15 research outputs found

    Effect of cadmium stress on antioxidative enzymes during the germination of Serbian spruce [Picea omorika (Pan..) Purkynĕ]

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    When considering the effect of heavy metals on trees generally and on forest ecosystems especially,Ā  importance is given to their influence on seed germination in metal polluted soil. There is insufficient data onĀ  this subject, especially when conifers are concerned. In this work, the influence of high cadmiumĀ  concentrations on percentage germination, specific activities and isoenzyme patterns of catalase (CAT),Ā  superoxide dismutase (SOD), and peroxidase (POD) during the germination of Serbian spruce [Picea omorika (Pan..) Purkynĕ] was studied. Cadmium chloride concentrations of up to 0.1 mM did not cause an inhibition of germination, while 1 mM concentration inhibited germination and the activities of catalase, superoxideĀ  dismutase and peroxidase. The isoenzyme profile of catalase and superoxide dismutase did not change at high cadmium concentrations, while peroxidase expression of basic peroxidase (B5) with pI value of 9.1 increased. This isoform of POD can play an important role in the early development of Serbian spruce and its defense mechanism against heavy metals.Key words: Seed germination, catalase, peroxidase, superoxide dismutase, heavy metals

    Serbian spruce, endemicity and advantages

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    Picea omorika (Pančić) Purkynĕ is Balkan endemic coniferous species and Tertiary relict of the European flora. Its natural habitat is fragmented and reduced to the middle and upper courses of the Drina River, in Western Serbia and Eastern Bosnia and Herzegovina. This region represents species long-term, cryptic and last refugium. The current limited natural range of Serbian spruce is mainly the result of the species poor competing ability. It retreats to areas less inhabitable by its competitors, predominantly Picea abies and Fagus orientalis. It inhabits open habitats, comprising cliffs and forest clearings, characterized by strong northerlywind, snow and rockfalls. Since the middle of the 19th century, its natural range declines continuously. Planting Serbian spruce outside its natural range has a long tradition, either as an ornamental tree species, or for afforestation, throughout Central and Northern Europe. Despite its endemism, P. omorika is considered as one of the most adaptable spruces. Wood properties are determined by cell arrangement, size and shape, and cell wall structure and thickness. Conifers, as a response to mechanical stress, such as wind and stem lean, form reaction wood called compression wood (CW). Its formation occurs on the lower side of the leaning stem, resulting in eccentric growth. Wood opposite to the CW in the same growth ring is termed opposite wood (OW), while wood from growth rings that do not contain any CW is termed normal wood (NW). CW is characterized by reduced tracheid length, rounder cell cross-sectional profile, presence of intercellular spaces, absence of the S3 cell wall layer and presence of helical cavities in S2 layer. Higher lignification, as one of the main characteristics of CW, is associated with changed lignin composition, increased amounts of phydroxyphenyl monomers and increased condensation of monomer units in the polymer. Consequently, CW contains less cellulose, with greatly increased amounts of galactan, and slightly lower amounts of mannan and xylan, and with higher angle of cellulose microfibrils in the S2 layer of the cell wall, compared to NW. CW occurs in a range of gradations from near NW to severe CW (SCW), mild CW (MCW) forming a continuum between NW and SCW. The degree of development of particular features of CW does not necessarily change in parallel to each other, so the severity of a given tracheid is represented as a function of the degrees of development of individual features, mainly lignification, helical cavities and cell wall thickness. Visual detection of compression wood severity, more precisely the determination of MCW, is difficult. As the severity of CW affects mechanical and chemical properties of wood in forest products industry it is desirable to be able to measure CW severity. We developed different morphometric and non-morphometric methods for distinguishing wood samples on a compression severity scale. They are based on tracheid double wall thickness, cellulose microfibrils order (distribution and alignment of cellulose microfibrils), or variation in lignin structure. We used confocal fluorescence microscopy and spectroscopy, and fluorescence-detected linear dichroism (FDLD) microscopy, combined with development of new algorithms and statistical analysis. We tested our methods on stem samples of P. omorika juvenile trees exposed to long term static bending. P. omorika belongs to slow-growing conifer species in which CW typically occurs in a severe form, while juvenile conifer wood is characterized by randomly distributed MCW, NW often being absent. These are the features that suggest P. omorika juvenile wood a good choice of samples for evaluation of the precision of methods suggested for estimation of compression wood severity. Our methods for distinguishing wood samples on a compression severity scale provide a fine gradation of juvenile P. omorika wood samples from NW to the severest form of CW, compression severity scales being partially different. The presented results qualify our methods for use in estimation of compression wood severity in forest products industries, individually or in combination, and confirm juvenile P. omorika stem samples as a good choice of samples for evaluation of the precision of methods suggested for compression wood severity estimation

    Serbian spruce (Picea omorika (Pančić) PurkynĆ©) - endemicity and advantages

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    Conifers, as a response to mechanical stress, such as wind and stem lean, form reaction wood called compression wood (CW). CW occurs in a range of gradations from near normal wood (NW) to severe CW (SCW). As the severity of CW affects the mechanical and chemical properties of wood, and as CW has limited value in the forest products industry, it is desirable to be able to measure CW severity. Picea omorika belong to slow-growing conifer species in which CW typically occurs in a severe form. We developed different morphometric and non-morphometric methods for estimation of CW severity tested on wood samples of P. omorika juvenile trees exposed to long term static bending. This specific review is aimed at presenting P. omorika as one of the most adaptable spruces, and as a good model for testing of methods for estimation of compression wood severity. First, we summarize main knowledge about P. omorika, features of CW, and methods for assessment of wood quality. Then, we present breifly our recently published methods for estimation of compression wood severity tested on P. omorika juvenile wood samples.Konifere kao odgovor na mehanički stres (vetar, savijanje) formiraju reakciono drvo koje se naziva kompresiono drvo (CW). CW se javlja u nizu gradacija od skoro normalnog drveta (NW) do jako izraženog CW (SCW). S obzirom da stepen izraženosti osobina CW ima značajan uticaj na mehaničke i hemijske osobine drveta i da CW ima ograničenu vrednost za drvnu industriju, poželjno je moći odrediti stepen izraženosti osobina CW u uzorku. Picea omorika spada u sporo rastuće četinarske vrste kod kojih se CW tipočno javlja u jako izraženoj formi. Mi smo razvili nekoliko morfometrijskih i ne-morfometrijskih metoda za procenu izraženosti osobina CW u uzorku, testiranih na uzorcima drveta juvenilnih stabala P. omorika koja su bila izložena dugotajnom statičkom savijanju. Ovaj revijski rad ima za cilj da predstavi Pančićevu omoriku kao jednu od najadaptabilnijih smrča i kao dobar model za testiranje metoda za procenu izraženosti osobina CW u uzorku. U prvom delu sumiramo znanja o Pančićevoj omorici, osobinama CW i metodama za procenu kvaliteta drveta, a u drugom ukratko predstavljamo naÅ”e nedavno objavljene metode za za procenu izraženosti osobina CW u uzorku, testirane na uzorcima drveta juvenilnih stabala P. omorika

    Klijanja semena Pančićeve omorike (Picea omorika (Pančić) Purkyně) i antioksidativni enzimi

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    Pančićeva omorika predstavlja Balkansku endemičnu vrstu smrče i tercijarni relikt. Određen je sastav antioksidativnih enzima tokom klijanja semena omorike u fizioloÅ”kim uslovima, a radi boljeg razumevanja mehanizama otpornosti na zagađivače iz spoljaÅ”nje sredine.1 Ovo je prva studija aktivnosti enzima katalaze (CAT), superoksid dismutaze (SOD) i peroksidaze (POD) tokom klijanja dve linije semena Pančićeve omorike (A ā€“ borealis i S ā€“ srpska). Klijanje semena je praćeno tokom 7 dana. Za procenat klijavosti koriŔćen je proboj radikule za viÅ”e od 1 milimetar kao kriterijum. Linija A je pokazala veći procenat klijavosti (74%) i veću aktivnost enzima po jedinici sveže mase klijanaca u poređenju sa linijom S (63%). CAT aktivnost kod linije A je povećana po jedinici mase klijanaca i suvih semena, a nakon 7 dana kod neisklijalih semena nije detektovana. SOD aktivnost je ostala na sličnom nivou u obe linije. Aktivnost POD na početku nije detektovana, ali se naglo povećala nakon četvrtog dana da bi sedmog bila 10 U/g sveže mase klijanaca kod linije S i 28 U/g kod A. CAT i SOD su uključeni u očuvanje klijavosti semena i imaju ulogu zaÅ”tite od reaktivnih kiseoničnih vrsta tokom skladiÅ”tenja i klijanja, dok je katalazna aktivnost bitna za procenu klijavosti. Najveću promenu aktivnosti za vreme klijanja pokazala je peroksidaza, čija aktivnost nije detektovana u suvim semenima, a tokom klijanja naglo se povećala i značajna je u kasnijim fazama klijanja

    Changes in sclerenchyma cell walls related to stem twining in Dioscorea balcanica

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    Dioscorea balcanica KoÅ”anin, family Dioscoreaceae, is an endemic, endangered liana species and a Tertiary relict of Balkan Peninsula. Gelatinous fibers, specialized sclerenchyma cells and well-known components of tension wood, are responsible for stem twining in liana plants. The aim of this investigation was to determine changes in sclerenchyma cell walls correlated with the twining process in liana plants. Our results showed that the differences in cell walls of sclerenchyma cells between straight and twisted internodes are not visible by light microscopy, but they are visible by SEM microscopy. In twisted internodes, cell walls of sclerenchyma cells in the region of contact with the support (ā€˜ā€˜tensionā€™ā€™ side of twisted internodes) appear smooth on the cross sections, suggesting cellulose microfibrils oriented almost parallel to the fiber axis. In contrast, cell walls of the entire ring of sclerenchyma cells in straight internodes, as well as cell walls of sclerenchyma cells on the ā€œoppositeā€ side of twisted internodes, appear jagged on the cross sections, suggesting cellulose microfibrils oriented at very high microfibril angle to the fiber axis. This result suggests that gelatinous fibers in D. balcanica stem have lignified G-layer, and thus could contribute to the understanding of ā€˜ā€˜late lignification of the G-layerā€™ā€™

    Differential Polarization Laser Scanning Microscopy (DP-LSM) -Technique for Rapid Screening of Cell Walls of Different Plant Species

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    DP-LS microscopy is a useful and easily applicable technique for rapid screening of cell wall structural order, by mapping the linear dichroism of cellulose fibrils. It allows screening and quantification of the alignment of cellulose fibrils, relative to one another, in cell walls. The goal was to provide new information about structural characteristics of the isolated cell walls among species which may be a basis for their possible applications, such as biofuel and biomaterial industry, but also to understand what plant response to stress is. The DP-LSM method is shown to be a simple and rapid way to check the structural complexity in the cell wall through cellulose labeling

    The relationship of physicochemical properties and structure to the antioxidative activity of free amino acids in the aqueous Fenton system

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    Iron is essential for plant growth, metabolism of mitochondria and chloroplasts, and a wide assortment of enzymes. However, it is also involved in Fenton reaction that generates hydroxyl radical (HOā€¢), the most reactive species in plants. The aim of our study was to examine the effects of amino acids on HOā€¢ production. The rank order according to antioxidative activity (AA) of amino acids in Fenton system was: Trp > Phe, Leu > Ile > His > Arg > Val > Lys, Tyr, Pro > Gln, Thr, Ser > Glu, Ala, Gly, Asn, Asp. Sulfur-containing amino acids generated different secondary reactive products, which were discriminated by EPR spin-trapping spectroscopy. AA showed positive correlation with hydrophobicity and negative correlation with polarity. HOā€¢provoked oxidation of amino acids was strongly positively affected by hydrophobic hydration. Group contribution method showed that the reactivity of amino acids with HOā€¢ is defined by the properties of side-chains (the contribution of NH3+CHCOOāˆ’ group and antioxidative activity of Gly were next to zero). Our results might shed a new light on the role of iron in the regulation of free amino acids pool and on protein oxidation in plants. According to our findings, native proteins (with exposed polar residues) might not be particularly susceptible to oxidation by HOā€¢. But once a protein is damaged and partially denatured it exposes hydrophobic side-chains and might become a likely target for HOā€¢, thus potentially acquiring an antioxidative role. Further research on change of redox properties of proteins with denaturation is warranted

    Ligand and redox - interactions of adrenaline with iron at physiological pH

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    Adrenaline (Adr) is catecholamine that is released by the sympathetic nervous system and adrenal medulla. It is involved in several physiological functions, including regulation of blood pressure, vasoconstriction, cardiac stimulation, and regulation of the blood glucose levels 1 . Transients of high levels of Adr in the bloodstream have been recognized for a long time as a cause of cardiovascular problems that develop under chronic exposure to psychosocial and physical stress 2,3. A number of studies have found a connection between the excess of Adr, cardiotoxic effects, and oxidative stress, that is irrespective of adrenergic receptors stimulation 2-4. The mechanism behind this involves Adr (coordinate and redox) interactions with iron, which are still not clear. Two main concepts have been proposed - Adr autooxidation and redox interactions with iron, the most abundant transition metal in human plasma 5 . Fe3+ is known to build complexes with catechols 6 , but data on Fe3+ coordinate interactions with Adr at physiological pH are missing. In addition to its (patho)physiological role, Adr is of interest from the aspect of development of catecholamine-rich biopolymers with adhesive properties and metelloorganic frameworks 7,8. The adhesion and other properties materials are based on the cross-linking via coordinate bonds with Fe3+ at pH > 7. Finally, ligands might dramatically alter the redox potential of Fe3+/Fe2+ couple 9 . It has been shown that specific ligands with high affinity for Fe3+, including some catechols, might promote the oxidation and increase the reactivity of Fe2+ with molecular oxygen 10. The aim of our study was to examine the nature of Adr interactions with Fe3+ and Fe2+: stoichiometry, sites of coordinate bonds formation and structure of complex(es), and redox activity, at pH 7.4 and different concentration ratios. The coordinate and redox interactions were investigated using UV/Vis spectrophotometry, low temperature EPR, Raman 143 spectroscopy, cyclic voltammetry, and oximetry. The stability of Adr in the studied reactions was monitored by HPLC. At pH 7.4, Adr forms complexes with Fe3+, in the 1:1, and 3:1 stoichiometry, depending on (high or low) Adr/Fe3+ concentration ratio. The high-spin Fe3+ 1:1 and 3:1 complexes show different symmetries, with the 3:1 complex displaying higher EPR spectral anisotropy. Raman spectroscopy showed that oxygen atoms on the catechol ring represent the sites of coordinate bond formation in the bidentate Adr-Fe3+ complex. The bonds appear to be stronger in the 1:1 complex, and not to share the same plane with the ring. On the other hand, Adr and Fe2+ build a complex that acts as a strong reducing agent. In the presence of O2, this leads to the production of H2O2, and to a facilitated formation of Adr/Fe3+ complexes. Adr is not oxidized in this process, i.e. iron is not an electron shuttle but electron donor. Catalyzed oxidation of Fe2+ in the presence of Adr represents a plausible chemical basis of stress-related damage of heart cells. In addition, our results imply that the application/pre-binding of Fe2+ followed by oxidation at pH > 7 might be a simple alternative strategy for promotion of cross-linking in catecholamine-rich biopolymers frameworks

    Correction to: Parenchyma cell wall structure in twining stem of Dioscorea balcanica (vol 24, pg 4653, 2017)

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    In the original publication of the article, one of the project numbers was omitted in the Acknowledgments. The correct version is provided below.Original publication: [http://cer.ihtm.bg.ac.rs/handle/123456789/2090

    Abts cation scavenging activity and total phenolic content of three moss species

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    Do sada je veoma malo proučavana antioksidativna aktivnost mahovina sa evropskog tla. Stoga je u ovom radu in vitro ispitivana sposobnost neutralizacije ABTS radikal katjona (2,2'-azinobis(3-etilbenzotiazolin-6-sulfonske kiseline)) i sadržaj ukupnih fenola vodenih ekstrakata tri vrste mahovine (Brachythecium rutabulum (Hedw.) Schimp. (Brachytheciaceae), Calliergonella cuspidata (Hedw.) Loeske (Hypnaceae) i Hypnum mammillatum (Brid.) Loeske (Hypnaceae)) sakupljene u Nemačkoj za vreme zimskog doba. Dobijeni rezultati ukazuju na to da ekstakt B. rutabulum može potencijalno da se smatra dobrim izvorom novih prirodnih supstanci sa antioksidativnom aktivnoŔću.A limited number of mosses have ever been studied in regard to antioxidant activity, with only a few belonging to the European species. As part of our ongoing screening of bryophytes as natural antioxidant resources, a relevant biological activity investigation was conducted on three moss species, namely Brachythecium rutabulum (Hedw.) Schimp. (Brachytheciaceae), Calliergonella cuspidata (Hedw.) Loeske (Hypnaceae) and Hypnum mammillatum (Brid.) Loeske (Hypnaceae), collected in Germany. The antioxidant activity of corresponding aqueous extracts was evaluated on the basis of their ABTS (2,2'-azino-bis(3- -ethylbenzthiazoline-6-sulphonic acid)) cation scavenging activities. The total phenolic contents were determined as well. This study led to the detection of a moderate total phenolic content of the moss B. rutabulum, indicating for the first time its potential in searching for novel antioxidant agents
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