Elevated levels of the second messenger molecule cyclic di-GMP alter the balance of extracellular matrix components, and the phenotypes of lapA and lapF mutants under these conditions are indicative of direct interactions taking place

between large secreted proteins and exopolysaccharides. Our data suggest the existence of a mechanism by which bacteria would sense alterations in the composition of the extracellular Metabolism inhibitor matrix, leading to changes in expression of the different elements. (c) 2013 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.”
“The Klebsiella oxytoca lipoprotein PulS might function as either or both a pilot and a docking factor in the outer membrane targeting and assembly of the

Type II secretion system secretin PulD. In the piloting model, PulS binds to PulD monomers and targets them to the outer membrane via the lipoprotein sorting pathway components LolA and LolB. In this model, PulS also protects the PulD monomers from proteolysis during transit U0126 supplier through the periplasm In the docking model, PulS is targeted alone to the outer membrane, where it acts as a receptor for PulD monomers, allowing them to accumulate and assemble specifically in this membrane. PulS was shown to dissociate from and/or re-associate freely with PulD multimers in zwitterionic detergent, making it difficult to determine whether PulS remains associated with Pull) dodecamers in the outer membrane by co-purification. However, PulD protomers in the dodecamer were shown to be stable in the absence of PulS, indicating that PulS is only required to protect the protease-susceptible monomer. DegP was identified as one of the proteases that could contribute to PulD degradation in the absence of PulS. Studies on the in vitro assembly and targeting of PulD into Escherichia coli membrane vesicles demonstrated its strong preference to insert into the inner membrane, as is the case in vivo in the absence of PulS. However, PulD could be targeted to outer membrane fragments in vitro if they were preloaded with PulS, indicating the technical feasibility of the docking model. We conclude that both modes

of action might contribute to efficient outer membrane targeting of PulD in vivo, Ulixertinib cell line although the piloting function is likely to predominate. (c) 2013 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.”
“Acinetobacter baumannii is an important nosocomial pathogen responsible for colonization and infection of critically ill patients. Its virulence attributes together with the condition of the host determine the pathogenicity of A. baumannii. These virulence factors may be delivered to host cells by membrane vesicles. The aim of this study was to characterize the formation and morphology of membrane vesicles (MVs) from A. baumannii ATCC19606(T) using cryo-electron microscopy. Cryo-electron microscopy imaging of A.