Redox properties of free amino acids and indole as a model compound in the fenton system

U ovoj tezi ispitivane su antioksidativne aktivnosti (AA) slobodnih aminokiselina (glicin, alanin, prolin, valin, izoleucin, leucin, fenilalanin, triptofan, tirozin, serin, treonin, asparagin, glutamin, histidin, asparaginska kiselina, glutaminska kiselina, lizin, arginin, cistein i metionin, homocistein, hidroksiprolin, norleucin, 2-aminobutanska kiselina i 3,4-dihidroksifenilalanin) u Fentonovom sistemu. Redosled reaktivnosti aminokiselina u reakciji sa hidroksil-radikalom, antioksidativne aktivnosti (HO•) bio je sledeći: Trp > norleucin > Phe, Leu > Ile > His >3,4-dihidroksifenilalanin, Arg > Val > Lys, Tyr, Pro > hidroksiprolin > α-aminobutanska kiselina > Gln, Thr, Ser > Glu, Ala, Gly, Asn, Asp. Aminokiseline koje sadrže sumpor su u reakciji sa hidroksil-radikalom davale više različitih radikalskih vrsta koje su ispitivane EPR metodom sa spinskim hvatačima...In this thesis antioxidative activities (AA) of free L-amino acids (glycine, alanine, proline, valine, isoleucine, leucine, phenylalanine, tryptophane, tyrosine, serine, threonine, asparagine, glutamine, histidine, aspartic acid, glutamic acid, lysine, arginine, cystein and methionine, homocysteine, hydroxyproline, norleucine, α-aminobutyric acid and 3,4-dihydroxyphenylalanine) against Fenton system-mediated hydroxyl radical (HO•) production in aqueous solution were studied. The rank order according to AA was: Trp > norleucine > Phe, Leu > Ile > His >3,4-dihydroxyphenylalanine, Arg > Val > Lys, Tyr, Pro > hydroxyproline> α-aminobutyric acid > Gln, Thr, Ser > Glu, Ala, Gly, Asn, Asp. Sulfur-containing FAA generated different secondary reactive products, which were discriminated by the means of electron paramagnetic resonance spin-trapping spectroscopy..

Spójność Unii Europejskiej i krajów Bałkanów Zachodnich w kontekście zrównoważonego rozwoju podróży i turystyki

Managing the future policy and strategy of tourism development is becoming increasingly challenging due to the constantly changing environment. It is crucial to identify key dimensions and implement the concept of sustainable development to ensure tourism development is sustainable. This paper aims to research the dimensions of sustainable tourism development in European Union countries and the Western Balkans. The goal is to analyze the homogeneity of these countries in terms of sustainability of tourism and travel. Additionally, this paper aims to determine the level of deviation of the Western Balkans from the European Union countries in terms of economic, ecological, and social sustainability of tourism development. Identifying critical components of tourism sustainability in these countries is important for creating strategic guidelines to manage tourism and directing supply and demand in the dynamic tourism market.Zarządzanie przyszłą polityką i strategią rozwoju turystyki staje się coraz większym wyzwaniem ze względu na stale zmieniające się otoczenie. Istotne jest zidentyfikowanie kluczowych wymiarów i wdrożenie koncepcji zrównoważonego rozwoju, aby zapewnić zrównoważony rozwój turystyki. Celem artykułu jest zbadanie wymiarów rozwoju zrównoważonej turystyki w krajach Unii Europejskiej i Bałkanach Zachodnich. Celem jest analiza spójności tych krajów pod względem zrównoważoności rozwoju turystyki i podróży. Celem artykułu jest także określenie poziomu odstawania Bałkanów Zachodnich od krajów Unii Europejskiej pod względem zrównoważenia gospodarczego, ekologicznego i społecznego rozwoju turystyki. Identyfikacja kluczowych elementów zrównoważonego rozwoju turystyki w tych krajach jest ważna dla stworzenia strategicznych wytycznych do zarządzania turystyką oraz kierowania podażą i popytem na dynamicznym rynku turystycznym

Antioxidative response in variegated Pelargonium zonale leaves and generation of extracellular H2O2 in (peri)vascular tissue induced by sunlight and paraquat

In this study we exposed variegated leaves of Pelargonium zonale to strong sunlight ( gt 1100 mu mol m(-2) s(-1) of photosynthetically active radiation) with and without paraquat (Pq), with the aim to elucidate the mechanisms of H2O2 regulation in green and white tissues with respect to the photosynthetically-dependent generation of reactive oxygen species (ROS). Sunlight induced marked accumulation of H2O2 in the apoplast of vascular and (peri)vascular tissues only in green sectors. This effect was enhanced by the addition of Pq. In the presence of diphenyl iodide, an NADPH oxidase inhibitor, H2O2 accumulation was abolished. Distinct light-induced responses were observed: in photosynthetic cells, sunlight rapidly provoked ascorbate (Asc) biosynthesis and an increase of glutathione reductase (GR) and catalase activities, while in non-photosynthetic cells, early up-regulation of soluble ascorbate peroxidase, dehydroascorbate reductase (DHAR) and GR activities was observed. Paraquat addition stimulated DHAR and GR activities in green sectors, while in white sectors activities of monodehydroascorbate reductase, DHAR and class III peroxidases, as well as Asc content rapidly increased. Differential antioxidative responses in the two tissues in the frame of their contrasting metabolisms, and the possible role of (peri)vascular H2O2 in signaling were discussed.This is the peer reviewed version of the paper: Vidović, M., Morina, F., Prokić, L., Milić-Komić, S., Živanović, B., & Jovanović, S. V. (2016). Antioxidative response in variegated Pelargonium zonale leaves and generation of extracellular H2O2 in (peri)vascular tissue induced by sunlight and paraquat. Journal of Plant Physiology, 206, 25–39. [https://doi.org/10.1016/j.jplph.2016.07.017

Fe3O4 nanoparticles as additives for gamma-ray shielding: Structural and surface characterization

Monodisperse samples of magnetite nanoparticles in the size range of 5-13nm, were prepared by solvothermal synthesis and coprecipitation method. Obtained nanoparticles were characterized by different measurement techniques: X-ray diffraction analysis, transmission electron microscopy, selected area electron diffraction measurement, and Fourier transform infra-red spectroscopy. Measurements confirmed that the utilized synthesis methods are able to produce size and shape-controlled nanoparticles of a high-quality, that is of the technological importance. The results of the performed study represent the first stage in preparation of the Fe3O4 nanoparticles as an additive to concrete, which will be used for the construction of the special military facilities where it is necessary to provide a protection against γ-ray radiation

Contents of phenolics and carotenoids in tomato grown under polytunnels with different UV-transmission rates

Tomato (Solanum lycopersicum L.) is among the economically most important vegetables in Europe, valued for its bioactive properties due to significant contents of vitamins, carotenoids, and phenolic compounds. In this study, the tomato cultivar Big Beef F1 was grown in the open field (OF) and under polytunnels in central Serbia during 3 years. Polytunnels were covered with two foils (both with 57% reduced photosynthetic active radiation, PAR) differing in UV-A and UV-B transmittance. The aim of our work was to determine the influence of light conditions on accumulation of phytonutrients (carotenoids and phenolics) in the peel and flesh of ripe tomato fruits. The amount of effective antioxidants, caffeic acid, and quercetin (phenolics with ortho-dihydroxy substitution) in the peel was the highest in tomato fruits grown in the OF (maximal PAR and UV-A and UV-B radiation). Moreover, the content of leaf epidermal flavonoids was the highest in the OF. The content of lycopene and beta-carotene in the flesh of tomato fruit was higher under the polytunnel with higher UV-transmittance. Our results showed that selection of the right light conditions (quality and intensity) for tomato production has a significant effect on the accumulation of beneficial phenolics and carotenoids

Late embryogenesis abundant proteins: Structural characterisation and interaction with α-synuclein

Ressurection plants are extraordinary because of their ability to withstand long periods without water, enter a state of anhydrobiosis, and fully recover upon water arrival. Ramonda serbica is a relic and endemic species that belong to a very small group of desiccation-tolerant plants in Europe. Underlying physiological, molecular and morphological mechanisms that enable these plants to survive harsh environmental conditions have been an appealing subject to many researchers. Most of the genes responsible for this amazing ability are present in other plants, and this path of research where those genes could be activated in crops is growing much more attention because of the imminent crisis regarding food supplies in the near future. Key components involved in the response to dehydration in R. serbica plants were analysed through a comprehensive transcriptomic, proteomic, metabolite and photosynthetic study. Late embryogenesis abundant proteins play a significant role in the complex defence processes involved in desiccation tolerance. Defining physicochemical characteristics and specific physiological functions of late embryogenesis abundant proteins – LEAPs may lead to their applicability in other areas of research

Structural characterisation of late embryogenesis abundant proteins in Ramonda serbica Panč.

Ressurection plants are extraordinary because of their ability to withstand long periods without water, enter a state of anhydrobiosis, and fully recover upon water arrival. Ramonda serbica Panč. is a relic and endemic species that belongs to a very small group of desiccation-tolerant plants in Europe. Underlying physiological, molecular and morphological mechanisms that enable these plants to survive harsh environmental conditions have been an appealing subject of many researchers. Most of the genes responsible for this amazing ability are present in other plants, and research of those genes which could be activated in crops is growing much more attention because of the imminent crisis regarding food supplies in the near future. Key components involved in the response to dehydration in R. serbica plants were analysed through a comprehensive transcriptomic, proteomic, metabolite and photosynthetic study. Late embryogenesis abundant proteins play a significant role in the complex defence processes involved in desiccation tolerance. Defining LEAPs physicochemical characteristics and specific physiological functions may lead us to their applicability in other areas of research

Hydroxyl radical generation and carbon centre depletion in the root cell wall isolate enriched with copper

Copper is often accumulated in contaminated soils such as open cast mines, and is toxic to plants. Effect of excess Cu (20 μM) on free radicals generation in the cell wall was investigated in the root cell wall isolated from Verbascum thapsus L. plants. Electron paramagnetic resonance (EPR) spectroscopy of cell wall isolates containing the spin-trapping reagent, 5-diethoxyphosphoryl-5-methyl-1-pyrroline- N-oxide (DEPMPO), was used for detection and differentiation between free radicals. EPR analysis showed an increase of DEPMPO/OH adduct concentration induced by Cu accompanied by the decrease of concentration of carbon center (DEPMPO/CH3) adduct originally determined in the cell wall of control plants. This reaction was suppressed by boiling the cell wall with SDS to denaturate proteins. We show that Cu induced •OH accumulation in the cell wall is enzyme dependent

Hydroxyl radical scavenging potential of the late embryogenesis abundant proteins (LEA) proteins from Ramonda serbica – in silico approach

Ramonda serbica Panc. is a resurrection plant that can survive long desiccation periods (extreme loss of cellular water). The accumulation of late embryogenesis abundant proteins (LEAPs) is a crucial step in desiccation tolerance mechanism. Based on in vitro studies, LEAPs can be involved in antioxidative defense, ion sequestration, structural stabilization of both membranes and enzymes during freezing or drying, while by forming intracellular proteinaceous condensates they increase structural integrity and intracellular viscosity of cells during desiccation. Here we investigated the antioxidative potential of LEAPs identified by de novo transcriptomics of R. serbica, based on their primary and secondary confirmation. In our previous work [1], we displayed the antioxidative capacity of 20 free proteogenic amino acids (FAA) through determining their hydroxyl radical (•OH, generated in Fenton reaction) scavenging rate by using electron paramagnetic resonance. These results served as a basis for generating a model for prediction of •OH scavenging activity for selected proteins. In addition, the model was built based on protein primary sequences, hydrophobicity, 3D structure and predicted solvent accessible area. Manually curated data for peptides and proteins with experimentally determined •OH scavenging rate were used for training and testing. The model was fed into machine learning algorithm and •OH scavenging potential scale was created using IC50 values. By applying our model, we classified 164 LEAPs according to their potential for •OH scavenging. Further work will focus on the experimental evaluation of the obtained model by measuring of the rate of • OH scavenging in the presence of recombinantly produced LEAPs.Organized by Society for Free Radical Research Europe (SFRR-E)

Late embryogenesis abundant (LEA) proteins in Ramonda serbica Panc identification, classification and structural characterization

An ancient resurrection plant Ramonda serbica Panc. is able to survive a long desiccation period and reestablish metabolic activity upon watering. A hallmark of desiccation tolerance in the resurrection species is the accumulation of protective late embryogenesis abundant proteins (LEAPs). These intrinsically disordered proteins (IDPs) may stabilize the correct structure of proteins and membranes during cellular dehydration. The aim of our study was to assess LEA genes’ expression levels in hydrated (HL) and desiccated leaves (DL) and to identify, characterise, and estimate the potential role of R. serbica LEAPs in desiccation tolerance. In total, 318 LEAPs from HL and DL were identified and classified into the seven LEA protein family groups ranging from LEA1-LEA5, seed maturation proteins (SMPs), and dehydrins (DEH). Analysis of the physicochemical properties, motif architecture, secondary structure, homology, and phylogenetic relationships demonstrated that R. serbica LEAPs greatly differed among the LEA family groups. The most abundant LEA2 proteins (mostly downregulated upon desiccation) exhibited lower hydrophilicity and propensity to fold into organised globular domains. Oppositely, hydrophilic LEA4 proteins tended to form amphipathic, A-type, α-helices. Most of desiccation-upregulated LEA genes encoded highly disordered DEH1, LEA1, LEA4.2, and LEA4.3 proteins. While dehydrins might chelate metals and bind DNA under water deficit, other ID LEAPs (e.g. LEA1, LEA3, LEA4) might participate in forming intracellular proteinaceous condensates or adopt amphipathic α-helical conformation, enabling them to stabilise desiccation-sensitive proteins and membranes. Taken together, possible functions of LEAPs are discussed with significant implications on drought tolerance improvement of crops grown in arid areas.Book of Abstracts: 4th International Conference on Plant Biology [and] 23rd SPPS Meeting, 6-8 October 2022, Belgrad