Point mutations affecting yeast prion propagation change the structure of its amyloid fibrils

We investigated the effect of the point substitutions in the N-terminal domain of the yeast prion protein Sup35 (Sup35NMp) on the structure of its amyloid fibrils. As the objects of the study, proteins with mutations that have different influence on the [PSI+] prion propagation, but do not prevent the aggregation of Sup35NMp in vitro were chosen. The use of the wide range of physico-chemical methods allowed us to show significant differences in the structure of these aggregates, their physical size, clumping tendency. Also we demonstrated that the fluorescent probe thioflavin T (ThT) can be successfully used for investigation of subtle changes in the structural organization of fibrils formed from various Sup35NMp. The obtained results and our theoretical predictions allowed us to conclude that some of selected amino acid substitutions delimit the region of the protein that forms the core of amyloid fibrils, and change the fibrils structure. The relationship of structural features of in vitro Sup35NMp amyloid aggregates with the stability of the [PSI+] prion in vivo allowed us to suggest that oligopeptide repeats (R) of the amyloidogenic N-terminal domain of Sup35NMp from R0 to R2 play a key role in protein aggregation. Their arrangement rather than just presence is critical for propagation of the strong [PSI+] prion variants. The results confirm the suitability of the proposed combination of theoretical and empirical approaches for identifying changes in the amyloid fibrils structure, which, in turn, can significantly affect both the functional stability of amyloid fibrils and their pathogenicity.Laboratorio de Investigación y Desarrollo de Bioactivo

Isolated left ventricular apical hypoplasia with myocardial non-compaction: a case report.

Background: Isolated left ventricular apical hypoplasia (ILVAH) is a rare congenital cardiac abnormality, which might result in severe symptomatic heart failure (HF) with pulmonary hypertension, atrial fibrillation (AF), or malignant ventricular tachycardia in adults. Case summary: A 32-years-old man presented with exertional dyspnoea New York Heart Association Class II and persistent AF. Echocardiography and cardiac magnetic resonance showed the presence of (i) spherical remodelling of the left ventricle (LV) with impaired contractile function (three-dimensional ejection fraction, EF 32%); (ii) substitution of apical myocardium by fatty tissue; (iii) abnormal origin of a papillary muscle network; and (iv) an elongated right ventricle, compatible with ILVAH. In addition, non-compacted endomyocardial layer of the LV was observed. Because of a high risk of sudden cardiac death in symptomatic HF patients with reduced EF, an implantable cardioverter-defibrillator was placed which followed by pulmonary vein isolation. After the procedures and restoration of sinus rhythm, the patient demonstrated improvement in HF symptoms and exercise tolerance. This was accompanied by an enhancement of left and right ventricular systolic function by echocardiography. At 6-month, 1, and 2-year follow-up the clinical conditions of the patient and echocardiographic findings remained stable. Discussion: A rare combination of ILVAH and left ventricular myocardium non-compaction was observed in this young adult who presented with symptomatic HF and persistent AF. The use of consecutive invasive cardiac procedures leads to restoration of sinus rhythm, the improvement of myocardial contractility and clinical manifestation of HF.status: Published onlin

Study of Phosphates Sorption on the Porous Supports from Birch Bark

Изучены процессы сорбции фосфатов Na2HPO4 и KH2PO4 из водных растворов пористыми подложками из луба и коры березы. Установлено влияние концентрации солей в растворе, природы и размера частиц подложек на процесс сорбции. Показано, что по своей сорбционной активности пористая подложка из коры березы превосходит промышленные активные угли из древесины березы. Получены и обсуждены данные по кинетике сорбции фосфатов пористыми подложками из луба и коры березыProcesses of phosphates Na2HPO4 and KH2PO4 sorption from water solutions by porous supports from inner birch bark and from birch bark were studied. The influence of salts concentrations in solution, nature and size of support particles on sorption activity were established. It was shown that sorption properties of a support from birch bark is higher than that of commercial active carbon from birch wood. Kinetic features of phosphates sorption by porous supports from inner birch bark and birch bark were discusse

Influence of Conditions a Birch Outer-Bark Acetylation and Pre-Treatment on the Yield and Composition of Triterpenes Products

Изучено влияние измельчения бересты коры березы и ее кратковременной обработки перегретым водяным паром на выход и состав тритерпеновых продуктов, получаемых ацетилированием бересты уксусной кислотой. Подобраны условия активации и ацетилирования бересты, позволяющие получать преимущественно бетулин либо диацетат бетулина.Influence of a birch outer-bark grinding and short-time treatment by overheated steam on the yield and composition of triterpenes products, obtained by bark acetylation with acetic acid was studied. At selected conditions of birch outer-bark activation and acetylation the products, containing mainly betulin or betulin diacetate were produced

Influence of Conditions a Birch Outer-Bark Acetylation and Pre-Treatment on the Yield and Composition of Triterpenes Products

Изучено влияние измельчения бересты коры березы и ее кратковременной обработки перегретым водяным паром на выход и состав тритерпеновых продуктов, получаемых ацетилированием бересты уксусной кислотой. Подобраны условия активации и ацетилирования бересты, позволяющие получать преимущественно бетулин либо диацетат бетулина.Influence of a birch outer-bark grinding and short-time treatment by overheated steam on the yield and composition of triterpenes products, obtained by bark acetylation with acetic acid was studied. At selected conditions of birch outer-bark activation and acetylation the products, containing mainly betulin or betulin diacetate were produced

Synthesis and Properties of Biocomposite Fertilizers on the Basis of Urea and Birch Bark

Методами химического и рентгеноспектрального анализа, РЭМ, ЭПР, а также сорбционными изучен состав и строение биокомпозитных удобрений пролонгированного действия, полученных нанесением мочевины на пористые подложки из коры и луба березы. Установлено, что мочевина достаточно однородно распределена в изученных подложках, причем зарегистрировано наличие парамагнитных фенокси-радикалов, ионов Fe3+и Mn2+, ферромагнитных наночастиц Fe3O4. Эти парамагнитные центры могут принимать участие в адсорбции мочевины на пористых подложках. Кинетические исследования показали, что скорость сорбции мочевины пористыми подложками из водного раствора значительно превышает скорость ее десорбции из биокомпозитного удобрения в раствор. Установлено, что наиболее выраженное положительное влияние на рост кресс-салата проявляет биокомпозитное удобрение на основе коры березы. Все изученные биокомпозитные удобрения обладают пролонгированным ростостимулирующим действиемComposition and structure of biocompocite fertilizers on the basis of urea and birch bark were studied with the use of chemical and x-ray spectral analysis, SEM, EPR, and adsorption-desorption methods. It was found that urea is homogeneously distributed in studied supports. They also contain paramagnetic phenoxy-radicals, ions Fe3+ and Mn2+, ferromagnetic nanoparticles Fe3O4. This paramagnetic centers can participate in adsorption of urea on porous supports. Kinetic studies show that the rate of urea adsorption on porous supports from water solution exceeds significantly the rate of urea desorption from biocomposite fertilizer into solution. It was found that the strongly pronounced positive influence on the growth of watercres show biocomposite fertilizer on the basis of birch bark. All studied bicomposite fertilizers have a prolong action on the watercress growt

Synthesis and Characterization of Silver-Containing Nanocomposites Based on 1-Vinyl-1,2,4-triazole and Acrylonitrile Copolymer

Insoluble silver-containing nanocomposites based on 1-vinyl-1,2,4-triazole and acrylonitrile copolymer was synthesized and characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, atomic absorption, X-ray diffraction, and thermogravimetric data analysis. The silver content of the nanocomposites varied from 8.0 to 23.5% (the silver content depends on the ratio of the copolymer-silver salt). Synthesis of silver nanocomposites was carried out by thermal treatment of a polymer complex of copolymer-silver salt without the use of an additional reducing agent. X-ray diffraction was used to control the formation of silver nanoparticles at different temperatures (210°С, 220°С, and 250°С). Synthesis of nanocomposites shows a developed porous structure with a channel diameter in most cases of 1-4 microns. The EPR monitoring of the nanoparticle germination and growth reveals that the generation of the nanocomposites proceeds via a stage of complex formation between the polymeric matrix and silver ions. The synthesized nanocomposites possess paramagnetic properties and show a narrow EPR symmetric signal with the concentration of unpaired electrons of 1020 spin/g, a g-factor 2.0050, and signal width 5-6 Gs. Thermal stability of silver-containing nanocomposites is up to 270-320°C