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Wang R, Zhang Z, Yu X, Song Y, Shentu X. CdgB Regulates Morphological Differentiation and Toyocamycin Production in Streptomyces diastatochromogenes 1628. Int J Mol Sci 2024; 25:3878. [PMID: 38612686 PMCID: PMC11012013 DOI: 10.3390/ijms25073878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 03/26/2024] [Accepted: 03/28/2024] [Indexed: 04/14/2024] Open
Abstract
Bis (3',5')-cyclic diguanylic acid (c-di-GMP) is a ubiquitous second messenger that controls several metabolic pathways in bacteria. In Streptomyces, c-di-GMP is associated with morphological differentiation, which is related to secondary metabolite production. In this study, we identified and characterized a diguanylate cyclase (DGC), CdgB, from Streptomyces diastatochromogenes 1628, which may be involved in c-di-GMP synthesis, through genetic and biochemical analyses. To further investigate the role of CdgB, the cdgB-deleted mutant strain Δ-cdgB and the cdgB-overexpressing mutant strain O-cdgB were constructed by genetic engineering. A phenotypic analysis revealed that the O-cdgB colonies exhibited reduced mycelium formation, whereas the Δ-cdgB colonies displayed wrinkled surfaces and shriveled mycelia. Notably, O-cdgB demonstrated a significant increase in the toyocamycin (TM) yield by 47.3%, from 253 to 374 mg/L, within 10 days. This increase was accompanied by a 6.7% elevation in the intracellular concentration of c-di-GMP and a higher transcriptional level of the toy cluster within four days. Conversely, Δ-cdgB showed a lower c-di-GMP concentration (reduced by 6.2%) in vivo and a reduced toyocamycin production (decreased by 28.9%, from 253 to 180 mg/L) after 10 days. In addition, S. diastatochromogenes 1628 exhibited a slightly higher inhibitory effect against Fusarium oxysporum f. sp. cucumerinum and Rhizoctonia solani compared to Δ-cdgB, but a lower inhibition rate than that of O-cdgB. The results imply that CdgB provides a foundational function for metabolism and the activation of secondary metabolism in S. diastatochromogenes 1628.
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Affiliation(s)
- Rui Wang
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection and Quarantine, College of Life Science, China Jiliang University, Hangzhou 310018, China (X.Y.)
| | - Zixuan Zhang
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection and Quarantine, College of Life Science, China Jiliang University, Hangzhou 310018, China (X.Y.)
| | - Xiaoping Yu
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection and Quarantine, College of Life Science, China Jiliang University, Hangzhou 310018, China (X.Y.)
| | - Yang Song
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection and Quarantine, College of Life Science, China Jiliang University, Hangzhou 310018, China (X.Y.)
- Department of Chemistry, Zhejiang University, Hangzhou 310027, China
| | - Xuping Shentu
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection and Quarantine, College of Life Science, China Jiliang University, Hangzhou 310018, China (X.Y.)
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2
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Ruhluel D, Fisher L, Barton TE, Leighton H, Kumar S, Amores Morillo P, O’Brien S, Fothergill JL, Neill DR. Secondary messenger signalling influences Pseudomonas aeruginosa adaptation to sinus and lung environments. THE ISME JOURNAL 2024; 18:wrae065. [PMID: 38647527 PMCID: PMC11102083 DOI: 10.1093/ismejo/wrae065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Revised: 03/08/2024] [Accepted: 04/18/2024] [Indexed: 04/25/2024]
Abstract
Pseudomonas aeruginosa is a cause of chronic respiratory tract infections in people with cystic fibrosis (CF), non-CF bronchiectasis, and chronic obstructive pulmonary disease. Prolonged infection allows the accumulation of mutations and horizontal gene transfer, increasing the likelihood of adaptive phenotypic traits. Adaptation is proposed to arise first in bacterial populations colonizing upper airway environments. Here, we model this process using an experimental evolution approach. Pseudomonas aeruginosa PAO1, which is not airway adapted, was serially passaged, separately, in media chemically reflective of upper or lower airway environments. To explore whether the CF environment selects for unique traits, we separately passaged PAO1 in airway-mimicking media with or without CF-specific factors. Our findings demonstrated that all airway environments-sinus and lungs, under CF and non-CF conditions-selected for loss of twitching motility, increased resistance to multiple antibiotic classes, and a hyper-biofilm phenotype. These traits conferred increased airway colonization potential in an in vivo model. CF-like conditions exerted stronger selective pressures, leading to emergence of more pronounced phenotypes. Loss of twitching was associated with mutations in type IV pili genes. Type IV pili mediate surface attachment, twitching, and induction of cAMP signalling. We additionally identified multiple evolutionary routes to increased biofilm formation involving regulation of cyclic-di-GMP signalling. These included the loss of function mutations in bifA and dipA phosphodiesterase genes and activating mutations in the siaA phosphatase. These data highlight that airway environments select for traits associated with sessile lifestyles and suggest upper airway niches support emergence of phenotypes that promote establishment of lung infection.
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Affiliation(s)
- Dilem Ruhluel
- Department of Clinical Infection, Microbiology and Immunology, University of Liverpool, Ronald Ross Building, 8 West Derby Street, Liverpool, United Kingdom
| | - Lewis Fisher
- Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge, United Kingdom
| | - Thomas E Barton
- Division of Molecular Microbiology, University of Dundee, Dow Street, Dundee, United Kingdom
| | - Hollie Leighton
- Department of Clinical Infection, Microbiology and Immunology, University of Liverpool, Ronald Ross Building, 8 West Derby Street, Liverpool, United Kingdom
| | - Sumit Kumar
- Division of Molecular Microbiology, University of Dundee, Dow Street, Dundee, United Kingdom
| | - Paula Amores Morillo
- Department of Clinical Infection, Microbiology and Immunology, University of Liverpool, Ronald Ross Building, 8 West Derby Street, Liverpool, United Kingdom
| | - Siobhan O’Brien
- Department of Microbiology, Moyne Institute of Preventive Medicine, Trinity College, Dublin, 2, Ireland
| | - Joanne L Fothergill
- Department of Clinical Infection, Microbiology and Immunology, University of Liverpool, Ronald Ross Building, 8 West Derby Street, Liverpool, United Kingdom
| | - Daniel R Neill
- Division of Molecular Microbiology, University of Dundee, Dow Street, Dundee, United Kingdom
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3
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Ellis NA, Myers KS, Tung J, Davidson Ward A, Johnston K, Bonnington KE, Donohue TJ, Machner MP. A randomized multiplex CRISPRi-Seq approach for the identification of critical combinations of genes. eLife 2023; 12:RP86903. [PMID: 38095310 PMCID: PMC10721215 DOI: 10.7554/elife.86903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2023] Open
Abstract
Identifying virulence-critical genes from pathogens is often limited by functional redundancy. To rapidly interrogate the contributions of combinations of genes to a biological outcome, we have developed a multiplex, randomized CRISPR interference sequencing (MuRCiS) approach. At its center is a new method for the randomized self-assembly of CRISPR arrays from synthetic oligonucleotide pairs. When paired with PacBio long-read sequencing, MuRCiS allowed for near-comprehensive interrogation of all pairwise combinations of a group of 44 Legionella pneumophila virulence genes encoding highly conserved transmembrane proteins for their role in pathogenesis. Both amoeba and human macrophages were challenged with L. pneumophila bearing the pooled CRISPR array libraries, leading to the identification of several new virulence-critical combinations of genes. lpg2888 and lpg3000 were particularly fascinating for their apparent redundant functions during L. pneumophila human macrophage infection, while lpg3000 alone was essential for L. pneumophila virulence in the amoeban host Acanthamoeba castellanii. Thus, MuRCiS provides a method for rapid genetic examination of even large groups of redundant genes, setting the stage for application of this technology to a variety of biological contexts and organisms.
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Affiliation(s)
- Nicole A Ellis
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
| | - Kevin S Myers
- Great Lakes Bioenergy Research Center, University of Wisconsin-MadisonMadisonUnited States
- Wisconsin Energy Institute, University of Wisconsin-MadisonMadisonUnited States
| | - Jessica Tung
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
| | - Anne Davidson Ward
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
| | - Kathryn Johnston
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
| | - Katherine E Bonnington
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
| | - Timothy J Donohue
- Great Lakes Bioenergy Research Center, University of Wisconsin-MadisonMadisonUnited States
- Wisconsin Energy Institute, University of Wisconsin-MadisonMadisonUnited States
- Department of Bacteriology, University of Wisconsin-MadisonMadisonUnited States
| | - Matthias P Machner
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
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4
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Ellis NA, Myers KS, Tung J, Ward AD, Johnston K, Bonnington KE, Donohue TJ, Machner MP. A randomized multiplex CRISPRi-Seq approach for the identification of critical combinations of genes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.03.527066. [PMID: 36945652 PMCID: PMC10028747 DOI: 10.1101/2023.02.03.527066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Identifying virulence-critical genes from pathogens is often limited by functional redundancy. To rapidly interrogate the contributions of combinations of genes to a biological outcome, we have developed a multiplex, randomized CRISPR interference sequencing (MuRCiS) approach. At its center is a new method for the randomized self-assembly of CRISPR arrays from synthetic oligonucleotide pairs. When paired with PacBio long-read sequencing, MuRCiS allowed for near-comprehensive interrogation of all pairwise combinations of a group of 44 Legionella pneumophila virulence genes encoding highly conserved transmembrane proteins for their role in pathogenesis. Both amoeba and human macrophages were challenged with L. pneumophila bearing the pooled CRISPR array libraries, leading to the identification of several new virulence-critical combinations of genes. lpg2888 and lpg3000 were particularly fascinating for their apparent redundant functions during L. pneumophila human macrophage infection, while lpg3000 alone was essential for L. pneumophila virulence in the amoeban host Acanthamoeba castellanii. Thus, MuRCiS provides a method for rapid genetic examination of even large groups of redundant genes, setting the stage for application of this technology to a variety of biological contexts and organisms.
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Affiliation(s)
- Nicole A. Ellis
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Kevin S. Myers
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Wisconsin Energy Institute, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Jessica Tung
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Anne Davidson Ward
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Kathryn Johnston
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Katherine E. Bonnington
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Timothy J. Donohue
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Wisconsin Energy Institute, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Matthias P. Machner
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
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5
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Koppenhöfer S, Lang AS. Patterns of abundance, chromosomal localization, and domain organization among c-di-GMP-metabolizing genes revealed by comparative genomics of five alphaproteobacterial orders. BMC Genomics 2022; 23:834. [PMID: 36522693 PMCID: PMC9756655 DOI: 10.1186/s12864-022-09072-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 10/17/2022] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP) is a bacterial second messenger that affects diverse processes in different bacteria, including the cell cycle, motility, and biofilm formation. Its cellular levels are controlled by the opposing activities of two types of enzymes, with synthesis by diguanylate cyclases containing a GGDEF domain and degradation by phosphodiesterases containing either an HD-GYP or an EAL domain. These enzymes are ubiquitous in bacteria with up to 50 encoded in some genomes, the specific functions of which are mostly unknown. RESULTS We used comparative analyses to identify genomic patterns among genes encoding proteins with GGDEF, EAL, and HD-GYP domains in five orders of the class Alphaproteobacteria. GGDEF-containing sequences and GGDEF-EAL hybrids were the most abundant and had the highest diversity of co-occurring auxiliary domains while EAL and HD-GYP containing sequences were less abundant and less diverse with respect to auxiliary domains. There were striking patterns in the chromosomal localizations of the genes found in two of the orders. The Rhodobacterales' EAL-encoding genes and Rhizobiales' GGDEF-EAL-encoding genes showed opposing patterns of distribution compared to the GGDEF-encoding genes. In the Rhodobacterales, the GGDEF-encoding genes showed a tri-modal distribution with peaks mid-way between the origin (ori) and terminus (ter) of replication and at ter while the EAL-encoding genes peaked near ori. The patterns were more complex in the Rhizobiales, but the GGDEF-encoding genes were biased for localization near ter. CONCLUSIONS The observed patterns in the chromosomal localizations of these genes suggest a coupling of synthesis and hydrolysis of c-di-GMP with the cell cycle. Moreover, the higher proportions and diversities of auxiliary domains associated with GGDEF domains and GGDEF-EAL hybrids compared to EAL or HD-GYP domains could indicate that more stimuli affect synthesis compared to hydrolysis of c-di-GMP.
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Affiliation(s)
- Sonja Koppenhöfer
- grid.25055.370000 0000 9130 6822Department of Biology, Memorial University of Newfoundland, St. John’s, Newfoundland and Labrador Canada
| | - Andrew S. Lang
- grid.25055.370000 0000 9130 6822Department of Biology, Memorial University of Newfoundland, St. John’s, Newfoundland and Labrador Canada
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A c-di-GMP Signaling Cascade Controls Motility, Biofilm Formation, and Virulence in Burkholderia thailandensis. Appl Environ Microbiol 2022; 88:e0252921. [PMID: 35323023 DOI: 10.1128/aem.02529-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
As a key bacterial second messenger, cyclic di-GMP (c-di-GMP) regulates various physiological processes, such as motility, biofilm formation, and virulence. Cellular c-di-GMP levels are regulated by the opposing activities of diguanylate cyclases (DGCs) and phosphodiesterases (PDEs). Beyond that, the enzymatic activities of c-di-GMP metabolizing proteins are controlled by a variety of extracellular signals and intracellular physiological conditions. Here, we report that pdcA (BTH_II2363), pdcB (BTH_II2364), and pdcC (BTH_II2365) are cotranscribed in the same operon and are involved in a regulatory cascade controlling the cellular level of c-di-GMP in Burkholderia thailandensis. The GGDEF domain-containing protein PdcA was found to be a DGC that modulates biofilm formation, motility, and virulence in B. thailandensis. Moreover, the DGC activity of PdcA was inhibited by phosphorylated PdcC, a single-domain response regulator composed of only the phosphoryl-accepting REC domain. The phosphatase PdcB affects the function of PdcA by dephosphorylating PdcC. The observation that homologous operons of pdcABC are widespread among betaproteobacteria and gammaproteobacteria suggests a general mechanism by which the intracellular concentration of c-di-GMP is modulated to coordinate bacterial behavior and virulence. IMPORTANCE The transition from planktonic cells to biofilm cells is a successful strategy adopted by bacteria to survive in diverse environments, while the second messenger c-di-GMP plays an important role in this process. Cellular c-di-GMP levels are mainly controlled by modulating the activity of c-di-GMP-metabolizing proteins via the sensory domains adjacent to their enzymatic domains. However, in most cases how c-di-GMP-metabolizing enzymes are modulated by their sensory domains remains unclear. Here, we reveal a new c-di-GMP signaling cascade that regulates motility, biofilm formation, and virulence in B. thailandensis. While pdcA, pdcB, and pdcC constitute an operon, the phosphorylated PdcC binds the PAS sensory domain of PdcA to inhibit its DGC activity, with PdcB dephosphorylating PdcC to derepress the activity of PdcA. We also show this c-di-GMP regulatory model is widespread in the phylum Proteobacteria. Our study expands the current knowledge of how bacteria regulate intracellular c-di-GMP levels.
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7
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Recent Strategies to Combat Biofilms Using Antimicrobial Agents and Therapeutic Approaches. Pathogens 2022; 11:pathogens11030292. [PMID: 35335616 PMCID: PMC8955104 DOI: 10.3390/pathogens11030292] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 02/11/2022] [Accepted: 02/14/2022] [Indexed: 02/01/2023] Open
Abstract
Biofilms are intricate bacterial assemblages that attach to diverse surfaces using an extracellular polymeric substance that protects them from the host immune system and conventional antibiotics. Biofilms cause chronic infections that result in millions of deaths around the world every year. Since the antibiotic tolerance mechanism in biofilm is different than that of the planktonic cells due to its multicellular structure, the currently available antibiotics are inadequate to treat biofilm-associated infections which have led to an immense need to find newer treatment options. Over the years, various novel antibiofilm compounds able to fight biofilms have been discovered. In this review, we have focused on the recent and intensively researched therapeutic techniques and antibiofilm agents used for biofilm treatment and grouped them according to their type and mode of action. We also discuss some therapeutic approaches that have the potential for future advancement.
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Mahto KU, Kumari S, Das S. Unraveling the complex regulatory networks in biofilm formation in bacteria and relevance of biofilms in environmental remediation. Crit Rev Biochem Mol Biol 2021; 57:305-332. [PMID: 34937434 DOI: 10.1080/10409238.2021.2015747] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Biofilms are assemblages of bacteria embedded within a matrix of extracellular polymeric substances (EPS) attached to a substratum. The process of biofilm formation is a complex phenomenon regulated by the intracellular and intercellular signaling systems. Various secondary messenger molecules such as cyclic dimeric guanosine 3',5'-monophosphate (c-di-GMP), cyclic adenosine 3',5'-monophosphate (cAMP), and cyclic dimeric adenosine 3',5'-monophosphate (c-di-AMP) are involved in complex signaling networks to regulate biofilm development in several bacteria. Moreover, the cell to cell communication system known as Quorum Sensing (QS) also regulates biofilm formation via diverse mechanisms in various bacterial species. Bacteria often switch to the biofilm lifestyle in the presence of toxic pollutants to improve their survivability. Bacteria within a biofilm possess several advantages with regard to the degradation of harmful pollutants, such as increased protection within the biofilm to resist the toxic pollutants, synthesis of extracellular polymeric substances (EPS) that helps in the sequestration of pollutants, elevated catabolic gene expression within the biofilm microenvironment, higher cell density possessing a large pool of genetic resources, adhesion ability to a wide range of substrata, and metabolic heterogeneity. Therefore, a comprehensive account of the various factors regulating biofilm development would provide valuable insights to modulate biofilm formation for improved bioremediation practices. This review summarizes the complex regulatory networks that influence biofilm development in bacteria, with a major focus on the applications of bacterial biofilms for environmental restoration.
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Affiliation(s)
- Kumari Uma Mahto
- Department of Life Science, Laboratory of Environmental Microbiology and Ecology (LEnME), National Institute of Technology, Odisha, India
| | - Swetambari Kumari
- Department of Life Science, Laboratory of Environmental Microbiology and Ecology (LEnME), National Institute of Technology, Odisha, India
| | - Surajit Das
- Department of Life Science, Laboratory of Environmental Microbiology and Ecology (LEnME), National Institute of Technology, Odisha, India
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9
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Functional metagenomic analysis of quorum sensing signaling in a nitrifying community. NPJ Biofilms Microbiomes 2021; 7:79. [PMID: 34711833 PMCID: PMC8553950 DOI: 10.1038/s41522-021-00250-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 10/08/2021] [Indexed: 01/12/2023] Open
Abstract
Quorum sensing (QS) can function to shape the microbial community interactions, composition, and function. In wastewater treatment systems, acylated homoserine lactone (AHL)-based QS has been correlated with the conversion of floccular biomass into microbial granules, as well as EPS production and the nitrogen removal process. However, the role of QS in such complex communities is still not fully understood, including the QS-proficient taxa and the functional QS genes involved. To address these questions, we performed a metagenomic screen for AHL genes in an activated sludge microbial community from the Ulu Pandan wastewater treatment plant (WWTP) in Singapore followed by functional validation of luxI activity using AHL biosensors and LC–MSMS profiling. We identified 13 luxI and 30 luxR homologs from the activated sludge metagenome. Of those genes, two represented a cognate pair of luxIR genes belonging to a Nitrospira spp. and those genes were demonstrated to be functionally active. The LuxI homolog synthesized AHLs that were consistent with the dominant AHLs in the activated sludge system. Furthermore, the LuxR homolog was shown to bind to and induce expression of the luxI promoter, suggesting this represents an autoinduction feedback system, characteristic of QS circuits. Additionally, a second, active promoter was upstream of a gene encoding a protein with a GGDEF/EAL domain, commonly associated with modulating the intracellular concentration of the secondary messenger, c-di-GMP. Thus, the metagenomic approach used here was demonstrated to effectively identify functional QS genes and suggests that Nitrospira spp. maybe QS is active in the activated sludge community.
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10
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Patterson DC, Ruiz MP, Yoon H, Walker JA, Armache JP, Yennawar NH, Weinert EE. Differential ligand-selective control of opposing enzymatic activities within a bifunctional c-di-GMP enzyme. Proc Natl Acad Sci U S A 2021; 118:e2100657118. [PMID: 34475207 PMCID: PMC8433548 DOI: 10.1073/pnas.2100657118] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 08/02/2021] [Indexed: 01/23/2023] Open
Abstract
Cyclic dimeric guanosine monophosphate (c-di-GMP) serves as a second messenger that modulates bacterial cellular processes, including biofilm formation. While proteins containing both c-di-GMP synthesizing (GGDEF) and c-di-GMP hydrolyzing (EAL) domains are widely predicted in bacterial genomes, it is poorly understood how domains with opposing enzymatic activity are regulated within a single polypeptide. Herein, we report the characterization of a globin-coupled sensor protein (GCS) from Paenibacillus dendritiformis (DcpG) with bifunctional c-di-GMP enzymatic activity. DcpG contains a regulatory sensor globin domain linked to diguanylate cyclase (GGDEF) and phosphodiesterase (EAL) domains that are differentially regulated by gas binding to the heme; GGDEF domain activity is activated by the Fe(II)-NO state of the globin domain, while EAL domain activity is activated by the Fe(II)-O2 state. The in vitro activity of DcpG is mimicked in vivo by the biofilm formation of P. dendritiformis in response to gaseous environment, with nitric oxide conditions leading to the greatest amount of biofilm formation. The ability of DcpG to differentially control GGDEF and EAL domain activity in response to ligand binding is likely due to the unusual properties of the globin domain, including rapid ligand dissociation rates and high midpoint potentials. Using structural information from small-angle X-ray scattering and negative stain electron microscopy studies, we developed a structural model of DcpG, providing information about the regulatory mechanism. These studies provide information about full-length GCS protein architecture and insight into the mechanism by which a single regulatory domain can selectively control output domains with opposing enzymatic activities.
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Affiliation(s)
- Dayna C Patterson
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802
| | - Myrrh Perez Ruiz
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802
| | - Hyerin Yoon
- Department of Chemistry, Emory University, Atlanta, GA 30322
| | | | - Jean-Paul Armache
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802
- The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA 16802
| | - Neela H Yennawar
- The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA 16802
| | - Emily E Weinert
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802;
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802
- The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA 16802
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11
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Wong JWC, Ogbonnaya UO. Biochar porosity: a nature-based dependent parameter to deliver microorganisms to soils for land restoration. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:46894-46909. [PMID: 34263396 DOI: 10.1007/s11356-021-14803-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 05/14/2020] [Indexed: 06/13/2023]
Abstract
Literature shows that biochar can potentially retain nutrients in agricultural soils, avoiding significant nutrient losses. Furthermore, biochar porosity and functional groups have been shown to enhance physico-chemical properties of soil when amended, which in turn has the ability to encourage inhabitation of specific microorganisms as biofertilizers or to enhance soil remediation. It supports scale-dependent parameters and provides both ecosystem services and soil-vegetation solutions relevant to nature-based solutions. However, detailed researches on the mechanisms of soil microbial interactions with biochar porous properties are required, along with the microbial attachment factors, sustenance, and detachment when applied to soils. Recent valuable works have impregnated plant growth-promoting bacteria unto biochar and have observed inconsistent results. Firstly, biochar intrinsic properties alter the fate of impregnation by inhibiting quorum sensing signals, and the macropore requirements for adsorption and/or biofilm formation have not been well considered. Additionally, the nutrient and supplement requirements for each microorganism as well as the adsorption capacity have not been well understood for biochar surfaces. Substantial information is required to understand the mechanisms of microbe adsorption and factors that influence the process, as well as sustenance of the matrix even when deployed in soils. Research directions should focus on determining molecular and chemical mechanisms responsible for the biochar-microbe interaction process and fate of microbe on biochar while expressing plant growth-promoting properties, which needs to be done in laboratory and field trials. Graphical abstract.
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Affiliation(s)
- Jonathan W C Wong
- Institute of Bioresource and Agriculture and the Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong
| | - Uchenna O Ogbonnaya
- Institute of Bioresource and Agriculture and the Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong.
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12
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Xuan TF, Wang ZQ, Liu J, Yu HT, Lin QW, Chen WM, Lin J. Design and Synthesis of Novel c-di-GMP G-Quadruplex Inducers as Bacterial Biofilm Inhibitors. J Med Chem 2021; 64:11074-11089. [PMID: 34323486 DOI: 10.1021/acs.jmedchem.1c00465] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The formation of biofilms by clinical pathogens typically leads to chronic and recurring antibiotic-resistant infections. High cellular levels of cyclic diguanylate (c-di-GMP), a ubiquitous secondary messenger of bacteria, have been proven to be associated with a sessile biofilm lifestyle of pathogens. A promising antibiofilm strategy involving the induction of c-di-GMP to form dysfunctional G-quadruplexes, thereby blocking the c-di-GMP-mediated biofilm regulatory pathway, was proposed in this study. In this new strategy, a series of novel c-di-GMP G-quadruplex inducers were designed and synthesized for development of therapeutic biofilm inhibitors. Compound 5h exhibited favorable c-di-GMP G-quadruplex-inducing activity and 62.18 ± 6.76% biofilm inhibitory activity at 1.25 μM without any DNA intercalation effect. Moreover, the favorable performance of 5h in interfering with c-di-GMP-related biological functions, including bacterial motility and bacterial extracellular polysaccharide secretion, combined with the reporter strain and transcriptome analysis results confirmed the c-di-GMP signaling-related action mechanism of 5h.
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Affiliation(s)
- Teng-Fei Xuan
- College of Pharmacy, Jinan University, Guangzhou 510632, P. R. China
| | - Zi-Qiang Wang
- College of Pharmacy, Jinan University, Guangzhou 510632, P. R. China
| | - Jun Liu
- College of Pharmacy, Jinan University, Guangzhou 510632, P. R. China
| | - Hai-Tao Yu
- College of Pharmacy, Jinan University, Guangzhou 510632, P. R. China
| | - Qian-Wen Lin
- College of Pharmacy, Jinan University, Guangzhou 510632, P. R. China
| | - Wei-Min Chen
- College of Pharmacy, Jinan University, Guangzhou 510632, P. R. China
| | - Jing Lin
- College of Pharmacy, Jinan University, Guangzhou 510632, P. R. China
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13
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Sharma D, Sharma A, Singh B, Verma SK. Pan-proteome profiling of emerging and re-emerging zoonotic pathogen Orientia tsutsugamushi for getting insight into microbial pathogenesis. Microb Pathog 2021; 158:105103. [PMID: 34298125 DOI: 10.1016/j.micpath.2021.105103] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Revised: 07/13/2021] [Accepted: 07/16/2021] [Indexed: 01/21/2023]
Abstract
With the occurrence and evolution of antibiotic and multidrug resistance in bacteria most of the existing remedies are becoming ineffective. The pan-proteome exploration of the bacterial pathogens helps to identify the wide spectrum therapeutic targets which will be effective against all strains in a species. The current study is focused on the pan-proteome profiling of zoonotic pathogen Orientia tsutsugamushi (Ott) for the identification of potential therapeutic targets. The pan-proteome of Ott is estimated to be extensive in nature that has 1429 protein clusters, out of which 694 were core, 391 were accessory, and 344 were unique. It was revealed that 622 proteins were essential, 222 proteins were virulent factors, and 42 proteins were involved in antibiotic resistance. The potential therapeutic targets were further classified into eleven broad classes among which gene expression and regulation, transport, and metabolism were dominant. The biological interactome analysis of therapeutic targets revealed that an ample amount of interactions were present among the proteins involved in DNA replication, ribosome assembly, cellwall metabolism, cell division, and antimicrobial resistance. The predicted therapeutic targets from the pan-proteome of Ott are involved in various biological processes, virulence, and antibiotic resistance; hence envisioned as potential candidates for drug discovery to combat scrub typhus.
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Affiliation(s)
- Dixit Sharma
- Centre for Computational Biology and Bioinformatics, School of Life Sciences, Central University of Himachal Pradesh, Kangra, Himachal Pradesh, 176206, India.
| | - Ankita Sharma
- Centre for Computational Biology and Bioinformatics, School of Life Sciences, Central University of Himachal Pradesh, Kangra, Himachal Pradesh, 176206, India
| | - Birbal Singh
- ICAR-Indian Veterinary Research Institute, Regional Station, Palampur, Himachal Pradesh, 176061, India
| | - Shailender Kumar Verma
- Centre for Computational Biology and Bioinformatics, School of Life Sciences, Central University of Himachal Pradesh, Kangra, Himachal Pradesh, 176206, India
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14
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Cordova A, Ritchie C, Böhnert V, Li L. Human SLC46A2 Is the Dominant cGAMP Importer in Extracellular cGAMP-Sensing Macrophages and Monocytes. ACS CENTRAL SCIENCE 2021; 7:1073-1088. [PMID: 34235268 PMCID: PMC8228594 DOI: 10.1021/acscentsci.1c00440] [Citation(s) in RCA: 68] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Indexed: 05/04/2023]
Abstract
Administration of exogenous CDNs to activate the cGAMP-STING pathway is a promising therapeutic strategy to unleash the full potential of cancer immunotherapy. This strategy mirrors the role of endogenous extracellular cGAMP, an immunotransmitter that is transferred from cancer cells to cGAMP-sensing cells in the host, promoting immunity. However, the CDN import mechanisms used by host cells within tumors remain unknown. Here we identified the protein SLC46A2 as the dominant cGAMP importer in primary human monocytes. Furthermore, we discovered that monocytes and M1-polarized macrophages directly sense tumor-derived extracellular cGAMP in murine tumors. Finally, we demonstrated that SLC46A2 is the dominant cGAMP importer in monocyte-derived macrophages. Together, we provide the first cellular and molecular mechanisms of cGAMP as an immunotransmitter, paving the way for effective STING pathway therapeutics.
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Affiliation(s)
- Anthony
F. Cordova
- Department of Biochemistry and Institute of Chemistry, Engineering, and Medicine
for Human Health (ChEM-H), Stanford University, Stanford, California 94305, United States
| | - Christopher Ritchie
- Department of Biochemistry and Institute of Chemistry, Engineering, and Medicine
for Human Health (ChEM-H), Stanford University, Stanford, California 94305, United States
| | - Volker Böhnert
- Department of Biochemistry and Institute of Chemistry, Engineering, and Medicine
for Human Health (ChEM-H), Stanford University, Stanford, California 94305, United States
| | - Lingyin Li
- Department of Biochemistry and Institute of Chemistry, Engineering, and Medicine
for Human Health (ChEM-H), Stanford University, Stanford, California 94305, United States
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15
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Fernández-Llamosas H, Díaz E, Carmona M. Motility, Adhesion and c-di-GMP Influence the Endophytic Colonization of Rice by Azoarcus sp. CIB. Microorganisms 2021; 9:microorganisms9030554. [PMID: 33800326 PMCID: PMC7998248 DOI: 10.3390/microorganisms9030554] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 02/18/2021] [Accepted: 03/05/2021] [Indexed: 01/26/2023] Open
Abstract
Proficient crop production is needed to ensure the feeding of a growing global population. The association of bacteria with plants plays an important role in the health state of the plants contributing to the increase of agricultural production. Endophytic bacteria are ubiquitous in most plant species providing, in most cases, plant promotion properties. However, the knowledge on the genetic determinants involved in the colonization of plants by endophytic bacteria is still poorly understood. In this work we have used a genetic approach based on the construction of fliM, pilX and eps knockout mutants to show that the motility mediated by a functional flagellum and the pili type IV, and the adhesion modulated by exopolysaccarides are required for the efficient colonization of rice roots by the endophyte Azoarcus sp. CIB. Moreover, we have demonstrated that expression of an exogenous diguanylate cyclase or phophodiesterase, which causes either an increase or decrease of the intracellular levels of the second messenger cyclic di-GMP (c-di-GMP), respectively, leads to a reduction of the ability of Azoarcus sp. CIB to colonize rice plants. Here we present results demonstrating the unprecedented role of the universal second messenger cyclic-di-GMP in plant colonization by an endophytic bacterium, Azoarcus sp. CIB. These studies pave the way to further strategies to modulate the interaction of endophytes with their target plant hosts.
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16
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Nitrate Is an Environmental Cue in the Gut for Salmonella enterica Serovar Typhimurium Biofilm Dispersal through Curli Repression and Flagellum Activation via Cyclic-di-GMP Signaling. mBio 2021; 13:e0288621. [PMID: 35130730 PMCID: PMC8822344 DOI: 10.1128/mbio.02886-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Curli, a major component of the bacterial biofilms in the intestinal tract, activates pattern recognition receptors and triggers joint inflammation after infection with Salmonella enterica serovar Typhimurium. The factors that allow S. Typhimurium to disperse from biofilms and invade the epithelium to establish a successful infection during acute inflammation remain unknown. Here, we studied S. Typhimurium biofilms in vitro and in vivo to understand how the inflammatory environment regulates the switch between multicellular and motile S. Typhimurium in the gut. We discovered that nitrate generated by the host is an environmental cue that induces S. Typhimurium to disperse from the biofilm. Nitrate represses production of an important biofilm component, curli, and activates flagella via the modulation of intracellular cyclic-di-GMP levels. We conclude that nitrate plays a central role in pathogen fitness by regulating the sessile-to-motile lifestyle switch during infection. IMPORTANCE Recent studies provided important insight into our understanding of the role of c-di-GMP signaling and the regulation of enteric biofilms. Despite an improved understanding of how c-di-GMP signaling regulates S. Typhimurium biofilms, the processes that affect the intracellular c-di-GMP levels and the formation of multicellular communities in vivo during infections remain unknown. Here, we show that nitrate generated in the intestinal lumen during infection with S. Typhimurium is an important regulator of biofilm formation in vivo.
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17
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Cavagnero KJ, Badrani JH, Naji LH, Amadeo MB, Leng AS, Lacasa LD, Strohm AN, Renusch SR, Gasparian SS, Doherty TA. Cyclic-di-GMP Induces STING-Dependent ILC2 to ILC1 Shift During Innate Type 2 Lung Inflammation. Front Immunol 2021; 12:618807. [PMID: 33679760 PMCID: PMC7935536 DOI: 10.3389/fimmu.2021.618807] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Accepted: 01/25/2021] [Indexed: 12/18/2022] Open
Abstract
Type 2 inflammation is found in most forms of asthma, which may co-exist with recurrent viral infections, bacterial colonization, and host cell death. These processes drive the accumulation of intracellular cyclic-di-nucleotides such as cyclic-di-GMP (CDG). Group 2 innate lymphoid cells (ILC2s) are critical drivers of type 2 lung inflammation during fungal allergen exposure in mice; however, it is unclear how CDG regulates lung ILC responses during lung inflammation. Here, we show that intranasal CDG induced early airway type 1 interferon (IFN) production and dramatically suppressed CD127+ST2+ ILC2s and type 2 lung inflammation during Alternaria and IL-33 exposure. Further, CD127-ST2-Thy1.2+ lung ILCs, which showed a transcriptomic signature consistent with ILC1s, were expanded and activated by CDG combined with either Alternaria or IL-33. CDG-mediated suppression of type 2 inflammation occurred independent of IL-18R, IL-12, and STAT6 but required the stimulator of interferon genes (STING) and type 1 IFN signaling. Thus, CDG potently suppresses ILC2-driven lung inflammation and promotes ILC1 responses. These results suggest potential therapeutic modulation of STING to suppress type 2 inflammation and/or increase anti-viral responses during respiratory infections.
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Affiliation(s)
- Kellen J. Cavagnero
- Department of Medicine, University of California, San Diego, La Jolla, CA, United States
- Department of Dermatology, University of California, San Diego, La Jolla, CA, United States
| | - Jana H. Badrani
- Department of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Luay H. Naji
- Department of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Michael B. Amadeo
- Department of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Anthea S. Leng
- Department of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Lee Diego Lacasa
- Department of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Allyssa N. Strohm
- Department of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Samantha R. Renusch
- Department of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Suzanna S. Gasparian
- Department of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Taylor A. Doherty
- Department of Medicine, University of California, San Diego, La Jolla, CA, United States
- Veterans Affairs San Diego Health Care System, La Jolla, CA, United States
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18
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Khan F, Tabassum N, Pham DTN, Oloketuyi SF, Kim YM. Molecules involved in motility regulation in Escherichia coli cells: a review. BIOFOULING 2020; 36:889-908. [PMID: 33028083 DOI: 10.1080/08927014.2020.1826939] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 09/14/2020] [Accepted: 09/15/2020] [Indexed: 06/11/2023]
Abstract
The initial colonization of the host organism by commensal, probiotic, and pathogenic Escherichia coli strains is an important step in the development of infections and biofilms. Sensing and colonization of host cell surfaces are governed by flagellar and fimbriae/pili appendages, respectively. Biofilm formation confers great advantages on pathogenic E. coli cells such as protection against the host immune system, antimicrobial agents, and several environmental stress factors. The transition from planktonic to sessile physiological states involves several signaling cascades and factors responsible for the regulation of flagellar motility in E. coli cells. These regulatory factors have thus become important targets to control pathogenicity. Hence, attenuation of flagellar motility is considered a potential therapy against pathogenic E. coli. The present review describes signaling pathways and proteins involved in direct or indirect regulation of flagellar motility. Furthermore, application strategies for antimotility natural or synthetic compounds are discussed also.
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Affiliation(s)
- Fazlurrahman Khan
- Institute of Food Science, Pukyong National University, Busan, Republic of Korea
| | - Nazia Tabassum
- Industrial Convergence Bionix Engineering, Pukyong National University, Busan, Republic of Korea
| | - Dung Thuy Nguyen Pham
- Department of Food Science and Technology, Pukyong National University, Busan, Republic of Korea
| | | | - Young-Mog Kim
- Institute of Food Science, Pukyong National University, Busan, Republic of Korea
- Department of Food Science and Technology, Pukyong National University, Busan, Republic of Korea
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19
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De Vrieze M, Varadarajan AR, Schneeberger K, Bailly A, Rohr RP, Ahrens CH, Weisskopf L. Linking Comparative Genomics of Nine Potato-Associated Pseudomonas Isolates With Their Differing Biocontrol Potential Against Late Blight. Front Microbiol 2020; 11:857. [PMID: 32425922 PMCID: PMC7204214 DOI: 10.3389/fmicb.2020.00857] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 04/09/2020] [Indexed: 01/22/2023] Open
Abstract
For plants, the advantages of associating with beneficial bacteria include plant growth promotion, reduction of abiotic and biotic stresses and enhanced protection against various pests and diseases. Beneficial bacteria rightly equipped for successful plant colonization and showing antagonistic activity toward plant pathogens seem to be actively recruited by plants. To gain more insights into the genetic determinants responsible for plant colonization and antagonistic activities, we first sequenced and de novo assembled the complete genomes of nine Pseudomonas strains that had exhibited varying antagonistic potential against the notorious oomycete Phytophthora infestans, placed them into the phylogenomic context of known Pseudomonas biocontrol strains and carried out a comparative genomic analysis to define core, accessory (i.e., genes found in two or more, but not all strains) and unique genes. Next, we assessed the colonizing abilities of these strains and used bioassays to characterize their inhibitory effects against different stages of P. infestans' lifecycle. The phenotype data were then correlated with genotype information, assessing over three hundred genes encoding known factors for plant colonization and antimicrobial activity as well as secondary metabolite biosynthesis clusters predicted by antiSMASH. All strains harbored genes required for successful plant colonization but also distinct arsenals of antimicrobial compounds. We identified genes coding for phenazine, hydrogen cyanide, 2-hexyl, 5-propyl resorcinol and pyrrolnitrin synthesis, as well as various siderophores, pyocins and type VI secretion systems. Additionally, the comparative genomic analysis revealed about a hundred accessory genes putatively involved in anti-Phytophthora activity, including a type II secretion system (T2SS), several peptidases and a toxin. Transcriptomic studies and mutagenesis are needed to further investigate the putative involvement of the novel candidate genes and to identify the various mechanisms involved in the inhibition of P. infestans by different Pseudomonas strains.
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Affiliation(s)
- Mout De Vrieze
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Adithi R. Varadarajan
- Agroscope, Research Group Molecular Diagnostics, Genomics and Bioinformatics & SIB Swiss Institute of Bioinformatics, Wädenswil, Switzerland
| | - Kerstin Schneeberger
- Agroscope, Research Group Molecular Diagnostics, Genomics and Bioinformatics & SIB Swiss Institute of Bioinformatics, Wädenswil, Switzerland
| | - Aurélien Bailly
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Rudolf P. Rohr
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Christian H. Ahrens
- Agroscope, Research Group Molecular Diagnostics, Genomics and Bioinformatics & SIB Swiss Institute of Bioinformatics, Wädenswil, Switzerland
| | - Laure Weisskopf
- Department of Biology, University of Fribourg, Fribourg, Switzerland
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20
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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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21
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Sharma D, Sharma A, Singh B, Verma SK. Bioinformatic Exploration of Metal-Binding Proteome of Zoonotic Pathogen Orientia tsutsugamushi. Front Genet 2019; 10:797. [PMID: 31608099 PMCID: PMC6769048 DOI: 10.3389/fgene.2019.00797] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 07/30/2019] [Indexed: 12/21/2022] Open
Abstract
Metal ions are involved in many essential biological processes and are crucial for the survival of all organisms. Identification of metal-binding proteins (MBPs) of human affecting pathogens may provide the blueprint for understanding biological metal usage and their putative roles in pathogenesis. This study is focused on the analysis of MBPs from Orientia tsutsugamushi (Ott), a causal agent of scrub typhus in humans. A total of 321 proteins were predicted as putative MBPs, based on sequence search and three-dimensional structure analysis. Majority of proteins could bind with magnesium, and the order of metal binding was Mg > Ca > Zn > Mn > Fe > Cd > Ni > Co > Cu, respectively. The predicted MBPs were functionally classified into nine broad classes. Among them, gene expression and regulation, metabolism, cell signaling, and transport classes were dominant. It was noted that the putative MBPs were localized in all subcellular compartments of Ott, but majorly found in the cytoplasm. Additionally, it was revealed that out of 321 predicted MBPs 245 proteins were putative bacterial toxins and among them, 98 proteins were nonhomologous to human proteome. Sixty putative MBPs showed the ability to interact with drug or drug-like molecules, which indicate that they may be used as broad-spectrum drug targets. These predicted MBPs from Ott could play vital role(s) in various cellular activities and virulence, hence may serve as plausible therapeutic targets to design metal-based drugs to curtail its infection.
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Affiliation(s)
- Dixit Sharma
- Centre for Computational Biology and Bioinformatics, School of Life Sciences, Central University of Himachal Pradesh, Kangra, India
| | - Ankita Sharma
- Centre for Computational Biology and Bioinformatics, School of Life Sciences, Central University of Himachal Pradesh, Kangra, India
| | - Birbal Singh
- ICAR-Indian Veterinary Research Institute, Regional Station, Palampur, India
| | - Shailender Kumar Verma
- Centre for Computational Biology and Bioinformatics, School of Life Sciences, Central University of Himachal Pradesh, Kangra, India
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22
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Li W, Hu L, Xie Z, Xu H, Li M, Cui T, He ZG. Cyclic di-GMP integrates functionally divergent transcription factors into a regulation pathway for antioxidant defense. Nucleic Acids Res 2019; 46:7270-7283. [PMID: 29982829 PMCID: PMC6101608 DOI: 10.1093/nar/gky611] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 06/27/2018] [Indexed: 11/14/2022] Open
Abstract
Cyclic diguanylate monophosphate (c-di-GMP) is a global signaling molecule that modulates diverse cellular processes through its downstream receptors. However, no study has fully clarified the mechanisms by which c-di-GMP organizes functionally divergent regulators to drive the gene expression for coping with environmental stress. Here, we reported that c-di-GMP can integrate two functionally opposite receptor transcription factors, namely, LtmA and HpoR, into a pathway to regulate the antioxidant processes in Mycobacterium smegmatis. In contrast to HpoR, LtmA is an activator that positively regulates the expression of redox gene clusters and the mycobacterial H2O2 resistance. LtmA can physically interact with HpoR. A high level of c-di-GMP stimulates the positive regulation of LtmA and boosts the physical interaction between the two regulators, further enhancing the DNA-binding ability of LtmA and reducing the inhibitory activity of HpoR. Therefore, upon exposure to oxidative stress, c-di-GMP can orchestrate functionally divergent transcription factors to trigger antioxidant defense in mycobacteria. This finding presents a noteworthy example of how a bacterium remodels its transcriptional network via c-di-GMP in response to environmental stress.
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Affiliation(s)
- Weihui Li
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Lihua Hu
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Zhiwei Xie
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Hui Xu
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Meng Li
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Tao Cui
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Zheng-Guo He
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
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23
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Jiang BL, Jiang GF, Liu W, Yang LC, Yang LY, Wang L, Hang XH, Tang JL. RpfC regulates the expression of the key regulator hrpX of the hrp/T3SS system in Xanthomonas campestris pv. campestris. BMC Microbiol 2018; 18:103. [PMID: 30176800 PMCID: PMC6122198 DOI: 10.1186/s12866-018-1233-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Accepted: 08/15/2018] [Indexed: 12/02/2022] Open
Abstract
Background The Gram-negative phytopathogenic bacterium Xanthomonas campestris pv. campestris recruits the hrp/T3SS system to inject pathogenicity effector proteins into host cells and uses the rpf/DSF cell-cell signaling system to regulate the expression of virulence factors such as extracellular enzymes and polysaccharide. Whether these two systems have any connection is unknown. Methods Positive regulator candidates affecting hrpX expression were identified by sacB strategy. The transcriptional expression was determined by qRT-PCR and GUS activity analysis. Transcriptome analysis was performed by RNA deep-sequencing. The hypersensitive response (HR) was determined in the nonhost plant pepper ECW-10R and electrolyte leakage assay. Results Mutation of the gene encoding the sensor RpfC of the rpf/DSF system significantly reduced the expression of hrpX, the key regulator of the hrp/T3SS system, all of the genes in the hrp cluster and most reported type III effector genes. Mutation of rpfG did not affect the expression of hrpX. The rpfC mutant showed a delayed and weakened HR induction. Conclusions RpfC positively regulates the expression of hrpX independent of RpfG, showing a complex regulatory network linking the rpf/DSF and hrp/T3SS systems. Electronic supplementary material The online version of this article (10.1186/s12866-018-1233-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Bo-Le Jiang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, 530004, Guangxi, China
| | - Guo-Feng Jiang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, 530004, Guangxi, China
| | - Wei Liu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, 530004, Guangxi, China
| | - Li-Chao Yang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, 530004, Guangxi, China
| | - Li-Yan Yang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, 530004, Guangxi, China
| | - Lin Wang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, 530004, Guangxi, China
| | - Xiao-Hong Hang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, 530004, Guangxi, China
| | - Ji-Liang Tang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, 530004, Guangxi, China.
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24
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Bharati BK, Mukherjee R, Chatterji D. Substrate-induced domain movement in a bifunctional protein, DcpA, regulates cyclic di-GMP turnover: Functional implications of a highly conserved motif. J Biol Chem 2018; 293:14065-14079. [PMID: 29980599 DOI: 10.1074/jbc.ra118.003917] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 06/26/2018] [Indexed: 11/06/2022] Open
Abstract
In eubacteria, cyclic di-GMP (c-di-GMP) signaling is involved in virulence, persistence, motility and generally orchestrates multicellular behavior in bacterial biofilms. Intracellular c-di-GMP levels are maintained by the opposing activities of diguanylate cyclases (DGCs) and cognate phosphodiesterases (PDEs). The c-di-GMP homeostasis in Mycobacterium smegmatis is supported by DcpA, a conserved, bifunctional protein with both DGC and PDE activities. DcpA is a multidomain protein whose GAF-GGDEF-EAL domains are arranged in tandem and are required for these two activities. To gain insight into how interactions among these three domains affect DcpA activity, here we studied its domain dynamics using real-time FRET. We demonstrate that substrate binding in DcpA results in domain movement that prompts a switch from an "open" to a "closed" conformation and alters its catalytic activity. We found that a single point mutation in the conserved EAL motif (E384A) results in complete loss of the PDE activity of the EAL domain and in a significant decrease in the DGC activity of the GGDEF domain. Structural analyses revealed multiple hydrophobic and aromatic residues around Cys579 that are necessary for proper DcpA folding and maintenance of the active conformation. On the basis of these observations and taking into account additional bioinformatics analysis of EAL domain-containing proteins, we identified a critical putatively conserved motif, GCXXXQGF, that plays an important role in c-di-GMP turnover. We conclude that a substrate-induced conformational switch involving movement of a loop containing a conserved motif in the bifunctional diguanylate cyclase-phosphodiesterase DcpA controls c-di-GMP turnover in M. smegmatis.
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Affiliation(s)
- Binod K Bharati
- From the Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India and
| | - Raju Mukherjee
- Department of Biology, Indian Institute of Science Education and Research, Tirupati 517507, India
| | - Dipankar Chatterji
- From the Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India and
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Bagheri M, Mirbagheri SA. Critical review of fouling mitigation strategies in membrane bioreactors treating water and wastewater. BIORESOURCE TECHNOLOGY 2018; 258:318-334. [PMID: 29548641 DOI: 10.1016/j.biortech.2018.03.026] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Revised: 03/02/2018] [Accepted: 03/05/2018] [Indexed: 05/24/2023]
Abstract
The current research was an effort to critically review all approaches used for membrane fouling control in the membrane bioreactors treating water and wastewater. The first generation of antifouling methods tried to optimize operational conditions, or used chemical agents to control membrane fouling. Despite their positive impacts on the fouling mitigation, these methods did not provide a sustainable solution for the problem. Moreover, chemical agents may affect microorganisms in bioreactors and has some environmental drawbacks. The improved knowledge of membrane fouling mechanism and effective factors has directed the attention of researchers to novel methods that focus on disrupting fouling mechanism through affecting fouling causing bacteria. Employing nanomaterials, cell entrapment, biologically- and electrically-based methods are the latest efforts. The results of this review indicate that sustainable control of membrane fouling requires employing more than one single approach. Large scale application of fouling mitigation strategies should be the focus of future studies.
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Affiliation(s)
- Majid Bagheri
- Civil, Architectural and Environmental Engineering Department, Missouri University of Science and Technology, Rolla, MO, United States.
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Laventie BJ, Glatter T, Jenal U. Pull-Down with a c-di-GMP-Specific Capture Compound Coupled to Mass Spectrometry as a Powerful Tool to Identify Novel Effector Proteins. Methods Mol Biol 2018; 1657:361-376. [PMID: 28889308 DOI: 10.1007/978-1-4939-7240-1_28] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Capture compound technology coupled to mass spectrometry (CCMS) allows to biochemically identify ligand receptors. Using a c-di-GMP-specific Capture Compound, we adapted this method for the identification and characterization of c-di-GMP binding proteins in any bacterial species. Because in silico analysis often fails to predict novel c-di-GMP effectors, this universal method aims at better defining the cellular c-di-GMP network in a wide range of bacteria. CCMS was successfully applied in several bacterial species (Nesper et al., J Proteom 75:4874-4878, 2012; Steiner et al., EMBO J 32:354-368, 2013; Tschowri et al., Cell 158:1136-1147, 2014; Trampari et al., J Biol Chem 290:24470-24483, 2015; Rotem et al., J Bacteriol 198:127-137, 2015). To outline the detailed protocol and to illustrate its power, we use Pseudomonas aeruginosa, an opportunistic pathogen in which c-di-GMP plays a critical role in virulence and biofilm control, as an example. CCMS identified 74% (38/51) of the known or predicted components of the c-di-GMP network.
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Affiliation(s)
| | - Timo Glatter
- Proteomics Core Facility, Biozentrum, University of Basel, Basel, Switzerland
- Facility for Mass Spectrometry and Proteomics, Max-Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Urs Jenal
- Infection Biology, Biozentrum, University of Basel, Basel, Switzerland
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Li W, Li M, Hu L, Zhu J, Xie Z, Chen J, He ZG. HpoR, a novel c-di-GMP effective transcription factor, links the second messenger's regulatory function to the mycobacterial antioxidant defense. Nucleic Acids Res 2018; 46:3595-3611. [PMID: 29490073 PMCID: PMC5909442 DOI: 10.1093/nar/gky146] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2017] [Revised: 02/13/2018] [Accepted: 02/16/2018] [Indexed: 01/06/2023] Open
Abstract
Cyclic di-GMP (c-di-GMP) is a global signaling molecule that widely modulates diverse cellular processes. However, whether or not the c-di-GMP signal participates in regulation of bacterial antioxidant defense is unclear, and the involved regulators remain to be explored. In this study, we characterized HpoR as a novel c-di-GMP effective transcription factor and found a link between the c-di-GMP signal and the antioxidant regulation in Mycobacterium smegmatis. H2O2 stress induces c-di-GMP accumulation in M. smegmatis. High level of c-di-GMP triggers expression of a redox gene cluster, designated as hpoR operon, which is required for the mycobacterial H2O2 resistance. HpoR acts as an inhibitor of the hpoR operon and recognizes a 12-bp motif sequence within the upstream regulatory region of the operon. c-di-GMP specifically binds with HpoR at a ratio of 1:1. Low concentrations of c-di-GMP stimulate the DNA-binding activity of HpoR, whereas high concentrations of the signal molecule inhibit the activity. Strikingly, high level of c-di-GMP de-represses the intracellular association of HpoR with the regulatory region of the hpoR operon in M. smegmatis and enhances the mycobacterial H2O2 resistance. Therefore, we report a novel c-di-GMP effective regulator in mycobacteria, which extends the second messenger's function to bacterial antioxidant defense.
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Affiliation(s)
- Weihui Li
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Meng Li
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Lihua Hu
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Jingpeng Zhu
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Zhiwei Xie
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Jiarui Chen
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Zheng-Guo He
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
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Hengge R. Trigger phosphodiesterases as a novel class of c-di-GMP effector proteins. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0498. [PMID: 27672149 PMCID: PMC5052742 DOI: 10.1098/rstb.2015.0498] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/14/2016] [Indexed: 11/28/2022] Open
Abstract
The bacterial second messenger c-di-GMP controls bacterial biofilm formation, motility, cell cycle progression, development and virulence. It is synthesized by diguanylate cyclases (with GGDEF domains), degraded by specific phosphodiesterases (PDEs, with EAL of HD-GYP domains) and sensed by a wide variety of c-di-GMP-binding effectors that control diverse targets. c-di-GMP-binding effectors can be riboswitches as well as proteins with highly diverse structures and functions. The latter include ‘degenerate’ GGDEF/EAL domain proteins that are enzymatically inactive but still able to bind c-di-GMP. Surprisingly, two enzymatically active ‘trigger PDEs’, the Escherichia coli proteins PdeR and PdeL, have recently been added to this list of c-di-GMP-sensing effectors. Mechanistically, trigger PDEs are multifunctional. They directly and specifically interact with a macromolecular target (e.g. with a transcription factor or directly with a promoter region), whose activity they control by their binding and degradation of c-di-GMP—their PDE activity thus represents the c-di-GMP sensor or effector function. In this process, c-di-GMP serves as a regulatory ligand, but in contrast to classical allosteric control, this ligand is also degraded. The resulting kinetics and circuitry of control are ideally suited for trigger PDEs to serve as key components in regulatory switches. This article is part of the themed issue ‘The new bacteriology’.
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Affiliation(s)
- Regine Hengge
- Institute of Biology/Microbiology, Humboldt-Universität zu Berlin, 10115 Berlin, Germany
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29
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Rossello J, Lima A, Gil M, Rodríguez Duarte J, Correa A, Carvalho PC, Kierbel A, Durán R. The EAL-domain protein FcsR regulates flagella, chemotaxis and type III secretion system in Pseudomonas aeruginosa by a phosphodiesterase independent mechanism. Sci Rep 2017; 7:10281. [PMID: 28860517 PMCID: PMC5579053 DOI: 10.1038/s41598-017-09926-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 08/02/2017] [Indexed: 11/18/2022] Open
Abstract
The second messenger c-di-GMP regulates the switch between motile and sessile bacterial lifestyles. A general feature of c-di-GMP metabolism is the presence of a surprisingly large number of genes coding for diguanylate cyclases and phosphodiesterases, the enzymes responsible for its synthesis and degradation respectively. However, the physiological relevance of this apparent redundancy is not clear, emphasizing the need for investigating the functions of each of these enzymes. Here we focused on the phosphodiesterase PA2133 from Pseudomonas aeruginosa, an important opportunistic pathogen. We phenotypically characterized P. aeruginosa strain K overexpressing PA2133 or its inactive mutant. We showed that biofilm formation and motility are severely impaired by overexpression of PA2133. Our quantitative proteomic approach applied to the membrane and exoprotein fractions revealed that proteins involved in three processes were mostly affected: flagellar motility, type III secretion system and chemotaxis. While inhibition of biofilm formation can be ascribed to the phosphodiesterase activity of PA2133, down-regulation of flagellar, chemotaxis, and type III secretion system proteins is independent of this enzymatic activity. Based on these unexpected effects of PA2133, we propose to rename this gene product FcsR, for Flagellar, chemotaxis and type III secretion system Regulator.
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Affiliation(s)
- Jessica Rossello
- Analytical Biochemistry and Proteomics Unit, Institut Pasteur de Montevideo/Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
| | - Analía Lima
- Analytical Biochemistry and Proteomics Unit, Institut Pasteur de Montevideo/Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
| | - Magdalena Gil
- Analytical Biochemistry and Proteomics Unit, Institut Pasteur de Montevideo/Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay.,Unit of Dynamics of Host-Pathogen Interactions, Institut Pasteur, Paris, France
| | - Jorge Rodríguez Duarte
- Analytical Biochemistry and Proteomics Unit, Institut Pasteur de Montevideo/Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
| | - Agustín Correa
- Unidad de Proteínas Recombinantes, Institut Pasteur de Montevideo, Montevideo, Uruguay
| | - Paulo C Carvalho
- Laboratory for Proteomics and Protein Engineering, Carlos Chagas Institute, Fiocruz-Paraná, Curitiba, Brazil
| | - Arlinet Kierbel
- Instituto de Investigaciones Biotecnológicas Dr. Rodolfo A. Ugalde (IIB-INTECH), Universidad Nacional de San Martín, Consejo Nacional de Investigaciones Científicas y Técnicas (UNSAM-CONICET), San Martín, Buenos Aires, Argentina
| | - Rosario Durán
- Analytical Biochemistry and Proteomics Unit, Institut Pasteur de Montevideo/Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay.
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A Nutrient-Regulated Cyclic Diguanylate Phosphodiesterase Controls Clostridium difficile Biofilm and Toxin Production during Stationary Phase. Infect Immun 2017; 85:IAI.00347-17. [PMID: 28652311 DOI: 10.1128/iai.00347-17] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 06/20/2017] [Indexed: 12/18/2022] Open
Abstract
The signaling molecule cyclic diguanylate (c-di-GMP) mediates physiological adaptation to extracellular stimuli in a wide range of bacteria. The complex metabolic pathways governing c-di-GMP synthesis and degradation are highly regulated, but the specific cues that impact c-di-GMP signaling are largely unknown. In the intestinal pathogen Clostridium difficile, c-di-GMP inhibits flagellar motility and toxin production and promotes pilus-dependent biofilm formation, but no specific biological functions have been ascribed to any of the individual c-di-GMP synthases or phosphodiesterases (PDEs). Here, we report the functional and biochemical characterization of a c-di-GMP PDE, PdcA, 1 of 37 confirmed or putative c-di-GMP metabolism proteins in C. difficile 630. Our studies reveal that pdcA transcription is controlled by the nutrient-regulated transcriptional regulator CodY and accordingly increases during stationary phase. In addition, PdcA PDE activity is allosterically regulated by GTP, further linking c-di-GMP levels to nutrient availability. Mutation of pdcA increased biofilm formation and reduced toxin biosynthesis without affecting swimming motility or global intracellular c-di-GMP. Analysis of the transcriptional response to pdcA mutation indicates that PdcA-dependent phenotypes manifest during stationary phase, consistent with regulation by CodY. These results demonstrate that inactivation of this single PDE gene is sufficient to impact multiple c-di-GMP-dependent phenotypes, including the production of major virulence factors, and suggest a link between c-di-GMP signaling and nutrient availability.
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31
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da Costa Vasconcelos FN, Maciel NK, Favaro DC, de Oliveira LC, Barbosa AS, Salinas RK, de Souza RF, Farah CS, Guzzo CR. Structural and Enzymatic Characterization of a cAMP-Dependent Diguanylate Cyclase from Pathogenic Leptospira Species. J Mol Biol 2017; 429:2337-2352. [PMID: 28601495 DOI: 10.1016/j.jmb.2017.06.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Revised: 06/01/2017] [Accepted: 06/01/2017] [Indexed: 12/23/2022]
Abstract
Leptospira interrogans serovar Copenhageni is a human pathogen that causes leptospirosis, a worldwide zoonosis. The L. interrogans genome codes for a wide array of potential diguanylate cyclase (DGC) enzymes with characteristic GGDEF domains capable of synthesizing the cyclic dinucleotide c-di-GMP, known to regulate transitions between different cellular behavioral states in bacteria. Among such enzymes, LIC13137 (Lcd1), which has an N-terminal cGMP-specific phosphodiesterases, adenylyl cyclases, and FhlA (GAF) domain and a C-terminal GGDEF domain, is notable for having close orthologs present only in pathogenic Leptospira species. Although the function and structure of GGDEF and GAF domains have been studied extensively separately, little is known about enzymes with the GAF-GGDEF architecture. In this report, we address the question of how the GAF domain regulates the DGC activity of Lcd1. The full-length Lcd1 and its GAF domain form dimers in solution. The GAF domain binds specifically cAMP (KD of 0.24μM) and has an important role in the regulation of the DGC activity of the GGDEF domain. Lcd1 DGC activity is negligible in the absence of cAMP and is significantly enhanced in its presence (specific activity of 0.13s-1). The crystal structure of the Lcd1 GAF domain in complex with cAMP provides valuable insights toward explaining its specificity for cAMP and pointing to possible mechanisms by which this cyclic nucleotide regulates the assembly of an active DGC enzyme.
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Affiliation(s)
| | - Nikolas Koshiyama Maciel
- Departamento de Microbiologia, Instituto de Ciências Biomedicas, Universidade de São Paulo, São Paulo, 05508-900, Brazil
| | - Denize Cristina Favaro
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, 05508-900, Brazil; Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, Belo Horizonte, 31270-901, Brazil
| | | | | | - Roberto Kopke Salinas
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, 05508-900, Brazil
| | - Robson Francisco de Souza
- Departamento de Microbiologia, Instituto de Ciências Biomedicas, Universidade de São Paulo, São Paulo, 05508-900, Brazil
| | - Chuck Shaker Farah
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, 05508-900, Brazil
| | - Cristiane Rodrigues Guzzo
- Departamento de Microbiologia, Instituto de Ciências Biomedicas, Universidade de São Paulo, São Paulo, 05508-900, Brazil.
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Xu M, Wang YZ, Yang XA, Jiang T, Xie W. Structural studies of the periplasmic portion of the diguanylate cyclase CdgH from Vibrio cholerae. Sci Rep 2017; 7:1861. [PMID: 28500346 PMCID: PMC5431781 DOI: 10.1038/s41598-017-01989-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 04/06/2017] [Indexed: 01/07/2023] Open
Abstract
Cyclic diguanylate monophosphate (c-di-GMP) is a second messenger involved in bacterial signal transduction and produced by diguanylate cyclases (DGCs) generally containing highly variable periplasmic signal-recognition domains. CdgH is a DGC enzyme that regulates rugosity associated phenotypes in Vibrio cholerae. CdgH has two N-terminal tandem periplasmic substrate-binding (PBPb) domains for its signal recognition; however, the role of the tandem PBPb domains remains unclear. Here, we reported the crystal structure of the periplasmic portion of CdgH, which indicated that both tandem PBPb domains consist of typical interlobe ligand-binding architecture. Unexpectedly, the PBPb-I domain binds an L-arginine which apparently has been co-purified from the E. coli expression system, whereas the PBPb-II domain is in an unliganded open state. Structural comparison with other amino acid-binding proteins indicated that despite similar ligand-binding pockets, the PBPb-I domain possesses two ligand-binding residues (E122 and Y148) not conserved in homologs and involved in hydrophilic and hydrophobic interactions with L-arginine. Isothermal titration calorimetry indicated that the PBPb-I is primarily an L-arginine/L-lysine/L-ornithine-binding domain, whereas the PBPb-II domain exhibits a preference for L-glutamine and L-histidine. Remarkably, we found that the periplasmic portion of CdgH forms a stable dimer in solution and L-arginine binding would cause conformational changes of the dimer.
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Affiliation(s)
- Min Xu
- 0000 0004 1792 5640grid.418856.6National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Yi-Zhi Wang
- 0000 0004 1792 5640grid.418856.6National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China ,0000 0004 1797 8419grid.410726.6University of Chinese Academy of Sciences, Beijing, China
| | - Xiu-An Yang
- 0000 0004 1792 5640grid.418856.6National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Tao Jiang
- 0000 0004 1792 5640grid.418856.6National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China ,0000 0004 1797 8419grid.410726.6University of Chinese Academy of Sciences, Beijing, China
| | - Wei Xie
- 0000 0004 1761 2484grid.33763.32School of Life Sciences, Tianjin University, Tianjin, China
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Activation Mechanism and Cellular Localization of Membrane-Anchored Alginate Polymerase in Pseudomonas aeruginosa. Appl Environ Microbiol 2017; 83:AEM.03499-16. [PMID: 28258142 DOI: 10.1128/aem.03499-16] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Accepted: 02/23/2017] [Indexed: 12/11/2022] Open
Abstract
The exopolysaccharide alginate, produced by the opportunistic human pathogen Pseudomonas aeruginosa, confers a survival advantage to the bacterium by contributing to the formation of characteristic biofilms during infection. Membrane-anchored proteins Alg8 (catalytic subunit) and Alg44 (copolymerase) constitute the alginate polymerase that is being activated by the second messenger molecule bis-(3', 5')-cyclic dimeric GMP (c-di-GMP), but the mechanism of activation remains elusive. To shed light on the c-di-GMP-mediated activation of alginate polymerization in vivo, an in silico structural model of Alg8 fused to the c-di-GMP binding PilZ domain informed by the structure of cellulose synthase, BcsA, was developed. This structural model was probed by site-specific mutagenesis and different cellular levels of c-di-GMP. Results suggested that c-di-GMP-mediated activation of alginate polymerization involves amino acids residing at two loops, including H323 (loop A) and T457 and E460 (loop B), surrounding the catalytic site in the predicted model. The activities of the respective Alg8 variants suggested that c-di-GMP-mediated control of substrate access to the catalytic site of Alg8 is dissimilar to the known activation mechanism of BcsA. Alg8 variants responded differently to various c-di-GMP levels, while MucR imparted c-di-GMP for activation of alginate polymerase. Furthermore, we showed that Alg44 copolymerase constituted a stable dimer, with its periplasmic domains required for protein localization and alginate polymerization and modification. Superfolder green fluorescent protein (GFP) fusions of Alg8 and Alg44 showed a nonuniform, punctate, and patchy arrangement of both proteins surrounding the cell. Overall, this study provides insights into the c-di-GMP-mediated activation of alginate polymerization while assigning functional roles to Alg8 and Alg44, including their subcellular localization and distribution.IMPORTANCE The exopolysaccharide alginate is an important biofilm component of the opportunistic human pathogen P. aeruginosa and the principal cause of the mucoid phenotype that is the hallmark of chronic infections of cystic fibrosis patients. The production of alginate is mediated by interacting membrane proteins Alg8 and Alg44, while their activity is posttranslationally regulated by the second messenger c-di-GMP, a well-known regulator of the synthesis of a range of other exopolysaccharides in bacteria. This study provides new insights into the unknown activation mechanism of alginate polymerization by c-di-GMP. Experimental evidence that the activation of alginate polymerization requires the engagement of specific amino acid residues residing at the catalytic domain of Alg8 glycosyltransferase was obtained, and these residues are proposed to exert an allosteric effect on the PilZAlg44 domain upon c-di-GMP binding. This mechanism is dissimilar to the proposed mechanism of the autoinhibition of cellulose polymerization imposed by salt bridge formation between amino acid residues and released upon c-di-GMP binding, leading to activation of polymerization. On the other hand, conserved amino acid residues in the periplasmic domain of Alg44 were found to be involved in alginate polymerization as well as modification events, i.e., acetylation and epimerization. Due to the critical role of c-di-GMP in the regulation of many biological processes, particularly the motility-sessility switch and also the emergence of persisting mucoid phenotypes, these results aid to reach a better understanding of biofilm-associated regulatory networks and c-di-GMP signaling and might assist the development of inhibitory drugs.
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Sadiq FA, Flint S, Li Y, Liu T, Lei Y, Sakandar HA, He G. New mechanistic insights into the motile-to-sessile switch in various bacteria with particular emphasis on Bacillus subtilis and Pseudomonas aeruginosa: a review. BIOFOULING 2017; 33:306-326. [PMID: 28347177 DOI: 10.1080/08927014.2017.1304541] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 03/04/2017] [Indexed: 06/06/2023]
Abstract
A biofilm is a complex assemblage of microbial communities adhered to a biotic or an abiotic surface which is embedded within a self-produced matrix of extracellular polymeric substances. Many transcriptional regulators play a role in triggering a motile-sessile switch and in consequently producing the biofilm matrix. This review is aimed at highlighting the role of two nucleotide signaling molecules (c-di-GMP and c-di-AMP), toxin antitoxin modules and a novel transcriptional regulator BolA in biofilm formation in various bacteria. In addition, it highlights the common themes that have appeared in recent research regarding the key regulatory components and signal transduction pathways that help Bacillus subtilis and Pseudomonas aeruginosa to acquire the biofilm mode of life.
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Affiliation(s)
- Faizan A Sadiq
- a College of Biosystems Engineering and Food Science , Zhejiang University , Hangzhou , PR China
| | - Steve Flint
- b School of Food and Nutrition , Massey University , Palmerston North , New Zealand
| | - Yun Li
- c School of Life Sciences and Food Technology , Hanshan Normal University , Chaozhou , PR China
| | - TongJie Liu
- a College of Biosystems Engineering and Food Science , Zhejiang University , Hangzhou , PR China
| | - Yuan Lei
- a College of Biosystems Engineering and Food Science , Zhejiang University , Hangzhou , PR China
| | | | - GuoQing He
- a College of Biosystems Engineering and Food Science , Zhejiang University , Hangzhou , PR China
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Moradali MF, Ghods S, Rehm BHA. Pseudomonas aeruginosa Lifestyle: A Paradigm for Adaptation, Survival, and Persistence. Front Cell Infect Microbiol 2017; 7:39. [PMID: 28261568 PMCID: PMC5310132 DOI: 10.3389/fcimb.2017.00039] [Citation(s) in RCA: 784] [Impact Index Per Article: 112.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 02/02/2017] [Indexed: 12/16/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen affecting immunocompromised patients. It is known as the leading cause of morbidity and mortality in cystic fibrosis (CF) patients and as one of the leading causes of nosocomial infections. Due to a range of mechanisms for adaptation, survival and resistance to multiple classes of antibiotics, infections by P. aeruginosa strains can be life-threatening and it is emerging worldwide as public health threat. This review highlights the diversity of mechanisms by which P. aeruginosa promotes its survival and persistence in various environments and particularly at different stages of pathogenesis. We will review the importance and complexity of regulatory networks and genotypic-phenotypic variations known as adaptive radiation by which P. aeruginosa adjusts physiological processes for adaptation and survival in response to environmental cues and stresses. Accordingly, we will review the central regulatory role of quorum sensing and signaling systems by nucleotide-based second messengers resulting in different lifestyles of P. aeruginosa. Furthermore, various regulatory proteins will be discussed which form a plethora of controlling systems acting at transcriptional level for timely expression of genes enabling rapid responses to external stimuli and unfavorable conditions. Antibiotic resistance is a natural trait for P. aeruginosa and multiple mechanisms underlying different forms of antibiotic resistance will be discussed here. The importance of each mechanism in conferring resistance to various antipseudomonal antibiotics and their prevalence in clinical strains will be described. The underlying principles for acquiring resistance leading pan-drug resistant strains will be summarized. A future outlook emphasizes the need for collaborative international multidisciplinary efforts to translate current knowledge into strategies to prevent and treat P. aeruginosa infections while reducing the rate of antibiotic resistance and avoiding the spreading of resistant strains.
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Affiliation(s)
| | | | - Bernd H. A. Rehm
- Institute of Fundamental Sciences, Massey UniversityPalmerston North, New Zealand
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Chouhan OP, Bandekar D, Hazra M, Baghudana A, Hazra S, Biswas S. Effect of site-directed mutagenesis at the GGEEF domain of the biofilm forming GGEEF protein from Vibrio cholerae. AMB Express 2016; 6:2. [PMID: 26728467 PMCID: PMC4700032 DOI: 10.1186/s13568-015-0168-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2015] [Accepted: 12/11/2015] [Indexed: 01/05/2023] Open
Abstract
Vibrio cholerae, the cause of seven noted pandemics, leads a dual lifecycle—one in the human host in its virulent form, and the other as a sessile, non-virulent bacterium in aquatic bodies in surface biofilms. Surface biofilms have been attributed to be associated with a ubiquitous protein domain present in all branches of bacteria, known as the GGD(/E)EF domain. While the diguanlyate cyclase activities of these proteins are universally established, the role of these proteins as diguanlyate-specific phosphodiesterases in conjunction with a EAL domain has also been reported. The VC0395_0300 protein from V. cholerae which shows biofilm forming abilities also acts as a phosphodiesterase. Interestingly, this GGD(/E)EF protein contains a EAL site in the reverse orientation. We attempted to mutate the GGEEF signature along the sequence by site-directed mutagenesis. The resultant mutants (Sebox5–7) did not show much difference in phosphodiesterase activity in comparison with the wild type protein (Sebox3), indicating the independence of the phosphodiesterase activity of the protein from the GGD(/E)EF domain. However, the ability of the mutants to form surface biofilm was significantly lesser in the case of mutations in the three central positions of the signature domain.
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Control of Biofilms with the Fatty Acid Signaling Molecule cis-2-Decenoic Acid. Pharmaceuticals (Basel) 2015; 8:816-35. [PMID: 26610524 PMCID: PMC4695811 DOI: 10.3390/ph8040816] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Revised: 11/11/2015] [Accepted: 11/18/2015] [Indexed: 12/26/2022] Open
Abstract
Biofilms are complex communities of microorganisms in organized structures attached to surfaces. Importantly, biofilms are a major cause of bacterial infections in humans, and remain one of the most significant challenges to modern medical practice. Unfortunately, conventional therapies have shown to be inadequate in the treatment of most chronic biofilm infections based on the extraordinary innate tolerance of biofilms to antibiotics. Antagonists of quorum sensing signaling molecules have been used as means to control biofilms. QS and other cell-cell communication molecules are able to revert biofilm tolerance, prevent biofilm formation and disrupt fully developed biofilms, albeit with restricted effectiveness. Recently however, it has been demonstrated that Pseudomonas aeruginosa produces a small messenger molecule cis-2-decenoic acid (cis-DA) that shows significant promise as an effective adjunctive to antimicrobial treatment of biofilms. This molecule is responsible for induction of the native biofilm dispersion response in a range of Gram-negative and Gram-positive bacteria and in yeast, and has been shown to reverse persistence, increase microbial metabolic activity and significantly enhance the cidal effects of conventional antimicrobial agents. In this manuscript, the use of cis-2-decenoic acid as a novel agent for biofilm control is discussed. Stimulating the biofilm dispersion response as a novel antimicrobial strategy holds significant promise for enhanced treatment of infections and in the prevention of biofilm formation.
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Aragon IM, Pérez-Mendoza D, Moscoso JA, Faure E, Guery B, Gallegos MT, Filloux A, Ramos C. Diguanylate cyclase DgcP is involved in plant and human Pseudomonas spp. infections. Environ Microbiol 2015; 17:4332-51. [PMID: 25809128 DOI: 10.1111/1462-2920.12856] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 03/06/2015] [Indexed: 12/22/2022]
Abstract
The second messenger cyclic di-GMP (c-di-GMP) controls the transition between different lifestyles in bacterial pathogens. Here, we report the identification of DgcP (diguanylate cyclase conserved in Pseudomonads), whose activity in the olive tree pathogen Pseudomonas savastanoi pv. savastanoi is dependent on the integrity of its GGDEF domain. Furthermore, deletion of the dgcP gene revealed that DgcP negatively regulates motility and positively controls biofilm formation in both the olive tree pathogen P. savastanoi pv. savastanoi and the human opportunistic pathogen Pseudomonas aeruginosa. Overexpression of the dgcP gene in P. aeruginosa PAK led to increased exopolysaccharide production and upregulation of the type VI secretion system; in turn, it repressed the type III secretion system, which is a hallmark of chronic infections and persistence for P. aeruginosa. Deletion of the dgcP gene in P. savastanoi pv. savastanoi NCPPB 3335 and P. aeruginosa PAK reduced their virulence in olive plants and in a mouse acute lung injury model respectively. Our results show that diguanylate cyclase DgcP is a conserved Pseudomonas protein with a role in virulence, and confirm the existence of common c-di-GMP signalling pathways that are capable of regulating plant and human Pseudomonas spp. infections.
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Affiliation(s)
- Isabel M Aragon
- Instituto de Hortofruticultura Subtropical y Mediterránea 'La Mayora', Facultad de Ciencias, Universidad de Málaga-CSIC (IHSM-UMA-CSIC), Área de Genética, Campus de Teatinos, Málaga, E-29010, Spain
- Dpto. Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín, CSIC, Granada, Spain
- Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, South Kensington Campus, Flowers Building, London, SW7 2AZ, UK
| | - Daniel Pérez-Mendoza
- Dpto. Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín, CSIC, Granada, Spain
| | - Joana A Moscoso
- Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, South Kensington Campus, Flowers Building, London, SW7 2AZ, UK
| | - Emmanuel Faure
- Pseudomonas aeruginosa host-pathogen translational research group, Lille School of Medicine, UDSL, Lille North of France University, Lille, France
| | - Benoit Guery
- Pseudomonas aeruginosa host-pathogen translational research group, Lille School of Medicine, UDSL, Lille North of France University, Lille, France
| | - María-Trinidad Gallegos
- Dpto. Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín, CSIC, Granada, Spain
| | - Alain Filloux
- Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, South Kensington Campus, Flowers Building, London, SW7 2AZ, UK
| | - Cayo Ramos
- Instituto de Hortofruticultura Subtropical y Mediterránea 'La Mayora', Facultad de Ciencias, Universidad de Málaga-CSIC (IHSM-UMA-CSIC), Área de Genética, Campus de Teatinos, Málaga, E-29010, Spain
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Genome-Based Comparison of Cyclic Di-GMP Signaling in Pathogenic and Commensal Escherichia coli Strains. J Bacteriol 2015; 198:111-26. [PMID: 26303830 DOI: 10.1128/jb.00520-15] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 08/21/2015] [Indexed: 01/22/2023] Open
Abstract
UNLABELLED The ubiquitous bacterial second messenger cyclic di-GMP (c-di-GMP) has recently become prominent as a trigger for biofilm formation in many bacteria. It is generated by diguanylate cyclases (DGCs; with GGDEF domains) and degraded by specific phosphodiesterases (PDEs; containing either EAL or HD-GYP domains). Most bacterial species contain multiples of these proteins with some having specific functions that are based on direct molecular interactions in addition to their enzymatic activities. Escherichia coli K-12 laboratory strains feature 29 genes encoding GGDEF and/or EAL domains, resulting in a set of 12 DGCs, 13 PDEs, and four enzymatically inactive "degenerate" proteins that act by direct macromolecular interactions. We present here a comparative analysis of GGDEF/EAL domain-encoding genes in 61 genomes of pathogenic, commensal, and probiotic E. coli strains (including enteric pathogens such as enteroaggregative, enterohemorrhagic, enteropathogenic, enterotoxigenic, and adherent and invasive Escherichia coli and the 2011 German outbreak O104:H4 strain, as well as extraintestinal pathogenic E. coli, such as uropathogenic and meningitis-associated E. coli). We describe additional genes for two membrane-associated DGCs (DgcX and DgcY) and four PDEs (the membrane-associated PdeT, as well as the EAL domain-only proteins PdeW, PdeX, and PdeY), thus showing the pangenome of E. coli to contain at least 35 GGDEF/EAL domain proteins. A core set of only eight proteins is absolutely conserved in all 61 strains: DgcC (YaiC), DgcI (YliF), PdeB (YlaB), PdeH (YhjH), PdeK (YhjK), PdeN (Rtn), and the degenerate proteins CsrD and CdgI (YeaI). In all other GGDEF/EAL domain genes, diverse point and frameshift mutations, as well as small or large deletions, were discovered in various strains. IMPORTANCE Our analysis reveals interesting trends in pathogenic Escherichia coli that could reflect different host cell adherence mechanisms. These may either benefit from or be counteracted by the c-di-GMP-stimulated production of amyloid curli fibers and cellulose. Thus, EAEC, which adhere in a "stacked brick" biofilm mode, have a potential for high c-di-GMP accumulation due to DgcX, a strongly expressed additional DGC. In contrast, EHEC and UPEC, which use alternative adherence mechanisms, tend to have extra PDEs, suggesting that low cellular c-di-GMP levels are crucial for these strains under specific conditions. Overall, our study also indicates that GGDEF/EAL domain proteins evolve rapidly and thereby contribute to adaptation to host-specific and environmental niches of various types of E. coli.
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40
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Leighton TL, Buensuceso RNC, Howell PL, Burrows LL. Biogenesis of Pseudomonas aeruginosa type IV pili and regulation of their function. Environ Microbiol 2015; 17:4148-63. [PMID: 25808785 DOI: 10.1111/1462-2920.12849] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Revised: 03/13/2015] [Accepted: 03/14/2015] [Indexed: 12/27/2022]
Abstract
Type IV pili (T4P) are bacterial virulence factors involved in a wide variety of functions including deoxyribonucleic acid uptake, surface attachment, biofilm formation and twitching motility. While T4P are common surface appendages, the systems that assemble them and the regulation of their function differ between species. Pseudomonas aeruginosa, Neisseria spp. and Myxococcus xanthus are common model systems used to study T4P biology. This review focuses on recent advances in P. aeruginosa T4P structural biology, and the regulatory pathways controlling T4P biogenesis and function.
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Affiliation(s)
- Tiffany L Leighton
- Department of Biochemistry and Biomedical Sciences, Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON, Canada
| | - Ryan N C Buensuceso
- Department of Biochemistry and Biomedical Sciences, Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON, Canada
| | - P Lynne Howell
- Program in Molecular Structure & Function, The Hospital for Sick Children, Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Lori L Burrows
- Department of Biochemistry and Biomedical Sciences, Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON, Canada
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Sheibani-Tezerji R, Naveed M, Jehl MA, Sessitsch A, Rattei T, Mitter B. The genomes of closely related Pantoea ananatis maize seed endophytes having different effects on the host plant differ in secretion system genes and mobile genetic elements. Front Microbiol 2015; 6:440. [PMID: 26029184 PMCID: PMC4428218 DOI: 10.3389/fmicb.2015.00440] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 04/23/2015] [Indexed: 11/13/2022] Open
Abstract
The seed as a habitat for microorganisms is as yet under-explored and has quite distinct characteristics as compared to other vegetative plant tissues. In this study, we investigated three closely related P. ananatis strains (named S6, S7, and S8), which were isolated from maize seeds of healthy plants. Plant inoculation experiments revealed that each of these strains exhibited a different phenotype ranging from weak pathogenic (S7), commensal (S8), to a beneficial, growth-promoting effect (S6) in maize. We performed a comparative genomics analysis in order to find genetic determinants responsible for the differences observed. Recent studies provided exciting insight into the genetic drivers of niche adaption and functional diversification of the genus Pantoea. However, we report here for the first time on the analysis of P. ananatis strains colonizing the same ecological niche but showing distinct interaction strategies with the host plant. Our comparative analysis revealed that genomes of these three strains are highly similar. However, genomic differences in genes encoding protein secretion systems and putative effectors, and transposase/integrases/phage related genes could be observed.
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Affiliation(s)
- Raheleh Sheibani-Tezerji
- Bioresources Unit, Health and Environment Department, AIT Austrian Institute of Technology GmbHTulln, Austria
- Division of Computational System Biology, Department of Microbiology and Ecosystem Science, University of ViennaVienna, Austria
| | - Muhammad Naveed
- Bioresources Unit, Health and Environment Department, AIT Austrian Institute of Technology GmbHTulln, Austria
| | - Marc-André Jehl
- Division of Computational System Biology, Department of Microbiology and Ecosystem Science, University of ViennaVienna, Austria
| | - Angela Sessitsch
- Bioresources Unit, Health and Environment Department, AIT Austrian Institute of Technology GmbHTulln, Austria
| | - Thomas Rattei
- Division of Computational System Biology, Department of Microbiology and Ecosystem Science, University of ViennaVienna, Austria
| | - Birgit Mitter
- Bioresources Unit, Health and Environment Department, AIT Austrian Institute of Technology GmbHTulln, Austria
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Laventie BJ, Nesper J, Ahrné E, Glatter T, Schmidt A, Jenal U. Capture compound mass spectrometry--a powerful tool to identify novel c-di-GMP effector proteins. J Vis Exp 2015. [PMID: 25867682 DOI: 10.3791/51404] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Considerable progress has been made during the last decade towards the identification and characterization of enzymes involved in the synthesis (diguanylate cyclases) and degradation (phosphodiesterases) of the second messenger c-di-GMP. In contrast, little information is available regarding the molecular mechanisms and cellular components through which this signaling molecule regulates a diverse range of cellular processes. Most of the known effector proteins belong to the PilZ family or are degenerated diguanylate cyclases or phosphodiesterases that have given up on catalysis and have adopted effector function. Thus, to better define the cellular c-di-GMP network in a wide range of bacteria experimental methods are required to identify and validate novel effectors for which reliable in silico predictions fail. We have recently developed a novel Capture Compound Mass Spectrometry (CCMS) based technology as a powerful tool to biochemically identify and characterize c-di-GMP binding proteins. This technique has previously been reported to be applicable to a wide range of organisms(1). Here we give a detailed description of the protocol that we utilize to probe such signaling components. As an example, we use Pseudomonas aeruginosa, an opportunistic pathogen in which c-di-GMP plays a critical role in virulence and biofilm control. CCMS identified 74% (38/51) of the known or predicted components of the c-di-GMP network. This study explains the CCMS procedure in detail, and establishes it as a powerful and versatile tool to identify novel components involved in small molecule signaling.
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Affiliation(s)
| | - Jutta Nesper
- Focal Area Infection Biology, Biozentrum of the University of Basel
| | - Erik Ahrné
- Proteomics Core Facility, Biozentrum of the University of Basel
| | - Timo Glatter
- Proteomics Core Facility, Biozentrum of the University of Basel
| | | | - Urs Jenal
- Focal Area Infection Biology, Biozentrum of the University of Basel;
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Cursino L, Athinuwat D, Patel KR, Galvani CD, Zaini PA, Li Y, De La Fuente L, Hoch HC, Burr TJ, Mowery P. Characterization of the Xylella fastidiosa PD1671 gene encoding degenerate c-di-GMP GGDEF/EAL domains, and its role in the development of Pierce's disease. PLoS One 2015; 10:e0121851. [PMID: 25811864 PMCID: PMC4374697 DOI: 10.1371/journal.pone.0121851] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 02/16/2015] [Indexed: 01/09/2023] Open
Abstract
Xylella fastidiosa is an important phytopathogenic bacterium that causes many serious plant diseases including Pierce's disease of grapevines. X. fastidiosa is thought to induce disease by colonizing and clogging xylem vessels through the formation of cell aggregates and bacterial biofilms. Here we examine the role in X. fastidiosa virulence of an uncharacterized gene, PD1671, annotated as a two-component response regulator with potential GGDEF and EAL domains. GGDEF domains are found in c-di-GMP diguanylate cyclases while EAL domains are found in phosphodiesterases, and these domains are for c-di-GMP production and turnover, respectively. Functional analysis of the PD1671 gene revealed that it affected multiple X. fastidiosa virulence-related phenotypes. A Tn5 PD1671 mutant had a hypervirulent phenotype in grapevines presumably due to enhanced expression of gum genes leading to increased exopolysaccharide levels that resulted in elevated biofilm formation. Interestingly, the PD1671 mutant also had decreased motility in vitro but did not show a reduced distribution in grapevines following inoculation. Given these responses, the putative PD1671 protein may be a negative regulator of X. fastidiosa virulence.
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Affiliation(s)
- Luciana Cursino
- Department of Plant Pathology and Plant Microbe Biology, Cornell University, New York State Agricultural Experiment Station, Geneva, New York, United States of America
- Department of Biology, Hobart and William Smith Colleges Geneva, New York, United States of America
| | - Dusit Athinuwat
- Department of Plant Pathology and Plant Microbe Biology, Cornell University, New York State Agricultural Experiment Station, Geneva, New York, United States of America
| | - Kelly R. Patel
- Department of Biology, Hobart and William Smith Colleges Geneva, New York, United States of America
| | - Cheryl D. Galvani
- Department of Plant Pathology and Plant Microbe Biology, Cornell University, New York State Agricultural Experiment Station, Geneva, New York, United States of America
- Department of Biology, Hobart and William Smith Colleges Geneva, New York, United States of America
| | - Paulo A. Zaini
- Department of Plant Pathology and Plant Microbe Biology, Cornell University, New York State Agricultural Experiment Station, Geneva, New York, United States of America
| | - Yaxin Li
- Department of Plant Pathology and Plant Microbe Biology, Cornell University, New York State Agricultural Experiment Station, Geneva, New York, United States of America
| | - Leonardo De La Fuente
- Department of Plant Pathology and Plant Microbe Biology, Cornell University, New York State Agricultural Experiment Station, Geneva, New York, United States of America
| | - Harvey C. Hoch
- Department of Plant Pathology and Plant Microbe Biology, Cornell University, New York State Agricultural Experiment Station, Geneva, New York, United States of America
| | - Thomas J. Burr
- Department of Plant Pathology and Plant Microbe Biology, Cornell University, New York State Agricultural Experiment Station, Geneva, New York, United States of America
| | - Patricia Mowery
- Department of Biology, Hobart and William Smith Colleges Geneva, New York, United States of America
- * E-mail:
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Wesseling W. Beneficial biofilms in marine aquaculture? Linking points of biofilm formation mechanisms in <em>Pseudomonas aeruginosa</em> and <em>Pseudoalteromonas</em> species. AIMS BIOENGINEERING 2015. [DOI: 10.3934/bioeng.2015.3.104] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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45
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Chekabab SM, Harel J, Dozois CM. Interplay between genetic regulation of phosphate homeostasis and bacterial virulence. Virulence 2014; 5:786-93. [PMID: 25483775 DOI: 10.4161/viru.29307] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Bacterial pathogens, including those of humans, animals, and plants, encounter phosphate (Pi)-limiting or Pi-rich environments in the host, depending on the site of infection. The environmental Pi-concentration results in modulation of expression of the Pho regulon that allows bacteria to regulate phosphate assimilation pathways accordingly. In many cases, modulation of Pho regulon expression also results in concomitant changes in virulence phenotypes. Under Pi-limiting conditions, bacteria use the transcriptional-response regulator PhoB to translate the Pi starvation signal sensed by the bacterium into gene activation or repression. This regulator is employed not only for the maintenance of bacterial Pi homeostasis but also to differentially regulate virulence. The Pho regulon is therefore not only a regulatory circuit of phosphate homeostasis but also plays an important adaptive role in stress response and bacterial virulence. Here we focus on recent findings regarding the mechanisms of gene regulation that underlie the virulence responses to Pi stress in Vibrio cholerae, Pseudomonas spp., and pathogenic E. coli.
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Affiliation(s)
- Samuel Mohammed Chekabab
- a Centre de Recherche en Infectiologie Porcine et Avicole (CRIPA); Université de Montréal; Faculté de Médecine Vétérinaire ; Saint-Hyacinthe , QC Canada
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[Networks involving quorum sensing, cyclic-di-GMP and nitric oxide on biofilm production in bacteria]. Rev Argent Microbiol 2014; 46:242-55. [PMID: 25444134 DOI: 10.1016/s0325-7541(14)70079-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Accepted: 06/03/2014] [Indexed: 01/06/2023] Open
Abstract
Bacterial biofilms are ubiquitous in nature, and their flexibility is derived in part from a complex extracellular matrix that can be made-to-order to cope with environmental demand. Although common developmental stages leading to biofilm formation have been described, an in-depth knowledge of genetic and signaling is required to understand biofilm formation. Bacteria detect changes in population density by quorum sensing and particular environmental conditions, using signals such as cyclic di-GMP or nitric oxide. The significance of understanding these signaling pathways lies in that they control a broad variety of functions such as biofilm formation, and motility, providing benefits to bacteria as regards host colonization, defense against competitors, and adaptation to changing environments. Due to the importance of these features, we here review the signaling network and regulatory connections among quorum sensing, c-di-GMP and nitric oxide involving biofilm formation.
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47
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Bile acids and bicarbonate inversely regulate intracellular cyclic di-GMP in Vibrio cholerae. Infect Immun 2014; 82:3002-14. [PMID: 24799624 DOI: 10.1128/iai.01664-14] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Vibrio cholerae is a Gram-negative bacterium that persists in aquatic reservoirs and causes the diarrheal disease cholera upon entry into a human host. V. cholerae employs the second messenger molecule 3',5'-cyclic diguanylic acid (c-di-GMP) to transition between these two distinct lifestyles. c-di-GMP is synthesized by diguanylate cyclase (DGC) enzymes and hydrolyzed by phosphodiesterase (PDE) enzymes. Bacteria typically encode many different DGCs and PDEs within their genomes. Presumably, each enzyme senses and responds to cognate environmental cues by alteration of enzymatic activity. c-di-GMP represses the expression of virulence factors in V. cholerae, and it is predicted that the intracellular concentration of c-di-GMP is low during infection. Contrary to this model, we found that bile acids, a prevalent constituent of the human proximal small intestine, increase intracellular c-di-GMP in V. cholerae. We identified four c-di-GMP turnover enzymes that contribute to increased intracellular c-di-GMP in the presence of bile acids, and deletion of these enzymes eliminates the bile induction of c-di-GMP and biofilm formation. Furthermore, this bile-mediated increase in c-di-GMP is quenched by bicarbonate, the intestinal pH buffer secreted by intestinal epithelial cells. Our results lead us to propose that V. cholerae senses distinct microenvironments within the small intestine using bile and bicarbonate as chemical cues and responds by modulating the intracellular concentration of c-di-GMP.
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Fischer A, Kambara K, Meyer H, Stenz L, Bonetti EJ, Girard M, Lalk M, Francois P, Schrenzel J. GdpS contributes to Staphylococcus aureus biofilm formation by regulation of eDNA release. Int J Med Microbiol 2014; 304:284-99. [DOI: 10.1016/j.ijmm.2013.10.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Revised: 10/25/2013] [Accepted: 10/27/2013] [Indexed: 11/30/2022] Open
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49
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Novak EA, Sultan SZ, Motaleb MA. The cyclic-di-GMP signaling pathway in the Lyme disease spirochete, Borrelia burgdorferi. Front Cell Infect Microbiol 2014; 4:56. [PMID: 24822172 PMCID: PMC4013479 DOI: 10.3389/fcimb.2014.00056] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Accepted: 04/13/2014] [Indexed: 11/13/2022] Open
Abstract
In nature, the Lyme disease spirochete Borrelia burgdorferi cycles between the unrelated environments of the Ixodes tick vector and mammalian host. In order to survive transmission between hosts, B. burgdorferi must be able to not only detect changes in its environment, but also rapidly and appropriately respond to these changes. One manner in which this obligate parasite regulates and adapts to its changing environment is through cyclic-di-GMP (c-di-GMP) signaling. c-di-GMP has been shown to be instrumental in orchestrating the adaptation of B. burgdorferi to the tick environment. B. burgdorferi possesses only one set of c-di-GMP-metabolizing genes (one diguanylate cyclase and two distinct phosphodiesterases) and one c-di-GMP-binding PilZ-domain protein designated as PlzA. While studies in the realm of c-di-GMP signaling in B. burgdorferi have exploded in the last few years, there are still many more questions than answers. Elucidation of the importance of c-di-GMP signaling to B. burgdorferi may lead to the identification of mechanisms that are critical for the survival of B. burgdorferi in the tick phase of the enzootic cycle as well as potentially delineate a role (if any) c-di-GMP may play in the transmission and virulence of B. burgdorferi during the enzootic cycle, thereby enabling the development of effective drugs for the prevention and/or treatment of Lyme disease.
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Affiliation(s)
| | | | - Md. A. Motaleb
- Department of Microbiology and Immunology, East Carolina University Brody School of MedicineGreenville, NC, USA
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50
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Pérez-Mendoza D, Aragón IM, Prada-Ramírez HA, Romero-Jiménez L, Ramos C, Gallegos MT, Sanjuán J. Responses to elevated c-di-GMP levels in mutualistic and pathogenic plant-interacting bacteria. PLoS One 2014; 9:e91645. [PMID: 24626229 PMCID: PMC3953490 DOI: 10.1371/journal.pone.0091645] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Accepted: 02/13/2014] [Indexed: 11/18/2022] Open
Abstract
Despite a recent burst of research, knowledge on c-di-GMP signaling pathways remains largely fragmentary and molecular mechanisms of regulation and even c-di-GMP targets are yet unknown for most bacteria. Besides genomics or bioinformatics, accompanying alternative approaches are necessary to reveal c-di-GMP regulation in bacteria with complex lifestyles. We have approached this study by artificially altering the c-di-GMP economy of diverse pathogenic and mutualistic plant-interacting bacteria and examining the effects on the interaction with their respective host plants. Phytopathogenic Pseudomonas and symbiotic Rhizobium strains with enhanced levels of intracellular c-di-GMP displayed common free-living responses: reduction of motility, increased production of extracellular polysaccharides and enhanced biofilm formation. Regarding the interaction with the host plants, P. savastanoi pv. savastanoi cells containing high c-di-GMP levels formed larger knots on olive plants which, however, displayed reduced necrosis. In contrast, development of disease symptoms in P. syringae-tomato or P. syringae-bean interactions did not seem significantly affected by high c-di-GMP. On the other hand, increasing c-di-GMP levels in symbiotic R. etli and R. leguminosarum strains favoured the early stages of the interaction since enhanced adhesion to plant roots, but decreased symbiotic efficiency as plant growth and nitrogen contents were reduced. Our results remark the importance of c-di-GMP economy for plant-interacting bacteria and show the usefulness of our approach to reveal particular stages during plant-bacteria associations which are sensitive to changes in c-di-GMP levels.
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Affiliation(s)
- Daniel Pérez-Mendoza
- Dpto. Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín, CSIC, Granada, Spain
| | - Isabel M. Aragón
- Área de Genética, Universidad de Málaga, Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora”, Universidad de Málaga-CSIC (IHSM-UMA-CSIC), Málaga, Spain
| | - Harold A. Prada-Ramírez
- Dpto. Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín, CSIC, Granada, Spain
| | - Lorena Romero-Jiménez
- Dpto. Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín, CSIC, Granada, Spain
| | - Cayo Ramos
- Área de Genética, Universidad de Málaga, Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora”, Universidad de Málaga-CSIC (IHSM-UMA-CSIC), Málaga, Spain
| | - María-Trinidad Gallegos
- Dpto. Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín, CSIC, Granada, Spain
| | - Juan Sanjuán
- Dpto. Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín, CSIC, Granada, Spain
- * E-mail:
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