The material of Scopula spp. specimens (n = 1181) in the Hungarian Natural History Museum is revised in the light of recent publications. The museum hosts vouchers of three species from the ...white-coloured taxa of the “ornata speciesgroup” from the Carpathian Basin and six species from the Palaearctic Region. A historical specimen of S. orientalis, undoubtedly collected in the Carpathian Basin, was found amongst Palaearctic material. This is the first record of this species from the area and its most inland occurrence in Europe. A key to the identification of the three species recorded from the Carpathian Basin is given. With eight figures.
We constructed a “temperature-jump/stopped-flow” apparatus that allows us to study fast enzyme reactions at extremely high temperatures. This apparatus is a redesigned stopped-flow which is capable ...of mixing the reactants on a submillisecond timescale concomitant with a temperature-jump even as large as 60°C. We show that enzyme reactions that are faster than the denaturation process can be investigated above denaturation temperatures. In addition, the temperature-jump/stopped-flow enables us to investigate at physiological temperature the mechanisms of many human enzymes, which was impossible until now because of their heat instability. Furthermore, this technique is extremely useful in studying the progress of heat-induced protein unfolding. The temperature-jump/stopped-flow method combined with the application of structure-specific fluorescence signals provides novel opportunities to study the stability of certain regions of enzymes and identify the unfolding-initiating regions of proteins. The temperature-jump/stopped-flow technique may become a breakthrough in exploring new features of enzymes and the mechanism of unfolding processes.
ABCG2, a member of the ATP-binding cassette transporters has been identified as a protective pump against endogenous and exogenous
toxic agents. ABCG2 was shown to be expressed at high levels in stem ...cells and variably regulated during cell differentiation.
Here we demonstrate that functional ABCG2 is expressed in human monocyte-derived dendritic cells by the activation of a nuclear
hormone receptor, PPARγ. We identified and characterized a 150-base pair long conserved enhancer region, containing three
functional PPAR response elements (PPARE), upstream of the human ABCG2 gene. We confirmed the binding of the PPARγ·RXR heterodimer to this enhancer region, suggesting that PPARγ directly regulates
the transcription of ABCG2. Consistent with these results, elevated expression of ABCG2 mRNA was coupled to enhanced protein
production, resulting in increased xenobiotic extrusion capacity via ABCG2 in PPARγ-activated cells. Furthermore PPARγ instructed
dendritic cells showed increased Hoechst dye extrusion and resistance to mitoxantrone. Collectively, these results uncovered
a mechanism by which up-regulation of functional ABCG2 expression can be achieved via exogenous or endogenous activation of
the lipid-activated transcription factor, PPARγ. The increased expression of the promiscuous ABCG2 transporter can significantly
modify the xenobiotic and drug resistance of human myeloid dendritic cells.
PDF
