scholarly journals Cells Connected by Tiny Tunnels

2004 ◽  
Vol 12 (5) ◽  
pp. 3-7
Author(s):  
Stephen W. Carmichael
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Wheat Germ ◽  
Cultured Cells ◽  
Cell Communication ◽  
Tunneling Nanotubes ◽  
Pheochromocytoma Cells ◽  
Intracellular Communication ◽  
Transmission Electron ◽  
Multicellular Organisms

Intracellular communication is imperative for multicellular organisms. Such devices as synapses and gap junctions have been recognized for decades. Now Amin Rustom, Raiser Saffrich, Ivanka Markovic, Paul Walther, and Hans-Hermann Gerdes have described a new model of cell-to-cell communication.While looking at PC12 (rat pheochromocytoma) cells in the presence of fluorescently labeled wheat germ agglutinin, Rustom et al. observed relatively long connections extending between cells. These structures were 50 to 200 nm in diameter and up to several cell diameters in length and were named tunneling nanotubes (TNTs). TNTs were subsequently found connecting cultured cells from other lines. They were consistently positioned along the smallest distance between the cells, did not contact the substrate, and occasionally were branched. TNTs immunostained positive for actin, but did not contain microtubules. Scanning and transmission electron microscopy definitively established that a TNT represented a seamless continuity of the plasma membrane from one cell to another.

scholarly journals Imaging heterostructured quantum dots in cultured cells with epifluorescence and transmission electron microscopy

2011 ◽  
Author(s):  
Erin M. Rivera ◽  
Casilda Trujillo Provencio ◽  
Andrea Steinbrueck ◽  
Pawan Rastogi ◽  
Allison Dennis ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Quantum Dots ◽  
Cultured Cells ◽  
Transmission Electron

scholarly journals Fluorescence and electron microscopy to visualize the intracellular fate of nanoparticles for drug delivery

2016 ◽  
Vol 60 (2) ◽  
Author(s):  
M. Costanzo ◽  
F. Carton ◽  
A. Marengo ◽  
G. Berlier ◽  
B. Stella ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Drug Delivery ◽  
Transmission Electron Microscopy ◽  
Cultured Cells ◽  
Cell System ◽  
Functional Relationships ◽  
Cell Internalization ◽  
Transmission Electron ◽  
Intracellular Fate

<p>In order to design valid protocols for drug release <em>via</em> nanocarriers, it is essential to know the mechanisms of cell internalization, the interactions with organelles, and the intracellular permanence and degradation of nanoparticles (NPs) as well as the possible cell alteration or damage induced. In the present study, the intracellular fate of liposomes, polymeric NPs and mesoporous silica NPs (MSN) has been investigated in an <em>in vitro</em> cell system by fluorescence and transmission electron microscopy. The tested nanocarriers proved to be characterized by specific interactions with the cell: liposomes enter the cells probably by fusion with the plasma membrane and undergo rapid cytoplasmic degradation; polymeric NPs are internalized by endocytosis, occur in the cytoplasm both enclosed in endosomes and free in the cytosol, and then undergo massive degradation by lysosome action; MSN are internalized by both endocytosis and phagocytosis, and persist in the cytoplasm enclosed in vacuoles. No one of the tested nanocarriers was found to enter the nucleus. The exposure to the different nanocarriers did not increase cell death; only liposomes induced a reduction of cell population after long incubation times, probably due to cell overloading. No subcellular damage was observed to be induced by polymeric NPs and MSN, whereas transmission electron microscopy revealed cytoplasm alterations in liposome-treated cells. This important information on the structural and functional relationships between nanocarriers designed for drug delivery and cultured cells further proves the crucial role of microscopy techniques in nanotechnology.</p>

scholarly journals Pseudorabies Virus US3-Induced Tunneling Nanotubes Contain Stabilized Microtubules, Interact with Neighboring Cells via Cadherins, and Allow Intercellular Molecular Communication

2017 ◽  
Vol 91 (19) ◽  
Author(s):  
Robert J. J. Jansens ◽  
Wim Van den Broeck ◽  
Steffi De Pelsmaeker ◽  
Jochen A. S. Lamote ◽  
Cliff Van Waesberghe ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Protein Kinase ◽  
Contact Area ◽  
Intercellular Communication ◽  
Beta Catenin ◽  
Virus Spread ◽  
Tunneling Nanotubes ◽  
Long Distance ◽  
Transmission Electron

ABSTRACT Tunneling nanotubes (TNTs) are long bridge-like structures that connect eukaryotic cells and mediate intercellular communication. We found earlier that the conserved alphaherpesvirus US3 protein kinase induces long cell projections that contact distant cells and promote intercellular virus spread. In this report, we show that the US3-induced cell projections constitute TNTs. In addition, we report that US3-induced TNTs mediate intercellular transport of information (e.g., green fluorescent protein [GFP]) in the absence of other viral proteins. US3-induced TNTs are remarkably stable compared to most TNTs described in the literature. In line with this, US3-induced TNTs were found to contain stabilized (acetylated and detyrosinated) microtubules. Transmission electron microscopy showed that virus particles are individually transported in membrane-bound vesicles in US3-induced TNTs and are released along the TNT and at the contact area between a TNT and the adjacent cell. Contact between US3-induced TNTs and acceptor cells is very stable, which correlated with a marked enrichment in adherens junction components beta-catenin and E-cadherin at the contact area. These data provide new structural insights into US3-induced TNTs and how they may contribute to intercellular communication and alphaherpesvirus spread. IMPORTANCE Tunneling nanotubes (TNT) represent an important and yet still poorly understood mode of long-distance intercellular communication. We and others reported earlier that the conserved alphaherpesvirus US3 protein kinase induces long cellular protrusions in infected and transfected cells. Here, we show that US3-induced cell projections constitute TNTs, based on structural properties and transport of biomolecules. In addition, we report on different particular characteristics of US3-induced TNTs that help to explain their remarkable stability compared to physiological TNTs. In addition, transmission electron microscopy assays indicate that, in infected cells, virions travel in the US3-induced TNTs in membranous transport vesicles and leave the TNT via exocytosis. These data generate new fundamental insights into the biology of (US3-induced) TNTs and into how they may contribute to intercellular virus spread and communication.

scholarly journals Pitfalls of immunogold labeling: analysis by light microscopy, transmission electron microscopy, and photoelectron microscopy.

1987 ◽  
Vol 35 (8) ◽  
pp. 843-853 ◽  
Author(s):  
G B Birrell ◽  
K K Hedberg ◽  
O H Griffith
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Light Microscopy ◽  
Tannic Acid ◽  
Cultured Cells ◽  
Immunogold Labeling ◽  
Fish Gelatin ◽  
Nonspecific Binding ◽  
Gold Particles ◽  
Transmission Electron

The immunogold method is widely used to localize, identify, and distinguish cellular antigens. There are, however, some pitfalls that can lead to nonspecific binding, particularly in cytoskeletal studies with gold probes prepared from small gold particles. We present a list of suggestions for minimizing nonspecific binding, with particular attention to two problems identified in this study. First, we find that the method used to prepare the colloidal gold particles affects the degree of nonspecific binding. Second, the standard BSA-stabilized small gold probes evidently possess exposed regions that bind to the proteins of cytoskeletal preparations. This was investigated in whole-mount cytoskeletal preparations of cultured cells by use of light microscopy, transmission electron microscopy, and photoelectron microscopy of silver-enhanced specimens. Gold probes were made from approximately 5-nm particles generated by reduction of HAuCl4 with three different reducing agents: white phosphorus, sodium borohydride, and citrate-tannic acid. All three preparations stabilized in the conventional way showed significant levels of nonspecific binding, which was highest with citrate-tannic acid. This problem was largely solved with all three types of probes by including fish gelatin in the probe buffer, by substituting fish gelatin for the BSA stabilizer used to prepare the probes, or by pre-adsorption methods. Application of these techniques resulted in clear immunogold labeling patterns with minimal nonspecific background.

Correlated scanning and transmission electron microscopy of Naegleria fowleri amoebastomes

1984 ◽  
Vol 42 ◽  
pp. 310-311
Author(s):  
T. B. Cole ◽  
R.A. Bruner ◽  
D.T. John
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cultured Cells ◽  
Yeast Cells ◽  
Naegleria Fowleri ◽  
Transmission Electron ◽  
Mammalian Cell Cultures ◽  
Nægleria Fowleri ◽  
Amoebic Meningoencephalitis ◽  
Fowleri Trophozoite

Naegleria fowleri is a free-living amoeboflagellate that is the causative agent of primary amoebic meningoencephalitis (PAM) in humans and is also cytopathogenic for established mammalian cell cultures. Scanning electron microscopy has shown that the focal ingestion of cultured cells is mediated by a sucker-like structure found on this amoeba. Another report also describes well-organized sucker-like structures called amoebastomes. In this report, we will correlate scanning (SEM) and transmission electron microscopy (TEM) to demonstrate the morphology and the application of the amoebastome of the invasive N. fowleri trophozoite.Isolates of N. fowleri amoebae were grown at 30°C with Nelson medium in standard round 35x10mm plastic petri dishes. Cultured yeast cells were washed in amoeba saline and added to the amoebic cultures 3 hr prior to fixation. At 72 hr of culture age, the amoebic cultures with the added live yeast cells, were carefully rinsed with amoeba saline and fixed for 1 hr at room temperature (23°C).

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