Uromodulin: Relationship of protein oligomeric forms and functions

2021 ◽  
pp. 133-140
Author(s):  
Н.А. Верлов ◽  
С.Б. Ланда ◽  
В.В. Егоров ◽  
Ю.В. Эмануэль ◽  
В.Л. Эмануэль
Keyword(s):  
Surface Charge ◽  
Hydrodynamic Radius ◽  
Lower Surface ◽  
Structural Features ◽  
Major Protein ◽  
Dominant Form ◽  
Study Results ◽  
Primary Model ◽  
Urine Formation ◽  
Oligomeric Forms

Введение. Уромодулин является основным белком присутствующим в моче в норме, его физиологическая роль очень разнообразна. Оценка его вклада в стабилизацию коллоида мочи в норме и при различных патологических состояниях требует детального исследования олигомерных форм, присутствующих в моче, их структуры и функций. Цель работы - изучение структурных особенностей олигомерных форм белка уромодулина в моче здоровых добровольцев и пациентов с подтверждённым уролитиазом и выявление связи структуры белка и его роли в стабилизации коллоида мочи. Методика. Методом динамического рассеяния света, анализом треков наночастиц и измерением дзета-потенциала изучены биофизические свойства изоформ уромодулина (UM), присутствующего в нативной моче в виде олигомерных форм, из которых можно выделить 2 основные: UM(7) - глобулярная молекула массой 7MDa, характеризуется гидродинамическим радиусом Rh=90-100 нм и отрицательным поверхностным зарядом величиной 25 - 30 мВ; UM(28) - массой 28MDa обладает палочкоподобной структурой с гидродинамическим радиусом Rh=200-300 нм и существенно меньшим по величине поверхностным зарядом 0 - -7 мВ. Результаты. В норме в моче UM(7) является доминантной формой, при этом вклад UM(28) либо отсутствует, либо незначителен. При уролитиазе доля UM(7) радикально уменьшается и вклад UM(28) становится основным. В модельных экспериментах показаны различия этих переходов в моче здоровых лиц и пациентов с уролитиазом в зависимости от величины pH и концентрации одновалентных катионов: натрия, калия и аммония. Заключение. На основании полученных данных существенно расширено представление о саногенетической системе коллоидного гомеостаза мочеобразования и патогенезе кристаллогенеза. Аппроксимация выдвинутой концепции развития патологического кристаллогенеза в клиническую практику расширяют информативность превентивной диагностики уролитиаза. Introduction. Uromodulin is the major protein, which is normally present in urine and plays multiple physiological roles. Evaluation of the uromodulin contribution to stabilization of urinary colloids in normal and various pathological conditions requires a comprehensive study of uromodulin oligomeric forms occurring in urine, their structure and functions. The aim of this work was studying structural features of uromodulin oligomeric forms in the urine of healthy volunteers and patients with confirmed urolithiasis and identifying a relationship between the protein structure and role in stabilization of urinary colloids. Methods. Dynamic light scattering (DLS), nanoparticle tracking analysis (NTA), and measurement of zeta potential were used to study biophysical properties of uromodulin (UM) isoforms. UM is present in native urine as oligomeric forms, including two major ones: i) UM (7), a 7MDa globular molecule characterized by a hydrodynamic radius Rh = 90-100 nm and a negative surface charge of 25-30 mV and ii) UM (28), a rod-like 28MDa molecule with a hydrodynamic radius of Rh=200-300 nm and a significantly lower surface charge of 0 --7 mV. Results. Normally, UM (7) is a dominant form in urine whereas the UM (28) contribution is either non-existent or minor. In urolithiasis, the proportion of UM (7) decreases drastically, and the contribution of UM (28) becomes primary. Model experiments showed differences between these transitions in the urine of healthy individuals and patients with urolithiasis depending on pH values and concentrations of monovalent cations, including sodium, potassium, and ammonium. Conclusion. The study results considerably expanded the concept of the sanogenetic system of colloidal homeostasis in urine formation and the pathogenesis of crystallogenesis. Approximating the proposed concept of pathological crystallogenesis in clinical practice expands the informative value of preventive diagnosis of urolithiasis.

scholarly journals Dispersive evaluation and surface chemistry of advanced, multifunctional silica/lignin hybrid biomaterials

2013 ◽  
Vol 11 (11) ◽  
pp. 1860-1873 ◽  
Author(s):  
Magdalena Nowacka ◽  
Łukasz Klapiszewski ◽  
Małgorzata Norman ◽  
Teofil Jesionowski
Keyword(s):  
Zeta Potential ◽  
Surface Charge ◽  
Electrochemical Sensors ◽  
Relevant Information ◽  
Structural Features ◽  
Kraft Lignin ◽  
Morphological Properties ◽  
Wide Range ◽  
Hybrid Biomaterials

AbstractAdvanced silica/lignin hybrid biomaterials were obtained using hydrated or fumed silicas (Aerosil®200) and Kraft lignin as precursors, which is a cheap and biodegradable natural polymer. To extend the possible range of applications, the silicas were first modified with N-2-(aminoethyl)-3-aminopropyltrimethoxsysilane, and then with Kraft lignin, which had been oxidized with sodium periodate. The SiO2/lignin hybrids and precursors were characterised by means of determination of their physicochemical and dispersive-morphological properties. The effectiveness of silica binding to lignin was verified by FT-IR spectroscopy. The zeta potential value provides relevant information regarding interactions between colloid particles. Measurement of the zeta potential values enabled an indirect assessment of stability for the studied hybrid systems. Determination of zeta potential and density of surface charge also permitted the quantitative analysis of changes in surface charge, and indirectly confirmed the effectiveness of the proposed method for synthesis of SiO2/lignin hybrid materials. A particularly attractive feature for practical use is their stability, especially electrokinetic stability. It is expected that silica/lignin hybrids will find a wide range of applications (polymer fillers, biosorbents, electrochemical sensors), as they combine the unique properties of silica with the specific structural features of lignin. This makes these hybrids biomaterials advanced and multifunctional.

Effect of arsenate on adsorption of Zn(II) by three variable charge soils

Soil Research ◽  
2007 ◽  
Vol 45 (6) ◽  
pp. 465 ◽  
Author(s):  
Jing Liang ◽  
Ren-kou Xu ◽  
Diwakar Tiwari ◽  
An-zhen Zhao
Keyword(s):  
Zeta Potential ◽  
Surface Charge ◽  
Iron Oxides ◽  
Initial Concentration ◽  
Variable Charge ◽  
Study Results ◽  
Negative Surface ◽  
Negative Surface Charge ◽  
Enhanced Adsorption ◽  
Variable Charge Soils

The effect of arsenate on adsorption of Zn(II) in 3 variable charge soils (Hyper-Rhodic Ferralsol, Rhodic Ferralsol, and Haplic Acrisol) and the desorption of pre-adsorbed Zn(II) in the presence of arsenate were investigated in this study. Results showed that the presence of arsenate led to an increase in both the adsorption and desorption of Zn(II) in these variable charge soils. It was also suggested that the enhanced Zn(II) adsorption by arsenate was mainly due to the increase in negative surface charge of the soils induced by the specific adsorption of arsenate, and the increase in electrostatically adsorbed Zn(II) was responsible for the increase in the desorption of Zn(II). The effect of arsenate on Zn(II) adsorption primarily depends on the initial concentration of arsenate and Zn(II), the system pH, and the nature of soils. The enhanced adsorption of Zn(II) increased with the increase in the initial concentration of arsenate and the amount of arsenate adsorbed by the soils. The presence of arsenate decreased the zeta potential of soil suspensions and soil IEP and thus shifted the adsorption edge of Zn(II) to a lower pH region. The effect of arsenate on Zn(II) adsorption in these 3 soils followed the order Hyper-Rhodic Ferralsol > Rhodic Ferralsol > Haplic Acrisol, which was consistent to the contents of iron oxides in these soils and the amount of arsenate adsorbed by the soils.

Liquid Chromatographic Determination of Sphmgamne and Sphingosine: Use of the Free Sphinganine-to-Sphingosine Ratio as a Biomarker for Consumption of Fumonisins

1994 ◽  
Vol 77 (2) ◽  
pp. 533-540 ◽  
Author(s):  
Ronald T Riley ◽  
Elaine Wang ◽  
Alfred H Merrill
Keyword(s):  
De Novo ◽  
Fumonisin B1 ◽  
Chromatographic Determination ◽  
Structural Features ◽  
Serum Marker ◽  
Fungal Culture ◽  
Sphingoid Bases ◽  
Study Results ◽  
Liquid Chromatographic

Abstract Because the chemical structure of fumonisin B1 (FB1) has several structural features in common with the sphingoid bases, sphingosine and dihydro-sphingosine (sphinganine), we tested the hypothesis that the fumonisins might alter the normal cellular activity or the metabolism of endogenous free sphingoid bases. FB1 was found to be a potent inhibitor of de novo sphingolipid biosynthesis in vitro, its primary target being sphinganine N-acyl-transferase. This inhibition resulted in a decrease in the biosynthesis of sphingosine and an accumulation of free sphinganine, an intermediate in the de novo biosynthetic pathway for complex sphin-golipids. These findings led to the hypothesis that consumption of feed containing fumo|nisins should cause an increase in the ratio of free sphinganine to free sphingosine in tissues and serum. Data consistent with this hypothesis have been obtained from horses and pigs that consumed feed containing fumonisin-contaminated corn screenings and from rats fed feed supplemented with fumonisin-containing fungal culture materials or pure FBi. Thus, the ratio of free sphinganine to free sphingosine shows promise as a tissue, urine, or serum marker for animals consuming feed containing fumonisins. The present paper provides a detailed description of the extraction of free sphingoid bases and the liquid chromatographic method we used for determining the relative amounts of free sphingosine and free sphinganine in serum, urine, and various tissues of animals. Study results are summarized, and the ratio of free sphinganine to free sphingosine is discussed as a presumptive test for identifying animals consuming fumonisin-contami-nated feed.

Rationalizing the molecular origins of Ru- and Fe-based dyes for dye-sensitized solar cells

2012 ◽  
Vol 68 (2) ◽  
pp. 137-149 ◽  
Author(s):  
Kian Sing Low ◽  
Jacqueline M. Cole ◽  
Xiaolan Zhou ◽  
Nataliya Yufa
Keyword(s):  
Solar Cells ◽  
Metal Ion ◽  
Dye Sensitized Solar Cells ◽  
Protonated Form ◽  
Structural Features ◽  
Structure Property ◽  
Dye Sensitized ◽  
Study Results ◽  
Carboxylic Groups ◽  
Sensitized Solar Cells

As part of an effort to design more efficient dyes for dye-sensitized solar cells (DSCs), structure–property relationships are established in the world's best-performing chemical series of dyes: 2,2′-bipyridyl-4,4′-carboxylatoruthenium(II) complexes. Statistical analysis, based on crystallographic data from the Cambridge Structural Database, is used to determine common structural features and the effects of structural change to its salient molecular constituents. Also included is the report of two new crystal structures for tris(2,2′-bipyridyl)dichlororuthenium(II)hexahydrate and tris(2,2′-bipyridyl)iron(II)dithiocyanate; these add to this statistical enquiry. Results show that the metal (M) core exhibits a distorted octahedral environment with M—N π-backbonding effects affording the propensity of the metal ion towards oxidation. The same characteristics are observed in iron-based analogues. The role of carboxylic groups in this series of dyes is assessed by comparing complexes which contain or are devoid of COOH groups. Space-group variation and large molecular conformational differences occur when COOH groups are present, while such structural features are very similar in their absence. The nature of the anion is also shown to influence the structure of COOH-containing complexes. These structural findings are corroborated by solution-based UV–vis absorption spectroscopy and DSC device performance tests. The presence of COOH groups in this series of compounds is shown to be mandatory for dye-uptake in TiO2 in the DSC fabrication process. Throughout this study, results are compared with those of the world's most famous DSC dye, N3 (N719 in its fully protonated form): cis-bis(isothiocyanato)bis(2,2′-bipyridyl-4,4′-dicarboxylato)ruthenium(II). Overall, the molecular origins of charge-transfer in these complexes are ascertained. The findings have important implications to the materials discovery of more efficient dyes for DSC technology.

scholarly journals Rola Agencji Nieruchomości Rolnych w przemianach struktury agrarnej w Polsce

2005 ◽  
pp. 19-30
Author(s):  
Aldona Zawojska
Keyword(s):  
Agricultural Policy ◽  
Strong Correlation ◽  
The State ◽  
Family Farms ◽  
Dominant Form ◽  
State Sector ◽  
Average Area ◽  
Study Results ◽  
The Government ◽  
Ownership Transformation

The restructuring and privatisation in Poland's state sector of agriculture was (in 1991) entrusted to the Agricultural Property Agency of the State Treasury (hereafter Agricultural Property Agency). The agency was expected to play an important role in the state agricultural policy as far as structural and ownership transformation of the Polish agriculture is concerned. Almost 80% of land in the Treasury Agricultural Property Stock was taken over from former state-owned farms, asymmetrically concentrated in northern and western provinces. The purpose of liquidation of state farms was intended to strengthen the model of family farms chosen by the Government, mainly through privatisation of state land. In fact, till present the agency has sold merely one third of the land in its stock. The lease remains the dominant form applied in management of land, comprising approximately 2 million ha in permanent use among individual farmers and companies. This paper empirically explores the impacts of AP A on agrarian structure in Poland. The study results show statistically significant strong correlation between regionally distributed property in the form of land sale/land lease and the average area of individual farms.

scholarly journals Evaluation of a natural compound extracted from Dolichandrone atrovirens as a novel antioxidant agent using Caenorhabditis elegans

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0257702
Author(s):  
Manoj Limbraj Yellurkar ◽  
Vibhavana Singh ◽  
Vani Sai Prasanna ◽  
Pamelika Das ◽  
Satheeshkumar Nanjappan ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Caenorhabditis Elegans ◽  
Reactive Oxygen Species Generation ◽  
Oxidative Activity ◽  
Control Group ◽  
Absorption Study ◽  
Link Type ◽  
Study Results ◽  
Primary Model ◽  
Dolichandrone Atrovirens

The compound methyl cinnamoyl catalpol (DAM-1) was isolated from the methanol extract of Dolichandrone atrovirens. Studies have already reported the antioxidant activity of Dolichandrone atrovirens bark extract, but till date the antioxidant activity of the isolated compound DAM-1, remains unexplored. The endogenous process of reactive oxygen species generation which leads to various degenerative diseases, can be broken down using these exogenous moieties from plant origin, herein this study we sought to evaluate the antioxidant potential of the DAM-1 compound using Caenorhabditis elegans (C. elegans), which is the primary model to study the antioxidant activity of compounds. Cytotoxicity assay results showed that DAM-1 treatment in the concentration of 10, 25 and 50 μg/ml has shown 100%, 91%, and 50% survival respectively with overall p<0.0001 (treatment v/s control group). 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide–Formazan (MTT) assay results showed that treatment had better survival rates than the control group at different time intervals i.e. 48 h, and 72 h with p<0.01. Mechanosensation (behavioral study) as well as in vivo study results showed that at 0 h, 10 μg/ml of DAM-1 treatment showed a better anti-oxidative activity than the control group, 25 and 50 μg/ml of DAM-1 treated groups with p<0.001 but at 2.5 h incubation with 10, 25, 50 μg/ml of DAM-1 showed an increased anti-oxidative activity than the control group with p<0.001. Thermoresistance assay confirmed that the treatment group had more survival than control group with p<0.001. Absorption study of DAM-1 in C. elegans has shown that the absorption of the drug increases up to 180 mins with a slight decrease after 360 mins and then constant absorption up to 1440 mins. This study paves the way towards the initiative to explore the pharmacological role of DAM-1 in various oxidative stress mediated diseases at molecular levels and the absorption study points out its potential role which could be utilized in the metabolomics and proteomics analysis of this compound in other studies.

scholarly journals Structure of the Upper and Lower Surfaces of Human Corpus Callosum

2021 ◽  
Vol 12 (2) ◽  
Author(s):  
Olga Boiagina ◽  
Keyword(s):  
Corpus Callosum ◽  
Digital Camera ◽  
Lower Surface ◽  
Structural Features ◽  
Mean Value ◽  
Individual Variability ◽  
Cerebral Hemispheres ◽  
The Difference ◽  
The Individual ◽  
The Brain

The corpus callosum in the interval between the cerebral hemispheres is a plate of white matter, uneven in thickness, in which two surfaces are distinguished - the upper and lower ones, bent according to its lateral profile. The objective of the study was to study the individual variability of location of the lateral and medial longitudinal strips on the upper surface of the corpus callosum, as well as structural features of its lower surface. The material was the brain of men and women (10 specimens each) of the second period of adulthood, who died for the causes not related to the pathology of the central nervous system. After two weeks of fixation in a 10% formalin solution, the brain was prepared by separating the cerebral hemispheres and other parts of the brain from the corpus callosum, resulting in exposure of its upper and lower surface, which was photographed using a digital camera. As evidenced by the obtained data, the width of the trunk of the corpus callosum in men varies from 9 to 16 mm, whereas in women the difference between the minimum (11.0 mm) and the maximum (20.0 mm) values is greater than in men, when in fact there is only small difference of the arithmetic mean value. Thus, we offer to consider the lateral longitudinal strips to be the boundaries of the corpus callosum hemispherical part and the distance between them determines the width of this formation, which in average is 13.0 ± 2.5 mm in men and 14.4 ± 2.7 mm in women. In the meantime, the nature of the individual variability of the width of the corpus callosum trunk in women is more diverse than in men.

scholarly journals Structural and Biochemical Insights into the Reactivity of Thioredoxin h1 from Chlamydomonas reinhardtii

Antioxidants ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 10 ◽  
Author(s):  
Christophe H. Marchand ◽  
Simona Fermani ◽  
Jacopo Rossi ◽  
Libero Gurrieri ◽  
Daniele Tedesco ◽  
...  
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Active Site ◽  
3D Structure ◽  
Three Dimensional ◽  
Structural Features ◽  
Acid Dissociation ◽  
Redox Activity ◽  
Dimensional Structure ◽  
Major Protein ◽  
Acid Dissociation Constant

Thioredoxins (TRXs) are major protein disulfide reductases of the cell. Their redox activity relies on a conserved Trp-Cys-(Gly/Pro)-Pro-Cys active site bearing two cysteine (Cys) residues that can be found either as free thiols (reduced TRXs) or linked together by a disulfide bond (oxidized TRXs) during the catalytic cycle. Their reactivity is crucial for TRX activity, and depends on the active site microenvironment. Here, we solved and compared the 3D structure of reduced and oxidized TRX h1 from Chlamydomonas reinhardtii (CrTRXh1). The three-dimensional structure was also determined for mutants of each active site Cys. Structural alignments of CrTRXh1 with other structurally solved plant TRXs showed a common spatial fold, despite the low sequence identity. Structural analyses of CrTRXh1 revealed that the protein adopts an identical conformation independently from its redox state. Treatment with iodoacetamide (IAM), a Cys alkylating agent, resulted in a rapid and pH-dependent inactivation of CrTRXh1. Starting from fully reduced CrTRXh1, we determined the acid dissociation constant (pKa) of each active site Cys by Matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry analyses coupled to differential IAM-based alkylation. Based on the diversity of catalytic Cys deprotonation states, the mechanisms and structural features underlying disulfide redox activity are discussed.

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