scholarly journals Microbial Adhesion and Biofilm Formation on Microfiltration Membranes: A Detailed Characterization Using Model Organisms with Increasing Complexity

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
L. Vanysacker ◽  
C. Denis ◽  
P. Declerck ◽  
A. Piasecka ◽  
I. F. J. Vankelecom
Keyword(s):  
Membrane Fouling ◽  
Biofilm Formation ◽  
Bacterial Community Composition ◽  
Microbial Interactions ◽  
Model Systems ◽  
Model Organisms ◽  
Microbial Adhesion ◽  
Membrane Biofouling ◽  
Microfiltration Membranes ◽  
Cell Densities

Since many years, membrane biofouling has been described as the Achilles heel of membrane fouling. In the present study, an ecological assay was performed using model systems with increasing complexity: a monospecies assay usingPseudomonas aeruginosaorEscherichia coliseparately, a duospecies assay using both microorganisms, and a multispecies assay using activated sludge with or without spikedP. aeruginosa. The microbial adhesion and biofilm formation were evaluated in terms of bacterial cell densities, species richness, and bacterial community composition on polyvinyldifluoride, polyethylene, and polysulfone membranes. The data show that biofouling formation was strongly influenced by the kind of microorganism, the interactions between the organisms, and the changes in environmental conditions whereas the membrane effect was less important. The findings obtained in this study suggest that more knowledge in species composition and microbial interactions is needed in order to understand the complex biofouling process. This is the first report describing the microbial interactions with a membrane during the biofouling development.

scholarly journals Inhibitory Effect of Vanillin on Biofilm Formation by Multi-Species Wastewater Culture

2020 ◽  
Vol 23 (4) ◽  
pp. 274-279
Author(s):  
Xiurong Si ◽  
Ding Ding ◽  
Jianhua Zhou ◽  
Zhangwei Cao
Keyword(s):  
Membrane Fouling ◽  
Biofilm Formation ◽  
Extracellular Polymeric Substances ◽  
Inhibitory Effect ◽  
Inhibition Rate ◽  
Microbial Adhesion ◽  
Fouling Control ◽  
Microfluidic Chamber ◽  
Research Findings ◽  
Static Conditions

This paper mainly investigates the inhibitory effect and mechanism of vanillin on mixed-culture biofilm formation, and discusses the feasibility of controlling membrane fouling with vanillin. The biofilms were cultured under static conditions and a microfluidic chamber, respectively. The results show that vanillin can effectively inhibit the microbial adhesion and biofilm formation; the inhibition rate increases with the vanillin concentration. After 12h treatment with 300mg/L vanillin, the inhibition rate of biofilm formation reached 85.34%. Besides, vanillin can mitigate bacterial adhesion by reducing the microbial secretion of exoprotein and exopolysaccharide, exhibit an inhibitory effect on the expression of N-acyl-l-homoserine lactones (AHLs), but had no effect on environmental deoxyribonucleic acid (eDNA). After being treated with 300mg/L vanillin, exoprotein, exopolysaccharide and AHLs decreased by 28.48%, 17.23% and 46.64%, respectively. Furthermore, there is a positive correlation between the AHLs and the content of extracellular polymeric substances (EPSs); the AHLs-mediated quorum sensing (QS) might be related to microbial adhesion through the regulation of EPS. Finally, vanillin has a great potential in membrane fouling control. The research findings provide a good reference for biofilm control in water purification and wastewater treatment systems.

scholarly journals Silver-Palladium Surfaces Inhibit Biofilm Formation

2009 ◽  
Vol 75 (6) ◽  
pp. 1674-1678 ◽  
Author(s):  
Wen-Chi Chiang ◽  
Casper Schroll ◽  
Lisbeth Rischel Hilbert ◽  
Per Møller ◽  
Tim Tolker-Nielsen
Keyword(s):  
Biofilm Formation ◽  
Bacterial Load ◽  
Flow Chamber ◽  
Model Systems ◽  
Model Organisms ◽  
Inhibition Mechanism ◽  
Biofilm Inhibition ◽  
Palladium Surface ◽  
High Bacterial Load ◽  
Silver Palladium

ABSTRACT Undesired biofilm formation is a major concern in many areas. In the present study, we investigated biofilm-inhibiting properties of a silver-palladium surface that kills bacteria by generating microelectric fields and electrochemical redox processes. For evaluation of the biofilm inhibition efficacy and study of the biofilm inhibition mechanism, the silver-sensitive Escherichia coli J53 and the silver-resistant E. coli J53[pMG101] strains were used as model organisms, and batch and flow chamber setups were used as model systems. In the case of the silver-sensitive strain, the silver-palladium surfaces killed the bacteria and prevented biofilm formation under conditions of low or high bacterial load. In the case of the silver-resistant strain, the silver-palladium surfaces killed surface-associated bacteria and prevented biofilm formation under conditions of low bacterial load, whereas under conditions of high bacterial load, biofilm formation occurred upon a layer of surface-associated dead bacteria.

scholarly journals The Queen Gut Refines with Age: Longevity Phenotypes in a Social Insect Model

2018 ◽  
Author(s):  
Kirk E. Anderson ◽  
Vincent A. Ricigliano ◽  
Brendon M. Mott ◽  
Duan C. Copeland ◽  
Amy S. Floyd ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Gut Microbiota ◽  
Honey Bee ◽  
Honey Bees ◽  
Bacterial Species ◽  
Microbial Interactions ◽  
Model Systems ◽  
Model Organisms ◽  
Biological Aging ◽  
Microbial Succession

AbstractBackgroundIn social insects, identical genotypes can show extreme lifespan variation providing a unique perspective on age-associated microbial succession. In honey bees, short and long-lived host phenotypes are polarized by a suite of age-associated factors including hormones, nutrition, immune senescence and oxidative stress. Similar to other model organisms, the aging gut microbiota of short-lived (worker) honey bees accrue Proteobacteria and are depleted of Lactobacillus and Bifidobacterium, consistent with a suite of host senescence markers. In contrast, long-lived (queen) honey bees maintain youthful cellular function without expressing oxidative stress genes, suggesting a very different host environment for age-associated microbial succession.ResultsWe sequenced the microbiota of 63 honey bee queens exploring two chronological ages and four alimentary tract niches. To control for individual variation we quantified carbonyl accumulation in queen fat body tissue as a proxy for biological aging. We compared our results to the age-specific microbial succession of worker guts. Accounting for queen source variation, two or more bacterial species per niche differed significantly by queen age. Biological aging in queens was correlated with microbiota composition highlighting the relationship of microbiota with oxidative stress. Queens and workers shared many major gut bacterial species, but differ markedly in community structure and age succession. In stark contrast to aging workers, carbonyl accumulation in queens was significantly associated with increased Lactobacillus and Bifidobacterium and depletion of various Proteobacteria.ConclusionsWe present a model system linking changes in gut microbiota to diet and longevity, two of the most confounding variables in human microbiota research. As described for other model systems, metabolic changes associated with diet and host longevity correspond to the changing microbiota. The pattern of age-associated succession in the queen microbiota is largely the reverse of that demonstrated for workers. The guts of short-lived worker phenotypes are progressively dominated by three major Proteobacteria, but these same species were sparse or significantly depleted in long-lived queen phenotypes. More broadly, our results suggest that lifespan evolution formed the context for host-microbial interactions and age-related succession of honey bee microbiota.

scholarly journals Interaction of Acinetobacter baumannii with Human Serum Albumin: Does the Host Determines the Outcome?

Antibiotics ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 833
Author(s):  
Camila Pimentel ◽  
Casin Le ◽  
Marisel R. Tuttobene ◽  
Tomas Subils ◽  
Krisztina M. Papp-Wallace ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Human Serum Albumin ◽  
Quorum Sensing ◽  
Serum Albumin ◽  
Human Serum ◽  
Acinetobacter Baumannii ◽  
Biofilm Formation ◽  
Model Systems ◽  
Expression Levels ◽  
Multiple Drugs

Acinetobacter baumannii has become a serious threat to human health due to its extreme antibiotic resistance, environmental persistence, and capacity to survive within the host. Two A. baumannii strains, A118 and AB5075, commonly used as model systems, and three carbapenem-resistant strains, which are becoming ever more dangerous due to the multiple drugs they can resist, were exposed to 3.5% human serum albumin (HSA) and human serum (HS) to evaluate their response with respect to antimicrobial resistance, biofilm formation, and quorum sensing, all features responsible for increasing survival and persistence in the environment and human body. Expression levels of antibiotic resistance genes were modified differently when examined in different strains. The cmlA gene was upregulated or downregulated in conditions of exposure to 3.5% HSA or HS depending on the strain. Expression levels of pbp1 and pbp3 tended to be increased by the presence of HSA and HS, but the effect was not seen in all strains. A. baumannii A118 growing in the presence of HS did not experience increased expression of these genes. Aminoglycoside-modifying enzymes were also expressed at higher or lower levels in the presence of HSA or HS. Still, the response was not uniform; in some cases, expression was enhanced, and in other cases, it was tapered. While A. baumannii AB5075 became more susceptible to rifampicin in the presence of 3.5% HSA or HS, strain A118 did not show any changes. Expression of arr2, a gene involved in resistance to rifampicin present in A. baumannii AMA16, was expressed at higher levels when HS was present in the culture medium. HSA and HS reduced biofilm formation and production of N-Acyl Homoserine Lactone, a compound intimately associated with quorum sensing. In conclusion, HSA, the main component of HS, stimulates a variety of adaptative responses in infecting A. baumannii strains.

Abstract 426: Laminin Downregulation Facilitates Cardiomyocyte Coupling in situ to Increase Contractile Function

2016 ◽  
Vol 119 (suppl_1) ◽  
Author(s):  
Ayla Sessions ◽  
Gaurav Kaushik ◽  
Adam Engler
Keyword(s):  
Basement Membrane ◽  
Contractile Function ◽  
Current Model ◽  
Model Systems ◽  
Model Organisms ◽  
Muscle Physiology ◽  
Heart Tube ◽  
Age Related ◽  
New Evidence

Aging is associated with extensive remodeling of the heart, including basement membrane extracellular matrix (ECM) components that surround cardiomyocytes. Remodeling is thought to contribute to impaired cardiac mechanotransduction, but the contribution of specific basement membrane ECM components to age-related cardiac remodeling is unclear, owing to current model systems being complex and slow to age. To investigate the effect of basement membrane remodeling on mechanical function in genetically tractable, rapidly aging, and simple model organisms, we employed Drosophila melanogaster, which has a simple trilayered heart tube composed of only basement membrane ECM. We observed differential regulation of collagens between laboratory Drosophila strains , i.e. yellow-white ( yw ) and white-1118 ( w 1118 ), leading to changes in muscle physiology, which were linked to severity of dysfunction with age. Therefore, we sought to understand the extent to which basement membrane ECM modulates lateral cardiomyocyte coupling and contractile function during aging. Cardiac-restricted knockdown of ECM genes Pericardin , Laminin A , and Viking in Drosophila prevented age-associated heart tube restriction and increased contractility, even under viscous load. Most notably, reduction of Laminin A expression decreased levels of other genes that co-assemble in ECM, leading to overall preservation of contractile velocity and extension of median organismal lifespan by 3 weeks or 39%. These data provide new evidence of a direct link between basement membrane ECM homeostasis, contractility, and maintenance of lifespan.

Abstract 371: Down Regulation of ECM Genes Laminin and Collagen IV Lead to Preserved Cardiac Function With Age and Increased Lifespan in Drosophila

2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Ayla O Sessions
Keyword(s):  
Diastolic Dysfunction ◽  
High Speed ◽  
Current Model ◽  
Collagen Iv ◽  
Model Systems ◽  
Model Organisms ◽  
Heart Tube ◽  
Ecm Remodeling ◽  
Intercalated Discs ◽  
And Performance

Increased deposition of extracellular matrix (ECM) is observed in all advanced age heart failure patients, but current model systems are complex and slow to age. To investigate the effect of extracellular remodeling on mechanical function in genetically tractable, rapidly aging, and simple model organisms, we employed Drosophila melanogaster, which has a simple trilayered heart tube. We found that two common wildtype strains of Drosophila, i.e. yellow-white (yw) and white-1118 (w1118), exhibit different cytoskeletal and ECM remodeling with age. Using a recently developed nanoindentation method to measure cardiomyocyte stiffness and high speed optical imaging to assess contractility of intact Drosophila hearts, we found that yw flies had stiffer intercalated discs (ICD) and exhibited diastolic dysfunction with age. On the other hand, w1118 flies had a shorter lifespan compared to yw, did not exhibit ICD stiffening, had a less severe diastolic dysfunction, and showed an increase in ECM layer thickness between ventral muscle (VM) and cardiomyocyte (CM) layers of the heart tube. To modulate ECM and assess its effect in the aged w1118 flies, we knocked-down ECM genes LamininA and Viking (homologous to Collagen IV). Both ECM KD genotypes exhibited diastolic dilation with increased fractional shortening at adult (1wk) and aged (5wk) time points. The LamininA KD resulted in decreased cardiomyocyte stiffness correlating with increased relaxation velocities in adult flies and preservation of shortening and relaxation velocities in aged flies over controls. However, both the LamininA and Collagen IV KD flies experienced a basal increase in the decoupling of their cardiomyocytes as determined by heart period variance and % fibrillar heart-beats. These conductance issues were not enough to counteract the increased cardiac output and performance with age, and the Collagen IV KD outlived controls by 1.5 weeks median survival and the LamininA KD by 3 weeks. This suggests that the cell-ECM contacts in the basement membrane are intimately tied not only to the coupling of the cardiomyocytes of the Drosophila heart tube but also to cytoskeletal remodeling, but perhaps different ECM proteins have different mechanisms for interacting with the cardiomyocyte cytoskeleton.

Differential surface competition and biofilm invasion strategies of Pseudomonas aeruginosa PA14 and PAO1

2021 ◽  
Author(s):  
Swetha Kassety ◽  
Stefan Katharios-Lanwermeyer ◽  
George A. O’Toole ◽  
Carey D. Nadell
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Matrix Composition ◽  
Model Organisms ◽  
Culture Methods ◽  
Biofilm Growth ◽  
Biofilm Production ◽  
Direct Competition ◽  
Planktonic Phase ◽  
Do So

Pseudomonas aeruginosa strains PA14 and PAO1 are among the two best characterized model organisms used to study the mechanisms of biofilm formation, while also representing two distinct lineages of P. aeruginosa . Previous work has shown that PA14 and PAO1 use different strategies for surface colonization; they also have different extracellular matrix composition and different propensities to disperse from biofilms back into the planktonic phase surrounding them. We expand on this work here by exploring the consequences of these different biofilm production strategies during direct competition. Using differentially labeled strains and microfluidic culture methods, we show that PAO1 can outcompete PA14 in direct competition during early colonization and subsequent biofilm growth, that they can do so in constant and perturbed environments, and that this advantage is specific to biofilm growth and requires production of the Psl polysaccharide. In contrast, the P. aeruginosa PA14 is better able to invade pre-formed biofilms and is more inclined to remain surface-associated under starvation conditions. These data together suggest that while P. aeruginosa PAO1 and PA14 are both able to effectively colonize surfaces, they do so in different ways that are advantageous under different environmental settings. Importance Recent studies indicate that P. aeruginosa PAO1 and PA14 use distinct strategies to initiate biofilm formation. We investigated whether their respective colonization and matrix secretion strategies impact their ability to compete under different biofilm-forming regimes. Our work shows that these different strategies do indeed impact how these strains fair in direct competition: PAO1 dominates during colonization of a naïve surface, while PA14 is more effective in colonizing a pre-formed biofilm. These data suggest that even for very similar microbes there can be distinct strategies to successfully colonize and persist on surfaces during the biofilm life cycle.

scholarly journals Bacillus velezensisWall Teichoic Acids Are Required for Biofilm Formation and Root Colonization

2018 ◽  
Vol 85 (5) ◽  
Author(s):  
Zhihui Xu ◽  
Huihui Zhang ◽  
Xinli Sun ◽  
Yan Liu ◽  
Wuxia Yan ◽  
...  
Keyword(s):  
Plant Growth ◽  
Biofilm Formation ◽  
Root Colonization ◽  
Molecular Networks ◽  
Model Organisms ◽  
Bacillus Velezensis ◽  
Content Type ◽  
Plant Growth Promoting ◽  
Colonization Process ◽  
Growth Promoting

ABSTRACTRhizosphere colonization by plant growth-promoting rhizobacteria (PGPR) along plant roots facilitates the ability of PGPR to promote plant growth and health. Thus, an understanding of the molecular mechanisms of the root colonization process by plant-beneficialBacillusstrains is essential for the use of these strains in agriculture. Here, we observed that ansfpgene mutant of the plant growth-promoting rhizobacteriumBacillus velezensisSQR9 was unable to form normal biofilm architecture, and differential protein expression was observed by proteomic analysis. A minor wall teichoic acid (WTA) biosynthetic protein, GgaA, was decreased over 4-fold in the Δsfpmutant, and impairment of theggaAgene postponed biofilm formation and decreased cucumber root colonization capabilities. In addition, we provide evidence that the major WTA biosynthetic enzyme GtaB is involved in both biofilm formation and root colonization. The deficiency in biofilm formation of the ΔgtaBmutant may be due to an absence of UDP-glucose, which is necessary for the synthesis of biofilm matrix exopolysaccharides (EPS). These observations provide insights into the root colonization process by a plant-beneficialBacillusstrain, which will help improve its application as a biofertilizer.IMPORTANCEBacillus velezensisis a Gram-positive plant-beneficial bacterium which is widely used in agriculture. Additionally,Bacillusspp. are some of the model organisms used in the study of biofilms, and as such, the molecular networks and regulation systems of biofilm formation are well characterized. However, the molecular processes involved in root colonization by plant-beneficialBacillusstrains remain largely unknown. Here, we showed that WTAs play important roles in the plant root colonization process. The loss of thegtaBgene affects the ability ofB. velezensisSQR9 to sense plant polysaccharides, which are important environmental cues that trigger biofilm formation and colonization in the rhizosphere. This knowledge provides new insights into theBacillusroot colonization process and can help improve our understanding of plant-rhizobacterium interactions.

scholarly journals A circadian clock in Saccharomyces cerevisiae

2010 ◽  
Vol 107 (5) ◽  
pp. 2043-2047 ◽  
Author(s):  
Zheng Eelderink-Chen ◽  
Gabriella Mazzotta ◽  
Marcel Sturre ◽  
Jasper Bosman ◽  
Till Roenneberg ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Genetic Model ◽  
Circadian Clocks ◽  
Model Systems ◽  
Model Organisms ◽  
Biological Clocks ◽  
Experimental Systems ◽  
Fundamental Biological Process ◽  
Free Running ◽  
And Behavior

Circadian timing is a fundamental biological process, underlying cellular physiology in animals, plants, fungi, and cyanobacteria. Circadian clocks organize gene expression, metabolism, and behavior such that they occur at specific times of day. The biological clocks that orchestrate these daily changes confer a survival advantage and dominate daily behavior, for example, waking us in the morning and helping us to sleep at night. The molecular mechanism of circadian clocks has been sketched out in genetic model systems from prokaryotes to humans, revealing a combination of transcriptional and posttranscriptional pathways, but the clock mechanism is far from solved. Although Saccharomyces cerevisiae is among the most powerful genetic experimental systems and, as such, could greatly contribute to our understanding of cellular timing, it still remains absent from the repertoire of circadian model organisms. Here, we use continuous cultures of yeast, establishing conditions that reveal characteristic clock properties similar to those described in other species. Our results show that metabolism in yeast shows systematic circadian entrainment, responding to cycle length and zeitgeber (stimulus) strength, and a (heavily damped) free running rhythm. Furthermore, the clock is obvious in a standard, haploid, auxotrophic strain, opening the door for rapid progress into cellular clock mechanisms.

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