Stanley Bullivant

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The cells in the mammalian lens are electrically and metabolically coupled with each other by a network of gap junctions. These are clusters of transmembrane channels by which the fibre cells situated deeper in the lens communicate through the epithelium with the aqueous humour, the source of nutrients for the lens. Hence gap junctions are important for(More)
Thin section electron microscopy reveals two different types of membrane interactions between the fiber cells of bovine lens. Monoclonal antibodies against lens membrane protein MP70 (Kistler et al., 1985, J. Cell Biol., 101:28-35) bound exclusively to the 16-17-nm intercellular junctions. MP70 localization was most dramatic in the lens outer cortex and(More)
A 70,000-D membrane protein (MP70), which is restricted to the eye lens fibers and is present in immunologically homologous form in many vertebrate species, has been identified. By use of anti-MP70 monoclonal antibodies for immunofluorescence microscopy and electron microscopy, this polypeptide was localized in lens membrane junctional domains. Both(More)
The tight junction, or zonula occludens (ZO), forms a semi-permeable barrier in the paracellular pathway in most vertebrate epithelia. The ZO is the apical-most member of a series of intercellular junctions, collectively known as the junctional complex, found at the interface of the apical and lateral cell surface. This structure not only restricts movement(More)
Symbionts first reported from the gut of a Red Sea surgeonfish, Acanthurus nigrofuscus (family Acanthuridae), were subsequently described as Epulopiscium fishelsoni. The taxonomic position of this very large (up to 576 microns in length) microorganism has previously been designated in the literature as either uncertain or eukaryotic. We suggest that similar(More)
A modification of the freeze-fracturing technique to permit observation of replicas of both sides of the fracture is described. It has been used to study mouse liver cell membrane structure. Membranes break to give two faces with three-dimensional complementarity, although there is some small-scale mismatching which is discussed. Since the two distinctive(More)
Cells of Chironomus salivary glands and Malpighian tubules have junctions of the "septate" kind. This is the only kind of junction discerned which is large enough to effect the existing degree of intercellular communication. The electron microscopic observations of the "septate" junction conform to a honeycomb structure, with 80-A-thick electron-opaque(More)
A wide variety of plant and animal tissues were prepared for electron microscopy by freeze-substitution, after rapid freezing on a liquid nitrogen cooled copper block by the van Harreveld method. Measurements were made of ice crystal size versus depth in tissues that had not been treated with any cryoprotectants. Ice crystal size increased exponentially(More)
Membrane protein MP70 is a component specifically of lens fiber 16-17 nm junctions. SDS-PAGE analysis of membrane preparations made separately from the sheep lens equatorial region (outer cortex), inner cortex and central region (nucleus) showed abundant MP70 in the young fibers in the outer cortex and drastically reduced levels of MP70 in the older fibers(More)