Electron microscopic images suggest both ends of caldesmon interact with actin filaments

1993 ◽  
Vol 14 (1) ◽  
pp. 54-64 ◽  
Author(s):  
Katsuhide Mabuchi ◽  
Jim J.-C. Lin ◽  
C.-L. Albert Wang
Keyword(s):  
Actin Filaments ◽  
Electron Microscopic ◽  
Microscopic Images

An Efficient Adaptive Algorithm for Electron Microscopic Image Enhancement and Feature Extraction

2019 ◽  
Vol 9 (1) ◽  
pp. 1-16
Author(s):  
Vivek Arya ◽  
Vipul Sharma ◽  
Garima Arya
Keyword(s):  
Feature Extraction ◽  
Contrast Enhancement ◽  
Block Size ◽  
Sigmoid Function ◽  
Microscopic Image ◽  
Electron Microscopic ◽  
Microscopic Images ◽  
Electron Microscopic Image ◽  
Block Based

In this article, a block-based adaptive contrast enhancement algorithm has been proposed, which uses a modified sigmoid function for the enhancement and features extraction of electron microscopic images. The algorithm is based on a modified sigmoid function that adapts according to the input microscopic image statistics. For feature extraction, the contrast of the image is very important and authentic property by which this article enhances the visual quality of the image. In this work, for better contrast enhancement of image, a block based on input value, combined with a modified sigmoid function that is used as contrast enhancer provides better EMF values for a smaller block size. It provides localized contrast enhancement effects adaptively which is not possible using other existing techniques. Simulation and experimental results demonstrate that the proposed technique gives better results compared to other existing techniques when applied to electron microscopic images. After the enhancement of microscopic images of actinomycetes, various important features are shown, like coil or spiral, long filament, spore and rod shape structures. The proposed algorithm works efficiently for different dark and bright microscopic images.

scholarly journals Monitoring and Determining Mitochondrial Network Parameters in Live Lung Cancer Cells

2019 ◽  
Vol 8 (10) ◽  
pp. 1723
Author(s):  
Tamara Mirzapoiazova ◽  
Haiqing Li ◽  
Anusha Nathan ◽  
Saumya Srivstava ◽  
Mohd W. Nasser ◽  
...  
Keyword(s):  
Lung Cancer ◽  
3D Reconstruction ◽  
Cellular Response ◽  
Mitochondrial Dynamics ◽  
Confocal Imaging ◽  
Live Cells ◽  
Mitochondrial Morphology ◽  
Electron Microscopic ◽  
Microscopic Images ◽  
Network Parameters

Mitochondria are dynamic organelles that constantly fuse and divide, forming dynamic tubular networks. Abnormalities in mitochondrial dynamics and morphology are linked to diverse pathological states, including cancer. Thus, alterations in mitochondrial parameters could indicate early events of disease manifestation or progression. However, finding reliable and quantitative tools for monitoring mitochondria and determining the network parameters, particularly in live cells, has proven challenging. Here, we present a 2D confocal imaging-based approach that combines automatic mitochondrial morphology and dynamics analysis with fractal analysis in live small cell lung cancer (SCLC) cells. We chose SCLC cells as a test case since they typically have very little cytoplasm, but an abundance of smaller mitochondria compared to many of the commonly used cell types. The 2D confocal images provide a robust approach to quantitatively measure mitochondrial dynamics and morphology in live cells. Furthermore, we performed 3D reconstruction of electron microscopic images and show that the 3D reconstruction of the electron microscopic images complements this approach to yield better resolution. The data also suggest that the parameters of mitochondrial dynamics and fractal dimensions are sensitive indicators of cellular response to subtle perturbations, and hence, may serve as potential markers of drug response in lung cancer.

scholarly journals Cytoskeletal reorganization of human platelets after stimulation revealed by the quick-freeze deep-etch technique.

1987 ◽  
Vol 105 (4) ◽  
pp. 1771-1780 ◽  
Author(s):  
T Nakata ◽  
N Hirokawa
Keyword(s):  
Actin Filaments ◽  
Plasma Membranes ◽  
Human Platelets ◽  
Electron Microscopic Level ◽  
Immunocytochemical Study ◽  
Cytoskeletal Reorganization ◽  
Electron Microscopic ◽  
Activated Platelets ◽  
Mixed Polarity ◽  
Cross Bridges

We studied the cytoskeletal reorganization of saponized human platelets after stimulation by using the quick-freeze deep-etch technique, and examined the localization of myosin in thrombin-treated platelets by immunocytochemistry at the electron microscopic level. In unstimulated saponized platelets we observed cross-bridges between: adjoining microtubules, adjoining actin filaments, microtubules and actin filaments, and actin filaments and plasma membranes. After activation with 1 U/ml thrombin for 3 min, massive arrays of actin filaments with mixed polarity were found in the cytoplasm. Two types of cross-bridges between actin filaments were observed: short cross-bridges (11 +/- 2 nm), just like those observed in the resting platelets, and longer ones (22 +/- 3 nm). Actin filaments were linked with the plasma membrane via fine short filaments and sometimes ended on the membrane. Actin filaments and microtubules frequently ran close to the membrane organelles. We also found that actin filaments were associated by end-on attachments with some organelles. Decoration with subfragment 1 of myosin revealed that all the actin filaments associated end-on with the membrane pointed away in their polarity. Immunocytochemical study revealed that myosin was present in the saponin-extracted cytoskeleton after activation and that myosin was localized on the filamentous network. The results suggest that myosin forms a gel with actin filaments in activated platelets. Close associations between actin filaments and organelles in activated platelets suggests that contraction of this actomyosin gel could bring about the observed centralization of organelles.

scholarly journals Biotinylphallotoxins: preparation and use as actin probes.

1989 ◽  
Vol 37 (7) ◽  
pp. 1035-1045 ◽  
Author(s):  
H Faulstich ◽  
S Zobeley ◽  
U Bentrup ◽  
B M Jockusch
Keyword(s):  
Actin Filaments ◽  
Ultrastructural Level ◽  
Microscopic Level ◽  
Electron Microscopic Level ◽  
Electron Microscopic ◽  
Permeabilized Cells ◽  
High Affinity ◽  
Double Label ◽  
The One

We describe the synthesis of four phalloidin derivatives conjugated with biotin. An aminomethyldithiolane derivative of ketophalloidin was used as a reactive starter compound, and biotin residues were coupled to this molecule either directly, separated by spacer chains comprised of one or two glycyl residues, or of a 12-atom long chain constructed from succinic acid and hexamethylendiamine. Although all products still displayed a high affinity for F-actin, as seen in competition experiments with [3H]-demethylphalloidin, only the one with the longest spacer (BHPP) showed specific and high-affinity decoration of actin filaments in permeabilized cells, in conjunction with FITC-coupled avidin and fluorescence microscopy. Combined with gold-streptavidin, BHPP decorated the actin filament system at the light and electron microscopic level faithfully and with satisfactory density. Actin filaments polymerized in vitro from purified protein were not as densely labeled as had been expected. However, in all these experiments the new phalloidin probe, when combined with avidin or streptavidin, yielded clear and highly specific labeling of F-actin. Therefore, this system is useful to identify and localize actin unambiguously in microfilaments, independent of actin antibodies, and should facilitate double-label experiments on cytoskeletal components at the ultrastructural level.

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