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Liu S, Gunawan C, Barraud N, Rice SA, Harry EJ, Amal R. Understanding, Monitoring, and Controlling Biofilm Growth in Drinking Water Distribution Systems. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:8954-8976. [PMID: 27479445 DOI: 10.1021/acs.est.6b00835] [Citation(s) in RCA: 190] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In drinking water distribution systems (DWDS), biofilms are the predominant mode of microbial growth, with the presence of extracellular polymeric substance (EPS) protecting the biomass from environmental and shear stresses. Biofilm formation poses a significant problem to the drinking water industry as a potential source of bacterial contamination, including pathogens, and, in many cases, also affecting the taste and odor of drinking water and promoting the corrosion of pipes. This article critically reviews important research findings on biofilm growth in DWDS, examining the factors affecting their formation and characteristics as well as the various technologies to characterize and monitor and, ultimately, to control their growth. Research indicates that temperature fluctuations potentially affect not only the initial bacteria-to-surface attachment but also the growth rates of biofilms. For the latter, the effect is unique for each type of biofilm-forming bacteria; ammonia-oxidizing bacteria, for example, grow more-developed biofilms at a typical summer temperature of 22 °C compared to 12 °C in fall, and the opposite occurs for the pathogenic Vibrio cholerae. Recent investigations have found the formation of thinner yet denser biofilms under high and turbulent flow regimes of drinking water, in comparison to the more porous and loosely attached biofilms at low flow rates. Furthermore, in addition to the rather well-known tendency of significant biofilm growth on corrosion-prone metal pipes, research efforts also found leaching of growth-promoting organic compounds from the increasingly popular use of polymer-based pipes. Knowledge of the unique microbial members of drinking water biofilms and, importantly, the influence of water characteristics and operational conditions on their growth can be applied to optimize various operational parameters to minimize biofilm accumulation. More-detailed characterizations of the biofilm population size and structure are now feasible with fluorescence microscopy (epifluorescence and CLSM imaging with DNA, RNA, EPS, and protein and lipid stains) and electron microscopy imaging (ESEM). Importantly, thorough identification of microbial fingerprints in drinking water biofilms is achievable with DNA sequencing techniques (the 16S rRNA gene-based identification), which have revealed a prevalence of previously undetected bacterial members. Technologies are now moving toward in situ monitoring of biomass growth in distribution networks, including the development of optical fibers capable of differentiating biomass from chemical deposits. Taken together, management of biofilm growth in water distribution systems requires an integrated approach, starting from the treatment of water prior to entering the networks to the potential implementation of "biofilm-limiting" operational conditions and, finally, ending with the careful selection of available technologies for biofilm monitoring and control. For the latter, conventional practices, including chlorine-chloramine disinfection, flushing of DWDS, nutrient removal, and emerging technologies are discussed with their associated challenges.
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Affiliation(s)
| | - Cindy Gunawan
- ithree institute, University of Technology Sydney , Sydney, NSW 2007, Australia
| | - Nicolas Barraud
- Department of Microbiology, Genetics of Biofilms Unit, Institut Pasteur , Paris 75015, France
| | - Scott A Rice
- The Singapore Centre for Environmental Life Sciences Engineering and School of Biological Sciences, Nanyang Technological University , 639798, Singapore
| | - Elizabeth J Harry
- ithree institute, University of Technology Sydney , Sydney, NSW 2007, Australia
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Lawrence JR, Swerhone GDW, Kuhlicke U, Neu TR. In situevidence for metabolic and chemical microdomains in the structured polymer matrix of bacterial microcolonies. FEMS Microbiol Ecol 2016; 92:fiw183. [DOI: 10.1093/femsec/fiw183] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/22/2016] [Indexed: 11/13/2022] Open
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Roth-Schulze AJ, Zozaya-Valdés E, Steinberg PD, Thomas T. Partitioning of functional and taxonomic diversity in surface-associated microbial communities. Environ Microbiol 2016; 18:4391-4402. [PMID: 27062175 DOI: 10.1111/1462-2920.13325] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 03/29/2016] [Accepted: 03/31/2016] [Indexed: 12/14/2022]
Abstract
Surfaces, including those submerged in the marine environment, are subjected to constant interactions and colonisation by surrounding microorganisms. The principles that determine the assembly of those epibiotic communities are however poorly understood. In this study, we employed a hierarchical design to assess the functionality and diversity of microbial communities on different types of host surfaces (e.g. macroalgae, seagrasses). We found that taxonomic diversity was unique to each type of host, but that the majority of functions (> 95%) could be found in any given surface community, suggesting a high degree of functional redundancy. However, some community functions were enriched on certain surfaces and were related to host-specific properties (e.g. the degradation of specific polysaccharides). Together these observations support a model, whereby communities on surfaces are assembled from guilds of microorganisms with a functionality that is partitioned into general properties for a surface-associated life-style, but also specific features that mediate host-specificity.
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Affiliation(s)
- Alexandra J Roth-Schulze
- Centre for Marine Bio-Innovation, School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - Enrique Zozaya-Valdés
- Centre for Marine Bio-Innovation, School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - Peter D Steinberg
- Centre for Marine Bio-Innovation, School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, 2052, Australia.,Sydney Institute of Marine Science, 2 Chowder Bay Rd., Mosman, NSW, 2088, Australia
| | - Torsten Thomas
- Centre for Marine Bio-Innovation, School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, 2052, Australia
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Dapunt U, Hänsch GM, Arciola CR. Innate Immune Response in Implant-Associated Infections: Neutrophils against Biofilms. MATERIALS 2016; 9:ma9050387. [PMID: 28773509 PMCID: PMC5503022 DOI: 10.3390/ma9050387] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/20/2016] [Revised: 04/28/2016] [Accepted: 05/06/2016] [Indexed: 12/15/2022]
Abstract
Biofilm has been recognized as a well-protected form of living for bacteria, contributing to bacterial pathogenicity, particularly for opportunistic species. Biofilm-associated infections are marked by their persistence. Extensive research has been devoted to the formation and composition of biofilms. The immune response against biofilms remains rather unexplored, but there is the notion that bacteria within a biofilm are protected from host defences. Here we glance at the mechanisms by which neutrophils recognize and face biofilms in implant infections and discuss the implications of this interplay, as well as speculate on its significance.
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Affiliation(s)
- Ulrike Dapunt
- Center for Orthopaedics, Trauma Surgery and Spinal Cord Injury, Heidelberg University Hospital, Schlierbacher Landstrasse 200a, Heidelberg 69118, Germany.
| | - Gertrud Maria Hänsch
- Institute for Immunology, Heidelberg University, Im Neuenheimer Feld 305, Heidelberg 69120, Germany.
| | - Carla Renata Arciola
- Research Unit on Implant Infections, Rizzoli Orthopaedic Institute, Bologna 40136, Italy.
- Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Bologna 40126, Italy.
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General Overview on Nontuberculous Mycobacteria, Biofilms, and Human Infection. J Pathog 2015; 2015:809014. [PMID: 26618006 PMCID: PMC4649093 DOI: 10.1155/2015/809014] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 10/15/2015] [Indexed: 11/17/2022] Open
Abstract
Nontuberculous mycobacteria (NTM) are emergent pathogens whose importance in human health has been growing. After being regarded mainly as etiological agents of opportunist infections in HIV patients, they have also been recognized as etiological agents of several infections on immune-competent individuals and healthcare-associated infections. The environmental nature of NTM and their ability to assemble biofilms on different surfaces play a key role in their pathogenesis. Here, we review the clinical manifestations attributed to NTM giving particular importance to the role played by biofilm assembly.
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56
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Effects of elevated intracellular cyclic di-GMP levels on biofilm formation and transcription profiles of Vibrio vulnificus. Food Sci Biotechnol 2015. [DOI: 10.1007/s10068-015-0100-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Rillig MC, Rolff J, Tietjen B, Wehner J, Andrade-Linares DR. Community priming--effects of sequential stressors on microbial assemblages. FEMS Microbiol Ecol 2015; 91:fiv040. [PMID: 25873462 DOI: 10.1093/femsec/fiv040] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/31/2015] [Indexed: 11/12/2022] Open
Abstract
Microbes in nature are exposed to complex environmental stressors which challenge their functioning or survival. Priming is the improved reaction of an organism to an environmental stressor following a preceding, often milder stress event. This phenomenon, also known as cross-protection, predictive response strategy or acquired stress resistance, is becoming an increasingly well-established research topic in microbiology, which has so far been examined from the perspective of a single organism or population. However, microbes in nature occur as part of communities; thus it is timely to highlight the need to also include this level beyond the individual species in studies of priming effects. We here introduce a conceptual framework for such studies at the level of the microbial assemblage and also chart a way forward for empirical and theoretical study. We illustrate some of the elements of our framework with a simple simulation model. Given the dynamic habitat of many microbes, incorporating priming is important for a more complete understanding of microbial community responses to stress.
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Affiliation(s)
- Matthias C Rillig
- Freie Universität Berlin, Institut für Biologie, Plant Ecology, D-14195 Berlin, Germany Berlin-Brandenburg Institute of Advanced Biodiversity Research (BBIB), D-14195 Berlin, Germany
| | - Jens Rolff
- Freie Universität Berlin, Institut für Biologie, Evolutionary Biology, D-14195 Berlin, Germany Berlin-Brandenburg Institute of Advanced Biodiversity Research (BBIB), D-14195 Berlin, Germany
| | - Britta Tietjen
- Freie Universität Berlin, Institut für Biologie, Biodiversity/Ecological Modeling, D-14195 Berlin, Germany Berlin-Brandenburg Institute of Advanced Biodiversity Research (BBIB), D-14195 Berlin, Germany
| | - Jeannine Wehner
- Freie Universität Berlin, Institut für Biologie, Plant Ecology, D-14195 Berlin, Germany Berlin-Brandenburg Institute of Advanced Biodiversity Research (BBIB), D-14195 Berlin, Germany
| | - Diana R Andrade-Linares
- Freie Universität Berlin, Institut für Biologie, Plant Ecology, D-14195 Berlin, Germany Berlin-Brandenburg Institute of Advanced Biodiversity Research (BBIB), D-14195 Berlin, Germany
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Hutcherson JA, Scott DA, Bagaitkar J. Scratching the surface - tobacco-induced bacterial biofilms. Tob Induc Dis 2015; 13:1. [PMID: 25670926 PMCID: PMC4323140 DOI: 10.1186/s12971-014-0026-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Accepted: 12/08/2014] [Indexed: 11/10/2022] Open
Abstract
Individual environmental factors, such as iron, temperature and oxygen, are known to have a profound effect on bacterial phenotype. Therefore, it is surprising so little known is about the influence of chemically complex cigarette smoke on bacterial physiology. Recent evidence has demonstrated that tobacco smoke and components alter the bacterial surface and promote biofilm formation in several important human pathogens, including Staphylococcus aureus, Streptococcus mutans, Klebsiella pneumonia, Porphyromonas gingivalis and Pseudomonas aeruginosa. The mechanisms underlying this phenomenon and the relevance to increased susceptibility to infectious disease in smokers and to treatment are reviewed.
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Affiliation(s)
- Justin A Hutcherson
- Departments of Microbiology and Immunology, University of Louisville, Louisville, USA
| | - David A Scott
- Oral Immunology and Infectious Diseases, University of Louisville, 501 South Preston Street, Louisville, KY 40292 USA
| | - Juhi Bagaitkar
- Pediatrics, Washington University School of Medicine, Saint Louis, MO USA
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Sharma BK, Saha A, Rahaman L, Bhattacharjee S, Tribedi P. Silver Inhibits the Biofilm Formation of <i>Pseudomonas aeruginosa</i>. ACTA ACUST UNITED AC 2015. [DOI: 10.4236/aim.2015.510070] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Remuzgo-Martínez S, Lázaro-Díez M, Padilla D, Vega B, El Aamri F, Icardo JM, Acosta F, Ramos-Vivas J. New aspects in the biology of Photobacterium damselae subsp. piscicida: pili, motility and adherence to solid surfaces. Vet Microbiol 2014; 174:247-54. [PMID: 25263496 DOI: 10.1016/j.vetmic.2014.08.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2014] [Revised: 08/01/2014] [Accepted: 08/03/2014] [Indexed: 10/24/2022]
Abstract
We describe for the first time the presence of pilus-like structures on the surface of Photobacterium damselae subsp. piscicida (Phdp). The hint to this discovery was the ability of one strain to hemagglutinate human erythrocytes. Further analysis of several Phdp strains ultrastructure by electron microscopy revealed the presence of long, thin fibers, similar to pili of other Gram-negative bacteria. These appendages were also observed and photographed by scanning, transmission electron microscopy and immunofluorescence. Although this fish pathogen has been described as non-motile, all strains tested exhibit twitching motility, a flagella-independent type IV-dependent form of bacterial translocation over surfaces. As far as we are aware, the movement of Phdp bacteria on semi-solid or solid surfaces has not been described previously. Moreover, we speculate that Phdp twitching motility may be involved in biofilm formation. Microscopic examination of Phdp biofilms by microscopy revealed that Phdp biofilm architecture display extensive cellular chaining and also bacterial mortality during biofilm formation in vitro. Based on our results, standardized analyses of Phdp surface appendages, biofilms, motility and their impact on Phdp survival, ecology and pathobiology are now feasible.
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Affiliation(s)
- Sara Remuzgo-Martínez
- Servicio de Microbiología, Hospital Universitario Marqués de Valdecilla, Instituto de Investigación Marqués de Valdecilla IDIVAL, Santander, Cantabria, Spain
| | - María Lázaro-Díez
- Servicio de Microbiología, Hospital Universitario Marqués de Valdecilla, Instituto de Investigación Marqués de Valdecilla IDIVAL, Santander, Cantabria, Spain
| | - Daniel Padilla
- Instituto Universitario de Sanidad Animal, Universidad de Las Palmas de Gran Canaria, Arucas, Spain
| | - Belinda Vega
- Instituto Universitario de Sanidad Animal, Universidad de Las Palmas de Gran Canaria, Arucas, Spain
| | - Fátima El Aamri
- Instituto Universitario de Sanidad Animal, Universidad de Las Palmas de Gran Canaria, Arucas, Spain
| | - José Manuel Icardo
- Departamento de Anatomía y Biología Celular, Universidad de Cantabria, Santander, Cantabria, Spain
| | - Félix Acosta
- Instituto Universitario de Sanidad Animal, Universidad de Las Palmas de Gran Canaria, Arucas, Spain
| | - José Ramos-Vivas
- Servicio de Microbiología, Hospital Universitario Marqués de Valdecilla, Instituto de Investigación Marqués de Valdecilla IDIVAL, Santander, Cantabria, Spain.
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Isolation and molecular characterization of biofouling bacteria and profiling of quorum sensing signal molecules from membrane bioreactor activated sludge. Int J Mol Sci 2014; 15:2255-73. [PMID: 24499972 PMCID: PMC3958849 DOI: 10.3390/ijms15022255] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 01/17/2014] [Accepted: 01/23/2014] [Indexed: 02/02/2023] Open
Abstract
The formation of biofilm in a membrane bioreactor depends on the production of various signaling molecules like N-acyl homoserine lactones (AHLs). In the present study, a total of 200 bacterial strains were isolated from membrane bioreactor activated sludge and screened for AHLs production using two biosensor systems, Chromobacterium violaceum CV026 and Agrobacterium tumefaciens A136. A correlation between AHLs production and biofilm formation has been made among screened AHLs producing strains. The 16S rRNA gene sequence analysis revealed the dominance of Aeromonas and Enterobacter sp. in AHLs production; however few a species of Serratia, Leclercia, Pseudomonas, Klebsiella, Raoultella and Citrobacter were also identified. The chromatographic characterization of sludge extract showed the presence of a broad range of quorum sensing signal molecules. Further identification of sludge AHLs by thin layer chromatography bioassay and high performance liquid chromatography confirms the presence of C4-HSL, C6-HSL, C8-HSL, 3-oxo-C8-HSL, C10-HSL, C12-HSL, 3-oxo-C12-HSL and C14-HSL. The occurrence of AHLs in sludge extract and dominance of Aeromonas and Enterobacter sp. in activated sludge suggests the key role of these bacterial strains in AHLs production and thereby membrane fouling.
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Wang M, Hashimoto M, Hashidoko Y. Repression of tropolone production and induction of a Burkholderia plantarii pseudo-biofilm by carot-4-en-9,10-diol, a cell-to-cell signaling disrupter produced by Trichoderma virens. PLoS One 2013; 8:e78024. [PMID: 24223754 PMCID: PMC3817171 DOI: 10.1371/journal.pone.0078024] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 09/09/2013] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The tropolone-tolerant Trichoderma virens PS1-7 is a biocontrol agent against Burkholderia plantarii, causative of rice seedling blight. When exposed to catechol, this fungus dose-dependently produced carot-4-en-9,10-diol, a sesquiterpene-type autoregulatory signal molecule that promotes self-conidiation of T. virens PS1-7 mycelia. It was, however, uncertain why T. virens PS1-7 attenuates the symptom development of the rice seedlings infested with B. plantarii. METHODOLOGY/PRINCIPAL FINDINGS To reveal the antagonism by T. virens PS1-7 against B. plantarii leading to repression of tropolone production in a coculture system, bioassay-guided screening for active compounds from a 3-d culture of T. virens PS1-7 was conducted. As a result, carot-4-en-9,10-diol was identified and found to repress tropolone production of B. plantarii from 10 to 200 µM in a dose-dependent manner as well as attenuate virulence of B. plantarii on rice seedlings. Quantitative RT-PCR analysis revealed that transcriptional suppression of N-acyl-L-homoserine lactone synthase plaI in B. plantarii was the main mode of action by which carot-4-en-9,10-diol mediated the quorum quenching responsible for repression of tropolone production. In addition, the unique response of B. plantarii to carot-4-en-9,10-diol in the biofilm formed in the static culture system was also found. Although the initial stage of B. plantarii biofilm formation was induced by both tropolone and carot-4-en-9,10-diol, it was induced in different states. Moreover, the B. plantarii biofilm that was induced by carot-4-en-9,10-diol at the late stage showed defects not only in matrix structure but also cell viability. CONCLUSIONS/SIGNIFICANCE Our findings demonstrate that carot-4-en-9,10-diol released by T. virens PS1-7 acts as an interkingdom cell-to-cell signaling molecule against B. plantarii to repress tropolone production and induces pseudo-biofilm to the cells. This observation also led to another discovery that tropolone is an autoregulatory cell-to-cell signaling molecule of B. plantarii that induces a functional biofilm other than a simple B. plantarii virulence factor.
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Affiliation(s)
- Mengcen Wang
- Graduate School of Agriculture & Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan
| | - Makoto Hashimoto
- Graduate School of Agriculture & Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan
| | - Yasuyuki Hashidoko
- Graduate School of Agriculture & Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan
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Kerekes EB, Deák É, Takó M, Tserennadmid R, Petkovits T, Vágvölgyi C, Krisch J. Anti-biofilm forming and anti-quorum sensing activity of selected essential oils and their main components on food-related micro-organisms. J Appl Microbiol 2013; 115:933-42. [DOI: 10.1111/jam.12289] [Citation(s) in RCA: 156] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Revised: 06/03/2013] [Accepted: 06/16/2013] [Indexed: 11/26/2022]
Affiliation(s)
- E.-B. Kerekes
- Department of Microbiology; Faculty of Science and Informatics; University of Szeged; Szeged Hungary
| | - É. Deák
- Institute of Food Engineering; Faculty of Engineering; University of Szeged; Szeged Hungary
| | - M. Takó
- Department of Microbiology; Faculty of Science and Informatics; University of Szeged; Szeged Hungary
| | - R. Tserennadmid
- Institute of Biology; Mongolian Academy of Sciences; Ulaanbaatar Mongolia
| | - T. Petkovits
- Department of Microbiology; Faculty of Science and Informatics; University of Szeged; Szeged Hungary
| | - C. Vágvölgyi
- Department of Microbiology; Faculty of Science and Informatics; University of Szeged; Szeged Hungary
| | - J. Krisch
- Institute of Food Engineering; Faculty of Engineering; University of Szeged; Szeged Hungary
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Stiegelmeyer SM, Giddings MC. Agent-based modeling of competence phenotype switching in Bacillus subtilis. Theor Biol Med Model 2013; 10:23. [PMID: 23551850 PMCID: PMC3648451 DOI: 10.1186/1742-4682-10-23] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Accepted: 03/21/2013] [Indexed: 11/17/2022] Open
Abstract
Background It is a fascinating phenomenon that in genetically identical bacteria populations of Bacillus subtilis, a distinct DNA uptake phenotype called the competence phenotype may emerge in 10–20% of the population. Many aspects of the phenomenon are believed to be due to the variable expression of critical genes: a stochastic occurrence termed “noise” which has made the phenomenon difficult to examine directly by lab experimentation. Methods To capture and model noise in this system and further understand the emergence of competence both at the intracellular and culture levels in B. subtilis, we developed a novel multi-scale, agent-based model. At the intracellular level, our model recreates the regulatory network involved in the competence phenotype. At the culture level, we simulated growth conditions, with our multi-scale model providing feedback between the two levels. Results Our model predicted three potential sources of genetic “noise”. First, the random spatial arrangement of molecules may influence the manifestation of the competence phenotype. In addition, the evidence suggests that there may be a type of epigenetic heritability to the emergence of competence, influenced by the molecular concentrations of key competence molecules inherited through cell division. Finally, the emergence of competence during the stationary phase may in part be due to the dilution effect of cell division upon protein concentrations. Conclusions The competence phenotype was easily translated into an agent-based model – one with the ability to illuminate complex cell behavior. Models such as the one described in this paper can simulate cell behavior that is otherwise unobservable in vivo, highlighting their potential usefulness as research tools.
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Affiliation(s)
- Suzy M Stiegelmeyer
- Syngenta Biotechnology, Inc., 3054 Cornwallis Rd., Research Triangle Park, NC 27709, USA.
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Sha Q, Vattem DA, Forstner MRJ, Hahn D. Quantifying Salmonella population dynamics in water and biofilms. MICROBIAL ECOLOGY 2013; 65:60-67. [PMID: 22890729 DOI: 10.1007/s00248-012-0106-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Accepted: 07/24/2012] [Indexed: 06/01/2023]
Abstract
Members of the bacterial genus Salmonella are recognized worldwide as major zoonotic pathogens often found to persist in non-enteric environments including heterogeneous aquatic biofilms. In this study, Salmonella isolates that had been detected repeatedly over time in aquatic biofilms at different sites in Spring Lake, San Marcos, Texas, were identified as serovars Give, Thompson, Newport and -:z10:z39. Pathogenicity results from feeding studies with the nematode Caenorhabditis elegans as host confirmed that these strains were pathogenic, with Salmonella-fed C. elegans dying faster (mean survival time between 3 and 4 days) than controls, i.e., Escherichia coli-fed C. elegans (mean survival time of 9.5 days). Cells of these isolates inoculated into water at a density of up to 10(6) ml(-1) water declined numerically by 3 orders of magnitude within 2 days, reaching the detection limit of our quantitative polymerase chain reaction (qPCR)-based quantification technique (i.e., 10(3) cells ml(-1)). Similar patterns were obtained for cells in heterogeneous aquatic biofilms developed on tiles and originally free of Salmonella that were kept in the inoculated water. Cell numbers increased during the first days to more than 10(7) cells cm(-2), and then declined over time. Ten-fold higher cell numbers of Salmonella inoculated into water or into biofilm resulted in similar patterns of population dynamics, though cells in biofilms remained detectable with numbers around 10(4) cells cm(-2) after 4 weeks. Independent of detectability by qPCR, samples of all treatments harbored viable salmonellae that resembled the inoculated isolates after 4 weeks of incubation. These results demonstrate that pathogenic salmonellae were isolated from heterogeneous aquatic biofilms and that they could persist and stay viable in such biofilms in high numbers for some time.
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Affiliation(s)
- Qiong Sha
- Department of Biology, Texas State University, 601 University Drive, San Marcos, TX 78666, USA
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Siqueira VM, Oliveira HMB, Santos C, Paterson RRM, Gusmão NB, Lima N. Biofilms from a Brazilian water distribution system include filamentous fungi. Can J Microbiol 2012; 59:183-8. [PMID: 23540336 DOI: 10.1139/cjm-2012-0529] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Filamentous fungi in drinking water can block water pipes, can cause organoleptic biodeterioration, and are a source of pathogens. There are increasing reports of the involvement of the organisms in biofilms. This present study describes a sampling device that can be inserted directly into pipes within water distribution systems, allowing biofilm formation in situ. Calcofluor White M2R staining and fluorescent in situ hybridization with morphological analyses using epifluorescent microscopy were used to analyse biofilms for filamentous fungi, permitting direct observation of the fungi. DAPI (4',6-diamidino-2-phenylindole) was applied to detect bacteria. Filamentous fungi were detected in biofilms after 6 months on coupons exposed to raw water, decanted water and at the entrance of the water distribution system. Algae, yeast, and bacteria were also observed. The role of filamentous fungi requires further investigations.
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Affiliation(s)
- V M Siqueira
- Institute for Biotechnology and Bioengineering (IBB), Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
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Abstract
Bacteria living as biofilms have been recognised as the ultimate cause of persistent and destructive inflammatory processes. Biofilm formation is a well-organised, genetically-driven process, which is well characterised for numerous bacteria species. In contrast, the host response to bacterial biofilms is less well analysed, and there is the general believe that bacteria in biofilms escape recognition or eradication by the immune defence. In this review the host response to bacterial biofilms is discussed with particular focus on the role of neutrophils because these phagocytic cells are the first to infiltrate areas of bacterial infection, and because neutrophils are equipped with a wide arsenal of bactericidal and toxic entities. I come to the conclusion that bacterial biofilms are not inherently protected against the attack by neutrophils, but that control of biofilm formation is possible depending on a timely and sufficient host response.
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Iwashkiw JA, Seper A, Weber BS, Scott NE, Vinogradov E, Stratilo C, Reiz B, Cordwell SJ, Whittal R, Schild S, Feldman MF. Identification of a general O-linked protein glycosylation system in Acinetobacter baumannii and its role in virulence and biofilm formation. PLoS Pathog 2012; 8:e1002758. [PMID: 22685409 PMCID: PMC3369928 DOI: 10.1371/journal.ppat.1002758] [Citation(s) in RCA: 154] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Accepted: 05/01/2012] [Indexed: 01/12/2023] Open
Abstract
Acinetobacter baumannii is an emerging cause of nosocomial infections. The isolation of strains resistant to multiple antibiotics is increasing at alarming rates. Although A. baumannii is considered as one of the more threatening “superbugs” for our healthcare system, little is known about the factors contributing to its pathogenesis. In this work we show that A. baumannii ATCC 17978 possesses an O-glycosylation system responsible for the glycosylation of multiple proteins. 2D-DIGE and mass spectrometry methods identified seven A. baumannii glycoproteins, of yet unknown function. The glycan structure was determined using a combination of MS and NMR techniques and consists of a branched pentasaccharide containing N-acetylgalactosamine, glucose, galactose, N-acetylglucosamine, and a derivative of glucuronic acid. A glycosylation deficient strain was generated by homologous recombination. This strain did not show any growth defects, but exhibited a severely diminished capacity to generate biofilms. Disruption of the glycosylation machinery also resulted in reduced virulence in two infection models, the amoebae Dictyostelium discoideum and the larvae of the insect Galleria mellonella, and reduced in vivo fitness in a mouse model of peritoneal sepsis. Despite A. baumannii genome plasticity, the O-glycosylation machinery appears to be present in all clinical isolates tested as well as in all of the genomes sequenced. This suggests the existence of a strong evolutionary pressure to retain this system. These results together indicate that O-glycosylation in A. baumannii is required for full virulence and therefore represents a novel target for the development of new antibiotics. Multidrug resistant (MDR) Acinetobacter baumannii strains are an increasing cause of nosocomial infections worldwide. Due to the remarkable ability of A. baumannii to gain resistance to antibiotics, this bacterium is now considered to be a “superbug”. A. baumannii strains resistant to all clinically relevant antibiotics known have also been isolated. Although MDR A. baumannii continues to disseminate globally, very little is known about its pathogenesis mechanisms. Our experiments revealed that A. baumannii ATCC 17978 has a functional O-linked protein glycosylation system, which seems to be present in all strains of A. baumannii sequenced to date and several clinical isolates. We identified seven glycoproteins and elucidated the structure of the glycan moiety. A glycosylation-deficient strain was generated. This strain produced severely reduced biofilms, and exhibited attenuated virulence in amoeba, insect, and murine models. These experiments suggest that glycosylation may play an important role in virulence and may lay the foundation for new drug discovery strategies that could stop the dissemination of this emerging human pathogen, which has become a major threat for healthcare systems.
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Affiliation(s)
- Jeremy A. Iwashkiw
- Alberta Glycomics Centre, Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Andrea Seper
- Institut fuer Molekulare Biowissenschaften, Karl-Franzens-Universitaet Graz, Graz, Austria
| | - Brent S. Weber
- Alberta Glycomics Centre, Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Nichollas E. Scott
- Alberta Glycomics Centre, Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
- School of Molecular and Microbial Biosciences, University of Sydney, Sydney, New South Wales, Australia
| | - Evgeny Vinogradov
- Institute for Biological Sciences, National Research Council, Ottawa, Ontario, Canada
| | - Chad Stratilo
- Defence Research and Development Canada Suffield, Medicine Hat, Alberta, Canada
| | - Bela Reiz
- Alberta Glycomics Centre, Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Stuart J. Cordwell
- School of Molecular and Microbial Biosciences, University of Sydney, Sydney, New South Wales, Australia
| | - Randy Whittal
- Alberta Glycomics Centre, Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Stefan Schild
- Institut fuer Molekulare Biowissenschaften, Karl-Franzens-Universitaet Graz, Graz, Austria
| | - Mario F. Feldman
- Alberta Glycomics Centre, Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
- * E-mail:
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70
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Kang J, Kim T, Tak Y, Lee JH, Yoon J. Cyclic voltammetry for monitoring bacterial attachment and biofilm formation. J IND ENG CHEM 2012. [DOI: 10.1016/j.jiec.2011.10.002] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Nievas F, Bogino P, Sorroche F, Giordano W. Detection, characterization, and biological effect of quorum-sensing signaling molecules in peanut-nodulating bradyrhizobia. SENSORS 2012; 12:2851-73. [PMID: 22736981 PMCID: PMC3376631 DOI: 10.3390/s120302851] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/11/2012] [Revised: 02/23/2012] [Accepted: 02/23/2012] [Indexed: 11/16/2022]
Abstract
Bacteria of the genus Bradyrhizobium are able to establish a symbiotic relationship with peanut (Arachis hypogaea) root cells and to fix atmospheric nitrogen by converting it to nitrogenous compounds. Quorum sensing (QS) is a cell-cell communication mechanism employed by a variety of bacterial species to coordinate behavior at a community level through regulation of gene expression. The QS process depends on bacterial production of various signaling molecules, among which the N-acylhomoserine lactones (AHLs) are most commonly used by Gram-negative bacteria. Some previous reports have shown the production of QS signaling molecules by various rhizobia, but little is known regarding mechanisms of communication among peanut-nodulating strains. The aims of this study were to identify and characterize QS signals produced by peanut-nodulating bradyrhizobial strains and to evaluate their effects on processes related to cell interaction. Detection of AHLs in 53 rhizobial strains was performed using the biosensor strains Agrobacterium tumefaciens NTL4 (pZLR4) and Chromobacterium violaceum CV026 for AHLs with long and short acyl chains, respectively. None of the strains screened were found to produce AHLs with short acyl chains, but 14 strains produced AHLs with long acyl chains. These 14 AHL-producing strains were further studied by quantification of β-galactosidase activity levels (AHL-like inducer activity) in NTL4 (pZLR4). Strains displaying moderate to high levels of AHL-like inducer activity were subjected to chemical identification of signaling molecules by high-performance liquid chromatography coupled to mass spectrometry (LC-MS/MS). For each AHL-producing strain, we found at least four different AHLs, corresponding to N-hexanoyl-dl-homoserine lactone (C6), N-(3-oxodecanoyl)-l-homoserine lactone (3OC10), N-(3-oxododecanoyl)-l-homoserine lactone (3OC12), and N-(3-oxotetradecanoyl)-l-homoserine lactone (3OC14). Biological roles of 3OC10, 3OC12, and 3OC14 AHLs were evaluated in both AHL-producing and -non-producing peanut-nodulating strains. Bacterial processes related to survival and nodulation, including motility, biofilm formation, and cell aggregation, were affected or modified by the exogenous addition of increasing concentrations of synthetic AHLs. Our results clearly demonstrate the existence of cell communication mechanisms among bradyrhizobial strains symbiotic of peanut. AHLs with long acyl chains appear to be signaling molecules regulating important QS physiological processes in these bacteria.
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Affiliation(s)
- Fiorela Nievas
- Departamento de Biología Molecular, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba, Argentina.
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72
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Valeru SP, Wai SN, Saeed A, Sandström G, Abd H. ToxR of Vibrio cholerae affects biofilm, rugosity and survival with Acanthamoeba castellanii. BMC Res Notes 2012; 5:33. [PMID: 22248371 PMCID: PMC3292481 DOI: 10.1186/1756-0500-5-33] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2011] [Accepted: 01/16/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Vibrio cholerae causes the diarrheal disease cholera and utilizes different survival strategies in aquatic environments. V. cholerae can survive as free-living or in association with zooplankton and can build biofilm and rugose colonies. The bacterium expresses cholera toxin (CT) and toxin-coregulated pilus (TCP) as the main virulence factors. These factors are co-regulated by a transcriptional regulator ToxR, which modulates expression of outer membrane proteins (OmpU) and (OmpT). The aims of this study were to disclose the role of ToxR in expression of OmpU and OmpT, biofilm and rugose colony formation as well as in association with the free-living amoeba Acanthamoeba castellanii at different temperatures. RESULTS The toxR mutant V. cholerae produced OmpT, significant biofilm and rugose colonies compared to the wild type that produced OmpU, decreased biofilm and did not form rugoes colonies at 30°C. Interestingly, neither the wild type nor toxR mutant strain could form rugose colonies in association with the amoebae. However, during the association with the amoebae it was observed that A. castellanii enhanced survival of V. cholerae wild type compared to toxR mutant strain at 37°C. CONCLUSIONS ToxR does seem to play some regulatory role in the OmpT/OmpU expression shift, the changes in biofilm, rugosity and survival with A. castellanii, suggesting a new role for this regulatory protein in the environments.
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Affiliation(s)
- Soni P Valeru
- Karolinska Institute, Department of Laboratory Medicine, Division of Clinical Microbiology, Karolinska University Hospital, Huddinge, SE-141 86, Stockholm, Sweden.
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73
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Hödl I, Hödl J, Wörman A, Singer G, Besemer K, Battin TJ. Voronoi tessellation captures very early clustering of single primary cells as induced by interactions in nascent biofilms. PLoS One 2011; 6:e26368. [PMID: 22028865 PMCID: PMC3196551 DOI: 10.1371/journal.pone.0026368] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2011] [Accepted: 09/25/2011] [Indexed: 11/19/2022] Open
Abstract
Biofilms dominate microbial life in numerous aquatic ecosystems, and in engineered and medical systems, as well. The formation of biofilms is initiated by single primary cells colonizing surfaces from the bulk liquid. The next steps from primary cells towards the first cell clusters as the initial step of biofilm formation remain relatively poorly studied. Clonal growth and random migration of primary cells are traditionally considered as the dominant processes leading to organized microcolonies in laboratory grown monocultures. Using Voronoi tessellation, we show that the spatial distribution of primary cells colonizing initially sterile surfaces from natural streamwater community deviates from uniform randomness already during the very early colonisation. The deviation from uniform randomness increased with colonisation — despite the absence of cell reproduction — and was even more pronounced when the flow of water above biofilms was multidirectional and shear stress elevated. We propose a simple mechanistic model that captures interactions, such as cell-to-cell signalling or chemical surface conditioning, to simulate the observed distribution patterns. Model predictions match empirical observations reasonably well, highlighting the role of biotic interactions even already during very early biofilm formation despite few and distant cells. The transition from single primary cells to clustering accelerated by biotic interactions rather than by reproduction may be particularly advantageous in harsh environments — the rule rather than the exception outside the laboratory.
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Affiliation(s)
- Iris Hödl
- Department of Limnology, University of Vienna, Vienna, Austria
- WasserCluster Lunz GmbH, Lunz am See, Austria
| | | | - Anders Wörman
- Department of Land and Water Resources Engineering, Royal Institute of Technology, Stockholm, Sweden
| | - Gabriel Singer
- Department of Limnology, University of Vienna, Vienna, Austria
- WasserCluster Lunz GmbH, Lunz am See, Austria
| | - Katharina Besemer
- Department of Limnology, University of Vienna, Vienna, Austria
- WasserCluster Lunz GmbH, Lunz am See, Austria
| | - Tom J. Battin
- Department of Limnology, University of Vienna, Vienna, Austria
- WasserCluster Lunz GmbH, Lunz am See, Austria
- * E-mail:
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74
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Habimana O, Guillier L, Kulakauskas S, Briandet R. Spatial competition with Lactococcus lactis in mixed-species continuous-flow biofilms inhibits Listeria monocytogenes growth. BIOFOULING 2011; 27:1065-1072. [PMID: 22043862 DOI: 10.1080/08927014.2011.626124] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Surfaces in industrial settings provide a home for resident biofilms that are likely to interact with the attachment, growth and survival of pathogens such as Listeria monocytogenes. Experimental results have indicated that L. monocytogenes cells were inhibited by the presence of a model resident flora (Lactococcus lactis) in dual-species continuous flow-biofilms, and are spatially restricted to the lower biofilm layers. Using a new, simplified individual-based model (IBM) that simulates bacterial cell growth in a three-dimensional space, the spatial arrangements of the two species were reconstructed and their cell counts successfully predicted. This model showed that the difference in generation times between L. monocytogenes and L. lactis cells during the initial stages of dual-species biofilm formation was probably responsible for the species spatialization observed and the subsequent inhibition of growth of the pathogen.
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75
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Das T, Sharma PK, Krom BP, van der Mei HC, Busscher HJ. Role of eDNA on the adhesion forces between Streptococcus mutans and substratum surfaces: influence of ionic strength and substratum hydrophobicity. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:10113-10118. [PMID: 21740034 DOI: 10.1021/la202013m] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The aim of this study was to investigate the role of extracellular DNA (eDNA) on the adhesion strength of Streptococcus mutans LT11 on substrata with different hydrophobicities at high and low ionic strengths. AFM adhesion forces to a hydrophilic and hydrophobic substratum increased with increasing surface-delay times and ionic strength and were stronger on a hydrophobic than on a hydrophilic substratum. The presence of eDNA on the streptococcal cell surface enhanced its adhesion force to a hydrophobic substratum significantly more than to a hydrophilic substratum, especially after bond maturation. Bond maturation on a hydrophilic substratum was accompanied by an increasing number of minor adhesion peaks, indicating the involvement of acid-base interactions, whereas on the hydrophobic substratum surface the number of minor adhesion peaks remained low. More minor adhesion peaks developed on the hydrophilic substratum at low ionic strength than at high ionic strength. The final rupture distance in retraction force-distance curves was independent of ionic strength on a hydrophilic substratum and increased with increasing surface delay time. On the hydrophobic surface, the final rupture distance did not increase with surface delay time but was significantly smaller at low than at high ionic strength. Final rupture distances were different in presence and absence of eDNA, and the lower values of this difference coincided with the decrease in hydrodynamic radius of the streptococci upon increasing ionic strength, measured using dynamic light scattering. AFM also yielded higher values for the ionic strength induced difference in final rupture distance because in AFM rupture is forced, while in dynamic light scattering differences in radius are only induced by ionic strength differences.
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Affiliation(s)
- Theerthankar Das
- Department of Biomedical Engineering, W.J. Kolff Institute, University Medical Center Groningen and University of Groningen, Antonius Deusinglaan 1, 9713 AV, Groningen, The Netherlands
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76
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Koo H, Xiao J, Klein MI, Jeon JG. Exopolysaccharides produced by Streptococcus mutans glucosyltransferases modulate the establishment of microcolonies within multispecies biofilms. J Bacteriol 2010; 192:3024-32. [PMID: 20233920 PMCID: PMC2901689 DOI: 10.1128/jb.01649-09] [Citation(s) in RCA: 335] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2009] [Accepted: 03/05/2010] [Indexed: 11/20/2022] Open
Abstract
Streptococcus mutans is a key contributor to the formation of the extracellular polysaccharide (EPS) matrix in dental biofilms. The exopolysaccharides, which are mostly glucans synthesized by streptococcal glucosyltransferases (Gtfs), provide binding sites that promote accumulation of microorganisms on the tooth surface and further establishment of pathogenic biofilms. This study explored (i) the role of S. mutans Gtfs in the development of the EPS matrix and microcolonies in biofilms, (ii) the influence of exopolysaccharides on formation of microcolonies, and (iii) establishment of S. mutans in a multispecies biofilm in vitro using a novel fluorescence labeling technique. Our data show that the ability of S. mutans strains defective in the gtfB gene or the gtfB and gtfC genes to form microcolonies on saliva-coated hydroxyapatite surfaces was markedly disrupted. However, deletion of both gtfB (associated with insoluble glucan synthesis) and gtfC (associated with insoluble and soluble glucan synthesis) is required for the maximum reduction in EPS matrix and biofilm formation. S. mutans grown with sucrose in the presence of Streptococcus oralis and Actinomyces naeslundii steadily formed exopolysaccharides, which allowed the initial clustering of bacterial cells and further development into highly structured microcolonies. Concomitantly, S. mutans became the major species in the mature biofilm. Neither the EPS matrix nor microcolonies were formed in the presence of glucose in the multispecies biofilm. Our data show that GtfB and GtfC are essential for establishment of the EPS matrix, but GtfB appears to be responsible for formation of microcolonies by S. mutans; these Gtf-mediated processes may enhance the competitiveness of S. mutans in the multispecies environment in biofilms on tooth surfaces.
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Affiliation(s)
- H. Koo
- Center for Oral Biology, University of Rochester Medical Center, Rochester, New York, Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York, Department of Preventive Dentistry, School of Dentistry and Institute of Oral Bioscience, Chonbuk National University, Jeonju, Republic of Korea
| | - J. Xiao
- Center for Oral Biology, University of Rochester Medical Center, Rochester, New York, Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York, Department of Preventive Dentistry, School of Dentistry and Institute of Oral Bioscience, Chonbuk National University, Jeonju, Republic of Korea
| | - M. I. Klein
- Center for Oral Biology, University of Rochester Medical Center, Rochester, New York, Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York, Department of Preventive Dentistry, School of Dentistry and Institute of Oral Bioscience, Chonbuk National University, Jeonju, Republic of Korea
| | - J. G. Jeon
- Center for Oral Biology, University of Rochester Medical Center, Rochester, New York, Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York, Department of Preventive Dentistry, School of Dentistry and Institute of Oral Bioscience, Chonbuk National University, Jeonju, Republic of Korea
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77
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Role of extracellular DNA in initial bacterial adhesion and surface aggregation. Appl Environ Microbiol 2010; 76:3405-8. [PMID: 20363802 DOI: 10.1128/aem.03119-09] [Citation(s) in RCA: 206] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Extracellular DNA (eDNA) is an important component of the biofilm matrix. We show that removal of eDNA from Gram-positive bacteria reduces initial adhesion to and aggregation of bacteria on surfaces. Thermodynamic analyses indicated that eDNA introduces favorable acid-base interactions, explaining the effect of eDNA on aggregation and adhesion to the surface.
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78
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Mungkalasiri J, Bedel L, Emieux F, Doré J, Renaud FNR, Sarantopoulos C, Maury F. CVD Elaboration of Nanostructured TiO2-Ag Thin Films with Efficient Antibacterial Properties. ACTA ACUST UNITED AC 2010. [DOI: 10.1002/cvde.200906764] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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79
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Bacteria can form interconnected microcolonies when a self-excreted product reduces their surface motility: evidence from individual-based model simulations. Theory Biosci 2009; 129:1-13. [DOI: 10.1007/s12064-009-0078-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2009] [Accepted: 11/10/2009] [Indexed: 12/22/2022]
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Xiao J, Koo H. Structural organization and dynamics of exopolysaccharide matrix and microcolonies formation by Streptococcus mutans in biofilms. J Appl Microbiol 2009; 108:2103-13. [PMID: 19941630 DOI: 10.1111/j.1365-2672.2009.04616.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIMS To investigate the structural organization and dynamics of exopolysaccharides (EPS) matrix and microcolonies formation by Streptococcus mutans during the biofilm development process. METHODS AND RESULTS Biofilms of Strep. mutans were formed on saliva-coated hydroxyapatite (sHA) discs in the presence of glucose or sucrose (alone or mixed with starch). At specific time points, biofilms were subjected to confocal fluorescence imaging and computational analysis. EPS matrix was steadily formed on sHA surface in the presence of sucrose during the first 8 h followed by a threefold biomass increase between 8 and 30 h of biofilm development. The initial formation and further development of three-dimensional microcolony structure occurred concomitantly with EPS matrix synthesis. Tridimensional renderings showed EPS closely associated with microcolonies throughout the biofilm development process forming four distinct domains (i) between sHA surface and microcolonies, (ii) within, (iii) covering and (iv) filling the spaces between microcolonies. The combination of starch and sucrose resulted in rapid formation of elevated amounts of EPS matrix and faster assembly of microcolonies by Strep. mutans, which altered their structural organization and susceptibility of the biofilm to acid killing (vs sucrose-grown biofilms; P < 0.05). CONCLUSIONS Our data indicate that EPS modulate the development, sequence of assembly and spatial distribution of microcolonies by Strep. mutans. SIGNIFICANCE AND IMPACT OF THE STUDY Simultaneous visualization and analysis of EPS matrix and microcolonies provide a more precise examination of the structural organization of biofilms than labelling bacteria alone, which could be a useful approach to elucidate the exact mechanisms by which Strep. mutans influences oral biofilm formation and possibly identify novel targets for effective antibiofilm therapies.
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Affiliation(s)
- J Xiao
- Eastman Department of Dentistry, University of Rochester, Rochester, NY 14642, USA
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81
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Role of the Streptococcus mutans irvA gene in GbpC-independent, dextran-dependent aggregation and biofilm formation. Appl Environ Microbiol 2009; 75:7037-43. [PMID: 19783751 DOI: 10.1128/aem.01015-09] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Dextran-dependent aggregation (DDAG) of Streptococcus mutans is an in vitro phenomenon that is believed to represent a property of the organism that is beneficial for sucrose-dependent biofilm development. GbpC, a cell surface glucan-binding protein, is responsible for DDAG in S. mutans when cultured under defined stressful conditions. Recent reports have described a putative transcriptional regulator gene, irvA, located just upstream of gbpC, that is normally repressed by the product of an adjacent gene, irvR. When repression of irvA is relieved, there is a resulting increase in the expression of GbpC and decreases in competence and synthesis of the antibiotic mutacin I. This study examined the role of irvA in DDAG and biofilm formation by engineering strains that overexpressed irvA (IrvA+) on an extrachromosomal plasmid. The IrvA+ strain displayed large aggregation particles that did not require stressful growth conditions. A novel finding was that overexpression of irvA in a gbpC mutant background retained a measure of DDAG, albeit very small aggregation particles. Biofilms formed by the IrvA+ strain in the parental background possessed larger-than-normal microcolonies. In a gbpC mutant background, the overexpression of irvA reversed the fragile biofilm phenotype normally associated with loss of GbpC. Real-time PCR and Northern blot analyses found that expression of gbpC did not change significantly in the IrvA+ strain but expression of spaP, encoding the major surface adhesin P1, increased significantly. Inactivation of spaP eliminated the small-particle DDAG. The results suggest that IrvA promotes DDAG not only by GbpC, but also via an increase in P1.
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82
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Individual-based models for stage structured populations: formulation of “no regression” development equations. J Math Biol 2009; 60:831-48. [DOI: 10.1007/s00285-009-0287-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2009] [Revised: 07/23/2009] [Indexed: 10/20/2022]
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83
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Huq A, Whitehouse CA, Grim CJ, Alam M, Colwell RR. Biofilms in water, its role and impact in human disease transmission. Curr Opin Biotechnol 2008; 19:244-7. [PMID: 18524568 DOI: 10.1016/j.copbio.2008.04.005] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2008] [Revised: 04/07/2008] [Accepted: 04/21/2008] [Indexed: 11/28/2022]
Abstract
Understanding the mechanism of biofilm formation is the first step in determining its function and, thereby, its impact and role in the environment. Extensive studies accomplished during the past few years have elucidated the genetics and biochemistry of biofilm formation. Cell-to-cell communication, that is, quorum sensing, is a key factor in the initiation of biofilm. Occurrence of viable but nonculturable bacteria, including Vibrio cholerae in biofilms has been reported and most likely such cells were overlooked previously because appropriate methods of detection were not employed. For this reason discovery and investigation of this important bacterial ecological niche in the environment were impeded.
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Affiliation(s)
- Anwar Huq
- University of Maryland, Maryland Pathogen Research Institute, 3132 Bioscience Research, Building #413, College Park, MD 20742, United States.
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