Molecular Analysis Of Surface Antigen 5 (Sag5) From Coccidia Parasite, Eimeria tenella
ABSTRACT Coccidiosis is an intestinal disease caused by intracellular parasites belonging to several species of Eimeria．The pathogenic characteristics of coccidiosis are fast propagation and difficulty to eliminate. It mainly infects chickens and had caused high mortality and reduced in the producti...
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| Format: | Thesis |
| Language: | English |
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| Summary: | ABSTRACT Coccidiosis is an intestinal disease caused by intracellular parasites belonging to several species of Eimeria．The pathogenic characteristics of coccidiosis are fast propagation and difficulty to eliminate. It mainly infects chickens and had caused high mortality and reduced in the production of chicken. At present, this disease is controlled by prophylactic drugs and live vaccines. The extensive use of these drugs has resulted in the development of drug resistance in Eimeria spp,. Even though live vaccines are effective but the use of this vaccine is complex and expensive. Surface antigens of Eimeria have been suggested to play important roles in parasites pathogenicity and immunogenicity. The most endogenous antigens could be from the stage of merozoites, which can induce host immune response. Studies have showed that the surface antigen of merozoite are glycosylphosphatidylinositol (GPI)-linked surface proteins, which have an N-terminal hydrophobic signal peptide，a C-terminal hydrophobic GPI signal-anchor peptide and an extracellular domain organized around six cysteine residues. The role of these surface antigens in host cell invasion and immunity evasion remain elusive. However, the main objective of this study is to carry out the initial crystallization trials for E. tenella surface antigen 5 (SAG5). In this study cDNA of SAG5 was amplified using PCR and was subsequently cloned into pET100/D-TOPO vector. The sequence of the gene was verified by sequencing. Positive plasmids were then transformed into Escherichia coli Rosetta gami 2 (DE3) for over expression. The over expressed protein (~27 kDa) was successfully purified using affinity and anion exchange chromatography. The presence of the purified protein was further verified by western blot and mass spectrometer to confirm the western blot results. Subsequently, initial crystallization trials were carried out using standard sitting-drop vapor diffusion method. However, no crystals have been observed. |
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