Nanophysiology of Cells, Channels and Nuclear Pores

2011 ◽  
pp. 117-144
Author(s):  
Hermann Schillers ◽  
Hans Oberleithner ◽  
Victor Shahin
Keyword(s):  
Nuclear Pores

The Formation, Structure, Distribution and Frequency of Nuclear Pores

1971 ◽  
Vol 29 ◽  
pp. 518-519
Author(s):  
G. G. Maul
Keyword(s):  
Nuclear Pore Complex ◽  
Nuclear Membrane ◽  
Dynamic Structure ◽  
Nuclear Pore ◽  
Nuclear Pores ◽  
Filter Function ◽  
Etching Technique ◽  
Selective Filter ◽  
Membranous Part

The chromatin of eukaryotic cells is separated from the cytoplasm by a double membrane. One obvious structural specialization of the nuclear membrane is the presence of pores which have been implicated to facilitate the selective nucleocytoplasmic exchange of a variety of large molecules. Thus, the function of nuclear pores has mainly been regarded to be a passive one. Non-membranous diaphragms, radiating fibers, central rings, and other pore-associated structures were thought to play a role in the selective filter function of the nuclear pore complex. Evidence will be presented that suggests that the nuclear pore is a dynamic structure which is non-randomly distributed and can be formed during interphase, and that a close relationship exists between chromatin and the membranous part of the nuclear pore complex.Octagonality of the nuclear pore complex has been confirmed by a variety of techniques. Using the freeze-etching technique, it was possible to show that the membranous part of the pore complex has an eight-sided outline in human melanoma cells in vitro. Fibers which traverse the pore proper at its corners are continuous and indistinguishable from chromatin at the nucleoplasmic side, as seen in conventionally fixed and sectioned material. Chromatin can be seen in octagonal outline if serial sections are analyzed which are parallel but do not include nuclear membranes (Fig. 1). It is concluded that the shape of the pore rim is due to fibrous material traversing the pore, and may not have any functional significance. In many pores one can recognize a central ring with eight fibers radiating to the corners of the pore rim. Such a structural arrangement is also found to connect eight ribosomes at the nuclear membrane.

High-voltage cytochemistry for three-dimensional observation of nuclei and calculation of total numbers of nuclear pores in retinal Mueller glia

1990 ◽  
Vol 48 (3) ◽  
pp. 956-957
Author(s):  
H. Ishigooka ◽  
S. Ueno ◽  
L.M. Hjelmeland ◽  
M.B. Landers ◽  
K. Ogawa
Keyword(s):  
Nuclear Envelope ◽  
High Voltage ◽  
Three Dimensional ◽  
Reaction Medium ◽  
Nuclear Pores ◽  
High Voltage Electron Microscopy ◽  
Voltage Electron ◽  
High Voltage Electron ◽  
G6pase Activity ◽  
Mueller Glia

Introduction: We have demonstrated that Glucose-6-phosphatase (G6Pase) activity is localized to the endoplasmic reticulum and nuclear envelope of Mueller glia in the normal and pathological guinea pig retina. Using a combination of this cytochemical technique and high voltage electron microscopy, the distribution of nuclear pores could be clearly observed on the nuclear envelope of Mueller glia because of their anatomical lack of reaction products. This technique was developed to study the three-dimensional structure of nuclei and to calculate total numbers of nuclear pores utilizing a computer graphic analysis system in the normal and pathological retina.Materials and methods: Normal and photocoagulated retina of pigmented adult guinea pigs were perfused with a cold mixture of 0.25% glutaraldehyde and 2% paraformaldehyde in 0.1M cacodylate buffer, and the enucleated globes were hemisected and immersed in the same fixative for 30 min. After sectioning and incubation in the reaction medium for the detection of G6Pase activity by the method of Wachstein-Meisel, the sections were postfixed, dehydrated and embedded in Spurr’s epoxy resin. Serial thick sections (1.0um) were prepared for the observation by a Hitachi high voltage electron microscope (H 1250-M) with an accelerating voltage of 1000 Kv. and pictures were analyzed and three-dimensionally reconstructed by TRI (RATOC Co., Ltd.).

ATP-Induced Shape Change of Nuclear Pores Visualized with the Atomic Force Microscope

1998 ◽  
Vol 163 (2) ◽  
pp. 129-136 ◽  
Author(s):  
A., Rakowska ◽  
T. Danker ◽  
S.W. Schneider ◽  
H. Oberleithner
Keyword(s):  
Atomic Force Microscope ◽  
Shape Change ◽  
Nuclear Pores ◽  
Atomic Force

scholarly journals β-Catenin Shows an Overlapping Sequence Requirement but Distinct Molecular Interactions for Its Bidirectional Passage through Nuclear Pores

2004 ◽  
Vol 279 (32) ◽  
pp. 34038-34047 ◽  
Author(s):  
Makiko Koike ◽  
Shingo Kose ◽  
Maiko Furuta ◽  
Naoko Taniguchi ◽  
Fumihiko Yokoya ◽  
...  
Keyword(s):  
Molecular Interactions ◽  
Nuclear Pores

Structural and biochemical aspects of liver cell nuclear organization in normal and scalded rats

1984 ◽  
Vol 71 (1) ◽  
pp. 75-93
Author(s):  
L. Sevaljevic ◽  
M. Petrovic ◽  
G. Poznanovic ◽  
A. Skaro ◽  
D. Pantelic
Keyword(s):  
Nuclear Structure ◽  
Thermal Injury ◽  
Nuclear Organization ◽  
Chromatin Condensation ◽  
Metal Chelators ◽  
Nuclear Pores ◽  
Dna And Rna ◽  
Liver Nuclei ◽  
Minimal Residual

The response of rat liver nuclei to thermal injury was studied at the ultrastructural and biochemical levels using nuclei isolated in the presence of either Mg2+ or polyamines and metal chelators. The extent of chromatin condensation, as revealed by electron microscopy, increased in the order: nuclei in situ, Mg-stabilized nuclei, polyamine-stabilized nuclei. In addition, we observed that thermal injury caused an increase in the number of nuclear pores, an enlargement of nucleoli and an accumulation of ribonucleoprotein material. Along with this, greater amounts of protein, DNA and RNA were retained in nuclei from scalded rats. The salt-resistant residue from Mg-stabilized nuclei was a spherical proteinaceous structure of the nuclear matrix, whereas that of the polyamine-stabilized nuclei was amorphous and deprived of three major constituents of the spherical matrix, the 60–70 X 10(3) Mr lamina proteins. However, exposure of the polyamine-stabilized nuclei to Ca2+ and Mg2+ rendered the 60–70 X 10(3) Mr proteins salt-insoluble and thus enabled the extraction of a spherical residual nuclear structure. This structure was highly enriched in DNA, RNA and non-histone proteins and, hence, more like dehistonized nuclei than the minimal residual nuclear structure. It retained 70% of DNA in the controls but virtually all the DNA in scalded rats. This difference was interpreted to reflect activation-related changes in chromatin organization.

scholarly journals Nuclear pores at the core

2012 ◽  
Vol 13 (3) ◽  
pp. 151-151
Author(s):  
Mary Muers
Keyword(s):  
Nuclear Pores ◽  
The Core
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