72 research outputs found
Про конституційно-правові засади національного суверенітету в Україні
Розглядаються характеристики народу та нації як суб’єктів конституційно-правових відносин, зв’язок етнічного і політичного чинників у змісті національного суверенітету.Рассматриваются характеристики народа и нации как субъектов конституционно-правовых отношений, связь этнического и политического в содержании национального суверенитета.Describe the nations and the peoples as subjects of constitutionals law relatios, the connection between ethnos and political in content of national sovereignty
Effect of slow freezing versus vitrification on the recovery of mouse embryonic stem cells
The purpose of this study was to cryopreserve mouse embryonic stem (ES) cells R1 line and determine cell viability, morphology, the number of colonies, and the Alkaline Phosphatase (AP) activity. In addition, the expression of transcription factors such as the stage-specific antigen (SSEA-1) and Octamer-4 (Oct-4) were evaluated before and after cryopreservation. The effects of two methods of cryopreservation, slow freezing and vitrification, were studied. The ES cells were cryopreserved either as single cells or as clumps. The viability of a single cell after slow freezing was 88%, but after vitrification no single cell was recovered. Surviving clumps after slow freezing quickly recovered and exhibited a morphology indistinguishable from noncryopreserved cells. After vitrification, 2 weeks of culture were required for the cells in clumps to proliferate enough for subculturing. Analysis of cloning efficiency and the colonies morphology were based on a mouse colony rating scale and their characteristic. The colonies from the slow-freezing group were compared to colonies from the control group, which were the cells before cryopreservation, and they showed the same cloning efficiency and morphology. The colonies from the vitrified group were compared to the colonies from the control group, and they showed differences in cloning efficiency on the mouse colony rating scale A (<0.05) and C (<0.05) but they did not show differences in their morphology. The biggest clumps from both experimental groups showed a reduction of viability in the center area compared to the fresh ones. The survival rate of the clumps in the slow-freezing and rapid-thawing group was 75% and in the vitrified group 25%. The colonies from the control group and both experimental cryopreservation groups show the same activity of AP, and they were all positive for SSEA-1 and Oct-4. The conventional slow-freezing method of cryopreservation of single cells and clumps is reliable and effective for the cryopreservation of mouse R1 ES cells. Vitrification can be used for cryopreservation of these same cell clumps but with lower recovery using the conditions that we used. © Mary Ann Liebert, Inc
Two desmin gene mutations associated with myofibrillar myopathies in Polish families
10.1371/journal.pone.0115470PLoS ONE912e11547
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Cryo-EM structure of the native rhodopsin dimer in nanodiscs
Imaging of rod photoreceptor outer-segment disc membranes by atomic force microscopy and cryo-electron tomography has revealed that the visual pigment rhodopsin, a prototypical class A G protein?coupled receptor (GPCR), can organize as rows of dimers. GPCR dimerization and oligomerization offer possibilities for allosteric regulation of GPCR activity, but the detailed structures and mechanism remain elusive. In this investigation, we made use of the high rhodopsin density in the native disc membranes and of a bifunctional cross-linker that preserves the native rhodopsin arrangement by covalently tethering rhodopsins via Lys residue side chains. We purified cross-linked rhodopsin dimers and reconstituted them into nanodiscs for cryo-EM analysis. We present cryo-EM structures of the cross-linked rhodopsin dimer as well as a rhodopsin dimer reconstituted into nanodiscs from purified monomers. We demonstrate the presence of a preferential 2-fold symmetrical dimerization interface mediated by transmembrane helix 1 and the cytoplasmic helix 8 of rhodopsin. We confirmed this dimer interface by double electron?electron resonance measurements of spin-labeled rhodopsin. We propose that this interface and the arrangement of two protomers is a prerequisite for the formation of the observed rows of dimers. We anticipate that the approach outlined here could be extended to other GPCRs or membrane receptors to better understand specific receptor dimerization mechanisms
Photocyclic behavior of rhodopsin induced by an atypical isomerization mechanism
Vertebrate rhodopsin (Rh) contains 11-cis-retinal as a chromophore to convert light energy into visual signals. On absorption of light, 11-cis-retinal is isomerized to all-trans-retinal, constituting a one-way reaction that activates transducin (G(t)) followed by chromophore release. Here we report that bovine Rh, regenerated instead with a six-carbon-ring retinal chromophore featuring a C(11)=C(12) double bond locked in its cis conformation (Rh6mr), employs an atypical isomerization mechanism by converting 11-cis to an 11,13-dicis configuration for prolonged G(t) activation. Time-dependent UV-vis spectroscopy, HPLC, and molecular mechanics analyses revealed an atypical thermal reisomerization of the 11,13-dicis to the 11-cis configuration on a slow timescale, which enables Rh6mr to function in a photocyclic manner similar to that of microbial Rhs. With this photocyclic behavior, Rh6mr repeatedly recruits and activates G(t) in response to light stimuli, making it an excellent candidate for optogenetic tools based on retinal analog-bound vertebrate Rhs. Overall, these comprehensive structure–function studies unveil a unique photocyclic mechanism of Rh activation by an 11-cis–to–11,13-dicis isomerization
Haemostatic differences between SARS-CoV-2 PCR-positive and negative patients at the time of hospital admission.
Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is associated with thrombosis. We conducted a cohort study of consecutive patients, suspected of SARS-CoV-2 infection presented to the emergency department. We investigated haemostatic differences between SARS-CoV-2 PCR positive and negative patients, with dedicated coagulation analysis. The 519 included patients had a median age of 66 years, and 52.5% of the patients were male. Twenty-six percent of the patients were PCR-positive for SARS-CoV-2.PCR positive patients had increased levels of fibrinogen and (active) von Willebrand Factor (VWF) and decreased levels of protein C and α2-macroglobulin compared to the PCR negative patients. In addition, we found acquired activated protein C resistance in PCR positive patients. Furthermore, we found that elevated levels of factor VIII and VWF and decreased levels of ADAMTS-13 were associated with an increased incidence of thrombosis in PCR positive patients. In conclusion, we found that PCR positive patients had a pronounced prothrombotic phenotype, mainly due to an increase of endothelial activation upon admission to the hospital. These findings show that coagulation tests may be considered useful to discriminate severe cases of COVID-19 at risk for thrombosis
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