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Biofilm matrix

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


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TL;DR: The potential for biofilm formation by at least three medically important species of zygomycetes is highlighted, including Rhizopus oryzae, Lichtheimia corymbifera, Rhizomucor pusillus and Apophysomyces elegans.
Abstract: Most studies on fungal biofilms have focused on Candida in yeasts and Aspergillus in mycelial fungi. To the authors’ knowledge, biofilm formation by zygomycetes has not been reported previously. In this study, the biofilm-forming capacity of Rhizopus oryzae, Lichtheimia corymbifera, Rhizomucor pusillus and Apophysomyces elegans was evaluated. At appropriate seeding spore densities, Rhp . oryzae (105 c.f.u. ml−1), L. corymbifera (104 c.f.u. ml−1) and Rhm. pusillus (104 c.f.u. ml−1) produced highly intertwined, adherent structures on flat-bottomed polystyrene microtitre plates after 24 h at 37 °C. The adhered fungal hyphae were encased in an extracellular matrix, as confirmed by phase-contrast and confocal microscopy. The thickness of Rhp. oryzae, L. corymbifera and Rhm. pusillus biofilms was 109.67±10.02, 242±23.07 and 197±9.0 µm (mean±sd), respectively. Biochemical characterization of the biofilm matrix indicated the presence of glucosamine, constituting 74.54–82.22 % of its dry weight, N-acetylglucosamine, glucose and proteins. Adherence and biofilm formation were not observed in A. elegans. Although A. elegans spores germinated at all three seeding densities tested (1×107, 1×106 and 1×105 c.f.u. ml−1), no significant difference was observed (P>0.05) between the A 490 of wells inoculated with A. elegans and the cut-off A 490 for biofilm detection. This study highlights the potential for biofilm formation by at least three medically important species of zygomycetes.

74 citations

Journal ArticleDOI
TL;DR: It could be concluded that nanocarriers of about 100 nm and smaller are good candidates to improve the treatment of chronic pulmonary biofilms in CF patients and the confocal microscopy method demonstrated here is a useful tool to assess the penetration of nanomedicines in biofilm clusters.

74 citations

Journal ArticleDOI
TL;DR: This review highlights microscopic approaches to investigate bacterial biofilm assembly, matrix composition, and localization using Pseudomonas aeruginosa as a model organism and describes some outstanding questions and how microscopy might be used to identify the functional aspects of biofilm matrix components.
Abstract: Most microbes can produce surface-associated or suspended aggregates called biofilms, which are encased within a biopolymer-rich matrix. The biofilm matrix provides structural integrity to the aggregates and shields the resident cells against environmental stressors, including antibiotic treatment. Microscopy permits examination of biofilm structure in relation to the spatial localization of important biofilm matrix components. This review highlights microscopic approaches to investigate bacterial biofilm assembly, matrix composition, and localization using Pseudomonas aeruginosa as a model organism. Initial microscopic investigations provided information about the role key matrix components play in elaborating biofilm aggregate structures. Additionally, staining of matrix components using specific labels revealed distinct positioning of matrix components within the aggregates relative to the resident cells. In some cases, it was found that individual matrix components co-localize within aggregates. The methodologies for studying the biofilm matrix are continuing to develop as our studies reveal novel aspects of its composition and function. We additionally describe some outstanding questions and how microscopy might be used to identify the functional aspects of biofilm matrix components.

74 citations

Journal ArticleDOI
TL;DR: Different approaches to combine biofilm-controlling compounds and antibiotics to fight biofilm infections are discussed, as well as the balance between biofilm formation and virulence.
Abstract: Many bacteria grow on surfaces forming biofilms. In this structure, they are well protected and often high dosages of antibiotics cannot clear infectious biofilms. The formation and stabilization of biofilms are mediated by diffusible autoinducers (e.g. N-acyl homoserine lactones, small peptides, furanosyl borate diester). Metabolites interfering with this process have been identified in plants, animals and microbes, and synthetic analogues are known. Additionally, this seems to be not the only way to control biofilms. Enzymes capable of cleaving essential components of the biofilm matrix, e.g. polysaccharides or extracellular DNA, and thus weakening the biofilm architecture have been identified. Bacteria also have mechanisms to dissolve their biofilms and return to planktonic lifestyle. Only a few compounds responsible for the signalling of these processes are known, but they may open a completely novel line of biofilm control. All these approaches lead to the destruction of the biofilm but not the killing of the pathogens. Therefore, a combination of biofilm-destroying compounds and antibiotics to handle biofilm infections is proposed. In this article, different approaches to combine biofilm-controlling compounds and antibiotics to fight biofilm infections are discussed, as well as the balance between biofilm formation and virulence.

74 citations

Journal ArticleDOI
TL;DR: Results suggest that electrical resistance through the biofilm does not restrict long-range electron transfer and cells far from the electrode can respire across metabolically inactive cells, taking advantage of their extracellular infrastructure produced during the initial biofilm formation.
Abstract: In this study, we quantified electron transfer rates, depth profiles of electron donor, and biofilm structure of Geobacter sulfurreducens biofilms using an electrochemical-nuclear magnetic resonance microimaging biofilm reactor. Our goal was to determine whether electron donor limitations existed in electron transfer processes of electrode-respiring G. sulfurreducens biofilms. Cells near the top of the biofilms consumed acetate and were metabolically active; however, acetate concentration decreased to below detection within the top 100 microns of the biofilms. Additionally, porosity in the biofilms fell below 10% near the electrode surface, exacerbating exclusion of acetate from the lower regions. The dense biofilm matrix in the acetate-depleted zone acted as an electrical conduit passing electrons generated at the top of the biofilm to the electrode. To verify the distribution of cell metabolic activity, we used uranium as a redox-active probe for localizing electron transfer activity and X-ray absorption spectroscopy to determine the uranium oxidation state. Cells near the top reduced UVI more actively than the cells near the base. High-resolution transmission electron microscopy images showed intact, healthy cells near the top and plasmolyzed cells near the base. Contrary to models proposed in the literature, which hypothesize that cells nearest the electrode surface are the most metabolically active because of a lower electron transfer resistance, our results suggest that electrical resistance through the biofilm does not restrict long-range electron transfer. Cells far from the electrode can respire across metabolically inactive cells, taking advantage of their extracellular infrastructure produced during the initial biofilm formation.

74 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20224
2021138
2020189
2019157
2018121
2017113