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Hummels KR, Berry SP, Li Z, Taguchi A, Min JK, Walker S, Marks DS, Bernhardt TG. Coordination of bacterial cell wall and outer membrane biosynthesis. Nature 2023; 615:300-304. [PMID: 36859542 PMCID: PMC9995270 DOI: 10.1038/s41586-023-05750-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 01/23/2023] [Indexed: 03/03/2023]
Abstract
Gram-negative bacteria surround their cytoplasmic membrane with a peptidoglycan (PG) cell wall and an outer membrane (OM) with an outer leaflet composed of lipopolysaccharide (LPS)1. This complex envelope presents a formidable barrier to drug entry and is a major determinant of the intrinsic antibiotic resistance of these organisms2. The biogenesis pathways that build the surface are also targets of many of our most effective antibacterial therapies3. Understanding the molecular mechanisms underlying the assembly of the Gram-negative envelope therefore promises to aid the development of new treatments effective against the growing problem of drug-resistant infections. Although the individual pathways for PG and OM synthesis and assembly are well characterized, almost nothing is known about how the biogenesis of these essential surface layers is coordinated. Here we report the discovery of a regulatory interaction between the committed enzymes for the PG and LPS synthesis pathways in the Gram-negative pathogen Pseudomonas aeruginosa. We show that the PG synthesis enzyme MurA interacts directly and specifically with the LPS synthesis enzyme LpxC. Moreover, MurA was shown to stimulate LpxC activity in cells and in a purified system. Our results support a model in which the assembly of the PG and OM layers in many proteobacterial species is coordinated by linking the activities of the committed enzymes in their respective synthesis pathways.
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Affiliation(s)
- Katherine R Hummels
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Samuel P Berry
- Department of Systems Biology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Zhaoqi Li
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Atsushi Taguchi
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, Ibaraki, Japan
| | - Joseph K Min
- Department of Systems Biology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Suzanne Walker
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Debora S Marks
- Department of Systems Biology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Thomas G Bernhardt
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA.
- Howard Hughes Medical Institute, Boston, MA, USA.
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2
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Nguyen KT, Sugie J, Khanna K, Egan ME, Birkholz EA, Lee J, Beierschmitt C, Villa E, Pogliano J. Selective transport of fluorescent proteins into the phage nucleus. PLoS One 2021; 16:e0251429. [PMID: 34111132 PMCID: PMC8191949 DOI: 10.1371/journal.pone.0251429] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 04/26/2021] [Indexed: 11/18/2022] Open
Abstract
Upon infection of Pseudomonas cells, jumbo phages 201Φ2-1, ΦPA3, and ΦKZ assemble a phage nucleus. Viral DNA is enclosed within the phage-encoded proteinaceous shell along with proteins associated with DNA replication, recombination and transcription. Ribosomes and proteins involved in metabolic processes are excluded from the nucleus. RNA synthesis occurs inside the phage nucleus and messenger RNA is presumably transported into the cytoplasm to be translated. Newly synthesized proteins either remain in the cytoplasm or specifically translocate into the nucleus. The molecular mechanisms governing selective protein sorting and nuclear import in these phage infection systems are currently unclear. To gain insight into this process, we studied the localization of five reporter fluorescent proteins (GFP+, sfGFP, GFPmut1, mCherry, CFP). During infection with ΦPA3 or 201Φ2-1, all five fluorescent proteins were excluded from the nucleus as expected; however, we have discovered an anomaly with the ΦKZ nuclear transport system. The fluorescent protein GFPmut1, expressed by itself, was transported into the ΦKZ phage nucleus. We identified the amino acid residues on the surface of GFPmut1 required for nuclear targeting. Fusing GFPmut1 to any protein, including proteins that normally reside in the cytoplasm, resulted in transport of the fusion into the nucleus. Although the mechanism of transport is still unknown, we demonstrate that GFPmut1 is a useful tool that can be used for fluorescent labelling and targeting of proteins into the ΦKZ phage nucleus.
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Affiliation(s)
- Katrina T Nguyen
- Division of Biological Sciences, University of California San Diego, La Jolla, CA, United States of America
| | - Joseph Sugie
- Division of Biological Sciences, University of California San Diego, La Jolla, CA, United States of America
| | - Kanika Khanna
- Division of Biological Sciences, University of California San Diego, La Jolla, CA, United States of America
| | - MacKennon E Egan
- Division of Biological Sciences, University of California San Diego, La Jolla, CA, United States of America
| | - Erica A Birkholz
- Division of Biological Sciences, University of California San Diego, La Jolla, CA, United States of America
| | - Jina Lee
- Division of Biological Sciences, University of California San Diego, La Jolla, CA, United States of America
| | - Christopher Beierschmitt
- Division of Biological Sciences, University of California San Diego, La Jolla, CA, United States of America
| | - Elizabeth Villa
- Division of Biological Sciences, University of California San Diego, La Jolla, CA, United States of America
| | - Joe Pogliano
- Division of Biological Sciences, University of California San Diego, La Jolla, CA, United States of America
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3
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Min KB, Hwang W, Lee KM, Kim JB, Yoon SS. Chemical inhibitors of the conserved bacterial transcriptional regulator DksA1 suppressed quorum sensing-mediated virulence of Pseudomonas aeruginosa. J Biol Chem 2021; 296:100576. [PMID: 33757766 PMCID: PMC8081920 DOI: 10.1016/j.jbc.2021.100576] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 03/16/2021] [Accepted: 03/19/2021] [Indexed: 12/15/2022] Open
Abstract
Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen whose virulence is dependent on quorum sensing (QS). DksA1, an RNA polymerase-binding transcriptional regulator, plays a role in determining a number of phenotypes, including QS-mediated virulence. We therefore envisioned that DksA1 inhibitors may help to control P. aeruginosa infection. Here, we screened a library of 6970 chemical compounds and identified two compounds (henceforth termed Dkstatins) that specifically suppressed DksA1 activity. Treatment with these two compounds also substantially decreased the production of elastase and pyocyanin, dominant virulence determinants of P. aeruginosa, and protected murine hosts from lethal infection from a prototype strain of P. aeruginosa, PAO1. The Dkstatins also suppressed production of homoserine lactone (HSL)-based autoinducers that activate P. aeruginosa QS. The level of 3-oxo-C12-HSL produced by Dkstatin-treated wildtype PAO1 closely resembled that of the ΔdksA1 mutant. RNA-Seq analysis showed that transcription levels of QS- and virulence-associated genes were markedly reduced in Dkstatin-treated PAO1 cells, indicating that Dkstatin-mediated suppression occurs at the transcriptional level. Importantly, Dkstatins increased the antibiotic susceptibilities of PAO1, particularly to protein synthesis inhibitors, such as tobramycin and tetracycline. Co-immunoprecipitation assays demonstrated that these Dkstatins interfered with DksA1 binding to the β subunit of RNA polymerase, pointing to a potential mechanism of action. Collectively, our results illustrate that inhibition of P. aeruginosa QS may be achieved via DksA1 inhibitors and that Dkstatins may serve as potential lead compounds to control infection.
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Affiliation(s)
- Kyung Bae Min
- Department of Microbiology and Immunology, Yonsei University College of Medicine, Seoul, Korea; Brain Korea 21 PLUS Project for Medical Sciences, Yonsei University College of Medicine, Seoul, Korea
| | - Wontae Hwang
- Department of Microbiology and Immunology, Yonsei University College of Medicine, Seoul, Korea; Brain Korea 21 PLUS Project for Medical Sciences, Yonsei University College of Medicine, Seoul, Korea
| | - Kang-Mu Lee
- Department of Microbiology and Immunology, Yonsei University College of Medicine, Seoul, Korea
| | - June Beom Kim
- Department of Microbiology and Immunology, Yonsei University College of Medicine, Seoul, Korea; Brain Korea 21 PLUS Project for Medical Sciences, Yonsei University College of Medicine, Seoul, Korea
| | - Sang Sun Yoon
- Department of Microbiology and Immunology, Yonsei University College of Medicine, Seoul, Korea; Brain Korea 21 PLUS Project for Medical Sciences, Yonsei University College of Medicine, Seoul, Korea; Institute for Immunology and Immunological Diseases, Yonsei University College of Medicine, Seoul, Korea; Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Korea.
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4
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Koch MD, Fei C, Wingreen NS, Shaevitz JW, Gitai Z. Competitive binding of independent extension and retraction motors explains the quantitative dynamics of type IV pili. Proc Natl Acad Sci U S A 2021; 118:e2014926118. [PMID: 33593905 PMCID: PMC7923367 DOI: 10.1073/pnas.2014926118] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Type IV pili (TFP) function through cycles of extension and retraction. The coordination of these cycles remains mysterious due to a lack of quantitative measurements of multiple features of TFP dynamics. Here, we fluorescently label TFP in the pathogen Pseudomonas aeruginosa and track full extension and retraction cycles of individual filaments. Polymerization and depolymerization dynamics are stochastic; TFP are made at random times and extend, pause, and retract for random lengths of time. TFP can also pause for extended periods between two extension or two retraction events in both wild-type cells and a slowly retracting PilT mutant. We developed a biophysical model based on the stochastic binding of two dedicated extension and retraction motors to the same pilus machine that predicts the observed features of the data with no free parameters. We show that only a model in which both motors stochastically bind and unbind to the pilus machine independent of the piliation state of the machine quantitatively explains the experimentally observed pilus production rate. In experimental support of this model, we show that the abundance of the retraction motor dictates the pilus production rate and that PilT is bound to pilus machines even in their unpiliated state. Together, the strong quantitative agreement of our model with a variety of experiments suggests that the entire repetitive cycle of pilus extension and retraction is coordinated by the competition of stochastic motor binding to the pilus machine, and that the retraction motor is the major throttle for pilus production.
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Affiliation(s)
- Matthias D Koch
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08540
- Department of Molecular Biology, Princeton University, Princeton, NJ 08540
| | - Chenyi Fei
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08540
- Department of Molecular Biology, Princeton University, Princeton, NJ 08540
| | - Ned S Wingreen
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08540
- Department of Molecular Biology, Princeton University, Princeton, NJ 08540
| | - Joshua W Shaevitz
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08540;
- Joseph Henry Laboratories of Physics, Princeton University, Princeton, NJ 08540
| | - Zemer Gitai
- Department of Molecular Biology, Princeton University, Princeton, NJ 08540;
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5
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Molina-Mora JA, Chinchilla-Montero D, Castro-Peña C, García F. Two-dimensional gel electrophoresis (2D-GE) image analysis based on CellProfiler: Pseudomonas aeruginosa AG1 as model. Medicine (Baltimore) 2020; 99:e23373. [PMID: 33285719 PMCID: PMC7717798 DOI: 10.1097/md.0000000000023373] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Two-dimensional gel electrophoresis (2D-GE) is an indispensable technique for the study of proteomes of biological systems, providing an assessment of changes in protein abundance under various experimental conditions. However, due to the complexity of 2D-GE gels, there is no systematic, automatic, and reproducible protocol for image analysis and specific implementations are required for each context. In addition, practically all available solutions are commercial, which implies high cost and little flexibility to modulate the parameters of the algorithms. Using the bacterial strain, Pseudomonas aeruginosaAG1 as a model, we obtained images from 2D-GE of periplasmic protein profiles when the strain was exposed to multiple conditions, including antibiotics. Then, we proceeded to implement and evaluate an image analysis protocol with open-source software, CellProfiler. First, a preprocessing step included a bUnwarpJ-Image pipeline for aligning 2D-GE images. Then, using CellProfiler, we standardized two pipelines for spots identification. Total spots recognition was achieved using segmentation by intensity, whose performance was evaluated when compared with a reference protocol. In a second pipeline with the same program, differential identification of spots was addressed when comparing pairs of protein profiles. Due to the characteristics of the programs used, our workflow can automatically analyze a large number of images and it is parallelizable, which is an advantage with respect to other implementations. Finally, we compared six experimental conditions of bacterial strain in the presence or absence of antibiotics, determining protein profiles relationships by applying clustering algorithms PCA (Principal Components Analysis) and HC (Hierarchical Clustering).
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Azuama OC, Ortiz S, Quirós-Guerrero L, Bouffartigues E, Tortuel D, Maillot O, Feuilloley M, Cornelis P, Lesouhaitier O, Grougnet R, Boutefnouchet S, Wolfender JL, Chevalier S, Tahrioui A. Tackling Pseudomonas aeruginosa Virulence by Mulinane-Like Diterpenoids from Azorella atacamensis. Biomolecules 2020; 10:biom10121626. [PMID: 33276611 PMCID: PMC7761567 DOI: 10.3390/biom10121626] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 11/30/2020] [Accepted: 11/30/2020] [Indexed: 12/28/2022] Open
Abstract
Pseudomonas aeruginosa is an important multidrug-resistant human pathogen by dint of its high intrinsic, acquired, and adaptive resistance mechanisms, causing great concern for immune-compromised individuals and public health. Additionally, P. aeruginosa resilience lies in the production of a myriad of virulence factors, which are known to be tightly regulated by the quorum sensing (QS) system. Anti-virulence therapy has been adopted as an innovative alternative approach to circumvent bacterial antibiotic resistance. Since plants are known repositories of natural phytochemicals, herein, we explored the anti-virulence potential of Azorella atacamensis, a medicinal plant from the Taira Atacama community (Calama, Chile), against P. aeruginosa. Interestingly, A. atacamensis extract (AaE) conferred a significant protection for human lung cells and Caenorhabditis elegans nematodes towards P. aeruginosa pathogenicity. The production of key virulence factors was decreased upon AaE exposure without affecting P. aeruginosa growth. In addition, AaE was able to decrease QS-molecules production. Furthermore, metabolite profiling of AaE and its derived fractions achieved by combination of a molecular network and in silico annotation allowed the putative identification of fourteen diterpenoids bearing a mulinane-like skeleton. Remarkably, this unique interesting group of diterpenoids seems to be responsible for the interference with virulence factors as well as on the perturbation of membrane homeostasis of P. aeruginosa. Hence, there was a significant increase in membrane stiffness, which appears to be modulated by the cell wall stress response ECFσ SigX, an extracytoplasmic function sigma factor involved in membrane homeostasis as well as P. aeruginosa virulence.
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Affiliation(s)
- Onyedikachi Cecil Azuama
- Laboratoire de Microbiologie Signaux et Microenvironnement, Normandie Université, Université de Rouen Normandie, LMSM EA4312, 27000 Évreux, France; (O.C.A.); (E.B.); (D.T.); (O.M.); (M.F.); (P.C.); (O.L.); (S.C.)
- Fédération de Recherche Sécurité Sanitaire, Bien-Être, Aliments Durables (SéSAD), Normandie Université, Université de Rouen Normandie, 27000 Évreux, France
- Department of Biological Sciences, Alex-Ekwueme Federal University, Ndufu Alike Ikwo PMB1010, Nigeria
| | - Sergio Ortiz
- Équipe Produits Naturels, Analyses et Synthèses (PNAS), CiTCoM UMR 8038 CNRS, Faculté de Pharmacie, Université de Paris, 75006 Paris, France; (S.O.); (R.G.); (S.B.)
| | - Luis Quirós-Guerrero
- Phytochemistry and Bioactive Natural Products, School of Pharmaceutical Science, University of Geneva, 1211 Geneva, Switzerland; (L.Q.-G.); (J.-L.W.)
- Institute of Pharmaceutical Sciences of Western Switzerland (ISPSW), University of Geneva, CMU, 1211 Geneva, Switzerland
| | - Emeline Bouffartigues
- Laboratoire de Microbiologie Signaux et Microenvironnement, Normandie Université, Université de Rouen Normandie, LMSM EA4312, 27000 Évreux, France; (O.C.A.); (E.B.); (D.T.); (O.M.); (M.F.); (P.C.); (O.L.); (S.C.)
- Fédération de Recherche Sécurité Sanitaire, Bien-Être, Aliments Durables (SéSAD), Normandie Université, Université de Rouen Normandie, 27000 Évreux, France
| | - Damien Tortuel
- Laboratoire de Microbiologie Signaux et Microenvironnement, Normandie Université, Université de Rouen Normandie, LMSM EA4312, 27000 Évreux, France; (O.C.A.); (E.B.); (D.T.); (O.M.); (M.F.); (P.C.); (O.L.); (S.C.)
- Fédération de Recherche Sécurité Sanitaire, Bien-Être, Aliments Durables (SéSAD), Normandie Université, Université de Rouen Normandie, 27000 Évreux, France
| | - Olivier Maillot
- Laboratoire de Microbiologie Signaux et Microenvironnement, Normandie Université, Université de Rouen Normandie, LMSM EA4312, 27000 Évreux, France; (O.C.A.); (E.B.); (D.T.); (O.M.); (M.F.); (P.C.); (O.L.); (S.C.)
- Fédération de Recherche Sécurité Sanitaire, Bien-Être, Aliments Durables (SéSAD), Normandie Université, Université de Rouen Normandie, 27000 Évreux, France
| | - Marc Feuilloley
- Laboratoire de Microbiologie Signaux et Microenvironnement, Normandie Université, Université de Rouen Normandie, LMSM EA4312, 27000 Évreux, France; (O.C.A.); (E.B.); (D.T.); (O.M.); (M.F.); (P.C.); (O.L.); (S.C.)
- Fédération de Recherche Sécurité Sanitaire, Bien-Être, Aliments Durables (SéSAD), Normandie Université, Université de Rouen Normandie, 27000 Évreux, France
| | - Pierre Cornelis
- Laboratoire de Microbiologie Signaux et Microenvironnement, Normandie Université, Université de Rouen Normandie, LMSM EA4312, 27000 Évreux, France; (O.C.A.); (E.B.); (D.T.); (O.M.); (M.F.); (P.C.); (O.L.); (S.C.)
- Fédération de Recherche Sécurité Sanitaire, Bien-Être, Aliments Durables (SéSAD), Normandie Université, Université de Rouen Normandie, 27000 Évreux, France
| | - Olivier Lesouhaitier
- Laboratoire de Microbiologie Signaux et Microenvironnement, Normandie Université, Université de Rouen Normandie, LMSM EA4312, 27000 Évreux, France; (O.C.A.); (E.B.); (D.T.); (O.M.); (M.F.); (P.C.); (O.L.); (S.C.)
- Fédération de Recherche Sécurité Sanitaire, Bien-Être, Aliments Durables (SéSAD), Normandie Université, Université de Rouen Normandie, 27000 Évreux, France
| | - Raphaël Grougnet
- Équipe Produits Naturels, Analyses et Synthèses (PNAS), CiTCoM UMR 8038 CNRS, Faculté de Pharmacie, Université de Paris, 75006 Paris, France; (S.O.); (R.G.); (S.B.)
| | - Sabrina Boutefnouchet
- Équipe Produits Naturels, Analyses et Synthèses (PNAS), CiTCoM UMR 8038 CNRS, Faculté de Pharmacie, Université de Paris, 75006 Paris, France; (S.O.); (R.G.); (S.B.)
| | - Jean-Luc Wolfender
- Phytochemistry and Bioactive Natural Products, School of Pharmaceutical Science, University of Geneva, 1211 Geneva, Switzerland; (L.Q.-G.); (J.-L.W.)
- Institute of Pharmaceutical Sciences of Western Switzerland (ISPSW), University of Geneva, CMU, 1211 Geneva, Switzerland
| | - Sylvie Chevalier
- Laboratoire de Microbiologie Signaux et Microenvironnement, Normandie Université, Université de Rouen Normandie, LMSM EA4312, 27000 Évreux, France; (O.C.A.); (E.B.); (D.T.); (O.M.); (M.F.); (P.C.); (O.L.); (S.C.)
- Fédération de Recherche Sécurité Sanitaire, Bien-Être, Aliments Durables (SéSAD), Normandie Université, Université de Rouen Normandie, 27000 Évreux, France
| | - Ali Tahrioui
- Laboratoire de Microbiologie Signaux et Microenvironnement, Normandie Université, Université de Rouen Normandie, LMSM EA4312, 27000 Évreux, France; (O.C.A.); (E.B.); (D.T.); (O.M.); (M.F.); (P.C.); (O.L.); (S.C.)
- Fédération de Recherche Sécurité Sanitaire, Bien-Être, Aliments Durables (SéSAD), Normandie Université, Université de Rouen Normandie, 27000 Évreux, France
- Correspondence: ; Tel.: +33-232291560; Fax: +33-232291550
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Linklater DP, Baulin VA, Le Guével X, Fleury JB, Hanssen E, Nguyen THP, Juodkazis S, Bryant G, Crawford RJ, Stoodley P, Ivanova EP. Antibacterial Action of Nanoparticles by Lethal Stretching of Bacterial Cell Membranes. Adv Mater 2020; 32:e2005679. [PMID: 33179362 DOI: 10.1002/adma.202005679] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 10/05/2020] [Indexed: 06/11/2023]
Abstract
It is commonly accepted that nanoparticles (NPs) can kill bacteria; however, the mechanism of antimicrobial action remains obscure for large NPs that cannot translocate the bacterial cell wall. It is demonstrated that the increase in membrane tension caused by the adsorption of NPs is responsible for mechanical deformation, leading to cell rupture and death. A biophysical model of the NP-membrane interactions is presented which suggests that adsorbed NPs cause membrane stretching and squeezing. This general phenomenon is demonstrated experimentally using both model membranes and Pseudomonas aeruginosa and Staphylococcus aureus, representing Gram-positive and Gram-negative bacteria. Hydrophilic and hydrophobic quasi-spherical and star-shaped gold (Au)NPs are synthesized to explore the antibacterial mechanism of non-translocating AuNPs. Direct observation of nanoparticle-induced membrane tension and squeezing is demonstrated using a custom-designed microfluidic device, which relieves contraction of the model membrane surface area and eventual lipid bilayer collapse. Quasi-spherical nanoparticles exhibit a greater bactericidal action due to a higher interactive affinity, resulting in greater membrane stretching and rupturing, corroborating the theoretical model. Electron microscopy techniques are used to characterize the NP-bacterial-membrane interactions. This combination of experimental and theoretical results confirm the proposed mechanism of membrane-tension-induced (mechanical) killing of bacterial cells by non-translocating NPs.
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Affiliation(s)
- Denver P Linklater
- School of Science, RMIT University, P.O. Box 2476, Melbourne, Victoria, 3001, Australia
- Opical Sciences Centre, Swinburne University of Technology, Hawthorn, Victoria, 3122, Australia
| | - Vladimir A Baulin
- Department d'Enginyeria Quimica, Universitat Rovira i Virgili, 26 Av. dels Paisos Catalans, Tarragona, 43007, Spain
| | - Xavier Le Guével
- Insitute for Advanced Biosciences, University Grenoble-Alpes, Allee des Alpes, La Tronche, 38700, France
| | - Jean-Baptiste Fleury
- Experimental Physics and Center for Biophysics, Saarland University, Saarbrücken, 66123, Germany
| | - Eric Hanssen
- Ian Holmes Imaging Centre, Bio21 Institute, University of Melbourne, 30 Flemington Rd, Parkville, Victoria, 3010, Australia
| | - The Hong Phong Nguyen
- Faculty of Applied Sciences, Ton Duc Thang University, Ho Chi Minh City, 700000, Vietnam
| | - Saulius Juodkazis
- Opical Sciences Centre, Swinburne University of Technology, Hawthorn, Victoria, 3122, Australia
| | - Gary Bryant
- School of Science, RMIT University, P.O. Box 2476, Melbourne, Victoria, 3001, Australia
| | - Russell J Crawford
- School of Science, RMIT University, P.O. Box 2476, Melbourne, Victoria, 3001, Australia
| | - Paul Stoodley
- Infectious Diseases Institute, The Ohio State University, 716 Biomedical Research Tower, 460 West 12th Avenue, Columbus, OH, 43210, USA
- National Centre for Advanced Tribology at Southampton (nCATS), National Biofilm Innovation Centre (NBIC), Mechanical Engineering, University of Southampton, Southampton, SO17 1Bj, UK
| | - Elena P Ivanova
- School of Science, RMIT University, P.O. Box 2476, Melbourne, Victoria, 3001, Australia
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Khan F, Lee JW, Javaid A, Park SK, Kim YM. Inhibition of biofilm and virulence properties of Pseudomonas aeruginosa by sub-inhibitory concentrations of aminoglycosides. Microb Pathog 2020; 146:104249. [PMID: 32418905 DOI: 10.1016/j.micpath.2020.104249] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 03/19/2020] [Accepted: 05/04/2020] [Indexed: 02/06/2023]
Abstract
Aminoglycosides are a commonly used class of antibiotics; however, their application has been discontinued due to the emergence of multi-drug resistance bacterial strains. In the present study, the subinhibitory concentrations (sub-MIC) of several aminoglycosides were determined and tested as an antibiofilm and for their anti-virulence properties against Pseudomonas aeruginosa PAO1, which is an opportunistic foodborne pathogen. P. aeruginosa PAO1 exhibits multiple mechanisms of resistance, including the formation of biofilm and production of several virulence factors, against aminoglycoside antibiotics. The sub-MIC of these antibiotics exhibited biofilm inhibition of P. aeruginosa in alkaline TSB (pH 7.9). Moreover, various concentrations of these aminoglycosides also eradicate the mature biofilm of P. aeruginosa. In the presence of sub-MIC of aminoglycosides, the morphological changes of P. aeruginosa were found to change from rod-shaped to the filamentous, elongated, and streptococcal forms. Similar growth conditions and sub-MIC of aminoglycosides were also found to attenuate several virulence properties of P. aeruginosa PAO1. Molecular docking studies demonstrate that these aminoglycosides possess strong binding properties with the LasR protein, which is a well-characterized quorum-sensing receptor of P. aeruginosa. The present study suggests a new approach to revitalize aminoglycosides as antibiofilm and antivirulence drugs to treat infections caused by pathogenic bacteria.
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Affiliation(s)
- Fazlurrahman Khan
- Institute of Food Science, Pukyong National University, Busan, 48513, South Korea
| | - Jang-Won Lee
- Department of Food Science and Technology, Pukyong National University, Busan, 48513, South Korea
| | - Aqib Javaid
- Department of Biotechnology, School of Engineering and Technology, Sharda University, Greater Noida, 201306, UP, India
| | - Seul-Ki Park
- Institute of Food Science, Pukyong National University, Busan, 48513, South Korea
| | - Young-Mog Kim
- Institute of Food Science, Pukyong National University, Busan, 48513, South Korea; Department of Food Science and Technology, Pukyong National University, Busan, 48513, South Korea.
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9
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Perraud Q, Cantero P, Roche B, Gasser V, Normant VP, Kuhn L, Hammann P, Mislin GLA, Ehret-Sabatier L, Schalk IJ. Phenotypic Adaption of Pseudomonas aeruginosa by Hacking Siderophores Produced by Other Microorganisms. Mol Cell Proteomics 2020; 19:589-607. [PMID: 32024770 PMCID: PMC7124469 DOI: 10.1074/mcp.ra119.001829] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 12/23/2019] [Indexed: 12/31/2022] Open
Abstract
Bacteria secrete siderophores to access iron, a key nutrient poorly bioavailable and the source of strong competition between microorganisms in most biotopes. Many bacteria also use siderophores produced by other microorganisms (exosiderophores) in a piracy strategy. Pseudomonas aeruginosa, an opportunistic pathogen, produces two siderophores, pyoverdine and pyochelin, and is also able to use a panel of exosiderophores. We first investigated expression of the various iron-uptake pathways of P. aeruginosa in three different growth media using proteomic and RT-qPCR approaches and observed three different phenotypic patterns, indicating complex phenotypic plasticity in the expression of the various iron-uptake pathways. We then investigated the phenotypic plasticity of iron-uptake pathway expression in the presence of various exosiderophores (present individually or as a mixture) under planktonic growth conditions, as well as in an epithelial cell infection assay. In all growth conditions tested, catechol-type exosiderophores were clearly more efficient in inducing the expression of their corresponding transporters than the others, showing that bacteria opt for the use of catechol siderophores to access iron when they are present in the environment. In parallel, expression of the proteins of the pyochelin pathway was significantly repressed under most conditions tested, as well as that of proteins of the pyoverdine pathway, but to a lesser extent. There was no effect on the expression of the heme and ferrous uptake pathways. Overall, these data provide precise insights on how P. aeruginosa adjusts the expression of its various iron-uptake pathways (phenotypic plasticity and switching) to match varying levels of iron and competition.
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Affiliation(s)
- Quentin Perraud
- Université de Strasbourg, UMR7242, ESBS, Bld Sébastien Brant, F-67413 Illkirch, Strasbourg, France; CNRS, UMR7242, ESBS, Bld Sébastien Brant, F-67413 Illkirch, Strasbourg, France
| | - Paola Cantero
- Laboratoire de Spectrométrie de Masse BioOrganique, Université de Strasbourg, CNRS, IPHC UMR 7178, F-67000 Strasbourg, France
| | - Béatrice Roche
- Université de Strasbourg, UMR7242, ESBS, Bld Sébastien Brant, F-67413 Illkirch, Strasbourg, France; CNRS, UMR7242, ESBS, Bld Sébastien Brant, F-67413 Illkirch, Strasbourg, France
| | - Véronique Gasser
- Université de Strasbourg, UMR7242, ESBS, Bld Sébastien Brant, F-67413 Illkirch, Strasbourg, France; CNRS, UMR7242, ESBS, Bld Sébastien Brant, F-67413 Illkirch, Strasbourg, France
| | - Vincent P Normant
- Université de Strasbourg, UMR7242, ESBS, Bld Sébastien Brant, F-67413 Illkirch, Strasbourg, France; CNRS, UMR7242, ESBS, Bld Sébastien Brant, F-67413 Illkirch, Strasbourg, France
| | - Lauriane Kuhn
- Plateforme Proteomique Strasbourg - Esplanade, Institut de Biologie Moléculaire et Cellulaire, CNRS, FR1589, 15 rue Descartes, F-67084 Strasbourg Cedex, France
| | - Philippe Hammann
- Plateforme Proteomique Strasbourg - Esplanade, Institut de Biologie Moléculaire et Cellulaire, CNRS, FR1589, 15 rue Descartes, F-67084 Strasbourg Cedex, France
| | - Gaëtan L A Mislin
- Université de Strasbourg, UMR7242, ESBS, Bld Sébastien Brant, F-67413 Illkirch, Strasbourg, France; CNRS, UMR7242, ESBS, Bld Sébastien Brant, F-67413 Illkirch, Strasbourg, France
| | - Laurence Ehret-Sabatier
- Laboratoire de Spectrométrie de Masse BioOrganique, Université de Strasbourg, CNRS, IPHC UMR 7178, F-67000 Strasbourg, France
| | - Isabelle J Schalk
- Université de Strasbourg, UMR7242, ESBS, Bld Sébastien Brant, F-67413 Illkirch, Strasbourg, France; CNRS, UMR7242, ESBS, Bld Sébastien Brant, F-67413 Illkirch, Strasbourg, France.
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10
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Nicastro GG, Kaihami GH, Pulschen AA, Hernandez-Montelongo J, Boechat AL, de Oliveira Pereira T, Rosa CGT, Stefanello E, Colepicolo P, Bordi C, Baldini RL. c-di-GMP-related phenotypes are modulated by the interaction between a diguanylate cyclase and a polar hub protein. Sci Rep 2020; 10:3077. [PMID: 32080219 PMCID: PMC7033161 DOI: 10.1038/s41598-020-59536-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 01/30/2020] [Indexed: 01/19/2023] Open
Abstract
c-di-GMP is a major player in the switch between biofilm and motile lifestyles. Several bacteria exhibit a large number of c-di-GMP metabolizing proteins, thus a fine-tuning of this nucleotide levels may occur. It is hypothesized that some c-di-GMP metabolizing proteins would provide the global c-di-GMP levels inside the cell whereas others would maintain a localized pool, with the resulting c-di-GMP acting at the vicinity of its production. Although attractive, this hypothesis has yet to be demonstrated in Pseudomonas aeruginosa. We found that the diguanylate cyclase DgcP interacts with the cytosolic region of FimV, a polar peptidoglycan-binding protein involved in type IV pilus assembly. Moreover, DgcP is located at the cell poles in wild type cells but scattered in the cytoplasm of cells lacking FimV. Overexpression of dgcP leads to the classical phenotypes of high c-di-GMP levels (increased biofilm and impaired motilities) in the wild-type strain, but not in a ΔfimV background. Therefore, our findings suggest that DgcP activity is regulated by FimV. The polar localization of DgcP might contribute to a local c-di-GMP pool that can be sensed by other proteins at the cell pole, bringing to light a specialized function for a specific diguanylate cyclase.
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Affiliation(s)
- Gianlucca G Nicastro
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Gilberto H Kaihami
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - André A Pulschen
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Jacobo Hernandez-Montelongo
- Instituto de Física "Gleb Wataghin", Universidade Estadual de Campinas, Campinas, Brazil
- Departamento de Ciencias Matemáticas y Físicas, Facultad de Ingeniería, Universidad Católica de Temuco, Temuco, Chile
| | - Ana Laura Boechat
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | | | - Caio Gomes Tavares Rosa
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Eliezer Stefanello
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Pio Colepicolo
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | | | - Regina L Baldini
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil.
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11
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Abstract
Biofilm formation by bacteria protects them against environmental stresses such as desiccation, shear forces and antimicrobial agents, making them much harder to remove and increasing their virulence and persistence in industrial water systems and biomedical equipment. One promising method of disrupting biofilm formation and growth is to employ passive surface structures to inhibit bacterial adhesion and aggregation. However, most studies thus far have mainly focused on the early stages of biofilm formation and it is unclear if the influence of surface topography in the early phase will propagate to later stages. Here, we attempt to address this with an investigation into the biofilm formation of Pseudomonas aeruginosa on 25 different nanograting geometries, with dimensions that were systematically varied from subcellular to cellular sizes. The biofilms were characterized from the exponential growth phase to the decline phase, in intervals of 24 H over 4 days, using confocal scanning laser microscopy. Comparing the maximum volume of biofilm formed on each surface over 96 H, it was found that approximately 1/3 of the nanograting geometries exhibited 72 ± 16 % lower biovolume density than a flat surface. Bacteria on these nanogratings were also observed to form 40 ± 11 % smaller microcolonies that were 17 ± 6 % less compact than that found on the control surface. The majority of these nanogratings had deep trenches (i.e. depth ≥ 70% of the cell diameter). Furthermore, P. aeruginosa cells were observed to multiply at approximately twice the rate on almost all the nanogratings compared to flat surfaces, but these cell populations also began to decline 24 H earlier than those on a flat surface. Using available literature on P. aeruginosa, a qualitative model was put forth, attributing the results to increased cell motility, decreased exopolysaccharide formation and disrupted psl adhesin/signal trails on nanogratings. These factors, together, led to the net effects of reduced attachment, increased scattering of cells and rapid decline of the biofilms on nanogratings. The insights derived from this study suggest that passive surface geometries can be designed and optimized to successfully control/inhibit biofilm formation and growth.
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12
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Prakash P, Abdulla AZ, Singh V, Varma M. Tuning the torque-speed characteristics of the bacterial flagellar motor to enhance swimming speed. Phys Rev E 2019; 100:062609. [PMID: 31962428 DOI: 10.1103/physreve.100.062609] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Indexed: 06/10/2023]
Abstract
In a classic paper, Purcell [Proc. Natl. Acad. Sci. U. S. A. 94, 11307 (1997)10.1073/pnas.94.21.11307] analyzed the dynamics of flagellated bacterial swimmers and derived a geometrical relationship which maximizes the propulsion efficiency. Experimental measurements for wild-type bacterial species E. coli have revealed that they closely satisfy this geometric optimality. However, dependence of the flagellar motor speed on the load and more generally the role of the torque-speed characteristics of the flagellar motor are not considered in Purcell's original analysis. Here we derive a tuned condition representing a match between the flagella geometry and the torque-speed characteristics of the flagellar motor to maximize the bacterial swimming speed for a given load. This condition is independent of the geometric optimality condition derived by Purcell. Interestingly, this condition is not satisfied by wild-type E. coli which swims 2-3 times slower than the maximum possible speed given the amount of available motor torque. Finally, we present experimental data on swimming dynamics of a cargo laden bacterial system which follows our analytical model. Our analysis also reveals the existence of an anomalous propulsion regime where the swim speed increases with increasing load (drag).
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Affiliation(s)
- Praneet Prakash
- Centre for Nanoscience and Engineering, Indian Institute of Science, Bangalore 560012, India
| | - Amith Z Abdulla
- Department of Physics, Indian Institute of Science, Bangalore 560012, India
| | - Varsha Singh
- Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore 560012, India
| | - Manoj Varma
- Centre for Nanoscience and Engineering, Indian Institute of Science, Bangalore 560012, India
- Robert Bosch Centre for Cyber Physical Systems, Indian Institute of Science, Bangalore 560012, India
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13
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Cao Y, Jana S, Bowen L, Tan X, Liu H, Rostami N, Brown J, Jakubovics NS, Chen J. Hierarchical Rose Petal Surfaces Delay the Early-Stage Bacterial Biofilm Growth. Langmuir 2019; 35:14670-14680. [PMID: 31630525 DOI: 10.1021/acs.langmuir.9b02367] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A variety of natural surfaces exhibit antibacterial properties; as a result, significant efforts in the past decade have been dedicated toward fabrication of biomimetic surfaces that can help control biofilm growth. Examples of such surfaces include rose petals, which possess hierarchical structures like the micropapillae measuring tens of microns and nanofolds that range in the size of 700 ± 100 nm. We duplicated the natural structures on rose petal surfaces via a simple UV-curable nanocasting technique and tested the efficacy of these artificial surfaces in preventing biofilm growth using clinically relevant bacteria strains. The rose petal-structured surfaces exhibited hydrophobicity (contact angle (CA) ≈ 130.8° ± 4.3°) and high CA hysteresis (∼91.0° ± 4.9°). Water droplets on rose petal replicas evaporated following the constant contact line mode, indicating the likely coexistence of both Cassie and Wenzel states (Cassie-Baxter impregnating the wetting state). Fluorescence microscopy and image analysis revealed the significantly lower attachment of Staphylococcus epidermidis (86.1 ± 6.2% less) and Pseudomonas aeruginosa (85.9 ± 3.2% less) on the rose petal-structured surfaces, compared with flat surfaces over a period of 2 h. An extensive biofilm matrix was observed in biofilms formed by both species on flat surfaces after prolonged growth (several days), but was less apparent on rose petal-biomimetic surfaces. In addition, the biomass of S. epidermidis (63.2 ± 9.4% less) and P. aeruginosa (76.0 ± 10.0% less) biofilms were significantly reduced on the rose petal-structured surfaces, in comparison to the flat surfaces. By comparing P. aeruginosa growth on representative unitary nanopillars, we demonstrated that hierarchical structures are more effective in delaying biofilm growth. The mechanisms are two-fold: (1) the nanofolds across the hemispherical micropapillae restrict initial attachment of bacterial cells and delay the direct contact of cells via cell alignment and (2) the hemispherical micropapillae arrays isolate bacterial clusters and inhibit the formation of a fibrous network. The hierarchical features on rose petal surfaces may be useful for developing strategies to control biofilm formation in medical and industrial contexts.
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Affiliation(s)
| | | | - Leon Bowen
- Department of Physics , Durham University , Durham DH1 3LE , U.K
| | | | - Hongzhong Liu
- School of Mechanical Engineering , Xi'an Jiaotong University , Xi'an 710054 , China
| | - Nadia Rostami
- School of Dental Sciences , Newcastle University , Newcastle Upon Tyne NE2 4BW , U.K
| | - James Brown
- Centre for Biomolecular Sciences , University of Nottingham , Nottingham NG7 2RD , U.K
| | - Nicholas S Jakubovics
- School of Dental Sciences , Newcastle University , Newcastle Upon Tyne NE2 4BW , U.K
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14
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Kaplan M, Subramanian P, Ghosal D, Oikonomou CM, Pirbadian S, Starwalt‐Lee R, Mageswaran SK, Ortega DR, Gralnick JA, El‐Naggar MY, Jensen GJ. In situ imaging of the bacterial flagellar motor disassembly and assembly processes. EMBO J 2019; 38:e100957. [PMID: 31304634 PMCID: PMC6627242 DOI: 10.15252/embj.2018100957] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 04/11/2019] [Accepted: 04/18/2019] [Indexed: 11/09/2022] Open
Abstract
The self-assembly of cellular macromolecular machines such as the bacterial flagellar motor requires the spatio-temporal synchronization of gene expression with proper protein localization and association of dozens of protein components. In Salmonella and Escherichia coli, a sequential, outward assembly mechanism has been proposed for the flagellar motor starting from the inner membrane, with the addition of each new component stabilizing the previous one. However, very little is known about flagellar disassembly. Here, using electron cryo-tomography and sub-tomogram averaging of intact Legionella pneumophila, Pseudomonas aeruginosa, and Shewanella oneidensis cells, we study flagellar motor disassembly and assembly in situ. We first show that motor disassembly results in stable outer membrane-embedded sub-complexes. These sub-complexes consist of the periplasmic embellished P- and L-rings, and bend the membrane inward while it remains apparently sealed. Additionally, we also observe various intermediates of the assembly process including an inner-membrane sub-complex consisting of the C-ring, MS-ring, and export apparatus. Finally, we show that the L-ring is responsible for reshaping the outer membrane, a crucial step in the flagellar assembly process.
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Affiliation(s)
- Mohammed Kaplan
- Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaCAUSA
| | - Poorna Subramanian
- Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaCAUSA
| | - Debnath Ghosal
- Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaCAUSA
| | - Catherine M Oikonomou
- Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaCAUSA
| | - Sahand Pirbadian
- Department of Physics and Astronomy, Biological Sciences, and ChemistryUniversity of Southern CaliforniaLos AngelesCAUSA
| | - Ruth Starwalt‐Lee
- BioTechnology InstituteUniversity of Minnesota – Twin CitiesSt. PaulMNUSA
| | | | - Davi R Ortega
- Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaCAUSA
| | - Jeffrey A Gralnick
- BioTechnology InstituteUniversity of Minnesota – Twin CitiesSt. PaulMNUSA
- Department of Plant and Microbial BiologyUniversity of Minnesota – Twin CitiesSt. PaulMNUSA
| | - Mohamed Y El‐Naggar
- Department of Physics and Astronomy, Biological Sciences, and ChemistryUniversity of Southern CaliforniaLos AngelesCAUSA
| | - Grant J Jensen
- Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaCAUSA
- Howard Hughes Medical InstituteCalifornia Institute of TechnologyPasadenaCAUSA
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15
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Xia A, Yang S, Zhang R, Ni L, Xing X, Jin F. Imaging the Separation Distance between the Attached Bacterial Cells and the Surface with a Total Internal Reflection Dark-Field Microscope. Langmuir 2019; 35:8860-8866. [PMID: 31194567 DOI: 10.1021/acs.langmuir.9b01378] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The attachment of bacterial cells to a surface is implicated in the formation of biofilms. Although the surface-related behaviors in this process, such as single cell motility and surface sensing, have been investigated intensively, the precise information of separation distance between the attached cells and the surface has remained unclear. Here, we set a prism-based total internal reflection dark-field microscope (p-TIRDFM) combined with the microfluidic method to image the separation distance of single attached cells. We directly observed that bacterial cells attached to the surface with one nearest touchpoint, and it gradually changed to two touchpoints, respectively, for the two offspring with the cell division. We first monitored the fluctuation of the relative distance on nanometer scale when cells twitch on a surface and further established the relationship between the twitching velocity and the separation distance. The results indicated that the moving cells are a considerable distance apart from the surface and the separation distance fluctuated more widely than immobile cells.
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16
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Zhu S, Schniederberend M, Zhitnitsky D, Jain R, Galán JE, Kazmierczak BI, Liu J. In Situ Structures of Polar and Lateral Flagella Revealed by Cryo-Electron Tomography. J Bacteriol 2019; 201:e00117-19. [PMID: 31010901 PMCID: PMC6560136 DOI: 10.1128/jb.00117-19] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 04/16/2019] [Indexed: 02/07/2023] Open
Abstract
The bacterial flagellum is a sophisticated self-assembling nanomachine responsible for motility in many bacterial pathogens, including Pseudomonas aeruginosa, Vibrio spp., and Salmonella enterica The bacterial flagellum has been studied extensively in the model systems Escherichia coli and Salmonella enterica serovar Typhimurium, yet the range of variation in flagellar structure and assembly remains incompletely understood. Here, we used cryo-electron tomography and subtomogram averaging to determine in situ structures of polar flagella in P. aeruginosa and peritrichous flagella in S Typhimurium, revealing notable differences between these two flagellar systems. Furthermore, we observed flagellar outer membrane complexes as well as many incomplete flagellar subassemblies, which provide additional insight into mechanisms underlying flagellar assembly and loss in both P. aeruginosa and S Typhimurium.IMPORTANCE The bacterial flagellum has evolved as one of the most sophisticated self-assembled molecular machines, which confers locomotion and is often associated with virulence of bacterial pathogens. Variation in species-specific features of the flagellum, as well as in flagellar number and placement, results in structurally distinct flagella that appear to be adapted to the specific environments that bacteria encounter. Here, we used cutting-edge imaging techniques to determine high-resolution in situ structures of polar flagella in Pseudomonas aeruginosa and peritrichous flagella in Salmonella enterica serovar Typhimurium, demonstrating substantial variation between flagella in these organisms. Importantly, we observed novel flagellar subassemblies and provided additional insight into the structural basis of flagellar assembly and loss in both P. aeruginosa and S Typhimurium.
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Affiliation(s)
- Shiwei Zhu
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, USA
- Microbial Sciences Institute, Yale University, West Haven, Connecticut, USA
| | - Maren Schniederberend
- Department of Medicine (Infectious Diseases), Yale University School of Medicine, New Haven, Connecticut, USA
| | - Daniel Zhitnitsky
- Department of Medicine (Infectious Diseases), Yale University School of Medicine, New Haven, Connecticut, USA
| | - Ruchi Jain
- Department of Medicine (Infectious Diseases), Yale University School of Medicine, New Haven, Connecticut, USA
| | - Jorge E Galán
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Barbara I Kazmierczak
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, USA
- Department of Medicine (Infectious Diseases), Yale University School of Medicine, New Haven, Connecticut, USA
| | - Jun Liu
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, USA
- Microbial Sciences Institute, Yale University, West Haven, Connecticut, USA
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17
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Soler-Arango J, Figoli C, Muraca G, Bosch A, Brelles-Mariño G. The Pseudomonas aeruginosa biofilm matrix and cells are drastically impacted by gas discharge plasma treatment: A comprehensive model explaining plasma-mediated biofilm eradication. PLoS One 2019; 14:e0216817. [PMID: 31233528 PMCID: PMC6590783 DOI: 10.1371/journal.pone.0216817] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 04/28/2019] [Indexed: 12/21/2022] Open
Abstract
Biofilms are microbial communities encased in a protective matrix composed of exopolymeric substances including exopolysaccharides, proteins, lipids, and extracellular DNA. Biofilms cause undesirable effects such as biofouling, equipment damage, prostheses colonization, and disease. Biofilms are also more resilient than free-living cells to regular decontamination methods and therefore, alternative methods are needed to eradicate them. The use of non-thermal atmospheric pressure plasmas is a good alternative as plasmas contain reactive species, free radicals, and UV photons well-known for their decontamination potential against free microorganisms. Pseudomonas aeruginosa biofilms colonize catheters, indwelling devices, and prostheses. Plasma effects on cell viability have been previously documented for P. aeruginosa biofilms. Nonetheless, the effect of plasma on the biofilm matrix has received less attention and there is little evidence regarding the changes the matrix undergoes. The aim of this work was to study the effect plasma exerts mostly on the P. aeruginosa biofilm matrix and to expand the existing knowledge about its effect on sessile cells in order to achieve a better understanding of the mechanism/s underlying plasma-mediated biofilm inactivation. We report a reduction in the amount of the biofilm matrix, the loss of its tridimensional structure, and morphological changes in sessile cells at long exposure times. We show chemical and structural changes on the biofilm matrix (mostly on carbohydrates and eDNA) and cells (mostly on proteins and lipids) that are more profound with longer plasma exposure times. We also demonstrate the presence of lipid oxidation products confirming cell membrane lipid peroxidation as plasma exposure time increases. To our knowledge this is the first report providing detailed evidence of the variety of chemical and structural changes that occur mostly on the biofilm matrix and sessile cells as a consequence of the plasma treatment. Based on our results, we propose a comprehensive model explaining plasma-mediated biofilm inactivation.
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Affiliation(s)
- Juliana Soler-Arango
- Biofilm Eradication Laboratory, Center for Research and Development of Industrial Fermentations, Consejo Nacional de Investigaciones Científicas y Técnicas (CINDEFI, CCT-LA PLATA-CONICET), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Cecilia Figoli
- Bioespectroscopy Laboratory, Center for Research and Development of Industrial Fermentations, Consejo Nacional de Investigaciones Científicas y Técnicas (CINDEFI, CCT-LA PLATA-CONICET), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Giuliana Muraca
- Biofilm Eradication Laboratory, Center for Research and Development of Industrial Fermentations, Consejo Nacional de Investigaciones Científicas y Técnicas (CINDEFI, CCT-LA PLATA-CONICET), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Alejandra Bosch
- Bioespectroscopy Laboratory, Center for Research and Development of Industrial Fermentations, Consejo Nacional de Investigaciones Científicas y Técnicas (CINDEFI, CCT-LA PLATA-CONICET), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina
- * E-mail: (AB); (GBM)
| | - Graciela Brelles-Mariño
- Biofilm Eradication Laboratory, Center for Research and Development of Industrial Fermentations, Consejo Nacional de Investigaciones Científicas y Técnicas (CINDEFI, CCT-LA PLATA-CONICET), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina
- * E-mail: (AB); (GBM)
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18
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Liaqat I, Liaqat M, Tahir HM, Haq I, Ali NM, Arshad M, Arshad N. Motility effects biofilm formation in Pseudomonas aeruginosa and Enterobacter cloacae. Pak J Pharm Sci 2019; 32:927-932. [PMID: 31278701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Chronic infections caused by gram negative bacteria are the mains reasons to have morbidity and death in patients, despite using high doses of antibiotics applied to cure diseases producing by them. This study was designed to identify the role of flagella in biofilm formation Ten pure strains were collected from our lab. Morphological variation and motility assays led us to study two strains in detail. They were characterized biochemically, physiologically and genetically. Biofilm formation analysis was performed using test tube assay, congo red assay and liquid-interface coverslip assay. In order to disrupt flagella of studied strains, blending was induced for 5, 10 and 15 minutes followed by centrifugation and observing motility using motility test. Biofilm quantification of wild type (parental) and blended strains was done using test tube and liquid interface coverslip assays. 16S rRNA sequencing identified strains as Pseudomonas aeroginosa and Enterobacter cloacae. Significant biofilm formation (p>0.05) by was observed after 72 and 18 hours using test tube and liquid-interface coverslip assays respectively. Flagellar disruption showed that 15 minutes blending caused significant reduction in both strains, hence demonstrated that flagellar mediated motility could be a potent strategy to stabilize aggregate and invest resources for biofilm formation in P. aeruginosa and E. cloacae.
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Affiliation(s)
- Iram Liaqat
- Department of Zoology, Govt. College University, Lahore, Pakistan
| | - Mishal Liaqat
- Department of Zoology, Govt. Model Town College for Women, Lahore, Pakistan
| | | | - Ikramul Haq
- Institute of Industrial Biotechnology (IIBT), Govt. College University, Lahore, Pakistan
| | | | - Muhammad Arshad
- Department of Zoology, University of Education, Lahore, Pakistan
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19
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Cooke AC, Nello AV, Ernst RK, Schertzer JW. Analysis of Pseudomonas aeruginosa biofilm membrane vesicles supports multiple mechanisms of biogenesis. PLoS One 2019; 14:e0212275. [PMID: 30763382 PMCID: PMC6375607 DOI: 10.1371/journal.pone.0212275] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 01/30/2019] [Indexed: 01/07/2023] Open
Abstract
Outer Membrane Vesicles (OMVs) are ubiquitous in bacterial environments and enable interactions within and between species. OMVs are observed in lab-grown and environmental biofilms, but our understanding of their function comes primarily from planktonic studies. Planktonic OMVs assist in toxin delivery, cell-cell communication, horizontal gene transfer, small RNA trafficking, and immune system evasion. Previous studies reported differences in size and proteomic cargo between planktonic and agar plate biofilm OMVs, suggesting possible differences in function between OMV types. In Pseudomonas aeruginosa interstitial biofilms, extracellular vesicles were reported to arise through cell lysis, in contrast to planktonic OMV biogenesis that involves the Pseudomonas Quinolone Signal (PQS) without appreciable autolysis. Differences in biogenesis mechanism could provide a rationale for observed differences in OMV characteristics between systems. Using nanoparticle tracking, we found that P. aeruginosa PAO1 planktonic and biofilm OMVs had similar characteristics. However, P. aeruginosa PA14 OMVs were smaller, with planktonic OMVs also being smaller than their biofilm counterparts. Large differences in Staphylococcus killing ability were measured between OMVs from different strains, and a smaller within-strain difference was recorded between PA14 planktonic and biofilm OMVs. Across all conditions, the predatory ability of OMVs negatively correlated with their size. To address biogenesis mechanism, we analyzed vesicles from wild type and pqsA mutant biofilms. This showed that PQS is required for physiological-scale production of biofilm OMVs, and time-course analysis confirmed that PQS production precedes OMV production as it does in planktonic cultures. However, a small sub-population of vesicles was detected in pqsA mutant biofilms whose size distribution more resembled sonicated cell debris than wild type OMVs. These results support the idea that, while a small and unique population of vesicles in P. aeruginosa biofilms may result from cell lysis, the PQS-induced mechanism is required to generate the majority of OMVs produced by wild type communities.
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Affiliation(s)
- Adam C. Cooke
- Department of Biological Sciences, Binghamton University, Binghamton, New York, United States of America
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, New York, United States of America
| | - Alexander V. Nello
- Department of Biological Sciences, Binghamton University, Binghamton, New York, United States of America
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, New York, United States of America
| | - Robert K. Ernst
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, Maryland, United States of America
| | - Jeffrey W. Schertzer
- Department of Biological Sciences, Binghamton University, Binghamton, New York, United States of America
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, New York, United States of America
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Muthuramalingam M, White JC, Murphy T, Ames JR, Bourne CR. The toxin from a ParDE toxin-antitoxin system found in Pseudomonas aeruginosa offers protection to cells challenged with anti-gyrase antibiotics. Mol Microbiol 2019; 111:441-454. [PMID: 30427086 PMCID: PMC6368863 DOI: 10.1111/mmi.14165] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/25/2018] [Indexed: 12/13/2022]
Abstract
Toxin-antitoxin systems are mediators of diverse activities in bacterial physiology. For the ParE-type toxins, their reported role of gyrase inhibition utilized during plasmid-segregation killing indicates they are toxic. However, their location throughout chromosomes leads to questions about function, including potential non-toxic outcomes. The current study has characterized a ParDE system from the opportunistic human pathogen Pseudomonas aeruginosa (Pa). We identified a protective function for this ParE toxin, PaParE, against effects of quinolone and other antibiotics. However, higher concentrations of PaParE are themselves toxic to cells, indicating the phenotypic outcome can vary based on its concentration. Our assays confirmed PaParE inhibition of gyrase-mediated supercoiling of DNA with an IC50 value in the low micromolar range, a species-specificity that resulted in more efficacious inhibition of Escherichia coli derived gyrase versus Pa gyrase, and overexpression in the absence of antitoxin yielded an expected filamentous morphology with multi-foci nucleic acid material. Additional data revealed that the PaParE toxin is monomeric and interacts with dimeric PaParD antitoxin with a KD in the lower picomolar range, yielding a heterotetramer. This work provides novel insights into chromosome-encoded ParE function, whereby its expression can impart partial protection to cultures from selected antibiotics.
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Affiliation(s)
- Meenakumari Muthuramalingam
- The University of Oklahoma, Department of Chemistry and BiochemistryNorman73019OKUSA
- Present address:
Department of Pharmaceutical ChemistryUniversity of KansasLawrence66047 KSUSA
| | - John C. White
- The University of Oklahoma, Department of Chemistry and BiochemistryNorman73019OKUSA
| | - Tamiko Murphy
- The University of Oklahoma, Department of Chemistry and BiochemistryNorman73019OKUSA
| | - Jessica R. Ames
- The University of Oklahoma, Department of Chemistry and BiochemistryNorman73019OKUSA
| | - Christina R. Bourne
- The University of Oklahoma, Department of Chemistry and BiochemistryNorman73019OKUSA
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21
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Fila G, Krychowiak M, Rychlowski M, Bielawski KP, Grinholc M. Antimicrobial blue light photoinactivation of Pseudomonas aeruginosa: Quorum sensing signaling molecules, biofilm formation and pathogenicity. J Biophotonics 2018; 11:e201800079. [PMID: 29952074 DOI: 10.1002/jbio.201800079] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Accepted: 06/26/2018] [Indexed: 06/08/2023]
Abstract
Pseudomonas aeruginosa is a common causative bacterium of acute and chronic infections that have been responsible for high mortality over the past decade. P. aeruginosa produces many virulence factors such as toxins, enzymes and dyes that are strongly dependent on quorum sensing (QS) signaling systems. P. aeruginosa has three major QS systems (las, rhl and Pseudomonas quinolone signal) that regulate the expression of genes encoding virulence factors as well as biofilm production and maturation. Antimicrobial blue light (aBL) is considered a therapeutic option for bacterial infections and has other benefits, such as reducing bacterial virulence. Therefore, this study investigated the efficacy of aBL to reduce P. aeruginosa pathogenicity. aBL treatment resulted in the reduced activity of certain QS signaling molecules in P. aeruginosa and inhibited biofilm formation. in vivo tests using a Caenorhabditis elegans infection model indicated that sublethal aBL decreased the pathogenicity of P. aeruginosa. aBL may be a new virulence-targeting therapeutic approach.
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Affiliation(s)
- Grzegorz Fila
- Laboratory of Molecular Diagnostics, Department of Biotechnology, Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdansk, Poland
| | - Marta Krychowiak
- Laboratory of Biologically Active Compounds, Department of Biotechnology, Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdansk, Poland
| | - Michal Rychlowski
- Laboratory of Virus Molecular Biology, Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdansk, Poland
| | - Krzysztof Piotr Bielawski
- Laboratory of Molecular Diagnostics, Department of Biotechnology, Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdansk, Poland
| | - Mariusz Grinholc
- Laboratory of Molecular Diagnostics, Department of Biotechnology, Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdansk, Poland
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Vimalnath S, Ravishankar H, Schwandt C, Kumar RV, Subramanian S. Mechanistic studies on the biosorption of Pb(II) by Pseudomonas aeruginosa. Water Sci Technol 2018; 78:290-300. [PMID: 30101764 DOI: 10.2166/wst.2018.296] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The biosorption of Pb(II) ions from aqueous solution has been studied using both the intact and thermolyzed cells of Pseudomonas aeruginosa. Further, the role of the major cell wall components, namely DNA, protein, polysaccharide, and lipid, in Pb(II) binding has been assessed using an enzymatic treatment method. The Pb(II) bioremediation capability of P. aeruginosa cells has been investigated by varying the parameters of pH, time of interaction, amount of biomass, and concentration of Pb(II). The complete bioremoval of Pb(II) using intact cells has been achieved for an initial Pb(II) concentration of 12.4 mg L-1 at pH 6.2 and temperature 29 ± 1 °C. The biosorption isotherm follows Langmuirian behavior with a Gibbs free energy of -30.7 kJ mol-1, indicative of chemisorption. The biosorption kinetics is consistent with a pseudo-second-order model. The possible Pb(II) binding mechanisms of P. aeruginosa cells are discussed based on characterization using zeta potential measurements, Fourier transform infra-red spectroscopy, and energy dispersive X-ray spectroscopy. The results confirm that among the major cell wall components studied, polysaccharide shows the highest contribution towards Pb(II) binding, followed by DNA, lipid, and protein. Similar studies using thermolyzed cells show higher Pb(II) uptake compared to the intact cells both before and after enzymatic treatment.
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Affiliation(s)
- S Vimalnath
- Department of Materials Engineering, Indian Institute of Science, Bangalore 560012, India E-mail:
| | - H Ravishankar
- Department of Materials Engineering, Indian Institute of Science, Bangalore 560012, India E-mail:
| | - C Schwandt
- Department of Materials Science & Metallurgy, University of Cambridge, Cambridge CB3 0FS, UK
| | - R V Kumar
- Department of Materials Science & Metallurgy, University of Cambridge, Cambridge CB3 0FS, UK
| | - S Subramanian
- Department of Materials Engineering, Indian Institute of Science, Bangalore 560012, India E-mail:
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23
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Zuttion F, Ligeour C, Vidal O, Wälte M, Morvan F, Vidal S, Vasseur JJ, Chevolot Y, Phaner-Goutorbe M, Schillers H. The anti-adhesive effect of glycoclusters on Pseudomonas aeruginosa bacteria adhesion to epithelial cells studied by AFM single cell force spectroscopy. Nanoscale 2018; 10:12771-12778. [PMID: 29946584 DOI: 10.1039/c8nr03285h] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The human opportunistic pathogen Pseudomonas aeruginosa (PA) is responsible for chronic infections of the respiratory epithelium in cystic fibrosis patients. PA takes advantage of an arsenal of virulence factors to infect and colonize human lungs. Among them, the lectin LecA favours epithelium invasion by interacting with host cell globotriaosylceramide (Gb3). A new therapeutic approach is based on the development of synthetic multivalent molecules (glycoclusters) targeting LecA with a higher affinity than its natural ligand. Atomic force microscopy-single cell force spectroscopy has been used to study the effect of glycoclusters on the bacteria-cell interaction. Glycoclusters have been shown to affect the detachment work and detachment force of the bacteria-cell interaction. The specificity and the efficiency of the glycocluster in targeting the lectin and destabilizing the PA-epithelial cell adhesion are demonstrated and discussed.
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Affiliation(s)
- Francesca Zuttion
- Université de Lyon, Ecole Centrale de Lyon, Institut des Nanotechnologies de Lyon INL UMR-5270, CNRS, 36 avenue Guy de Collongue, 69134 Ecully, France.
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24
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Abstract
Delivery of cargo to target cells is fundamental to bacterial competitiveness. One important but poorly understood system, ubiquitous among Gram-negative organisms, involves packaging cargo into outer membrane vesicles (OMVs). These biological nanoparticles are involved in processes ranging from toxin delivery to cell-cell communication. Despite this, we know comparatively little about how OMVs are formed. Building upon the discovery that the Pseudomonas Quinolone Signal (PQS) stimulates OMV biogenesis in Pseudomonas aeruginosa, we proposed a model where PQS interacts with the outer membrane to induce curvature and ultimately OMV formation. Though this model is well supported in P. aeruginosa, it remained unclear whether other organisms produce similar compounds. Here we describe the development of a tightly controlled experimental system to test the interaction of bacterially-produced factors with target cells. Using this system, we show that multiple species respond to PQS by increasing OMV formation, that PQS accumulates in the induced vesicles, and that other bacteria secrete OMV-promoting factors. Analysis of induced vesicles indicates that recipient-mediated mechanisms exist to control vesicle size and that relatedness to the producer organism can dictate susceptibility to OMV-inducing compounds. This work provides evidence that small molecule induced OMV biogenesis is a widely conserved process and that cross-talk between systems may influence OMV production in neighboring bacteria.
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Affiliation(s)
- Alexander M Horspool
- Department of Biological Sciences, Binghamton University, Binghamton, New York, USA
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, New York, USA
| | - Jeffrey W Schertzer
- Department of Biological Sciences, Binghamton University, Binghamton, New York, USA.
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, New York, USA.
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25
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Ohlsson P, Petersson K, Augustsson P, Laurell T. Acoustic impedance matched buffers enable separation of bacteria from blood cells at high cell concentrations. Sci Rep 2018; 8:9156. [PMID: 29904138 PMCID: PMC6002537 DOI: 10.1038/s41598-018-25551-0] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 04/19/2018] [Indexed: 12/03/2022] Open
Abstract
Sepsis is a common and often deadly systemic response to an infection, usually caused by bacteria. The gold standard for finding the causing pathogen in a blood sample is blood culture, which may take hours to days. Shortening the time to diagnosis would significantly reduce mortality. To replace the time-consuming blood culture we are developing a method to directly separate bacteria from red and white blood cells to enable faster bacteria identification. The blood cells are moved from the sample flow into a parallel stream using acoustophoresis. Due to their smaller size, the bacteria are not affected by the acoustic field and therefore remain in the blood plasma flow and can be directed to a separate outlet. When optimizing for sample throughput, 1 ml of undiluted whole blood equivalent can be processed within 12.5 min, while maintaining the bacteria recovery at 90% and the blood cell removal above 99%. That makes this the fastest label-free microfluidic continuous flow method per channel to separate bacteria from blood with high bacteria recovery (>80%). The high throughput was achieved by matching the acoustic impedance of the parallel stream to that of the blood sample, to avoid that acoustic forces relocate the fluid streams.
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Affiliation(s)
- Pelle Ohlsson
- Departament of Biomedical Engineering, Lund University, Lund, Sweden.
| | - Klara Petersson
- Departament of Biomedical Engineering, Lund University, Lund, Sweden
| | - Per Augustsson
- Departament of Biomedical Engineering, Lund University, Lund, Sweden
| | - Thomas Laurell
- Departament of Biomedical Engineering, Lund University, Lund, Sweden.
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26
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Spalding C, Keen E, Smith DJ, Krachler AM, Jabbari S. Mathematical modelling of the antibiotic-induced morphological transition of Pseudomonas aeruginosa. PLoS Comput Biol 2018; 14:e1006012. [PMID: 29481562 PMCID: PMC5843380 DOI: 10.1371/journal.pcbi.1006012] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 03/08/2018] [Accepted: 01/31/2018] [Indexed: 11/18/2022] Open
Abstract
Here we formulate a mechanistic mathematical model to describe the growth dynamics of P. aeruginosa in the presence of the β-lactam antibiotic meropenem. The model is mechanistic in the sense that carrying capacity is taken into account through the dynamics of nutrient availability rather than via logistic growth. In accordance with our experimental results we incorporate a sub-population of cells, differing in morphology from the normal bacillary shape of P. aeruginosa bacteria, which we assume have immunity from direct antibiotic action. By fitting this model to experimental data we obtain parameter values that give insight into the growth of a bacterial population that includes different cell morphologies. The analysis of two parameters sets, that produce different long term behaviour, allows us to manipulate the system theoretically in order to explore the advantages of a shape transition that may potentially be a mechanism that allows P. aeruginosa to withstand antibiotic effects. Our results suggest that inhibition of this shape transition may be detrimental to bacterial growth and thus suggest that the transition may be a defensive mechanism implemented by bacterial machinery. In addition to this we provide strong theoretical evidence for the potential therapeutic strategy of using antimicrobial peptides (AMPs) in combination with meropenem. This proposed combination therapy exploits the shape transition as AMPs induce cell lysis by forming pores in the cytoplasmic membrane, which becomes exposed in the spherical cells. Antimicrobial resistance is an urgent global health threat and it is critical that we formulate alternative treatment strategies to combat bacterial infections. To do this we must understand how bacteria respond to currently used antibiotics. Pseudomonas aeruginosa is the leading cause of death among cystic fibrosis patients, a top cause of hospital-acquired infections in the UK and is currently listed as a critical priority in a list of antibiotic-resistant bacteria produced by the World Health Organisation. P. aeruginosa can change shape in the presence of certain antibiotics that work by targeting cell wall synthesis. The bacteria make the reversible transition from the native rod shape to a fragile spherical shape by shedding the cell wall and in doing so they evade the effects of the antibiotic. We formulate a system of equations that describes the growth of the bacteria including the shape transition we witness when we add antibiotic. Fitting this model to experimental data, we obtain parameter values that we then vary to make predictions on how inhibiting the shape transition or increasing the death rate of spherical cells would affect the overall bacterial growth. These predictions can support suitable combination therapies and hint towards alternative treatment strategies.
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Affiliation(s)
- Chloe Spalding
- School of Mathematics, University of Birmingham, Edgbaston Campus, Birmingham, United Kingdom
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston Campus, Birmingham, United Kingdom
- * E-mail: (CS); (SJ)
| | - Emma Keen
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston Campus, Birmingham, United Kingdom
| | - David J. Smith
- School of Mathematics, University of Birmingham, Edgbaston Campus, Birmingham, United Kingdom
- Institute for Metabolism and Systems Research, University of Birmingham, Edgbaston Campus, Birmingham, United Kingdom
| | - Anne-Marie Krachler
- Department of Microbiology and Molecular Genetics, University of Texas McGovern Medical School at Houston, Houston, Texas, United States of America
| | - Sara Jabbari
- School of Mathematics, University of Birmingham, Edgbaston Campus, Birmingham, United Kingdom
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston Campus, Birmingham, United Kingdom
- * E-mail: (CS); (SJ)
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27
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Elamin AA, Steinicke S, Oehlmann W, Braun Y, Wanas H, Shuralev EA, Huck C, Maringer M, Rohde M, Singh M. Novel drug targets in cell wall biosynthesis exploited by gene disruption in Pseudomonas aeruginosa. PLoS One 2017; 12:e0186801. [PMID: 29045498 PMCID: PMC5646862 DOI: 10.1371/journal.pone.0186801] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 10/06/2017] [Indexed: 01/01/2023] Open
Abstract
For clinicians, Pseudomonas aeruginosa is a nightmare pathogen that is one of the top three causes of opportunistic human infections. Therapy of P. aeruginosa infections is complicated due to its natural high intrinsic resistance to antibiotics. Active efflux and decreased uptake of drugs due to cell wall/membrane permeability appear to be important issues in the acquired antibiotic tolerance mechanisms. Bacterial cell wall biosynthesis enzymes have been shown to be essential for pathogenicity of Gram-negative bacteria. However, the role of these targets in virulence has not been identified in P. aeruginosa. Here, we report knockout (k.o) mutants of six cell wall biosynthesis targets (murA, PA4450; murD, PA4414; murF, PA4416; ppiB, PA1793; rmlA, PA5163; waaA, PA4988) in P. aeruginosa PAO1, and characterized these in order to find out whether these genes and their products contribute to pathogenicity and virulence of P. aeruginosa. Except waaA k.o, deletion of cell wall biosynthesis targets significantly reduced growth rate in minimal medium compared to the parent strain. The k.o mutants showed exciting changes in cell morphology and colonial architectures. Remarkably, ΔmurF cells became grossly enlarged. Moreover, the mutants were also attenuated in vivo in a mouse infection model except ΔmurF and ΔwaaA and proved to be more sensitive to macrophage-mediated killing than the wild-type strain. Interestingly, the deletion of the murA gene resulted in loss of virulence activity in mice, and the virulence was restored in a plant model by unknown mechanism. This study demonstrates that cell wall targets contribute significantly to intracellular survival, in vivo growth, and pathogenesis of P. aeruginosa. In conclusion, these findings establish a link between cell wall targets and virulence of P. aeruginosa and thus may lead to development of novel drugs for the treatment of P. aeruginosa infection.
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Affiliation(s)
| | | | - Wulf Oehlmann
- LIONEX Diagnostics and Therapeutics GmbH, Braunschweig, Germany
| | - Yvonne Braun
- LIONEX Diagnostics and Therapeutics GmbH, Braunschweig, Germany
| | - Hanaa Wanas
- LIONEX Diagnostics and Therapeutics GmbH, Braunschweig, Germany
| | - Eduard A. Shuralev
- Institute of Environmental Sciences, Kazan Federal University, Kazan, Tatarstan, Russian Federation
- Central Research Laboratory, Kazan State Medical Academy – Branch Campus of the FSBEI FPE RMACPE MOH Russia, Kazan, Tatarstan, Russian Federation
| | | | | | - Manfred Rohde
- Central Facility for Microscopy, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Mahavir Singh
- LIONEX Diagnostics and Therapeutics GmbH, Braunschweig, Germany
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28
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de Anda J, Lee EY, Lee CK, Bennett RR, Ji X, Soltani S, Harrison MC, Baker AE, Luo Y, Chou T, O’Toole GA, Armani AM, Golestanian R, Wong GCL. High-Speed "4D" Computational Microscopy of Bacterial Surface Motility. ACS Nano 2017; 11:9340-9351. [PMID: 28836761 PMCID: PMC5978429 DOI: 10.1021/acsnano.7b04738] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Bacteria exhibit surface motility modes that play pivotal roles in early-stage biofilm community development, such as type IV pili-driven "twitching" motility and flagellum-driven "spinning" and "swarming" motility. Appendage-driven motility is controlled by molecular motors, and analysis of surface motility behavior is complicated by its inherently 3D nature, the speed of which is too fast for confocal microscopy to capture. Here, we combine electromagnetic field computation and statistical image analysis to generate 3D movies close to a surface at 5 ms time resolution using conventional inverted microscopes. We treat each bacterial cell as a spherocylindrical lens and use finite element modeling to solve Maxwell's equations and compute the diffracted light intensities associated with different angular orientations of the bacterium relative to the surface. By performing cross-correlation calculations between measured 2D microscopy images and a library of computed light intensities, we demonstrate that near-surface 3D movies of Pseudomonas aeruginosa translational and rotational motion are possible at high temporal resolution. Comparison between computational reconstructions and detailed hydrodynamic calculations reveals that P. aeruginosa act like low Reynolds number spinning tops with unstable orbits, driven by a flagellum motor with a torque output of ∼2 pN μm. Interestingly, our analysis reveals that P. aeruginosa can undergo complex flagellum-driven dynamical behavior, including precession, nutation, and an unexpected taxonomy of surface motility mechanisms, including upright-spinning bacteria that diffuse laterally across the surface, and horizontal bacteria that follow helicoidal trajectories and exhibit superdiffusive movements parallel to the surface.
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Affiliation(s)
- Jaime de Anda
- Department of Bioengineering, Department of Chemistry and Biochemistry, and California NanoSystems Institute, University of California Los Angeles, Los Angeles, California 90095-1600, United States
| | - Ernest Y. Lee
- Department of Bioengineering, Department of Chemistry and Biochemistry, and California NanoSystems Institute, University of California Los Angeles, Los Angeles, California 90095-1600, United States
| | - Calvin K. Lee
- Department of Bioengineering, Department of Chemistry and Biochemistry, and California NanoSystems Institute, University of California Los Angeles, Los Angeles, California 90095-1600, United States
| | - Rachel R. Bennett
- Department of Physics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
- Rudolf Peierls Centre for Theoretical Physics, University of Oxford, Oxford OX1 3NP, U.K
| | - Xiang Ji
- Department of Physics, University of California San Diego, La Jolla, California 92093, United States
| | - Soheil Soltani
- Mork Family Department of Chemical Engineering and Materials Sciences, University of Southern California, Los Angeles, California 90089, United States
| | - Mark C. Harrison
- Mork Family Department of Chemical Engineering and Materials Sciences, University of Southern California, Los Angeles, California 90089, United States
| | - Amy E. Baker
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire 03755, United States
| | - Yun Luo
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire 03755, United States
- DuPont Industrial Biosciences, Wilmington, Delaware 19803, United States
| | - Tom Chou
- Departments of Biomathematics and Mathematics, University of California Los Angeles, Los Angeles, California 90095-1766, United States
| | - George A. O’Toole
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire 03755, United States
| | - Andrea M. Armani
- Mork Family Department of Chemical Engineering and Materials Sciences, University of Southern California, Los Angeles, California 90089, United States
| | - Ramin Golestanian
- Rudolf Peierls Centre for Theoretical Physics, University of Oxford, Oxford OX1 3NP, U.K
| | - Gerard C. L. Wong
- Department of Bioengineering, Department of Chemistry and Biochemistry, and California NanoSystems Institute, University of California Los Angeles, Los Angeles, California 90095-1600, United States
- Corresponding Author: Tel: (310) 794-7684.
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29
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Ali-Ahmad A, Bornet O, Fadel F, Bourne Y, Vincent F, Bordi C, Guerlesquin F, Sebban-Kreuzer C. NMR assignments of the GacS histidine-kinase periplasmic detection domain from Pseudomonas aeruginosa PAO1. Biomol NMR Assign 2017; 11:25-28. [PMID: 27714507 DOI: 10.1007/s12104-016-9714-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 10/01/2016] [Indexed: 06/06/2023]
Abstract
Pseudomonas aeruginosa is a highly adaptable opportunistic pathogen. It can infect vulnerable patients such as those with cystic fibrosis or hospitalized in intensive care units where it is responsible for both acute and chronic infection. The switch between these infections is controlled by a complex regulatory system involving the central GacS/GacA two-component system that activates the production of two small non-coding RNAs. GacS is a histidine kinase harboring one periplasmic detection domain, two inner-membrane helices and three H1/D1/H2 cytoplasmic domains. By detecting a yet unknown signal, the GacS histidine-kinase periplasmic detection domain (GacSp) is predicted to play a key role in activating the GacS/GacA pathway. Here, we present the chemical shift assignment of 96 % of backbone atoms (HN, N, C, Cα, Cβ and Hα), 88 % aliphatic hydrogen atoms and 90 % of aliphatic carbon atoms of this domain. The NMR-chemical shift data, on the basis of Talos server secondary structure predictions, reveal that GacSp consists of 3 β-strands, 3 α-helices and a major loop devoid of secondary structures.
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Affiliation(s)
| | - Olivier Bornet
- LISM, IMM, CNRS, Aix-Marseille Univ, 13402, Marseille, France
| | - Firas Fadel
- AFMB, CNRS, Aix Marseille Univ, Marseille, France
- LISM, IMM, CNRS, Aix-Marseille Univ, 13402, Marseille, France
| | - Yves Bourne
- AFMB, CNRS, Aix Marseille Univ, Marseille, France
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Ong LLS, Kundukad B, Dauwels J, Doyle P, Asada HH. Detecting cell division of Pseudomonas aeruginosa bacteria from bright-field microscopy images with hidden conditional random fields. Annu Int Conf IEEE Eng Med Biol Soc 2017; 2016:3985-3988. [PMID: 28269158 DOI: 10.1109/embc.2016.7591600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
An approach to automatically detect bacteria division with temporal models is presented. To understand how bacteria migrate and proliferate to form complex multicellular behaviours such as biofilms, it is desirable to track individual bacteria and detect cell division events. Unlike eukaryotic cells, prokaryotic cells such as bacteria lack distinctive features, causing bacteria division difficult to detect in a single image frame. Furthermore, bacteria may detach, migrate close to other bacteria and may orientate themselves at an angle to the horizontal plane. Our system trains a hidden conditional random field (HCRF) model from tracked and aligned bacteria division sequences. The HCRF model classifies a set of image frames as division or otherwise. The performance of our HCRF model is compared with a Hidden Markov Model (HMM). The results show that a HCRF classifier outperforms a HMM classifier. From 2D bright field microscopy data, it is a challenge to separate individual bacteria and associate observations to tracks. Automatic detection of sequences with bacteria division will improve tracking accuracy.
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Lee M, Hesek D, Dik DA, Fishovitz J, Lastochkin E, Boggess B, Fisher JF, Mobashery S. From Genome to Proteome to Elucidation of Reactions for All Eleven Known Lytic Transglycosylases from Pseudomonas aeruginosa. Angew Chem Int Ed Engl 2017; 56:2735-2739. [PMID: 28128504 DOI: 10.1002/anie.201611279] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 12/09/2016] [Indexed: 11/07/2022]
Abstract
An enzyme superfamily, the lytic transglycosylases (LTs), occupies the space between the two membranes of Gram-negative bacteria. LTs catalyze the non-hydrolytic cleavage of the bacterial peptidoglycan cell-wall polymer. This reaction is central to the growth of the cell wall, for excavating the cell wall for protein insertion, and for monitoring the cell wall so as to initiate resistance responses to cell-wall-acting antibiotics. The nefarious Gram-negative pathogen Pseudomonas aeruginosa encodes eleven LTs. With few exceptions, their substrates and functions are unknown. Each P. aeruginosa LT was expressed as a soluble protein and evaluated with a panel of substrates (both simple and complex mimetics of their natural substrates). Thirty-one distinct products distinguish these LTs with respect to substrate recognition, catalytic activity, and relative exolytic or endolytic ability. These properties are foundational to an understanding of the LTs as catalysts and as antibiotic targets.
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Affiliation(s)
- Mijoon Lee
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Dusan Hesek
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - David A Dik
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Jennifer Fishovitz
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Elena Lastochkin
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Bill Boggess
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Jed F Fisher
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Shahriar Mobashery
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
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Bodelón G, Montes-García V, López-Puente V, Hill EH, Hamon C, Sanz-Ortiz MN, Rodal-Cedeira S, Costas C, Celiksoy S, Pérez-Juste I, Scarabelli L, La Porta A, Pérez-Juste J, Pastoriza-Santos I, Liz-Marzán LM. Detection and imaging of quorum sensing in Pseudomonas aeruginosa biofilm communities by surface-enhanced resonance Raman scattering. Nat Mater 2016; 15:1203-1211. [PMID: 27500808 PMCID: PMC5082732 DOI: 10.1038/nmat4720] [Citation(s) in RCA: 178] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 07/04/2016] [Indexed: 05/15/2023]
Abstract
Most bacteria in nature exist as biofilms, which support intercellular signalling processes such as quorum sensing (QS), a cell-to-cell communication mechanism that allows bacteria to monitor and respond to cell density and changes in the environment. As QS and biofilms are involved in the ability of bacteria to cause disease, there is a need for the development of methods for the non-invasive analysis of QS in natural bacterial populations. Here, by using surface-enhanced resonance Raman scattering spectroscopy, we report rationally designed nanostructured plasmonic substrates for the in situ, label-free detection of a QS signalling metabolite in growing Pseudomonas aeruginosa biofilms and microcolonies. The in situ, non-invasive plasmonic imaging of QS in biofilms provides a powerful analytical approach for studying intercellular communication on the basis of secreted molecules as signals.
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Affiliation(s)
- Gustavo Bodelón
- Departamento de Química Física, Universidade de Vigo, 36310 Vigo, Spain
| | | | | | - Eric H Hill
- Bionanoplasmonics Laboratory, CIC biomaGUNE, Paseo de Miramón 182, 20009 Donostia-San Sebastián, Spain
| | - Cyrille Hamon
- Bionanoplasmonics Laboratory, CIC biomaGUNE, Paseo de Miramón 182, 20009 Donostia-San Sebastián, Spain
| | - Marta N Sanz-Ortiz
- Bionanoplasmonics Laboratory, CIC biomaGUNE, Paseo de Miramón 182, 20009 Donostia-San Sebastián, Spain
| | | | - Celina Costas
- Departamento de Química Física, Universidade de Vigo, 36310 Vigo, Spain
| | - Sirin Celiksoy
- Departamento de Química Física, Universidade de Vigo, 36310 Vigo, Spain
| | | | - Leonardo Scarabelli
- Bionanoplasmonics Laboratory, CIC biomaGUNE, Paseo de Miramón 182, 20009 Donostia-San Sebastián, Spain
| | - Andrea La Porta
- Bionanoplasmonics Laboratory, CIC biomaGUNE, Paseo de Miramón 182, 20009 Donostia-San Sebastián, Spain
| | - Jorge Pérez-Juste
- Departamento de Química Física, Universidade de Vigo, 36310 Vigo, Spain
| | | | - Luis M Liz-Marzán
- Departamento de Química Física, Universidade de Vigo, 36310 Vigo, Spain
- Bionanoplasmonics Laboratory, CIC biomaGUNE, Paseo de Miramón 182, 20009 Donostia-San Sebastián, Spain
- Ikerbasque, Basque Foundation for Science, 48013 Bilbao, Spain
- Biomedical Research Networking Center in Bioengineering, Biomaterials, and Nanomedicine (CIBER-BBN), 20009 Donostia - San Sebastián, Spain
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Abstract
BACKGROUND Microbial systems in which the extracellular environment varies both spatially and temporally are very common in nature and in engineering applications. While the use of genome-scale metabolic reconstructions for steady-state flux balance analysis (FBA) and extensions for dynamic FBA are common, the development of spatiotemporal metabolic models has received little attention. RESULTS We present a general methodology for spatiotemporal metabolic modeling based on combining genome-scale reconstructions with fundamental transport equations that govern the relevant convective and/or diffusional processes in time and spatially varying environments. Our solution procedure involves spatial discretization of the partial differential equation model followed by numerical integration of the resulting system of ordinary differential equations with embedded linear programs using DFBAlab, a MATLAB code that performs reliable and efficient dynamic FBA simulations. We demonstrate our methodology by solving spatiotemporal metabolic models for two systems of considerable practical interest: (1) a bubble column reactor with the syngas fermenting bacterium Clostridium ljungdahlii; and (2) a chronic wound biofilm with the human pathogen Pseudomonas aeruginosa. Despite the complexity of the discretized models which consist of 900 ODEs/600 LPs and 250 ODEs/250 LPs, respectively, we show that the proposed computational framework allows efficient and robust model solution. CONCLUSIONS Our study establishes a new paradigm for formulating and solving genome-scale metabolic models with both time and spatial variations and has wide applicability to natural and engineered microbial systems.
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Affiliation(s)
- Jin Chen
- Department of Chemical Engineering, University of Massachusetts, 240 Thatcher Way, Life Science Laboratories Building, Amherst, MA, 01003, USA.
| | - Jose A Gomez
- Department of Chemical Engineering, Process Systems Engineering Laboratory, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
| | - Kai Höffner
- Department of Chemical Engineering, Process Systems Engineering Laboratory, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
| | - Poonam Phalak
- Department of Chemical Engineering, University of Massachusetts, 240 Thatcher Way, Life Science Laboratories Building, Amherst, MA, 01003, USA.
| | - Paul I Barton
- Department of Chemical Engineering, Process Systems Engineering Laboratory, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
| | - Michael A Henson
- Department of Chemical Engineering, University of Massachusetts, 240 Thatcher Way, Life Science Laboratories Building, Amherst, MA, 01003, USA.
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Yu F, Yu X, Yu H, Hu M, Qu J, Zhu K, Wang M. [Effect of cis-vaccinate acid on swarming ability of Pseudomonas aeruginosa]. Wei Sheng Wu Xue Bao 2015; 55:1600-1607. [PMID: 27101703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
OBJECTIVE To study the effect of fatty acids composition on swarming mobility in Pseudomonas aeruginosa. METHODS We constructed a fabF-knockout mutant of PAO1 (YFF-1) by double exchange principle, overexpressed FabF in YFF-1 mutant to recover the mobility, and compared the swarming ability of wild type, YFF-1 mutant and mutant with plasmid pUCP18Gm-fabF. The change of fatty acids composition was analyzed using gas chromatography to explain the difference of swarming ability. RESULTS Swarming ability disappeared in YFF-1 mutant and was recovered in YFF-1 with plasmid pUCP18Gm-fabF. Gas chromatography analysis revealed that fatty acids composition changed in YFF-1. The cis-vaccinate acid (C18:1delta11) content decreased from 33.6% to 8.9%, and the ratio of unsaturated fatty acids to saturated fatty acids (UFA: SFA) was deduced from 0.96 to 0.74. The recovery of cis-vaccinate acid content was 20.9% and UFA:SFA 1.09 after expression of fabF. CONCLUSION Expression level of FabF played an important role in regulating swarming ability of PAO1. The decrease of cis-vaccinate acid content and unsaturation degree of fatty acids, especially the sharp decrease of cis-vaccinate acid, may be vital causes of swarming ability disappearance in YFF-1.
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Nguyen SH, Webb HK. Sensitive Detection of Deliquescent Bacterial Capsules through Nanomechanical Analysis. Langmuir 2015; 31:11311-11317. [PMID: 26425936 DOI: 10.1021/acs.langmuir.5b02546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Encapsulated bacteria usually exhibit strong resistance to a wide range of sterilization methods, and are often virulent. Early detection of encapsulation can be crucial in microbial pathology. This work demonstrates a fast and sensitive method for the detection of encapsulated bacterial cells. Nanoindentation force measurements were used to confirm the presence of deliquescent bacterial capsules surrounding bacterial cells. Force/distance approach curves contained characteristic linear-nonlinear-linear domains, indicating cocompression of the capsular layer and cell, indentation of the capsule, and compression of the cell alone. This is a sensitive method for the detection and verification of the encapsulation status of bacterial cells. Given that this method was successful in detecting the nanomechanical properties of two different layers of cell material, i.e. distinguishing between the capsule and the remainder of the cell, further development may potentially lead to the ability to analyze even thinner cellular layers, e.g. lipid bilayers.
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Affiliation(s)
- Song Ha Nguyen
- Faculty of Science, Engineering and Technology, Swinburne University of Technology , P.O. Box 218, Hawthorn 3122, Victoria, Australia
| | - Hayden K Webb
- Faculty of Science, Engineering and Technology, Swinburne University of Technology , P.O. Box 218, Hawthorn 3122, Victoria, Australia
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Costas C, López-Puente V, Bodelón G, González-Bello C, Pérez-Juste J, Pastoriza-Santos I, Liz-Marzán LM. Using surface enhanced Raman scattering to analyze the interactions of protein receptors with bacterial quorum sensing modulators. ACS Nano 2015; 9:5567-76. [PMID: 25927541 PMCID: PMC4446724 DOI: 10.1021/acsnano.5b01800] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Many members of the LuxR family of quorum sensing (QS) transcriptional activators, including LasR of Pseudomonas aeruginosa, are believed to require appropriate acyl-homoserine lactone (acyl-HSL) ligands to fold into an active conformation. The failure to purify ligand-free LuxR homologues in nonaggregated form at the high concentrations required for their structural characterization has limited the understanding of the mechanisms by which QS receptors are activated. Surface-enhanced Raman scattering (SERS) is a vibrational spectroscopy technique that can be applied to study proteins at extremely low concentrations in their active state. The high sensitivity of SERS has allowed us to detect molecular interactions between the ligand-binding domain of LasR (LasRLBD) as a soluble apoprotein and modulators of P. aeruginosa QS. We found that QS activators and inhibitors produce differential SERS fingerprints in LasRLBD, and in combination with molecular docking analysis provide insight into the relevant interaction mechanism. This study reveals signal-specific structural changes in LasR upon ligand binding, thereby confirming the applicability of SERS to analyze ligand-induced conformational changes in proteins.
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Affiliation(s)
- Celina Costas
- Departamento de Química Física, Universidade de Vigo, 36301 Vigo, Spain
| | | | - Gustavo Bodelón
- Departamento de Química Física, Universidade de Vigo, 36301 Vigo, Spain
- Address correspondence to ,
| | - Concepción González-Bello
- Centro Singular de Investigación en Química Biológica y Materiales Moleculares (CIQUS), Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - Jorge Pérez-Juste
- Departamento de Química Física, Universidade de Vigo, 36301 Vigo, Spain
| | | | - Luis M. Liz-Marzán
- Departamento de Química Física, Universidade de Vigo, 36301 Vigo, Spain
- Bionanoplasmonics Laboratory, CIC biomaGUNE, Paseo de Miramón 182, 20009 Donostia-San Sebastian, Spain
- Ikerbasque, Basque Foundation for Science, 48013 Bilbao, Spain
- Address correspondence to ,
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Wu DQ, Huang WF, Duan QJ, Cheng HJ, Wang CZ. [Sodium houttuyfonate inhibits virulence related motility of Pseudomonas aeruginosa]. Zhongguo Zhong Yao Za Zhi 2015; 40:1585-1588. [PMID: 26281603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Sodium houttuyfonate (SH) is a derivative of effective component of a Chinese material medica, Houttuynia cordata, which is applied in anti-infection of microorganism. But, the antimicrobial mechanisms of SH still remain unclear. Here, we firstly discovered that SH effectively inhibits the three types of virulence related motility of.Pseudomonas aeruginosa, i.e., swimming, twitching and swarming. The plate assay results showed that the inhibitory action of SH against swimming and twitching in 24 h and swarming in 48 h is dose-dependent; and bacteria nearly lost all of the motile activities under the concentration of 1 x minimum inhibitory concentration (MIC) (512 mg x L(-1) same as azithromycin positive group (1 x MIC, 16 mg x L(-1)). Furthermore, we found that the expression of structural gene flgB and pilG is down-regulated by SH, which implies that inhibitory mechanism of SH against motility of P. aeruginosa may be due to the inhibition of flagella and pili bioformation of P. aeruginosa by SR Therefore, our presented results firstly demonstrate that SH effectively inhibits the motility activities of P. aeruginosa, and suggest that SH could be a promising antipseudomonas agents in clinic.
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38
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Nosková L, Kubíčková B, Vašková L, Bláhová B, Wimmerová M, Stiborová M, Hodek P. Fluorescent cellular assay for screening agents inhibiting Pseudomonas aeruginosa adherence. Sensors (Basel) 2015; 15:1945-53. [PMID: 25602268 PMCID: PMC4327110 DOI: 10.3390/s150101945] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 01/09/2015] [Indexed: 11/16/2022]
Abstract
Antibodies against Pseudomonas aeruginosa (PA) lectin, PAIIL, which is a virulence factor mediating the bacteria binding to epithelium cells, were prepared in chickens and purified from egg yolks. To examine these antibodies as a prophylactic agent preventing the adhesion of PA we developed a well plate assay based on fluorescently labeled bacteria and immortalized epithelium cell lines derived from normal and cystic fibrosis (CF) human lungs. The antibodies significantly inhibited bacteria adhesion (up to 50%) in both cell lines. In agreement with in vivo data, our plate assay showed higher susceptibility of CF cells towards the PA adhesion as compared to normal epithelium. This finding proved the reliability of the developed experimental system.
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Affiliation(s)
- Libuše Nosková
- Department of Biochemistry, Faculty of Science, Charles University in Prague, Hlavova 8, 128 40 Prague 2, Czech Republic.
| | - Božena Kubíčková
- Department of Biochemistry, Faculty of Science, Charles University in Prague, Hlavova 8, 128 40 Prague 2, Czech Republic.
| | - Lucie Vašková
- Department of Biochemistry, Faculty of Science, Charles University in Prague, Hlavova 8, 128 40 Prague 2, Czech Republic.
| | - Barbora Bláhová
- Department of Biochemistry, Faculty of Science, Charles University in Prague, Hlavova 8, 128 40 Prague 2, Czech Republic.
| | - Michaela Wimmerová
- Central European Institute of Technology, Masaryk University, Kamenice 753/5, 625 00 Brno, Czech Republic.
| | - Marie Stiborová
- Department of Biochemistry, Faculty of Science, Charles University in Prague, Hlavova 8, 128 40 Prague 2, Czech Republic.
| | - Petr Hodek
- Department of Biochemistry, Faculty of Science, Charles University in Prague, Hlavova 8, 128 40 Prague 2, Czech Republic.
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Huang CJ, Wang LC, Shyue JJ, Chang YC. Developing antifouling biointerfaces based on bioinspired zwitterionic dopamine through pH-modulated assembly. Langmuir 2014; 30:12638-12646. [PMID: 25283175 DOI: 10.1021/la503191b] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The use of synthetic biomaterials as implantable devices typically is accompanied by considerable nonspecific adsorption of proteins, cells, and bacteria. These may eventually induce adverse pathogenic problems in clinical practice, such as thrombosis and biomaterial-associated infection. Thus, an effective surface coating for medical devices has been pursued to repel nonspecific adsorption from surfaces. In this study, we employ an adhesive dopamine molecule conjugated with zwitterionic sulfobetaine moiety (SB-DA), developed based on natural mussels, as a surface ligand for the modification of TiO2. The electrochemical study shows that the SB-DA exhibits fully reversible reduction-oxidation behavior at pH 3, but it is irreversible at pH 8. A contact angle goniometer and X-ray photoelectron spectroscopy were utilized to explore the surface hydration, chemical states, and bonding mechanism of SB-DA. The results indicate that the binding between hydroxyl groups of SB-DA and TiO2 converts from hydrogen bonds to bidentate binding upon the pH transition from pH 3 to 8. In order to examine the antifouling properties of SB-DA thin films, the modified substrates were brought into contact with bovine serum albumin and bacteria solutions. The fouling levels were monitored using a quartz crystal microbalance with dissipation sensor and fluorescence optical microscope. Tests showed that the sample prepared via the pH transition approach provides the best resistance to nonspecific adsorption due to the high coverage and stability of the SB-DA films. These findings support the mechanism of the pH-modulated assembly of SB-DA molecules, and for the first time we demonstrate the antifouling properties of the SB-DA to be comparable with traditional thiol-based zwitterionic self-assemblies. The success of modification with SB-DA opens an avenue for developing a biologically inspired surface chemistry and can have applications over a wide spectrum of bioapplications. The strategy of the pH transition can also be applied to other functional dopamine derivatives.
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Affiliation(s)
- Chun-Jen Huang
- Graduate Institute of Biomedical Engineering and ‡Chemical & Materials Engineering Department, National Central University , Jhong-Li, Taoyuan 320, Taiwan
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Das T, Sehar S, Koop L, Wong YK, Ahmed S, Siddiqui KS, Manefield M. Influence of calcium in extracellular DNA mediated bacterial aggregation and biofilm formation. PLoS One 2014; 9:e91935. [PMID: 24651318 PMCID: PMC3961253 DOI: 10.1371/journal.pone.0091935] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 02/18/2014] [Indexed: 12/03/2022] Open
Abstract
Calcium (Ca2+) has an important structural role in guaranteeing the integrity of the outer lipopolysaccharide layer and cell walls of bacterial cells. Extracellular DNA (eDNA) being part of the slimy matrix produced by bacteria promotes biofilm formation through enhanced structural integrity of the matrix. Here, the concurrent role of Ca2+ and eDNA in mediating bacterial aggregation and biofilm formation was studied for the first time using a variety of bacterial strains and the thermodynamics of DNA to Ca2+ binding. It was found that the eDNA concentrations under both planktonic and biofilm growth conditions were different among bacterial strains. Whilst Ca2+ had no influence on eDNA release, presence of eDNA by itself favours bacterial aggregation via attractive acid-base interactions in addition, its binding with Ca2+ at biologically relevant concentrations was shown further increase in bacterial aggregation via cationic bridging. Negative Gibbs free energy (ΔG) values in iTC data confirmed that the interaction between DNA and Ca2+ is thermodynamically favourable and that the binding process is spontaneous and exothermic owing to its highly negative enthalpy. Removal of eDNA through DNase I treatment revealed that Ca2+ alone did not enhance cell aggregation and biofilm formation. This discovery signifies the importance of eDNA and concludes that existence of eDNA on bacterial cell surfaces is a key facilitator in binding of Ca2+ to eDNA thereby mediating bacterial aggregation and biofilm formation.
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Affiliation(s)
- Theerthankar Das
- Centre for Marine BioInnovation, School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, Australia
- * E-mail:
| | - Shama Sehar
- Centre for Marine BioInnovation, School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, Australia
- Department of Microbiology, Quaid-i-Azam University, Islamabad, Pakistan
| | - Leena Koop
- Centre for Marine BioInnovation, School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, Australia
| | - Yie Kuan Wong
- Centre for Marine BioInnovation, School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, Australia
| | - Safia Ahmed
- Department of Microbiology, Quaid-i-Azam University, Islamabad, Pakistan
| | - Khawar Sohail Siddiqui
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, Australia
| | - Mike Manefield
- Centre for Marine BioInnovation, School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, Australia
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Vater SM, Weiße S, Maleschlijski S, Lotz C, Koschitzki F, Schwartz T, Obst U, Rosenhahn A. Swimming behavior of Pseudomonas aeruginosa studied by holographic 3D tracking. PLoS One 2014; 9:e87765. [PMID: 24498187 PMCID: PMC3909247 DOI: 10.1371/journal.pone.0087765] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 12/30/2013] [Indexed: 11/25/2022] Open
Abstract
Holographic 3D tracking was applied to record and analyze the swimming behavior of Pseudomonas aeruginosa. The obtained trajectories allow to qualitatively and quantitatively analyze the free swimming behavior of the bacterium. This can be classified into five distinct swimming patterns. In addition to the previously reported smooth and oscillatory swimming motions, three additional patterns are distinguished. We show that Pseudomonas aeruginosa performs helical movements which were so far only described for larger microorganisms. Occurrence of the swimming patterns was determined and transitions between the patterns were analyzed.
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Affiliation(s)
- Svenja M. Vater
- Applied Physical Chemistry, Ruprecht-Karls-University Heidelberg, Germany
- Institute for Functional Interfaces, IFG, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Sebastian Weiße
- Applied Physical Chemistry, Ruprecht-Karls-University Heidelberg, Germany
- Institute for Functional Interfaces, IFG, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Stojan Maleschlijski
- Applied Physical Chemistry, Ruprecht-Karls-University Heidelberg, Germany
- Institute for Functional Interfaces, IFG, Karlsruhe Institute of Technology, Karlsruhe, Germany
- Analytical Chemistry-Biointerfaces, Ruhr-University Bochum, Germany
| | - Carmen Lotz
- Institute for Functional Interfaces, IFG, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Florian Koschitzki
- Applied Physical Chemistry, Ruprecht-Karls-University Heidelberg, Germany
| | - Thomas Schwartz
- Institute for Functional Interfaces, IFG, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Ursula Obst
- Institute for Functional Interfaces, IFG, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Axel Rosenhahn
- Institute for Functional Interfaces, IFG, Karlsruhe Institute of Technology, Karlsruhe, Germany
- Analytical Chemistry-Biointerfaces, Ruhr-University Bochum, Germany
- * E-mail:
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Abstract
In this chapter methods for growing and analyzing biofilms under hydrodynamic conditions in flow cells are described. Use of flow cells allows for direct microscopic investigation of biofilm formation. The flow in these chambers is essentially laminar, which means that the biofilms can be grown under highly controlled conditions, and that perturbations such as addition of antibiotics or change of the growth medium can be done efficiently at a defined time point. The protocol includes construction of the flow cell and the bubble trap, assembly and sterilization of the flow cell system, inoculation of the flow cells, running of the system, confocal laser scanning microscopy and image analysis, and disassembly and cleaning of the system.
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Affiliation(s)
- Tim Tolker-Nielsen
- Department of International Health, Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen N, Denmark,
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43
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Abstract
Proteins within a cell are localized into specific cellular compartments, allowing compartmentalization of distinct tasks. If we consider lipid bilayers as compartments, then gram-negative bacteria such as Pseudomonas aeruginosa can target proteins to five distinct locations: the cytoplasm, the inner membrane, the periplasm, the outer membrane, and the extracellular environment. In this chapter, we describe how the different compartments can be selectively isolated by a combination of centrifugation and disruption techniques. Fractionation of the cells into subcellular compartments enables protein enrichment and is essential to accurately determine the localization of specific proteins, which is the first step towards understanding the function of a protein in the cell.
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Affiliation(s)
- Bérengère Ize
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, UMR7255 - CNRS - Aix Marseille Université, IMM 31, Ch. J. Aiguier, 13402, Marseille, CEDEX 20, France,
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Beury-Cirou A, Tannières M, Minard C, Soulère L, Rasamiravaka T, Dodd RH, Queneau Y, Dessaux Y, Guillou C, Vandeputte OM, Faure D. At a supra-physiological concentration, human sexual hormones act as quorum-sensing inhibitors. PLoS One 2013; 8:e83564. [PMID: 24376718 PMCID: PMC3871529 DOI: 10.1371/journal.pone.0083564] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Accepted: 11/13/2013] [Indexed: 01/06/2023] Open
Abstract
N-Acylhomoserine lactone (AHL)-mediated quorum-sensing (QS) regulates virulence functions in plant and animal pathogens such as Agrobacterium tumefaciens and Pseudomonas aeruginosa. A chemolibrary of more than 3500 compounds was screened using two bacterial AHL-biosensors to identify QS-inhibitors (QSIs). The purity and structure of 15 QSIs selected through this screening were verified using HPLC MS/MS tools and their activity tested on the A. tumefaciens and P. aeruginosa bacterial models. The IC50 value of the identified QSIs ranged from 2.5 to 90 µg/ml, values that are in the same range as those reported for the previously identified QSI 4-nitropyridine-N-oxide (IC50 24 µg/ml). Under the tested culture conditions, most of the identified QSIs did not exhibit bacteriostatic or bactericidal activities. One third of the tested QSIs, including the plant compound hordenine and the human sexual hormone estrone, decreased the frequency of the QS-regulated horizontal transfer of the tumor-inducing (Ti) plasmid in A. tumefaciens. Hordenine, estrone as well as its structural relatives estriol and estradiol, also decreased AHL accumulation and the expression of six QS-regulated genes (lasI, lasR, lasB, rhlI, rhlR, and rhlA) in cultures of the opportunist pathogen P. aeruginosa. Moreover, the ectopic expression of the AHL-receptors RhlR and LasR of P. aeruginosa in E. coli showed that their gene-regulatory activity was affected by the QSIs. Finally, modeling of the structural interactions between the human hormones and AHL-receptors LasR of P. aeruginosa and TraR of A. tumefaciens confirmed the competitive binding capability of the human sexual hormones. This work indicates potential interferences between bacterial and eukaryotic hormonal communications.
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Affiliation(s)
- Amélie Beury-Cirou
- Institut des Sciences du Végétal (ISV) UPR 2355, Centre National de la Recherche Scientifique, Gif-sur-Yvette, France
- Seeds Innovation Protection Research and Environment (SIPRE), Comité Nord Plants de Pommes de Terre (CNPPT), Achicourt, France
| | - Mélanie Tannières
- Institut des Sciences du Végétal (ISV) UPR 2355, Centre National de la Recherche Scientifique, Gif-sur-Yvette, France
| | - Corinne Minard
- Institut de Chimie des Substances Naturelles (ICSN) UPR2301, Centre National de la Recherche Scientifique, Gif-sur-Yvette, France
| | - Laurent Soulère
- Institut de Chimie et Biochimie Moléculaires et Supramoléculaires (ICBMS) UMR 5246, INSA Lyon-Université Lyon 1, Villeurbanne, France
| | - Tsiry Rasamiravaka
- Laboratoire de Biotechnologie Végétale, Université Libre de Bruxelles, Gosselies, Belgium
| | - Robert H. Dodd
- Institut de Chimie des Substances Naturelles (ICSN) UPR2301, Centre National de la Recherche Scientifique, Gif-sur-Yvette, France
| | - Yves Queneau
- Institut de Chimie et Biochimie Moléculaires et Supramoléculaires (ICBMS) UMR 5246, INSA Lyon-Université Lyon 1, Villeurbanne, France
| | - Yves Dessaux
- Institut des Sciences du Végétal (ISV) UPR 2355, Centre National de la Recherche Scientifique, Gif-sur-Yvette, France
| | - Catherine Guillou
- Institut de Chimie des Substances Naturelles (ICSN) UPR2301, Centre National de la Recherche Scientifique, Gif-sur-Yvette, France
| | - Olivier M. Vandeputte
- Laboratoire de Biotechnologie Végétale, Université Libre de Bruxelles, Gosselies, Belgium
- * E-mail: (OV); (DF)
| | - Denis Faure
- Institut des Sciences du Végétal (ISV) UPR 2355, Centre National de la Recherche Scientifique, Gif-sur-Yvette, France
- * E-mail: (OV); (DF)
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Zhang T, Pabst B, Klapper I, Stewart PS. General theory for integrated analysis of growth, gene, and protein expression in biofilms. PLoS One 2013; 8:e83626. [PMID: 24376726 PMCID: PMC3871705 DOI: 10.1371/journal.pone.0083626] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 11/06/2013] [Indexed: 01/23/2023] Open
Abstract
A theory for analysis and prediction of spatial and temporal patterns of gene and protein expression within microbial biofilms is derived. The theory integrates phenomena of solute reaction and diffusion, microbial growth, mRNA or protein synthesis, biomass advection, and gene transcript or protein turnover. Case studies illustrate the capacity of the theory to simulate heterogeneous spatial patterns and predict microbial activities in biofilms that are qualitatively different from those of planktonic cells. Specific scenarios analyzed include an inducible GFP or fluorescent protein reporter, a denitrification gene repressed by oxygen, an acid stress response gene, and a quorum sensing circuit. It is shown that the patterns of activity revealed by inducible stable fluorescent proteins or reporter unstable proteins overestimate the region of activity. This is due to advective spreading and finite protein turnover rates. In the cases of a gene induced by either limitation for a metabolic substrate or accumulation of a metabolic product, maximal expression is predicted in an internal stratum of the biofilm. A quorum sensing system that includes an oxygen-responsive negative regulator exhibits behavior that is distinct from any stage of a batch planktonic culture. Though here the analyses have been limited to simultaneous interactions of up to two substrates and two genes, the framework applies to arbitrarily large networks of genes and metabolites. Extension of reaction-diffusion modeling in biofilms to the analysis of individual genes and gene networks is an important advance that dovetails with the growing toolkit of molecular and genetic experimental techniques.
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Affiliation(s)
- Tianyu Zhang
- Department of Mathematical Sciences, Montana State University, Bozeman, Montana, United States of America
| | - Breana Pabst
- Department of Chemical and Biological Engineering, Montana State University, Bozeman, Montana, United States of America
| | - Isaac Klapper
- Department of Mathematics, Temple University, Philadelphia, Pennsylvania, United States of America
| | - Philip S. Stewart
- Department of Chemical and Biological Engineering, Montana State University, Bozeman, Montana, United States of America
- Center for Biofilm Engineering, Montana State University, Bozeman, Montana, United States of America
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Blus-Kadosh I, Zilka A, Yerushalmi G, Banin E. The effect of pstS and phoB on quorum sensing and swarming motility in Pseudomonas aeruginosa. PLoS One 2013; 8:e74444. [PMID: 24023943 PMCID: PMC3762822 DOI: 10.1371/journal.pone.0074444] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Accepted: 08/02/2013] [Indexed: 12/04/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that can cause a wide range of infections and inflammations in a variety of hosts, such as chronic biofilm associated lung infections in Cystic Fibrosis patients. Phosphate, an essential nutrient, has been recognized as an important signal that affects virulence in P. aeruginosa. In the current study we examined the connection between phosphate regulation and surface motility in P. aeruginosa. We focused on two important genes, pstS, which is involved in phosphate uptake, and phoB, a central regulator that responds to phosphate starvation. We found that a mutant lacking pstS is constantly starved for phosphate and has a hyper swarming phenotype. Phosphate starvation also induced swarming in the wild type. The phoB mutant, on the other hand, did not express phosphate starvation even when phosphate was limited and showed no swarming. A double mutant lacking both genes (pstS and phoB) showed a similar phenotype to the phoB mutant (i.e. no swarming). This highlights the role of phoB in controlling swarming motility under phosphate-depleted conditions. Finally, we were able to demonstrate that PhoB controls swarming by up-regulating the Rhl quorum sensing system in P. aeruginosa, which resulted in hyper production of rhamonlipids: biosurfactants that are known to induce swarming motility.
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Affiliation(s)
- Inna Blus-Kadosh
- The Institute for Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan, Israel
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, Israel
| | - Anat Zilka
- The Institute for Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan, Israel
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, Israel
| | - Gal Yerushalmi
- The Institute for Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan, Israel
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, Israel
| | - Ehud Banin
- The Institute for Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan, Israel
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, Israel
- * E-mail:
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Kwon KS, Kim SB, Choi NC, Kim DJ, Lee S, Lee SH, Choi JW. Deposition and transport of Pseudomonas aeruginosa in porous media: lab-scale experiments and model analysis. Environ Technol 2013; 34:2757-2764. [PMID: 24527639 DOI: 10.1080/09593330.2013.788070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
In this study, the deposition and transport of Pseudomonas aeruginosa on sandy porous materials have been investigated under static and dynamic flow conditions. For the static experiments, both equilibrium and kinetic batch tests were performed at a 1:3 and 3:1 soil:solution ratio. The batch data were analysed to quantify the deposition parameters under static conditions. Column tests were performed for dynamic flow experiments with KCl solution and bacteria suspended in (1) deionized water, (2) mineral salt medium (MSM) and (3) surfactant + MSM. The equilibrium distribution coefficient (K(d)) was larger at a 1:3 (2.43 mL g(-1)) than that at a 3:1 (0.28 mL g(-1)) soil:solution ratio. Kinetic batch experiments showed that the reversible deposition rate coefficient (k(att)) and the release rate coefficient (k(det)) at a soil:solution ratio of 3:1 were larger than those at a 1:3 ratio. Column experiments showed that an increase in ionic strength resulted in a decrease in peak concentration of bacteria, mass recovery and tailing of the bacterial breakthrough curve (BTC) and that the presence of surfactant enhanced the movement of bacteria through quartz sand, giving increased mass recovery and tailing. Deposition parameters under dynamic condition were determined by fitting BTCs to four different transport models, (1) kinetic reversible, (2) two-site, (3) kinetic irreversible and (4) kinetic reversible and irreversible models. Among these models, Model 4 was more suitable than the others since it includes the irreversible sorption term directly related to the mass loss of bacteria observed in the column experiment. Applicability of the parameters obtained from the batch experiments to simulate the column breakthrough data is evaluated.
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Affiliation(s)
- Kyu-Sang Kwon
- Center for Water Resource Cycle Research, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791, Republic of Korea
| | - Song-Bae Kim
- Environmental Biocolloid Engineering Laboratory, Program in Rural System Engineering, Seoul National University, Seoul 151-742, Republic of Korea
| | - Nag-Choul Choi
- Environmental Biocolloid Engineering Laboratory, Program in Rural System Engineering, Seoul National University, Seoul 151-742, Republic of Korea
| | - Dong-Ju Kim
- Department of Earth and Environmental Sciences, Korea University, Seoul 136-701, Republic of Korea
| | - Soonjae Lee
- Department of Earth and Environmental Sciences, Korea University, Seoul 136-701, Republic of Korea
| | - Sang-Hyup Lee
- Department of Earth and Environmental Sciences, Korea University, Seoul 136-701, Republic of Korea
| | - Jae-Woo Choi
- Center for Water Resource Cycle Research, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791, Republic of Korea
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Naves AF, Palombo RR, Carrasco LDM, Carmona-Ribeiro AM. Antimicrobial particles from emulsion polymerization of methyl methacrylate in the presence of quaternary ammonium surfactants. Langmuir 2013; 29:9677-9684. [PMID: 23841487 DOI: 10.1021/la401527j] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The purpose of this Article is to characterize polymeric particles of poly(methylmethacrylate) (PMMA) synthesized in the presence of one of two different quaternary ammonium surfactants (QACs): cetyltrimethylammonium bromide (CTAB) or dioctadecyldimethylammonium bromide (DODAB). The methods used are dynamic light scattering for sizing, polydispersity and zeta potential analysis, scanning electron microscopy (SEM) for morphology visualization, and plating plus colony-forming unities (CFU) counting for the determination of antimicrobial activity. The results point out the high QAC concentration required to obtain cationic and bioactive antimicrobial particles with good colloidal stability and a permanent load of the polymeric network with QACs. Over a range of micromolar QAC concentrations, there is remarkable antimicrobial activity of PMMA/CTAB or PMMA/DODAB particles, which is much higher than those determined for the QACs by themselves. Loading the biocompatible polyacrylate particles with QACs is a facile, fast, low-cost approach to obtaining highly efficient antimicrobial nanoparticles.
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Affiliation(s)
- Alliny F Naves
- Biocolloids Laboratory, Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, Caixa Postal 26077, CEP 05513-970, São Paulo SP, Brazil
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Zhang W, McLamore ES, Garland NT, Leon JVC, Banks MK. A simple method for quantifying biomass cell and polymer distribution in biofilms. J Microbiol Methods 2013; 94:367-74. [PMID: 23916866 DOI: 10.1016/j.mimet.2013.07.022] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Revised: 07/23/2013] [Accepted: 07/24/2013] [Indexed: 11/19/2022]
Abstract
Biofilms are ubiquitous and play an essential role in both environmental processes and hospital infections. Standard methods are not capable of quantifying biomass concentration in dilute suspensions. Furthermore, standard techniques cannot differentiate biomass composition. In this study, a user-friendly technique was developed for measuring biomass cell and polymer content in detached biofilms using a standard coulter counter. The method was demonstrated for an environmentally relevant strain of Pseudomonas aeruginosa (Schroeter) Migula grown in a bioreactor and also for a medically relevant strain of P. aeruginosa (PAO1) grown on standard growth pegs. Results were compared and validated by standard assays, including EPA method 1684 for measuring biomass, microscopic direct counts, and a crystal violet staining assay. The minimum detection limit for the coulter counter method (0.07 mg-biomass L(-1)) was significantly lower than the EPA method 1684 (1.9 ± 0.4 mg/L) and the crystal violet assay (1.1 ± 0.2 mg L(-1)). However, the coulter counter method is limited to dilute biomass samples (below 204 ± 16 mg L(-1)) due to clogging of the aperture tube. While biomass measurements are useful, the major advantage of the coulter counter method is the ability to directly determine EPS, cell, and aggregate fractions after mild chemical treatment. The rapid technique (4-5 min per sample) was used to measure biomass fractions in dispersed P. aeruginosa (Schroeter) and PAO1 biofilms. This technique will be critical for understanding biofilm formation/dispersal.
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Affiliation(s)
- Wen Zhang
- Department of Civil Engineering, University of Arkansas, 4190 Bell Engineering Center, Fayetteville, AR 72701, USA.
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Gensberger ET, Sessitsch A, Kostić T. Propidium monoazide-quantitative polymerase chain reaction for viable Escherichia coli and Pseudomonas aeruginosa detection from abundant background microflora. Anal Biochem 2013; 441:69-72. [PMID: 23756735 DOI: 10.1016/j.ab.2013.05.033] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2013] [Revised: 05/28/2013] [Accepted: 05/31/2013] [Indexed: 11/19/2022]
Abstract
Nucleic acid-based techniques represent a promising alternative to cultivation-based microbial water quality assessment methods. However, their application is hampered by their innate inability to differentiate between living and dead organisms. Propidium monoazide (PMA) treatment was proposed as an efficient approach for alleviating this limitation. In this study, we demonstrate the performance of PMA-quantitative polymerase chain reaction (qPCR) for the detection of indicator organisms (Escherichia coli and Pseudomonas aeruginosa) in a background of a highly abundant and complex microflora. Treatment with 10 μM PMA resulted in the complete or significant reduction of the false positive signal arising from the amplification of DNA from dead cells.
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