Biofilm dispersion in Pseudomonas aeruginosa

Abstract

In recent decades, many researchers have written numerous articles about microbial biofilms. Biofilm is a complex community of microorganisms and an example of bacterial group behavior. Biofilm is usually considered a sessile mode of life derived from the attached growth of microbes to surfaces, and most biofilms are embedded in self-produced extracellular matrix composed of extracellular polymeric substances (EPSs), such as polysaccharides, extracellular DNAs (eDNA), and proteins. Dispersal, a mode of biofilm detachment indicates active mechanisms that cause individual cells to separate from the biofilm and return to planktonic life. Since biofilm cells are cemented and surrounded by EPSs, dispersal is not simple to do and many researchers are now paying more attention to this active detachment process. Unlike other modes of biofilm detachment such as erosion or sloughing, which are generally considered passive processes, dispersal occurs as a result of complex spatial differentiation and molecular events in biofilm cells in response to various environmental cues, and there are many biological reasons that force bacterial cells to disperse from the biofilms. In this review, we mainly focus on the spatial differentiation of biofilm that is a prerequisite for dispersal, as well as environmental cues and molecular events related to the biofilm dispersal. More specifically, we discuss the dispersal-related phenomena and mechanisms observed in Pseudomonas aeruginosa, an important opportunistic human pathogen and representative model organism for biofilm study.

Mechanisms and Regulation of Extracellular DNA Release and Its Biological Roles in Microbial Communities

“…This might account for the observed differences in eDNA production between cells in planktonic cultures and in biofilms. In this sense, although several mechanisms were described for the eDNA release in planktonic cultures, some of them were not found or were different in biofilms (Sauer et al, 2002; Greiner et al, 2005; Allesen-Holm et al, 2006; Kim and Lee, 2016). …”

The Social Life of Aeromonas through Biofilm and Quorum Sensing Systems

“…Very few data on Aeromonas biofilm detachment and dispersion are available, and most knowledge relies on data from P. aeruginosa biofilm models. Dispersion is triggered by exogenous factors such as nutrient availability and toxic compounds, and by internal regulatory systems including quorum sensing systems (Kim and Lee, 2016). To enhance its dispersion, it is suspected that aeromonads degrade some compounds of their own extracellular polymeric matrix or other bacteria.…”

Plasticity of Candida albicans Biofilms

“…Both are motile when planktonic but become nonmotile during adherence, and as noted, the flagellar motor can play a direct and early role in the initial adhesion event (119-122). As P. aeruginosa biofilms grow, the cells remain nonmotile, but at maturity, mushroom-like pillars separated by water channels form within the biofilms, which contain motile cells that exit in the process of dispersal (81,118,123,124). Not only the size of the biofilm but also multicellular morphogenesis is regulated by quorum sensing (125)(126)(127).…”