Requirements for Borrelia burgdorferi plasmid maintenance.

Borrelia burgdorferi has multiple linear and circular plasmids that are faithfully replicated and partitioned as the bacterium grows and divides. The low copy number of these replicons implies that active partitioning contributes to plasmid stability. Analyzing the requirements for plasmid replication and partition in B.

Autophagy-mediated reentry of Francisella tularensis into the endocytic compartment after cytoplasmic replication.

Intracellular bacterial pathogens evade the bactericidal functions of mammalian cells by physical escape from their phagosome and replication into the cytoplasm or through the modulation of phagosome maturation and biogenesis of a membrane-bound replicative organelle. Here, we detail in murine primary macrophages the intracellular life cycle of Francisella tularensis, a highly infectious bacterium that survives and replicates within mammalian cells. After transient interactions with the endocytic pathway, bacteria escaped from their phagosome by 1 h after infection and underwent replication in the cytoplasm from 4 to 20 h after infection.

Sigma(s)-dependent regulation of yehZYXW, which encodes a putative osmoprotectant ABC transporter of Escherichia coli.

The Escherichia coli yehZYXW operon encodes a putative osmoprotectant uptake system of the ABC transporter family. yehZ is identical to osmF, an osmotically inducible gene identified previously. Construction and analysis of a yehZ-lacZ transcriptional fusion demonstrated that yehZ is inducible not only by osmolarity, but also upon entry into stationary phase.

Interactions between the 2.4 and 4.2 regions of sigmaS, the stress-specific sigma factor of Escherichia coli, and the -10 and -35 promoter elements.

The sigmas subunit of Escherichia coli RNA polymerase holoenzyme (EsigmaS) is a key factor of gene expression upon entry into stationary phase and in stressful conditions. The selectivity of promoter recognition by EsigmaS and the housekeeping Esigma70 is as yet not clearly understood. We used a genetic approach to investigate the interaction of sigmaS with its target promoters.