Overweight children : can parent education put a halt on this epidemic?

Scholarly project (M.S.)

Silver selective electrodes based on thioether functionalized calix[4]arenes as ionophores

Silver selective electrodes based on thioether functionalized calix[4]arenes 1 and 2 as ionophores were investigated. For both ionophores the selectivity coefficients (log kAg,M) were lower than −2.2 for Hg(II) and lower than −4.6 for other cations tested. The best results were obtained with membranes containing dithioether functionalized calix[4]arene (ionophore 2), potassium tetrakis(4-chlorophenyl) borate (KTpCIPB) and bis(1-butylpentyl)adipate (BBPA) as a plasticizer. The Ag(I)-response functions exhibited almost theoretical Nernstian slopes in the activity range 10−6–10−1M of silver ions.\ud \u

The rabies virus phosphoprotein P: a key regulator of innate immune responses

Interferons are the key cytokines of innate immunity and represent the first line of defense against invading viruses. By activating immediate antiviral mechanisms and stimulating the adaptive immune response, interferon signaling is decisive for the outcome of disease and virus clearance. The work presented in this thesis reveals a central role of the phosphoprotein P of rabies virus (Rhabdoviridae family), known as a polymerase cofactor, as an inhibitor of the host interferon system. Counter-mechanism to escape form recognition by the immune system were previously unknown for the neurotropic rabies virus, which is characterized by the highest case-fatality ratio. In my work I have shown that rabies virus (strain SAD L16) is able to prevent both the production IFN-alpha/beta and the effector functions of IFN-alpha/beta and IFN-gamma. The factor responsible is the viral phosphoprotein P. P interferes with transcriptional activation of IFN-alpha/beta by preventing phosphorylation of the essential transcription factors IRF3 and IRF7 by their kinases TBK1 and IKKepsilon. Unphosphorylated IRFs are unable to dimerize and fail to enter the nucleus. In addition, rabies virus P prevents IFN-mediated JAK/STAT signaling and the expression of IFN-stimulated genes which include a broad spectrum of antiviral and immune regulatory genes. The inhibition of JAK/STAT signaling by P involves a unique mechanism, namely, specific binding of the tyrosine-phosphorylated STAT1 and STAT2 isoforms and their retention in the cytoplasm. The inhibitory activities of RV P on IFN induction and signaling are independent functions, as shown by site-directed mutagenesis of P and identification of different short amino acid stretches required for either function. Importantly, the inhibitory activities of P were demonstrated in the context of recombinant viruses. Using reverse genetics, a rabies virus was constructed, in which P expression was “knocked down” by moving the P gene to a promoter-distal position of the genome (SAD deltaPLP). This virus caused efficient IFN-alpha/beta production in infected cells and upregulation of interferon stimulated genes. The IFN sensitivity of SAD deltaPLP was confirmed in cell culture and is now being studied in animal experiments including IFN receptor knock of mice, to verify the relevance of P functions in vivo. The described work contributes to the understanding of host responses to virus infections in general and of rabies virus pathogenicity in particular. In addition, viruses with modified IFN antagonists provide interesting opportunities for development of attenuated vaccines and vectors

Ein selbstassoziierender difunktioneller Rezeptor

Durch Komplexierung eines Na+ ‐Ions „einschalten”︁ läßt sich die Fähigkeit des Kationenrezeptors 1, eines Calixarens, Wasserstoffbrückenbindungen zwischen der Diamidopyridingruppe und einer komplementären Gruppe wie Thymin zu bilden. Ist diese ihrerseits an einen Anionenrezeptor (z.B. ein metalliertes Porphyrin) gebunden, erhält man einen nichtkovalent zusammengesetzten, difunktionellen Rezeptor, in dem Kation und Anion eines anorganischen Salzes wie NaSCN gleichzeitig komplexiert vorliegen

Effect of a high surface-to-volume ratio on fluorescence-based assays

In the work discussed in this paper, the effect of a high surface-to-volume ratio of a microfluidic detection cell on fluorescence quenching was studied. It was found that modification of the geometry of a microchannel can provide a wider linear range. This is a phenomenon which should be taken into consideration when microfluidic systems with fluorescence detection are developed. The dependence of the linear range for fluorescein on the surface-to-volume ratio was determined. Both fluorescence inner-filter effects and concentration self-quenching were taken into consideration. It was found that inner-filter effects have little effect on the extent of the linear range on the microscale. [Figure: see text

Inhibition of CDK8 mediator kinase suppresses estrogen dependent transcription and the growth of estrogen receptor positive breast cancer

Hormone therapy targeting estrogen receptor (ER) is the principal treatment for ER-positive breast cancers. However, many cancers develop resistance to hormone therapy while retaining ER expression. Identifying new druggable mediators of ER function can help to increase the efficacy of ER-targeting drugs. Cyclin-dependent kinase 8 (CDK8) is a Mediator complex-associated transcriptional regulator with oncogenic activities. Expression of CDK8, its paralog CDK19 and their binding partner Cyclin C are negative prognostic markers in breast cancer. Meta-analysis of transcriptome databases revealed an inverse correlation between CDK8 and ERalpha expression, suggesting that CDK8 could be functionally associated with ER. We have found that CDK8 inhibition by CDK8/19-selective small-molecule kinase inhibitors, by shRNA knockdown or by CRISPR/CAS9 knockout suppresses estrogen-induced transcription in ER-positive breast cancer cells; this effect was exerted downstream of ER. Estrogen addition stimulated the binding of CDK8 to the ER-responsive GREB1 gene promoter and CDK8/19 inhibition reduced estrogen-stimulated association of an elongation-competent phosphorylated form of RNA Polymerase II with GREB1. CDK8/19 inhibitors abrogated the mitogenic effect of estrogen on ER-positive cells and potentiated the growth-inhibitory effects of ER antagonist fulvestrant. Treatment of estrogen-deprived ER-positive breast cancer cells with CDK8/19 inhibitors strongly impeded the development of estrogen independence. In vivo treatment with a CDK8/19 inhibitor Senexin B suppressed tumor growth and augmented the effects of fulvestrant in ER-positive breast cancer xenografts. These results identify CDK8 as a novel downstream mediator of ER and suggest the utility of CDK8 inhibitors for ER-positive breast cancer therapy