Biophysical and functional characterization of hippocalcin mutants responsible for human dystonia

Dystonia is a neurological movement disorder that forces the body into twisting, repetitive movements or sometimes painful abnormal postures. With the advent of next-generation sequencing technologies, the homozygous mutations T71N and A190T in the neuronal calcium sensor (NCS) hippocalcin were identified as the genetic cause of primary isolated dystonia (DYT2 dystonia). However, the effect of these mutations on the physiological role of hippocalcin has not yet been elucidated. Using a multidisciplinary approach, we demonstrated that hippocalcin oligomerises in a calcium-dependent manner and binds to voltage-gated calcium channels. Mutations T71N and A190T in hippocalcin did not affect stability, calcium-binding affinity or translocation to cellular membranes (Ca2+/myristoyl switch). We obtained the first crystal structure of hippocalcin and alignment with other NCS proteins showed significant variability in the orientation of the C-terminal part of the molecule, the region expected to be important for target binding. We demonstrated that the disease-causing mutations did not affect the structure of the protein, however both mutants showed a defect in oligomerisation. In addition, we observed an increased calcium influx in KCl-depolarised cells expressing mutated hippocalcin, mostly driven by N-type voltage-gated calcium channels. Our data demonstrate that the dystonia-causing mutations strongly affect hippocalcin cellular functions which suggest a central role for perturbed calcium signalling in DYT2 dystonia

Диагностика привода високовольтных выключателей

Експериментально встановлено, що під час вимірювання часових характеристик вимикачів мікропроцесорними приладами осцилографування, можна додатково відслідковувати вплив опору кіл живлення котушок управління вимикачем. По формі кривої зміни струму через котушку можна отримати додаткову інформацію. про стан вимикача та його кіл живлення.The paper considers that it was experimentally established we can additionally determine the influence of resistanse of supplying circuits of controlling coils of the switcher while measuring of time characteristics of High Voltage Switchers by microprocessor oscilographing devices. We can obtain the additional information about the condition of the switcher and its supplying circuits according to the sharp of current change through the coil.В статье экспериментально установленно, что во время измерения временных характеристик выключателей микропроцессорными приборами осцилографирования, можно дополнительно отслеживать влияние сопротивления цепей питания катушек управления выключателем. По форме кривой изменения тока через катушку можно получить дополнительную информацию про состояние выключателя и его цепей питания

Superhump evolution of WZ Sge-type dwarf nova ASASSN-14cv at rebrightening stage

© 2016, Pleiades Publishing, Ltd.We report the results of observations of a WZ Sge-type dwarf nova ASASSN-14cv, acquired in 2014 and covering the end of a superoutburst and a rebrightening stage. We detected 8 rebrightenings of this star. Based on the light curve profiles of the rebrightenings, we conclude on the existence of both the “inside-out” and “outside-in” outbursts. During the entire course of the rebrightening stage, a brightness variability with the mean period of P = 0.d06042(8) was detected, which was identified as a superhump period during the stage B of the superoutburst. The character of the registered superhump evolution can be either described by a parabolic approximation with the negative Pdot = −1.1 × 10−5, or by an approximation with 2 linear areas with the corresponding periods of 0.d06074(3) and 0.d06046(9)

Dimeric structures of quinol-dependent nitric oxide reductases (qNORs) revealed by cryo–electron microscopy

Quinol-dependent nitric oxide reductases (qNORs) are membrane-integrated, iron-containing enzymes of the denitrification pathway, which catalyze the reduction of nitric oxide (NO) to the major ozone destroying gas nitrous oxide (N2O). Cryo–electron microscopy structures of active qNOR from Alcaligenes xylosoxidans and an activity-enhancing mutant have been determined to be at local resolutions of 3.7 and 3.2 Å, respectively. They unexpectedly reveal a dimeric conformation (also confirmed for qNOR from Neisseria meningitidis) and define the active-site configuration, with a clear water channel from the cytoplasm. Structure-based mutagenesis has identified key residues involved in proton transport and substrate delivery to the active site of qNORs. The proton supply direction differs from cytochrome c–dependent NOR (cNOR), where water molecules from the cytoplasm serve as a proton source similar to those from cytochrome c oxidase

The active form of quinol-dependent Nitric Oxide reductase (qNOR) from Neisseria meningitidis is a dimer

Neisseria meningitidis is carried by nearly a billion humans, causing developmental impairment and over 100 000 deaths a year. A quinol-dependent nitric oxide reductase (qNOR) plays a critical role in the survival of the bacterium in the human host. X-ray crystallographic analyses of qNOR, including that from N. meningitidis (NmqNOR) reported here at 3.15 Å resolution, show monomeric assemblies, despite the more active dimeric sample being used for crystallization. Cryo-electron microscopic analysis of the same chromatographic fraction of NmqNOR, however, revealed a dimeric assembly at 3.06 Å resolution. It is shown that zinc (which is used in crystallization) binding near the dimer-stabilizing TMII region contributes to the disruption of the dimer. A similar destabilization is observed in the monomeric (∼85 kDa) cryo-EM structure of a mutant (Glu494Ala) qNOR from the opportunistic pathogen Alcaligenes (Achromobacter) xylosoxidans, which primarily migrates as a monomer. The monomer–dimer transition of qNORs seen in the cryo-EM and crystallographic structures has wider implications for structural studies of multimeric membrane proteins. X-ray crystallographic and cryo-EM structural analyses have been performed on the same chromatographic fraction of NmqNOR to high resolution. This represents one of the first examples in which the two approaches have been used to reveal a monomeric assembly in crystallo and a dimeric assembly in vitrified cryo-EM grids. A number of factors have been identified that may trigger the destabilization of helices that are necessary to preserve the integrity of the dimer. These include zinc binding near the entry of the putative proton-transfer channel and the preservation of the conformational integrity of the active site. The mutation near the active site results in disruption of the active site, causing an additional destabilization of helices (TMIX and TMX) that flank the proton-transfer channel helices, creating an inert monomeric enzyme

Metabolic aspects of the relationship of asthma and obesity

Asthma and obesity are serious medical and social world problems, and their combined course is characterized by a decrease in the quality of life, an increase in the frequency and duration of hospitalization. The present review summarizes the current views on the mechanisms of formation of asthma phenotype combined with obesity, role of leptin and adiponectin imbalance in the development of systemic inflammation in obesity in the pathophysiology of asthma, it’s interrelations with metabolic syndrome. We present data that shows that syndrome is closely related not only to the debut of asthma, but also to a decrease in its control. Along with obesity, the role of other components of metabolic syndrome, in particular insulin resistance, as a predictor of asthma development is considered. Insulin resistance may be the most likely factor in the relationship between asthma and obesity, independent of other components of the metabolic syndrome. Insulin resistance associated with obesity can lead to disruption of nitric oxide synthesis. We reveal common mechanism of metabolic disorders of nitric oxide and arginine in metabolic syndrome and asthma and show that insulin resistance treatment can be therapeutically useful in patients with asthma in combination with obesity

Prevalence and biomarkers in metabolic syndrome

The prevalence of metabolic syndrome (MS) has a worldwide tendency to increase and depends on many components, which explains the complexity of diagnostics and approaches to the prevention and treatment of this pathology. Age, lifestyle, socioeconomic status, insulin resistance (IR), dyslipidemia, obesity and genetic predisposition are factors influencing the risk of developing and progression of MS. Features of the distribution and dysfunction of adipose tissue are important factors in the development of IR, with obesity, as well as the risk of the formation of cardiometabolic diseases and MS. ­Understanding of mechanisms is linked to advances in metabolic phenotyping. Metabolic phenotyping of obese persons is important for the development of important diseases in relation to the study of the pathophysiology of metabolic disorders, the possible concomitant disease and the search for innovative strategies for the prevention and treatment of MS. The understanding of MS mechanisms is associated with advances in metabolic phenotyping. Therefore, the relevance of further study of the pathophysiological mechanisms underlying various metabolic phenotypes of MS is one of the promising areas of modern scientific research. This review summarizes the current literature data on the prevalence of MS depending on gender, age, population, area of residence, education, level of physical activity, and many other parameters. Metabolic risks of MS development are detailed. Biological markers of MS are considered. The necessity of metabolic phenotyping of MS has been shown, which may have potential therapeutic value

Translation Lookaside Buffer on the 65-nm STG DICE Hardened Elements

This paper presents the design of hardened translation lookaside buffer based on Spaced Transistor Groups (STG) DICE cells in 65-nm bulk CMOS technology. The resistance to impacts of single nuclear particles is achieved by spacing transistors in two groups together with transistors of the output combinational logic. The elements contain two spaced identical groups of transistors. Charge collection from particle tracks by only transistors of just one of the two groups doesn’t lead to the cell upset. The proposed logical element of matching based on the STG DICE cell for a content-addressable memory was simulated using TCAD tool. The results show the resistance to impacts of single nuclear particles with linear energy transfer (LET) values up to 70 MeV×cm2/mg. Short-term noise pulses in combinational logic of the element can be observed in the range of LET values from 20 to 70 MeV×cm2/mg

OT J002656.6+284933 (CSS101212:002657+284933): An SU UMa-type dwarf nova with the longest superhump period

© The Author 2017. Published by Oxford University Press on behalf of the Astronomical Society of Japan. All rights reserved. For Permissions, please email:. We observed the 2016 outburst of OT J002656.6+284933 (CSS101212:002657+284933) and found that it has the longest recorded [0.13225(1) d on average] superhumps among SU UMa-type dwarf novae. The object is the third known SU UMa-type dwarf nova above the period gap. The outburst, however, was unlike ordinary long-period SU UMa-type dwarf novae in that it s howed two post-outburst rebrightenings. It showed superhump evolution similar to short-period SU UMa-type dwarf novae. We could constrain the mass ratio to less than 0.15 (most likely between 0.10 and 0.15) by using superhump periods in the early and post-superoutburst stages. These results suggest the possibility that OT J002656.6+284933 has an anomalously undermassive secondary and it should have followed a different evolutionary track from the standard one