Characterizing biofilms for biofouling and microbial corrosion control in cooling water systems

2016 ◽  
Vol 63 (6) ◽  
pp. 477-489 ◽  
Author(s):  
R.P. George ◽  
U. Kamachi Mudali ◽  
Baldev Raj
Keyword(s):  
Biofilm Formation ◽  
Corrosion Behaviour ◽  
Control Strategies ◽  
Bacterial Species ◽  
Cooling Water ◽  
Water Systems ◽  
Microbiologically Influenced Corrosion ◽  
Mitigation Measures ◽  
Content Type ◽  
Physiological Diversity

Purpose The purpose of this paper is to study the metal-Microbe interaction playing a crucial role in microbiologically influenced corrosion (MIC) and biofouling of materials in cooling water systems. Treatment regimens should be planned based on this understanding. Design/methodology/approach Attempts were made in the past decades to characterize and understand biofilm formation on important power plant structural materials such as carbon steel (CS), stainless steel (SS) and titanium in fresh water and in seawater to achieve better control of biofouling and minimize MIC problems. Findings This report presents the results of detailed studies on tuberculation-formed CS because of the action of iron-oxidizing bacteria and the effects of algae- and bacteria-dominated biofilms on the passivity of SS. The preferential adhesion of different bacterial species on SS under the influence of inclusions and sensitization was studied in the context of preferential corrosion of SS weldments due to microbial action. Detailed characterization of biofilms formed on titanium (the likely condenser material for fast breeder reactors) after exposure for two years in Kalpakkam coastal waters revealed intense biofouling and biomineralization of manganese even in chlorinated seawater. Studies on the effectiveness of conventional fouling control strategies were also evaluated. Originality/value The detailed studies of different metal/biofilm/microbe interactions demonstrated the physiological diversity of microbes in the biofilms that were formed on different materials, coupling their cooperative metabolic activities with consequent corrosion behaviour. These interactions could enhance either anodic or cathodic reactions and exploit metallurgical features that enhance biofilm formation and/or the capacity of microbes to mutate and overcome mitigation measures.

scholarly journals Linearmycins Activate a Two-Component Signaling System Involved in Bacterial Competition and Biofilm Morphology

2017 ◽  
Vol 199 (18) ◽  
Author(s):  
Reed M. Stubbendieck ◽  
Paul D. Straight
Keyword(s):  
Antibiotic Resistance ◽  
Abc Transporter ◽  
Bacterial Communities ◽  
Biofilm Formation ◽  
Bacterial Species ◽  
Bioactive Metabolites ◽  
Signaling System ◽  
Content Type ◽  
Two Component ◽  
Analytical Approaches

ABSTRACT Bacteria use two-component signaling systems to adapt and respond to their competitors and changing environments. For instance, competitor bacteria may produce antibiotics and other bioactive metabolites and sequester nutrients. To survive, some species of bacteria escape competition through antibiotic production, biofilm formation, or motility. Specialized metabolite production and biofilm formation are relatively well understood for bacterial species in isolation. How bacteria control these functions when competitors are present is not well studied. To address fundamental questions relating to the competitive mechanisms of different species, we have developed a model system using two species of soil bacteria, Bacillus subtilis and Streptomyces sp. strain Mg1. Using this model, we previously found that linearmycins produced by Streptomyces sp. strain Mg1 cause lysis of B. subtilis cells and degradation of colony matrix. We identified strains of B. subtilis with mutations in the two-component signaling system yfiJK operon that confer dual phenotypes of specific linearmycin resistance and biofilm morphology. We determined that expression of the ATP-binding cassette (ABC) transporter yfiLMN operon, particularly yfiM and yfiN, is necessary for biofilm morphology. Using transposon mutagenesis, we identified genes that are required for YfiLMN-mediated biofilm morphology, including several chaperones. Using transcriptional fusions, we found that YfiJ signaling is activated by linearmycins and other polyene metabolites. Finally, using a truncated YfiJ, we show that YfiJ requires its transmembrane domain to activate downstream signaling. Taken together, these results suggest coordinated dual antibiotic resistance and biofilm morphology by a single multifunctional ABC transporter promotes competitive fitness of B. subtilis. IMPORTANCE DNA sequencing approaches have revealed hitherto unexplored diversity of bacterial species in a wide variety of environments that includes the gastrointestinal tract of animals and the rhizosphere of plants. Interactions between different species in bacterial communities have impacts on our health and industry. However, many approaches currently used to study whole bacterial communities do not resolve mechanistic details of interspecies interactions, including how bacteria sense and respond to their competitors. Using a competition model, we have uncovered dual functions for a previously uncharacterized two-component signaling system involved in specific antibiotic resistance and biofilm morphology. Insights gleaned from signaling within interspecies interaction models build a more complete understanding of gene functions important for bacterial communities and will enhance community-level analytical approaches.

scholarly journals Quorum Sensing Influences Burkholderia thailandensis Biofilm Development and Matrix Production

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 ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Biofilm Formation ◽  
Bacterial Species ◽  
Matrix Material ◽  
Close Relative ◽  
Wild Type ◽  
Flow Conditions ◽  
Burkholderia Thailandensis ◽  
Content Type ◽  
Biofilm Development

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.

scholarly journals Formation of Staphylococcus aureus Biofilm in the Presence of Sublethal Concentrations of Disinfectants Studied via a Transcriptomic Analysis Using Transcriptome Sequencing (RNA-seq)

2017 ◽  
Vol 83 (24) ◽  
Author(s):  
M. Slany ◽  
J. Oppelt ◽  
L. Cincarova
Keyword(s):  
Gene Expression ◽  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Transcriptome Sequencing ◽  
Expression Profiles ◽  
Bacterial Species ◽  
Rna Seq ◽  
Altered Expression ◽  
Content Type ◽  
Sublethal Concentrations

ABSTRACT Staphylococcus aureus is a common biofilm-forming pathogen. Low doses of disinfectants have previously been reported to promote biofilm formation and to increase virulence. The aim of this study was to use transcriptome sequencing (RNA-seq) analysis to investigate global transcriptional changes in S. aureus in response to sublethal concentrations of the commonly used food industry disinfectants ethanol (EtOH) and chloramine T (ChT) and their combination (EtOH_ChT) in order to better understand the effects of these agents on biofilm formation. Treatment with EtOH and EtOH_ChT resulted in more significantly altered expression profiles than treatment with ChT. Our results revealed that EtOH and EtOH_ChT treatments enhanced the expression of genes responsible for regulation of gene expression (sigB), cell surface factors (clfAB), adhesins (sdrDE), and capsular polysaccharides (cap8EFGL), resulting in more intact biofilm. In addition, in this study we were able to identify the pathways involved in the adaptation of S. aureus to the stress of ChT treatment. Further, EtOH suppressed the effect of ChT on gene expression when these agents were used together at sublethal concentrations. These data show that in the presence of sublethal concentrations of tested disinfectants, S. aureus cells trigger protective mechanisms and try to cope with them. IMPORTANCE So far, the effect of disinfectants is not satisfactorily explained. The presented data will allow a better understanding of the mode of disinfectant action with regard to biofilm formation and the ability of bacteria to survive the treatment. Such an understanding could contribute to the effort to eliminate possible sources of bacteria, making disinfectant application as efficient as possible. Biofilm formation plays significant role in the spread and pathogenesis of bacterial species.

scholarly journals LitR of Vibrio salmonicida Is a Salinity-Sensitive Quorum-Sensing Regulator of Phenotypes Involved in Host Interactions and Virulence

2012 ◽  
Vol 80 (5) ◽  
pp. 1681-1689 ◽  
Author(s):  
Ane Mohn Bjelland ◽  
Henning Sørum ◽  
Daget Ayana Tegegne ◽  
Hanne C. Winther-Larsen ◽  
Nils Peder Willassen ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Biofilm Formation ◽  
Molecular Mechanisms ◽  
Cold Water ◽  
Bacterial Species ◽  
Cell Communication ◽  
Cell Aggregation ◽  
Fish Host ◽  
Content Type ◽  
Vibrio Salmonicida

ABSTRACTVibrio(Aliivibrio)salmonicidais the causal agent of cold-water vibriosis, a fatal bacterial septicemia primarily of farmed salmonid fish. The molecular mechanisms of invasion, colonization, and growth ofV. salmonicidain the host are still largely unknown, and few virulence factors have been identified. Quorum sensing (QS) is a cell-to-cell communication system known to regulate virulence and other activities in several bacterial species. The genome ofV. salmonicidaLFI1238 encodes products presumably involved in several QS systems. In this study, the gene encoding LitR, a homolog of the master regulator of QS inV. fischeri, was deleted. Compared to the parental strain, thelitRmutant showed increased motility, adhesion, cell-to-cell aggregation, and biofilm formation. Furthermore, thelitRmutant produced less cryptic bioluminescence, whereas production of acylhomoserine lactones was unaffected. Our results also indicate a salinity-sensitive regulation of LitR. Finally, reduced mortality was observed in Atlantic salmon infected with thelitRmutant, implying that the fish were more susceptible to infection with the wild type than with the mutant strain. We hypothesize that LitR inhibits biofilm formation and favors planktonic growth, with the latter being more adapted for pathogenesis in the fish host.

Biofilm Formation on NiTi Surface by Different Strains of Sulphate Reducing Bacteria (Desulfovibrio desulfuricans)

2015 ◽  
Vol 227 ◽  
pp. 302-305 ◽  
Author(s):  
Beata Cwalina ◽  
Weronika Dec ◽  
Wojciech Simka ◽  
Joanna Michalska ◽  
Marzena Jaworska-Kik
Keyword(s):  
Biofilm Formation ◽  
Niti Alloy ◽  
Bacterial Species ◽  
Desulfovibrio Desulfuricans ◽  
Microbiologically Influenced Corrosion ◽  
Sulphate Reducing Bacteria ◽  
Electrochemical Processes ◽  
Soil Strain ◽  
Different Strains ◽  
Reducing Bacteria

Bacteria of Desulfovibrio genus belong to group of widespread sulphate-reducing bacteria (SRB). D. desulfuricans is considered one among many bacterial species involved in microbiologically influenced corrosion (MIC) of metals, mainly of stainless steels and other alloys. SRB can produce gaseous hydrogen sulphide. This gas is released into the environment leading to formation of metal sulphides that significantly influence electrochemical processes and ultimately enhance the corrosion of materials. Biofilms formed by these bacteria are especially harmful for highly alloyed steels and many alloys. The aim of this work was to compare the character of growth and biofilm formation by three strains of D. desulfuricans (standard soil strain DSM and two wild intestinal strains: DV/A and DV/B) on the surface of NiTi alloy.

scholarly journals Interaction between Streptococcus spp. and Veillonella tobetsuensis in the Early Stages of Oral Biofilm Formation

2015 ◽  
Vol 197 (13) ◽  
pp. 2104-2111 ◽  
Author(s):  
Izumi Mashima ◽  
Futoshi Nakazawa
Keyword(s):  
Biofilm Formation ◽  
Bacterial Species ◽  
Signaling Molecules ◽  
Dependent Manner ◽  
Oral Biofilm ◽  
Metabolic Cooperation ◽  
Content Type ◽  
Early Stages ◽  
Oral Biofilms ◽  
Culture Supernatants

Dental plaque is a multispecies oral biofilm, the development of which is initiated by adherence of the pioneerStreptococcusspp. OralVeillonellaspp., includingV. atypica,V. denticariosi,V. dispar,V. parvula,V. rogosae, andV. tobetsuensis, are known as early colonizers in oral biofilm formation. These species have been reported to coaggregate withStreptococcusspp. in a metabolic cooperation-dependent manner to form biofilms in human oral cavities, especially in the early stages of biofilm formation. However, in our previous study,Streptococcus gordoniishowed biofilm formation to the greatest extent in the presence ofV. tobetsuensis, without coaggregation between species. These results suggest thatV. tobetsuensisproduces signaling molecules that promote the proliferation ofS. gordoniiin biofilm formation. It is well known in many bacterial species that the quorum-sensing (QS) system regulates diverse functions such as biofilm formation. However, little is known about the QS system with autoinducers (AIs) with respect toVeillonella and Streptococcusspp. Recently, autoinducer 1 (AI-1) and AI-2 were detected and identified in the culture supernatants ofV. tobetsuensisas strong signaling molecules in biofilm formation withS. gordonii. In particular, the supernatant fromV. tobetsuensisshowed the highest AI-2 activity among 6 oralVeillonellaspecies, indicating that AIs, mainly AI-2, produced byV. tobetsuensismay be important factors and may facilitate biofilm formation ofS. gordonii. Clarifying the mechanism that underlies the QS system betweenS. gordoniiandV. tobetsuensismay lead to the development of novel methods for the prevention of oral infectious diseases caused by oral biofilms.

scholarly journals Effects of a Novel Probiotic Combination on Pathogenic Bacterial-Fungal Polymicrobial Biofilms

mBio ◽  
2019 ◽  
Vol 10 (2) ◽  
Author(s):  
Christopher L. Hager ◽  
Nancy Isham ◽  
Kory P. Schrom ◽  
Jyotsna Chandra ◽  
Thomas McCormick ◽  
...  
Keyword(s):  
Inflammatory Bowel Diseases ◽  
Gut Microbiome ◽  
Biofilm Formation ◽  
Bacterial Species ◽  
Bacterial Flora ◽  
Confocal Scanning Laser Microscopy ◽  
Antibiofilm Activity ◽  
Content Type ◽  
Bowel Diseases ◽  
Inflammatory Bowel

ABSTRACTDysbiosis of the gut microbiome has been implicated in inflammatory bowel diseases. We have shown that levels ofCandida tropicalis, along with those ofEscherichia coliandSerratia marcescens, are significantly elevated in Crohn’s disease (CD) patients. Here, we evaluated the ability of a novel probiotic to prevent and treat polymicrobial biofilms (PMB) formed byC. tropicaliswithE. coliandS. marcescens. SinceCandida albicanshas been reported to be elevated in CD patients, we investigated the interactions ofC. albicanswith these bacterial species in biofilm formation. We determined whether the interaction betweenCandidaspp. and bacteria is specific by usingTrichosporon inkinandSaccharomyces fibuligeraas comparators. Additionally, the effects of probiotics onC. albicansgermination and biofilm formation were determined. To determine the ability of the probiotic to prevent or treat mature biofilms, probiotic filtrate was added to the PMB at early (prevention) and mature (treatment) phases. Biofilm thickness and architecture were assessed by confocal scanning laser microscopy. The effects of the probiotic on germination were evaluated in the presence of serum. Exposure ofC. tropicalisPMB to probiotic filtrate reduced biofilm matrix, decreased thickness, and inhibited hyphal formation. We showed thatC. albicansorC. tropicalisformed significantly thicker PMB than control biofilms, indicating that this interaction isCandidaspecific. Treatment with probiotic filtrate inhibitedC. albicansgermination and prevented/treatedC. albicansPMB. The designed probiotic may have utility in the management of biofilm-associated gastrointestinal diseases such as Crohn’s and colorectal cancer.IMPORTANCEThe effects of diversity of the gut microbiome on inflammation have centered mainly on bacterial flora. Recent research has implicated fungal species and their interactions with other organisms in the inflammatory process. New ways to restore microbial balance in the gut are being explored. Our goal was to identify beneficial probiotic strains that would antagonize these fungal and bacterial pathogens that are elevated in the inflamed gut, and which also have antibiofilm activity. Fungus-bacterium correlation analysis allowed us to identify candidate probiotic species that can antagonize microbial pathogens, which we subsequently incorporated into a novel probiotic formulation. Amylase, which is known to have some antibiofilm activity, was also added to the probiotic mixture. This novel probiotic may have utility for the management of inflammatory bowel diseases by disrupting polymicrobial biofilm formation.

scholarly journals csrR, a Paralog and Direct Target of CsrA, Promotes Legionella pneumophila Resilience in Water

mBio ◽  
2015 ◽  
Vol 6 (3) ◽  
Author(s):  
Zachary D. Abbott ◽  
Helen Yakhnin ◽  
Paul Babitzke ◽  
Michele S. Swanson
Keyword(s):  
Legionella Pneumophila ◽  
Tap Water ◽  
Bacterial Species ◽  
Regulatory Protein ◽  
Opportunistic Pathogen ◽  
Water Systems ◽  
Phenotypic Analysis ◽  
Term Survival ◽  
Content Type

ABSTRACTCritical to microbial versatility is the capacity to express the cohort of genes that increase fitness in different environments.Legionella pneumophilaoccupies extensive ecological space that includes diverse protists, pond water, engineered water systems, and mammalian lung macrophages. One mechanism that equips this opportunistic pathogen to adapt to fluctuating conditions is a switch between replicative and transmissive cell types that is controlled by the broadly conserved regulatory protein CsrA. A striking feature of the legionellae surveyed is that each of 14 strains encodes 4 to 7csrA-like genes, candidate regulators of distinct fitness traits. Here we focus on the onecsrAparalog (lpg1593) that, like the canonicalcsrA, is conserved in all 14 strains surveyed. Phenotypic analysis revealed that long-term survival in tap water is promoted by thelpg1593locus, which we namecsrR(for “CsrA-similar protein forresilience”). As predicted by its GGA motif,csrRmRNA was bound directly by the canonical CsrA protein, as judged by electromobility shift and RNA-footprinting assays. Furthermore, CsrA repressed translation ofcsrRmRNAin vivo, as determined by analysis ofcsrR-gfpreporters,csrRmRNA stability in the presence and absence ofcsrAexpression, and mutation of the CsrA binding site identified on thecsrRmRNA. Thus, CsrA not only governs the transition from replication to transmission but also represses translation of its paralogcsrRwhen nutrients are available. We propose that, during prolonged starvation, relief of CsrA repression permits CsrR protein to coordinateL. pneumophila's switch to a cell type that is resilient in water supplies.IMPORTANCEPersistence ofL. pneumophilain water systems is a public health risk, and yet there is little understanding of the genetic determinants that equip this opportunistic pathogen to adapt to and survive in natural or engineered water systems. A potent regulator of this pathogen's intracellular life cycle is CsrA, a protein widely distributed among bacterial species that is understood quite well. Our finding that every sequencedL. pneumophilastrain carries severalcsrAparalogs—including two common to all isolates—indicates that the legionellae exploit CsrA regulatory switches for multiple purposes. Our discovery that one paralog, CsrR, is a target of CsrA that enhances survival in water is an important step toward understanding colonization of the engineered environment by pathogenicL. pneumophila.

scholarly journals A Rhizobiales-Specific Unipolar Polysaccharide Adhesin Contributes to Rhodopseudomonas palustris Biofilm Formation across Diverse Photoheterotrophic Conditions

2016 ◽  
Vol 83 (4) ◽  
Author(s):  
Ryan K. Fritts ◽  
Breah LaSarre ◽  
Ari M. Stoner ◽  
Amanda L. Posto ◽  
James B. McKinlay
Keyword(s):  
Biofilm Formation ◽  
Bacterial Species ◽  
Rhodopseudomonas Palustris ◽  
Gene Clusters ◽  
Growth Conditions ◽  
Organic Substrates ◽  
Biosynthesis Gene Cluster ◽  
Surface Attachment ◽  
Content Type ◽  
Animal Pathogens

ABSTRACT Bacteria predominantly exist as members of surfaced-attached communities known as biofilms. Many bacterial species initiate biofilms and adhere to each other using cell surface adhesins. This is the case for numerous ecologically diverse Alphaprotebacteria, which use polar exopolysaccharide adhesins for cell-cell adhesion and surface attachment. Here, we show that Rhodopseudomonas palustris, a metabolically versatile member of the alphaproteobacterial order Rhizobiales, contains a functional unipolar polysaccharide (UPP) biosynthesis gene cluster. Deletion of genes predicted to be critical for UPP biosynthesis and export abolished UPP production. We also found that R. palustris uses UPP to mediate biofilm formation across diverse photoheterotrophic growth conditions, wherein light and organic substrates are used to support growth. However, UPP was less important for biofilm formation during photoautotrophy, where light and CO2 support growth, and during aerobic respiration with organic compounds. Expanding our analysis beyond R. palustris, we examined the phylogenetic distribution and genomic organization of UPP gene clusters among Rhizobiales species that inhabit diverse niches. Our analysis suggests that UPP is a conserved ancestral trait of the Rhizobiales but that it has been independently lost multiple times during the evolution of this clade, twice coinciding with adaptation to intracellular lifestyles within animal hosts. IMPORTANCE Bacteria are ubiquitously found as surface-attached communities and cellular aggregates in nature. Here, we address how bacterial adhesion is coordinated in response to diverse environments using two complementary approaches. First, we examined how Rhodopseudomonas palustris, one of the most metabolically versatile organisms ever described, varies its adhesion to surfaces in response to different environmental conditions. We identified critical genes for the production of a unipolar polysaccharide (UPP) and showed that UPP is important for adhesion when light and organic substrates are used for growth. Looking beyond R. palustris, we performed the most comprehensive survey to date on the conservation of UPP biosynthesis genes among a group of closely related bacteria that occupy diverse niches. Our findings suggest that UPP is important for free-living and plant-associated lifestyles but dispensable for animal pathogens. Additionally, we propose guidelines for classifying the adhesins produced by various Alphaprotebacteria, facilitating future functional and comparative studies.

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