scholarly journals Different structural states of a microtubule cross-linking molecule, captured by quick-freezing motile axostyles in protozoa.

1986 ◽  
Vol 103 (6) ◽  
pp. 2209-2227 ◽  
Author(s):  
J E Heuser
Keyword(s):  
Active Role ◽  
Longitudinal Shear ◽  
The Other ◽  
Cross Bridge ◽  
Other Hand ◽  
Quick Freezing ◽  
Cross Links ◽  
Dynein Arms ◽  
The Cross ◽  
Cross Bridges

Freeze-etch preparation of the laminated bundles of microtubules in motile axostyles demonstrates that the cross-bridges populating individual layers or laminae are structurally similar to the dynein arms of cilia and flagellae. Also, like dynein, they are extracted by high salt and undergo a change in tilt upon removal of endogenous ATP (while the axostyle as a whole straightens and becomes stiff). On the other hand, the bridges running between adjacent microtubule laminae in the axostyle turn out to be much more delicate and wispy in appearance, and display no similarity to dynein arms. Thus we propose that the internal or "intra-laminar" cross-bridges are the active force-generating ATPases in this system, and that they generate overall bends or changes in the helical pitch of the axostyle by altering the longitudinal and lateral register of microtubules in each lamina individually; e.g., by "warping" each lamina and creating longitudinal shear forces within it. The cross-links between adjacent laminae, on the other hand, would then simply be force-transmitting elements that serve to translate the shearing forces generated within individual laminae into overall helical shape changes. (This hypothesis differs from the views of earlier workers who considered a more active role for the later cross-links, postulating that they cause an active sliding between adjacent layers that somehow leads to axostyle movement.) Also described here are physical connections between adjacent intra-laminar cross-bridges, structurally analogous to the overlapping components of the outer dynein arms of cilia and flagella. As with dynein, these may represent a mechanism for propagating local changes from cross-bridge to cross-bridge down the axostyle, as occurs during the passage of bends down the length of the organelle.

Plaidoyer pour une autre constitution

Res Publica ◽  
1970 ◽  
Vol 16 (1) ◽  
pp. 117-132
Author(s):  
Bernard Remiche ◽  
Charles-Etienne Lagasse
Keyword(s):  
The Other ◽  
Federal State ◽  
Critical Examination ◽  
National Party ◽  
Traditional Values ◽  
Unitary State ◽  
Other Hand ◽  
Federal Constitution ◽  
The Cross

The 1970 amended Belgian Constitution is at the cross-roads of two currents of history, on one hand, once more the traditional values of the Occidental society ; on the other hand a double communal pressure contests an unitary state : from underneath affirmation of three Belgiannational communities, from above, apparition of a «supra-national party».The authors make a critical examination of the cropping up of bonding institutions in a «pré-fédéral» state, then they clearly state the principles of a really federal Constitution based upon the acknowledgement of the 2 large communities and the 3 regions and the principles of a democratic organization of an economic politic.

scholarly journals Wieloaspektowość międzyjęzykowej ekwiwalencji stałych połączeń wyrazowych a ujęcie onomazjologiczne na przykładzie frazeologizmów typu tęga głowa

2020 ◽  
pp. 333-355
Author(s):  
Joanna Szerszunowicz ◽  
Keyword(s):  
Linguistic Analysis ◽  
Lexical Item ◽  
The Other ◽  
Target Language ◽  
Source Language ◽  
Multiword Expressions ◽  
Other Hand ◽  
Minor Significance ◽  
The Cross

The aim of this paper is to discuss the usefulness and reliability of the onomasiological approach in the cross-linguistic analysis of fixed multiword expressions based on the example of Polish phrases coined according to the model: ADJECTIVENOM FEM SING + GŁOWA ‘HEAD’ and their English and Italian counterparts. The three corpora are constituted by expressions registered in general and phraseological dictionaries of the respective languages to ensure that the units belong to the canon of Polish, English and Italian phraseological stock. The analysis of units collected for the purpose of the study clearly shows that in order to determine the true picture of cross-linguistic equivalence, the study should be focused on semantics of analysed phrases. Furthermore, the formal aspectmay be of minor significance in some cases due to the similarity of imagery of a source language idiom and the target language lexical item. On the other hand, stylistic value may have a great impact on the relation of cross-linguistic correspondence of the analysed units.

scholarly journals Cross-linker system between neurofilaments, microtubules and membranous organelles in frog axons revealed by the quick-freeze, deep-etching method

1982 ◽  
Vol 94 (1) ◽  
pp. 129-142 ◽  
Author(s):  
N Hirokawa
Keyword(s):  
Chemical Extraction ◽  
Distilled Water ◽  
Deep Etching ◽  
Cross Links ◽  
Cross Linker ◽  
The Cross ◽  
Cross Bridges ◽  
20 Nm ◽  
Soluble Material ◽  
Soluble Components

The elaborate cross-connections among membranous organelles (MO), microtubules (MT), and neurofilaments (NF) were demonstrated in unifixed axons by the quick-freeze, deep-etch, and rotary-shadowing method. They were categorized into three groups: NF-associated cross-linker, MT-associated cross-bridges, and long cross-links in the subaxolemmal space. Other methods were also employed to make sure that the observed cross-connections in the unfixed axons were not a result of artifactual condensation or precipitation of soluble components or salt during deep-etching. Axolemma were permeablized either chemically (0.1% saponin) or physically (gentle homogenization), to allow egress of their soluble components from the axon; or else the axons were washed with distilled water after fixation. After physical rupture of the axolemma or saponin treatment, most of the MO remained intact. MT were stabilized by adding taxol in the incubation medium. Axons prepared by these methods contained many longitudinally oriented NF connected to each other by numerous fine cross-linkers (4-6 nm in diameter, 20-50 nm in length). Two specialized regions were apparent within the axons: one composed of fascicles of MT linked with each other by fine cross-bridges; the other was in the subaxolemmal space and consisted of actinlike filaments and a network of long cross-links (50-150 nm) which connected axolemma and actinlike filaments with NF and MT. F-actin was localized to the subaxolemmal space by the nitrobenzooxadiazol phallacidin method. MO were located mainly in these two specialized regions and were intimately associated with MT via fine short (10-20 nm in length) cross-bridges. Cross-links from NF to MO and MT were also common. All these cross-connections were observed after chemical extraction or physical rupture of the axon; however, these procedures removed granular materials which were attached to the filaments in the fresh unextracted axons. The cross-connections were also found in the axons washed with distilled water after fixation. I conclude that the cross- connections are real structures while the granular material is composed of soluble material, probably protein in nature.

The Aesthetic Mediation

2018 ◽  
pp. 143-200
Author(s):  
Richard Viladesau
Keyword(s):  
Nineteenth Century ◽  
Visual Arts ◽  
The Other ◽  
Romantic Period ◽  
Popular Piety ◽  
Biblical Scholarship ◽  
Other Hand ◽  
The Cross ◽  
The Aesthetic ◽  
Naturalistic Realism

In the visual arts of the Romantic period the crucifixion of Christ often became a representation of the sufferings of humanity. Caspar David Friedrich’s paintings placed the cross in the context of the immensity of nature. Toward the end of the nineteenth century there was an increasing tendency to portray Jesus’ suffering in the genre of naturalistic realism. Some painters consciously attempted to incorporate the findings of modern biblical scholarship, rather than follow traditional models. Early film representations, on the other hand, tended to rely on classical types and popular piety.

scholarly journals FmhA and FmhC of Staphylococcus aureus incorporate serine residues into peptidoglycan cross-bridges

2020 ◽  
Vol 295 (39) ◽  
pp. 13664-13676 ◽  
Author(s):  
Stephanie Willing ◽  
Emma Dyer ◽  
Olaf Schneewind ◽  
Dominique Missiakas
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Binding Proteins ◽  
Penicillin Binding Proteins ◽  
Daughter Cells ◽  
Cross Bridge ◽  
Resistant Strains ◽  
The Cross ◽  
Cross Bridges ◽  
Adjacent Wall

Staphylococcal peptidoglycan is characterized by pentaglycine cross-bridges that are cross-linked between adjacent wall peptides by penicillin-binding proteins to confer robustness and flexibility. In Staphylococcus aureus, pentaglycine cross-bridges are synthesized by three proteins: FemX adds the first glycine, and the homodimers FemA and FemB sequentially add two Gly-Gly dipeptides. Occasionally, serine residues are also incorporated into the cross-bridges by enzymes that have heretofore not been identified. Here, we show that the FemA/FemB homologues FmhA and FmhC pair with FemA and FemB to incorporate Gly-Ser dipeptides into cross-bridges and to confer resistance to lysostaphin, a secreted bacteriocin that cleaves the pentaglycine cross-bridge. FmhA incorporates serine residues at positions 3 and 5 of the cross-bridge. In contrast, FmhC incorporates a single serine at position 5. Serine incorporation also lowers resistance toward oxacillin, an antibiotic that targets penicillin-binding proteins, in both methicillin-sensitive and methicillin-resistant strains of S. aureus. FmhC is encoded by a gene immediately adjacent to lytN, which specifies a hydrolase that cleaves the bond between the fifth glycine of cross-bridges and the alanine of the adjacent stem peptide. In this manner, LytN facilitates the separation of daughter cells. Cell wall damage induced upon lytN overexpression can be alleviated by overexpression of fmhC. Together, these observations suggest that FmhA and FmhC generate peptidoglycan cross-bridges with unique serine patterns that provide protection from endogenous murein hydrolases governing cell division and from bacteriocins produced by microbial competitors.

Guarding the Great Wall?—jurisprudential review of treaty interpretative tools in Chinese BIT-based arbitration cases

2020 ◽  
Author(s):  
Shen Wei
Keyword(s):  
Dispute Settlement ◽  
Active Role ◽  
The Other ◽  
Policy Response ◽  
Appellate Body ◽  
Other Hand ◽  
The Us ◽  
Great Wall ◽  
The Eu

Abstract Inconsistency has been said to be one of the most severe shortcomings the existing investor–State dispute settlement (the ISDS) system possesses. Inconsistency, if not cured, is likely to affect the legitimacy of the ISDS. Partly in response to the claims of inconsistency and illegitimacy of the ISDS, the EU has proposed to have a permanent investment court to replace the ISDS while the US proposed to have an appellate body for the current ISDS along with a large camp of undecided states having no firm position on the ISDS reform. China, on the other hand, has not issued an official response to the concept of a permanent investment court, partially because of its less active role in the use of the existing ISDS. More recent years have witnessed China’s increasing involvement in ISDS cases. The purpose of this article is to review these China BIT-related ISDS cases, in particular, the awards on jurisdiction, and the tribunals’ varying techniques in interpreting the ISDS clauses in China’s BITs with a focus on the jurisprudential analyses of these cases and the tribunals’ treaty interpretive techniques. Not surprisingly, the interpretative tendency has been quite uniform. In brief, the tribunals have tended to be more expansive when they were called upon to determine the jurisdictional issues. Although this article is largely jurisprudential, a sense of the tribunals’ arbitral techniques may help shape some foundational underpinnings for China’s policy response to the proposals to reform the ISDS system made by the EU, the US, and others.

The Attitudes of the Secular Historians of the Age of Justinian Towards the Classical Past

Traditio ◽  
1976 ◽  
Vol 32 (1) ◽  
pp. 353-358 ◽  
Author(s):  
J. A. S. Evans
Keyword(s):  
Subject Matter ◽  
The Other ◽  
Literary Style ◽  
Ecclesiastical History ◽  
Other Hand ◽  
The Cross ◽  
Classical Traditions ◽  
Historical Causation ◽  
Eusebius Of Caesarea ◽  
The Church

I shall begin with a definition. I am dealing with ‘secular historians,’ and thus I am excluding ecclesiastical history, and chronography. The second of these two genres, chronography, continued a tradition which goes back as far as Thucydides' contemporary, Hellanicus, but under a Christian empire it acquired a Christian bias and dropped any pretence of literary style. ‘Ecclesiastical history,’ which, as far as we know, was invented by Eusebius of Caesarea, and displays a somewhat unclassical passion for documentation, dealt with the church and history as it affected the church. Its presuppositions about historical causation were Christian. The secular historians, on the other hand, continued the classical traditions of historiography begun by Herodotus and Thucydides, and their subject matter was war and politics, and the cross between the two, which was diplomacy.

How our word choices can empower our students

2018 ◽  
Vol 100 (3) ◽  
pp. 51-54
Author(s):  
Lauren Porosoff
Keyword(s):  
Active Role ◽  
The Other ◽  
Clear Picture ◽  
Other Hand ◽  
Student Identities

What teachers write about students has enormous potential to affect their lives. Lauren Porosoff encourages teachers to use their words to empower students to take an active role in their own learning. When teachers use adjectives to describe students, they may be attaching certain fixed characteristics to those students. Verbs, on the other hand, put the focus on behavior, and adverbs bring attention to how students execute certain behaviors. Nouns can give a clear picture of what students are doing, and deliberate use of conjunctions can put the emphasis on the correct pieces of information. And avoiding overuse of the pronoun I can help teachers keep the focus off themselves, while using students’ preferred pronouns conveys respect for student identities.

scholarly journals THE DOUBLE ARRAY OF FILAMENTS IN CROSS-STRIATED MUSCLE

1957 ◽  
Vol 3 (5) ◽  
pp. 631-648 ◽  
Author(s):  
H. E. Huxley
Keyword(s):  
Striated Muscle ◽  
The Other ◽  
Thin Sections ◽  
Alternative Models ◽  
Double Array ◽  
The Cross ◽  
Cross Bridges

The conditions under which one might expect to see the secondary filaments (if they exist) in longitudinal sections of striated muscle, are discussed. It is shown that these conditions were not satisfied in previously published works for the sections were too thick. When suitably thin sections are examined, the secondary filaments can be seen perfectly easily. It is also possible to see clearly other details of the structure, notably the cross-bridges between primary and secondary filaments, and the tapering of the primary filaments at their ends. The arrangement of the filaments and the changes associated with contraction and with stretch are identical to those already deduced from previous observations and described in terms of the interdigitating filament model in previous papers. There are therefore excellent grounds for believing that this model is correct. The alternative models which have been proposed appear to be incompatible both with the present observations and with much of the other available evidence.

scholarly journals Mechanical transients initiated by photolysis of caged ATP within fibers of insect fibrillar flight muscle.

1991 ◽  
Vol 98 (4) ◽  
pp. 657-679 ◽  
Author(s):  
M Yamakawa ◽  
Y E Goldman
Keyword(s):  
Rate Constant ◽  
Time Course ◽  
Flight Muscle ◽  
Order Rate Constant ◽  
Stretch Activation ◽  
Pulse Photolysis ◽  
Caged Atp ◽  
Cross Bridge ◽  
The Cross ◽  
Cross Bridges

Kinetics of the cross-bridge cycle in insect fibrillar flight muscle have been measured using laser pulse photolysis of caged ATP and caged inorganic phosphate (Pi) to produce rapid step increases in the concentration of ATP and Pi within single glycerol-extracted fibers. Rapid photochemical liberation of 100 microM-1 mM ATP from caged ATP within a fiber caused relaxation in the absence of Ca2+ and initiated an active contraction in the presence of approximately 30 microM Ca2+. The apparent second order rate constant for detachment of rigor cross-bridges by ATP was between 5 x 10(4) and 2 x 10(5) M-1s-1. This rate is not appreciably sensitive to the Ca2+ or Pi concentrations or to rigor tension level. The value is within an order of magnitude of the analogous reaction rate constant measured with isolated actin and insect myosin subfragment-1 (1986. J. Muscle Res. Cell Motil. 7:179-192). In both the absence and presence of Ca2+ insect fibers showed evidence of transient cross-bridge reattachment after ATP-induced detachment from rigor, as found in corresponding experiments on rabbit psoas fibers. However, in contrast to results with rabbit fibers, tension traces of insect fibers starting at different rigor tensions did not converge to a common time course until late in the transients. This result suggests that the proportion of myosin cross-bridges that can reattach into force-generating states depends on stress or strain in the filament lattice. A steady 10-mM concentration of Pi markedly decreased the transient reattachment phase after caged ATP photolysis. Pi also decreased the amplitude of stretch activation after step stretches applied in the presence of Ca2+ and ATP. Photolysis of caged Pi during stretch activation abruptly terminated the development of tension. These results are consistent with a linkage between Pi release and the steps leading to force production in the cross-bridge cycle.

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