scholarly journals Ultrastructural anatomy of nodes of Ranvier in the peripheral nervous system as revealed by STED microscopy

2016 ◽  
Vol 114 (2) ◽  
pp. E191-E199 ◽  
Author(s):  
Elisa D’Este ◽  
Dirk Kamin ◽  
Francisco Balzarotti ◽  
Stefan W. Hell
Keyword(s):  
Nerve Fibers ◽  
Cytoskeletal Proteins ◽  
Stimulated Emission ◽  
Nodes Of Ranvier ◽  
One Dimensional ◽  
Superresolution Microscopy ◽  
Ankyrin G ◽  
Paranodal Junctions ◽  
The One ◽  
High Degree

We used stimulated emission depletion (STED) superresolution microscopy to analyze the nanoscale organization of 12 glial and axonal proteins at the nodes of Ranvier of teased sciatic nerve fibers. Cytoskeletal proteins of the axon (betaIV spectrin, ankyrin G) exhibit a high degree of one-dimensional longitudinal order at nodal gaps. In contrast, axonal and glial nodal adhesion molecules [neurofascin-186, neuron glial-related cell adhesion molecule (NrCAM)] can arrange in a more complex, 2D hexagonal-like lattice but still feature a ∼190-nm periodicity. Such a lattice-like organization is also found for glial actin. Sodium and potassium channels exhibit a one-dimensional periodicity, with the Nav channels appearing to have a lower degree of organization. At paranodes, both axonal proteins (betaII spectrin, Caspr) and glial proteins (neurofascin-155, ankyrin B) form periodic quasi–one-dimensional arrangements, with a high degree of interdependence between the position of the axonal and the glial proteins. The results indicate the presence of mechanisms that finely align the cytoskeleton of the axon with the one of the Schwann cells, both at paranodal junctions (with myelin loops) and at nodal gaps (with microvilli). Taken together, our observations reveal the importance of the lateral organization of proteins at the nodes of Ranvier and pave the way for deeper investigations of the molecular ultrastructural mechanisms involved in action potential propagation, the formation of the nodes, axon–glia interactions, and demyelination diseases.

scholarly journals Nodes of Ranvier and axon initial segments are ankyrin G–dependent domains that assemble by distinct mechanisms

2007 ◽  
Vol 177 (5) ◽  
pp. 857-870 ◽  
Author(s):  
Yulia Dzhashiashvili ◽  
Yanqing Zhang ◽  
Jolanta Galinska ◽  
Isabel Lam ◽  
Martin Grumet ◽  
...  
Keyword(s):  
Schwann Cells ◽  
Sodium Channels ◽  
Cytoskeletal Proteins ◽  
Action Potential Generation ◽  
Potential Generation ◽  
Nodes Of Ranvier ◽  
Ankyrin G ◽  
Sites Of Action ◽  
Axon Initial Segments ◽  
Inside Out

Axon initial segments (AISs) and nodes of Ranvier are sites of action potential generation and propagation, respectively. Both domains are enriched in sodium channels complexed with adhesion molecules (neurofascin [NF] 186 and NrCAM) and cytoskeletal proteins (ankyrin G and βIV spectrin). We show that the AIS and peripheral nervous system (PNS) nodes both require ankyrin G but assemble by distinct mechanisms. The AIS is intrinsically specified; it forms independent of NF186, which is targeted to this site via intracellular interactions that require ankyrin G. In contrast, NF186 is targeted to the node, and independently cleared from the internode, by interactions of its ectodomain with myelinating Schwann cells. NF186 is critical for and initiates PNS node assembly by recruiting ankyrin G, which is required for the localization of sodium channels and the entire nodal complex. Thus, initial segments assemble from the inside out driven by the intrinsic accumulation of ankyrin G, whereas PNS nodes assemble from the outside in, specified by Schwann cells, which direct the NF186-dependent recruitment of ankyrin G.

Expression of intermediate filament proteins during development of Xenopus laevis. II. Identification and molecular characterization of desmin

Development ◽  
1989 ◽  
Vol 105 (2) ◽  
pp. 299-307 ◽  
Author(s):  
H. Herrmann ◽  
B. Fouquet ◽  
W.W. Franke
Keyword(s):  
Xenopus Laevis ◽  
Time Course ◽  
Mammalian Species ◽  
Sequence Divergence ◽  
Cytoskeletal Proteins ◽  
Similar Degree ◽  
Intermediate Filament Proteins ◽  
Muscle Tissues ◽  
The One ◽  
High Degree

During embryogenesis of avian and mammalian species the formation of intermediate filaments (IFs) containing desmin is characteristic for myogenesis. In view of important differences of patterns of IF protein expression in embryogenic pathways of amphibia on the one hand and birds and mammals on the other, we have decided to study the expression of desmin during early embryogenesis of Xenopus laevis by cDNA hybridization and antibody reactions. Here we describe the isolation of a cDNA clone encoding Xenopus desmin and the deduced amino acid sequence (458 residues; Mr 52,800) which displays a very high degree of conservation during vertebrate evolution from Xenopus to chicken and hamster, with a similar degree of sequence divergence between all three species compared. In addition, we have noted, by both cDNA-hybrid-selection-translation and immunoblotting of cytoskeletal proteins a second desmin-related polypeptide of Mr approximately 49,000. RNA (Northern) blot analyses show the occurrence of three different desmin mRNAs (1.9, 2.6 and 3.0 kb) which seem to represent different polyadenylation sites, displaying quantitative differences in different kinds of muscle tissues. During embryogenesis, desmin mRNA has first been detected in stage-14 embryos and then increases drastically to high levels at stage 18 and thereafter. Immunofluorescence microscopy using desmin-specific antibodies shows that this synthesis of desmin is restricted to somite tissue. The embryonic time course of synthesis of desmin and desmin mRNA is discussed in relation to those of other muscle proteins.

The One-Dimensional LTSN Solution In a Slab With High Degree of Quadrature

1999 ◽  
Vol 26 (10) ◽  
pp. 925-934 ◽  
Author(s):  
Segatto C. F. ◽  
Vilhena M. T ◽  
Gomes M. G.
Keyword(s):  
One Dimensional ◽  
The One ◽  
High Degree

Exploring the Multidimensional Facets of Authoritarianism: Authoritarian Aggression and Social Dominance Orientation

2008 ◽  
Vol 67 (1) ◽  
pp. 51-60 ◽  
Author(s):  
Stefano Passini
Keyword(s):  
Social Dominance ◽  
Factor Model ◽  
Three Dimensional ◽  
Social Dominance Orientation ◽  
Model Fit ◽  
Regression Analyses ◽  
One Dimensional ◽  
Confirmatory Factor ◽  
The One ◽  
Better Than

The relation between authoritarianism and social dominance orientation was analyzed, with authoritarianism measured using a three-dimensional scale. The implicit multidimensional structure (authoritarian submission, conventionalism, authoritarian aggression) of Altemeyer’s (1981, 1988) conceptualization of authoritarianism is inconsistent with its one-dimensional methodological operationalization. The dimensionality of authoritarianism was investigated using confirmatory factor analysis in a sample of 713 university students. As hypothesized, the three-factor model fit the data significantly better than the one-factor model. Regression analyses revealed that only authoritarian aggression was related to social dominance orientation. That is, only intolerance of deviance was related to high social dominance, whereas submissiveness was not.

Adiabatic large polarons in anisotropic molecular crystals

2011 ◽  
Vol 35 (1) ◽  
pp. 15-27
Author(s):  
Zoran Ivić ◽  
Željko Pržulj
Keyword(s):  
Energy Transfer ◽  
Effective Mass ◽  
Molecular Crystals ◽  
Single Chain ◽  
Proper Understanding ◽  
One Dimensional ◽  
Interchain Coupling ◽  
Large Polaron ◽  
The One

Adiabatic large polarons in anisotropic molecular crystals We study the large polaron whose motion is confined to a single chain in a system composed of the collection of parallel molecular chains embedded in threedimensional lattice. It is found that the interchain coupling has a significant impact on the large polaron characteristics. In particular, its radius is quite larger while its effective mass is considerably lighter than that estimated within the one-dimensional models. We believe that our findings should be taken into account for the proper understanding of the possible role of large polarons in the charge and energy transfer in quasi-one-dimensional substances.

El Prestige: comparativa de los regímenes internacionales de responsabilidad civil

2019 ◽  
Vol 37 (3) ◽  
pp. 31
Author(s):  
Raquel Fernández González ◽  
Marcos Íñigo Pérez Pérez
Keyword(s):  
Institutional Economics ◽  
Geographical Area ◽  
New Institutional Economics ◽  
Rigorous Analysis ◽  
Judicial Process ◽  
Main Research ◽  
Civil Responsibility ◽  
The One ◽  
High Degree ◽  
The Prestige

The return of institutions to the main research agenda has highlighted the importance of rules in economic analysis. The New Institutional Economics has allowed a better understanding of the case studies that concern different areas of knowledge, also the one concerning the management of natural resources. In this article, the institutional analysis focuses on the maritime domain, where two large civil liability regimes for pollution coexist (OPA 90-IMO), each in a different geographical area (United States - Europe). Therefore, a comparative analysis is made between the two large regimes of civil responsibility assignment applying them to the Prestige catastrophe. In this way, the allocation and distribution of responsibilities in the investigation and subsequent judicial process of the Prestige is compared with an alternative scenario in which the applicable compensation instruments are governed by the provisions of the Oil Polution Act of 1990 (OPA 90), in order to establish a rigorous analysis on the effects that the different norms can have in the same scenario. In the comparative established in the case of the Prestige, where the responsibilities were solved very slowly in a judicial process with high transaction costs, the application of rules governed by the OPA 90 would not count with such a high degree of imperfection. This is so, since by applying the preponderance of the evidence existing in OPA 90 there would be no mitigation for the presumed culprits. On the other hand, the agents involved in the sinking would not be limited only to the owner, but also that operators or shipowners would be responsible as well. In addition, the amount of compensation would increase when counting in the damage count the personal damages, the taxes without perceiving and the ecological damage caused in a broad sense, damages not computable in the IMO.

Sign in / Sign up

Export Citation Format

Share Document