scholarly journals Setup and Validation of Flow Cell Systems for Biofouling Simulation in Industrial Settings

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Joana S. Teodósio ◽  
Manuel Simões ◽  
Manuel A. Alves ◽  
Luís F. Melo ◽  
Filipe J. Mergulhão
Keyword(s):  
Dilution Rate ◽  
Biofilm Formation ◽  
Average Velocity ◽  
Cell Concentration ◽  
Flow Simulation ◽  
Flow Cell ◽  
Planktonic Cell ◽  
Time Analysis ◽  
Cell Systems ◽  
Average Wall Shear Stress

A biofouling simulation system consisting of a flow cell and a recirculation tank was used. The fluid circulates at a flow rate of 350 L⋅ h−1in a semicircular flow cell with hydraulic diameter of 18.3 mm, corresponding to an average velocity of 0.275 m⋅ s−1. Using computational fluid dynamics for flow simulation, an average wall shear stress of 0.4 Pa was predicted. The validity of the numerical simulations was visually confirmed by inorganic deposit formation (using kaolin particles) and also by direct observation of pathlines of tracer PVC particles using streak photography. Furthermore, the validity of chemostat assumptions was verified by residence time analysis. The system was used to assess the influence of the dilution rate on biofilm formation byEscherichia coliJM109(DE3). Two dilution rates of 0.013 and 0.0043 h−1were tested and the results show that the planktonic cell concentration is increased at the lower dilution rate and that no significant changes were detected on the amount of biofilm formed in both conditions.

scholarly journals Altering the Ratio of Phenazines in Pseudomonas chlororaphis (aureofaciens) Strain 30-84: Effects on Biofilm Formation and Pathogen Inhibition

2008 ◽  
Vol 190 (8) ◽  
pp. 2759-2766 ◽  
Author(s):  
V. S. R. K. Maddula ◽  
E. A. Pierson ◽  
L. S. Pierson
Keyword(s):  
Fungal Pathogen ◽  
Biofilm Formation ◽  
Flow Cell ◽  
Gaeumannomyces Graminis ◽  
Pseudomonas Chlororaphis ◽  
Wild Type ◽  
Initial Attachment ◽  
Pathogen Inhibition ◽  
Biofilm Development ◽  
Derivatives Of

ABSTRACT Pseudomonas chlororaphis strain 30-84 is a plant-beneficial bacterium that is able to control take-all disease of wheat caused by the fungal pathogen Gaeumannomyces graminis var. tritici. The production of phenazines (PZs) by strain 30-84 is the primary mechanism of pathogen inhibition and contributes to the persistence of strain 30-84 in the rhizosphere. PZ production is regulated in part by the PhzR/PhzI quorum-sensing (QS) system. Previous flow cell analyses demonstrated that QS and PZs are involved in biofilm formation in P. chlororaphis (V. S. R. K. Maddula, Z. Zhang, E. A. Pierson, and L. S. Pierson III, Microb. Ecol. 52:289-301, 2006). P. chlororaphis produces mainly two PZs, phenazine-1-carboxylic acid (PCA) and 2-hydroxy-PCA (2-OH-PCA). In the present study, we examined the effect of altering the ratio of PZs produced by P. chlororaphis on biofilm formation and pathogen inhibition. As part of this study, we generated derivatives of strain 30-84 that produced only PCA or overproduced 2-OH-PCA. Using flow cell assays, we found that these PZ-altered derivatives of strain 30-84 differed from the wild type in initial attachment, mature biofilm architecture, and dispersal from biofilms. For example, increased 2-OH-PCA production promoted initial attachment and altered the three-dimensional structure of the mature biofilm relative to the wild type. Additionally, both alterations promoted thicker biofilm development and lowered dispersal rates compared to the wild type. The PZ-altered derivatives of strain 30-84 also differed in their ability to inhibit the fungal pathogen G. graminis var. tritici. Loss of 2-OH-PCA resulted in a significant reduction in the inhibition of G. graminis var. tritici. Our findings suggest that alterations in the ratios of antibiotic secondary metabolites synthesized by an organism may have complex and wide-ranging effects on its biology.

scholarly journals Synergistic Interaction between Candida albicans and Commensal Oral Streptococci in a NovelIn VitroMucosal Model

2011 ◽  
Vol 80 (2) ◽  
pp. 620-632 ◽  
Author(s):  
Patricia I. Diaz ◽  
Zhihong Xie ◽  
Takanori Sobue ◽  
Angela Thompson ◽  
Basak Biyikoglu ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Gastrointestinal Tract ◽  
Oral Mucosa ◽  
Biofilm Formation ◽  
Salivary Flow ◽  
Flow Cell ◽  
Synergistic Interaction ◽  
Esophageal Mucosa ◽  
Oral Streptococci ◽  
Content Type

ABSTRACTCandida albicansis a commensal colonizer of the gastrointestinal tract of humans, where it coexists with highly diverse bacterial communities. It is not clear whether this interaction limits or promotes the potential ofC. albicansto become an opportunistic pathogen. Here we investigate the interaction betweenC. albicansand three species of streptococci from the viridans group, which are ubiquitous and abundant oral commensal bacteria. The ability ofC. albicansto form biofilms withStreptococcus oralis,Streptococcus sanguinis, orStreptococcus gordoniiwas investigated using flow cell devices that allow abiotic biofilm formation under salivary flow. In addition, we designed a novel flow cell system that allows mucosal biofilm formation under conditions that mimic the environment in the oral and esophageal mucosae. It was observed thatC. albicansand streptococci formed a synergistic partnership whereC. albicanspromoted the ability of streptococci to form biofilms on abiotic surfaces or on the surface of an oral mucosa analogue. The increased ability of streptococci to form biofilms in the presence ofC. albicanscould not be explained by a growth-stimulatory effect since the streptococci were unaffected in their growth in planktonic coculture withC. albicans. Conversely, the presence of streptococci increased the ability ofC. albicansto invade organotypic models of the oral and esophageal mucosae under conditions of salivary flow. Moreover, characterization of mucosal invasion by the biofilm microorganisms suggested that the esophageal mucosa is more permissive to invasion than the oral mucosa. In summary,C. albicansand commensal oral streptococci display a synergistic interaction with implications for the pathogenic potential ofC. albicansin the upper gastrointestinal tract.

Exogenous fungal quorum sensing molecules inhibit planktonic cell growth and modulate filamentation and biofilm formation in the Sporothrix schenckii complex

Biofouling ◽  
2020 ◽  
Vol 36 (8) ◽  
pp. 909-921
Author(s):  
Raimunda Sâmia Nogueira Brilhante ◽  
Vandbergue Santos Pereira ◽  
Augusto Feynman Dias Nobre ◽  
Jonathas Sales de Oliveira ◽  
Mirele Rodrigues Fernandes ◽  
...  
Keyword(s):  
Cell Growth ◽  
Quorum Sensing ◽  
Biofilm Formation ◽  
Sporothrix Schenckii ◽  
Planktonic Cell

Use of flow cell reactors to quantify biofilm formation kinetics

1992 ◽  
Vol 6 (3) ◽  
pp. 193-198 ◽  
Author(s):  
Ching-Tsan Huang ◽  
Steven W. Peretti ◽  
James D. Bryers
Keyword(s):  
Biofilm Formation ◽  
Flow Cell ◽  
Formation Kinetics

Finding the comfort zone: Online-monitoring of electroactive bacteria colonising electrode surfaces with different chemical properties

2020 ◽  
Author(s):  
Hanna Frühauf ◽  
Markus Stöckl ◽  
Dirk Holtmann
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Confocal Laser Scanning Microscopy ◽  
Electrode Surface ◽  
Biofilm Formation ◽  
Laser Scanning ◽  
Electrochemical Impedance ◽  
Flow Cell ◽  
Laser Scanning Microscopy ◽  
Confocal Laser

<p>Mechanisms of electron transfer vary greatly within the diverse group of electroactive microorganisms and so does the need to attach to the electrode surface, e.g. by forming a biofilm.</p> <p>Electrochemical impedance spectroscopy (EIS) and confocal laser scanning microscopy (CLSM) are well established methods to monitor cell attachment to an electrode surface and have therefore been combined in a flow cell as a screening system. The flow cell, equipped with a transparent indium tin oxide working electrode (ITO WE), allows monitoring of attachment processes in real time with minimal needs for additional biofilm preparation. In preliminary experiments the flow cell was successfully used as microbial fuel cell (MFC) with a potential of +0.4 V vs. Ag/AgCl using <em>Shewanella oneidensis</em> as electroactive model organism. [1]</p> <p>Commonly, graphite-based electrode materials are used in bioelectrochemical systems due to their low costs and high conductivity. However, the hydrophobic and negatively charged surface is not yet optimal for microbial attachment. There are numerous attempts on electrode surface engineering in order to overcome this problem. In the majority of studies the biofilm analysis and evaluation of the attachment takes place at the end of the experiment, neglecting the impacts of the chemical surface properties and initial electrode conditioning during the very beginning of biofilm formation.</p> <p>To investigate initial attachment and biofilm formation in real-time, the transparent ITO-electrode is coated with polyelectrolytes differing in hydrophobicity and polarity to evaluate their effects on the initial surface colonisation by different electroactive microorganisms. Combining CLSM and EIS, both, surface coverage and electrochemical interaction of electrode-associated bacteria can be assessed.</p> <p>With this we aim to understand and ease initial steps of biofilm formation to improve efficiency of bioelectrochemical applications, e.g. with regards to start-up time.</p> <p> </p> <p>[1] Stöckl, M., Schlegel, C., Sydow, A., Holtmann, D., Ulber, R., & Mangold, K. M. (2016). Membrane separated flow cell for parallelized electrochemical impedance spectroscopy and confocal laser scanning microscopy to characterize electro-active microorganisms. <em>Electrochimica Acta</em>, 220, 444-452.</p>

scholarly journals Cell Autoaggregation, Biofilm Formation, and Plant Attachment in a Sinorhizobium meliloti lpsB Mutant

2018 ◽  
Vol 31 (10) ◽  
pp. 1075-1082 ◽  
Author(s):  
Fernando Sorroche ◽  
Pablo Bogino ◽  
Daniela M. Russo ◽  
Angeles Zorreguieta ◽  
Fiorela Nievas ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Sinorhizobium Meliloti ◽  
Planktonic Cell ◽  
Confocal Laser ◽  
Bacterial Surface ◽  
Abiotic Surfaces ◽  
Defective Mutant ◽  
Mutant Strains ◽  
Adhesive Interactions ◽  
Biofilm Development

Bacterial surface molecules are crucial for the establishment of a successful rhizobia-legume symbiosis, and, in most bacteria, are also critical for adherence properties, surface colonization, and as a barrier for defense. Rhizobial mutants defective in the production of exopolysaccharides (EPSs), lipopolysaccharides (LPSs), or capsular polysaccharides are usually affected in symbiosis with their plant hosts. In the present study, we evaluated the role of the combined effects of LPS and EPS II in cell-to-cell and cell-to-surface interactions in Sinorhizobium meliloti by studying planktonic cell autoaggregation, biofilm formation, and symbiosis with the host plant Medicago sativa. The lpsB mutant, which has a defective core portion of LPS, exhibited a reduction in biofilm formation on abiotic surfaces as well as altered biofilm architecture compared with the wild-type Rm8530 strain. Atomic force microscopy and confocal laser microscopy revealed an increase in polar cell-to-cell interactions in the lpsB mutant, which might account for the biofilm deficiency. However, a certain level of biofilm development was observed in the lpsB strain compared with the EPS II-defective mutant strains. Autoaggregation experiments carried out with LPS and EPS mutant strains showed that both polysaccharides have an impact on the cell-to-cell adhesive interactions of planktonic bacteria. Although the lpsB mutation and the loss of EPS II production strongly stimulated early attachment to alfalfa roots, the number of nodules induced in M. sativa was not increased. Taken together, this work demonstrates that S. meliloti interactions with biotic and abiotic surfaces depend on the interplay between LPS and EPS II.

scholarly journals MorA Defines a New Class of Regulators Affecting Flagellar Development and Biofilm Formation in Diverse Pseudomonas Species

2004 ◽  
Vol 186 (21) ◽  
pp. 7221-7228 ◽  
Author(s):  
Weng-Keong Choy ◽  
Lian Zhou ◽  
Chris Kiu-Choong Syn ◽  
Lian-Hui Zhang ◽  
Sanjay Swarup
Keyword(s):  
Biofilm Formation ◽  
Planktonic Cell ◽  
Developmentally Regulated ◽  
Ecological Fitness ◽  
Bacterial Flagella ◽  
New Class ◽  
Coordinated Expression ◽  
Stationary Transition ◽  
Flagellar Biogenesis ◽  
Mutant Cells

ABSTRACT Assembly of bacterial flagella is developmentally important during both planktonic cell growth and biofilm formation. Flagellar biogenesis is complex, requiring coordinated expression of over 40 genes, and normally commences during the log-to-stationary transition phase. We describe here a novel membrane-localized regulator, MorA, that controls the timing of flagellar development and affects motility, chemotaxis, and biofilm formation in Pseudomonas putida. MorA is conserved among diverse Pseudomonas species, and homologues are present in all Pseudomonas genomes sequenced thus far. In P. putida, the absence of MorA derepresses flagellar development, which leads to constitutive formation of flagella in the mutant cells in all growth phases. In Pseudomonas aeruginosa, the absence of MorA led to a reduction in biofilm formation. However, unlike the motility of P. putida, the motility of the P. aeruginosa mutants was unaffected. Our data illustrate a novel developmentally regulated sensory and signaling pathway for several properties required for virulence and ecological fitness of Pseudomonas species.

scholarly journals Comparison of Botryococcus braunii and Neochloris vigensis Biofilm Formation on Vertical Oriented Surfaces

2021 ◽  
Vol 11 (5) ◽  
pp. 12843-12857
Keyword(s):  
Biofilm Formation ◽  
Cell Concentration ◽  
Surface Characteristics ◽  
Cost Effective ◽  
Botryococcus Braunii ◽  
Total Proteins ◽  
Chl A ◽  
Algal Strain ◽  
Microalgae Biomass ◽  
Hydrophilic Materials

Biofilm technology is a cost-effective process for microalgae biomass production. Materials can be successfully used as microalgae biomass adhesion carriers. The productivity of two different microalgal strains, Neochloris vigensis, and Botryococcus braunii, were compared in an opened pond system on eleven different surfaces (cork, sponge towel, denim, plexiglass, stainless steel, silicone rubber, glass, geotextile, and three different patterned plexiglass). Biomass attachment on the various materials was monitored for 16 days of cultivation. Various parameters were tested during cultivation, such as pH, cell concentration, chl-a, NO3-, PO43-, lipids, total proteins, and carbohydrates. Contact angle and surface energy were used to determine the surface characteristics. Plexiglass resulted in the best performance in the case of B.braunii (28.3 g/m2), while in the case of N.vigensis, sponge towel exhibited the highest productivity (17.8 g/m2). Based on the results, the algal strain affects the attachment, and hydrophilic materials can be as efficient as hydrophobic ones.

scholarly journals Induction of native c-di-GMP phosphodiesterases leads to dispersal of Pseudomonas aeruginosa biofilms

2021 ◽  
Author(s):  
Jens Bo Andersen ◽  
Kasper Nørskov Kragh ◽  
Louise Dahl Hultqvist ◽  
Morten Rybtke ◽  
Martin Nilsson ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Single Cell ◽  
Biofilm Formation ◽  
Ectopic Expression ◽  
Second Messenger ◽  
Flow Cell ◽  
Diguanylate Cyclases ◽  
Biofilm Dispersal ◽  
High Level

A decade of research has shown that the molecule c-di-GMP functions as a central second messenger in many bacteria. A high level of c-di-GMP is associated with biofilm formation whereas a low level of c-di-GMP is associated with a planktonic single-cell bacterial lifestyle. C-di-GMP is formed by diguanylate cyclases and is degraded by specific phosphodiesterases. We have previously presented evidence that ectopic expression in Pseudomonas aeruginosa of the Escherichia coli phosphodiesterase YhjH results in biofilm dispersal. More recently, however, evidence has been presented that induction of native c-di-GMP phosphodiesterases does not lead to dispersal of P. aeruginosa biofilms. The latter result may discourage attempts to use c-di-GMP signaling as a target for development of anti-biofilm drugs. However, here we demonstrate that induction of the P. aeruginosa c-di-GMP phosphodiesterases PA2133 and BifA indeed does result in dispersal of P. aeruginosa biofilms in both a microtiter tray biofilm assay and in a flow-cell biofilm system.

scholarly journals Impact of γ-irradiation on biofilm-formation by corrosion-relevant heterotrophic bacteria

2020 ◽  
Author(s):  
M. Boretska ◽  
◽  
K. Shavanova ◽  
Yu. Ruban ◽  
O. Pareniuk ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Biofilm Formation ◽  
Nuclear Power ◽  
Heterotrophic Bacteria ◽  
Soil Microbial Communities ◽  
Planktonic Cell ◽  
Γ Irradiation ◽  
Metal Structures ◽  
Microbially Influenced Corrosion ◽  
The Impact

At nuclear hazard sites, such as the Chernobyl reactor sarcophagus or Fukushima Nuclear Power Plant, radiation is one of the main factors influencing microbial communities including those involved in microbially influenced corrosion (MIC) of metal structures. By studying the impact of radiation on corrosion-relevant bacteria it may be possible in the future to predict changes in MIC. We believe that the composition and function of natural multi-species biofilms will change when exposed to the stress of ionizing radiation. To address this possibility, biofilm formation by Pseudomonas pseudoalcaligenes and Stenotrophomonas maltophilia were studied after exposure to a range of radiation dosages. Altered planktonic cell morphologies and biofilm architectures on submerged glass surfaces were noted 3 – 7 days after low-doasage sub-lethal irradiation (5.3 Gy) of samples at the micro-colony, macro-colony and mature biofilm stages of development. Furthermore, significant differences in the percentage area covered by biofilms and the release of viable planktonic cells was also noted. These observations suggested that exposure, considered as insignificant levels of irradiation, can be enough to alter biofilm formation of corrosion-relevant bacteria. Such low dosage radiation may have significant impact on soil microbial communities in nuclear hazard sites, potentially altering the MIC of exposed metal structures, their stability and service life of underground metal constructions.

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