Biofilm matrix

About: Biofilm matrix is a research topic. Over the lifetime, 1589 publications have been published within this topic receiving 110140 citations.

Advanced techniques for in situ analysis of the biofilm matrix (structure, composition, dynamics) by means of laser scanning microscopy

Abstract: The extracellular constituents in bioaggregates and biofilms can be imaged four dimensionally by using laser scanning microscopy. In this protocol we provide guidance on how to examine the various extracellular compartments in between microbial cells and communities associated with interfaces. The current options for fluorescence staining of matrix compounds and extracellular microhabitats are presented. Furthermore, practical aspects are discussed and useful notes are added. The chapter ends with a brief introduction to other approaches for EPS analysis and an outlook for future needs.

The Role of Biofilms in the Uptake and Transformation of Dissolved Organic Matter

Abstract: Publisher Summary This chapter focuses on the sorption of Dissolved Organic Matter (DOM) onto and the transformations of DOM in biofilms Biofilms are abundant in a multitude of aquatic environments in which they cover all kinds of inorganic and organic solid surfaces They exhibit different morphologies depending on the environmental conditions In a flow system with turbulent flow, a laminar boundary layer is formed between the turbulent flow and the biofilm The gellike biofilm matrix may be quite unimportant in impeding diffusion in certain circumstances, because of the detailed consequences of the diffusion law in special geometries Gradients of nutrients and oxygen in biofilms additionally promote high diversity, which may ultimately result in functional differences of the bacterial community in biofilms, when compared with free-floating bacteria Biofilms enhance bacteria-DOM interactions by several means Their spatial and chemical heterogeneity provides additional sorption sites for DOM compared with clean surfaces Their loose architecture with interstitial voids and channels increases diffusivity and to some extent allows convective flow within biofilm structures Because bacteria metabolize organic matter sorbed to the biofilm, a diffusion flux from the free water to the biofilm is maintained Because of the high area of solid surfaces covered with biofilms, these biofilms dominate the heterotrophic metabolism in many aquatic ecosystems By the differential use of specific DOM fractions, biofilm bacteria influence the biogeochemical composition of DOM in these ecosystems Thus, biofilms can control biogeochemical fluxes of DOM and are important sinks of organic matter

Bdellovibrio bacteriovorus HD100, a predator of Gram-negative bacteria, benefits energetically from Staphylococcus aureus biofilms without predation

Abstract: Bdellovibrio bacteriovorus HD100 is a predatory bacterium which lives by invading the periplasm of Gram-negative bacteria and consuming them from within. Although B. bacteriovorus HD100 attacks only Gram-negative bacterial strains, our work here shows attack-phase predatory cells also benefit from interacting with Gram-positive biofilms. Using Staphylococcus aureus biofilms, we show this predator degrades the biofilm matrix, obtains nutrients and uses these to produce and secrete proteolytic enzymes to continue this process. When exposed to S. aureus biofilms, the transcriptome of B. bacteriovorus HD100 was analogous to that seen when present intraperiplasmically, suggesting it is responding similarly as when in a prey. Moreover, two of the induced proteases (Bd2269 and Bd2692) were purified and their activities against S. aureus biofilms verified. In addition, B. bacteriovorus HD100 gained several clear benefits from its interactions with S. aureus biofilms, including increased ATP pools and improved downstream predatory activities when provided prey.

Correlation between biofilm production, antibiotic susceptibility and exopolysaccharide composition in Burkholderia pseudomallei bpsI, ppk, and rpoS mutant strains.

Abstract: Burkholderia pseudomallei is the cause of melioidosis, a fatal tropical infectious disease, which has been reported to have a high rate of recurrence, even when an intensive dose of antibiotics is used. Biofilm formation is believed to be one of the possible causes of relapse because of its ability to increase drug resistance. EPS in biofilms have been reported to be related to the limitation of antibiotic penetration in B. pseudomallei. However, the mechanisms by which biofilms restrict the diffusion of antibiotics remain unclear. The present study presents a correlation between exopolysaccharide production in biofilm matrix and antibiotic resistance in B. pseudomallei using bpsI, ppk, and rpoS mutant strains. CLSM revealed a reduction in exopolysaccharide production and disabled micro-colony formation in B. pseudomallei mutants, which paralleled the antibiotic resistance. Different ratios of carbohydrate contents in the exopolysaccharides of the mutants were detected, although they have the same components, including glucose, galactose, mannose, and rhamnose, with the exception being that no detectable rhamnose peak was observed in the bpsI mutant. These results indicate that the correlation between these phenomena in the B. pseudomallei biofilm at least results from the exopolysaccharide, which may be under the regulation of bpsI, ppk, or rpoS genes.