Variation of Physiochemical Properties and Cell Association Activity of Membrane Vesicles with Growth Phase in Pseudomonas aeruginosa

Abstract

Pseudomonas aeruginosa and other Gram-negative bacteria release membrane vesicles (MVs) from their surfaces, and MVs have an ability to interact with bacterial cells. Although it has been known that many bacteria have mechanisms that control their phenotypes with the transition from exponential phase to stationary phase, changes of properties in released MVs have been poorly understood. Here, we demonstrate that MVs released by P. aeruginosa during the exponential and stationary phases possess different physiochemical properties. MVs purified from the stationary phase had higher buoyant densities than did those purified from the exponential phase. Surface charge, characterized by zeta potential, of MVs tended to be more negative as the growth shifted to the stationary phase, although the charges of PAO1 cells were not altered. Pseudomonas quinolone signal (PQS), one of the regulators related to MV production in P. aeruginosa, was lower in MVs purified from the exponential phase than in those from the stationary phase. MVs from the stationary phase more strongly associated with P. aeruginosa cells than did those from the exponential phase. Our findings suggest that properties of MVs are altered to readily interact with bacterial cells along with the growth transition in P. aeruginosa.

Production of Outer Membrane Vesicles and Outer Membrane Tubes by Francisella novicida

“…Thus, the content of the F. novicida vesicles changes with growth phase. A similar dynamic protein content has been reported for OMV isolated from P. aeruginosa (43).…”

“…The F. novicida OMV characterized by Pierson et al were isolated from bacteria after 44 h of growth (32), a time in late stationary phase when many bacteria are likely dying and releasing contents due to cell lysis. The protein composition and other properties of OMV may change with growth phase (43), and vesicles produced by dying bacteria are expected to be different from vesicles produced during bacterial growth. Therefore, we examined F. novicida strain U112 for the production of OMV at earlier stages of growth.…”

Influence of O Polysaccharides on Biofilm Development and Outer Membrane Vesicle Biogenesis in Pseudomonas aeruginosa PAO1

“…OMVs have been implicated in many extracellular activities, including the secretion of degradative enzymes (7), the release of quorum-sensing molecules and virulence factors (8)(9)(10), and the transfer of genetic information (7,(11)(12)(13). In the opportunistic Gram-negative pathogen Pseudomonas aeruginosa, OMVs are associated with both planktonic and surface-associated biofilm communities, and their compositions and properties vary based on their mode of growth (14,15). OMVs have also been identified as an important component of the extracellular matrix of P. aeruginosa biofilms and contribute a large portion of the protein content to this extracellular niche (15,16).…”

A Great Leap forward in Microbial Ecology

“…Another characteristic of the PQS molecule is that it could induce the production of outer membrane vesicles that contain active proteins and perform diverse biological processes (103,153). Several mechanisms have been proposed for the biogenesis of the outer membrane vesicles (87,152).…”