Influence of mechanical tail-detachment techniques of schistosome cercariae on the production, viability, and infectivity of resultant schistosomula: a comparative study

Gold, Daniel; Flescher, Eliezer

doi:10.1007/s004360000199

Cited by 14 publications

(6 citation statements)

References 15 publications

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“…Furthermore, there was no motion during a continuous 30 s observation. The viability assessment was ensured by methylene blue (MB) uptake testing after observation with the unstained schistosomula considered dead and the stained ones alive ( Gold & Flescher 2000 ).…”

Section: Methodsmentioning

confidence: 99%

A Microtus fortisprotein, serum albumin, is a novel inhibitor of Schistosoma japonicumschistosomula

Xiong

et al. 2013

Mem. Inst. Oswaldo Cruz

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Schistosomiasis is an endemic parasite disease and praziquantel is the only drug currently in use to control this disease. Experimental and epidemiological evidence strongly suggests that Microtus fortis ( Mf ) is a naturally resistant vertebrate host of Schistosoma japonicum . In the present study, we found that Mf serum albumin ( Mf -albumin) and the conditioned medium of pcDNA3.1- Mf -albumin caused 46.2% and 38.7% schistosomula death rates in 96 h, respectively, which were significantly higher than that of the negative control (p < 0.05). We also found that mice injected with Mf -albumin had a 43.5% reduction in worm burden and a 48.1% reduction in liver eggs per gram (p < 0.05) in comparison to the control animals. To characterise the mechanisms involved in clearance, schistosomula were incubated with fluorescein isothiocyanate-labelled Mf -albumin and fluorescent enrichment effects were found in the gut lumen of schistosomula after 48 h of incubation. Next, digestive tract excretions from schistosomula were collected and the sensitivity of Mf -albumin to digestive tract excretions was evaluated. The results indicated that schistosomula digestive tract excretions showed indigestibility of Mf -albumin. The death of schistosomula could be partially attributed to the lack of digestion of Mf -albumin by digestive tract excretions during the development of the schistosomula stage. Therefore, these data indicate the potential of Mf -albumin as one of the major selective forces for schistosomiasis.

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Section: Methodsmentioning

confidence: 99%

A Microtus fortisprotein, serum albumin, is a novel inhibitor of Schistosoma japonicumschistosomula

Xiong

et al. 2013

Mem. Inst. Oswaldo Cruz

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“…Heat-inactivated serum served as a control. The mortality of the schistosomula was assessed under an inverted microscope on the basis of motility and granularity data (19). Experiments were run in triplicate.…”

Section: Methodsmentioning

confidence: 99%

Inhibition of the Complement Membrane Attack Complex bySchistosoma mansoniParamyosin

Deng¹,

Gold²,

LoVerde

et al. 2003

Infect Immun

100

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Following partial purification and analysis by mass spectrometry, we have determined SCIP-1 to be a surface-exposed form of the muscle protein paramyosin. As shown by immunofluorescence, anti-paramyosin antibodies label the surface of live schistosomula and adult worms. Like SCIP-1, purified native paramyosin reacts with a polyclonal rabbit anti-human CD59 antiserum, as shown by Western blot analysis. Also, the human complement components C8 and C9 bind to recombinant and native paramyosin. Analysis of paramyosin binding to fragments of C9 generated by thrombin or trypsin has demonstrated that paramyosin binds to C9 at a position located between Gly245 and Arg391. Paramyosin inhibited Zn 2؉ -induced C9 polymerization and poly-C9 deposition onto rabbit erythrocytes (E R ). In addition, paramyosin inhibited lysis of E R and of sensitized sheep erythrocytes by human complement. Finally, anti-paramyosin antibodies enhanced in vitro killing of schistosomula by normal and C4-depleted human complement. Taken together, these findings suggest that an exogenous form of S. mansoni paramyosin inhibits activation of the terminal pathway of complement and thus has an important immunomodulatory role in schistosomiasis.Schistosomiasis is one of the most prevalent parasitic diseases, affecting over 200 million people who live in areas of endemicity in Africa, South America, and Asia (12). Schistosoma mansoni, one of the causative agents of this disease, resides within patients' mesenteric and portal blood systems and successfully evades host immune responses (43). During skin penetration into the mammalian host and shortly afterwards, the larvae convert from exhibiting sensitivity to complement-mediated killing to bearing resistance to complementmediated killing (32, 49). The first step in that conversion is the removal of the glycocalyx coat that contains strong complement activators. Subsequently, the transformed schistosomula and the adult worms employ several strategies to evade the host's complement system (14), thus enabling the parasite to reside for years within the host's circulatory system in direct contact with complement proteins. This parasite contains proteins that bind in vitro to the complement proteins C1 (25) and C2 (22) and C8 and C9 (40) and may thus block the complement cascade at multiple steps. Paramyosin, one of the inhibitory proteins, was shown to bind in vitro to C1q and inhibit C1 and the classical pathway of complement activation (25). Paramyosin is in essence an invertebrate muscle protein (11) that serves as a major component of the thick filament and is thought to play an important role in certain specialized contractile states (7, 23). It has also been found to be an immunogen during infection of mice and humans with helminth parasites (27,37,47). A nonfilamentous membrane-bound form of paramyosin was also found in the tegumental outer layer (16, 33) and on the surface (18, 31) of S. mansoni schistosomes. Analyzed on the basis of its capacity to bind to Fc (31), it has been suggested to have immu...

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“…Infected Biomphalaria glabrata snails were obtained from the Biomedical Research Institute, Rockville, Maryland, USA (Lewis et al, 1986) and were induced to shed cercariae approximately 45 days post-infection by exposure to continuous light for 30 min at room temperature. For cercarial transformation and culturing of schistosomula we modified the original Basch protocol (Basch, 1981) as follows: Cercariae were collected by cooling at 4 °C for 3 h and then vortexed at maximal speed for 2 min to detach the tails (Ramalho-Pinto et al, 1974; Gold and Flescher, 2000). The latter were subsequently removed by adding 70% Percoll (Sigma, Oakville, Ontario, Canada) prepared in minimal essential medium MEM (Gibco, Invitrogen, Canada) followed by centrifugation at 1700 rpm for 10 min at 5 °C.…”

Section: Methodsmentioning

confidence: 99%

Developmental expression analysis and immunolocalization of a biogenic amine receptor in Schistosoma mansoni

El-Shehabi¹,

Vermeire²,

Yoshino³

et al. 2009

Experimental Parasitology

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A Schistosoma mansoni G-protein coupled receptor (SmGPCR) was previously cloned and shown to be activated by the biogenic amine, histamine. Here we report a first investigation of the receptor’s subunit organization, tissue distribution and expression levels in different stages of the parasite. A polyclonal antibody was produced in rabbits against the recombinant third intracellular loop (il3) of SmGPCR. Western blot studies of the native receptor and recombinant protein expressed in HEK293 cells showed that SmGPCR exists both as a monomer (65 kDa) and an apparent dimer of ≈130 kDa These species were verified by immunoprecipitation of SmGPCR from S. mansoni extracts, using antibody that was covalently attached to agarose beads. Further investigation determined that the SmGPCR dimer was resistant to treatment with various detergents, 4 M urea and 0.1 M DTT but could be made to dissociate at acidic pH, suggesting the dimer is non-covalent in nature. Confocal immunofluorescence studies revealed significant SmGPCR immunoreactivity in sporocysts, schistosomula and adult worms but not miracidia. SmGPCR was found to be most widely expressed in the schistosomula, particularly the tegument, the subtegumental musculature and the acetabulum. In the adult stage we detected SmGPCR immunofluorescence mainly in the tubercles of male worms and, to a lesser extent, the body wall musculature. Localization in sporocysts was mainly confined to the tegument and cells within parenchymal matrices. A realtime quantitative reverse-transcription PCR analysis revealed that SmGPCR is upregulated at the mRNA level in the parasitic stages compared to the free-living miracidium and cercariae, and it is particularly elevated during early sporocyst and schistosomula development. The results identify SmGPCR as an important parasite receptor with potential functions in muscle and the tegument of S. mansoni.

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Influence of mechanical tail-detachment techniques of schistosome cercariae on the production, viability, and infectivity of resultant schistosomula: a comparative study

Cited by 14 publications

References 15 publications

A Microtus fortisprotein, serum albumin, is a novel inhibitor of Schistosoma japonicumschistosomula

A Microtus fortisprotein, serum albumin, is a novel inhibitor of Schistosoma japonicumschistosomula

Inhibition of the Complement Membrane Attack Complex bySchistosoma mansoniParamyosin

Developmental expression analysis and immunolocalization of a biogenic amine receptor in Schistosoma mansoni

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