The use of membrane-active compounds to examine the structure of the surface membrane of Schistosoma mansoni

1981 ◽  
Vol 1 (3) ◽  
pp. 253-261 ◽  
Author(s):  
J. R. Kusel ◽  
L. Stones ◽  
W. Harnett

The effects of. a variety of lipophilic compounds on the young stage (schistosomulum) and adult Schistosoma mansoni have been studied by measuring the release of51Cr and125I-labelled wheat-germ agglutinin from labelled parasites. The compounds could be classified into three groups, one of which described reagents which affected only the schistosomulum. It is concluded that during development, changes occur in the organization of the lipid phase of the parasite membrane

Parasitology ◽  
1980 ◽  
Vol 81 (1) ◽  
pp. 1-15 ◽  
Author(s):  
A. J. G. Simpson ◽  
S. R. Smithers

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.


Parasitology ◽  
1992 ◽  
Vol 105 (1) ◽  
pp. 81-89 ◽  
Author(s):  
D. Moffat ◽  
J. R. Kusel

Fluorescent lipophilic compounds can be used to label the surface membrane of Schistosoma mansoni by adding the compound in small amounts of organic solvents to aqueous medium in vitro. Under these conditions it is difficult to follow routes of distribution of the label. Here we have absorbed nitrobenzoxadiazolamine methylamino–(NBD)–ceramides to positively charged Dowex beads, and incubated the labelled beads with living parasites. The NBD–ceramide transfers to the surface membrane as a patch 50–100 μm in diameter, after which the label can be seen localized in the gut and in a very concentrated form in organelles within the oesophageal gland cells. Subsequently the labelled compound can be found in organelles within other body cells, including subtegumental cells. We show that the labelled ceramide has been transported from the patch in the surface membrane through internal membrane systems to the destination in the gut and oesophageal gland and not transported through the gut via the external medium. A different pattern was observed when NBD–cholesterol was used. The pharynx was rapidly labelled when NBD–cholesterol was added in medium with or without serum or attached to red blood cells only. Diffuse labelling of the surface membrane and oesophageal gland occurred. We have demonstrated a novel route of lipid transport within the parasite. The route requires the surface membrane to have very specialized regions to facilitate such transport.


Parasitology ◽  
1988 ◽  
Vol 96 (1) ◽  
pp. 85-97 ◽  
Author(s):  
M. Foley ◽  
J. R. Kusel ◽  
P. B. Garland

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.


1989 ◽  
Vol 62 (02) ◽  
pp. 815 ◽  
Author(s):  
Marjorie B Zucker ◽  
Robert A Grant ◽  
Evelyn A Mauss

2006 ◽  
Vol 6 (9) ◽  
pp. 2959-2966 ◽  
Author(s):  
Na Zhang ◽  
Qineng Ping ◽  
Guihua Huang ◽  
Xiuzhen Han ◽  
Yanna Cheng ◽  
...  

Wheat germ agglutinin (WGA) modified liposomes and solid lipid nanoparticles (SLNs) were evaluated for improving intestinal absorption of insulin. In an in situ local intestinal perfusion experiment, formulations containing 100 IU/kg insulin were administered to the duodenum, jejunum, and ileum of fasted rats. As hypothesized, ileum was the best intestinal location for the absorption of insulin-containing liposomes. Serum insulin concentrations decreased for the various formulations in different absorption sites according to the following trends: Duodenum > ileum > jejunum for WGA-modified insulin-containing liposomes; duodenum > jejunum > ileum for WGA-modified insulin-containing SLNs; ileum > jejunum > duodenum for insulin-containing liposomes; ileum > duodenum > jejunum for insulin-containing SLNs; and duodenum ≥ ileum > jejunum for aqueous solution of insulin. These results imply that the nanoparticle type and delivery site were important factors with respect to increasing the bioavailability of insulin following oral administration. The proteolytic degradation as well as the epithelial permeability were primary determinants influcing insulin mucosal absorption.


2017 ◽  
Vol 95 (12) ◽  
pp. 937-947 ◽  
Author(s):  
M. Hinzmann ◽  
M. Lopes-Lima ◽  
F. Cerca ◽  
A. Correia ◽  
J. Machado ◽  
...  

Haemocytes play a major role in molluscs immunity. Functional studies are, however, impaired by limited available experimental tools to identify and sort distinct haemocyte populations. Therefore, using nonlethal methods, we aimed at evaluating whether lectin staining combined with flow cytometry could be used to distinguish circulating haemocyte populations from two freshwater bivalves of the family Unionidae, the duck mussel (Anodonta anatina (L., 1758)) and the swan mussel (Anodonta cygnea (L., 1758)). Based on classical classification, haemocytes were distinguished as granulocytes and hyalinocytes and cytological features were visualized using transmission microscopy and staining techniques. Size, granularity, viability, and surface staining using lectins as specific probes were analysed by flow cytometry and fluorescence microscopy. The microscopic proportions of granulocytes and hyalinocytes significantly differed, being of 70% and 30% for A. cygnea and of 85% and 15% for A. anatina, respectively. Two haemocyte populations were sorted by flow cytometry based on size and granularity and confirmed as granulocytes and hyalinocytes. Interestingly, two different granulocyte populations could be further discriminated in A. cygnea according to their binding affinity to wheat-germ agglutinin (WGA), whereas granulocytes of A. anatina all stained similarly. Our results show that WGA labelling combined with flow cytometry can be used to better discriminate Anodonta haemocyte populations and obtain purified populations for functional studies.


Parasitology ◽  
1977 ◽  
Vol 74 (1) ◽  
pp. 73-86 ◽  
Author(s):  
Linda H. Brink ◽  
Diane J. McLaren ◽  
S. R. Smithers

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.


1985 ◽  
Vol 132 (1) ◽  
pp. 313-319 ◽  
Author(s):  
Chhanda L. Ganguly ◽  
Mohanathasan Chelladurai ◽  
Pankaj Ganguly

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