RpoE1, an extracytoplasmic function sigma factor, is a repressor of the flagellar system in Brucella melitensis.

The genome of Brucella melitensis contains genes coding for the sigma factors RpoD, RpoN, RpoH1, RpoH2, RpoE1 and RpoE2. Previously published data show that B. melitensis is flagellated and that an rpoE1 mutant overexpresses the flagellar protein FlgE.

An RpoH-like heat shock sigma factor is involved in stress response and virulence in Brucella melitensis 16M.

B. melitensis 16M genome analysis revealed the presence of six putative sigma factor-encoding genes: rpoD, rpoH1, rpoH2, rpoE1, rpoE2, and rpoN. We mutated all these genes except rpoD.

Role of Neisseria meningitidis luxS in cell-to-cell signaling and bacteremic infection.

Numerous pathogenic bacteria contain luxS, which is required for autoinducer-2 production. Here, we demonstrate that Neisseria meningitidis contains a functional copy of luxS that is necessary for full meningococcal virulence; strains with a luxS deletion are defective for bacteremia, a prerequisite of meningococcal pathogenesis.