Characterization of the Erwinia chrysanthemi osmoprotectant transporter gene ousA

International audienceGrowth of Erwinia chrysanthemi in media of elevated osmolarity can be achieved by the uptake and accumulation of various osmoprotectants. This study deals with the cloning and sequencing of the ousA gene-encoded osmoprotectant uptake system A from E. chrysanthemi 3937. OusA belongs to the superfamily of solute ion cotransporters. This osmotically inducible system allows the uptake of glycine betaine, proline, ectoine, and pipecolic acid and presents strong similarities in nucleotide sequence and protein function with the proline/betaine porter of Escherichia coli encoded by proP. The control of ousA expression is clearly different from that of proP. It is induced by osmotic strength and repressed by osmoprotectants. Its expression in E. coli is controlled by H-NS and is rpoS dependent in the exponential phase but unaffected by the stationary phase

Corynephages: Infections of the Infectors

Corynebacterium diphtheriae is the etiological agent of diphtheria; an acute toxin-mediated infection of the upper respiratory tract and skin. The toxin gene is encoded on a temperate bacteriophage, which during lysogeny is capable of toxin production. In this chapter, we will summarise current knowledge regarding corynephage, focusing on the lifecycle and biology of the toxin-carrying corynephages that are known to convert pathogenic corynebacteria, and discuss the insights recent genome corynebacterial sequencing has given us