Gyula Oros - Academia.edu (original) (raw)

Papers by Gyula Oros

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Biomedical Chromatography, May 1, 1996

The hydrophobicity and specific hydrophilic surface area of 29 antibiotics were determined by rev... more The hydrophobicity and specific hydrophilic surface area of 29 antibiotics were determined by reversed-phase thin-layer chromatography using impregnated silica and alumina supports and methanol:water mixtures as eluents. It was found that the supports retain their original retention characteristics even after impregnation influencing the reversed-phase retention of antibiotics. It was established that the hydrophobicity parameters are intercorrelated both on impregnated silica and alumina layers, indicating that antibiotics behave as a homologous series of solutes. However, the correlations were not strong enough to substitute the parameters with each other in quantitative structure-activity relationship studies. The specific hydrophobic surface areas determined on impregnated silica and alumina showed no significant correlation, proving the decisive role of support characteristics in the determination of this parameter.

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De Gruyter eBooks, Dec 31, 1982

Calixin exhibited high activity against some phytopathogenic bacteria (Corynebacterium michiganen... more Calixin exhibited high activity against some phytopathogenic bacteria (Corynebacterium michiganense, C. fascians). In this report we try to show its possible antibacterial mode of action.

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PubMed, 1986

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Journal of Liquid Chromatography & Related Technologies, Jan 18, 2000

The interaction of 18 commercial pesticides with a water-soluble β-cyclodextrin polymer (BCDP) wa... more The interaction of 18 commercial pesticides with a water-soluble β-cyclodextrin polymer (BCDP) was determined by charge-transfer reversed phase thin layer chromatography and the relative strength of interaction was calculated. The relationship between the calculated surface parameters of pesticides and their capacity to interact with BCDP was elucidated by stepwise regression analysis. BCDP decreased the lipophilicity of the majority of pesticides probably by the formation of inclusion complexes. Significant quadratic relationships were found between the relative strength of interaction and the polar surface area and polar surface energy of pesticides emphasizing the impact of surface characteristics on the relative strength of interaction. The result suggests that the agrochemical properties (adsorption, uptake, half-life, etc.) of pesticide - BCDP complex may be different from those of uncomplexed compounds resulting in modified effectivity.

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Environment International, Nov 1, 2002

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Advances in Bioscience and Biotechnology, 2021

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Global Journal of Science Frontier Research, Jul 31, 2020

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Journal of Liquid Chromatography & Related Technologies, Aug 1, 2006

The free energy of adsorption, the surface area of adsorption on silica and alumina surfaces, and... more The free energy of adsorption, the surface area of adsorption on silica and alumina surfaces, and the molecular lipophilicity of 37 thiophosphorylglycinamide (TPGA) derivatives was determined by thin layer chromatography using silica and alumina supports and silica support impregnated with paraffin oil. The relationships between the physicochemical characteristics of analytes were elucidated by stepwise regression analysis. It was found that

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Chemometrics and Intelligent Laboratory Systems, Nov 1, 1997

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Environmental Toxicology and Chemistry, 2002

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Chemometrics and Intelligent Laboratory Systems, Mar 1, 2009

The antimicrobial effect of 7 benzimidazolium salts (base, chloride, sulfate, phosphate and nitra... more The antimicrobial effect of 7 benzimidazolium salts (base, chloride, sulfate, phosphate and nitrate forms) was determined on 15 microorganisms. The similarities and dissimilarities among the data consisting of the benzimidazolium salts and microorganisms were elucidated by using the Tucker model combined with cluster analysis. The calculations demonstrated that the combined method can be successfully employed for the separation of the impact of the molecular structure and cation type on the antimicrobial activity of the base and benzimidazolium salts.

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Journal of Separation Science, Apr 1, 2008

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Journal of inclusion phenomena, 1984

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Environment International, Sep 1, 2004

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Journal of Inclusion Phenomena and Macrocyclic Chemistry, 1994

The interaction between 19 antibiotics and hydroxypropyl-β-cyclodextrin (HPβCD) was studied by re... more The interaction between 19 antibiotics and hydroxypropyl-β-cyclodextrin (HPβCD) was studied by reversed-phase thin-layer chromatography. HPβCD formed inclusion complexes with 16 compounds, the complex always being more hydrophilic than the uncomplexed drug. The intensity of interaction significantly increased with increasing specific hydrophobic surface area of the guest molecule proving the preponderant role of hydrophobic interactions in inclusion complex formation. The intensity of the HPβCD-drug interaction significantly decreased with increasing concentration of methanol in the environment indicating that methanol can also enter the cyclodextrin cavity and inhibits competitively the inclusion complex formation or the free energy of transfer from water to the HPβCD cavity should be less negative at higher concentration of methanol in the aqueous medium.

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European Chemical Bulletin, Jul 22, 2013

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Sar and Qsar in Environmental Research, Apr 1, 2009

The antifungal activity of 14 anthracene-based synthetic dyes and 6 reference compounds was measu... more The antifungal activity of 14 anthracene-based synthetic dyes and 6 reference compounds was measured on 36 fungal strains and the data matrix was evaluated separately by principal component analysis (PCA) and using a spectral mapping technique (SPM). The dimensionality of the maps of principal component loadings and variables and the selectivity maps was reduced to two by non-linear mapping. Except for two compounds, the dyes showed marked antifungal activity. Calculations proved that both the strength and selectivity of the biological effect of anthracene-based dyes were highly dependent on the chemical structure of the dye and on the type of fungi. PCA and SPM revealed different aspects of the antifungal activity, therefore, their simultaneous application in future quantitative structure-activity relationship studies is highly recommended.

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European Chemical Bulletin, Aug 5, 2012

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Journal of Liquid Chromatography & Related Technologies, Jun 1, 2012

The lipophilicity of 6 carboxamide fungicides and 11 phenylbenzamide derivatives were determined ... more The lipophilicity of 6 carboxamide fungicides and 11 phenylbenzamide derivatives were determined by reversed phase layer chromatography (RP-TLC) employing silica and alumina as stationary phases impregnated with paraffin oil. Mixtures of methanol-water, acetonitrile-water, tetrahydrofurane-water, and acetone-water were used as mobile phases. The RM0 and b values related to the molecular lipophilicity and to the specific hydrophobic surface area (b) of the solutes were calculated separately for each RP-TLC system and for each analyte. The correlations between the physicochemical parameters measured were calculated by linear regression analysis. The impact of the site and character of the substituent on the retention of analytes was assessed by Free-Wilson analysis.The measured lipophilicity parameters were compared with 24 molecular descriptors computed applying free engines of the web. Calculations proved that the character of the stationary phase and the type of organic modifier exerted a negligible effect on the measured lipophilicity parameters. In the majority of cases the RM0 and b values and computed molecular descriptors were intercorrelated, but the fitness of the points to the linear regression equation was not strong enough to replace the measured values with the computed ones. This finding indicates the importance of using not only computed but also measured parameters for the future studies of both quantitative structure retention relationship (QSRR) and quantitative structure activity relationship (QSAR) calculations.

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Biomedical Chromatography, May 1, 1996

The hydrophobicity and specific hydrophilic surface area of 29 antibiotics were determined by rev... more The hydrophobicity and specific hydrophilic surface area of 29 antibiotics were determined by reversed-phase thin-layer chromatography using impregnated silica and alumina supports and methanol:water mixtures as eluents. It was found that the supports retain their original retention characteristics even after impregnation influencing the reversed-phase retention of antibiotics. It was established that the hydrophobicity parameters are intercorrelated both on impregnated silica and alumina layers, indicating that antibiotics behave as a homologous series of solutes. However, the correlations were not strong enough to substitute the parameters with each other in quantitative structure-activity relationship studies. The specific hydrophobic surface areas determined on impregnated silica and alumina showed no significant correlation, proving the decisive role of support characteristics in the determination of this parameter.

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De Gruyter eBooks, Dec 31, 1982

Calixin exhibited high activity against some phytopathogenic bacteria (Corynebacterium michiganen... more Calixin exhibited high activity against some phytopathogenic bacteria (Corynebacterium michiganense, C. fascians). In this report we try to show its possible antibacterial mode of action.

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PubMed, 1986

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Journal of Liquid Chromatography & Related Technologies, Jan 18, 2000

The interaction of 18 commercial pesticides with a water-soluble β-cyclodextrin polymer (BCDP) wa... more The interaction of 18 commercial pesticides with a water-soluble β-cyclodextrin polymer (BCDP) was determined by charge-transfer reversed phase thin layer chromatography and the relative strength of interaction was calculated. The relationship between the calculated surface parameters of pesticides and their capacity to interact with BCDP was elucidated by stepwise regression analysis. BCDP decreased the lipophilicity of the majority of pesticides probably by the formation of inclusion complexes. Significant quadratic relationships were found between the relative strength of interaction and the polar surface area and polar surface energy of pesticides emphasizing the impact of surface characteristics on the relative strength of interaction. The result suggests that the agrochemical properties (adsorption, uptake, half-life, etc.) of pesticide - BCDP complex may be different from those of uncomplexed compounds resulting in modified effectivity.

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Environment International, Nov 1, 2002

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Advances in Bioscience and Biotechnology, 2021

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Global Journal of Science Frontier Research, Jul 31, 2020

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Journal of Liquid Chromatography & Related Technologies, Aug 1, 2006

The free energy of adsorption, the surface area of adsorption on silica and alumina surfaces, and... more The free energy of adsorption, the surface area of adsorption on silica and alumina surfaces, and the molecular lipophilicity of 37 thiophosphorylglycinamide (TPGA) derivatives was determined by thin layer chromatography using silica and alumina supports and silica support impregnated with paraffin oil. The relationships between the physicochemical characteristics of analytes were elucidated by stepwise regression analysis. It was found that

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Chemometrics and Intelligent Laboratory Systems, Nov 1, 1997

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Environmental Toxicology and Chemistry, 2002

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Chemometrics and Intelligent Laboratory Systems, Mar 1, 2009

The antimicrobial effect of 7 benzimidazolium salts (base, chloride, sulfate, phosphate and nitra... more The antimicrobial effect of 7 benzimidazolium salts (base, chloride, sulfate, phosphate and nitrate forms) was determined on 15 microorganisms. The similarities and dissimilarities among the data consisting of the benzimidazolium salts and microorganisms were elucidated by using the Tucker model combined with cluster analysis. The calculations demonstrated that the combined method can be successfully employed for the separation of the impact of the molecular structure and cation type on the antimicrobial activity of the base and benzimidazolium salts.

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Journal of Separation Science, Apr 1, 2008

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Journal of inclusion phenomena, 1984

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Environment International, Sep 1, 2004

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Journal of Inclusion Phenomena and Macrocyclic Chemistry, 1994

The interaction between 19 antibiotics and hydroxypropyl-β-cyclodextrin (HPβCD) was studied by re... more The interaction between 19 antibiotics and hydroxypropyl-β-cyclodextrin (HPβCD) was studied by reversed-phase thin-layer chromatography. HPβCD formed inclusion complexes with 16 compounds, the complex always being more hydrophilic than the uncomplexed drug. The intensity of interaction significantly increased with increasing specific hydrophobic surface area of the guest molecule proving the preponderant role of hydrophobic interactions in inclusion complex formation. The intensity of the HPβCD-drug interaction significantly decreased with increasing concentration of methanol in the environment indicating that methanol can also enter the cyclodextrin cavity and inhibits competitively the inclusion complex formation or the free energy of transfer from water to the HPβCD cavity should be less negative at higher concentration of methanol in the aqueous medium.

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European Chemical Bulletin, Jul 22, 2013

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Sar and Qsar in Environmental Research, Apr 1, 2009

The antifungal activity of 14 anthracene-based synthetic dyes and 6 reference compounds was measu... more The antifungal activity of 14 anthracene-based synthetic dyes and 6 reference compounds was measured on 36 fungal strains and the data matrix was evaluated separately by principal component analysis (PCA) and using a spectral mapping technique (SPM). The dimensionality of the maps of principal component loadings and variables and the selectivity maps was reduced to two by non-linear mapping. Except for two compounds, the dyes showed marked antifungal activity. Calculations proved that both the strength and selectivity of the biological effect of anthracene-based dyes were highly dependent on the chemical structure of the dye and on the type of fungi. PCA and SPM revealed different aspects of the antifungal activity, therefore, their simultaneous application in future quantitative structure-activity relationship studies is highly recommended.

Bookmarks Related papers MentionsView impact

European Chemical Bulletin, Aug 5, 2012

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Journal of Liquid Chromatography & Related Technologies, Jun 1, 2012

The lipophilicity of 6 carboxamide fungicides and 11 phenylbenzamide derivatives were determined ... more The lipophilicity of 6 carboxamide fungicides and 11 phenylbenzamide derivatives were determined by reversed phase layer chromatography (RP-TLC) employing silica and alumina as stationary phases impregnated with paraffin oil. Mixtures of methanol-water, acetonitrile-water, tetrahydrofurane-water, and acetone-water were used as mobile phases. The RM0 and b values related to the molecular lipophilicity and to the specific hydrophobic surface area (b) of the solutes were calculated separately for each RP-TLC system and for each analyte. The correlations between the physicochemical parameters measured were calculated by linear regression analysis. The impact of the site and character of the substituent on the retention of analytes was assessed by Free-Wilson analysis.The measured lipophilicity parameters were compared with 24 molecular descriptors computed applying free engines of the web. Calculations proved that the character of the stationary phase and the type of organic modifier exerted a negligible effect on the measured lipophilicity parameters. In the majority of cases the RM0 and b values and computed molecular descriptors were intercorrelated, but the fitness of the points to the linear regression equation was not strong enough to replace the measured values with the computed ones. This finding indicates the importance of using not only computed but also measured parameters for the future studies of both quantitative structure retention relationship (QSRR) and quantitative structure activity relationship (QSAR) calculations.

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Prime Archives in Plant Sciences, 2020

This study aimed to examine whether Trichoderma species might have potential as a biological cont... more This study aimed to examine whether Trichoderma species might have potential as a biological control agent against another Trichoderma spp. possibly residing in the local environment. Metabolites of thirty Trichoderma isolates were screened for growth moderating activity against test fungi in dual cultures using the vertical diffusion technique. Most of the different Trichoderma isolates as producers demonstrated strain-dependent growth moderating activities either stimulating or completely inhibiting the exposed fungi, while some isolates showed no activity.
The examined Trichoderma spp. showed high natural variation in sensitivity responses to metabolites released to the medium by other Trichoderma strains, depending on traits related to their adaptation to ecological niches, thus the suspected mycoparasitic strains significantly differed of those habiting in soil. The released complex set of metabolites with broad intrageneric spectrum of growth moderating activity exhibited broad spectrum of activity against phytopathogenic fungi as well, however, the strength of the effect could not be predicted.
Few common factors were revealed by comparing growth responses of Trichoderma and phytopathogens (their possible hosts) to released metabolites by examined Trichoderma strains. Seemingly, some genus-specific traits regulate the character of intrageneric connections among various Trichoderma strains. These properties might influence the performance of Trichoderma-based eubiotic preparations in pest management practices.

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Present control technologies of plant pathogenic fungi decouple the pathogen's life cycle mainly ... more Present control technologies of plant pathogenic fungi decouple the pathogen's life cycle mainly in two points of ontogeny, either by destroying spores prevent the infection or inhibit the biotrophic thallus, thus anticipating the formation of new infective propagules. Although, nowadays, the only tool for credible control of cultivated plants is the use of synthetic chemicals, the calculability of yield sureness has been worldwide threatened by the emergence of acquired tolerance to this group of pesticides as well as anxious feelings for their undesirable side effects. This situation urges the development of efficient alternative control agents, as threatening the net return even 10% disease incidence can cause economic loss. One approach to discover newer antimicrobial compounds is to search for their presence in natural sources exploiting the defense strategies of plants against their pathogens. Contrary to phytoalexins that are synthesized de novo after the plant is exposed to microbial attack, i.e., being produced in response of elicitors or stressors, the phytoanticipins are not formed in the tissue or released from preexisting plant constituents. These substances are plant antibiotics presented in tissue prior to infection, serving as the basis of pest tolerance. Several thousands of such molecules of different structure have been identified; however, few of them met practical application. In this chapter, we focus on constitutive mechanisms that might be used for controlling phytopathogenic fungi with special regard to organic substances, which might serve either as botanical fungicides or as lead compounds for molecular design. Consequently, the introduction of alien phytoanticipins and precursors of phytoalexins into the proper host/ parasite system can represent a prospective tool for disease management. We summarized the results and experiences of past three decades searching for candidates for biofungicides useful in pest management practices. The efficacy of over 100 plant species used as either spices or preparations in traditional medicine or culinary was demonstrated in vitro against 25 phytopathogenic fungi, and possible use of promising candidates was discussed.

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7th Recent Advances in Food Analysis, 2015

The exposure of plants to ionizing radiation (IR) is known to trigger a wide range of responses b... more The exposure of plants to ionizing radiation (IR) is known to trigger a wide range of responses between initial absorption of energy and final biological injury. In this study, we performed multi-omic study to investigate the effects of gamma radiation on seeds of rice plants (cv. Koshihikari) grown in radionuclide contaminated soil at Iitate farm located in Iitate village consequent to the nuclear power plant disaster of March 2011, Fukushima prefecture. Seeds from rice plants (cv. Koshihikari) grown in clean soil served as control. The gene expression analysis was conducted using rice 4 × 44 k microarrays and metabolite analysis was done by using LC/MS and GC/MS followed by combined data analysis using GeneSpring software. Gene expression microarray analysis revealed 1891 and 440 genes as gamma ray inducible and repressible genes, respectively (P<0.05). The metabolite analysis using LC/MS and GC/MS revealed 50 differential metabolites (P<0.05). The combined multi-omics analysis revealed modulation of several metabolic and defense pathways related to stress response of plants. Interconnectivity between upstream and downstream pathways at gene and metabolite levels were also observed. Our results suggest that the rice plants grown up in radionuclide contaminated soils form seeds with elevated capability to defend well by eliciting appropriate stress responses.
Cite as: G Hayashi, J Shibato , A Kubo, M Fukumoto, S Shioda, G Oros, R Rakwal, SA Deepak (2015): Multi-Omic Approach to Reveal the Effect of Low-Level Gamma Radiation on Rice Seeds. Book of Abstracts (Editors Jana Hajšlová and Michel Nielen) of the 7th Recent Advances in Food Analysis · RAFA 2015, November 3–6, 2015, Prague, Czech Republic, Published by the University of Chemistry and Technology, Prague, p. 284. ISBN 978-80-7080-934-1

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