scholarly journals Routes for Potassium Ions across Mitochondrial Membranes: A Biophysical Point of View with Special Focus on the ATP-Sensitive K+ Channel

Biomolecules ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1172
Author(s):  
Yevheniia Kravenska ◽  
Vanessa Checchetto ◽  
Ildiko Szabo
Keyword(s):  
Point Of View ◽  
K Channel ◽  
Special Focus ◽  
Potassium Ions ◽  
Mitochondrial Membranes ◽  
Inner Mitochondrial Membrane ◽  
K Uptake ◽  
Molecular Identity ◽  
The Matrix ◽  
Multiple Routes

Potassium ions can cross both the outer and inner mitochondrial membranes by means of multiple routes. A few potassium-permeable ion channels exist in the outer membrane, while in the inner membrane, a multitude of different potassium-selective and potassium-permeable channels mediate K+ uptake into energized mitochondria. In contrast, potassium is exported from the matrix thanks to an H+/K+ exchanger whose molecular identity is still debated. Among the K+ channels of the inner mitochondrial membrane, the most widely studied is the ATP-dependent potassium channel, whose pharmacological activation protects cells against ischemic damage and neuronal injury. In this review, we briefly summarize and compare the different hypotheses regarding the molecular identity of this patho-physiologically relevant channel, taking into account the electrophysiological characteristics of the proposed components. In addition, we discuss the characteristics of the other channels sharing localization to both the plasma membrane and mitochondria.

scholarly journals Protein sorting between mitochondrial membranes specified by position of the stop-transfer domain.

1988 ◽  
Vol 106 (5) ◽  
pp. 1499-1505 ◽  
Author(s):  
M Nguyen ◽  
A W Bell ◽  
G C Shore
Keyword(s):  
G Protein ◽  
Simple Extension ◽  
Intermembrane Space ◽  
Mitochondrial Membranes ◽  
Inner Mitochondrial Membrane ◽  
The Matrix ◽  
Targeting Signal ◽  
Vesicular Stomatitis ◽  
Matrix Precursor ◽  
Identical Fashion

Recently, we fused a matrix-targeting signal to a large fragment of vesicular stomatitis virus G protein, which contains near its COOH-terminus a well-characterized endoplasmic reticulum (ER) stop-transfer sequence; the hybrid G protein was sorted to the inner mitochondrial membrane (Nguyen, M., and G. C. Shore. 1987. J. Biol. Chem. 262:3929-3931). Here, we show that the 19 amino acid G stop-transfer domain functions in an identical fashion when inserted toward the COOH-terminus of an otherwise normal matrix precursor protein, pre-ornithine carbamyl transferase; after import, the mutant protein was found anchored in the inner membrane via the stop-transfer sequence, with its NH2 terminus facing the matrix and its short COOH-terminal tail located in the intermembrane space. However, when the G stop-transfer sequence was placed near the NH2 terminus, the protein was inserted into the outer membrane, in the reverse orientation (NH2 terminus facing out, with a large COOH-terminal fragment located in the intermembrane space). These observations for mitochondrial topogenesis can be explained by a simple extension of existing models for ER sorting.

scholarly journals Matrix integrals & finite holography

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Dionysios Anninos ◽  
Beatrix Mühlmann
Keyword(s):  
Critical Exponents ◽  
Continuum Theory ◽  
Point Of View ◽  
Leading Order ◽  
Minimal Models ◽  
Point Evaluation ◽  
Brst Cohomology ◽  
Matrix Integrals ◽  
The Matrix ◽  
The Continuum

Abstract We explore the conjectured duality between a class of large N matrix integrals, known as multicritical matrix integrals (MMI), and the series (2m − 1, 2) of non-unitary minimal models on a fluctuating background. We match the critical exponents of the leading order planar expansion of MMI, to those of the continuum theory on an S2 topology. From the MMI perspective this is done both through a multi-vertex diagrammatic expansion, thereby revealing novel combinatorial expressions, as well as through a systematic saddle point evaluation of the matrix integral as a function of its parameters. From the continuum point of view the corresponding critical exponents are obtained upon computing the partition function in the presence of a given conformal primary. Further to this, we elaborate on a Hilbert space of the continuum theory, and the putative finiteness thereof, on both an S2 and a T2 topology using BRST cohomology considerations. Matrix integrals support this finiteness.

Fibre-Matrix Interface Development during High Temperature Exposition of Long Fibre Reinforced SiOC Matrix

2013 ◽  
Vol 592-593 ◽  
pp. 401-404
Author(s):  
Zdeněk Chlup ◽  
Martin Černý ◽  
Adam Strachota ◽  
Martina Halasova ◽  
Ivo Dlouhý
Keyword(s):  
High Temperature ◽  
Crack Formation ◽  
Fracture Behaviour ◽  
Point Of View ◽  
Reinforced Composites ◽  
Matrix Interface ◽  
Significant Damage ◽  
The Matrix ◽  
Fibre Matrix ◽  
Fibre Reinforced Composites

The fracture behaviour of long fibre reinforced composites is predetermined mainly by properties of fibre-matrix interface. The matrix prepared by pyrolysis of polysiloxane resin possesses ability to resist high temperatures without significant damage under oxidising atmosphere. The application is therefore limited by fibres and possible changes in the fibre matrix interface. The study of development of interface during high temperature exposition is the main aim of this contribution. Application of various techniques as FIB, GIS, TEM, XRD allowed to monitor microstructural changes in the interface of selected places without additional damage caused by preparation. Additionally, it was possible to obtain information about damage, the crack formation, caused by the heat treatment from the fracture mechanics point of view.

scholarly journals Reciprocity in the Civil Economy: a Critical Assessment

2018 ◽  
Vol 6 (1) ◽  
pp. 63-74
Author(s):  
María Guadalupe Martino ◽  
Christian Müller
Keyword(s):  
Point Of View ◽  
Social Market Economy ◽  
Special Focus ◽  
Economic Market ◽  
Homo Oeconomicus ◽  
Market Interactions ◽  
Incentive Compatible ◽  
The Social ◽  
Civil Economy ◽  
Social Market

Abstract The civil economy approach is an attempt to reconcile economic market interactions with the normative standards of traditional virtue ethics. We analyze critically some of its main elements with a special focus on the concept of reciprocity, which plays a central role in the whole approach. Its strengths include, among others, virtue orientation, emphasis on happiness rather than utility, and in particular the notion of reciprocity. However, we argue that this concept of reciprocity would on average not be incentive compatible, and from a methodological point of view, the implied hypothesis of a homo reciprocans is not a viable alternative to the standard model of homo oeconomicus. We also consider that the approach is not entirely new, as it shares many characteristics with the social market economy conception.

scholarly journals MYSTERY AS A META-GENRE IN THE DRAMA OF THE TWENTIETH CENTURY

2021 ◽  
pp. 18-26
Author(s):  
K. Oliinyk
Keyword(s):  
Twentieth Century ◽  
World Order ◽  
Semantic Content ◽  
Point Of View ◽  
Dramatic Works ◽  
Life And Death ◽  
The Matrix ◽  
General Feeling ◽  
The Aesthetic ◽  
Definition Of

The article examines the specificity of existence of the renewed mystery genre as a meta genre in the twentieth century. The main literary study views on the definition of ancient and medieval / Christian ritual mystery are analyzed. The beginning of the twentieth century was full of a general feeling of catastrophe and tragic hopelessness. In artistic terms, the consequence of this was the activation of Christian issues, motives, plots, religious genres (miracles, morality and mystery). The most universal from the point of view of the ideological message and content for the writers of the twentieth century. was the matrix of the medieval mystery, which retained the ritual basis in its primary structure. This made it possible for the multilevel organization of the action and the space for it. The genre of medieval mystery is being modified, it ceases to be a purely form of religious action and acquires the quality of a meta genre. There is a transition from the religious sphere to the secular one, and the aesthetic one is replacing the didactic load. Mystery begins to exist on the edge of genres as a synthetic formation, showing intentions to “help” other genres. A large number of dramatic works of the twentieth century. ("Forest Song" by Lesia Ukrainka, "Iconostasis of Ukraine" by Vіra Vovk) comes close to the mystery, using its archetypal components: the ideas of faith in the absolute beginning, governing the eternal rotation of life and death, world order and harmony, death and rebirth, transformations of the human soul, chosenness and initiation associated with trials, sacrifice, deepening into mysticism. Such works are a certain imitation with elements of mythological or religious subjects. So, the twentieth century, actualizes a certain involvement of the semantic content of dramas to the mysteries, bringing the mystery to the level of the meta genre.

The pH sensor of the plant K+-uptake channel KAT1 is built from a sensory cloud rather than from single key amino acids

2012 ◽  
Vol 442 (1) ◽  
pp. 57-63 ◽  
Author(s):  
Wendy González ◽  
Janin Riedelsberger ◽  
Samuel E. Morales-Navarro ◽  
Julio Caballero ◽  
Jans H. Alzate-Morales ◽  
...  
Keyword(s):  
Ph Sensor ◽  
Structural Models ◽  
Voltage Sensor ◽  
Activation Mechanism ◽  
Potassium Ions ◽  
Acid Activation ◽  
Extracellular Loop ◽  
K Uptake ◽  
Transmembrane Segments ◽  
Ph Dependency

The uptake of potassium ions (K+) accompanied by an acidification of the apoplasm is a prerequisite for stomatal opening. The acidification (approximately 2–2.5 pH units) is perceived by voltage-gated inward potassium channels (Kin) that then can open their pores with lower energy cost. The sensory units for extracellular pH in stomatal Kin channels are proposed to be histidines exposed to the apoplasm. However, in the Arabidopsis thaliana stomatal Kin channel KAT1, mutations in the unique histidine exposed to the solvent (His267) do not affect the pH dependency. We demonstrate in the present study that His267 of the KAT1 channel cannot sense pH changes since the neighbouring residue Phe266 shifts its pKa to undetectable values through a cation–π interaction. Instead, we show that Glu240 placed in the extracellular loop between transmembrane segments S5 and S6 is involved in the extracellular acid activation mechanism. Based on structural models we propose that this region may serve as a molecular link between the pH- and the voltage-sensor. Like Glu240, several other titratable residues could contribute to the pH-sensor of KAT1, interact with each other and even connect such residues far away from the voltage-sensor with the gating machinery of the channel.

Infinitival complementation from Caucasian Albanian to Modern Udi

2015 ◽  
Vol 5 (1) ◽  
pp. 110-138
Author(s):  
Dmitry Ganenkov
Keyword(s):  
19Th Century ◽  
Syntactic Structure ◽  
Point Of View ◽  
Historical Changes ◽  
Case Marking ◽  
The Matrix ◽  
Infinitival Complements ◽  
Diachronic Changes

The article investigates diachronic changes in infinitival complementation from Caucasian Albanian to modern Udi dialects. It describes the syntactic structure of infinitival complements in Caucasian Albanian, 19th century Vartashen Udi and two modern dialects, and concentrates on case marking of overt subjects in constructions with the matrix verbs ‘can, be able’, ‘begin’ and ‘want’. From a diachronic point of view, the data presented in the article allow us to conclude that historical changes in both the lexical form of complement-taking predicates and the morphology of their complements obey Cristofaro’s (2003) Complement Deranking Hierarchy.

New insights on the taxonomy and phylogenetic relationships of the Neotropical genus Phoebis (Pieridae: Coliadinae) revealed by molecular and morphological data

Zootaxa ◽  
2018 ◽  
Vol 4457 (1) ◽  
pp. 179 ◽  
Author(s):  
LEIDYS MURILLO-RAMOS ◽  
RENZO HERNÁNDEZ TORRES ◽  
RAYNER NÚÑEZ ÁGUILA ◽  
ROGER AYAZO
Keyword(s):  
Morphological Characters ◽  
Point Of View ◽  
Morphological Data ◽  
Caribbean Region ◽  
Greater Antilles ◽  
Data Set ◽  
Mitochondrial Coi ◽  
The Matrix ◽  
Taxonomic Point

Phoebis Hübner (1819) is a genus of the Neotropical subfamily Coliadinae (Lepidoptera: Pieridae). The highest diversity is found in the Greater Antilles islands in the Caribbean region. Although from the taxonomic point of view, Phoebis seems to be a stable genus, there is no phylogenetic hypothesis corroborating the monophyly of the genus. In this study, we used both morphological characters and a genetic dataset consisting of one mitochondrial (COI) and three nuclear markers (RpS5, MDH, Wingless). The matrix was concatenated and analysed with parsimony under implied weights (IW). Also, the concatenated data set was analysed using maximum likelihood and Bayesian inference evolutionary methods, and ancestral states reconstruction with characters traditionally used for classification of Phoebis was carried out. The same topology was recovered by Parsimony, ML and BI analysis, and suggest that Phoebis is not a monophyletic genus, with Aphrissa and Rhabdodryas nested within it. Our findings allow us to consider the genera Rhabdodryas syn.rev. and Aphrissa syn.rev. to be synonyms of Phoebis. These results have implications for the systematics of Phoebis and the genera that should be accepted in Coliadinae.

scholarly journals Molecular mechanism of mitochondrial phosphatidate transfer by Ups1

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Jiuwei Lu ◽  
Chun Chan ◽  
Leiye Yu ◽  
Jun Fan ◽  
Fei Sun ◽  
...  
Keyword(s):  
Conformational Changes ◽  
Mitochondrial Membrane ◽  
Outer Mitochondrial Membrane ◽  
Mitochondrial Membranes ◽  
Inner Mitochondrial Membrane ◽  
Membrane Interaction ◽  
Detailed Mechanism ◽  
Physiological Regulator ◽  
Membrane Bound ◽  
Dynamics Simulations

AbstractCardiolipin, an essential mitochondrial physiological regulator, is synthesized from phosphatidic acid (PA) in the inner mitochondrial membrane (IMM). PA is synthesized in the endoplasmic reticulum and transferred to the IMM via the outer mitochondrial membrane (OMM) under mediation by the Ups1/Mdm35 protein family. Despite the availability of numerous crystal structures, the detailed mechanism underlying PA transfer between mitochondrial membranes remains unclear. Here, a model of Ups1/Mdm35-membrane interaction is established using combined crystallographic data, all-atom molecular dynamics simulations, extensive structural comparisons, and biophysical assays. The α2-loop, L2-loop, and α3 helix of Ups1 mediate membrane interactions. Moreover, non-complexed Ups1 on membranes is found to be a key transition state for PA transfer. The membrane-bound non-complexed Ups1/ membrane-bound Ups1 ratio, which can be regulated by environmental pH, is inversely correlated with the PA transfer activity of Ups1/Mdm35. These results demonstrate a new model of the fine conformational changes of Ups1/Mdm35 during PA transfer.

Role of Information Technology on Supply Chain Management of Pharmaceutical Industry

2018 ◽  
Vol 8 (2) ◽  
pp. 39-68
Author(s):  
Saibal Kumar Saha ◽  
Ajeya Jha
Keyword(s):  
Information Technology ◽  
Supply Chain ◽  
Supply Chain Management ◽  
Pharmaceutical Industry ◽  
Point Of View ◽  
Special Focus ◽  
Successful Implementation ◽  
Chain Management ◽  
Role Of It

Supply Chain Management SCM is a very critical part of any business. A well-coordinated SCM can improve the efficiency of the business and help in cost reduction. As information technology (IT) is being used widely across all businesses, SCM can benefit to a large extent by the use of IT. This article reviews a number of papers in this field and suggests research gaps for further exploration. The aim of this article is to review the literature on the role of IT on supply chain management (SCM) with special focus on the pharmaceutical industry and suggest possible gaps from the point of view of researchers and practitioners. The article finds that IT has made a significant impact in improving the efficiency of SCM. But its successful implementation and collaboration with other firms is the key to success for an efficient SCM. Within each category, gaps have been identified.

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