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Impact of wastewater discharges on fatty acid profiles on roach (Rutilus rutilus) from Danube River, Belgrade
No full textPollution of freshwater ecosystems by discharges of untreated municipal wastewater represents a major threat for aquatic organisms and thus human health. Serbia discharges wastewater without previous treatment. In recent years, studies have shown that fatty acids are sensitive to alterations in organism homeostasis, supporting their use for biomarkers of toxicant exposure. Fish species are an important source of biologically valuable proteins, fats, fat-soluble vitamins, and n-3polyunsaturated fatty acids. The purpose of this study was to investigate the diferences of fatty acid composition in fish from urban sites of the Danube River. A total number of eight specimens of roach (Rutilus rutilus) were collected from two localities - Višnjica, which is exposed to the discharge of the largest wastewater collector in the city of Belgrade and Veliko Ratno Ostrvo, which is at the confluence of Danube and Sava River, and is considered as control location. Fatty acid methyl esters (FAMEs) were analyzed using gas chromatography–mass spectrometry (GC-MS). A total of 28 fatty acids were found in the muscle tissue of the studied fish species. The results showed no significant differences in fatty acid profile between polluted and control localities. All examined fish species contained essential fatty acids (EPA, ALA, DHA) with DHA levels significantly higher in specimens from control site. The proportion of total saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs) was almost the same while polyunsaturated fatty acids (PUFAs) were higher in control specimens. It is shown by previous studies that the main reason of changes in PUFAs is that they could be oxidized under oxidative stress conditions induced by metals or organic compounds. Even though anthropogenic load exerted on Višnjica locality has not significantly affected the fish fatty acid profile, changes in PUFAs indicated the presence of some xenobiotics in their environment
Functional iridoid synthases from three Nepeta species with differing iridoid profiles
No full textWithin a large iridoids-lacking clade of Nepetoidae (Lamiaceae), the genus Nepeta stands out as an exclusive producer of these atypical monoterpenes with a unique stereochemistry. The genus Nepeta exhibits a high diversity of iridoids, with nepetalactones (NLs) predominating; however, a few Nepeta species lack these compounds. Comparative metabolomics, transcriptomics, gene co-expression, and phylogenetic analysis were conducted on the trans,cis-NL-rich N. rtanjensis Diklić & Milojević, the cis,trans-NL-dominant N. sibirica L., and the iridoid-lacking N. nervosa Royle & Bentham, revealing significant structural and functional differences in their iridoid synthases (ISY). N. rtanjensis was found to have two orthologues of ISY (NrISY1 and NrISY2), while N. sibirica and N. nervosa each had only one ISY (NsISY and NnISY, respectively). Although the phylogenetic analysis grouped NrISY1, NsISY, and NnISY with non-active Family 1 isoforms, organ-specific expression highlighted NrISY2, NsISY, and NnISY as promising ISY candidates. In vitro assays confirmed their function and NrISY2 was the most efficient in converting 8-oxogeranial to cis,trans-nepetalactol. However, 3D modeling and molecular docking analyses suggested that NnISY may have a unique cyclase activity. Likely, under in vivo conditions, the NnISY lacks substrates to catalyze, as a result of the loss of upstream geraniol synthase (GES) activity, which results in the loss of iridoids in N. nervosa. Presumably, some of the downstream pathway genes (NEPSs and MLPLs), essential for the NL biosynthesis, also underwent structural and activity changes in this species. Our ongoing work is conducted towards testing these robust hypotheses and re-establishing iridoid biosynthesis in N. nervosa
Polycrystalline nickel modified with rhodium as an effective electrocatalyst for hydrogen-based energy conversion technologies
No full textThe electrode reactions of hydrogen and oxygen are of utmost importance to the technology of water electrolysis and fuel cells. Thus, developing advanced electrocatalysts is essential for meeting the energy needs of modern society. The work aimed to consider the potential of rapid galvanic displacement as a strategy for the design of advanced electrocatalysts and to examine the
electrocatalytic activity of polycrystalline nickel electrodes modified with rhodium for hydrogen
and oxygen evolution reactions (HER/OER), as well as for hydrogen oxidation reaction (HOR) and
oxygen reduction reaction (ORR) in an alkaline media. Modification of the surface of the nickel
electrode involves a simple and quick procedure of galvanic displacement using a concentrated
acidic solution of Rh3+ ions. Based on the assessed HER and OER overpotentials and the low values of Tafel slopes, the results show significant enhancement of the electrocatalytic activity for
these reactions on rhodium- modified electrodes. In contrast to pure nickel, the rhodium-modified
nickel electrode shows remarkable electrocatalytic activity for HOR and greatly improved activity
for ORR. However, its HOR and ORR performances are below the electrocatalytic activity of
polycrystalline platinum electrodes. This finding can be attributed to the detrimental role of
semiconducting Rh2O3 formed on the surface, which pertains to the HOR and ORR- operating
potentials. In contrast, OER occurs at higher potentials where conductive RhO2 is formed. This
research provides insight into the mechanisms underlying the improved electrode kinetics observed at rhodium-modified nickel electrodes and contributes to the understanding of the development of efficient and cost-effective electrocatalysts for renewable energy technologies
EUdaphobase - building bridges between cohabiting soil communities, environments, and methodologies
Get PDFAim: Edaphobase is a database previously constructed by the Senckenberg Natural Museum in Görlitz in Germany for the purpose of connecting soil invertebrate taxa to their environment. To extend Edaphobase into a warehouse for data on soil biodiversity at the European level and improve its usefulness, COST Action “EUdaphobase” was launched. Action gathers a network of European specialists working on enlarging existing capacities, and improving the technical capabilities, to provide a unique database that would be used by the different levels of stakeholders (from farmers, research and education institutions to decision makers). Taxonomists, ecologists, modelers of soil ecosystem processes, financial and IT specialists joined to form a holistic picture of soil biodiversity and introduce it into the decision-making process in Europe.
Method: WG 7 of EUdaphobase is focused on two goals - to enable a framework for integrating the data on fungi, bacteria and microeukaryotes, and collating the data derived by molecular methods (metabarcoding, NGS-based, environmental DNA/RNA), on all soil organism groups.
Results: The highly demanding technical problems of incorporating fungal and molecular data into the already existing framework of Edaphobase were resolved. The joint work of researchers working on different soil organisms and techniques resulted in the unique possibility for a variety of users to provide/analyze/use data that include cohabiting taxa, their environments, and mutual relationships.
Conclusions: The outcome will enable the usage of the upgraded Edaphobase for holistic soil state evaluation and monitoring, as well as monitoring of the dynamics of soil communities/environments involved in different ecosystem services on the European level.Abstract book was not published in hard copy and can be viewed on the congress site only https://gsb2023.org
Processing of gelatine coated composite scaffolds based on magnesium and strontium doped hydroxyapatite and yttria-stabilized zirconium oxide
No full textLimited bone bank capacity and risk of infection are some of the main drawbacks of autologous and allogenic grafts, giving rise to synthetic materials for bone tissue implants. The aim of this study was to process and evaluate the mechanical properties and bioactivity of magnesium and strontium doped hydroxyapatite (HAp) scaffolds and investigate the effect of adding zirconium oxide and gelatine coating the scaffolds. Doped nanosized hydroxyapatite powder was synthesized by the hydrothermal method and the scaffolds were made by the foam replica technique and sintered at different temperatures. Yttria-stabilized zirconium oxide (YSZ), synthesized by plasma technology, was used as reinforcement of calcium phosphate scaffolds. Element analysis, phase composition, morphology of the powders and microstructure of the scaffolds were investigated, as well as the compressive strength of the coated and uncoated scaffolds and bioactivity in simulated body fluid (SBF). A microporous structure was achieved with interconnected pores and bioactivity in SBF was confirmed in all cases. The best mechanical properties were given by the coated composite HAp/YSZ scaffolds, withstanding average stresses of over 1019 kPa. These results encourage the idea of use of these scaffolds in bone regenerative therapy and bone tissue engineering
Two contrasting late embryogenesis abounded protein family groups of Ramonda serbica Panc.
Get PDFRamonda serbica Panc. is an ancient resurrection plant, that survives a long desiccation period and fully recovers metabolic functions upon watering. The main characteristic of desiccationtolerant plant species is their ability to accumulate protective late embryogenesis abounded protein (LEAPs). To propose their role in R. serbica desiccation tolerance we structurally analysed LEAPs in hydrated and desiccated leaves. According to transcriptomics, 318 LEAPs were identified and classified into seven family groups based on protein BLAST analysis and conserved motifs (Pfam). The largest LEAPs belonged to the LEA2 and LEA4 protein family groups. We employed online tools to analyse physicochemical characteristics (Expasy, ProtParam, BioPython, GRAVY calculator), disorder propensity, and characterization protein structures (FELLS, JPred, SOPMA, PsiPred, Phyre2, Espritz-DisProt, Espritz-X, Iupred, TMHMM, +Heliquest). The most abundant, atypical LEA2 group containing 127, mostly hydrophobic proteins, was divided into five subgroups. Members of this group were predicted to fold into globular domains, β-barrel at the C-terminus, followed by transmembrane hydrophobic-helices and disordered N-terminal regions. Results indicated the possible involvement in the protection of the chloroplastic membranes. The LEA4 group exhibited an exceptionally high tendency to form amphipathic α-helices and simultaneously had a high disorder propensity. This group is made of 96 proteins, classified into 3 subgroups. The high content of polar and charged amino acids (lysine, glutamate, and aspartate) is characteristic of this group. Motifs corresponding to the R. serbica LEA4 protein family group folded into A-type α-helices that contained positive, negative, and hydrophobic surfaces. Based on previous knowledge, the possible functions of the LEA2 and LEA4 groups are discussed with significant implications on cell preservation technology and the improvement of crop drought tolerance
GIBBERELLIC ACID AS PRE-SOWING TREATMENT FOR TAXUS BACCATA SEEDS
Get PDFTaxus baccata (L.) je retka i zaštićena vrsta u šumama Srbije. Obnavljanje Taxus baccata u šumama je prepušteno prirodi i ne postoje podaci o proizvodnji
šumskih sadnica ove vrste u našim šumskim rasadnicima. Razmnožavanje Taxus
baccata za potrebe proizvodnje ukrasnog sadnog materijala se uglavnom sprovodi vegetativnim putem (reznicama), a generativno razmnožavanje ove vrste je
zanemareno usled izrazito dormantnog semena. Problem dormantnosti semena
Taxus baccata je dobro dokumentovan u literaturi, a preporučeni metodi za otklanjanje dormantnosti su dugotrajni i zasnivaju se na primeni tople i hladne, suve
ili vlažne stratifikacije u različitim trajanjima. Pored dužine trajanja stratifikacije,
problem predstavlja i relativno mala klijavost nakon primene neke od ovih metoda. Sa ciljem da se dormantnost otkloni i izazove klijanje u što većem procentu u
ovom radu je testiran uticaj giberelinske kiseline (GA4/GA7) na klijanje semena
Taxus baccata. Seme koje je sakupljeno sa 10 parkovskih stabala je podvrgnuto
suvo-hladnoj stratifikaciji i hladno-vlažnoj stratifikaciji u trajanju od 16 nedelja.
Uzorak od po 200 semena je potopljen 24 časa u rastvor giberelinske kiseline (100
ppm, 300 ppm i 500 ppm) i vodonik-peroksida, dok je isti broj semena iz obe vrste stratifikata posejan bez potapanja. Ogled je izvršen u dva ponavljanja za svaku
vrstu stratifikata, a sproveden je u staklari Šumarskog fakulteta Univerziteta u Beogradu. Klijanje semena je zabeleženo u proleće naredne godine, i trajalo je 2
meseca (maj-jun 2023 godine). Najveća klijavost semena je zabeležena u tretmanu giberelinske kiseline u najvećoj testiranoj koncentraciji bez obzira na vrstu prethodne stratifikacije (suvo-hladna 22.5%; vlažno-hladna 22.75%, u poređenju sa
kontrolisanim 10,5% za obe stratifikacije).Taxus baccata (L.) is a rare and protected species in the forests of Serbia. Taxus
baccata regeneration in forests is left to nature and there is no data on the production of forest seedlings of this species in our forest nurseries. Reproduction of
Taxus baccata for the purposes of production of decorative planting material is
mainly carried out vegetatively (by cuttings), and generative reproduction of this
species is neglected due to extremely dormant seeds. The problem of Taxus baccata
seed dormancy is well documented in the literature, and the recommended
methods for eliminating dormancy are long-term and based on the application
of hot and cold and dry or wet stratification for different durations. In addition to
the length of the stratification, the problem is also relatively low germination after
applying one of these methods. With the aim of removing dormancy and causing
germination in the highest possible percentage, this paper tested the influence of gibberellic acid (GA4/GA7) on the germination of Taxus baccata seeds. Seeds collected from 10 park trees were subjected to dry-cold stratification and cold-wet stratification for 16 weeks. A sample of 200 seeds each was immersed for 24 hours
in a solution of gibberellic acid (100 ppm, 300 ppm and 500 ppm) and hydrogen
peroxide, while the same number of seeds from both types of stratification was
sown without immersion. The experiment was carried out in two repetitions for
each type of stratification, and was conducted in the glasshouse of the Faculty of
Forestry, University of Belgrade. Seed germination was recorded in the spring of
the following year, and lasted for 2 months (May-June 2023). The highest seed
germination was recorded in the gibberellic acid treatment at the highest tested
concentration, regardless of the type of previous stratification (dry-cold 22.5%;
wet-cold 22.75%)
A fluorescence spectroscopic study of light transmission and adaxial-abaxial distribution of emitting compounds in leaves of Christmas star (Euphorbia pulcherrima)
No full textIn situ fluorescence measurements have been used to investigate relative amounts of blue-green pigments and
their distributions in plant leaves from Euphorbia pulcherrima. Advantage was taken from the fact that this species
has white leaves on the top, with low pigment concentrations, and green leaves on the stem with ordinary
pigment concentrations. Excitation- and emission spectra below 410 nm from white leaves, where pigment
absorption is low, are not distorted by self-absorption. Absorption- and reflection spectra from white and green
leaves were measured using a spectrophotometer equipped with an integrating sphere. The absorption spectra
were used to correct recorded fluorescence spectra for self-absorption. Self-absorption corrected photosystem
fluorescence from green leaves, modeling light transmission in leaf tissue exponentially, matches to the excitation/
emission spectra from white leaves, apart from small differences due to the pigment concentrations and
selective scattering. The introduced exponentially decaying transmission relation also predicts that the ratio of
excitation spectra from a white and green leaf is in proportion to the absorption spectrum of the green leaf, which
was validated for Photosystem II particle fluorescence. This relation was also used to find a scaled absorption
spectrum responsible for blue-green emission, which was assumed to originate from lignin. Excitation/emission
spectra of the blue-green fluorescence were decomposed into five components and their relative amounts from
adaxial and abaxial sides of the leaves have been quantified. Fluorescence lifetime measurements of the leaves
Lignin-based material for biomedical applications: Basic requirements and properties
No full textThe material selected for biomedical application must be biocompatible, stable against physiological media, non-toxic, non-carcinogenic, corrosion-resistant, bio-inert, and stimuli-responsive, and have a low wear rate. Lignin is the most abundant aromatic polymer on Earth with a complex, recalcitrant structure. A lot of knowledge is acquired on its pre-treatments and processing for biomedical uses in the forms of hydrogels, films, composite materials, nanoparticles, and aerogels. To avoid the potential toxicity and to control the cytotoxicity of lignin-based materials, it is necessary to increase the purity of the starting source materials and understand their reactivity. The poor water solubility, broad molecular weight (MW) distribution, and highly complex structure of lignin restrict its wider clinical applications. These limitations may be effectively improved by chemical modifications or by using lignin fractions with a narrow MW range. Antioxidant and antimicrobial properties allow lignin to be used in pharmaceuticals, drug delivery, and wound healing. It is also reported as a good candidate for composite materials intended for bone regeneration scaffolds in tissue engineering. Future challenges for lignin-based materials for biomedical applications include achieving a better understanding of the structure, isolation, and batch properties of lignin, as well as structure–function relationships in its applications
The behaviour of Kolubara and Kostolac lignite during devolatilisation process: A petrographical approach
Get PDFThe devolatilization process is the initial step in the coal combustion. Devolatilization research
was performed on a wire-mesh reactor in inert gas, at the atmospheric pressure. Two different
sets of feed coal samples of various particle diameters (0.50<х<1.00 mm; 0.25<x<0.50 mm;
0.1<x<0.25 mm; x<0.1 mm) from the Kolubara and Kostolac mines were used for research.
Lignite samples were spread in a thin layer a few particles thick, over electrically heated
stainless steel wire mesh and rapidly heated at four different temperature stages (300oC, 500oC,
700oC, 900oC). Maceral analysis and rank deternination were performed on 32 combustion
residues and 8 lignite samples following the classification developed by ICCP for lignite,
bituminous coal and coal chars