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Burns FN, Alila MA, Zheng H, Patil PD, Ibanez ACS, Luk YY. Exploration of Ligand-receptor Binding and Mechanisms for Alginate Reduction and Phenotype Reversion by Mucoid Pseudomonas aeruginosa. ChemMedChem 2021; 16:1975-1985. [PMID: 33666373 DOI: 10.1002/cmdc.202100121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Indexed: 11/09/2022]
Abstract
Bacteria in general can develop a wide range of phenotypes under different conditions and external stresses. The phenotypes that reside in biofilms, overproduce exopolymers, and show increased motility often exhibit drug tolerance and drug persistence. In this work, we describe a class of small molecules that delay and inhibit the overproduction of alginate by a non-swarming mucoid Pseudomonas aeruginosa. Among these molecules, selected benzophenone-derived alkyl disaccharides cause the mucoid bacteria to swarm on hydrated soft agar gel and revert the mucoid to a nonmucoid phenotype. The sessile (biofilm) and motile (swarming) phenotypes are controlled by opposing signaling pathways with high and low intracellular levels of bis-(3',5')-cyclic diguanosine monophosphate (cdG), respectively. As our molecules control several of these phenotypes, we explored a protein receptor, pilin of the pili appendages, that is consistent with controlling these bioactivities and signaling pathways. To test this binding hypothesis, we developed a bacterial motility-enabled binding assay that uses the interfacial properties of hydrated gels and bacterial motility to conduct label-free ligand-receptor binding studies. The structure-activity correlation and receptor identification reveal a plausible mechanism for reverting mucoid to nonmucoid phenotypes by binding pili appendages with ligands capable of sequestering and neutralizing reactive oxygen species.
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Affiliation(s)
- Felicia N Burns
- Department of Chemistry, Syracuse University, 1-014 CST, 111 College Place, Syracuse, NY, 13244, USA
| | - Mercy A Alila
- Department of Chemistry, Syracuse University, 1-014 CST, 111 College Place, Syracuse, NY, 13244, USA
| | - Hewen Zheng
- Department of Chemistry, Syracuse University, 1-014 CST, 111 College Place, Syracuse, NY, 13244, USA
| | - Pankaj D Patil
- Department of Chemistry, Syracuse University, 1-014 CST, 111 College Place, Syracuse, NY, 13244, USA
| | - Arizza Chiara S Ibanez
- Department of Chemistry, Syracuse University, 1-014 CST, 111 College Place, Syracuse, NY, 13244, USA
| | - Yan-Yeung Luk
- Department of Chemistry, Syracuse University, 1-014 CST, 111 College Place, Syracuse, NY, 13244, USA
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52
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Grekov I, Thöming JG, Kordes A, Häussler S. Evolution of Pseudomonas aeruginosa toward higher fitness under standard laboratory conditions. THE ISME JOURNAL 2021; 15:1165-1177. [PMID: 33273720 PMCID: PMC8115180 DOI: 10.1038/s41396-020-00841-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 11/04/2020] [Accepted: 11/11/2020] [Indexed: 01/29/2023]
Abstract
Identifying genetic factors that contribute to the evolution of adaptive phenotypes in pathogenic bacteria is key to understanding the establishment of infectious diseases. In this study, we performed mutation accumulation experiments to record the frequency of mutations and their effect on fitness in hypermutator strains of the environmental bacterium Pseudomonas aeruginosa in comparison to the host-niche-adapted Salmonella enterica. We demonstrate that P. aeruginosa, but not S. enterica, hypermutators evolve toward higher fitness under planktonic conditions. Adaptation to increased growth performance was accompanied by a reversible perturbing of the local genetic context of membrane and cell wall biosynthesis genes. Furthermore, we observed a fine-tuning of complex regulatory circuits involving multiple di-guanylate modulating enzymes that regulate the transition between fast growing planktonic and sessile biofilm-associated lifestyles. The redundancy and local specificity of the di-guanylate signaling pathways seem to allow a convergent shift toward increased growth performance across niche-adapted clonal P. aeruginosa lineages, which is accompanied by a pronounced heterogeneity of their motility, virulence, and biofilm phenotypes.
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Affiliation(s)
- Igor Grekov
- grid.7490.a0000 0001 2238 295XDepartment of Molecular Bacteriology, Helmholtz Centre for Infection Research, Braunschweig, Germany ,grid.475435.4Department of Clinical Microbiology, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark
| | - Janne Gesine Thöming
- grid.452370.70000 0004 0408 1805Institute of Molecular Bacteriology, TWINCORE Centre for Experimental and Clinical Infection Research, Hannover, Germany ,grid.475435.4Department of Clinical Microbiology, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark
| | - Adrian Kordes
- grid.452370.70000 0004 0408 1805Institute of Molecular Bacteriology, TWINCORE Centre for Experimental and Clinical Infection Research, Hannover, Germany ,grid.10423.340000 0000 9529 9877Cluster of Excellence RESIST (EXC 2155), Hannover Medical School, Hannover, Germany
| | - Susanne Häussler
- grid.7490.a0000 0001 2238 295XDepartment of Molecular Bacteriology, Helmholtz Centre for Infection Research, Braunschweig, Germany ,grid.452370.70000 0004 0408 1805Institute of Molecular Bacteriology, TWINCORE Centre for Experimental and Clinical Infection Research, Hannover, Germany ,grid.475435.4Department of Clinical Microbiology, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark ,grid.10423.340000 0000 9529 9877Cluster of Excellence RESIST (EXC 2155), Hannover Medical School, Hannover, Germany
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Qu J, Cai Z, Liu Y, Duan X, Han S, Liu J, Zhu Y, Jiang Z, Zhang Y, Zhuo C, Liu Y, Liu Y, Liu L, Yang L. Persistent Bacterial Coinfection of a COVID-19 Patient Caused by a Genetically Adapted Pseudomonas aeruginosa Chronic Colonizer. Front Cell Infect Microbiol 2021; 11:641920. [PMID: 33816347 PMCID: PMC8010185 DOI: 10.3389/fcimb.2021.641920] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 02/08/2021] [Indexed: 12/20/2022] Open
Abstract
Pseudomonas aeruginosa is a biofilm-forming opportunistic pathogen which causes chronic infections in immunocompromised patients and leads to high mortality rate. It is identified as a common coinfecting pathogen in COVID-19 patients causing exacerbation of illness. In our hospital, P. aeruginosa is one of the top coinfecting bacteria identified among COVID-19 patients. We collected a strong biofilm-forming P. aeruginosa strain displaying small colony variant morphology from a severe COVID-19 patient. Genomic and transcriptomic sequencing analyses were performed with phenotypic validation to investigate its adaptation in SARS-CoV-2 infected environment. Genomic characterization predicted specific genomic islands highly associated with virulence, transcriptional regulation, and DNA restriction-modification systems. Epigenetic analysis revealed a specific N6-methyl adenine (m6A) methylating pattern including methylation of alginate, flagellar and quorum sensing associated genes. Differential gene expression analysis indicated that this isolate formed excessive biofilm by reducing flagellar formation (7.4 to 1,624.1 folds) and overproducing extracellular matrix components including CdrA (4.4 folds), alginate (5.2 to 29.1 folds) and Pel (4.8–5.5 folds). In summary, we demonstrated that P. aeuginosa clinical isolates with novel epigenetic markers could form excessive biofilm, which might enhance its antibiotic resistance and in vivo colonization in COVID-19 patients.
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Affiliation(s)
- Jiuxin Qu
- Department of Clinical Laboratory, Shenzhen Third People's Hospital, Second Hospital Affiliated to Southern University of Science and Technology, National Clinical Research Center for Infectious Diseases, Shenzhen, China
| | - Zhao Cai
- School of Medicine, Southern University of Science and Technology, Shenzhen, China
| | - Yumei Liu
- School of Medicine, Southern University of Science and Technology, Shenzhen, China
| | - Xiangke Duan
- School of Medicine, Southern University of Science and Technology, Shenzhen, China
| | - Shuhong Han
- School of Medicine, Southern University of Science and Technology, Shenzhen, China
| | - Jihong Liu
- School of Medicine, Southern University of Science and Technology, Shenzhen, China.,Medical Research Center, Southern University of Science and Technology Hospital, Shenzhen, China
| | - Yuao Zhu
- School of Medicine, Southern University of Science and Technology, Shenzhen, China
| | - Zhaofang Jiang
- Department of Clinical Laboratory, Shenzhen Third People's Hospital, Second Hospital Affiliated to Southern University of Science and Technology, National Clinical Research Center for Infectious Diseases, Shenzhen, China
| | - Yingdan Zhang
- School of Medicine, Southern University of Science and Technology, Shenzhen, China
| | - Chao Zhuo
- The State Key Laboratory of Respiratory Diseases, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Yang Liu
- Medical Research Center, Southern University of Science and Technology Hospital, Shenzhen, China
| | - Yingxia Liu
- Department of Clinical Laboratory, Shenzhen Third People's Hospital, Second Hospital Affiliated to Southern University of Science and Technology, National Clinical Research Center for Infectious Diseases, Shenzhen, China.,Shenzhen Key Laboratory of Pathogen and Immunity, State Key Discipline of Infectious Disease, Shenzhen Third People's Hospital, Second Hospital Affiliated to Southern University of Science and Technology, Shenzhen, China
| | - Lei Liu
- Department of Clinical Laboratory, Shenzhen Third People's Hospital, Second Hospital Affiliated to Southern University of Science and Technology, National Clinical Research Center for Infectious Diseases, Shenzhen, China.,Shenzhen Key Laboratory of Pathogen and Immunity, State Key Discipline of Infectious Disease, Shenzhen Third People's Hospital, Second Hospital Affiliated to Southern University of Science and Technology, Shenzhen, China
| | - Liang Yang
- School of Medicine, Southern University of Science and Technology, Shenzhen, China.,Shenzhen Key Laboratory of Gene Regulation and Systems Biology, Southern University of Science and Technology, Shenzhen, China
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54
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Yamamoto K, Kusada H, Kamagata Y, Tamaki H. Parallel Evolution of Enhanced Biofilm Formation and Phage-Resistance in Pseudomonas aeruginosa during Adaptation Process in Spatially Heterogeneous Environments. Microorganisms 2021; 9:569. [PMID: 33801971 PMCID: PMC7999436 DOI: 10.3390/microorganisms9030569] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 02/22/2021] [Accepted: 03/06/2021] [Indexed: 11/16/2022] Open
Abstract
An opportunistic pathogen Pseudomonas aeruginosa has a versatile phenotype and high evolutionary potential to adapt to various natural habitats. As the organism normally lives in spatially heterogeneous and polymicrobial environments from open fields to the inside of hosts, adaptation to abiotic (spatial heterogeneity) and biotic factors (interspecies interactions) is a key process to proliferate. However, our knowledge about the adaptation process of P. aeruginosa in spatially heterogeneous environments associated with other species is limited. We show herein that the evolutionary dynamics of P. aeruginosa PAO1 in spatially heterogeneous environments with Staphylococcus aureus known to coexist in vivo is dictated by two distinct core evolutionary trajectories: (i) the increase of biofilm formation and (ii) the resistance to infection by a filamentous phage which is retained in the PAO1 genome. Hyperbiofilm and/or pili-deficient phage-resistant variants were frequently selected in the laboratory evolution experiment, indicating that these are key adaptive traits under spatially structured conditions. On the other hand, the presence of S. aureus had only a marginal effect on the emergence and maintenance of these variants. These results show key adaptive traits of P. aeruginosa and indicate the strong selection pressure conferred by spatial heterogeneity, which might overwhelm the effect of interspecies interactions.
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Affiliation(s)
- Kyosuke Yamamoto
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Sapporo 0628517, Hokkaido, Japan
- Bioproduction Research Institute, AIST, Tsukuba 3058566, Ibaraki, Japan; (H.K.); (Y.K.)
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba 3058577, Ibaraki, Japan
| | - Hiroyuki Kusada
- Bioproduction Research Institute, AIST, Tsukuba 3058566, Ibaraki, Japan; (H.K.); (Y.K.)
| | - Yoichi Kamagata
- Bioproduction Research Institute, AIST, Tsukuba 3058566, Ibaraki, Japan; (H.K.); (Y.K.)
| | - Hideyuki Tamaki
- Bioproduction Research Institute, AIST, Tsukuba 3058566, Ibaraki, Japan; (H.K.); (Y.K.)
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba 3058577, Ibaraki, Japan
- Biotechnology Research Center, University of Tokyo, Bunkyo-ku, Tokyo 1138657, Japan
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55
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Karanja CW, Yeboah KS, Sintim HO. Identification of a Mycobacterium tuberculosis Cyclic Dinucleotide Phosphodiesterase Inhibitor. ACS Infect Dis 2021; 7:309-317. [PMID: 33492938 DOI: 10.1021/acsinfecdis.0c00444] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Immune cells sense bacteria-derived c-di-GMP and c-di-AMP as well as host-derived cGAMP, which is synthesized by cGAS upon binding to the pathogen's DNA, to mount an immunological response (cytokine production) via the STING-TBK1 pathway. Successful pathogens, such as Mycobacterium tuberculosis and group B streptococcus, harbor phosphodiesterases (PDEs) that can cleave bacterial c-di-AMP as well as host-derived cGAMP to blunt the host's response to infection. Selective inhibitors of bacterial cyclic dinucleotide (CDN) PDEs are needed as tool compounds to study the role(s) of CDN PDEs during infection and they could also become bona fide antivirulence compounds, but there is a paucity of such compounds. Using a high-throughput assay, we identified six inhibitors of MTB CDN PDE (CdnP). The most potent inhibitor, C82 with an IC50 of ∼18 μM, did not inhibit the enzymatic activities of three other bacterial CDN PDEs (Yybt, RocR, and GBS-CdnP), a viral CDN PDE (poxin) or mammalian ENPP1.
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Affiliation(s)
- Caroline W. Karanja
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907-2084, United States
| | - Kofi S. Yeboah
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907-2084, United States
| | - Herman O. Sintim
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907-2084, United States
- Institute for Drug Discovery, Purdue University, 720 Clinic Drive, West Lafayette, Indiana 47907, United States
- Purdue Institute of Inflammation, Immunology, and Infectious Disease, Purdue University, 610 Purdue Mall, West Lafayette, Indiana 47907, United States
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56
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Pseudomonas aeruginosa Uses c-di-GMP Phosphodiesterases RmcA and MorA To Regulate Biofilm Maintenance. mBio 2021; 12:mBio.03384-20. [PMID: 33531388 PMCID: PMC7858071 DOI: 10.1128/mbio.03384-20] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Recent advances in our understanding of c-di-GMP signaling have provided key insights into the regulation of biofilms. Despite an improved understanding of how biofilms initially form, the processes that facilitate the long-term maintenance of these multicellular communities remain opaque. While the early stages of biofilm formation have been well characterized, less is known about the requirements for Pseudomonas aeruginosa to maintain a mature biofilm. We utilized a P. aeruginosa-phage interaction to identify rmcA and morA, two genes which encode bis-(3′,5′)-cyclic dimeric GMP (c-di-GMP)-degrading phosphodiesterases (PDEs) and are important for the regulation of biofilm maintenance. Deletion of these genes initially results in an elevated biofilm phenotype characterized by increased production of c-di-GMP, Pel polysaccharide, and/or biofilm biomass. In contrast to the wild-type strain, these mutants were unable to maintain the biofilm when exposed to carbon-limited conditions. The susceptibility to nutrient limitation, as well as subsequent loss of biofilm viability of these mutants, was phenotypically reproduced with a stringent response mutant (ΔrelA ΔspoT), indicating that the ΔrmcA and ΔmorA mutants may be unable to appropriately respond to nutrient limitation. Genetic and biochemical data indicate that RmcA and MorA physically interact with the Pel biosynthesis machinery, supporting a model whereby unregulated Pel biosynthesis contributes to the death of the ΔrmcA and ΔmorA mutant strains in an established biofilm under nutrient limitation. These findings provide evidence that c-di-GMP-mediated regulation is required for mature biofilms of P. aeruginosa to effectively respond to changing availability of nutrients. Furthermore, the PDEs involved in biofilm maintenance are distinct from those required for establishing a biofilm, suggesting that a wide variety of c-di-GMP metabolizing enzymes in organisms such as P. aeruginosa allows for discrete control over the formation, maintenance or dispersion of biofilms.
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57
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Armbruster CR, Parsek MR. Analysis of Pseudomonas aeruginosa c-di-GMP High and Low Subpopulations Using Flow-assisted Cell Sorting (FACS) and Quantitative Reverse Transcriptase PCR (qRT-PCR). Bio Protoc 2021; 11:e3891. [PMID: 33732780 DOI: 10.21769/bioprotoc.3891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 11/16/2020] [Accepted: 12/15/2020] [Indexed: 11/02/2022] Open
Abstract
Cyclic diguanylate monophosphate (c-di-GMP) is a second messenger signaling molecule that drives the transition from planktonic to the biofilm mode of growth in many bacterial species. Pseudomonas aeruginosa has at least two surface sensing systems that produce c-di-GMP in response to surface attachment, the Wsp and Pil-Chp systems. We recently used a plasmid-based c-di-GMP reporter (pP cdrA::gfp ) to describe how the Wsp system generates heterogeneity in surface sensing, resulting in two physiologically distinct subpopulations of cells during early biofilm formation. One subpopulation has elevated c-di-GMP and produces biofilm matrix, serving as the founders of initial microcolonies. The other subpopulation has low c-di-GMP and engages in surface motility, allowing for exploration of the surface. Here, we describe the protocol for a key experiment to confirm our initial observation of c-di-GMP heterogeneity during surface sensing: the use of flow-assisted cell sorting (FACS) to isolate subpopulations of cells with high and low c-di-GMP reporter activity, followed by quantitative Reverse Transcriptase PCR (qRT-PCR) of genes that are known to be transcriptionally regulated in response to cellular c-di-GMP levels (pelA, pslA). This protocol can be adapted by others to isolate subpopulations of high- and low- c-di-GMP P. aeruginosa cells that are genetically identical, but phenotypically distinct for future experiments examining specific mRNA transcripts as we did or, presumably, for additional applications like RNAseq, proteomics, or TNseq. Graphical abstract.
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Affiliation(s)
- Catherine R Armbruster
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA, USA
| | - Matthew R Parsek
- Department of Microbiology, University of Washington, Seattle, WA, USA
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58
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Jiao H, Li F, Wang T, Yam JKH, Yang L, Liang H. The Pyocin Regulator PrtR Regulates Virulence Expression of Pseudomonas aeruginosa by Modulation of Gac/Rsm System and c-di-GMP Signaling Pathway. Infect Immun 2021; 89:e00602-20. [PMID: 33168590 PMCID: PMC7822137 DOI: 10.1128/iai.00602-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 11/02/2020] [Indexed: 01/22/2023] Open
Abstract
In Pseudomonas aeruginosa, the second messenger cyclic-di-GMP and Gac/Rsm signaling pathways are associated with the transition from acute to chronic infection. Therefore, identification of the molecular mechanisms that govern lifestyle choice in bacteria is very important. Here, we identified a novel cyclic-di-GMP modulator, PrtR, which was shown to repress pyocin production by inhibition of PrtN and activate the type III secretion system (T3SS) through PtrB. Compared to a wild-type strain or a prtN mutant, the prtR prtN double mutant exhibited a wrinkly colony and hyperbiofilm phenotype, as well as an increase in intracellular c-di-GMP levels. Interestingly, a diguanylate cyclase (DGC) gene, siaD, was repressed by PrtR. Further experiments revealed that PrtR directly interacts with SiaD and facilitates the accumulation of c-di-GMP in cells. We also demonstrated that PrtR regulates the activity of the Gac/Rsm system, thus affecting expression of the T3SS and type VI secretion system (T6SS) and the formation of biofilm. Taken together, the present findings indicate that PrtR, as a c-di-GMP modulator, plays key roles in the adaptation to opportunistic infection of P. aeruginosa Additionally, this study revealed a novel mechanism for PrtR-mediated regulation of the lifestyle transition via the Gac/Rsm and c-di-GMP signaling networks.
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Affiliation(s)
- Hongying Jiao
- Key Laboratory of Resources Biology and Biotechnology in Western China, Ministry of Education, College of Life Sciences, Northwest University, Xi'an, ShaanXi, China
| | - Fan Li
- College of Animal Science and Technology, Northwest A&F University, Yangling, ShaanXi, China
| | - Tietao Wang
- Key Laboratory of Resources Biology and Biotechnology in Western China, Ministry of Education, College of Life Sciences, Northwest University, Xi'an, ShaanXi, China
| | - Joey Kuok Hoong Yam
- School of Biological Sciences, Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore
| | - Liang Yang
- School of Medicine, Southern University of Science and Technology, ShenZhen, China
| | - Haihua Liang
- Key Laboratory of Resources Biology and Biotechnology in Western China, Ministry of Education, College of Life Sciences, Northwest University, Xi'an, ShaanXi, China
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Firrao G, Scortichini M, Pagliari L. Orthology-Based Estimate of the Contribution of Horizontal Gene Transfer from Distantly Related Bacteria to the Intraspecific Diversity and Differentiation of Xylella fastidiosa. Pathogens 2021; 10:46. [PMID: 33430372 PMCID: PMC7828034 DOI: 10.3390/pathogens10010046] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 01/04/2021] [Accepted: 01/05/2021] [Indexed: 12/25/2022] Open
Abstract
Xylella fastidiosa is a xylem-limited bacterium phylogenetically related to the xanthomonads, with an unusually large and diversified range of plant hosts. To ascertain the origin of its peculiarities, its pan-genome was scanned to identify the genes that are not coherent with its phylogenetic position within the order Xanthomonadales. The results of the analysis revealed that a large fraction of the genes of the Xylella pan-genome have no ortholog or close paralog in the order Xanthomonadales. For a significant part of the genes, the closest homologue was found in bacteria belonging to distantly related taxonomic groups, most frequently in the Betaproteobacteria. Other species, such as Xanthomonas vasicola and Xanthomonas albilineans which were investigated for comparison, did not show a similar genetic contribution from distant branches of the prokaryotic tree of life. This finding indicates that the process of acquisition of DNA from the environment is still a relevant component of Xylella fastidiosa evolution. Although the ability of Xylella fastidiosa strains to recombine among themselves is well known, the results of the pan-genome analyses stressed the additional relevance of environmental DNA in shaping their genomes, with potential consequences on their phytopathological features.
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Affiliation(s)
- Giuseppe Firrao
- Dipartimento di Scienze Agroalimentari, Ambientali e Animali, University of Udine, Udine, Italy
- Istituto Nazionale Biostrutture e Biosistemi, Rome, Italy
| | - Marco Scortichini
- Consiglio per la Ricerca in Agricoltura e l’Analisi dell’Economia Agraria-Centro di ricerca per l’Olivicoltura, Frutticoltura e Agrumicoltura, Via di Fioranello, 52, 00134 Rome, Italy;
| | - Laura Pagliari
- Dipartimento di Scienze Agroalimentari, Ambientali e Animali, University of Udine, Udine, Italy
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60
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Dash SS, Samanta S, Dey S, Giri B, Dash SK. Rapid Green Synthesis of Biogenic Silver Nanoparticles Using Cinnamomum tamala Leaf Extract and its Potential Antimicrobial Application Against Clinically Isolated Multidrug-Resistant Bacterial Strains. Biol Trace Elem Res 2020; 198:681-696. [PMID: 32180127 DOI: 10.1007/s12011-020-02107-w] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 03/03/2020] [Indexed: 02/07/2023]
Abstract
Cinnamomum tamala is Indian bay leaves also known as Tej patta commonly used in the preparation of delicious food for its sweet aroma and tremendous medicinal values. In this study, the significant concentration-dependent free radical scavenging and antioxidant efficacy of the aqueous extracts of bay leaves has been determined using DPPH (2, 2-diphenyl-l-picrylhydrazyl) radical scavenging, ferric ion-reducing power assay, and hydrogen peroxide radical scavenging assay. The leaf extract has also been utilized in the rapid synthesis of silver nanoparticles (AgNPs) under mild conditions (30 min reaction time at 70 °C) without the addition of extra stabilizing or capping agents. Mostly spherical shaped particles were formed with diameter ranging from 10 to 12 nm as evident by HRTEM imaging. The silver nanoparticles were also characterized using FTIR, XRD, and UV-visible spectroscopic techniques. The antibacterial effect of the synthesized AgNPs was studied against three clinically isolated multidrug-resistant bacterial strains (Escherichia coli (EC-1), Klebsiella pneumonia (KP-1), and Staphylococcus aureus (SA-1)). The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of AgNPs against EC-1 were 12.5 and 15 μg/mL and in SA-1 were 10 and 50 μg/mL, and in the case of KP-1, both values were 12.5 μg/mL. It was also noted that 8 h treatment duration using AgNPs was sufficient to eliminate all types of bacterial growth as evidenced by time-dependent killing kinetic assays. The biocompatibilities of AgNPs were also tested against human health RBCs, and it was observed that it did not show any significant toxicity up to 50 μg/mL concentration.
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Affiliation(s)
- Shib Shankar Dash
- Department of Chemistry, Government General Degree College, Salboni , Paschim Medinipur, West Bengal, 721516, India.
| | - Sovan Samanta
- Department of Physiology, University of Gour Banga, Malda, West Bengal, 732103, India
| | - Sananda Dey
- Department of Physiology, University of Gour Banga, Malda, West Bengal, 732103, India
| | - Biplab Giri
- Department of Physiology, University of Gour Banga, Malda, West Bengal, 732103, India
| | - Sandeep Kumar Dash
- Department of Physiology, University of Gour Banga, Malda, West Bengal, 732103, India
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Abstract
Dickeya zeae is the etiological agent of bacterial foot rot disease, which can cause massive economic losses in banana and rice plantations. Genome sequence analysis showed that D. zeae strain EC1 contains multiple c-di-GMP turnover genes, but their roles and regulatory mechanisms in bacterial physiology and virulence remain vague. By generating consecutive in-frame deletion mutants of the genes encoding c-di-GMP biosynthesis and degradation, respectively, we analyzed the individual and collective impacts of these c-di-GMP metabolic genes on the c-di-GMP global pool, bacterial physiology, and virulence. The significance of our study is in identifying the mechanism of c-di-GMP signaling in strain EC1 more clearly, which expands the c-di-GMP regulating patterns in Gram-negative species. The methods and experimental designs in this research will provide a valuable reference for the exploration of the complex c-di-GMP regulation mechanisms in other bacteria. Dickeya zeae is an important and aggressive bacterial phytopathogen that can cause substantial economic losses in banana and rice plantations. We previously showed that c-di-GMP signaling proteins (cyclases/phosphodiesterases) in D. zeae strain EC1 play a significant role in the bacterial sessile-to-motile transition. To determine whether there is any synergistic effect among these c-di-GMP signaling proteins, we prepared a series of mutant strains by generating consecutive in-frame deletions of the genes encoding diguanylate cyclases (which make c-di-GMP) and phosphodiesterases (which break down c-di-GMP), respectively, using EC1 as a parental strain. The results showed that the complete deletion of all the putative diguanylate cyclases resulted in significantly increased bacterial motility and abrogated biofilm formation but did not appear to affect pathogenicity and virulence factor production. In contrast, the deletion of all the c-di-GMP phosphodiesterase genes disabled motility and prevented the invasion of EC1 into rice seeds. By measuring the c-di-GMP concentrations and swimming motility of all the mutants, we propose that c-di-GMP controlled swimming behavior through a multitiered program in a c-di-GMP concentration-dependent manner, which could be described as an L-shaped regression curve. These features are quite different from those that have been shown for other bacterial species such as Salmonella and Caulobacter crescentus. Further analysis identified three c-di-GMP signaling proteins, i.e., PDE10355, DGC14945, and PDE14950, that play dominant roles in influencing the global c-di-GMP pool of strain EC1. The findings from this study highlight the complexity and plasticity of c-di-GMP regulatory circuits in different bacterial species.
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Liang F, Zhang B, Yang Q, Zhang Y, Zheng D, Zhang LQ, Yan Q, Wu X. Cyclic-di-GMP Regulates the Quorum-Sensing System and Biocontrol Activity of Pseudomonas fluorescens 2P24 through the RsmA and RsmE Proteins. Appl Environ Microbiol 2020; 86:e02016-20. [PMID: 33036989 PMCID: PMC7688223 DOI: 10.1128/aem.02016-20] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 10/04/2020] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas fluorescens 2P24 is a rhizosphere bacterium that protects many crop plants against soilborne diseases caused by phytopathogens. The PcoI/PcoR quorum-sensing (QS) system and polyketide antibiotic 2,4-diacetylphloroglucinol (2,4-DAPG) are particularly relevant to the strain's biocontrol potential. In this study, we investigated the effects of c-di-GMP on the biocontrol activity of strain 2P24. The expression of the Escherichia coli diguanylate cyclase (YedQ) and phosphodiesterase (YhjH) in P. fluorescens 2P24 significantly increased and decreased the cellular concentration of c-di-GMP, respectively. The production of the QS signals N-acyl homoserine lactones (AHLs) and 2,4-DAPG was negatively regulated by c-di-GMP in 2P24. The regulatory proteins RsmA and RsmE were positively regulated by c-di-GMP. Genomic analysis revealed that 2P24 has 23 predicted proteins that contain c-di-GMP-synthesizing or -degrading domains. Among these proteins, C0J56_12915, C0J56_13325, and C0J56_27925 contributed to the production of c-di-GMP and were also involved in the regulation of the QS signal and antibiotic 2,4-DAPG production in P. fluorescens Overexpression of C0J56_12915, C0J56_13325, and C0J56_27925 in 2P24 impaired its root colonization and biocontrol activities. Taken together, these results demonstrated that c-di-GMP played an important role in fine-tuning the biocontrol traits of P. fluorescensIMPORTANCE In various bacteria, the bacterial second messenger c-di-GMP influences a wide range of cellular processes. However, the function of c-di-GMP on biocontrol traits in the plant-beneficial rhizobacteria remains largely unclear. The present work shows that the QS system and polyketide antibiotic 2,4-DAPG production are regulated by c-di-GMP through RsmA and RsmE proteins in P. fluorescens 2P24. The diguanylate cyclases (DGCs) C0J56_12915, C0J56_13325, and C0J56_27925 are especially involved in regulating the biocontrol traits of 2P24. Our work also demonstrated a connection between the Gac/Rsm cascade and the c-di-GMP signaling pathway in P. fluorescens.
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Affiliation(s)
- Fei Liang
- College of Agriculture, Guangxi University, Nanning, China
| | - Bo Zhang
- College of Agriculture, Guangxi University, Nanning, China
| | - Qingqing Yang
- College of Agriculture, Guangxi University, Nanning, China
| | - Yang Zhang
- College of Agriculture, Guangxi University, Nanning, China
| | - Dehong Zheng
- College of Agriculture, Guangxi University, Nanning, China
| | - Li-Qun Zhang
- College of Plant Protection, China Agricultural University, Beijing, China
| | - Qing Yan
- Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, Montana, USA
| | - Xiaogang Wu
- College of Agriculture, Guangxi University, Nanning, China
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63
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Ueda A, Ogasawara S, Horiuchi K. Identification of the genes controlling biofilm formation in the plant commensal Pseudomonas protegens Pf-5. Arch Microbiol 2020; 202:2453-2459. [PMID: 32607723 DOI: 10.1007/s00203-020-01966-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 06/20/2020] [Accepted: 06/24/2020] [Indexed: 12/20/2022]
Abstract
Determinant genes controlling biofilm formation in a plant commensal bacterium, Pseudomonas protegens Pf-5, were identified by transposon mutagenesis. Comprehensive screening of 7500 transposon-inserted mutants led to the isolation of four mutants exhibiting decreased and five mutants exhibiting increased biofilm formation. Mutations in the genes encoding MFS drug resistance transporter, LapA adhesive protein, RetS sensor histidine kinase/response regulator, and HecA adhesin/hemagglutinin led to decreased biofilm formation, indicating that these genes are necessary for biofilm formation in Pf-5. The mutants exhibiting increased biofilm formation had transposon insertions in the genes coding for an outer membrane protein, a GGDEF domain-containing protein, AraC transcriptional regulator, non-ribosomal peptide synthetase OfaB, and the intergenic region of a DNA-binding protein and the Aer aerotaxis receptor, suggesting that these genes are negative regulators of biofilm formation. Some of these mutants also showed altered swimming and swarming motilities, and a negative correlation between biofilm formation and swarming motility was observed. Thus, sessile-motile lifestyle is regulated by divergent regulatory genes in Pf-5.
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Affiliation(s)
- Akihiro Ueda
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, 739-8528, Japan.
- Graduate School of Biosphere Science, Hiroshima University, Higashi-Hiroshima, 739-8528, Japan.
| | - Shinta Ogasawara
- Graduate School of Biosphere Science, Hiroshima University, Higashi-Hiroshima, 739-8528, Japan
| | - Keishi Horiuchi
- School of Applied Biological Science, Hiroshima University, Higashi-Hiroshima, 739-8528, Japan
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64
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Huang T, Pu Q, Zhou C, Lin P, Gao P, Zhang X, Chu Y, Yue B, Wu M. MicroRNA-302/367 Cluster Impacts Host Antimicrobial Defense via Regulation of Mitophagic Response Against Pseudomonas aeruginosa Infection. Front Immunol 2020; 11:569173. [PMID: 33117356 PMCID: PMC7576609 DOI: 10.3389/fimmu.2020.569173] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 09/21/2020] [Indexed: 02/05/2023] Open
Abstract
Mitophagy has recently been implicated in bacterial infection but the underlying mechanism remains largely unknown. Here, we uncover a role of microRNA-302/367 cluster in regulating mitophagy and its associated host response against bacterial infection. We demonstrate that miR-302/367 cluster expression was significantly increased after Pseudomonas aeruginosa infection. Enhanced expression of miR-302/367 cluster accelerated the mitophagic response in macrophages, thus increasing clearance of invading P. aeruginosa by regulating production of reactive oxygen species (ROS), while application of miR-302/367 cluster inhibitors decreased bacterial clearance. Blocking mitophagy with siRNA against mitophagy receptor prohibitin 2 (PHB2) reduced the effect of miR-302/367 cluster on induction of mitophagy and its-associated P. aeruginosa elimination. In addition, we found that miR-302/367 cluster also increased bacterial clearance in mouse model. Mechanistically, we illustrate that miR-302/367 cluster binds to the 3′-untranslated region of nuclear factor kappa B (NF-κB), a negative regulator of mitophagy, accelerated the process of mitophagy by inhibiting NF-κB. Furthermore, inhibition of NF-κB in macrophages attenuated the ROS or cytokines production and may reduce cell injury by P. aeruginosa infection to maintain cellular homeostasis. Collectively, our findings elucidate that miR-302/367 cluster functions as potent regulators in mitophagy-mediated P. aeruginosa elimination and pinpoint an unexpected functional link between miRNAs and mitophagy.
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Affiliation(s)
- Ting Huang
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, Chengdu University, Chengdu, China.,Key Laboratory of Bio-resources and Eco-environment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu, China.,Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, United States
| | - Qinqin Pu
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, United States.,State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Chuanmin Zhou
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, United States
| | - Ping Lin
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, United States
| | - Pan Gao
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, United States.,State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Xiuyue Zhang
- Key Laboratory of Bio-resources and Eco-environment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu, China
| | - Yiwen Chu
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, Chengdu University, Chengdu, China
| | - Bisong Yue
- Key Laboratory of Bio-resources and Eco-environment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu, China
| | - Min Wu
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, United States
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65
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Xu K, Shen D, Han S, Chou SH, Qian G. A non-flagellated, predatory soil bacterium reprograms a chemosensory system to control antifungal antibiotic production via cyclic di-GMP signalling. Environ Microbiol 2020; 23:878-892. [PMID: 32779811 DOI: 10.1111/1462-2920.15191] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 07/31/2020] [Accepted: 08/08/2020] [Indexed: 11/29/2022]
Abstract
Lysobacter enzymogenes is a non-flagellated, soil proteobacterium that secretes a diffusible antibiotic known as heat-stable antifungal factor (HSAF) to kill nearby fungi for food. The genome of the model strain OH11 encodes a homologous Wsp system, which is generally deployed by flagellated bacteria to achieve flagella-dependent outputs via a c-di-GMP-FleQ complex, in which c-di-GMP is a ubiquitous dinucleotide second messenger and FleQ is a transcription factor (TF). Here, we show that the Wsp system in the non-flagellated OH11 participates in a unique c-di-GMP-dependent signalling pathway and forms a WspR-CdgL binary complex to alter HSAF production, in which WspR and CdgL act as a c-di-GMP diguanylate cyclase (DGC) and a non-TF binding protein respectively. We found that the phosphorylation of WspR activates its DGC activity and enhances c-di-GMP production while inhibiting HSAF biosynthesis. The phosphorylation of WspR also plays a key role in weakening WspR-CdgL binding and HSAF generation. Interestingly, c-di-GMP binding to CdgL did not seem to induce the disassociation of the WspR-CdgL complex. These observations, along with our earlier findings, lead us to propose a model in which L. enzymogenes re-programs the Wsp system via c-di-GMP signalling to regulate HSAF biosynthesis for the benefit of ecological adaptation.
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Affiliation(s)
- Kangwen Xu
- College of Plant Protection (Laboratory of Plant Immunity; Key Laboratory of Integrated Management of Crop Diseases and Pests), Nanjing Agricultural University, Nanjing, 210095, China
| | - Danyu Shen
- College of Plant Protection (Laboratory of Plant Immunity; Key Laboratory of Integrated Management of Crop Diseases and Pests), Nanjing Agricultural University, Nanjing, 210095, China
| | - Sen Han
- College of Plant Protection (Laboratory of Plant Immunity; Key Laboratory of Integrated Management of Crop Diseases and Pests), Nanjing Agricultural University, Nanjing, 210095, China
| | - Shan-Ho Chou
- Institute of Biochemistry, and NCHU Agricultural Biotechnology Centre, National Chung Hsing University, Taichung, Taiwan, ROC
| | - Guoliang Qian
- College of Plant Protection (Laboratory of Plant Immunity; Key Laboratory of Integrated Management of Crop Diseases and Pests), Nanjing Agricultural University, Nanjing, 210095, China
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66
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STING cyclic dinucleotide sensing originated in bacteria. Nature 2020; 586:429-433. [PMID: 32877915 PMCID: PMC7572726 DOI: 10.1038/s41586-020-2719-5] [Citation(s) in RCA: 221] [Impact Index Per Article: 55.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Accepted: 08/26/2020] [Indexed: 12/20/2022]
Abstract
Stimulator of interferon genes (STING) is a receptor in human cells that senses foreign cyclic dinucleotides that are released during bacterial infection and in endogenous cyclic GMP-AMP signalling during viral infection and anti-tumour immunity1-5. STING shares no structural homology with other known signalling proteins6-9, which has limited attempts at functional analysis and prevented explanation of the origin of cyclic dinucleotide signalling in mammalian innate immunity. Here we reveal functional STING homologues encoded within prokaryotic defence islands, as well as a conserved mechanism of signal activation. Crystal structures of bacterial STING define a minimal homodimeric scaffold that selectively responds to cyclic di-GMP synthesized by a neighbouring cGAS/DncV-like nucleotidyltransferase (CD-NTase) enzyme. Bacterial STING domains couple the recognition of cyclic dinucleotides with the formation of protein filaments to drive oligomerization of TIR effector domains and rapid NAD+ cleavage. We reconstruct the evolutionary events that followed the acquisition of STING into metazoan innate immunity, and determine the structure of a full-length TIR-STING fusion from the Pacific oyster Crassostrea gigas. Comparative structural analysis demonstrates how metazoan-specific additions to the core STING scaffold enabled a switch from direct effector function to regulation of antiviral transcription. Together, our results explain the mechanism of STING-dependent signalling and reveal the conservation of a functional cGAS-STING pathway in prokaryotic defence against bacteriophages.
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67
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Christensen DG, Marsden AE, Hodge-Hanson K, Essock-Burns T, Visick KL. LapG mediates biofilm dispersal in Vibrio fischeri by controlling maintenance of the VCBS-containing adhesin LapV. Mol Microbiol 2020; 114:742-761. [PMID: 32654271 DOI: 10.1111/mmi.14573] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 07/06/2020] [Accepted: 07/08/2020] [Indexed: 12/18/2022]
Abstract
Efficient symbiotic colonization of the squid Euprymna scolopes by the bacterium Vibrio fischeri depends on bacterial biofilm formation on the surface of the squid's light organ. Subsequently, the bacteria disperse from the biofilm via an unknown mechanism and enter through pores to reach the interior colonization sites. Here, we identify a homolog of Pseudomonas fluorescens LapG as a dispersal factor that promotes cleavage of a biofilm-promoting adhesin, LapV. Overproduction of LapG inhibited biofilm formation and, unlike the wild-type parent, a ΔlapG mutant formed biofilms in vitro. Although V. fischeri encodes two putative large adhesins, LapI (near lapG on chromosome II) and LapV (on chromosome I), only the latter contributed to biofilm formation. Consistent with the Pseudomonas Lap system model, our data support a role for the predicted c-di-GMP-binding protein LapD in inhibiting LapG-dependent dispersal. Furthermore, we identified a phosphodiesterase, PdeV, whose loss promotes biofilm formation similar to that of the ΔlapG mutant and dependent on both LapD and LapV. Finally, we found a minor defect for a ΔlapD mutant in initiating squid colonization, indicating a role for the Lap system in a relevant environmental niche. Together, these data reveal new factors and provide important insights into biofilm dispersal by V. fischeri.
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Affiliation(s)
- David G Christensen
- Department of Microbiology and Immunology, Loyola University Chicago, Maywood, IL, USA
| | - Anne E Marsden
- Department of Microbiology and Immunology, Loyola University Chicago, Maywood, IL, USA
| | - Kelsey Hodge-Hanson
- Department of Microbiology and Immunology, Loyola University Chicago, Maywood, IL, USA
| | - Tara Essock-Burns
- Kewalo Marine Laboratory, Pacific Biosciences Research Center, University of Hawai'i at Mānoa, Honolulu, HI, USA
| | - Karen L Visick
- Department of Microbiology and Immunology, Loyola University Chicago, Maywood, IL, USA
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68
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Collins AJ, Smith TJ, Sondermann H, O'Toole GA. From Input to Output: The Lap/c-di-GMP Biofilm Regulatory Circuit. Annu Rev Microbiol 2020; 74:607-631. [PMID: 32689917 DOI: 10.1146/annurev-micro-011520-094214] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Biofilms are the dominant bacterial lifestyle. The regulation of the formation and dispersal of bacterial biofilms has been the subject of study in many organisms. Over the last two decades, the mechanisms of Pseudomonas fluorescens biofilm formation and regulation have emerged as among the best understood of any bacterial biofilm system. Biofilm formation by P. fluorescens occurs through the localization of an adhesin, LapA, to the outer membrane via a variant of the classical type I secretion system. The decision between biofilm formation and dispersal is mediated by LapD, a c-di-GMP receptor, and LapG, a periplasmic protease, which together control whether LapA is retained or released from the cell surface. LapA localization is also controlled by a complex network of c-di-GMP-metabolizing enzymes. This review describes the current understanding of LapA-mediated biofilm formation by P. fluorescens and discusses several emerging models for the regulation and function of this adhesin.
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Affiliation(s)
- Alan J Collins
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.,Geisel School of Medicine at Dartmouth, Hanover, New Hampshire 03755, USA;
| | - T Jarrod Smith
- Geisel School of Medicine at Dartmouth, Hanover, New Hampshire 03755, USA; .,Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403, USA
| | | | - George A O'Toole
- Geisel School of Medicine at Dartmouth, Hanover, New Hampshire 03755, USA;
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69
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Abstract
During chronic lung infections, Pseudomonas aeruginosa grows in highly antibiotic-tolerant communities called biofilms that are difficult for the host to clear. We have developed models for studying P. aeruginosa biofilm dispersal in environments that replicate key features of the airway. We found that mechanisms of biofilm dispersal in these models may employ alternative or additional signaling mechanisms, highlighting the importance of the growth environment in dispersal events. We have adapted the models to accommodate apical fluid flow, bacterial clinical isolates, antibiotics, and primary human airway epithelial cells, all of which are relevant to understanding bacterial behaviors in the context of human disease. We also examined dispersal agents in combination with commonly used antipseudomonal antibiotics and saw improved clearance when nitrite was combined with the antibiotic aztreonam. Pseudomonas aeruginosa grows in highly antibiotic-tolerant biofilms during chronic airway infections. Dispersal of bacteria from biofilms may restore antibiotic susceptibility or improve host clearance. We describe models to study biofilm dispersal in the nutritionally complex environment of the human airway. P. aeruginosa was cocultured in the apical surface of airway epithelial cells (AECs) in a perfusion chamber. Dispersal, triggered by sodium nitrite, a nitric oxide (NO) donor, was tracked by live cell microscopy. Next, a static model was developed in which biofilms were grown on polarized AECs without flow. We observed that NO-triggered biofilm dispersal was an energy-dependent process. From the existing literature, NO-mediated biofilm dispersal is regulated by DipA, NbdA, RbdA, and MucR. Interestingly, altered signaling pathways appear to be used in this model, as deletion of these genes failed to block NO-induced biofilm dispersal. Similar results were observed using biofilms grown in an abiotic model on glass with iron-supplemented cell culture medium. In cystic fibrosis, airway mucus contributes to the growth environment, and a wide range of bacterial phenotypes are observed; therefore, we tested biofilm dispersal in a panel of late cystic fibrosis clinical isolates cocultured in the mucus overlying primary human AECs. Finally, we examined dispersal in combination with the clinically used antibiotics ciprofloxacin, aztreonam and tobramycin. In summary, we have validated models to study biofilm dispersal in environments that recapitulate key features of the airway and identified combinations of currently used antibiotics that may enhance the therapeutic effect of biofilm dispersal. IMPORTANCE During chronic lung infections, Pseudomonas aeruginosa grows in highly antibiotic-tolerant communities called biofilms that are difficult for the host to clear. We have developed models for studying P. aeruginosa biofilm dispersal in environments that replicate key features of the airway. We found that mechanisms of biofilm dispersal in these models may employ alternative or additional signaling mechanisms, highlighting the importance of the growth environment in dispersal events. We have adapted the models to accommodate apical fluid flow, bacterial clinical isolates, antibiotics, and primary human airway epithelial cells, all of which are relevant to understanding bacterial behaviors in the context of human disease. We also examined dispersal agents in combination with commonly used antipseudomonal antibiotics and saw improved clearance when nitrite was combined with the antibiotic aztreonam.
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70
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Gdaniec BG, Allard PM, Queiroz EF, Wolfender JL, van Delden C, Köhler T. Surface sensing triggers a broad-spectrum antimicrobial response in Pseudomonas aeruginosa. Environ Microbiol 2020; 22:3572-3587. [PMID: 32573899 PMCID: PMC7496599 DOI: 10.1111/1462-2920.15139] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 06/15/2020] [Accepted: 06/21/2020] [Indexed: 12/14/2022]
Abstract
Interspecies bacterial competition may occur via cell‐associated or secreted determinants and is key to successful niche colonization. We previously evolved Pseudomonas aeruginosa in the presence of Staphylococcus aureus and identified mutations in the Wsp surface‐sensing signalling system. Surprisingly, a ΔwspF mutant, characterized by increased c‐di‐GMP levels and biofilm formation capacity, showed potent killing activity towards S. aureus in its culture supernatant. Here, we used an unbiased metabolomic analysis of culture supernatants to identify rhamnolipids, alkyl quinoline N‐oxides and two siderophores as members of four chemical clusters, which were more abundant in the ΔwspF mutant supernatants. Killing activities were quorum‐sensing controlled but independent of c‐di‐GMP levels. Based on the metabolomic analysis, we formulated a synthetic cocktail of four compounds, showing broad‐spectrum anti‐bacterial killing, including both Gram‐positive and Gram‐negative bacteria. The combination of quorum‐sensing‐controlled killing and Wsp‐system mediated biofilm formation endows P. aeruginosa with capacities essential for niche establishment and host colonization.
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Affiliation(s)
- Bartosz Gerard Gdaniec
- Transplant Infectious Diseases Unit, University Hospital Geneva, Geneva, Switzerland.,Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Pierre-Marie Allard
- School of Pharmaceutical Sciences, EPGL, University of Geneva, University of Lausanne, Geneva, Switzerland
| | - Emerson Ferreira Queiroz
- School of Pharmaceutical Sciences, EPGL, University of Geneva, University of Lausanne, Geneva, Switzerland
| | - Jean-Luc Wolfender
- School of Pharmaceutical Sciences, EPGL, University of Geneva, University of Lausanne, Geneva, Switzerland
| | - Christian van Delden
- Transplant Infectious Diseases Unit, University Hospital Geneva, Geneva, Switzerland.,Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Thilo Köhler
- Transplant Infectious Diseases Unit, University Hospital Geneva, Geneva, Switzerland.,Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
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71
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Landry KS, Morey JM, Bharat B, Haney NM, Panesar SS. Biofilms-Impacts on Human Health and Its Relevance to Space Travel. Microorganisms 2020; 8:microorganisms8070998. [PMID: 32635371 PMCID: PMC7409192 DOI: 10.3390/microorganisms8070998] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 06/19/2020] [Accepted: 07/01/2020] [Indexed: 01/08/2023] Open
Abstract
As the world looks towards the stars, the impacts of endogenous and exogenous microorganisms on human health during long-duration space flight are subjects of increased interest within the space community. The presence and continued growth of bacterial biofilms about spacecraft has been documented for decades; however, the impact on crew health is in its infancy. The impacts of biofilms are well known in the medical, agricultural, commercial, and industrial spaces. It less known that biofilms are undermining many facets of space travel and that their effects need to be understood and addressed for future space missions. Biofilms can damage space crew health and spoil limited food supply. Yet, at the same time, they can benefit plant systems for food growth, nutrient development, and other biological systems that are being explored for use in space travel. Various biofilm removal techniques have been studied to mitigate the hazards posed by biofilm persistence during space travel. Because the presence of biofilms can advance or hinder humanity’s space exploration efforts, an understanding of their impacts over the duration of space flights is of paramount importance.
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Affiliation(s)
- Kyle S Landry
- Liberty Biosecurity, Expeditionary and Special Programs Division, Worcester, MA 01605, USA;
- Correspondence:
| | - Jose M Morey
- Liberty Biosecurity, Expeditionary and Special Programs Division, Worcester, MA 01605, USA;
| | - Bharat Bharat
- Department of Psychology, University of South Florida, St. Petersburg, FL 33620, USA;
| | - Nora M Haney
- Department of Urology, Johns Hopkins University, Baltimore, MD 21218, USA;
| | - Sandip S Panesar
- Department of Neurosurgery, Stanford University, Stanford, CA 94305, USA;
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72
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Intercepting second-messenger signaling by rationally designed peptides sequestering c-di-GMP. Proc Natl Acad Sci U S A 2020; 117:17211-17220. [PMID: 32611811 PMCID: PMC7382256 DOI: 10.1073/pnas.2001232117] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Cyclic diguanylate (c-di-GMP) regulates a wide range of bacterial cellular functions from biofilm formation to growth and survival. Based on the structural analysis of the complex of c-di-GMP with a bacterial effector protein followed by amino acid sequence optimization, we have developed a short peptide that binds c-di-GMP with nanomolar affinity and high specificity. This provides many opportunities for biotechnological and biomedical applications. In particular, we show that such an endogenously expressed peptide effectively reduces intracellular c-di-GMP and thereby inhibits and even disintegrates biofilms in Pseudomonas aeruginosa. The bacterial second messenger cyclic diguanylate (c-di-GMP) regulates a wide range of cellular functions from biofilm formation to growth and survival. Targeting a second-messenger network is challenging because the system involves a multitude of components with often overlapping functions. Here, we present a strategy to intercept c-di-GMP signaling pathways by directly targeting the second messenger. For this, we developed a c-di-GMP–sequestering peptide (CSP) that was derived from a CheY-like c-di-GMP effector protein. CSP binds c-di-GMP with submicromolar affinity. The elucidation of the CSP⋅c-di-GMP complex structure by NMR identified a linear c-di-GMP–binding motif, in which a self-intercalated c-di-GMP dimer is tightly bound by a network of H bonds and π-stacking interactions involving arginine and aromatic residues. Structure-based mutagenesis yielded a variant with considerably higher, low-nanomolar affinity, which subsequently was shortened to 19 residues with almost uncompromised affinity. We demonstrate that endogenously expressed CSP intercepts c-di-GMP signaling and effectively inhibits biofilm formation in Pseudomonas aeruginosa, the most widely used model for serious biofilm-associated medical implications.
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73
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Feng Q, Ahator SD, Zhou T, Liu Z, Lin Q, Liu Y, Huang J, Zhou J, Zhang LH. Regulation of Exopolysaccharide Production by ProE, a Cyclic-Di-GMP Phosphodiesterase in Pseudomonas aeruginosa PAO1. Front Microbiol 2020; 11:1226. [PMID: 32582123 PMCID: PMC7290235 DOI: 10.3389/fmicb.2020.01226] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Accepted: 05/14/2020] [Indexed: 11/13/2022] Open
Abstract
The ubiquitous second messenger c-di-GMP is involved in regulation of multiple biological functions including the important extracellular matrix exopolysaccharides (EPS). But how c-di-GMP metabolic proteins influence EPS and their enzymatic properties are not fully understood. Here we showed that deletion of proE, which encodes a protein with GGDEF-EAL hybrid domains, significantly increased the transcriptional expression of the genes encoding EPS production in Pseudomonas aeruginosa PAO1 and changed the bacterial colony morphology. Our data showed that ProE is a very active phosphodiesterase (PDE), with a high enzyme activity in degradation of c-di-GMP. Interestingly, the optimal activity of ProE was found in the presence of Co2+, unlike other PDEs that commonly rely on Mg2+ or Mn2+ for best performance. Furthermore, we identified three widely conserved novel residues that are critical for the function of ProE through site-directed mutagenesis. Subsequent study showed that ProE, together with other three key PDEs, i.e., RbdA, BifA, and DipA regulate the EPS production in P. aeruginosa PAO1. Moreover, by using the GFP-fusion approach, we observed that these four EPS associated-PDEs showed a polar localization pattern in general. Taken together, our data unveil the molecular mechanisms of ProE in regulation of EPS production, and provide a new insight on its enzymatic properties in degradation of c-di-GMP.
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Affiliation(s)
- Qishun Feng
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, China
| | - Stephen Dela Ahator
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, China
| | - Tian Zhou
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, China
| | - Zhiqing Liu
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, China
| | - Qiqi Lin
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, China
| | - Yang Liu
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, China
| | - Jiahui Huang
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, China
| | - Jianuan Zhou
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, China
| | - Lian-Hui Zhang
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, China
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74
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Valentini M, Filloux A. Multiple Roles of c-di-GMP Signaling in Bacterial Pathogenesis. Annu Rev Microbiol 2020; 73:387-406. [PMID: 31500536 DOI: 10.1146/annurev-micro-020518-115555] [Citation(s) in RCA: 89] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The intracellular signaling molecule cyclic di-GMP (c-di-GMP) regulates the lifestyle of bacteria and controls many key functions and mechanisms. In the case of bacterial pathogens, a wide variety of virulence lifestyle factors have been shown to be regulated by c-di-GMP. Evidence of the importance of this molecule for bacterial pathogenesis has become so great that new antimicrobial agents are tested for their capacity of targeting c-di-GMP signaling. This review summarizes the current knowledge on this topic and reveals its application for the development of new antivirulence intervention strategies.
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Affiliation(s)
- Martina Valentini
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, CH-1211 Geneva 4, Switzerland;
| | - Alain Filloux
- MRC Centre for Molecular Microbiology and Infection, Department of Life Sciences, Imperial College London, SW7 2AZ London, United Kingdom;
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75
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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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76
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Cho KH, Tryon RG, Kim JH. Screening for Diguanylate Cyclase (DGC) Inhibitors Mitigating Bacterial Biofilm Formation. Front Chem 2020. [DOI: 10.3389/fchem.2020.00264 [doi link]] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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77
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Cho KH, Tryon RG, Kim JH. Screening for Diguanylate Cyclase (DGC) Inhibitors Mitigating Bacterial Biofilm Formation. Front Chem 2020; 8:264. [PMID: 32373581 PMCID: PMC7186502 DOI: 10.3389/fchem.2020.00264] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Accepted: 03/18/2020] [Indexed: 01/08/2023] Open
Abstract
The majority of bacteria in the natural environment organize themselves into communal biofilms. Biofilm formation benefits bacteria conferring resistance to harmful molecules (e.g., antibiotics, disinfectants, and host immune factors) and coordinating their gene expression through quorum sensing (QS). A primary signaling molecule promoting bacterial biofilm formation is the universal second messenger cyclic di-GMP. This dinucleotide predominantly controls the gene expression of motility, adhesins, and capsule production to coordinate biofilm formation. Cyclic di-GMP is synthesized by diguanylate cyclases (DGCs) that have a GGDEF domain and is degraded by phosphodiesterases (PDEs) containing either an EAL or an HD-GYP domain. Since high cellular c-di-GMP concentrations are correlated with promoting the ability of bacteria to form biofilms, numerous research endeavors to identify chemicals capable of inhibiting the c-di-GMP synthesis activity of DGCs have been performed in order to inhibit bacterial biofilm formation. This review describes currently identified chemical inhibitors that disturb the activity of DGCs and the methods of screening and assay for their discovery.
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Affiliation(s)
- Kyu Hong Cho
- Department of Biology, Indiana State University, Terre Haute, IN, United States
| | - R Grant Tryon
- Department of Biology, Indiana State University, Terre Haute, IN, United States
| | - Jeong-Ho Kim
- Department of Biology and Chemistry, Liberty University, Lynchburg, VA, United States
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78
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Cai YM, Hutchin A, Craddock J, Walsh MA, Webb JS, Tews I. Differential impact on motility and biofilm dispersal of closely related phosphodiesterases in Pseudomonas aeruginosa. Sci Rep 2020; 10:6232. [PMID: 32277108 PMCID: PMC7148300 DOI: 10.1038/s41598-020-63008-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Accepted: 02/28/2020] [Indexed: 12/31/2022] Open
Abstract
In Pseudomonas aeruginosa, the transition between planktonic and biofilm lifestyles is modulated by the intracellular secondary messenger cyclic dimeric-GMP (c-di-GMP) in response to environmental conditions. Here, we used gene deletions to investigate how the environmental stimulus nitric oxide (NO) is linked to biofilm dispersal, focusing on biofilm dispersal phenotype from proteins containing putative c-di-GMP turnover and Per-Arnt-Sim (PAS) sensory domains. We document opposed physiological roles for the genes ΔrbdA and Δpa2072 that encode proteins with identical domain structure: while ΔrbdA showed elevated c-di-GMP levels, restricted motility and promoted biofilm formation, c-di-GMP levels were decreased in Δpa2072, and biofilm formation was inhibited, compared to wild type. A second pair of genes, ΔfimX and ΔdipA, were selected on the basis of predicted impaired c-di-GMP turnover function: ΔfimX showed increased, ΔdipA decreased NO induced biofilm dispersal, and the genes effected different types of motility, with reduced twitching for ΔfimX and reduced swimming for ΔdipA. For all four deletion mutants we find that NO-induced biomass reduction correlates with increased NO-driven swarming, underlining a significant role for this motility in biofilm dispersal. Hence P. aeruginosa is able to differentiate c-di-GMP output using structurally highly related proteins that can contain degenerate c-di-GMP turnover domains.
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Affiliation(s)
- Yu-Ming Cai
- National Biofilms Innovation Centre, University of Southampton, Southampton, SO17 1BJ, UK.,Biological Sciences, Institute for Life Sciences, University of Southampton, Southampton, SO17 1BJ, UK
| | - Andrew Hutchin
- Biological Sciences, Institute for Life Sciences, University of Southampton, Southampton, SO17 1BJ, UK.,Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, UK.,Structure and Function of Biological Membranes Lab, Université Libre de Bruxelles, Boulevard du Triomphe, 1050, Bruxelles, Belgium
| | - Jack Craddock
- National Biofilms Innovation Centre, University of Southampton, Southampton, SO17 1BJ, UK.,Biological Sciences, Institute for Life Sciences, University of Southampton, Southampton, SO17 1BJ, UK
| | - Martin A Walsh
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, UK.,Research Complex at Harwell, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0FA, UK
| | - Jeremy S Webb
- National Biofilms Innovation Centre, University of Southampton, Southampton, SO17 1BJ, UK.,Biological Sciences, Institute for Life Sciences, University of Southampton, Southampton, SO17 1BJ, UK
| | - Ivo Tews
- National Biofilms Innovation Centre, University of Southampton, Southampton, SO17 1BJ, UK. .,Biological Sciences, Institute for Life Sciences, University of Southampton, Southampton, SO17 1BJ, UK.
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79
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Froes TQ, Nicastro GG, de Oliveira Pereira T, de Oliveira Carneiro K, Alves Reis IM, Conceição RS, Branco A, Ifa DR, Baldini RL, Castilho MS. Calycopterin, a major flavonoid from Marcetia latifolia, modulates virulence-related traits in Pseudomonas aeruginosa. Microb Pathog 2020; 144:104142. [PMID: 32173496 DOI: 10.1016/j.micpath.2020.104142] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 01/31/2020] [Accepted: 03/10/2020] [Indexed: 01/30/2023]
Abstract
Although bacterial resistance is a worldwide growing concern, the development of bacteriostatic and bactericidal drugs has been decreasing in the last decade. Compounds that modulate the microorganism virulence, without killing it, have been considered promising alternatives to combat bacterial infections. However, most signaling pathways that regulate virulence are complex and not completely understood. The rich chemical diversity of natural products offers a good starting point to identify key compounds that shed some light on this matter. Therefore, we investigated the role of Marcetia latifolia ethanolic extract, as well as its major constituent, calycopterin (5,4'-dihydroxy-3,6,7,8-tetramethoxylflavone), in the regulation of virulence-related phenotypes of Pseudomonas aeruginosa. Our results show that calycopterin inhibits pyocyanin production (EC50 = 32 μM), reduces motility and increases biofilm formation in a dose-dependent manner. Such biological profile suggests that calycopterin modulates targets that may act upstream the quorum sensing regulators and points to its utility as a chemical probe to further investigate P. aeruginosa transition from planktonic to sessile lifestyle.
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Affiliation(s)
- Thamires Quadros Froes
- Programa de Pós-graduação Em Biotecnologia, Universidade Estadual de Feira de Santana, Bahia, Brazil
| | | | | | - Kelli de Oliveira Carneiro
- Departmento de Saúde, Laboratorio de Fotoquímica, Universidade Estadual de Feira de Santana, Bahia, Brazil
| | - Isabella Mary Alves Reis
- Departmento de Saúde, Laboratorio de Fotoquímica, Universidade Estadual de Feira de Santana, Bahia, Brazil
| | - Rodrigo Souza Conceição
- Departmento de Saúde, Laboratorio de Fotoquímica, Universidade Estadual de Feira de Santana, Bahia, Brazil
| | - Alexsandro Branco
- Departmento de Saúde, Laboratorio de Fotoquímica, Universidade Estadual de Feira de Santana, Bahia, Brazil
| | - Demian Rocha Ifa
- Centre for Research in Mass Spectrometry, Department of Chemistry, York University, Toronto, ON, Canada
| | - Regina Lúcia Baldini
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Marcelo Santos Castilho
- Programa de Pós-graduação Em Biotecnologia, Universidade Estadual de Feira de Santana, Bahia, Brazil; Faculdade de Farmácia, Universidade Federal da Bahia, Bahia, Brazil.
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80
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Chen G, Gan J, Yang C, Zuo Y, Peng J, Li M, Huo W, Xie Y, Zhang Y, Wang T, Deng X, Liang H. The SiaA/B/C/D signaling network regulates biofilm formation in Pseudomonas aeruginosa. EMBO J 2020; 39:e103412. [PMID: 32090355 DOI: 10.15252/embj.2019103412] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Revised: 01/21/2020] [Accepted: 02/03/2020] [Indexed: 11/09/2022] Open
Abstract
Bacterial cyclic-di-GMP (c-di-GMP) production is associated with biofilm development and the switch from acute to chronic infections. In Pseudomonas aeruginosa, the diguanylate cyclase (DGC) SiaD and phosphatase SiaA, which are co-transcribed as part of a siaABCD operon, are essential for cellular aggregation. However, the detailed functions of this operon and the relationships among its constituent genes are unknown. Here, we demonstrate that the siaABCD operon encodes for a signaling network that regulates SiaD enzymatic activity to control biofilm and aggregates formation. Through protein-protein interaction, SiaC promotes SiaD diguanylate cyclase activity. Biochemical and structural data revealed that SiaB is an unusual protein kinase that phosphorylates SiaC, whereas SiaA phosphatase can dephosphorylate SiaC. The phosphorylation state of SiaC is critical for its interaction with SiaD, which will switch on or off the DGC activity of SiaD and regulate c-di-GMP levels and subsequent virulence phenotypes. Collectively, our data provide insights into the molecular mechanisms underlying the modulation of DGC activity associated with chronic infections, which may facilitate the development of antimicrobial drugs.
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Affiliation(s)
- Gukui Chen
- Key Laboratory of Resources Biology and Biotechnology in Western China, Ministry of Education, College of Life Sciences, Northwest University, Xi'an, Shaanxi, China
| | - Jianhua Gan
- State Key Laboratory of Genetic Engineering, Shanghai Public Health Clinical Center, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China
| | - Chun Yang
- State Key Laboratory of Genetic Engineering, Shanghai Public Health Clinical Center, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China
| | - Yili Zuo
- Key Laboratory of Resources Biology and Biotechnology in Western China, Ministry of Education, College of Life Sciences, Northwest University, Xi'an, Shaanxi, China
| | - Juan Peng
- Key Laboratory of Resources Biology and Biotechnology in Western China, Ministry of Education, College of Life Sciences, Northwest University, Xi'an, Shaanxi, China
| | - Meng Li
- Key Laboratory of Resources Biology and Biotechnology in Western China, Ministry of Education, College of Life Sciences, Northwest University, Xi'an, Shaanxi, China
| | - Weiping Huo
- Key Laboratory of Resources Biology and Biotechnology in Western China, Ministry of Education, College of Life Sciences, Northwest University, Xi'an, Shaanxi, China
| | - Yingpeng Xie
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong, China
| | - Yani Zhang
- Key Laboratory of Resources Biology and Biotechnology in Western China, Ministry of Education, College of Life Sciences, Northwest University, Xi'an, Shaanxi, China
| | - Tietao Wang
- Key Laboratory of Resources Biology and Biotechnology in Western China, Ministry of Education, College of Life Sciences, Northwest University, Xi'an, Shaanxi, China
| | - Xin Deng
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong, China
| | - Haihua Liang
- Key Laboratory of Resources Biology and Biotechnology in Western China, Ministry of Education, College of Life Sciences, Northwest University, Xi'an, Shaanxi, China
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81
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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] [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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82
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Bhasme P, Wei Q, Xu A, Naqvi STA, Wang D, Ma LZ. Evaluation and characterization of the predicted diguanylate cyclase-encoding genes in Pseudomonas aeruginosa. Microbiologyopen 2020; 9:e975. [PMID: 32012489 PMCID: PMC7066473 DOI: 10.1002/mbo3.975] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 11/07/2019] [Accepted: 11/11/2019] [Indexed: 02/06/2023] Open
Abstract
Opportunistic pathogen Pseudomonas aeruginosa can cause acute and chronic infections in humans. It is notorious for its resistance to antibiotics due to the formation of biofilms. Cyclic‐di‐GMP is a bacterial second messenger that plays important roles during biofilm development. There are 40 genes in P. aeruginosa predicted to participate in c‐di‐GMP biosynthesis or degradation. It is time‐consuming for the functional characterization of these genes. Here, we cloned 16 genes from P. aeruginosa PAO1 that are predicted to encode diguanylate cyclases (DGCs, responsible for c‐di‐GMP biosynthesis) and constructed their corresponding in‐frame deletion mutants. We evaluated the methods to measure the intracellular c‐di‐GMP concentration by using deletion mutants and PAO1 strains containing a plasmid expressing one of the 16 genes, respectively. Functional outputs of all PAO1‐derived stains were also detected and evaluated, including biofilm formation, production of exopolysaccharide, swimming and swarming motilities. Our data showed that measuring the c‐di‐GMP level only characterized a few DGC by using either pCdrA::gfp as a reporter or LC/MS/MS. Functional output results indicated that overexpression of a DGC gave more pronounced phenotypes than the corresponding deletion mutant and suggested that the swimming motility assay could be a quick way to briefly estimate a predicted DGC for further studies. The overall evaluation suggested 15 out of 16 predicted DGCs were functional DGCs, wherein six were characterized to encode DGCs previously. Altogether, we have provided not only a cloning library of 16 DGC‐encoding genes and their corresponding in‐frame deletion mutants but also paved ways to briefly characterize a predicted DGC.
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Affiliation(s)
- Pramod Bhasme
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Qing Wei
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Anming Xu
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Syed Tatheer Alam Naqvi
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Di Wang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Luyan Z Ma
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
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83
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Nie H, Xiao Y, He J, Liu H, Nie L, Chen W, Huang Q. Phenotypic-genotypic analysis of GGDEF/EAL/HD-GYP domain-encoding genes in Pseudomonas putida. ENVIRONMENTAL MICROBIOLOGY REPORTS 2020; 12:38-48. [PMID: 31691501 DOI: 10.1111/1758-2229.12808] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 11/03/2019] [Indexed: 06/10/2023]
Abstract
Cyclic diguanylate (c-di-GMP) is a broadly conserved bacterial signalling molecule that modulates diverse cellular processes, such as biofilm formation, colony morphology and swimming motility. The intracellular level of c-di-GMP is controlled by diguanylate cyclases (DGCs) with GGDEF domain and phosphodiesterases (PDEs) with either EAL or HD-GYP domain. Pseudomonas putida KT2440 has a large group of genes on its genome encoding proteins with GGDEF/EAL/HD-GYP domains. However, phenotypic-genotypic correlation and c-di-GMP metabolism of these genes were largely unknown. Herein, by systematically constructing deletion mutants/overexpression strains of the 42 predicted c-di-GMP metabolism-related genes and analysing the phenotypes, we preliminarily revealed the role of each gene in biofilm formation, colony morphology and swimming motility. Subsequent results from protein sequence alignments and cellular c-di-GMP assessment indicated that 25 out of the 42 genes were likely to encode DGCs, nine genes were predicted to encode PDEs, four genes encoded bifunctional enzymes and the other four genes encoded enzymatically inactive proteins. This study offers a basic understanding of the roles of these 42 genes and can serve as a toolkit for investigators to further elucidate the functions of these GGDEF and EAL/HD-GYP domain-containing proteins.
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Affiliation(s)
- Hailing Nie
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Yujie Xiao
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Jinzhi He
- 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
| | - Liang Nie
- State Key Laboratory of Agricultural Microbiology, 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
- Hubei Key Laboratory of Soil Environment and Pollution Remediation, College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China
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84
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Wang F, Wang Y, Cen C, Fu L, Wang Y. A tandem GGDEF-EAL domain protein-regulated c-di-GMP signal contributes to spoilage-related activities of Shewanella baltica OS155. Appl Microbiol Biotechnol 2020; 104:2205-2216. [PMID: 31927761 DOI: 10.1007/s00253-020-10357-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 12/23/2019] [Accepted: 01/05/2020] [Indexed: 11/26/2022]
Abstract
Cyclic diguanylate (c-di-GMP) is a second messenger involved in the regulation of various physiological processes in bacteria. However, its function in spoilage bacteria has not yet been addressed. Here, we studied the function of a tandem GGDEF-EAL domain protein, Sbal_3235, in the spoilage bacterium Shewanella baltica OS155. The deletion of sbal_3235 significantly reduced the c-di-GMP level, biofilm formation, and exopolysaccharide, trimethylamine (TMA), and putrescine production; sbal_3235 deletion also downregulated the expression of the torS and speF genes and affected membrane fatty acid composition. Site-directed mutagenesis in conserved GGDEF and EAL motifs abolished diguanylate cyclase (DGC) and phosphodiesterase (PDE) activity, respectively. These data indicate that Sbal_3235 is an essential contributor to the c-di-GMP pool with bifunctional DGC and PDE activity, which is involved in the biofilm formation and spoilage activity of S. baltica OS155. Our findings expand the biochemical role of c-di-GMP and uncover its link to spoilage activities, providing novel targets for food quality and safety controlling.
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Affiliation(s)
- Feifei Wang
- Food Safety Key Laboratory of Zhejiang Province, School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, 310018, People's Republic of China
| | - Yongzheng Wang
- Food Safety Key Laboratory of Zhejiang Province, School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, 310018, People's Republic of China
| | - Congnan Cen
- Food Safety Key Laboratory of Zhejiang Province, School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, 310018, People's Republic of China
| | - Linglin Fu
- Food Safety Key Laboratory of Zhejiang Province, School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, 310018, People's Republic of China.
- Zhejiang Engineering Institute of Food Quality and Safety, Zhejiang Gongshang University, Hangzhou, 310018, People's Republic of China.
| | - Yanbo Wang
- Food Safety Key Laboratory of Zhejiang Province, School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, 310018, People's Republic of China.
- Zhejiang Engineering Institute of Food Quality and Safety, Zhejiang Gongshang University, Hangzhou, 310018, People's Republic of China.
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85
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Castelletto V, Edwards-Gayle CJC, Hamley IW, Barrett G, Seitsonen J, Ruokolainen J, de Mello LR, da Silva ER. Model self-assembling arginine-based tripeptides show selective activity against Pseudomonas bacteria. Chem Commun (Camb) 2020; 56:615-618. [DOI: 10.1039/c9cc07257h] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Three model arginine-rich tripeptides RXR (X = W, F or non-natural residue 2-napthylalanine) were investigated as antimicrobial agents, with a specific focus to target Pseudomonas aeruginosa through membrane lysis.
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Affiliation(s)
| | | | - Ian W. Hamley
- Department of Chemistry
- University of Reading
- Reading RG6 6AD
- UK
| | - Glyn Barrett
- School of Biological Sciences
- University of Reading
- Reading RG6 6UR
- UK
| | - Jani Seitsonen
- Nanomicroscopy Center
- Aalto University
- FIN-02150 Espoo
- Finland
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86
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Jia X, Zhang S, Li J, Xia J, Yao R, Zhao X, Wu B, Bai F, Xiao Y. Engineered bacterial biofloc formation enhancing phenol removal and cell tolerance. Appl Microbiol Biotechnol 2019; 104:1187-1199. [PMID: 31834438 DOI: 10.1007/s00253-019-10289-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Revised: 11/18/2019] [Accepted: 11/28/2019] [Indexed: 12/17/2022]
Abstract
A microbial floc consisting of a community of microbes embedded in extracellular polymeric substances matrix can provide microbial resistances to toxic chemicals and harsh environments. Phenol is a toxic environmental pollutant and a typical lignin-derived phenolic inhibitor. In this study, we genetically engineered Escherichia coli cells by expressions of diguanylate cyclases (DGCs) to promote proteinaceous and aliphatic biofloc formation. Compared with the planktonic E. coli cells, the biofloc-forming cells improved phenol removal rate by up to 2.2-folds, due to their substantially improved tolerance (up to 149%) to phenol and slightly enhanced cellular activity (20%) of phenol hydroxylase (PheH). The engineered bioflocs also improved E. coli tolerance to other toxic compounds such as furfural, 5-hydroxymethylfurfural, and guaiacol. Additionally, the strategy of the engineered biofloc formation was applicable to Pseudomonas putida and enhanced its tolerance to phenol. This study highlights a strategy to form engineered bioflocs for improved cell tolerance and removal of toxic compounds, enabling their universality of use in bioproduction and bioremediation.
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Affiliation(s)
- Xiao Jia
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Shun Zhang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Jiawei Li
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Juan Xia
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Ruilian Yao
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Xinqing Zhao
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Bing Wu
- Faculty of Civil and Environmental Engineering, University of Iceland, Hjardarhagi 2-6, IS-107, Reykjavik, Iceland
| | - Fengwu Bai
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Yi Xiao
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.
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87
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Luo G, Zhao L, Xu X, Qin Y, Huang L, Su Y, Zheng W, Yan Q. Integrated dual RNA-seq and dual iTRAQ of infected tissue reveals the functions of a diguanylate cyclase gene of Pseudomonas plecoglossicida in host-pathogen interactions with Epinephelus coioides. FISH & SHELLFISH IMMUNOLOGY 2019; 95:481-490. [PMID: 31698069 DOI: 10.1016/j.fsi.2019.11.008] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2019] [Revised: 10/30/2019] [Accepted: 11/02/2019] [Indexed: 06/10/2023]
Abstract
The interactions between host and pathogen is exceedingly complex, which involves alterations at multiple molecular layers. However, research to simultaneously monitor the alterations of transcriptome and proteome between a bacterial pathogen and aquatic animal host through integrated dual RNA-seq and dual iTRAQ of tissue during infection is currently lacking. The important role of a diguanylate cyclase gene (L321_RS15240) in pathogenicity of Pseudomonas plecoglossicida against Epinephelus coioides was suggested by previous dual RNA-seq of our lab. Then L321_RS15240-RNAi strains of P. plecoglossicida were constructed with pCM130/tac, and the mutant with the best silencing effect was selected for follow-up study. The RNAi of L321_RS15240 resulted in a significant decrease in bacterial virulence of P. plecoglossicida. The E. coioides spleens infected by wild type strain or L321_RS15240-RNAi strain of P. plecoglossicida were subjected to dual RNA-seq and dual iTRAQ, respectively. The results showed that: RNAi of L321_RS15240 led to 1)alterations of host transcriptome associated with complement and coagulation cascades, ribosome, arginine and proline metabolism, and oxidative phosphorylation; 2)high expression of host proteins which related to phagosome and metabolism responses (metabolism of glutathione, amino sugar and nucleotide sugar); 3)the highly differentially expression of host lncRNAs and miRNAs. The differentially expressed proteins and mRNAs of pathogen were different after infection, but the functions of these proteins and mRNAs were mainly related to metabolism and virulence. This study provides a new insight to comprehensively understand the gene functions of pathogens and hosts at multiple molecular layers during in vivo infection.
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Affiliation(s)
- Gang Luo
- Fisheries College, Jimei University, Xiamen, Fujian, 361021, PR China; Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, Hubei, 430072, PR China
| | - Lingmin Zhao
- Fisheries College, Jimei University, Xiamen, Fujian, 361021, PR China
| | - Xiaojin Xu
- Fisheries College, Jimei University, Xiamen, Fujian, 361021, PR China
| | - Yingxue Qin
- Fisheries College, Jimei University, Xiamen, Fujian, 361021, PR China
| | - Lixing Huang
- Fisheries College, Jimei University, Xiamen, Fujian, 361021, PR China
| | - Yongquan Su
- State Key Laboratory of Large Yellow Croaker Breeding, Ningde, Fujian, 352000, PR China
| | - Weiqiang Zheng
- State Key Laboratory of Large Yellow Croaker Breeding, Ningde, Fujian, 352000, PR China
| | - Qingpi Yan
- Fisheries College, Jimei University, Xiamen, Fujian, 361021, PR China; State Key Laboratory of Large Yellow Croaker Breeding, Ningde, Fujian, 352000, PR China.
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88
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Qvortrup K, Hultqvist LD, Nilsson M, Jakobsen TH, Jansen CU, Uhd J, Andersen JB, Nielsen TE, Givskov M, Tolker-Nielsen T. Small Molecule Anti-biofilm Agents Developed on the Basis of Mechanistic Understanding of Biofilm Formation. Front Chem 2019; 7:742. [PMID: 31737611 PMCID: PMC6838868 DOI: 10.3389/fchem.2019.00742] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 10/17/2019] [Indexed: 01/12/2023] Open
Abstract
Microbial biofilms are the cause of persistent infections associated with various medical implants and distinct body sites such as the urinary tract, lungs, and wounds. Compared with their free living counterparts, bacteria in biofilms display a highly increased resistance to immune system activities and antibiotic treatment. Therefore, biofilm infections are difficult or impossible to treat with our current armory of antibiotics. The challenges associated with biofilm infections have urged researchers to pursue a better understanding of the molecular mechanisms that are involved in the formation and dispersal of biofilms, and this has led to the identification of several steps that could be targeted in order to eradicate these challenging infections. Here we describe mechanisms that are involved in the regulation of biofilm development in Pseudomonas aeruginosa, Escherichia coli, and Acinetobacter baumannii, and provide examples of chemical compounds that have been developed to specifically inhibit these processes. These compounds include (i) pilicides and curlicides which inhibit the initial steps of biofilm formation by E. coli; (ii) compounds that interfere with c-di-GMP signaling in P. aeruginosa and E. coli; and (iii) compounds that inhibit quorum-sensing in P. aeruginosa and A. baumannii. In cases where compound series have a defined molecular target, we focus on elucidating structure activity relationship (SAR) trends within the particular compound series.
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Affiliation(s)
- Katrine Qvortrup
- Department of Chemistry, Technical University of Denmark, Lyngby, Denmark
| | - Louise Dahl Hultqvist
- Department of Immunology and Microbiology, Costerton Biofilm Center, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Martin Nilsson
- Department of Immunology and Microbiology, Costerton Biofilm Center, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Tim Holm Jakobsen
- Department of Immunology and Microbiology, Costerton Biofilm Center, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Jesper Uhd
- Department of Chemistry, Technical University of Denmark, Lyngby, Denmark
| | - Jens Bo Andersen
- Department of Immunology and Microbiology, Costerton Biofilm Center, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Thomas E Nielsen
- Department of Immunology and Microbiology, Costerton Biofilm Center, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Michael Givskov
- Department of Immunology and Microbiology, Costerton Biofilm Center, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Tim Tolker-Nielsen
- Department of Immunology and Microbiology, Costerton Biofilm Center, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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89
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Diguanylate Cyclases and Phosphodiesterases Required for Basal-Level c-di-GMP in Pseudomonas aeruginosa as Revealed by Systematic Phylogenetic and Transcriptomic Analyses. Appl Environ Microbiol 2019; 85:AEM.01194-19. [PMID: 31444209 DOI: 10.1128/aem.01194-19] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 08/19/2019] [Indexed: 11/20/2022] Open
Abstract
Cyclic diguanosine monophosphate (c-di-GMP) is an important second messenger involved in bacterial switching from motile to sessile lifestyles. In the opportunistic pathogen Pseudomonas aeruginosa, at least 40 genes are predicted to encode proteins for the making and breaking of this signal molecule. However, there is still paucity of information concerning the systemic expression pattern of these genes and the functions of uncharacterized genes. In this study, we analyzed the phylogenetic distribution of genes from P. aeruginosa that were predicted to have a GGDEF domain and found five genes (PA5487, PA0285, PA0290, PA4367, and PA5017) with highly conserved distribution across 52 public complete pseudomonad genomes. PA5487 was further characterized as a typical diguanylate cyclase (DGC) and was named dgcH A systemic analysis of the gene expression data revealed that the expression of dgcH is highly invariable and that dgcH probably functions as a conserved gene to maintain the basal level of c-di-GMP, as reinforced by gene expression analyses. The other four conserved genes also had an expression pattern similar to that of dgcH The functional analysis suggested that PA0290 encoded a DGC, while the others functioned as phosphodiesterases (PDEs). Our data revealed that there are five DGC and PDE genes that maintain the basal level of c-di-GMP in P. aeruginosa IMPORTANCE Pseudomonas aeruginosa is an opportunistic pathogen that can cause infections in animals, humans, and plants. The formation of biofilms by P. aeruginosa is the central mode of action to persist in hosts and evade immune and antibiotic attacks. Cyclic-di-GMP (c-di-GMP) is an important second messenger involved in the regulation of biofilm formation. In P. aeruginosa PAO1 strain, there are around 40 genes that encode enzymes for making and breaking this dinucleotide. A major missing piece of information in this field is the phylogeny and expression profile of those genes. Here, we took a systemic approach to investigate this mystery. We found that among 40 c-di-GMP metabolizing genes, 5 have well-conserved phylogenetic distribution and invariable expression profiles, suggesting that there are enzymes required for the basal level of c-di-GMP in P. aeruginosa This study thus provides putative therapeutic targets against P. aeruginosa infections.
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90
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Engin AB, Engin A. Nanoantibiotics: A Novel Rational Approach to Antibiotic Resistant Infections. Curr Drug Metab 2019; 20:720-741. [DOI: 10.2174/1389200220666190806142835] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 07/19/2019] [Accepted: 07/19/2019] [Indexed: 01/09/2023]
Abstract
Background:The main drawbacks for using conventional antimicrobial agents are the development of multiple drug resistance due to the use of high concentrations of antibiotics for extended periods. This vicious cycle often generates complications of persistent infections, and intolerable antibiotic toxicity. The problem is that while all new discovered antimicrobials are effective and promising, they remain as only short-term solutions to the overall challenge of drug-resistant bacteria.Objective:Recently, nanoantibiotics (nAbts) have been of tremendous interest in overcoming the drug resistance developed by several pathogenic microorganisms against most of the commonly used antibiotics. Compared with free antibiotic at the same concentration, drug delivered via a nanoparticle carrier has a much more prominent inhibitory effect on bacterial growth, and drug toxicity, along with prolonged drug release. Additionally, multiple drugs or antimicrobials can be packaged within the same smart polymer which can be designed with stimuli-responsive linkers. These stimuli-responsive nAbts open up the possibility of creating multipurpose and targeted antimicrobials. Biofilm formation still remains the leading cause of conventional antibiotic treatment failure. In contrast to conventional antibiotics nAbts easily penetrate into the biofilm, and selectively target biofilm matrix constituents through the introduction of bacteria specific ligands. In this context, various nanoparticles can be stabilized and functionalized with conventional antibiotics. These composites have a largely enhanced bactericidal efficiency compared to the free antibiotic.Conclusion:Nanoparticle-based carriers deliver antibiotics with better biofilm penetration and lower toxicity, thus combating bacterial resistance. However, the successful adaptation of nanoformulations to clinical practice involves a detailed assessment of their safety profiles and potential immunotoxicity.
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Affiliation(s)
- Ayse Basak Engin
- Faculty of Pharmacy, Department of Toxicology, Gazi University, Ankara, Turkey
| | - Atilla Engin
- Faculty of Medicine, Department of General Surgery, Gazi University, Ankara, Turkey
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91
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Modular Diversity of the BLUF Proteins and Their Potential for the Development of Diverse Optogenetic Tools. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9183924] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Organisms can respond to varying light conditions using a wide range of sensory photoreceptors. These photoreceptors can be standalone proteins or represent a module in multidomain proteins, where one or more modules sense light as an input signal which is converted into an output response via structural rearrangements in these receptors. The output signals are utilized downstream by effector proteins or multiprotein clusters to modulate their activity, which could further affect specific interactions, gene regulation or enzymatic catalysis. The blue-light using flavin (BLUF) photosensory module is an autonomous unit that is naturally distributed among functionally distinct proteins. In this study, we identified 34 BLUF photoreceptors of prokaryotic and eukaryotic origin from available bioinformatics sequence databases. Interestingly, our analysis shows diverse BLUF-effector arrangements with a functional association that was previously unknown or thought to be rare among the BLUF class of sensory proteins, such as endonucleases, tet repressor family (tetR), regulators of G-protein signaling, GAL4 transcription family and several other previously unidentified effectors, such as RhoGEF, Phosphatidyl-Ethanolamine Binding protein (PBP), ankyrin and leucine-rich repeats. Interaction studies and the indexing of BLUF domains further show the diversity of BLUF-effector combinations. These diverse modular architectures highlight how the organism’s behaviour, cellular processes, and distinct cellular outputs are regulated by integrating BLUF sensing modules in combination with a plethora of diverse signatures. Our analysis highlights the modular diversity of BLUF containing proteins and opens the possibility of creating a rational design of novel functional chimeras using a BLUF architecture with relevant cellular effectors. Thus, the BLUF domain could be a potential candidate for the development of powerful novel optogenetic tools for its application in modulating diverse cell signaling.
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92
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McLean K, Lee D, Holmes EA, Penewit K, Waalkes A, Ren M, Lee SA, Gasper J, Manoil C, Salipante SJ. Genomic Analysis Identifies Novel Pseudomonas aeruginosa Resistance Genes under Selection during Inhaled Aztreonam Therapy In Vivo. Antimicrob Agents Chemother 2019; 63:e00866-19. [PMID: 31285231 PMCID: PMC6709462 DOI: 10.1128/aac.00866-19] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 06/28/2019] [Indexed: 12/13/2022] Open
Abstract
Inhaled aztreonam is increasingly used for chronic Pseudomonas aeruginosa suppression in patients with cystic fibrosis (CF), but the potential for that organism to evolve aztreonam resistance remains incompletely explored. Here, we performed genomic analysis of clonally related pre- and posttreatment CF clinical isolate pairs to identify genes that are under positive selection during aztreonam therapy in vivo We identified 16 frequently mutated genes associated with aztreonam resistance, the most prevalent being ftsI and ampC, and 13 of which increased aztreonam resistance when introduced as single gene transposon mutants. Several previously implicated aztreonam resistance genes were found to be under positive selection in clinical isolates even in the absence of inhaled aztreonam exposure, indicating that other selective pressures in the cystic fibrosis airway can promote aztreonam resistance. Given its potential to confer plasmid-mediated resistance, we further characterized mutant ampC alleles and performed artificial evolution of ampC for maximal activity against aztreonam. We found that naturally occurring ampC mutants conferred variably increased resistance to aztreonam (2- to 64-fold) and other β-lactam agents but that its maximal evolutionary capacity for hydrolyzing aztreonam was considerably higher (512- to 1,024-fold increases) and was achieved while maintaining or increasing resistance to other drugs. These studies implicate novel chromosomal aztreonam resistance determinants while highlighting that different mutations are favored during selection in vivo and in vitro, show that ampC has a high maximal potential to hydrolyze aztreonam, and provide an approach to disambiguate mutations promoting specific resistance phenotypes from those more generally increasing bacterial fitness in vivo.
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Affiliation(s)
- Kathryn McLean
- Department of Laboratory Medicine, University of Washington School of Medicine, Seattle, Washington, USA
| | - Duankun Lee
- Department of Laboratory Medicine, University of Washington School of Medicine, Seattle, Washington, USA
| | - Elizabeth A Holmes
- Department of Laboratory Medicine, University of Washington School of Medicine, Seattle, Washington, USA
| | - Kelsi Penewit
- Department of Laboratory Medicine, University of Washington School of Medicine, Seattle, Washington, USA
| | - Adam Waalkes
- Department of Laboratory Medicine, University of Washington School of Medicine, Seattle, Washington, USA
| | - Mingxin Ren
- Department of Laboratory Medicine, University of Washington School of Medicine, Seattle, Washington, USA
| | - Samuel A Lee
- Department of Genome Sciences, University of Washington, Seattle, Washington, USA
| | - Joseph Gasper
- Department of Genome Sciences, University of Washington, Seattle, Washington, USA
| | - Colin Manoil
- Department of Genome Sciences, University of Washington, Seattle, Washington, USA
| | - Stephen J Salipante
- Department of Laboratory Medicine, University of Washington School of Medicine, Seattle, Washington, USA
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93
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Hendiani S, Rybtke ML, Tolker-Nielsen T, Kashef N. Sub-lethal antimicrobial photodynamic inactivation affects Pseudomonas aeruginosa PAO1 quorum sensing and cyclic di-GMP regulatory systems. Photodiagnosis Photodyn Ther 2019; 27:467-473. [PMID: 31362113 DOI: 10.1016/j.pdpdt.2019.07.025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 07/02/2019] [Accepted: 07/26/2019] [Indexed: 10/26/2022]
Abstract
BACKGROUND Antimicrobial photodynamic inactivation (APDI) is a new therapeutic modality which needs more precision during application due to the possibility of exposure of bacteria to sub-lethal doses (sAPDI). In this study, we aimed to evaluate the effect of sAPDI on Pseudomonas aeruginosa quorum sensing (QS) and c-di-GMP signaling which are important virulence factor regulatory systems. METHODS Biofilm formation, pyoverdine, pyocyanin and protease production of P. aeruginosa was evaluated before and after a single sAPDI treatment with 0.8 mM methylene blue (MB) plus 1, 2, and 5-min irradiation with red laser light. Fluorescent lasB, rhlA, pqsA, and cdrA reporters of P. aeruginosa PAO1 and P. aeruginosa ΔmexAB-oprM were treated individually with sAPDI and the regulatory signals were detected. The gene expressions were also assessed after sAPDI using quantitative real-time PCR analysis. RESULTS Morphological observations and molecular assessments indicated that sAPDI with 0.8 mM MB along with 2- and 5-min irradiation led to an increase in the expression of the Las QS system and c-di-GMP signaling, while 1 min irradiation revealed dissimilar results (increase in lasB expression and decrease in c-di-GMP levels). Expression of rhlA and pqsA did not change in response to sAPDI. Further, a severe lethal effect of sAPDI was observed in P. aeruginosa ΔmexAB-oprM as compared with the wild type strain, whilst there was no difference in QS and c-di-GMP levels as detected by reporters between treated and untreated samples. CONCLUSION The results suggest that sAPDI affects QS and c-di-GMP signaling inP. aeruginosa in a time-dependent manner.
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Affiliation(s)
- Saghar Hendiani
- Department of Microbiology, School of Biology, College of Science, University of Tehran, Tehran, Iran.
| | - Morten Levin Rybtke
- Costerton Biofilm Center, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
| | - Tim Tolker-Nielsen
- Costerton Biofilm Center, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
| | - Nasim Kashef
- Department of Microbiology, School of Biology, College of Science, University of Tehran, Tehran, Iran.
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94
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Xin L, Zeng Y, Sheng S, Chea RA, Liu Q, Li HY, Yang L, Xu L, Chiam KH, Liang ZX. Regulation of flagellar motor switching by c-di-GMP phosphodiesterases in Pseudomonas aeruginosa. J Biol Chem 2019; 294:13789-13799. [PMID: 31350333 DOI: 10.1074/jbc.ra119.009009] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 07/23/2019] [Indexed: 12/12/2022] Open
Abstract
The second messenger cyclic diguanylate (c-di-GMP) plays a prominent role in regulating flagellum-dependent motility in the single-flagellated pathogenic bacterium Pseudomonas aeruginosa The c-di-GMP-mediated signaling pathways and mechanisms that control flagellar output remain to be fully unveiled. Studying surface-tethered and free-swimming P. aeruginosa PAO1 cells, we found that the overexpression of an exogenous diguanylate cyclase (DGC) raises the global cellular c-di-GMP concentration and thereby inhibits flagellar motor switching and decreases motor speed, reducing swimming speed and reversal frequency, respectively. We noted that the inhibiting effect of c-di-GMP on flagellar motor switching, but not motor speed, is exerted through the c-di-GMP-binding adaptor protein MapZ and associated chemotactic pathways. Among the 22 putative c-di-GMP phosphodiesterases, we found that three of them (DipA, NbdA, and RbdA) can significantly inhibit flagellar motor switching and swimming directional reversal in a MapZ-dependent manner. These results disclose a network of c-di-GMP-signaling proteins that regulate chemotactic responses and flagellar motor switching in P. aeruginosa and establish MapZ as a key signaling hub that integrates inputs from different c-di-GMP-signaling pathways to control flagellar output and bacterial motility. We rationalized these experimental findings by invoking a model that postulates the regulation of flagellar motor switching by subcellular c-di-GMP pools.
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Affiliation(s)
- Lingyi Xin
- School of Biological Sciences, Nanyang Technological University, 637551, Singapore
| | - Yukai Zeng
- Bioinformatics Institute (A*STAR), S138671, Singapore
| | - Shuo Sheng
- Guangdong Innovative and Entrepreneurial Research Team of Sociomicrobiology Basic Science and Frontier Technology, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou 510642, China
| | - Rachel Andrea Chea
- School of Biological Sciences, Nanyang Technological University, 637551, Singapore
| | - Qiong Liu
- Guangdong Innovative and Entrepreneurial Research Team of Sociomicrobiology Basic Science and Frontier Technology, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou 510642, China
| | - Hoi Yeung Li
- School of Biological Sciences, Nanyang Technological University, 637551, Singapore
| | - Liang Yang
- School of Biological Sciences, Nanyang Technological University, 637551, Singapore.,Interdisciplinary Graduate School, Nanyang Technological University, S637551, Singapore.,Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, 637551, Singapore
| | - Linghui Xu
- Guangdong Innovative and Entrepreneurial Research Team of Sociomicrobiology Basic Science and Frontier Technology, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou 510642, China.,Key Laboratory of Bio-Pesticide Innovation and Application of Guangdong Province, South China Agricultural University, Guangzhou 510642, China
| | | | - Zhao-Xun Liang
- School of Biological Sciences, Nanyang Technological University, 637551, Singapore .,Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, 637551, Singapore
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95
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Kim SK, Lormand JD, Weiss CA, Eger KA, Turdiev H, Turdiev A, Winkler WC, Sondermann H, Lee VT. A dedicated diribonucleotidase resolves a key bottleneck for the terminal step of RNA degradation. eLife 2019; 8:46313. [PMID: 31225796 PMCID: PMC6613908 DOI: 10.7554/elife.46313] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 06/14/2019] [Indexed: 12/28/2022] Open
Abstract
Degradation of RNA polymers, an ubiquitous process in all cells, is catalyzed by specific subsets of endo- and exoribonucleases that together recycle RNA fragments into nucleotide monophosphate. In γ-proteobacteria, 3-'5' exoribonucleases comprise up to eight distinct enzymes. Among them, Oligoribonuclease (Orn) is unique as its activity is required for clearing short RNA fragments, which is important for cellular fitness. However, the molecular basis of Orn's unique cellular function remained unclear. Here, we show that Orn exhibits exquisite substrate preference for diribonucleotides. Crystal structures of substrate-bound Orn reveal an active site optimized for diribonucleotides. While other cellular RNases process oligoribonucleotides down to diribonucleotide entities, Orn is the one and only diribonucleotidase that completes the terminal step of RNA degradation. Together, our studies indicate RNA degradation as a step-wise process with a dedicated enzyme for the clearance of a specific intermediate pool, diribonucleotides, that affects cellular physiology and viability.
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Affiliation(s)
- Soo-Kyoung Kim
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, United States
| | - Justin D Lormand
- Department of Molecular Medicine, College of Veterinary Medicine, Cornell University, Ithaca, United States
| | - Cordelia A Weiss
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, United States
| | - Karin A Eger
- Department of Molecular Medicine, College of Veterinary Medicine, Cornell University, Ithaca, United States
| | - Husan Turdiev
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, United States
| | - Asan Turdiev
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, United States
| | - Wade C Winkler
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, United States
| | - Holger Sondermann
- Department of Molecular Medicine, College of Veterinary Medicine, Cornell University, Ithaca, United States
| | - Vincent T Lee
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, United States
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96
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Fitting Pieces into the Puzzle of Pseudomonas aeruginosa Type III Secretion System Gene Expression. J Bacteriol 2019; 201:JB.00209-19. [PMID: 31010903 DOI: 10.1128/jb.00209-19] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Type III secretion systems (T3SS) are widely distributed in Gram-negative microorganisms and critical for host-pathogen and host-symbiont interactions with plants and animals. Central features of the T3SS are a highly conserved set of secretion and translocation genes and contact dependence wherein host-pathogen interactions trigger effector protein delivery and serve as an inducing signal for T3SS gene expression. In addition to these conserved features, there are pathogen-specific properties that include a unique repertoire of effector genes and mechanisms to control T3SS gene expression. The Pseudomonas aeruginosa T3SS serves as a model system to understand transcriptional and posttranscriptional mechanisms involved in the control of T3SS gene expression. The central regulatory feature is a partner-switching system that controls the DNA-binding activity of ExsA, the primary regulator of T3SS gene expression. Superimposed upon the partner-switching mechanism are cyclic AMP and cyclic di-GMP signaling systems, two-component systems, global regulators, and RNA-binding proteins that have positive and negative effects on ExsA transcription and/or synthesis. In the present review, we discuss advances in our understanding of how these regulatory systems orchestrate the activation of T3SS gene expression in the context of acute infections and repression of the T3SS as P. aeruginosa adapts to and colonizes the cystic fibrosis airways.
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97
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Armbruster CR, Lee CK, Parker-Gilham J, de Anda J, Xia A, Zhao K, Murakami K, Tseng BS, Hoffman LR, Jin F, Harwood CS, Wong GCL, Parsek MR. Heterogeneity in surface sensing suggests a division of labor in Pseudomonas aeruginosa populations. eLife 2019; 8:e45084. [PMID: 31180327 PMCID: PMC6615863 DOI: 10.7554/elife.45084] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 06/08/2019] [Indexed: 12/27/2022] Open
Abstract
The second messenger signaling molecule cyclic diguanylate monophosphate (c-di-GMP) drives the transition between planktonic and biofilm growth in many bacterial species. Pseudomonas aeruginosa has two surface sensing systems that produce c-di-GMP in response to surface adherence. Current thinking in the field is that once cells attach to a surface, they uniformly respond by producing c-di-GMP. Here, we describe how the Wsp system generates heterogeneity in surface sensing, resulting in two physiologically distinct subpopulations of cells. One subpopulation has elevated c-di-GMP and produces biofilm matrix, serving as the founders of initial microcolonies. The other subpopulation has low c-di-GMP and engages in surface motility, allowing for exploration of the surface. We also show that this heterogeneity strongly correlates to surface behavior for descendent cells. Together, our results suggest that after surface attachment, P. aeruginosa engages in a division of labor that persists across generations, accelerating early biofilm formation and surface exploration.
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Affiliation(s)
| | - Calvin K Lee
- Department of BioengineeringUniversity of California, Los AngelesLos AngelesUnited States
- Department of Chemistry and BiochemistryUniversity of California, Los AngelesLos AngelesUnited States
- California NanoSystems InstituteUniversity of California, Los AngelesLos AngelesUnited States
| | | | - Jaime de Anda
- Department of BioengineeringUniversity of California, Los AngelesLos AngelesUnited States
- Department of Chemistry and BiochemistryUniversity of California, Los AngelesLos AngelesUnited States
- California NanoSystems InstituteUniversity of California, Los AngelesLos AngelesUnited States
| | - Aiguo Xia
- Hefei National Laboratory for Physical Sciences at the MicroscaleUniversity of Science and Technology of ChinaHefeiChina
| | - Kun Zhao
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and TechnologyTianjin UniversityTianjinChina
- Collaborative Innovation Centre of Chemical Science and EngineeringTianjin UniversityTianjinChina
| | - Keiji Murakami
- Department of Oral Microbiology, Institute of Biomedical SciencesTokushima University Graduate SchoolTokushimaJapan
| | - Boo Shan Tseng
- School of Life SciencesUniversity of NevadaLas VegasUnited States
| | - Lucas R Hoffman
- Department of MicrobiologyUniversity of WashingtonSeattleUnited States
- Department of PediatricsUniversity of WashingtonSeattleUnited States
| | - Fan Jin
- Hefei National Laboratory for Physical Sciences at the MicroscaleUniversity of Science and Technology of ChinaHefeiChina
- Institute of Synthetic BiologyShenzhen Institutes of Advanced Technology, Chinese Academy of SciencesShenzhenChina
| | | | - Gerard CL Wong
- Department of BioengineeringUniversity of California, Los AngelesLos AngelesUnited States
- Department of Chemistry and BiochemistryUniversity of California, Los AngelesLos AngelesUnited States
- California NanoSystems InstituteUniversity of California, Los AngelesLos AngelesUnited States
| | - Matthew R Parsek
- Department of MicrobiologyUniversity of WashingtonSeattleUnited States
- Integrative Microbiology Research CentreSouth China Agricultural UniversityGuangzhouChina
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98
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Little RH, Woodcock SD, Campilongo R, Fung RKY, Heal R, Humphries L, Pacheco-Moreno A, Paulusch S, Stigliano E, Vikeli E, Ward D, Malone JG. Differential Regulation of Genes for Cyclic-di-GMP Metabolism Orchestrates Adaptive Changes During Rhizosphere Colonization by Pseudomonas fluorescens. Front Microbiol 2019; 10:1089. [PMID: 31156596 PMCID: PMC6531821 DOI: 10.3389/fmicb.2019.01089] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 04/30/2019] [Indexed: 12/02/2022] Open
Abstract
Bacteria belonging to the Pseudomonas genus are highly successful colonizers of the plant rhizosphere. The ability of different Pseudomonas species to live either commensal lifestyles or to act as agents of plant-growth promotion or disease is reflected in a large, highly flexible accessory genome. Nevertheless, adaptation to the plant environment involves a commonality of phenotypic outputs such as changes to motility, coupled with synthesis of nutrient uptake systems, stress-response molecules and adherence factors including exopolysaccharides. Cyclic-di-GMP (cdG) is a highly important second messenger involved in the integration of environmental signals with appropriate adaptive responses and is known to play a central role in mediating effective rhizosphere colonization. In this study, we examined the transcription of multiple, reportedly plant-upregulated cdG metabolism genes during colonization of the wheat rhizosphere by the plant-growth-promoting strain P. fluorescens SBW25. While transcription of the tested genes generally increased in the rhizosphere environment, we additionally observed a tightly orchestrated response to environmental cues, with a distinct transcriptional pattern seen for each gene throughout the colonization process. Extensive phenotypical analysis of deletion and overexpression strains was then conducted and used to propose cellular functions for individual cdG signaling genes. Finally, in-depth genetic analysis of an important rhizosphere colonization regulator revealed a link between cdG control of growth, motility and stress response, and the carbon sources available in the rhizosphere.
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Affiliation(s)
- Richard H Little
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Stuart D Woodcock
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Rosaria Campilongo
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Rowena K Y Fung
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Robert Heal
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Libby Humphries
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Alba Pacheco-Moreno
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | | | - Egidio Stigliano
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Eleni Vikeli
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Danny Ward
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Jacob G Malone
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom.,School of Biological Sciences, University of East Anglia, Norwich, United Kingdom
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99
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Pleiotropic Effects of c-di-GMP Content in Pseudomonas syringae. Appl Environ Microbiol 2019; 85:AEM.00152-19. [PMID: 30850427 PMCID: PMC6498148 DOI: 10.1128/aem.00152-19] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 02/27/2019] [Indexed: 12/27/2022] Open
Abstract
The present work comprehensively analyzed the transcriptome and phenotypes that were regulated by c-di-GMP in P. syringae. Given that the majority of diguanylate cyclases and phosphodiesterases have not been characterized in P. syringae, this work provided a very useful database for the future study on regulatory mechanism (especially its relationship with T3SS) of c-di-GMP in P. syringae. In particular, we identified three promoters that were sensitive to elevated c-di-GMP levels and inserted them into luciferase-based reporters that effectively respond to intracellular levels of c-di-GMP in P. syringae, which could be used as an economic and efficient way to measure relative c-di-GMP levels in vivo in the future. Although the ubiquitous bacterial secondary messenger cyclic diguanylate (c-di-GMP) has important cellular functions in a wide range of bacteria, its function in the model plant pathogen Pseudomonas syringae remains largely elusive. To this end, we overexpressed Escherichia coli diguanylate cyclase (YedQ) and phosphodiesterase (YhjH) in P. syringae, resulting in high and low in vivo levels of c-di-GMP, respectively. Via genome-wide RNA sequencing of these two strains, we found that c-di-GMP regulates (i) fliN, fliE, and flhA, which are associated with flagellar assembly; (ii) alg8 and alg44, which are related to the exopolysaccharide biosynthesis pathway; (iii) pvdE, pvdP, and pvsA, which are associated with the siderophore biosynthesis pathway; and (iv) sodA, which encodes a superoxide dismutase. In particular, we identified three promoters that are sensitive to elevated levels of c-di-GMP and inserted them into luciferase-based reporters that respond effectively to the c-di-GMP levels in P. syringae; these promoters could be useful in the measurement of in vivo levels of c-di-GMP in real time. Further phenotypic assays validated the RNA sequencing (RNA-seq) results and confirmed the effect on c-di-GMP-associated pathways, such as repressing the type III secretion system (T3SS) and motility while inducing biofilm production, siderophore production, and oxidative stress resistance. Taken together, these results demonstrate that c-di-GMP regulates the virulence and stress response in P. syringae, which suggests that tuning its level could be a new strategy to protect plants from attacks by this pathogen. IMPORTANCE The present work comprehensively analyzed the transcriptome and phenotypes that were regulated by c-di-GMP in P. syringae. Given that the majority of diguanylate cyclases and phosphodiesterases have not been characterized in P. syringae, this work provided a very useful database for the future study on regulatory mechanism (especially its relationship with T3SS) of c-di-GMP in P. syringae. In particular, we identified three promoters that were sensitive to elevated c-di-GMP levels and inserted them into luciferase-based reporters that effectively respond to intracellular levels of c-di-GMP in P. syringae, which could be used as an economic and efficient way to measure relative c-di-GMP levels in vivo in the future.
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100
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Martini MC, Zhou Y, Sun H, Shell SS. Defining the Transcriptional and Post-transcriptional Landscapes of Mycobacterium smegmatis in Aerobic Growth and Hypoxia. Front Microbiol 2019; 10:591. [PMID: 30984135 PMCID: PMC6448022 DOI: 10.3389/fmicb.2019.00591] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Accepted: 03/08/2019] [Indexed: 12/13/2022] Open
Abstract
The ability of Mycobacterium tuberculosis to infect, proliferate, and survive during long periods in the human lungs largely depends on the rigorous control of gene expression. Transcriptome-wide analyses are key to understanding gene regulation on a global scale. Here, we combine 5′-end-directed libraries with RNAseq expression libraries to gain insight into the transcriptome organization and post-transcriptional mRNA cleavage landscape in mycobacteria during log phase growth and under hypoxia, a physiologically relevant stress condition. Using the model organism Mycobacterium smegmatis, we identified 6,090 transcription start sites (TSSs) with high confidence during log phase growth, of which 67% were categorized as primary TSSs for annotated genes, and the remaining were classified as internal, antisense, or orphan, according to their genomic context. Interestingly, over 25% of the RNA transcripts lack a leader sequence, and of the coding sequences that do have leaders, 53% lack a strong consensus Shine-Dalgarno site. This indicates that like M. tuberculosis, M. smegmatis can initiate translation through multiple mechanisms. Our approach also allowed us to identify over 3,000 RNA cleavage sites, which occur at a novel sequence motif. To our knowledge, this represents the first report of a transcriptome-wide RNA cleavage site map in mycobacteria. The cleavage sites show a positional bias toward mRNA regulatory regions, highlighting the importance of post-transcriptional regulation in gene expression. We show that in low oxygen, a condition associated with the host environment during infection, mycobacteria change their transcriptomic profiles and endonucleolytic RNA cleavage is markedly reduced, suggesting a mechanistic explanation for previous reports of increased mRNA half-lives in response to stress. In addition, a number of TSSs were triggered in hypoxia, 56 of which contain the binding motif for the sigma factor SigF in their promoter regions. This suggests that SigF makes direct contributions to transcriptomic remodeling in hypoxia-challenged mycobacteria. Taken together, our data provide a foundation for further study of both transcriptional and posttranscriptional regulation in mycobacteria.
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Affiliation(s)
- M Carla Martini
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA, United States
| | - Ying Zhou
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA, United States
| | - Huaming Sun
- Program in Bioinformatics and Computational Biology, Worcester Polytechnic Institute, Worcester, MA, United States
| | - Scarlet S Shell
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA, United States.,Program in Bioinformatics and Computational Biology, Worcester Polytechnic Institute, Worcester, MA, United States
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