Life on sand dunes from lichens point of view – effect of microclimate and seasonality on activity of terricolous lichen communities

Terricolous lichen communities are widely distributed in the Kiskunság Region, however we have limited information about the photosynthetic activity of the species living in different microhabitats. In consequence of the dominant wind direction, sand dunes of this region have mainly North-East (NE) and South-West (SW) exposure. These more humid (NE) and more arid (SW) slopes ensure diverse microhabitats for terricolous lichen species with different environmental requirements. To ascertain the effect of microclimate and seasonal weather conditions beside chlorophyll fluorescence measurements and photosynthetic pigment composition analysis, two HOBO micrometeorological stations (with Tsoil, WCsoil, Tair, RH% and PAR sensors) were placed on NE and SW facing slopes of a sand dune near Bugacpuszta. During the three year continuous data collection we got an inside view of lichen’s everyday living conditions. The most considerable differences between the two microhabitat types were in Tsoil, in irradiation and in relative humidity. In greater detail, degree and trend of variation in parameters changed during the day, and showed characteristic seasonality. We observed significant differences in all micrometeorological parameters between seasons during the years. In long-term on SW facing slope because of averagely higher air temperature (0,2 °C) and lower air humidity (0,5%) the vapour pressure deficit is higher (0,2 kPa) than that of on NE facing slopes. The higher incoming irradiation on SW side causes higher soil temperature, and lower soil water content. PAR, WCsoil and Tsoil showed significant difference between microhabitats in every season. In summer probably the short active periods on both types of microhabitats cause smaller difference in Fv/Fm, meanwhile in spring the small difference between more arid and more humid microhabitats can explain with the most beneficial environmental conditions during the year

Comparison of human hepatoma HepaRG cells with human and rat hepatocytes in uptake transport assays in order to predict drug induced hepatotoxicity

Human hepatocytes are the gold standard for toxicological studies but they have several drawbacks, like scarce availability, high inter-individual variability, a short lifetime, which limits their applicability. The aim of our investigations was to determine, whether HepaRG cells could replace human hepatocytes in uptake experiments for toxicity studies. HepaRG is a hepatoma cell line with most hepatic functions, including a considerable expression of uptake transporters in contrast to other hepatic immortalized cell lines. We compared the effect of cholestatic drugs (bosentan, cyclosporinA, troglitazone,) and bromosulfophthalein on the uptake of taurocholate and estrone-3-sulfate in human and rat hepatocytes and HepaRG cells. The substrate uptake was significantly slower in HepaRG cells than in human hepatocytes, still, in the presence of drugs we observed a concentration dependent decrease in uptake. In all cell types, the culture time had a significant impact not only on the uptake process but on the inhibitory effect of drugs too. The most significant drug effect was measured at 4 h after seeding. Our report is among the first concerning interactions of the uptake transporters in the HepaRG, at the functional level. Results of the present study clearly show that concerning the inhibition of taurocholate uptake by cholestatic drugs, HepaRG cells are closer to human hepatocytes than rat hepatocytes. In conclusion, we demonstrated that HepaRG cells provide a suitable tool for hepatic uptake studies

Cosmology with Gamma-Ray Bursts Using k-correction

In the case of Gamma-Ray Bursts with measured redshift, we can calculate the k-correction to get the fluence and energy that were actually produced in the comoving system of the GRB. To achieve this we have to use well-fitted parameters of a GRB spectrum, available in the GCN database. The output of the calculations is the comoving isotropic energy E_iso, but this is not the endpoint: this data can be useful for estimating the {\Omega}M parameter of the Universe and for making a GRB Hubble diagram using Amati's relation.Comment: 4 pages, 6 figures. Presented as a talk on the conference '7th INTEGRAL/BART Workshop 14 -18 April 2010, Karlovy Vary, Czech Republic'. Published in Acta Polytechnic