On the Ca2 + binding and conformational change in EF-hand domains: Experimental evidence of Ca2 +-saturated intermediates of N-domain of calmodulin

Double mutation of Q41L and K75I in the N-domain of calmodulin (N-Cam) stabilizes the closed form of N-Cam such that binding of Ca2 + in solution no longer triggers a conformational change to the open form, and its Ca2 + binding affinity decreases dramatically. To further investigate the solvation effects on the structure, Ca2 + binding affinity and conformational dynamics of this N-Cam double mutant in the Ca2 + saturated state, we solved its X-ray structure. Surprisingly, the structure revealed an open conformation of the domain which contradicts its closed conformation in solution. Here we provide evidence that crystallization conditions were responsible for this Ca2 +-saturated domain open conformation in the crystal. Importantly, we demonstrate that the presence of the crystallization co-precipitant and alcohols were able to induce a progressive opening of the closed form of this domain, in Ca2 + saturated state, in solution. However, in the Ca2 + depleted state, addition of alcohols was unable to induce any opening of this domain in solution. In addition, in the Ca2 + saturated state, the molecular dynamics simulations show that while N-Cam can populate the open and closed conformation, the N-Cam double mutant exclusively populates the closed conformation. Our results provide experimental evidence of intermediate conformations of Ca2 +-saturated N-Cam in solution. We propose that conformational change of Ca2 + sensor EF-hand domains depends on solvation energetics, Ca2 + binding to promote the full open form, Ca2 + depleted state conformational dynamics, and the chemical properties of the molecules nearby key residues such as those at positions 41 and 75 in N-Cam

Determinants of the circadian blood pressure pattern in hospitalized hypertensive patients

Background. Non-dipping hypertension might be associated with increased cardiovascular risk and multiple diseases. The aim of our study was to assess if there are parameters identified in 24-hour ECG-Holter monitoring (ECG-Holter), transthoracic echocardiography (TTE), ECG parameters or laboratory data that allow prediction of circadian blood pressure profile (CBPP). Material and methods. One hundred and three consecutive patients (male: 50.5%), who underwent 24-hour ambulatory BP measurement and ECG-Holter simultaneously were analyzed. We divided patients into 3 groups: dipping was defined as 10–20% (28.2%), non-dipping as < 10% (50.5%) fall in nocturnal BP and reverse-dipping as higher nocturnal than diurnal BP (21.4%). Additionally, we performed TTE and laboratory check-up in all patients. We built multivariable models for nocturnal fall in systolic BP (SBP) and CBPP. Results. Multivariable model based on clinical factors was: nocturnal fall in SBP (%) = [13.28 – 0.11 × age – 8.33 × (dilated cardiomyopathy) – 5.95 × PAD – 6.02 × a-adrenolytic]. Multivariable model based on laboratory, echocardiographic and electrocardiographic parameters was: nocturnal fall in SBP (%) = [–27.28 + 1.47 × hemoglobin – 0.14 × CK-MB + 0.14 × maximal heart rate]. Multivariable model for CBPP based on clinical factors included use of beta- or alpha-adrenolytics or torasemide. Conclusions. We proved that nocturnal fall in SBP and CBPP could be predicted based on ECG-Holter parameters, laboratory data and TTE results, as well as based on detailed medical history. These findings may have implications on care of patients with hypertension

Wady zastawkowe serca i różne profile dobowe ciśnienia tętniczego

Introduction. Valvular heart diseases (VHD) increase the risk of cardiovascular morbidity and mortality. Little is known about the correlation between circadian blood pressure profile (CBPP) and VHD. The study aimed to clarify the association between CBPP and VHD prevalence. Material and methods. 103 consecutive patients (male: 50.5%), who underwent 24-hour ambulatory blood pressure measurement (ABPM) and Holter electrocardiography simultaneously were analysed. Patients were divided into 3 groups: dipping was defined as 10–20% (28.2%), non-dipping as < 10% (50.5%) fall in nocturnal blood pressure (BP) and reverse-dipping as higher nocturnal than diurnal BP (21.4%). VHD was assessed by transthoracic echocardiography and described as mild, moderate or severe regurgitation or stenosis accordingly. Further, the severity of VHD, nocturnal fall pattern and ABPM features in all groups were compared. Results. The authors found no statistically significant association between severity of VHD and dipping status. The presented study showed some correlations between VHD severity and different ABPM parameters. Conclusions. Though severity of VHD did not influence dipping status obtained by ABPM, there were associations between VHD and ABPM outcomes. Further studies are needed.Wstęp. Wady zastawkowe serca (VHD) zwiększają ryzyko zachorowań i zgonów z przyczyn sercowo-naczyniowych. Niewiele wiadomo na temat zależności między profilem dobowym ciśnienia tętniczego (CBPP) a VHD. Celem tej pracy było wyjaśnienie związku między CBPP a VHD. Materiał i meody. Do badania włączono 103 kolejnych pacjentów (mężczyźni 50,5%), u których równocześnie wykonano całodobowy pomiar ciśnienia tętniczego (ABPM) i 24-godzinny zapis elektrokardiograficzny metodą Holtera. Podzielono ich na trzy grupy: dippers — zdefiniowanych jako osoby z ciśnieniem tętniczym (BP) w nocy o 10–20% niższym niż w ciągu dnia (28,2%), non-dippers — osoby ze spadkiem BP w nocy mniejszym niż 10% (50,5%), reverse-dippers — osoby z wyższymi wartościami BP w nocy niż w ciągu dnia (21,4%). Metodą echokardiografii przezklatkowej oceniano VHD jako małą, umiarkowaną lub ciężką. Następnie porównywano ciężkość VHD, CBPP i dane z ABPM we wszystkich grupach. Wyniki. Nie znaleziono istotnej statystycznie zależności między cięż kością VHD a CBPP. Zaobserwowano korelację między ciężkością VHD a niektórymi parametrami ocenianymi w trakcie ABPM. Wnioski. Choć ciężkość VHD nie wpływała na CBPP, to istnieją zależności między wynikami VHD i ABPM. Konieczne są dalsze badania

POLISH TOWNS AND THE CHANGES IN THEIR AREAS AND POPULATION DENSITIES

DOI: 10.2478 Available on-line at: http://www.bulletinofgeography.umk.pl http://versita.com/bgssThis article presents the spatial and population density changes in Polish towns in the years 1960–2003. The assumed time frame allowed identifying area changes for a complete set of towns in different socio-economic conditions: the period of intense industrialisation, the economic crisis of the 1980s, the period of economic transition and finally in the years of a market economy. The investigation revealed that the trend shown by changes and the size of a town as measured by the number of its population are distinctly interrelated. It also demonstrated a much stronger dynamics of changes in the first subperiod, i.e. years 1960–1985, followed by a phase of relative stabilization (compared with the previous period) after the year 1980 (mainly of the spatial changes). Moreover, change intensity and change trends observed for the urban areas and population densities vary considerably in terms of space

The Voltage-Dependent Sodium Channel Family.

In neurones and other electrically excitable tissues, voltage-dependent sodium (Nav) channels play an essential role in initiating and propagating the action potential. High-resolution structures of sodium channels have revealed new details concerning these macromolecules that provide insights into their ion-specificity and the conformational changes they undergo during the action potential. Nav channels typically exist in vivo as multicomponent macromolecular assemblies, containing auxiliary proteins that modulate channel gating and trafficking. The properties of some of these auxiliary proteins raise the possibility that Nav channels may exist as functionally coupled complexes. The close similarity between different Nav channel subtypes has frustrated attempts to develop isoform-specific inhibitors. However, the combination of new structural insights, together with antibody-based reagents and site-directed mutagenesis of protein-based toxin inhibitors, raises the possibility of higher target specificities than previously possible. Such reagents may form the basis for a new generation of Nav channel drugs

Spectroscopic Studies of Intramolecular Proton Transfer in 2-(4-Fluorophenylamino)-5-(2,4-Dihydroxybenzeno)-1,3,4-Thiadiazole

Spectroscopic studies of the biologically active compound 2-(4-fluorophenylamino)-5-(2,4-dihydroxybenzeno)-1,3,4-thiadiazole (FABT), have been performed. Absorption studies in the UV-Vis region for FABT in polar solvents, like water or ethanol, exhibit the domination of the enol form over its keto counterpart, with a broad absorption band centered around 340 nm. In non-polar solvents such as n-heptane or heavier alkanes the 340 nm absorption band disappears and an increase of the band related to the keto form (approximately 270 nm) is observed. Fluorescence spectra (with 270 nm and 340 nm excitation energies used) show a similar dependence: for FABT in 2-propanol a peak at about 400 nm dominates over that at 330 nm while in n-heptane this relation is reversed. The solvent dependent equilibrium between the keto and enol forms is further confirmed by FTIR and Raman spectroscopies. As can be expected, this equilibrium also shows some temperature dependences. We note that the changes between the two tautomeric forms of FABT are not related to the permanent dipole moment of the solvent but rather to its dipole polarizability

Analysis of NPM1 splice variants reveals differential expression patterns of prognostic value in acute myeloid leukemia

Mutations of the nucleophosmin-1 (NPM1) gene in cytogenetically normal (CN) acute myeloid leukemia (AML) identify a group of patients with more favorable prognosis. NPM1 encodes three main alternatively spliced isoforms R1(B23.1), R2(B23.2), and R3(B23.3). The expression of splice variants R1, R2 and R3 were higher in AML patients compared to normal cells of healthy volunteers (HVs), although RNA-seq analysis revealed enhanced R2 expression also in less differentiated cells of HVs as well as in AML cells. The variant R2, which lacks exons 11 and 12 coding for the nucleolar localization domain, might behave similar to the mutant form of NPM1 (NPM1mut). In accordance, in CN-AML high R2 expression was associated with favorable impact on outcome. Moreover, functional studies showed nucleolar localization of the eGFP-NPM1 wildtype and cytoplasmic localization of the eGFP-NPM1 mut protein. While the eGFP-NPM1 R2 splice variant localized predominantly in the nucleoplasm, we also could detect cytoplasmic expression for the R2 variant. These results support a unique biological consequence of R2 overexpression and in part explain our clinical observation, where that high R2 variant expression was associated with a better prognosis in CN-AML patients

Novel catalytically active pd/Ru bimetallic nanoparticles synthesized by Bacillus benzeovorans

This work was supported by a UK Commonwealth scholarship to JBO. BK was supported by the Petroleum Technology Development Funds (PTDF) of Nigeria. The project was funded by NERC grant NE/L014076/1 to LEM. The Science City Photoemission Facility used in this research was funded through the Science Cities Advanced Materials Project 1: Creating and Characterizing Next Generation of Advanced Materials with support from AWM and ERDF funds. The microscopy work was conducted in the “Laboratorio de Microscopias Avanzadas” at “Instituto de Nanociencia de Aragon - Universidad de Zaragoza” Spain. The authors acknowledge the LMA-INA for offering access to their instruments and expertise.Bacillus benzeovorans assisted and supported growth of ruthenium (bio-Ru) and palladium/ruthenium (bio-Pd@Ru) core@shell nanoparticles (NPs) as bio-derived catalysts. Characterization of the bio-NPs using various electron microscopy techniques and high-angle annular dark field (HAADF) analysis confirmed two NP populations (1–2 nm and 5–8 nm), with core@shells in the latter. The Pd/Ru NP lattice fringes, 0.231 nm, corresponded to the (110) plane of RuO2. While surface characterization using X-ray photoelectron spectroscopy (XPS) showed the presence of Pd(0), Pd(II), Ru(III) and Ru(VI), X-ray absorption (XAS) studies of the bulk material confirmed the Pd speciation (Pd(0) and Pd(II)- corresponding to PdO), and identified Ru as Ru(III) and Ru(IV). The absence of Ru–Ru or Ru–Pd peaks indicated Ru only exists in oxide forms (RuO2 and RuOH), which are surface-localized. X ray diffraction (XRD) patterns did not identify Pd-Ru alloying. Preliminary catalytic studies explored the conversion of 5-hydroxymethyl furfural (5-HMF) to the fuel precursor 2,5-dimethyl furan (2,5-DMF). Both high-loading (9.7 wt.% Pd, 6 wt.% Ru) and low-loading (2.4 wt.% Pd, 2 wt.% Ru) bio-derived catalysts demonstrated high conversion efficiencies (~95%) and selectivity of ~63% (~20% better than bio-Ru NPs) and 58%, respectively. These materials show promising future scope as efficient low-cost biofuel catalysts.Funded by NERC grant NE/L014076/

Programmed Death-1 and Its Ligand Are Novel Immunotolerant Molecules Expressed on Leukemic B Cells in Chronic Lymphocytic Leukemia

Programmed death-1 (PD-1) is an immunoreceptor predominantly expressed on exhausted T cells, which through an interaction with its ligand (PD-L1), controls peripheral tolerance by limiting effector functions of T lymphocytes. qRT-PCR for PD-1, PD-L1 and their splicing forms as well as flow cytometric assessment of surface expression was performed in a cohort of 58 chronic lymphocytic leukemia (CLL) patients. In functional studies, we assessed the influence of the proliferative response of leukemic B-cells induced by IL-4 and CD40L on PD-1 transcripts and expression on the protein level. The median level of PD-1, but not PD-L1, transcripts in CLL patients was higher in comparison to healthy volunteers (HVs, n = 43, p = 0.0057). We confirmed the presence of PD-1 and PD-L1 on the CLL cell surface, and found the expression of PD-1, but not PD-L1, to be higher among CLL patients in comparison to HVs (47.2% vs. 14.8%, p<0.0001). The Kaplan-Meier curves for the time to progression and overall survival in groups with high and low surface expression of PD-1 and PD-L1 revealed no prognostic value in CLL patients. After stimulation with IL-4 and CD40L, protein expression of PD-1 was significantly increased in samples that responded and up-regulated CD38. PD-1, which is aberrantly expressed both at mRNA and cell surface levels in CLL cells might represent a novel immunotolerant molecule involved in the pathomechanism of the disease, and could provide a novel target for future therapies