Biological insights sheared from sheep parasite genome
27 Aug 2013
The genome of the barber’s pole worm, Haemonchus contortus, a common parasite that infects ruminants and is threatening the viability of the sheep industry, is revealed in two papers in the open access journal Genome Biology this week. These studies will boost fundamental research on nematodes and assist/underpin the development of new vaccines and drugs to curb the ill health, production and economic losses caused by these unwelcome worms.
H. contortus causes serious disease problems, including anemia, and can cause death in infected sheep, goats and some other ruminants. Animals become infected when they graze on contaminated pasture, and the parasite causes losses estimated at billions of dollars per annum. At present, H. contortus is controlled by anthelmintic drugs, but resistance is becoming an increasing problem, so the hunt is on for new intervention targets and diagnostics.
H. contortus is closely related to a number of parasites that infect humans (such as hookworms),
and the sheep/H. contortus model provides a useful system for the validation of drugs and vaccines for a wide range of related and socioeconomically important parasitic nematodes.
Two teams, each based at a variety of research institutes, have sequenced the genomes of Australian and UK strains of the worm. The studies identify hundreds of new, potential drug targets. These include molecules involved in enzymatic chokepoints, reactions that uniquely consume or produce metabolites, presumed essential for the parasite's survival. Disrupt the enzyme, the theory goes, and the worm should die either through starvation or a build-up of toxic products.
James A. Cotton and colleagues highlight five particular chokepoint enzymes, presumed to be parasite-specific, of which two are already being researched as drug targets – one for Mycobacterium tuberculosis, the bacterium that causes tuberculosis, the other for Brugia malayi, the worm that causes elephantiasis. Robin B. Gasser and colleagues also highlight more than 200 genes encoding proteins involved in RNA interference, a naturally-occurring cellular mechanism that could be assessed by drug-developers to switch off vital parasitic genes.
Both teams were able to pinpoint drug targets by looking for genes enriched in the different stages of the parasite’s complex 3 week life cycle. Eggs, excreted in host feces, hatch within a day or so then proceed through various larval stages, before they switch from the free-living to a parasitic mode when they are consumed by unwitting ruminants. Both groups highlight the potential importance of genes encoding peptidases – enzymes thought to help break down host tissue and digest blood – in the worm’s parasitic phase. It is hoped that these and other biologically-relevant enzymes prove useful candidates as vaccines.
- ENDS -
Head of Communication, BioMed Central
Tel: +44 20 3192 2737
Mobile: +44 7825 287 546
Notes to Editors
1. The genome and transcriptome of Haemonchus contortus, a key model parasite for drug and vaccine discovery
Roz Laing, Taisei Kikuchi, Axel Martinelli, Isheng J Tsai, Robin N Beech, Elizabeth Redman, Nancy Holroyd, David J Bartley, Helen Beasley, Collette Britton, David Curran, Eileen Devaney, Aude Gilabert, Martin Hunt, Frank Jackson, Stephanie Johnston, Ivan Kryukov, Keyu Li, Alison A Morrison, Adam J Reid, Neil Sargison, Gary Saunders, James D Wasmuth, Adrian Wolstenholme, Matthew Berriman, John S Gilleard and James A Cotton
Genome Biology 2013, 14:R88 doi:10.1186/gb-2013-14-8-r88
The genome and developmental transcriptome of the strongylid nematode Haemonchus contortus
Erich M Schwarz, Pasi K Korhonen, Bronwyn E Campbell, Neil D Young, Aaron R Jex, Abdul Jabbar, Ross S Hall, Alinda Mondal, Adina C Howe, Jason Pell, Andreas Hofmann, Peter R Boag, Xingquan Zhu, T Ryan Gregory, Alex Loukas, Brian A Williams, Igor Antoshechkin, C Titus Brown, Paul W Sternberg and Robin B Gasser
Genome Biology 2013, 14:R89 doi:10.1186/gb-2013-14-8-r89
Please name the journal in any story you write. If you are writing for the web, please link to the article. All articles are available free of charge, according to BioMed Central’s open access policy.
2. Genome Biology serves the biological research community as an international forum for the dissemination, discussion and critical review of information about all areas of biology informed by genomic research. Key objectives are to provide a guide to the rapidly developing resources and technology in genomics and its impact on biological research, to publish large datasets and extensive results that are not readily accommodated in traditional journals, and to help establish new standards and nomenclature for post-genomic biology.
3. BioMed Central (http://www.biomedcentral.com/) is an STM (Science, Technology and Medicine) publisher which has pioneered the open access publishing model. All peer-reviewed research articles published by BioMed Central are made immediately and freely accessible online, and are licensed to allow redistribution and reuse. BioMed Central is part of Springer Science+Business Media, a leading global publisher in the STM sector. @BioMedCentral