielsen, K.S., Onyige, C.D., Reisch, L.A., Roy, J., Scheelbeek, P., Sethi, M., Some, S., Sorrell, S., Tessier, M., Urmee, T., Virág, D., Wan, C., Wiedenhofer, D., Wilson, C., Creutzig, F., Callaghan, M., Ramakrishnan, A., Javaid, A., Niamir, L., Minx, J., Müller-Hansen, F., Sovacool, B., Afroz, Z., Andor, M., Antal, M., Court, V., Das, N., Díaz-José, J., Döbbe, F., Figueroa, M.J., Gouldson, A., Haberl, H., Hook, A., Ivanova, D., Lamb, W.F., Maïzi, N., Mata, É., Nielsen, K.S., Onyige, C.D., Reisch, L.A., Roy, J., Scheelbeek, P., Sethi, M., Some, S., Sorrell, S., Tessier, M., Urmee, T., Virág, D., Wan, C., Wiedenhofer, D., and Wilson, C.
- Abstract
As current action remains insufficient to meet the goals of the Paris agreement let alone to stabilize the climate, there is increasing hope that solutions related to demand, services and social aspects of climate change mitigation can close the gap. However, given these topics are not investigated by a single epistemic community, the literature base underpinning the associated research continues to be undefined. Here, we aim to delineate a plausible body of literature capturing a comprehensive spectrum of demand, services and social aspects of climate change mitigation. As method we use a novel double-stacked expert—machine learning research architecture and expert evaluation to develop a typology and map key messages relevant for climate change mitigation within this body of literature. First, relying on the official key words provided to the Intergovernmental Panel on Climate Change by governments (across 17 queries), and on specific investigations of domain experts (27 queries), we identify 121 165 non-unique and 99 065 unique academic publications covering issues relevant for demand-side mitigation. Second, we identify a literature typology with four key clusters: policy, housing, mobility, and food/consumption. Third, we systematically extract key content-based insights finding that the housing literature emphasizes social and collective action, whereas the food/consumption literatures highlight behavioral change, but insights also demonstrate the dynamic relationship between behavioral change and social norms. All clusters point to the possibility of improved public health as a result of demand-side solutions. The centrality of the policy cluster suggests that political actions are what bring the different specific approaches together. Fourth, by mapping the underlying epistemic communities we find that researchers are already highly interconnected, glued together by common interests in sustainability and energy demand. We conclude by outlining avenues for in
- Published
- 2021
6. Reviewing the scope and thematic focus of 100 000 publications on energy consumption, services and social aspects of climate change: A big data approach to demand-side mitigation
- Author
-
Creutzig, F, Callaghan, M, Ramakrishnan, A, Javaid, A, Niamir, L, Minx, J, Müller-Hansen, F, Sovacool, B, Afroz, Z, Andor, M, Antal, M, Court, V, Das, N, Díaz-José, J, Döbbe, F, Figueroa, MJ, Gouldson, A, Haberl, H, Hook, A, Ivanova, D, Lamb, WF, Maïzi, N, Mata, É, Nielsen, KS, Onyige, CD, Reisch, LA, Roy, J, Scheelbeek, P, Sethi, M, Some, S, Sorrell, S, Tessier, M, Urmee, T, Virág, D, Wan, C, Wiedenhofer, D, Wilson, C, Creutzig, F, Callaghan, M, Ramakrishnan, A, Javaid, A, Niamir, L, Minx, J, Müller-Hansen, F, Sovacool, B, Afroz, Z, Andor, M, Antal, M, Court, V, Das, N, Díaz-José, J, Döbbe, F, Figueroa, MJ, Gouldson, A, Haberl, H, Hook, A, Ivanova, D, Lamb, WF, Maïzi, N, Mata, É, Nielsen, KS, Onyige, CD, Reisch, LA, Roy, J, Scheelbeek, P, Sethi, M, Some, S, Sorrell, S, Tessier, M, Urmee, T, Virág, D, Wan, C, Wiedenhofer, D, and Wilson, C
- Abstract
As current action remains insufficient to meet the goals of the Paris agreement let alone to stabilize the climate, there is increasing hope that solutions related to demand, services and social aspects of climate change mitigation can close the gap. However, given these topics are not investigated by a single epistemic community, the literature base underpinning the associated research continues to be undefined. Here, we aim to delineate a plausible body of literature capturing a comprehensive spectrum of demand, services and social aspects of climate change mitigation. As method we use a novel double-stacked expert-machine learning research architecture and expert evaluation to develop a typology and map key messages relevant for climate change mitigation within this body of literature. First, relying on the official key words provided to the Intergovernmental Panel on Climate Change by governments (across 17 queries), and on specific investigations of domain experts (27 queries), we identify 121 165 non-unique and 99 065 unique academic publications covering issues relevant for demand-side mitigation. Second, we identify a literature typology with four key clusters: policy, housing, mobility, and food/consumption. Third, we systematically extract key content-based insights finding that the housing literature emphasizes social and collective action, whereas the food/consumption literatures highlight behavioral change, but insights also demonstrate the dynamic relationship between behavioral change and social norms. All clusters point to the possibility of improved public health as a result of demand-side solutions. The centrality of the policy cluster suggests that political actions are what bring the different specific approaches together. Fourth, by mapping the underlying epistemic communities we find that researchers are already highly interconnected, glued together by common interests in sustainability and energy demand. We conclude by outlining avenues for in
- Published
- 2021
7. Study of microelement accumulating characteristics of microalgae
- Author
-
Milinki, E., primary, Molnár, Sz., additional, Kiss, A., additional, Virág, D., additional, and Pénzes-Kónya, E., additional
- Published
- 2011
- Full Text
- View/download PDF
8. A Mass Spectrometry Strategy for Protein Quantification Based on the Differential Alkylation of Cysteines Using Iodoacetamide and Acrylamide.
- Author
-
Virág D, Schlosser G, Borbély A, Gellén G, Papp D, Kaleta Z, Dalmadi-Kiss B, Antal I, and Ludányi K
- Subjects
- Alkylation, Humans, Mass Spectrometry methods, Isotope Labeling methods, Peptides chemistry, Peptides analysis, Tandem Mass Spectrometry methods, Iodoacetamide chemistry, Cysteine chemistry, Cysteine analysis, Acrylamide chemistry, Acrylamide analysis, Proteomics methods
- Abstract
Mass spectrometry has become the most prominent yet evolving technology in quantitative proteomics. Today, a number of label-free and label-based approaches are available for the relative and absolute quantification of proteins and peptides. However, the label-based methods rely solely on the employment of stable isotopes, which are expensive and often limited in availability. Here we propose a label-based quantification strategy, where the mass difference is identified by the differential alkylation of cysteines using iodoacetamide and acrylamide. The alkylation reactions were performed under identical experimental conditions; therefore, the method can be easily integrated into standard proteomic workflows. Using high-resolution mass spectrometry, the feasibility of this approach was assessed with a set of tryptic peptides of human serum albumin. Several critical questions, such as the efficiency of labeling and the effect of the differential alkylation on the peptide retention and fragmentation, were addressed. The concentration of the quality control samples calculated against the calibration curves were within the ±20% acceptance range. It was also demonstrated that heavy labeled peptides exhibit a similar extraction recovery and matrix effect to light ones. Consequently, the approach presented here may be a viable and cost-effective alternative of stable isotope labeling strategies for the quantification of cysteine-containing proteins.
- Published
- 2024
- Full Text
- View/download PDF
9. Unveiling patterns in human dominated landscapes through mapping the mass of US built structures.
- Author
-
Frantz D, Schug F, Wiedenhofer D, Baumgart A, Virág D, Cooper S, Gómez-Medina C, Lehmann F, Udelhoven T, van der Linden S, Hostert P, and Haberl H
- Subjects
- Humans, Biomass, Construction Materials, Plants
- Abstract
Built structures increasingly dominate the Earth's landscapes; their surging mass is currently overtaking global biomass. We here assess built structures in the conterminous US by quantifying the mass of 14 stock-building materials in eight building types and nine types of mobility infrastructures. Our high-resolution maps reveal that built structures have become 2.6 times heavier than all plant biomass across the country and that most inhabited areas are mass-dominated by buildings or infrastructure. We analyze determinants of the material intensity and show that densely built settlements have substantially lower per-capita material stocks, while highest intensities are found in sparsely populated regions due to ubiquitous infrastructures. Out-migration aggravates already high intensities in rural areas as people leave while built structures remain - highlighting that quantifying the distribution of built-up mass at high resolution is an essential contribution to understanding the biophysical basis of societies, and to inform strategies to design more resource-efficient settlements and a sustainable circular economy., (© 2023. The Author(s).)
- Published
- 2023
- Full Text
- View/download PDF
10. High-resolution data and maps of material stock, population, and employment in Austria from 1985 to 2018.
- Author
-
Schug F, Wiedenhofer D, Haberl H, Frantz D, Virág D, van der Linden S, and Hostert P
- Abstract
High-resolution maps of material stocks in buildings and infrastructures are of key importance for studies of societal resource use (social metabolism, circular economy, secondary resource potentials) as well as for transport studies and land system science. So far, such maps were only available for specific years but not in time series. Even for single years, data covering entire countries with high resolution, or using remote-sensing data are rare. Instead, they often have local extent (e.g., [1]), are lower resolution (e.g., [2]), or are based on other geospatial data (e.g., [3]). We here present data on the material stocks in three types of buildings (commercial and industrial, single- and multifamily houses) and three types of infrastructures (roads, railways, other infrastructures) for a 33-year time series for Austria at a spatial resolution of 30 m. The article also presents data on population and employment in Austria for the same time period, at the same spatial resolution. Data were derived with the same method applied in a recent study for Germany [4]., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Author(s).)
- Published
- 2023
- Full Text
- View/download PDF
11. Citalopram Neuroendocrine Challenge Shows Altered Tryptophan and Kynurenine Metabolism in Migraine.
- Author
-
Gecse K, Édes AE, Nagy T, Demeter AK, Virág D, Király M, Dalmadi Kiss B, Ludányi K, Környei Z, Denes A, Bagdy G, and Juhasz G
- Subjects
- Citalopram pharmacology, Citalopram therapeutic use, Double-Blind Method, Female, Humans, Kynurenine metabolism, Serotonin, Migraine Disorders drug therapy, Tryptophan metabolism
- Abstract
Altered tryptophan (TRP) metabolism may have an important role in migraine susceptibility through its main metabolites, serotonin and kynurenine (KYN). Both affect pain processing and stress response by interfering with neural and brain hypersensitivity and by interacting with chemokines and cytokines that control vascular and inflammatory processes. The involvement of these pathways in migraine has been widely studied, but acute citalopram neuroendocrine challenge on TRP metabolism and cytokine profile has not been investigated yet. In our study, females with episodic migraine without aura and healthy controls were studied before and after acute citalopram or placebo in a double-blind setting. At baseline, increased TRP/large neutral amino acid (LNAA) ratio and decreased RANTES chemokine concentration were detected in migraine patients compared to controls. The challenge induced a significant increase in TRP, KYN, and TRP/LNAA in healthy controls, but not in migraine patients. Furthermore, migraine attack frequency negatively correlated with KYN/TRP ratio and positively correlated with the neuroendocrine-challenge-induced KYN concentration increase. Our results support a decreased breakdown of TRP via KYN pathway and a failure to modulate TRP-KYN pathway during citalopram-induced acute stress together with an increased vascular sensitivity in migraine. These mechanisms may provide useful drug targets for future drug development.
- Published
- 2022
- Full Text
- View/download PDF
12. Compilation of an economy-wide material flow database for 14 stock-building materials in 177 countries from 1900 to 2016.
- Author
-
Plank B, Streeck J, Virág D, Krausmann F, Haberl H, and Wiedenhofer D
- Abstract
International datasets on economy-wide material flows currently fail to comprehensively cover the quantitatively most important materials and countries, to provide centennial coverage and to differentiate between processing stages. These data gaps hamper research and policy on resource use. Herein, we present and document the data processing and compilation procedures applied to develop a novel economy-wide database of primary stock-building material flows systematically covering 177 countries from 1900- 2016. The main methodological novelty is the consistent integration of material flow accounting and analysis principles and thereby addresses limitations in terms of transparency, data quality and uncertainty treatment. The database systematically discerns four processing stages from raw materials extraction, to processing of raw and semi-finished products, to manufacturing of stock-building materials. Included materials are concrete, asphalt, bricks, timber products, paper, iron & steel, aluminium, copper, lead, zinc, other metals, plastics, container and flat glass. The database is compiled using international and national data sources, using a transparent and consistent 10-step procedure, as well as a systematic uncertainty assessment. Apart from a detailed documentation of the data compilation, validations of the database using data from previous studies and additional uncertainty estimates are presented. • Systematically compiled historical database of primary stock-building material flows for 177 countries. • Consistent integration of economy-wide material flow accounting and detailed material flow analysis principles. • Methodological enhancements in terms of transparency, data quality and uncertainty treatment., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2022 The Author(s).)
- Published
- 2022
- Full Text
- View/download PDF
13. Association of plasma tryptophan concentration with periaqueductal gray matter functional connectivity in migraine patients.
- Author
-
Gecse K, Dobos D, Aranyi CS, Galambos A, Baksa D, Kocsel N, Szabó E, Pap D, Virág D, Ludányi K, Kökönyei G, Emri M, Bagdy G, and Juhasz G
- Subjects
- Anxiety, Case-Control Studies, Depression, Emotions, Female, Humans, Magnetic Resonance Imaging, Male, Migraine Disorders psychology, Pain Perception, Periaqueductal Gray diagnostic imaging, Tryptophan physiology, Migraine Disorders blood, Migraine Disorders physiopathology, Periaqueductal Gray physiopathology, Synaptic Transmission, Tryptophan blood
- Abstract
Altered periaqueductal gray matter (PAG) functional connectivity contributes to brain hyperexcitability in migraine. Although tryptophan modulates neurotransmission in PAG projections through its metabolic pathways, the effect of plasma tryptophan on PAG functional connectivity (PAG-FC) in migraine has not been investigated yet. In this study, using a matched case-control design PAG-FC was measured during a resting-state functional magnetic resonance imaging session in migraine without aura patients (n = 27) and healthy controls (n = 27), and its relationship with plasma tryptophan concentration (TRP) was assessed. In addition, correlations of PAG-FC with age at migraine onset, migraine frequency, trait-anxiety and depressive symptoms were tested and the effect of TRP on these correlations was explored. Our results demonstrated that migraineurs had higher TRP compared to controls. In addition, altered PAG-FC in regions responsible for fear-cascade and pain modulation correlated with TRP only in migraineurs. There was no significant correlation in controls. It suggests increased sensitivity to TRP in migraine patients compared to controls. Trait-anxiety and depressive symptoms correlated with PAG-FC in migraine patients, and these correlations were modulated by TRP in regions responsible for emotional aspects of pain processing, but TRP did not interfere with processes that contribute to migraine attack generation or attack frequency., (© 2022. The Author(s).)
- Published
- 2022
- Full Text
- View/download PDF
14. Altered Glycosylation of Human Alpha-1-Acid Glycoprotein as a Biomarker for Malignant Melanoma.
- Author
-
Virág D, Kremmer T, Lőrincz K, Kiss N, Jobbágy A, Bozsányi S, Gulyás L, Wikonkál N, Schlosser G, Borbély A, Huba Z, Dalmadi Kiss B, Antal I, and Ludányi K
- Subjects
- Biomarkers, Tumor blood, Chromatography methods, Glycosylation, Humans, Polysaccharides blood, Tandem Mass Spectrometry methods, ortho-Aminobenzoates chemistry, Melanoma blood, Orosomucoid metabolism
- Abstract
A high-resolution HILIC-MS/MS method was developed to analyze anthranilic acid derivatives of N -glycans released from human serum alpha-1-acid glycoprotein (AGP). The method was applied to samples obtained from 18 patients suffering from high-risk malignant melanoma as well as 19 healthy individuals. It enabled the identification of 102 glycan isomers separating isomers that differ only in sialic acid linkage (α-2,3, α-2,6) or in fucose positions (core, antenna). Comparative assessment of the samples revealed that upregulation of certain fucosylated glycans and downregulation of their nonfucosylated counterparts occurred in cancer patients. An increased ratio of isomers with more α-2,6-linked sialic acids was also observed. Linear discriminant analysis (LDA) combining 10 variables with the highest discriminatory power was employed to categorize the samples based on their glycosylation pattern. The performance of the method was tested by cross-validation, resulting in an overall classification success rate of 96.7%. The approach presented here is significantly superior to serological marker S100B protein in terms of sensitivity and negative predictive power in the population studied. Therefore, it may effectively support the diagnosis of malignant melanoma as a biomarker.
- Published
- 2021
- Full Text
- View/download PDF
15. High-Resolution Maps of Material Stocks in Buildings and Infrastructures in Austria and Germany.
- Author
-
Haberl H, Wiedenhofer D, Schug F, Frantz D, Virág D, Plutzar C, Gruhler K, Lederer J, Schiller G, Fishman T, Lanau M, Gattringer A, Kemper T, Liu G, Tanikawa H, van der Linden S, and Hostert P
- Subjects
- Austria, Germany
- Abstract
The dynamics of societal material stocks such as buildings and infrastructures and their spatial patterns drive surging resource use and emissions. Two main types of data are currently used to map stocks, night-time lights (NTL) from Earth-observing (EO) satellites and cadastral information. We present an alternative approach for broad-scale material stock mapping based on freely available high-resolution EO imagery and OpenStreetMap data. Maps of built-up surface area, building height, and building types were derived from optical Sentinel-2 and radar Sentinel-1 satellite data to map patterns of material stocks for Austria and Germany. Using material intensity factors, we calculated the mass of different types of buildings and infrastructures, distinguishing eight types of materials, at 10 m spatial resolution. The total mass of buildings and infrastructures in 2018 amounted to ∼5 Gt in Austria and ∼38 Gt in Germany (AT: ∼540 t/cap, DE: ∼450 t/cap). Cross-checks with independent data sources at various scales suggested that the method may yield more complete results than other data sources but could not rule out possible overestimations. The method yields thematic differentiations not possible with NTL, avoids the use of costly cadastral data, and is suitable for mapping larger areas and tracing trends over time.
- Published
- 2021
- Full Text
- View/download PDF
16. Development, validation and application of LC-MS/MS method for quantification of amino acids, kynurenine and serotonin in human plasma.
- Author
-
Virág D, Király M, Drahos L, Édes AE, Gecse K, Bagdy G, Juhász G, Antal I, Klebovich I, Dalmadi Kiss B, and Ludányi K
- Subjects
- Amino Acids metabolism, Biosensing Techniques, Calibration, Chromatography, High Pressure Liquid, Humans, Kynurenine analysis, Limit of Detection, Linear Models, Reproducibility of Results, Sensitivity and Specificity, Solvents chemistry, Spectrometry, Mass, Electrospray Ionization, Tryptophan metabolism, Amino Acids blood, Serotonin blood, Tandem Mass Spectrometry methods
- Abstract
Altered serotonergic neurotransmission is a key factor in several neurologic and psychiatric disorders such as migraine. Human and animal studies suggest that chronically low interictal serotonin levels of plasma and brain may facilitate increased activity of the trigeminovascular pathway, and may contribute to development of repeated migraine attacks. However, brain serotonin synthesis is affected by the concentration of tryptophan, its metabolites and a number of amino acids. In this work a simple and robust LC-MS/MS method for the quantitative determination of valine, leucine, isoleucine, phenylalanine, tyrosine, tryptophan, serotonin and kynurenine in human plasma has been developed and validated. Sample preparation was achieved by protein precipitation, using trifluoroacetic acid. Chromatographic separation was carried out on a Supelco Ascentis® Express C18 column (3.0 mm i.d. × 150 mm, 2.7 μm) equipped with an Agilent Zorbax Eclipse XDB C8 guard-column under isocratic conditions at a flow rate of 0.4 mL/min, over a 6.5 min run time. Mobile phase was 0.2% trifluoroacetic acid - acetonitrile (85:15, v/v). The eight analytes and two internal standards were ionized by positive electrospray ionization and detected in multiple reaction monitoring mode. A "fit-for-purpose" validation approach was adopted using surrogate matrix for the preparation of calibration samples. The calibration curves of all analytes showed excellent linearities with a correlation coefficient (r
2 ) of 0.998 or better. Spiked surrogate matrix samples and pooled human plasma were used as quality control samples. Intra-day and inter-day precisions were less than 11.8% and 14.3%, and accuracies were within the ranges of 87.4-114.3% and 87.7-113.3%, respectively. Stability of the components in standard solutions, surrogate matrix, pooled plasma and processed samples were found to be acceptable under all relevant conditions. No significant carryover effect was observed. The surrogate matrix behaved parallel to human plasma when assessed by standard addition method and diluting the authentic matrix with surrogate matrix. The method was successfully applied for analysis of 800 human plasma samples to support a clinical study., Competing Interests: Declaration of Competing Interest Authors declare no conflict of interest., (Copyright © 2019 The Authors. Published by Elsevier B.V. All rights reserved.)- Published
- 2020
- Full Text
- View/download PDF
17. Putrescine biosensor based on putrescine oxidase from Kocuria rosea.
- Author
-
Bóka B, Adányi N, Szamos J, Virág D, and Kiss A
- Subjects
- Carbon, Culture Media, Electrodes, Micrococcus classification, Micrococcus growth & development, Oxidoreductases Acting on CH-NH Group Donors metabolism, Putrescine analysis, Quality Control, Beer analysis, Biosensing Techniques methods, Biotechnology methods, Micrococcus enzymology, Oxidoreductases Acting on CH-NH Group Donors isolation & purification, Putrescine metabolism
- Abstract
The novel putrescine oxidase based amperometric biosensor selectively measures putrescine, which can be considered as an indicator of microbial spoilage. Putrescine oxidase (PUOX, EC 1.4.3.10) was isolated from Kocuria rosea (Micrococcus rubens) by an improved and simplified purification process. Cells were grown on brain heart infusion medium supplemented with putrescine. Cell-free extract was prepared in Tris buffer (pH 8.0) by Bead-beater. A newly elaborated step based on three-phase partitioning (TPP) was applied in the purification protocol of PUOX. The purified enzyme was immobilized on the surface of a spectroscopic graphite electrode in redox hydrogel with horseradish peroxidase, Os mediator and poly(ethylene glycol) (400) diglycidyl ether (PEGDGE) as crosslinking agent. This modified working electrode was used in wall-jet type amperometric cell together with the Ag/AgCl (0.1M KCl) reference electrode and a platinum wire as auxiliary electrode in flow injection analysis system (FIA). Hydrogel composition, pH and potential dependence were studied. Optimal working conditions were 0.45 mLmin(-1) flow rate of phosphate buffer (66 mM, pH 8.0) and +50 mV polarizing potential vs. Ag/AgCl. The linear measuring range of the method was 0.01-0.25 mM putrescine, while the detection limit was 5 μM. Beer samples were investigated by the putrescine biosensor and the results were compared by those of HPLC reference method., (Copyright © 2012 Elsevier Inc. All rights reserved.)
- Published
- 2012
- Full Text
- View/download PDF
18. Photostability and photodegradation pathways of distinctive pesticides.
- Author
-
Kiss A and Virág D
- Subjects
- Benzimidazoles chemistry, Carbamates chemistry, Chlorpyrifos chemistry, Gas Chromatography-Mass Spectrometry, Molecular Structure, Simazine chemistry, Toluidines chemistry, Pesticides chemistry, Photolysis
- Abstract
Transformation of pesticides in the environment is a highly complex process affected by different factors. Biological and physical-chemical factors may play a role in the degradation to variable extent. Photodecomposition might be regarded as one of the most crucial factors affecting the fate of pesticides. Therefore, our study focused on revealing specific details of the photolytic degradation of pesticides. The toxicity of the examined pesticides is well known; however, little information is available regarding their natural degradation processes. More detailed examinations are required to reveal the exact mechanism of the pesticide decomposition and the biological impacts of the degradates. Significance of this study is enhanced by the fact that decomposition of pesticides may result in the formation of toxic degradation products. The photolytic degradation of frequently applied pesticides (e.g., acetochlor, simazine, chlorpyrifos, and carbendazim) with different chemical structures was investigated. An immersible ultraviolet light source was applied to induce photodegradation. The degradation processes were followed by thin-layer chromatography and gas chromatography/mass spectrometry techniques. Electron ionization mass spectrometry was used to identify the degradation species. Detailed mechanisms of photolytic transformation were established by identification of each degradate. The photolytic degradation of pesticides of distinctive chemical character exhibited markedly different photodecomposition mechanisms. At least four degradation species were detected and identified in each case. Loss of alkyl, chloro, and hydroxyl groups as well as cleavage of alkyloxy, amide, amino-alkyl, and ester bonds might be regarded as typical decomposition patterns. Deamination and ring opening might be observed at the last stages of decomposition.
- Published
- 2009
- Full Text
- View/download PDF
19. Comparative study of accessibility of distinctive pesticides.
- Author
-
Virág D and Kiss A
- Subjects
- Adsorption, Biological Availability, Pesticides chemistry, Reproducibility of Results, Sensitivity and Specificity, Soil Pollutants chemistry, Solvents chemistry, Chromatography, High Pressure Liquid methods, Environmental Monitoring methods, Gas Chromatography-Mass Spectrometry methods, Pesticides analysis, Soil Pollutants analysis
- Abstract
Interactions of micro-contaminants with soil may play a crucial role in their environmental fate and possible harmful effects. Major goals of our investigations were to model the availability of widely used pesticides and characterize adsorption capabilities of distinctive soil types by the accomplishment of extensive comparative studies and application of several extraction methods. Environmental and biological relevance of these examinations is enhanced by the fact that intrinsic features and specific details of pesticide accessibility have not been revealed so far by a comparative approach. Five different experimental methods were assessed for modelling accessibility of five selected pesticides. The applied models for regaining the pesticides showed diverse efficiency in extraction capability in cases of the different soil types (sandy, brown forest and alluvial soils). The amounts of the obtained pesticides were determined by using gas-chromatography coupled to mass spectrometry (GC-MS) and high pressure liquid chromatography coupled to mass spectrometry (HPLC-MS). Accessibility of pesticides was also compared in cases of sterilized and real soil samples in order to estimate the extent of the influence of microflora. Aqueous extraction solvents proved to be suitable for accurate assessment of the accessible amounts of pesticides, as their effectivity was at least as high as that of the applied organic solvents. In our studies pesticide-soil interactions have comprehensively been characterized, and possible influences of environmental factors on the accessibility have also been revealed. Our study might be regarded as a tentative approach to model some significant circumstances playing key roles in pesticides' possible bioavailability.
- Published
- 2009
- Full Text
- View/download PDF
20. Microbial toxicity of pesticide derivatives produced with UV-photodegradation.
- Author
-
Virág D, Naár Z, and Kiss A
- Subjects
- Bacteria growth & development, Benzimidazoles radiation effects, Benzimidazoles toxicity, Carbamates radiation effects, Carbamates toxicity, Chlorpyrifos radiation effects, Chlorpyrifos toxicity, Fungi growth & development, Simazine radiation effects, Simazine toxicity, Soil Microbiology, Soil Pollutants radiation effects, Soil Pollutants toxicity, Thiocarbamates radiation effects, Thiocarbamates toxicity, Toluidines radiation effects, Toluidines toxicity, Anti-Infective Agents radiation effects, Anti-Infective Agents toxicity, Bacteria drug effects, Fungi drug effects, Pesticides radiation effects, Pesticides toxicity, Ultraviolet Rays
- Abstract
Our study aimed at acquiring information about the biological effect of pesticides and their degradates produced by UV-treatment on microbiological activity. Five photosensitive pesticides (carbendazim, acetochlor, simazine, chlorpyrifos, EPTC) and six representative soil microbes (Bacillus subtilis, Pseudomonas fluorescens, Mycobacterium phlei, Fusarium oxysporum, Penicillium expansum, Trichoderma harzianum) were applied throughout our model experiments. The antimicrobial effects of the pesticides and their degradates were assessed with filter paper disk method. The antimicrobial effect of the degradation products exhibited marked differences in terms of pesticide types, irradiation time, and the test organisms. Acetochlor and its photolytic degradation products were found to be more toxic to bacteria than fungi. All the three bacteria proved to be sensitive to the basic compound and its degradation products as well. The end product of carbendazim was weakly antibacterial against P. fluorescens and B. subtilis but strongly antifungal against T. harzianum. Chlorpyrifos and its end product inhibited neither test organisms, but the degradates hindered the growth of four of them. The basic compound of EPTC and the degradates of simazine exhibited significant toxicity to the test bacteria. It might be claimed that the pesticide photodegradation may result in significant changes in soil microbiota, as well as formation of biologically harmful degradates.
- Published
- 2007
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.