Exopolysaccharides of the Biofilm Matrix: A Complex Biophysical World

Lembré, Pierre; Lorentz, C.; Martino, Patrick Di

doi:10.5772/51213

Cited by 70 publications

(63 citation statements)

References 79 publications

(76 reference statements)

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“…Biofilms also contain bacterially derived alginates that, in contrast to OligoG CF-5/20, lack G-blocks and have a considerably higher molecular mass (51). Anionic EPS components, such as carboxyl groups, interact strongly with multivalent cations, such as Ca 2ϩ , resulting in robust biofilms (52).…”

Section: Discussionmentioning

confidence: 99%

A Low-Molecular-Weight Alginate Oligosaccharide Disrupts Pseudomonal Microcolony Formation and Enhances Antibiotic Effectiveness

Pritchard

Powell

Jack

et al. 2017

Antimicrob Agents Chemother

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In chronic respiratory disease, the formation of dense, 3-dimensional "microcolonies" by Pseudomonas aeruginosa within the airway plays an important role in contributing to resistance to treatment. An in vitro biofilm model of pseudomonal microcolony formation using artificial-sputum (AS) medium was established to study the effects of low-molecular-weight alginate oligomers (OligoG CF-5/20) on pseudomonal growth, microcolony formation, and the efficacy of colistin. The studies employed clinical cystic fibrosis (CF) isolates (n ϭ 3) and reference nonmucoid and mucoid multidrug-resistant (MDR) CF isolates (n ϭ 7). Bacterial growth and biofilm development and disruption were studied using cell viability assays and image analysis with scanning electron and confocal laser scanning microscopy. Pseudomonal growth in AS medium was associated with increased ATP production (P Ͻ 0.05) and the formation (at 48 h) of discrete (Ͼ10-m) microcolonies. In conventional growth medium, colistin retained an ability to inhibit growth of planktonic bacteria, although the MIC was increased (0.1 to 0.4 g/ml) in AS medium compared to Mueller-Hinton (MH) medium. In contrast, in an established-biofilm model in AS medium, the efficacy of colistin was decreased. OligoG CF-5/20 (Ն2%) treatment, however, induced dose-dependent biofilm disruption (P Ͻ 0.05) and led to colistin retaining its antimicrobial activity (P Ͻ 0.05). While circular dichroism indicated that OligoG CF-5/20 did not change the orientation of the alginate carboxyl groups, mass spectrometry demonstrated that the oligomers induced dose-dependent (Ͼ0.2%; P Ͻ 0.05) reductions in pseudomonal quorum-sensing signaling. These findings reinforce the potential clinical significance of microcolony formation in the CF lung and highlight a novel approach to treat MDR pseudomonal infections.

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Section: Discussionmentioning

confidence: 99%

A Low-Molecular-Weight Alginate Oligosaccharide Disrupts Pseudomonal Microcolony Formation and Enhances Antibiotic Effectiveness

Pritchard

Powell

Jack

et al. 2017

Antimicrob Agents Chemother

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“…Indeed, these different components signify the integrity of biofilms and make them resilient towards a variety of environmental factor. When environmental factors are considered, these microbial biofilms can be found on inundated conditions and submerged platforms in natural and industrial environment [25]. Despite the fact, that the biofilms are mainly composed of extra polymeric matrices, the importance of DNA cannot be denied as it is essential for the establishment of the biofilm structure [26].…”

Section: What Are Biofilms Composed Of?mentioning

confidence: 99%

Biofilms: Microbial Cities of Scientific Significance

Ramachandran¹

2014

JMEN

108

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“…Unfolding and subsequent stiffening of the protein chains located inside EPS resulted in increment of stiffness within the biofilm network. Even though there exist other polymeric materials within the EPS matrix that shows shear-thinning behavior for small time scales, only the shear-stiffening protein chains have been considered in the present study as a first approximation[40]. Since the bacteria located within the biofilm network acts as a rigid body, with increasing bacteria loading, effective stiffness of the biofilm network increases.…”

Section: Resultsmentioning

confidence: 99%

Modeling of Mesoscale Variability in Biofilm Shear Behavior

2016

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Formation of bacterial colonies as biofilm on the surface/interface of various objects has the potential to impact not only human health and disease but also energy and environmental considerations. Biofilms can be regarded as soft materials, and comprehension of their shear response to external forces is a key element to the fundamental understanding. A mesoscale model has been presented in this article based on digitization of a biofilm microstructure. Its response under externally applied shear load is analyzed. Strain stiffening type behavior is readily observed under high strain loads due to the unfolding of chains within soft polymeric substrate. Sustained shear loading of the biofilm network results in strain localization along the diagonal direction. Rupture of the soft polymeric matrix can potentially reduce the intercellular interaction between the bacterial cells. Evolution of stiffness within the biofilm network under shear reveals two regimes: a) initial increase in stiffness due to strain stiffening of polymer matrix, and b) eventual reduction in stiffness because of tear in polymeric substrate.

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Exopolysaccharides of the Biofilm Matrix: A Complex Biophysical World

Cited by 70 publications

References 79 publications

A Low-Molecular-Weight Alginate Oligosaccharide Disrupts Pseudomonal Microcolony Formation and Enhances Antibiotic Effectiveness

A Low-Molecular-Weight Alginate Oligosaccharide Disrupts Pseudomonal Microcolony Formation and Enhances Antibiotic Effectiveness

Biofilms: Microbial Cities of Scientific Significance

Modeling of Mesoscale Variability in Biofilm Shear Behavior

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