RNA Analysis of Bd0422 and Bd2350 Motility Genes in Bdellovibrio bacteriovorus
Authors:Hyeong-Jin Kim, Nick Thomas
Mentor:Eileen Spain, Professor of Chemistry, Occidental College
Bdellovibrio bacteriovorus is a gram-negative delta-proteobacterium. The two main stages in the bacteria’s life cycle are the host-dependent and the host-independent phase. Host-dependent Bdellovirbrio bacteriovorus functions as a predatory bacterium that attacks other gram-negative bacterium. The host-dependent morphology uses its flagella to prey on other bacterium. The counterpart is the host-independent form of Bdellovirbrio bacteriovorus. When the bacterium occupies this stage it is able to survive purely on the resources in the surrounding environment. When B. bacteriovorus is placed on a filter paper it self-organizes into a biofilm in which the host-dependent cells stay in proximity to the inoculation site and the host-independent migrate out. Our research investigated two genes (Bd0422 and Bd2350) and their expression levels in host-dependent verse host-independent by isolating both stages via the biofilm. Both Bd0422 and Bd2350 code for ubiquinone genes, which are involved in creating ATP in the mitochondria of the cell. The hypothesis for this experiment was Bd0422 and Bd2350 would have higher expression in the host-dependent stage because the host dependant stage requires more energy in order to hunt the E. coli prey. The ubiquinone genes are linked to ATP and therefore are hypothesized to be linked to motility, because motility requires energy in the cell. Through multiple electrophoresis gels with controls, our research supported this hypothesis and showed that both Bd0422 and Bd2350 were more highly expressed in the host-dependent stage of B. bacteriovorus, and that both genes had lower expression levels in the host-independent stage. This research was accomplished using RNA isolation techniques, RT-PCR, and gel electrophoresis analysis.