scholarly journals The lateral diffusion of lipid probes in the surface membrane of Schistosoma mansoni.

1986 ◽  
Vol 103 (3) ◽  
pp. 807-818 ◽  
Author(s):  
M Foley ◽  
A N MacGregor ◽  
J R Kusel ◽  
P B Garland ◽  
T Downie ◽  
...  
Keyword(s):  
Schistosoma Mansoni ◽  
Fluorescence Recovery After Photobleaching ◽  
Surface Membrane ◽  
Biological Significance ◽  
Lateral Diffusion ◽  
Asymmetric Distribution ◽  
Normal Surface ◽  
Membrane Blebs ◽  
Fluorescent Lipids ◽  
Fluorescent Lipid Analogues

The technique of fluorescence recovery after photobleaching was used to measure the lateral diffusion of fluorescent lipid analogues in the surface membrane of Schistosoma mansoni. Our data reveal that although some lipids could diffuse freely others exhibited restricted lateral diffusion. Quenching of lipid fluorescence by a non-permeant quencher, trypan blue, showed that there was an asymmetric distribution of lipids across the double bilayer of mature parasites. Those lipids that diffused freely were found to reside mainly in the external monolayer of the outer membrane whereas lipids with restricted lateral diffusion were located mainly in one or more of the monolayers beneath the external monolayer. Formation of surface membrane blebs allowed us to measure the lateral diffusion of lipids in the membrane without the influence of underlying cytoskeletal structures. The restricted diffusion found on the normal surface membrane of mature parasites was found to be released in membrane blebs. Quenching of fluorescent lipids on blebs indicated that all probes were present almost entirely in the external monolayer. Juvenile worms exhibited lower lateral diffusion coefficients than mature parasites: in addition, the lipids partitioned into the external monolayer. The results are discussed in terms of membrane organization, cytoskeletal contacts, and biological significance.

Distribution and biophysical properties of fluorescent lipids on the surface of adult Schistosoma mansoni

Parasitology ◽  
1996 ◽  
Vol 113 (2) ◽  
pp. 137-143 ◽  
Author(s):  
C. A. Redman ◽  
J. R. Kusel
Keyword(s):  
Schistosoma Mansoni ◽  
Outer Membrane ◽  
Adult Male ◽  
Surface Membrane ◽  
Fluorescent Microscopy ◽  
Biophysical Properties ◽  
Fluorescent Lipids ◽  
Pass Through ◽  
Lipid Compounds ◽  
Outer Monolayer

SUMMARYThe properties of 4 fluorescent lipid compounds in the surface membrane of adult male Schistosoma mansoni worms were examined by fluorescent microscopy and fluorescent recovery after photobleaching (FRAP). The data suggest that the probes N-(4,4-difluoro-5,7-dimethyl-4-bora-3a,4a-diaza-s-indacene-3-pentanoyl) sphingosine (BODIPY FL ceramide) and PKH2 pass through the outer membrane and enter structures in or below the membrane. In contrast 5-(N-octadecanoyl)aminofluorescein (AF18) and N-(4,4-difluoro-5,7-dimethyl-4-bora-3a,4a-diaza-s-indacene-3-pentanoyl) sphingosylphosphocholine (BODIPY FL sphingomyelin) insert into the outer monolayer. The DL values of these latter 2 compounds, 8·83 ± 2·35 × 10−9 cm2 s−1 and 2·76 ± 0·53 × 10−9cm2 s−1, respectively, suggest that they enter different domains. Furthermore, it was observed that both BODIPY FL ceramide and BODIPY FL sphingomyelin entered particular structures in or under the surface membrane. The possible nature of these particles is discussed.

Changes in the organization of the surface membrane upon transformation of cercariae to schistosomula of the helminth parasite Schistosoma mansoni

Parasitology ◽  
1988 ◽  
Vol 96 (1) ◽  
pp. 85-97 ◽  
Author(s):  
M. Foley ◽  
J. R. Kusel ◽  
P. B. Garland
Keyword(s):  
Schistosoma Mansoni ◽  
Crystalline Phase ◽  
Liquid Crystalline ◽  
Fluorescence Recovery After Photobleaching ◽  
Surface Membrane ◽  
Skin Penetration ◽  
Membrane Lipid ◽  
Lipid Phase ◽  
Entire Surface ◽  
Fluorescent Compound

SUMMARYMerocyanin 540 (Mc540) is a fluorescent compound which is thought to bind to membranes in which there are substantial amounts of lipid in the lipid-crystalline phase. It is shown here to be of value in detecting the transformation by both mechanical and skin-penetration methods of the cercaria to the schistosomulum. The cercaria does not appear to bind Mc540, but the schistosomulum, binds Mc540 initially, in its anterior region, and at later times over the entire surface. The suggestion that transformation involves changes in the surface membrane lipid phase from gel to liquid-crystalline phase is supported by fluorescence recovery after photobleaching results with 5-N-(octadecanoyl)-amino fluorescein, a lipophilic dye which appears to be immobile in the cercaria, but fully mobile in the 40 min schistosomulum.

Low density lipoproteins bound to Schistosoma mansoni do not alter the rapid lateral diffusion or shedding of lipids in the outer surface membrane

1991 ◽  
Vol 99 (1) ◽  
pp. 167-173
Author(s):  
J.P. Caulfield ◽  
C.P. Chiang ◽  
P.W. Yacono ◽  
L.A. Smith ◽  
D.E. Golan
Keyword(s):  
Schistosoma Mansoni ◽  
Outer Membrane ◽  
De Novo ◽  
Acyl Chain ◽  
Surface Membrane ◽  
Lateral Diffusion ◽  
Low Density Lipoproteins ◽  
Low Density ◽  
Lateral Mobility ◽  
Ldl Binding

Schistosomula of Schistosoma mansoni bind human low density lipoproteins (LDL) in a concentration-dependent and saturable manner. The bound LDL could provide phospholipids and sterol to the worm, which cannot synthesize sterol de novo and lacks acyl chain-modifying capability. Here we have used three phospholipid analogues to explore the effect of LDL binding on the parasite's outer tegumental membrane, i.e. the outer of the two membranes that cover its surface syncytium. Fluorescein phosphatidylethanolamine (Fl-PE) and rhodamine phosphatidylethanolamine (Rh-PE) bound to the parasite in a saturable manner and, as shown by fluorescence microscopy, were confined to the surface. Fl-PE fluorescence was completely quenched by Trypan Blue and Fl-PE was lost from the surface following single exponential decay kinetics (t1/2 = 12 h), further suggesting that the probe was confined to the outer membrane. 1,1′-Dioctadecyl-3,3,3′,3′-tetramethyl-indocarbocyanine perchlorate (DiI-C18(3); DiI) did not bind saturably and was seen in both the surface and the internal parasite membranes. Fluorescence photobleaching recovery was used to measure the lateral mobility of Fl-PE in the outer membrane. The lateral diffusion coefficient of Fl-PE was approximately 10(−7) cm2s-1. The fractional mobility of Fl-PE was 85% when measured using a laser beam of radius 1.8 microns and 45% using a beam of radius 4.3 microns. These measurements suggest that the outer membrane is composed of micron-scale liquid crystalline-phase lipid domains that lack significant amounts of transmembrane proteins. LDL binding to the parasite surface did not alter the lateral mobility of Fl-PE or the rate of loss of either Fl-PE or Rh-PE.(ABSTRACT TRUNCATED AT 250 WORDS)

The organization of cell surface membrane domains

1989 ◽  
Vol 47 ◽  
pp. 804-805
Author(s):  
Michael Edidin
Keyword(s):  
Cell Surface ◽  
Membrane Lipids ◽  
Surface Membrane ◽  
Lateral Diffusion ◽  
Cell Types ◽  
Membrane Domains ◽  
Membrane Biology ◽  
Morphological Polarity ◽  
Discrete Domains ◽  
Membrane Components

Cell surface membranes are based on a fluid lipid bilayer and models of the membranes' organization have emphasised the possibilities for lateral motion of membrane lipids and proteins within the bilayer. Two recent trends in cell and membrane biology make us consider ways in which membrane organization works against its inherent fluidity, localizing both lipids and proteins into discrete domains. There is evidence for such domains, even in cells without obvious morphological polarity and organization [Table 1]. Cells that are morphologically polarised, for example epithelial cells, raise the issue of membrane domains in an accute form.The technique of fluorescence photobleaching and recovery, FPR, was developed to measure lateral diffusion of membrane components. It has also proven to be a powerful tool for the analysis of constraints to lateral mobility. FPR resolves several sorts of membrane domains, all on the micrometer scale, in several different cell types.

Schistosoma mansoni: a comparative study of artificially transformed schistosomula and schistomula recoverd after cercarial penetration of isolated skin

Parasitology ◽  
1977 ◽  
Vol 74 (1) ◽  
pp. 73-86 ◽  
Author(s):  
Linda H. Brink ◽  
Diane J. McLaren ◽  
S. R. Smithers
Keyword(s):  
Comparative Study ◽  
Schistosoma Mansoni ◽  
Amorphous Material ◽  
Surface Membrane ◽  
Antigenic Determinants ◽  
Agglutination Reaction ◽  
Rat Serum ◽  
Mechanical Separation ◽  
B Blood Group

A comparison was made of the ultrastructure, development and antigenic nature of the surfaces and of the viability of three types of schistosomula of Schistosoma mansoni: schistosomula formed afrer cercariae had penetrated isolated skin (SS), schistosomula produced after mechanical separation of cercarial tails from bodies (MS), and schistosomula transformed from cercariae after incubation in fresh rat serum (RS).Within 2 h of transformation, the surface membrane of all three types of schistosomula had changed from trilaminate to heptalaminate structures and SS and MS had lost their cercarial glycocalyx. Initially a dense amorphous material was demonstrated on the surfaces of RS, which was thought to be the result of an interaction between a factor in rat serum and the glycocalyx: this material was greatly reduced within 2 h of transformation. The pre-acetabular glands of SS were emptied while those of MS and RS retained their contents. Immunofluorescent studies showed that all schistosomula bound serum from mice immune to S. mansoni, but the binding was stronger with MS and RS. The mixed agglutination reaction demonstrated the presence of human A and B blood group-like antigenic determinants on approximately 30% of 3 h old SS; these determinants were not detected on MS or RS. In vitro, the development of MS and RS was similar to SS; the first schistosomula reached the ‘gut-closed’ stage by day 10; 50–70% of SS reached this stage by day 12, in contrast to only 25–50% of MS and RS. Between 28 and 45% of all schistosomula developed to maturity when injected intravenously into mice.It was concluded that the two types of artificially prepared schistosomula fultil the main criteria of transformation from cercaria to schistosomulum. Further, it is suggested that MS are the most appropriate source of material for immunochemical and physiological studies.

Lateral Mobility of Integrin αIIbβ3 (Glycoprotein IIb/IIIa) in the Plasma Membrane of a Human Megakaryocyte

1997 ◽  
Vol 77 (01) ◽  
pp. 143-149 ◽  
Author(s):  
Annelies Schootemeijer ◽  
Gijsbert van Willigen ◽  
Hans van der Vuurst ◽  
Leon G J Tertoolen ◽  
Siegfried W De Laat ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Fluorescence Recovery After Photobleaching ◽  
Cell Activation ◽  
Lateral Diffusion ◽  
Cytochalasin D ◽  
Lag Phase ◽  
Integrin Αiibβ3 ◽  
Cell Matrix ◽  
Cytoplasmic Actin ◽  
Mobile Fraction

SummaryThe migration of integrins to sites of cell-cell and cell-matrix contact is thought to be important for adhesion strengthening. We studied the lateral diffusion of integrin αIIbβ3 (glycoprotein Ilb/IIIa) in the plasma membrane of a cultured human megakaryocyte by fluorescence recovery after photobleaching of FITC-labelled monovalent Fab fragments directed against the P3 subunit. The diffusion of P3 on the unstimulated megakaryocyte showed a lateral diffusion coefficient (D) of 0.37 X10'9 cm2/s and a mobile fraction of about 50%. Stimulation with ADP (20 μM) or α-thrombin (10 U/ml) at 22° C induced transient decreases in both parameters reducing D to 0.21 X 10‘9 cm2/s and the mobile fraction to about 25%. The fall in D was observed within 1 min after stimulation but the fall in mobile fraction showed a lag phase of 5 min. The lag phase was absent in the presence of Calpain I inhibitor, whereas cytochalasin D completely abolished the decrease in mobile fraction. The data are compatible with the concept that cell activation induces anchorage of 50% of the mobile αIIbβ3 (25% of the whole population of receptor) to the cytoplasmic actin filaments, although, as discussed, other rationals are not ruled out.

Identification by monoclonal antibody of a major (28 kDa) surface membrane antigen of Schistosoma mansoni

1985 ◽  
Vol 16 (3) ◽  
pp. 345-354 ◽  
Author(s):  
Donald A. Harn ◽  
Masao Mitsuyama ◽  
Edward D. Huguenel ◽  
Lynette Oligino ◽  
John R. David
Keyword(s):  
Monoclonal Antibody ◽  
Schistosoma Mansoni ◽  
Surface Membrane

Characterization of the exposed carbohydrates on the surface membrane of adult Schistosoma mansoni by analysis of lectin binding

Parasitology ◽  
1980 ◽  
Vol 81 (1) ◽  
pp. 1-15 ◽  
Author(s):  
A. J. G. Simpson ◽  
S. R. Smithers
Keyword(s):  
Schistosoma Mansoni ◽  
Adult Male ◽  
Wheat Germ ◽  
Ricinus Communis ◽  
Specific Binding ◽  
Lectin Binding ◽  
Surface Membrane ◽  
Soybean Agglutinin ◽  
Peanut Agglutinin

SUMMARYThe surface architecture of adult male Schistosoma mansoni was explored using a range of lectins with differing carbohydrate specificities. Highest specific binding was achieved with concanavalin A and the agglutinin of molecular weight 60000 from Ricinus communis; the binding of wheat germ agglutinin was mostly non-specific. Small amounts of peanut agglutinin and soybean agglutinin binding were observed and the binding of these lectins was increased by pre-treating the parasite with neuraminidase. The fucose binding protein of Lotus tetragonolobus failed to bind. These results indicate that mannose and/or glucose, galactose, N-acetyl-glucosamine, N-acetyl-galactosamine and sialic acid are exposed on the surface of the adult male schistosome.

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