Project description:Bdellovibrio bacteriovorus is a Gram-negative bacterium that is a pathogen of other Gram-negative bacteria, including many bacteria which are pathogens of humans, animals and plants. As such Bdellovibrio has potential as a biocontrol agent, or living antibiotic. B. bacteriovorus HD100 has a large genome and it is not yet known which of it encodes the molecular machinery and genetic control of predatory processes. We have tried to fill this knowledge-gap using mixtures of predator and prey mRNAs to monitor changes in Bdellovibrio gene expression at a timepoint of early-stage prey infection and prey killing in comparison to control cultures of predator and prey alone and also in comparison to Bdellovibrio growing axenically (in a prey-or host independent âHIâ manner) on artificial media containing peptone and tryptone. From this we have highlighted genes of the early predatosome with predicted roles in prey killing and digestion and have gained insights into possible regulatory mechanisms as Bdellovibrio enter and establish within the prey bdelloplast. Approximately seven percent of all Bdellovibrio genes were significantly up-regulated at 30 minutes of infection- but not in HI growth- implicating the role of these genes in prey digestion. Five percent were down-regulated significantly, implicating their role in free-swimming, attack-phase physiology. This study gives the first post- genomic insight into the predatory process and reveals some of the important genes that Bdellovibrio expresses inside the prey bacterium during the initial attack. Keywords: Transcriptional analysis 3 replicates of attack phase cells and 3 replicates of 30 minutes post-infection cells were analysed on individual arrays. Replicate 3 was normalized separately.
Project description:Bdellovibrio bacteriovorus is a Gram-negative bacterium that is a pathogen of other Gram-negative bacteria, including many bacteria which are pathogens of humans, animals and plants. As such Bdellovibrio has potential as a biocontrol agent, or living antibiotic. B. bacteriovorus HD100 has a large genome and it is not yet known which of it encodes the molecular machinery and genetic control of predatory processes. We have tried to fill this knowledge-gap using mixtures of predator and prey mRNAs to monitor changes in Bdellovibrio gene expression at a timepoint of early-stage prey infection and prey killing in comparison to control cultures of predator and prey alone and also in comparison to Bdellovibrio growing axenically (in a prey-or host independent “HI” manner) on artificial media containing peptone and tryptone. From this we have highlighted genes of the early predatosome with predicted roles in prey killing and digestion and have gained insights into possible regulatory mechanisms as Bdellovibrio enter and establish within the prey bdelloplast. Approximately seven percent of all Bdellovibrio genes were significantly up-regulated at 30 minutes of infection- but not in HI growth- implicating the role of these genes in prey digestion. Five percent were down-regulated significantly, implicating their role in free-swimming, attack-phase physiology. This study gives the first post- genomic insight into the predatory process and reveals some of the important genes that Bdellovibrio expresses inside the prey bacterium during the initial attack. Keywords: Transcriptional analysis
Project description:Bdellovibrio is a Gram-negative bacterium that preys upon other Gram-negative bacteria, including many pathogens, and as such has potential as a biocontrol agent. Little is known of the molecular and genetic control of Bdellovibrioâ??s attack upon its prey and of the nature of the HI phenotype. Here, we apply microarray technology to monitor changes of gene expression during the initial stages of prey infection to determine which predatory genes are important in this stage and to gain insight into possible regulatory mechanisms controlling the predation process. Comparison to gene expression during HI growth reveals a â??predatosomeâ?? of genes specifically upregulated during predation and implicates some of those important in HI growth. 3 replicates of attack phase cells and 3 replicates of Host-Independent grown cells were analysed on individual arrays.
Project description:Attack-Phase Bdellovibrio bacteriovorus Responses to Extracellular Nutrients Are Analogous to Those Seen During Late Intraperiplasmic Growth
Project description:Bdellovibrio bacteriovorus 109J is a predatory bacterium which lives by predating on other Gram-negative bacteria to obtain the nutrients it needs for replication and survival. Here, we evaluated the effects a bacterial signaling molecule called diffusible signaling factor (DSF) have on B. bacteriovorus 109J transcriptomics.