How anthelmintics help us to understand helminths

Parasitology ◽  
1985 ◽  
Vol 90 (4) ◽  
pp. 675-685 ◽  
Author(s):  
H. Vanden Bossche
Keyword(s):  
Molecular Weight ◽  
Schistosoma Mansoni ◽  
Mode Of Action ◽  
Liver Fluke ◽  
Fasciola Hepatica ◽  
Atp Synthesis ◽  
Aerobic Metabolism ◽  
Unexpected Finding

Study of the mode of action of the anti-parasitic ‘hydrogenophore’, closantel, revealed that mitochondria isolated from livers of untreated rats, 13 weeks after infection with Fasciola hepatica metacercariae, were uncoupled. This uncoupling of mitochondria might be induced by a product(s) excreted by the liver fluke. The lipid extractable product(s) binds to albumin and has a molecular weight between 500 and 1000 Daltons. A second unexpected finding indicates that closantel affects the motility of Schistosoma mansoni in vitro by interferin with mitochondrial ATP synthesis. The results obtained are suggestive of a role for aerobic metabolism in the generation of energy required for motility.

Antigenicity of a proteolytic enzyme of Fasciola hepatica

1988 ◽  
Vol 62 (3) ◽  
pp. 257-260 ◽  
Author(s):  
G. C. Coles ◽  
D. Rubano
Keyword(s):  
Molecular Weight ◽  
Schistosoma Mansoni ◽  
Western Blotting ◽  
Gel Electrophoresis ◽  
Proteolytic Enzyme ◽  
Fasciola Hepatica

ABSTRACTThe possibility was examined of using a haemoglobinase released during in vitro incubation of adult Fasciola hepatica for immunodiagnosis of fascioliasis. By SDS gel electrophoresis the enzyme appeared as two closely migrating bands with a molecular weight of approximately 27 000 daltons. After Western blotting the bands reacted with serum from rats infected with F. hepatica and mice infected with Schistosoma mansoni. The enzyme was therefore not a good antigen for immunodiagnosis.

scholarly journals The soluble glutathione transferase superfamily: role of Mu class in triclabendazole sulphoxide challenge in Fasciola hepatica

2021 ◽  
Vol 120 (3) ◽  
pp. 979-991
Author(s):  
Rebekah B. Stuart ◽  
Suzanne Zwaanswijk ◽  
Neil D. MacKintosh ◽  
Boontarikaan Witikornkul ◽  
Peter M. Brophy ◽  
...  
Keyword(s):  
In Vitro Culture ◽  
Liver Fluke ◽  
Glutathione Transferase ◽  
Fasciola Hepatica ◽  
Affinity Purification ◽  
Economic Loss ◽  
Differential Abundance ◽  
Parasitic Helminths

AbstractFasciola hepatica (liver fluke), a significant threat to food security, causes global economic loss for the livestock industry and is re-emerging as a foodborne disease of humans. In the absence of vaccines, treatment control is by anthelmintics; with only triclabendazole (TCBZ) currently effective against all stages of F. hepatica in livestock and humans. There is widespread resistance to TCBZ and its detoxification by flukes might contribute to the mechanism. However, there is limited phase I capacity in adult parasitic helminths with the phase II detoxification system dominated by the soluble glutathione transferase (GST) superfamily. Previous proteomic studies have demonstrated that the levels of Mu class GST from pooled F. hepatica parasites respond under TCBZ-sulphoxide (TCBZ-SO) challenge during in vitro culture ex-host. We have extended this finding by exploiting a sub-proteomic lead strategy to measure the change in the total soluble GST profile (GST-ome) of individual TCBZ-susceptible F. hepatica on TCBZ-SO-exposure in vitro culture. TCBZ-SO exposure demonstrated differential abundance of FhGST-Mu29 and FhGST-Mu26 following affinity purification using both GSH and S-hexyl GSH affinity. Furthermore, a low or weak affinity matrix interacting Mu class GST (FhGST-Mu5) has been identified and recombinantly expressed and represents a new low-affinity Mu class GST. Low-affinity GST isoforms within the GST-ome was not restricted to FhGST-Mu5 with a second likely low-affinity sigma class GST (FhGST-S2) uncovered. This study represents the most complete Fasciola GST-ome generated to date and has supported the potential of subproteomic analyses on individual adult flukes.

scholarly journals Transcriptomic analysis reveals a role for the nervous system in regulating growth and development of Fasciola hepatica juveniles

2022 ◽  
Author(s):  
Emily Robb ◽  
Erin McCammick ◽  
Duncan Wells ◽  
Paul McVeigh ◽  
Erica Gardiner ◽  
...  
Keyword(s):  
Nervous System ◽  
Rapid Growth ◽  
Growth And Development ◽  
Liver Fluke ◽  
Fasciola Hepatica ◽  
Expression Profiles ◽  
Neuronal Signalling ◽  
Growth Development

Fasciola spp. liver fluke have significant impacts in veterinary and human medicine. The absence of a vaccine and increasing anthelmintic resistance threaten sustainable control and underscore the need for novel flukicides. Functional genomic approaches underpinned by in vitro culture of juvenile Fasciola hepatica facilitate control target validation in the most pathogenic life stage. Comparative transcriptomics of in vitro and in vivo maintained 21 day old F. hepatica finds that 86% of genes are expressed at similar levels across maintenance treatments suggesting commonality in core biological functioning within these juveniles. Phenotypic comparisons revealed higher cell proliferation and growth rates in the in vivo juveniles compared to their in vitro counterparts. These phenotypic differences were consistent with the upregulation of neoblast-like stem cell and cell-cycle associated genes in in vivo maintained worms. The more rapid growth/development of in vivo juveniles was further evidenced by a switch in cathepsin protease expression profiles, dominated by cathepsin B in in vitro juveniles and then by cathepsin L in in vivo juveniles. Coincident with more rapid growth/development was the marked downregulation of both classical and peptidergic neuronal signalling components in in vivo maintained juveniles, supporting a role for the nervous system in regulating liver fluke growth and development. Differences in the miRNA complements of in vivo and in vitro juveniles identified 31 differentially expressed miRNAs, notably fhe-let-7a-5p , fhe-mir-124-3p and, miRNAs predicted to target Wnt-signalling, supporting a key role for miRNAs in driving the growth/developmental differences in the in vitro and in vivo maintained juvenile liver fluke. Widespread differences in the expression of neuronal genes in juvenile fluke grown in vitro and in vivo expose significant interplay between neuronal signalling and the rate of growth/development, encouraging consideration of neuronal targets in efforts to dysregulate growth/development for parasite control.

scholarly journals In vitro and in vivo trematode models for chemotherapeutic studies

Parasitology ◽  
2009 ◽  
Vol 137 (3) ◽  
pp. 589-603 ◽  
Author(s):  
J. KEISER
Keyword(s):  
Liver Fluke ◽  
Fasciola Hepatica ◽  
State Of The Art ◽  
Parasitic Diseases ◽  
Current State ◽  
Food Borne ◽  
Essential Components ◽  
Discovery Pipeline

SUMMARYSchistosomiasis and food-borne trematodiases are chronic parasitic diseases affecting millions of people mostly in the developing world. Additional drugs should be developed as only few drugs are available for treatment and drug resistance might emerge. In vitro and in vivo whole parasite screens represent essential components of the trematodicidal drug discovery cascade. This review describes the current state-of-the-art of in vitro and in vivo screening systems of the blood fluke Schistosoma mansoni, the liver fluke Fasciola hepatica and the intestinal fluke Echinostoma caproni. Examples of in vitro and in vivo evaluation of compounds for activity are presented. To boost the discovery pipeline for these diseases there is a need to develop validated, robust high-throughput in vitro systems with simple readouts.

A dipeptidylpeptidase secreted by Fasciola hepatica

Parasitology ◽  
1994 ◽  
Vol 109 (1) ◽  
pp. 113-118 ◽  
Author(s):  
C. Carmona ◽  
S. McGonigle ◽  
A. J. Dowd ◽  
A. M. Smith ◽  
S. Coughlan ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Ion Exchange ◽  
Liver Fluke ◽  
Fasciola Hepatica ◽  
Gel Filtration ◽  
Serine Proteinase ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Substrate Preference ◽  
Proteolytic Digestion

SUMMARYA dipeptidylpeptidase (DPP) was isolated from Fasciola hepatica by gel-filtration and ion-exchange chromatography. The exoproteinase is secreted by newly excysted juveniles, immature and mature flukes. The liver fluke DPP is a serine proteinase of molecular weight > 200 kDa and differs from previously characterized mammalian DPPs in its substrate preference and susceptibility to inactivation by inhibitors. The parasite DPP may function in the latter stages of the proteolytic digestion of host macromolecules. In this manner, the enzyme may be important in providing the parasite with dipeptides that could be absorbed through the intestine as nutrient.

scholarly journals RNA interference dynamics in juvenile Fasciola hepatica are altered during in vitro growth and development

2020 ◽  
Author(s):  
Paul McCusker ◽  
Wasim Hussain ◽  
Paul McVeigh ◽  
Erin McCammick ◽  
Nathan G. Clarke ◽  
...  
Keyword(s):  
Rna Interference ◽  
Functional Genomics ◽  
Liver Fluke ◽  
Fasciola Hepatica ◽  
Life Stage ◽  
Life Stages ◽  
Functional Studies ◽  
Rnai Efficiency ◽  
The Impact

AbstractFor over a decade RNA interference (RNAi) has been an important molecular tool for functional genomics studies in parasitic flatworms. Despite this, our understanding of RNAi dynamics in many flatworm parasites, such as the temperate liver fluke (Fasciola hepatica), remains rudimentary. The ability to maintain developing juvenile fluke in vitro provides the opportunity to perform functional studies during development of the key pathogenic life stage. Here, we investigate the RNAi competence of developing juvenile liver fluke. Firstly, all life stages examined possess, and express, core candidate RNAi effectors encouraging the hypothesis that all life stages of F. hepatica are RNAi competent. RNAi effector analyses supported growing evidence that parasitic flatworms have evolved a separate clade of RNAi effectors with unknown function. Secondly, we assessed the impact of growth / development during in vitro culture on RNAi in F. hepatica juveniles and found that during the first week post-excystment liver fluke juveniles exhibit quantitatively lower RNAi mediated transcript knockdown when maintained in growth inducing media. This did not appear to occur in older in vitro juveniles, suggesting that rapidly shifting transcript dynamics over the first week following excystment alters RNAi efficacy after a single 24 hour exposure to double stranded (ds)RNA. Finally, RNAi efficiency was found to be improved through use of a repeated dsRNA exposure methodology that has facilitated silencing of genes in a range of tissues, thereby increasing the utility of RNAi as a functional genomics tool in F. hepatica.

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