Membrane fusion: studies with a calcium-sensitive dye, arsenazo III, in liposomes.

Dunham, Philip B.; Babiarz, Paula; Israel, Alan; Zerial, Aurelio; Weissmann, Gerald

doi:10.1073/pnas.74.4.1580

Cited by 23 publications

(11 citation statements)

References 28 publications

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“…It was suggested that these drugs stabilize mem branes, thus inhibiting the fusion between membrane surfaces, upon which both phagocytosis and degranula tion depend [14]. At present, however, we cannot decide to which extend differences in lactoferrin levels can be attributed solely to immunosuppressive therapy.…”

Section: Discussionmentioning

confidence: 83%

Plasma Levels of Main Granulocyte Components during Hemodialysis: Effects of Immunosuppression

Riegel¹,

Leverenz²,

Schollmeyer³

et al. 1987

Nephron

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Plasma levels of granulocyte lactoferrin, granulocyte myeloperoxidase and granulocyte elastase in complex with α_rproteinase inhibitor were investigated during hemodialysis in oliguric patients following cadaveric renal transplantation (CRT). The results were compared with those of patients undergoing regular hemodialysis treatment (RDT) using different membrane materials. In RDT patients, plasma lactoferrin levels increased from 61.9 ± 10.2 to 417.9 ± 96.7 using dialyzers made of cuprophane. Dialyzers made of polymethyl methacrylate induced an increase of lactoferrin from 166.6 ± 28.5 to 712.5 ± 165.9 and dialyzers made of polyacrylonitrile an increase from 122.6 ± 23.5 to 647.7 ± 203.6 ng/ml. In CRT patients, in contrast, plasma lactoferrin levels increased from 49.1 ± 10.9 to 199.6 ± 45.9 (cuprophane), from 30.1 ± 6.9 to 252.5 ± 46.9 (polymethyl methacrylate), and from 43.3 ± 9.1 to 174.2 ± 39.3 ng/ml (polyacrylonitrile). On the other hand, the plasma levels’ of myeloperoxidase and elastase in complex with αi-proteinase inhibitor increased comparably in both groups of patients. Our data suggest that immunosuppression might prevent degranulation of specific granules independently of the used dialyzer membrane material, whereas no effect was observed on two main components of azurophilic granules.

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Section: Discussionmentioning

confidence: 83%

Plasma Levels of Main Granulocyte Components during Hemodialysis: Effects of Immunosuppression

Riegel¹,

Leverenz²,

Schollmeyer³

et al. 1987

Nephron

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“…Part of this disagreement may represent real differences in the vesicle systems used including contamination by trace amounts of fusogens or antifusogens (Dunham et al, 1977;Kantor & Prestegard, 1978;Larrabee, 1979). However, the problem is traditionally complicated by the difficulty of distinguishing "true" fusion of topologically distinct bilayers to produce a single bilayer from aggregation of vesicles that otherwise remain intact.…”

Section: Discussionmentioning

confidence: 96%

Fusion of dipalmitoylphosphatidylcholine vesicles

Schullery¹,

Schmidt²,

Felgner³

et al. 1980

Biochemistry

183

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Small unilamellar dipalmitoylphosphatidylcholine vesicles formed by sonication are shown to fuse spontaneously below the phase transition temperature. The ultimate fusion products are unilamellar vesicles about 700 A in diameter, which are stable and provide an intact ionic permeation barrier either above or below the phase transition. The fused vesicles have been characterized by gel chromatography, trapped volume, 31P nuclear magnetic resonance, and negative stain and freeze-fracture electron microscopy.

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“…However, direct proof of vesicle fusion requires mixing of intravesicular contents. Such proof has been provided by a study in which the calcium-sensitive dye, arzenazo III was mixed with EDTA through vesicle fusion to cause a spectral light shift (Dunham et al, 1977). More recently, Ingolia and Koshland (1978) have reported a vesicular fusion assay which utilizes the reaction of firefly extract with ATP to produce luminescence.…”

mentioning

confidence: 96%

Effects of divalent ions on vesicle-vesicle fusion studied by a new luminescence assay for fusion

Holz

Stratford

1979

J. Membrain Biol.

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Summary.A new assay has been developed for vesicle-vesicle fusion based upon the mixing of intravesicular contents of two sets of vesicles. Purified firefly luciferase and MgC12 were incorporated into one set of vesicles (LV) and ATP into the other (AV). Vesicles were prepared from soybean phospholipids. The luminescence that resulted from hydrolysis of ATP by luciferase was measured to determine the extent of mixing of the intravesicular contents. In the absence of divalent ions, incubation of a mixture of LV and AV did not produce luminescence. However, if Ca + § or other divalent ions were present at miltimolar concentrations, luminescence occurred. The luminescence did not result from extravesicular reaction of vesicle contents that had leaked into the medium. Instead, luminescence resulted from the mixing of intravesicular spaces of AV and LV in fused vesicles. Optical density changes and negative stain electron microscopy indicated that Ca § + induced extensive aggregation of vesicles. However, quantitation of the maximum possible luminescence indicates that only a small percentage (less than 1%) of the vesicles actually fused in a fusion experiment.Addition of EDTA to chelate Ca ++ after luminescence had been induced resulted in a two-to threefold increase in light emission which then rapidly decayed. These results suggest that the sudden removal of Ca § § caused a transient increase in fusion after which subsequent fusion was inhibited. It was also found that the vesicles were relatively stable to hypotonic solutions.

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Membrane fusion: studies with a calcium-sensitive dye, arsenazo III, in liposomes.

Cited by 23 publications

References 28 publications

Plasma Levels of Main Granulocyte Components during Hemodialysis: Effects of Immunosuppression

Plasma Levels of Main Granulocyte Components during Hemodialysis: Effects of Immunosuppression

Fusion of dipalmitoylphosphatidylcholine vesicles

Effects of divalent ions on vesicle-vesicle fusion studied by a new luminescence assay for fusion

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