Project description:Japanese flounder (Paralichthys olivaceus) is an economic important aquaculture fish that was susceptible to Vibrio anguillarum. To fully deciphered the molecular mechanisms underlying flounder host defense against V. anguillarum infection, we perform the micro-transcriptome analysis of founder spleen with and without V. anguillarum infection at 3 time points.
Project description:Here, we define the VanT-QS regulon and explore the diversity and trajectory of traits under QS regulation in the fish pathogen Vibrio anguillarum through comparative transcriptomics of two wildtype strains and their corresponding mutants artificially locked in QS-on (ΔvanO) or QS-off (ΔvanT) states. We reveal that populations of one strain primarily employ a QS-off response, while the other strain mainly maneuvers within the QS-on spectrum. Further examination of our V. anguillarum collection revealed that ~15 % of the strains were QS-negative and measurements of a total of 9 QS-positive strains suggested diverse QS responses, which underlines an extensive diversity of QS delegations. We show that QS control a plethora of genes involved in processes such as central metabolism, biofilm, competence, T6SS and virulence in V. anguillarum. Interestingly, the low QS response strain had an enlarged QS regulon compared to the high QS response strain, suggesting a potential trade-off between engagement in QS and output of the commitment. Moreover, the combination of present and previous virulence trials coupled with QS response measurements indicate that the QS state is an important driver of virulence toward fish larvae in V. anguillarum. We propose that infections by mixed-strain communities spanning diverse QS strategies might utilize the animal host more efficiently. Furthermore, we emphasize the importance of applying whole-cell spike-in normalization to study gene expression of cell populations with differential total RNA content per cell.
Project description:The gram-negative bacterium Vibrio (Listonella) anguillarum is the causative agent of vibriosis, a bacterial disease affecting aquacultural industry across the globe. The full mechanism of V. anguillarum pathogenesis is not completely understood, but many virulence determinants have been identified. The current study aimed to obtain molecular insights into the proteome response of the bacterium to several conditions mimicking vibriosis. Our data shed light on the adaptability of V. anguillarum to oxidative stress, iron limitations and the complement system, and offer potential virulence determinants associated in particular with septicemia over the course of vibriosis.
