A transcriptomic analysis of the phylum Nematoda.

Hospital for Sick Children, 555 University Avenue, Departments of Biochemistry and Medical Genetics and Microbiology, University of Toronto, Toronto, Ontario M5G 1X8, Canada.
Nature Genetics (Impact Factor: 35.21). 01/2005; 36(12):1259-67. DOI: 10.1038/ng1472
Source: PubMed

ABSTRACT The phylum Nematoda occupies a huge range of ecological niches, from free-living microbivores to human parasites. We analyzed the genomic biology of the phylum using 265,494 expressed-sequence tag sequences, corresponding to 93,645 putative genes, from 30 species, including 28 parasites. From 35% to 70% of each species' genes had significant similarity to proteins from the model nematode Caenorhabditis elegans. More than half of the putative genes were unique to the phylum, and 23% were unique to the species from which they were derived. We have not yet come close to exhausting the genomic diversity of the phylum. We identified more than 2,600 different known protein domains, some of which had differential abundances between major taxonomic groups of nematodes. We also defined 4,228 nematode-specific protein families from nematode-restricted genes: this class of genes probably underpins species- and higher-level taxonomic disparity. Nematode-specific families are particularly interesting as drug and vaccine targets.

  • [Show abstract] [Hide abstract]
    ABSTRACT: Toxocarosis is of major canine health and socioeconomic importance worldwide. Although many studies have given insights into toxocarosis, to date, there has been limited exploration of the molecular biology, biochemistry, genetics, epidemiology and ecology of Toxocara species as well as parasite-host interactions using '-omic' technologies. The present article gives a background on Toxocara species and toxocarosis, describes molecular tools for specific identification and genetic analysis, and provides a prospective view of the benefits that advanced molecular technologies will have towards better understanding the parasites and disease. Tackling key biological questions employing a 'systems biology' approach should lead to new and improved strategies for the treatment, diagnosis and control of toxocarosis.
    Veterinary Parasitology 12/2012; · 2.38 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Background Teladorsagia circumcincta (order Strongylida) is an economically important parasitic nematode of small ruminants (including sheep and goats) in temperate climatic regions of the world. Improved insights into the molecular biology of this parasite could underpin alternative methods required to control this and related parasites, in order to circumvent major problems associated with anthelmintic resistance. The aims of the present study were to define the transcriptome of the adult stage of T. circumcincta and to infer the main pathways linked to molecules known to be expressed in this nematode. Since sheep develop acquired immunity against T. circumcincta, there is some potential for the development of a vaccine against this parasite. Hence, we infer excretory/secretory molecules for T. circumcincta as possible immunogens and vaccine candidates. Results A total of 407,357 ESTs were assembled yielding 39,852 putative gene sequences. Conceptual translation predicted 24,013 proteins, which were then subjected to detailed annotation which included pathway mapping of predicted proteins (including 112 excreted/secreted [ES] and 226 transmembrane peptides), domain analysis and GO annotation was carried out using InterProScan along with BLAST2GO. Further analysis was carried out for secretory signal peptides using SignalP and non-classical sec pathway using SecretomeP tools. For ES proteins, key pathways, including Fc epsilon RI, T cell receptor, and chemokine signalling as well as leukocyte transendothelial migration were inferred to be linked to immune responses, along with other pathways related to neurodegenerative diseases and infectious diseases, which warrant detailed future studies. KAAS could identify new and updated pathways like phagosome and protein processing in endoplasmic reticulum. Domain analysis for the assembled dataset revealed families of serine, cysteine and proteinase inhibitors which might represent targets for parasite intervention. InterProScan could identify GO terms pertaining to the extracellular region. Some of the important domain families identified included the SCP-like extracellular proteins which belong to the pathogenesis-related proteins (PRPs) superfamily along with C-type lectin, saposin-like proteins. The 'extracellular region' that corresponds to allergen V5/Tpx-1 related, considered important in parasite-host interactions, was also identified. Six cysteine motif (SXC1) proteins, transthyretin proteins, C-type lectins, activation-associated secreted proteins (ASPs), which could represent potential candidates for developing novel anthelmintics or vaccines were few other important findings. Of these, SXC1, protein kinase domain-containing protein, trypsin family protein, trypsin-like protease family member (TRY-1), putative major allergen and putative lipid binding protein were identified which have not been reported in the published T. circumcincta proteomics analysis. Detailed analysis of 6,058 raw EST sequences from dbEST revealed 315 putatively secreted proteins. Amongst them, C-type single domain activation associated secreted protein ASP3 precursor, activation-associated secreted proteins (ASP-like protein), cathepsin B-like cysteine protease, cathepsin L cysteine protease, cysteine protease, TransThyretin-Related and Venom-Allergen-like proteins were the key findings. Conclusions We have annotated a large dataset ESTs of T. circumcincta and undertaken detailed comparative bioinformatics analyses. The results provide a comprehensive insight into the molecular biology of this parasite and disease manifestation which provides potential focal point for future research. We identified a number of pathways responsible for immune response. This type of large-scale computational scanning could be coupled with proteomic and metabolomic studies of this parasite leading to novel therapeutic intervention and disease control strategies. We have also successfully affirmed the use of bioinformatics tools, for the study of ESTs, which could now serve as a benchmark for the development of new computational EST analysis pipelines.
    BMC Genomics 13(7). · 4.40 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Toxocara canis is an important gastrointestinal nematode of dogs and also a causative agent of visceral larva migrans in humans. Arginine kinase (AK) gene is one of the important biomolecule of phosphagen kinase of T. canis which is emerging as an exciting novel diagnostic target in toxocarosis. The present study was carried out to clone and characterize AK gene of T. canis for future utilization as a diagnostic molecule. Total RNA was extracted from intact adult worms and reverse transcription was done with oligo dT primers to obtain complementary DNA (cDNA). Polymerase chain reaction (PCR) was carried out using cDNA as template with specific primers which amplified a product of 1,202 bp. The amplicon was cloned into pDrive cloning vector and clone was confirmed by colony PCR and restriction endonuclease analysis. Sequence analysis of the gene showed 99.8 and 77.9 % homology with the published AK gene of T. canis (EF015466.1) and Ascaris suum respectively. Structural analysis shown that the mature AK protein consist of 400 amino acids with a molecular wt of 45360.73 Da. Further expression studies are required for producing the recombinant protein for its evaluation in the diagnosis of T. canis infection in humans as well as in adult dogs.
    Journal of parasitic diseases

Full-text (2 Sources)

Available from
May 21, 2014