Electron microscopic demonstration of an extracellular duplex lining layer of alveoli

Weibel, Ewald R.; Gil, Joan

doi:10.1016/0034-5687(68)90006-6

Cited by 226 publications

(77 citation statements)

References 20 publications

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“…However, the areas occupied by the tubes are similar, in TEM and AFM images, indicating that the internal areas of the tubes can be measured consistently using either technique, although resolution by each technique shows differences in the shapes of the structures. The dimensions of the tubes using AFM and TEM are in approximate agreement with each other and with those (published previously) in native and reconstituted TM by EM (Weibel and Gil, 1968;Williams, 1979;Suzuki et al, 1989).…”

Section: Resultssupporting

confidence: 88%

“…Surfactant is secreted by alveolar type II cells in the form of multiple bilayer structures called lamellar bodies (LB). LB undergo transformations in the alveolar fluid to form unusual closely packed arrays of square-shaped elongated nanotubes called tubular myelin (TM) (Weibel and Gil, 1968;Goerke and Clements, 1979;Hawgood, 1997). Surfactant lines the alveolar air-fluid interface with surfaceactive films, which prevent alveolar collapse at end expiration (Goerke and Clements, 1979;van Golde et al, 1994).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Correlated Atomic Force and Transmission Electron Microscopy of Nanotubular Structures in Pulmonary Surfactant

Nag

Munro

Hearn

et al. 1999

Journal of Structural Biology

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Pulmonary surfactant stabilizes the lung by reducing surface tension at the air-water interface of the alveoli. Surfactant is present in the lung in a number of morphological forms, including tubular myelin (TM). TM is composed of unusual 40 ؋ 40 nm square elongated proteolipid tubes. Atomic force microscopy (AFM) was performed on polymerembedded Lowicryl and London Resin-White (LRWhite) unstained thin sections. AFM was used in imaging regions of the sections where TM was detected by transmission electron microscopy (EM) of corresponding stained sections. Tapping-and contact-mode AFM imaging of the unstained sections containing TM indicated a highly heterogeneous surface topography with height variations ranging from 10 to 100 nm. In tapping-mode AFM, tubular myelin was seen as hemispherical protrusions of 30-70 nm in diameter, with vertical dimensions of 5-8 nm. In contact-mode AFM and with phase imaging using a sharper (G10 nm nominal radius) probe, square open-ended tubes which resembled typical electron micrographs of such regions were observed. The cross-hatch structures observed inside the tubes using EM were not observed using AFM, although certain multilobe structures and topographic heterogeneity were detected inside some tubes. Other regions of multilamellar bodies and some regions where such bilayer lamella appear to fuse with the tubes were found in association with TM using AFM. EM of acetone-delipidated tubes in LR-White revealed rectangular tubular cores containing cross-hatched structures, presumably protein skeletons. AFM surface topography of these regions showed hollow depressions at positions at which the protein was anticipated instead of the protrusions seen in the lipid-containing sections. Gold-labeled antibody to surfactant protein A was found associated somewhat randomly within the regions containing the protein skeletons. The topography of the gold particles was observed as sharp peaks in contact-mode AFM. This study suggests a method for unambiguous detection of threedimensional nanotubes present in low abundance in a biological macromolecular complex. Only limited detection of proteins and lipids in surfaces of embedded tubular myelin was possible. EM and AFM imaging of such unusual biological structures may suggest unique lipid-protein associations and arrangements in three dimensions. Academic Press

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Section: Resultssupporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Correlated Atomic Force and Transmission Electron Microscopy of Nanotubular Structures in Pulmonary Surfactant

Nag

Munro

Hearn

et al. 1999

Journal of Structural Biology

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“…At lowconcentration, double-bilayer vesicles are formed, whereas at higher concentrations they form multibilayer onion-like vesicles. The onion-like dendrimersomes provide simple and easily accessible mimics of various biological membranes of different cells and organelles such as Gram-negative bacteria (2, 3), cell nuclei (4), and multilamellar bodies (11,12). The direct and reverse injection method has been proven versatile and reliable with various solvents such as THF, acetone, acetonitrile, and 1,4-dioxane.…”

Section: Discussionmentioning

confidence: 99%

“…Gram-negative bacteria (2, 3) and the cell nucleus (4), however, exhibit a strikingly special envelope that consists of a concentric double-bilayer membrane. More complex membranes are also encountered in cells and their various organelles, such as multivesicular structures of eukaryotic cells (5) and endosomes (6), and multibilayer structures of endoplasmic reticulum (7,8), myelin (9, 10), and multilamellar bodies (11,12). This diversity of biological membranes inspired corresponding biological mimics.…”

mentioning

confidence: 99%

Self-assembly of amphiphilic Janus dendrimers into uniform onion-like dendrimersomes with predictable size and number of bilayers

Zhang

Sun

Hughes

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

147

160

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A constitutional isomeric library synthesized by a modular approach has been used to discover six amphiphilic Janus dendrimer primary structures, which self-assemble into uniform onion-like vesicles with predictable dimensions and number of internal bilayers. These vesicles, denoted onion-like dendrimersomes, are assembled by simple injection of a solution of Janus dendrimer in a water-miscible solvent into water or buffer. These dendrimersomes provide mimics of double-bilayer and multibilayer biological membranes with dimensions and number of bilayers predicted by the Janus compound concentration in water. The simple injection method of preparation is accessible without any special equipment, generating uniform vesicles, and thus provides a promising tool for fundamental studies as well as technological applications in nanomedicine and other fields.synthetic membranes | biomembrane mimics | multibilayer vesicles M ost living organisms contain single-bilayer membranes composed of lipids, glycolipids, cholesterol, transmembrane proteins, and glycoproteins (1). Gram-negative bacteria (2, 3) and the cell nucleus (4), however, exhibit a strikingly special envelope that consists of a concentric double-bilayer membrane. More complex membranes are also encountered in cells and their various organelles, such as multivesicular structures of eukaryotic cells (5) and endosomes (6), and multibilayer structures of endoplasmic reticulum (7,8), myelin (9, 10), and multilamellar bodies (11,12). This diversity of biological membranes inspired corresponding biological mimics. Liposomes ( Fig. 1) self-assembled from phospholipids are the first mimics of singlebilayer biological membranes (13-16), but they are polydisperse, unstable, and permeable (14). Stealth liposomes coassembled from phospholipids, cholesterol, and phospholipids conjugated with poly(ethylene glycol) exhibit improved stability, permeability, and mechanical properties (17)(18)(19)(20). Polymersomes (21-24) assembled from amphiphilic block copolymers exhibit better mechanical properties and permeability, but are not always biocompatible and are polydisperse. Dendrimersomes (25-28) self-assembled from amphiphilic Janus dendrimers and minidendrimers (26-28) have also been elaborated to mimic single-bilayer biological membranes. Amphiphilic Janus dendrimers take advantage of multivalency both in their hydrophobic and hydrophilic parts (23,(29)(30)(31)(32). Dendrimersomes are assembled by simple injection (33) of a solution of an amphiphilic Janus dendrimer (26) in a water-soluble solvent into water or buffer and produce uniform (34), impermeable, and stable vesicles with excellent mechanical properties. In addition, their size and properties can be predicted by their primary structure (27). Amphiphilic Janus glycodendrimers self-assemble into glycodendrimersomes that mimic the glycan ligands of biological membranes (35). They have been demonstrated to be bioactive toward biomedically relevant bacterial, plant, and human lectins, and could have numerous applications i...

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“…It can certainly be adsorbed to non-biological surfaces (Gershfield, 1979;Hills, 1982Hills, , 1983 and to cutaneous and tracheal epithelium Hills, 1982). In the lung, osmium densities (long used as a markerfor surfactant (Goldenburg, Buckingham & Sommers, 1969) can be seen on as much of the epithelial surface as demonstrated at the air-aqueous interface in electron micrographs used by Gil & Weibel (1969) and Weibel & Gil (1968) to determine the location of surfactant. Direct adsorption to the tissue itself could be much more extensive than demonstrated since, as Untersee, Gil & Weibel (1971) point out, any fixation process destroys hydrophobic layers.…”

Section: Introductionmentioning

confidence: 99%

'De‐watering' capabilities of surfactants in human amniotic fluid.

Hills¹

1984

The Journal of Physiology

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The phospholipid extracts from each of eleven samples of human amniotic fluid obtained from eleven full‐term births were deposited as orientated monolayers adsorbed to glass. The surfaces were found to be rendered hydrophobic with maximum contact angles averaging 54.5 degrees while, upon withdrawing fluid, the edge of the saline pool receded to expose dry surface with minimum contact angles averaging 15.4 degrees. The extracts were found to be surface‐active at the liquid‐air interface and there was some indication that direct adsorption to solid surfaces was facilitated by calcium ions. It was found that, in all extracts, a continuous layer of saline adjacent to the adsorbed surface would break up spontaneously to expose dry surface when the thickness was reduced to an average of 764 micron, corresponding to several alveolar diameters. This phenomenon is discussed as a possible means of establishing dry patches on the alveolar membrane, especially in the new‐born after the fetal alveolar wall has been exposed to the same surfactants in much the same physical form as found in amniotic fluid. Surfactant adsorbed directly to the tissue subphase is suggested as a physical basis for the discontinuity of the aqueous hypophase seen in many electron micrographs of the adult alveolus. This 'de‐watering' of the alveolar surface could facilitate gas transfer.

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Electron microscopic demonstration of an extracellular duplex lining layer of alveoli

Cited by 226 publications

References 20 publications

Correlated Atomic Force and Transmission Electron Microscopy of Nanotubular Structures in Pulmonary Surfactant

Correlated Atomic Force and Transmission Electron Microscopy of Nanotubular Structures in Pulmonary Surfactant

Self-assembly of amphiphilic Janus dendrimers into uniform onion-like dendrimersomes with predictable size and number of bilayers

'De‐watering' capabilities of surfactants in human amniotic fluid.

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