Schistosoma mansoni: evidence for a role of serum factors in protecting artificially transformed schistosomula against antibody-mediated killing in vitro

Parasitology ◽  
1978 ◽  
Vol 77 (2) ◽  
pp. 225-233 ◽  
Author(s):  
C. A. P. Tavares ◽  
Rita C. Soares ◽  
P. M. Z. Coelho ◽  
G. Gazzinelli

SummaryArtificially transformed schistosomula of Schistosoma mansoni develop a consistent but small protection against the lethal effects of antibody plus complement when cultured for 24 h in a chemically defined medium. In contrast, they become rapidly resistant to antibody plus complement, when cultured in the presence of a complex medium consisting of equal parts of heat-inactivated rabbit serum and Earle's/lactalbumin or in defined medium supplemented with small amounts of heat-inactivated rabbit serum. Sephadex G-200 gel filtration revealed that the protective factor in rabbit serum is a macromolecule with a molecular weight between 7 and 19S. Parasites cultured at 10 °C or in the presence of 200 μg of puromycin show less serum-induced protection against the lethal effects of antibody plus complement than do controls.

Parasitology ◽  
1980 ◽  
Vol 80 (1) ◽  
pp. 95-104 ◽  
Author(s):  
C. A. P. Tavares ◽  
M. N. Cordeiro ◽  
T. A. Mota-Santos ◽  
G. Gazzinelli

SummaryIncorporation of labelled amino acid into tegumental proteins and acquisition of protection by schistosomula against antibody-mediated killing in vitro were simultaneously stimulated by serum factors and inhibited by puromycin. Comparison of polyacrylamide gel electrophoresis patterns with fluorographic autoradiography indicates that the majority of proteins in the parasite tegument were labelled with the isotope after incubation for 3 h. No new, clearly defined band was observed in the autoradiography pattern. During this period a decreasing susceptibility of the schistosomula to antibody plus complement was observed. Quantitative fluorescence assay shows that schistosomula insensitive to antibody plus complement were still able to bind the same amount of antibody as the unprotected parasites. Pre-culture of schistosomula in the presence of inactivated normal rabbit serum also decreased the susceptibility of the parasites to the in vivo killing mechanism.


2021 ◽  
Vol 14 (7) ◽  
pp. 686
Author(s):  
Raquel Porto ◽  
Ana C. Mengarda ◽  
Rayssa A. Cajas ◽  
Maria C. Salvadori ◽  
Fernanda S. Teixeira ◽  
...  

The intravascular parasitic worm Schistosoma mansoni is a causative agent of schistosomiasis, a disease of great global public health significance. Praziquantel is the only drug available to treat schistosomiasis and there is an urgent demand for new anthelmintic agents. Adopting a phenotypic drug screening strategy, here, we evaluated the antiparasitic properties of 46 commercially available cardiovascular drugs against S. mansoni. From these screenings, we found that amiodarone, telmisartan, propafenone, methyldopa, and doxazosin affected the viability of schistosomes in vitro, with effective concentrations of 50% (EC50) and 90% (EC90) values ranging from 8 to 50 µM. These results were further supported by scanning electron microscopy analysis. Subsequently, the most effective drug (amiodarone) was further tested in a murine model of schistosomiasis for both early and chronic S. mansoni infections using a single oral dose of 400 mg/kg or 100 mg/kg daily for five consecutive days. Amiodarone had a low efficacy in chronic infection, with the worm and egg burden reduction ranging from 10 to 30%. In contrast, amiodarone caused a significant reduction in worm and egg burden in early infection (>50%). Comparatively, treatment with amiodarone is more effective in early infection than praziquantel, demonstrating the potential role of this cardiovascular drug as an antischistosomal agent.


PLoS ONE ◽  
2018 ◽  
Vol 13 (2) ◽  
pp. e0192884 ◽  
Author(s):  
Hiroyuki Sanjo ◽  
Mitsuru Komeya ◽  
Takuya Sato ◽  
Takeru Abe ◽  
Kumiko Katagiri ◽  
...  

1995 ◽  
Vol 219 (1) ◽  
pp. 211-222 ◽  
Author(s):  
Donald P. Lennon ◽  
Stephen E. Haynesworth ◽  
Randell G. Young ◽  
James E. Dennis ◽  
Arnold I. Caplan

1975 ◽  
Vol 21 (4) ◽  
pp. 521-527 ◽  
Author(s):  
Noritake Asato ◽  
Maria van Soestbergen ◽  
F William Sunderman

Abstract Binding of 63Ni(Il) to ultrafiltrable constituents of rabbit serum was studied (a) after in vitro incubation (2 h, 37 °C) of rabbit serum with 63NiCl2 (10-100 µmol/liter), and (b) at intervals (0.25-2 h) after in vivo administration of 63NiCl2 (40-160 µmol/kg body wt, i.v.). Serum ultrafiltrates were fractionated by thin-layer chromatography, and the separated compounds made visible by autoradiography and by ninhydrin staining. Several (≃5) ultrafiltrable 63Ni-complexes were demonstrable as distinct radiodense 63Ni-bands with chromatographic mobilities corresponding to those of ninhydrin-positive bands. Unbound 63Ni(II) was not detected in serum ultrafiltrates in either the in vitro or in vivo experiments. In sera (n = 10) incubated in vitro with 63Ni(II) (10 µmol/ liter), the mean percentage of ultrafiltrable 63Ni was 36% (range = 33-38) of total serum 63Ni. In contrast, in sera (n = 10) obtained 2 h after i.v. injection of 63Ni(II) (40 µmol/kg), the mean concentration of total serum 63Ni was 10.8 µmol/liter (range = 6-14), and the mean percentage of ultrafiltrable 63Ni was 15% (range = 9-21) of total serum 63Ni. The disparity between the percentages of ultrafiltrable 63Ni obtained in vitro and in vivo was obviated when the in vivo experiments were performed in rabbits bilaterally nephrectomized, with ligated common bile ducts. This investigation confirms the existence of several nickel receptors in serum ultrafiltrates and substantiates the role of ultrafiltrable complexes in the excretion of nickel.


2007 ◽  
Vol 19 (1) ◽  
pp. 215
Author(s):  
K. Yoshioka ◽  
M. Yokoo ◽  
T. Ozawa ◽  
C. Suzuki ◽  
H. Abe ◽  
...  

Hyaluronan (HA), a glycosaminoglycan present in follicular and oviductal fluids, has been related to sperm capacitation, fertilization, and embryo development. We have found that exogenous HA improves cell proliferation of porcine embryos cultured in a chemically defined medium (Yoshioka et al. 2004 Reprod. Fertil. Dev. 16, 264–265). Moreover, mitochondrial maturation was clearly more advanced in blastocysts cultured with HA compared to those cultured without HA, as seen by transmission electron microscopy. In the present study, the effects of HA on oxygen consumption and ATP content of blastocysts, produced in a defined system which reflects metabolic activity, were investigated. Porcine immature oocytes were matured for 44 h in porcine oocyte medium (POM) and subsequently fertilized with frozen–thawed ejaculated semen in porcine gamete medium supplemented with theophylline, adenosine, and cysteine (PGMtac4). Both POM and PGMtac4 were chemically defined media modified from porcine zygote medium (PZM)-5. After IVF, presumptive zygotes were cultured in PZM-5 containing HA (from the microorganism, Nacalai tesque, Kyoto, Japan) at concentrations of 0 [control], 10 [HA10], or 100 [HA100] �g mL-1 until 5 days after IVF. Blastocyst formation rate and total cell numbers/blastocyst at Day 5 were assessed. In addition, oxygen consumption and ATP content of single Day 5 blastocysts were measured. Blastocyst oxygen consumption was quantified using scanning electrochemical microscopy (HV-403; Research Institute for the Functional Peptides, Yamagata, Japan), and embryonic ATP content was determined using a commercial assay based on the luciferin-luciferase reaction (ATPlite; PerkinElmer, Groningen, The Netherlands). Data were statistically analyzed by ANOVA and Fisher's PLSD test. While the percentage of embryos that developed to the blastocyst stage [30.5% (63/206) to 31.7% (65/206)] did not differ among treatments, blastocyst cell number in the HA100 group [57.9 cells (n = 64)] was greater (P < 0.05) compared to those in the control [48.6 cells (n = 63)] or HA10 [50.0 cells (n = 65)] groups. Blastocyst oxygen consumption rate in the HA100 group [0.629 � 10-14 mol s-1 (n = 15)] was significantly higher than in the control [0.500 � 1-14 mol s-1 (n = 16)] or HA10 [0.464 � 10-14 mol s-1 (n = 14)] groups. ATP content/blastocyst did not differ among treatments [control: 0.645 pmol (n = 38), HA10: 0.727 pmol (n = 42), and HA100: 0.704 pmol (n = 43)]. It is concluded that HA affects the metabolic activity of pig blastocysts developed in a chemically defined medium, enhancing oxygen consumption and their total cell numbers, thus improving the quality of IVP blastocysts.


2013 ◽  
Vol 25 (1) ◽  
pp. 260
Author(s):  
H. Funahashi ◽  
Q.-S. Wu

Sperm capacitation, a cyclic-adenosine monophosphate-dependent phenomenon, is an important initiation step for penetration into oocytes. In porcine IVF, the use of caffeine, as a nonspecific phosphodiesterase (PDE) inhibitor, is common to accelerate sperm capacitation and penetration. The objective of this study was to examine the effects of PDE inhibitors (cilostamide, rolipram, and sildenafil as PDE type 3-, type 4-, and type 5-specific inhibitors, respectively) on the capacitation of boar sperm and the penetration into porcine oocytes in the absence of caffeine and other capacitation inducers in a chemically defined medium. After washing sperm samples collected from an ejaculated sperm-rich fraction of different individual Berkshires, the sperm were resuspended in capacitation inducer-free (theophylline- and adenosine-free) PGM-tac4 (mPGM-tac) at 5 × 105 cells mL–1. The suspension was cultured in mPGM-tac nonsupplemented or supplemented with 2.5 mM cilostamide, rolipram, or sildenafil for 90 min at 39°C in an atmosphere of 5% CO2 in air, and then the capacitation status was assessed by chlortetracycline fluorescence assay. Other sperm suspensions were used to co-culture with denuded in vitro-matured oocytes in the same medium for 8 h in an atmosphere of 5% CO2 in air and fixed, and sperm penetration was then examined. Statistical analyses of results from 4 replicated trials were performed by ANOVA with a Bonferroni-Dunn post hoc test (significance, P < 0.05). In our result from the chlortetracycline fluorescence assay, although the incidence of intact sperm was significantly reduced in the presence of rolipram (54.3%) and sildenafil (52.7%) as compared with controls (66.7%), there were no differences in capacitated sperm among experimental groups (24.3 to 34.3%). The incidence of acrosome-reacted sperm was higher in the presence of cilostamide (17.3%) than in the others (9.0 to 13.0%). High sperm penetration was observed only in the presence of sildenafil (76.6%) as compared with the control (0%) or the presence of rolipram (4.4%) or cilostamide (1.8%). These results demonstrate that inhibition of PDE type 5, but not PDE type 3 and type 4, significantly accelerates the penetration of boar sperm into the oocytes in a capacitation inducer-free chemically defined medium, whereas inhibition of PDE type 3 may induce an acrosome reaction.


1981 ◽  
Vol 60 (C) ◽  
pp. 1586-1586 ◽  
Author(s):  
H. C. Tenenbaum

Calvarial periostea were dissected from 17-day-old embryonic chicks and folded with the osteogenic cells in apposition. The folded explains were cultured for up to six d on serum and plasma clots or in serum-free hormone-supplemented completely-defined medium. Osteoid consistently formed in such cultures in both types of media, and this osteoid mineralized when appropriate levels of β-glycerophosphate were added to each type of medium. The data presented suggest that the levels of organic phosphate might be more important than inorganic phosphates as a limiting factor in the initiation of mineralization of bone in vitro.


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