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Drożdżyński P, Rutkowska N, Rodziewicz M, Marchut-Mikołajczyk O. Bioactive Compounds Produced by Endophytic Bacteria and Their Plant Hosts-An Insight into the World of Chosen Herbaceous Ruderal Plants in Central Europe. Molecules 2024; 29:4456. [PMID: 39339451 PMCID: PMC11433698 DOI: 10.3390/molecules29184456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2024] [Revised: 09/09/2024] [Accepted: 09/17/2024] [Indexed: 09/30/2024] Open
Abstract
The natural environment has been significantly impacted by human activity, urbanization, and industrialization, leading to changes in living organisms and their adaptation to harsh conditions. Species, including plants, adapt to these changes by creating mechanisms and modifications that allow them to survive in harsh environments. Also, endophytes, microorganisms that live inside plants, can support plant growth and defense mechanisms in these conditions by synthesizing antimicrobial secondary metabolites. What is more, endophytes produce bioactive metabolites, including alkaloids, amines, and peptides, which play a crucial role in the relationship between endophytes and their host organisms. Endophytes themselves benefit from this by creating a stable environment for their survival and development. The aim of this review is to gain insight into endophytic bioactive metabolites from chosen synanthropic ruderal plants. Industrial activities release pollutants like heavy metals, by-products, and waste, which challenge living organisms and require adaptation. Synanthropic plants, where endophytes are abundant, are particularly valuable for their bioactive compounds, which are used in agriculture and medicine. This review presents, among others, endophytes of herbaceous ruderal plants from central Europe-Chelidonium majus L., Urtica dioica L., Plantago lanceolata L., Matricaria chamomilla L., Equisetum arvense L., Oenothera biennis L., Silybum marianum L., and Mentha piperita L.
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Affiliation(s)
- Piotr Drożdżyński
- Institute of Molecular and Industrial Biotechnology, Faculty of Biotechnology and Food Sciences, Lodz University of Technology, Stefanowskiego 2/22, 90-537 Lodz, Poland; (N.R.); (M.R.); (O.M.-M.)
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Rajewska M, Maciąg T, Narajczyk M, Jafra S. Carbon Source and Substrate Surface Affect Biofilm Formation by the Plant-Associated Bacterium Pseudomonas donghuensis P482. Int J Mol Sci 2024; 25:8351. [PMID: 39125921 PMCID: PMC11312691 DOI: 10.3390/ijms25158351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2024] [Revised: 07/25/2024] [Accepted: 07/26/2024] [Indexed: 08/12/2024] Open
Abstract
The ability of bacteria to colonize diverse environmental niches is often linked to their competence in biofilm formation. It depends on the individual characteristics of a strain, the nature of the colonized surface (abiotic or biotic), or the availability of certain nutrients. Pseudomonas donghuensis P482 efficiently colonizes the rhizosphere of various plant hosts, but a connection between plant tissue colonization and the biofilm formation ability of this strain has not yet been established. We demonstrate here that the potential of P482 to form biofilms on abiotic surfaces and the structural characteristics of the biofilm are influenced by the carbon source available to the bacterium, with glycerol promoting the process. Also, the type of substratum, polystyrene or glass, impacts the ability of P482 to attach to the surface. Moreover, P482 mutants in genes associated with motility or chemotaxis, the synthesis of polysaccharides, and encoding proteases or regulatory factors, which affect biofilm formation on glass, were fully capable of colonizing the root tissue of both tomato and maize hosts. Investigating the role of cellular factors in biofilm formation using these plant-associated bacteria shows that the ability of bacteria to form biofilm on abiotic surfaces does not necessarily mirror its ability to colonize plant tissues. Our research provides a broader perspective on the adaptation of these bacteria to various environments.
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Affiliation(s)
- Magdalena Rajewska
- Laboratory of Plant Microbiology, Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk, Abrahama 58, 80-307 Gdansk, Poland;
| | - Tomasz Maciąg
- Institute of Biology, Department of Botany, Warsaw University of Life Sciences, Nowoursynowska 159, 02-776 Warsaw, Poland;
| | - Magdalena Narajczyk
- Laboratory of Electron Microscopy, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland;
| | - Sylwia Jafra
- Laboratory of Plant Microbiology, Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk, Abrahama 58, 80-307 Gdansk, Poland;
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Arnault G, Marais C, Préveaux A, Briand M, Poisson AS, Sarniguet A, Barret M, Simonin M. Seedling microbiota engineering using bacterial synthetic community inoculation on seeds. FEMS Microbiol Ecol 2024; 100:fiae027. [PMID: 38503562 PMCID: PMC10977042 DOI: 10.1093/femsec/fiae027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 01/29/2024] [Accepted: 03/18/2024] [Indexed: 03/21/2024] Open
Abstract
Synthetic Communities (SynComs) are being developed and tested to manipulate plant microbiota and improve plant health. To date, only few studies proposed the use of SynCom on seed despite its potential for plant microbiota engineering. We developed and presented a simple and effective seedling microbiota engineering method using SynCom inoculation on seeds. The method was successful using a wide diversity of SynCom compositions and bacterial strains that are representative of the common bean seed microbiota. First, this method enables the modulation of seed microbiota composition and community size. Then, SynComs strongly outcompeted native seed and potting soil microbiota and contributed on average to 80% of the seedling microbiota. We showed that strain abundance on seed was a main driver of an effective seedling microbiota colonization. Also, selection was partly involved in seed and seedling colonization capacities since strains affiliated to Enterobacteriaceae and Erwiniaceae were good colonizers while Bacillaceae and Microbacteriaceae were poor colonizers. Additionally, the engineered seed microbiota modified the recruitment and assembly of seedling and rhizosphere microbiota through priority effects. This study shows that SynCom inoculation on seeds represents a promising approach to study plant microbiota assembly and its consequence on plant fitness.
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Affiliation(s)
- Gontran Arnault
- IRHS-UMR1345, Université d’Angers, INRAE, Institut Agro, SFR 4207 QuaSaV, 49071, Beaucouzé, France
| | - Coralie Marais
- IRHS-UMR1345, Université d’Angers, INRAE, Institut Agro, SFR 4207 QuaSaV, 49071, Beaucouzé, France
| | - Anne Préveaux
- IRHS-UMR1345, Université d’Angers, INRAE, Institut Agro, SFR 4207 QuaSaV, 49071, Beaucouzé, France
| | - Martial Briand
- IRHS-UMR1345, Université d’Angers, INRAE, Institut Agro, SFR 4207 QuaSaV, 49071, Beaucouzé, France
| | - Anne-Sophie Poisson
- Groupe d’Étude et de Contrôle des Variétés et des Semences (GEVES), 49070, Beaucouzé, France
| | - Alain Sarniguet
- IRHS-UMR1345, Université d’Angers, INRAE, Institut Agro, SFR 4207 QuaSaV, 49071, Beaucouzé, France
| | - Matthieu Barret
- IRHS-UMR1345, Université d’Angers, INRAE, Institut Agro, SFR 4207 QuaSaV, 49071, Beaucouzé, France
| | - Marie Simonin
- IRHS-UMR1345, Université d’Angers, INRAE, Institut Agro, SFR 4207 QuaSaV, 49071, Beaucouzé, France
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Yang L, Wang L, Wang M, Bajinka O, Wu G, Qin L, Tan Y. Oligoribonuclease mediates high adaptability of P. aeruginosa through metabolic conversion. BMC Microbiol 2024; 24:25. [PMID: 38238663 PMCID: PMC10797966 DOI: 10.1186/s12866-023-03175-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2023] [Accepted: 12/26/2023] [Indexed: 01/22/2024] Open
Abstract
BACKGROUND Oligoribonuclease (orn) of P. aeruginosa is a highly conserved exonuclease, which can regulate the global gene expression levels of bacteria through regulation of both the nanoRNA and c-di-GMP. NanoRNA can regulate the expression of the bacterial global genome as a transcription initiator, and c-di-GMP is the most widely second messenger in bacterial cells. OBJECTIVE This study seeks to elucidate on the regulation by orn on pathogenicity of P. aeruginosa. METHODS P. aeruginosa with orn deletion was constructed by suicide plasmid homologous recombination method. The possible regulatory process of orn was analyzed by TMT quantitative labeling proteomics. Then experiments were conducted to verify the changes of Δorn on bacterial motility, virulence and biofilm formation. Bacterial pathogenicity was further detected in cell and animal skin trauma models. ELISA detection c-di-GMP concentration and colony aggregation and biofilm formation were observed by scanning electron microscope. RESULTS orn deletion changed the global metabolism of P. aeruginosa and reduced intracellular energy metabolism. It leads to the disorder of the quorum sensing system, the reduction of bacterial motility and virulence factors pyocyanin and rhamnolipids. But, orn deletion enhanced pathogenicity in vitro and in vivo, a high level of c-di-GMP and biofilm development of P. aeruginosa. CONCLUSION orn regulates the ability of P. aeruginosa to adapt to the external environment.
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Affiliation(s)
- Lulu Yang
- Department of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, 410078, China
- Department of Medical Microbiology, Xiangya School of Medicine, Central South University, Changsha, Hunan, 410078, China
| | - Lili Wang
- Department of Medical Microbiology, Xiangya School of Medicine, Central South University, Changsha, Hunan, 410078, China
| | - Mengyu Wang
- Department of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, 410078, China
- Department of Medical Microbiology, Xiangya School of Medicine, Central South University, Changsha, Hunan, 410078, China
| | - Ousman Bajinka
- Department of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, 410078, China
- Department of Medical Microbiology, Xiangya School of Medicine, Central South University, Changsha, Hunan, 410078, China
| | - Guojun Wu
- Department of Medical Microbiology, Xiangya School of Medicine, Central South University, Changsha, Hunan, 410078, China
| | - Ling Qin
- Department of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, 410078, China.
| | - Yurong Tan
- Department of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, 410078, China.
- Department of Medical Microbiology, Xiangya School of Medicine, Central South University, Changsha, Hunan, 410078, China.
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Espinosa-Urgel M, Ramos-González MI. Becoming settlers: Elements and mechanisms for surface colonization by Pseudomonas putida. Environ Microbiol 2023; 25:1575-1593. [PMID: 37045787 DOI: 10.1111/1462-2920.16385] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 03/31/2023] [Indexed: 04/14/2023]
Abstract
Pseudomonads are considered to be among the most widespread culturable bacteria in mesophilic environments. The evolutive success of Pseudomonas species can be attributed to their metabolic versatility, in combination with a set of additional functions that enhance their ability to colonize different niches. These include the production of secondary metabolites involved in iron acquisition or having a detrimental effect on potential competitors, different types of motility, and the capacity to establish and persist within biofilms. Although biofilm formation has been extensively studied using the opportunistic pathogen Pseudomonas aeruginosa as a model organism, a significant body of knowledge is also becoming available for non-pathogenic Pseudomonas. In this review, we focus on the mechanisms that allow Pseudomonas putida to colonize biotic and abiotic surfaces and adapt to sessile life, as a relevant persistence strategy in the environment. This species is of particular interest because it includes plant-beneficial strains, in which colonization of plant surfaces may be relevant, and strains used for environmental and biotechnological applications, where the design and functionality of biofilm-based bioreactors, for example, also have to take into account the efficiency of bacterial colonization of solid surfaces. This work reviews the current knowledge of mechanistic and regulatory aspects of biofilm formation by P. putida and pinpoints the prospects in this field.
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Affiliation(s)
- Manuel Espinosa-Urgel
- Department of Biotechnology and Environmental Protection, Estación Experimental del Zaidín, Granada, Spain
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Tryptone in Growth Media Enhances Pseudomonas putida Biofilm. Microorganisms 2022; 10:microorganisms10030618. [PMID: 35336191 PMCID: PMC8954664 DOI: 10.3390/microorganisms10030618] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 03/10/2022] [Accepted: 03/11/2022] [Indexed: 11/24/2022] Open
Abstract
Extracellular factors and growth conditions can affect the formation and development of bacterial biofilms. The biofilm of Pseudomonas putida has been studied for decades, but so far, little attention has been paid to the components of the medium that may affect the biofilm development in a closed system. It is known that Fis strongly enhances biofilm in complete LB medium. However, this is not the case in the defined M9 medium, which led us to question why the bacterium behaves differently in these two media. Detailed analysis of the individual medium components revealed that tryptone as the LB proteinaceous component maintains biofilm in its older stages. Although the growth parameters of planktonic cells were similar in the media containing tryptone or an equivalent concentration of amino acids, only the tryptone had a positive effect on the mature biofilm of the wild type strain of P. putida. Thus, the peptides in the environment may influence mature biofilm as a structural factor and not only as an energy source. Testing the effect of other biopolymers on biofilm formation showed variable results even for polymers with a similar charge, indicating that biopolymers can affect P. putida biofilm through a number of bacterial factors.
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Passarelli-Araujo H, Jacobs SH, Franco GR, Venancio TM. Phylogenetic analysis and population structure of Pseudomonas alloputida. Genomics 2021; 113:3762-3773. [PMID: 34530104 DOI: 10.1016/j.ygeno.2021.09.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 07/16/2021] [Accepted: 09/11/2021] [Indexed: 11/26/2022]
Abstract
The Pseudomonas putida group comprises strains with biotechnological and clinical relevance. P. alloputida was proposed as a new species and highlighted the misclassification of P. putida. Nevertheless, the population structure of P. alloputida remained unexplored. We retrieved 11,025 Pseudomonas genomes and used P. alloputida Kh7T to delineate the species. The P. alloputida population structure comprises at least 7 clonal complexes (CCs). Clinical isolates are mainly found in CC4 and acquired resistance genes are present at low frequency in plasmids. Virulence profiles support the potential of CC7 members to outcompete other plant or human pathogens through a type VI secretion system. Finally, we found that horizontal gene transfer had an important role in shaping the ability of P. alloputida to bioremediate aromatic compounds such as toluene. Our results provide the grounds to understand P. alloputida genetic diversity and its potential for biotechnological applications.
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Affiliation(s)
- Hemanoel Passarelli-Araujo
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil; Laboratório de Química e Função de Proteínas e Peptídeos, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, RJ, Brazil.
| | - Sarah H Jacobs
- Laboratório de Química e Função de Proteínas e Peptídeos, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, RJ, Brazil
| | - Glória R Franco
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Thiago M Venancio
- Laboratório de Química e Função de Proteínas e Peptídeos, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, RJ, Brazil.
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Knights HE, Jorrin B, Haskett TL, Poole PS. Deciphering bacterial mechanisms of root colonization. ENVIRONMENTAL MICROBIOLOGY REPORTS 2021; 13:428-444. [PMID: 33538402 PMCID: PMC8651005 DOI: 10.1111/1758-2229.12934] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 01/26/2021] [Accepted: 01/27/2021] [Indexed: 05/07/2023]
Abstract
Bacterial colonization of the rhizosphere is critical for the establishment of plant-bacteria interactions that represent a key determinant of plant health and productivity. Plants influence bacterial colonization primarily through modulating the composition of their root exudates and mounting an innate immune response. The outcome is a horizontal filtering of bacteria from the surrounding soil, resulting in a gradient of reduced bacterial diversity coupled with a higher degree of bacterial specialization towards the root. Bacteria-bacteria interactions (BBIs) are also prevalent in the rhizosphere, influencing bacterial persistence and root colonization through metabolic exchanges, secretion of antimicrobial compounds and other processes. Traditionally, bacterial colonization has been examined under sterile laboratory conditions that mitigate the influence of BBIs. Using simplified synthetic bacterial communities combined with microfluidic imaging platforms and transposon mutagenesis screening approaches, we are now able to begin unravelling the molecular mechanisms at play during the early stages of root colonization. This review explores the current state of knowledge regarding bacterial root colonization and identifies key tools for future exploration.
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Affiliation(s)
| | - Beatriz Jorrin
- Department of Plant SciencesUniversity of OxfordOxfordOX1 3RBUK
| | | | - Philip S. Poole
- Department of Plant SciencesUniversity of OxfordOxfordOX1 3RBUK
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Xu X, Li H, Qi X, Chen Y, Qin Y, Zheng J, Jiang X. cheA, cheB, cheR, cheV, and cheY Are Involved in Regulating the Adhesion of Vibrio harveyi. Front Cell Infect Microbiol 2021; 10:591751. [PMID: 33614522 PMCID: PMC7887938 DOI: 10.3389/fcimb.2020.591751] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 12/01/2020] [Indexed: 11/13/2022] Open
Abstract
Diseases caused by Vibrio harveyi lead to severe economic losses in the aquaculture industry. Adhesion is an important disease-causing factor observed in bacteria with chemotactic activity. In our study, we measured the adhesion of V. harveyi by subjecting the bacteria to stress using Cu2+, Pb2+, Hg2+, and Zn2+. The genes responsible for chemotaxis (cheA, cheB, cheR, cheV, and cheY), which are also crucial for adhesion, were identified and silenced via RNAi. We observed that a decrease in chemotactic gene expression reduced the ability of the organism to demonstrate adhesion, motility, chemotaxis, and biofilm formation. Upon comparing the cheA-RNAi bacteria to the wild-type strain, we observed that the transcriptome of V. harveyi was significantly altered. Additionally, the expression of key genes and the adhesion ability were affected by the pH (pH of 5, 6, 7, 8, and 9), salinity (NaCl at concentrations of 0.8, 1.5, 2.5, 3.5, or 4.5%), and temperature (4, 15, 28, 37, and 44°C) of the medium. Based on these results, the following conclusions were made: (1) The chemotactic genes cheA, cheB, cheR, cheV, and cheY may regulate the adhesion ability of V. harveyi by affecting bacterial motility, and participate in the regulation of adhesion at different temperatures, salinities, and pH values; (2) stable silencing of cheA could alter the transcriptional landscape of V. harveyi and regulate the expression of genes associated with its adhesion mechanisms.
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Affiliation(s)
- Xiaojin Xu
- Fisheries College, Jimei University, Xiamen, China.,Engineering Research Centre of Eel Modern Industrial Technology, Ministry of Education, Xiamen, China.,Jimei University, Xiamen, China.,State Key Laboratory of Large Yellow Croaker Breeding, Ningde Fufa Fisheries Company Limited, Ningde, China.,Fujian Province Key Laboratory of Special Aquatic Formula Feed, Fujian Tianma Science and Technology Group Co., Ltd., Fuzhou, China
| | - Huiyao Li
- Fisheries College, Jimei University, Xiamen, China.,Engineering Research Centre of Eel Modern Industrial Technology, Ministry of Education, Xiamen, China.,Jimei University, Xiamen, China
| | - Xin Qi
- Fisheries College, Jimei University, Xiamen, China.,Engineering Research Centre of Eel Modern Industrial Technology, Ministry of Education, Xiamen, China.,Jimei University, Xiamen, China
| | - Yunong Chen
- Fisheries College, Jimei University, Xiamen, China.,Engineering Research Centre of Eel Modern Industrial Technology, Ministry of Education, Xiamen, China.,Jimei University, Xiamen, China
| | - Yingxue Qin
- Fisheries College, Jimei University, Xiamen, China.,Engineering Research Centre of Eel Modern Industrial Technology, Ministry of Education, Xiamen, China.,Jimei University, Xiamen, China
| | - Jiang Zheng
- Fisheries College, Jimei University, Xiamen, China.,Engineering Research Centre of Eel Modern Industrial Technology, Ministry of Education, Xiamen, China.,Jimei University, Xiamen, China.,State Key Laboratory of Large Yellow Croaker Breeding, Ningde Fufa Fisheries Company Limited, Ningde, China
| | - Xinglong Jiang
- Fisheries College, Jimei University, Xiamen, China.,Engineering Research Centre of Eel Modern Industrial Technology, Ministry of Education, Xiamen, China.,Jimei University, Xiamen, China
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Ma GL, Chandra H, Liang ZX. Taming the flagellar motor of pseudomonads with a nucleotide messenger. Environ Microbiol 2020; 22:2496-2513. [PMID: 32329141 DOI: 10.1111/1462-2920.15036] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 04/20/2020] [Accepted: 04/21/2020] [Indexed: 01/11/2023]
Abstract
Pseudomonads rely on the flagellar motor to rotate a polar flagellum for swimming and swarming, and to sense surfaces for initiating the motile-to-sessile transition to adopt a surface-dwelling lifestyle. Deciphering the function and regulation of the flagellar motor is of paramount importance for understanding the behaviours of environmental and pathogenic pseudomonads. Recent studies disclosed the preeminent role played by the messenger c-di-GMP in controlling the real-time performance of the flagellar motor in pseudomonads. The studies revealed that c-di-GMP controls the dynamic exchange of flagellar stator units to regulate motor torque/speed and modulates the frequency of flagellar motor switching via the chemosensory signalling pathways. Apart from being a rotary motor, the flagellar motor is emerging as a mechanosensor that transduces surface-induced mechanical signals into an increase of cellular c-di-GMP concentration to initiate the cellular programs required for long-term colonization. Collectively, the studies generate long-awaited mechanistic insights into how c-di-GMP regulates bacterial motility and the motile-to-sessile transition. The new findings also raise the fundamental questions of how cellular c-di-GMP concentrations are dynamically coupled to flagellar output and the proton-motive force, and how c-di-GMP signalling is coordinated spatiotemporally to fine-tune flagellar response and the behaviour of pseudomonads in solutions and on surfaces.
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Affiliation(s)
- Guang-Lei Ma
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, S637551, Singapore
| | - Hartono Chandra
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, S637551, Singapore
| | - Zhao-Xun Liang
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, S637551, Singapore.,Singapore Centre for Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, 60 Nanyang Drive, S637551, Singapore
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11
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Quantitative analysis and influences of contact dynamics on bacterial cross-contamination from contaminated fresh produce. J FOOD ENG 2020. [DOI: 10.1016/j.jfoodeng.2019.109771] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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12
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Abstract
Pseudomonas putidais a fast-growing bacterium found mostly in temperate soil and water habitats. The metabolic versatility ofP. putidamakes this organism attractive for biotechnological applications such as biodegradation of environmental pollutants and synthesis of added-value chemicals (biocatalysis). This organism has been extensively studied in respect to various stress responses, mechanisms of genetic plasticity and transcriptional regulation of catabolic genes.P. putidais able to colonize the surface of living organisms, but is generally considered to be of low virulence. A number ofP. putidastrains are able to promote plant growth. The aim of this review is to give historical overview of the discovery of the speciesP. putidaand isolation and characterization ofP. putidastrains displaying potential for biotechnological applications. This review also discusses some major findings inP. putidaresearch encompassing regulation of catabolic operons, stress-tolerance mechanisms and mechanisms affecting evolvability of bacteria under conditions of environmental stress.
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13
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Beaussart A, El-Kirat-Chatel S. Microbial adhesion and ultrastructure from the single-molecule to the single-cell levels by Atomic Force Microscopy. Cell Surf 2019; 5:100031. [PMID: 32743147 PMCID: PMC7389263 DOI: 10.1016/j.tcsw.2019.100031] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 07/04/2019] [Accepted: 07/05/2019] [Indexed: 12/29/2022] Open
Abstract
In the last decades, atomic force microscopy (AFM) has evolved towards an accurate and lasting tool to study the surface of living cells in physiological conditions. Through imaging, single-molecule force spectroscopy and single-cell force spectroscopy modes, AFM allows to decipher at multiple scales the morphology and the molecular interactions taking place at the cell surface. Applied to microbiology, these approaches have been used to elucidate biophysical properties of biomolecules and to directly link the molecular structures to their function. In this review, we describe the main methods developed for AFM-based microbial surface analysis that we illustrate with examples of molecular mechanisms unravelled with unprecedented resolution.
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14
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Radkov AD, Moe LA. A Broad Spectrum Racemase in Pseudomonas putida KT2440 Plays a Key Role in Amino Acid Catabolism. Front Microbiol 2018; 9:1343. [PMID: 30008699 PMCID: PMC6034422 DOI: 10.3389/fmicb.2018.01343] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Accepted: 05/31/2018] [Indexed: 02/02/2023] Open
Abstract
The broad-spectrum amino acid racemase (Alr) of Pseudomonas putida KT2440 preferentially interconverts the l- and d-stereoisomers of Lys and Arg. Despite conservation of broad-spectrum racemases among bacteria, little is known regarding their physiological role. Here we explore potential functional roles for Alr in P. putida KT2440. We demonstrate through cellular fractionation that Alr enzymatic activity is found in the periplasm, consistent with its putative periplasm targeting sequence. Specific activity of Alr is highest during exponential growth, and this activity corresponds with an increased accumulation of d-Lys in the growth medium. An alr gene knockout strain (Δalr) was generated and used to assess potential roles for the alr gene in peptidoglycan structure, producing soluble signaling compounds, and amino acid metabolism. The stationary phase peptidoglycan structure did not differ between wild-type and Δalr strains, indicating that products resulting from Alr activity are not incorporated into peptidoglycan under these conditions. RNA-seq was used to assess differences in the transcriptome between the wild-type and Δalr strains. Genes undergoing differential expression were limited to those involved in amino acid metabolism. The Δalr strain exhibited a limited capacity for catabolism of l-Lys and l-Arg as the sole source of carbon and nitrogen. This is consistent with a predicted role for Alr in catabolism of l-Lys by virtue of its ability to convert l-Lys to d-Lys, which is further catabolized through the l-pipecolate pathway. The metabolic profiles here also implicate Alr in catabolism of l-Arg, although the pathway by which d-Arg is further catabolized is not clear at this time. Overall, data presented here describe the primary role of Alr as important for basic amino acid metabolism.
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Affiliation(s)
- Atanas D Radkov
- Department of Plant and Soil Sciences, College of Agriculture, University of Kentucky, Lexington, KY, United States
| | - Luke A Moe
- Department of Plant and Soil Sciences, College of Agriculture, University of Kentucky, Lexington, KY, United States
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15
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Som Chaudhury S, Das Mukhopadhyay C. Functional amyloids: interrelationship with other amyloids and therapeutic assessment to treat neurodegenerative diseases. Int J Neurosci 2017; 128:449-463. [PMID: 29076790 DOI: 10.1080/00207454.2017.1398153] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Sutapa Som Chaudhury
- Centre for Healthcare Science and Technology, Indian Institute of Engineering Science and Technology, Shibpur, West Bengal, India
| | - Chitrangada Das Mukhopadhyay
- Centre for Healthcare Science and Technology, Indian Institute of Engineering Science and Technology, Shibpur, West Bengal, India
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16
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Ainelo H, Lahesaare A, Teppo A, Kivisaar M, Teras R. The promoter region of lapA and its transcriptional regulation by Fis in Pseudomonas putida. PLoS One 2017; 12:e0185482. [PMID: 28945818 PMCID: PMC5612765 DOI: 10.1371/journal.pone.0185482] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 09/13/2017] [Indexed: 12/28/2022] Open
Abstract
LapA is the biggest protein in Pseudomonas putida and a key factor for biofilm formation. Its importance and posttranslational regulation is rather thoroughly studied but less is known about the transcriptional regulation. Here we give evidence that transcription of lapA in LB-grown bacteria is initiated from six promoters, three of which display moderate RpoS-dependence. The global transcription regulator Fis binds to the lapA promoter area at six positions in vitro, and Fis activates the transcription of lapA while overexpressed in cells. Two of the six Fis binding sites, Fis-A7 and Fis-A5, are necessary for the positive effect of Fis on the transcription of lapA in vivo. Our results indicate that Fis binding to the Fis-A7 site increases the level of transcription from the most distal promoter of lapA, whereas Fis binding to the Fis-A5 site could be important for modifying the promoter area topology.
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Affiliation(s)
- Hanna Ainelo
- Chair of Genetics, Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | - Andrio Lahesaare
- Chair of Genetics, Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | - Annika Teppo
- Chair of Genetics, Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | - Maia Kivisaar
- Chair of Genetics, Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | - Riho Teras
- Chair of Genetics, Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
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17
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Guilhen C, Forestier C, Balestrino D. Biofilm dispersal: multiple elaborate strategies for dissemination of bacteria with unique properties. Mol Microbiol 2017; 105:188-210. [PMID: 28422332 DOI: 10.1111/mmi.13698] [Citation(s) in RCA: 110] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/15/2017] [Indexed: 01/22/2023]
Abstract
In most environments, microorganisms evolve in a sessile mode of growth, designated as biofilm, which is characterized by cells embedded in a self-produced extracellular matrix. Although a biofilm is commonly described as a "cozy house" where resident bacteria are protected from aggression, bacteria are able to break their biofilm bonds and escape to colonize new environments. This regulated process is observed in a wide variety of species; it is referred to as biofilm dispersal, and is triggered in response to various environmental and biological signals. The first part of this review reports the main regulatory mechanisms and effectors involved in biofilm dispersal. There is some evidence that dispersal is a necessary step between the persistence of bacteria inside biofilm and their dissemination. In the second part, an overview of the main methods used so far to study the dispersal process and to harvest dispersed bacteria was provided. Then focus was on the properties of the biofilm-dispersed bacteria and the fundamental role of the dispersal process in pathogen dissemination within a host organism. In light of the current body of knowledge, it was suggested that dispersal acts as a potent means of disseminating bacteria with enhanced colonization properties in the surrounding environment.
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Affiliation(s)
- Cyril Guilhen
- Laboratoire Microorganismes : Génome et Environnement, UMR CNRS 6023, Université Clermont Auvergne, Clermont Ferrand, F-63001, France
| | - Christiane Forestier
- Laboratoire Microorganismes : Génome et Environnement, UMR CNRS 6023, Université Clermont Auvergne, Clermont Ferrand, F-63001, France
| | - Damien Balestrino
- Laboratoire Microorganismes : Génome et Environnement, UMR CNRS 6023, Université Clermont Auvergne, Clermont Ferrand, F-63001, France
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18
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Xiao Y, Nie H, Liu H, Luo X, Chen W, Huang Q. C-di-GMP regulates the expression of lapA and bcs operons via FleQ in Pseudomonas putida KT2440. ENVIRONMENTAL MICROBIOLOGY REPORTS 2016; 8:659-666. [PMID: 27120564 DOI: 10.1111/1758-2229.12419] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2016] [Accepted: 04/21/2016] [Indexed: 06/05/2023]
Abstract
Cyclic diguanylate (c-di-GMP) positively modulates the production of biofilm matrix components from the transcriptional to the post-translational level in a variety of bacterial species. However, mechanisms by which it regulates these opponents in Pseudomonas putida KT2440 remain unclear. Here we show that c-di-GMP regulates the adhesin LapA, LapF and exopolysaccharides Bcs, Pea at transcriptional level. Transcriptional regulator FleQ is required for the modulation of lapA and bcs expression by c-di-GMP, but seems not to be necessary for that of lapF and pea. We also found that fleQ mutant of P. putida was defective in biofilm formation and had smooth colony morphology. Transcription assay indicates that FleQ acts as an activator of lapA, but a repressor of bcs. In vitro experiments show that FleQ binds to lapA and bcs promoter DNA. The binding to lapA promoter was slightly promoted by c-di-GMP, while binding to bcs promoter was inhibited by c-di-GMP. Our results show that c-di-GMP regulates the expression of lapA and bcs operons via FleQ in P. putida.
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Affiliation(s)
- Yujie Xiao
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Hailing Nie
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Huizhong Liu
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Xuesong Luo
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, China
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China
| | - Wenli Chen
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Qiaoyun Huang
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, China
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China
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19
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Luo G, Huang L, Su Y, Qin Y, Xu X, Zhao L, Yan Q. flrA, flrB and flrC regulate adhesion by controlling the expression of critical virulence genes in Vibrio alginolyticus. Emerg Microbes Infect 2016; 5:e85. [PMID: 27485498 PMCID: PMC5034100 DOI: 10.1038/emi.2016.82] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 05/12/2016] [Accepted: 05/16/2016] [Indexed: 12/24/2022]
Abstract
Adhesion is an important virulence trait of Vibrio alginolyticus. Bacterial adhesion is influenced by environmental conditions; however, the molecular mechanism underlying this effect remains unknown. The expression levels of flrA, flrB and flrC were significantly downregulated in adhesion-deficient V. alginolyticus strains cultured under Cu2+, Pb2+, Hg2+ and low-pH stresses. Silencing these genes led to deficiencies in adhesion, motility, flagellar assembly, biofilm formation and exopolysaccharide (EPS) production. The expression levels of fliA, flgH, fliS, fliD, cheR, cheV and V12G01_22158 (Gene ID) were significantly downregulated in all of the RNAi groups, whereas the expression levels of toxT, ctxB, acfA, hlyA and tlh were upregulated in flrA- and flrC-silenced groups. These genes play a key role in the virulence mechanisms of most pathogenic Vibrio species. Furthermore, the expression of flrA, flrB and flrC was significantly influenced by temperature, salinity, starvation and pH. These results indicate that (1) flrA, flrB and flrC are important for V. alginolyticus adhesion; (2) flrA, flrB and flrC significantly influence bacterial adhesion, motility, biofilm formation and EPS production by controlling expression of key genes involved in those phenotypes; and (3) flrA, flrB and flrC regulate adhesion in the natural environment with different temperatures, pH levels, salinities and starvation time.
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Affiliation(s)
- Gang Luo
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, Fujian 361021, China
| | - Lixing Huang
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, Fujian 361021, China
| | - Yongquan Su
- College of Ocean and Earth Sciences, Xiamen University, Xiamen, Fujian 361102, China.,State Key Laboratory of Large Yellow Croaker Breeding, Ningde, Fujian 352000, China
| | - Yingxue Qin
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, Fujian 361021, China
| | - Xiaojin Xu
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, Fujian 361021, China
| | - Lingmin Zhao
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, Fujian 361021, China
| | - Qingpi Yan
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, Fujian 361021, China.,State Key Laboratory of Large Yellow Croaker Breeding, Ningde, Fujian 352000, China
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20
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Fox AR, Soto G, Valverde C, Russo D, Lagares A, Zorreguieta Á, Alleva K, Pascuan C, Frare R, Mercado-Blanco J, Dixon R, Ayub ND. Major cereal crops benefit from biological nitrogen fixation when inoculated with the nitrogen-fixing bacterium Pseudomonas protegens Pf-5 X940. Environ Microbiol 2016; 18:3522-3534. [PMID: 27198923 DOI: 10.1111/1462-2920.13376] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
A main goal of biological nitrogen fixation research has been to expand the nitrogen-fixing ability to major cereal crops. In this work, we demonstrate the use of the efficient nitrogen-fixing rhizobacterium Pseudomonas protegens Pf-5 X940 as a chassis to engineer the transfer of nitrogen fixed by BNF to maize and wheat under non-gnotobiotic conditions. Inoculation of maize and wheat with Pf-5 X940 largely improved nitrogen content and biomass accumulation in both vegetative and reproductive tissues, and this beneficial effect was positively associated with high nitrogen fixation rates in roots. 15 N isotope dilution analysis showed that maize and wheat plants obtained substantial amounts of fixed nitrogen from the atmosphere. Pf-5 X940-GFP-tagged cells were always reisolated from the maize and wheat root surface but never from the inner root tissues. Confocal laser scanning microscopy confirmed root surface colonization of Pf-5 X940-GFP in wheat plants, and microcolonies were mostly visualized at the junctions between epidermal root cells. Genetic analysis using biofilm formation-related Pseudomonas mutants confirmed the relevance of bacterial root adhesion in the increase in nitrogen content, biomass accumulation and nitrogen fixation rates in wheat roots. To our knowledge, this is the first report of robust BNF in major cereal crops.
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Affiliation(s)
- Ana Romina Fox
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Cuidad Autónoma de Buenos Aires, Buenos Aires, Argentina.,Instituto de Genética Ewald A. Favret (CICVyA-INTA), Buenos Aires, Argentina
| | - Gabriela Soto
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Cuidad Autónoma de Buenos Aires, Buenos Aires, Argentina.,Instituto de Genética Ewald A. Favret (CICVyA-INTA), Buenos Aires, Argentina
| | - Claudio Valverde
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Cuidad Autónoma de Buenos Aires, Buenos Aires, Argentina.,LBMIBS, Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes, Buenos Aires, Argentina
| | - Daniela Russo
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Cuidad Autónoma de Buenos Aires, Buenos Aires, Argentina.,Fundación Instituto Leloir and IIBBA CONICET, Buenos Aires, Argentina
| | - Antonio Lagares
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Cuidad Autónoma de Buenos Aires, Buenos Aires, Argentina.,LBMIBS, Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes, Buenos Aires, Argentina
| | - Ángeles Zorreguieta
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Cuidad Autónoma de Buenos Aires, Buenos Aires, Argentina.,Fundación Instituto Leloir and IIBBA CONICET, Buenos Aires, Argentina
| | - Karina Alleva
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Cuidad Autónoma de Buenos Aires, Buenos Aires, Argentina.,Departamento de Fisicomatemática, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Cecilia Pascuan
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Cuidad Autónoma de Buenos Aires, Buenos Aires, Argentina.,Instituto de Genética Ewald A. Favret (CICVyA-INTA), Buenos Aires, Argentina
| | - Romina Frare
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Cuidad Autónoma de Buenos Aires, Buenos Aires, Argentina.,Instituto de Genética Ewald A. Favret (CICVyA-INTA), Buenos Aires, Argentina
| | - Jesús Mercado-Blanco
- Department of Crop Protection, Institute for Sustainable Agriculture, Agencia Estatal Consejo Superior de Investigaciones Científicas (CSIC), Córdoba, Spain
| | - Ray Dixon
- Department of Molecular Microbiology, John Innes Centre, Norwich, NR4 7UH, UK
| | - Nicolás Daniel Ayub
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Cuidad Autónoma de Buenos Aires, Buenos Aires, Argentina. .,Instituto de Genética Ewald A. Favret (CICVyA-INTA), Buenos Aires, Argentina.
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21
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Boukerb AM, Decor A, Ribun S, Tabaroni R, Rousset A, Commin L, Buff S, Doléans-Jordheim A, Vidal S, Varrot A, Imberty A, Cournoyer B. Genomic Rearrangements and Functional Diversification of lecA and lecB Lectin-Coding Regions Impacting the Efficacy of Glycomimetics Directed against Pseudomonas aeruginosa. Front Microbiol 2016; 7:811. [PMID: 27303392 PMCID: PMC4885879 DOI: 10.3389/fmicb.2016.00811] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Accepted: 05/12/2016] [Indexed: 11/13/2022] Open
Abstract
LecA and LecB tetrameric lectins take part in oligosaccharide-mediated adhesion-processes of Pseudomonas aeruginosa. Glycomimetics have been designed to block these interactions. The great versatility of P. aeruginosa suggests that the range of application of these glycomimetics could be restricted to genotypes with particular lectin types. The likelihood of having genomic and genetic changes impacting LecA and LecB interactions with glycomimetics such as galactosylated and fucosylated calix[4]arene was investigated over a collection of strains from the main clades of P. aeruginosa. Lectin types were defined, and their ligand specificities were inferred. These analyses showed a loss of lecA among the PA7 clade. Genomic changes impacting lec loci were thus assessed using strains of this clade, and by making comparisons with the PAO1 genome. The lecA regions were found challenged by phage attacks and PAGI-2 (genomic island) integrations. A prophage was linked to the loss of lecA. The lecB regions were found less impacted by such rearrangements but greater lecB than lecA genetic divergences were recorded. Sixteen combinations of LecA and LecB types were observed. Amino acid variations were mapped on PAO1 crystal structures. Most significant changes were observed on LecBPA7, and found close to the fucose binding site. Glycan array analyses were performed with purified LecBPA7. LecBPA7 was found less specific for fucosylated oligosaccharides than LecBPAO1, with a preference for H type 2 rather than type 1, and Lewis(a) rather than Lewis(x). Comparison of the crystal structures of LecBPA7 and LecBPAO1 in complex with Lewis(a) showed these changes in specificity to have resulted from a modification of the water network between the lectin, galactose and GlcNAc residues. Incidence of these modifications on the interactions with calix[4]arene glycomimetics at the cell level was investigated. An aggregation test was used to establish the efficacy of these ligands. Great variations in the responses were observed. Glycomimetics directed against LecB yielded the highest numbers of aggregates for strains from all clades. The use of a PAO1ΔlecB strain confirmed a role of LecB in this aggregation phenotype. Fucosylated calix[4]arene showed the greatest potential for a use in the prevention of P. aeruginosa infections.
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Affiliation(s)
- Amine M Boukerb
- Equipes de Recherche, Bactéries Pathogènes Opportunistes et Environnement, Centre de Ressources Biologiques - Environnement Microbiologie Lyon, UMR Centre National de la Recherche Scientifique 5557 Ecologie Microbienne, Université Lyon 1 and VetAgro Sup Lyon, France
| | - Aude Decor
- Centre de Recherche sur les Macromolécules Végétales (UPR 5301), Centre National de la Recherche Scientifique and Université Grenoble Alpes Grenoble, France
| | - Sébastien Ribun
- Equipes de Recherche, Bactéries Pathogènes Opportunistes et Environnement, Centre de Ressources Biologiques - Environnement Microbiologie Lyon, UMR Centre National de la Recherche Scientifique 5557 Ecologie Microbienne, Université Lyon 1 and VetAgro Sup Lyon, France
| | - Rachel Tabaroni
- Centre de Recherche sur les Macromolécules Végétales (UPR 5301), Centre National de la Recherche Scientifique and Université Grenoble Alpes Grenoble, France
| | - Audric Rousset
- Laboratoire de Chimie Organique 2 - Glycochimie, Institut de Chimie et Biochimie Moléculaires et Supramoléculaires, UMR Centre National de la Recherche Scientifique 5246, Université Lyon 1 Lyon, France
| | - Loris Commin
- Université de Lyon, VetAgro Sup, UPSP 2011-03-101, Interactions Cellules Environnement and CRB-ANIM (ANR-INBS11-0003) Marcy-L'Etoile, France
| | - Samuel Buff
- Université de Lyon, VetAgro Sup, UPSP 2011-03-101, Interactions Cellules Environnement and CRB-ANIM (ANR-INBS11-0003) Marcy-L'Etoile, France
| | - Anne Doléans-Jordheim
- Equipes de Recherche, Bactéries Pathogènes Opportunistes et Environnement, Centre de Ressources Biologiques - Environnement Microbiologie Lyon, UMR Centre National de la Recherche Scientifique 5557 Ecologie Microbienne, Université Lyon 1 and VetAgro Sup Lyon, France
| | - Sébastien Vidal
- Laboratoire de Chimie Organique 2 - Glycochimie, Institut de Chimie et Biochimie Moléculaires et Supramoléculaires, UMR Centre National de la Recherche Scientifique 5246, Université Lyon 1 Lyon, France
| | - Annabelle Varrot
- Centre de Recherche sur les Macromolécules Végétales (UPR 5301), Centre National de la Recherche Scientifique and Université Grenoble Alpes Grenoble, France
| | - Anne Imberty
- Centre de Recherche sur les Macromolécules Végétales (UPR 5301), Centre National de la Recherche Scientifique and Université Grenoble Alpes Grenoble, France
| | - Benoit Cournoyer
- Equipes de Recherche, Bactéries Pathogènes Opportunistes et Environnement, Centre de Ressources Biologiques - Environnement Microbiologie Lyon, UMR Centre National de la Recherche Scientifique 5557 Ecologie Microbienne, Université Lyon 1 and VetAgro Sup Lyon, France
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22
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López-Sánchez A, Leal-Morales A, Jiménez-Díaz L, Platero AI, Bardallo-Pérez J, Díaz-Romero A, Acemel RD, Illán JM, Jiménez-López J, Govantes F. Biofilm formation-defective mutants in Pseudomonas putida. FEMS Microbiol Lett 2016; 363:fnw127. [PMID: 27190143 DOI: 10.1093/femsle/fnw127] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/09/2016] [Indexed: 02/07/2023] Open
Abstract
Out of 8000 candidates from a genetic screening for Pseudomonas putida KT2442 mutants showing defects in biofilm formation, 40 independent mutants with diminished levels of biofilm were analyzed. Most of these mutants carried insertions in genes of the lap cluster, whose products are responsible for synthesis, export and degradation of the adhesin LapA. All mutants in this class were strongly defective in biofilm formation. Mutants in the flagellar regulatory genes fleQ and flhF showed similar defects to that of the lap mutants. On the contrary, transposon insertions in the flagellar structural genes fliP and flgG, that also impair flagellar motility, had a modest defect in biofilm formation. A mutation in gacS, encoding the sensor element of the GacS/GacA two-component system, also had a moderate effect on biofilm formation. Additional insertions targeted genes involved in cell envelope function: PP3222, encoding the permease element of an ABC-type transporter and tolB, encoding the periplasmic component of the Tol-OprL system required for outer membrane stability. Our results underscore the central role of LapA, suggest cross-regulation between motility and adhesion functions and provide insights on the role of cell envelope trafficking and maintenance for biofilm development in P. putida.
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Affiliation(s)
- Aroa López-Sánchez
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide/Consejo Superior de Investigaciones Científicas/Junta de Andalucía, and Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide
| | - Antonio Leal-Morales
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide/Consejo Superior de Investigaciones Científicas/Junta de Andalucía, and Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide
| | - Lorena Jiménez-Díaz
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide/Consejo Superior de Investigaciones Científicas/Junta de Andalucía, and Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide
| | - Ana I Platero
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide/Consejo Superior de Investigaciones Científicas/Junta de Andalucía, and Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide
| | - Juan Bardallo-Pérez
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide/Consejo Superior de Investigaciones Científicas/Junta de Andalucía, and Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide
| | - Alberto Díaz-Romero
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide/Consejo Superior de Investigaciones Científicas/Junta de Andalucía, and Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide
| | - Rafael D Acemel
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide/Consejo Superior de Investigaciones Científicas/Junta de Andalucía, and Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide
| | - Juan M Illán
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide/Consejo Superior de Investigaciones Científicas/Junta de Andalucía, and Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide
| | - Julia Jiménez-López
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide/Consejo Superior de Investigaciones Científicas/Junta de Andalucía, and Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide
| | - Fernando Govantes
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide/Consejo Superior de Investigaciones Científicas/Junta de Andalucía, and Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide
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23
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Abstract
During the first step of biofilm formation, initial attachment is dictated by physicochemical and electrostatic interactions between the surface and the bacterial envelope. Depending on the nature of these interactions, attachment can be transient or permanent. To achieve irreversible attachment, bacterial cells have developed a series of surface adhesins promoting specific or nonspecific adhesion under various environmental conditions. This article reviews the recent advances in our understanding of the secretion, assembly, and regulation of the bacterial adhesins during biofilm formation, with a particular emphasis on the fimbrial, nonfimbrial, and discrete polysaccharide adhesins in Gram-negative bacteria.
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24
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The LasB Elastase of Pseudomonas aeruginosa Acts in Concert with Alkaline Protease AprA To Prevent Flagellin-Mediated Immune Recognition. Infect Immun 2015; 84:162-71. [PMID: 26502908 DOI: 10.1128/iai.00939-15] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 10/16/2015] [Indexed: 01/02/2023] Open
Abstract
The opportunistic pathogen Pseudomonas aeruginosa is capable of establishing severe and persistent infections in various eukaryotic hosts. It encodes a wide array of virulence factors and employs several strategies to evade immune detection. In the present study, we screened the Harvard Medical School transposon mutant library of P. aeruginosa PA14 for bacterial factors that modulate interleukin-8 responses in A549 human airway epithelial cells. We found that in addition to the previously identified alkaline protease AprA, the elastase LasB is capable of degrading exogenous flagellin under calcium-replete conditions and prevents flagellin-mediated immune recognition. Our results indicate that the production of two proteases with anti-flagellin activity provides a failsafe mechanism for P. aeruginosa to ensure the maintenance of protease-dependent immune-modulating functions.
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Zeng G, Vad BS, Dueholm MS, Christiansen G, Nilsson M, Tolker-Nielsen T, Nielsen PH, Meyer RL, Otzen DE. Functional bacterial amyloid increases Pseudomonas biofilm hydrophobicity and stiffness. Front Microbiol 2015; 6:1099. [PMID: 26500638 PMCID: PMC4595789 DOI: 10.3389/fmicb.2015.01099] [Citation(s) in RCA: 110] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 09/22/2015] [Indexed: 12/20/2022] Open
Abstract
The success of Pseudomonas species as opportunistic pathogens derives in great part from their ability to form stable biofilms that offer protection against chemical and mechanical attack. The extracellular matrix of biofilms contains numerous biomolecules, and it has recently been discovered that in Pseudomonas one of the components includes β-sheet rich amyloid fibrils (functional amyloid) produced by the fap operon. However, the role of the functional amyloid within the biofilm has not yet been investigated in detail. Here we investigate how the fap-based amyloid produced by Pseudomonas affects biofilm hydrophobicity and mechanical properties. Using atomic force microscopy imaging and force spectroscopy, we show that the amyloid renders individual cells more resistant to drying and alters their interactions with hydrophobic probes. Importantly, amyloid makes Pseudomonas more hydrophobic and increases biofilm stiffness 20-fold. Deletion of any one of the individual members of in the fap operon (except the putative chaperone FapA) abolishes this ability to increase biofilm stiffness and correlates with the loss of amyloid. We conclude that amyloid makes major contributions to biofilm mechanical robustness.
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Affiliation(s)
- Guanghong Zeng
- Interdisciplinary Nanoscience Centre, Aarhus UniversityAarhus, Denmark
| | - Brian S. Vad
- Interdisciplinary Nanoscience Centre, Aarhus UniversityAarhus, Denmark
| | - Morten S. Dueholm
- Center for Microbial Communities, Aalborg UniversityAalborg, Denmark
| | - Gunna Christiansen
- Department of Biomedicine-Medical Microbiology and Immunology, Aarhus UniversityAarhus, Denmark
| | - Martin Nilsson
- Department of Immunology and Microbiology, Costerton Biofilm Center, Faculty of Health and Medical Sciences, University of CopenhagenCopenhagen, Denmark
| | - Tim Tolker-Nielsen
- Department of Immunology and Microbiology, Costerton Biofilm Center, Faculty of Health and Medical Sciences, University of CopenhagenCopenhagen, Denmark
| | - Per H. Nielsen
- Center for Microbial Communities, Aalborg UniversityAalborg, Denmark
| | - Rikke L. Meyer
- Interdisciplinary Nanoscience Centre, Aarhus UniversityAarhus, Denmark
| | - Daniel E. Otzen
- Interdisciplinary Nanoscience Centre, Aarhus UniversityAarhus, Denmark
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Udaondo Z, Molina L, Segura A, Duque E, Ramos JL. Analysis of the core genome and pangenome ofPseudomonas putida. Environ Microbiol 2015; 18:3268-3283. [DOI: 10.1111/1462-2920.13015] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 08/04/2015] [Accepted: 08/06/2015] [Indexed: 11/30/2022]
Affiliation(s)
- Zulema Udaondo
- Biotechnology Technological Area; Abengoa Research; Calle Energía Solar 1, Building E, Campus Palmas Altas 41014 Sevilla Spain
| | - Lázaro Molina
- Department of Environmental Protection; Estación Experimental del Zaidín; Consejo Superior de Investigaciones Científicas. C/ Profesor Albareda 1 18008 Granada Spain
| | - Ana Segura
- Biotechnology Technological Area; Abengoa Research; Calle Energía Solar 1, Building E, Campus Palmas Altas 41014 Sevilla Spain
| | - Estrella Duque
- Biotechnology Technological Area; Abengoa Research; Calle Energía Solar 1, Building E, Campus Palmas Altas 41014 Sevilla Spain
| | - Juan L. Ramos
- Biotechnology Technological Area; Abengoa Research; Calle Energía Solar 1, Building E, Campus Palmas Altas 41014 Sevilla Spain
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A three-step method for analysing bacterial biofilm formation under continuous medium flow. Appl Microbiol Biotechnol 2015; 99:6035-47. [PMID: 25936379 DOI: 10.1007/s00253-015-6628-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 04/15/2015] [Accepted: 04/18/2015] [Indexed: 10/23/2022]
Abstract
For the investigation and comparison of microbial biofilms, a variety of analytical methods have been established, all focusing on different growth stages and application areas of biofilms. In this study, a novel quantitative assay for analysing biofilm maturation under the influence of continuous flow conditions was developed using the interesting biocatalyst Pseudomonas taiwanensis VLB120. In contrast to other tubular-based assay systems, this novel assay format delivers three readouts using a single setup in a total assay time of 40 h. It combines morphotype analysis of biofilm colonies with the direct quantification of biofilm biomass and pellicle formation on an air/liquid interphase. Applying the Tube-Assay, the impact of the second messenger cyclic diguanylate on biofilm formation of P. taiwanensis VLB120 was investigated. To this end, 41 deletions of genes encoding for protein homologues to diguanylate cyclase and phosphodiesterase were generated in the genome of P. taiwanensis VLB120. Subsequently, the biofilm formation of the resulting mutants was analysed using the Tube-Assay. In more than 60 % of the mutants, a significantly altered biofilm formation as compared to the parent strain was detected. Furthermore, the potential of the proposed Tube-Assay was validated by investigating the biofilms of several other bacterial species.
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Molina-Santiago C, Udaondo Z, Ramos JL. Draft whole-genome sequence of the antibiotic-producing soil isolate Pseudomonas sp. strain 250J. ENVIRONMENTAL MICROBIOLOGY REPORTS 2015; 7:288-292. [PMID: 25403737 DOI: 10.1111/1758-2229.12245] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Accepted: 10/16/2014] [Indexed: 06/04/2023]
Abstract
Bacteria of the genus Pseudomonas are becoming increasing well known for their ability to produce a wide range of antimicrobial compounds. In a large-scale screening for antibiotic producers, we identified a soil isolate that uses 4-hydroxyphenylacetate as the sole carbon source, Pseudomonas sp. strain 250J, which produces cyclic lipodepsipeptides of the xantholysin family during the stationary phase of growth. The closest relatives of this strain are Pseudomonas mosselii, Pseudomonas soli and Pseudomonas entomophila. Sequencing of the 250J genome allowed us to find the genes relevant to antibiotic production, those which allow utilization of 4-hydroxyphenylacetate as a sole carbon source and a set of genes potentially involved in biocontrol.
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Affiliation(s)
- Carlos Molina-Santiago
- Department of Environmental Protection, Consejo Superior de Investigaciones Científicas (CSIC-EEZ), Granada, 18008, Spain
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29
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Zhurina MV, Gannesen AV, Zdorovenko EL, Plakunov VK. Composition and functions of the extracellular polymer matrix of bacterial biofilms. Microbiology (Reading) 2014. [DOI: 10.1134/s002626171406023x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
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30
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Moor H, Teppo A, Lahesaare A, Kivisaar M, Teras R. Fis overexpression enhances Pseudomonas putida biofilm formation by regulating the ratio of LapA and LapF. MICROBIOLOGY-SGM 2014; 160:2681-2693. [PMID: 25253613 DOI: 10.1099/mic.0.082503-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Bacteria form biofilm as a response to a number of environmental signals that are mediated by global transcription regulators and alarmones. Here we report the involvement of the global transcription regulator Fis in Pseudomonas putida biofilm formation through regulation of lapA and lapF genes. The major component of P. putida biofilm is proteinaceous and two large adhesive proteins, LapA and LapF, are known to play a key role in its formation. We have previously shown that Fis overexpression enhances P. putida biofilm formation. In this study, we used mini-Tn5 transposon mutagenesis to select potential Fis-regulated genes involved in biofilm formation. A total of 90 % of the studied transposon mutants carried insertions in the lap genes. Since our experiments showed that Fis-enhanced biofilm is mostly proteinaceous, the amounts of LapA and LapF from P. putida cells lysates were quantified using SDS-PAGE. Fis overexpression increases the quantity of LapA 1.6 times and decreases the amount of LapF at least 4 times compared to the wild-type cells. The increased LapA expression caused by Fis overexpression was confirmed by FACS analysis measuring the amount of LapA-GFP fusion protein. Our results suggest that the profusion of LapA in the Fis-overexpressed cells causes enhanced biofilm formation in mature stages of P. putida biofilm and LapF has a minor role in P. putida biofilm formation.
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Affiliation(s)
- Hanna Moor
- Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia
| | - Annika Teppo
- Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia
| | - Andrio Lahesaare
- Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia
| | - Maia Kivisaar
- Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia
| | - Riho Teras
- Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia
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Neznansky A, Blus-Kadosh I, Yerushalmi G, Banin E, Opatowsky Y. The Pseudomonas aeruginosa phosphate transport protein PstS plays a phosphate-independent role in biofilm formation. FASEB J 2014; 28:5223-33. [PMID: 25223609 DOI: 10.1096/fj.14-258293] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Pseudomonas aeruginosa (PA) is a primary cause of nosocomial infections. A key element in PA pathogenicity is its ability to form biofilms that withstand eradication by antibiotics and the immune system. Biofilm formation is controlled by phosphate signaling and here we provide evidence that PstS, a subunit of the PA Pst phosphate transporter, has a surprising role in this process. Using X-ray crystallography, we characterized the unique underpinnings of PstS phosphate binding and identified an unusual 15-residue N' loop extension. Structure-based experiments showed that PstS-mediated phosphate uptake and biofilm formation are in fact two distinct functions. Specifically, a point mutation that abrogated phosphate binding did not eliminate biofilm formation; conversely, truncation of the N' loop diminished the ability of PA to form biofilms but had no effect on phosphate binding and uptake. This places PstS at a junction that separately controls phosphate sensing and uptake and the ultrastructure organization of bacteria.
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Affiliation(s)
- Avi Neznansky
- Mina and Everard Goodman Faculty of Life Sciences and
| | - Inna Blus-Kadosh
- Mina and Everard Goodman Faculty of Life Sciences and Advanced Materials and Nanotechnology Institute, Bar-Ilan University, Ramat-Gan, Israel
| | - Gal Yerushalmi
- Mina and Everard Goodman Faculty of Life Sciences and Advanced Materials and Nanotechnology Institute, Bar-Ilan University, Ramat-Gan, Israel
| | - Ehud Banin
- Mina and Everard Goodman Faculty of Life Sciences and Advanced Materials and Nanotechnology Institute, Bar-Ilan University, Ramat-Gan, Israel
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Fazli M, Almblad H, Rybtke ML, Givskov M, Eberl L, Tolker-Nielsen T. Regulation of biofilm formation in Pseudomonas and Burkholderia species. Environ Microbiol 2014; 16:1961-81. [PMID: 24592823 DOI: 10.1111/1462-2920.12448] [Citation(s) in RCA: 190] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 02/12/2014] [Accepted: 02/28/2014] [Indexed: 01/28/2023]
Abstract
In the present review, we describe and compare the molecular mechanisms that are involved in the regulation of biofilm formation by Pseudomonas putida, Pseudomonas fluorescens, Pseudomonas aeruginosa and Burkholderia cenocepacia. Our current knowledge suggests that biofilm formation is regulated by cyclic diguanosine-5'-monophosphate (c-di-GMP), small RNAs (sRNA) and quorum sensing (QS) in all these bacterial species. The systems that employ c-di-GMP as a second messenger regulate the production of exopolysaccharides and surface proteins which function as extracellular matrix components in the biofilms formed by the bacteria. The systems that make use of sRNAs appear to regulate the production of exopolysaccharide biofilm matrix material in all these species. In the pseudomonads, QS regulates the production of extracellular DNA, lectins and biosurfactants which all play a role in biofilm formation. In B.cenocepacia QS regulates the expression of a large surface protein, lectins and extracellular DNA that all function as biofilm matrix components. Although the three regulatory systems all regulate the production of factors used for biofilm formation, the molecular mechanisms involved in transducing the signals into expression of the biofilm matrix components differ between the species. Under the conditions tested, exopolysaccharides appears to be the most important biofilm matrix components for P.aeruginosa, whereas large surface proteins appear to be the most important biofilm matrix components for P.putida, P.fluorescens, and B.cenocepacia.
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Affiliation(s)
- Mustafa Fazli
- Department of International Health, Immunology, and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Department of Biology, Faculty of Science, University of Copenhagen, Copenhagen, Denmark; Department of Genetics and Bioengineering, Faculty of Engineering and Architecture, Yeditepe University, Istanbul, Turkey
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El-Kirat-Chatel S, Boyd CD, O'Toole GA, Dufrêne YF. Single-molecule analysis of Pseudomonas fluorescens footprints. ACS NANO 2014; 8:1690-1698. [PMID: 24456070 PMCID: PMC4936413 DOI: 10.1021/nn4060489] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Understanding the molecular mechanisms of bacterial adhesion and biofilm formation is an important topic in current microbiology and a key in nanomedicine for developing new antibacterial strategies. There is growing evidence that the production of extracellular polymeric substances at the cell-substrate interface plays a key role in strengthening bacterial adhesion. Yet, because these adhesive polymers are available in small amounts and are localized at interfaces, they are difficult to study using traditional techniques. Here, we use single-molecule atomic force microscopy (AFM) to functionally analyze the biophysical properties (distribution, adhesion, and extension) of bacterial footprints, that is, adhesive macromolecules left on substrate surfaces after removal of the attached cells. We focus on the large adhesin protein LapA from Pseudomonas fluorescens, which mediates cell attachment to a wide diversity of surfaces. Using AFM tips functionalized with specific antibodies, we demonstrate that adhesion of bacteria to hydrophobic substrates leads to the active accumulation of the LapA protein at the cell-substrate interface. We show that single LapA proteins left on the substrate after cell detachment localize into microscale domains corresponding to the bacterial size and exhibit multiple adhesion peaks reflecting the adhesion and extension of adsorbed LapA proteins. The mechanical behavior of LapA-based footprints makes them ideally suited to function as multipurpose bridging polymers, enabling P. fluorescens to attach to various surfaces. Our experiments show that single-molecule AFM offers promising prospects for characterizing the biophysics and dynamics of the cell-substrate interface in the context of bacterial adhesion, on a scale that was not accessible before.
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Affiliation(s)
- Sofiane El-Kirat-Chatel
- Institute of Life Sciences, Université catholique de Louvain, Croix du Sud, 1, bte L7.04.01, B-1348 Louvain-la-Neuve, Belgium
| | - Chelsea D. Boyd
- Department of Microbiology & Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire 03755, United States
| | - George A. O'Toole
- Department of Microbiology & Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire 03755, United States
| | - Yves F. Dufrêne
- Institute of Life Sciences, Université catholique de Louvain, Croix du Sud, 1, bte L7.04.01, B-1348 Louvain-la-Neuve, Belgium
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El-Kirat-Chatel S, Beaussart A, Boyd CD, O’Toole GA, Dufrêne YF. Single-cell and single-molecule analysis deciphers the localization, adhesion, and mechanics of the biofilm adhesin LapA. ACS Chem Biol 2014; 9:485-94. [PMID: 24556201 DOI: 10.1021/cb400794e] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The large adhesin protein LapA mediates adhesion and biofilm formation by Pseudomonas fluorescens. Although adhesion is thought to involve the long multiple repeats of LapA, very little is known about the molecular mechanism by which this protein mediates attachment. Here we use atomic force microscopy to unravel the biophysical properties driving LapA-mediated adhesion. Single-cell force spectroscopy shows that expression of LapA on the cell surface via biofilm-inducing conditions (i.e., phosphate-rich medium) or deletion of the gene encoding the LapG protease (LapA+ mutant) increases the adhesion strength of P. fluorescens toward hydrophobic and hydrophilic substrates, consistent with the adherent phenotypes observed in these conditions. Substrate chemistry plays an unexpected role in modulating the mechanical response of LapA, with sequential unfolding of the multiple repeats occurring only on hydrophilic substrates. Biofilm induction also leads to shortening of the protein extensions, reflecting stiffening of their conformational properties. Using single-molecule force spectroscopy, we next demonstrate that the adhesin is randomly distributed on the surface of wild-type cells and can be released into the solution. For LapA+ mutant cells, we found that the adhesin massively accumulates on the cell surface without being released and that individual LapA repeats unfold when subjected to force. The remarkable adhesive and mechanical properties of LapA provide a molecular basis for the "multi-purpose" adhesion function of LapA, thereby making P. fluorescens capable of colonizing diverse environments.
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Affiliation(s)
- Sofiane El-Kirat-Chatel
- Institute
of Life Sciences, Université catholique de Louvain, Croix du
Sud, 1, bte L7.04.01, B-1348 Louvain-la-Neuve, Belgium
| | - Audrey Beaussart
- Institute
of Life Sciences, Université catholique de Louvain, Croix du
Sud, 1, bte L7.04.01, B-1348 Louvain-la-Neuve, Belgium
| | - Chelsea D. Boyd
- Department of Microbiology & Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire 03755, United States
| | - George A. O’Toole
- Department of Microbiology & Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire 03755, United States
| | - Yves F. Dufrêne
- Institute
of Life Sciences, Université catholique de Louvain, Croix du
Sud, 1, bte L7.04.01, B-1348 Louvain-la-Neuve, Belgium
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Roles of cyclic Di-GMP and the Gac system in transcriptional control of the genes coding for the Pseudomonas putida adhesins LapA and LapF. J Bacteriol 2014; 196:1484-95. [PMID: 24488315 DOI: 10.1128/jb.01287-13] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
LapA and LapF are large extracellular proteins that play a relevant role in biofilm formation by Pseudomonas putida. Current evidence favors a sequential model in which LapA is first required for the initial adhesion of individual bacteria to a surface, while LapF participates in later stages of biofilm development. In agreement with this model, lapF transcription was previously shown to take place at late times of growth and to respond to the stationary-phase sigma factor RpoS. We have now analyzed the transcription pattern of lapA and other regulatory elements that influence expression of both genes. The lapA promoter shows a transient peak of activation early during growth, with a second increase in stationary phase that is independent of RpoS. The same pattern is observed in biofilms although expression is not uniform in the population. Both lapA and lapF are under the control of the two-component regulatory system GacS/GacA, and their transcription also responds to the intracellular levels of the second messenger cyclic diguanylate (c-di-GMP), although in surprisingly reverse ways. Whereas expression from the lapA promoter increases with high levels of c-di-GMP, the opposite is true for lapF. The transcriptional regulator FleQ is required for the modulation of lapA expression by c-di-GMP but has a minor influence on lapF. This work represents a further step in our understanding of the regulatory interactions controlling biofilm formation in P. putida.
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Castelhano Santos N, Pereira MO, Lourenço A. Pathogenicity phenomena in three model systems: from network mining to emerging system-level properties. Brief Bioinform 2013; 16:169-82. [PMID: 24106130 DOI: 10.1093/bib/bbt071] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Understanding the interconnections of microbial pathogenicity phenomena, such as biofilm formation, quorum sensing and antimicrobial resistance, is a tremendous open challenge for biomedical research. Progress made by wet-lab researchers and bioinformaticians in understanding the underlying regulatory phenomena has been significant, with converging evidence from multiple high-throughput technologies. Notably, network reconstructions are already of considerable size and quality, tackling both intracellular regulation and signal mediation in microbial infection. Therefore, it stands to reason that in silico investigations would play a more active part in this research. Drug target identification and drug repurposing could take much advantage of the ability to simulate pathogen regulatory systems, host-pathogen interactions and pathogen cross-talking. Here, we review the bioinformatics resources and tools available for the study of the gram-negative bacterium Pseudomonas aeruginosa, the gram-positive bacterium Staphylococcus aureus and the fungal species Candida albicans. The choice of these three microorganisms fits the rationale of the review converging into pathogens of great clinical importance, which thrive in biofilm consortia and manifest growing antimicrobial resistance.
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Draft Genome Sequence of Pseudomonas fluorescens LMG 5329, a White Line-Inducing Principle-Producing Bioindicator for the Mushroom Pathogen Pseudomonas tolaasii. GENOME ANNOUNCEMENTS 2013; 1:1/4/e00383-13. [PMID: 23887909 PMCID: PMC3735071 DOI: 10.1128/genomea.00383-13] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Pseudomonas tolaasii, the causative agent of Agaricus bisporus brown blotch disease, can be identified by the white line reaction, occurring upon confrontation of the tolaasin-producing mushroom pathogen with “Pseudomonas reactans,” producing the lipopeptide white line-inducing principle (WLIP). The draft genome sequence of the WLIP-producing indicator Pseudomonas fluorescens strain LMG 5329 is reported here.
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Fernández M, Conde S, Duque E, Ramos JL. In vivo gene expression of Pseudomonas putida KT2440 in the rhizosphere of different plants. Microb Biotechnol 2013; 6:307-13. [PMID: 23433036 PMCID: PMC3815925 DOI: 10.1111/1751-7915.12037] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Revised: 12/14/2012] [Accepted: 01/10/2013] [Indexed: 11/29/2022] Open
Abstract
Pseudomonas putida KT2440 has the ability to colonize the rhizosphere of a wide range of plants and can reach cell densities in the range of 105–106 cfu g soil−1. Using the IVET technology we investigated which KT2440 genes were expressed in the rhizosphere of four different plants: pine, cypress, evergreen oak and rosemary. We identified 39 different transcriptional fusions containing the promoters of annotated genes that were preferentially expressed in the rhizosphere. Six of them were expressed in the rhizosphere of all the plant types tested, 11 were expressed in more than one plant and the remaining 22 fusions were found to be expressed in only one type of plant. Another 40 fusions were found to correspond to likely promoters that encode antisense RNAs of unknown function, some of which were isolated as fusions from the bacteria recovered in the rhizosphere from all of the plants, while others were specific to one or several of the plants. The results obtained in this study suggest that plant-specific signals are sensed by KT2440 in the rhizosphere and that the signals and consequent gene expression are related to the bacteria's successful establishment in this niche.
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Affiliation(s)
- Matilde Fernández
- Bio-Iliberis Research and Development, I+D Department, 18210, Peligros, Granada, Spain
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Affiliation(s)
| | | | - Juan L. Ramos
- CSIC- Estacion Experimental del Zaidin; Granada; Spain
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