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Cancino-Diaz ME, Guerrero-Barajas C, Betanzos-Cabrera G, Cancino-Diaz JC. Nucleotides as Bacterial Second Messengers. Molecules 2023; 28:7996. [PMID: 38138485 PMCID: PMC10745434 DOI: 10.3390/molecules28247996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 11/21/2023] [Accepted: 11/23/2023] [Indexed: 12/24/2023] Open
Abstract
In addition to comprising monomers of nucleic acids, nucleotides have signaling functions and act as second messengers in both prokaryotic and eukaryotic cells. The most common example is cyclic AMP (cAMP). Nucleotide signaling is a focus of great interest in bacteria. Cyclic di-AMP (c-di-AMP), cAMP, and cyclic di-GMP (c-di-GMP) participate in biological events such as bacterial growth, biofilm formation, sporulation, cell differentiation, motility, and virulence. Moreover, the cyclic-di-nucleotides (c-di-nucleotides) produced in pathogenic intracellular bacteria can affect eukaryotic host cells to allow for infection. On the other hand, non-cyclic nucleotide molecules pppGpp and ppGpp are alarmones involved in regulating the bacterial response to nutritional stress; they are also considered second messengers. These second messengers can potentially be used as therapeutic agents because of their immunological functions on eukaryotic cells. In this review, the role of c-di-nucleotides and cAMP as second messengers in different bacterial processes is addressed.
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Affiliation(s)
- Mario E. Cancino-Diaz
- Departamentos Microbiología and Inmunología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Manuel Carpio, Plutarco Elías Calles, Miguel Hidalgo, Ciudad de México 11350, Mexico
| | - Claudia Guerrero-Barajas
- Departamento de Bioprocesos, Unidad Profesional Interdisciplinaria de Biotecnología, Instituto Politécnico Nacional, Av. Acueducto, La Laguna Ticoman, Gustavo A. Madero, Ciudad de México 07340, Mexico;
| | - Gabriel Betanzos-Cabrera
- Área Académica de Nutrición y Medicina, Instituto de Ciencias de la Salud, Universidad Autónoma del Estado de Hidalgo, Carretera Pachuca-Actopan Camino a Tilcuautla s/n, Pueblo San Juan Tilcuautla, Pachuca Hidalgo 42160, Mexico;
| | - Juan C. Cancino-Diaz
- Departamentos Microbiología and Inmunología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Manuel Carpio, Plutarco Elías Calles, Miguel Hidalgo, Ciudad de México 11350, Mexico
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2
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Römling U, Cao LY, Bai FW. Evolution of cyclic di-GMP signalling on a short and long term time scale. MICROBIOLOGY (READING, ENGLAND) 2023; 169:001354. [PMID: 37384391 PMCID: PMC10333796 DOI: 10.1099/mic.0.001354] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 06/13/2023] [Indexed: 07/01/2023]
Abstract
Diversifying radiation of domain families within specific lineages of life indicates the importance of their functionality for the organisms. The foundation for the diversifying radiation of the cyclic di-GMP signalling network that occurred within the bacterial kingdom is most likely based in the outmost adaptability, flexibility and plasticity of the system. Integrative sensing of multiple diverse extra- and intracellular signals is made possible by the N-terminal sensory domains of the modular cyclic di-GMP turnover proteins, mutations in the protein scaffolds and subsequent signal reception by diverse receptors, which eventually rewires opposite host-associated as well as environmental life styles including parallel regulated target outputs. Natural, laboratory and microcosm derived microbial variants often with an altered multicellular biofilm behaviour as reading output demonstrated single amino acid substitutions to substantially alter catalytic activity including substrate specificity. Truncations and domain swapping of cyclic di-GMP signalling genes and horizontal gene transfer suggest rewiring of the network. Presence of cyclic di-GMP signalling genes on horizontally transferable elements in particular observed in extreme acidophilic bacteria indicates that cyclic di-GMP signalling and biofilm components are under selective pressure in these types of environments. On a short and long term evolutionary scale, within a species and in families within bacterial orders, respectively, the cyclic di-GMP signalling network can also rapidly disappear. To investigate variability of the cyclic di-GMP signalling system on various levels will give clues about evolutionary forces and discover novel physiological and metabolic pathways affected by this intriguing second messenger signalling system.
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Affiliation(s)
- Ute Römling
- Department of Microbiology, Tumor and Cell Biology, Biomedicum, Karolinska Institutet, Stockholm, Sweden
| | - Lian-Ying Cao
- Department of Microbiology, Tumor and Cell Biology, Biomedicum, Karolinska Institutet, Stockholm, Sweden
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, PR China
| | - Feng-Wu Bai
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, PR China
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3
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Baek J, Yoon H. Cyclic di-GMP Modulates a Metabolic Flux for Carbon Utilization in Salmonella enterica Serovar Typhimurium. Microbiol Spectr 2023; 11:e0368522. [PMID: 36744926 PMCID: PMC10100716 DOI: 10.1128/spectrum.03685-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 01/16/2023] [Indexed: 02/07/2023] Open
Abstract
Salmonella enterica serovar Typhimurium is an enteric pathogen spreading via the fecal-oral route. Transmission across humans, animals, and environmental reservoirs has forced this pathogen to rapidly respond to changing environments and adapt to new environmental conditions. Cyclic di-GMP (c-di-GMP) is a second messenger that controls the transition between planktonic and sessile lifestyles, in response to environmental cues. Our study reveals the potential of c-di-GMP to alter the carbon metabolic pathways in S. Typhimurium. Cyclic di-GMP overproduction decreased the transcription of genes that encode components of three phosphoenolpyruvate (PEP):carbohydrate phosphotransferase systems (PTSs) allocated for the uptake of glucose (PTSGlc), mannose (PTSMan), and fructose (PTSFru). PTS gene downregulation by c-di-GMP was alleviated in the absence of the three regulators, SgrS, Mlc, and Cra, suggesting their intermediary roles between c-di-GMP and PTS regulation. Moreover, Cra was found to bind to the promoters of ptsG, manX, and fruB. In contrast, c-di-GMP increased the transcription of genes important for gluconeogenesis. However, this effect of c-di-GMP in gluconeogenesis disappeared in the absence of Cra, indicating that Cra is a pivotal regulator that coordinates the carbon flux between PTS-mediated sugar uptake and gluconeogenesis, in response to cellular c-di-GMP concentrations. Since gluconeogenesis supplies precursor sugars required for extracellular polysaccharide production, Salmonella may exploit c-di-GMP as a dual-purpose signal that rewires carbon flux from glycolysis to gluconeogenesis and promotes biofilm formation using the end products of gluconeogenesis. This study sheds light on a new role for c-di-GMP in modulating carbon flux, to coordinate bacterial behavior in response to hostile environments. IMPORTANCE Cyclic di-GMP is a central signaling molecule that determines the transition between motile and nonmotile lifestyles in many bacteria. It stimulates biofilm formation at high concentrations but leads to biofilm dispersal and planktonic status at low concentrations. This study provides new insights into the role of c-di-GMP in programming carbon metabolic pathways. An increase in c-di-GMP downregulated the expression of PTS genes important for sugar uptake, while simultaneously upregulating the transcription of genes important for bacterial gluconeogenesis. The directly opposing effects of c-di-GMP on sugar metabolism were mediated by Cra (catabolite repressor/activator), a dual transcriptional regulator that modulates the direction of carbon flow. Salmonella may potentially harness c-di-GMP to promote its survival and fitness in hostile environments via the coordination of carbon metabolic pathways and the induction of biofilm formation.
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Affiliation(s)
- Jiwon Baek
- Department of Molecular Science and Technology, Ajou University, Suwon, Republic of Korea
| | - Hyunjin Yoon
- Department of Molecular Science and Technology, Ajou University, Suwon, Republic of Korea
- Department of Applied Chemistry and Biological Engineering, Ajou University, Suwon, Republic of Korea
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4
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Escobar MR, Lepek VC, Basile LA. Influence of cyclic di-GMP metabolism to T3SS expression, biofilm formation and symbiosis efficiency in Mesorhizobium japonicum MAFF303099. FEMS Microbiol Lett 2023; 370:fnad087. [PMID: 37632199 DOI: 10.1093/femsle/fnad087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 07/26/2023] [Accepted: 08/22/2023] [Indexed: 08/27/2023] Open
Abstract
A link between the T3SS and inhibition of swimming motility by the transcriptional regulator TtsI in Mesorhizobium japonicum MAFF303099 has been previously reported. Here, we show that mutants in T3SS components display impaired biofilm formation capacity, indicating that a functional T3SS, or at least pili formation, is required for this process. As a first approach to the cdiG regulation network in this bacterium, we started a study of the second messenger cdiG by overexpressing or by deleting some genes encoding cdiG metabolizing enzymes. Overexpression of two putative PDEs as well as deletion of various DGCs led to reduced biofilm formation on glass tubes. Mutation of dgc9509 also affected negatively the nodulation and symbiosis efficiency on Lotus plants, which can be related to the observed reduction in adhesion to plant roots. Results from transcriptional nopX- and ttsI-promoter-lacZ fusions suggested that cdiG negatively regulates T3SS expression in M. japonicum MAFF303099.
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Affiliation(s)
- Mariel R Escobar
- Instituto de Investigaciones Biotecnológicas "Dr. Rodolfo Ugalde", Escuela de Bio y Nanotecnologías, Universidad Nacional de San Martín (IIBio-EByN-UNSAM), CONICET. Av. 25 de Mayo y Francia, San Martín, Buenos Aires, Argentina
| | - Viviana C Lepek
- Instituto de Investigaciones Biotecnológicas "Dr. Rodolfo Ugalde", Escuela de Bio y Nanotecnologías, Universidad Nacional de San Martín (IIBio-EByN-UNSAM), CONICET. Av. 25 de Mayo y Francia, San Martín, Buenos Aires, Argentina
| | - Laura A Basile
- Instituto de Investigaciones Biotecnológicas "Dr. Rodolfo Ugalde", Escuela de Bio y Nanotecnologías, Universidad Nacional de San Martín (IIBio-EByN-UNSAM), CONICET. Av. 25 de Mayo y Francia, San Martín, Buenos Aires, Argentina
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5
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Römling U. Is biofilm formation intrinsic to the origin of life? Environ Microbiol 2023; 25:26-39. [PMID: 36655713 PMCID: PMC10086821 DOI: 10.1111/1462-2920.16179] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 08/19/2022] [Indexed: 01/21/2023]
Abstract
Biofilms are multicellular, often surface-associated, communities of autonomous cells. Their formation is the natural mode of growth of up to 80% of microorganisms living on this planet. Biofilms refractory towards antimicrobial agents and the actions of the immune system due to their tolerance against multiple environmental stresses. But how did biofilm formation arise? Here, I argue that the biofilm lifestyle has its foundation already in the fundamental, surface-triggered chemical reactions and energy preserving mechanisms that enabled the development of life on earth. Subsequently, prototypical biofilm formation has evolved and diversified concomitantly in composition, cell morphology and regulation with the expansion of prokaryotic organisms and their radiation by occupation of diverse ecological niches. This ancient origin of biofilm formation thus mirrors the harnessing environmental conditions that have been the rule rather than the exception in microbial life. The subsequent emergence of the association of microbes, including recent human pathogens, with higher organisms can be considered as the entry into a nutritional and largely stress-protecting heaven. Nevertheless, basic mechanisms of biofilm formation have surprisingly been conserved and refunctionalized to promote sustained survival in new environments.
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Affiliation(s)
- Ute Römling
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
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6
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Gu Y, Lu H, Shao Y, Fu D, Wu J, Hu J, Tu J, Song X, Qi K. Acetoacetyl-CoA transferase ydiF regulates the biofilm formation of avian pathogenic Escherichia coli. Res Vet Sci 2022; 153:144-152. [PMID: 36375381 DOI: 10.1016/j.rvsc.2022.10.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 09/12/2022] [Accepted: 10/23/2022] [Indexed: 11/06/2022]
Abstract
Avian pathogenic Escherichia coli (APEC) causes persistent infection of poultry and multi-system diseases, which seriously endanger the development of the poultry industry. Biofilm allows bacteria to adapt to the natural environment and plays an important role in resistance to the external environment and the pathogenicity of APEC, but the mechanism of its formation and regulatory network have not been clarified. In this study, we used a Tn5 transposon random mutation library constructed with APEC and identified ydiF, a gene that has not previously been recognized in E. coli biofilm formation. To confirm that the ydiF gene really can regulate the formation of APEC biofilm, the ydiF gene deletion strain was constructed using APEC81. Protein association networks prediction results show that ydiF is mainly associated with genes related to the metabolism of sugars and fatty acids. Deletion of the ydiF gene significantly reduces the formation of APEC biofilm and scanning electron microscopy indicated that the degree of adhesion between the bacteria was also reduced. The deletion of the ydiF gene also significantly reduced the motility of APEC81 and through transmission electron microscopy APEC81 was observed to have significantly fewer flagella. However, the colony morphology of APEC81 on Congo red and Coomassie brilliant blue media was unaffected. The results of fluorescence quantification showed that the deletion of the ydiF gene caused a down-regulation in the transcription of genes related to the second messenger, sugar metabolism, and quorum sensing. These results indicate that ydiF plays an important role in biofilm formation and the movement of APEC. In addition, it may be possible to regulate the formation of APEC biofilms by different methods such as by regulating the second messenger and metabolic system.
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Affiliation(s)
- Yi Gu
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, Anhui Agricultural University, Hefei 230036, Anhui, China
| | - Huiqi Lu
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, Anhui Agricultural University, Hefei 230036, Anhui, China
| | - Ying Shao
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, Anhui Agricultural University, Hefei 230036, Anhui, China
| | - Dandan Fu
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, Anhui Agricultural University, Hefei 230036, Anhui, China
| | - Jianmei Wu
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, Anhui Agricultural University, Hefei 230036, Anhui, China
| | - Jiangang Hu
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, Anhui Agricultural University, Hefei 230036, Anhui, China
| | - Jian Tu
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, Anhui Agricultural University, Hefei 230036, Anhui, China
| | - Xiangjun Song
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, Anhui Agricultural University, Hefei 230036, Anhui, China
| | - Kezong Qi
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, Anhui Agricultural University, Hefei 230036, Anhui, China.
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7
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Li F, Cao L, Bähre H, Kim SK, Schroeder K, Jonas K, Koonce K, Mekonnen SA, Mohanty S, Bai F, Brauner A, Lee VT, Rohde M, Römling U. Patatin-like phospholipase CapV in Escherichia coli - morphological and physiological effects of one amino acid substitution. NPJ Biofilms Microbiomes 2022; 8:39. [PMID: 35546554 PMCID: PMC9095652 DOI: 10.1038/s41522-022-00294-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 03/22/2022] [Indexed: 11/09/2022] Open
Abstract
In rod-shaped bacteria, morphological plasticity occurs in response to stress, which blocks cell division to promote filamentation. We demonstrate here that overexpression of the patatin-like phospholipase variant CapVQ329R, but not CapV, causes pronounced sulA-independent pyridoxine-inhibited cell filamentation in the Escherichia coli K-12-derivative MG1655 associated with restriction of flagella production and swimming motility. Conserved amino acids in canonical patatin-like phospholipase A motifs, but not the nucleophilic serine, are required to mediate CapVQ329R phenotypes. Furthermore, CapVQ329R production substantially alters the lipidome and colony morphotype including rdar biofilm formation with modulation of the production of the biofilm activator CsgD, and affects additional bacterial traits such as the efficiency of phage infection and antimicrobial susceptibility. Moreover, genetically diverse commensal and pathogenic E. coli strains and Salmonella typhimurium responded with cell filamentation and modulation in colony morphotype formation to CapVQ329R expression. In conclusion, this work identifies the CapV variant CapVQ329R as a pleiotropic regulator, emphasizes a scaffold function for patatin-like phospholipases, and highlights the impact of the substitution of a single conserved amino acid for protein functionality and alteration of host physiology.
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Affiliation(s)
- Fengyang Li
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, 17177, Stockholm, Sweden.
- College of Veterinary Medicine, Jilin University, Changchun, China.
| | - Lianying Cao
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, 17177, Stockholm, Sweden
| | - Heike Bähre
- Research Core Unit Metabolomics, Hannover Medical School, Hannover, Germany
| | - Soo-Kyoung Kim
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, 20742, USA
| | - Kristen Schroeder
- Science for Life Laboratory, Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Kristina Jonas
- Science for Life Laboratory, Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Kira Koonce
- Science for Life Laboratory, Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Solomon A Mekonnen
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, 20742, USA
| | - Soumitra Mohanty
- Department of Microbiology, Tumor and Cell Biology, Division of Clinical Microbiology, Karolinska Institutet and Karolinska University Hospital, 17176, Stockholm, Sweden
| | - Fengwu Bai
- School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 200240, Shanghai, China
| | - Annelie Brauner
- Department of Microbiology, Tumor and Cell Biology, Division of Clinical Microbiology, Karolinska Institutet and Karolinska University Hospital, 17176, Stockholm, Sweden
| | - Vincent T Lee
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, 20742, USA
| | - Manfred Rohde
- Central Facility for Microscopy, Helmholtz Center for Infection Research, Braunschweig, Germany
| | - Ute Römling
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, 17177, Stockholm, Sweden.
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Characterization of a Novel Regulator of Biofilm Formation in the Pathogen Legionella pneumophila. Biomolecules 2022; 12:biom12020225. [PMID: 35204726 PMCID: PMC8961574 DOI: 10.3390/biom12020225] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 01/23/2022] [Accepted: 01/24/2022] [Indexed: 12/22/2022] Open
Abstract
Legionella pneumophila is a Gram-negative, facultative intracellular pathogen that causes severe pneumonia known as Legionnaires’ disease. The bacterium causes disease when contaminated water is aerosolized and subsequently inhaled by individuals, which allows the bacteria to gain access to the lungs, where they infect alveolar macrophages. L. pneumophila is ubiquitous in the environment, where it survives by growing in biofilms, intracellularly within protozoa, and planktonically. Biofilms are a major concern for public health because they provide a protective niche that allows for the continuous leaching of bacteria into the water supply. In addition, biofilms enhance the survival of the bacteria by increasing resistance to temperature fluctuations and antimicrobial agents. Currently, there is little known about biofilm formation and regulation by L. pneumophila. Here, we present evidence of a specific gene, bffA, which appears to be involved in the regulation of motility, biofilm formation, cellular replication, and virulence of L. pneumophila. A strain lacking bffA has an enhanced biofilm formation phenotype, forming biofilms that are both faster and thicker than wild type. Additionally, the knockout strain has significantly reduced motility, enhanced uptake into amoebae, and altered growth kinetics on solid media. Our data suggest a potential role for bffA in signaling pathways that govern changes in growth rate and motility in response to environmental conditions.
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9
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Lamprokostopoulou A, Römling U. Yin and Yang of Biofilm Formation and Cyclic di-GMP Signaling of the Gastrointestinal Pathogen Salmonella enterica Serovar Typhimurium. J Innate Immun 2021; 14:275-292. [PMID: 34775379 PMCID: PMC9275015 DOI: 10.1159/000519573] [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] [Received: 05/17/2021] [Accepted: 08/27/2021] [Indexed: 11/24/2022] Open
Abstract
Within the last 60 years, microbiological research has challenged many dogmas such as bacteria being unicellular microorganisms directed by nutrient sources; these investigations produced new dogmas such as cyclic diguanylate monophosphate (cyclic di-GMP) second messenger signaling as a ubiquitous regulator of the fundamental sessility/motility lifestyle switch on the single-cell level. Successive investigations have not yet challenged this view; however, the complexity of cyclic di-GMP as an intracellular bacterial signal, and, less explored, as an extracellular signaling molecule in combination with the conformational flexibility of the molecule, provides endless opportunities for cross-kingdom interactions. Cyclic di-GMP-directed microbial biofilms commonly stimulate the immune system on a lower level, whereas host-sensed cyclic di-GMP broadly stimulates the innate and adaptive immune responses. Furthermore, while the intracellular second messenger cyclic di-GMP signaling promotes bacterial biofilm formation and chronic infections, oppositely, Salmonella Typhimurium cellulose biofilm inside immune cells is not endorsed. These observations only touch on the complexity of the interaction of biofilm microbial cells with its host. In this review, we describe the Yin and Yang interactive concepts of biofilm formation and cyclic di-GMP signaling using S. Typhimurium as an example.
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Affiliation(s)
| | - Ute Römling
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
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10
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Poulin MB, Kuperman LL. Regulation of Biofilm Exopolysaccharide Production by Cyclic Di-Guanosine Monophosphate. Front Microbiol 2021; 12:730980. [PMID: 34566936 PMCID: PMC8461298 DOI: 10.3389/fmicb.2021.730980] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 08/09/2021] [Indexed: 11/25/2022] Open
Abstract
Many bacterial species in nature possess the ability to transition into a sessile lifestyle and aggregate into cohesive colonies, known as biofilms. Within a biofilm, bacterial cells are encapsulated within an extracellular polymeric substance (EPS) comprised of polysaccharides, proteins, nucleic acids, lipids, and other small molecules. The transition from planktonic growth to the biofilm lifecycle provides numerous benefits to bacteria, such as facilitating adherence to abiotic surfaces, evasion of a host immune system, and resistance to common antibiotics. As a result, biofilm-forming bacteria contribute to 65% of infections in humans, and substantially increase the energy and time required for treatment and recovery. Several biofilm specific exopolysaccharides, including cellulose, alginate, Pel polysaccharide, and poly-N-acetylglucosamine (PNAG), have been shown to play an important role in bacterial biofilm formation and their production is strongly correlated with pathogenicity and virulence. In many bacteria the biosynthetic machineries required for assembly of these exopolysaccharides are regulated by common signaling molecules, with the second messenger cyclic di-guanosine monophosphate (c-di-GMP) playing an especially important role in the post-translational activation of exopolysaccharide biosynthesis. Research on treatments of antibiotic-resistant and biofilm-forming bacteria through direct targeting of c-di-GMP signaling has shown promise, including peptide-based treatments that sequester intracellular c-di-GMP. In this review, we will examine the direct role c-di-GMP plays in the biosynthesis and export of biofilm exopolysaccharides with a focus on the mechanism of post-translational activation of these pathways, as well as describe novel approaches to inhibit biofilm formation through direct targeting of c-di-GMP.
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Affiliation(s)
- Myles B Poulin
- Department of Chemistry and Biochemistry, University of Maryland, College Park, College Park, MD, United States
| | - Laura L Kuperman
- Department of Chemistry and Biochemistry, University of Maryland, College Park, College Park, MD, United States
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11
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Singhania RR, Patel AK, Tsai ML, Chen CW, Di Dong C. Genetic modification for enhancing bacterial cellulose production and its applications. Bioengineered 2021; 12:6793-6807. [PMID: 34519629 PMCID: PMC8806912 DOI: 10.1080/21655979.2021.1968989] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Bacterial cellulose (BC) is higher in demand due to its excellent properties which is attributed to its purity and nano size. Komagataeibacter xylinum is a model organism where BC production has been studied in detail because of its higher cellulose production capacity. BC production mechanism shows involvement of a series of sequential reactions with enzymes for biosynthesis of cellulose. It is necessary to know the mechanism to understand the involvement of regulatory proteins which could be the probable targets for genetic modification to enhance or regulate yield of BC and to alter BC properties as well. For the industrial production of BC, controlled synthesis is desired so as to save energy, hence genetic manipulation opens up avenues for upregulating or controlling the cellulose synthesis in the bacterium by targeting genes involved in cellulose biosynthesis. In this review article genetic modification has been presented as a tool to introduce desired changes at genetic level resulting in improved yield or properties. There has been a lack of studies on genetic modification for BC production due to limited availability of information on whole genome and genetic toolkits; however, in last few years, the number of studies has been increased on this aspect as whole genome sequencing of several Komagataeibacter strains are being done. In this review article, we have presented the mechanisms and the targets for genetic modifications in order to achieve desired changes in the BC production titer as well as its characteristics.
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Affiliation(s)
- Reeta Rani Singhania
- Department of Marine Environmental Engineering, National Kaohsiung University of Science and Technology, Kaohsiung City, Taiwan
| | - Anil Kumar Patel
- Department of Marine Environmental Engineering, National Kaohsiung University of Science and Technology, Kaohsiung City, Taiwan
| | - Mei-Ling Tsai
- Department of Seafood Science, National Kaohsiung University of Science and Technology, Kaohsiung City, Taiwan
| | - Chiu-Wen Chen
- Department of Marine Environmental Engineering, National Kaohsiung University of Science and Technology, Kaohsiung City, Taiwan
| | - Cheng Di Dong
- Department of Marine Environmental Engineering, National Kaohsiung University of Science and Technology, Kaohsiung City, Taiwan
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12
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Towards control of cellulose biosynthesis by Komagataeibacter using systems-level and strain engineering strategies: current progress and perspectives. Appl Microbiol Biotechnol 2020; 104:6565-6585. [PMID: 32529377 PMCID: PMC7347698 DOI: 10.1007/s00253-020-10671-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 04/30/2020] [Accepted: 05/04/2020] [Indexed: 12/29/2022]
Abstract
The strains of the Komagataeibacter genus have been shown to be the most efficient bacterial nanocellulose producers. Although exploited for many decades, the studies of these species focused mainly on the optimisation of cellulose synthesis process through modification of culturing conditions in the industrially relevant settings. Molecular physiology of Komagataeibacter was poorly understood and only a few studies explored genetic engineering as a strategy for strain improvement. Only since recently the systemic information of the Komagataeibacter species has been accumulating in the form of omics datasets representing sequenced genomes, transcriptomes, proteomes and metabolomes. Genetic analyses of the mutants generated in the untargeted strain modification studies have drawn attention to other important proteins, beyond those of the core catalytic machinery of the cellulose synthase complex. Recently, modern molecular and synthetic biology tools have been developed which showed the potential for improving targeted strain engineering. Taking the advantage of the gathered knowledge should allow for better understanding of the genotype–phenotype relationship which is necessary for robust modelling of metabolism as well as selection and testing of new molecular engineering targets. In this review, we discuss the current progress in the area of Komagataeibacter systems biology and its impact on the research aimed at scaled-up cellulose synthesis as well as BNC functionalisation.Key points • The accumulated omics datasets advanced the systemic understanding of Komagataeibacter physiology at the molecular level. • Untargeted and targeted strain modification approaches have been applied to improve nanocellulose yield and properties. • The development of modern molecular and synthetic biology tools presents a potential for enhancing targeted strain engineering. • The accumulating omic information should improve modelling of Komagataeibacter’s metabolism as well as selection and testing of new molecular engineering targets. |
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Verderosa AD, Dhouib R, Fairfull-Smith KE, Totsika M. Nitroxide Functionalized Antibiotics Are Promising Eradication Agents against Staphylococcus aureus Biofilms. Antimicrob Agents Chemother 2019; 64:e01685-19. [PMID: 31636066 PMCID: PMC7187575 DOI: 10.1128/aac.01685-19] [Citation(s) in RCA: 15] [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: 08/19/2019] [Accepted: 10/09/2019] [Indexed: 01/10/2023] Open
Abstract
Treatment of biofilm-related Staphylococcus aureus infections represents an important medical challenge worldwide, as biofilms, even those involving drug-susceptible S. aureus strains, are highly refractory to conventional antibiotic therapy. Nitroxides were recently shown to induce the dispersal of Gram-negative biofilms in vitro, but their action against Gram-positive bacterial biofilms remains unknown. Here, we demonstrate that the biofilm dispersal activity of nitroxides extends to S. aureus, a clinically important Gram-positive pathogen. Coadministration of the nitroxide CTEMPO (4-carboxy-2,2,6,6-tetramethylpiperidin-1-yloxyl) with ciprofloxacin significantly improved the biofilm eradication activity of the antibiotic against S. aureus Moreover, covalently linking the nitroxide to the antibiotic moiety further reduced the ciprofloxacin minimal biofilm eradication concentration. Microscopy analysis revealed that fluorescent nitroxide-antibiotic hybrids could penetrate S. aureus biofilms and enter cells localized at the surface and base of the biofilm structure. No toxicity to human cells was observed for the nitroxide CTEMPO or the nitroxide-antibiotic hybrids. Taken together, our results show that nitroxides can mediate the dispersal of Gram-positive biofilms and that dual-acting biofilm eradication antibiotics may provide broad-spectrum therapies for the treatment of biofilm-related infections.
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Affiliation(s)
- Anthony D Verderosa
- School of Chemistry, Physics, and Mechanical Engineering, Queensland University of Technology, Brisbane, Queensland, Australia
- Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
- School of Biomedical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Rabeb Dhouib
- Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
- School of Biomedical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Kathryn E Fairfull-Smith
- School of Chemistry, Physics, and Mechanical Engineering, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Makrina Totsika
- Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
- School of Biomedical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia
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14
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Suchanek VM, Esteban-López M, Colin R, Besharova O, Fritz K, Sourjik V. Chemotaxis and cyclic-di-GMP signalling control surface attachment of Escherichia coli. Mol Microbiol 2019; 113:728-739. [PMID: 31793092 DOI: 10.1111/mmi.14438] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 11/28/2019] [Indexed: 12/18/2022]
Abstract
Attachment to surfaces is an important early step during bacterial infection and during formation of submerged biofilms. Although flagella-mediated motility is known to be important for attachment of Escherichia coli and other bacteria, implications of motility regulation by cellular signalling remain to be understood. Here, we show that motility largely promotes attachment of E. coli, including that mediated by type 1 fimbriae, by allowing cells to reach, get hydrodynamically trapped at and explore the surface. Inactivation or inhibition of the chemotaxis signalling pathway improves attachment by suppressing cell reorientations and thereby increasing surface residence times. The attachment is further enhanced by deletion of genes encoding the cyclic diguanosine monophosphate (c-di-GMP)-dependent flagellar brake YcgR or the diguanylate cyclase DgcE. Such increased attachment in absence of c-di-GMP signalling is in contrast to its commonly accepted function as a positive regulator of the sessile state. It is apparently due to the increased swimming speed of E. coli in absence of YcgR-mediated motor control, which strengthens adhesion mediated by the type 1 fimbriae. Thus, both signalling networks that regulate motility of E. coli also control its engagement with both biotic and abiotic surfaces, which has likely implications for infection and biofilm formation.
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Affiliation(s)
- Verena Maria Suchanek
- Max Planck Institute for Terrestrial Microbiology & LOEWE Center for Synthetic Microbiology (SYNMIKRO), Marburg, Germany.,Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), Heidelberg, Germany
| | - María Esteban-López
- Max Planck Institute for Terrestrial Microbiology & LOEWE Center for Synthetic Microbiology (SYNMIKRO), Marburg, Germany
| | - Rémy Colin
- Max Planck Institute for Terrestrial Microbiology & LOEWE Center for Synthetic Microbiology (SYNMIKRO), Marburg, Germany
| | - Olga Besharova
- Max Planck Institute for Terrestrial Microbiology & LOEWE Center for Synthetic Microbiology (SYNMIKRO), Marburg, Germany
| | - Kirstin Fritz
- Max Planck Institute for Terrestrial Microbiology & LOEWE Center for Synthetic Microbiology (SYNMIKRO), Marburg, Germany
| | - Victor Sourjik
- Max Planck Institute for Terrestrial Microbiology & LOEWE Center for Synthetic Microbiology (SYNMIKRO), Marburg, Germany.,Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), Heidelberg, Germany
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Jacek P, Dourado F, Gama M, Bielecki S. Molecular aspects of bacterial nanocellulose biosynthesis. Microb Biotechnol 2019; 12:633-649. [PMID: 30883026 PMCID: PMC6559022 DOI: 10.1111/1751-7915.13386] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 02/03/2019] [Accepted: 02/08/2019] [Indexed: 11/27/2022] Open
Abstract
Bacterial nanocellulose (BNC) produced by aerobic bacteria is a biopolymer with sophisticated technical properties. Although the potential for economically relevant applications is huge, the cost of BNC still limits its application to a few biomedical devices and the edible product Nata de Coco, made available by traditional fermentation methods in Asian countries. Thus, a wider economic relevance of BNC is still dependent on breakthrough developments on the production technology. On the other hand, the development of modified strains able to overproduce BNC with new properties - e.g. porosity, density of fibres crosslinking, mechanical properties, etc. - will certainly allow to overcome investment and cost production issues and enlarge the scope of BNC applications. This review discusses current knowledge about the molecular basis of BNC biosynthesis, its regulations and, finally, presents a perspective on the genetic modification of BNC producers made possible by the new tools available for genetic engineering.
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Affiliation(s)
- Paulina Jacek
- Institute of Technical BiochemistryLodz University of Technology4/10 Stefanowskiego Str90‐924LodzPoland
| | - Fernando Dourado
- Centre of Biological EngineeringUniversity of MinhoCampus de Gualtar4710‐057BragaPortugal
| | - Miguel Gama
- Centre of Biological EngineeringUniversity of MinhoCampus de Gualtar4710‐057BragaPortugal
| | - Stanisław Bielecki
- Institute of Technical BiochemistryLodz University of Technology4/10 Stefanowskiego Str90‐924LodzPoland
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Wilt IK, Hari TPA, Wuest WM. Hijacking the Bacterial Circuitry of Biofilm Processes via Chemical "Hot-Wiring": An Under-explored Avenue for Therapeutic Development. ACS Infect Dis 2019; 5:789-795. [PMID: 31001972 DOI: 10.1021/acsinfecdis.9b00104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Biofilm-associated infections are linked to chronic and recurring illnesses. These infections are often not susceptible to current antibiotic treatments because of the protective exocellular matrix and subpopulations of dormant or "persister" cells. Targeting bacterial circuitry involved in biofilm formation, including two-component systems, quorum sensing, polysaccharide structural integrity, and cyclic nucleotide signaling pathways, has the potential to expand the existing arsenal of therapeutics, thus catalyzing a second golden age of antibiotic development.
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Affiliation(s)
- Ingrid K. Wilt
- Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
| | - Taylor P. A. Hari
- Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
| | - William M. Wuest
- Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
- Emory Antibiotic Resistance Center, Emory University School of Medicine, 201 Dowman Drive, Atlanta, Georgia 30322, United States
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DncV Synthesizes Cyclic GMP-AMP and Regulates Biofilm Formation and Motility in Escherichia coli ECOR31. mBio 2019; 10:mBio.02492-18. [PMID: 30837338 PMCID: PMC6401482 DOI: 10.1128/mbio.02492-18] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The ability of bacteria to sense and respond to environmental signals is critical for survival. Bacteria use cyclic dinucleotides as second messengers to regulate a number of physiological processes, such as the fundamental life style transition between motility and sessility (biofilm formation). cGAMP, which is synthesized by a dinucleotide cyclase called DncV, is a newly discovered second messenger involved in virulence and chemotaxis in the Vibrio cholerae biovar El Tor causing the current 7th cholera pandemic. However, to what extent cGAMP exists and participates in physiological processes in other bacteria is still unknown. In this study, we found an elevated cGAMP level to possibly regulate biofilm formation and motility in the animal commensal E. coli strain ECOR31. Thus, we detected a novel role for cGAMP signaling in regulation of physiological processes other than those previously reported in proteobacterial species. Cyclic dinucleotides (cDNs) act as intracellular second messengers, modulating bacterial physiology to regulate the fundamental life style transition between motility and sessility commonly known as biofilm formation. Cyclic GMP-AMP (cGAMP), synthesized by the dinucleotide cyclase DncV, is a newly discovered cDN second messenger involved in virulence and chemotaxis in Vibrio cholerae O1 biovar El Tor. Here we report a novel role for horizontally transferred DncV in cGAMP production and regulation of biofilm formation and motility in the animal commensal strain Escherichia coli ECOR31. ECOR31 expresses a semiconstitutive temperature-independent rdar (red, dry, and rough) morphotype on Congo red agar plates characterized by the extracellular matrix components cellulose and curli fimbriae which requires activation by the major biofilm regulator CsgD and cyclic di-GMP signaling. In contrast, C-terminal His-tagged DncV negatively regulates the rdar biofilm morphotype and cell aggregation via downregulation of csgD mRNA steady-state level. Furthermore, DncV sequentially promotes and inhibits adhesion to the abiotic surface after 24 h and 48 h of growth, respectively. DncV also suppresses swimming and swarming motility posttranscriptional of the class 1 flagellum regulon gene flhD. Purified DncV produced different cDNs, cyclic di-GMP, cyclic di-AMP, an unknown product(s), and the dominant species 3′3′-cGAMP. In vivo, only the 3′3′-cGAMP concentration was elevated upon short-term overexpression of dncV, making this work a first report on cGAMP production in E. coli. Regulation of rdar biofilm formation and motility upon overexpression of untagged DncV in combination with three adjacent cotransferred gene products suggests a novel temperature-dependent cGAMP signaling module in E. coli ECOR31.
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18
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Ryngajłło M, Kubiak K, Jędrzejczak-Krzepkowska M, Jacek P, Bielecki S. Comparative genomics of the Komagataeibacter strains-Efficient bionanocellulose producers. Microbiologyopen 2018; 8:e00731. [PMID: 30365246 PMCID: PMC6528568 DOI: 10.1002/mbo3.731] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 08/13/2018] [Accepted: 08/21/2018] [Indexed: 12/21/2022] Open
Abstract
Komagataeibacter species are well-recognized bionanocellulose (BNC) producers. This bacterial genus, formerly assigned to Gluconacetobacter, is known for its phenotypic diversity manifested by strain-dependent carbon source preference, BNC production rate, pellicle structure, and strain stability. Here, we performed a comparative study of nineteen Komagataeibacter genomes, three of which were newly contributed in this work. We defined the core genome of the genus, clarified phylogenetic relationships among strains, and provided genetic evidence for the distinction between the two major clades, the K. xylinus and the K. hansenii. We found genomic traits, which likely contribute to the phenotypic diversity between the Komagataeibacter strains. These features include genome flexibility, carbohydrate uptake and regulation of its metabolism, exopolysaccharides synthesis, and the c-di-GMP signaling network. In addition, this work provides a comprehensive functional annotation of carbohydrate metabolism pathways, such as those related to glucose, glycerol, acetan, levan, and cellulose. Findings of this multi-genomic study expand understanding of the genetic variation within the Komagataeibacter genus and facilitate exploiting of its full potential for bionanocellulose production at the industrial scale.
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Affiliation(s)
- Małgorzata Ryngajłło
- Institute of Technical Biochemistry, Lodz University of Technology, Lodz, Poland
| | - Katarzyna Kubiak
- Institute of Technical Biochemistry, Lodz University of Technology, Lodz, Poland
| | | | - Paulina Jacek
- Institute of Technical Biochemistry, Lodz University of Technology, Lodz, Poland
| | - Stanisław Bielecki
- Institute of Technical Biochemistry, Lodz University of Technology, Lodz, Poland
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19
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Synthetic small molecules as anti-biofilm agents in the struggle against antibiotic resistance. Eur J Med Chem 2018; 161:154-178. [PMID: 30347328 DOI: 10.1016/j.ejmech.2018.10.036] [Citation(s) in RCA: 105] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 10/10/2018] [Accepted: 10/15/2018] [Indexed: 01/24/2023]
Abstract
Biofilm formation significantly contributes to microbial survival in hostile environments and it is currently considered a key virulence factor for pathogens responsible for serious chronic infections. In the last decade many efforts have been made to identify new agents able to modulate bacterial biofilm life cycle, and many compounds have shown interesting activities in inhibiting biofilm formation or in dispersing pre-formed biofilms. However, only a few of these compounds were tested using in vivo models for their clinical significance. Contrary to conventional antibiotics, most of the anti-biofilm compounds act as anti-virulence agents as they do not affect bacterial growth. In this review we selected the most relevant literature of the last decade, focusing on the development of synthetic small molecules able to prevent bacterial biofilm formation or to eradicate pre-existing biofilms of clinically relevant Gram-positive and Gram-negative pathogens. In addition, we provide a comprehensive list of the possible targets to counteract biofilm formation and development, as well as a detailed discussion the advantages and disadvantages of the different current biofilm-targeting strategies.
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20
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PP4397/FlgZ provides the link between PP2258 c-di-GMP signalling and altered motility in Pseudomonas putida. Sci Rep 2018; 8:12205. [PMID: 30111852 PMCID: PMC6093933 DOI: 10.1038/s41598-018-29785-w] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 07/18/2018] [Indexed: 01/01/2023] Open
Abstract
Bacteria swim and swarm using rotating flagella that are driven by a membrane-spanning motor complex. Performance of the flagella motility apparatus is modulated by the chemosensory signal transduction system to allow navigation through physico-chemical gradients - a process that can be fine-tuned by the bacterial second messenger c-di-GMP. We have previously analysed the Pseudomonas putida signalling protein PP2258 that has the capacity to both synthesize and degrade c-di-GMP. A PP2258 null mutant displays reduced motility, implicating the c-di-GMP signal originating from this protein in control of P. putida motility. In Escherichia coli and Salmonella, the PilZ-domain protein YcgR mediates c-di-GMP responsive control of motility through interaction with the flagellar motors. Here we provide genetic evidence that the P. putida protein PP4397 (also known as FlgZ), despite low sequence homology and a different genomic context to YcgR, functions as a c-di-GMP responsive link between the signal arising from PP2258 and alterations in swimming and swarming motility in P. putida.
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21
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Abstract
Bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP) is an important signaling molecule for community behavior control, cell morphogenesis, and virulence in bacteria. In addition to protein effectors, this second messenger binds RNA molecules that act as riboswitches to control target gene expression. In this chapter, we describe a method for experimental validation of the functionality of c-di-GMP-responsive riboswitches and the analysis of c-di-GMP control of target gene expression by qRT-PCR and Northern blot. This procedure can be used for the studies of in silico-predicted riboswitch candidates, as well as a targeted experimental approach for exploring the data from next-generation sequencing. The examples on the analysis of type I and type II c-di-GMP-responsive riboswitches in Clostridium difficile are provided to illustrate the application of the method.
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Affiliation(s)
- Johann Peltier
- Laboratoire Pathogenèse des Bactéries Anaérobies, Institut Pasteur, 25 rue du Dr Roux, 75724, Paris Cedex 15, France.,Université Paris Diderot, Sorbonne Paris Cité, 25 rue du Dr Roux, 75724, Paris Cedex 15, France
| | - Olga Soutourina
- Laboratoire Pathogenèse des Bactéries Anaérobies, Institut Pasteur, 25 rue du Dr Roux, 75724, Paris Cedex 15, France. .,Université Paris Diderot, Sorbonne Paris Cité, 25 rue du Dr Roux, 75724, Paris Cedex 15, France. .,Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette Cedex, France.
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22
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Vila J, Sáez-López E, Johnson JR, Römling U, Dobrindt U, Cantón R, Giske CG, Naas T, Carattoli A, Martínez-Medina M, Bosch J, Retamar P, Rodríguez-Baño J, Baquero F, Soto SM. Escherichia coli: an old friend with new tidings. FEMS Microbiol Rev 2018; 40:437-463. [PMID: 28201713 DOI: 10.1093/femsre/fuw005] [Citation(s) in RCA: 180] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 09/23/2015] [Accepted: 02/04/2016] [Indexed: 12/16/2022] Open
Abstract
Escherichia coli is one of the most-studied microorganisms worldwide but its characteristics are continually changing. Extraintestinal E. coli infections, such as urinary tract infections and neonatal sepsis, represent a huge public health problem. They are caused mainly by specialized extraintestinal pathogenic E. coli (ExPEC) strains that can innocuously colonize human hosts but can also cause disease upon entering a normally sterile body site. The virulence capability of such strains is determined by a combination of distinctive accessory traits, called virulence factors, in conjunction with their distinctive phylogenetic background. It is conceivable that by developing interventions against the most successful ExPEC lineages or their key virulence/colonization factors the associated burden of disease and health care costs could foreseeably be reduced in the future. On the other hand, one important problem worldwide is the increase of antimicrobial resistance shown by bacteria. As underscored in the last WHO global report, within a wide range of infectious agents including E. coli, antimicrobial resistance has reached an extremely worrisome situation that ‘threatens the achievements of modern medicine’. In the present review, an update of the knowledge about the pathogenicity, antimicrobial resistance and clinical aspects of this ‘old friend’ was presented.
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Affiliation(s)
- J Vila
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain
- Department of Clinical Microbiology, Hospital Clinic, Universitat de Barcelona, Barcelona, Spain
- Spanish Network for Research in Infectious Diseases (REIPI), Instituto de Salud Carlos III, Madrid, Spain
| | - E Sáez-López
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain
| | - J R Johnson
- VA Medical Center, Minneapolis, MN, USA, and University of Minnesota, Minneapolis, MN, USA
| | - U Römling
- Karolinska Institute, Stockholm, Sweden
| | - U Dobrindt
- Institute of Hygiene, University of Münster, Münster, Germany
| | - R Cantón
- Servicio de Microbiología, Hospital Universitario Ramón y Cajal and Instituto de Investigación Sanitaria (IRYCIS), Madrid, Spain
- Spanish Network for Research in Infectious Diseases (REIPI), Instituto de Salud Carlos III, Madrid, Spain
| | - C G Giske
- Karolinska Institute, Stockholm, Sweden
| | - T Naas
- Hôpital de Bicêtre, Université Paris Sud, Le Kremlin-Bicêtre, France
| | - A Carattoli
- Department of infectious, parasitic and immune-mediated diseases, Istituto Superiore di Sanità, Rome, Italy
| | - M Martínez-Medina
- Laboratory of Molecular Microbiology, Department of Biology, University of Girona, Girona, Spain
| | - J Bosch
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain
- Department of Clinical Microbiology, Hospital Clinic, Universitat de Barcelona, Barcelona, Spain
| | - P Retamar
- Unidad Clínica de Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Hospitales Universitarios Virgen Macarena y Virgen del Rocío, Departamento de Medicina, Universidad de Sevilla, Seville, Spain
| | - J Rodríguez-Baño
- Unidad Clínica de Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Hospitales Universitarios Virgen Macarena y Virgen del Rocío, Departamento de Medicina, Universidad de Sevilla, Seville, Spain
- Spanish Network for Research in Infectious Diseases (REIPI), Instituto de Salud Carlos III, Madrid, Spain
| | - F Baquero
- Servicio de Microbiología, Hospital Universitario Ramón y Cajal and Instituto de Investigación Sanitaria (IRYCIS), Madrid, Spain
| | - S M Soto
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain
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Castiblanco LF, Sundin GW. Cellulose production, activated by cyclic di-GMP through BcsA and BcsZ, is a virulence factor and an essential determinant of the three-dimensional architectures of biofilms formed by Erwinia amylovora Ea1189. MOLECULAR PLANT PATHOLOGY 2018; 19:90-103. [PMID: 27753193 PMCID: PMC6638026 DOI: 10.1111/mpp.12501] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 10/10/2016] [Accepted: 10/13/2016] [Indexed: 05/04/2023]
Abstract
Bacterial biofilms are multicellular aggregates encased in an extracellular matrix mainly composed of exopolysaccharides (EPSs), protein and nucleic acids, which determines the architecture of the biofilm. Erwinia amylovora Ea1189 forms a biofilm inside the xylem of its host, which results in vessel plugging and water transport impairment. The production of the EPSs amylovoran and levan is critical for the formation of a mature biofilm. In addition, cyclic dimeric GMP (c-di-GMP) has been reported to positively regulate amylovoran biosynthesis and biofilm formation in E. amylovora Ea1189. In this study, we demonstrate that cellulose is synthesized by E. amylovora Ea1189 and is a major modulator of the three-dimensional characteristics of biofilms formed by this bacterium, and also contributes to virulence during systemic host invasion. In addition, we demonstrate that the activation of cellulose biosynthesis in E. amylovora is a c-di-GMP-dependent process, through allosteric binding to the cellulose catalytic subunit BcsA. We also report that the endoglucanase BcsZ is a key player in c-di-GMP activation of cellulose biosynthesis. Our results provide evidence of the complex composition of the extracellular matrix produced by E. amylovora and the implications of cellulose biosynthesis in shaping the architecture of the biofilm and in the expression of one of the main virulence phenotypes of this pathogen.
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Affiliation(s)
- Luisa F. Castiblanco
- Department of Plant, Soil and Microbial Sciences and Center for Microbial PathogenesisMichigan State UniversityEast LansingMI48824USA
| | - George W. Sundin
- Department of Plant, Soil and Microbial Sciences and Center for Microbial PathogenesisMichigan State UniversityEast LansingMI48824USA
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24
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The stringent response promotes biofilm dispersal in Pseudomonas putida. Sci Rep 2017; 7:18055. [PMID: 29273811 PMCID: PMC5741744 DOI: 10.1038/s41598-017-18518-0] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 12/12/2017] [Indexed: 01/08/2023] Open
Abstract
Biofilm dispersal is a genetically programmed response enabling bacterial cells to exit the biofilm in response to particular physiological or environmental conditions. In Pseudomonas putida biofilms, nutrient starvation triggers c-di-GMP hydrolysis by phosphodiesterase BifA, releasing inhibition of protease LapG by the c-di-GMP effector protein LapD, and resulting in proteolysis of the adhesin LapA and the subsequent release of biofilm cells. Here we demonstrate that the stringent response, a ubiquitous bacterial stress response, is accountable for relaying the nutrient stress signal to the biofilm dispersal machinery. Mutants lacking elements of the stringent response - (p)ppGpp sythetases [RelA and SpoT] and/or DksA - were defective in biofilm dispersal. Ectopic (p)ppGpp synthesis restored biofilm dispersal in a ∆relA ∆spoT mutant. In vivo gene expression analysis showed that (p)ppGpp positively regulates transcription of bifA, and negatively regulates transcription of lapA and the lapBC, and lapE operons, encoding a LapA-specific secretion system. Further in vivo and in vitro characterization revealed that the PbifA promoter is dependent on the flagellar σ factor FliA, and positively regulated by ppGpp and DksA. Our results indicate that the stringent response stimulates biofilm dispersal under nutrient limitation by coordinately promoting LapA proteolysis and preventing de novo LapA synthesis and secretion.
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25
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Burns JL, Jariwala PB, Rivera S, Fontaine BM, Briggs L, Weinert EE. Oxygen-Dependent Globin Coupled Sensor Signaling Modulates Motility and Virulence of the Plant Pathogen Pectobacterium carotovorum. ACS Chem Biol 2017; 12:2070-2077. [PMID: 28612602 DOI: 10.1021/acschembio.7b00380] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Bacterial pathogens utilize numerous signals to identify the presence of their host and coordinate changes in gene expression that allow for infection. Within plant pathogens, these signals typically include small molecules and/or proteins from their plant hosts and bacterial quorum sensing molecules to ensure sufficient bacterial cell density for successful infection. In addition, bacteria use environmental signals to identify conditions when the host defenses are weakened and potentially to signal entry into an appropriate host/niche for infection. A globin coupled sensor protein (GCS), termed PccGCS, within the soft rot bacterium Pectobacterium carotovorum ssp. carotovorum WPP14 has been identified as an O2 sensor and demonstrated to alter virulence factor excretion and control motility, with deletion of PccGCS resulting in decreased rotting of a potato host. Using small molecules that modulate bacterial growth and quorum sensing, PccGCS signaling also has been shown to modulate quorum sensing pathways, resulting in the PccGCS deletion strain being more sensitive to plant-derived phenolic acids, which can function as quorum sensing inhibitors, and exhibiting increased N-acylhomoserine lactone (AHL) production. These findings highlight a role for GCS proteins in controlling key O2-dependent phenotypes of pathogenic bacteria and suggest that modulating GCS signaling to limit P. carotovorum motility may provide a means to decrease rotting of plant hosts.
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Affiliation(s)
- Justin L. Burns
- Department of Chemistry, Emory University, 1515
Dickey Drive, Atlanta, Georgia 30322, United States
| | - Parth B. Jariwala
- Department of Chemistry, Emory University, 1515
Dickey Drive, Atlanta, Georgia 30322, United States
| | - Shannon Rivera
- Department of Chemistry, Emory University, 1515
Dickey Drive, Atlanta, Georgia 30322, United States
| | - Benjamin M. Fontaine
- Department of Chemistry, Emory University, 1515
Dickey Drive, Atlanta, Georgia 30322, United States
| | - Laura Briggs
- Department of Chemistry, Emory University, 1515
Dickey Drive, Atlanta, Georgia 30322, United States
| | - Emily E. Weinert
- Department of Chemistry, Emory University, 1515
Dickey Drive, Atlanta, Georgia 30322, United States
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Hossain S, Nisbett LM, Boon EM. Discovery of Two Bacterial Nitric Oxide-Responsive Proteins and Their Roles in Bacterial Biofilm Regulation. Acc Chem Res 2017; 50:1633-1639. [PMID: 28605194 PMCID: PMC5654536 DOI: 10.1021/acs.accounts.7b00095] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Bacterial biofilms form when bacteria adhere to a surface and produce an exopolysaccharide matrix ( Costerton Science 1999 , 284 , 1318 ; Davies Science 1998 , 280 , 295 ; Flemming Nat. Rev. Microbiol. 2010 , 8 , 623 ). Because biofilms are resistant to antibiotics, they are problematic in many aspects of human health and welfare, causing, for instance, persistent fouling of medical implants such as catheters and artificial joints ( Brunetto Chimia 2008 , 62 , 249 ). They are responsible for chronic infections in the lungs of cystic fibrosis patients and in open wounds, such as those associated with burns and diabetes. They are also a major contributor to hospital-acquired infections ( Sievert Infec. Control Hosp. Epidemiol. 2013 , 34 , 1 ; Tatterson Front. Biosci. 2001 , 6 , D890 ). It has been hypothesized that effective methods of biofilm control will have widespread application ( Landini Appl. Microbiol. Biotechnol. 2010 , 86 , 813 ). A promising strategy is to target the mechanisms that drive biofilm dispersal, because dispersal results in biofilm removal and in the restoration of antibiotic sensitivity. First documented in Nitrosomonas europaea ( Schmidt J. Bacteriol. 2004 , 186 , 2781 ) and the cystic fibrosis-associated pathogen Pseudomonas aeruginosa ( Barraud J. Bacteriol. 2006 , 188 , 7344 ; J. Bacteriol. 2009 , 191 , 7333 ), regulation of biofilm formation by nanomolar levels of the diatomic gas nitric oxide (NO) has now been documented in numerous bacteria ( Barraud Microb. Biotechnol. 2009 , 2 , 370 ; McDougald Nat. Rev. Microbiol. 2012 , 10 , 39 ; Arora Biochemistry 2015 , 54 , 3717 ; Barraud Curr. Pharm. Des. 2015 , 21 , 31 ). NO-mediated pathways are, therefore, promising candidates for biofilm regulation. Characterization of the NO sensors and NO-regulated signaling pathways should allow for rational manipulation of these pathways for therapeutic applications. Several laboratories, including our own, have shown that a class of NO sensors called H-NOX (heme-nitric oxide or oxygen binding domain) affects biofilm formation by regulating intracellular cyclic di-GMP concentrations and quorum sensing ( Arora Biochemistry 2015 , 54 , 3717 ; Plate Trends Biochem. Sci. 2013 , 38 , 566 ; Nisbett Biochemistry 2016 , 55 , 4873 ). Many bacteria that respond to NO do not encode an hnoX gene, however. My laboratory has now discovered an additional family of bacterial NO sensors, called NosP (nitric oxide sensing protein). Importantly, NosP domains are widely conserved in bacteria, especially Gram-negative bacteria, where they are encoded as fusions with or in close chromosomal proximity to histidine kinases or cyclic di-GMP synthesis or phosphodiesterase enzyme, consistent with signaling. In this Account, we briefly review NO and H-NOX signaling in bacterial biofilms, describe our discovery of the NosP family, and provide support for its role in biofilm regulation in Pseudomonas aeruginosa, Vibrio cholerae, Legionella pneumophila, and Shewanella oneidensis.
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Affiliation(s)
- Sajjad Hossain
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States
| | - Lisa-Marie Nisbett
- Graduate Program in Biochemistry and Structural Biology, Stony Brook University, Stony Brook, New York 11794-5215, United States
| | - Elizabeth M. Boon
- Graduate Program in Biochemistry and Structural Biology, Stony Brook University, Stony Brook, New York 11794-5215, United States
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States
- Institute of Chemical Biology & Drug Discovery, Stony Brook University, Stony Brook, New York 11794-3400, United States
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Rossi E, Cimdins A, Lüthje P, Brauner A, Sjöling Å, Landini P, Römling U. "It's a gut feeling" - Escherichia coli biofilm formation in the gastrointestinal tract environment. Crit Rev Microbiol 2017; 44:1-30. [PMID: 28485690 DOI: 10.1080/1040841x.2017.1303660] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Escherichia coli can commonly be found, either as a commensal, probiotic or a pathogen, in the human gastrointestinal (GI) tract. Biofilm formation and its regulation is surprisingly variable, although distinct regulatory pattern of red, dry and rough (rdar) biofilm formation arise in certain pathovars and even clones. In the GI tract, environmental conditions, signals from the host and from commensal bacteria contribute to shape E. coli biofilm formation within the multi-faceted multicellular communities in a complex and integrated fashion. Although some major regulatory networks, adhesion factors and extracellular matrix components constituting E. coli biofilms have been recognized, these processes have mainly been characterized in vitro and in the context of interaction of E. coli strains with intestinal epithelial cells. However, direct observation of E. coli cells in situ, and the vast number of genes encoding surface appendages on the core or accessory genome of E. coli suggests the complexity of the biofilm process to be far from being fully understood. In this review, we summarize biofilm formation mechanisms of commensal, probiotic and pathogenic E. coli in the context of the gastrointestinal tract.
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Affiliation(s)
- Elio Rossi
- a Department of Biosciences , Università degli Studi di Milano , Milan , Italy.,b Novo Nordisk Center for Biosustainabiliy , Technical University of Denmark , Kgs. Lyngby , Denmark
| | - Annika Cimdins
- c Department of Microbiology, Tumor and Cell Biology (MTC) , Karolinska Institutet , Stockholm , Sweden.,d Institute of Hygiene, University of Münster , Münster , Germany
| | - Petra Lüthje
- c Department of Microbiology, Tumor and Cell Biology (MTC) , Karolinska Institutet , Stockholm , Sweden.,e Division of Clinical Microbiology, Department of Laboratory Medicine , Karolinska Institutet and Karolinska University Hospital Huddinge , Stockholm , Sweden
| | - Annelie Brauner
- c Department of Microbiology, Tumor and Cell Biology (MTC) , Karolinska Institutet , Stockholm , Sweden
| | - Åsa Sjöling
- c Department of Microbiology, Tumor and Cell Biology (MTC) , Karolinska Institutet , Stockholm , Sweden
| | - Paolo Landini
- a Department of Biosciences , Università degli Studi di Milano , Milan , Italy
| | - Ute Römling
- c Department of Microbiology, Tumor and Cell Biology (MTC) , Karolinska Institutet , Stockholm , Sweden
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Schmid N, Suppiger A, Steiner E, Pessi G, Kaever V, Fazli M, Tolker-Nielsen T, Jenal U, Eberl L. High intracellular c-di-GMP levels antagonize quorum sensing and virulence gene expression in Burkholderia cenocepacia H111. MICROBIOLOGY-SGM 2017; 163:754-764. [PMID: 28463102 DOI: 10.1099/mic.0.000452] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The opportunistic human pathogen Burkholderia cenocepacia H111 uses two chemically distinct signal molecules for controlling gene expression in a cell density-dependent manner: N-acyl-homoserine lactones (AHLs) and cis-2-dodecenoic acid (BDSF). Binding of BDSF to its cognate receptor RpfR lowers the intracellular c-di-GMP level, which in turn leads to differential expression of target genes. In this study we analysed the transcriptional profile of B. cenocepacia H111 upon artificially altering the cellular c-di-GMP level. One hundred and eleven genes were shown to be differentially expressed, 96 of which were downregulated at a high c-di-GMP concentration. Our analysis revealed that the BDSF, AHL and c-di-GMP regulons overlap for the regulation of 24 genes and that a high c-di-GMP level suppresses expression of AHL-regulated genes. Phenotypic analyses confirmed changes in the expression of virulence factors, the production of AHL signal molecules and the biosynthesis of different biofilm matrix components upon altered c-di-GMP levels. We also demonstrate that the intracellular c-di-GMP level determines the virulence of B. cenocepacia to Caenorhabditis elegans and Galleria mellonella.
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Affiliation(s)
- Nadine Schmid
- Institute of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Angela Suppiger
- Institute of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Elisabeth Steiner
- Institute of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Gabriella Pessi
- Institute of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Volkhard Kaever
- Research Core Unit Metabolomics, Hannover Medical School, Hannover, Germany
| | - Mustafa Fazli
- Department of Biology, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Tim Tolker-Nielsen
- Costerton Biofilm Center, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Urs Jenal
- Focal Area of Infection Biology, Biozentrum, University of Basel, Basel, Switzerland
| | - Leo Eberl
- Institute of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
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Soutourina O. RNA-based control mechanisms of Clostridium difficile. Curr Opin Microbiol 2017; 36:62-68. [PMID: 28214735 DOI: 10.1016/j.mib.2017.01.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 11/28/2016] [Accepted: 01/08/2017] [Indexed: 01/05/2023]
Abstract
Clostridium difficile (CD)-associated diarrhoea is currently the most prevalent nosocomial diarrhoea worldwide. Many characteristics of CD pathogenicity remain poorly understood. Recent data strongly indicate the importance of an RNA network for the control of gene expression in CD. More than 200 regulatory RNAs have been identified by deep sequencing and targeted approaches, including Hfq-dependent trans riboregulators, cis-antisense RNAs, CRISPR RNAs, and c-di-GMP-responsive riboswitches. These regulatory RNAs are involved in the control of major processes in the CD infection cycle, for example motility, biofilm formation, adhesion, sporulation, stress response, and defence against bacteriophages. We will discuss recent advances in elucidation of the original features of RNA-based mechanisms in this important enteropathogen. This knowledge may pave the way for further discoveries in this emergent field.
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Affiliation(s)
- Olga Soutourina
- Laboratoire Pathogenèse des Bactéries Anaérobies, Institut Pasteur, 25 rue du Dr Roux, 75724 Paris Cedex 15, France; Université Paris Diderot, Sorbonne Paris Cité, Cellule Pasteur, 25 rue du Dr Roux, 75724 Paris Cedex 15, France; Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France.
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Moleleki LN, Pretorius RG, Tanui CK, Mosina G, Theron J. A quorum sensing-defective mutant of Pectobacterium carotovorum ssp. brasiliense 1692 is attenuated in virulence and unable to occlude xylem tissue of susceptible potato plant stems. MOLECULAR PLANT PATHOLOGY 2017; 18:32-44. [PMID: 26788858 PMCID: PMC6638202 DOI: 10.1111/mpp.12372] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Revised: 01/15/2016] [Accepted: 01/15/2016] [Indexed: 05/13/2023]
Abstract
Pectobacterium carotovorum ssp. brasiliense 1692 (Pcb1692) is an important emerging pathogen of potatoes causing blackleg in the field and soft rot during post-harvest storage. Blackleg diseases involve the bacterial colonization of vascular tissue and the formation of aggregates, also known as biofilms. To understand the role of quorum sensing in vascular colonization by Pcb1692, we generated a Pcb1692ΔexpI mutant strain. Inactivation of expI led to the reduced production of plant cell wall-degrading enzymes (PCWDEs), the inability to produce acyl homoserine lactone (AHL) and reduced virulence in potato tubers and stems. Complementation of the mutant strain with the wild-type expI gene in trans successfully restored AHL and PCWDE production as well as virulence. Transmission electron microscopy and in vitro motility assays demonstrated hyperpiliation and loss of flagella and swimming motility in the mutant strain compared with the wild-type Pcb1692. Furthermore, we noted that, in the early stages of infection, Pcb1692 wild-type cells had intact flagella which were shed at the later stages of infection. Confocal laser microscopy of PcbΔexpI-inoculated plants showed that the mutant strain tended to aggregate in intercellular spaces, but was unable to transit to xylem tissue. On the contrary, the wild-type strain was often observed forming aggregates within xylem tissue of potato stems. Gene expression analyses confirmed that flagella are part of the quorum sensing regulon, whereas fimbriae and pili appear to be negatively regulated by quorum sensing. The relative expression levels of other important putative virulence genes, such as those encoding different groups of PCWDEs, were down-regulated in the mutant compared with the wild-type strain.
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Affiliation(s)
- Lucy Novungayo Moleleki
- Forestry, Agriculture and Biotechnology Institute, University of PretoriaLunnon RoadPretoriaSouth Africa0028
- Department of Microbiology and Plant PathologyUniversity of PretoriaLunnon RoadPretoriaSouth Africa0028
| | - Rudolph Gustav Pretorius
- Forestry, Agriculture and Biotechnology Institute, University of PretoriaLunnon RoadPretoriaSouth Africa0028
| | - Collins Kipngetich Tanui
- Forestry, Agriculture and Biotechnology Institute, University of PretoriaLunnon RoadPretoriaSouth Africa0028
| | - Gabolwelwe Mosina
- Forestry, Agriculture and Biotechnology Institute, University of PretoriaLunnon RoadPretoriaSouth Africa0028
| | - Jacques Theron
- Department of Microbiology and Plant PathologyUniversity of PretoriaLunnon RoadPretoriaSouth Africa0028
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31
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Jiménez-Fernández A, López-Sánchez A, Jiménez-Díaz L, Navarrete B, Calero P, Platero AI, Govantes F. Complex Interplay between FleQ, Cyclic Diguanylate and Multiple σ Factors Coordinately Regulates Flagellar Motility and Biofilm Development in Pseudomonas putida. PLoS One 2016; 11:e0163142. [PMID: 27636892 PMCID: PMC5026340 DOI: 10.1371/journal.pone.0163142] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Accepted: 09/02/2016] [Indexed: 01/01/2023] Open
Abstract
Most bacteria alternate between a free living planktonic lifestyle and the formation of structured surface-associated communities named biofilms. The transition between these two lifestyles requires a precise and timely regulation of the factors involved in each of the stages that has been likened to a developmental process. Here we characterize the involvement of the transcriptional regulator FleQ and the second messenger cyclic diguanylate in the coordinate regulation of multiple functions related to motility and surface colonization in Pseudomonas putida. Disruption of fleQ caused strong defects in flagellar motility, biofilm formation and surface attachment, and the ability of this mutation to suppress multiple biofilm-related phenotypes associated to cyclic diguanylate overproduction suggests that FleQ mediates cyclic diguanylate signaling critical to biofilm growth. We have constructed a library containing 94 promoters potentially involved in motility and biofilm development fused to gfp and lacZ, screened this library for FleQ and cyclic diguanylate regulation, and assessed the involvement of alternative σ factors σN and FliA in the transcription of FleQ-regulated promoters. Our results suggest a dual mode of action for FleQ. Low cyclic diguanylate levels favor FleQ interaction with σN-dependent promoters to activate the flagellar cascade, encompassing the flagellar cluster and additional genes involved in cyclic diguanylate metabolism, signal transduction and gene regulation. On the other hand, characterization of the FleQ-regulated σN- and FliA-independent PlapA and PbcsD promoters revealed two disparate regulatory mechanisms leading to a similar outcome: the synthesis of biofilm matrix components in response to increased cyclic diguanylate levels.
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Affiliation(s)
- Alicia Jiménez-Fernández
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide/Consejo Superior de Investigaciones Científicas/Junta de Andalucía, Sevilla, Spain; and Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide, Carretera de Utrera, Km. 1, 41013, Sevilla, Spain
| | - Aroa López-Sánchez
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide/Consejo Superior de Investigaciones Científicas/Junta de Andalucía, Sevilla, Spain; and Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide, Carretera de Utrera, Km. 1, 41013, Sevilla, Spain
| | - Lorena Jiménez-Díaz
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide/Consejo Superior de Investigaciones Científicas/Junta de Andalucía, Sevilla, Spain; and Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide, Carretera de Utrera, Km. 1, 41013, Sevilla, Spain
| | - Blanca Navarrete
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide/Consejo Superior de Investigaciones Científicas/Junta de Andalucía, Sevilla, Spain; and Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide, Carretera de Utrera, Km. 1, 41013, Sevilla, Spain
| | - Patricia Calero
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide/Consejo Superior de Investigaciones Científicas/Junta de Andalucía, Sevilla, Spain; and Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide, Carretera de Utrera, Km. 1, 41013, Sevilla, Spain
| | - Ana Isabel Platero
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide/Consejo Superior de Investigaciones Científicas/Junta de Andalucía, Sevilla, Spain; and Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide, Carretera de Utrera, Km. 1, 41013, Sevilla, Spain
| | - Fernando Govantes
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide/Consejo Superior de Investigaciones Científicas/Junta de Andalucía, Sevilla, Spain; and Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide, Carretera de Utrera, Km. 1, 41013, Sevilla, Spain
- * E-mail:
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32
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Molina-Henares MA, Ramos-González MI, Daddaoua A, Fernández-Escamilla AM, Espinosa-Urgel M. FleQ of Pseudomonas putida KT2440 is a multimeric cyclic diguanylate binding protein that differentially regulates expression of biofilm matrix components. Res Microbiol 2016; 168:36-45. [PMID: 27503246 DOI: 10.1016/j.resmic.2016.07.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 07/15/2016] [Accepted: 07/18/2016] [Indexed: 01/06/2023]
Abstract
The intracellular signal molecule cyclic di-GMP (c-di-GMP) is an important element in regulation of biofilm formation by bacteria. In Pseudomonas aeruginosa, FleQ functions as a c-di-GMP-dependent transcriptional regulator of expression of flagellar genes and the exopolysaccharide (EPS) Pel, a component of the biofilm extracellular matrix. In the plant-beneficial bacterium Pseudomonas putida KT2440, a mutation in fleQ reduces biofilm formation and colonization of plant surfaces. Using isothermal titration calorimetry and electrophoretic mobility shift assays, we show in this work that FleQ of P. putida interacts with c-di-GMP and directly binds the promoter regions of flagellar and EPS genes. Data obtained by analytical gel filtration and ultracentrifugation indicate that FleQ is in multiple oligomeric states in solution (dimers, tetramers and hexamers), which do not show altered equilibrium in the presence of c-di-GMP. DNA binding is independent of c-diGMP, although it is favored by the second messenger in the case of the promoter of the operon responsible for synthesis of the species-specific EPS Pea. Analysis of expression using transcriptional fusions showed an influence of FleQ upon two of the four EPS operons under regular growth conditions. Finally, a consensus sequence for promoter recognition by FleQ in P. putida is also proposed.
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Affiliation(s)
- María Antonia Molina-Henares
- Department of Environmental Protection, Estación Experimental del Zaidín, CSIC, Profesor Albareda, 1, Granada 18008, Spain.
| | - María Isabel Ramos-González
- Department of Environmental Protection, Estación Experimental del Zaidín, CSIC, Profesor Albareda, 1, Granada 18008, Spain.
| | - Abdelali Daddaoua
- Department of Environmental Protection, Estación Experimental del Zaidín, CSIC, Profesor Albareda, 1, Granada 18008, Spain.
| | - Ana María Fernández-Escamilla
- Department of Environmental Protection, Estación Experimental del Zaidín, CSIC, Profesor Albareda, 1, Granada 18008, Spain.
| | - Manuel Espinosa-Urgel
- Department of Environmental Protection, Estación Experimental del Zaidín, CSIC, Profesor Albareda, 1, Granada 18008, Spain.
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Watters C, Fleming D, Bishop D, Rumbaugh KP. Host Responses to Biofilm. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2016; 142:193-239. [PMID: 27571696 DOI: 10.1016/bs.pmbts.2016.05.007] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
From birth to death the human host immune system interacts with bacterial cells. Biofilms are communities of microbes embedded in matrices composed of extracellular polymeric substance (EPS), and have been implicated in both the healthy microbiome and disease states. The immune system recognizes many different bacterial patterns, molecules, and antigens, but these components can be camouflaged in the biofilm mode of growth. Instead, immune cells come into contact with components of the EPS matrix, a diverse, hydrated mixture of extracellular DNA (bacterial and host), proteins, polysaccharides, and lipids. As bacterial cells transition from planktonic to biofilm-associated they produce small molecules, which can increase inflammation, induce cell death, and even cause necrosis. To survive, invading bacteria must overcome the epithelial barrier, host microbiome, complement, and a variety of leukocytes. If bacteria can evade these initial cell populations they have an increased chance at surviving and causing ongoing disease in the host. Planktonic cells are readily cleared, but biofilms reduce the effectiveness of both polymorphonuclear neutrophils and macrophages. In addition, in the presence of these cells, biofilm formation is actively enhanced, and components of host immune cells are assimilated into the EPS matrix. While pathogenic biofilms contribute to states of chronic inflammation, probiotic Lactobacillus biofilms cause a negligible immune response and, in states of inflammation, exhibit robust antiinflammatory properties. These probiotic biofilms colonize and protect the gut and vagina, and have been implicated in improved healing of damaged skin. Overall, biofilms stimulate a unique immune response that we are only beginning to understand.
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Affiliation(s)
- C Watters
- Wound Infections Department, Naval Medical Research Center, Silver Spring, MD, United States
| | - D Fleming
- Department of Surgery, Texas Tech University Health Sciences Center, Lubbock, TX, United States; Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, United States
| | - D Bishop
- Wound Infections Department, Naval Medical Research Center, Silver Spring, MD, United States
| | - K P Rumbaugh
- Department of Surgery, Texas Tech University Health Sciences Center, Lubbock, TX, United States; Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, United States.
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34
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Sub-Optimal Treatment of Bacterial Biofilms. Antibiotics (Basel) 2016; 5:antibiotics5020023. [PMID: 27338489 PMCID: PMC4929437 DOI: 10.3390/antibiotics5020023] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 05/08/2016] [Accepted: 06/13/2016] [Indexed: 01/22/2023] Open
Abstract
Bacterial biofilm is an emerging clinical problem recognized in the treatment of infectious diseases within the last two decades. The appearance of microbial biofilm in clinical settings is steadily increasing due to several reasons including the increased use of quality of life-improving artificial devices. In contrast to infections caused by planktonic bacteria that respond relatively well to standard antibiotic therapy, biofilm-forming bacteria tend to cause chronic infections whereby infections persist despite seemingly adequate antibiotic therapy. This review briefly describes the responses of biofilm matrix components and biofilm-associated bacteria towards sub-lethal concentrations of antimicrobial agents, which may include the generation of genetic and phenotypic variabilities. Clinical implications of bacterial biofilms in relation to antibiotic treatments are also discussed.
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35
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Ren GX, Fan S, Guo XP, Chen S, Sun YC. Differential Regulation of c-di-GMP Metabolic Enzymes by Environmental Signals Modulates Biofilm Formation in Yersinia pestis. Front Microbiol 2016; 7:821. [PMID: 27375563 PMCID: PMC4891359 DOI: 10.3389/fmicb.2016.00821] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 05/16/2016] [Indexed: 11/13/2022] Open
Abstract
Cyclic diguanylate (c-di-GMP) is essential for Yersinia pestis biofilm formation, which is important for flea-borne blockage-dependent plague transmission. Two diguanylate cyclases (DGCs), HmsT and HmsD and one phosphodiesterase (PDE), HmsP are responsible for the synthesis and degradation of c-di-GMP in Y. pestis. Here, we systematically analyzed the effect of various environmental signals on regulation of the biofilm phenotype, the c-di-GMP levels, and expression of HmsT, HmsD, and HmsP in Y. pestis. Biofilm formation was higher in the presence of non-lethal high concentration of CaCl2, MgCl2, CuSO4, sucrose, sodium dodecyl sulfate, or dithiothreitol, and was lower in the presence of FeCl2 or NaCl. In addition, we found that HmsD plays a major role in biofilm formation in acidic or redox environments. These environmental signals differentially regulated expression of HmsT, HmsP and HmsD, resulting in changes in the intracellular levels of c-di-GMP in Y. pestis. Our results suggest that bacteria can sense various environmental signals, and differentially regulate activity of DGCs and PDEs to coordinately regulate and adapt metabolism of c-di-GMP and biofilm formation to changing environments.
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Affiliation(s)
- Gai-Xian Ren
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College Beijing, China
| | - Sai Fan
- Institute of Nutrition and Food Hygiene, Beijing Centre for Disease Control and Prevention Beijing, China
| | - Xiao-Peng Guo
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College Beijing, China
| | - Shiyun Chen
- Key Laboratory of Special Pathogens and Biosafety, Center for Emerging Infectious Diseases, Wuhan Institute of Virology, Chinese Academy of Sciences Wuhan, China
| | - Yi-Cheng Sun
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College Beijing, China
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Prescott JF, Parreira VR, Mehdizadeh Gohari I, Lepp D, Gong J. The pathogenesis of necrotic enteritis in chickens: what we know and what we need to know: a review. Avian Pathol 2016; 45:288-94. [DOI: 10.1080/03079457.2016.1139688] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Abstract
The importance of cyclic di-GMP (c-di-GMP) and its control of biofilm matrix assembly and production has been a focal point of researchers in recent history. In this issue, Cooley et al. (Cooley RB, Smith TJ, Leung W, Tierney V, Borlee BR, O'Toole GA, Sondermann H, J Bacteriol 198:66-77, http://dx.doi.org/10.1128/JB.00369-15) demonstrate that two c-di-GMP controlled features of Pseudomonas aeruginosa, the periplasmic protease LapG and the surface adhesin CdrA, are linked. CdrA is shown to be a substrate of LapG, with LapG activity controlled by intracellular c-di-GMP levels. This commentary discusses the significance of this finding.
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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: 18] [Impact Index Per Article: 2.0] [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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Yuan X, Khokhani D, Wu X, Yang F, Biener G, Koestler BJ, Raicu V, He C, Waters CM, Sundin GW, Tian F, Yang CH. Cross-talk between a regulatory small RNA, cyclic-di-GMP signalling and flagellar regulator FlhDC for virulence and bacterial behaviours. Environ Microbiol 2015; 17:4745-63. [PMID: 26462993 DOI: 10.1111/1462-2920.13029] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Revised: 08/14/2015] [Accepted: 08/15/2015] [Indexed: 12/01/2022]
Abstract
Dickeya dadantii is a globally dispersed phytopathogen which causes diseases on a wide range of host plants. This pathogen utilizes the type III secretion system (T3SS) to suppress host defense responses, and secretes pectate lyase (Pel) to degrade the plant cell wall. Although the regulatory small RNA (sRNA) RsmB, cyclic diguanylate monophosphate (c-di-GMP) and flagellar regulator have been reported to affect the regulation of these two virulence factors or multiple cell behaviours such as motility and biofilm formation, the linkage between these regulatory components that coordinate the cell behaviours remain unclear. Here, we revealed a sophisticated regulatory network that connects the sRNA, c-di-GMP signalling and flagellar master regulator FlhDC. We propose multi-tiered regulatory mechanisms that link the FlhDC to the T3SS through three distinct pathways including the FlhDC-FliA-YcgR3937 pathway; the FlhDC-EcpC-RpoN-HrpL pathway; and the FlhDC-rsmB-RsmA-HrpL pathway. Among these, EcpC is the most dominant factor for FlhDC to positively regulate T3SS expression.
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Affiliation(s)
- Xiaochen Yuan
- Department of Biological Sciences, University of Wisconsin, Milwaukee, WI, 53211, USA
| | - Devanshi Khokhani
- Department of Biological Sciences, University of Wisconsin, Milwaukee, WI, 53211, USA
| | - Xiaogang Wu
- Department of Biological Sciences, University of Wisconsin, Milwaukee, WI, 53211, USA
| | - Fenghuan Yang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Gabriel Biener
- Department of Physics, University of Wisconsin, Milwaukee, WI, 53211, USA
| | - Benjamin J Koestler
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, 48824, USA
| | - Valerica Raicu
- Department of Biological Sciences, University of Wisconsin, Milwaukee, WI, 53211, USA.,Department of Physics, University of Wisconsin, Milwaukee, WI, 53211, USA
| | - Chenyang He
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Christopher M Waters
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, 48824, USA
| | - George W Sundin
- Department of Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing, MI, 48824, USA
| | - Fang Tian
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Ching-Hong Yang
- Department of Biological Sciences, University of Wisconsin, Milwaukee, WI, 53211, USA
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Wolska KI, Grudniak AM, Rudnicka Z, Markowska K. Genetic control of bacterial biofilms. J Appl Genet 2015; 57:225-38. [PMID: 26294280 PMCID: PMC4830867 DOI: 10.1007/s13353-015-0309-2] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 07/20/2015] [Accepted: 08/07/2015] [Indexed: 12/22/2022]
Abstract
Nearly all bacterial species, including pathogens, have the ability to form biofilms. Biofilms are defined as structured ecosystems in which microbes are attached to surfaces and embedded in a matrix composed of polysaccharides, eDNA, and proteins, and their development is a multistep process. Bacterial biofilms constitute a large medical problem due to their extremely high resistance to various types of therapeutics, including conventional antibiotics. Several environmental and genetic signals control every step of biofilm development and dispersal. From among the latter, quorum sensing, cyclic diguanosine-5'-monophosphate, and small RNAs are considered as the main regulators. The present review describes the control role of these three regulators in the life cycles of biofilms built by Pseudomonas aeruginosa, Staphylococcus aureus, Salmonella enterica serovar Typhimurium, and Vibrio cholerae. The interconnections between their activities are shown. Compounds and strategies which target the activity of these regulators, mainly quorum sensing inhibitors, and their potential role in therapy are also assessed.
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Affiliation(s)
- Krystyna I Wolska
- Department of Bacterial Genetics, Institute of Microbiology, Faculty of Biology, University of Warsaw, 1 Miecznikowa Street, 02-096, Warsaw, Poland
| | - Anna M Grudniak
- Department of Bacterial Genetics, Institute of Microbiology, Faculty of Biology, University of Warsaw, 1 Miecznikowa Street, 02-096, Warsaw, Poland
| | - Zofia Rudnicka
- Department of Bacterial Genetics, Institute of Microbiology, Faculty of Biology, University of Warsaw, 1 Miecznikowa Street, 02-096, Warsaw, Poland
| | - Katarzyna Markowska
- Department of Bacterial Genetics, Institute of Microbiology, Faculty of Biology, University of Warsaw, 1 Miecznikowa Street, 02-096, Warsaw, Poland.
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41
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Burns JL, Deer DD, Weinert EE. Oligomeric state affects oxygen dissociation and diguanylate cyclase activity of globin coupled sensors. MOLECULAR BIOSYSTEMS 2015; 10:2823-6. [PMID: 25174604 DOI: 10.1039/c4mb00366g] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Bacterial biofilm formation is regulated by enzymes, such as diguanylate cyclases, that respond to environmental signals and alter c-di-GMP levels. Diguanylate cyclase activity of two globin coupled sensors is shown to be regulated by gaseous ligands, with cyclase activity and O2 dissociation affected by protein oligomeric state.
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Affiliation(s)
- Justin L Burns
- Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, GA 30322, USA.
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Modification of a bi-functional diguanylate cyclase-phosphodiesterase to efficiently produce cyclic diguanylate monophosphate. ACTA ACUST UNITED AC 2015. [PMID: 28626712 PMCID: PMC5466042 DOI: 10.1016/j.btre.2015.04.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Cyclic-diGMP is a bacterial messenger that regulates many physiological processes, including many attributed to pathogenicity. Bacteria synthesize cyclic-diGMP from GTP using diguanylate cyclases; its hydrolysis is catalyzed by phosphodiesterases. Here we report the over-expression and purification of a bi-functional diguanylate cyclase-phosphodiesterase from Agrobacterium vitis S4. Using homology modeling and primary structure alignment, we identify several amino acids predicted to participate in the phosphodiesterase reaction. Upon altering selected residues, we obtain variants of the enzyme that efficiently and quantitatively catalyze the synthesis of cyclic-diGMP from GTP without hydrolysis to pGpG. Additionally, we identify a variant that produces cyclic-diGMP while immobilized to NiNTA beads and can catalyze the conversion of [α-32P]-GTP to [32P]-cyclic-diGMP. In short, we characterize a novel cyclic-diGMP processing enzyme and demonstrate its utility for efficient and cost-effective production of cyclic-diGMP, as well as modified cyclic-diGMP molecules, for use as probes in studying the many important biological processes mediated by cyclic-diGMP.
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43
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Chen R, Barphagha IK, Ham JH. Identification of potential genetic components involved in the deviant quorum-sensing signaling pathways of Burkholderia glumae through a functional genomics approach. Front Cell Infect Microbiol 2015; 5:22. [PMID: 25806356 PMCID: PMC4354385 DOI: 10.3389/fcimb.2015.00022] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2014] [Accepted: 02/22/2015] [Indexed: 12/21/2022] Open
Abstract
Burkholderia glumae is the chief causal agent for bacterial panicle blight of rice. The acyl-homoserine lactone (AHL)-mediated quorum-sensing (QS) system dependent on a pair of luxI and luxR homologs, tofI and tofR, is the primary cell-to-cell signaling mechanism determining the virulence of this bacterium. Production of toxoflavin, a major virulence factor of B. glumae, is known to be dependent on the tofI/tofR QS system. In our previous study, however, it was observed that B. glumae mutants defective in tofI or tofR produced toxoflavin if they grew on the surface of a solid medium, suggesting that alternative signaling pathways independent of tofI or tofR are activated in that growth condition for the production of toxoflavin. In this study, potential genetic components involved in the tofI- and tofR-independent signaling pathways for toxoflavin production were sought through screening random mini-Tn5 mutants of B. glumae to better understand the intercellular signaling pathways of this pathogen. Fifteen and three genes were initially identified as the potential genetic elements of the tofI- and tofR-independent pathways, respectively. Especially, the ORF (bglu_2g06320) divergently transcribed from toxJ, which encodes an orphan LuxR protein and controls toxoflavin biosynthesis, was newly identified in this study as a gene required for the tofR-independent toxoflavin production and named as toxK. Among those genes, flhD, dgcB, and wzyB were further studied to validate their functions in the tofI-independent toxoflavin production, and similar studies were also conducted with qsmR and toxK for their functions in the tofR-independent toxoflavin production. This work provides a foundation for future comprehensive studies of the intercellular signaling systems of B. glumae and other related pathogenic bacteria.
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Affiliation(s)
- Ruoxi Chen
- Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center Baton Rouge, LA, USA
| | - Inderjit K Barphagha
- Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center Baton Rouge, LA, USA
| | - Jong Hyun Ham
- Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center Baton Rouge, LA, USA
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Jiménez-Fernández A, López-Sánchez A, Calero P, Govantes F. The c-di-GMP phosphodiesterase BifA regulates biofilm development in Pseudomonas putida. ENVIRONMENTAL MICROBIOLOGY REPORTS 2015; 7:78-84. [PMID: 25870874 DOI: 10.1111/1758-2229.12153] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
We previously showed the isolation of biofilmpersistent Pseudomonas putida mutants that fail to undergo biofilm dispersal upon entry in stationary phase. Two such mutants were found to bear insertions in PP0914, encoding a GGDEF/EAL domain protein with high similarity to Pseudomon asaeruginosa BifA. Here we show the phenotypic characterization of a ΔbifA mutant in P. putida KT2442.This mutant displayed increased biofilm and pellicle formation, cell aggregation in liquid medium and decreased starvation-induced biofilm dispersal relative to the wild type. Unlike its P. aeruginosa counterpart, P. putida BifA did not affect swarming motility. The hyperadherent phenotype of the ΔbifA mutant correlates with a general increase in cyclic diguanylate (c-di-GMP) levels, Congo Red-binding exopolyaccharide production and transcription of the adhesin-encoding lapA gene. Integrity of the EAL motif and a modified GGDEF motif (altered to GGDQF)were crucial for BifA activity, and c-di-GMP depletion by overexpression of a heterologous c-di-GMP phosphodiesterase in the ΔbifA mutant restored wild-type biofilm dispersal and lapA expression.Our results indicate that BifA is a phosphodiesterase involved in the regulation of the c-di-GMP pool and required for the generation of the low c-di-GMP signal that triggers starvation-induced biofilm dispersal.
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Affiliation(s)
- Alicia Jiménez-Fernández
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide/Consejo Superior de Investigaciones Científicas/Junta de Andalucía, Carretera de Utrera, Km. 1, Sevilla 41013, Spain
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45
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Yaryura PM, Conforte VP, Malamud F, Roeschlin R, de Pino V, Castagnaro AP, McCarthy Y, Dow JM, Marano MR, Vojnov AA. XbmR, a new transcription factor involved in the regulation of chemotaxis, biofilm formation and virulence in Xanthomonas citri subsp. citri. Environ Microbiol 2014; 17:4164-76. [PMID: 25346091 DOI: 10.1111/1462-2920.12684] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Accepted: 10/19/2014] [Indexed: 12/22/2022]
Abstract
Xanthomonas citri subsp. citri (Xcc) is the causal agent of citrus canker. Biofilm formation on citrus leaves plays an important role in epiphytic survival of Xcc. Biofilm formation is affected by transposon insertion in XAC3733, which encodes a transcriptional activator of the NtrC family, not linked to a gene encoding a sensor protein, thus could be considered as an 'orphan' regulator whose function is poorly understood in Xanthomonas spp. Here we show that mutation of XAC3733 (named xbmR) resulted in impaired structural development of the Xcc biofilm, loss of chemotaxis and reduced virulence in grapefruit plants. All defective phenotypes were restored to wild-type levels by the introduction of PA2567 from Pseudomonas aeruginosa, which encodes a phosphodiesterase active in the degradation of cyclic diguanosine monophosphate (c-di-GMP). A knockout of xbmR led to a substantial downregulation of fliA that encodes a σ(28) transcription factor, as well as fliC and XAC0350 which are potential member of the σ(28) regulon. XAC0350 encodes an HD-GYP domain c-di-GMP phosphodiesterase. These findings suggest that XbmR is a key regulator of flagellar-dependent motility and chemotaxis exerting its action through a regulatory pathway that involves FliA and c-di-GMP.
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Affiliation(s)
- Pablo M Yaryura
- Instituto de Ciencia y Tecnología Dr. Cesar Milstein, Fundación Pablo Cassará, CONICET, Saladillo 2468, C1440FFX, Ciudad de Buenos Aires, Argentina
| | - Valeria P Conforte
- Instituto de Ciencia y Tecnología Dr. Cesar Milstein, Fundación Pablo Cassará, CONICET, Saladillo 2468, C1440FFX, Ciudad de Buenos Aires, Argentina
| | - Florencia Malamud
- Instituto de Ciencia y Tecnología Dr. Cesar Milstein, Fundación Pablo Cassará, CONICET, Saladillo 2468, C1440FFX, Ciudad de Buenos Aires, Argentina
| | - Roxana Roeschlin
- Instituto de Biología Molecular y Celular de Rosario (IBR)-Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET). Área Virología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Ocampo y Esmeralda, S2000FHN, Rosario, Argentina
| | - Verónica de Pino
- Instituto de Ciencia y Tecnología Dr. Cesar Milstein, Fundación Pablo Cassará, CONICET, Saladillo 2468, C1440FFX, Ciudad de Buenos Aires, Argentina
| | - Atilio P Castagnaro
- Estación Experimental Agroindustrial Obispo Colombres, Av. William Cross, 3150, Las Talitas, Tucumán, Argentina
| | - Yvonne McCarthy
- School of Microbiology, University College Cork, Cork, Ireland
| | - J Maxwell Dow
- School of Microbiology, University College Cork, Cork, Ireland
| | - María R Marano
- Instituto de Biología Molecular y Celular de Rosario (IBR)-Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET). Área Virología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Ocampo y Esmeralda, S2000FHN, Rosario, Argentina
| | - Adrián A Vojnov
- Instituto de Ciencia y Tecnología Dr. Cesar Milstein, Fundación Pablo Cassará, CONICET, Saladillo 2468, C1440FFX, Ciudad de Buenos Aires, Argentina
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Yang JG, Shih MS, Kuo WT, Chin KH, Shen GH, Chou SH. Crystallization of the N-terminal regulatory domain of the enhancer-binding protein FleQ from Stenotrophomonas maltophilia. ACTA CRYSTALLOGRAPHICA SECTION F-STRUCTURAL BIOLOGY COMMUNICATIONS 2014; 70:326-30. [PMID: 24598919 DOI: 10.1107/s2053230x14001514] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 01/21/2014] [Indexed: 11/10/2022]
Abstract
FleQ is a master regulator that controls bacterial flagellar gene expression. It is a unique enhancer-binding protein or repressor protein comprising an N-terminal FleQ domain, an AAA(+)/ATPase σ54-interaction domain and a helix-turn-helix DNA-binding domain. FleN is a putative ATPase with a deviant Walker A motif that works together with FleQ by binding to the FleQ N-terminal domain to fully express pel, psl and cdr operons in the presence of c-di-GMP to enhance biofilm formation. Stenotrophomonas maltophilia is an emerging human pathogen that causes fatal infections in humans. In order to understand the interaction between the FleN and FleQ domains and its effect on S. maltophilia biofilm formation, determination of the FleQ-c-di-GMP and FleN-FleQ-c-di-GMP complex structures was embarked upon. Towards this goal, the FleQ N-terminal domain from S. maltophilia was first cloned and expressed in Escherichia coli. Native and SeMet-labelled FleQ domains were successfully crystallized and diffracted to resolutions of 2.08 and 2.58 Å, respectively.
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Affiliation(s)
- Jauo-Guey Yang
- Institute of Biochemistry, National Chung Hsing University, Taichung 40227, Taiwan
| | - Min-Shao Shih
- Institute of Biochemistry, National Chung Hsing University, Taichung 40227, Taiwan
| | - Wei-Ting Kuo
- Institute of Biochemistry, National Chung Hsing University, Taichung 40227, Taiwan
| | - Ko-Hsin Chin
- Agricultural Biotechnology Center, National Chung Hsing University, Taichung 40227, Taiwan
| | - Gwan-Han Shen
- Department of Internal Medicine, Taichung Veterans General Hospital, Taichung, Taiwan
| | - Shan-Ho Chou
- Institute of Biochemistry, National Chung Hsing University, Taichung 40227, Taiwan
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Cyclic di-GMP: the first 25 years of a universal bacterial second messenger. Microbiol Mol Biol Rev 2013; 77:1-52. [PMID: 23471616 DOI: 10.1128/mmbr.00043-12] [Citation(s) in RCA: 1204] [Impact Index Per Article: 109.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Twenty-five years have passed since the discovery of cyclic dimeric (3'→5') GMP (cyclic di-GMP or c-di-GMP). From the relative obscurity of an allosteric activator of a bacterial cellulose synthase, c-di-GMP has emerged as one of the most common and important bacterial second messengers. Cyclic di-GMP has been shown to regulate biofilm formation, motility, virulence, the cell cycle, differentiation, and other processes. Most c-di-GMP-dependent signaling pathways control the ability of bacteria to interact with abiotic surfaces or with other bacterial and eukaryotic cells. Cyclic di-GMP plays key roles in lifestyle changes of many bacteria, including transition from the motile to the sessile state, which aids in the establishment of multicellular biofilm communities, and from the virulent state in acute infections to the less virulent but more resilient state characteristic of chronic infectious diseases. From a practical standpoint, modulating c-di-GMP signaling pathways in bacteria could represent a new way of controlling formation and dispersal of biofilms in medical and industrial settings. Cyclic di-GMP participates in interkingdom signaling. It is recognized by mammalian immune systems as a uniquely bacterial molecule and therefore is considered a promising vaccine adjuvant. The purpose of this review is not to overview the whole body of data in the burgeoning field of c-di-GMP-dependent signaling. Instead, we provide a historic perspective on the development of the field, emphasize common trends, and illustrate them with the best available examples. We also identify unresolved questions and highlight new directions in c-di-GMP research that will give us a deeper understanding of this truly universal bacterial second messenger.
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48
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Oxygen promotes biofilm formation of Shewanella putrefaciens CN32 through a diguanylate cyclase and an adhesin. Sci Rep 2013; 3:1945. [PMID: 23736081 PMCID: PMC3672883 DOI: 10.1038/srep01945] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Accepted: 05/20/2013] [Indexed: 11/09/2022] Open
Abstract
Although oxygen has been reported to regulate biofilm formation by several Shewanella species, the exact regulatory mechanism mostly remains unclear. Here, we identify a direct oxygen-sensing diguanylate cyclase (DosD) and reveal its regulatory role in biofilm formation by Shewanella putrefaciens CN32 under aerobic conditions. In vitro and in vivo analyses revealed that the activity of DosD culminates to synthesis of cyclic diguanylate (c-di-GMP) in the presence of oxygen. DosD regulates the transcription of bpfA operon which encodes seven proteins including a large repetitive adhesin BpfA and its cognate type I secretion system (TISS). Regulation of DosD in aerobic biofilms is heavily dependent on an adhesin BpfA and the TISS. This study offers an insight into the molecular mechanism of oxygen-stimulated biofilm formation by S. putrefaciens CN32.
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49
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Emerson D, Field EK, Chertkov O, Davenport KW, Goodwin L, Munk C, Nolan M, Woyke T. Comparative genomics of freshwater Fe-oxidizing bacteria: implications for physiology, ecology, and systematics. Front Microbiol 2013; 4:254. [PMID: 24062729 PMCID: PMC3770913 DOI: 10.3389/fmicb.2013.00254] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Accepted: 08/07/2013] [Indexed: 11/16/2022] Open
Abstract
The two microaerophilic, Fe-oxidizing bacteria (FeOB) Sideroxydans ES-1 and Gallionella ES-2 have single circular chromosomes of 3.00 and 3.16 Mb that encode 3049 and 3006 genes, respectively. Multi-locus sequence analysis (MLSA) confirmed the relationship of these two organisms to one another, and indicated they may form a novel order, the Gallionellalaes, within the Betaproteobacteria. Both are adapted for chemolithoautotropy, including pathways for CO2-fixation, and electron transport pathways adapted for growth at low O2-levels, an important adaptation for growing on Fe(II). Both genomes contain Mto-genes implicated in iron-oxidation, as well as other genes that could be involved in Fe-oxidation. Nearly 10% of their genomes are devoted to environmental sensing, signal transduction, and chemotaxis, consistent with their requirement for growing in narrow redox gradients of Fe(II) and O2. There are important differences as well. Sideroxydans ES-1 is more metabolically flexible, and can utilize reduced S-compounds, including thiosulfate, for lithotrophic growth. It has a suite of genes for nitrogen fixation. Gallionella ES-2 contains additional gene clusters for exopolysaccharide production, and has more capacity to resist heavy metals. Both strains contain genes for hemerythrins and globins, but ES-1 has an especially high numbers of these genes that may be involved in oxygen homeostasis, or storage. The two strains share homology with the marine FeOB Mariprofundus ferrooxydans PV-1 in CO2 fixation genes, and respiratory genes. In addition, ES-1 shares a suite of 20 potentially redox active genes with PV-1, as well as a large prophage. Combined these genetic, morphological, and physiological differences indicate that these are two novel species, Sideroxydans lithotrophicus ES-1T (ATCC 700298T; JCM 14762; DSMZ 22444; NCMA B100), and Gallionella capsiferriformans ES-2T (ATCC 700299T; JCM 14763; DSMZ 22445; NCMA B101).
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Affiliation(s)
- David Emerson
- Bigelow Laboratory for Ocean Sciences, East Boothbay Harbor ME, USA
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Zheng Y, Sambou T, Bogomolnaya LM, Cirillo JD, McClelland M, Andrews-Polymenis H. The EAL domain containing protein STM2215 (rtn) is needed during Salmonella infection and has cyclic di-GMP phosphodiesterase activity. Mol Microbiol 2013; 89:403-19. [PMID: 23734719 DOI: 10.1111/mmi.12284] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/30/2013] [Indexed: 12/22/2022]
Abstract
Salmonella Typhimurium gene STM2215 (rtn) is conserved among many enterobacteriaceae. Mutants lacking STM2215 poorly colonized the liver and spleen in intraperitoneal infection of mice and poorly colonized the intestine and deeper tissues in oral infection. These phenotypes were complemented by a wild-type copy of STM2215 provided in trans. STM2215 deletion mutants grew normally in J774A.1 murine macrophages but were unable to invade Caco-2 colonic epithelial cells. Consistent with this finding, mutants in STM2215 produced lower levels of effectors of the TTSS-1. STM2215 is a predicted c-di-GMP phosphodiesterase, but lacks identifiable sensor domains. Biochemical analysis of STM2215 determined that it is located in the inner membrane and has c-di-GMP phosphodiesterase activity in vitro dependent on an intact EAL motif. Unlike some previously identified members of this family, STM2215 did not affect motility, was expressed on plates, and in liquid media at late exponential and early stationary phase during growth. Defined mutations in STM2215 revealed that neither the predicted periplasmic domain nor the anchoring of the protein to the inner membrane is necessary for the activity of this protein during infection. However, the EAL domain of STM2215 is required during infection, suggesting that its phosphodiesterase activity is necessary during infection.
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Affiliation(s)
- Yi Zheng
- Department of Microbial and Molecular Pathogenesis, College of Medicine, Texas A&M University System Health Science Center, 8447 Hwy 47, Bryan, TX 77807, USA
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