scholarly journals Characterization of a secreted cystatin of the parasitic nematode Haemonchus contortus and its immune-modulatory effect on goat monocytes

2017 ◽  
Vol 10 (1) ◽  
Author(s):  
Yujian Wang ◽  
Lingyan Wu ◽  
Xinchao Liu ◽  
Shuai Wang ◽  
Muhammad Ehsan ◽  
...  
Keyword(s):  
Haemonchus Contortus ◽  
Parasitic Nematode

Molecular characterization of a family of metalloendopeptidases from the intestinal brush border of Haemonchus contortus

Parasitology ◽  
2006 ◽  
Vol 133 (3) ◽  
pp. 357-368 ◽  
Author(s):  
G. F. J. NEWLANDS ◽  
P. J. SKUCE ◽  
A. J. NISBET ◽  
D. L. REDMOND ◽  
S. K. SMITH ◽  
...  
Keyword(s):  
Haemonchus Contortus ◽  
Proteomic Analysis ◽  
Parasitic Nematode ◽  
Integral Membrane Protein ◽  
Cleavage Sites ◽  
Molecular Architecture ◽  
Intestinal Brush Border ◽  
Typical Type ◽  
Ph Range

Substantial protection against the economically important parasitic nematode Haemonchus contortus has been achieved by immunizing sheep with a glycoprotein fraction isolated from the intestinal membranes of the worm (H-gal-GP). Previous studies showed that one of the major components of H-gal-GP is a family of at least 4 zinc metalloendopeptidases, designated MEPs 1–4. This paper describes aspects of the molecular architecture of this protease family, including the proteomic analysis of the MEP fraction of the H-gal-GP complex. These enzymes belong to the M13 zinc metalloendopeptidase family (EC 3.4.24.11), also known as neutral endopeptidases or neprilysins. The sequences of MEPs 1 and 3 suggested a typical Type II integral membrane protein structure, whilst MEPs 2 and 4 had putative cleavable signal peptides, typical of secreted proteins. Proteomic analysis of H-gal-GP indicated that the extracellular domain of all 4 MEPs had been cleaved close to the transmembrane region/signal peptide with additional cleavage sites mid-way along the polypeptide. MEP3 was present as a homo-dimer in H-gal-GP, whereas MEP1 or MEP2 formed hetero-dimers with MEP4. It was found that expression of MEP3 was confined to developing 4th-stage larvae and to adult worms, the stages of Haemonchus which feed on blood. MEP-like activity was detected in the H-gal-GP complex over a broad pH range (5–9). Since all 4 MEPs must share a similar microenvironment in the complex, this suggests that each might have a different substrate specificity.

Phenotypic characterization of Haemonchus contortus: a study of isolates from Sweden and Kenya in experimentally infected sheep

Parasitology ◽  
2005 ◽  
Vol 132 (3) ◽  
pp. 403-409 ◽  
Author(s):  
K. TROELL ◽  
C. TINGSTEDT ◽  
J. HÖGLUND
Keyword(s):  
Haemonchus Contortus ◽  
Parasitic Nematode ◽  
Geographical Origin ◽  
Climatic Conditions ◽  
Phenotypic Characterization ◽  
Phenotypic Traits ◽  
Patent Period ◽  
Third Stage ◽  
Pre Treatment

The effects of cold storage of infective third-stage larvae (L3) of different isolates of the parasitic nematode Haemonchus contortus were studied with respect to infectivity, pre-patent period and propensity for larval arrestment. Two complementary experiments were conducted with 2 groups of lambs, each animal being inoculated with 2000 L3 of either Swedish or Kenyan origin. In a first experiment, L3s were cold treated at 5 °C for 9 months prior to infection, whereas in a second experiment larvae were newly hatched. Individual faecal egg counts (FECs), and worm burdens were determined for each experiment. The results showed that the greatest differences were associated with the pre-treatment of larvae. The pre-patent period and the FECs differed significantly between the experiments but not between the isolates used in each experiment. However, the extent of hypobiosis was significantly different between the two isolates when fresh larvae were used (36% Kenyan isolate and 70% Swedish). The storage of H. contortus at 5 °C had no apparent effect on the infectivity of L3s, as high establishment ranging from 43 to 74% were observed, irrespective of isolates used. This study showed that H. contortus exhibited similar phenotypic traits regardless of geographical origin. Thus, there was limited evidence for adaptations to temperate climatic conditions.

A novel member of the ligand-gated chloride channel gene family from Haemonchus contortus

Parasitology ◽  
2007 ◽  
Vol 135 (4) ◽  
pp. 539-545 ◽  
Author(s):  
S. G. FORRESTER ◽  
S. Z. SIDDIQUI
Keyword(s):  
Gene Family ◽  
Haemonchus Contortus ◽  
Chloride Channels ◽  
Parasitic Nematode ◽  
Developmental Stages ◽  
Parasitic Nematodes ◽  
Terminal Ligand ◽  
Isolation And Characterization ◽  
Early Developmental

SUMMARYLigand-gated chloride channels (LGCCs) are key components of the nervous system of parasitic nematodes and important targets for anthelmintics. Here, we describe the isolation and characterization of a novel member of the LGCC gene family (HcLGCC1) from the parasitic nematode Haemonchus contortus. Sequence analysis revealed that the channel subunit encoded by HcLGCC1 is anion selective and a member of a group of channels characterized as having two Cys-loops in the N-terminal ligand-binding domain†. Although the overall function of HcLGCC1 is presently unknown, the gene may play a key role in the early developmental stages of the parasite. Further investigations into the function of LGCCs, such as HcLGCC1, in parasitic nematodes should have implications for the discovery of new anthelmintic targets.

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