Abstract:
The protozoan parasite Theileria parva is the causative agent
of cattle theileriosis, a disease with a destructive impact on
the agricultural economy through mortality and morbidity
of affected cattle. In cattle, T. parva infection results in varied
disease syndromes depending on the parasite host of origin;
cattle-derived T. parva causes East Coast fever while buffaloderived
parasites cause Corridor disease. The differences in
the resulting disease caused by T. parva infection have raised
an interest to understand the proteins involved in the disease
manifestations. Consequently, a transcriptome study comparing
the cattle and buffalo-derived T. parva isolates was undertaken;
differentially expressed genes were detected of which 74%
(867) were hypothetical proteins (HPs). Since HPs could play a
vital role in the pathogenicity and host-parasite interaction, the
primary aim of the study was to identify biological roles of these
proteins. A combination of in silico analysis tools was employed
to annotate HPs according to sequence descriptions, confirmed by sequence homology in comparison with closely related
species and conserved domains. Initial screening for sequence
descriptions (SDs) based on sequence similarity search using
Blast2GO retrieved results for 392 HPs. Comparison of this
output to other databases (KEGG and KOBAS) detected
consensus SDs for 229 HPs, of which 109 were further
confirmed by inferring homology to related species. Sequence
homology analysis also resulted in designation of SDs to 74 HPs
from the remaining 163 without consensus SDs from database
analyses. For HPs which did not meet the criteria employed in
sequence homology analysis (209), conserved domain analysis
facilitated assigning of SDs for 114 HPs. Overall, 297 (76%) HPs
were successfully allocated SDs. Finally, the results from this
study have showed that output from automated sequence
similarity databases is not always reliable in assigning SDs for
specific species, making confirmation using other approaches
necessary.
Description:
Poster presented at the University of Pretoria, Faculty of Veterinary Science Faculty Day, August 25, 2016, Pretoria, South Africa.
