What microscopic studies of confronting cisternae and annulate lamellae reveal about their similarities and differences

1995 ◽  
Vol 53 ◽  
pp. 926-927
Author(s):  
John R. Palisano ◽  
Karen S. Renzaglia
Keyword(s):  
Electron Microscopy ◽  
Tumor Cells ◽  
Mitotic Cell ◽  
Annulate Lamellae ◽  
Proliferative Stage ◽  
Dividing Cells ◽  
Microscopic Studies ◽  
Similarities And Differences ◽  
And Function

Knowledge of the origin and function of confronting cisternae (CC) and annulate lamellae (AL) has been limited because they are so infrequently observed. CC were first described by Porter in 1955 and have since been observed in a variety of rapidly proliferating tumor cells and selected fetal tissues. AL were first reported in 1952 by McCullough in sea urchin eggs. Although AL have since been observed in a variety of cells, they have been predominately found in oocytes, spermatocytes, and tumor cells. A microscopic study was initiated to gain a better understanding of the origin and role of these two membranous organelles that are frequently found in rapidly dividing cells that lose the ability to express these organelles once their rapid proliferative stage ceases. Because it has proven difficult to interpret the flow of membrane in the mitotic cell by electron microscopy alone, data obtained by electron microscopy was correlated with fluorescence microscopy wherever possible.

Scanning electron microscopic study of collagen fibrillogenesis and extracellular compartmentalization in the chick embryo tendon

1986 ◽  
Vol 44 ◽  
pp. 208-209
Author(s):  
Grace C.H. Yang
Keyword(s):  
Chick Embryo ◽  
Extracellular Space ◽  
Fibroblast Cell ◽  
Collagen Fibrils ◽  
Electron Microscopic ◽  
Voltage Electron ◽  
Scanning Electron Microscopic Study ◽  
Microscopic Studies ◽  
And Function

The size and organization of collagen fibrils in the extracellular matrix is an important determinant of tissue structure and function. The synthesis and deposition of collagen involves multiple steps which begin within the cell and continue in the extracellular space. High-voltage electron microscopic studies of the chick embryo cornea and tendon suggested that the extracellular space is compartmentalized by the fibroblasts for the regulation of collagen fibril, bundle, and tissue specific macroaggregate formation. The purpose of this study is to gather direct evidence regarding the association of the fibroblast cell surface with newly formed collagen fibrils, and to define the role of the fibroblast in the control and the precise positioning of collagen fibrils, bundles, and macroaggregates during chick tendon development.

scholarly journals The Role of Extracellular Vesicles in Cancer: Cargo, Function, and Therapeutic Implications

Cells ◽  
2018 ◽  
Vol 7 (8) ◽  
pp. 93 ◽  
Author(s):  
James Jabalee ◽  
Rebecca Towle ◽  
Cathie Garnis
Keyword(s):  
Tumor Microenvironment ◽  
Tumor Cells ◽  
Extracellular Vesicles ◽  
Tumor Stroma ◽  
Therapeutic Implications ◽  
Membrane Bound ◽  
Immune Destruction ◽  
And Function ◽  
Cargo Molecule

Extracellular vesicles (EVs) are a heterogeneous collection of membrane-bound structures that play key roles in intercellular communication. EVs are potent regulators of tumorigenesis and function largely via the shuttling of cargo molecules (RNA, DNA, protein, etc.) among cancer cells and the cells of the tumor stroma. EV-based crosstalk can promote proliferation, shape the tumor microenvironment, enhance metastasis, and allow tumor cells to evade immune destruction. In many cases these functions have been linked to the presence of specific cargo molecules. Herein we will review various types of EV cargo molecule and their functional impacts in the context of oncology.

scholarly journals Morphological reassessment of the movable calcar of delphacid planthoppers (Hemiptera: Fulgoromorpha: Delphacidae)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Darya Markevich ◽  
Marcin Walczak ◽  
Oleg Borodin ◽  
Jacek Szwedo ◽  
Jolanta Brożek
Keyword(s):  
Electron Microscopy ◽  
Structure And Function ◽  
Number Of Teeth ◽  
Sensory Structures ◽  
Similarities And Differences ◽  
And Function

AbstractThis study presents the morphology of calcar in adult Delphacidae based on representatives of the genera Ugyops Guérin-Meneville, 1834, Notuchus Fennah, 1969 (Ugyopini), Asiraca Latreille, 1798 (Asiracini), Kelisia Fieber, 1866, (Kelisini), Stenocranus Fieber, 1866 (Stenocranini), Chloriona Fieber, 1866, Megadelphax Wagner, 1963, Muellerianella Wagner, 1963, Javesella Fennah, 1963, Conomelus Fieber, 1866, Euconomelus Haupt, 1929, Hyledelphax Vilbaste, 1968, Stiroma Fieber, 1866, Struebingianella Wagner, 1963 and Xanthodelphax Wagner, 1963 (Delphacini). We used SEM electron microscopy, to define seven types of calcar structure (Types 1, 2, 5, 6, 7, 8, and 9) based on combinations of characters including shape, number of teeth and differentiation of sensory structures in species from fifteen genera. Additionally, two other types (Types 3 and 4) were determined based on the calcar descriptions from previous studies. Similarities and differences in calcar structure and function were discussed and emerging relationships between planthopper species and their particular habitats were indicated.

Progress in ultrastructural and molecular analysis of the nuclear matrix

1992 ◽  
Vol 50 (1) ◽  
pp. 508-509
Author(s):  
Edward G. Fey
Keyword(s):  
Electron Microscopy ◽  
Nuclear Matrix ◽  
Structure And Function ◽  
Matrix Proteins ◽  
Rna Transcription ◽  
Nuclear Matrix Proteins ◽  
The Past ◽  
And Function

In the past few years, considerable advances have been made regarding the structure and function of the nuclear matrix. In the first half of this presentation, the field of nuclear matrix research will be summarized. Emphasis will be placed on those studies where molecular interactions are demonstrated in situ utilizing high resolution light and/or electron microscopy. Studies demonstrating the role of the nuclear matrix in DNA synthesis and replication, RNA transcription and processing, and the binding of matrix attachment regions to specific nuclear matrix proteins will be summarized.

scholarly journals Arsenic in Soils Affected by Mining: Microscopic Studies vs. Sequential Chemical Extraction

2020 ◽  
Vol 17 (22) ◽  
pp. 8426
Author(s):  
Jessica Álvarez-Quintana ◽  
Rodrigo Álvarez ◽  
Almudena Ordóñez
Keyword(s):  
Electron Microscopy ◽  
Residual Fraction ◽  
Chemical Extraction ◽  
Sequential Chemical Extraction ◽  
Transmission Electron ◽  
Microscopic Studies ◽  
Sequential Extraction Method ◽  
As Adsorption ◽  
Microscopic Techniques

Soil samples from three inactive mines, corresponding to different Arsenic-bearing mineralization types, were collected and studied. The aim was to determine the influence of mine wastes mineralogy/geochemistry and texture in As mobility and to compare results from sequential chemical extraction and microscopic techniques (optical and electron) at a grain scale. Arsenic in soils is found mainly associated to the residual fraction, indicating that mechanical As dispersion is mainly responsible for As soil pollution. The use of objective microscopic techniques (i.e., Scanning Electron Microscopy-Energy Dispersive Spectroscopy -SEM-EDS-, High Resolution Transmission Electron Microscopy -HR-TEM) has pointed out that the selected sequential extraction method overestimates the role of Mn amorphous oxy-hydroxides and organic matter in As retention while underestimating the mechanism of As adsorption onto clay particle surfaces.

scholarly journals The role of the integral membrane nucleoporins Ndc1p and Pom152p in nuclear pore complex assembly and function

2006 ◽  
Vol 173 (3) ◽  
pp. 361-371 ◽  
Author(s):  
Alexis S. Madrid ◽  
Joel Mancuso ◽  
W. Zacheus Cande ◽  
Karsten Weis
Keyword(s):  
Electron Microscopy ◽  
Saccharomyces Cerevisiae ◽  
Nuclear Envelope ◽  
Lipid Bilayers ◽  
Nuclear Pore Complex ◽  
Transmembrane Proteins ◽  
Nuclear Pore ◽  
Large Channel ◽  
And Function

The nuclear pore complex (NPC) is a large channel that spans the two lipid bilayers of the nuclear envelope and mediates transport events between the cytoplasm and the nucleus. Only a few NPC components are transmembrane proteins, and the role of these proteins in NPC function and assembly remains poorly understood. We investigate the function of the three integral membrane nucleoporins, which are Ndc1p, Pom152p, and Pom34p, in NPC assembly and transport in Saccharomyces cerevisiae. We find that Ndc1p is important for the correct localization of nuclear transport cargoes and of components of the NPC. However, the role of Ndc1p in NPC assembly is partially redundant with Pom152p, as cells lacking both of these proteins show enhanced NPC disruption. Electron microscopy studies reveal that the absence of Ndc1p and Pom152p results in aberrant pores that have enlarged diameters and lack proteinaceous material, leading to an increased diffusion between the cytoplasm and the nucleus.

Effects of Vinblastine on the Structure and Function of the Rat Exorbital Lacrimal Gland

1976 ◽  
Vol 34 ◽  
pp. 366-367
Author(s):  
Robert B. Kelly
Keyword(s):  
Electron Microscopy ◽  
Lacrimal Gland ◽  
Untreated Control ◽  
Acinar Cells ◽  
Structure And Function ◽  
Cytoplasmic Microtubules ◽  
And Function

Antimicrotubular agents such as vinblastine and colchicine have been used to assess the role of cytoplasmic microtubules in secretory processes (for review, see 1). The purpose of this study was to determine the effects of vinblastine on the structure and function of resting and pilocarpine- stimulated acinar cells of the rat exorbital lacrimal gland.Rats were divided into four groups: (a) untreated control; (b) vinblastine (4 mg/kg) treatment for 1 to 24 hours; (c) pilocarpine (20 mg/kg) treatment for 1 hour; and (d) vinblastine treatment for 1 hour, followed by pilocarpine treatment for 1 hour. Both drugs were administered via single intraperitoneal injections. The glands were fixed by perfusion and processed for electron microscopy.

Role of different domains in the self-association of rat nucleoporin p62

1994 ◽  
Vol 107 (2) ◽  
pp. 631-638
Author(s):  
F. Buss ◽  
H. Kent ◽  
M. Stewart ◽  
S.M. Bailer ◽  
J.A. Hanover
Keyword(s):  
Electron Microscopy ◽  
Association Studies ◽  
Coiled Coil ◽  
Small Region ◽  
C Terminus ◽  
Linear Chains ◽  
Beta Structure ◽  
Self Association ◽  
And Function

We have expressed rat nucleoporin p62 cDNA in Escherichia coli to obtain material for structural and self-association studies. Electron microscopy and circular dichroism spectroscopy are consistent with a rod-shaped molecule with an alpha-helical coiled-coil domain at its C terminus and a cross-beta structure at its N terminus, separated by a threonine-rich linker, which has a less-defined secondary structure. Electron microscopy and the solubility properties of fragments produced using thrombin and CNBr digestion indicate that p62 molecules associate to form linear chains and that a small region near the C terminus is an important determinant of assembly. This association may have important consequences for pore structure and function; for example, one way p62 could associate would be to form rings in nuclear pores that could function like barrel hoops.

scholarly journals The Role of Minor Pilins in Assembly and Function of the Competence Pilus of Streptococcus pneumoniae

2021 ◽  
Vol 11 ◽  
Author(s):  
Vitor Oliveira ◽  
Marie-Stephanie Aschtgen ◽  
Anke van Erp ◽  
Birgitta Henriques-Normark ◽  
Sandra Muschiol
Keyword(s):  
Electron Microscopy ◽  
Streptococcus Pneumoniae ◽  
Extracellular Dna ◽  
Genomic Plasticity ◽  
Protein Protein Interaction ◽  
Pilus Biogenesis ◽  
And Function ◽  
Natural Genetic Transformation ◽  
Pilus Assembly

The remarkable genomic plasticity of Streptococcus pneumoniae largely depends on its ability to undergo natural genetic transformation. To take up extracellular DNA, S. pneumoniae assembles competence pili composed of the major pilin ComGC. In addition to ComGC, four minor pilins ComGD, E, F, and G are expressed during bacterial competence, but their role in pilus biogenesis and transformation is unknown. Here, using a combination of protein-protein interaction assays we show that all four proteins can directly interact with each other. Pneumococcal ComGG stabilizes the minor pilin ComGD and ComGF and can interact with and stabilize the major pilin ComGC, thus, deletion of ComGG abolishes competence pilus assembly. We further demonstrate that minor pilins are present in sheared pili fractions and find ComGF to be incorporated along the competence pilus by immunofluorescence and electron microscopy. Finally, mutants of the invariant Glu5 residue (E5), ComGDE5A or ComGEE5A, but not ComGFE5A, were severely impaired in pilus formation and function. Together, our results suggest that ComGG, lacking E5, is essential for competence pilus assembly and function, and plays a central role in connecting the pneumococcal minor pilins to ComGC.

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