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.

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.

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.

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)

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.

scholarly journals Shadowing the Actions of a Predator: Backlit Fluorescent Microscopy Reveals Synchronous Nonbinary Septation of Predatory Bdellovibrio inside Prey and Exit through Discrete Bdelloplast Pores

2010 ◽  
Vol 192 (24) ◽  
pp. 6329-6335 ◽  
Author(s):  
A. K. Fenton ◽  
M. Kanna ◽  
R. D. Woods ◽  
S.-I. Aizawa ◽  
R. E. Sockett
Keyword(s):  
Cell Division ◽  
Outer Membrane ◽  
Fluorescent Microscopy ◽  
Gram Negative Bacteria ◽  
Bacterial Cell Division ◽  
Prey Cell ◽  
Gram Negative ◽  
A Genome ◽  
Predatory Bacteria ◽  
First Time

ABSTRACT The Bdellovibrio are miniature “living antibiotic” predatory bacteria which invade, reseal, and digest other larger Gram-negative bacteria, including pathogens. Nutrients for the replication of Bdellovibrio bacteria come entirely from the digestion of the single invaded bacterium, now called a bdelloplast, which is bound by the original prey outer membrane. Bdellovibrio bacteria are efficient digesters of prey cells, yielding on average 4 to 6 progeny from digestion of a single prey cell of a genome size similar to that of the Bdellovibrio cell itself. The developmental intrabacterial cycle of Bdellovibrio is largely unknown and has never been visualized “live.” Using the latest motorized xy stage with a very defined z-axis control and engineered periplasmically fluorescent prey allows, for the first time, accurate return and visualization without prey bleaching of developing Bdellovibrio cells using solely the inner resources of a prey cell over several hours. We show that Bdellovibrio bacteria do not follow the familiar pattern of bacterial cell division by binary fission. Instead, they septate synchronously to produce both odd and even numbers of progeny, even when two separate Bdellovibrio cells have invaded and develop within a single prey bacterium, producing two different amounts of progeny. Evolution of this novel septation pattern, allowing odd progeny yields, allows optimal use of the finite prey cell resources to produce maximal replicated, predatory bacteria. When replication is complete, Bdellovibrio cells exit the exhausted prey and are seen leaving via discrete pores rather than by breakdown of the entire outer membrane of the prey.

A comparative study of the reproductive system of mature, immature and ‘unisexual’ female Schistosoma mansoni

Parasitology ◽  
1973 ◽  
Vol 67 (2) ◽  
pp. 165-183 ◽  
Author(s):  
David A. Erasmus
Keyword(s):  
Comparative Study ◽  
Schistosoma Mansoni ◽  
Reproductive System ◽  
Gland Cell ◽  
Female Worm ◽  
Cortical Granules ◽  
Posterior Portion ◽  
Vitelline Duct ◽  
Vitelline Cells ◽  
Pass Through

The ultrastructure of the reproductive system of mature (54-day-old), immature (32-day-old) and females from unisexual infections of Schistosoma mansoni is described in detail. The uterus is tegumentary in structure but the vitelline duct and oviduct are complex and possess cilia as well as lamellae on their luminal surfaces. The characteristics of the cells forming the walls of the ducts suggests that they may have a digestive function. The posterior portion of the oviduct of the adult worm contains sperm which become enveloped by lamellae. The vitelline cells of the adult contain vitelline droplets, much lipid and little glycogen. A second type of body derived from endoplasmic whorls is also present. Mehlis's gland contains only one type of gland cell and these cells pass through the ootype wall and open into its lumen. The female from unisexual infections has an incompletely developed Mehlis's gland, an ovary in which the Golgi complexes do not produce typical cortical granules and has vitelline cells which remain immature. The oviduct, ootype and uterus are well developed in contrast to the vitelline duct. A comparison with young, but not inseminated worms, suggests that the presence of sperm in the oviduct is not the major stimulus which induces maturation of the female worm.

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

scholarly journals Plant defensin antibacterial mode of action against Pseudomonas species

2020 ◽  
Author(s):  
Andrew Edward Sathoff ◽  
Shawn Lewenza ◽  
Deborah A. Samac
Keyword(s):  
Gene Expression ◽  
Antibacterial Activity ◽  
Outer Membrane ◽  
Pseudomonas Syringae ◽  
Mode Of Action ◽  
Fluorescent Microscopy ◽  
Insertion Site ◽  
Membrane Damage ◽  
Plant Defensin ◽  
Plant Defensins

Abstract Background: Though many plant defensins exhibit antibacterial activity, little is known about their antibacterial mode of action (MOA). Antimicrobial peptides with a characterized MOA induce the expression of multiple bacterial outer membrane modifications, which are required for resistance to these membrane-targeting peptides. Mini-Tn5-lux mutant strains of Pseudomonas aeruginosa with Tn insertions disrupting outer membrane protective modifications were assessed for sensitivity against plant defensin peptides. These transcriptional lux reporter strains were also evaluated for lux gene expression in response to sublethal plant defensin exposure. Also, a plant pathogen, Pseudomonas syringae pv. syringae was modified through transposon mutagenesis to create mutants that are resistant to in vitro MtDef4 treatments.Results: Plant defensins displayed specific and potent antibacterial activity against strains of P. aeruginosa. A defensin from Medicago truncatula, MtDef4, induced dose-dependent gene expression of the aminoarabinose modification of LPS and surface polycation spermidine production operons. The ability for MtDef4 to damage bacterial outer membranes was also verified visually through fluorescent microscopy. Another defensin from M. truncatula, MtDef5, failed to induce lux gene expression and limited outer membrane damage was detected with fluorescent microscopy. The transposon insertion site on MtDef4 resistant P. syringae pv. syringae mutants was sequenced, and modifications of ribosomal genes were identified to contribute to enhanced resistance to plant defensin treatments. Conclusions: MtDef4 damages the outer membrane similar to polymyxin B, which stimulates antimicrobial peptide resistance mechanisms to plant defensins. MtDef5, appears to have a different antibacterial MOA. Additionally, the MtDef4 antibacterial mode of action may also involve inhibition of translation.

scholarly journals Functional diversity of isoprenoidal lipids in Methylobacterium extorquens PA1

2020 ◽  
Author(s):  
Sandra Rizk ◽  
Petra Henke ◽  
Carlos Santana-Molina ◽  
Gesa Martens ◽  
Marén Gnädig ◽  
...  
Keyword(s):  
Outer Membrane ◽  
Surface Membrane ◽  
Chemical Properties ◽  
Carotenoid Biosynthesis ◽  
Membrane Lipid ◽  
Cellular Growth ◽  
Membrane Properties ◽  
Methylobacterium Extorquens ◽  
Ideal System ◽  
Eukaryotic Organisms

AbstractHopanoids and carotenoids are two of the major isoprenoid-derived lipid classes in prokaryotes that have been proposed to have similar membrane ordering properties as sterols. Methylobacterium extorquens contains hopanoids and carotenoids in their outer membrane, making them an ideal system to investigate whether isoprenoid lipids play a complementary role in outer membrane ordering and cellular fitness. By genetically knocking out hpnE, and crtB we disrupted the production of squalene, and phytoene in Methylobacterium extorquens PA1, which are the presumed precursors for hopanoids and carotenoids, respectively. Deletion of hpnE unexpectedly revealed that carotenoid biosynthesis utilizes squalene as a precursor resulting in a pigmentation with a C30 backbone, rather than the previously predicted C40 phytoene-derived pathway. We demonstrate that hopanoids but not carotenoids are essential for growth at high temperature. However, disruption of either carotenoid or hopanoid synthesis leads to opposing effects on outer membrane lipid packing. These observations show that hopanoids and carotenoids may serve complementary biophysical roles in the outer membrane. Phylogenetic analysis suggests that M. extorquens may have acquired the C30 pathway through lateral gene transfer with Planctomycetes. This suggests that the C30 carotenoid pathway may have provided an evolutionary advantage to M. extorquens.ImportanceAll cells have a membrane that delineates the boundary between life and its environment. To function properly, membranes must maintain a delicate balance of physical and chemical properties. Lipids play a crucial role in tuning membrane properties. In eukaryotic organisms from yeast to mammals, sterols are essential for assembling a cell surface membrane that can support life. However, bacteria generally do not make sterols, so how do they solve this problem? Hopanoids and carotenoids are two major bacterial lipids, that are proposed as sterol surrogates. In this study we explore the bacterium M. extorquens for studying the role of hopanoids and carotenoids in surface membrane properties and cellular growth. Our findings suggest that hopanoids and carotenoids may serve complementary roles balancing outer membrane properties, and provide a foundation for elucidating the principles of surface membrane adaptation.

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