The structure of a model pulmonary surfactant as revealed by scanning force microscopy

Nahmen, A. von; Schenk, Michael; Sieber, Manfred; Amrein, M.

doi:10.1016/s0006-3495(97)78687-9

Cited by 163 publications

(190 citation statements)

References 34 publications

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“…In the latter, conspicuous web-like phases are formed, but the phase separation typical for pure phospholipid films is absent. This latter observation is in good agreement with findings obtained by fluorescence microscopy [11,13,14] and also by SFM [14,15] on phospholipid films which have been enriched with SP-C. It could be argued that the difference is due to the different processing of the surfactant material, and it is conceivable that the proteins are more homogeneously distributed in Curosurf1 than in material first concentrated and then diluted.…”

Section: Discussionsupporting

confidence: 90%

“…SFM offers the advantage that neither fixation nor staining is required for imaging organic films, such that potential artefacts can be eliminated. With regard to lung surfactant films, the group of AMREIN and coworkers [14,15] has produced quite recently the first and most revealing micrographs of particular films of different compositions. In the present study, similar techniques have been applied in order to address the following questions: 1) what are the structural differences between films from pure phospholipids and those containing phospholipids and the surfactant proteins (SP)-B and SP-C?…”

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confidence: 99%

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Structures of surfactant films: a scanning force microscopy study

Grunder¹,

Gehr²,

Bachofen³

et al. 1999

Eur Respir J

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The alveolar lining layer is thought to consist of a continuous duplex layer, i.e., an aqueous hypophase covered by a thin surfactant film which is a monolayer with dipalmitoyl-phosphatidylcholine (DPPC) as its most important component. Findings obtained by electron microscopy and results from in vitro experiments suggest, however, that the structure and hence the structure-function relations of surfactant films are more complex. In order to better define their structures films of surfactants were studied by scanning force microscopy.Four different surfactants were spread on a Langmuir-Wilhelmy balance, and then transferred onto a solid mica plate by the Langmuir-Blodgett technique, under various states of film compression. Imaging of the films by scanning force microscopy was performed in the contact (repulsive) mode in air.The scanning force micrographs revealed that surfactant films are not homogeneous, but rather undergo phase transitions depending on the surface pressures. Even at comparable surface pressures different surfactants show quite different surface patterns. Differences in surface structure can even be observed in films containing surfactant proteins (SP)-B and SP-C.These observations give further evidence that the widely accepted hypothesis of a regular monolayer of phospholipids governing the surface tension probably does not hold true, but that the structure-function relationship of surface active surfactant films is even more complex than hitherto thought. Eur Respir J 1999; 14: 1290±1296. According to a widely accepted hypothesis the alveolar lining layer has the following structural properties: it is a continuous duplex layer consisting of an aqueous hypophase covered by a thin surfactant film, and the surfactant film is a monolayer with dipalmitoyl-phosphatidylcholine (DPPC) as its most important component [1±4].There are numerous studies of the structure of the lining layer, all of which are fragmentary. Indeed, the sample preparation and preservation of this delicate structure for microscopy is extremely difficult; there is no standard to distinguish between facts and artefacts [5], and it is not easy to conceive of how monolayers of saturated phospholipids can be preserved and visualized by the usual fixatives [6]. As to the first condition, i.e., the existence and continuity of a duplex layer, GIL and WEIBEL [7] were the first to convincingly demonstrate a two-phase lining layer by transmission electron microscopy. However, the film was often fragmented and disposed in patches, and could not be detected on flat parts of the alveolar walls. Although studies of freeze-fractured preparations suggested its continuity [8], the exact structure of the lining layer has remained a matter of debate. More recently, BAS-TACKY et al. [9] have clearly demonstrated the continuity of the lining layer by low-temperature electron microscopy, and improved tissue preparations have also resulted in a better visualization of the film such that all of the evidence now available suggests a continuum...

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Section: Discussionsupporting

confidence: 90%

mentioning

confidence: 99%

Structures of surfactant films: a scanning force microscopy study

Grunder¹,

Gehr²,

Bachofen³

et al. 1999

Eur Respir J

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“…Figure 2 shows the π -A and DV-A isotherms for mixtures with X Hel 13-5 ≤ 0. This phenomenon has been well-discussed elsewhere 36,37 .…”

Section: Fluorescence Microscopy Fmsupporting

confidence: 59%

Interfacial Behavior of Pulmonary Surfactant Preparations Containing Egg Yolk Lecithin

Nakahara

Shibata

2014

J. Oleo Sci.

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“…by compounds found in M. flabellifolia ; Bangham et al, 1979 ;Crowe et al, 1984a,b ;Drennan et al, 1993 ;Crowe & Crowe, 2000). Furthermore, there are striking similarities in morphology and function between the xylem lining and the surfactant film lining the pulmonary air spaces of mammals, which contains 80% DPPC (Morley et al, 1978 ;Bangham et al, 1979 ;Shelley et al, 1982 ;Oosterlaken-Dijksterhuis et al, 1991 ;Schu$ rch et al, 1994Schu$ rch et al, , 1995von Nahmen et al, 1997). The main function of the surfactant system is reduction of surface tension at the alveolar air-liquid interface at the end of expiration to minimize the capillary pressure created by decreased alveolar radius (Johansson et al, 1994).…”

Section: What Is the Chemical Composition Of The Lipid Layer ?mentioning

confidence: 99%

Xylem conduits of a resurrection plant contain a unique lipid lining and refill following a distinct pattern after desiccation

Schneider

Mimietz

et al. 2000

New Phytologist

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The axial and radial refilling with water of cut dry branches (up to 80 cm tall) of the resurrection plant Myrothamnus flabellifolia was studied in both acro-and basipetal directions by using "H-NMR imaging. NMR measurements showed that the conducting elements were not filled simultaneously. Axial water ascent occurred initially only in a cluster of a very few conducting elements. Refilling of the other conducting elements and of the living cells was mainly achieved by radial extraction of water from these initial conducting elements. With time, xylem elements in a few further regions were apparently refilled axially. Radial water spread through the tissue occurred almost linearly with time, but much faster in the acropetal than in the basipetal direction. Application of hydrostatic pressure (up to 16 kPa) produced similar temporal and spatial radial refilling patterns, except that more conducting elements were refilled axially during the first phase of water rise. The addition of raffinose to the water considerably reduced axial and radial spreading rates. The polarity of water climbing was supported by measurements of the water rise in dry branches using the ' light refraction ' (and, sometimes, the ' leaf recurving') method. Basipetal refilling of the xylem conduit exhibited biphasic kinetics ; the final rise height did not exceed 20-30 cm. Three-cm-long branch pieces also showed a directionality of water climbing, ruling out the possibility that changes in the conducting area from the base to the apex of the branches were responsible for this effect. The polarity of water ascent was independent of gravity and also did not change when the ambient temperature was raised to c. 40mC. At external pressures of 50-100 kPa the polarity disappeared, with basipetal and acropetal refill times of the xylem conduit of tall branches becoming comparable. Refilling of branches dried horizontally (with a clinostat) or inverted (in the direction of gravity) showed a pronounced reduction of the acropetal water rise to or below basipetal water climbing level (which was unaffected by this treatment). Unlike water, benzene and acetone climbing showed no polarity. In the case of benzene, the rise kinetics (including the final heights) were comparable with those measured acropetally for water, whereas with acetone the rise height was less. Transmission electron microscopy of dry branches demonstrated that the inner surfaces of the conducting tracheids and vessels were lined with a continuous osmiophilic (lipid) layer, as postulated by the kinetic analysis and light microscopy studies. The thickness of the layer varied between 20 and 80 nm. The parenchymal and intervessel pits as well as numerous tracheid corners contained opaque inclusions, presumably also consisting of lipids. Electron microscopy of rehydrated plants showed that the lipid layer was either thinned or had disintegrated and that numerous vesicle-like structures and lipid bodies were formed (together with various intermediate structural elements). These, many other da...

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The structure of a model pulmonary surfactant as revealed by scanning force microscopy

Cited by 163 publications

References 34 publications

Structures of surfactant films: a scanning force microscopy study

Structures of surfactant films: a scanning force microscopy study

Interfacial Behavior of Pulmonary Surfactant Preparations Containing Egg Yolk Lecithin

Xylem conduits of a resurrection plant contain a unique lipid lining and refill following a distinct pattern after desiccation

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