Formation of high-axial-ratio-microstructures from natural and synthetic sphingolipids

Goldstein, Alex S.; Lukyanov, Anatoly N.; Carlson, Paul A.; Yager, Paul; Gelb, Michael H.

doi:10.1016/s0009-3084(97)00042-x

Cited by 31 publications

(45 citation statements)

References 33 publications

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“…They are too large to be cylindrical micelles since galactocerebrosides are known to have a bilayer thickness of 5.5-6.5 nm (Marsh, 1990) and the structures have no visible seam to indicate a cochleate (spiraled bilayer) structure. There have been electron microscopy reports of nanotube formation by various galactocerebrosides in bulk solution with sizes that varied between 25 and 150 nm in diameter and up to 10 m in length (Archibald and Mann, 1994;Goldstein et al, 1997;Kulkarni et al, 1999). Our dimensions obtained with AFM are within this range.…”

Section: Discussionsupporting

confidence: 59%

“…Our dimensions obtained with AFM are within this range. Depending on the method of preparation, a number of structures besides nanotubes have also been observed (Archibald and Mann, 1994;Goldstein et al, 1997;Kulkarni et al, 1999) for which a general theory of formation has been derived (Selinger et al, 1996). However, no micrometer scale organization of these various nanostructures has been reported.…”

Section: Discussionmentioning

confidence: 99%

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Atomic Force Microscopy of Nonhydroxy Galactocerebroside Nanotubes and Their Self-Assembly at the Air–Water Interface, with Applications to Myelin

Ohler

Revenko

Husted

2001

Journal of Structural Biology

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Myelin is one of the few biological membranes to contain the lipid galactocerebrosides, although their role in myelin is unclear. To explore its structural role, we used fluorescence and atomic force microscopy (AFM) to study nonhydroxy galactocerebrosides (NCer) at the air-water interface of a Langmuir-Blodgett trough. Fluorescence microscopy at the air-water interface indicated that NCer forms micrometer scale domains of varying radii with six fractal-like extensions. Atomic force microscopy using TappingMode in water on samples transferred to mica confirmed the fractal-like domain structure in the absence of dye and showed that the domains consisted of many aggregated nanotubes with a diameter of 30 nm. The Hausdorf fractal dimension was estimated to be 1.26 and 1.11 for two domains imaged with AFM. This evidence indicates that NCer forms a bulk phase of nanotubes at the air-water interface, unlike the liquidcondensed phase of a phospholipid monolayer. That NCer forms bilayer nanotubes that aggregate strongly suggests NCer helps maintain the stability of myelin by contributing to the curvature and adhesion of the membrane. We found that NCer appears to be decreased in myelin from multiple sclerosis normal appearing white matter, which could be an important event in the loss of myelin stability.

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Section: Discussionsupporting

confidence: 59%

Section: Discussionmentioning

confidence: 99%

Atomic Force Microscopy of Nonhydroxy Galactocerebroside Nanotubes and Their Self-Assembly at the Air–Water Interface, with Applications to Myelin

Ohler

Revenko

Husted

2001

Journal of Structural Biology

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“…66,67 Manipulations of the acyl chain or head group were found to play a significant role in modulating cylindrical microstructure formation. The saturated version of the 24-carbon acyl chain (N -24 : 0) nonhydroxy GalCer (20) formed undulating ribbons in water that occasionally showed a twisted region.…”

Section: Cerebrosidesmentioning

confidence: 99%

“…Similar morphologies were also found for the same glycolipid in water-DMF solutions. 66 Shortening the chain length to 20 carbons, with one double bond (20 : 1 11 ), resulted in the formation of righthanded helical ribbons. 65 The bulkier zwitterionic phosphocholine head group was found to inhibit the formation of tubules.…”

Section: Cerebrosidesmentioning

confidence: 99%

“…65 This work also leads to the conclusion that stabilization of helical ribbons or edges sealing to form tubes are dependent upon experimental conditions as described by the model of Schnur et al 68 Head group structural modifications have been observed to influence the morphology of glycolipid assemblies. 66,67 Replacement of the galactose head group with N -acetyl-glycine yielded long, thin fibers, whereas the N -acetylproline analogue gave amorphous assemblies. 66 Glucose leads to needlelike and fiberlike microstructures.…”

Section: Cerebrosidesmentioning

confidence: 99%

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