Parasitology

Biography

Biography: Liang Wu

Abstract

To explore Toxoplasma gondii nucleus coding apicoplast protein ACP synthesis and trafficking in delayed death. The recombinant T. gondii ACP was expressed by prokaryotic expression method, and anti-ACP polyclonal antibody was obtained from rabbit immune. T. gondii “delayed death” was induced by clindamycin, and ACP transcription was determined by Real-time PCR assay. The expression of ACP with transit type and mature type was determined by Western blotting with anti-ACP polyclonal antibody. The mutant expressed ACP fused with GFP tag was constructed by pHX-ACP-GFP. The distribution of ACP in “delayed death” was observed by ACP-GFP fusion protein with Confocal Microscope. T. gondii ACP transcription and t-ACP expression had no significant decrease in the early 4 h of “delayed death”, but there has been a significant decrease in 6 h. The expression of m-ACP had a significant decrease in 4 h which occured earlier than t-ACP expression. The number of brightly dot green fluorescence in ACP-GFP mutant decreased with prolonged time. There was very little brightly dot green fluorescence in ACP-GFP mutant when treated with clindamycin for 6 h. Clindamycin could suppress apicoplast proliferation and induce T. gondii “delayed death”, however it could not directly suppress nucleus coding ACP transcription and expression. T. gondii lacking of apicoplast had a barrier of transit peptide cleavage and t-ACP could not be transformed into m-ACP. The reason for the decrease in ACP expression could be due to excessive t-ACP synthesis in tachyzoites resulting in a negative feedback for the ACP coding gene transcription.