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31.
Suzanne T. E. Lommen Caspar A. Hallmann Eelke Jongejans Bruno Chauvel Melinda Leitsch-Vitalos Alla Aleksanyan Peter Tóth Cristina Preda Maja Šćepanović Huseyin Onen Barbara Tokarska-Guzik Paulina Anastasiu Zita Dorner Annamária Fenesi Gerhard Karrer Katalin Nagy Gyula Pinke Viktor Tiborcz Gergely Zagyvai Mihály Zalai Gabriella Kazinczi Robert Leskovšek Danijela Stešević Guillaume Fried Levani Kalatozishvili Andreas Lemke Heinz Müller-Schärer 《Biological invasions》2018,20(6):1475-1491
To better manage invasive populations, it is vital to understand the environmental drivers underlying spatial variation in demographic performance of invasive individuals and populations. The invasive common ragweed, Ambrosia artemisiifolia, has severe adverse effects on agriculture and human health, due to its vast production of seeds and allergenic pollen. Here, we identify the scale and nature of environmental factors driving individual performance of A. artemisiifolia, and assess their relative importance. We studied 39 populations across the European continent, covering different climatic and habitat conditions. We found that plant size is the most important determinant in variation of per-capita seed and pollen production. Using plant volume as a measure of individual performance, we found that the local environment (i.e. the site) is far more influential for plant volume (explaining 25% of all spatial variation) than geographic position (regional level; 8%) or the neighbouring vegetation (at the plot level; 4%). An overall model including environmental factors at all scales performed better (27%), including the weather (bigger plants in warm and wet conditions), soil type (smaller plants on soils with more sand), and highlighting the negative effects of altitude, neighbouring vegetation and bare soil. Pollen and seed densities varied more than 200-fold between sites, with highest estimates in Croatia, Romania and Hungary. Pollen densities were highest on arable fields, while highest seed densities were found along infrastructure, both significantly higher than on ruderal sites. We discuss implications of these findings for the spatial scale of management interventions against A. artemisiifolia. 相似文献
32.
Kovacs K Hanto K Bognar Z Tapodi A Bognar E Kiss GN Szabo A Rappai G Kiss T Sumegi B Gallyas F 《Molecular and cellular biochemistry》2009,321(1-2):155-164
We studied cardioprotective as well as Akt and extracellular signal-activated kinase (ERK) activating effect of a Ca(2+) antagonist and a beta-adrenergic receptor blocker during ischemia-reperfusion, and compared these properties of the substances with that of a poly(ADP-ribose) polymerase (PARP) inhibitor used as a positive control throughout the experiments. Langendorff-perfused isolated rat hearts were subjected to 25 min global ischemia followed by 45 min reperfusion, and recovery of energy metabolism as well as functional cardiac parameters were monitored. Although to varying extents, all substances improved recovery of creatine phosphate, ATP, intracellular pH, and reutilization of inorganic phosphate. These favorable changes were accompanied by improved recovery of heart function parameters and reduced infarct size. In addition and again to varying extents, all studied substances decreased oxidative damage (lipid peroxidation and protein oxidation), and activated Akt, glycogen synthase kinase (GSK)-3beta, and ERK1/2. Correlation between cardioprotective and kinase activating effectivity of the compounds proved to be statistically significant. Physiological significance of these kinase activations was established by demonstrating that inhibition of Akt by LY294002 and ERK1/2 by PD98059 compromised the cardioprotective effect of all the substances studied. In conclusion, we demonstrated for the first time that activation of phosphatidylinositol-3-kinase (PI-3K)-Akt and ERK2 pathways significantly contributed to cardioprotective effects of a Ca(2+) antagonist and a beta-adrenergic receptor blocker. Furthermore, we found a strong correlation between cardioprotective and kinase-activating potencies of the substances studied (Verapamil, Metoprolol and two PARP inhibitors), which indicated the potentiality of these kinases as drug-targets in the therapy of ischemic heart disease. 相似文献
33.
Pilar Pérez Aitor Alonso Gloria Zita Rosa Morcuende Rafael Martínez-Carrasco 《Plant Growth Regulation》2011,65(3):439-447
Increases in growth temperature have been observed to affect photosynthesis differently under long-term exposure to ambient-
and twice ambient-air CO2 concentrations. This study investigates the causes of this interaction in wheat (Triticum aestivum L.) grown in the field over two consecutive years under temperature gradient chambers in ambient (370 μmol mol−1) or elevated (700 μmol mol−1) atmospheric CO2 concentrations and at ambient or ambient +4°C temperatures, with either a low or a high nitrogen supply. The photosynthesis-internal
CO2 response curves and the activity, activation state, kcat and amount of Ribulose-1, 5-bisphosphate carboxylase/oxygenase (Rubisco) were measured, as well as the soluble protein concentration
in flag leaves at ear emergence and 8–15 days after anthesis. A high nitrogen supply increased Vcmax, the Rubisco amount and activity and soluble protein contents, but did not significantly change the Rubisco kcat. Both elevated CO2 and above ambient temperatures had negative effects on Vcmax and Rubisco activity, but at elevated CO2, an increase in temperature did not decrease Vcmax or Rubisco activity in relation to ambient temperature. The amounts of Rubisco and soluble protein decreased with elevated
CO2 and temperature. The negative impact of elevated CO2 on Rubisco properties was somewhat counteracted at elevated temperatures by an increase in kcat. This effect can diminish the detrimental effects on photosynthesis of combined increases of CO2 and temperature. 相似文献
34.
Sándor Bartha Szilárd Szentes András Horváth Judit Házi Zita Zimmermann Csaba Molnár István Dancza Katalin Margóczi Róbert W. Pál Dragica Purger Dávid Schmidt Miklós Óvári Cecília Komoly Zsuzsanna Sutyinszki Gábor Szabó András István Csathó Melinda Juhász Károly Penksza Zsolt Molnár 《应用植被学》2014,17(2):201-213
35.
36.
Zita Kalchhofer 《Protoplasma》1936,26(1):249-281
Zusammenfassung Sprosse vonHelodea canadensis undTradescantia fluminensis, sowie Keimpflanzen vonVicia faba wurden in Mangellösungen kultiviert. Es wurde untersucht, ob die dabei zu erwartenden pathologischen Zellzustände durch die Methoden der protoplasmatischen Pflanzenanatomie und der vergleichenden Protoplasmatik charakterisiert werden können. 相似文献
37.
The effect of conjugation on antitumor activity of vindoline derivatives with octaarginine,a cell‐penetrating peptide
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Zoltán Bánóczi András Keglevich Ildikó Szabó Ivan Ranđelović Zita Hegedüs Fruzsina L. Regenbach Péter Keglevich Zsófia Lengyel Viktor Háda Áron Szigetvári László Hazai József Tóvári Ferenc Hudecz 《Journal of peptide science》2018,24(10)
Some Vinca alkaloids (eg, vinblastine, vincristine) have been widely used as antitumor drugs for a long time. Unfortunately, vindoline, a main alkaloid component of Catharanthus roseus (L.) G. Don, itself, has no antitumor activity. In our novel research program, we have prepared and identified new vindoline derivatives with moderate cytostatic activity. Here, we describe the effect of conjugation of vindoline derivative with oligoarginine (tetra‐, hexa‐, or octapeptides) cell‐penetrating peptides on the cytostatic activity in vitro and in vivo. Br‐Vindoline‐(l )‐Trp‐OH attached to the N‐terminus of octaarginine was the most effective compound in vitro on HL‐60 cell line. Analysis of the in vitro activity of two isomer conjugates (Br‐vindoline‐(l )‐Trp‐Arg8 and Br‐vindoline‐(d )‐Trp‐Arg8 suggests the covalent attachment of the vindoline derivatives to octaarginine increased the antitumor activity significantly against P388 and C26 tumour cells in vitro. The cytostatic effect was dependent on the presence and configuration of Trp in the conjugate as well as on the cell line studied. The configuration of Trp notably influenced the activity on C26 and P388 cells: conjugate with (l )‐Trp was more active than conjugate with the (d )‐isomer. In contrast, conjugates had very similar effect on both the HL‐60 and MDA‐MB‐231 cells. In preliminary experiments, conjugate Br‐vindoline‐(l )‐Trp‐Arg8 exhibited some inhibitory effect on the tumor growth in P388 mouse leukemia tumor‐bearing mice. Our results indicate that the conjugation of modified vindoline could result in an effective compound even with in vivo antitumor activity. 相似文献
38.
Szilvia Fóti János Balogh Marianna Papp Péter Koncz Dóra Hidy Zsolt Csintalan Péter Kertész Sándor Bartha Zita Zimmermann Marianna Biró László Hováth Erik Molnár Albert Szaniszló Krisztina Kristóf Györgyi Kampfl Zoltán Nagy 《Ecosystems》2018,21(1):112-124
Spatial patterns of ecosystem processes constitute significant sources of uncertainty in greenhouse gas flux estimations partly because the patterns are temporally dynamic. The aim of this study was to describe temporal variability in the spatial patterns of grassland CO2 and N2O flux under varying environmental conditions and to assess effects of the grassland management (grazing and mowing) on flux patterns. We made spatially explicit measurements of variables including soil respiration, aboveground biomass, N2O flux, soil water content, and soil temperature during a 4-year study in the vegetation periods at grazed and mowed grasslands. Sampling was conducted in 80 × 60 m grids of 10 m resolution with 78 sampling points in both study plots. Soil respiration was monitored nine times, and N2O flux was monitored twice during the study period. Altitude, soil organic carbon, and total soil nitrogen were used as background factors at each sampling position, while aboveground biomass, soil water content, and soil temperature were considered as covariates in the spatial analysis. Data were analyzed using variography and kriging. Altitude was autocorrelated over distances of 40–50 m in both plots and influenced spatial patterns of soil organic carbon, total soil nitrogen, and the covariates. Altitude was inversely related to soil water content and aboveground biomass and positively related to soil temperature. Autocorrelation lengths for soil respiration were similar on both plots (about 30 m), whereas autocorrelation lengths of N2O flux differed between plots (39 m in the grazed plot vs. 18 m in the mowed plot). Grazing appeared to increase heterogeneity and linkage of the spatial patterns, whereas mowing had a homogenizing effect. Spatial patterns of soil water content, soil respiration, and aboveground biomass were temporally variable especially in the first 2 years of the experiment, whereas spatial patterns were more persistent (mostly significant correlation at p < 0.05 between location ranks) in the second 2 years, following a wet year. Increased persistence of spatial patterns after a wet year indicated the recovery potential of grasslands following drought and suggested that adequate water supply could have a homogenizing effect on CO2 and N2O fluxes. 相似文献
39.
Rita Skoda-F ldes Zita Cs kai L szl Koll r G bor Szalontai Judit Horv th Zolt n Tuba 《Steroids》1995,60(12):786-790
17-Iodo-Δ16 steroids undergo selective dimerization and carbonylative dimerization in the presence of palladium catalysts in dimethylformamide which result in 16–17′-coupled dienes and 17-carboxylic anhydrides, respectively. Moderate to good yields have been obtained for both types of dimers. 相似文献
40.