Effect of gravitational deposition on biofilm formation and development

Biofilms ◽  
2008 ◽  
pp. 1-9
Author(s):  
Y. Yang

ABSTRACTAlthough gravitational deposition is generally regarded to be important during biofilm development because it provides a mechanism by which bacteria can come into contact with a surface, this process is usually neglected in most biofilm studies. The purpose of this study was to develop a better understanding of the effect of gravitational deposition by comparing the development of biofilms on the upper and lower surfaces of a capillary glass tube biofilm reactor under various hydrodynamic conditions. Pure cultures ofPseudomonas fluorescensandShewanella oneidensisMR-1 were used for the test. Results demonstrated that gravitational deposition significantly influences biofilm development under slow laminar flow conditions, which may be attributable to the effect of gravity on both attachment and detachment during the initial reversible attachment phase and the later development phase. Additionally, it was shown that hydrodynamic conditions have the potential to reduce the impact of gravitational deposition on biofilm development, and that this became less significant with an increase in flow rate. These results will be useful for comparing biofilm development in different biofilm systems.

Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 653 ◽  
Author(s):  
Sara I. Faria ◽  
Rita Teixeira-Santos ◽  
Maria J. Romeu ◽  
João Morais ◽  
Vitor Vasconcelos ◽  
...  

Understanding the conditions affecting cyanobacterial biofilm development is crucial to develop new antibiofouling strategies and decrease the economic and environmental impact of biofilms in marine settings. In this study, we investigated the relative importance of shear forces and surface hydrophobicity on biofilm development by two coccoid cyanobacteria with different biofilm formation capacities. The strong biofilm-forming Synechocystis salina was used along with the weaker biofilm-forming Cyanobium sp. Biofilms were developed in defined hydrodynamic conditions using glass (a model hydrophilic surface) and a polymeric epoxy coating (a hydrophobic surface) as substrates. Biofilms developed in both surfaces at lower shear conditions contained a higher number of cells and presented higher values for wet weight, thickness, and chlorophyll a content. The impact of hydrodynamics on biofilm development was generally stronger than the impact of surface hydrophobicity, but a combined effect of these two parameters strongly affected biofilm formation for the weaker biofilm-producing organism. The antibiofilm performance of the polymeric coating was confirmed at the hydrodynamic conditions prevailing in ports. Shear forces were shown to have a profound impact on biofilm development in marine settings regardless of the fouling capacity of the existing flora and the hydrophobicity of the surface.


2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Mark Feldman ◽  
Julia Shenderovich ◽  
Eran Lavy ◽  
Michael Friedman ◽  
Doron Steinberg

Thiazolidinediones (TZDs) have been found to act as effective quorum sensing quenchers, capable of preventing biofilm formation. Our previous studies demonstrated a profound antibiofilm effect of the TZD derivative thiazolidinedione-8 (S-8), either in solution or incorporated into a sustained-release membrane (SRM-S-8) under batch conditions. In the present study, we used a constant depth film fermenter model in order to investigate the impact of SRM-S-8 on mixedC. albicans-S. mutansbiofilm development, under flow conditions. We found that essential parameters of cospecies biofilm maintenance and maturation, such as metabolic activity, biofilm thickness, roughness, extracellular polysaccharides production, and morphology of both pathogens, were altered by SRM-S-8 in the flow system. We propose that prolonged and sustained release of S-8 in a flow-through system allows better penetration of the active agent to deeper layers of the mixed biofilm, thereby increasing its activity against both pathogens. In conclusion, the use of a locally applied sustained-release drug delivery system of S-8 can affect the dental polymicrobial biofilm, resulting in clinical improvements and a better patient compliance.


2020 ◽  
Author(s):  
Sara I. Faria ◽  
Rita Teixeira-Santos ◽  
Maria J. Romeu ◽  
João Morais ◽  
Vítor Vasconcelos ◽  
...  

<p>Biofouling is a natural process in marine environments with associated economic and ecological problems. Thus, understanding the conditions that affect cyanobacterial biofilm development is crucial to develop new antibiofouling strategies and decrease the impact of biofilms in the marine environment. In this study, we investigated the relative importance of shear forces and surface hydrophobicity on biofilm development by two coccoid cyanobacteria with different biofilm formation capacities. The strong biofilm-forming <em>Synechocystis salina</em> was used along with the weaker biofilm-forming <em>Cyanobium</em> sp. Biofilms were developed in defined hydrodynamic conditions using glass (a model hydrophilic surface) and a polymeric epoxy coating (a hydrophobic surface) as substrates. Biofilms developed in both surfaces at lower shear conditions contained a higher number of cells and presented higher values for wet weight, thickness, and chlorophyll <em>a</em> content. The impact of hydrodynamics on biofilm development was generally stronger than the impact of surface hydrophobicity, but a combined effect of these two parameters strongly affected biofilm formation for the weaker biofilm-producing organism. The antibiofilm performance of the polymeric coating was confirmed at the hydrodynamic conditions prevailing in ports. Shear forces were shown to have a profound impact on biofilm development in marine settings regardless of the fouling capacity of the existing flora and the hydrophobicity of the surface.</p>


2003 ◽  
Vol 185 (18) ◽  
pp. 5632-5638 ◽  
Author(s):  
Konstantin Agladze ◽  
Debra Jackson ◽  
Tony Romeo

ABSTRACT The complex architecture of bacterial biofilms inevitably raises the question of their design. Microstructure of developing Escherichia coli biofilms was analyzed under static and laminar flow conditions. Cell attachment during early biofilm formation exhibited periodic density patterns that persisted during development. Several models for the origination of biofilm microstructure are considered, including an activator-inhibitor or Turing model.


2016 ◽  
Vol 198 (19) ◽  
pp. 2643-2650 ◽  
Author(s):  
Boo Shan Tseng ◽  
Charlotte D. Majerczyk ◽  
Daniel Passos da Silva ◽  
Josephine R. Chandler ◽  
E. Peter Greenberg ◽  
...  

ABSTRACTMembers of the genusBurkholderiaare known to be adept at biofilm formation, which presumably assists in the survival of these organisms in the environment and the host. Biofilm formation has been linked to quorum sensing (QS) in several bacterial species. In this study, we characterizedBurkholderia thailandensisbiofilm development under flow conditions and sought to determine whether QS contributes to this process.B. thailandensisbiofilm formation exhibited an unusual pattern: the cells formed small aggregates and then proceeded to produce mature biofilms characterized by “dome” structures filled with biofilm matrix material. We showed that this process was dependent on QS.B. thailandensishas three acyl-homoserine lactone (AHL) QS systems (QS-1, QS-2, and QS-3). An AHL-negative strain produced biofilms consisting of cell aggregates but lacking the matrix-filled dome structures. This phenotype was rescued via exogenous addition of the three AHL signals. Of the threeB. thailandensisQS systems, we show that QS-1 is required for proper biofilm development, since abtaR1mutant, which is defective in QS-1 regulation, forms biofilms without these dome structures. Furthermore, our data show that the wild-type biofilm biomass, as well as the material inside the domes, stains with a fucose-binding lectin. ThebtaR1mutant biofilms, however, are negative for fucose staining. This suggests that the QS-1 system regulates the production of a fucose-containing exopolysaccharide in wild-type biofilms. Finally, we present data showing that QS ability during biofilm development produces a biofilm that is resistant to dispersion under stress conditions.IMPORTANCEThe saprophyteBurkholderia thailandensisis a close relative of the pathogenic bacteriumBurkholderia pseudomallei, the causative agent of melioidosis, which is contracted from its environmental reservoir. Since most bacteria in the environment reside in biofilms,B. thailandensisis an ideal model organism for investigating questions inBurkholderiaphysiology. In this study, we characterizedB. thailandensisbiofilm development and sought to determine if quorum sensing (QS) contributes to this process. Our work shows thatB. thailandensisproduces biofilms with unusual dome structures under flow conditions. Our findings suggest that these dome structures are filled with a QS-regulated, fucose-containing exopolysaccharide that may be involved in the resilience ofB. thailandensisbiofilms against changes in the nutritional environment.


2005 ◽  
Vol 187 (23) ◽  
pp. 8114-8126 ◽  
Author(s):  
Christopher J. Southey-Pillig ◽  
David G. Davies ◽  
Karin Sauer

ABSTRACT Phenotypic and genetic evidence supporting the notion of biofilm formation as a developmental process is growing. In the present work, we provide additional support for this hypothesis by identifying the onset of accumulation of biofilm-stage specific proteins during Pseudomonas aeruginosa biofilm maturation and by tracking the abundance of these proteins in planktonic and three biofilm developmental stages. The onset of protein production was found to correlate with the progression of biofilms in developmental stages. Protein identification revealed that proteins with similar function grouped within similar protein abundance patterns. Metabolic and housekeeping proteins were found to group within a pattern separate from virulence, antibiotic resistance, and quorum-sensing-related proteins. The latter were produced in a progressive manner, indicating that attendant features that are characteristic of biofilms such as antibiotic resistance and virulence may be part of the biofilm developmental process. Mutations in genes for selected proteins from several protein production patterns were made, and the impact of these mutations on biofilm development was evaluated. The proteins cytochrome c oxidase, a probable chemotaxis transducer, a two-component response regulator, and MexH were produced only in mature and late-stage biofilms. Mutations in the genes encoding these proteins did not confer defects in growth, initial attachment, early biofilm formation, or twitching motility but were observed to arrest biofilm development at the stage of cell cluster formation we call the maturation-1 stage. The results indicated that expression of theses genes was required for the progression of biofilms into three-dimensional structures on abiotic surfaces and the completion of the biofilm developmental cycle. Reverse transcription-PCR analysis confirmed the detectable change in expression of the respective genes ccoO, PA4101, and PA4208. We propose a possible mechanism for the role of these biofilm-specific proteins in biofilm formation.


2017 ◽  
Vol 83 (17) ◽  
Author(s):  
Miho Kitayama ◽  
Ryota Koga ◽  
Takuya Kasai ◽  
Atsushi Kouzuma ◽  
Kazuya Watanabe

ABSTRACT An electrochemical flow cell equipped with a graphite working electrode (WE) at the bottom was inoculated with Shewanella oneidensis MR-1 expressing an anaerobic fluorescent protein, and biofilm formation on the WE was observed over time during current generation at WE potentials of +0.4 and 0 V (versus standard hydrogen electrodes), under electrolyte-flow conditions. Electrochemical analyses suggested the presence of unique electron-transfer mechanisms in the +0.4-V biofilm. Microscopic analyses revealed that, in contrast to aerobic biofilms, current-generating biofilm (at +0.4 V) was thin and flat (∼10 μm in thickness), and cells were evenly and densely distributed in the biofilm. In contrast, cells were unevenly distributed in biofilm formed at 0 V. In situ fluorescence staining and biofilm recovery experiments showed that the amounts of extracellular polysaccharides (EPSs) in the +0.4-V biofilm were much smaller than those in the aerobic and 0-V biofilms, suggesting that Shewanella cells suppress the production of EPSs at +0.4 V under flow conditions. We suggest that Shewanella cells perceive electrode potentials and modulate the structure and composition of biofilms to efficiently transfer electrons to electrodes. IMPORTANCE A promising application of microbial fuel cells (MFCs) is to save energy in wastewater treatment. Since current is generated in these MFCs by biofilm microbes under horizontal flows of wastewater, it is important to understand the mechanisms for biofilm formation and current generation under water-flow conditions. Although massive work has been done to analyze the molecular mechanisms for current generation by model exoelectrogenic bacteria, such as Shewanella oneidensis, limited information is available regarding the formation of current-generating biofilms over time under water-flow conditions. The present study developed electrochemical flow cells and used them to examine the electrochemical and structural features of current-generating biofilms under water-flow conditions. We show unique features of mature biofilms actively generating current, creating opportunities to search for as-yet-undiscovered current-generating mechanisms in Shewanella biofilms. Furthermore, information provided in the present study is useful for researchers attempting to develop anode architectures suitable for wastewater treatment MFCs.


2020 ◽  
Author(s):  
Lydie Ploux ◽  
Min Jin ◽  
Sophie Hellé ◽  
Cosette Betscha ◽  
Jean-Marc Strub ◽  
...  

<p>L- and D-Cateslytin (CTL) are antimicrobial peptides (AMP) derived from chromogranin A, a protein of the stress response system. Their antimicrobial properties have been thoroughly characterized and already exploited in biomaterials. However, effects on biofilms of yeast and bacteria have never been specifically addressed. We have investigated the impact of both L and D configurations of CTL on the growth of biofilms formed by Candida albicans, Escherichia coli or Staphylococcus aureus microorganisms.</p> <p>The study was conducted in different media and two strategies of treatment were tested, consisting of administrating the peptide either just at the beginning of biofilm development i.e. on just adhering pioneer microbial cells or on a biofilm already allowed to develop for 24h. We also considered whether the peptide was modified in contact with the medium or/and microbial metabolites. Planktonic and sessile populations of microbial cells were analyzed by spectrophotometry, crystal violet staining, MTT and confocal microscopy with staining by Syto9Ò and propidium iodide. Identification of the peptides and their derived fragments was investigated by HPLC and Mass-Spectroscopy.</p> <p>In general, CTL-D exhibited higher antibiofilm performances than CTL-L. In addition, concentrations necessary to inhibit biofilm formation were found to vary from ten to eighty times the MICs determined in planktonic cultures. Nevertheless, the results also demonstrate that sessile microorganisms and biofilms are sensitive to CTL (L and D conformations) differently that planktonic populations. Significant (p-value < 0.01) effects were observed on both sessile and planktonic populations and with both strategies of treatments, but they highly varied with medium, species and CTL configuration. Typically, better antibiofilm effect than common antibiotics was reached in some specific conditions, while enhancement of aggregation or biofilm formation occurred in another medium and for other doses. Nevertheless,</p> <p>Finally, this confirms the quality of CTL peptides as new antimicrobial agents and reveals their anti-biofilm properties. This also specifies the conditions of use necessary to benefit of the highest performances.</p>


2021 ◽  
Author(s):  
Sebastian Munoz ◽  
Benjamin F. Trueman ◽  
Bofu Li ◽  
Graham A. Gagnon

AbstractSodium silicates have been studied for sequestration of iron, coagulation, and corrosion control, but their impact on biofilm formation has not been documented in detail. This study investigated the impact of sodium silicate corrosion control on biomass accumulation in drinking water systems in comparison to orthophosphate, a common corrosion inhibitor. Biofilm growth was measured by determining ATP concentrations, and the bacterial community was characterized using 16S ribosomal RNA (rRNA) sequencing. A pilot-scale study with cast-iron pipe loops, annular reactors (ARs), and polycarbonate coupons demonstrated significantly lower biofilm ATP concentrations in the sodium silicate-treated AR than the orthophosphate-treated AR when the water temperature exceeded 20°C. However, an elevated sodium silicate dose (48 mg L-1 of SiO2) disturbed and dispersed the biofilm formed inside the AR, resulting in elevated effluent ATP concentrations. Two separate experiments confirmed that biomass accumulation was higher in the presence of orthophosphate at high water temperatures (20°C) only. No significant differences were identified in biofilm ATP concentrations at lower water temperatures (below 20°C). Differences in bacterial communities between the orthophosphate- and sodium silicate-treated systems were not statistically significant, even though orthophosphate promoted higher biofilm growth. However, the genera Halomonas and Mycobacterium—which include opportunistic pathogens—were present at greater relative abundances in the orthophosphate-treated system compared to the sodium silicate system.Graphical abstractOrthophosphate promotes more biofilm growth in comparison to sodium silicates at water temperatures above 20°C.Water impact statementSodium silicates have been used in drinking water treatment for decades, both as sequestrants and as corrosion inhibitors. However, their impact on biofilm formation is poorly understood, and this risks drinking water quality. This study aims to further clarify the effects of corrosion inhibitors on biofilm development, including inhibitors that are not phosphate-based.


2008 ◽  
Vol 74 (17) ◽  
pp. 5466-5474 ◽  
Author(s):  
Tae-Jong Kim ◽  
Briana M. Young ◽  
Glenn M. Young

ABSTRACT Yersinia enterocolitica biovar 1B is one of a number of strains pathogenic to humans in the genus Yersinia. It has three different type III secretion systems, Ysc, Ysa, and the flagella. In this study, the effect of flagella on biofilm formation was evaluated. In a panel of 31 mutant Y. enterocolitica strains, we observed that mutations that abolish the structure or rotation of the flagella greatly reduce biofilm formation when the bacteria are grown under static conditions. These results were further evaluated by assessing biofilm formation under continuous culture using a flow cell chamber. The results confirmed the important contribution of flagella to the initiation of biofilm production but indicated that there are differences in the progression of biofilm development between static growth and flow conditions. Our results suggest that flagella play a critical role in biofilm formation in Y. enterocolitica.


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