Protein binding to lipid-coated nanoparticles has been pursued quantitatively by using fluorescence correlation spectroscopy. The binding of three important plasma proteins to lipid-enwrapped quantum ...dots (QDs) shows very low affinity, with an apparent dissociation coefficient in the range of several hundred micromolar. Thus, the tendency to adsorb is orders of magnitude weaker than for QDs coated with dihydrolipoic acid.
Extremely low binding affinities of plasma proteins to MHPC lipid-enwrapped quantum dots have been revealed by fluorescence correlation spectroscopy measurements.
The expression of CTLA-4 (CD152) on the cell surface of B cells and its consequences for the humoral immune response in vivo are unknown. We investigated the expression of CTLA-4 mRNA and protein in ...B cells in T cell-independent or -dependent ways. B cells in the presence of Ag-stimulated Th2 cells expressed mRNA of CTLA-4 and up-regulated intracellular CTLA-4 protein. Using a liposome-enhanced staining technique, we show for the first time, that surface CTLA-4 protein is expressed by 11-15% of B cells in a T cell-dependent culture system. To dissect the role of CTLA-4 on B cells in vivo, we used bone marrow chimeric mice in which only B cells were CTLA-4 deficient. These mice showed that early B cell development and homeostasis is not influenced by CTLA-4 deficiency of B cells. Ag-specific responses after immunization of the chimeric mice revealed elevated levels of IgM Abs in mice deficient for B cell CTLA-4. We propose that CTLA-4 signals on B cells determine the early fate of B cells in thymus-dependent immune responses.
The Bicultural Phenomenon Schindler, Simon; Reinhard, Marc-André; Knab, Martin ...
Social psychology (Göttingen, Germany),
09/2016, Letnik:
47, Številka:
5
Journal Article
Recenzirano
Cross-cultural research has indicated that bicultural
individuals switch their behavioral patterns according to situational cultural
frames. Based on self-categorization theory and evidence that ...being prototypical
for an ingroup can increase ingroup identification, we investigated the idea
that when being prototypical for a specific culture, bicultural individuals
switch their cultural identification toward the culture for which they are
prototypical. According to previous findings, we additionally investigated the
moderating role of perceived cultural compatibility. In this study, we
manipulated cultural group prototypicality by giving immigrant Polish-German
participants test performance feedback. As hypothesized, participants either
showed increased identification with the German culture when the feedback
rendered them prototypically German, or with the Polish culture when the
feedback rendered them prototypically Polish. This effect was moderated by
perceived cultural compatibility. Implications for a self-enhancement motive are
discussed.
Current therapies for neurological disorders are based on traditional medication and electric stimulation. Here, we present an organic electronicbiomimetic neuron, with the capacity to precisely ...intervene with the underlying malfunctioning signalling pathway using endogenous substances. The fundamental function of neurons, defined as chemical-to-electrical-to-chemical signal transduction, is achieved by connecting enzyme-based amperometric biosensors and organic electronic ion pumps. Selective biosensors transduce chemical signals into an electric current, which regulates electrophoretic delivery of chemical substances without necessitating liquid flow. Biosensors detected neurotransmitters in physiologically relevant ranges of 5–80 µM, showing linear response above 20 µm with approx. 0.1 nA/µM slope. When exceeding defined threshold concentrations, biosensor output signals, connected via custom hardware/software, activated local or distant neurotransmitter delivery from the organic electronic ion pump. Changes of 20 µM glutamate or acetylcholinetriggered diffusive delivery of acetylcholine, which activated cells via receptor-mediated signalling. This was observed in real-time by single-cell ratiometric Ca2+ imaging. The results demonstrate the potential of the organic electronic biomimetic neuron in therapies involving long-range neuronal signalling by mimicking the function of projection neurons. Alternatively, conversion of glutamate-induced descending neuromuscular signals into acetylcholine-mediated muscular activation signals may be obtained, applicable for bridging injured sites and active prosthetics.
Photoreceptor noise sets an absolute limit for the accuracy of colour discrimination. We compared colour thresholds in the honeybee (
Apis mellifera) with this limit. Bees were trained to ...discriminate an achromatic stimulus from monochromatic lights of various wavelengths as a function of their intensity. Signal-to-noise ratios were measured by intracellular recordings in the three spectral types of photoreceptor cells. To model thresholds we assumed that discrimination was mediated by opponent mechanisms whose performance was limited by receptor noise. Most of the behavioural thresholds were close to those predicted from receptor signal-to-noise ratios, suggesting that colour discrimination in honeybees is affected by photoreceptor noise. Some of the thresholds were lower than this theoretical limit, which indicates summation of photoreceptor cell signals.
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