scholarly journals Analysis of the metabolic turnover of the individual phosphate groups of phosphatidylinositol 4-phosphate and phosphatidylinositol 4,5-bisphosphate. Validation of novel analytical techniques by using 32P-labelled lipids from erythrocytes

1984 ◽  
Vol 218 (3) ◽  
pp. 785-793 ◽  
Author(s):  
P T Hawkins ◽  
R H Michell ◽  
C J Kirk
Keyword(s):  
Alkaline Phosphatase ◽  
Analytical Techniques ◽  
Erythrocyte Membranes ◽  
Intact Cells ◽  
First Order Kinetics ◽  
Phosphatase Treatment ◽  
The Many ◽  
The Individual ◽  
Phosphatidylinositol 4 ◽  
Phosphate Groups

We have developed methods that yield estimates of the 32P content of each of the individual phosphate groups of phosphatidylinositol 4-phosphate and phosphatidylinositol 4,5-bisphosphate, thus extending the information available from studies of the labelling of these lipids in intact cells or membrane preparations. The analyses are undertaken with the deacylated lipids. Assay of the 5-phosphate of phosphatidylinositol 4,5-bisphosphate is achieved by the use, under conditions of first-order kinetics, of a 5-phosphate-specific phosphomonoesterase present in isolated erythrocyte membranes [Downes, Mussat & Michell (1982) Biochem. J. 203, 169-177]. Assay of the 4-phosphate of phosphatidylinositol 4-phosphate and of the total monoester phosphate content (4-phosphate plus 5-phosphate) of phosphatidylinositol 4,5-bisphosphate employs alkaline phosphatase from bovine intestine. The radioactivity of the 1-phosphate is that remaining as organic phosphate after exhaustive alkaline phosphatase treatment. The methodology has been validated by using lipids from human erythrocytes: these contain no 32P in their 1-phosphate. These methods should be of substantial value in studies of the many cells that show rapid hormonal perturbations of phosphatidylinositol 4,5-bisphosphate metabolism.

Calcium-dependent hydrolyses of polyphosphoinositides in human erythrocyte membranes

1984 ◽  
Vol 62 (6) ◽  
pp. 363-368 ◽  
Author(s):  
R. Blaine Moore ◽  
Stanley H. Appel
Keyword(s):  
Time Course ◽  
Erythrocyte Membranes ◽  
Ionophore A23187 ◽  
Erythrocyte Ghosts ◽  
Calcium Activation ◽  
Activation Curve ◽  
Intact Cells ◽  
Calcium Dependent ◽  
Human Erythrocyte Membranes ◽  
Phosphatidylinositol 4

Incubation of erythrocytes with [32P]phosphate resulted in a linear incorporation of the label into PtdIns(4,5)P2 (phosphatidylinositol 4,5-bisphosphate), PtdIns4P (phosphatidylinositol 4-monophosphate), and PA (phosphatidic acid) over a period of 2 h at 37 °C. Exposure of 32P-labelled erythrocyte ghosts to calcium caused a loss of label from PtdIns(4,5)P2 and PtdIns4P, but not PA. The concentration of calcium required for half-maximal hydrolyses of both polyphosphoinositides was about 1 μM. Strontium, at higher concentrations, stimulated the hydrolyses of both polyphosphoinositides but barium, up to 1 mM, had little effect. Intact erythrocytes incubated in the presence of Ca–EGTA buffers and the ionophore A23187 did not show marked losses of [32P]PtdIns(4,5)P2 or [32P]PtdIns4P, but rather exhibited a dramatic increase in the level of [32P]PA. In contrast, cells which had been depleted of their ATP lost significant amounts of [32P]PtdIns(4,5)P2 and [32P]PtdIns4P and had less change in their levels of [32P]PA relative to intact cells. The calcium activation curve and the time course for [32P]PA synthesis in intact cells were similar to the calcium activation curve and the time course for the hydrolyses of [32P]PtdIns(4,5)P2 and [32P]PtdIns4P in ATP-depleted erythrocytes. These results strongly support a link between Ca2+-dependent polyphosphoinositide breakdown and PA synthesis in human erythrocytes.

Physiological and Hereditary Hyperbilirubinemia in Athletes: Role in Reducing Efficiency and Correction Methodology

2020 ◽  
Vol 5 (5) ◽  
pp. 386-393
Author(s):  
L. M. Gunina ◽  
◽  
Kazys Mylashyus ◽  
Voitenko V. L. ◽  
◽  
...  
Keyword(s):  
Physical Activity ◽  
Functional State ◽  
Oxygen Demand ◽  
Diagnostic Algorithm ◽  
Drug Prevention ◽  
The Body ◽  
Erythrocyte Membranes ◽  
Pharmacological Agents ◽  
Bilirubin Metabolism ◽  
The Individual

Under high-intensity loads, the athlete's bodies take place a number of biochemical reactions and physiological processes that can lead to hyperbilirubinemia. The factors that can initiate the onset of this phenomenon include the syndrome of micro-damage muscle, violation of the integrity of erythrocyte membranes, decreased blood pH, malnutrition and increase oxygen demand of the body. Degree of expression of manifestations of physiological bilirubinemia depends on the level of adaptation of the athlete to the physical activities offered. Hyperbilirubinemia in athletes can be one of the components of the deterioration of the functional state, forming the symptoms of endogenous intoxication. The relevance of this problem in sport lies in the relatively low detection rate of hyperbilirubinemia due to the lack of regular screening studies. However, in drawing up a plan of nutritional- metabolic support for training and competitive activity and recovery measures, must not only the individual reaction of the athlete body to physical activity, but also the severity of shifts in the indicators of bilirubin metabolism and their ratio. The article describes the reasons for the increase in bilirubin levels, which can be caused by both the effect of physical activity and by the presence of pathological processes in athletes. The factors influencing the blood serum’s bilirubin content are also highlighted, which include the state of erythrocyte cell membranes and the rate of hemoglobin destruction, the functional state of the liver, the specifics of physical loads and the use of ergogenic pharmacological agents by athletes. Particular accent has been placed on the illumination of hereditary hyperbilirubinemias, which may have been detected at the stage of selection of athletes. The most common phenomenon is Gilbert's syndrome, which occurs in 2-5% of cases in the general population, is characterized in the clinic by a benign flow and is manifested by episodes of jaundice and an increase in total bilirubin content to moderate values due to indirect. The frequency of detection of hyperbilirubinemias in the population of athletes is 4.68%, among which Gilbert's disease accounts for almost half (48.7%). Conclusion. The work highlighted the pathogenesis and diagnostic algorithm of Gilbert's disease, and also emphasized that its drug prevention and correction in athletes to maintain functional and physical fitness should be carried out taking into account anti-doping rules, which requires upon diagnosis timely receipt of a therapeutic exclusion

A Handbook to Eddic Poetry: Myths and Legends of Early Scandinavia, ed. Carolyne Larrington, Judy Quinn, and Brittany Schorn. Cambridge: Cambridge University Press, 2016, xii, 413 pp., 12 b/w ill.

Mediaevistik ◽  
2018 ◽  
Vol 31 (1) ◽  
pp. 366-366
Author(s):  
Albrecht Classen
Keyword(s):  
Old Norse ◽  
Entire Volume ◽  
Cambridge University ◽  
Critical Studies ◽  
Individual Contributions ◽  
The Many ◽  
The Individual ◽  
Made In ◽  
Scandinavian Literature

Eddic poetry constitutes one of the most important genres in Old Norse or Scandinavian literature and has been studied since the earliest time of modern-day philology. The progress we have made in that field is impressive, considering the many excellent editions and translations, not to mention the countless critical studies in monographs and articles. Nevertheless, there is always a great need to revisit, to summarize, to review, and to digest the knowledge gained so far. The present handbook intends to address all those goals and does so, to spell it out right away, exceedingly well. But in contrast to traditional concepts, the individual contributions constitute fully developed critical article, each with a specialized topic elucidating it as comprehensively as possible, and concluding with a section of notes. Those are kept very brief, but the volume rounds it all off with an inclusive, comprehensive bibliography. And there is also a very useful index at the end. At the beginning, we find, following the table of contents, a list of the contributors, unfortunately without emails, a list of translations and abbreviations of the titles of Eddic poems in the Codex Regius and then elsewhere, and a very insightful and pleasant introduction by Carolyne Larrington. She briefly introduces the genre and then summarizes the essential points made by the individual authors. The entire volume is based on the Eddic Network established by the three editors in 2012, and on two workshops held at St. John’s College, Oxford in 2013 and 2014.

Individuality and Beyond

2019 ◽  
Author(s):  
Benedetta Zavatta
Keyword(s):  
Moral Autonomy ◽  
First Line ◽  
Philosophical Interpretation ◽  
Individual Personality ◽  
The World ◽  
Regulative Ideal ◽  
Personal Library ◽  
The Many ◽  
The Individual ◽  
The Impact

Based on an analysis of the marginal markings and annotations Nietzsche made to the works of Emerson in his personal library, the book offers a philosophical interpretation of the impact on Nietzsche’s thought of his reading of these works, a reading that began when he was a schoolboy and extended to the final years of his conscious life. The many ideas and sources of inspiration that Nietzsche drew from Emerson can be organized in terms of two main lines of thought. The first line leads in the direction of the development of the individual personality, that is, the achievement of critical thinking, moral autonomy, and original self-expression. The second line of thought is the overcoming of individuality: that is to say, the need to transcend one’s own individual—and thus by definition limited—view of the world by continually confronting and engaging with visions different from one’s own and by putting into question and debating one’s own values and certainties. The image of the strong personality that Nietzsche forms thanks to his reading of Emerson ultimately takes on the appearance of a nomadic subject who is continually passing out of themselves—that is to say, abandoning their own positions and convictions—so as to undergo a constant process of evolution. In other words, the formation of the individual personality takes on the form of a regulative ideal: a goal that can never be said to have been definitively and once and for all attained.

scholarly journals Entangling Lattice-Trapped Bosons with a Free Impurity: Impact on Stationary and Dynamical Properties

Entropy ◽  
2021 ◽  
Vol 23 (3) ◽  
pp. 290
Author(s):  
Maxim Pyzh ◽  
Kevin Keiler ◽  
Simeon I. Mistakidis ◽  
Peter Schmelcher
Keyword(s):  
Structural Changes ◽  
Many Body ◽  
Wide Range ◽  
Entropy Measures ◽  
Particle Level ◽  
The Many ◽  
The One ◽  
Tunneling Dynamics ◽  
The Individual ◽  
Trapped Bosons

We address the interplay of few lattice trapped bosons interacting with an impurity atom in a box potential. For the ground state, a classification is performed based on the fidelity allowing to quantify the susceptibility of the composite system to structural changes due to the intercomponent coupling. We analyze the overall response at the many-body level and contrast it to the single-particle level. By inspecting different entropy measures we capture the degree of entanglement and intraspecies correlations for a wide range of intra- and intercomponent interactions and lattice depths. We also spatially resolve the imprint of the entanglement on the one- and two-body density distributions showcasing that it accelerates the phase separation process or acts against spatial localization for repulsive and attractive intercomponent interactions, respectively. The many-body effects on the tunneling dynamics of the individual components, resulting from their counterflow, are also discussed. The tunneling period of the impurity is very sensitive to the value of the impurity-medium coupling due to its effective dressing by the few-body medium. Our work provides implications for engineering localized structures in correlated impurity settings using species selective optical potentials.

scholarly journals Speciation of organosulfur compounds in carbonaceous chondrites

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alexander Zherebker ◽  
Yury Kostyukevich ◽  
Dmitry S. Volkov ◽  
Ratibor G. Chumakov ◽  
Lukas Friederici ◽  
...  
Keyword(s):  
Organic Matter ◽  
Analytical Techniques ◽  
Ion Cyclotron Resonance ◽  
Organosulfur Compounds ◽  
Low Oxygen ◽  
Fticr Ms ◽  
Insoluble Organic Matter ◽  
Composition And Structure ◽  
Extractable Fraction ◽  
The Individual

AbstractDespite broad application of different analytical techniques for studies on organic matter of chondrite meteorites, information about composition and structure of individual compounds is still very limited due to extreme molecular diversity of extraterrestrial organic matter. Here we present the first application of isotopic exchange assisted Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) for analysis of alkali extractable fraction of insoluble organic matter (IOM) of the Murchison and Allende meteorites. This allowed us to determine the individual S-containing ions with different types of sulfur atoms in IOM. Thiols, thiophenes, sulfoxides, sulfonyls and sulfonates were identified in both samples but with different proportions, which contribution corroborated with the hydrothermal and thermal history of the meteorites. The results were supported by XPS and thermogravimetric analysis coupled to FTICR MS. The latter was applied for the first time for analysis of chondritic IOM. To emphasize the peculiar extraterrestrial origin of IOM we have compared it with coal kerogen, which is characterized by the comparable complexity of molecular composition but its aromatic nature and low oxygen content can be ascribed almost exclusively to degradation of biomacromolecules.

scholarly journals Children’s ability to edit their memories when learning about the environment from credible and noncredible websites

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Kim P. Roberts ◽  
Katherine R. Wood ◽  
Breanne E. Wylie
Keyword(s):  
Environmental Sustainability ◽  
Choice Test ◽  
Multiple Choice Test ◽  
Sources Of Information ◽  
Older Children ◽  
Inaccurate Information ◽  
The Many ◽  
The Individual ◽  
Many Sources ◽  
Website Content

AbstractOne of the many sources of information easily available to children is the internet and the millions of websites providing accurate, and sometimes inaccurate, information. In the current investigation, we examined children’s ability to use credibility information about websites when learning about environmental sustainability. In two studies, children studied two different websites and were tested on what they had learned a week later using a multiple-choice test containing both website items and new distracters. Children were given either no information about the websites or were told that one of the websites (the noncredible website) contained errors and they should not use any information from that website to answer the test. In both studies, children aged 7- to 9-years reported information from the noncredible website even when instructed not to, whereas the 10- to 12-year-olds used the credibility warning to ‘edit out’ information that they had learned from the noncredible website. In Study 2, there was an indication that the older children spontaneously assessed the credibility of the website if credibility markers were made explicit. A plausible explanation is that, although children remembered information from the websites, they needed explicit instruction to bind the website content with the relevant source (the individual websites). The results have implications for children’s learning in an open-access, digital age where information comes from many sources, credible and noncredible. Education in credibility evaluation may enable children to be critical consumers of information thereby resisting misinformation provided through public sources.

scholarly journals Determination of the steady-state turnover rates of the metabolically active pools of phosphatidylinositol 4-phosphate and phosphatidylinositol 4,5-bisphosphate in human erythrocytes

1989 ◽  
Vol 259 (3) ◽  
pp. 893-896 ◽  
Author(s):  
C E King ◽  
P T Hawkins ◽  
L R Stephens ◽  
R H Michell
Keyword(s):  
Steady State ◽  
Rate Constants ◽  
Human Erythrocytes ◽  
Turnover Rates ◽  
Metabolic Fluxes ◽  
Metabolic Pool ◽  
Phosphatidylinositol 4 ◽  
Kinetics Of ◽  
Phosphate Groups

When intact human erythrocytes are incubated at metabolic steady state in a chloride-free medium containing [32P]Pi, there is rapid labelling of the gamma-phosphate of ATP, followed by a slower labelling of the monoester phosphate groups of phosphatidylinositol 4-phosphate (PtdIns4P) and phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] [King, Stephens, Hawkins, Guy & Michell (1987) Biochem. J. 244, 209-217]. We have analysed the early kinetics of the labelling of these phosphate groups, in order to determine: (a) the steady-state rates of the interconversions of phosphatidylinositol, PtdIns4P and PtdIns(4,5)P2; and (b) the fractions of the total cellular complement of PtdIns4P and PtdIns(4,5)P2 that participate in this steady-state turnover. The experimental data most closely fit a pattern of PtdIns4P and PtdIns(4,5)P2 turnover in which one-quarter of the total cellular complement of each lipid is in the metabolic pool that participates in rapid metabolic turnover, with rate constants of 0.028 min-1 for the interconversion of PtdIns and PtdIns4P, and of 0.010 min-1 for the PtdIns4P/PtdIns(4,5)P2 cycle. These rate constants represent metabolic fluxes of approx. 2.1 nmol of lipid/h per ml of packed erythrocytes between PtdIns and PtdIns4P and of approx. 5.7 nmol/h per ml of cells between PtdIns4P and PtdIns(4,5)P2.

scholarly journals Emergence of protocellular growth laws

2007 ◽  
Vol 362 (1486) ◽  
pp. 1841-1845 ◽  
Author(s):  
Tristan Rocheleau ◽  
Steen Rasmussen ◽  
Peter E Nielsen ◽  
Martin N Jacobi ◽  
Hans Ziock
Keyword(s):  
Kinetic Studies ◽  
Product Inhibition ◽  
Replication Process ◽  
Gene Replication ◽  
Math Biol ◽  
Curr Opin Cell Biol ◽  
Growth Laws ◽  
Internal Gene ◽  
The Many ◽  
The Individual

Template-directed replication is known to obey a parabolic growth law due to product inhibition (Sievers & Von Kiedrowski 1994 Nature 369 , 221; Lee et al . 1996 Nature 382 , 525; Varga & Szathmáry 1997 Bull. Math. Biol . 59 , 1145). We investigate a template-directed replication with a coupled template catalysed lipid aggregate production as a model of a minimal protocell and show analytically that the autocatalytic template–container feedback ensures balanced exponential replication kinetics; both the genes and the container grow exponentially with the same exponent. The parabolic gene replication does not limit the protocellular growth, and a detailed stoichiometric control of the individual protocell components is not necessary to ensure a balanced gene–container growth as conjectured by various authors (Gánti 2004 Chemoton theory ). Our analysis also suggests that the exponential growth of most modern biological systems emerges from the inherent spatial quality of the container replication process as we show analytically how the internal gene and metabolic kinetics determine the cell population's generation time and not the growth law (Burdett & Kirkwood 1983 J. Theor. Biol . 103 , 11–20; Novak et al . 1998 Biophys. Chem . 72 , 185–200; Tyson et al . 2003 Curr. Opin. Cell Biol . 15 , 221–231). Previous extensive replication reaction kinetic studies have mainly focused on template replication and have not included a coupling to metabolic container dynamics (Stadler et al . 2000 Bull. Math. Biol . 62 , 1061–1086; Stadler & Stadler 2003 Adv. Comp. Syst . 6 , 47). The reported results extend these investigations. Finally, the coordinated exponential gene–container growth law stemming from catalysis is an encouraging circumstance for the many experimental groups currently engaged in assembling self-replicating minimal artificial cells (Szostak 2001 et al . Nature 409 , 387–390; Pohorille & Deamer 2002 Trends Biotech . 20 123–128; Rasmussen et al . 2004 Science 303 , 963–965; Szathmáry 2005 Nature 433 , 469–470; Luisi et al . 2006 Naturwissenschaften 93 , 1–13). 1

scholarly journals Property and Organization Studies

2017 ◽  
Vol 40 (4) ◽  
pp. 497-513 ◽  
Author(s):  
Nicolas Bencherki ◽  
Alaric Bourgoin
Keyword(s):  
Speech Acts ◽  
Black Box ◽  
Organization Studies ◽  
Crack Open ◽  
Legal Definition ◽  
The Many ◽  
Property Changes ◽  
The Individual

Property is pervasive, and yet we organization scholars rarely discuss it. When we do, we think of it as a black-boxed concept to explain other phenomena, rather than studying it in its own right. This may be because organization scholars tend to limit their understanding of property to its legal definition, and emphasize control and exclusion as its defining criteria. This essay wishes to crack open the black box of property and explore the many ways in which possessive relations are established. They are achieved through work, take place as we make sense of signs, are invoked into existence in our speech acts, and travel along sociomaterial networks. Through a fictionalized account of a photographic exhibition, we show that property overflows its usual legal-economic definition. Building on the case of the photographic exhibit, we show that recognizing the diversity of property changes our rapport with organization studies as a field, by unifying its approaches to the individual-vs.-collective dilemma. We conclude by noting that if theories can make a difference, then whoever controls the assignment of property – including academics who ascribe properties to their objects of study – decides not only who has or who owns what, but also who or what that person or thing can be.

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