Universitatsstr 31

Regensburg, Germany

Universitatsstr 31

Regensburg, Germany
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Wiesneth S.,Universitatsstr 31 | Petereit F.,Institute of Pharmaceutical Biology and Phytochemistry IPBP | Jurgenliemk G.,Universitatsstr 31
Molecules | Year: 2015

In the present study, a qualitative analysis of proanthocyanidins (PAs) from an aqueous-methanolic extract of Salix daphnoides VILL. bark is described. Procyanidin B1 (1), B2 (2), B3 (3), B4 (4), C1 (5), epicatechin-(4β→8)-epicatechin-(4β→8)-catechin (6) and epicatechin-(4β→8)-epicatechin-(4β→8)-epicatechin-(4β→8)-catechin (7) have been isolated by a combination of different chromatographic separations on Sephadex® LH-20-, MCI®-, Diol-and RP-18-phases. Mass spectrometry, 1D- and 2D-NMR, circular dichroism and polarimetry were used for their structure elucidation and verification by comparison with the literature. Additionally, two fractions of very polar flavan-3-ols were compared: "regular" polymeric PAs received at the very end of the Sephadex® LH-20 chromatography showing no mobility on silica TLC and "unusual" PAs with the same RF-value but already eluting together with flavonoids in the Sephadex® LH-20 system. These "unusual" PAs were subsequently enriched by centrifugal partition chromatography (CPC). C-NMR, polarimetry, thiolysis, acid hydrolysis and phloroglucinol degradation were used to characterize both fractions. Differences in the composition of different flavan-3-ol units and the middle chain length were observed. © 2015 by the authors.


Kovalska V.,NASU Institute of Molecular Biology and Genetics | Chernii S.,NASU Institute of Molecular Biology and Genetics | Losytskyy M.,NASU Institute of Molecular Biology and Genetics | Dovbii Y.,Vernadskii Institute of General and Inorganic Chemistry | And 5 more authors.
Dyes and Pigments | Year: 2016

The series of the β-ketoenoles (2E,5Z,7E,9E)-2-(alkylamino)-6-hydroxy-10-phenyldeca-2,5,7,9-tetraen-4-ones with variation of the alkylamino tail groups was synthesized and studied as potential probes for the sensing of protein insoluble aggregates - amyloid fibrils. Depending on the structure of the alkylamino group, the dyes could increase their fluorescence intensity in the dozens of times in the presence of insulin fibrils. The compound with a 2-hydroxyethylamino substituent demonstrates the highest fluorescence response (up to 60 times) and good range of insulin fibril detection (1-50 μg/ml). In complexes with fibrils, the dyes possess fluorescence quantum yield values up to 15% and binding constant values of about 2 × 105 M-1. The excitation and emission maxima of β-ketoenoles are located in the range 407-427 nm and 500-554 nm correspondingly. These compounds are weakly fluorescent when free and slightly sensitive to the native proteins insulin and bovine serum albumin. Thus β-ketoenoles are considered as prospective molecules for the fluorescent detection of amyloid aggregates of proteins. © 2016 Elsevier Ltd. All rights reserved.


Bohm C.,Universitatsstr 31 | Lauf W.,Universitatsstr 31
Computational Methods and Function Theory | Year: 2014

We give a generalization of the Komatu–Loewner equation to multiple slits. Therefore, we consider an n-connected circular slit disk Ω as our initial domain minus m ∈ N disjoint, simple and continuous curves that grow from the outer boundary ∂D of Ω into the interior. Consequently, we get a decreasing family (Formula Presented.) of domains with Ω0=Ω. We will prove that the corresponding Riemann mapping functions gt from Ωt onto a circular slit disk, which are normalized by gt(0)=0 and gt'(0)>0, satisfy a Loewner equation known as the Komatu–Loewner equation. © 2014, Springer-Verlag Berlin Heidelberg.


PubMed | Universitatsstr 31 and Institute of Pharmaceutical Biology and Phytochemistry IPBP
Type: Journal Article | Journal: Molecules (Basel, Switzerland) | Year: 2015

In the present study, a qualitative analysis of proanthocyanidins (PAs) from an aqueous-methanolic extract of Salix daphnoides VILL. bark is described. Procyanidin B1 (1), B2 (2), B3 (3), B4 (4), C1 (5), epicatechin-(48)-epicatechin-(48)-catechin (6) and epicatechin-(48)-epicatechin-(48)-epicatechin-(48)-catechin (7) have been isolated by a combination of different chromatographic separations on Sephadex LH-20-, MCI-, Diol-and RP-18-phases. Mass spectrometry, 1D- and 2D-NMR, circular dichroism and polarimetry were used for their structure elucidation and verification by comparison with the literature. Additionally, two fractions of very polar flavan-3-ols were compared: regular polymeric PAs received at the very end of the Sephadex LH-20 chromatography showing no mobility on silica TLC and unusual PAs with the same RF-value but already eluting together with flavonoids in the Sephadex LH-20 system. These unusual PAs were subsequently enriched by centrifugal partition chromatography (CPC). 13C-NMR, polarimetry, thiolysis, acid hydrolysis and phloroglucinol degradation were used to characterize both fractions. Differences in the composition of different flavan-3-ol units and the middle chain length were observed.


In all eukaryotes, a specialized enzyme, RNA polymerase I (Pol I), is dedicated to transcribe the 35S rRNA gene from a multicopy gene cluster, the ribosomal DNA (rDNA). In certain Saccharomyces cerevisiae mutants, 35S rRNA genes can be transcribed by RNA polymerase II (Pol II). In these mutants, rDNA silencing of Pol II transcription is impaired. It has been speculated that upstream activating factor (UAF), which binds to a specific DNA element within the Pol I promoter, plays a crucial role in forming chromatin structures responsible for polymerase specificity and silencing at the rDNA locus. We therefore performed an in-depth analysis of chromatin structure and composition in different mutant backgrounds. We demonstrate that chromatin architecture of the entire Pol I-transcribed region is substantially altered in the absence of UAF, allowing RNA polymerases II and III to access DNA elements flanking a Pol promoter-proximal Reb1 binding site. Furthermore, lack of UAF leads to the loss of Sir2 from rDNA, correlating with impaired Pol II silencing. This analysis of rDNA chromatin provides a molecular basis, explaining many phenotypes observed in previous genetic analyses.

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