Получение и исследование магнитно-контрастных препаратов для МРТ

Целью данной работы является исследование полученного магнитно-контрастный препарата GDOF-Mn-DTPA. Определить Время релаксации для различных концентраций, выяснить минимальную контрастную дозу, провести исследование на влияние зависимости накопления препарата в печени от органической части, сравнить препарат с уже используемым аналогом.The aim of this work is to study the obtained magnetic contrast preparation GDOF-Mn-DTPA. Determine the relaxation time for various concentrations, find out the minimum contrast dose, conduct a study on the effect of the dependence of the drug accumulation in the liver on the organic part, compare the drug with the analogue already used

Entwicklung und Anwendung zeitaufgelöster Fourier-Transform-Infrarot-spektroskopischer Sekundärstrukturanalyse an ausgewählten Proteinen

Sekundärstrukturen von Proteinen wurden mit einer weiterentwickelten Zerlegung der Amid-I-Bande ihres IR-Extinktionsspektrums analysiert. Mit diesem Ansatz wurde die reduktionsinduzierte Umfaltungsreaktion des rekombinanten Volllängen-Prion Proteins analysiert. Ferner wurde die Sekundärstrukturzusammensetzung des nativ glykosylierten, membrangebundenen Proteins bestimmt. Die Struktur $\textit {de novo}$ synthetisierter, Membranfusion beschleunigender Peptide wurde in einer Polaritätstritration und in Lipidmembranen analysiert. Es gelang die erstmalige Charakterisierung der Sekundärstruktur des $\beta_{2}$-adrenergen Rezeptors, eines GPCRs. Eine enzymatische Spaltung des oberflächenimmobilisierten Proteins gelang spezifisch an der vorgesehenen Schnittstelle. Ergänzend wurden zwei weitere Proteine, der chloroplastidäre Signalerkennungspartikel cpSRP54 und das peroxisomale Importprotein Pex18p, mit der verfeinerten Bandenzerlegung auf Strukturänderungen durch Mutation bzw. durch Lipidkontakt analysiert

Mechanism of scrapie prion precipitation with phosphotungstate anions.

The phosphotungstate anion (PTA) is widely used to facilitate the precipitation of disease-causing prion protein (PrP(Sc)) from infected tissue for applications in structural studies and diagnostic approaches. However, the mechanism of this precipitation is not understood. In order to elucidate the nature of the PTA interaction with PrP(Sc) under physiological conditions, solutions of PTA were characterized by NMR spectroscopy at varying pH. At neutral pH, the parent [PW12O40](3-) ion decomposes to give a lacunary [PW11O39](7-) (PW11) complex and a single orthotungstate anion [WO4](2-) (WO4). To measure the efficacy of each component of PTA, increasing concentrations of PW11, WO4, and mixtures thereof were used to precipitate PrP(Sc) from brain homogenates of scrapie prion-infected mice. The amount of PrP(Sc) isolated, quantified by ELISA and immunoblotting, revealed that both PW11 and WO4 contribute to PrP(Sc) precipitation. Incubation with sarkosyl, PTA, or individual components of PTA resulted in separation of higher-density PrP aggregates from the neuronal lipid monosialotetrahexosylganglioside (GM1), as observed by sucrose gradient centrifugation. These experiments revealed that yield and purity of PrP(Sc) were greater with polyoxometalates (POMs), which substantially supported the separation of lipids from PrP(Sc) in the samples. Interaction of POMs and sarkosyl with brain homogenates promoted the formation of fibrillar PrP(Sc) aggregates prior to centrifugation, likely through the separation of lipids like GM1 from PrP(Sc). We propose that this separation of lipids from PrP is a major factor governing the facile precipitation of PrP(Sc) by PTA from tissue and might be optimized further for the detection of prions

Comparison of the molecular properties of retinitis pigmentosa P23H and N15S amino acid replacements in rhodopsin

<div><p>Mutations in the <i>RHO</i> gene encoding for the visual pigment protein, rhodopsin, are among the most common cause of autosomal dominant retinitis pigmentosa (ADRP). Previous studies of ADRP mutations in different domains of rhodopsin have indicated that changes that lead to more instability in rhodopsin structure are responsible for more severe disease in patients. Here, we further test this hypothesis by comparing side-by-side and therefore quantitatively two <i>RHO</i> mutations, N15S and P23H, both located in the N-terminal intradiscal domain. The <i>in vitro</i> biochemical properties of these two rhodopsin proteins, expressed in stably transfected tetracycline-inducible HEK293S cells, their UV-visible absorption, their Fourier transform infrared, circular dichroism and Metarhodopsin II fluorescence spectroscopy properties were characterized. As compared to the severely impaired P23H molecular function, N15S is only slightly defective in structure and stability. We propose that the molecular basis for these structural differences lies in the greater distance of the N15 residue as compared to P23 with respect to the predicted rhodopsin folding core. As described previously for WT rhodopsin, addition of the cytoplasmic allosteric modulator chlorin e6 stabilizes especially the P23H protein, suggesting that chlorin e6 may be generally beneficial in the rescue of those ADRP rhodopsin proteins whose stability is affected by amino acid replacement.</p></div

Correction: Comparison of the molecular properties of retinitis pigmentosa P23H and N15S amino acid replacements in rhodopsin.

[This corrects the article DOI: 10.1371/journal.pone.0214639.]

Amyloid-β-Secondary Structure Distribution in Cerebrospinal Fluid and Blood Measured by an Immuno-Infrared-Sensor: A Biomarker Candidate for Alzheimer’s Disease

The misfolding of the Amyloid-beta (Aβ) peptide into β-sheet enriched conformations was proposed as an early event in Alzheimer’s Disease (AD). Here, the Aβ peptide secondary structure distribution in cerebrospinal fluid (CSF) and blood plasma of 141 patients was measured with an immuno-infrared-sensor. The sensor detected the amide I band, which reflects the overall secondary structure distribution of all Aβ peptides extracted from the body fluid. We observed a significant downshift of the amide I band frequency of Aβ peptides in Dementia Alzheimer type (DAT) patients, which indicated an overall shift to β-sheet. The secondary structure distribution of all Aβ peptides provides a better marker for DAT detection than a single Aβ misfold or the concentration of a specific oligomer. The discrimination between DAT and disease control patients according to the amide I frequency was in excellent agreement with the clinical diagnosis (accuracy 90% for CSF and 84% for blood). The amide I band maximum above or below the decisive marker frequency appears as a novel spectral biomarker candidate of AD. Additionally, a preliminary proof-of-concept study indicated an amide I band shift below the marker band already in patients with mild cognitive impairment due to AD. The presented immuno-IR-sensor method represents a promising, simple, robust, and label-free diagnostic tool for CSF and blood analysis