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Slobodianyk-Kolomoiets M, Khlebas S, Mazur I, Rudnieva K, Potochilova V, Iungin O, Kamyshnyi O, Kamyshna I, Potters G, Spiers AJ, Moshynets O. Extracellular host DNA contributes to pathogenic biofilm formation during periodontitis. Front Cell Infect Microbiol 2024; 14:1374817. [PMID: 38779563 PMCID: PMC11109387 DOI: 10.3389/fcimb.2024.1374817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Accepted: 04/09/2024] [Indexed: 05/25/2024] Open
Abstract
Introduction Periodontal diseases are known to be associated with polymicrobial biofilms and inflammasome activation. A deeper understanding of the subgingival cytological (micro) landscape, the role of extracellular DNA (eDNA) during periodontitis, and contribution of the host immune eDNA to inflammasome persistence, may improve our understanding of the mechanisms underlaying severe forms of periodontitis. Methods In this work, subgingival biolfilms developing on biologically neutral polyethylene terephthalate films placed in gingival cavities of patients with chronic periodontitis were investigated by confocal laser scanning microscopy (CLSM). This allowed examination of realistic cytological landscapes and visualization of extracellular polymeric substances (EPS) including amyloids, total proteins, carbohydrates and eDNA, as well as comparison with several single-strain in vitro model biofilms produced by oral pathogens such as Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus gordonii, S. sanguinis and S. mitis. Fluorescence in situ hybridization (FISH) analysis was also used to identify eDNA derived from eubacteria, streptococci and members of the Bacteroides-Porphyromonas-Prevotella (BPP) group associated with periodontitis. Results Analysis of subgingival biofilm EPS revealed low levels of amyloids and high levels of eDNA which appears to be the main matrix component. However, bacterial eDNA contributed less than a third of the total eDNA observed, suggesting that host-derived eDNA released in neutrophil extracellular traps may be of more importance in the development of biofilms causing periodontitis. Discussion eDNA derived from host immunocompetent cells activated at the onset of periodontitis may therefore be a major driver of bacterial persistence and pathogenesis.
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Affiliation(s)
| | - Svitlana Khlebas
- Department of Dentistry, Shupyk National Healthcare University of Ukraine, Kyiv, Ukraine
| | - Iryna Mazur
- Department of Dentistry, Shupyk National Healthcare University of Ukraine, Kyiv, Ukraine
| | - Kateryna Rudnieva
- Central Clinical Diagnostic Laboratory, Kyiv Regional Clinical Hospital, Kyiv, Ukraine
- Department of Microbiology, Virology and Immunology, Bogomolets National Medical Academy, Kyiv, Ukraine
| | | | - Olga Iungin
- Biofilm Study Group, Department of Cell Regulatory Mechanisms, Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine, Kyiv, Ukraine
- Department of Biotechnology, Leather and Fur, Faculty of Chemical and Biopharmaceutical Technologies, Kyiv National University of Technologies and Design, Kyiv, Ukraine
| | - Olexandr Kamyshnyi
- Microbiology, Virology and Immunology Department, I. Horbachevsky Ternopil National Medical University, Ternopil, Ukraine
| | - Iryna Kamyshna
- Microbiology, Virology and Immunology Department, I. Horbachevsky Ternopil National Medical University, Ternopil, Ukraine
| | - Geert Potters
- Antwerp Maritime Academy, Antwerp, Belgium
- Department of Bioscience Engineering, University of Antwerp, Antwerp, Belgium
| | - Andrew J. Spiers
- School of Applied Sciences, Abertay University, Dundee, United Kingdom
| | - Olena Moshynets
- Biofilm Study Group, Department of Cell Regulatory Mechanisms, Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine, Kyiv, Ukraine
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Burnett AJN, Rodriguez E, Constable S, Lowrance B, Fish M, Weadge JT. WssI from the Gram-Negative Bacterial Cellulose Synthase is an O-acetyltransferase that Acts on Cello-oligomers with Several Acetyl Donor Substrates. J Biol Chem 2023:104849. [PMID: 37224964 PMCID: PMC10302187 DOI: 10.1016/j.jbc.2023.104849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 05/03/2023] [Accepted: 05/04/2023] [Indexed: 05/26/2023] Open
Abstract
In microbial biofilms, bacterial cells are encased in a self-produced matrix of polymers (e.g., exopolysaccharides) that enable surface adherence and protect against environmental stressors. For example, the wrinkly spreader phenotype of Pseudomonas fluorescens colonizes food/water sources and human tissue to form robust biofilms that can spread across surfaces. This biofilm largely consists of bacterial cellulose produced by the cellulose synthase proteins encoded by the wss operon, which also occurs in other species, including pathogenic Achromobacter species. Although phenotypic mutant analysis of the wssFGHI genes has previously shown that they are responsible for acetylation of bacterial cellulose, their specific roles remain unknown and distinct from the recently identified cellulose phosphoethanolamine modification found in other species. Here we have purified the C-terminal soluble form of WssI from P. fluorescens and A. insuavis and demonstrated acetyl-esterase activity with chromogenic substrates. The kinetic parameters (kcat/KM values of 13 and 8.0 M-1∙ s-1, respectively) indicate that these enzymes are up to four times more catalytically efficient than the closest characterized homolog, AlgJ from the alginate synthase. Unlike AlgJ and its cognate alginate polymer, WssI also demonstrated acetyltransferase activity onto cellulose oligomers (e.g., cellotetraose to cellohexaose) with multiple acetyl-donor substrates (pNP-Ac, MU-Ac and acetyl-CoA). Finally, a high-throughput screen identified three low micromolar WssI inhibitors that may be useful for chemically interrogating cellulose acetylation and biofilm formation.
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Affiliation(s)
| | - Emily Rodriguez
- Department of Biology, Wilfrid Laurier University, Waterloo, ON, Canada
| | - Shirley Constable
- Department of Biology, Wilfrid Laurier University, Waterloo, ON, Canada
| | - Brian Lowrance
- Department of Biology, Wilfrid Laurier University, Waterloo, ON, Canada
| | - Michael Fish
- Department of Biology, Wilfrid Laurier University, Waterloo, ON, Canada
| | - Joel T Weadge
- Department of Biology, Wilfrid Laurier University, Waterloo, ON, Canada.
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Moshynets OV, Baranovskyi TP, Cameron S, Iungin OS, Pokholenko I, Jerdan R, Kamyshnyi A, Krikunov AA, Potochilova VV, Rudnieva KL, Spiers AJ. Azithromycin possesses biofilm–inhibitory activity and potentiates non-bactericidal colistin methanesulfonate (CMS) and polymyxin B against Klebsiella pneumonia. PLoS One 2022; 17:e0270983. [PMID: 35776759 PMCID: PMC9249213 DOI: 10.1371/journal.pone.0270983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 06/21/2022] [Indexed: 11/30/2022] Open
Abstract
Novel antibiotic combinations may act synergistically to inhibit the growth of multidrug-resistant bacterial pathogens but predicting which combination will be successful is difficult, and standard antimicrobial susceptibility testing may not identify important physiological differences between planktonic free-swimming and biofilm-protected surface-attached sessile cells. Using a nominally macrolide-resistant model Klebsiella pneumoniae strain (ATCC 10031) we demonstrate the effectiveness of several macrolides in inhibiting biofilm growth in multi-well plates, and the ability of azithromycin (AZM) to improve the effectiveness of the antibacterial last-agent-of-choice for K. pneumoniae infections, colistin methanesulfonate (CMS), against biofilms. This synergistic action was also seen in biofilm tests of several K. pneumoniae hospital isolates and could also be identified in polymyxin B disc-diffusion assays on azithromycin plates. Our work highlights the complexity of antimicrobial-resistance in bacterial pathogens and the need to test antibiotics with biofilm models where potential synergies might provide new therapeutic opportunities not seen in liquid culture or colony-based assays.
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Affiliation(s)
- Olena V. Moshynets
- Institute of Molecular Biology and Genetics of the National Academy of Sciences of Ukraine, Kyiv, Ukraine
- * E-mail: (OVM); (AJS)
| | - Taras P. Baranovskyi
- Shupyk National Healthcare University of Ukraine, Kyiv, Ukraine
- Kyiv Regional Clinical Hospital, Kyiv, Ukraine
| | - Scott Cameron
- School of Applied Sciences, Abertay University, Dundee, United Kingdom
| | - Olga S. Iungin
- Institute of Molecular Biology and Genetics of the National Academy of Sciences of Ukraine, Kyiv, Ukraine
- Kyiv National University of Technologies and Design, Kyiv, Ukraine
| | - Ianina Pokholenko
- Institute of Molecular Biology and Genetics of the National Academy of Sciences of Ukraine, Kyiv, Ukraine
| | - Robyn Jerdan
- School of Applied Sciences, Abertay University, Dundee, United Kingdom
| | | | | | | | | | - Andrew J. Spiers
- School of Applied Sciences, Abertay University, Dundee, United Kingdom
- * E-mail: (OVM); (AJS)
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Moshynets OV, Baranovskyi TP, Iungin OS, Kysil NP, Metelytsia LO, Pokholenko I, Potochilova VV, Potters G, Rudnieva KL, Rymar SY, Semenyuta IV, Spiers AJ, Tarasyuk OP, Rogalsky SP. eDNA Inactivation and Biofilm Inhibition by the PolymericBiocide Polyhexamethylene Guanidine Hydrochloride (PHMG-Cl). Int J Mol Sci 2022; 23:ijms23020731. [PMID: 35054915 PMCID: PMC8775615 DOI: 10.3390/ijms23020731] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Revised: 01/03/2022] [Accepted: 01/03/2022] [Indexed: 01/05/2023] Open
Abstract
The choice of effective biocides used for routine hospital practice should consider the role of disinfectants in the maintenance and development of local resistome and how they might affect antibiotic resistance gene transfer within the hospital microbial population. Currently, there is little understanding of how different biocides contribute to eDNA release that may contribute to gene transfer and subsequent environmental retention. Here, we investigated how different biocides affect the release of eDNA from mature biofilms of two opportunistic model strains Pseudomonas aeruginosa ATCC 27853 (PA) and Staphylococcus aureus ATCC 25923 (SA) and contribute to the hospital resistome in the form of surface and water contaminants and dust particles. The effect of four groups of biocides, alcohols, hydrogen peroxide, quaternary ammonium compounds, and the polymeric biocide polyhexamethylene guanidine hydrochloride (PHMG-Cl), was evaluated using PA and SA biofilms. Most biocides, except for PHMG-Cl and 70% ethanol, caused substantial eDNA release, and PHMG-Cl was found to block biofilm development when used at concentrations of 0.5% and 0.1%. This might be associated with the formation of DNA–PHMG-Cl complexes as PHMG-Cl is predicted to bind to AT base pairs by molecular docking assays. PHMG-Cl was found to bind high-molecular DNA and plasmid DNA and continued to inactivate DNA on surfaces even after 4 weeks. PHMG-Cl also effectively inactivated biofilm-associated antibiotic resistance gene eDNA released by a pan-drug-resistant Klebsiella strain, which demonstrates the potential of a polymeric biocide as a new surface-active agent to combat the spread of antibiotic resistance in hospital settings.
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Affiliation(s)
- Olena V. Moshynets
- Biofilm Study Group, Department of Cell Regulatory Mechanisms, Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine, 150 Zabolotnoho Str., 03680 Kiev, Ukraine; (O.S.I.); (I.P.); (S.Y.R.)
- Correspondence: (O.V.M.); (S.P.R.)
| | - Taras P. Baranovskyi
- Department of Dermatovenerology, Allergology, Clinical and Laboratory Immunology, Shupyk National Healthcare University of Ukraine, 9 Dorohozhytska Str., 03680 Kiev, Ukraine;
- Kyiv Regional Clinical Hospital, 1 Baggovutivska Street, 04107 Kiev, Ukraine; (V.V.P.); (K.L.R.)
| | - Olga S. Iungin
- Biofilm Study Group, Department of Cell Regulatory Mechanisms, Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine, 150 Zabolotnoho Str., 03680 Kiev, Ukraine; (O.S.I.); (I.P.); (S.Y.R.)
- Department of Biotechnology, Leather and Fur, Faculty of Chemical and Biopharmaceutical Technologies, Kyiv National University of Technologies and Design, Nemyrovycha-Danchenka Street, 2, 01011 Kiev, Ukraine
| | - Nadiia P. Kysil
- National Children’s Specialized Hospital “Okhmatdyt”, 28/1 Chornovola Str., 01135 Kiev, Ukraine;
| | - Larysa O. Metelytsia
- V. P. Kukhar Institute of Bioorganic Chemistry and Petrochemistry, National Academy of Science of Ukraine, 50 Kharkivske Schose, 01135 Kiev, Ukraine; (L.O.M.); (I.V.S.); (O.P.T.)
| | - Ianina Pokholenko
- Biofilm Study Group, Department of Cell Regulatory Mechanisms, Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine, 150 Zabolotnoho Str., 03680 Kiev, Ukraine; (O.S.I.); (I.P.); (S.Y.R.)
| | - Viktoria V. Potochilova
- Kyiv Regional Clinical Hospital, 1 Baggovutivska Street, 04107 Kiev, Ukraine; (V.V.P.); (K.L.R.)
| | - Geert Potters
- Antwerp Maritime Academy, Noordkasteel Oost 6, 2030 Antwerp, Belgium;
- Department of Bioscience Engineering, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Kateryna L. Rudnieva
- Kyiv Regional Clinical Hospital, 1 Baggovutivska Street, 04107 Kiev, Ukraine; (V.V.P.); (K.L.R.)
| | - Svitlana Y. Rymar
- Biofilm Study Group, Department of Cell Regulatory Mechanisms, Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine, 150 Zabolotnoho Str., 03680 Kiev, Ukraine; (O.S.I.); (I.P.); (S.Y.R.)
| | - Ivan V. Semenyuta
- V. P. Kukhar Institute of Bioorganic Chemistry and Petrochemistry, National Academy of Science of Ukraine, 50 Kharkivske Schose, 01135 Kiev, Ukraine; (L.O.M.); (I.V.S.); (O.P.T.)
| | - Andrew J. Spiers
- School of Applied Sciences, Abertay University, Bell Street, Dundee DD1 1HG, UK;
| | - Oksana P. Tarasyuk
- V. P. Kukhar Institute of Bioorganic Chemistry and Petrochemistry, National Academy of Science of Ukraine, 50 Kharkivske Schose, 01135 Kiev, Ukraine; (L.O.M.); (I.V.S.); (O.P.T.)
| | - Sergiy P. Rogalsky
- V. P. Kukhar Institute of Bioorganic Chemistry and Petrochemistry, National Academy of Science of Ukraine, 50 Kharkivske Schose, 01135 Kiev, Ukraine; (L.O.M.); (I.V.S.); (O.P.T.)
- Correspondence: (O.V.M.); (S.P.R.)
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Moshynets O, Chernii S, Chernii V, Losytskyy M, Karakhim S, Czerwieniec R, Pekhnyo V, Yarmoluk S, Kovalska V. Fluorescent β-ketoenole AmyGreen dye for visualization of amyloid components of bacterial biofilms. Methods Appl Fluoresc 2020; 8:035006. [PMID: 32375137 DOI: 10.1088/2050-6120/ab90e0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Green-emitting water-soluble amino-ketoenole dye AmyGreen is proposed as an efficient fluorescent stain for visualization of bacterial amyloids in biofilms and the detection of pathological amyloids in vitro. This dye is almost non-fluorescent in solution, displays strong green emission in the presence of amyloid fibril of proteins. AmyGreen is also weakly fluorescent in presence to biomolecules that are components of cells, extracellular matrix or medium: nucleic acids, polysaccharides, lipids, and proteins. Thus, the luminescence turn-on behavior of AmyGreen can be utilized for visualization of amyloid components of bacterial biofilm extracellular matrix. Herein we report the application of AmyGreen for fluorescent staining of a number of amyloid-contained bacteria biofilms produced by Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Bordetella avium, and Staphylococcus aureus. The effectiveness of AmyGreen was compared to traditional amyloid sensitive dye Thioflavine T. The main advantage of AmyGreen (concentration 10-5 M) is a higher sensitivity in the visualization of amyloid biofilm components over Thioflavine T (10-4 M) as it was revealed when staining E. coli and K. pneumoniae bacterial biofilms. Besides, AmyGreen displays lower cross-selectivity to nucleic acids as demonstrated both in in-solution experiments and upon staining of eukaryotic human mesenchymal stem cells used as amyloid-free negative control over amyloid-rich bacterial biofilms. The results point to a lower risk of false-positive response upon determination of amyloid components of bacterial biofilm using AmyGreen. Co-staining of biofilm by AmyGreen and cellulose sensitive dye Calcofluor White show difference in their staining patterns and localization, indicating separation of polysaccharide-rich and amyloid-rich regions of investigated biofilms. Thus, we suggest the new AmyGreen stain for visualization and differentiation of amyloid fibrils in bacterial biofilms to be used solely and in combination with other stains for confocal and fluorescence microscopy analysis.
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Affiliation(s)
- Olena Moshynets
- Institute of Molecular Biology and Genetics NASU, 150 Zabolotnogo St., 03143 Kyiv, Ukraine
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Lavrenko A, Digtiar N, Gerasymenko N, Kaidashev I. A rare case of Bordetella avium pneumonia complicated by Raoultella planticola. Clin Case Rep 2020; 8:1039-1043. [PMID: 32577260 PMCID: PMC7303856 DOI: 10.1002/ccr3.2800] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 02/14/2020] [Accepted: 02/24/2020] [Indexed: 11/11/2022] Open
Abstract
Bordetella avium pneumonia immunocompromised the patient with subsequent complication by a rare opportunistic Raoultella planticola infection, which became a nosocomial pathogen in the healthcare setting.
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Affiliation(s)
- Anna Lavrenko
- Internal Medicine Department No. 3 with PhthisiologyUkrainian Medical Stomatological AcademyPoltavaUkraine
| | - Nataliia Digtiar
- Internal Medicine Department No. 3 with PhthisiologyUkrainian Medical Stomatological AcademyPoltavaUkraine
| | - Nataliia Gerasymenko
- Internal Medicine Department No. 3 with PhthisiologyUkrainian Medical Stomatological AcademyPoltavaUkraine
| | - Igor Kaidashev
- Internal Medicine Department No. 3 with PhthisiologyUkrainian Medical Stomatological AcademyPoltavaUkraine
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Moshynets O, Bardeau JF, Tarasyuk O, Makhno S, Cherniavska T, Dzhuzha O, Potters G, Rogalsky S. Antibiofilm Activity of Polyamide 11 Modified with Thermally Stable Polymeric Biocide Polyhexamethylene Guanidine 2-Naphtalenesulfonate. Int J Mol Sci 2019; 20:E348. [PMID: 30654458 PMCID: PMC6358945 DOI: 10.3390/ijms20020348] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Revised: 12/30/2018] [Accepted: 01/08/2019] [Indexed: 01/23/2023] Open
Abstract
The choice of efficient antimicrobial additives for polyamide resins is very difficult because of their high processing temperatures of up to 300 °C. In this study, a new, thermally stable polymeric biocide, polyhexamethylene guanidine 2-naphtalenesulfonate (PHMG-NS), was synthesised. According to thermogravimetric analysis, PHMG-NS has a thermal degradation point of 357 °C, confirming its potential use in joint melt processing with polyamide resins. Polyamide 11 (PA-11) films containing 5, 7 and 10 wt% of PHMG-NS were prepared by compression molding and subsequently characterised by FTIR spectroscopy. The surface properties were evaluated both by contact angle, and contactless induction. The incorporation of 10 wt% of PHMG-NS into PA-11 films was found to increase the positive surface charge density by almost two orders of magnitude. PA-11/PHMG-NS composites were found to have a thermal decomposition point at about 400 °C. Mechanical testing showed no change of the tensile strength of polyamide films containing PHMG-NS up to 7 wt%. Antibiofilm activity against the opportunistic bacteria Staphylococcus aureus and Escherichia coli was demonstrated for films containing 7 or 10 wt% of PHMG-NS, through a local biocide effect possibly based on an influence on the bacterial eDNA. The biocide hardly leached from the PA-11 matrix into water, at a rate of less than 1% from its total content for 21 days.
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Affiliation(s)
- Olena Moshynets
- Institute of Molecular Biology and Genetics of NAS of Ukraine, 03143 Kyiv, Ukraine.
| | - Jean-François Bardeau
- Institut des Molécules et Matériaux du Mans, UMR CNRS 6283, Université du Mans, 72085 Le Mans, France.
| | - Oksana Tarasyuk
- V. P. Kukhar Institute of Bioorganic Chemistry and Petrochemistry of NAS of Ukraine, 02160 Kyiv, Ukraine.
| | - Stanislav Makhno
- Chuiko Institute of Surface Chemistry of NAS of Ukraine, 03680 Kyiv, Ukraine.
| | - Tetiana Cherniavska
- Chuiko Institute of Surface Chemistry of NAS of Ukraine, 03680 Kyiv, Ukraine.
| | - Oleg Dzhuzha
- V. P. Kukhar Institute of Bioorganic Chemistry and Petrochemistry of NAS of Ukraine, 02160 Kyiv, Ukraine.
| | - Geert Potters
- Antwerp Maritime Academy, Noordkasteel Oost 6, 2030 Antwerp, Belgium.
- University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium.
| | - Sergiy Rogalsky
- V. P. Kukhar Institute of Bioorganic Chemistry and Petrochemistry of NAS of Ukraine, 02160 Kyiv, Ukraine.
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Koza A, Kusmierska A, McLaughlin K, Moshynets O, Spiers AJ. Adaptive radiation of Pseudomonas fluorescens SBW25 in experimental microcosms provides an understanding of the evolutionary ecology and molecular biology of A-L interface biofilm formation. FEMS Microbiol Lett 2018; 364:3850210. [PMID: 28535292 DOI: 10.1093/femsle/fnx109] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 05/22/2017] [Indexed: 12/17/2022] Open
Abstract
Combined experimental evolutionary and molecular biology approaches have been used to investigate the adaptive radiation of Pseudomonas fluorescens SBW25 in static microcosms leading to the colonisation of the air-liquid interface by biofilm-forming mutants such as the Wrinkly Spreader (WS). In these microcosms, the ecosystem engineering of the early wild-type colonists establishes the niche space for subsequent WS evolution and colonisation. Random WS mutations occurring in the developing population that deregulate diguanylate cyclases and c-di-GMP homeostasis result in cellulose-based biofilms at the air-liquid interface. These structures allow Wrinkly Spreaders to intercept O2 diffusing into the liquid column and limit the growth of competitors lower down. As the biofilm matures, competition increasingly occurs between WS lineages, and niche divergence within the biofilm may support further diversification before system failure when the structure finally sinks. A combination of pleiotropic and epistasis effects, as well as secondary mutations, may explain variations in WS phenotype and fitness. Understanding how mutations subvert regulatory networks to express intrinsic genome potential and key innovations providing a selective advantage in novel environments is key to understanding the versatility of bacteria, and how selection and ecological opportunity can rapidly lead to substantive changes in phenotype and in community structure and function.
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Affiliation(s)
- Anna Koza
- School of Science, Engineering and Technology, Abertay University, Dundee DD1 1HG, UK
| | - Anna Kusmierska
- School of Science, Engineering and Technology, Abertay University, Dundee DD1 1HG, UK
| | - Kimberley McLaughlin
- School of Science, Engineering and Technology, Abertay University, Dundee DD1 1HG, UK
| | - Olena Moshynets
- Institute of Molecular Biology and Genetics of the National Academy of Sciences of Ukraine, Kiev 03143, Ukraine
| | - Andrew J Spiers
- School of Science, Engineering and Technology, Abertay University, Dundee DD1 1HG, UK
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