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  • 1
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    Polarity and velocity of sliding filaments: control of direction by actin and of speed by myosin (1990)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1990-07-27
    Description: Myosin filaments, which are responsible for a large repertoire of motile activities in muscle and nonmuscle cells, can translocate actin filaments both toward and away from their central bare zone. This bidirectional movement suggests that there is enough flexibility in the head portion of the tightly packed myosin molecules in the native myosin filaments to move actin filaments not only in the expected direction, but also in the direction opposite to that predicted by the regular structure of muscle--away from the center of the myosin filament.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sellers, J R -- Kachar, B -- New York, N.Y. -- Science. 1990 Jul 27;249(4967):406-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Molecular Cardiology, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2377894" target="_blank"〉PubMed〈/a〉
    Keywords: Actins/*physiology ; Animals ; *Bivalvia ; Chemistry, Physical ; Macromolecular Substances ; Muscle Contraction ; Muscles/physiology/*ultrastructure ; Myosins/*physiology ; Physicochemical Phenomena
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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  • 2
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    Rapid massive assembly of tight junction strands (1981)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1981-07-31
    Description: Incubation at 37 degrees C of excised rat prostate tissue results in massive proliferative assembly of new tight junction strands along the entire lengths of the lateral plasma membranes of the columnar epithelial cells. The new tight junction elements are assembled within 5 minutes and have an average length six times that of those present in the apical tight junction band. Massive assembly occurs in the presence of protein synthesis inhibitors (cycloheximide) or of metabolic uncouplers (dinitrophenol). Thus, proliferative assembly of tight junction strands involves molecular reorganization from a pool of preexisting, probably membrane-associated, components. The fascia occludens and some examples of experimentally induced tight junction proliferation may reflect the massive emergence of tight junction strands when tissue is subjected to diverse stressful conditions.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kachar, B -- Pinto da Silva, P -- New York, N.Y. -- Science. 1981 Jul 31;213(4507):541-4.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7244652" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cycloheximide/pharmacology ; Dinitrophenols/pharmacology ; Intercellular Junctions/drug effects/*physiology/ultrastructure ; Male ; Prostate/physiology/ultrastructure ; Rats
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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  • 3
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    Freeze-fracture cytochemistry: replicas of critical point-dried cells and tissues after fracture-label (1981)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1981-07-10
    Description: Applications of the new fracture-labeling techniques for the observation of cytochemical labels on platinum-carbon replicas are described. Frozen cells, embedded in a cross-linked protein matrix, and frozen tissues are fractured with a scalpel under liquid nitrogen, thawed, labeled, dehydrated by the critical point drying method, and replicated. This method allows direct, high-resolution, two-dimensional chemical and immunological characterization of the cellular membranes in situ, as well as detection of sites within cross-fractured cytoplasm and extracellular matrix.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉da Silva, P P -- Kachar, B -- Torrisi, M R -- Brown, C -- Parkison, C -- New York, N.Y. -- Science. 1981 Jul 10;213(4504):230-3.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7244630" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Antigens/analysis ; Cells/*ultrastructure ; Cytoplasmic Granules/ultrastructure ; Endoplasmic Reticulum/ultrastructure ; Erythrocytes/ultrastructure ; Freeze Fracturing/*methods ; Humans ; Indicators and Reagents ; Intracellular Membranes/ultrastructure ; Leukocytes/ultrastructure ; Microscopy, Electron/methods ; Pancreas/ultrastructure ; Pituitary Gland, Anterior/ultrastructure ; Platinum ; Rats
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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  • 4
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    Asymmetric illumination contrast: a method of image formation for video light microscopy (1985)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1985-02-15
    Description: Images with high resolution and exceptionally broad gray scale can be obtained by the application of video contrast enhancement to an optimized procedure for imaging transparent objects with oblique rays of illumination. This technique is simple to set up. A conventional microscope with a light source whose position can be adjusted and a video camera with controls for gain and black level are the only essential components. Features such as high resolution, optical sectioning, control of contrast, and operation under low light intensity make this technique preferable, in several instances, to currently used video microscopy techniques.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kachar, B -- New York, N.Y. -- Science. 1985 Feb 15;227(4688):766-8.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3969565" target="_blank"〉PubMed〈/a〉
    Keywords: Microscopy/*instrumentation ; Video Recording/*instrumentation
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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  • 5
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    Direct visualization of organelle movement along actin filaments dissociated from characean algae (1985)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1985-03-15
    Description: A system has been developed in which organelle transport can be studied without the influence of an organized cellular cytoplasm. Binding and continuous unidirectional movement of organelles along isolated cellular transport cables were directly visualized by video light microscopy after the dissociation of the cytoplasm of characean algae cells in a Ca2+-free buffer containing adenosine triphosphate. Individual organelles had more than one attachment site and moved at mean rates of 11.2 or 62.1 micrometers per second along multiple parallel pathways on each cable. Electron microscopy of these cables after direct freezing demonstrated that they consist of compact bundles of actin filaments. Under these conditions, characteristics of organelle movement should reflect directly the underlying molecular processes of binding and force generation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kachar, B -- New York, N.Y. -- Science. 1985 Mar 15;227(4692):1355-7.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/4038817" target="_blank"〉PubMed〈/a〉
    Keywords: Actins/*physiology ; Adenosine Triphosphate/metabolism ; Cytoplasm/physiology/ultrastructure ; Cytoskeleton/*physiology/ultrastructure ; Eukaryota/metabolism ; Microscopy, Electron ; Movement ; Organoids/*physiology/ultrastructure
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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  • 6
    Electronic Resource
    Electronic Resource
    Spontaneous vesicles (1984)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 106 (1984), S. 4279-4280 
    Details
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ja00327a044
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  • 7
    Electronic Resource
    Electronic Resource
    Modulation of tight junction morphology and permeability by an epithelial factor (1994)
    Springer
    The journal of membrane biology 139 (1994), S. 41-48 
    Details
    ISSN: 1432-1424
    Keywords: Tight junction ; Intercellular junctions ; Transepithelial permeability ; Transepithelial electrical resistance (TER) ; MDCK, A6, Caco-2 epithelial cell cultures
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract We report evidence of a factor secreted at the apical side of epithelial monolayers which modulates tight junction structure and permeability. This activity was detected within 4–7 days of conditioning of the apical medium by MDCK, A6 or Caco-2 epithelial cell lines cultured on permeable membranes in bipartite chambers. Apical conditioned medium (ACM), applied to the basolateral surface of a confluent monolayer, increased the transepithelial electrical resistance (TER), progressively reaching values 12–22% higher than the baseline within 5–10 min. After 40–60 min, the TER returned slowly to the basal value. This phenomenon was not observed either when using preheated ACM or the ACM filtrate obtained through a 30,000 MW cutoff membrane. The ACM maintained its activity even when applied to cell lines from different organs and species, as demonstrated when ACM from MDCK monolayers promoted an increase of 22% in the TER of Caco-2 cells. The increase of TER induced by the ACM treatment is accompanied by a change in the distribution of the number of tight junction strands, from an initial pattern, dominated mostly by junctions with one or two strands, to a new pattern after treatment dominated by junctions with two or three strands. Our results suggest the existence of a mechanism in epithelial cells that could signal leakage of apically secreted components to the basolateral side, thereby modulating the junction structure and permeability.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00232673
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  • 8
    Electronic Resource
    Electronic Resource
    Identification of Isoforms of G Proteins and PKC that Colocalize with Tight Junctions (1996)
    Springer
    The journal of membrane biology 149 (1996), S. 199-209 
    Details
    ISSN: 1432-1424
    Keywords: Key words: Tight junctions — PKC — G proteins — MDCK — Caco-2
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract. Recent evidence suggests that the formation and permeability of tight junctions are actively regulated by second-messenger-generating systems involving G proteins and protein kinase C (PKC). A possible specific target for these regulatory proteins is the tight junction protein ZO-1. An extensive immunocytochemical study was performed in cultured epithelial monolayers of MDCK and Caco-2 cells to identify which isoforms of G proteins and PKC are present at or near the zonula occludens complex. Antibodies against α-subunits of each one of the four major subfamilies were used for the localization of the G proteins. For the PKC localization, antibodies against eight different isoforms were used. In confluent monolayers, Gα12 and PKC ζ, were the only isoforms of these proteins present at the cell borders. In subconfluent monolayers, Gα12 and PKC ζ were found at the plasma membrane only along the areas of lateral cell-cell contact. These isoforms formed a pattern of distribution very similar to the ZO-1 protein. The present findings indicate that Gα12 and PKC ζ may be part of the zonula occludens complex and may locally regulate formation and permeability of tight junctions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002329900020
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  • 9
    Electronic Resource
    Electronic Resource
    A Collagen Substrate Enhances the Sealing Capacity of Tight Junctions of A6 Cell Monolayers (1997)
    Springer
    The journal of membrane biology 159 (1997), S. 263 -270 
    Details
    ISSN: 1432-1424
    Keywords: Key words: Tight junction — Intercellular junctions — Transepithelial permeability — Transepithelial electrical resistance (TER) — A6 epithelial cell cultures — Collagen.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract. A6 cells, a kidney derived epithelial cell line, when cultured either on a collagen-coated substrate or on polycarbonate substrate without collagen form confluent monolayers that are similar in cell density and overall morphology. However, the transepithelial electrical resistance (TER) of monolayers grown on the collagen-coated substrate is ninefold higher than that of monolayers grown without collagen. A comparative freeze-fracture study showed that this large difference in TER is not related to the length or number of tight junction strands but to differences in the specific conductance of individual strands. This conductance was obtained considering the TER, the linear junctional density and the mean number of tight junction strands. We estimated the specific linear conductance of the tight junction strands to be 2.56 × 10−7 S/cm for cells grown on collagen and 30.3 × 10−7 S/cm for the cells grown without collagen. We also examined changes in distribution and phosphorylation states of the zonula occludens associated protein, ZO-1, during monolayer formation. Immunocytochemistry reveals that the distribution of ZO-1 follows a similar time course and pattern independent of the presence or absence of collagen. While the amount of ZO-1 expression is identical in cells grown on both substrates, this protein is phosphorylated to a greater extent during the initial stages of confluence in cells cultured on collagen. We suggest that the phosphorylation levels of ZO-1 in A6 cells at the early stages of monolayer formation may determine the final molecular structure and specific conductance of the tight junctions strands.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002329900289
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  • 10
    Electronic Resource
    Electronic Resource
    Redistribution and Phosphorylation of Occludin During Opening and Resealing of Tight Junctions in Cultured Epithelial Cells (1999)
    Springer
    The journal of membrane biology 170 (1999), S. 147-156 
    Details
    ISSN: 1432-1424
    Keywords: Key words: Tight junction — Occludin — ZO-1 — Transepithelial resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract. We studied the expression, distribution, and phosphorylation of the tight junction (TJ) protein occludin in confluent MDCK cell monolayers following three procedures for opening and resealing of TJs. When Ca2+ is transiently removed from the culture medium, the TJs open and the cells separate from each other, but the occludin band around each cell is retained. When Ca2+ is reintroduced, the TJs reseal. When the monolayers are exposed to prolonged Ca2+ starvation the cells maintain contact, but occludin disappears from the cell borders and can be detected only in a cytoplasmic compartment. When Ca2+ is reintroduced, new TJs are assembled and the transepithelial electrical resistance (TER) is reestablished in about 20 hr. Monolayers treated with the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) show a different pattern of TJ opening: the cell-cell contact is maintained but the TJ strand network, as seen in freeze-fracture replicas, becomes discontinuous. Occludin is still localized at the cell periphery, but in a pattern of distribution that matches the discontinuous TJ. These TJs do not reseal even 24 hr after removal of the TPA. Western blot analysis showed that the 62–65 kD double band of occludin did not change with these treatments. However, in vivo phosphorylation analysis showed that the TPA treatment reduced the phosphorylation levels of occludin, while the prolonged Ca2+ starvation completely dephosphorylated the two occludin bands. In addition, a highly phosphorylated 71 kD band that immunoprecipitates with occludin is not present when TJ is opened by the Ca2+ removal. Phosphoaminoacid analysis showed that the 62–65 kD occludin bands are phosphorylated on serine and threonine, while the 71 kD band was phosphorylated exclusively on serine. Our results provide further evidence that phosphorylation of occludin is an important step in regulating TJ formation and permeability.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002329900544
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