Meeting Abstract
Holospora is a genus of bacterial parasites that only grow and divide within one of the two nuclei of their Paramecium caudatum hosts. Our study focuses on Holospora undulata, a species that infects the micronucleus of specific P. caudatum strains. Infection comes at a significant growth-rate cost to the P. caudatum host, and we expect that host defense mechanisms are activated in response to the presence of H. undulata. Currently we are focused on determining what genes are associated with membrane trafficking and what stages of infection the resistant strains of P. caudatum are blocked at. To find the genes that are upregulated at specific time points during infection, we have been staging infections and isolating mRNA through the infection cycle. Preliminary results showed that after 30 minutes of non-resistant P. caudatum infection by H. undulata, approximately 106 genes were upregulated and 28 genes downregulated. Considering 9000 out of 18000 P. caudatum genes have a functional annotation, the small amount of functionally annotated genes from our experiments suggests that the genes that are being up and downregulated during H. undulata infection are Paramecium-specific genes and evolving quickly in response to the presence of H. undulata. From our preliminary results, some genes of interest include a MATE pathogen toxin efflux family protein and the homolog of Paramecium tetraurelia 51A surface antigen protein, both upregulated after 10 minutes of infection. Our research will provide insight into host-pathogen relationships in general, particularly in the Rickettsial family, Holospora’s closest relative and also an intracellular parasite.
