33 research outputs found
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..
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 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
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
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
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 (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
Application of differential pulse polarography in analysis of pectin
Differential pulse polarography (DPP) with dropping mercury electrode (DME)
was used to determine quantitatively galacturonic acid (GA), methylated
polygalacturonic acid (met PGA), pectin (PC) and pectinase (PE) in 0.1 M NaClO4
as supporting electrolyte. Current peaks of GA, met PGA, PC and PE, at -1.55, -
1.50, -1.40 and -1.60 V vs SCE respectively, were found suitable for quantitative
determination in the concentration range considered. Enzymatic reaction between
PE and PC was followed and possibility to determine simultaneously of PC and PE
was proved
LEAF NITROGEN BALANCE INDEX USED TO MONITOR STRESS RESPONSE TO AIR POLLUTION OF DECIDUOUS TREE SPECIES GROWN IN URBAN ZONE OF BELGRADE
Street trees are important component of urban forest presenting a first barrier between air pollution
originated from vehicle traffic and pedestrians. It implies that an improvement of air quality in urban
areas greatly depends on green biomass, in short, the bigger and greener tree crown, better for human
health and wellbeing. Determination of Leaf Nitrogen Balance Index (LNBI) and chlorophyll
concentration (ChlC) by a non-invasive methodology and a user friendly instrument (Dualex 4,
Force), widely used in agronomy and horticulture, was tested here for the assessment of tree fitness in
urban zones. Investment of energy and resources either in growth or defence according to the tradeoff
strategy of plants may be indicated by LNBI, which approximately presents a Nitrogen/Carbon
ratio. We selected few tree species from Belgrade’s streets to determine those two parameters during
summer. We also presented the changes in those parameters of the introduced bamboo species within
ten years at several urban locations in Belgrade differing in air pollution aiming to evaluate
usefulness the LNBI parameter in access of multiyear exposure to the effect of intense vehicle traffic.
Numerous limiting factors for development of healthy tree crowns in urban ecosystem, such as low
capacity to cope with toxic pollutant, sensitivity to diseases, early senescence and etc., greatly depends
on tree species. We propose this methodology may also contribute in the process of choice of the
adequate tree species to be planted along streets