Brucella abortus is responsible for bovine brucellosis. It is a Rhizobiale, part of the alpha-proteobacteria. Several beta-barrels of the outer membrane are covalently attached to the peptidoglycan through their N-terminus, and perturbation of this attachment leads to blebbing of the outer membrane. New peptidoglycan, outer membrane proteins and lipopolysaccharide (LPS) are inserted at the new pole, the one generated by cell division. Localization of the Lpt proteins involved in LPS export from the inner to the outer membrane suggest that polar insertion is directed by inner membrane complex of the Lpt system. Incorporation of KDO-azide and mannose-azide allows the monitoring of new LPS insertion, suggesting that homeostasis of the outer membrane involves LPS replacement in defined medium.