Ericoid shrub encroachment shifts aboveground-belowground linkages in three peatlands across Europe and Western Siberia.

In northern peatlands, reduction of Sphagnum dominance in favour of vascular vegetation is likely to influence biogeochemical processes. Such vegetation changes occur as the water table lowers and temperatures rise. To test which of these factors has a significant influence on peatland vegetation, we conducted a 3-year manipulative field experiment in Linje mire (northern Poland). We manipulated the peatland water table level (wet, intermediate and dry; on average the depth of the water table was 17.4, 21.2 and 25.3 cm respectively), and we used open-top chambers (OTCs) to create warmer conditions (on average increase of 1.2°C in OTC plots compared to control plots). Peat drying through water table lowering at this local scale had a larger effect than OTC warming treatment per see on Sphagnum mosses and vascular plants. In particular, ericoid shrubs increased with a lower water table level, while Sphagnum decreased. Microclimatic measurements at the plot scale indicated that both water-level and temperature, represented by heating degree days (HDDs), can have significant effects on the vegetation. In a large-scale complementary vegetation gradient survey replicated in three peatlands positioned along a transitional oceanic-continental and temperate-boreal (subarctic) gradient (France-Poland-Western Siberia), an increase in ericoid shrubs was marked by an increase in phenols in peat pore water, resulting from higher phenol concentrations in vascular plant biomass. Our results suggest a shift in functioning from a mineral-N-driven to a fungi-mediated organic-N nutrient acquisition with shrub encroachment. Both ericoid shrub encroachment and higher mean annual temperature in the three sites triggered greater vascular plant biomass and consequently the dominance of decomposers (especially fungi), which led to a feeding community dominated by nematodes. This contributed to lower enzymatic multifunctionality. Our findings illustrate mechanisms by which plants influence ecosystem responses to climate change, through their effect on microbial trophic interactions.

Antimicrobial Activity of Quercetin, Naringenin and Catechin: Flavonoids Inhibit Staphylococcus aureus-Induced Hemolysis and Modify Membranes of Bacteria and Erythrocytes.

Search for novel antimicrobial agents, including plant-derived flavonoids, and evaluation of the mechanisms of their antibacterial activities are pivotal objectives. The goal of this study was to compare the antihemolytic activity of flavonoids, quercetin, naringenin and catechin against sheep erythrocyte lysis induced by α-hemolysin (αHL) produced by the Staphylococcus aureus strain NCTC 5655. We also sought to investigate the membrane-modifying action of the flavonoids. Lipophilic quercetin, but not naringenin or catechin, effectively inhibited the hemolytic activity of αHL at concentrations (IC50 = 65 ± 5 µM) below minimal inhibitory concentration values for S. aureus growth. Quercetin increased the registered bacterial cell diameter, enhanced the fluidity of the inner and surface regions of bacterial cell membranes and raised the rigidity of the hydrophobic region and the fluidity of the surface region of erythrocyte membranes. Our findings provide evidence that the antibacterial activities of the flavonoids resulted from a disorder in the structural organization of bacterial cell membranes, and the antihemolytic effect of quercetin was related to the effect of the flavonoid on the organization of the erythrocyte membrane, which, in turn, increases the resistance of the target cells (erythrocytes) to αHL and inhibits αHL-induced osmotic hemolysis due to prevention of toxin incorporation into the target membrane. We confirmed that cell membrane disorder could be one of the direct modes of antibacterial action of the flavonoids.

Comparative analysis of molecular properties and reactions with oxidants for quercetin, catechin, and naringenin.

Flavonoids, a large group of secondary plant phenolic metabolites, are important natural antioxidants and regulators of cellular redox balance. The present study addressed evaluation of the electronic properties of some flavonoids belonging to different classes such as quercetin (flavonols), catechin (flavanols), and naringenin (flavanones) and their interactions with oxidants in model systems of DPPH reduction, flavonoid autoxidation, and chlorination. According to our ab initio calculations, the high net negative excess charges of the C rings and the small positive excess charges of the B rings of quercetin, catechin, and naringenin make these parts of flavonoid molecules attractive for electrophilic attack. The 3'-OH group of the B ring of quercetin has the highest excess negative charge and the lowest energy of hydrogen atom abstraction for the flavonoids studied. The apparent reaction rate constants (s-1, 20 °C) and the activation energies (kJ/mol) of DPPH reduction were 0.34 ± 0.06 and 23.0 ± 2.5 in the case of quercetin, 0.09 ± 0.02 and 32.5 ± 2.5 in the case of catechin, respectively. The stoichiometry of the DPPH-flavonoid reaction was 1:1. The activation energies (kJ/mol) of quercetin and catechin autoxidations were 50.8 ± 6.1 and 58.1 ± 7.2, respectively. Naringenin was not oxidized by the DPPH radical and air oxygen (autoxidation) and the flavonoids studied effectively prevented HOCl-induced hemolysis due to direct scavenging of hypochlorous acid (flavonoid chlorination). The best antioxidant quercetin had the highest value of HOMO energy, a planar structure and optimal electron orbital delocalization on all the phenolic rings due to the C2=C3 double bond in the C ring (absent in catechin and naringenin).

Ferutinin Induces Membrane Depolarization, Permeability Transition Pore Formation, and Respiration Uncoupling in Isolated Rat Liver Mitochondria by Stimulation of Ca2+-Permeability.

It is well known that the terpenoid ferutinin (4-oxy-6-(4-oxybenzoyloxy) dauc-8,9-en), isolated from the plant Ferula tenuisecta, considerably increases the permeability of artificial and cellular membranes to Ca2+-ions and produces apoptotic cell death in different cell lines in a mitochondria-dependent manner. The present study was designed for further evaluation of the mechanism(s) of mitochondrial effects of ferutinin using isolated rat liver mitochondria. Our findings provide evidence for ferutinin at concentrations of 5-27 µM to decrease state 3 respiration and the acceptor control ratio in the case of glutamate/malate as substrates. Ferutinin alone (10-60 µM) also dose-dependently dissipated membrane potential. In the presence of Ca2+-ions, ferutinin (10-60 µM) induced considerable depolarization of the inner mitochondrial membrane, which was partially inhibited by EGTA, and permeability transition pore formation, which was diminished partly by cyclosporin A, and did not influence markedly the effect of Ca2+ on mitochondrial respiration. Ruthenium Red, a specific inhibitor of mitochondrial calcium uniporter, completely inhibited Ca2+-induced mitochondria swelling and membrane depolarization, but did not affect markedly the stimulation of these Ca2+-dependent processes by ferutinin. We concluded that the mitochondrial effects of ferutinin might be primarily induced by stimulation of mitochondrial membrane Ca2+-permeability, but other mechanisms, such as driving of univalent cations, might be involved.

Calcium-Induced Mitochondrial Permeability Transitions: Parameters of Ca2+ Ion Interactions with Mitochondria and Effects of Oxidative Agents.

We evaluated the parameters of Ca2+-induced mitochondrial permeability transition (MPT) pore formations, Ca2+ binding constants, stoichiometry, energy of activation, and the effect of oxidative agents, tert-butyl hydroperoxide (tBHP), and hypochlorous acid (HOCl), on Ca2+ -mediated process in rat liver mitochondria. From the Hill plot of the dependence of MPT rate on Ca2+ concentration, we determined the order of interaction of Ca2+ ions with the mitochondrial sites, n = 3, and the apparent Kd = 60 ± 12 µM. We also found the apparent Michaelis-Menten constant, Km, for Ca2+ interactions with mitochondria to be equal to 75 ± 20 µM, whereas that in the presence of 300 µM tBHP was 120 ± 20 µM. Using the Arrhenius plots of the temperature dependences of apparent mitochondrial swelling rate at various Ca2+ concentrations, we calculated the activation energy of the MPT process. ΔEa was 130 ± 20 kJ/mol at temperatures below the break point of the Arrhenius plot (30-34 °C) and 50 ± 9 kJ/mol at higher temperatures. Ca2+ ions induced rapid mitochondrial NADH depletion and membrane depolarization. Prevention of the pore formation by cyclosporin A inhibited Ca2+-dependent mitochondrial depolarization and Mg2+ ions attenuated the potential dissipation. tBHP (10-150 µM) dose-dependently enhanced the rate of MPT opening, whereas the effect of HOCl on MPT depended on the ratio of HOCl/Ca2+. The apparent Km of tBHP interaction with mitochondria in the swelling reaction was found to be Km = 11 ± 3 µM. The present study provides evidence that three calcium ions interact with mitochondrial site with high affinity during MPT. Ca2+-induced MPT pore formations due to mitochondrial membrane protein denaturation resulted in membrane potential dissipation. Oxidants with different mechanisms, tBHP and HOCl, reduced mitochondrial membrane potential and oxidized mitochondrial NADH in EDTA-free medium and had an effect on Ca2+-induced MPT onset.

Cranberry flavonoids prevent toxic rat liver mitochondrial damage in vivo and scavenge free radicals in vitro.

The present study was undertaken for further elucidation of the mechanisms of flavonoid biological activity, focusing on the antioxidative and protective effects of cranberry flavonoids in free radical-generating systems and those on mitochondrial ultrastructure during carbon tetrachloride-induced rat intoxication. Treatment of rats with cranberry flavonoids (7 mg/kg) during chronic carbon tetrachloride-induced intoxication led to prevention of mitochondrial damage, including fragmentation, rupture and local loss of the outer mitochondrial membrane. In radical-generating systems, cranberry flavonoids effectively scavenged nitric oxide (IC50 = 4.4 ± 0.4 µg/ml), superoxide anion radicals (IC50 = 2.8 ± 0.3 µg/ml) and hydroxyl radicals (IC50 = 53 ± 4 µg/ml). The IC50 for reduction of 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH) was 2.2 ± 0.3 µg/ml. Flavonoids prevented to some extent lipid peroxidation in liposomal membranes and glutathione oxidation in erythrocytes treated with UV irradiation or organic hydroperoxides as well as decreased the rigidity of the outer leaflet of the liposomal membranes. The hepatoprotective potential of cranberry flavonoids could be due to specific prevention of rat liver mitochondrial damage. The mitochondria-addressed effects of flavonoids might be related both to radical-scavenging properties and modulation of various mitochondrial events.

DTPA(DOTA)-Nimotuzumab Radiolabeling with Generator-produced Thorium for Radioimmunotherapy of EGFR-overexpressing Carcinomas.

INTRODUCTION: The feasibility of preparing the "in-house" generators and the Th- DTPA(DOTA)-Nimotuzumab radioimmunoconjugate was evaluated. 226Th is perspective for TAT, however, due to short half-life it is preferable to apply this radionuclide for readily available epithelial malignancies. Nimotuzumab being specific for EGFR expressing cells as a targeting moiety is considered to be suitable for thorium delivery. METHODS: TEVA extraction chromatographic resin and anion exchange resin AG 1x8 were used as sorbents for 226Th generator. In order to determine features of labeling by Th4+ we applied 234Th as a longer-lived analog of short-lived 226Th and the immunoconjugates DTPA(DOTA)-Nimotuzumab were used for radiolabeling. RESULTS: The generator on the base of TEVA resin has shown higher volume activity of the product compared to the AG 1x8. The 226Th volume concentration was up to 80%/mL. The radiolabeling of BFCA by thorium radioisotopes reached 95% at the MR(Th:p-SCN-Bn-DTPA) = 1:100 and 86% for MR(Th:p-SCN-Bn-DOTA) = 1:5000 at 90°C. The procedure of Nimotuzumab labeling with Th4+ for radiotherapy of EGFR-overexpressing carcinomas was established. The overall labeling yield in both radioimmunoconjugates - DTPA and DOTA functionalized - was in the range of 45-50%. The immunoconjugate Nimotuzumab-p-SCN-Bn-DTPA was obtained with a molar ratio 1:25 (Nimotuzumab: BFCA), within 1 hour of conjugation at 25°C and labelled via postconjugation approach. Whereas Nimotuzumab-p-SCN-Bn-DOTA was obtained at the same conditions, but radiolabeled by the method of pre-conjugation. CONCLUSION: Thorium-234 incorporation into both radioimmunoconjugates reached 45-50%. It has been shown that Th-DTPA-Nimotuzumab radioimmunoconjugate specifically bound with EGFR overexpressing epidermoid carcinoma A431 cells.

Yugra State University Biological Collection (Khanty-Mansiysk, Russia): general and digitisation overview.

BACKGROUND: The history of biological collections and digitisation initiatives in northern West Siberia is relatively new due to recent development of the region. The Center for Biodiversity Data Mobilization was established to promote the initiative, led by the Yugra State University. This organisation itself has a relatively young collection of biological specimens, which was, until recently, in a disintegrated state and only partly mobilised. The Yugra State University Biological Collection (YSU BC) currently includes three subdivisions differring by history and taxonomic groups, but also by details of management and storage conditions: the Fungarium, the Bryological collection and the Herbarium collection of YSU.The paper describes the general structure of the Yugra State University Biological Collection, its history, storage conditions, management practices, geographical, temporal and taxonomical coverage. The paper is underlined by three datasets of the collections databases published in GBIF, which are described in detail. The databases are managed in Specify 6 and 7 software and accessed through Specify Web Portal and through GBIF. NEW INFORMATION: The Yugra State University Biological Collection made an active reorganisation of physical storage conditions and data management recently, providing the model for other collections in the region. This paper describes the history, general structure, management practices and data management of all three parts of this collection for the first time.Although one part of the collection (Fungarium YSU) was mobilised earlier, last year, we mobilised data of the Bryological and Vascular plants (Herbarium) collections. The three datasets of the corresponding collections in GBIF were increased by about 6000 georeferenced records during the last year.

Hydrolysable tannins change physicochemical parameters of lipid nano-vesicles and reduce DPPH radical - Experimental studies and quantum chemical analysis.

Tannins belong to plant secondary metabolites exhibiting a wide range of biological activity. One of the important aspects of the realization of the biological effects of tannins is the interaction with lipids of cell membranes. In this work we studied the interaction of two hydrolysable tannins: 1,2,3,4,6-penta-O-galloyl-ß-d-glucose (PGG) and 1,2-di-O-galloyl-4,6-valoneoyl-ß-d-glucose (T1) which had the same number of both aromatic rings (5) and hydroxyl groups (15) but differing in flexibility due to the presence of valoneoyl group in the T1 molecule with DMPC (dimyristoylphosphatidylcholine) lipid nano-vesicles (liposomes). Tannins-liposomes interactions were investigated using fluorescence spectroscopy, differential scanning calorimetry, laser Doppler velocimetry, dynamic light scattering and Fourier Transform Infra-Red spectroscopy. It was shown that more flexible PGG molecules stronger decreased the microviscosity of the liposomal membranes and increased the values of negative zeta potential in comparison with the more rigid T1. Both compounds diminished the phase transition temperature of DMPC membranes, interacted with liposomes via PO groups of head of phospholipids and their hydrophobic regions. These tannins neutralized DPPH free radicals with the stoichiometry of the reaction equal 1:1. The effects of the studied compounds on liposomes were discussed in relation to tannin quantum chemical parameters calculated by molecular modeling.

Endangered plants persist under phosphorus limitation.

Nitrogen enrichment is widely thought to be responsible for the loss of plant species from temperate terrestrial ecosystems. This view is based on field surveys and controlled experiments showing that species richness correlates negatively with high productivity and nitrogen enrichment. However, as the type of nutrient limitation has never been examined on a large geographical scale the causality of these relationships is uncertain. We investigated species richness in herbaceous terrestrial ecosystems, sampled along a transect through temperate Eurasia that represented a gradient of declining levels of atmospheric nitrogen deposition--from approximately 50 kg ha(-1) yr(-1) in western Europe to natural background values of less than 5 kg ha(-1) yr(-1) in Siberia. Here we show that many more endangered plant species persist under phosphorus-limited than under nitrogen-limited conditions, and we conclude that enhanced phosphorus is more likely to be the cause of species loss than nitrogen enrichment. Our results highlight the need for a better understanding of the mechanisms of phosphorus enrichment, and for a stronger focus on conservation management to reduce phosphorus availability.

Corrections by melatonin of liver mitochondrial disorders under diabetes and acute intoxication in rats.

The aim of the present work was to investigate the mechanisms of oxidative damage of the liver mitochondria under diabetes and intoxication in rats as well as to evaluate the possibility of corrections of mitochondrial disorders by pharmacological doses of melatonin. The experimental (30 days) streptozotocin-induced diabetes mellitus caused a significant damage of the respiratory activity in rat liver mitochondria. In the case of succinate as a respiratory substrate, the ADP-stimulated respiration rate V3 considerably decreased (by 25%, p < 0·05) as well as the acceptor control ratio (ACR) V3/V2 markedly diminished (by 25%, p < 0·01). We observed a decrease of the ADP-stimulated respiration rate V3 by 35% (p < 0·05), with glutamate as substrate. In this case, ACR also decreased (by 20%, p < 0·05). Surprisingly, the phosphorylation coefficient ADP/O did not change under diabetic liver damage. Acute rat carbon tetrachloride-induced intoxication resulted in considerable decrease of the phosphorylation coefficient because of uncoupling of the oxidation and phosphorylation processes in the liver mitochondria. The melatonin administration during diabetes (10 mg·kg⁻¹ body weight, 30 days, daily) showed a considerable protective effect on the liver mitochondrial function, reversing the decreased respiration rate V3 and the diminished ACR to the control values both for succinate-dependent respiration and for glutamate-dependent respiration. The melatonin administration to intoxicated animals (10 mg·kg⁻¹ body weight, three times) partially increased the rate of succinate-dependent respiration coupled with phosphorylation. The impairment of mitochondrial respiratory plays a key role in the development of liver injury under diabetes and intoxication. Melatonin might be considered as an effector that regulates the mitochondrial function under diabetes.

Connecting biodiversity and human dimensions through ecosystem services: The Numto Nature Park in West Siberia.

An assessment of the socio-ecological system of the Nature Park "Numto" in West Siberia was carried out based on ecosystem services (ES) mapping, applying a "cascade approach" which was modified according to the specific conditions of low commercial land-use by Indigenous Peoples and adopted with a focus on making it practicable and understandable by decision-makers. The ES values were defined through stakeholder analysis, while the mapping was based on the biophysical traits of the ecosystems and related spatial distribution of ecosystem functions. The mapped ecosystem values differ from the perceived ones. The assessment identified conflicting land uses and groups of stakeholders, including Indigenous Peoples vulnerable to future climate change-induced deficits in access to ES. The ES that are important for climate change mitigation and adaptation are not valued highly by Indigenous Peoples. ES mapping is suggested as an appropriate method for the development of straightforward recommendations for Nature Park management.

Role of mitochondrial calcium in hypochlorite induced oxidative damage of cells.

Hypochlorite (HOCl) is one of the most important mediators of inflammatory processes. Recent evidence demonstrates that changes in intracellular calcium pool play a significant role in the damaging effects of hypochlorite and other oxidants. Mitochondria are shown to be one of the intracellular targets of hypochlorite. But little is known about the mitochondrial calcium pool changes in HOCl-induced mitochondrial dysfunction. Using isolated rat liver mitochondria, we showed the oxidative damage of mitochondria (GSH oxidation and mixed protein-glutathione formation without membrane lipid peroxidation) and alterations in the mitochondrial functional parameters (decrease of respiratory activity and efficiency of oxidative phosphorylation, NADH and FADH coenzyme levels, and membrane potential) under hypochlorite action (50-300 µM). Simultaneously, the mitochondrial calcium release and swelling were demonstrated. In the presence of EGTA, the damaging effects of HOCl were less pronounced, reflecting direct involvement of mitochondrial Ca2+ in mechanisms of oxidant-induced injury. Furthermore, exposure of HeLa cells to hypochlorite resulted in a considerable increase in cytoplasmic calcium concentrations and a decrease in mitochondrial ones. Applying specific inhibitors of calcium transfer systems, we demonstrated that mitochondria play a key role in the redistribution of cytoplasmic Ca2+ ions under hypochlorite action and act as mediators of calcium release from the endoplasmic reticulum into the cytoplasm.

Key periods of peatland development and environmental changes in the middle taiga zone of Western Siberia during the Holocene.

The response of peatlands to climate change can be highly variable. Through understanding past changes we can better predict the response of peatlands to future climate change. We use a multi-proxy approach to reconstruct the surface wetness and carbon accumulation of the Mukhrino mire (Western Siberia), describing the development of the mire since peat formation in the early Holocene, around 9360 cal. year BP. The mire started as a rich fen which initiated after paludification of a spruce forest (probably in response to a wetter climate), while the Mukhrino mire progressed to ombrotrophic bog conditions (8760 cal. year BP). This transition coincided with the intensive development of mires in Western Siberia and was associated with active carbon accumulation (31 g m-2 year-1). The ecosystem underwent a change to a tree-covered state around 5860 cal. year BP, likely in response to warming and possible droughts and this accompanied low carbon accumulation (12 g m2 year-1). If the future climate will be warmer and wetter, then regional mires are likely to remain a carbon sink, alternatively, a reversion to the wooded state with reduced carbon sink strength is possible.

Great Vasyugan Mire: How the world's largest peatland helps addressing the world's largest problems.

Peatlands cover 3% of the land, occur in 169 countries, and have-by sequestering 600 Gt of carbon-cooled the global climate by 0.6 °C. After a general review about peatlands worldwide, this paper describes the importance of the Great Vasyugan Mire and presents suggestions about its protection and future research. The World's largest peatland, the Great Vasyugan Mire in West-Siberia, forms the border between the Taiga and the Forest-Steppe biomes and harbours rare species and mire types and globally unique self-organizing patterns. Current oil and gas exploitation may arguably be largely phased out by 2050, which will pave the way for a stronger focus on the mire's role in buffering climate change, maintaining ecosystem diversity, and providing other ecosystem services. Relevant new research lines will benefit from the extensive data sets that earlier studies have gathered for other purposes. Its globally unique character as the 'largest life form on land' qualifies the Great Vasyugan Mire in its entirety to be designated as a UNESCO World Heritage Site and a Ramsar Wetland of International Importance.

Flavonoids modulate liposomal membrane structure, regulate mitochondrial membrane permeability and prevent erythrocyte oxidative damage.

In the present work, we investigated the interaction of flavonoids (quercetin, naringenin and catechin) with cellular and artificial membranes. The flavonoids considerably inhibited membrane lipid peroxidation in rat erythrocytes treated with tert-butyl hydroperoxide (700 µM), and the IC50 values for prevention of this process were equal to 9.7 ± 0.8 µM, 8.8 ± 0.7 µM, and 37.8 ± 4.4 µM in the case of quercetin, catechin and naringenin, respectively, and slightly decreased glutathione oxidation. In isolated rat liver mitochondria, quercetin, catechin and naringenin (10-50 µM) dose-dependently increased the sensitivity to Ca2+ ions - induced mitochondrial permeability transition. Using the probes TMA-DPH and DPH we showed that quercetin rather than catechin and naringenin strongly decreased the microfluidity of the 1,2-dimyristoyl-sn-glycero-3-phosphocholine liposomal membrane bilayer at different depths. On the contrary, using the probe Laurdan we observed that naringenin transfer the bilayer to a more ordered state, whereas quercetin dose-dependently decreased the order of lipid molecule packing and increased hydration in the region of polar head groups. The incorporation of the flavonoids, quercetin and naringenin and not catechin, into the liposomes induced an increase in the zeta potential of the membrane and enlarged the area of the bilayer as well as lowered the temperature and the enthalpy of the membrane phase transition. The effects of the flavonoids were connected with modification of membrane fluidity, packing, stability, electrokinetic properties, size and permeability, prevention of oxidative stress, which depended on the nature of the flavonoid molecule and the nature of the membrane.

Spectroscopic, Zeta-potential and Surface Plasmon Resonance analysis of interaction between potential anti-HIV tannins with different flexibility and human serum albumin.

Tannins belong to secondary metabolites of plants that exhibit a variety of biological activities, including antiviral one. In this research, we studied the interaction of human serum albumin (HSA) with two ellagitannins: 2,4-valoneoyl-3,6-hexahydroxydiphenoyl-ß-d-glucose (T1) and 1,2-di-O-galloyl-3,6-valoneoyl-ß-d-glucose (T2) from Euphorbia species having antiviral potential against HIV and differing in molecular flexibility due to the presence of valoneoyl- and hexahydroxydiphenoyl groups. A fluorescence analysis demonstrated that the tannins studied strongly interacted with HSA and quenched tryptophan (Trp) fluorescence in the range of 0.25-4 µM. The quenching occurred by a static mechanism. The logKb for more flexible T2 was generally higher in comparison with stiffer T1 (4.94 ±â€¯0.82 vs. 4.12 ±â€¯0.31 and 4.94 ±â€¯0.53 vs. 4.07 ±â€¯0.45 for 296 K and 303 K respectively). The difference was also in the nature of the forces participating in the interaction with HSA. The stiff T1 reacted with HSA via hydrophobic forces, whereas the flexible T2 interacted with the protein by van der Waals forces and hydrogen bonds. The nature of the bonds was also confirmed by a study of the hydrophobicity of the compounds. Zeta-potential measurements showed slightly modifications of albumin electric charge but without significant changes in the surface structure of protein. Surface Plasmon Resonance imaging (SPRi) revealed that the used tannins fully saturated a 3 ng/mL solution of albumin at the concentrations of above 15 ng/mL. Our experiments clearly showed that the tannins used formed complexes with HSA and that the flexibility of the tannins was an important factor determining their interaction with the protein.

Structure, stability, and antiplatelet activity of O-acyl derivatives of salicylic acid and lipophilic esters of acetylsalicylate.

The anti-thrombotic activity of acetylsalicylic acid (ASA) has been shown to be due to specific irreversible acetylation of blood platelet cyclooxygenase. The aim of our study was to investigate the associations between the antiplatelet activities of derivatives of both ASA and salicylic acid (SA), as well as the structure, stability, and molecular properties of these compounds. Homologous series of O-acyl derivatives of salicylic acid (propionyl-, butyrylsalicylic acids, PSA, BSA) and lipophilic dodecyl (C12)-, hexadecyl (C16)-, and cholesteryl acetylsalicylates were synthesized and tested for structure-activity relationships. The molecular properties (heat of formation, molecular surface area, dipole moment) of ASA and SA derivatives obtained by theoretical calculations changed with the increasing length of the acyl or alkyl residue. The inhibition of whole blood platelet aggregation and the reduction in thromboxane (TX) generation by O-acyl derivatives were concentration-dependent and decreased along with increasing the length of acyl hain. These effects correlated with the extent of platelet reactivity and P-selectin expression inhibition in collagen-activated platelets. In contrast to ASA and O-acyl derivatives of SA, none of the lipophilic ASA derivatives had a significant inhibitory effect on platelet aggregation. In conclusion, all SA and ASA derivatives studied under in vitro conditions showed much lower antiplatelet activities than ASA itself, despite their higher affinity to plasma proteins or membrane components and their equivalent ability to acetylate protein free amino groups.We suggest the significance of the carboxylic group, dipole moment, geometry, and size of these pharmaceuticals in their ability to bind to the active site of cyclooxygenase and their antiplatelet efficacy.

Sampling event dataset on five-year observations of macrofungi fruit bodies in raised bogs, Western Siberia, Russia.

BACKGROUND: The data paper includes the results of a long-term monitoring programme for macrofungi fruiting using permanent plots located in the raised bog ecosystem in central part of Western Siberia (nearby Khanty-Mansiysk), Russia. The goal of the project was to describe the quantitative and qualitative structure and spatial variation of the community of macromycetes, to follow its dynamics seasonally and inter-annually and also elucidate the relationship between the fruiting and climate variables. A total of 263 circular 5 m2 subplots (for a total area of 1,315 m2) were inspected weekly during vegetation seasons 2014-2018 and carpophores of different fungal taxa were counted. The resulting sampling-event dataset includes 16,569 of plot-based observations (= sampling events) with corresponding 6,011 occurrence records of macromycetes identified to species or genus level. In total, 69 species were revealed during the study. About 80% of plot-based observations contain zero records and mark absence of visible fruiting bodies in a certain plot and time. NEW INFORMATION: This is the first sampling-event dataset on plot-based observations of macrofungi published in GBIF and the first long-term series of macrofungi monitoring in a raised bog ecosystem accomplished in Western Siberia. The aim of the data paper publication was to provide the description and the link to the published data in the format of a peer-reviewed journal paper and to provide recognition for the effort by means of a scholarly article (based on Data paper definition published at https://www.gbif.org/en/data-papers).

Targeting the urine and plasma determinants of thromboxane A2 metabolism in detection of aspirin effectiveness.

Detection of reduced aspirin effectiveness has gained significant importance since clinical consequences of aspirin resistance were reported. Nevertheless, due to differentiated molecular basis of aspirin resistance, the conflicting choice of referential method for detection of acetylsalicylic acid ineffectiveness has become troublesome. This study, using a rat model of antiplatelet therapy, examines the aptitude of selected TXB2 metabolism-based methods in the detection of acetylsalicylic acid effectiveness. We hypothesized that ex-vivo whole blood spontaneous TXB2 generation assay could be, contrary to basal TXB2 and urine 11-dTXB2, a novel surrogate measure for impaired acetylsalicylic acid-dependent inhibition of thromboxane synthesis. To address this hypothesis, we evaluated the sensitivity of TXB2 generation assay in hirudinized whole blood to detect acetylsalicylic acid-mediated inhibition of cyclooxygenase activity in healthy rats and diabetic rats treated with acetylsalicylic acid. In diabetic and control animals, both acetylsalicylic acid drenches in the dose-independent manner contributed to significant attenuation of basal plasma TXB2 and urinary 11-dTXB2 formation. Urinary concentrations of 11-dTXB2 were, contrary to basal TXB2, significantly higher, regardless of acetylsalicylic acid dose, among all diabetic groups, compared with corresponding control groups. Determination of TXB2 generation in whole blood enabled sensitive detection of dose-related acetylsalicylic acid effect in both groups, as well as increased TXB2 formation in diabetes. We showed for the first time that evaluation of spontaneous generation of TXB2 in hirudinized whole blood enables, contrary to basal plasma TXB2 and urine 11-dTXB2 concentrations, to sensitively determine the acetylsalicylic acid effect in healthy and diabetic subjects.