Chapter 1 : Factors That Impact Biofilm Structure and Function

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This chapter focuses on the relationships among biofilm development, the environment, and antimicrobial tolerance for the paradigm organism . While a specific strain of consistently produces the same biofilm structure under one laboratory culturing condition, the same strain produces a very different biofilm structure under different culturing conditions. Investigators have discovered that biofilms grown in vitro reproducibly form specific structures that are affected by a plethora of conditions. For , two general biofilm shapes have been observed using the flow cell system: structured biofilms and flat biofilms. While the environmental sensing mechanisms and the regulatory pathways leading to the formation of specific biofilm structures have not been fully elucidated, it is clear that many factors are important for this process. A focus of recent work has been on identifying the signal transduction and regulatory pathways that control biofilm formation and that integrate different environmental signals during biofilm development. The chapter provides an outline about the regulation of biofilm formation by cyclic-di-GMP (c-di-GMP) and two-component systems (TCSs). Researchers are currently trying to determine the nature of these environmental signals, and as they do, our understanding of which environments promote or impair biofilm formation will grow. Microbial fuel cells and wastewater treatment communities are a few examples of engineered, structured communities that could benefit from such an approach.

Citation: Tseng B, Parsek M. 2013. Factors That Impact Biofilm Structure and Function, p 3-20. In Vasil M, Darwin A (ed), Regulation of Bacterial Virulence. ASM Press, Washington, DC. doi: 10.1128/9781555818524.ch1
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Figure 1

Models of flat versus structured biofilm formation in . Initial steps of biofilm formation are suggested to be the same for flat and structured biofilms. After initial steps, however, maturation of the different structures is suggested to follow different developmental pathways. There are two forms of structured biofilms (structured biofilms I and II). Aggregates of cells clonally expand to produce the structured biofilm I phenotype, while motile cells move to top nonmotile aggregates of cells to form mushroom-shaped structures in the structured biofilm II phenotype. Flat biofilms are formed through the clonal expansion of motile cells. Blue cylinders represent motile cells, and orange cylinders represent nonmotile cells. Adapted from Kirisits and Parsek, 2006, with permission from John Wiley and Sons. doi:10.1128/9781555818524.ch1f1

Citation: Tseng B, Parsek M. 2013. Factors That Impact Biofilm Structure and Function, p 3-20. In Vasil M, Darwin A (ed), Regulation of Bacterial Virulence. ASM Press, Washington, DC. doi: 10.1128/9781555818524.ch1
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Image of Figure 2
Figure 2

Type IV pilus mutants form biofilms that are morphologically distinct from those of the wild-type strain. (A) Fourday- old biofilms of wild-type and Δ strains of grown in glucose-based minimal medium. A 1:1 mixture of CFP- and YFP-expressing cells of the same strain was used to initiate the biofilm. (B) Ninety-eight-hour-old biofilms of GFPexpressing wild-type and Δ strains of grown in citrate-based minimal medium. Crosshairs (A) and white triangles (B) indicate the positions of vertical cross sections shown on the right and bottom of each image. Scale bar, 20 μm. Modified from Klausen et al., 2003a (A), and Heydorn et al., 2000 (B), with permission from John Wiley and Sons and the Society for General Microbiology, respectively. doi:10.1128/9781555818524.ch1f2

Citation: Tseng B, Parsek M. 2013. Factors That Impact Biofilm Structure and Function, p 3-20. In Vasil M, Darwin A (ed), Regulation of Bacterial Virulence. ASM Press, Washington, DC. doi: 10.1128/9781555818524.ch1
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Figure 3

The carbon source affects biofilm morphology. Shown are 48-hour-old biofilms of GFP-expressing wild-type and ΔΔ strains of grown in media with different carbon sources. SV, side view (x, z-plane); TD, top down view (x, y-plane). Reproduced from Shrout et al., 2006, with permission from John Wiley and Sons. doi:10.1128/9781555818524.ch1f3

Citation: Tseng B, Parsek M. 2013. Factors That Impact Biofilm Structure and Function, p 3-20. In Vasil M, Darwin A (ed), Regulation of Bacterial Virulence. ASM Press, Washington, DC. doi: 10.1128/9781555818524.ch1
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Figure 4

Overproduction of exopolysaccharides creates more structured biofilms. (A) Five-day-old biofilms of the GFPexpressing wild type (PAO1) and an isogenic, alginate-overproducing (PDO300) strain of grown in defined rich medium. White triangles indicate the position of vertical cross sections shown on the right and bottom of each image. Bar, 20 μm. (B) Three-day-old biofilms of GFP-expressing wild type (WT) and RSCV MJK8 of grown in defined rich medium. Modified from Hentzer et al., 2001 (A), and Kirisits et al., 2005 (B), with permission from the American Society for Microbiology. doi:10.1128/9781555818524.ch1f4

Citation: Tseng B, Parsek M. 2013. Factors That Impact Biofilm Structure and Function, p 3-20. In Vasil M, Darwin A (ed), Regulation of Bacterial Virulence. ASM Press, Washington, DC. doi: 10.1128/9781555818524.ch1
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1. Absalon, C.,, K. Van Dellen,, and P. I. Watnick. 2011. A communal bacterial adhesin anchors biofilm and bystander cells to surfaces. PLoS Pathog. 7:e1002210.
2. Allesen-Holm, M.,, K. B. Barken,, L. Yang,, M. Klausen,, J. S. Webb,, S. Kjelleberg,, S. Molin,, M. Givskov,, and T. Tolker-Nielsen. 2006. A characterization of DNA release in Pseudomonas aeruginosa cultures and biofilms. Mol. Microbiol. 59:11141128.
3. Alvarez-Ortega, C.,, and C. S. Harwood. 2007. Responses of Pseudomonas aeruginosa to low oxygen indicate that growth in the cystic fibrosis lung is by aerobic respiration. Mol. Microbiol. 65:153165.
4. An, S.,, J. Wu,, and L. H. Zhang. 2010. Modulation of Pseudomonas aeruginosa biofilm dispersal by a cyclic-di-GMP phosphodiesterase with a putative hypoxia-sensing domain. Appl. Environ. Microbiol. 76:81608173.
5. Banin, E.,, M. L. Vasil,, and E. P. Greenberg. 2005. Iron and Pseudomonas aeruginosa biofilm formation. Proc. Natl. Acad. Sci. USA 102:1107611081.
6. Barken, K. B.,, S. J. Pamp,, L. Yang,, M. Gjermansen,, J. J. Bertrand,, M. Klausen,, M. Givskov,, C. B. Whitchurch,, J. N. Engel,, and T. Tolker-Nielsen. 2008. Roles of type IV pili, flagellum-mediated motility and extracellular DNA in the formation of mature multicellular structures in Pseudomonas aeruginosa biofilms. Environ. Microbiol. 10:23312343.
7. Barton, H. A.,, Z. Johnson,, C. D. Cox,, A. I. Vasil,, and M. L. Vasil. 1996. Ferric uptake regulator mutants of Pseudomonas aeruginosa with distinct alterations in the iron-dependent repression of exotoxin A and siderophores in aerobic and microaerobic environments. Mol. Microbiol. 21:10011017.
8. Berg, H. C. 2003. The rotary motor of bacterial flagella. Annu. Rev. Biochem. 72:1954.
9. Bjarnsholt, T.,, P. O. Jensen,, M. Burmolle,, M. Hentzer,, J. A. Haagensen,, H. P. Hougen,, H. Calum,, K. G. Madsen,, C. Moser,, S. Molin,, N. Hoiby,, and M. Givskov. 2005. Pseudomonas aeruginosa tolerance to tobramycin, hydrogen peroxide and polymorphonuclear leukocytes is quorum-sensing dependent. Microbiology 151:373383.
10. Blair, K. M.,, L. Turner,, J. T. Winkelman,, H. C. Berg,, and D. B. Kearns. 2008. A molecular clutch disables flagella in the Bacillus subtilis biofilm. Science 320:16361638.
11. Boles, B. R.,, M. Thoendel,, and P. K. Singh. 2005. Rhamnolipids mediate detachment of Pseudomonas aeruginosa from biofilms. Mol. Microbiol. 57:12101223.
12. Borlee, B. R.,, A. D. Goldman,, K. Murakami,, R. Samudrala,, D. J. Wozniak,, and M. R. Parsek. 2010. Pseudomonas aeruginosa uses a cyclic-di-GMP-regulated adhesin to reinforce the biofilm extracellular matrix. Mol. Microbiol. 75:827842.
13. Borriello, G.,, E. Werner,, F. Roe,, A. M. Kim,, G. D. Ehrlich,, and P. S. Stewart. 2004. Oxygen limitation contributes to antibiotic tolerance of Pseudomonas aeruginosa in biofilms. Antimicrob. Agents Chemother. 48:26592664.
14. Brencic, A.,, and S. Lory. 2009. Determination of the regulon and identification of novel mRNA targets of Pseudomonas aeruginosa RsmA. Mol. Microbiol. 72:612632.
15. Brencic, A.,, K. A. McFarland,, H. R. McManus,, S. Castang,, I. Mogno,, S. L. Dove,, and S. Lory. 2009. The GacS/GacA signal transduction system of Pseudomonas aeruginosa acts exclusively through its control over the transcription of the RsmY and RsmZ regulatory small RNAs. Mol. Microbiol. 73:434445.
16. Byrd, M. S.,, I. Sadovskaya,, E. Vinogradov,, H. Lu,, A. B. Sprinkle,, S. H. Richardson,, L. Ma,, B. Ralston,, M. R. Parsek,, E. M. Anderson,, J. S. Lam,, and D. J. Wozniak. 2009. Genetic and biochemical analyses of the Pseudomonas aeruginosa Psl exopolysaccharide reveal overlapping roles for polysaccharide synthesis enzymes in Psl and LPS production. Mol. Microbiol. 73:622638.
17. Colvin, K. M.,, V. D. Gordon,, K. Murakami,, B. R. Borlee,, D. J. Wozniak,, G. C. Wong,, and M. R. Parsek. 2011. The Pel polysaccharide can serve a structural and protective role in the biofilm matrix of Pseudomonas aeruginosa. PLoS Pathog. 7:e1001264.
18. Cornelis, P. 2010. Iron uptake and metabolism in pseudomonads. Appl. Microbiol. Biotechnol. 86:16371645.
19. Costerton, J. W.,, Z. Lewandowski,, D. E. Caldwell,, D. R. Korber,, and H. M. Lappin-Scott. 1995. Microbial biofilms. Annu. Rev. Microbiol. 49:711745.
20. Cox, C. D.,, and P. Adams. 1985. Siderophore activity of pyoverdin for Pseudomonas aeruginosa. Infect. Immun. 48:130138.
21. Cox, C. D.,, and R. Graham. 1979. Isolation of an iron-binding compound from Pseudomonas aeruginosa. J. Bacteriol. 137:357364.
22. Danese, P. N.,, L. A. Pratt,, and R. Kolter. 2000. Exopolysaccharide production is required for development of Escherichia coli K-12 biofilm architecture. J. Bacteriol. 182:35933596.
23. D’Argenio, D. A.,, M. W. Calfee,, P. B. Rainey,, and E. C. Pesci. 2002. Autolysis and autoaggregation in Pseudomonas aeruginosa colony morphology mutants. J. Bacteriol. 184:64816489.
24. Davey, M. E.,, N. C. Caiazza,, and G. A. O’Toole. 2003. Rhamnolipid surfactant production affects biofilm architecture in Pseudomonas aeruginosa PAO1. J. Bacteriol. 185:10271036.
25. Davies, D. G.,, M. R. Parsek,, J. P. Pearson,, B. H. Iglewski,, J. W. Costerton,, and E. P. Greenberg. 1998. The involvement of cell-to-cell signals in the development of a bacterial biofilm. Science 280:295298.
26. De Kievit, T. R.,, R. Gillis,, S. Marx,, C. Brown,, and B. H. Iglewski. 2001. Quorum-sensing genes in Pseudomonas aeruginosa biofilms: their role and expression patterns. Appl. Environ. Microbiol. 67:18651873.
27. Dow, J. M.,, Y. Fouhy,, J. Lucey,, and R. P. Ryan,. 2007. Cyclic di-GMP as an intracellular signal regulating bacterial biofilm formation, p. 7193. In S. Kjelleberg, and M. Givskov (ed.), The Biofilm Mode of Life: Mechanisms and Adaptations. Horizon Bioscience, Norfolk, United Kingdom.
28. Fong, J. C.,, K. Karplus,, G. K. Schoolnik,, and F. H. Yildiz. 2006. Identification and characterization of RbmA, a novel protein required for the development of rugose colony morphology and biofilm structure in Vibrio cholerae. J. Bacteriol. 188:10491059.
29. Fong, J. C.,, and F. H. Yildiz. 2007. The rbmBCDEF gene cluster modulates development of rugose colony morphology and biofilm formation in Vibrio cholerae. J. Bacteriol. 189:23192330.
30. Friedman, L.,, and R. Kolter. 2004a. Genes involved in matrix formation in Pseudomonas aeruginosa PA14 biofilms. Mol. Microbiol. 51:675690.
31. Friedman, L.,, and R. Kolter. 2004b. Two genetic loci produce distinct carbohydrate-rich structural components of the Pseudomonas aeruginosa biofilm matrix. J. Bacteriol. 186:44574465.
32. Galperin, M. Y. 2005. A census of membrane-bound and intracellular signal transduction proteins in bacteria: bacterial IQ, extroverts and introverts. BMC Microbiol. 5:35.
33. Gibiansky, M. L.,, J. C. Conrad,, F. Jin,, V. D. Gordon,, D. A. Motto,, M. A. Mathewson,, W. G. Stopka,, D. C. Zelasko,, J. D. Shrout,, and G. C. Wong. 2010. Bacteria use type IV pili to walk upright and detach from surfaces. Science 330:197.
34. Glick, R.,, C. Gilmour,, J. Tremblay,, S. Satanower,, O. Avidan,, E. Deziel,, E. P. Greenberg,, K. Poole,, and E. Banin. 2010. Increase in rhamnolipid synthesis under iron-limiting conditions influences surface motility and biofilm formation in Pseudomonas aeruginosa. J. Bacteriol. 192:29732980.
35. Gotz, F. 2002. Staphylococcus and biofilms. Mol. Microbiol. 43:13671378.
36. Haagensen, J. A.,, M. Klausen,, R. K. Ernst,, S. I. Miller,, A. Folkesson,, T. Tolker-Nielsen,, and S. Molin. 2007. Differentiation and distribution of colistin- and sodium dodecyl sulfate-tolerant cells in Pseudomonas aeruginosa biofilms. J. Bacteriol. 189:2837.
37. Hengge, R. 2009. Principles of c-di-GMP signalling in bacteria. Nat. Rev. Microbiol. 7:263273.
38. Hentzer, M.,, G. M. Teitzel,, G. J. Balzer,, A. Heydorn,, S. Molin,, M. Givskov,, and M. R. Parsek. 2001. Alginate overproduction affects Pseudomonas aeruginosa biofilm structure and function. J.Bacteriol. 183:53955401.
39. Heydorn, A.,, B. Ersboll,, J. Kato,, M. Hentzer,, M. R. Parsek,, T. Tolker-Nielsen,, M. Givskov,, and S. Molin. 2002. Statistical analysis of Pseudomonas aeruginosa biofilm development: impact of mutations in genes involved in twitching motility, cell-to-cell signaling, and stationary-phase sigma factor expression. Appl. Environ. Microbiol. 68:20082017.
40. Heydorn, A.,, A. T. Nielsen,, M. Hentzer,, C. Sternberg,, M. Givskov,, B. K. Ersboll,, and S. Molin. 2000. Quantification of biofilm structures by the novel computer program COMSTAT. Microbiology 146(Pt. 10):23952407.
41. Hickman, J. W.,, D. F. Tifrea,, and C. S. Harwood. 2005. A chemosensory system that regulates biofilm formation through modulation of cyclic diguanylate levels. Proc. Natl. Acad. Sci. USA 102:1442214427.
42. Hoffman, L. R.,, D. A. D’Argenio,, M. J. MacCoss,, Z. Zhang,, R. A. Jones,, and S. I. Miller. 2005. Aminoglycoside antibiotics induce bacterial biofilm formation. Nature 436:11711175.
43. Irie, Y.,, M. Starkey,, A. N. Edwards,, D. J. Wozniak,, T. Romeo,, and M. R. Parsek. 2010. Pseudomonas aeruginosa biofilm matrix polysaccharide Psl is regulated transcriptionally by RpoS and post-transcriptionally by RsmA. Mol. Microbiol. 78:158172.
44. Jackson, K. D.,, M. Starkey,, S. Kremer,, M. R. Parsek,, and D. J. Wozniak. 2004. Identification of psl, a locus encoding a potential exopolysaccharide that is essential for Pseudomonas aeruginosa PAO1 biofilm formation. J. Bacteriol. 186:44664475.
45. Jin, F.,, J. C. Conrad,, M. L. Gibiansky,, and G. C. Wong. 2011. Bacteria use type-IV pili to slingshot on surfaces. Proc. Natl. Acad. Sci. USA 108:1261712622.
46. Kaneko, Y.,, M. Thoendel,, O. Olakanmi,, B. E. Britigan,, and P. K. Singh. 2007. The transition metal gallium disrupts Pseudomonas aeruginosa iron metabolism and has antimicrobial and antibiofilm activity. J. Clin. Investig. 117:877888.
47. Karatan, E.,, and P. Watnick. 2009. Signals, regulatory networks, and materials that build and break bacterial biofilms. Microbiol. Mol. Biol. Rev. 73:310347.
48. Kazmierczak, B. I.,, M. B. Lebron,, and T. S. Murray. 2006. Analysis of FimX, a phosphodiesterase that governs twitching motility in Pseudomonas aeruginosa. Mol. Microbiol. 60:10261043.
49. Kearns, D. B.,, J. Robinson,, and L. J. Shimkets. 2001. Pseudomonas aeruginosa exhibits directed twitching motility up phosphatidylethanolamine gradients. J. Bacteriol. 183:763767.
50. Kirisits, M. J.,, and M. R. Parsek. 2006. Does Pseudomonas aeruginosa use intercellular signalling to build biofilm communities? Cell. Microbiol. 8:18411849.
51. Kirisits, M. J.,, L. Prost,, M. Starkey,, and M. R. Parsek. 2005. Characterization of colony morphology variants isolated from Pseudomonas aeruginosa biofilms. Appl. Environ. Microbiol. 71:48094821.
52. Klausen, M.,, A. Aaes-Jorgensen,, S. Molin,, and T. Tolker-Nielsen. 2003a. Involvement of bacterial migration in the development of complex multicellular structures in Pseudomonas aeruginosa biofilms. Mol. Microbiol. 50:6168.
53. Klausen, M.,, A. Heydorn,, P. Ragas,, L. Lambertsen,, A. Aaes-Jorgensen,, S. Molin,, and T. Tolker-Nielsen. 2003b. Biofilm formation by Pseudomonas aeruginosa wild type, flagella and type IV pili mutants. Mol. Microbiol. 48:15111524.
54. Kohler, T.,, L. K. Curty,, F. Barja,, C. van Delden,, and J. C. Pechere. 2000. Swarming of Pseudomonas aeruginosa is dependent on cell-to-cell signaling and requires flagella and pili. J. Bacteriol. 182:59905996.
55. Kuchma, S. L.,, K. M. Brothers,, J. H. Merritt,, N. T. Liberati,, F. M. Ausubel,, and G. A. O’Toole. 2007. BifA, a cyclic-Di-GMP phosphodiesterase, inversely regulates biofilm formation and swarming motility by Pseudomonas aeruginosa PA14. J. Bacteriol. 189:81658178.
56. Kuchma, S. L.,, J. P. Connolly,, and G. A. O’Toole. 2005. A three-component regulatory system regulates biofilm maturation and type III secretion in Pseudomonas aeruginosa. J. Bacteriol. 187:14411454.
57. Kulasakara, H.,, V. Lee,, A. Brencic,, N. Liberati,, J. Urbach,, S. Miyata,, D. G. Lee,, A. N. Neely,, M. Hyodo,, Y. Hayakawa,, F. M. Ausubel,, and S. Lory. 2006. Analysis of Pseudomonas aeruginosa diguanylate cyclases and phosphodiesterases reveals a role for bis-(3'-5')-cyclic-GMP in virulence. Proc. Natl. Acad. Sci. USA 103:28392844.
58. Kulasekara, H. D.,, I. Ventre,, B. R. Kulasekara,, A. Lazdunski,, A. Filloux,, and S. Lory. 2005. A novel two-component system controls the expression of Pseudomonas aeruginosa fimbrial cup genes. Mol. Microbiol. 55:368380.
59. Landry, R. M.,, D. An,, J. T. Hupp,, P. K. Singh,, and M. R. Parsek. 2006. Mucin-Pseudomonas aeruginosa interactions promote biofilm formation and antibiotic resistance. Mol. Microbiol. 59:142151.
60. Latasa, C.,, C. Solano,, J. R. Penades,, and I. Lasa. 2006. Biofilm-associated proteins. C. R. Biol. 329:849857.
61. Lawrence, J. R.,, D. R. Korber,, B. D. Hoyle,, J. W. Costerton,, and D. E. Caldwell. 1991. Optical sectioning of microbial biofilms. J.Bacteriol. 173:65586567.
62. Lee, V. T.,, J. M. Matewish,, J. L. Kessler,, M. Hyodo,, Y. Hayakawa,, and S. Lory. 2007. A cyclic-di-GMP receptor required for bacterial exopolysaccharide production. Mol. Microbiol. 65:14741484.
63. Lequette, Y.,, and E. P. Greenberg. 2005. Timing and localization of rhamnolipid synthesis gene expression in Pseudomonas aeruginosa biofilms. J. Bacteriol. 187:3744.
64. Li, Y.,, H. Xia,, F. Bai,, H. Xu,, L. Yang,, H. Yao,, L. Zhang,, X. Zhang,, Y. Bai,, P. E. Saris,, T. Tolker-Nielsen,, and M. Qiao. 2007. Identification of a new gene PA5017 involved in flagella-mediatedmotility, chemotaxis and biofilm formation in Pseudomonas aeruginosa. FEMS Microbiol. Lett. 272:188195.
65. Ma, L.,, M. Conover,, H. Lu,, M. R. Parsek,, K. Bayles,, and D. J. Wozniak. 2009. Assembly and development of the Pseudomonas aeruginosa biofilm matrix. PLoS Pathog. 5:e1000354.
66. Ma, L.,, K. D. Jackson,, R. M. Landry,, M. R. Parsek,, and D. J. Wozniak. 2006. Analysis of Pseudomonas aeruginosa conditional Psl variants reveals roles for the Psl polysaccharide in adhesion and maintaining biofilm structure postattachment. J.Bacteriol. 188:82138221.
67. Martin, D. W.,, M. J. Schurr,, M. H. Mudd,, J. R. Govan,, B. W. Holloway,, and V. Deretic. 1993. Mechanism of conversion to mucoidy in Pseudomonas aeruginosa infecting cystic fibrosis patients. Proc. Natl. Acad. Sci. USA 90:83778381.
68. Marvasi, M.,, P. T. Visscher,, and L. Casillas Martinez. 2010. Exopolymeric substances (EPS) from Bacillus subtilis: polymers and genes encoding their synthesis. FEMS Microbiol. Lett. 313:19.
69. Masse, E.,, H. Salvail,, G. Desnoyers,, and M. Arguin. 2007. Small RNAs controlling iron metabolism. Curr. Opin. Microbiol. 10:140145.
70. Massol-Deya, A. A.,, J. Whallon,, R. F. Hickey,, and J. M. Tiedje. 1995. Channel structures in aerobic biofilms of fixed-film reactors treating contaminated groundwater. Appl. Environ. Microbiol. 61:769777.
71. Matsukawa, M.,, and E. P. Greenberg. 2004. Putative exopolysaccharide synthesis genes influence Pseudomonas aeruginosa biofilm development. J. Bacteriol. 186:44494456.
72. Mattick, J. S. 2002. Type IV pili and twitching motility. Annu. Rev. Microbiol. 56:289314.
73. May, T. B.,, D. Shinabarger,, R. Maharaj,, J. Kato,, L. Chu,, J. D. DeVault,, S. Roychoudhury,, N. A. Zielinski,, A. Berry,, R. K. Rothmel, et al. 1991. Alginate synthesis by Pseudomonas aeruginosa: a key pathogenic factor in chronic pulmonary infections of cystic fibrosis patients. Clin. Microbiol. Rev. 4:191206.
74. Meissner, A.,, V. Wild,, R. Simm,, M. Rohde,, C. Erck,, F. Bredenbruch,, M. Morr,, U. Romling,, and S. Haussler. 2007. Pseudomonas aeruginosa cupA-encoded fimbriae expression is regulated by a GGDEF and EAL domain-dependent modulation of the intracellular level of cyclic diguanylate. Environ. Microbiol. 9:24752485.
75. Merritt, J. H.,, K. M. Brothers,, S. L. Kuchma,, and G. A. O’Toole. 2007. SadC reciprocally influences biofilm formation and swarming motility via modulation of exopolysaccharide production and flagellar function. J. Bacteriol. 189:81548164.
76. Merritt, J. H.,, D. G. Ha,, K. N. Cowles,, W. Lu,, D. K. Morales,, J. Rabinowitz,, Z. Gitai,, and G. A. O’Toole. 2010. Specific control of Pseudomonas aeruginosa surface-associated behaviors by two c-di-GMP diguanylate cyclases. mBio 1:e00183-10.
77. Mikkelsen, H.,, Z. Duck,, K. S. Lilley,, and M. Welch. 2007. Interrelationships between colonies, biofilms, and planktonic cells of Pseudomonas aeruginosa. J. Bacteriol. 189:24112416.
78. Mikkelsen, H.,, M. Sivaneson,, and A. Filloux. 2011. Key two-component regulatory systems that control biofilm formation in Pseudomonas aeruginosa. Environ. Microbiol. 13:16661681.
79. Mulcahy, H.,, L. Charron-Mazenod,, and S. Lewenza. 2010. Pseudomonas aeruginosa produces an extracellular deoxyribonuclease that is required for utilization of DNA as a nutrient source. Environ. Microbiol. 12:16211629.
80. Musk, D. J.,, D. A. Banko,, and P. J. Hergenrother. 2005. Iron salts perturb biofilm formation and disrupt existing biofilms of Pseudomonas aeruginosa. Chem. Biol. 12:789796.
81. Nivens, D. E.,, D. E. Ohman,, J. Williams,, and M. J. Franklin. 2001. Role of alginate and its O acetylation in formation of Pseudomonas aeruginosa microcolonies and biofilms. J.Bacteriol. 183:10471057.
82. Ochsner, U. A.,, Z. Johnson,, and M. L. Vasil. 2000. Genetics and regulation of two distinct haem-uptake systems, phu and has, in Pseudomonas aeruginosa. Microbiology 146(Pt. 1):185198.
83. Ochsner, U. A.,, A. I. Vasil,, and M. L. Vasil. 1995. Role of the ferric uptake regulator of Pseudomonas aeruginosa in the regulation of siderophores and exotoxin A expression: purification and activity on iron-regulated promoters. J. Bacteriol. 177:71947201.
84. Oglesby, A. G.,, J. M. Farrow III,, J. H. Lee,, A. P. Tomaras,, E. P. Greenberg,, E. C. Pesci,, and M. L. Vasil. 2008. The influence of iron on Pseudomonas aeruginosa physiology: a regulatory link between iron and quorum sensing. J. Biol. Chem. 283:15558–15567.
85. O’Toole, G.,, H. B. Kaplan,, and R. Kolter. 2000a. Biofilm formation as microbial development. Annu. Rev. Microbiol. 54:4979.
86. O’Toole, G. A.,, K. A. Gibbs,, P. W. Hager,, P. V. Phibbs, Jr.,, and R. Kolter. 2000b. The global carbon metabolism regulator Crc is a component of a signal transduction pathway required for biofilm development by Pseudomonas aeruginosa. J. Bacteriol. 182:425431.
87. O’Toole, G. A.,, and R. Kolter. 1998a. Flagellar and twitching motility are necessary for Pseudomonas aeruginosa biofilm development. Mol. Microbiol. 30:295304.
88. O’Toole, G. A.,, and R. Kolter. 1998b. Initiation of biofilm formation in Pseudomonas fluorescens WCS365 proceeds via multiple, convergent signalling pathways: a genetic analysis. Mol. Microbiol. 28:449461.
89. Overhage, J.,, M. Schemionek,, J. S. Webb,, and B. H. Rehm. 2005. Expression of the psl operon in Pseudomonas aeruginosa PAO1 biofilms: PslA performs an essential function in biofilm formation. Appl. Environ. Microbiol. 71:44074413.
90. Pamp, S. J.,, and T. Tolker-Nielsen. 2007. Multiple roles of biosurfactants in structural biofilm development by Pseudomonas aeruginosa. J. Bacteriol. 189:25312539.
91. Parkins, M. D.,, H. Ceri,, and D. G. Storey. 2001. Pseudomonas aeruginosa GacA, a factor in multihost virulence, is also essential for biofilm formation. Mol. Microbiol. 40:12151226.
92. Patriquin, G. M.,, E. Banin,, C. Gilmour,, R. Tuchman,, E. P. Greenberg,, and K. Poole. 2008. Influence of quorum sensing and iron on twitching motility and biofilm formation in Pseudomonas aeruginosa. J. Bacteriol. 190:662671.
93. Petrova, O. E.,, and K. Sauer. 2009. A novel signaling network essential for regulating Pseudomonas aeruginosa biofilm development. PLoS Pathog. 5:e1000668.
94. Petrova, O. E.,, and K. Sauer. 2010. The novel two-component regulatory system BfiSR regulates biofilm development by controlling the small RNA rsmZ through CafA. J. Bacteriol. 192:52755288.
95. Petrova, O. E.,, J. R. Schurr,, M. J. Schurr,, and K. Sauer. 2011. The novel Pseudomonas aeruginosa two-component regulator BfmR controls bacteriophage-mediated lysis and DNA release during biofilm development through PhdA. Mol. Microbiol. 81:767783.
96. Picioreanu, C.,, M. C. van Loosdrecht,, and J. J. Heijnen. 1998. Mathematical modeling of biofilm structure with a hybrid differential-discrete cellular automaton approach. Biotechnol. Bioeng. 58:101116.
97. Rodrigue, A.,, Y. Quentin,, A. Lazdunski,, V. Mejean,, and M. Foglino. 2000. Two-component systems in Pseudomonas aeruginosa: why so many? Trends Microbiol. 8:498504.
98. Romero, D.,, C. Aguilar,, R. Losick,, and R. Kolter. 2010. Amyloid fibers provide structural integrity to Bacillus subtilis biofilms. Proc. Natl. Acad. Sci. USA 107:22302234.
99. Ryan, R. P.,, J. Lucey,, K. O’Donovan,, Y. McCarthy,, L. Yang,, T. Tolker-Nielsen,, and J. M. Dow. 2009. HD-GYP domain proteins regulate biofilm formation and virulence in Pseudomonas aeruginosa. Environ. Microbiol. 11:11261136.
100. Ryder, C.,, M. Byrd,, and D. J. Wozniak. 2007. Role of polysaccharides in Pseudomonas aeruginosa biofilm development. Curr. Opin. Microbiol. 10:644648.
101. Sauer, K.,, A. K. Camper,, G. D. Ehrlich,, J. W. Costerton,, and D. G. Davies. 2002. Pseudomonas aeruginosa displays multiple phenotypes during development as a biofilm. J. Bacteriol. 184:11401154.
102. Schmidt, J.,, M. Musken,, T. Becker,, Z. Magnowska,, D. Bertinetti,, S. Moller,, B. Zimmermann,, F. W. Herberg,, L. Jansch,, and S. Haussler. 2011. The Pseudomonas aeruginosa chemotaxis methyltransferase CheR1 impacts on bacterial surface sampling. PLoS One 6:e18184.
103. Shrout, J. D.,, D. L. Chopp,, C. L. Just,, M. Hentzer,, M. Givskov,, and M. R. Parsek. 2006. The impact of quorum sensing and swarming motility on Pseudomonas aeruginosa biofilm formation is nutritionally conditional. Mol. Microbiol. 62:12641277.
104. Singh, P. K.,, M. R. Parsek,, E. P. Greenberg,, and M. J. Welsh. 2002. A component of innate immunity prevents bacterial biofilm development. Nature 417:552555.
105. Soberon-Chavez, G.,, F. Lepine,, and E. Deziel. 2005. Production of rhamnolipids by Pseudomonas aeruginosa. Appl. Microbiol. Biotechnol. 68:718725.
106. Southey-Pillig, C. J.,, D. G. Davies,, and K. Sauer. 2005. Characterization of temporal protein production in Pseudomonas aeruginosa biofilms. J. Bacteriol. 187:81148126.
107. Stapper, A. P.,, G. Narasimhan,, D. E. Ohman,, J. Barakat,, M. Hentzer,, S. Molin,, A. Kharazmi,, N. Hoiby,, and K. Mathee. 2004. Alginate production affects Pseudomonas aeruginosa biofilm development and architecture, but is not essential for biofilm formation. J. Med. Microbiol. 53:679690.
108. Starkey, M.,, J. H. Hickman,, L. Ma,, N. Zhang,, S. De Long,, A. Hinz,, S. Palacios,, C. Manoil,, M. J. Kirisits,, T. D. Starner,, D. J. Wozniak,, C. S. Harwood,, and M. R. Parsek. 2009. Pseudomonas aeruginosa rugose small-colony variants have adaptations that likely promote persistence in the cystic fibrosis lung. J. Bacteriol. 191:34923503.
109. Steinberger, R. E.,, and P. A. Holden. 2005. Extracellular DNA in single- and multiple-species unsaturated biofilms. Appl. Environ. Microbiol. 71:54045410.
110. Stoodley, P.,, D. Debeer,, and Z. Lewandowski. 1994. Liquid flow in biofilm systems. Appl. Environ. Microbiol. 60:27112716.
111. Stoodley, P.,, K. Sauer,, D. G. Davies,, and J. W. Costerton. 2002. Biofilms as complex differentiated communities. Annu. Rev. Microbiol. 56:187209.
112. Thompson, L. S.,, J. S. Webb,, S. A. Rice,, and S. Kjelleberg. 2003. The alternative sigma factor RpoN regulates the quorum sensing gene rhlI in Pseudomonas aeruginosa. FEMS Microbiol. Lett. 220:187195.
113. Vasil, M. L.,, and U. A. Ochsner. 1999. The response of Pseudomonas aeruginosa to iron: genetics, biochemistry and virulence. Mol. Microbiol. 34:399413.
114. Vasseur, P.,, I. Vallet-Gely,, C. Soscia,, S. Genin,, and A. Filloux. 2005. The pel genes of the Pseudomonas aeruginosa PAK strain are involved at early and late stages of biofilm formation. Microbiology 151:985997.
115. Vilain, S.,, P. Cosette,, M. Hubert,, C. Lange,, G. A. Junter,, and T. Jouenne. 2004. Comparative proteomic analysis of planktonic and immobilized Pseudomonas aeruginosa cells: a multivariate statistical approach. Anal. Biochem. 329:120130.
116. Wang, X.,, J. F. Preston III,, and T. Romeo. 2004. The pgaABCD locus of Escherichia coli promotes the synthesis of a polysaccharide adhesin required for biofilm formation. J. Bacteriol. 186:27242734.
117. Whitchurch, C. B.,, T. Tolker-Nielsen,, P. C. Ragas,, and J. S. Mattick. 2002. Extracellular DNA required for bacterial biofilm formation. Science 295:1487.
118. Wilderman, P. J.,, N. A. Sowa,, D. J. FitzGerald,, P. C. FitzGerald,, S. Gottesman,, U. A. Ochsner,, and M. L. Vasil. 2004. Identification of tandem duplicate regulatory small RNAs in Pseudomonas aeruginosa involved in iron homeostasis. Proc. Natl. Acad. Sci. USA 101:97929797.
119. Williams, P.,, and M. Camara. 2009. Quorum sensing and environmental adaptation in Pseudomonas aeruginosa: a tale of regulatory networks and multifunctional signal molecules. Curr. Opin. Microbiol. 12:182191.
120. Wimpenny, J. W. T.,, and R. Colasanti. 1997. A unifying hypothesis for the structure of microbial biofilms based on cellular automaton models. FEMS Microbiol. Ecol. 22:116.
121. Wolfaardt, G. M.,, J. R. Lawrence,, R. D. Robarts,, S. J. Caldwell,, and D. E. Caldwell. 1994. Multicellular organization in a degradative biofilm community. Appl. Environ. Microbiol. 60:434446.
122. Wolff, J. A.,, C. H. MacGregor,, R. C. Eisenberg,, and P. V. Phibbs, Jr. 1991. Isolation and characterization of catabolite repression control mutants of Pseudomonas aeruginosa PAO. J. Bacteriol. 173:47004706.
123. Xu, K. D.,, P. S. Stewart,, F. Xia,, C. T. Huang,, and G. A. McFeters. 1998. Spatial physiological heterogeneity in Pseudomonas aeruginosa biofilm is determined by oxygen availability. Appl. Environ. Microbiol. 64:40354039.
124. Yang, L.,, K. B. Barken,, M. E. Skindersoe,, A. B. Christensen,, M. Givskov,, and T. Tolker-Nielsen. 2007. Effects of iron on DNA release and biofilm development by Pseudomonas aeruginosa. Microbiology 153:13181328.
125. Yang, L.,, Y. Hu,, Y. Liu,, J. Zhang,, J. Ulstrup,, and S. Molin. 2011. Distinct roles of extracellular polymeric substances in Pseudomonas aeruginosa biofilm development. Environ. Microbiol. 13:17051717.
126. Yang, L.,, M. Nilsson,, M. Gjermansen,, M. Givskov,, and T. Tolker-Nielsen. 2009. Pyoverdine and PQS mediated subpopulation interactions involved in Pseudomonas aeruginosa biofilm formation. Mol. Microbiol. 74:13801392.
127. Yildiz, F. H.,, and K. L. Visick. 2009. Vibrio biofilms: so much the same yet so different. Trends Microbiol. 17:109118.

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