The correlation between the saturation of membrane fatty acids and the presence of membrane fracture faces after osmium fixation

James, R.; Branton, Daniel

doi:10.1016/0005-2736(71)90150-7

Cited by 41 publications

(15 citation statements)

References 32 publications

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“…5 A); it is possible, though, that these structures contained small perforations in the membranes, especially at the early stages of their formation, that are not visible in cryo-EM images. Specimens osmicated prior to freezing to allow fractures across lipid bilayers (28,44) revealed contents within the spherical structures that were consistent with the cytoplasmic material observed by TEM of the later doublemembrane-bound vesicles ( Fig. 5B and C).…”

Section: Multistage Remodeling Of Cellular Membranes In Poliovirusinfsupporting

confidence: 75%

Complex Dynamic Development of Poliovirus Membranous Replication Complexes

Belov

Nair

Hansen

et al. 2012

J Virol

208

296

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Replication of all positive-strand RNA viruses is intimately associated with membranes. Here we utilize electron tomography and other methods to investigate the remodeling of membranes in poliovirus-infected cells. We found that the viral replication structures previously described as "vesicles" are in fact convoluted, branching chambers with complex and dynamic morphology. They are likely to originate from cis-Golgi membranes and are represented during the early stages of infection by singlewalled connecting and branching tubular compartments. These early viral organelles gradually transform into doublemembrane structures by extension of membranous walls and/or collapsing of the luminal cavity of the single-membrane structures. As the double-membrane regions develop, they enclose cytoplasmic material. At this stage, a continuous membranous structure may have double-and single-walled membrane morphology at adjacent cross-sections. In the late stages of the replication cycle, the structures are represented mostly by double-membrane vesicles. Viral replication proteins, doublestranded RNA species, and actively replicating RNA are associated with both double-and single-membrane structures. However, the exponential phase of viral RNA synthesis occurs when single-membrane formations are predominant in the cell. It has been shown previously that replication complexes of some other positive-strand RNA viruses form on membrane invaginations, which result from negative membrane curvature. Our data show that the remodeling of cellular membranes in poliovirusinfected cells produces structures with positive curvature of membranes. Thus, it is likely that there is a fundamental divergence in the requirements for the supporting cellular membrane-shaping machinery among different groups of positive-strand RNA viruses.

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Section: Multistage Remodeling Of Cellular Membranes In Poliovirusinfsupporting

confidence: 75%

Complex Dynamic Development of Poliovirus Membranous Replication Complexes

Belov

Nair

Hansen

et al. 2012

J Virol

208

296

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show abstract

“…During dehydration, the lipid is extracted with organic solvents resulting in a collapse of adipocytes. Moreover, chemical fixatives are believed to alter the fine structure of lipid (15). In the freeze-fracture technique it is not necessary to use chemical fixatives, and so the fine structure of lipid droplets can be seen.…”

Section: Discussionmentioning

confidence: 99%

Morphological studies on adipocytes from obese rats - scanning and freeze-fracturing electron microscopy.

Mizunuma

Takahashi

Kawaguchi

et al. 1981

Acta Histochem. Cytochem

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“…Another indication of differences in protein organization between the reconstituted and native membranes comes from freeze-fracturing electron microscopy. Both the convex and concave fracture faces of reconstituted A. laidlawii membranes were fairly smooth, like those of myelin (46) or liposomes (47), lacking the characteristic particles seen in native membranes. The results were the same in the case of reconstituted membranes formed from SDS-solubilized material (26) and in the case of those from membrane material solubilized by bile salts (Fig.…”

Section: The Molecular Organization Of the Reconstituted Membranesmentioning

confidence: 95%

Reconstitution of mycoplasma membranes

Razin

1974

J Supramol Struct

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Detergent-solubilized proteins and lipids of mycoplasma membranes reassemble spontaneously into membranous structures on t h e removal or dilution of the detergent in the presence of divalent cations. The cations seem t o function by neutralizing the negatively charged groups on membrane lipids and proteins which interfere by electrostatic repulsion with membrane reassembly. Moreover, salt bridges formed by the divalent cation between acidic groups on membrane proteins and lipids seem t o play an important role in the reconstituted membrane stability. Electron transport activity, as measured by the transport of electrons from NADH t o oxygen, has been demonstrated in reconstituted Acholeplasma laidlawii membranes. However, restoration of active transport of sugars or ions has not been achieved so far. The conditions for obtaining properly sealed vesicles, which are obligatory for demonstrating transport activity, are still rather poorly defined. The reassembled membranous structures cannot be distinguished from the native membranes in chemical composition, density, and thin sections. However, probe techniques, x-ray diffraction, and freeze-fracturing electron microscopy indicate that the proteins are organized differently in the reassembled membranes, though the lipid bilayer is restored. The results obtained so far leave little hope for successfully reconstituting the molecular organization of membranes as complex as those of mycoplasmas by a single-step reassembly of detergent-solubilized membrane components. The prospects appear brighter with membranes having only a few protein species, such as the outer membrane of gram-negative bacteria. In spite of the failure t o reconstitute fully active mycoplama membranes, the reassembly procedure was found valuable in studying the interactions of detergent-solubilized membrane proteins with lipids, the effects of a hydrophobic environment on hydrophilic enzymes, and the production of ''hybrid" membranes having selected membrane components.

show abstract

The correlation between the saturation of membrane fatty acids and the presence of membrane fracture faces after osmium fixation

Cited by 41 publications

References 32 publications

Complex Dynamic Development of Poliovirus Membranous Replication Complexes

Complex Dynamic Development of Poliovirus Membranous Replication Complexes

Morphological studies on adipocytes from obese rats - scanning and freeze-fracturing electron microscopy.

Reconstitution of mycoplasma membranes

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