Molecular Parasitology

A broad range of molecular techniques have been employed by the Parasitology research group in recent years including in situ hybridisation, microsatellite analysis, real-time PCR, DNA microarray and phylogenetic and diagnostic analysis employing a range of targeted gene sequences. Recent studies have used such approaches to search for genetic markers to identify different sea lice populations, both wild and farm, and to look at the level of interaction between them.

Recent molecular work includes a BBSRC-funded project investigating the triggering of moulting and metamorphosis in copepodid larvae of the salmon louse in collaboration with the University of Liverpool. This project has employed DNA microarray technology and a range of allied molecular techniques to successfully demonstrate the regulation of key genes involved in the process of parasite transformation following host attachment. This is the first time that this has been achieved for an aquatic parasitic arthropod and that moulting and metamorphosis have been studied at this level for any copepod species, free-living or parasitic. This research has established a time-course for key gene regulation events and allowed identification of critical components of the parasite response to the salmon host, thereby contributing substantially to knowledge of the biology of this important pathogen. Key genes identified for the first time by this research may provide targets for the future development of highly parasite-specific medicines and vaccines.Considerable progress has been made in the areas of myxosporean ecology and host-parasite interactions through the use of in situ hybridization for the localization and specific detection of infecting and developing stages coupled with the use of targeted PCR for the purposes of parasite identification and phylogeny.

Selected References

  1. Holzer, A.S., Wootten, R. & Sommerville, C. (2007) The secondary structure of the unusually long 18S ribosomal RNA of the myxozoan Sphaerospora truttae and structural evolutionary trends in the Myxozoa. International Journal for Parasitology, 37 (11), 1173-1296.
  2. Holzer, A.S., Sommerville, C. & Wootten, R. (2006) Molecular studies on the seasonal occurrence and development of five myxozoans in farmed Salmo trutta L. Parasitology, 132, 193-205.
  3. Holzer, A.S., Sommerville, C. & Wootten, R. (2005) Molecular identity, phylogeny and life-cycle of Chloromyxum schurovi Shul’man & Ieshko 2005. Parasitology Research, 99 (1), 90-96.
  4. Dixon, B. A., Shinn, A.P. & Sommerville, C. (2004) Genetic characterisation of populations of the ectoparasitic caligid, Lepeophtheirus salmonis (Krøyer, 1837) using randomly amplified polymorphic DNA (RAPDs). Aquaculture Research, 35, 730-741.
  5. Holzer, A.S., Sommerville, C. & Wootten, R. (2004) Molecular relationshipsand phylogeny in a community of myxosporeans and actinosporeans based on their 18S rDNA sequences. International Journal for Parasitology, 34 (10), 1099-1111.
  6. Holzer, A.S., Sommerville, C. and Wootten, R. (2003) Tracing the route of Spheraerospora truttae from the entry locus to the target organ of the host, Salmo salar L., using an optomized and specific in situ hybrdization technique. Journal of Fish Diseases, 26, 647-655.
  7. Kral’ova-Hromadova, I., Scholz, T, Shinn, A.P., Cunningham, C.O., Wootten, R., Hanzelova, V. & Sommerville, C. (2003) A molecular study of Eubothrium (Cestoda: Pseudophyllidea) using ITS rDNA sequences. Parasitology Research, 89 (6), 473-479.
  8. Kral’ová-Hromadova, I., Tietz, D.T., Shinn, A.P. & Špakulová, M. (2003) Pomphorhynchus laevis (Acanthocephala: Palaeacanthocephala): ITS rDNA intraspecific variation. Systematic Parasitology, 56 (2), 141-145.
  9. Bell, A.S., Sommerville, C. & Tellervo Valtonen, E. (2001) A molecular phylogeny of the genus Ichthyocotylurus (Digenea, Strigeidae). International Journal of Parasitology, 31(8), 833-842.
  10. Shinn, A.P., Banks, B.A., Bron, J.E. & Sommerville, C. (2000) Utility of 18S rDNA and ITS sequences as population markers for Lepeophtheirus salmonis (Krøyer, 1837) (Copepoda: Caligidae) parasitising Atlantic salmon (Salmo salar) in Scotland. Contributions to Zoology, 69 (1/2), 89-98.
  11. Bell, A.S., Yokoyama, H., Aoki, T., Takahashi, M. & Maruyama, K. (1999) Single and nested polymerase chain reaction assays for the detection of Microsporidium seriolae (Microspora), the causative agent of ‘Beco’ disease in yellowtail Seriola quinqueradiata. Diseases of Aquatic Organisms , 37, 127-134.