Sterol‐polyene antibiotic complexation: Probe of membrane structure

Bittman, Robert

doi:10.1007/bf02533746

Cited by 70 publications

(24 citation statements)

References 59 publications

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“…The polyene filipin (23,24,25), which I will use to demonstrate this disparity in sterol content, is helpful in a couple of ways . K. Hong and D. P. Papahadjopoulos (both of the University of California) and I have used it to determine filipin's sensitivity to the membrane-sidedness of sterols after introducing cholesterol into the lipid bilayer of phosphatidylcholine liposomes.…”

Section: Resultsmentioning

confidence: 99%

Plasma-membrane diversity in a highly polarized cell.

Friend¹

1982

The Journal of Cell Biology

181

100

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In their classical experiments on membrane fluidity, Frye and Edidin (1) triggered further research on the fluid mosaic model of membrane structure (2) in numerous other laboratories . Since then, investigators in this field have also emphasized the planar, functionally specialized mosaics within the generally fluid bilayer of the membrane. These mosaics comprise areas where specific groups of lipids, proteins, glycoconjugates, and sterols aggregate to mediate specific functions . To cite several different facets of the membrane-domain concept, we can recall the now familiar work of Goldstein et al. (3) on the distinctive participation of coated pits in receptor-mediated endocytosis. Other thought-provoking membrane regionalities are the rosette-particle arrays instrumental in mucocyst secretion in Tetrahymena (4), the need for specific lipids for the complete activity of cytochrome c oxidase and other membrane-related enzymes (5), and the variations of phospholipid content in continuous membrane systems . (Consider the nuclear envelope and the rough-surfaced endoplasmic reticulumThe Symposium on Plasma-Membrane Diversity (see footnote) involved the existence and topography of such polysaccharide, lipid, and protein mosaics in the plasma membrane . We addressed ourselves to the broad questions : Do our methods and techniques verify the presence of domains in living cells? Where these membrane domains apparently exist, are their structure and composition pertinent to specific membrane-functions? How are domains sustained in a supposedly fluid environment? And when they reside in the depth as well as the plane of the bilayer, can we manipulate them to modify plasma-membrane and cell function?Plasma-membrane Diversity in a Highly Polarized CellSince motile sperm were first observed by Leowenhok via light microscopy more than 300 years ago, we have been aware that the spermatozoon is a highly polarized cell . Austin (7) and Bedford and Cooper (8), among others, authoritatively demonstrated that the various regions of this cell served different This work was presented in a Symposium

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Section: Resultsmentioning

confidence: 99%

Plasma-membrane diversity in a highly polarized cell.

Friend¹

1982

The Journal of Cell Biology

181

100

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“…That this more tightly bound portion of gp7O was not liberated is taken as evidence that nystatin does not perturb the envelope strongly enough to be disruptive. Channel formation by nystatin requires the presence of cholesterol in the membrane (21,22) There is ample evidence that viruses budding from the cell membrane take lipids from the host cell, and, in the case of retroviruses, the concentration of cholesterol in the viral membrane appears to be enriched compared to the host membrane (23).…”

Section: Discussionmentioning

confidence: 99%

Disassembly of viral membranes by complement independent of channel formation.

Esser¹,

Bartholomew²,

Jensen³

et al. 1979

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

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We have compared the effects of the complement membrane attack complex (MAC), nystatin, and melittin on the envelope of murine leukemia viruses to determine if channel formation alone is sufficient to cause membranolysis. Nystatin is a channel former and mellitin is not, although both are hemolytic. Whereas MAC and melittin disintegrated the viral membrane, nystatin had no effect on mo hology, integ- (2), who measured the release of radiolabeled RNA from mouse leukemia viruses (retroviruses). Later experiments with retroviruses indicated that human complement alone, without specific antibody, could lyse retroviruses (3-5). The mechanism of lysis of enveloped viruses was assumed to be similar or identical to complement-mediated lysis of mammalian cells, a more extensively studied and better understood reaction.In complement-dependent cytolysis, five complement proteins-C5b, C6, C7, C8, and C9-become physically attached to the outer membrane of a cell. Without further enzymatic modification, these proteins form a multimolecular complex, the membrane attack complex (MAC), that lyses cells by purely physicochemical means (reviewed in ref. 6). Loss of the natural impermeability of the cell membrane to small solutes leads to colloid-osmotic swelling of the cell, rupture, and release of internal proteins. Mayer (7,8) theorized that the MAC forms hydrophilic protein channels; this action is reminiscent of the channel-forming (9) and hemolytic (10) properties of the antibiotics nystatin and amphotericin B.In contrast to Mayer's channel theory, we recently proposed (11, 12) that the MAC is membranolytic not because of channel formation, but because of its strong phospholipid binding capacity, through which it is enabled to reorient the lipid bilayer structure of membranes.Examining our hypothesis, we have compared the effects of nystatin, melittin, and the MAC on the envelope of murine leukemia virus (MuLV) to determine if channel formation alone is sufficient to cause membranolysis. Nystatin is a channel former and melittin is not, although it is membranolytic. Our results show that whereas the MAC and melittin are virolytic, nystatin has no effect on the morphology and infectivity of the virus.MATERIALS AND METHODS Materials. Nystatin, amphotericin B, and melittin were purchased from Sigma. Rauscher MuLV, prepared by Electro-Nucleonics (Bethesda, MD), was supplied by the Office of Program Resources and Logistics, Viral Oncology, National Cancer Institute. Freshly harvested Moloney, xenotropic (ATS-124) murine, and (BN-p 454-9) rat leukemia viruses were propagated as described (6). Fresh human serum (Community Blood and Plasma, San Diego, CA) frozen at -70'C was used as a source of complement.Uranyl formate was prepared according to published procedures (13); all other chemicals were of the best grade commercially available. Buffer osmolarities were measured with a freezing-point depression osmometer (Osmette, Precision Systems, Sudbury, MA).Virolysis Assays. Virus samples (100,ug or approximately 1010 virions ...

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“…We used sterol-specific filipin staining, which shows fluorescence upon forming a complex with 3-hydroxysterols, 12) to detect sterol accumulation in C. elegans. [16][17][18]25) As shown Fig. 5, worms grown in ginsenoside Rb 1 or Rc supplement were bigger than those grown in cholesterol-deprived medium and exhibited stronger fluorescence in whole body with discrete internal organs than those grown in cholesteroldeprived medium, although ginsenoside Rb 1 and Rc have no 3-hydroxy group at carbon-3 instead have two carbohydrates (Fig.…”

Section: Discussionmentioning

confidence: 73%

“…Filipin is a fluorescent polyene antibiotic that forms tight and specific complexes with 3b-hydroxy sterols. [15][16][17][18] As shown in Fig. 5, we could observe that worms grown in ginsenoside Rb 1 or Rc (300 mM)ϩcholesterol-deprived medium were much bigger than those grown in cholesterol-deprived medium and that exhibited strong filipin staining of whole body of worms with discrete internal organs compared with those grown in cholesterol-deprived medium.…”

Section: Effects Of Ginsenoside Rb 1 and Rc On Filipin Staining Of Cmentioning

confidence: 74%

Effects of Ginsenosides, Active Ingredients of Panax ginseng, on Development, Growth, and Life Span of Caenorhabditis elegans

Lee

Choi²,

Kwon

et al. 2007

Biological & Pharmaceutical Bulletin

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Ginseng, the root of Panax ginseng C. A. MEYER, has been used as a representative tonic for two thousand years in the Far East countries like Korea, China, and Japan. Now, ginseng is one of the most famous and precious herbal medicines consumed around the world. 1) Although ginseng exhibits multiple pharmacological actions in vitro or in vivo studies, its mechanisms on various efficacies are still elusive. Recent accumulating evidences show that ginseng saponins (or ginsenosides) are the main active ingredients of ginseng (Fig. 1). Ginseng root contains 3-4% of ginseng saponins. Ginseng saponins are especially abundant in fine roots rather than main body of ginseng root. Ginseng saponins are one of glycoside saponins and one of the derivatives of triterpenoid dammarane consisting of thirty carbon atoms. Each ginsenoside has a common hydrophobic four ring cholesterol-like backbone structure with sugar moieties attached. About 30 different types of ginseng saponins have been isolated and identified from the root of Panax ginseng (Fig. 1).Caenorhabditis elegans (C. elegans) is one of nematode species and is one of free living animals under the earth rather than is parasitic in host animals or plants. C. elegans takes its food from dead animals or plants. Since C. elegans has short life cycle and large amounts of worms can be easily grown for biochemical assays or genetic studies in the laboratory, the organism is one of the well-established genetic models and its development processes have well characterized. Interestingly, C. elegans cannot synthesize sterols unlike other The backbone structure of ginsenosides, active ingredients of Panax ginseng, is similar with that of sterol, especially cholesterol. Caenorhabditis elegans (C. elegans) is one of free living nematodes and is well-established animal model for biochemical and genetic studies. C. elegans cannot synthesize de novo cholesterol, although cholesterol is essential requirement for its growth and development. In the present study, we investigated the effects of ginseng total saponins (GTS) on the average brood size, growth, development, worm size, and life span of C. elegans in cholesterol-deprived and -fed medium. Cholesterol deprivation caused damages on normal growth, reproduction, and life span of worms throughout F1 to F3 generations. GTS supplement to cholesterol-deprived medium restored the growth, reproduction, and life span of worms as much as cholesterol alone-fed medium. GTS co-supplement to cholesterol-fed medium not only promoted worm reproduction but also induced bigger worms and faster growth than cholesterol-fed medium. In study to identify which ginsenosides are responsible for life span restoring effects of GTS, we found that ginsenoside Rc supplement not only restored life span of worms grown in cholesterol-deprived medium but also prolonged life span of worms grown in cholesterol-fed medium. Worms grown in medium supplemented with ginsenoside Rb 1 or Rc to cholesterol-deprived medium exhibited strong filipin staining, in which filipin f...

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Sterol‐polyene antibiotic complexation: Probe of membrane structure

Cited by 70 publications

References 59 publications

Plasma-membrane diversity in a highly polarized cell.

Plasma-membrane diversity in a highly polarized cell.

Disassembly of viral membranes by complement independent of channel formation.

Effects of Ginsenosides, Active Ingredients of Panax ginseng, on Development, Growth, and Life Span of Caenorhabditis elegans

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